摘要

In seismic PSA of nuclear power plant, the equipment failure probability is affected by two parts response and fragility. In this paper causations of CCF in the above two parts is analyzed, the sensitivity of CCF factor is evaluated under different peak ground acceleration levels. When the peak ground acceleration is much lower than the component seismic resistance capacity, difference between the results of CCF factor beta = 0.05 and beta = 1 is about one magnitude, while the results of beta = 0.05 and beta = 1 are very similar when the peak ground acceleration is close to or even higher than the component seismic resistance capacity. Then a model for system reliability analysis based on Monte Carlo (MC) simulation is proposed: the effect of structure's response can be analyzed in the system reliability model, and the CCF methods used in internal event PSA are also suitable for CCF in response and fragility of the equipment in seismic PSA. The reliability of accumulator system in AP1000 is analyzed as an example under different seismic hazard curves, the system failure probability difference between uncertainties of structure's response beta(S) = 0.1 g and beta(S) = 0.4 g is about one magnitude, and the results of CCF factor of beta = 0.05 and beta = 1 are very similar since the component failure probability is close to 1 when peak ground acceleration is high.