Reliability assessment and data processing techniques of the squib valve in pressurized water NPPs

As for the passive PWR NPP, the SV plays a crucial role in nuclear accident mitigation. Since the reliability test of SV is destructive, it is too pricy to perform large sampling of repetitive tests to acquire data. Instead, this paper introduces an economical methodology with small sample tests which is suitable for the SV reliability assessment. Based on the FMEA results, the components of cartridge and mechanical parts are identified as principal contributors and analyzed meticulously. Data processing techniques within the framework of Bayesian inference are developed so as to achieve data format consistency in data aggregation and perform uncertainty analysis by Monte Carlo approach. The main findings of this paper are the practical methodology of assessing the SV reliability and convincing results which solve an issue in the passive PWR NPP safety review.