# Regulatory Oversight Report for Uranium Mines and Mills in Canada: 2018

## Preface

The Regulatory Oversight Report for Uranium Mines and Mills in Canada: 2018 presents the assessment conducted by Canadian Nuclear Safety Commission (CNSC) staff of licensee performance at uranium mines and mills in Canada during the 2018 calendar year. This report also provides an update on CNSC staff’s regulatory activities related to public information, community engagement and aspects of the CNSC’s Independent Environmental Monitoring Program that relate to uranium mines and mills. Where possible, trends are shown and information is compared to previous years.

CNSC staff use 14 safety and control areas (SCAs) to evaluate the performance of each licensee. This report provides performance ratings for all 14 SCAs for uranium mines and mills. This report provides specific details about the three SCAs that contain the majority of the key performance indicators for these facilities: radiation protection, environmental protection, and conventional health and safety.

The SCA ratings in this report are derived from the results of compliance activities conducted by CNSC staff. These activities include onsite inspections, technical assessments, reviews of reports submitted by licensees, event and incident reviews, and ongoing exchanges of information with licensees. For the 2018 reporting year, CNSC staff rated all SCAs as satisfactory for all uranium mines and mills, with the exception of the McClean Lake radiation protection SCA which continued to be rated fully satisfactory.

CNSC staff confirmed that all uranium mine and mill facilities in Canada operated safely during 2018.

CNSC staff concluded that the licensees of the regulated facilities covered in this report have made adequate provision for the health and safety of workers, the protection of the public and the environment, and Canada’s international obligations. The documents referenced in this report are available to the public upon request.

## Clear Language Summary

The Regulatory Oversight Report for Uranium Mines and Mills in Canada: 2018 provides information about the CNSC’s work ensuring the safety and protection of people and the environment near operating uranium mines and mills in Canada, all of which are located in northern Saskatchewan. These uranium mines and mills continued to operate safely in 2018. Monitoring continues to show that the country foods and water surrounding the mines and mills remain safe to eat and drink. There were no releases that could have harmed human health or the environment.

This report provides information on the following uranium mines and mills in Saskatchewan:

• Cigar Lake – operating uranium mine
• McArthur River – uranium mine in care and maintenance
• Rabbit Lake – uranium mine and mill in care and maintenance
• Key Lake – uranium mill in care and maintenance
• McClean Lake – operating uranium mill

When in a state of care and maintenance, a mine and/or mill is not mining, milling or processing uranium ore, and it is not producing uranium concentrate (yellowcake). These facilities still have sufficient staff to perform ongoing maintenance, water treatment and protection of employees, the public and the environment.

Each year, CNSC inspectors conduct inspections at uranium mines and mills. The number and focus of the inspections depend on the performance and operating status of the mine or mill. The CNSC uses a risk-informed approach when planning inspections. In 2018, CNSC staff performed a total of 26 inspections across the five mines and mills. As a result of these inspections, 31 non-compliances or action notices were issued. All concerns raised during the inspections have been addressed by the operators.

Although the CNSC evaluates operating nuclear facilities across 14 functional areas, this report focuses on the following three areas:

• Radiation protection: In 2018, the maximum individual radiation dose to a worker at any of the five uranium mine and mill facilities was only 14 percent of the annual regulatory limit. No workers exceeded their regulatory radiation dose limit.
• Environmental protection: CNSC licensees are required to report any unauthorized release of hazardous substances or nuclear materials to the environment to the CNSC and other regulatory authorities. In 2018, a total of 20 unauthorized releases were reported. This is in the normal range of releases for uranium mines and mills. Corrective actions were taken by the mine or mill operators in response to each release. There was no lasting impact to the environment as a result of these spills. Each facility uses water as part of the mining and milling process. All water used in the operation must be treated before being discharged back to the environment. All discharged water met the federal or provincial discharge requirements, ensuring that the persons near the facility are safe.
• Conventional health and safety: All mining and milling operations must report any lost‑time, workplace-related injuries to the CNSC and provincial agencies. In 2018, only one injury required reporting, which is consistent with previous years.

### Indigenous and community engagement

As an agent of the Government of Canada, the CNSC recognizes and understands the importance of building relationships with Indigenous peoples in Canada. The CNSC's goal is to build partnerships and trust with Indigenous communities through collaborative ongoing engagement activities related to CNSC-regulated facilities and activities of interest within their traditional and/or treaty territories. The uranium mines and mills discussed in this report lie within Treaty 8 and Treaty 10 and MÃ©tis Nation-Saskatchewan Northern Region 1, as well as the traditional territories of many Indigenous communities.

In 2018, CNSC staff efforts supported their ongoing commitment to meeting consultation and engagement obligations and continuing to build relationships with Indigenous peoples with interests in Canada’s uranium mines and mills.

In 2019, following the recommendations of the Commission, CNSC staff took the initiative to meet with Indigenous groups and communities before the public consultation period to provide information and identify potential improvements to the regulatory oversight report.

### In summary:

• Workers at each facility were safe and properly protected.
• There were no releases that could have harmed the environment or the health and safety of people nearby.
• Airborne radiation was not increased as a result of these facilities.
• All water released from the facility was safe.
• Fish and plants were safe to eat.

## 1. Introduction

### 1.1 Background

The Canadian Nuclear Safety Commission (CNSC) regulates Canada’s uranium mines and mills to protect health, safety, security and the environment; to implement Canada’s international commitments on the peaceful use of nuclear energy; and to disseminate objective scientific, technical and regulatory information to the public. This mandate is derived from the Nuclear Safety and Control Act (NSCA) [1], which along with its regulations, contains requirements with which CNSC licensees must comply.

Each year the CNSC produces a regulatory oversight report on the operating performance of Canada’s uranium mine and mill licensees and licensed facilities. This report includes data for the 2018 calendar year for uranium mines and mills. Every third year, the CNSC report also includes updates on historic and decommissioned uranium mine and mill sites. Data for historic and decommissioned sites was presented in the Regulatory Oversight Report for Uranium Mines, Mills, Historic and Decommissioned Sites in Canada: 2017 and will be presented again in 2020.

This report:

• describes the CNSC’s regulatory efforts, public information and community engagement activities, and Independent Environmental Monitoring Program (IEMP)
• includes information on licensee operation, licence changes, major developments at licensed facilities, as well as any significant events
• presents the performance rating for each safety and control area (SCA) for uranium mine and mill facilities regulated by the CNSC
• presents performance data on the radiation protection, environmental protection and conventional health and safety SCAs for each licensed facility

This report summarizes CNSC staff’s assessment of the following regulated uranium mine and mill facilities:

• Cigar Lake Operation
• McArthur River Operation
• Rabbit Lake Operation
• Key Lake Operation
• McClean Lake Operation

Throughout the review period, CNSC staff continued to conduct compliance activities, including onsite inspections, technical assessments, reviews of reports submitted by licensees, event and incident reviews and ongoing exchanges of information with the licensees of all uranium mine and mill facilities.

### 1.2 CNSC regulatory efforts

#### 1.2.1 Licensing

The CNSC regulates each uranium mine and mill under a separate licence. An approved licence under the NSCA [1] defines licence terms, licensed activities and licence conditions. Tables summarizing the uranium mine and mill licences can be found in appendix A. In July 2018, a Commission panel approved the change of the licensee name from AREVA Resources Canada Inc. (AREVA) to Orano Canada Inc. and issued the amended licence UMOL-MINEMILL-McCLEAN.01/2027. Each CNSC licence is accompanied by a licence conditions handbook (LCH) which contains compliance verification criteria used by CNSC staff to ensure compliance with the conditions set out in the licence. All changes made to the LCHs during this review period are also provided in appendix A.

#### 1.2.2 Regulatory developments

CNSC staff continue to modernize the regulatory framework with the REGDOC series of regulatory and guidance documents. Licensees continue to be in compliance with the regulatory documents or applicable standards identified in their licence conditions handbooks during the transition process. The licensees are on track for meeting all deadlines established. CNSC staff continue to monitor progress through regular licensing meetings.

Table 1.1 lists the updates made to the CNSC regulatory documents since 2016 that apply to the uranium mine and mill licensees and includes the implementation status.

Table 1.1: Regulatory documents applicable to uranium mine and mill facilities
Regulatory document Cigar Lake McArthur River Rabbit Lake Key Lake McClean Lake
REGDOC-2.2.2, Personnel Training, Version 2
December 2016
To be implemented as part of 2021 licence renewal To be implemented in 2019 Implementation to be completed June 2022 Implementation to be completed June 2022 Implemented
REGDOC-2.10.1, Nuclear Emergency Preparedness and Response, Version 2
February 2017
To be implemented as part of 2021 licence renewal Implementation plan to be submitted in 2020 Implementation plan to be submitted in 2020 Implementation plan to be submitted in 2020 Implemented
REGDOC-2.9.1, Environmental Protection: Environmental Principles, Assessments and Protection Measures, Version 1.1,
April 2017
To be implemented as part of 2021 licence renewal Implementation plan expected in 2020 Implementation to be completed June 2022 Implementation to be completed June 2022 Implementation to be completed June 2020
REGDOC-1.6.1, Licence Application Guide: Nuclear Substances and Radiation Devices, Version 2,
May 2017
To be implemented as part of 2021 licence renewal Implemented Implementation to be completed June 2022 Implementation to be completed June 2022 Implemented
REGDOC-3.1.2, Reporting Requirements, Volume I: Non-Power Reactor Class I Nuclear Facilities and Uranium Mines and Mills
January 2018
To be implemented as part of 2021 licence renewal Implemented Implementation to be completed June 2022 Implementation to be completed June 2022 Implementation to be completed June 2022
REGDOC-2.13.1, Safeguards and Nuclear Material Accountancy
February 2018
To be implemented as part of 2021 licence renewal Implementation plan to be submitted by January 2020 Implementation plan to be submitted by January 2020 Implementation plan to be submitted by January 2020 Implementation to be completed June 2022
REGDOC-2.5.4, Design of Uranium Mines and Mills: Ventilation Systems
March 2018
To be implemented as part of 2021 licence renewal Implemented Implementation plan to be submitted by January 2020 Implementation plan to be submitted by January 2020 Implementation plan to be submitted by January 2020
REGDOC-2.1.2, Safety Culture
April 2018
Implementation to be completed June 2022 Implementation to be completed June 2022 Implementation to be completed June 2022 Implementation to be completed June 2022 Implementation to be completed June 2022
REGDOC-3.2.1, Public Information and Disclosure
May 2018
To be implemented as part of 2021 licence renewal Implementation plan to be submitted in 2020 Implementation plan to be submitted in 2020 Implementation plan to be submitted in 2020 Implementation plan to be submitted in 2020
REGDOC-2.11.1, Waste Management, Volume III: Assessing the Long-Term Safety of Radioactive Waste Management
May 2018
Not applicable Not applicable Implementation plan to be submitted in January 2020 Implementation plan to be submitted in January 2020 Implementation plan to be submitted in January 2020
REGDOC-2.11.1, Waste Management, Volume II: Management of Uranium Mine Waste Rock and Mill Tailings
November 2018
To be implemented as part of 2021 licence renewal Implemented Implementation plan to be submitted in January 2020 Implementation plan to be submitted in January 2020 Implementation plan to be submitted in January 2020

#### 1.2.3 Compliance

The CNSC ensures licensee compliance through verification, enforcement and reporting activities. CNSC staff develop compliance plans for each facility commensurate with the associated risk and implement these plans by conducting regulatory activities which include onsite inspections and technical assessments of licensee programs, processes and reports. Changes to compliance plans are made on an ongoing basis in response to events, facility modifications and changes in licensee performance.

Figure 1.1 shows a CNSC inspector presenting a preliminary facts and findings report to a licensee following an inspection at the Cigar Lake Operation.

Table 1.2 presents data on CNSC staff inspections conducted at uranium mines and mills. Instances of non-compliance noted during these inspections were provided to the licensees in detailed inspection reports and recorded in the CNSC Regulatory Information Bank in order to ensure that corrective actions were tracked to completion. Examples of non-compliance include: failure to wear radiation monitoring equipment, non-compliance with the National Fire Code, failure to follow procedures; additional training needs identified and incorrect or incomplete labelling or signage.

Table 1.2: Compliance inspections at uranium mines and mills
Year Inspections Instances of non-compliance
2018 26 31
2017 30 23
2016 30 41
2015 30 37
2014 24 31

All instances of non-compliance identified were of low safety significance. Safety significance is determined based on comparison to criteria developed and used in the CNSC Regulatory Information Bank. Examples of the criteria are included in the appendices to this report in tables H-2, I-2, J-2 and K-2. Additional details on the inspections covered in this reporting period can be found in appendix B. CNSC staff assessed the licensees’ corrective actions taken in response to the identified instances of non-compliance and verified that these actions were appropriate and acceptable. All instances of non‑compliance were addressed appropriately by the licensees to meet all regulatory requirements and have been closed by CNSC staff.

Other regulatory bodies that conduct inspections at the facilities include the Saskatchewan Ministry of Environment, the Saskatchewan Ministry of Labour Relations and Workplace Safety, and Environment and Climate Change Canada. These regulatory bodies focus primarily on the areas of conventional health and safety, and environmental protection. CNSC staff take into account the findings from these regulatory bodies when assessing licensees’ performance. When logistically reasonable, joint inspections are conducted with other federal, provincial or territorial regulatory agencies.

#### 1.2.4 Safety and control area framework

SCAs are the technical topics that CNSC staff use across all regulated facilities and activities to assess, evaluate, review, verify and report on regulatory requirements and performance. The CNSC’s SCA framework which staff use to evaluate licensee safety performance includes 14 SCAs. Each SCA is subdivided into specific areas that define its key components. Appendix C provides definitions of these SCAs and their specific areas.

CNSC staff use the following four ratings, defined in appendix D, to grade licensee performance in each applicable SCA:

• fully satisfactory (FS)
• satisfactory (SA)
• below expectations (BE)
• unacceptable (UA)

This report contains CNSC staff’s performance ratings for all applicable SCAs, with a focus on three SCAs that cover many of the key performance indicators for mining and milling operations: radiation protection, environmental protection, and conventional health and safety.

For 2018, all SCA performance ratings for uranium mines and mills were rated satisfactory, with the exception of radiation protection at the McClean Lake Operation which continues to be rated fully satisfactory.

CNSC staff concluded, based on the results of regulatory oversight activities, that uranium mine and mill facilities met the following requirements:

• Radiation protection measures were effective and radiation doses received by workers remained as low as reasonably achievable (ALARA). As a result:
• No worker doses exceeded regulatory effective dose limits.
• Where action level exceedances occurred, they were reported and investigated to determine the causes, and corrective actions were identified by the licensee. At the time of writing, CNSC staff were in the process of assessing the corrective actions that the licensee reported as complete. Additional corrective actions are scheduled to be completed by the licensee in early 2020 and will be assessed through ongoing CNSC compliance activities.
• Environmental protection programs were effective, and as a result, emissions and effluents remained ALARA:
• Where action level exceedances occurred, they were reported and investigated. Corrective measures were implemented by the licensee and verified by CNSC staff.
• Conventional health and safety programs continued to protect workers:
• Where a lost-time injury (LTI) was reported, corrective measures were implemented by the licensee and verified by CNSC staff.

Appendix E contains the SCA performance ratings for the 2014–18 reporting period for uranium mines and mills.

#### 1.2.5 Independent Environmental Monitoring Program

Under the NSCA [1], the CNSC requires that each nuclear facility licensee develops, implements and maintains an environmental monitoring program to demonstrate that the public and the environment are protected from any releases to the environment relating to the facility’s nuclear activities. CNSC staff evaluate and assess the results of these monitoring programs to ensure compliance with the applicable requirements and limits, as set out in the regulations that govern Canada’s nuclear industry.

The CNSC implements an Independent Environmental Monitoring Program (IEMP) to verify that all persons and the environment around licensed nuclear facilities are protected. The IEMP is a regulatory tool that complements and informs the CNSC’s ongoing compliance verification program. The IEMP does not rely on licensees to provide samples; CNSC staff or independent contractors obtain samples from publicly accessible areas around nuclear facilities, then measure and report the amounts of radiological and hazardous substances present in these samples to the Commission and/or the public.

No IEMP sampling campaigns were held at the uranium mines and mills in 2018. Results from previous IEMP sampling campaigns are available on the CNSC’s IEMP web page.

### 1.3 Public information and Indigenous engagement

The availability and clarity of information pertaining to nuclear activities are essential to establishing an atmosphere of openness, transparency and trust between the licensee and the public. Since 2012, the CNSC requires major licensees to maintain a Public Information and Disclosure Program (PIDP) supported by a robust disclosure protocol that addresses local communities’ and stakeholders’ needs.

CNSC regulatory document REGDOC-3.2.1, Public Information and Disclosure, [2] (formerly RD/GD-99.3) sets out the requirements for public information and disclosure. The primary goal of the program, as it relates to the licensed activities, is to ensure that information related to the health, safety and security of persons and the environment, and other issues associated with the lifecycle of nuclear facilities are effectively communicated to the public. This information promotes transparency and gives the public a better understanding of the licensed activities and operations. The program includes a commitment and protocol for the ongoing, timely dissemination of information related to the licensed facility during the licence period.

In 2018, licensees continued to communicate regularly with interested communities. As part of the public information program, licensees regularly participate in meetings of the Northern Saskatchewan Environmental Quality Committee (EQC) and facility tours. The EQC represents more than 30 communities across the greater northern Saskatchewan region. The EQC, established in 1995, allows northerners to learn more about uranium mining activities and the environmental protection measures in place. Further information about the EQC can be found on its web page.

The following are some key activities and best practices noted among licensees in 2018:

• Cameco upheld commitments to be open and transparent with its stakeholders. Cameco promptly provided material on its website about onsite events of interest to its audiences, operations and regular licensed activities. Cameco hosted a variety of community information sessions and remains compliant with regulatory requirements.
• Orano continued to meet the commitments made in its public information program by providing the public with updated information about its regular operations in advance of the Cluff Lake Project licence renewal. Many company representatives hold project-specific dialogues which are captured in a database that tracks requested information and over time provides a better understanding of the public’s areas of interest and concerns.
• Cameco and Orano collaborated to host a special engagement workshop with the communities signatory to the Athabasca collaboration agreement. The purpose was to have open dialogue about upcoming decommissioning activities and financial guarantees, and to identify effective ways to maintain strong communications between the licensees and the local communities.

CNSC staff evaluated Cameco’s and Orano’s public information and disclosure programs throughout 2018 and determined that the uranium mine and mill facilities complied with the requirements set out in CNSC REGDOC-3.2.1, Public Information and Disclosure [2].

CNSC staff assessed licensee activities and conducted regular reviews of the public information and disclosure programs through compliance verification activities, such as desktop reviews, inspections, and by observing community meetings. CNSC staff determined that Cameco and Orano provided information on the status of their facilities through a variety of communication activities and products. Some activities implemented by the licensees included providing facility updates to community committees, holding northern tour public information sessions, disclosing onsite events, offering facility tours, organizing and participating in community events, preparing newsletters and promoting activities and public engagement using social media. CNSC staff determined that Cameco and Orano customize their communications to be primarily in person, given the local communities’ communication preference. Each organization has made efforts to be present in the community, host local meetings and participate regularly in local committees to ensure that clear, effective and two-way information is shared.

In 2018, CNSC staff continued to keep the public and Indigenous communities informed of our regulatory activities through regular website updates, local magazine updates, publicly webcast Commission proceedings, social media and regular face-to-face discussion with key audiences in northern Saskatchewan, including the EQC (described below).

#### Indigenous consultation and engagement

As an agent of the Government of Canada, the CNSC recognizes and understands the importance of consulting and building relationships with Indigenous Peoples in Canada. The CNSC's goal is to build partnerships and trust with Indigenous communities through collaborative ongoing engagement activities related to CNSC-regulated facilities and activities of interest within their traditional and/or treaty territories. Cameco’s and Orano’s facilities lie within Treaty 8 and Treaty 10 and MÃ©tis Nation-Saskatchewan Northern Region 1, as well as the traditional territories of many Indigenous communities.

The CNSC's Indigenous engagement practices, which include information sharing and funding support through the CNSC's Participant Funding Program (PFP), are meant to help Indigenous Peoples meaningfully participate in Commission proceedings and ongoing regulatory activities. These practices are consistent with the principles of upholding the honour of the Crown and reconciliation.

CNSC staff efforts in 2018 supported the CNSC’s ongoing commitment to meeting its consultation and engagement obligations and building relationships with the Indigenous Peoples with interests in Canada’s uranium mines and mills.

In 2018, participant funding was awarded to six Indigenous groups to assist in their review and comment of the Regulatory Oversight Report for Uranium Mines, Mills, Historic and Decommissioned Sites in Canada: 2017. These groups were: the English River First Nation, the Ya’thi NÃ©nÃ© Land and Resource Office, Algonquins of Ontario, Sagamok Anishinabek First Nation, the Athabasca Chipewyan First Nation and the Prince Albert Grand Council.

In 2018, CNSC staff continued to work with Indigenous communities and organizations to identify opportunities for formalized and regular engagement throughout the lifecycle of these operations, including meetings and facilitated workshops. CNSC staff met with Indigenous communities to discuss areas of interest, such as Orano’s proposed uranium mine decommissioning licence renewal for the Cluff Lake Project and Cameco’s proposed waste facility operating licence amendment for the Beaverlodge Project. In addition, CNSC staff carried out the following engagement activities, including meetings with the public and Indigenous groups in 2018:

• participation in meetings of the Northern Saskatchewan Environmental Quality Committee
• participation in a meeting with Indigenous communities hosted by Cameco and Orano in Saskatoon on June 6 and 7, 2018, at which CNSC staff presented and answered questions about the CNSC, the Uranium Mines and Mills Regulations [7], public and Indigenous engagement, and the PFP
• participation in the Saskatchewan Mining Association Annual Conference and environmental forum
• meetings with Indigenous groups to provide information on the Regulatory Oversight Report for Uranium Mines, Mills, Historic and Decommissioned Sites in Canada: 2017

To ensure that licensees engage with Indigenous communities, the CNSC published REGDOC‑3.2.2, Aboriginal Engagement [3], in 2016. REGDOC-3.2.2 sets out requirements and guidance for licensees proposing projects that may raise the Crown’s duty to consult. Throughout this reporting period, licensees continued to host meetings and to discuss their operations with Indigenous communities. CNSC staff participated in many of these meetings, verified the engagement work conducted by Cameco and Orano, and ensured that they actively engaged and communicated with Indigenous groups that have interest in their facilities.

CNSC staff confirmed that Cameco and Orano have well established Indigenous engagement and outreach programs and engage with the following Indigenous groups that have interests in their facilities: Athabasca Chipewyan First Nation, Clearwater River Dene Nation, English River First Nation, Buffalo River Dene Nation, Birch Narrows Dene Nation, Lac La Ronge Indian Band, MÃ©tis Nation-Saskatchewan, Pinehouse Kineepik MÃ©tis, Prince Albert Grand Council, and the Athabasca Dene communities of Hatchet Lake First Nation, Black Lake First Nation and Fond du Lac First Nation that are represented by the Ya’thi NÃ©nÃ© Land and Resource Office.

CNSC staff are satisfied with the level and quality of Indigenous engagement conducted by Cameco and Orano regarding their uranium mine and mill operations in northern Saskatchewan.

In 2019 as a result of recommendations from the Commission, CNSC staff took the initiative to meet with Indigenous groups and communities before the public consultation period to provide information and seek opportunity for improvement on the regulatory oversight report (figures 1.3 and 1.4). In addition, using feedback from the Indigenous engagement, a plain language overview was prepared and included in this report. First Nation and MÃ©tis communities with interests in Canada’s uranium mines and mills were provided a copy of this regulatory oversight report. Through the CNSC’s PFP, financial support was made available for participation in the review of this report.

CNSC staff will continue to engage with and update interested Indigenous communities on regulatory activities and are committed to providing key updates on nuclear activities and projects in their territories of interest.

### 1.4 National Pollutant Release Inventory

Appendix L shows the total annual release of relevant radionuclides to the environment from these facilities from 2014 to 2018.

## 2. Overview

This section of the report focuses on the performance of the five uranium mines and mills in Canada in 2018. Three of the five facilities are currently in a state of care and maintenance. The facilities listed are located within the Athabasca Basin of northern Saskatchewan and are shown in figure 2.1:

• Cigar Lake Operation (mine)
• McArthur River Operation (mine – care and maintenance )
• Rabbit Lake Operation (mine and mill – care and maintenance)
• Key Lake Operation (mill – care and maintenance)
• McClean Lake Operation (mine and mill)

In 2016, the Rabbit Lake mine and mill, operated by Cameco, entered into care and maintenance mode and has remained in this state since that time.

On November 8, 2017, Cameco notified the CNSC that effective January 2018, it would be temporarily suspending production at the Key Lake and McArthur River Operations. This included all activities directly related to mining and processing uranium ore. On July 25, 2018, Cameco notified the CNSC of its decision to suspend production at the Key Lake and McArthur River Operations indefinitely, until economic conditions improve. During this suspension of production (care and maintenance), work is ongoing, with sufficient qualified staff (about 100 persons) remaining at each facility to ensure the protection of people and the environment. Water treatment continues, ensuring that any discharges are meeting the performance criteria and respecting all federal and provincial limits. For mine workings, the licensee conducts regular inspections to assess ground stability, ventilation and dewatering of accessible areas of the mine. In the mill, systems and services require continued maintenance to ensure that they remain operational. Therefore, even though the facilities are in a care and maintenance mode, substantial work is ongoing at each location.

As the licensee transitions to care and maintenance mode, CNSC staff review the reductions in staff and changes in service levels to ensure that there is no overall decrease in the safety of the facilities. A reduction in staff may translate to one person taking on one or more additional roles. CNSC inspectors review the training provided to confirm that the licensee continues to maintain sufficient qualified staff. For example, licensee staff not familiar with conducting measurements or taking samples would have to receive the appropriate training and become qualified to perform those additional tasks. CNSC inspectors use criteria in their inspections to confirm that staffing levels remain appropriate and that workers have the capability and the time needed to perform all expected functions.

Where the licensee reduces a service, such as ventilation volumes, CNSC staff evaluate how the reduction will impact workers in the area. CNSC staff also ensure that sufficient protective measures, including alarming detectors, are in place to warn of potentially unsafe situations. Licensees continue to train workers to understand both the safety implications of the monitors and the actions they need to take if any condition triggers an alarm. CNSC specialists are involved in the review of changes which may impact licensed activities to ensure that the licensee maintains an equivalent level of safety.

In 2018, CNSC staff continued routine compliance verification inspections at all facilities to ensure that the licensee continues to meet regulatory expectations and to verify that safety is not compromised by the changes implemented during the transition to care and maintenance. CNSC staff concluded that the operations were safely suspended, and workers, the public and the environment continued to be protected. CNSC staff will continue to use a risk-informed approach for regulatory oversight.

The 2018 uranium production data for uranium mine and mill facilities are shown in table 2.1. CNSC staff confirmed that all facilities operated within their authorized annual production limits in 2018. Production data for the McArthur River Operation and the Key Lake Operation was lower than previous years because production was suspended in early 2018.

Table 2.1: Mining and milling production data for uranium mines and mills, 2018
Production data Cigar Lake McArthur River Rabbit Lake1 KeyLake2 McClean Lake3
Mining – ore tonnage (Mkg/year) 43.06 2.79 0 0 0
Mining – average ore grade mined (%U) 16.1 7.57 0 N/A N/A
Mining – U mined (Mkg U/year) 6.94 0.18 0 0 0
Milling – mill ore feed (Mkg/year) N/A N/A 0 0 42.9
Milling – average mill feed grade (%U) N/A N/A 0 0 16.26
Milling – mill recovery (%U) N/A N/A 0 N/A2 98.94
Milling – U concentrate produced (Mkg U/year) N/A N/A 0 0.062 6.94
Authorized annual production (Mkg U/year) 9.25 9.6 4.25 9.6 9.23

1 Rabbit Lake is currently in a safe state of care and maintenance.

2 Key Lake did not feed ore in 2018 and only processed material already in the mill process.

3 The McClean Lake mill was designed to mill high-grade ore from Cigar Lake without any blending or dilution.

N/A = Not applicable.

Mkg = 1,000,000 kg

Licensees are required to develop preliminary decommissioning plans and associated financial guarantees to ensure that work activities are covered financially and that work is guaranteed to completion with no liability to the government. Financial guarantee values for the mine and mill facilities range from approximately C$48 million at the McArthur River Operation to C$218 million at the Key Lake Operation. The values of the financial guarantees for each uranium mine and mill are listed in appendix F. Financial guarantees cover all costs necessary to fully decommission and remediate a uranium mine and/or mill to ensure the protection of people and the environment.

### 2.1 Regulatory efforts

The CNSC regulates the five uranium mine and mill operations under separate licences. Appendix A provides an outline of these licences and their respective licensing information.

In 2018, CNSC staff performed four to six inspections at each uranium mine and mill, for a total of 26 onsite inspections (these are outlined in appendix B). As a result of these inspections, 31 instances of non-compliance were identified, all of low safety significance. Examples of non-compliance include: failure to wear radiation monitoring equipment; non-compliance with the National Fire Code; failure to follow procedures; identification of additional training needs; and incorrect or incomplete labelling or signage.

CNSC staff assessed all corrective actions taken by licensees in response to non-compliance and verified that these actions were appropriate and acceptable. All non-compliances are considered closed. The following figure shows CNSC staff gathering information from a Cameco health and safety representative during a compliance inspection.

### 2.2 Performance

CNSC staff use expert professional judgment to rate safety and control area (SCA) performance at uranium mine and mill facilities. Ratings are based on the review of key performance indicators (e.g., accident/event occurrences, responses to accidents/events, desktop review of reports, dose information, environmental (radiological and non-radiological) results) and the results of compliance activities, such as inspections and technical assessments.

Once established, the ratings are compared across all five mines and mills and to the rating definitions in appendix D to ensure that consistent and defendable ratings are assigned. The SCA performance ratings for the mine and mill facilities are presented in table 2.2; the SCA ratings for each facility from 2014 to 2018 are in appendix E.

Table 2.2: SCA performance ratings for uranium mines and mills, 2018
Safety and control area Cigar Lake McArthur River Rabbit Lake Key Lake McClean Lake
Management system SA SA SA SA SA
Human performance management SA SA SA SA SA
Operating performance SA SA SA SA SA
Safety analysis SA SA SA SA SA
Physical design SA SA SA SA SA
Fitness for service SA SA SA SA SA
Radiation protection SA SA SA SA FS
Conventional health and safety SA SA SA SA SA
Environmental protection SA SA SA SA SA
Emergency management and fire protection SA SA SA SA SA
Waste management SA SA SA SA SA
Security SA SA SA SA SA
Safeguards and non‑proliferation SA SA SA SA SA
Packaging and transport SA SA SA SA SA
FS = fully satisfactory SA = satisfactory

This report provides details about three SCAs that cover many of the key performance indicators for these facilities. The SCAs are: radiation protection, environmental protection, and conventional health and safety.

Licensees develop and maintain management systems that include integrated links to all 14 SCAs. Management systems are the framework that establish the processes and programs required to ensure an organization achieves its safety objectives, continuously monitors performance, identifies inadequacies, fosters a healthy safety culture and continually improves that culture. Throughout 2018, CNSC staff reviewed and assessed program performance and key performance indicators through regular compliance verification activities.

For 2018, CNSC staff concluded that the performance of the uranium mines and mills was either satisfactory or fully satisfactory.

Uranium mine and mill licensees in Canada are required to implement and maintain radiation protection programs. Each program must ensure that contamination levels and radiation doses received by individuals are monitored, controlled, maintained below regulatory limits and are kept consistent with the as low as reasonably achievable (ALARA) principal.

For 2018, CNSC staff rated the radiation protection SCA at all five facilities as either satisfactory or fully satisfactory based on regulatory oversight activities. The fully satisfactory rating for McClean Lake is discussed in section 7.2.

Cigar Lake McArthur River Rabbit Lake Key Lake McClean Lake
SA SA SA SA FS
FS = fully satisfactory SA = satisfactory

Sources of radiation exposure at uranium mines and mills include:

CNSC staff’s compliance activities confirmed these hazards were controlled by the licensees’ radiation protection programs, including practices relating to the effective use of time, distance and shielding, source control, ventilation, contamination control and personal protective equipment.

During 2018, CNSC staff conducted regulatory oversight activities for the radiation protection SCA at all five facilities. These activities were carried out to verify that licensees were complying with regulatory requirements for the implementation of radiation protection programs.

Radiation protection programs include codes of practice that outline licensee administrative levels and action levels for exposures and doses of radiation. Administrative levels include a list of specific actions to be taken by the licensee based on radiological monitoring in the workplace. The radiation protection programs include actions to be taken under specific conditions, for example:

• “continue to work while monitoring or investigating a parameter”; or
• “leave the area and initiate an investigation”

As radiation levels or worker exposure levels increase, the required protective actions become more stringent, which is consistent with a risk-informed approach.

Administrative levels are identified for all radiological hazard types, apply to normal operating conditions and are followed to ensure optimal conditions for workers. Licensees are responsible for identifying the parameters of their programs that represent timely indicators of potential losses of control. For this reason, action and administrative levels are licensee-specific and may change over time, depending on operational and radiological conditions. If an action level is reached, it may indicate the loss of control of part of a licensee’s radiation protection program. The licensee is then required to establish the cause, notify the CNSC and if applicable, restore the effectiveness of the radiation protection program.

The five uranium mines and mills have the same individual nuclear energy worker (NEW) radiation dose action level of 1 millisievert (mSv) per week and 5 mSv per quarter of a given year. As a result of two events at the Cigar Lake Operation, seven radiation-related action level exceedances were reported by the licensee in 2018 and are described in appendix H. Figure 2.3 shows a CNSC inspector measuring the gamma dose rate on an ore slurry pipe at the Cigar Lake Operation.

CNSC staff confirmed that during the reporting period, the radiation protection programs and practices at uranium mines and mills remained effective at controlling radiological exposure to workers.

#### Application of ALARA

The radiation protection programs established by uranium mine and mill licensees include responsibilities and processes for ensuring that exposures to workers are consistently ALARA.

Through onsite inspections, CNSC staff verified that key elements of these ALARA programs (e.g., management control over work practices, personnel qualification and training, control of occupational and public exposure to radiation, planning for unusual situations) were effectively implemented by uranium mine and mill facilities in 2018.

This report includes the reporting of annual collective dose values for NEWs for each mine and mill (see sections 3.2, 4.2, 5.2, 6.2 and 7.2). The collective dose value is the sum of the effective doses received by all NEWs at a uranium mine and mill in one year. Collective dose is a radiation protection performance indicator that provides the total exposures associated with each operation. It supplements other performance statistics, like average dose, which have been affected by factors including changes in the number of workers or workers who receive radiation exposures over very short periods of time. Collective dose shows the effect of increased or reduced facility activities, for example, the Rabbit Lake Operation’s transition from actively mining and milling ore to care and maintenance status (figure 5.3) or the ramping-up of production at the McClean Lake Operation (figure 7.3).

#### Worker dose control

In accordance with the Radiation Protection Regulations [4], licensee radiation protection programs include processes and criteria to provide assurance that all individuals identified as NEWs under section 2 of the NSCA [1] are appropriately designated and trained. This includes licensees’ employees and contractors. Radiation exposures are ascertained through approved dosimetry methods and workers are notified of the results.

Figure 2.4 shows a continuous air monitor, alphaNUCLEAR PRISM, used in mine and mill operations to measure radon gas and radon progeny.

Figures 2.5 and 2.6 show the average individual effective dose and maximum individual effective dose during the 2014 to 2018 reporting period for the five facilities. In 2018, no worker at any facility exceeded the regulatory individual effective dose limit of 50 mSv in one year and 100 mSv in a five-year dosimetry period.

Increases and decreases over time in the effective dose to NEWs are explained in the facility-specific sections of this report, in the subsection on worker dose control.

The highest maximum individual effective dose to a worker at a uranium mine or mill in 2018 occurred at the Cigar Lake Operation. A dose of 7.28 mSv was assigned to an underground maintenance worker. This exposure is further discussed in the Cigar Lake section of this report. This value is 14.3 percent of the annual dose limit of 50 mSv.

Appendix G displays the number of NEWs at each facility, with the corresponding average individual effective dose and maximum individual effective dose for each facility from 2014 to 2018.

#### Estimated dose to the public

Uranium mine and mill operations are located in remote areas, away from local populations. The Radiation Protection Regulations [4] set out a public radiation dose limit of 1 mSv per year above natural background radiation to ensure the protection of health and the public.

Radiological exposures measured at the boundaries of these remote licensed facilities are close to measured background radiation levels. As published in the CNSC fact sheet on natural background radiation, the background radiation level for Canada is approximately 1.8 mSv.

In 2018, CNSC staff were satisfied that uranium mine and mill licensees controlled radiation doses to persons at levels well below the regulatory limits and that licensees kept doses ALARA. This conclusion was based on the outcome of inspections, as well as reviews of licensees’ radiation protection programs, radiological hazard control, worker dose control and application of the ALARA principle.

### 2.4 Environmental protection

The environmental protection SCA covers programs that identify, control and monitor releases from facilities of radioactive and hazardous substances and the effects on the environment as a result of licensed activities.

Based on regulatory oversight activities, CNSC staff rated the 2018 performance of all five uranium mine and mill facilities for the environmental protection SCA as satisfactory. CNSC staff concluded the licensees’ environmental protection programs were effectively implemented and met all regulatory requirements.

Environmental protection ratings
Cigar Lake McArthur River Rabbit Lake Key Lake McClean Lake
SA SA SA SA SA
SA = satisfactory

#### 2.4.1 Environmental management system

The CNSC requires licensees to develop and maintain environmental management systems that provide a framework for integrated activities related to environmental protection at the operation. Environmental management systems are described in approved environmental management programs and include activities such as establishing annual environmental objectives, goals and targets. The licensees conduct internal audits of their programs as identified in their CNSC-approved management system program. CNSC staff confirmed the licensees’ objectives, goals and targets through regular compliance verification activities. Facility-specific details are provided in sections 3.3, 4.3, 5.3, 6.3 and 7.3 of this report.

#### 2.4.2 Effluent and emissions control

Effluent and emissions control programs are associated with an environmental code of practice that sets out administrative levels and action levels for select contaminants of potential concern (COPC) with the potential for adverse environmental effects. An administrative level represents the upper range of design specifications for a specific parameter. Reaching an administrative level triggers an internal review by the licensee. Exceedance of an action level indicates a potential loss of control of the environmental protection program, which is based on the approved facility design envelope; it triggers actions that the licensee must take to correct the problem.

This requires notification to the CNSC, an immediate investigation, subsequent corrective actions and preventive measures in order to restore the effectiveness of the environmental protection program. It is important to recognize that an exceedance of an action level does not imply a potential risk to the environment, but identifies that the operating parameter may be outside the facility design envelope. Facility administrative and action levels are determined through the identification and proper operation of existing treatment technologies, as well as facility-specific environmental risk studies.

In 2018, one action level exceedance for radium-226 occurred at McArthur River, and one action level exceedance for total suspended solids (TSS) in treated effluent released to the environment occurred at McClean Lake. More details are provided in the environmental protection sections of this report for McArthur River and McClean Lake.

##### Treated effluent released to the environment

Environmental risk assessments (ERAs) identified releases of molybdenum, selenium and uranium with the potential for adverse environmental effects at uranium mines and mills. As a result, improved engineering controls and treatment technologies to reduce effluent releases of these contaminants were implemented where required. In 2018, the treatment technologies implemented continued to keep these contaminant concentrations stable, below regulatory limits and ALARA. Figures 2.7 to 2.9 show the 2018 average annual effluent concentrations for molybdenum, selenium and uranium at the five mine and mill facilities.

In the absence of federal or provincial effluent discharge limits for molybdenum, the CNSC required licensees to develop facility-specific effluent controls within the codes of practice of their environmental protection programs. The 2014 to 2018 average concentrations of molybdenum in effluent for the five facilities were below the Key Lake code-of-practice action level. The Key Lake action level of 0.6 mg/L for molybdenum is the most stringent of the five operations and is shown in figure 2.7 for reference only.

Figures 2.8 and 2.9 show that both selenium and uranium concentrations in treated effluent released to the environment by mine and mill facilities from 2014 to 2018 remained below Saskatchewan’s licensed effluent maximum monthly mean discharge limits of 0.6 mg/L and 2.5 mg/L for selenium and uranium, respectively. As indicated in figure 2.9, the CNSC identified an interim objective for uranium of 0.1 mg/L. This was derived from the treatment technologies in place at the uranium mines and mills and based on what would be achievable by the uranium metal mining sector. The interim objective was applied to all uranium mine and mill facilities since it was the most stringent and has been consistently met since 2016. The interim objective for uranium in effluent is in place until the CNSC requirements for release limits are published in REGDOC-2.9.2, which is currently undergoing internal CNSC review.

In addition to the above COPCs with the potential for adverse environmental effects, a graph showing concentrations of radium is provided in figure 2.10. From 2014 to 2018, the annual average effluent concentrations of radium-226 for the five facilities were well below the CNSC’s licence-authorized monthly mean effluent discharge limit of 0.37 Bq/L.

Uranium mine and mill facilities also analyze treated effluent for concentrations of other regulated contaminants and COPC such as arsenic, copper, lead, nickel, zinc, total suspended solids (TSS) and pH. Table 2.3 shows the annual average parameter concentration values in effluent for these substances released in 2018, as well as the discharge limits described in the Metal and Diamond Mining Effluent Regulations (MDMER) [5] made under the Fisheries Act [6]. All metal mines and mills in Canada are subject to the MDMER. The CNSC incorporates the effluent limit requirements of the MDMER in uranium mine and mill licences. In 2018, all treated effluent released to the environment from licensed mining and milling activities for the above substances met the effluent discharge limits.

Table 2.3: Annual average parameter concentration values in effluent released to the environment, 2018
Parameters MDMER discharge limits Cigar Lake McArthur River Rabbit Lake Key Lake McClean Lake
Arsenic (mg/L) 0.5 0.0603 0.0009 0.0009 0.0080 0.0300
Copper (mg/L) 0.3 0.0008 0.0010 0.0003 0.0050 0.0030
Lead (mg/L) 0.2 0.0002 0.0009 0.0001 0.0100 0.0028
Nickel (mg/L) 0.5 0.0009 0.0031 0.0015 0.2570 0.0130
Zinc (mg/L) 0.5 0.0271 0.0014 0.0006 0.0090 0.0030
Molybdenum (mg/L) N/A 0.1030 0.0164 0.1800 0.0700 0.0030
Selenium (mg/L) N/A 0.0044 0.0023 0.0026 0.0100 0.0210
TSS (mg/L) 15 1 1 1 2 2
pH annual mean value 6.0–9.5 7.3 7.5 7.3 6.7 7.2

CNSC staff will continue to review effluent quality results to ensure effluent treatment performance remains effective.

##### Treated mining/milling effluent: A comparison of the uranium mining sector to other metal mining sectors across Canada

As noted earlier, metal mines and mills in Canada are subject to the MDMER [5] made under the federal Fisheries Act [6]. Compliance with MDMER limits provides a good comparison of the effluent treatment in the mining sector to other metal mining sectors across Canada. The quality of the effluent treatment at the uranium mine and mill facilities compares favourably to that in other mining sectors of base metal, precious metal and iron mines.

The data used for this comparison are acquired from Environment and Climate Change Canada (ECCC). Figure 2.11 and tables 2.4 and 2.5 provide the sector-specific MDMER [5] information available for 2018 for effluent constituents of molybdenum, selenium and uranium. ECCC effluent quality data for 2017 and 2018 for arsenic, copper, nickel, lead, zinc, pH, TSS and acute lethality testing was not available at the time of writing this report. A comparison of these parameters for the most recent available MDMER data (2016) is presented in the 2017 regulatory oversight report. The 2017 regulatory oversight report concluded that the uranium sector was similar or better than the other three metal mining sectors with regard to the following performance indicators: effluent concentrations, compliance with regulatory limits and toxicity test results.

The mines that released treated effluent reporting under MDMER are grouped into four metal mining sectors based on the primary metal produced. The metal mining sectors are:

• uranium – 5 facilities
• base metals (such as copper, nickel, molybdenum or zinc) – 47 facilities
• precious metals (such as gold or silver) – 56 facilities
• iron – 8 facilities

Molybdenum is a parameter requiring routine monitoring of treated effluent subject to MDMER [5]. Ecological risk assessments completed in the mid-2000s indicated that releases of molybdenum posed a risk to biota that warranted adaptive management. Following a request from the Commission, licensees added administrative controls and treatment technology upgrades to their effluent management systems. The success of these actions is evident in figure 2.11, which shows that molybdenum releases in the uranium mining sector have decreased substantially.

In 2018, molybdenum concentrations in uranium mining effluent were similar to those measured in precious metal and iron mine effluent, and lower than those measured in base metal mine effluent.

In mid-2012, the requirement to monitor selenium was added to the Metal Mines Effluent Regulations (MMER). Table 2.4 summarizes the average selenium concentration in treated effluent from each mining sector using data collected since 2012. The selenium concentration in uranium sector effluent was similar to that of other metal mining sectors in Canada.

Table 2.4: Average selenium concentration in treated effluent by metal mining sector, last half of 2012 and all of 2013-18
Year Metal mining sector
Uranium (mg/L) Base metals (mg/L) Precious metals (mg/L) Iron (mg/L)
2012-13 0.003 0.005 0.005 0.001
2014 0.004 0.006 0.005 0.001
2015 0.004 0.005 0.004 0.004
2016 0.008 0.006 0.003 0.003
2017 0.004 0.008 0.004 0.001
2018 0.006 0.006 0.004 0.003

Uranium concentrations were recently added as a parameter to be monitored and reported under the MDMER [5]. Table 2.5 presents the average uranium concentrations in treated effluent by metal mining sector. As shown in table 2.5, the uranium sector had an average uranium concentration of 0.0119 mg/L in 2018. Uranium mines have elevated natural uranium concentrations compared to other conventional mining operations. For context, the action level in the environmental code of practice is 0.3 mg/L, and the Saskatchewan regulatory limit for uranium is 2.5 mg/L. CNSC staff continue to verify that releases of uranium are controlled and reduced to the extent practicable by reviewing effluent quality data, scrutinizing proposed facility changes that could affect effluent quality and validating the effectiveness of the licensees’ programs to minimize the release of contaminants.

Table 2.5: Average uranium concentration in treated effluent by metal mining sector, 2017-18
Year Metal mining sector
Uranium (mg/L) Base metals (mg/L) Precious metals (mg/L) Iron (mg/L)
2017 0.0185* 0.0062 0.0027 0.0002
2018 0.0119* 0.0027 0.0010 0.0036
* Data not available from Environment and Climate Change Canada; value calculated from licensee annual reports.
##### Uncontrolled releases

Licensees are required to report to the regulatory authorities, including the CNSC, any unauthorized releases (spills) of hazardous or radioactive substances to the environment.

Figure 2.12 shows the number of environmental reportable spills for uranium mine and mill facilities during the 2014–18 reporting period. In each case, CNSC staff reviewed and evaluated the licensee’s actions to ensure effective remediation and prevention, and they were satisfied with actions taken by the licensee. CNSC staff rated all 2018 spills as “low significance” resulting in no residual impact on the environment.

The facility-specific sections and appendix I describe each reportable spill and the licensee’s corrective actions in response to it. The CNSC’s spill rating definitions are also found in appendix I‑2.

##### Air emissions released to the environment

Uranium mines and mills environmental programs include monitoring the effects of operations on the surrounding air and soil. Licensees measure airborne particulate levels and concentrations of regulated contaminants and COPC, as well as the concentration of radon gas in ambient air. Soil and vegetation may be affected by atmospheric deposition of particulate containing adsorbed metals and radionuclides associated with onsite activities. Licensees monitor contaminant concentrations in soil and terrestrial vegetation to verify that operational impacts are below regulatory limits and ALARA.

Facilities with milling operations monitor atmospheric emissions from acid plants, yellowcake dryers, calciner operations, packaging, grinding and ammonium sulphate operations. Other measured parameters (e.g., ambient radon and stack testing for sulphur dioxide, uranium and heavy metals) verify facility design and evaluate the operation’s performance against predictions made in ERAs.

CNSC staff verified that the mines and mills demonstrated satisfactory performance mitigating and monitoring the effects of their operations on the surrounding air and soil. Soil monitoring results around the facilities indicated that all measured parameters come within the background level. As would be expected, air monitoring for radon gas near tailings management facilities and waste rock piles shows results higher than the regional background level of 25 Bq/m3. For example, at Rabbit Lake, for the last six years, radon concentrations at a B-Zone sampling location ranged from 37 Bq/m3 to 62.9 Bq/m3. However, the concentrations fell to background levels within a short distance – less than two kilometres from the facility. The monitoring results indicate negligible impacts to the environment from atmospheric releases and confirm that all uranium mines and mills are in compliance with their environmental programs and provincial standards.

#### 2.4.3 Assessment and monitoring

In accordance with the Uranium Mines and Mills Regulations [7], each uranium mine and mill licensee has an environmental monitoring program that monitors concentrations of nuclear and hazardous substances in the environment, and characterizes and monitors effects to the environment associated with the licensed facility. Nuclear and hazardous substances associated with monitoring programs are selected based on regulated COPCs identified through the licensee’s ERA. COPCs identified through the ERA that have the potential for adverse environmental effects are managed through increased monitoring, inclusion in the environmental code of practice and further study or implementation of additional controls by licensees. CNSC staff review and evaluate environmental monitoring programs as criteria for assessing environmental performance.

The results of the licensee’s environmental monitoring programs relative to the ERA predictions are provided in an environmental protection report (EPR) that is typically completed every five years and provides environmental data collected over the previous five-year period. CNSC staff and the Saskatchewan Ministry of Environment staff review the EPRs once these reports are released.

#### 2.4.4 Environmental risk assessment

The CNSC uses facility-specific environmental risk assessments (ERAs) developed by licensees as a regulatory tool throughout the lifecycle of uranium mine and mill facilities. Applicants use ERAs during initial environmental assessments for new facilities and for changes to existing facilities or activities at licensed operations where applicable. The ERA identifies the need for mitigation technologies or practices and predicts:

• physical disturbances
• releases to the atmosphere
• releases to surface water
• air quality
• soil and sediment quality
• surface water quality
• groundwater quality
• changes to the physical environment
• biological and human health effects

The results of the licensee’s effluent and environmental monitoring programs relative to the ERA predictions are provided in an environmental protection report that is typically completed every five years. The CNSC and the Saskatchewan Ministry of Environment staff review licensees’ monitoring program results on a regular basis and the environmental protection report(s) when released.

If required, ERAs are updated and the risks to the public and the environment are reassessed every five years. ERAs are updated based on changes to operational activities, revised predictions, environmental monitoring data collected over the previous five years and the latest science. Table 2.6 shows the year of the most recent ERA submitted for each uranium mine and mill and the year the next ERA updates will be submitted to the CNSC for review. CNSC staff regularly review ERAs to determine the potential risks to human health and the environment and to verify that mitigation measures are adequate.

Cigar Lake McArthur River Rabbit Lake Key Lake McClean Lake 2017 2015 2015 2015 2016 2022 2020 2020 2020 2021

#### 2.4.5 Protection of the public

According to regulatory requirements, each licensee must demonstrate that the public is protected from exposures to radiological and hazardous substances released from an operation. Protection of the public is assessed in the ERA, which contains a human health risk assessment (HHRA). The HHRA assesses hazardous and radiological releases from facilities, and it models the resultant concentrations of contaminants in air, water, soil and traditional foods (such as fish, waterfowl and moose). The concentrations of contaminants consumed by a typical local resident are assessed against human health benchmarks in the HHRA. For all facilities, the HHRAs confirmed that the concentrations of contaminants for a typical local resident are well below concentrations that could cause health effects. Therefore, it has been determined that the health of persons in areas surrounding the facilities is protected.

##### Eastern Athabasca Regional Monitoring Program

The Eastern Athabasca Regional Monitoring Program (EARMP) is a well-recognized environmental monitoring program designed to gather data on long-range environmental information and potential cumulative impacts downstream from uranium mining and milling operations. The program was initiated in 2011 with funding from the Saskatchewan government and the uranium mining industry (Cameco and Orano) as a sub-element of the Province of Saskatchewan's Boreal Watershed Initiative, which ended in 2017. The CNSC became a funding partner in 2017–18 to support the publication of an EARMP final report (2011 to 2017) with a five-year long-term funding agreement (2018–19 to 2022–23) signed in 2018 between the Saskatchewan Government, the CNSC and industry. The community program monitors the safety of traditionally harvested country foods by analyzing water, fish, berries and wild meat (e.g., grouse, rabbit, caribou and moose) from representative northern Saskatchewan communities. The program contractor is an Indigenous-owned business in northern Saskatchewan. Samples are collected from areas identified by community members, with members either assisting in sample collection or providing samples from their own harvesting activities.

Harvesting and consuming traditional country foods are an important part of the culture in northern Saskatchewan. The intent of EARMP is to provide confidence and transparent communication with community members that traditional country foods remain safe to eat today and for future generations. The program has demonstrated that concentrations of chemicals of interest have been relatively consistent over time and generally within the regional reference range indicating no evidence of long-range transport of contaminants associated with uranium mining.

Evaluation of country food data from previous years confirmed uranium mines and mills are not affecting the safety of country foods at nearby communities. The results indicated that radiological and non-radiological exposures to residents consuming country foods were similar to exposures of the general Canadian population. The EARMP has proven to be a productive means of involving the community in monitoring the health of their local environment and provided them with confidence in the safety of their traditional foods. The conclusion of the EARMP is that water and country foods are considered safe for consumption.

The annual reports and data are available at earmp.ca. The CNSC continues to support the EARMP and CNSC staff are working to further collaborate on this valuable program.

### 2.5 Conventional health and safety

The conventional health and safety SCA covers the implementation of a program to manage workplace safety hazards and protect personnel and equipment. Uranium mines and mills must develop, implement and maintain effective safety programs to promote safe and healthy workplaces and to minimize occupational injuries and illnesses.

For 2018, CNSC staff rated the conventional health and safety SCA at uranium mine and mill facilities as satisfactory, following acceptable performance in health and safety practices, awareness and performance.

Conventional health and safety ratings
Cigar Lake McArthur River Rabbit Lake Key Lake McClean Lake
SA SA SA SA SA
SA = satisfactory

#### Practices

The CNSC requires licensees to identify potential safety hazards, assess associated risks, and introduce the necessary materials, equipment, programs and procedures to effectively manage, control and minimize these risks. CNSC staff work in collaboration with the Saskatchewan Ministry of Labour Relations and Workplace Safety to provide regulatory oversight of conventional health and safety in uranium mines and mills. CNSC staff’s compliance verification activities include inspections, reviews of compliance reports and health and safety events.

CNSC staff confirmed that licensees at uranium mines and mills implemented effective managed conventional health and safety in their activities. In addition to CNSC staff’s regulatory oversight, the Saskatchewan Government conducts regular inspections of occupational health and safety, mine safety and fire protection through an agreement with the Government of Canada.

#### Awareness

CNSC staff observed how the implementation of conventional health and safety programs continued to provide workers with education, training, tools and support (see figure 2.13). Each facility licensee promotes the idea that safety is the responsibility of all individuals; this message is reinforced by the licensees’ management, supervisors and workers. The licensees’ management members stress the importance of conventional health and safety through regular communication, management oversight and the continual improvement of safety systems. Through onsite inspections, CNSC staff have identified a high level of communication and awareness in the area of conventional health and safety. CNSC staff concluded that in 2018, licensees of uranium mines and mills were committed to accident prevention and safety awareness, and focused on safety culture.

#### Performance

Key performance measurement criteria for conventional health and safety are the number of lost-time injuries (LTIs) and the total recordable incident rate (TRIR) that occur at each facility. An LTI is a workplace injury that results in the worker being unable to return to work for a period of time. In reviewing each LTI, CNSC staff consider injury severity and frequency rates. The TRIR is the incident frequency rate, measuring the number of fatalities, lost-time injuries and other injuries requiring medical treatment. Table 2.7 shows the number of LTIs at the uranium mines and mills, along with severity, frequency and TRIRs.

Cigar Lake McArthur River Rabbit Lake Key Lake McClean Lake 0 0 0 0 1 0 23.2 0 0 4.8 0 0 0 0 0.3 1.0 5.02 5.03 2.59 0.75 1 An injury that takes place at work and results in the worker being unable to return to work for a period of time. 2 A measure of the total number of days lost to injury for every 200,000 person-hours worked at the facility. Accident severity rate = [(# of days lost in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 3 A measure of the number of LTIs for every 200,000 person-hours worked at the facility. Accident frequency rate = [(# of injuries in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 4 A measure of the number of fatalities, lost-time injuries and other injuries requiring medical treatment for every 200,000 person-hours worked at the facility. Recordable incident rate = [(# of incidents in last 12 months) / (# of hours worked in last 12 months)] x 200,000.

Appendix K provides additional details on 2018 LTIs at the McClean Lake Operation and the corrective actions taken. Information about these events can be found in section 7.4. CNSC staff and the Saskatchewan Ministry of Labour Relations and Workplace Safety monitor and review each reportable injury to ensure the cause is identified and the corrective actions taken are satisfactory. When applicable, injury information is shared among the facilities for lessons learned to improve safety and prevent reoccurrences.

CNSC staff concluded through their compliance verification activities that the health and safety programs at all uranium mines and mills met regulatory requirements in 2018.

#### Lost-time injuries: Comparison of the uranium mining sector to other mining sectors in Saskatchewan

Table 2.8 displays the various safety statistics concerning mining sectors within Saskatchewan. When contractors are excluded, the uranium mining and milling sector exhibits performance similar to other mining sectors for LTIs and frequency rate. The uranium sector comparison excludes contractors because statistics for the other sectors do not include contractors.

Table 2.8: Safety statistics for mining sectors in Saskatchewan, 2018
Mining sector Number of lost-time injuries* Accident frequency rate (200,000 person-hours)* Accident severity rate (200,000 person-hours)* Total recordable incident rate (200,000 person-hours)***
Potash (underground) 4 0.1 6.8 1.3
Solution (potash) 3 0.4 5.8 0.77
Minerals (sodium sulphate, sodium chloride) 2 0.7 2.5 _ _
Hard rock (gold, diamond) 10 0.8 31.1 3.62
Coal (strip mining) 6 1.1 38.4 2.10
Uranium 1 0.08 8.5 1.74
Uranium (including contractors)** 1 0.06 14.0 2.74****

* Source: Saskatchewan Ministry of Labour Relations and Workplace Safety.

** Statistics for all the other mining sectors do not include contractors.

*** Source: Saskatchewan Mining Association, data provided voluntarily by member companies.

**** Source: See tables 3.3, 4.3, 5.4, 6.3 and 7.3 for the data for each individual licenced uranium operation.

CNSC staff benchmarked the injury frequency rate at Saskatchewan uranium mines and mills with national and international mining statistics. One limitation to consider when comparing safety-related statistics is the variation in definitions of a workplace injury. However, efforts are made where possible to compare and assess licensee performance against relevant national and international benchmarks. Table 2.9 shows various international benchmarks related to workplace incident frequency rates. The performance of the uranium mining and milling sector in Canada is similar.

Table 2.9: National and international benchmarking for workplace safety
Publication/standard Lost-time frequency rate Total recordable incident rate Notes
Government of Western Australia Department of Mines, Industry Regulation and Safety1 2.3, 3.1 N/A 2.3 across all mining sectors and 3.1 in non-metal mining environments; rates are per million hours worked for 2016–17
International Council on Mining and Metals2 4.3 N/A Average rates are per million hours worked for 2016 based on statistics from 27 of the largest international mining companies
2017 Workplace Fatality and Injury Rate Report – Canada3 1.9 N/A Average rate across all Canadian provinces and territories per million hours worked
The National Institute for Occupational Safety and Health4 (U.S.) 1.7 N/A Average rate per 200,000 hours worked in 2015
International Council on Mining and Metals (ICMM)5 N/A 3.94 Total recordable injury frequency rate for ICMM members. Rate per 200,000 hours worked in 2017
International Council on Mining and Metals (ICMM)5 N/A 4.26 Total recordable injury frequency rate for ICMM members. Rate per 200,000 hours worked in 2016
International Council on Mining and Metals (ICMM)5 N/A 4.70 Total recordable injury frequency rate for ICMM members. Rate per 200,000 hours worked in 2015

1 Safety performance in the Western Australian mineral industry for 2016–17, Government of Western Australia, Department of Mines, Industry Regulations and Safety, 2018.

2. Benchmarking 2016 safety data: progress of ICMM members, International Council on Mining and Metals.

3 2017 Workplace Fatality and Injury Rate, Tucker. S, University of Regina, 2017.

4 Number and rate of mining non-fatal lost-time injuries by year, 2006–15, National Institute for Occupational Safety and Health.

5 Benchmarking 2017 safety data: progress of ICMM members, International Council on Mining and Minerals.

N/A not available

## 3. Cigar Lake Operation

Cameco Corporation is the operator of the Cigar Lake Operation, which is located approximately 660 kilometres north of Saskatoon, Saskatchewan.

The Cigar Lake Operation consists of an underground uranium mine with surface facilities for loading ore slurry into trucks, waste management facilities, a water treatment plant, surface freeze plants, administration offices and warehouses. Figure 3.1 shows an aerial view of the Cigar Lake Operation.

Table 3.1 presents the mining production data from 2014 to 2018. Commercial production commenced at the Cigar Lake mine in the spring of 2014.

2014 2015 2016 2017 2018 3.32 26.1 37.27 36.49 43.06 6.02 22.92 18.27 18.85 16.1 0.2 4.95 6.81 6.88 6.94 9.25 9.25 9.25 9.25 9.25 *Mining up to 7.0 million kg of uranium per year, with a production flexibility up to 9.25 million kg of uranium

CNSC staff confirmed the Cigar Lake Operation production remained within the authorized CNSC licence limit for the 2018 calendar year and is carrying forward a cumulative production shortfall of 12.7 million kilograms of uranium. This shortfall can be recouped in future years by increasing production.

Construction activities in 2018 focused on completing and maintaining infrastructure to sustain production, which included commissioning the brine system to freeze the ground around the ore body and waste rock handling facilities.

### 3.1 Performance

The safety and control area (SCA) ratings at Cigar Lake for the five‑year period from 2014 to 2018 are shown in appendix E. For 2018, CNSC staff rated all 14 SCAs for the Cigar Lake Operation satisfactory.

In 2018, CNSC staff carried out SCA compliance inspections covering waste management, management system, radiation protection, environmental protection, conventional health and safety, packaging and transport, and fitness for service. Eight non-compliance were identified through CNSC inspections at the Cigar Lake Operation for the 2018 calendar year. These non-compliance items were of low risk and related to the management system, radiation protection, packaging and transport, and environmental protection SCAs. Corrective actions were implemented by the licensee, then reviewed and accepted by CNSC staff. A complete list of these inspections, including the dates the reports were sent to licensees and SCAs assessed, can be found in appendix B.

This report focuses on the three SCAs that cover many of the key performance indicators for these mines and mills: radiation protection, environmental protection, and conventional health and safety.

For 2018, CNSC staff continued to rate the radiation protection SCA at Cigar Lake as “satisfactory” based on regulatory oversight activities.

Cigar Lake Operation – radiation protection ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

The main source of radiological exposure at the Cigar Lake Operation is from mining high-grade uranium ore. The effective dose contributors to nuclear energy workers (NEWs) at Cigar Lake remained similar to previous years, with gamma radiation (40%), radon progeny (34%) and long-lived radioactive dust (LLRD) (26%). Gamma radiation hazards are controlled through the effective use of time, distance and shielding. Exposures to radon progeny and LLRD are controlled through source control, ventilation, contamination control and personal protective equipment.

CNSC staff confirmed that the radiation protection program and practices at the Cigar Lake Operation remained effective in controlling radiological exposure to workers. Two events resulted in employees exceeding either weekly or quarterly action levels. In June 2018, four workers exceeded the weekly action level of 1 mSv, and one also exceeded the quarterly action level of 5 mSv. In November 2018, one worker exceed both the weekly action level and quarterly action level. As a result of these two events, CNSC staff conducted a focused inspection of the Radiation Protection Program and specific components of the Management System Program at Cigar Lake. CNSC staff verified that Cameco follows approved programs and that, with the experience of the 2018 incidents, these programs were improved and continued to protect workers.

#### Application of ALARA

In 2018, the collective radiation exposure to NEWs at the Cigar Lake Operation was
387 person-millisieverts (p-mSv), an approximate 2.8-percent increase from the 2017 value of 376 p‑mSv, but below the average value of 451 p-mSv for the past four years (see figure 3.2).

Efforts to keep worker exposures as low as reasonably achievable (ALARA) included the ongoing assessment of activities and areas with higher levels of risk for radon progeny exposures, such as jet-boring system operators. While the assessments have demonstrated that the procedural controls in place are effective, engineering improvements were applied to reduce or eliminate the risk of exposure to elevated levels of radon progeny. This target was modified in 2018 to focus on the top five workers for the facility and look for opportunities to reduce their exposures. In addition, Cameco is investigating new direct reading dosimeters and developing prototype PRISM units to monitor radon progeny. CNSC staff concluded that the Cigar Lake Radiation Protection Program remained effective at ensuring that worker exposures remain consistently ALARA.

#### Worker dose control

During 2018, the average individual effective dose to NEWs was 0.47 millisieverts (mSv), compared to the average effective dose of 0.34 mSv in 2017. The slight increase in the average dose is attributed to a significant reduction in the number of workers (824 in 2018 vs. 1,107 in 2017) and maintenance activities, and it is of low regulatory significance.

The increase in the maximum dose from 3.36 mSv in 2017 to 7.28 mSv in 2018 is attributed to an event which occurred in late 2018. A significant portion of the worker’s annual dose (about 60%) was due to an exposure to elevated levels of radon progeny from this event. As indicated in figures 2.5 and 2.6, no worker exceeded the regulatory individual effective dose limit of 50 mSv in one year and 100 mSv in a five-year dosimetry period. CNSC staff verified that improvements have been made at Cigar Lake Operation to provide a higher level of assurance that radiological hazards are anticipated and that assumptions about the absence of hazard are verified through suitable radiological monitoring by Cameco.

Based on compliance verification activities that included inspections, reviews of licensees’ reports, work practices, monitoring results and individual effective dose results for 2018, CNSC staff were satisfied that the Cigar Lake Operation continued to be effective at controlling radiation doses to workers.

### 3.3 Environmental protection

For 2018, CNSC staff continued to rate the environmental protection SCA as satisfactory. CNSC staff concluded that the licensee’s environmental protection program was effectively implemented and met all regulatory requirements.

Cigar Lake Operation – environmental protection ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

#### Environmental management system

The environmental management system at the Cigar Lake Operation includes activities such as establishing annual environmental objectives, goals and targets. Cameco conducts internal audits of its environmental management program at the Cigar Lake Operation, as identified in the CNSC-approved management system program. CNSC staff reviewed and assessed the objectives, goals and targets through regular compliance verification activities. CNSC staff confirmed that Cameco had continued to conduct routine inspections, internal audits, environmental training and periodic reviews of environmental monitoring data. These activities were conducted to ensure continual improvement and to confirm that the controls put in place to protect the environment are effective.

#### Effluent and emissions control

##### Treated effluent released to the environment

CNSC staff confirmed that parameter concentrations in treated effluent were low and remained below treated-effluent discharge limits at the Cigar Lake Operation. CNSC staff verified that treated effluent released to the environment was well below regulatory requirements. At the Cigar Lake Operation throughout 2018, concentrations for molybdenum, selenium and uranium (shown in figures 2.7 to 2.9) remained below their respective action levels and well below provincial licence effluent discharge limits.

The Cigar Lake Operation is required to monitor concentrations of other regulatory contaminants and COPCs, such as radium-226, arsenic, copper, lead, nickel, zinc, total suspended solids (TSS) and pH. CNSC staff reviewed the Cigar Lake Operation and confirmed that it continued to meet Metal and Diamond Mining Effluent Regulations (MDMER) [5] discharge limits (shown in section 2.4). There were no exceedances of the action levels in the environmental code of practice.

In 2016, the Cigar Lake Operation EPR identified an increasing arsenic trend in effluent. While below regulatory limits, arsenic concentrations in the treated effluent were above environmental assessment predictions and above concentrations previously measured in the effluent prior to achieving full ore production. In response, Cameco created a working group to identify the causes of the elevated concentration and develop mitigation strategies. In 2018, Cameco implemented several mitigation techniques to reduce arsenic loadings to the environment, such as improving the recycling of process water captured onsite for use in underground processes. As a result, arsenic loadings and mean concentrations decreased to 0.060 mg/L in 2018 compared to 0.075 mg/L in 2017 at Cigar Lake. CNSC staff are satisfied that Cameco is taking appropriate actions to lower arsenic concentrations in the effluent, and they will continue to follow up throughout 2019.

CNSC staff will continue to review effluent quality results to ensure that effluent treatment performance remains effective.

##### Air emissions released to the environment

As required by the CNSC, the Cigar Lake Operation maintains an air and terrestrial monitoring program. Air monitoring at the Cigar Lake facility includes ambient radon, total suspended particulate (TSP), soil sampling and lichen sampling to assess the impact of air emissions. Lichen samples are analyzed to determine the level of airborne particulate contaminants deposited on the surface of the lichen as a means of estimating the level of contamination, if any, entering lichen consumers, such as caribou.

Radon in ambient air is measured using passive track etch cups at eight monitoring stations around the operation. The background concentration of radon in northern Saskatchewan ranges from less than 7.4 Bq/m3 to 25 Bq/m3.

Figure 3.3 illustrates the average concentrations of radon in the air at the Cigar Lake Operation from 2014 to 2018, and shows that measured values are similar to values measured as northern Saskatchewan regional background. The average radon concentrations are less than the reference level of 55 Bq/m3, which represents an incremental dose of 1 mSv per year over background. CNSC staff noted that concentrations remained well below the reference level.

A high-volume air sampler was used to collect and measure TSP in air. Results showed that the TSP levels were lower than provincial standards (see table 3.2). The mean concentrations of metal and radionuclides adsorbed to TSP were low and below the reference annual air quality levels identified in table 3.2.

Soil and terrestrial vegetation may be affected by the atmospheric deposition of particulate, adsorbed metals and radionuclides associated with onsite activities. Lichen and soil samples were collected in 2016 as required under the triennial sampling program. COPC concentrations measured in the soil samples collected from the study area were comparable to historical results. Concentrations of metals remained below existing Canadian Environmental Quality Guidelines [8] set by the Canadian Council of Ministers of the Environment, and radionuclide concentrations were low and near or at background levels and analytical detection limits. CNSC staff concluded that the level of airborne particulate contaminants produced by the Cigar Lake Operation is acceptable and does not pose a risk to the environment.

Table 3.2: Cigar Lake Operation concentrations of metal and radionuclides in air, 2014–18*
Parameter Reference annual air quality levels 2014 2015 2016 2017 2018
TSP (µg/m3) 60 (3) 24.7 15.8 11.4 12.9 18.9
As (µg/m3) 0.06 (1) 0.00025 0.00031 0.0003 0.00039 0.00023
Mo (µg/m3) 23 (1) 0.0001 0.0001 0.0002 0.0002 0.0003
Ni (µg/m3) 0.04 (1) 0.00067 0.00062 0.00105 0.00103 0.00083
Pb (µg/m3) 0.10 (1) 0.0013 0.0009 0.0009 0.0008 0.0008
Se (µg/m3) 1.9 (1) 0.00003 0.00003 0.00003 0.00005 0.00003
Pb-210 (Bq/m3) 0.021 (2) 0.00025 0.000315 0.000305 0.00036 0.00037
Po-210 (Bq/m3) 0.028 (2) 0.000086 0.000095 0.000099 0.00012 0.00013
Ra-226 (Bq/m3) 0.013 (2) 0.000008 0.000014 0.000020 0.000030 0.000026
Th-230 (Bq/m3) 0.0085 (2) 0.00001 0.000014 0.000012 0.000023 0.000018
U (µg/m3) 0.06 (1) 0.00008 0.00055 0.00113 0.00151 0.00103

1 Reference annual air quality levels are derived from Ontario’s 24-hour ambient air quality criteria (2012).

2 Reference level is derived from International Commission on Radiological Protection (ICRP) Publication 96, Protecting People Against Radiation Exposure in the Event of a Radiological Attack.

3 Saskatchewan Environmental Quality Guidelines, Table 20: Saskatchewan Ambient Air Quality Standards. Values are calculated as geometric means.

* Reference levels based on Province of Ontario Ambient Air Quality Criteria and are shown for reference only.
No federal or Saskatchewan provincial limits were established at the time of this report.

The lichen chemistry results from exposure stations in 2016 were similar to those of the reference stations and historic data. CNSC staff concluded that the level of airborne particulate contaminants was acceptable and did not pose a risk to lichen consumers.

#### Uncontrolled releases

In 2018, five events reported to CNSC staff were submitted as releases of hazardous substances to the environment. All five spills listed below were of low significance, and the reporting of these events met the requirements of REGDOC-3.2.1, Public Information and Disclosure [2]:

• On January 24, 2018, a decreasing trend in the level of treated effluent in monitoring pond "D" was observed. It was determined that approximately 1,200 m3 of treated effluent had been released into the ground through a tear in the liner.
• On February 26, 2018, a purge valve on the condenser of Freeze Plant No.2 was leaking. Approximately 100 millilitres of anhydrous ammonia was released to the snow outside the plant.
• On April 12, 2018 a purge point on solenoid valve No.4 at condenser No.2 of Freeze Plant No. 1 was leaking ammonia; 9.2 kilograms of ammonia was released into the plant. It was determined that the probable cause of this leak was a worn teflon seal in the solenoid valve.
• On June 22, 2018, primary freeze plant No.2 was being restarted when ammonia was found to be leaking from a flanged connection to a knife gate valve located above the heat exchanger. No more than 40 kilograms of ammonia were released to the air inside the plant.
• On September 9, 2018, primary freeze plant No.2 was being restarted. Ammonia was identified to be leaking from a knife gate valve used to isolate heat exchangers in the plant. Approximately 0.1 kilograms of ammonia were released to the air inside the plant.

The ammonia release events were attributed to the failure of various mechanisms related to the ground freezing operation. There were no residual impacts to the environment as a result of releases of hazardous substance at the Cigar Lake Operation during 2018. CNSC staff were satisfied with the licensee’s reporting of these spills and the corrective actions taken. CNSC staff rated all 2018 spills as low significance in accordance with the definitions provided in appendix I, table I-2. Figure 2.12 in section 2 displays the number of environmental reportable spills at the Cigar Lake Operation from 2014 to 2018.

Appendix I contains a brief description of the spills, the corrective actions taken by the licensee, CNSC staff’s assessment of those actions and the significance ratings for 2018.

#### Assessment and monitoring

CNSC staff confirmed that the licensee, in accordance with the Cigar Lake environmental protection program, successfully carried out the required environmental monitoring.

Through the compliance verification activities conducted and the review of annual reports and EPRs, CNSC staff concluded that the environmental monitoring conducted at the Cigar Lake Operation met regulatory requirements. Consequently, CNSC staff concluded that the environment remained protected.

#### Environmental risk assessment

The CNSC uses environmental risk assessments (ERAs) to ensure people and the environment are protected. With the exception of arsenic, the Cigar Lake ERA 2017 submission indicated that contaminant levels in the receiving water and sediment were within the predictions made in the 2011 environmental assessment. Although arsenic levels in Seru Bay of Waterbury Lake were above ERA predictions, they remain below the Saskatchewan Surface Water Quality Objectives of 5 µg/L. Cameco implemented measures to address arsenic in the effluent as noted above, and CNSC staff verified that arsenic loading to the environment has decreased steadily since 2016.

The Cigar Lake EPR and updated ERA for the period from 2011 to 2015 were submitted to CNSC in 2016 and to the Saskatchewan Ministry of the Environment in 2017. CNSC staff reviewed the environmental monitoring results for air, soil, vegetation, water, groundwater, sediment and aquatic health indicators and confirmed that the results were within those predicted in the ERA.

After reviewing the EPR and ERA, CNSC staff concluded that adequate measures have been taken at the Cigar Lake Operation to protect the environment.

#### Protection of the public

Cameco is required to demonstrate that the health and safety of the public are protected from exposures to hazardous substances released from the Cigar Lake Operation. The effluent and environmental monitoring programs currently conducted by the licensee are used to verify that releases of hazardous substances do not result in environmental concentrations that may affect public health.

The CNSC receives reports of discharges to the environment through the reporting requirements outlined in the licence and licence conditions handbook. The review of Cigar Lake Operation’s hazardous (non-radiological) discharges to the environment indicates that the public and the environment are protected. CNSC staff confirmed that environmental concentrations in the vicinity of the Cigar Lake Operation remained within those predicted in the 2017 ERA, and that human health remained protected.

Based on compliance verification activities that included inspections, reviews of licensees’ reports, work practices and monitoring results for 2018, CNSC staff concluded that the Cigar Lake Operation’s environmental protection program continued to be effective at protecting the public and the environment.

### 3.4 Conventional health and safety

For 2018, CNSC staff continued to rate the conventional health and safety SCA as satisfactory.

Cigar Lake Operation – conventional health and safety ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

#### Practices

CNSC staff monitored the implementation of the Cigar Lake Operation’s safety and health management program to ensure the protection of workers. The program includes planned internal inspections, a safety permit system, occupational health committees, training and incident investigations. Cameco’s incident reporting system includes reporting, trending and investigation of near misses, which helps reduce future incidents that could cause injury.

CNSC staff noted the implementation of the Safety Through Empowering Employee Leadership Committee. This safety steering committee is unique to the Cigar Lake Operation along with the Good Catch reporting environment in which facility staff are recognized for pointing out near misses related to safety. These were found to be safety culture strengths at the Cigar Lake Operation.

CNSC staff verified that the conventional health and safety work practices and conditions at the Cigar Lake Operation continued to be effective in 2018.

#### Performance

Table 3.3 summarizes lost-time injuries (LTIs) at the Cigar Lake Operation from 2014 to 2018. There were no LTIs at the Cigar Lake Operation in 2018.

Included in this report is the total recordable incident rate (TRIR). The TRIR is the incident frequency rate that measures the number of fatalities, lost-time injuries and other injuries requiring medical treatment, per 200,000 person-hours worked.

2014 2015 2016 2017 2018 1* 4 1 0 0 0.0 18.0 2.4 0 0 0.12* 0.56 0.14 0 0 --- --- 2.0 1.58 1.00 1 An injury that takes place at work and results in the worker being unable to return to work for a period of time. 2 A measure of the total number of days lost to injury for every 200,000 person-hours worked at the facility. Accident severity rate = [(# of days lost in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 3 A measure of the number of LTIs for every 200,000 person-hours worked at the facility. Accident frequency rate = [(# of injuries in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 4 A measure of the number of fatalities, lost-time injuries and other injuries requiring medical treatment for every 200,000 person-hours worked at the facility. Recordable incident rate = [(# of incidents in last 12 months) / # of hours worked in last 12 months)] x 200,000. * One event that occurred in 2014 was reclassified as an LTI in 2015. In the 2014 report, this number was 0.

#### Awareness

CNSC staff observed that the conventional health and safety program at the Cigar Lake Operation continued to provide education, training, tools and support to workers. CNSC staff confirmed that in 2018, Cameco implemented several initiatives as part of continuous program improvement at the Cigar Lake Operation. Changes implemented were to the safety program, including a Cameco-wide development of an ammonia code of practice. CNSC staff confirmed that conventional health and safety events at the operation were investigated and that effective corrective actions were implemented.

CNSC staff compliance verification activities concluded that the Cigar Lake Operation’s health and safety program met regulatory requirements in 2018.

## 4. McArthur River Operation

Cameco Corporation operates the McArthur River mine which is located approximately 620 kilometres north of Saskatoon, Saskatchewan.

Facilities at the McArthur River Operation include an underground uranium mine, primary ore processing, ore slurry loading, waste management facilities, a water treatment plant, effluent storage ponds, surface freeze plants, administration offices and warehouse buildings (see figure 4.1).

High-grade uranium ore is mined, mixed with water and ground in a ball mill to form slurry and pumped to the surface. The ore slurry is loaded into containers and transported to Cameco’s Key Lake Operation for further processing.

Low-grade mineralized rock is also transported to the Key Lake facility in covered haul trucks. These materials are then blended with high-grade ore slurry to create the mill ore feed.

In October 2013, following a public hearing in La Ronge, Saskatchewan, the Commission issued a 10-year licence to Cameco for the McArthur River Operation. Cameco’s licence expires on October 31, 2023.

CNSC staff confirmed that the production for 2018 at McArthur River Operation remained less than the authorized annual production. Mining production data for the McArthur River Operation is provided in table 4.1.

Table 4.1: McArthur River Operation mining production data, 2014–18
Mining 2014 2015 2016 2017 2018
Ore tonnage (Mkg/year) 108.39 88.24 89.28 91.44 2.79
Average ore grade mined (%U) 7.4 8.59 7.89 7.09 7.57
Uranium mined (Mkg U/year) 8.02 7.58 7.04 6.48 0.18
Authorized annual production (Mkg U/year) 8.1 9.6 9.6 9.6 9.6

### 4.1 Performance

The McArthur River Operation safety and control area (SCA) ratings for the five-year period from 2014 to 2018 are shown in appendix E. For 2018, CNSC staff rated all SCAs as satisfactory. This report focuses on the three SCAs that cover many of the key performance indicators for mining operations: radiation protection, environmental protection, and conventional health and safety.

In 2018, CNSC staff carried out compliance inspections for the following SCAs: fitness for service, environmental protection, conventional health and safety, human performance management, physical design, and emergency management and fire protection.

There were five instances of non-compliance identified during CNSC inspections at the McArthur River Operation in 2018. These instances of non-compliance were of low risk and related to the human performance management and the emergency management and fire protection SCAs. The licensee implemented corrective actions, which were reviewed and accepted by CNSC staff. A complete list of inspections can be found in appendix B.

For 2018, CNSC staff continued to rate the radiation protection SCA as satisfactory, based on regulatory oversight activities.

McArthur River Operation – radiation protection ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

Mining of high-grade uranium ore is the main source of radiological exposure at the McArthur River Operation. The effective dose contributors to nuclear energy workers (NEWs) at the McArthur River facility were radon progeny (63%), gamma radiation (22%) and long-lived radioactive dust (LLRD) (15%). Gamma radiation hazards are controlled through practices that involve the effective use of time, distance and shielding. Exposures to radon progeny, radon gas and LLRD are managed through source control, ventilation, contamination control and personal protective equipment.

In 2018, CNSC staff were satisfied that the radiation protection program and practices at the McArthur River Operation remained effective at controlling radiological exposure to workers. The doses to workers remained below regulatory limits and ALARA. There were no exceedances of action levels at the McArthur River Operation in 2018.

#### Application of ALARA

In 2018, the collective dose to NEWs at the McArthur River Operation was 89 person-millisieverts (p‑mSv), a reduction of approximately 88 percent from the 2017 value of 760 p‑mSv (see figure 4.2). The reduction in the collective dose was due to the fact that the facility was placed in a state of care and maintenance.

LLRD exposures remain an ALARA focus area at the McArthur River Operation; these exposures have continued to trend downward in the past five years. The decrease in LLRD exposures in 2018 is attributed primarily to the fact that the facility was placed in a state of care and maintenance.

#### Worker dose control

The average individual effective dose to NEWs was 0.15 mSv. The maximum individual effective dose of 2.67 mSv was assigned to an underground worker. This compares to an average effective dose of 0.79 mSv and a maximum individual dose of 5.73 mSv in 2018. All individual effective doses were well below the annual regulatory limit of 50 mSv (as indicated in figures 2.5 and 2.6) and 100 mSv over five years.

Based on their compliance verification activities, such as inspections, reviews of licensees’ reports, work practices, monitoring results and individual effective dose results, CNSC staff were satisfied that the radiation doses to workers continued to be effectively controlled at the McArthur River Operation during 2018.

### 4.3 Environmental protection

For 2018, CNSC staff continued to rate the environmental protection SCA as satisfactory based on regulatory oversight activities. CNSC staff verified that the environmental protection program was effectively implemented and met all regulatory requirements.

McArthur River Operation – environmental protection ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

#### Environmental management system

The environmental management system at the McArthur River Operation includes activities such as establishing annual environmental objectives, goals and targets. Cameco conducts internal audits of its environmental management program at the McArthur River Operation, as identified in their CNSC-approved management system program. CNSC staff reviewed and assessed the objectives, goals and targets through regular compliance verification activities. CNSC staff noted that Cameco had continued with routine inspections, internal audits, environmental training and periodic reviews of environmental monitoring data. These activities were conducted to ensure continual improvement and to confirm that the controls put in place to protect the environment are effective.

#### Effluent and emissions control

##### Treated effluent released to the environment

CNSC staff verified that treated effluent released to the environment was below regulatory requirements and has remained stable or has improved over the past five years. As discussed in section 2.4, constituents of potential concern (COPC) with potential to adversely affect the environment in treated effluent at multiple uranium mine and mill operations are molybdenum, selenium and uranium (figures 2.7 to 2.9). Of the three COPCs, molybdenum posed an elevated risk at the McArthur River Operation. In response, process changes such as adjusting pH and reagent rebalancing were implemented to reduce molybdenum concentrations in treated effluent. From 2014 to 2017 concentrations of molybdenum were relatively stable and well below the operational action level as displayed in figure 2.7. In 2018, concentrations of molybdenum were reduced by approximately 90 percent as a result of placing the facility into a state of care and maintenance.

In addition to the COPC with the potential to adversely impact the environment, Cameco analyzed treated effluent from the McArthur River Operation for concentrations of various other COPCs, such as radium-226, arsenic, copper, lead, nickel, zinc, total suspended solids (TSS) and pH. CNSC staff reviewed the effluent treatment concentrations and confirmed that the McArthur River Operation continued to meet the discharge limits set out in the Metal and Diamond Mining Effluent Regulations [5] (section 2.4).

On March 9, 2018, Cameco reported the exceedance of a radium action level when it determined that the averaged radium over 10 ponds exceeded 0.30 Bq/L. The licensee has resolved the issue, and there was no impact on the environment or the health and safety of persons as a result of this action level exceedance. Further information on this exceedance is included in appendix J.

The CNSC will continue to review effluent quality results to ensure that effluent treatment performance remains effective. Figure 4.3 shows a monitoring pond at the McArthur River Operation.

#### Air emissions released to the environment

The CNSC requires that Cameco maintain an air and terrestrial monitoring program at its McArthur River Operation. Air and terrestrial monitoring at the McArthur River facility includes ambient radon, total suspended particulate (TSP), soil sampling and lichen sampling to assess the impact of air emissions. An analysis of blueberry chemistry was also included to align with country food studies. Blueberry twigs are monitored to determine whether soil-borne contaminants (when present) are being absorbed through the roots into the growing plant parts. The monitoring of soil and blueberry stems/twigs was completed in the summer of 2018. The results are within the historical range for the stations sampled.

Radon in ambient air is monitored using passive track etch cups at 12 monitoring stations around the operation. Figure 4.4 shows that the average concentrations of radon in ambient air from 2014 to 2018 were similar to past performance, with radon concentrations typical of the northern Saskatchewan regional background of less than 7.4 Bq/m3 to 25 Bq/m3. The average radon concentrations are less than the reference level of 55 Bq/m3, which represents an incremental dose of 1 mSv/year above background.

Two high-volume air samplers were used to collect and measure TSP in air. Taking the average of the two stations, the TSP levels were lower than provincial standards (see table 4.2). The mean concentrations of metal and radionuclides adsorbed to TSP were low and below the reference annual air quality levels identified in table 4.2.

Table 4.2: McArthur River Operation concentrations of metal and radionuclides in air, 2014–18*
Parameter Reference annual air quality levels 2014 2015 2016 2017 2018
TSP (µg/m3) 60 (3) 8.94 6.31 2.24 3.24 1.69
As (µg/m3) 0.06 (1) 0.0001 0.0001 0.0001 0.0001 0.0006
Cu (µg/m3) 9.6 (1) 0.00835 0.00513 0.0065 0.0064 0.0072
Ni (µg/m3) 0.04 (1) 0.00085 0.00067 0.0007 0.0007 0.0006
Pb (µg/m3) 0.10 (1) 0.0012 0.00118 0.0011 0.0006 0.0008
Se (µg/m3) 1.9 (1) 0.0004 0.00004 0.00004 0.00004 0.00003
Zn (µg/m3) 23 (1) 0.01225 0.00980 0.0106 0.0084 0.0295
Pb-210 (Bq/m3) 0.021 (2) 0.00032 0.00032 0.0002 0.0004 0.0003
Po-210 (Bq/m3) 0.028 (2) 0.00009 0.00008 0.0001 0.0001 0.0001
Ra-226 (Bq/m3) 0.013 (2) 0.00002 0.00001 0.00004 0.00001 0.00001
Th-230 (Bq/m3) 0.0085 (2) 0.00001 0.00002 0.0001 0.0001 0.00001
U (µg/m3) 0.06 (1) 0.0005 0.0003 0.0004 0.0003 0.0001

1 Reference annual air quality levels are derived from Ontario’s 24-hour ambient air quality criteria (2012).

2 Reference level is derived from International Commission on Radiological Protection (ICRP) Publication 96, Protecting People Against Radiation Exposure in the Event of a Radiological Attack.

3 Saskatchewan Environmental Quality Guidelines, Table 20: Saskatchewan Ambient Air Quality Standards.
Values are calculated as geometric means.

* Reference levels based on Province of Ontario ambient air quality criteria and are shown for reference only.
No federal or Saskatchewan provincial limits were established at the time of this report.

Soil and terrestrial vegetation may be affected by the atmospheric deposition of particulate and adsorbed metals and radionuclides associated with onsite activities. A terrestrial monitoring program is in place and includes triennial measurements of metals and radionuclides in soil and blueberry samples.

Soil, blueberry twig and lichen samples were last collected in 2018 as required by the triennial sampling program. The results indicated that the parameters measured were within historical ranges.

CNSC staff concluded that the level of airborne particulate contaminants produced by the McArthur River Operation is acceptable and does not pose a risk to the environment.

#### Uncontrolled releases

In 2018, two events reported to the CNSC were classified as a release (spill) of a hazardous substance to the environment. These spills were of low safety significance and the reporting of this event met the requirements of REGDOC-3.2.1, Public Information and Disclosure [2]:

• On August 6, 2018, Cameco staff conducted a routine inspection of treated effluent monitoring ponds 3 and 4. This inspection revealed that the temporary repairs completed in May had failed. An estimated 8,000 m3 of treated water was released from these ponds through the liner into the ground.
• On August 25, 2018, a mechanic entering module 1 of the freeze plant determined that a small amount of ammonia had been released from a cracked vessel sight glass into the freeze plant. The exact amount of ammonia released is unknown, but none of the ammonia detectors in the plant displayed elevated concentrations of ammonia during this event.

There were no impacts to the environment as a result of the spills and CNSC staff were satisfied with the corrective actions taken. CNSC staff rated the spills as low significance. Appendix I contains a brief description of the spills and the corrective actions taken by the licensee. CNSC spill rating definitions can be found in appendix I, table I-2.

Figure 2.12 in section 2 shows the number of spills at the McArthur River Operation from 2014 to 2018.

#### Assessment and monitoring

CNSC staff confirmed that the licensee, in accordance with the McArthur River environmental protection program, successfully carried out the required environmental monitoring.

Through the compliance verification activities conducted and the review of annual reports and EPRs, CNSC staff concluded that the environmental monitoring conducted at the McArthur River Operation met regulatory requirements. Consequently, CNSC staff concludes that the environment remains protected.

#### Environmental risk assessment

In 2015, the McArthur River EPR and updated ERA for 2010 to 2014 were submitted to the CNSC and the Saskatchewan Ministry of Environment. CNSC staff reviewed the environmental monitoring results for air, soil, vegetation, water, groundwater and sediment, as well as the health indicators for fish and their prey inhabiting sediment and confirmed that the results were within those predicted in the ERA.

After reviewing the EPR and ERA, CNSC staff concluded that adequate measures have been taken at the McArthur River Operation to protect the environment.

#### Protection of the public

Cameco is required to demonstrate that the health and safety of the public are protected from exposures to hazardous substances released from the McArthur River Operation. The effluent and environmental monitoring programs currently conducted by the licensee are used to verify that releases of hazardous substances do not result in environmental concentrations that may affect public health.

The CNSC receives reports of discharges to the environment through the reporting requirements outlined in the licence and licence conditions handbook. The review of McArthur River Operation’s hazardous (non-radiological) discharges to the environment indicates that the public and the environment are protected. CNSC staff confirmed that environmental concentrations in the vicinity of the McArthur River Operation remained within those predicted in the 2015 ERA, and that human health remained protected.

Based on compliance verification activities that included inspections, reviews of licensees’ reports, work practices and monitoring results for 2018, CNSC staff concluded that the McArthur River Operation’s environmental protection program continued to be effective at protecting the public and the environment.

### 4.4 Conventional health and safety

CNSC staff rated the conventional health and safety SCA as satisfactory based on regulatory oversight activities conducted during 2018.

McArthur River Operation – conventional health and safety ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

#### Practices

To promote continued effective safety performance, the McArthur River Operation has implemented a health and safety management program to identify and mitigate risks at the facility. The program includes a safety permit system, continued training, planned internal inspections, occupational health committees and incident investigations. The incident reporting system includes investigating and reporting on near misses and reduces chances that future incidents that could cause injury. CNSC staff verified that Cameco’s conventional health and safety work practices and conditions at the McArthur River Operation met regulatory requirements in 2018.

#### Performance

As shown in table 4.3, no lost-time injuries (LTIs) were reported at the McArthur River Operation in 2018. The severity rating of 23.2 is related to ongoing time lost due to injuries that occurred in 2016 and 2017.

Included in this report is the total recordable incident rate (TRIR). The TRIR is the incident frequency rate that measures the number of fatalities, lost-time injuries and other injuries requiring medical treatment per 200,000 person-hours worked.

2014 2015 2016 2017 2018 1* 0 2** 1 0 14.6* 7.31* 0 12.11 23.2*** 0.11* 0 0.24** 0.15 0 --- --- 3.74 5.24 5.02 1 An injury that takes place at work and results in the worker being unable to return to work for a period of time. 2 A measure of the total number of days lost to injury for every 200,000 person-hours worked at the facility. Accident severity rate = [(# of days lost in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 3 A measure of the number of LTIs for every 200,000 person-hours worked at the facility. Accident frequency rate = [(# of injuries in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 4 A measure of the number of fatalities, lost-time injuries and other injuries requiring medical treatment for every 200,000 person-hours worked at the facility. Recordable incident rate = [(# of incidents in last 12 months) / # of hours worked in last 12 months)] x 200,000. * A lifting injury in 2014 eventually led to surgery in 2015, resulting in lost time. Consequently, the number of 2014 LTIs increased from 0 to 1, the severity rate went from 0 to 14.6 and the frequency rate rose from 0 to 0.11. The 2015 severity rate was also affected due to lost time in 2015. ** A hip injury in 2016 resulted in the worker being unable to return to work in 2017, resulting in lost time. Consequently, the number of 2016 LTIs increased from 1 to 2, and the frequency rate rose from 0.12 to 0.24. *** See explanation in preceding paragraph.

Compliance verification activities confirmed that the McArthur River Operation focuses on the prevention of accidents, reducing LTIs and the number of injuries requiring medical treatment.

#### Awareness

CNSC staff observed that the conventional health and safety programs at the McArthur River Operation continued to provide education, training, tools and support to workers. Managers, supervisors and workers share and promote the idea that safety is the responsibility of all individuals. The facility operations’ management stresses the importance of conventional health and safety through regular communication, management oversight and the continual improvement of safety systems.

CNSC staff verified that the health and safety program at the McArthur River Operation met regulatory requirements.

## 5. Rabbit Lake Operation

The Rabbit Lake Operation is located 750 kilometres north of Saskatoon, Saskatchewan. Owned and operated by Cameco Corporation, the facility stretches across approximately 20 kilometres (see figure 5.1). The Eagle Point underground mine is located at the northern margin of the property. Moving southward, three mined-out pits, two reclaimed, A-Zone and D-Zone, and one flooded, B-Zone pit all bordering Collins Bay of Wollaston Lake. The B-Zone pit remains isolated from Collins Bay by an intact dyke. In the central part of the property, the mined-out Rabbit Lake pit was converted to a tailings management facility (TMF). Adjacent to the in-pit TMF is the mill. South of the mill is the above ground TMF, which has not received tailings since 1985. At the southern margin, after passage through settling ponds, all treated effluent which must meet discharge limits is continuously discharged and eventually reaches Hidden Bay of Wollaston Lake.

In October 2013, the Commission issued a 10-year licence following a public hearing in
La Ronge, Saskatchewan. Cameco’s licence for the Rabbit Lake Operation expires on October 31, 2023.

Mining production data for the Rabbit Lake Operation are provided in table 5.1.

Table 5.1: Rabbit Lake Operation mining production data, 2014–18
Mining 2014 2015 2016 2017 2018
Ore tonnage (Mkg/year) 328.13 309.50 79.87 0 0
Average ore grade mined (%U) 0.48 0.54 0.59 0 0
Uranium mined (Mkg U/year) 1.57 1.66 0.47 0 0

On April 21, 2016, Cameco formally announced that, due to market conditions, production at the Rabbit Lake Operation was to be suspended and the facility was placed in a safe state of care and maintenance. This decision allows Cameco the flexibility to resume production when market conditions improve.

No uranium concentrate was produced nor was any ore production conducted at the Rabbit Lake Operation during the 2018 reporting period. Table 5.2 provides milling production data from 2014 to 2018.

Table 5.2: Rabbit Lake Operation milling production data, 2014–18
Milling 2014 2015 2016 2017 2018
Mill ore feed (Mkg/year) 386.97 313.71 61.67 0 0
Average annual mill feed grade (%U) 0.42 0.53 0.69 0 0
Percent uranium recovery (%) 97.3 97.1 97.0 0 0
Uranium concentrate produced (Mkg U/year) 1.60 1.62 0.43 0 0
Authorized annual production (Mkg U/year) 4.25 4.25 4.25 4.25 4.25

Cameco has implemented the safe transition of the operations to care and maintenance. The focus was on three key areas: the preservation of facilities and equipment to ensure future availability; the ongoing collection and treatment of contaminated water from various areas of the operation; and the maintenance of operational compliance with applicable regulations, approvals and licensed programs.

The transition to care and maintenance relates to the suspension of production and the safe shutdown of related infrastructure and systems. The main functional areas to be managed include mill operations, mine operations and tailings management. A submission updating the plan and process to be followed and the status of the facility was provided to the CNSC and the Saskatchewan Ministry of Environment in October 2016. The submission has been reviewed by both agencies and the measures and activities outlined have been accepted. The following summarizes the transition initiatives.

#### Mill operations

The mill’s transition to care and maintenance is similar to a routine maintenance shutdown event:

• Mill production circuits were emptied, flushed, cleaned and preserved.
• The mill ore pad was emptied of remaining ore inventory.
• The water treatment circuit was maintained and restored to normal operating status.
• Sulphuric acid inventories were maximized, and acid plant operations were suspended.
• Mill ventilation was safely optimized for energy and heating use to reflect the mill circuits’ status.
• Hazardous materials were transported to other Cameco facilities or returned to the supplier.
• Inactive areas were added to routine inspection schedules, with checks conducted and documented on a regular basis.
• The required fire protection systems will continue to be maintained throughout the main mill complex.

#### Mine operations

No exploration, development or production activities took place in 2018. During the care and maintenance period, activities at the Eagle Point mine were minimized and the focus was on the continued dewatering of the mine. Underground work consisted only of basic and required inspections and maintenance:

• All development and production work areas have been made safe, and ground conditions have been assessed for stability and verified by a qualified third-party evaluation.
• Inactive areas have been sealed with bulkheads, and mine service infrastructure has been removed from these areas.
• The mine water collection and dewatering system has been simplified and centralized.
• Ventilation systems have been safely optimized for heat and energy use.
• Mine mobile equipment has been stored in the mine.
• All explosives have been removed from underground, and the remaining inventory has been removed by the vendor.
• Non-essential surface facilities have been vacated and secured.

The licensee conducts and reports on routine inspections of the mine to ensure proper functioning of dewatering and ventilation systems and to monitor for unusual or changing conditions. Emergency response is maintained by the licensee in accordance with the requirements of the Saskatchewan Ministry of Labour Relations and Workplace Safety.

#### Tailings management

The Rabbit Lake in-pit TMF continued to operate during the care and maintenance period. The primary operating functions involved: storing solids produced by the mill water treatment system; providing ongoing dewatering of tailings solids and hydraulic containment of pore water, supernatant, surface runoff and groundwater from the existing catchment area; and providing short-term water storage capacity as part of the facility’s water management system. Figure 5.2 shows an inspector measuring the gamma dose rate in the B-Zone reclamation area.

#### Reclamation

No changes to the existing preliminary decommissioning plan and cost estimate have occurred due to the suspension of production. Progressive reclamation activities will continue throughout the care and maintenance period. Cameco must notify CNSC staff if the scope of activities or timeline for decommissioning changes relative to the current operating status.

CNSC staff have verified the care and maintenance status of the mine and mill and the continuation of reclamation activities through desktop reviews of applications, reports and onsite inspections. CNSC staff will continue to monitor and review the Rabbit Lake Operation’s water management practices and reclamation activities to ensure the environment is protected during this period of care and maintenance.

### 5.1 Performance

For 2018, CNSC staff rated all 14 safety and control areas (SCAs) as satisfactory based on regulatory oversight activities. Ratings at the Rabbit Lake Operation for these 14 SCAs during the five-year period from 2014 to 2018 are shown in appendix E. This report focuses on the three SCAs that cover many of the key performance indicators for these facilities: radiation protection, environmental protection and conventional health and safety.

In 2018, CNSC staff carried out compliance inspections covering the operating performance, emergency management and fire protection, fitness for service, conventional health and safety, radiation protection, management systems, environmental protection and safety analysis SCAs. Nine non-compliance were identified as a result of CNSC inspections at the Rabbit Lake Operation in the 2018 calendar year. These non-compliance were of low safety significance and related to the conventional health and safety, management system and radiation protection SCAs. Corrective actions implemented by the licensee have been reviewed and accepted by CNSC staff. All actions resulting from non-compliance have been closed. A list of inspections is provided in appendix B.

For 2018, CNSC staff continued to rate the radiation protection SCA at Rabbit Lake as satisfactory based on regulatory oversight activities.

Rabbit Lake Operation – radiation protection ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

The sources of radiological exposure at the Rabbit Lake Operation were from mining at the Eagle Point underground mine and from milling uranium ore into yellowcake at the Rabbit Lake mill. The effective dose contributors to nuclear energy workers (NEWs) at Rabbit Lake were radon progeny (75%), gamma radiation (17%), long-lived radioactive dust (LLRD) (6%) and radon gas (2%). Effective doses to NEWs from exposures to radon progeny, radon gas and LLRD are controlled through the effective use of source control, ventilation, contamination control and personal protective equipment (PPE). Gamma radiation exposure is controlled through practises related to the effective use of time, distance and shielding.

In 2018, CNSC staff were satisfied that the radiation protection program and practices at the Rabbit Lake Operation remained effective at controlling radiological exposure to workers. The doses to workers remained below regulatory limits and as low as reasonably achievable (ALARA). No exceedances of action levels were reported at the Rabbit Lake Operation in 2018.

#### Application of ALARA

In 2018, the collective dose to NEWs at the Rabbit Lake Operation was 76 person-millisieverts (p-mSv), an approximate 20 percent increase over the 2017 value of 61 p-mSv (see figure 5.3). The increase is a result of changes to staffing and maintenance activities and is of low regulatory significance.

In 2018, Rabbit Lake Operation identified two targets for the ALARA program. The first was to investigate, map, and develop an action plan to control radon progeny. The second was to reduce average and maximum effective doses to workers.

CNSC staff have verified through regulatory oversight activities that Cameco continued to keep worker exposures ALARA .

#### Worker dose control

During 2018, the average individual effective dose for NEWs was 0.46 mSv and the maximum individual effective dose was 1.70 mSv. This is consistent with the average effective dose of 0.40 mSv and the maximum individual dose of 1.56 mSv in 2017. As shown in section 2 and figures 2.5 and 2.6, all individual effective doses for NEWs were below the annual regulatory limit of 50 mSv and the five-year limit of 100 mSv.

Based on CNSC staff’s compliance verification activities, such as inspections, reviews of licensees’ reports and work practices, and monitoring of results and individual effective dose results for 2018, CNSC staff were satisfied that the Rabbit Lake Operation continued to be effective at controlling radiation doses to workers.

### 5.3 Environmental protection

For 2018, CNSC staff continued to rate the environmental protection SCA at Rabbit Lake as satisfactory based on regulatory oversight activities. CNSC staff concluded that the licensee’s environmental protection program was effectively implemented and met all regulatory requirements.

Rabbit Lake Operation – environmental protection ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

#### Environmental management system

The environmental management system at the Rabbit Lake Operation includes activities such as establishing annual environmental objectives, goals and targets. Cameco conducts internal audits of its environmental protection program at the Rabbit Lake Operation as identified in its CNSC-approved management system program. CNSC staff review and assess the objectives, goals and targets through regular compliance verification activities. CNSC staff noted that Cameco continued to conduct routine inspections, internal audits, environmental training and periodic reviews of environmental monitoring data. These activities were conducted to ensure continual improvement and to confirm that the controls put in place to protect the environment are effective.

#### Effluent and emissions control

##### Treated effluent released to the environment

For previously identified constituents of potential concern (COPC) with the potential to adversely affect the environment (i.e., uranium, molybdenum and selenium), the effluent treatment system at the Rabbit Lake Operation continued to meet performance expectations in terms of reducing the concentrations of these parameters (see figures 2.7 to 2.9 of section 2). CNSC staff verified that molybdenum concentrations decreased from 2012 levels, they were relatively consistent from 2014 to 2016, and they showed a further decline in 2017 and 2018.

In 2006, a review titled Uranium in Effluent Treatment Process identified a concentration of uranium in effluent of 0.1 mg/L as a potential treatment design objective that could be achieved and be protective of the environment. The 2007 treatment circuit modifications have also been successful in meeting the uranium target objective of 0.1 mg/L. CNSC staff also confirmed that selenium concentrations remained consistent with previous years’ figures (figure 2.8) and showed a decline in the past four years.

Cameco also analyzed treated effluent for concentrations of various other contaminants, such as radium-226, arsenic, copper, lead, nickel, zinc and total suspended solids (TSS), as well as pH levels. As shown in section 2.4, CNSC staff verified that the Rabbit Lake Operation continued to meet the discharge limits set out in the Metal Diamond Mining Effluent Regulations.

Cameco’s environmental management system and effluent monitoring programs at Rabbit Lake met regulatory requirements, and all treated effluent discharged to the environment complied with licence requirements. In 2018, the concentrations of regulated parameters in treated effluent released to the environment were well below the regulatory limits and there were no exceedances of environmental action levels at the Rabbit Lake Operation. Figure 5.4 shows the B-Zone settling pond at the Rabbit Lake Operation. CNSC staff will continue to review effluent quality results to ensure that effluent treatment performance remains effective.

##### Air emissions released to the environment

Cameco also maintains an air and terrestrial monitoring program at Rabbit Lake. Air and terrestrial monitoring at the Rabbit Lake facility includes ambient radon, total suspended particulate (TSP), sulphur dioxide, soil sampling and lichen sampling to assess the impact of air emissions.

Radon in ambient air around the Rabbit Lake Operation is monitored at 18 stations using passive track etch cups. Figure 5.5 shows that the average concentrations of radon in ambient air from 2014 to 2018 is similar to background concentrations for northern Saskatchewan’s regional baseline of less than 7.4 Bq/m3 to 25 Bq/m3. The average radon concentrations are less than the reference level of 55 Bq/m3, which represents an incremental dose of 1 mSv/year above background.

Three high-volume air samplers were used to collect and measure TSP in air. The TSP levels from the average of the three stations were lower than provincial standards (see table 5.3). TSP samples were also analyzed for concentrations of metals and radionuclides. The mean concentrations of metals and radionuclides adsorbed to TSP are low and remained below the reference annual air quality levels identified in table 5.3.

Table 5.3: Rabbit Lake Operation concentrations of metal and radionuclides in air, 2014–18
Parameter Reference annual air quality levels* 2014 2015 2016 2017 2018
TSP (µg/m3) 60 (3) 6.21 6.87 4.97 4.79 3.91
As (µg/m3) 0.06 (1) 0.000337 0.000207 0.000290 0.000285 0.000365
Ni (µg/m3) 0.04 (1) 0.000138 0.000192 0.000540 0.000404 0.000183
Pb-210 (Bq/m3) 0.021 (2) 0.000013 0.000015 0.000011 0.000013 0.000015
Ra-226 (Bq/m3) 0.013 (2) 0.000002 0.000001 0.000002 0.000004 0.0000002
Th-230 (Bq/m3) 0.0085 (2) 0.000003 0.000001 0.000002 0.000004 0.0000003
U (µg/m3) 0.06 (1) 0.001960 0.002341 0.000899 0.000190 0.000277

1 Reference annual air quality levels are derived from Ontario’s 24-hour ambient air quality criteria (2012).

2 Reference level is derived from International Commission on Radiological Protection (ICRP) Publication 96,
Protecting People Against Radiation Exposure in the Event of a Radiological Attack.

3 Saskatchewan Environmental Quality Guidelines, Table 20: Saskatchewan Ambient Air Quality Standards.
Values are calculated as geometric means.

* Reference levels based on Province of Ontario ambient air quality criteria and are shown for reference only.
No federal or Saskatchewan provincial limits were established at the time of this report.

Daily in-stack monitoring of sulphur dioxide emissions from the mill acid plant was discontinued in 2017 for the duration of the care and maintenance period, as the acid plant and mill processing circuits were not operating.

Soil and terrestrial vegetation may be affected by the atmospheric deposition of particulate and adsorbed metals and radionuclides associated with onsite activities. A terrestrial monitoring program is in place and includes measurements of metals and radionuclides in lichen.

Lichen sampling has been conducted for three decades at the Rabbit Lake Operation, most recently in 2013. The next sampling is scheduled for 2019. CNSC staff concluded that the level of airborne particulate contaminants produced by the Rabbit Lake Operation does not pose a risk to lichen consumers, such as caribou.

#### Uncontrolled releases

In 2018, two events were reported to CNSC staff as a release (spill) of hazardous substances to the environment. The spill was minor and there were no residual impacts on the environment. The licensee’s report of this event met the requirements of REGDOC‑3.2.1, Public Information and Disclosure [2]:

• July 22, 2018 a discharge of liquid propane from the 68,100 litre shotcrete plant storage tank was identified during an inspection. The employees noticed frost buildup on a valve on the liquid side of the line feeding the tank for the offload point. The employees assessed the situation and approached the valve from a safe direction. Upon reaching the valve, the employees noted an audible hiss and a small amount of liquid propane visibly leaking from the tank.
• November 18, 2018 an odour of propane was identified near the Environment and Health Laboratory building, near the main camp. It was determined that a valve stem on the liquid offloading line at the main camp propane farm had a small leak. As a result, the Environment and Health Laboratory building was evacuated until the leak was repaired.

Appendix H provides a brief description of the spills and actions taken by the licensee. CNSC staff reviewed the corrective actions taken by the licensee and found them to be acceptable. CNSC staff rated the 2018 spills as being of low significance in accordance with the definitions provided in appendix H, table I-2 of this report. Figure 2.12 in section 2 identifies the number of reportable environmental spills from 2014 to 2018 at the Rabbit Lake Operation.

#### Assessment and monitoring

CNSC staff confirmed that the licensee successfully carried out required environmental monitoring, in accordance with the Rabbit Lake environmental protection program.

Through the compliance activities conducted and the review of annual reports and EPRs, CNSC staff concluded that the environmental monitoring conducted at the Rabbit Lake Operation met regulatory requirements. Consequently, CNSC staff concluded that the environment remains protected.

#### Environmental risk assessment

The Rabbit Lake Operation EPR and updated ERA for 2010 to 2014 were submitted to the CNSC and the Saskatchewan Ministry of Environment in 2015. CNSC staff reviewed the environmental monitoring results for air, soil, vegetation, water, groundwater and sediment, as well as health indicators for fish and their prey inhabiting sediment, and they confirmed that the results were within those predicted in the ERA.

After reviewing the EPR and ERA, CNSC staff concluded that adequate measures have been taken at the Rabbit Lake Operation to protect the environment.

#### Protection of the public

Cameco is required to demonstrate that the health and safety of the public are protected from exposures to hazardous substances released from the Rabbit Lake Operation. The effluent and environmental monitoring programs currently conducted by the licensee are used to verify that releases of hazardous substances do not result in environmental concentrations that may affect public health.

The CNSC receives reports of discharges to the environment through the reporting requirements outlined in the licence and the licence conditions handbook. The review of Rabbit Lake Operation’s hazardous (non-radiological) discharges to the environment indicates that the public and environment are protected. CNSC staff confirmed that environmental concentrations in the vicinity of the Rabbit Lake Operation remained within those predicted in the 2015 ERA and that human health remained protected
in 2018.

Based on compliance verification activities that included inspections, reviews of licensees’ reports and work practices and monitoring results for 2018, CNSC staff concluded that the Rabbit Lake Operation’s environmental protection program continued to be effective at protecting the public and the environment.

### 5.4 Conventional health and safety

For 2018, CNSC staff continued to rate the conventional health and safety SCA as satisfactory based on regulatory oversight activities.

Rabbit Lake Operation - conventional health and safety ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

#### Practices

Cameco’s Rabbit Lake Operation has implemented a safety and health management program to identify and mitigate risks. The program includes internal inspections, a safety permit system, occupational health committees, training and incident investigations. CNSC staff monitor this program through compliance activities to ensure the protection of workers.

The incident reporting system at the Rabbit Lake Operation includes reporting on and investigating near misses with the aim of reducing future incidents that could cause injury. CNSC compliance verification activities confirmed that the Rabbit Lake Operation continued to focus on preventing accidents and injuries through the implementation of its health and safety management program.

#### Performance

No lost-time injuries were reported for the Rabbit Lake Operation in 2018. The lost-time injury (LTI) performance at the Rabbit Lake Operation from 2014 to 2018 is shown in table 5.4.

In this report, the total recordable incident rate (TRIR) is included for the last three years. The TRIR is the incident frequency rate that measures the number of fatalities, lost‑time injuries and other injuries requiring medical treatment, per 200,000 person-hours worked.

2014 2015 2016 2017 2018 1 2 1 0 0 11.4 55.3 2.65 0 0 0.15 0.33 0.27 0 0 --- --- 1.89 1.03 5.03 1 An injury that takes place at work and results in the worker being unable to return to work for a period of time. 2 A measure of the total number of days lost to injury for every 200,000 person-hours worked at the facility. Accident severity rate = [(# of days lost in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 3 A measure of the number of LTIs for every 200,000 person-hours worked at the facility. Accident frequency rate = [(# of injuries in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 4 A measure of the number of fatalities, lost‑time injuries and other injuries requiring medical treatment for every 200,000 person-hours worked at the facility. Recordable incident rate = [(# of incidents in last 12 months) / # of hours worked in last 12 months)] x 200,000.

#### Awareness

CNSC staff observed that Cameco’s conventional health and safety program at the Rabbit Lake Operation continued to provide education, training, tools and support to workers. Managers, supervisors and workers share and promote the idea that safety is the responsibility of all individuals. Facility management emphasizes the importance of conventional health and safety through regular communication, management oversight and the continual improvement of safety systems.

CNSC staff verified that the conventional health and safety program at the Rabbit Lake Operation remained effective at managing health and safety risks.

## 6. Key Lake Operation

Located approximately 570 kilometres north of Saskatoon, Saskatchewan, the Key Lake Operation, shown in figure 6.1, is owned and operated by Cameco Corporation. The operation began with two open-pit mines and a mill complex. The Gaertner open pit was mined from 1983 to 1987, followed by the Deilmann open pit until 1997.

Milling of the stockpiled Deilmann ore continued until 1999, when the McArthur River Operation began supplying ore slurry to the Key Lake mill. The Key Lake Operation continues today as a mill operation that processes McArthur River ore slurry and residual special waste from previous mining at Key Lake.

After open pit mining in the eastern pit of the Deilmann ore body was completed in 1995, the pit was converted to the engineered Deilmann tailings management facility (TMF), while mining continued in other parts of the pit area (see figure 6.2). Mill tailings continue to be deposited in this facility today.

In October 2013, the Commission issued a 10-year licence following a public hearing in
La Ronge, Saskatchewan. The Key Lake Operation licence expires on October 31, 2023.

On November 8, 2017, Cameco notified the CNSC that effective January 2018, they would be temporarily suspending production at the Key Lake Operation. This included all activities directly related to the processing of uranium ore. On July 25, 2018, Cameco notified the CNSC of its decision to suspend production at the Key Lake Operation for an indefinite period, until economic conditions improve.

Milling data for the Key Lake Operation during the five-year reporting period are presented in table 6.1. The Key Lake Operation operated in a state of care and maintenance for 2018.

Table 6.1: Key Lake Operation milling production data, 2014–18
Milling 2014 2015 2016 2017 2018
Mill ore feed (Mkg/year) 173.01 165.56 155.30 143.26 0
Average annual mill feed grade (% U) 4.29 4.47 4.51 4.37 N/A
Percentage of uranium recovery (%) 99.4 99.35 99.04 99.05 N/A
Uranium concentrate produced (Mkg U/year) 7.37 7.35 6.95 6.20 0.06*
Authorized annual production (Mkg U/year) 9.60 9.60 9.60 9.60 9.60
* Processing of remaining ore slurry from 2017.

### 6.1 Performance

The Key Lake Operation’s safety and control area (SCA) ratings for the five-year period from 2014 to 2018 are shown in appendix E. CNSC staff continued to rate all SCAs for 2018 as satisfactory based on regulatory oversight activities. This report focuses on the three SCAs that cover many of the key performance indicators for these uranium mine and mill operations: radiation protection, environmental protection, and conventional health and safety.

In 2018, CNSC staff carried out compliance inspections that covered multiple SCAs, as detailed in appendix B. Five instances of non-compliance were noted as a result of CNSC inspections at the Key Lake Operation for the 2018 calendar year. These instances of non-compliance were of low risk and related to the physical design, conventional health and safety, and emergency management and fire protection SCAs. The licensee has implemented corrective actions which have been reviewed and accepted by CNSC staff. A list of inspections can be found in appendix B of this report.

Based on regulatory oversight activities during the reporting period, CNSC staff rated the radiation protection SCA at Key Lake as satisfactory.

Key Lake Operation – radiation protection ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

The effective dose contributors to nuclear energy workers (NEWs) at the Key Lake mill were gamma radiation (38%), radon progeny (40%) and long‑lived radioactive dust (LLRD) (22%). Gamma radiation hazards are controlled through practices related to the effective use of time, distance and shielding. Radon progeny and LLRD are controlled through source control, ventilation contamination control and personal protective equipment (PPE).

In 2018, CNSC staff were satisfied that the radiation protection program and practices at the Key Lake Operation remained effective at controlling radiological exposure to workers. The doses to workers remained below regulatory limits and as low as reasonably achievable (ALARA). No exceedances of action levels were reported at the Key Lake Operation in 2018.

#### Application of ALARA

In 2018, the collective dose to NEWs at the Key Lake Operation was 88 person-millisieverts (p‑mSv), an 80-percent reduction from the 2017 value of 451 p-mSv (see figure 6.3), due to the transition to care and maintenance.

Cameco continued to meet its objectives in 2018 for keeping doses ALARA at Key Lake. To support this objective, the radiation area monitoring program was revised for the transition to care and maintenance. Weekly audits were also completed to ensure workers were wearing radiation monitoring devices such as gamma dosimeters and dust pumps.

#### Worker dose control

In 2018, the average individual effective dose to NEWs was 0.19 mSv, while the maximum individual effective dose received was 2.02 mSv. This compares to an average effective dose of 0.66 mSv and a maximum individual dose of 5.39 mSv in 2017. The effective doses received by workers in 2018 were lower than historic values because the facility is in a state of care and maintenance.

The maximum individual effective dose at the Key Lake Operation was identified in a mill operations worker who worked in the leaching and solvent extraction circuits during the first quarter of 2018 and multiple areas for the remainder of 2018. No worker exceeded the regulatory individual effective dose limit of 50 mSv in one year and 100 mSv in a five-year dosimetry period.

Based on their compliance verification activities, such as onsite inspections, reviews of licensee reports and work practices, monitoring of results and individual effective dose results, CNSC staff were satisfied that the Key Lake Operation continued to be effective at controlling radiation doses to workers in 2018.

### 6.3 Environmental protection

For 2018, CNSC staff continued to rate the environmental protection SCA as satisfactory based on regulatory oversight activities. CNSC staff concluded that the licensees’ environmental protection program was effectively implemented and met all regulatory requirements.

Key Lake Operation – environmental protection ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

#### Environmental management system

The environmental management system at the Key Lake Operation includes activities such as establishing annual environmental objectives, goals and targets. Cameco conducts internal audits of its environmental protection program at the Key Lake Operation, as identified in its CNSC-approved management system program. CNSC staff review and assess the objectives, goals and targets through regular compliance verification activities. CNSC staff noted that Cameco had continued to conduct routine inspections, internal audits, environmental training and periodic reviews of environmental monitoring data. These activities were conducted to ensure continual improvement and to confirm that the controls put in place to protect the environment are effective.

#### Effluent and emissions control

##### Treated effluent released to the environment

At the Key Lake Operation, two effluent streams are processed in separate treatment facilities before being released to the environment:

• The mill effluent is processed with a treatment system of chemical precipitation and liquid/solid separation, then released to Wolf Lake in the David Creek system.
• Effluent from dewatering wells of the Gaertner pit and Deilmann pit hydraulic containment systems is treated with a reverse osmosis system before being released to Horsefly Lake in the McDonald Lake system.

Monitoring confirmed that this effluent is within design specifications and the predictions outlined in the ERA. There were no exceedances of environmental action levels during the 2018 review period; however, in one event on October 12, 2018, approximately 10 m3 of high pH (10.16) effluent was released from the reverse osmosis treatment plant to Horsefly Lake. Although only a small volume of discharge was released, the pH was above the upper pH limit specified in the Metal and Diamond Mining Effluent Regulations (9.5) [5] and was also above the maximum grab sample limit within the provincial operating approval (9.5). As a comparison to the volume of elevated pH discharged during the event, the average daily discharge of treated effluent to the environment in the month of October 2018 was approximately 14,860 m3. An investigation was completed by Cameco and corrective actions were developed to improve pH control. CNSC staff reviewed the status of Cameco’s proposed follow-up actions during an inspection, and it was found to be acceptable.

The treated effluent quality presented in table 6.2 refers only to the mill effluent as released to the David Creek system. CNSC staff verified the concentration of all regulated contaminants in the treated mill effluent released in 2018 met licence limits. There were no exceedances of environmental action levels at the Key Lake Operation.

As discussed in section 2.4, constituents of potential concern (COPC) with potential to adversely affect the environment in treated effluent at uranium mine and mill operations are molybdenum, selenium and uranium (see figures 2.7 to 2.9). Of these, molybdenum and selenium concentrations were the primary concerns at the Key Lake Operation. The licensee completed process changes to reduce concentrations in treated effluent.

Reductions of molybdenum and selenium occurred from 2007 to 2009 when additional treatment components were installed and optimized. Figures 2.7 and 2.8 displays stable or declining concentrations of molybdenum and selenium in treated effluent from 2014 to 2018, indicating these parameters are being effectively controlled. Cameco Corporation submitted a molybdenum and selenium follow-up program closure report in 2018. Based on the results of the follow-up program, Cameco proposed that current regulatory monitoring requirements were sufficient to monitor future changes in sediment and other environmental receptors, and it proposed that the formal follow-up program cease. CNSC staff confirmed in March 2019 that the follow-up program can conclude, and monitoring requirements could be added to the environmental monitoring program for the facility.

Figure 2.9 indicates that uranium concentrations in treated effluent released from the Key Lake mill remain low and are again effectively controlled. In addition to analyzing treated effluent for uranium, molybdenum and selenium, Cameco analyzed it for concentrations of other COPCs, such as radium-226, arsenic, copper, lead, nickel, zinc and total suspended solids (TSS), as well as pH levels at Key Lake. As discussed in section 2.4, the Key Lake Operation continued to meet Metal and Diamond Mining Effluent Regulations [5] discharge limits.

CNSC staff will continue to review effluent quality results to ensure that the treatment of effluent remains effective.

##### Air emissions released to the environment

The air and terrestrial monitoring program at the Key Lake Operation includes ambient monitoring for sulphur dioxide, radon and total suspended particulate (TSP), as well as soil and lichen sampling to assess air quality. Air emissions monitoring from the mill stacks is also included in the air-quality monitoring program.

The Key Lake calciner stack was not sampled in 2018 due to the shutdown of this area at that time; the most recent stack test was completed in June 2017. Sulphur dioxide concentrations from the acid plant stack are monitored daily when in operation. In the beginning of 2018, concentrations were consistent with those reported since the commissioning of the new acid plant in 2012; however, the plant operated for only eight days in January 2018 and remained shut down for the rest of the

Radon in air around the Key Lake Operation is monitored at five stations using passive track etch cups. Figure 6.4 shows the average concentrations of radon in ambient air from 2014 to 2018. Ambient radon concentrations were typical of the northern Saskatchewan regional background of less than 7.4 Bq/m3 to 25 Bq/m3. The measured radon concentrations are also below a reference radon concentration of 55 Bq/m3, which is equal to an incremental dose of 1 mSv per year above background.

Five high-volume air samplers were used to collect and measure total suspended particulate (TSP). The TSP levels are below the province of Saskatchewan’s authorized concentration of contaminants monitored for ambient air quality, as listed in the facility’s approval to operate pollutant control facilities. TSP samples are also analyzed for concentrations of metals and radionuclides. The mean concentrations of metal and radionuclides adsorbed to TSP are low and below the reference annual air quality levels, as identified in table 6.2.

Table 6.2: Key Lake Operation concentrations of metal and radionuclides in air, 2014–18
Parameter Reference annual air quality levels* 2014 2015 2016 2017 2018
TSP (µg/m3) 60 (3) 15.10 13.77 10.77 11.90 8.80
As (µg/m3) 0.06 (1) 0.00444 0.0016 0.0010 0.0045 0.0021
Ni (µg/m3) 0.04 (1) 0.00340 0.0013 0.0007 0.0029 0.0011
Pb-210 (Bq/m3) 0.021 (2) 0.00044 0.0003 0.0003 0.0004 0.0002
Ra-226 (Bq/m3) 0.013 (2) 0.00022 0.0001 0.0001 0.0003 0.0001
Th-230 (Bq/m3) 0.0085 (2) 0.00022 0.0001 0.0001 0.0002 0.0001
U (µg/m3) 0.06 (1) 0.00794 0.0080 0.0076 0.0091 0.0012

1 Reference annual air quality levels derived from Ontario’s 24-hour ambient air quality criteria (2012).

2 Reference level from International Commission on Radiological Protection (ICRP) Publication 96,
Protecting People Against Radiation Exposure in the Event of a Radiological Attack.

3 Saskatchewan Environmental Quality Guidelines, Table 20: Saskatchewan Ambient Air Quality Standards.
Values are calculated as geometric means. Current air quality standard for Key Lake Operation is 70 µg/m3. The new Province of Saskatchwan standard will apply to the Key Lake Operation once the existing provincial approval is renewed or revised.

* Reference levels based on Province of Ontario ambient air quality criteria and are shown for reference only.
No federal or Saskatchewan provincial limits were established at the time of this report.

A sulphur dioxide monitor is located approximately 300 metres downwind of the mill facility and is used to continuously measure the ambient sulphur dioxide associated with mill emissions. The measured sulphur dioxide monitoring data (see figure 6.5) show no exceedances of the annual standard of 20 µg/m3 in 2018. The current air quality standard for Key Lake is 30 µg/m3, but the new standard of 20 µg/m3 will apply when the operation’s existing provincial permit is renewed or revised.

There was a substantial decline in sulphur dioxide emissions following the construction of a new acid plant in 2012. In 2016, acid production declined compared to past years. The concentrations recorded at the ambient monitoring station, which are directly impacted by weather conditions, showed a notable decline, and these lower concentrations were observed again in 2017 and 2018 as acid production levels remained low.

In addition to ambient air monitoring for sulphur dioxide, sulphate levels have been monitored in four lakes to measure the effects of sulphur dioxide emissions from the operation. The results of the 2018 lake sampling program continued to show that sulphate concentrations remain relatively unchanged from historical concentrations. CNSC staff concluded that the operations at Key Lake and the resulting sulphur dioxide emissions do not have an adverse effect on the sulphate levels in nearby lakes.

Soil and terrestrial vegetation may be affected by atmospheric deposition of particulate, adsorbed metals and radionuclides associated with onsite activities. The terrestrial monitoring program in place includes measurements of metals and radionuclides in soil and in lichen. Lichen and soil samples were collected in 2016 and will be collected again in 2021.

Based on the 2016 soil and lichen sampling results, CNSC staff concluded that the level of airborne particulate contaminants produced by the Key Lake Operation is acceptable and does not pose a risk to the environment.

#### Uncontrolled releases

In 2018, five events reported to CNSC staff were considered to be releases of hazardous substances to the environment:

• On May 2, 2018, anhydrous ammonia was released to the atmosphere from an intermittent leak from two valves on ammonia storage tank No.2. The volume released could not be estimated due to the intermittent nature of the leaks; however, there was no measurable change in the tank level as a result of the leaks.
• On June 29, 2018, anhydrous ammonia was released to the atmosphere from a valve on ammonia storage tank No. 1. No release volume could be estimated; however, there was no measurable change in the tank level as a result of the leak.
• On July 24, 2018, during an inspection of the fire suppression system valves, it was discovered that the low pressure carbon dioxide system level had dropped significantly in the storage tank. Approximately 170 kilograms of carbon dioxide were released to the atmosphere.
• On November 22, 2018, a propane leak to the atmosphere was detected from a two-inch plug near a propane tank valve at the reverse osmosis water treatment plant. The release volume was very small and could not be estimated.
• In December 2018, after a review of groundwater monitoring data, Cameco reported that an onsite monitoring well showed an increase in uranium concentrations. Follow-up samples were collected from this well and others in the area. The samples confirmed the rising uranium concentration. The investigation indicated that the likely source was sump No.2 in the molybdenum extraction building. An initial event report (IER) was discussed at a Commission meeting on May 15, 2019.

These spills were minor and reporting met the requirements of REGDOC-3.2.1, Public Information and Disclosure [2].

Appendix I provides a brief description of each spill and the actions taken by the licensee. With the exception of the elevated uranium observed in an onsite monitoring well, all corrective actions related to these spills have been completed. The investigation into the elevated uranium in a monitoring well is being undertaken. Cameco has been providing updates on the status of the investigation to CNSC staff, the province of Saskatchewan and local stakeholders and Indigenous groups. In addition, a complete facility assessment report will be prepared and submitted in early 2020. The assessment is being completed in accordance with both federal and provincial requirements. The installation of monitoring wells and soil sampling was completed in the summer of 2019, and water quality and soil samples are being analyzed. Although the investigation is not complete, the results to date continue to indicate that the elevated uranium is limited to the immediate area and there remains no risk to the surrounding environment. Once the assessment report is complete, it will be used to develop a corrective action plan. CNSC staff reviewed the corrective actions and found them to be acceptable. CNSC staff rated the 2018 spills at the Key Lake Operation as low significance as defined in table I-2, appendix I.

In response to ammonia releases in 2017, Cameco initiated a three-year staged project to refurbish the existing tanks and associated infrastructure at Key Lake. The project is intended to bring the ammonia tank system up to current standards, and address any tank corrosion and valving/piping concerns. The original proposal in 2018 was to work on ammonia tank No.1 with internal and external tank inspections, and replace the insulation and cladding, electrical and instrumentation components, and the existing tank valves. Additional isolation valves were also to be added to the vaporizers. This work was completed as planned in 2018; however, in response to ammonia leaks in May 2018, Cameco expedited the three-year program and the remainder of the work is expected to be completed in 2019. In addition to upgrading ammonia tank No.1 with its associated valves and piping, the valves and piping on tank No.2 were also upgraded in 2018.

Figure 2.12 in section 2 displays the number of environmental reportable spills, as well as the number of releases of hazardous material to the environment from the licensed activities at the Key Lake Operation from 2014 to 2018.

#### Assessment and monitoring

CNSC staff confirmed that the licensee, in accordance with the Key Lake environmental protection program, successfully carried out the required environmental monitoring.

Through the compliance activities carried out and the review of annual reports and EPRs, CNSC staff concluded that the environmental monitoring conducted at the Key Lake Operation met regulatory requirements. Consequently, CNSC staff concludes that the environment remains protected.

#### Environmental risk assessment

The Key Lake Operation EPR and updated ERA for 2010 to 2014 were submitted to the CNSC and the Saskatchewan Ministry of Environment in 2015. CNSC staff reviewed the environmental monitoring results for air, soil, vegetation, water, groundwater and sediment, as well as health indicators for fish and their prey inhabiting sediment, and confirmed that the results were within those predicted in the ERA.

After reviewing the EPR and ERA, CNSC staff concluded that adequate measures have been taken at the Key Lake Operation to protect the environment.

#### Protection of the public

Cameco is required to demonstrate that the health and safety of the public are protected from exposures to hazardous substances released from the Key Lake Operation. The effluent and environmental monitoring programs currently conducted by the licensee verify that releases of hazardous substances do not result in environmental concentrations that may affect public health.

The CNSC receives reports of discharges to the environment through the reporting requirements outlined in the Key Lake licence and licence conditions handbook. A review of the hazardous (non-radiological) discharges to the environment indicates that the public and the environment are protected. CNSC staff confirmed that environmental concentrations in the vicinity of the Key Lake Operation remained within those predicted in the 2013 ERA and that human health remained protected in 2018.

Based on compliance verification activities that included inspections, reviews of licensees’ reports and work practices, and monitoring results for 2018, CNSC staff concluded that the Key Lake Operation’s environmental protection program continued to be effective at protecting the public and the environment.

### 6.4 Conventional health and safety

For 2018, CNSC staff continued to rate the conventional health and safety SCA as satisfactory, based on regulatory oversight activities.

Key Lake Operation – conventional health and safety ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

#### Practices

The Key Lake Operation’s incident reporting system records health- and safety‑related events and uses several layers of review in investigations. Corrective measures are tracked and assessed for effectiveness before the incident record is closed. The Key Lake Operation continued its planned health and safety inspection program in 2018. Any items of concern found during these inspections are included in the licensee’s incident reporting system.

#### Performance

There were two lost-time injuries (LTIs) at the Key Lake Operation between 2014 and 2018 (see table 6.3). There were no LTIs in 2018.

Included in this report is the total recordable incident rate (TRIR) for the last three years. The TRIR is the incident frequency rate that measures the number of fatalities, lost‑time injuries and other injuries requiring medical treatment.

2014 2015 2016 2017 2018 0 0 2 0 0 0 0 71.0 0 0 0 0 0.41 0 0 --- --- 6.17 3.48 2.59 1 An injury that takes place at work and results in the worker being unable to return to work for a period of time. 2 A measure of the total number of days lost to injury for every 200,000 person-hours worked at the facility. Accident severity rate = [(# of days lost in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 3 A measure of the number of LTIs for every 200,000 person-hours worked at the facility. Accident frequency rate = [(# of injuries in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 4 A measure of the number of fatalities, lost‑time injuries and other injuries requiring medical treatment for every 200,000 person-hours worked at the facility. Recordable incident rate = [(# of incidents in last 12 months) /(# of hours worked in last 12 months)] x 200,000.

#### Awareness

CNSC staff evaluated Cameco’s conventional health and safety programs at Key Lake and determined that it continued to provide education, training, tools and support to workers. The idea that safety is the responsibility of all individuals is promoted by the licensee’s managers, supervisors and workers. The licensee’s management stresses the importance of conventional health and safety through regular communication, management oversight and continual improvement of safety systems.

CNSC staff’s compliance verification activities concluded that Cameco’s health and safety program at the Key Lake Operation met regulatory requirements in 2018.

## 7. McClean Lake Operation

Orano Canada Inc. (Orano) is the operator of the McClean Lake Operation. In July 2018 a Commission panel approved the change of the licensee’s name from AREVA Resources Canada Inc. (AREVA) to Orano Canada Inc. and issued amended licence UMOL-MINEMILL-McCLEAN.01/2027.

The McClean Lake Operation is a uranium mine and mill facility located approximately 750 kilometres north of Saskatoon in the Athabasca Basin of northern Saskatchewan. Ownership of the McClean Lake Operation is held by Orano (70%), Denison Mines Inc. (22.5%) and Overseas Uranium Resources Development Canada Co. Ltd. (7.5%). The McClean Lake Operation includes the John Everett Bates (JEB) milling area, Sue mining area, JEB tailings management facility (TMF) and the undeveloped McClean, Midwest and Caribou ore deposits.

An aerial view of the facility is presented in figure 7.1. Figure 7.2 shows CNSC staff making observations at the McClean Lake Sue pit during an inspection.

Following a public hearing held on June 7 and 8, 2017, in La Ronge, Saskatchewan, the current operating licence was renewed on July 1, 2017, and expires on June 30, 2027. This licence authorizes the operation of a nuclear facility for mining uranium ore, processing high-grade ore slurry from Cameco Corporation’s Cigar Lake Operation, producing uranium concentrate and disposing of tailings at the JEB TMF. The Commission amended the McClean Lake operating licence on July 1, 2018, to reflect the licensee’s corporate name change from AREVA Resources Canada Inc. to Orano Canada Inc.

Construction of the McClean Lake Operation began in 1994. The milling of ore and processing of yellowcake product began in 1999. The McClean Lake Operation was designed and constructed with radiation protection features (e.g., lead shielding, concrete enclosures for storage and leach tanks) for processing undiluted high-grade ore averaging from 20 percent uranium to as high as 30 percent uranium. The mining and milling of uranium ore from five open-pit mines has been completed and conventional mining has not been carried out at the McClean Lake Operation since 2008. Mill tailings have been deposited in the JEB TMF which was engineered from the mined-out JEB open pit.

In July 2010, ore processing at the McClean Lake Operation was suspended, and the mill was temporarily shut down due to a shortage of ore. Shipments of high-grade ore slurry from Cameco’s Cigar Lake mine began in March 2014, and the McClean Lake Operation restarted in September 2014.

CNSC staff confirmed that the McClean Lake Operation’s production did not exceed the authorized annual production limit. Table 7.1 presents milling production data for the McClean Lake Operation for the five-year reporting period.

Table 7.1: McClean Lake Operation milling production data, 2014–18
Milling 2014 2015 2016 2017 2018
Mill ore feed (Mkg/year) 7.83 25.52 37.20 36.35 42.9
Average annual mill feed grade (% U) 3.00 17.56 18.08 19.30 16.26
Percentage of uranium recovery (%) 97.54 98.99 99.10 99.03 98.94
Uranium concentrate produced (Mkg U) 0.200 4.30 6.67 6.93 6.94
Authorized annual production (Mkg U/year) 5.00 5.00 9.23 9.23 9.23

In April 2010, Orano submitted an application to the CNSC requesting approval for its JEB TMF Optimization Project. CNSC staff reviewed the application and approved the project in September 2010. A two-phase plan was proposed and stage 1 of the project was completed in 2012–13 (re-sloping of TMF 1V:1.5H slope, placement of manufactured soil bentonite liner and placement of rip-rap protection). In 2017, Orano continued working on the removal of infrastructure impacting stage 2 re-sloping work and completed the following projects:

• contaminated landfill relocation
• tailings pipe bench relocation
• JEB TMF infrastructure decommissioning

Orano completed optimization stage 2 in the summer of 2018. This involved re‑sloping the current TMF slope to a 1V:3H slope, placing the liner at the final elevation of 443 metres above sea level (mASL) and putting in place rip-rap protection.

In June 2016, Orano submitted an application to expand the JEB TMF. Orano expects to generate approximately 2.4 million cubic metres of tailings over the next 18 years of operation. The TMF expansion would provide the additional required tailings storage capacity during the continued operation of the McClean Lake mill. CNSC staff accepted the JEB TMF expansion application, and it was presented to the Commission as part of the 2017 licence renewal. Orano indicated that construction activities for the JEB TMF expansion would begin in either 2019 or 2020. CNSC staff will continue to monitor progress through ongoing compliance activities.

### 7.1 Performance

Ratings for all 14 safety and control areas (SCAs) for the five-year period from 2014 to 2018 are shown in appendix E. For 2018, CNSC staff continued to rate all SCAs as satisfactory based on regulatory oversight activities, with the exception of radiation protection, which continued to be rated fully satisfactory, as described in section 7.2. This report focuses on the three SCAs that cover many of the key performance indicators for the uranium mines and mills: radiation protection, environmental protection, and conventional health and safety.

In 2018, CNSC staff carried out focused compliance inspections that covered the operating performance, conventional health and safety, and waste management SCAs, in addition to conducting general inspections that included multiple SCAs. Three instances of non-compliance were noted during CNSC inspections at the McClean Lake Operation for the 2018 calendar year. These instances of non-compliance were of low risk and related to the conventional health and safety and the fire protection and emergency management SCAs. The licensee implemented corrective actions which were reviewed and accepted by CNSC staff. A list of inspections can be found in appendix B.

From 2014 to 2016, CNSC staff continued to rate the radiation protection SCA at the McClean Lake Operation as satisfactory. In 2017 the CNSC changed the rating to fully satisfactory based on the results of compliance inspections, desktop reviews and the determination that the radiological hazard control, worker dose control and ALARA programs were highly effective. CNSC staff continue to rate the radiation protection SCA as fully satisfactory based on the result of compliance verification activities carried out in 2018.

McClean Lake Operation - radiation protection ratings
2014 2015 2016 2017 2018
SA SA SA FS FS
FS = fully satisfactory SA = satisfactory

The source of radiological exposure at the McClean Lake Operation is the milling of high-grade uranium ore received from Cameco’s Cigar Lake mine. The three primary dose contributors are gamma radiation (33%), radon progeny (RnP) (41%) and long-lived radioactive dust (LLRD) (26%). Gamma radiation hazards are controlled through practices related to the effective use of time, distance and shielding. Effective doses to nuclear energy workers (NEWs) from exposures to radon progeny and LLRD are controlled through the effective use of source control, ventilation, contamination control and personal protective equipment (PPE).

Orano has incorporated specific radiation protection features into its design to process undiluted, high-grade uranium ore at McClean Lake. These design features were established to limit radiological hazards (for all types) to specific design hazard objectives. Orano continues to implement a comprehensive monitoring program for all hazards to confirm that the engineered control of hazards remains effective, verify that design hazard objectives continue to be met and identify opportunities for improvement at the McClean Lake Operation.

CNSC staff concluded that Orano continues to implement a comprehensive monitoring program and that this program remains highly effective at controlling all radiological hazards at McClean Lake in 2018.

In 2018, there were no exceedances of action levels at the McClean Lake Operation. The radiation protection program and practices continued to effectively maintain worker doses ALARA.

#### Application of ALARA

In 2018, collective radiation exposure to NEWs at the McClean Lake Operation was 296 person-millisieverts (p-mSv), a 3.6 percent decrease from the 2017 value of 307 p‑mSv (figure 7.3) and a decrease of 44 percent from 529 p‑mSv in 2016.

The collective dose values are a reflection of new and existing ALARA initiatives that were implemented at the McClean Lake Operation. These include, but are not limited to:

• cleaning or flushing of equipment prior to maintenance activities
• incorporating shielding material during maintenance activities
• suppressing dust with water
• performing routine cleaning of radiation area equipment and vehicles
• performing maintenance work away from radioactive source materials when practical
• incorporating shielding material in heavy equipment (e.g., haul trucks and loader)
• holding quarterly dose-trending information sessions with workers
• performing routine maintenance of building ventilation and containment control equipment, such as fans, furnaces and doors

Through reviews of radiation monitoring, exposure reports and inspections, CNSC staff confirmed that the radiation protection program was highly effective and ensured that worker exposures remained ALARA in 2018.

#### Worker dose control

Overall, doses remained consistent from 2017 to 2018, with 69 percent of annual effective doses remaining below 1.0 mSv in both years. The average individual effective dose to NEWs in 2018 was 0.90 mSv, while the maximum individual effective dose received by a NEW was 5.50 mSv. These values compare to an average individual effective dose of 0.91 mSv and a maximum individual dose of 5.12 mSv in 2017. All individual effective doses were well below the 50 mSv annual regulatory limit and the 100 mSv limit in a five-year dosimetry period.

In 2018, Orano continued to set more challenging dose targets for workers in higher dose categories:

• average effective dose for top 10 NEWs (5.00 mSv, down from 5.50 mSv in 2017)
• average ore dust target for top 10 NEWs (2.00 mSv, down from 2.25 mSv in 2017)
• average RnP dose target for top 10 NEWs (1.10 mSv, down from 1.30 mSv in 2017)

The first two targets were met. The third target (RnP) was not met, but it was still lower than the 2017 target of 1.30 mSv.

Based on their compliance verification activities, such as inspections, reviews of licensee reports and work practices, and the monitoring of results and individual effective dose results in 2018, CNSC staff were satisfied that Orano controlled radiation doses to workers. CNSC staff concluded that the worker dose control measures at the McClean Lake Operation were highly effective; consequently, they rated Orano’s performance for the radiation protection SCA as fully satisfactory in 2018.

### 7.3 Environmental protection

For 2018, CNSC staff continued to rate the environmental protection SCA as satisfactory based on regulatory oversight activities. CNSC staff concluded that the licensee’s environmental protection program was effectively implemented and met all regulatory requirements.

McClean Lake Operation - environmental protection ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

#### Environmental management system

The environmental management system at the McClean Lake Operation includes activities such as establishing annual environmental objectives, goals and targets. Orano conducts internal audits of its environmental management program at the McClean Lake Operation, as identified in their CNSC-approved management system program. CNSC staff review and assess the objectives, goals and targets through regular compliance verification activities. CNSC staff noted that Orano continued with routine inspections, internal audits, environmental training and periodic reviews of environmental monitoring data. These activities were conducted to ensure continual improvement and to confirm that the controls put into place to protect the environment are effective.

#### Effluent and emissions control

Effluent and emissions monitoring programs serve to demonstrate that the facility’s emissions, wastes, tailings and effluent discharges of nuclear and hazardous substances are properly controlled at the McClean Lake Operation.

##### Treated effluent released to the environment

At the McClean Lake Operation, two effluent streams are processed in separate treatment facilities before being released to the environment:

• The mill effluent is processed at the JEB water treatment plant with a treatment system of chemical precipitation and liquid/solid separation. Treated water is released to the Sink/Vulture treated effluent management system.
• The Sue water treatment plant treats effluent which is pumped to control the water level from the mined-out open pits using a chemical precipitation and settling pond clarification process. This effluent is then released to the Sink/Vulture treated effluent management system.

The blended treated effluent is released in a controlled manner.

The 2016 Environmental Risk Assessment identified future potential risks to aquatic organisms in McClean Lake east due to exposure to selenium from the milling of Cigar Lake ore. In the Regulatory Oversight Report for Uranium Mines, Mills, Historic and Decommissioned Sites in Canada: 2017, CNSC staff reported on the selenium adaptive management plan developed and implemented by Orano. There was no administrative or action level exceedance of selenium concentrations in the JEB water treatment plant effluent in 2018. CNSC staff continue to review reported selenium concentrations in effluent through quarterly reports to ensure the receiving environment remains protected.

Orano submitted a selenium review and assessment report in July 2018. This report provided a technical evaluation of operating performance with implemented process improvements, the feasibility of potentially augmenting selenium removal technologies and selenium risks in the environment. CNSC staff reviewed the report and provided comments, including recommendations for modifying the environmental monitoring program.

One action level and one discharge limit exceedance of the total suspended solids (TSS) concentration from the JEB water treatment plant effluent were reported to CNSC staff. The follow-up report for the discharge limit exceedance indicated that the reportable TSS result was due to a delay in sample analysis that allowed calcium sulphate to precipitate out in the sample container, and the TSS released in effluent did not exceed the regulatory limit. CNSC staff reviewed the event notifications and the follow-up reports, and they were satisfied with the corrective actions implemented by the McClean Lake Operation. See appendix J for additional details on both the regulatory limit exceedance and the action level report.

Orano analyzed treated effluent for concentrations of various substances such as radium‑226, arsenic, copper, lead, nickel, zinc and TSS, and it verified pH levels at McClean Lake. As discussed in section 2.4, the McClean Lake Operation continued to meet the discharge limits set out in the Metal and Diamond Mining Effluent Regulations (MDMER) [5].

CNSC staff will continue to review results on the quality of effluent in order to ensure that the treatment of effluent remains effective.

##### Air emissions released to the environment

Air quality at the McClean Lake Operation is monitored directly by measuring emissions from the mill and the ambient air quality near the operation, and indirectly by measuring metal accumulations in the terrestrial environment.

Air quality monitoring at the McClean Lake Operation includes ambient radon, total suspended particulate (TSP), sulphur dioxide and exhaust stack monitoring. Ambient sulphur dioxide and exhaust stack monitoring were commensurate with the mill commissioning activities and restart in September 2014. Terrestrial monitoring components include soil and vegetation sampling.

Environmental monitoring for radon concentrations is conducted using the passive method of track etch cups. There are 23 monitoring stations in various locations around the site-lease boundary. Figure 7.4 shows the average concentrations of radon in ambient air from 2014 to 2018. Ambient radon concentrations were typical of the northern Saskatchewan regional background concentration of less than 7.4 Bq/m3 to 25 Bq/m3. The measured radon concentrations were also below the reference radon concentration of 55 Bq/m3, which is equal to an incremental dose of 1 mSv per year above background.

Five high-volume air samplers monitor TSP and are located at the McClean Lake Operation. As shown in table 7.2, TSP values remained low in 2018 and well below the provincial standard of 60 µg/m3.

TSP samples were also analyzed for concentrations of metals and radionuclides. The mean concentrations of metal and radionuclides adsorbed to TSP were low and below the reference annual air quality levels identified in table 7.2.

Table 7.2: McClean Lake Operation concentrations of metal and radionuclides in air, 2014–18
Parameter Reference annual air quality levels* 2014 2015 2016 2017 2018
TSP (µg/m3) 60 (3) 5.66 8.37 5.12 4.96 8.00
As (µg/m3) 0.06 (1) 0.000420 0.003070 0.000032 0.000432 0.000354
Cu (µg/m3) 9.6 (1) 0.013888 0.019630 0.021613 0.017159 0.018107
Mo (µg/m3) 23 (1) 0.000721 0.000892 0.000145 0.001028 0.001154
Ni (µg/m3) 0.04 (1) 0.000420 0.000247 0.000259 0.000321 0.000262
Pb (µg/m3) 0.10 (1) 0.000501 0.000368 0.000762 0.000406 0.000417
Zn (µg/m3) 23 (1) 0.005939 0.005452 0.004703 0.003165 0.004684
Pb-210 (Bq/m3) 0.021 (2) 0.000277 0.000271 0.000285 0.000309 0.000253
Po-210 (Bq/m3) 0.028 (2) 0.000088 0.000083 0.000087 0.000100 0.000087
Ra-226 (Bq/m3) 0.013 (2) 0.000010 0.000008 0.000009 0.000014 0.000022
Th-230 (Bq/m3) 0.0085 (2) 0.000005 0.000005 0.000005 0.000006 0.000004
U (µg/m3) 0.06 (1) 0.000576 0.001319 0.003138 0.002029 0.001654

1 Reference annual air quality levels are derived from Ontario 24-hour Ambient Air Quality Criteria (2012).

2 Reference level is derived from International Commission of Radiological Protection (ICRP) Publication 96,
Protecting People Against Radiation Exposure in the Event of a Radiological Attack.

3 Saskatchewan Environmental Quality Guidelines, Table 20: Saskatchewan Ambient Air Quality Standards.
Values are calculated as geometric means.

* Reference levels based on Province of Ontario ambient air quality criteria and are shown for reference only.
No federal or Saskatchewan provincial limits were established at the time of this report.

A sulphur dioxide monitor is used during operations to continuously measure ambient sulphur dioxide concentrations associated with mill emissions. The monitor is located approximately 200 metres downwind of the sulphuric acid plant stack. The measured sulphur dioxide monitoring data (see figure 7.5) showed no exceedances of the annual standard of 20 µg/m3 in 2018.

Orano’s terrestrial monitoring program at McClean Lake determines whether any impact on the environment arises from aerial deposition. Soil and terrestrial vegetation may be affected by the atmospheric deposition of particulate and adsorbed metals and radionuclides associated with onsite activities. This program includes measurements of metals and radionuclides in soil and vegetation. Terrestrial monitoring was conducted in 2018 and the results will be included in the 2021 environmental performance report (EPR).

Soil monitoring results from soil samples collected in 2015 are presented in the 2016 EPR. The results show that the soil metal parameter concentrations were below the Canadian Environmental Quality Guidelines [8] set by the Canadian Council of Ministers of the Environment. Radionuclide concentrations in soils were near or at background levels and analytical detection limits. CNSC staff concluded that the level of airborne particulate contaminants produced by the McClean Lake Operation is acceptable and does not pose a risk to the environment.

Vegetation sampling was also presented in the 2016 EPR and shows that most parameters are within the range of concentrations previously measured in lichen, Labrador tea and blueberry twig samples. The concentrations of metals and radionuclides in lichen, Labrador tea and blueberry twigs were higher than background concentrations for some samples located in the immediate vicinity of mining activities, although the concentrations decreased within a short distance. Overall, the results indicated that the McClean Lake Operation has had a localized effect on the vegetation in areas of activity.

These higher concentrations were below levels that are toxic to plants, and they decreased to within background concentrations at a short distance from the facility. Therefore, no changes are predicted to terrestrial habitat, both within and outside the facility boundary. The elevated concentrations of contaminants within the facility boundary were modelled in an ERA, and no adverse effects were predicted for terrestrial non-human biota.

CNSC staff concluded that the level of airborne particulate contaminants produced by the McClean Lake Operation was acceptable and did not pose a risk to browse (twigs and Labrador tea) and lichen consumers, such as caribou.

#### Uncontrolled releases

In 2018, six events reported to CNSC staff were identified as releases of hazardous substances to the environment:

• On June 23, 2018, a 150-kilogram discharge of molten sulphur to the ground occurred at the sulphur unloading location due to a mechanical failure of the rear trailer valve of the delivery truck.
• On July 19, 2018, while washing out the sulphuric acid plant stack, the drain became blocked causing the water to build up inside the stack. When the drain line was cleared, approximately 0.655 m3 of wash water leaked onto the mill terrace.
• On July 26, 2018, a hydrovac truck was removing water from the north surface access borehole recovery extraction (SABRE) clarification pond. The operator noticed that mine water was leaking onto the ground from the rear door seal. An initial investigation revealed that the box liner in the truck had become detached and prevented the rear door from sealing properly. Approximately 2 m3 of mine water were released to the ground.
• On August 25, 2018, during a routine pond inspection at the Sue site runoff pond, water was detected under the pond liner. Approximately 25 m3 of water was removed from under the liner.
• On September 29, 2018, the calciner scrubber had scale buildup that dislodged and plugged the cone of the scrubber body. The scrubber solution backed up through the scrubber body up to the fan which released material onto the mill terrace. It was determined that approximately 50 grams of calcined yellowcake was released to the mill terrace.
• On December 22, 2018, an Orano employee discovered an anhydrous ammonia drip coming from an offload valve that was not fully closed. It is estimated that approximately 60 litres of liquid anhydrous ammonia was released to the ground.

All spills were of low safety significance and reporting met the requirements of REGDOC‑3.2.1, Public Information and Disclosure [2]. Appendix I describes the spills and the corrective actions taken. As a result of the actions taken by Orano, no residual impacts to the environment were caused by the spills. CNSC staff were satisfied with the reporting of releases of hazardous materials to the environment and the corrective actions taken. CNSC staff rated all the 2018 spills as being of low significance.

Figure 2.12 in section 2 shows the number of reportable environmental spills that occurred at the McClean Lake Operation from 2014 to 2018.

#### Assessment and monitoring

CNSC staff confirmed that the licensee successfully carried out required environmental monitoring, in accordance with the McClean Lake environmental protection program.

Based on compliance activities and the review of annual reports and the environmental protection technical information document, CNSC staff concluded that the environmental monitoring conducted at the McClean Lake Operation met regulatory requirements. Consequently, CNSC staff concluded that the environment remains protected.

#### Environmental risk assessment

The McClean Lake Operation’s environmental protection technical information document was submitted to the CNSC in 2016; it contained environmental monitoring data from 2011 to 2015 and an updated ERA. CNSC staff reviewed the environmental monitoring results for air, soil, vegetation, water, groundwater and sediment, as well as the health indicators for fish and their prey inhabiting sediment, and confirmed that the results were within those predicted in the ERA, with the exception of the predicted short-term exposure of aquatic organisms to selenium in the McClean Lake east basin, which is considered an exposure lake. As stated previously, the 2016 ERA noted a potential future risk to aquatic organisms in McClean Lake east due to selenium releases in effluent. Orano submitted a selenium review and assessment report in July 2018. This report provided a technical evaluation of operating performance with implemented process improvements, the feasibility of potentially augmenting selenium removal technologies and selenium risks in the environment. This was discussed in more detail at the December 2018 Commission meeting on the Regulatory Oversight Report for Uranium Mines, Mills, Historic and Decommissioned Sites in Canada: 2017. CNSC staff are satisfied that Orano continues to appropriately assess the risk to the aquatic environment due to selenium effluent releases and it continues to ensure that selenium effluent releases remain at levels that will ensure the protection of aquatic organisms in the McClean Lake east basin.

After reviewing the environmental protection technical information document and Orano’s ongoing activities to ensure the protection of the environment from selenium releases, CNSC staff concluded that adequate measures have been taken at the McClean Lake Operation to protect the environment.

#### Protection of the public

Orano is required to demonstrate that the health and safety of the public are protected from exposures to hazardous substances released from the McClean Lake Operation. The effluent and environmental monitoring programs currently conducted by the licensee are used to verify that releases of hazardous substances do not result in environmental concentrations that may affect public health.

The CNSC receives reports of discharges to the environment through the reporting requirements outlined in the licence and licence conditions handbook. The review of Orano’s hazardous (non-radiological) discharges to the environment at McClean Lake in 2018 indicated that the public and environment were protected. CNSC staff confirmed the environmental concentrations in the vicinity of the McClean Lake Operation remained within those predicted in the 2016 ERA, and that human health remained protected.

Based on compliance verification activities that included inspections, reviews of licensee reports and work practices, and monitoring results for 2018, CNSC staff concluded that the McClean Lake Operation’s environmental protection program continued to be effective at protecting the public and the environment.

### 7.4 Conventional health and safety

For 2018, CNSC staff continued to rate the conventional health and safety SCA as satisfactory based on regulatory oversight activities.

McClean Lake Operation - conventional health and safety ratings
2014 2015 2016 2017 2018
SA SA SA SA SA
SA = satisfactory

#### Practices

As required under the NSCA [1], Orano continued to improve performance and maintain health and safety programs at the McClean Lake Operation to minimize occupational health and safety risks. CNSC staff confirmed that Orano had an effective occupational health and safety committee and that it was completing regular reviews of its safety program at McClean Lake.

Orano’s McClean Lake Operation investigates safety concerns and incidents, including near-miss events. In 2018, several investigations were completed using the cause mapping process to determine the cause of incidents, near misses, injuries or property damage. This methodology employs a collaborative effort to identify a problem, analyze its causes and determine the best solutions. CNSC staff reviewed the investigation results and corrective actions and confirmed Orano’s commitment to accident prevention and safety awareness with a focus on safety culture.

#### Performance

Table 7.3 shows that from 2014 to 2018, Orano’s McClean Lake Operation reported 10 lost-time injuries (LTIs). One LTI was reported in 2018.

An incident occurred on January 26, 2018, where a worker slipped and fell on icy ground (same elevation). Additional information regarding this LTI can be found in appendix K.

Included in this report is the total recordable incident rate (TRIR) for the last three years. The TRIR is the incident frequency rate that measures the number of fatalities, lost-time injuries and other injuries requiring medical treatment.

2014 2015 2016 2017 2018 3 3 3 0 1 4.3 27.7 10.9 67.8 4.8 0.4 0.4 0.6 0.0 0.3 --- --- 2.9 1.4 0.75 1 An injury that takes place at work and results in the worker being unable to return to work for a period of time. 2 A measure of the total number of days lost to injury for every 200,000 person-hours worked at the facility. Accident severity rate = [(# of days lost in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 3 A measure of the number of LTIs for every 200,000 person-hours worked at the facility. Accident frequency rate = [(# of injuries in last 12 months) / (# of hours worked in last 12 months)] x 200,000. 4 A measure of the number of fatalities, lost-time injuries and other injuries requiring medical treatment for every 200,000 person-hours worked at the facility. Recordable incident rate = [(# of incidents in last 12 months) /(# of hours worked in last 12 months)] x 200,000.

Corrective actions, where necessary, were implemented and their the effectiveness was verified and documented by management. Details on the 2018 LTI and corrective actions are included in appendix J. CNSC staff verified that Orano strives to involve all levels of its organization in the health and safety program at the McClean Lake Operation. Employees are encouraged and trained to continuously identify and assess risks, and propose solutions.

#### Awareness

CNSC staff observed that conventional health and safety programs provided education, training, tools and support to ensure worker protection at the McClean Lake Operation. An active onsite occupational health and safety committee completes regular reviews of the McClean Lake safety program. Through inspections, reviews of incidents and discussions with McClean Lake staff, CNSC staff verified that the McClean Lake Operation is committed to accident prevention and safety awareness. CNSC staff’s compliance verification activities concluded that the McClean Lake Operation’s health and safety program met regulatory requirements in 2018.

## Appendix A: Licence and Licence Conditions Handbook(s)

A.1 Uranium mines and mills licence information
Licensee/site/licence number Licence effective Last licence amendment Licence expiration

McClean Lake Operation

Uranium mine and mill operating licence

UMOL-MINEMILL-McCLEAN.01/2027

July 1, 2017 July 17, 2018 June 30, 2027

Cameco Corporation

Cigar Lake Operation

Uranium mine operating licence

UML-MINE-CIGAR.00/2021

July 1, 2013 - June 30, 2021

Cameco Corporation

Key Lake Operation

Uranium mill operating licence

UMLOL-MILL-KEY.00/2023

November 1, 2013 - October 31, 2023

Cameco Corporation

Rabbit Lake Operation

Uranium mine and mill operating licence

UMOL-MINEMILL-RABBIT.00/2023

November 1, 2013 - October 31, 2023

Cameco Corporation

McArthur River Operation

Uranium mine operating licence

UMOL-MINE-McARTHUR.00/2023

November 1, 2013 - October 31, 2023
A.2 Uranium mines and mills licence conditions handbook changes, 2018
Record of the issuance of licence conditions handbook (LCH)
Licensee/site/licence number LCH revision Summary of changes Effective date of LCH

McClean Lake Operation

Uranium mine and mill operating licence

UMOL-MINEMILL-McCLEAN.01/2027

4

No changes
in 2018

October 6, 2017

Cameco Corporation

Cigar Lake Operation

Uranium mine operating licence

UML-MINE-CIGAR.00/2021

1

No changes
in 2018

January 23, 2014

Cameco Corporation

Key Lake Operation

Uranium mill operating licence

UMLOL-MILL-KEY.00/2023

1

No changes
in 2018

December 15, 2014

Cameco Corporation

Rabbit Lake Operation

Uranium mine and mill operating licence

UMOL-MINEMILL-RABBIT.00/2023

0

No changes
in 2018

January 23, 2014

Cameco Corporation

McArthur River Operation

Uranium mine operating licence

UMOL-MINE-McARTHUR.00/2023

1

No changes
in 2018

April 22, 2014

## Appendix B: List of Inspections

B.1 Inspections by facility and safety and control area
Facility Safety and control area Inspection report issued
Cigar Lake Operation Management system, radiation protection, conventional health and safety, fitness for service, environmental protection March 22, 2018
Fitness for service, conventional health and safety April 5, 2018
Conventional health and safety May 18, 2018
Environmental protection August 27, 2018
Waste management November 5, 2018
Packaging and transport January 11, 2019
McArthur River Operation Fitness for service, conventional health and safety, environmental protection, human performance management March 20, 2018
Environmental protection, radiation protection, conventional health and safety October 31, 2018
Physical design, environmental protection, radiation protection, conventional health and safety August 8, 2018
Environmental protection October 2, 2018
Emergency management and fire protection January 16, 2019
Rabbit Lake Operation Environmental protection, conventional health and safety, radiation protection April 23, 2018
Management system August 17, 2018
Environmental protection, conventional health and safety, radiation protection, operating performance October 11, 2018
Management system, fitness for service, safety analysis, radiation protection, conventional health and safety, emergency management and fire protection May 18, 2019
Key Lake Operation Physical design, conventional health and safety, radiation protection March 20, 2018
Operating performance, safety analysis, conventional health and safety, radiation protection, human performance management, waste management, security May 15, 2018
Environmental protection, conventional health and safety, radiation protection December 21, 2018
Safety analysis, environmental protection, conventional health and safety, radiation protection July 31, 2018
Environmental protection, conventional health and safety, emergency management and fire protection January 3, 2019
McClean Lake Operation Human performance management, operating performance, fitness for service, packaging and transport April 10, 2018
Safety analysis, environmental protection, radiation protection, conventional health and safety, waste management November 5, 2018
Waste management November 20, 2018
Conventional health and safety December 18, 2018
Operating performance January 21, 2019
Conventional health and safety, radiation protection, human performance management January 31, 2019

## Appendix C: Safety and Control Area Definitions

The CNSC evaluates how well licensees meet regulatory requirements and CNSC performance expectations for programs in 14 safety and control areas (SCAs). The SCAs are grouped into three functional areas: management, facility and equipment, and core control processes. The SCA definition for conventional health and safety has been updated.

Table C-1: Safety and Control Area Framework
Functional area Safety and control area Definition Specific areas
Management Management system Covers the framework that establishes the processes and programs required to ensure an organization achieves its safety objectives, continuously monitors its performance against these objectives and fosters a healthy safety culture.
• Management system
• Organization
• Performance assessment, improvement and management review
• Operating experience (OPEX)
• Change management
• Safety culture
• Configuration management
• Records management
• Management of contractors
Human performance management Covers activities that enable effective human performance through the development and implementation of processes that ensure a sufficient number of licensee personnel are in all relevant job areas and have the necessary knowledge, skills, procedures and tools in place to safely carry out their duties.
• Human performance program
• Personnel training
• Personnel certification
• Initial certification examinations and requalification tests
• Work organization and job design
• Fitness for duty
Operating performance Includes an overall review of the conduct of the licensed activities and the activities that enable effective performance.
• Procedures
• Reporting and trending
• Outage management performance
• Safe operating envelope
• Severe accident management and recovery
• Accident management and recovery
Facility and equipment Safety analysis Covers maintenance of the safety analysis that supports the overall safety case for the facility. Safety analysis is a systematic evaluation of the potential hazards associated with the conduct of a proposed activity or facility and considers the effectiveness of preventive measures and strategies in reducing the effects of such hazards.
• Deterministic safety analysis
• Hazard analysis
• Probabilistic safety analysis
• Criticality safety
• Severe accident analysis
• Management of safety issues (including R&D programs)
Physical design Relates to activities that impact the ability of structures, systems and components to meet and maintain their design basis, given new information arising over time and taking changes in the external environment into account.
• Design governance
• Site characterization
• Facility design
• Structure design
• System design
• Component design
Fitness for service Covers activities that impact the physical condition of structures, systems and components to ensure that they remain effective over time. This area includes programs that ensure all equipment is available to perform its intended design function when called upon to do so.
• Equipment fitness for service/equipment performance
• Maintenance
• Structural integrity
• Aging management
• Chemistry control
• Periodic inspection and testing
Core control processes Radiation protection Covers the implementation of a radiation protection program in accordance with the Radiation Protection Regulations [4]. The program must ensure that contamination levels and radiation doses received by individuals are monitored, controlled and maintained ALARA.
• Application of ALARA
• Worker dose control
• Estimated dose to public
Conventional health and safety The implementation of a program to manage workplace safety hazards and to protect workers.
• Performance
• Practices
• Awareness
Environmental protection Covers programs that identify, control and monitor all releases of radioactive and hazardous substances and the effects on the environment from facilities or as the result of licensed activities.
• Effluent and emissions control (releases)
• Environmental management system (EMS)
• Assessment and monitoring
• Protection of the public
• Environmental risk assessment
Emergency management and fire protection Covers emergency plans and emergency preparedness programs that exist for emergencies and for non-routine conditions. This area also includes any results of participation in exercises.
• Conventional emergency preparedness and response
• Nuclear emergency preparedness and response
• Fire emergency preparedness and response
Waste management Covers internal waste-related programs that form part of the facility's operations, up to the point where the waste is removed from the facility to a separate waste management facility. This area also covers the planning for decommissioning.
• Waste characterization
• Waste minimization
• Waste management practices
• Decommissioning plans
Security Covers the programs required to implement and support the security requirements stipulated in the regulations, the licence, orders, or expectations for the facility or activity.
• Facilities and equipment
• Response arrangements
• Security practices
• Drills and exercises
Safeguards and non-proliferation Covers the programs and activities required for the successful implementation of the obligations arising from the Canada/International Atomic Energy Agency (IAEA) safeguards agreements, as well as all other measures arising from the Treaty on the Non-Proliferation of Nuclear Weapons.
• Nuclear material accountancy and control
• Access and assistance to the IAEA
• Safeguards equipment, containment and surveillance
• Import and export
Packaging and transport Programs that cover the safe packaging and transport of nuclear substances to and from the licensed facility.
• Package design and maintenance
• Packaging and transport
• Registration for use

Other matters of regulatory interest

• Environmental assessment
• CNSC consultation - Indigenous
• CNSC consultation - other
• Cost recovery
• Financial guarantees
• Improvement plans and significant future activities
• Nuclear liability insurance

## Appendix D: Safety and Control Area Rating Definitions

Performance ratings used in this report are defined as follows:

Fully satisfactory (FS)

Safety and control measures implemented by the licensee are highly effective. In addition, compliance with regulatory requirements is fully satisfactory, and compliance within the safety and control area or specific area exceeds requirements and Canadian Nuclear Safety Commission (CNSC) expectations. Overall, compliance is stable or improving, and any problems or issues that arise are promptly addressed.

Satisfactory (SA)

Safety and control measures implemented by the licensee are sufficiently effective. In addition, compliance with regulatory requirements is satisfactory. Compliance within the safety and control area or specific area meets requirements and CNSC expectations. Any deviation is only minor, and any issues are considered to pose a low risk to the achievement of regulatory objectives and the CNSC’s expectations. Appropriate improvements are planned.

Below expectations (BE)

Safety and control measures implemented by the licensee are marginally ineffective. In addition, compliance with regulatory requirements falls below expectations. Compliance within the safety and control area or specific area deviates from requirements or CNSC expectations to the extent that there is a moderate risk of ultimate failure to comply. Improvements are required to address identified weaknesses. The licensee or applicant is taking appropriate corrective action.

Unacceptable (UA)

Safety and control measures implemented by the licensee are significantly ineffective. In addition, compliance with regulatory requirements is unacceptable and is seriously compromised. Compliance within the overall safety and control area or specific area is significantly below requirements or CNSC expectations or there is evidence of overall non-compliance. Without corrective action, there is a high probability that the deficiencies will lead to an unreasonable risk. Issues are not being addressed effectively, no appropriate corrective measures have been taken, and no alternative plan of action has been provided. Immediate action is required.

## Appendix E: Safety and Control Area Ratings

Table E-1: Safety and control area ratings for Cigar Lake Operation, 2014–18
Safety and control areas 2014 2015 2016 2017 2018
Management system SA SA SA SA SA
Human performance management SA SA SA SA SA
Operating performance SA SA SA SA SA
Safety analysis SA SA SA SA SA
Physical design SA SA SA SA SA
Fitness for service SA SA SA SA SA
Radiation protection SA SA SA SA SA
Conventional health and safety SA SA SA SA SA
Environmental protection SA SA SA SA SA
Emergency management and fire protection SA SA SA SA SA
Waste management SA SA SA SA SA
Security SA SA SA SA SA
Safeguards and non-proliferation SA SA SA SA SA
Packaging and transport SA SA SA SA SA
Table E-2: Safety and control area ratings for McArthur River Operation, 2014–18
Safety and control areas 2014 2015 2016 2017 2018
Management system SA SA SA SA SA
Human performance management SA SA SA SA SA
Operating performance SA SA SA SA SA
Safety analysis SA SA SA SA SA
Physical design SA SA SA SA SA
Fitness for service SA SA SA SA SA
Radiation protection SA SA SA SA SA
Conventional health and safety SA SA SA SA SA
Environmental protection SA SA SA SA SA
Emergency management and fire protection SA SA SA SA SA
Waste management SA SA SA SA SA
Security SA SA SA SA SA
Safeguards and non-proliferation SA SA SA SA SA
Packaging and transport SA SA SA SA SA
Table E-3: Safety and control area ratings for Rabbit Lake Operation, 2014–18
Safety and control areas 2014 2015 2016 2017 2018
Management system SA SA SA SA SA
Human performance management SA SA SA SA SA
Operating performance SA SA SA SA SA
Safety analysis SA SA SA SA SA
Physical design SA SA SA SA SA
Fitness for service SA SA SA SA SA
Radiation protection SA SA SA SA SA
Conventional health and safety SA SA SA SA SA
Environmental protection SA SA SA SA SA
Emergency management and fire protection SA SA SA SA SA
Waste management SA SA SA SA SA
Security SA SA SA SA SA
Safeguards and non-proliferation SA SA SA SA SA
Packaging and transport SA SA SA SA SA
Table E-4: Safety and control area ratings for Key Lake Operation, 2014–18
Safety and control areas 2014 2015 2016 2017 2018
Management system SA SA SA SA SA
Human performance management SA SA SA SA SA
Operating performance SA SA SA SA SA
Safety analysis SA SA SA SA SA
Physical design SA SA SA SA SA
Fitness for service SA SA SA SA SA
Radiation protection SA SA SA SA SA
Conventional health and safety SA SA SA SA SA
Environmental protection SA SA SA SA SA
Emergency management and fire protection SA SA SA SA SA
Waste management SA SA SA SA SA
Security SA SA SA SA SA
Safeguards and non-proliferation SA SA SA SA SA
Packaging and transport SA SA SA SA SA
Table E-5: Safety and control area ratings for McClean Lake Operation, 2014–18
Safety and control areas 2014 2015 2016 2017 2018
Management system SA SA SA SA SA
Human performance management SA SA SA SA SA
Operating performance SA SA SA SA SA
Safety analysis SA SA SA SA SA
Physical design SA SA SA SA SA
Fitness for service SA SA SA SA SA
Radiation protection SA SA SA FS FS
Conventional health and safety SA SA SA SA SA
Environmental protection SA SA SA SA SA
Emergency management and fire protection SA SA SA SA SA
Waste management SA SA SA SA SA
Security SA SA SA SA SA
Safeguards and non-proliferation SA SA SA SA SA
Packaging and transport SA SA SA SA SA

## Appendix F: Financial Guarantees

The following table outlines the financial guarantees as of December 31, 2018, for the five uranium mine and mill facilities.

Table F-1: Uranium mines and mills financial guarantees
Cigar Lake Operation $49,200,000 McArthur River Operation$48,400,000
Rabbit Lake Operation $202,700,000 Key Lake Operation$218,300,000
McClean Lake Operation $107,241,000 Total$625,841,000

## Appendix G: Worker Dose Data

Table G-1 shows the total number of nuclear energy workers (NEWs) monitored at each of the five uranium mines and mills for 2018. An individual who is required to work with a nuclear substance or in a nuclear industry is designated as an NEW if he or she has a reasonable probability of receiving an individual effective dose greater than the prescribed effective dose limit for a member of the public (i.e., 1 millisievert (mSv) in a calendar year).

Cigar Lake McArthur River Rabbit Lake Key Lake McClean Lake 824 595 166 481 330

The following table compares the average and maximum individual effective dose for all five uranium mines and mills.

Table G-2: Radiation dose data for NEWs at uranium mines and mills, 2018
Facility Average individual effective dose (mSv/year) Maximum individual effective dose (mSv/year) Regulatory limit
Cigar Lake Operation 0.47 7.28 50 mSv/year
McArthur River Operation 0.15 2.67
Rabbit Lake Operation 0.46 1.70
Key Lake Operation 0.19 2.02
McClean Lake Operation 0.90 5.50

Tables G-3 to G-7 show the five-year trend (from 2014 to 2018) for the average and maximum effective annual doses to NEWs at the five uranium mines and mills. Each of these tables also identifies the maximum five-year dose to an individual NEW at each uranium mine and mill. No radiation dose at any facility exceeded the regulatory effective dose limit in 2018.

Table G-3: Radiation dose data for NEWs at Cigar Lake Operation, 2014-18
Dose data 2014 2015 2016 2017 2018 Regulatory limit
Total NEWs 1,458 1,222 1,243 1,107 824 N/A
Average individual effective dose (mSv) 0.16 0.45 0.39 0.34 0.47 50 mSv/year
Maximum individual effective dose (mSv) 2.04 5.99 5.53 3.36 7.28 50 mSv/year
Maximum dose for an individual in current 5-year period (mSv) 2016-20 13.6 100 mSv/5-year dosimetry period
Table G-4: Radiation dose data for NEWs at McArthur River Operation, 2014-18
Dose data 2014 2015 2016 2017 2018 Regulatory limit
Total NEWs 1,149 1,360 1,064 958 595 N/A
Average individual effective dose (mSv) 1.03 1.00 0.85 0.79 0.15 50 mSv/year
Maximum individual effective dose (mSv) 7.91 7.40 7.02 5.73 2.67 50 mSv/year
Maximum dose for an individual in current 5-year period (mSv) 2016-20 12.2 100 mSv/5-year dosimetry period
Table G-5: Radiation dose data for NEWs at Rabbit Lake Operation, 2014-18
Dose data 2014 2015 2016 2017 2018 Regulatory limit
Total NEWs 964 958 739 153 166 N/A
Average individual effective dose (mSv) 1.35 1.36 0.85 0.4 0.46 50 mSv/year
Maximum individual effective dose (mSv) 8.84 9.14 4.95 1.56 1.7 50 mSv/year
Maximum dose for an individual in current 5-year period (mSv) 2016-20 6.24 100 mSv/5-year dosimetry period
Table G-6: Radiation dose data for NEWs at Key Lake Operation, 2014-18
Dose data 2014 2015 2016 2017 2018 Regulatory limit
Total NEWs 1,170 1,191 837 684 481 N/A
Average individual effective dose (mSv) 0.63 0.55 0.62 0.66 0.19 50 mSv/year
Maximum individual effective dose (mSv) 6.21 7.56 5.37 5.39 2.02 50 mSv/year
Maximum dose for an individual in current 5-year period (mSv) 2016-20 11.2 100 mSv/5-year dosimetry period
Table G-7: Radiation dose data for NEWs at McClean Lake Operation, 2014-18
Dose data 2014 2015 2016 2017 2018 Regulatory limit
Total NEWs 894 508 510 334 330 N/A
Average individual effective dose (mSv) 0.37 0.89 1.04 0.91 0.90 50 mSv/year
Maximum individual effective dose (mSv) 2.03 5.28 6.94 5.12 5.50 50 mSv/year
Maximum dose for an individual in current 5-year period (mSv) 2016-20 14.69 100 mSv/5-year dosimetry period

## Appendix H: Exceedances of Radiological Action Levels Reported to the CNSC

Canadian Nuclear Safety Commission (CNSC) staff reviewed and were satisfied with the remedial actions taken by the licensees for the radiological action level exceedances reporting in table H‑1. Table H-1 notes the details of each event, the corrective actions taken by the licensee and the CNSC’s associated significance ratings. Table H-2 lists the rating definitions and examples of safety significance across fuel cycle facilities.

Table H-1: Uranium mines and mills, exceedances of radiological action levels in 2018
Facility Action level exceedance Corrective action Significance rating
Cigar Lake Operation On August 8, 2018, Cameco staff reported that a June 2018 personal alpha dosimeter (PAD) result exceeded 1 mSv in a week. The analysis of June and July PAD results showed that four workers exceeded a weekly action level of 1 mSv per week, with effective doses of 1.18, 1.63, 1.48, and 1.12 mSv. One of the four workers also exceeded the quarterly action level of 5 mSv per quarter, with an effective dose of 5.17 mSv. The event occurred during a project initiated to replace the medium-pressure pumps on the 500 m level of the Cigar Lake mine. While the wash down process has been an effective control in the past, an investigation determined that the dust material present on the piping and electrical cables in this specific area was a clay-based material. While visually it seemed that the wash-down of the material was effective, a portion of the material actually stuck to the piping and electrical cables when it was combined with the water due to the clay content. This clay-based material that was left behind is the source of the exposure that resulted in the action level exceedances for the four workers.

Operating, maintenance and radiation protection personnel received information to assist in properly identifying hazards associated with the clay-type material when working on piping, cable trays or other similar infrastructure that has the potential to lead to similar circumstances as those in this event.

The appropriate operating, maintenance and radiation protection processes will be reviewed and revised to ensure that when work is required where this type of hazard may exist (e.g., pipe replacement), quantitative verification that the potential dust hazard has been mitigated will be obtained before work begins.

When work is required where this hazard may exist, and it is confirmed through a quantitative verification that it cannot be mitigated through normally effective means (washing), other controls, such as respiratory protection, will be put in place before work begins.

CNSC staff conducted a review of this event and the associated corrective actions as part of a reactive inspection conducted in August 2019.

Medium
Cigar Lake Operation In January 2019, Cameco reported November personal alpha dosimeter (PAD) results for a worker whose exposure exceeded 1 mSv in a week. It was also confirmed that the worker’s exposure exceeded the quarterly action level of 5 mSv. A review of the documented work activities indicates that the unusual exposure most likely occurred on November 14, 2018. On this date, the worker and another employee were involved in replacing the preventer flush tube on JBS No. 4. The exposure occurred when the JBS was in standby mode during the mining of a cavity. As a result, the workers did not recognize the need to close the ball valve that would be used to isolate the preventer from the preventer flush tube before the work began on the flush tube. It is likely that the combination of not closing the ball valve and the worker’s position at the opening of the flush tube resulted in the individual receiving the exposure. The investigation identified that the change in the timing of the work on the preventer flush tube from the normal timing (between cavities) to the timing of this event (while on standby during a cavity) resulted in the presence of a hazard not normally inherent in the completion of this work.

Procedures for conducting maintenance on the JBS during an active cavity cycle were reviewed and revised as necessary to ensure that mitigating the risk of potential exposure to radon progeny is addressed, where appropriate. Operations, maintenance and radiation personnel will be apprised of the procedures noted above in order to help them recognize when additional controls are necessary to mitigate this type of risk.

CNSC staff conducted a reactive inspection in August 2019 following the review of investigation reports submitted by the licensee.

Medium
McArthur River Operation None reported N/A N/A
Rabbit Lake Operation None reported N/A N/A
Key Lake Operation None reported N/A N/A
McClean Lake Operation None reported N/A

N/A

Table H-2: CNSC radiation protection rating definitions and examples
Safety significance Definition Fuel cycle facility, specific examples
High

Exposures to multiple workers in excess of regulatory limits.

Widespread contamination to several persons or to a place.

Incident that results in or has reasonable potential for a worker to exceed regulatory limits.

Examples:

• nuclear energy worker (NEW) exceeding 50 mSv/year or 100 mSv/five years
• non-NEW exceeding 1 mSv
Medium

Exposure to a worker in excess of regulatory limits.

An incident that would result in a licensee exceeding an action level.

Limited contamination that could affect a few persons or a limited area.

Incident that results in or has reasonable potential to exceed an action level.

Example:

• doses to workers of 1 mSv/week or 5 mSv/quarter
Low

Increased dose below reportable limits.

Contamination that could affect a worker.

Incident that results in, or has reasonable potential to exceed, the highest administrative level.

## Appendix I: Reportable Releases to the Environment (spills) and CNSC Rating Definitions

Canadian Nuclear Safety Commission (CNSC) staff reviewed and were satisfied with the remedial actions taken by the licensees in response to the spills presented in table I-1 and concluded that these spills resulted in no residual impacts to the environment. Table I-1 notes the details of each spill, the corrective actions taken by the licensee and the CNSC’s spill significance ratings. Table I-2 lists the spill rating definitions and gives examples of safety significance across fuel cycle facilities.

Table I-1: Uranium mines and mills, reportable releases to the environment, 2018
Facility Details Corrective actions Significance rating
Cigar Lake Operation On January 24, 2018, a decreasing trend in the level of treated effluent in monitoring pond "D" was observed. The instrumentation was functioning properly and it was determined that approximately 1,200 m3 of treated effluent had been lost. Surface ice can develop in ponds during the winter period. This ice can create tears in pond liners when the pond level rises or falls during normal operation. Monitoring pond D was locked out and remained locked out until repairs to the liner were made on June 11, 2018. Low
Cigar Lake Operation On February 26, 2018, a freeze plant operator was conducting routine rounds and noticed a faint smell of ammonia. A purge valve on the condenser of Freeze Plant No.2 was observed to be weeping. Approximately 100 millilitres were released to the snow outside the plant. The probable cause of this leak is a failed o-ring within the auto-purge valve assembly. The defective valve was repaired and the plant returned to service. Affected snow was removed and placed in the freeze plant sump. Low
Cigar Lake Operation On April 12, 2018, a freeze plant operator was conducting routine rounds and determined that a solenoid was leaking ammonia. 9.2 kilograms of ammonia were released. A purge point on solenoid #4 at condenser #2 of Freeze Plant No. was determined to be the source of the leak. It was determined that the probable cause of this leak is a worn teflon seal in the solenoid valve. The valve was taken out of service until maintenance was completed. Low
Cigar Lake Operation On June 22, 2018, primary freeze plant No.2 was being restarted following a power outage when ammonia was found to be leaking from a flanged connection to a knife-gate valve located above the heat exchanger. An approximate total of under 40 kilograms of ammonia were released to the atmosphere. The probable cause of the leak is a gasket failure. A refrigeration mechanic made repairs to the valve. Low
Cigar Lake Operation

On September 9, 2018, primary freeze plant No.2 was being restarted following a power outage. A knife-gate valve used to isolate heat exchangers in the plant was found to be leaking. 0.1 kilogram of ammonia was released. The seal on the knife-gate valve operates under negative pressure when the plant is running normally. This seal may have been worn prior to this event, but the negative pressure conditions kept all ammonia inside the system. When the plant restarted, the momentary increase in pressure allowed ammonia to leak past the seal.

Approximately 4 ounces of ammonia were released to the atmosphere.

The leak was stopped and maintenance work to repair the system was completed. Low
McArthur River Operation On August 6, 2018, an inspection of treated effluent monitoring ponds 3 and 4 revealed that temporary repairs completed in May 2018 had failed, and it was estimated that approximately 8,000 m3 of treated water had been discharged from these ponds. There was no effect on the environment or the health and safety of personnel. The ponds were repaired. The procedure for pond liner repairs was reviewed with all personnel performing the work, and an internal investigation completed. Low
McArthur River Operation On August 25, 2018, a mechanic entered module 1 of the freeze plant and noticed a slight smell of ammonia. The mechanic determined that a small amount of ammonia had been released from a cracked vessel sight glass. The exact amount of ammonia released is unknown, but none of the ammonia detectors in the plant displayed elevated concentrations of ammonia during this event. There was no effect on the environment or the health and safety of personnel. A refrigeration mechanic isolated, purged then repaired the vessel. Low
Rabbit Lake Operation At approximately 4:00 p.m. on July 22, 2018, a discharge of liquid propane was reported when two Safety Department employees were inspecting an area near the 68,100 L propane tank that feeds the sand dryer and dry shotcrete plant at the Eagle Point mine. The employees noticed frost buildup on a valve on the liquid side of the line feeding the tank for the offload point. The employees assessed the situation and approached the valve from a safe direction. Upon reaching the valve, the employees noted an audible hiss and a small amount of liquid propane visibly leaking from the tank. After confirming the presence of the leak, the employees immediately triggered emergency shutoff valves on all lines connected to the tank and retreated to a safe distance to allow residual propane to dissipate. With the tank isolated immediately and no occupied building within 100 m of the tank, this was not considered an emergency situation. Once it was confirmed that the area was clear, the Rabbit Lake Environment department arrived and completed a visual site inspection. The tank has been repaired. Low
Key Lake Operation

On May 2, 2018, an intermittent leak was discovered coming from two manual valves on the #2 ammonia storage tank vapour line by the Solvent Extraction Facility.

No release volume could be estimated due to the intermittent nature of the leaks. However, there was no measurable change in the tank levels as a result of the leaks, which indicates that the release volume was relatively minor.

Subsequent to discovering the initial leaks, maintenance personnel completed an inspection and exercised each valve on all three ammonia storage tanks. During this process, some minor leaks were discovered on four additional valves: one valve on tank #1, one more valve on tank #2 and two valves on tank #3. These additional four valves were not leaking before the maintenance team exercised them. The maintenance team continued to work on these valves and were able to stop all of the leaks.

CNSC staff verified the status of the ammonia tank upgrade project as part of a compliance inspection.

Low
Key Lake Operation

On June 29, 2018, during an area inspection, mill operations found a valve leaking on ammonia storage tank #1.

No release volume could be estimated; however, there was no measurable change in the tank level as a result of the leak, which indicates that the release volume was relatively minor.

The area was secured using danger tape to prevent unauthorized access to the ammonia storage tank area. The requirement to use respiratory protection when in the area was implemented. The valve was sealed and gas testing was completed to confirm that the leak had stopped.

CNSC staff verified the status of the ammonia tank upgrade project as part of a compliance inspection.

Low
Key Lake Operation On July 24, 2018, during an inspection of the fire suppression system valves, it was discovered that the low-pressure carbon dioxide system level had dropped significantly in the storage tank. This occurred sometime within a two-week period. Approximately 170 kilograms of carbon dioxide were released.

The area was secured to prevent unauthorized access. The storage tank was drained, repaired and inspected.

The area was inspected by CNSC staff in a follow-up to the event and the corrective actions were considered to be satisfactory.

Low
Key Lake Operation On November 22, 2018, a propane leak was detected coming from a two-inch plug near the two-inch Fisher valve at the reverse osmosis propane tank. The release volume was very small and therefore cannot be estimated; however, the leak duration was in excess of 10 minutes.

A plumber and safety officer inspected and tightened the plug which stopped the leak. This was confirmed with gas monitoring.

The event was reviewed at the site-wide safety meeting and a site safety flash was issued to workers on the importance of reporting any smell of propane. A daily walk-down inspection is completed of all propane systems.

The tank and valving were inspected during a CNSC inspection in a follow-up to the event and the corrective actions were considered to be satisfactory.

Low
Key Lake Operation

In December 2018, Cameco reported an increase in uranium concentrations in groundwater well MT-802 after a review of the groundwater data. The elevated concentrations date back to June 2018.

Follow-up samples were collected from this well and others in the area. The samples confirmed the increasing trend in uranium concentration in MT‑802. The investigation indicates the likely source was sump #2 in the molybdenum extraction building.

An initial event report (IER) was discussed at a Commission meeting on May 15, 2019.

Cameco’s actions to date include:

• reporting the spill
• investigating the source
• removing the source (water drained within the building sump areas)
• ensuring that radiation protection measures were implemented within the building
• increasing groundwater monitoring of the well and surrounding wells to confirm that the area of elevated uranium remains isolated
• developing an investigation plan

The investigation into the elevated uranium in a monitoring well is being undertaken. Cameco has been providing updates on the status of the investigation to CNSC staff, the province of Saskatchewan and local stakeholders/Indigenous groups. In addition, a complete assessment report will be developed and submitted in early 2020. The assessment is being completed in accordance with both federal and provincial requirements. The installation of monitoring wells and soil sampling was completed in the summer of 2019 and water quality and soil samples are being analyzed. Although the investigation is not complete, the results to date continue to indicate that the elevated uranium is limited to the immediate area and there remains no risk to the surrounding environment. Once the assessment report is complete, this will be used to develop a corrective action plan.

Low
McClean Lake Operation On June 23, 2018, 150 kg of molten sulphur was spilled from a truck at the sulphur unloading location following the mechanical failure of the rear trailer valve. In response, the offloading procedure has been updated to require that the offloading hose be connected before starting the steaming process. This change will ensure containment if any issues are encountered with the truck valves. Low
McClean Lake Operation On July 19, 2018, while washing out the sulphuric acid plant stack, the drain became blocked causing the water to build up inside the stack. When the drain line was cleared, approximately 0.655 m3 of wash water leaked onto the mill terrace in a localized area immediately outside the sulphuric acid plant.

The work to wash the stack was stopped immediately. The discharge area was barricaded to prevent anyone from entering the area.

The liquid was collected and transported to the tailings neutralization facility for disposal. The impacted soil on the surface of the mill terrace was removed. Approximately 6 m3 of affected soil was collected for landfill disposal. The ground was sampled after the affected soil was removed to ensure a complete cleanup.

Low
McClean Lake Operation On July 26, 2018, a hydrovac truck was removing water from the north SABRE clarification pond. The operator noticed that mine water was leaking onto the ground from the rear door seal. An initial investigation revealed that the box liner in the truck had become detached and prevented the rear door from sealing properly. Approximately 2 m3 of mine water was released. The ponded water was disposed of in the Sue pre-sedimentation ponds to be treated, and the affected soil was scraped up and taken to the contaminated landfill for disposal. Soil samples were collected post cleanup. The results showed that the post-cleanup soil chemistry was similar to the baseline soil chemistry. In the future, hydrovac operators will perform a visual inspection of the rear door seal prior to pumping and inspect the bed liner and fasteners routinely during use. Low
McClean Lake Operation On August 25, 2018, during a routine pond inspection at the Sue site runoff pond, water was detected under the pond liner. Approximately 25 m3 of water was removed from under the liner. Primary source of the water was likely due to the 1 in 500 year 24 hour storm event that occurred over July 14-15, 2018. Furthermore, the water level in the pond exceeded the 1 m freeboard level during the storm event, which would have allowed water to flow through a failed patch. The water sample results showed elevated concentrations of radium-226 (22.4 Bq/L) and uranium (1.42 mg/L). The water under the liner was removed using a vacuum truck and the liner was repaired. Low
McClean Lake Operation On September 29, 2018, the calciner scrubber had scale build-up that dislodged and plugged the cone of the scrubber body. The scrubber solution backed up through the scrubber body and up to the fan, which released material onto the mill terrace, the adjacent buildings and equipment for approximately four minutes before it shut down. A small amount of additional material was released when the fan restarted two hours later. The material that exited the calciner stack was sampled and the majority (>90%) was determined to be ammonia sulphate crystal mixed with a small amount of calcined yellowcake. A release of 50 grams of calcined yellowcake meets the recordable radiological release criteria for reporting a radiological release. Although the total quantity released is difficult to estimate, it was determined to be >50 grams. When the fan shut down, the feed to the calciner was also shut down and the blockage in the scrubber was cleared prior to restarting. The area where the material was deposited was barricaded. All affected snow, buildings and equipment were cleaned up, and all contaminated material was disposed of on the JEB ore pad. Low
McClean Lake Operation On December 22, 2018, an Orano employee discovered an anhydrous ammonia drip coming from an offload valve that was not fully closed. An estimated 60 litres were released. The employee contacted the area operator; they donned full face respirators and obtained personal ammonia monitors, then barricaded the immediate area. The area operator closed the offload valve immediately after discovering the leak. The free product was then scraped up with a loader and disposed of in the hydrocarbon landfarm. Low
Table I-2: CNSC environmental protection spill rating definitions and examples
Environmental protection
Safety significance Definition Fuel cycle facility-specific examples
High Nuclear or hazardous substances being released to the environment exceeding regulatory limits (including public exposure) or that results in significant impact to the environment.

Incident that results in, or has reasonable potential to have, a significant or moderate impact or extensive future remediation.

Examples:

• impairment of ecosystem functions
• effluent licence limit exceedance
• spill into fish bearing water
• fish kill
Medium Nuclear or hazardous substances being released to the environment exceeding action levels (including public exposure) or that result in impact to the environment outside the licensing basis.

Incident that results in, or has reasonable potential to have, a minor impact or that requires some future remediation.

Examples:

• effluent action level exceedance
• spills to environment (including atmosphere) with short-term or seasonal impacts
Low Release of hazardous or nuclear substances to the environment below regulatory limits.

Incident that results in, or has reasonable potential to have, a negligible impact.

Examples:

• spills to environment (including atmosphere) with no future impacts

## Appendix J: Environmental Action Level and Regulatory Limit Exceedances Reported to the CNSC

Canadian Nuclear Safety Commission (CNSC) staff reviewed and were satisfied with the corrective actions taken by the licensees for the environmental action level and regulatory exceedances reported in table J-1. Table J-1 notes the details of each event, the corrective actions taken by licensees and the CNSC’s associated significance ratings. Table J-2 lists the rating definitions and examples of safety significance across fuel cycle facilities.

Table J-1: Uranium mines and mills, environmental action level exceedances, 2018
Facility Action level or regulatory limit exceedance Corrective action Significance rating
Cigar Lake Operation None reported N/A N/A
McArthur River Operation

On March 9, 2018, Cameco reported three administrative level exceedances for radium (0.30 Bq/l). On March 10, 2018, Cameco notified CNSC staff of an action level exceedance (average concentration of a constituent in 10 ponds exceeds an administrative level) for radium. These exceedances were identified during a routine duplicate-sample analysis. The duplicate sample analyzed by the Saskatchewan Research Council indicated it contained higher radium concentrations than the duplicate sample analyzed by the McArthur River Operation sample.

As a result of the McArthur River facility’s transition from operating to care and maintenance status, uranium ore production stopped at the McArthur River Operation. This caused a change in the chemistry of the influent and the amount of reagent necessary to bring the water to concentrations necessary for release. The change in the volume of reagent used to account for the change in influent chemistry resulted in excess reagent remaining in the effluent, which suppressed the radium analysis result. Since the exceedance, Cameco has adjusted its treatment methodology, and radium concentrations in effluent have been restored to historical levels. The authorized limit (0.37 Bq/L) under the Metal Diamond Mining Effluent Regulations was not exceeded as a result of this incident.

McArthur River Operation relied on Key Lake laboratory results for pond release until the McArthur River analysis issue for radium was resolved.

McArthur River increased its frequency of sampling in receiving waters and concluded that no increase in radium concentrations was evident.

McArthur River carried out a statistical analysis to establish a radium level where an archived sample was not available. All raw data and derived concentrations were submitted to the CNSC for review.

Cameco adjusted the analytical methodology at the McArthur River lab to include the pre-treatment of the samples to remove any potential for the suppression of radium-226 during the analysis.

Cameco has resolved the issue, and no impact on the environment or health and safety of persons resulted from this action level exceedance.

Medium
Rabbit Lake Operation None reported N/A N/A
Key Lake Operation There were no environmental action level exceedances at the Key Lake Operation; however, one event occurred in which approximately 10 m3 of high pH (10.16) effluent was released from the reverse osmosis treatment plant on October 12, 2018, before the effluent discharge was stopped. Although only a small volume of water was released, the pH was above the upper pH limit specified in the Metal and Diamond Mining Effluent Regulations (9.5). The average daily discharge of treated effluent to the environment in the month of October 2018 was approximately 14,860 m3. An investigation was completed by Cameco, and corrective actions were developed and implemented to improve pH monitoring and control. Cameco’s implementation of corrective actions was assessed by CNSC staff, and it was found to be acceptable. There was no impact to the environment as a result of the incident. Low
McClean Lake Operation

On May 11, 2018, Orano reported that a grab sample of effluent collected at the final discharge point at 7:00 a.m. on March 6, 2018, exceeded the regulatory limit for TSS. This is a routine grab sample, collected quarterly. The sample was submitted to an offsite laboratory for analysis. The results of the sample analysis indicated a TSS of 268 mg/L. Under the MDMER [5], the McClean Lake licence conditions handbook (Section 9.2) and the Saskatchewan Ministry of Environment Approval to Operate PO17-186, the maximum authorized concentration of TSS in a grab sample is 30 mg/L.

On March 12, 2018, when the unpreserved portion of the sample was analyzed, the laboratory noted that a large amount of visible white particulate had settled on the bottom of the sample bottle and it became suspended when shaken.

A review of the grab sample analysis indicated that the concentration of calcium was the highest that has been measured in a grab sample from this final discharge point since effluent was first released in 1996, and the concentration of sulphate was also higher than most previous grab samples. With the time lag between the collection of the grab sample and its analysis, combined with significant temperature changes during transportation and storage, it is very likely that the solubility of the gypsum was reduced in the sample bottle, causing it to precipitate out of solution.

In order to ensure that future sample analyses are representative of the effluent deposited, the analyzing laboratory has agreed to treat TSS analysis in effluent as time critical.

CNSC staff are satisfied with the corrective actions implemented. CNSC staff determined that the reported event did not constitute a release of effluent, because the sample was not representative of the actual release to the environment. Therefore, there was no exceedance of the action level or regulatory limit.

High – changed to Low

CNSC staff determined that the reported event did not constitute a release of effluent, because the sample was not representative of the actual release to the environment. Therefore there was no exceedance of the action level or regulatory limit.

McClean Lake Operation On March 3, 2018, Orano reported that the 24-hour discharge sample from the JEB WTP had a TSS concentration of 15 mg/L. The action level in the Environmental Code of Practice  is 12 mg/L. When the valves were turned to switch between ponds being discharged, scale and rust were dislodged, entering the sample line. The solution was to remove the sample line while the ponds were being switched over. Medium
Table J-2: CNSC environmental protection rating definitions and examples
Environmental protection
Safety significance Definition Fuel cycle facility-specific examples
High Nuclear or hazardous substances being released to the environment exceeding regulatory limits (including public exposure) or that results in significant impact to the environment.

Incident that results in, or has reasonable potential to have, a significant or moderate impact or extensive future remediation.

Examples:

• impairment of ecosystem functions
• effluent licence limit exceedance
• spill into fish bearing water
• fish kill
Medium Nuclear or hazardous substances being released to the environment exceeding action levels (including public exposure) or that result in impact to the environment outside the licensing basis.

Incident that results in, or has reasonable potential to have, a minor impact or that requires some future remediation.

Examples:

• effluent action level exceedance
• spills to environment (including atmosphere) with short-term or seasonal impacts
Low Release of hazardous or nuclear substances to the environment below regulatory limits.

Incident that results in, or has reasonable potential to have, a negligible impact.

Examples:

• spills to environment (including atmosphere) with no future impacts

## Appendix K: Lost-time injuries

A lost-time injury (LTI) is a workplace injury that results in the worker being unable to return to work for a period of time. Table K-1 outlines the LTIs reported in the 2018 reporting period at the five uranium mines and mills. Table K-2 lists the rating definitions.

Table K-1: Uranium mines and mills, lost-time injuries (LTIs), 2018
Facility Incident Corrective action Significance rating
Cigar Lake Operation No LTIs were reported N/A N/A
McArthur River Operation No LTIs were reported N/A N/A
Rabbit Lake Operation No LTIs were reported N/A N/A
Key Lake Operation No LTIs were reported N/A N/A
McClean Lake Operation An incident occurred on January 26, 2018, where a worker slipped and fell on icy ground (same elevation). A worker parked a light duty vehicle. As the driver stepped out of vehicle, he lost his footing on the snow-packed icy surface and fell to the ground. While trying to break his fall, the driver extended his arm. He injured his left wrist, shoulder and lower back. The worker was wearing all required PPE footwear. The area had large amounts of ice build-up. Immediate corrective actions included removing the snow build up and sanding the area. The McClean Lake Operation has sand readily available at all exits for employees to use. In addition, high traffic areas around the site are sanded on a regular basis. Medium
Table K-2: CNSC conventional health and safety rating definitions
Safety significance Definition
High Fatality or serious injury
Medium Serious injury or lost-time accident
Low Minor injury

## Appendix L: Annual Releases of Radionuclides to the Environment

### Introduction

Uranium mines and mills in northern Saskatchewan have process waters which need to be captured, treated and released through a final point of control. This appendix covers the total annual release of relevant radionuclides from these facilities from 2014 to 2018.

This appendix includes details on releases of radionuclides of interest, those in the natural uranium decay series, specifically total uranium and uranium‑238 progeny. Total uranium as a metal is the contaminant of interest, rather than specific uranium isotopes, because uranium is more chemically toxic than radiologically toxic. The primary uranium-238 progeny of interest are alpha emitters with half-lives (> 10 days) long enough for them to participate in environmental and biological uptake processes of relevance to low dose chronic exposures. This includes the following radionuclides: thorium-230, radium-226, lead-210 and polonium-210. Uranium-234, with a half-life of 24,600 years, is accounted for in the total uranium category.

Releases for total uranium are reported in kilograms (kg), while releases of uranium U‑238 progeny are reported in megabecquerels (MBq).

Table L.1: Total annual load of uranium (kg) and relevant uranium-238 progeny (MBq) released in liquid effluent to surface waters from the northern Saskatchewan uranium mines and mills, from 2014 to 2018.
Facility and year Uranium (kg) Thorium-230 (MBq) Radium-226 (MBq) Lead-210 (MBq) Polonium-210 (MBq)
Cigar Lake Mine
2014 6.63 2.00 2.74 8.47 7.57
2015 38.00 3.73 3.13 8.00 10.70
2016 2.36 3.81 2.71 8.69 6.41
2017 0.72 3.27 3.05 9.27 4.86
2018 0.18 3.61 2.33 7.21 9.01
McArthur River Mine - Mine water treatment plant discharge
2014 22.8 22.7 87.4 51.0 92.7
2015 21.2 23.6 152.9 55.9 184.4
2016 12.7 26.7 151.6 51.6 100.5
2017 12.9 24.5 161.5 49.0 96.4
2018 15.7 23.7 150.9 47.3 22.2
McArthur River Mine - Shaft #3 discharge
2014 0.2788 N/A 34.53 N/A N/A
2015 0.0991 N/A 14.26 N/A N/A
2016 0.0762 N/A 10.80 N/A N/A
2017 0.1953 2.14 20.64 4.29 1.07
2018 0.2992 1.18 37.01 2.35 0.59
Rabbit Lake Mine and Mill
2014 199.7 96.7 41.0 96.7 96.7
2015 220.7 84.9 30.0 339.5 106.1
2016 326.9 89.9 32.9 359.6 89.9
2017 274.0 117.0 25.6 311.9 78.0
2018 135.8 84.4 26.4 337.5 84.4
Key Lake Mill - Treated mill effluent discharge
2014 6.0 48.2 53.0 90.7 82.2
2015 7.5 65.8 64.4 75.2 16.4
2016 4.8 77.0 41.7 53.9 15.4
2017 7.3 69.2 61.8 23.8 7.7
2018 17.9 31.5 95.6 27.0 7.3
Key Lake Mill - Reverse osmosis plant discharge
2014 9.39 N/A 20 N/A N/A
2015 13.1 N/A 17 N/A N/A
2016 15.3 N/A 23 N/A N/A
2017 6.5 N/A 23 N/A N/A
2018 8.5 N/A 25 N/A N/A
McClean Lake Mill - Combined release from the JEB and Sue water treatment plants
2014 2.3 12.1 7.2 48.6 13.3
2015 5.5 16.4 10.8 54.5 26.3
2016 6.5 20.2 12.0 122.1 61.3
2017 5.7 18.8 11.7 88.5 30.8
2018 9.9 21.2 13.5 86.1 32.7
Note: <DL means that the loading was reported as less than the detection limits.

## Acronyms and abbreviations

ALARA
as low as reasonably achievable
AREVA
BE
below expectations
Bq/L
becquerels per litre
Bq/m3
becquerels per cubic metre
CMD
Commission member document
CNSC
COPC
contaminants of potential concern
EARMP
Eastern Athabasca Regional Monitoring Program
ECCC
EMS
environmental management system
EQC
environmental quality committee
EPR
environmental protection report
ERA
environmental risk assessments
ENGO
environmental non-governmental organizations
FS
fully satisfactory
HHRA
human health risk assessment
IAEA
International Atomic Energy Agency
IC
incident command
ICMM
International Council on Mining and Metals
ICRP
IER
initial event report
JEB
John Everett Bates
Kg
kilograms
LCH
licence conditions handbook
LLRD
LTI
lost-time injury
mASL
metres above sea level
Mkg
million kilograms
MBq
megabecquerels
MDMER
Metal and Diamond Mining Effluent Regulations
mg/L
milligram per litre
MMER
Metal Mines Effluent Regulations
mSv
millisievert
NEW
nuclear energy workers
NSCA
Nuclear Safety and Control Act
Orano
p-mSv
person-millisievert
personal alpha dosimeter
PM
preventive maintenance
RnP
SA
satisfactory
SABRE
surface access borehole recovery extraction
SCAs
safety and control area
SO2
sulphur dioxide
SRO
site runoff
TMF
tailings management facility
TRIR
total recordable incident rate
TSP
total suspended particulate
TSS
total suspended solids
UA
unacceptable
WTP
water treatment plant

## References

1. Nuclear Safety and Control Act, S.C. 1997, c. 9.
2. CNSC, REGDOC-3.2.1, Public Information and Disclosure, Ottawa, Canada, 2018.
3. CNSC, REGDOC‑3.2.2, Aboriginal Engagement, 2016.
4. Radiation Protection Regulations (2000), SOR/2000-203.
5. Metal and Diamond Mining Effluent Regulations, SOR/2002-222, 2018.
6. Fisheries Act, R.S.C., 1985.
7. Uranium Mines and Mills Regulations, SOR/2000-206.
8. Canadian Environmental Quality Guidelines, Canadian Council of Ministers of the Environment, 2014.
9. CNSC, REGDOC‑3.6, Glossary of CNSC Terminology, 2016.

## Glossary

For definitions of terms used in this document, see REGDOC‑3.6 Glossary of CNSC Terminology, which includes terms and definitions used in the Nuclear Safety and Control Act (NSCA) and the regulations made under it, and in CNSC regulatory documents and other publications.

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