37th Annual CNS Conference - 2017 June 04-07

Presented at:
37th Annual CNS Conference
2017 June 04-07
Niagara Falls
Session Title:
Plenary II: Safety & Security

Carlos Lorencez (Director of the Nuclear Safety Division, Ontario Power Generation)
Peter Purdy (Division Manager, Reactor Safety Engineering, Bruce Power)


Canadian nuclear utilities regularly and proactively update the nuclear safety analysis for their plants. Such updates were underway at the time of the Fukushima accident in 2011. Fukushima highlighted the importance of multi-unit effects, which are explicitly accounted for in the Probabilistic Safety Analysis (PSA) of multi-unit CANDU stations. Even though the safety analysis and other metrics confirm overall nuclear power plant safety, Fukushima highlighted the need to improve how the overall risk of multiunit nuclear power plants, or the whole-site risk, is documented and demonstrated to be acceptable.

This paper summarizes whole-site risk considerations, including defence in depth, deterministic safety analysis, and PSA, and how multi-unit effects are explicitly taken into account. The paper addresses aggregation of PSA results for multiple reactors in a station, and for different PSA hazard categories. The paper summarizes the integrated approach to demonstrate and document the adequacy of whole-site risk.

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