Summary

Proceedings of a symposium jointly organized with ANS, ENS and OECD/NEA, Vienna, 3-7 June 1991. During recent years the development of PSA has been directed towards its use as a practical tool for the enhancement of operational safety. Only plant specific analysis can provide a basis for meaningful risk management. The importance of human interventions in the recovery from degraded states of operation, the importance of inclusion of external events in PSA, the determination of potentials for common cause failures and the importance of treating and communicating the uncertainties have already been well established within the PSA community. Also, risks during low power level and shutdown states have become more recognized.