In Situ Decommissioning of the Whiteshell Reactor #1

Canadian Nuclear Laboratories (CNL) is proposing to decommission the Whiteshell Reactor #1 (WR-1 Reactor), a former nuclear research reactor that operated until 1985. The WR-1 Reactor is located at the Whiteshell Laboratories (WL) site in Pinawa, Manitoba, which is situated approximately 100 kilometres northeast of the city of Winnipeg and located near the towns of Lac du Bonnet and Seven Sisters.

CNL is proposing an in situ (leaving in place) decommissioning approach. In situ decommissioning of the WR-1 Reactor involves preparing systems and structures for grouting whereby the below-grade sealed structure will encapsulate and contain radiological sources and hazardous materials for a defined period of institutional control.

The following activities are being proposed:

  • preparation for in situ decommissioning
  • grouting of below-grade (underground) structures and systems
  • removal of above-grade structures and systems
  • installation of engineered cover over grouted area
  • final site restoration
  • long-term care and maintenance activities

Some temporary infrastructure – such as construction trailers and equipment paddocks, as well as an increase to the electrical services – would also be required in order to facilitate decommissioning. Additional groundwater monitoring wells would be installed, as required, to monitor the performance of the in situ decommissioned facility.

Under the Nuclear Safety and Control Act, CNL's proposal requires an amendment to its existing Decommissioning Waste Facility Licence issued by the Canadian Nuclear Safety Commission (CNSC). An environmental assessment conducted under the Canadian Environmental Assessment Act, 2012 is required, and an EA decision affirming that the proposed activities will not cause significant adverse environmental effects, before the CNSC can make a licensing decision on this proposal.

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Latest update

August 26, 2025 - The Federal Provincial Indigenous Review Team (FPRIT) has completed it’s technical review of CNL’s January 2025 revised draft EIS WR-1 project submission. The links contain the outcome letter from CNSC to CNL, the FPIRT technical review results, and additional feedback and concerns from the FPIRT.   

February 20, 2025 - On January 21, 2025, Canadian Nuclear Laboratories (CNL) submitted a revised draft environmental impact statement (EIS) for the proposed in situ decommissioning of the Whiteshell Reactor #1 Project to the Canadian Nuclear Safety Commission (CNSC). The submission included an updated EIS, updated technical supporting documents, and updated responses to information requests by the federal, provincial, and Indigenous review team. CNSC staff have conducted a completeness check and determined that the outstanding information requests have passed completion, and the supporting submissions are adequate to proceed to the EIS technical review. The federal, provincial, and Indigenous review team will begin a 120-day technical review of CNL’s documentation, beginning on February 20, 2025, and ending no later than June 20, 2025. The draft EIS and supporting documentation can be accessed by visiting All Records, located further down this page.

More information can be found in the February 20, 2025 letter to CNL.

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Key documents

Key documents
Document Number Document Title File Date
112 Environmental Impact Statement - In Situ Decommissioning of WR-1 at the Whiteshell Laboratories Site - Revision 5 PDF (51.6 MB) January 20, 2025
108 May 8, 2023 - Revised Letter from CNSC Staff to CNL with the Outcome of the Revised Draft EIS Technical Review (including findings from Sagkeeng First Nation) PDF (156 KB) May 8, 2023
105 April 27, 2023 - Letter from CNSC staff to CNL with the Outcome of the Revised Draft EIS Technical Review PDF (181 KB) April 27, 2023
104 Letter to Canadian Nuclear Laboratories Ltd. regarding the CNSC extending the technical review period for the revised draft environmental impact statement for the proposed WR-1 In Situ Decommissioning Project PDF (161 KB) February 24, 2023
77 CNSC staff completeness check table of the draft environmental impact statement for the In Situ Decommissioning of the Whiteshell Reactor #1 Project (January 13, 2023) PDF (328 KB) January 13, 2023
76 Letter to Canadian Nuclear Laboratories Ltd. regarding CNSC staff completeness check of the draft environmental impact statement for the In Situ Decommissioning of the Whiteshell Reactor #1 Project (January 13, 2023) PDF (157 KB) January 13, 2023
80 Environmental Impact Statement - In Situ Decommissioning of WR-1 at the Whiteshell Laboratories Site - Revision 4 PDF (43 MB) December 15, 2022
79 Environmental Impact Statement- Executive Summary - In Situ Decommissioning of WR-1 at the Whiteshell Laboratories Site - Revision 4 PDF (1.8 MB) December 15, 2022
74 Letter to Canadian Nuclear Laboratories Ltd. regarding CNSC staff completeness check of the draft environmental impact statement for the In Situ Decommissioning of the Whiteshell Reactor #1 Project (August 24, 2022) PDF (219 KB) August 24, 2022
70 Letter to Canadian Nuclear Laboratories Ltd. Regarding CNSC staff completeness check of the draft environmental impact statement for the In Situ Decommissioning Of the Whiteshell Reactor #1 Project (April 30, 2020) PDF (270 KB) April 30, 2020
58 CNSC Table: Consolidated Public and Indigenous Nations and communities - Comments on the In Situ Decommissioning of the Whiteshell Reactor #1 Draft EIS PDF (216 KB) March 12, 2018
57 CNL Table: Consolidated Public and Indigenous Nations and communities - Comments on the In Situ Decommissioning of the Whiteshell Reactor #1 Draft EIS PDF (1 MB) March 12, 2018
51 Consolidated Table of Federal and Provincial Comments on the Draft Environmental Impact Statement for the In Situ Decommissioning of the Whiteshell Reactor #1 PDF (1.3 MB) December 22, 2017
25 Appendices of the Draft Environmental Impact Statement for the In Situ Decommissioning of the Whiteshell Reactor #1 Project PDF (11.3 MB) October 5, 2017
24 Draft Environmental Impact Statement for the In Situ Decommissioning of the Whiteshell Reactor #1 Project PDF (59.3 MB) October 5, 2017
3 Project Description for In Situ Decommissioning of Whiteshell Reactor #1 PDF (1.2 MB) June 2, 2016

External links

Please note that access to external websites is provided solely as a courtesy. Users should be aware that the information offered by non‑Government of Canada websites that are not subject to the Official Languages Act might be available in only one language.

Contacts

Canadian Nuclear Safety Commission
Aimee Rupert, Environmental Review Specialist
280 Slater Street
Ottawa, Ontario K1P 5S9
Telephone: 613-316-2087 or 1-800-668-5284
Email: wr1@cnsc-ccsn.gc.ca


Disclaimer

This map is for illustrative purposes. The markers represent the approximate locations based on available data. More than one marker may be identified for a given assessment.

  • Location

    • Pinawa (Manitoba)

  • Nature of Activity

    • Nuclear Energy

  • Assessment Status

    In progress

  • Start Date

    2016-05-16

  • Proponent

    Canadian Nuclear Laboratories

  • Authorities

    • Canadian Nuclear Safety Commission

  • Assessment Type

    Environmental assessment under CEAA 2012

  • Reference Number

    80124

Nearby assessments

...within 200 kilometres
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