Statement of the French Safety Authority Concerning the Behaviour of 900 MWe PWR RPV Between 30 and 40 Years in Operation

Abstract

The French 900 MWe reactor pressure vessel (RPV) integrity demonstration was reviewed in 2010 by the French Nuclear Safety Authority (ASN), together with its technical support organisation, the French Institute for Radiation Protection and Nuclear Safety (IRSN). The purpose was to decide whether these 3-loop PWR RPV’s are able to remain in service for ten years after their third decennial outage (VD3). ASN and IRSN examined the demonstration developed by Electricite´ De France (EDF) in order to ensure the compliance of in-service RPV behaviour with regulatory requirements and to check the validity of the calculations and hypotheses that were used for that purpose. The analysis aimed notably at ensuring that the results of every calculation step were conservative and that regulatory safety margins were applied. The calculations made by EDF showed that regulatory criteria were met until the provisional deadline of their fourth decennial outage (VD4). Thus ASN considered that the serviceability of all 900 MWe PWR RPV’s is guaranteed throughout the decade following the VD3 of the reactors, considering that EDF respects ASN demands with a view to comfort safety margins.