Severe Accident Management at Canadian Nuclear Power Plants (NPPs)

Abstract of the technical presentation presented at:
Cooperative Severe Accident Research Program (CSARP)
June 7-11, 2021

Prepared by: Mohamed Shawkat
Canadian Nuclear Safety Commission


Beyond Design Basis Accidents (BDBAs) in general and severe accidents in particular gained a lot of attention following the Fukushima Daiichi accident in 2011. This presentation provides an overview of the Canadian regulatory framework for management of severe accidents and the Severe Accident Management (SAM) programs implemented at Canadian Nuclear Power Plants (NPPs). The requirements for severe accident management according to Canadian regulatory documents and the progression of the severe accident in CANDU reactors are discussed in detail. The presentation highlights the main challenges that may result in containment failure following a severe accident, the strategies that are implemented to prevent severe accidents, stop or delay their progression until off-site mitigation strategies can be established. The strategy of In-Vessel Retention (IVR) is presented and discussed. IVR minimizes severe accident consequences, including radiological consequences, and its success requires an efficient SAM program that ensures no failure of the Calandria vessel following severe core degradation.

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