OPTIMIZING MAINTENANCE THROUGH PROBABILISTIC SAFETY ASSESSMENT IN ORDER TO IMPROVE SAFETY

摘要

In 1990 EDF decided to launch a research programme aimed at making optimum use of maintenance resources. The objective of this work is to focus maintenance work on equipment which has a fundamental role in safety and unit availability and the maintenance costs that arise out of these. By taking account of the functional missions of the equipment, and thus being in a position to weight maintenance in accordance with the importance of those missions, the procedure implemented sets out to form part of a broader vision than that of conventional maintenance centred on equipment failures. This approach implies having a good understanding of the functional role of the equipment in order to conduct a rational analysis of its failure modes. Furthermore, it must be based on operating feedback whose analysis helps determine equipment performance relative to those failure modes. Safety requirements are taken into account in the functional study of a system by seeking out the failure modes whose effects induce a significant increase in the core melt risk or initiate an emergency procedure, and the equipment whose unavailability is subject to French technical specifications. Two importance factors obtained from PSAs are used to select the equipment whose failure makes a significant contribution to the risk of core melt.