Probabilistic Analysis of Containment Overpressure Failure in Level 2 PSA

Abstract

Containment is the final barrier to prevent any leakage and release of radioactive materials. The containment internal pressure may exceed the design value during severe accident, which could threaten the containment integrity. Therefore, the study on fragility and failure probability of containment under accident conditions has become a crucial issue in nuclear safety. In this paper, firstly, the PWR containment failure modes are identified based on relevant researches and engineering practices. Secondly, the containment failure caused by overpressure is divided into the structural failure and functional failure, which are discussed in detail. Finally, combined with both deterministic and probabilistic analysis methodology, fragility curve of PWR containment was evaluated as a step on the evaluation of containment failure probability due to the overpressure in Level 2 PSA.