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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.


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 project.


Latest update

October 29th, 2019 - In September 2019, the CNL-CNSC Administrative Protocol for the Proposed In Situ Decommissioning of the WR-1 Reactor and Appendix A were updated to reflect the decoupling of the Whiteshell (WL) decommissioning licence renewal from the proposed In Situ Decommissioning of WR-1 Project and now reflects that the hearing for the proposed In Situ Decommissioning of WR-1 will be held in two parts.

CNL is continuing to address information requests (IRs) received on the draft Environmental Impact Statement (EIS) from the federal and provincial authorities as well as from Indigenous groups and members of the public. Once this has been completed, CNL will provide their final submission to the CNSC, including the revised EIS, which will commence the review of CNL's final submission package.

August 28th, 2019 – Canada’s new Impact Assessment Act (IAA) came into force on August 28th, 2019. As per the transition provision described in subsection 182 of the IAA, given that the In Situ Decommissioning of the Whiteshell Reactor #1 (WR-1) Project was commenced under the Canadian Environmental Assessment Act of 2012 and a decision statement has not yet been issued, the Project will continue under it's current process. The letter sent to Canadian Nuclear Laboratories (CNL) regarding the changes to Federal legislation can be found here.


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  • Canadian Nuclear Safety Commission
  • 280 Slater Street
  • Ottawa, ON, K1P 5S9
  • Telephone: 613-943-9920 or 1-800-668-5284
  • Fax: 613-995-5086
  • Email:

  • Location

    • Pinawa (Manitoba)
  • Project Type

    • Nuclear Energy
  • Status

    In progress
  • Start Date

  • Proponent

    Canadian Nuclear Laboratories
  • Authorities

    • Canadian Nuclear Safety Commission
  • Assessment Type

    Environmental assessment under CEAA 2012
  • Reference Number

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