Research on Probabilistic Safety Assessment at PNC

This paper summarizes the current status on the PSA-related activities at PNC. A special emphasis is placed on the recent progress of development of analytical tools for PSA and PSA application study for LMFBR. The results of the trend analyses which are being performed by CREDO database are described. Brief description of typical systems analysis programs, FAUST, QUEST, LIPSAS, et al., and consequence analysis programs, APPLOHS and CONTAIN are made. This paper also describes the brief overview of the value-impact analysis code, VIA, and the results which indicate the usefulness of the code. PNC is conducting level-3 PSA for a Japanese prototype LMFBR, Monju. A comprehensive systems analysis has been performed to identify and quantify accident sequences which lead to core damage. A quantitative consequence analysis has been performed, where the in-vessel physical processes, containment responses and radionuclide transport for dominant accident sequences, ULOF, UTOP, PLOHS, LORL and ULOHS and their risks were extensively evaluated. The results provide insights on the importance of accident contributors. (author)