Draft ASN opinion on the anomaly in the composition of the steel in the bottom and top of the EPR reactor vessel at the Flamanville nuclear power plant (INB no. 167) - Consultation from 09/07/2017 to 12/09/2017

At the end of 2014, Areva NP identified an anomaly in the chemical composition of the steel used in the Flamanville EPR reactor vessel, which could lead to a deterioration in its ability to resist crack propagation. Areva NP launched a test program to demonstrate that the steel's mechanical strength is sufficient in all operating situations, including accidental ones. Areva NP's conclusions were transmitted to ASN in December 2016. On June 28, 2017, ASN presented its position on the Flamanville EPR reactor vessel anomaly. ASN based its position on the analysis of the files transmitted by Areva NP and EDF, carried out by its Nuclear Pressure Equipment Department and IRSN's technical support, and on the opinion of its standing group of experts for nuclear pressure equipment. ASN is making available to the public the investigation report drawn up by ASN and IRSN, and the opinion of its standing group of experts for nuclear pressure equipment. This document brings together all the documents made available to the public for this consultation: 1 - The ASN and IRSN report on the analysis of the consequences of the anomaly in the Flamanville EPR reactor vessel caps on their suitability for service; 2 - the opinion of the standing group of experts for nuclear pressure equipment of June 27, 2017; 3 - the draft ASN opinion submitted for public consultation on the anomaly in the composition of the steel of the vessel base and cover; 4 - The Summary of the public consultation