Level 1 and Level 2 Internal Events PSA Accident Sequence Quantificationfor Point Lepreau Refurbishment Project

摘要

A Probabilistic Safety Assessment (PSA) for Point Lepreau Generating Station has beenrncompleted as part of the plant Refurbishment Project. The main objective of this PSA is to providerninsights into plant safety design and performance, including the identification of dominant riskrncontributors and comparing options for reducing risk. The scope of this assessment covers Level 1rnand 2 PSA and includes internal events for full power and shutdown, internal fires and internal floodsrnas well as PSA-based seismic events margin for full power operation.rnFor Level 1 Accident Sequence Quantification (ASQ), mitigating system fault trees (FTs) werernmerged into a single FT in order to quantify the event trees for internal events and estimate the severerncore damage frequency. The dominant Level 1 severe core damage sequences were grouped based onrnsimilar core damage progression. For each grouping, severe accident progression analysis wasrnperformed. Using these results, the containment event trees (CETs) were developed. ContainmentrnFTs were merged into the Level 1 FTs to quantify the CETs and estimate the large release frequency.rnThis paper describes the major steps in performing Level 1 and Level 2 ASQ for internal events andrndiscusses the key results of this study.