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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.


Latest update

October 16, 2018 - The timelines in Appendix A of the CNL-CNSC Administrative Protocol for the Renewal of the Whiteshell Laboratories Licence and the Proposed In Situ Decommissioning of the WR-1 Reactor have been updated to clarify the environmental assessment (EA), licensing and public hearing processes for the review of the Whiteshell project. Canadian Nuclear Laboratories (CNL) has indicated that they require additional time 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. Given that there are no firm time commitments for receipt of CNL's completed responses, or for the remainder of the regulatory process, Appendix A has been revised to clarify the milestones remaining in the EA and licensing processes and the current focus of obtaining a complete submission of information. The required timelines for the federal and provincial authorities to complete their reviews remain the same. More information is available here.


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  • Canadian Nuclear Safety Commission
  • 280 Slater Street
  • Ottawa, ON, K1P 5S9
  • Telephone: 613-947-0554 or 1-800-668-5284
  • Fax: 613-995-5086
  • Email:

  • Location

    • Pinawa (Manitoba)
  • Project Type

    • Nuclear and Related Facilities
  • Status

    In progress
  • Start Date

  • Proponent

    Canadian Nuclear Laboratories
  • Authorities

    • Canadian Nuclear Safety Commission
  • Assessment Type

    Environmental assessment under CEAA 2012
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