Whole-Site Risk Considerations for Small Modular Reactors

Abstract

For conventional, large-scale nuclear power plant sites (e.g., multi-unit CANDU stations), risk has traditionally been estimated on a “per reactor, per hazard” basis. In recent relicensing hearings in Canada, and as an ongoing topic of discussion internationally, the issue of whole-site risk has been raised. For OPG’s existing Pickering nuclear site, a whole-site risk assessment was conducted to characterize the overall, site-wide risk associated with: multiple reactor units, all reactor modes of operation, all non-reactor sources of radioactivity (e.g., spent fuel bays), and all internal and external hazards. This paper presents a summary of the Pickering whole-site risk assessment and considers the relevance of the approach in the context of the siting of small modular reactors, whether on a new site or on existing nuclear power plant site.