RECENT ADVANCES IN DEVELOPING GUIDES AND STANDARDS FOR INTERNAL FLOODING PRA

摘要

The Electric Power Research Institute has sponsored many projects to improve and upgrade the technology for Probabilistic Risk Assessments (PRAs) and associated applications at nuclear power plants as part of their PRA Scope and Quality Program. The focus of this paper is to highlight some recent advances in the development of guides and standards in the evaluation of accident sequences initiated by internal flooding. The topics addressed include the development of guidelines for the performance of a PRA in a manner that meets the technical requirements in the ASME/ANS PRA standard, and the development of a data base of piping system failure rates for use in estimating flood-induced initiating event frequencies. Examples are shown of how these methods and tools have been used to support the evaluation of design, inspection, and surveillance strategies to reduce the risk of internal-flood induced accident sequences. Progress made recently in the enhancement of PRA standards for internal flooding PRA (IFPRA) that take advantage of these developments is also discussed.