Canadian Nuclear Safety Commission invites comments on draft REGDOC-2.4.3, Nuclear Criticality Safety

News Release

For immediate release
July 11, 2017 -- Ottawa

The Canadian Nuclear Safety Commission (CNSC) is asking the public to provide comments on draft REGDOC-2.4.3, Nuclear Criticality Safety,  by September 14, 2017. Comments submitted, including names and affiliations, will be made public.

This draft regulatory document is based on RD-327, Nuclear Criticality Safety and GD-327, Guidance for Nuclear Criticality Safety, and has been updated to incorporate changes in certain standards from the American National Standards Institute published by the American Nuclear Society. Where necessary, the text has been adapted to make it applicable to Canada’s international obligations to the International Atomic Energy Agency and consistent with the CNSC’s regulatory requirements.

If approved, REGDOC-2.4.3 will supersede RD-327 and GD-327.

The consultation process includes a request for information specific to this document, which outlines the regulatory objectives and approach, as well as the estimated impacts on stakeholders. The public is asked to provide clear and specific feedback to help CNSC staff refine or revisit initial assumptions and objectives.

To review and comment on the document and the request for information, visit the REGDOC-2.4.3 Web page.

Note: A “tracked changes” version of draft REGDOC-2.4.3, Nuclear Criticality Safety, which indicates where updates and amendments were made, is available upon request to  

The CNSC regulates the use of nuclear energy and materials to protect health, safety and 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.

Quick Facts

  • REGDOC-2.4.3 provides information for preventing criticality accidents in the handling, storage, processing and transportation of fissionable materials and the long-term management of nuclear waste.

  • REGDOC-2.4.3 clarifies the minimum physical constraints and limits on fissionable materials to ensure nuclear criticality safety during the construction, operation, decommissioning or abandonment of the licensed facility.

  • This regulatory document applies to operations with fissionable materials outside nuclear reactors, except for the assembly of these materials under controlled conditions (such as in critical experiments).

  • The CNSC welcomes feedback at any time on regulatory documents.

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Aurèle Gervais

Media Relations

Canadian Nuclear Safety Commission



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