French R&D Program for RPV Aging Management

Until now French approach for RPV PTS assessment is based on at least 40 years lifetime. This lifetime has been taken into account at each step of the the RPV life: first early in the design, then at each periodic safety demonstration by including the surveillance program, the national and international feedback and R&D results. All of them confirm that all the 3-loop French RPV fulfill the existing criteria for at least 40 years of operation. In order to evaluate their capability to operate for 60 years, an Engineering and Research and Development program has been recently established and engaged by EDF. This large program of activities between all of divisions of EDF is focused on the different fields involved in the risk of fast rupture of the irradiated core vessel. The main purposes of this programme are: • the research of specific data corresponding to a long lifetime of about 60 years; • the studies of new methods to improve the demonstration including several themes such as fluence evaluation, determination of fracture toughness, structural integrity assessment including probabilistic approach, definition of transients; • the evaluation of mitigation methods. This paper contains first a description of what was done at each RPV PTS assessment and an overview of the present program.