Regulatory Evaluation of the Mühleberg PSA

Probabilistic Safety Assessment (PSA) is an integral part of the Periodic Safety Review (PSR) in Switzerland. In 2000, the licensee of the Muhleberg nuclear power plant (Kernkraftwerk Muhleberg; KKM) performed a full-scope PSA according to the PSR requirements of the Swiss Federal Nuclear Safety Inspectorate (HSK), consisting of level-1 and level-2 PSAs for full-power operation (Muhleberg Safety Assessment; MUSA2000) and a level-1 PSA for shutdown operation (SMUSA). Level-2 PSAs during non-full power mode of operation, and level-3 PSAs are currently not required in Switzerland. MUSA2000 is an update of the original MUSA study (MUSA90), which was completed in 1990. The present paper describes the HSK review process and the main results and insights gained from the regulatory PSA of KKM.