Level 1 External Events (Internal Fire, Internal Flood and Seismic Events) PSA Accident Sequence Quantification for Point Lepreau Refurbishment Project

摘要

A Probabilistic Safety Assessment (PSA) for Point Lepreau Generating Station has been completed as part of the plant Refurbishment Project. The main objective is to provide insights into plant safety design and performance, including the identification of dominant risk contributors and the comparison of options for reducing risk. The scope of this assessment covers Level 1 and 2 PSA and includes internal events for full power and shutdown, and internal fires, floods, and seismic events for full power operation. Internal fire analysis established potential fire scenarios by identifying their fire characteristics (ignition sources, combustibles, fire protection features, and location of PSA-credited components). The fire-induced severe core damage frequency (SCDF) was estimated for fire scenarios that were not screened out. Internal flood analysis established potential flood scenarios by identifying the flooding source, propagation, and effect on PSA-credited equipment. The flood-induced SCDF was estimated for each flood scenario. PSA-based seismic margin assessment measured the robustness of the plant to withstand earthquakes of a given g-level. This paper describes the major steps in performing Level 1 ASQ for internal fire, flood, and seismic events and discusses the key results of this study.