An overview of seismic risk analysis methodology as applied to industry sponsored nuclear PRAs

Experience from the performance of comprehensive probabilistic risk assessment (PRA) studies on nuclear power plants in the USAindicates that the contributions to severe core damage and risk from external events such as earthquakes can be substantial. The purpose of this paper is to give an overview of the seismic PRA methodology, explain the differences between the internal events PRA and the seismic PRA, and finally to discuss the insights gained from the performance and review of a number of seismic PRAs. Based on these insights, the performance of a seismic PRA in order to locate possible weak links in systems and plant design and to address ways of enhancing plant safety, can be justified