Use of a Graded Approach in Deterministic Safety Analysis for Nuclear Power Plants in Canada

Abstract of the technical paper/presentation presented at:
7th International Workshop on CANDU Safety Association for Sustainability (CANSAS – 2018)
October 15‒18, 2018

Prepared by:
Christopher Harwood
Canadian Nuclear Safety Commission


Canada allows the application of a graded approach to meet regulatory requirements. Grading can be applied to any type of facility or activity and to any Safety and Control Area [these are the topic areas used by CNSC in licensing of nuclear power plants (NPPs) and are based on the topic areas of a periodic safety review. Canada’s approach to grading has already been examined with respect to small modular reactors. However, this presentation focuses on the application of a graded approach to deterministic safety analysis for existing NPPs.

The Nuclear Safety and Control Act is the governing legislation for the Canadian Nuclear Safety Commission (CNSC). The purpose of the Act includes “the limitation, to a reasonable level and in a manner that is consistent with Canada’s international obligations, of the risks to national security, the health and safety of persons and the environment …”. This provides a foundation for consideration of risk, and hence a graded approach, in the regulation of nuclear facilities and activities. Use of a graded approach is in line with international practice, for exampleIAEA GSR Part 1, Governmental, Legal and Regulatory Framework for Safety.

The CNSC is working with stakeholders to develop a strategy for implementation of a graded approach to deterministic safety analysis for nuclear power plants. Principles and guidelines are proposed and will be examined during the presentation.

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