Fukushima Accident Implications on Probabilistic Safety Assessment and on the Licensing of Nuclear Power Plants in Canada

An abstract of the technical paper presented at:
Probabilistic Safety Assessment & Management Conference
Honolulu, Hawaii, U.S.
June 22–27, 2014

Prepared by:
Yolande Akl, Smain Yalaoui
Canadian Nuclear Safety Commission (CNSC)
Ottawa, Ontario, Canada.

Abstract

Following the Fukushima Daiichi accident, the Canadian Nuclear Safety Commission (CNSC) Fukushima Task force made 13 recommendations to further enhance the safety of Canadian nuclear power plants.

Regulatory document S-294, which sets out the requirements for performance of probabilistic safety assessments (PSAs) by licensees, was identified as one of the regulatory documents that requires some amendments to address lessons learned from the Fukushima event. This paper will elaborate on Fukushima-driven amendments made to S-294:

• extension of Level 1 and Level 2 PSA to cover irradiated fuel bay events
• inclusion of external events and their combinations
• multi-unit considerations

This paper will also elaborate on how some existing requirements have been made more specific.

The paper will develop further on issues raised during public hearings, as well as subsequent challenges, especially for those issues related to multi-unit PSA, such as the definition of safety goals per unit year or site year and the aggregation of the PSA results for different initiating events.

Finally, this paper will discuss the technical implications of a new requirement directing a utility to provide a whole-site PSA, or a methodology for a whole-site PSA, as well as an updated PSA that considers requisite Fukushima–driven enhancements. 

To obtain a copy of the abstract’s document, please contact us at cnsc.info.ccsn@cnsc-ccsn.gc.ca or call 613-995-5894 or 1-800-668-5284 (in Canada). When contacting us, please provide the title and date of the abstract.