Use of Level 1 PSA in the Frame of EPR Licensing

The French “Technical Guidelines for the design and construction of the next generation of NPPs with Pressurized Water Reactors” specify that the safety demonstration has to be achieved in a deterministic way, supplemented by probabilistic methods. In this context, for the EPR reactor of Flamanville (EPR-FA3), the PSA has been used from the beginning of the design. In the frame of the application for commissioning of EPR-FA3, EdF has to provide an “as-build” full scope PSA for the reactor and for the spent fuel pool, covering the internal events, as well as the internal and external hazards of significant impact. Some of these probabilistic studies were developed and evolved during the EPR design (PSA for “internal events”, specific studies for practically eliminated sequences, long term accident sequences…) and were analysed by IRSN, as French Safety Authority (ASN) technical support, at different EPR project stages (initial design, detailed design, construction application….) leading to many design and studies improvements. Today, in order to make the analysis of the application for the commissioning of the EPR-FA3 reactor more effective, the “anticipated” analysis of this application is in progress in France. In this context, the updated versions of the level 1 probabilistic studies for internal events and hazards were analysed by IRSN in 2013. The results and conclusions of this analysis were presented by IRSN early 2014 during a dedicated meeting of French Standing Group of experts for Reactors safety (SGR). The paper presents the analysis performed by IRSN of EdF EPR-FA3 level 1 probabilistic studies, highlighting the role of PSA to the achievement of high level of safety of EPR reactor.