The Flamanville 3 EPR nuclear plant under construction in France will undergo additional tests following detection of anomalies in the steel in certain parts of the reactor pressure vessel.
AREVA and EDF discovered the anomalies after chemical and mechanical tests were performed on a model of the reactor vessel head and bottom in late 2014. The French Nuclear Safety Authority (ASN) was informed in April that the tests revealed "the presence of a zone in which there was a high carbon concentration, leading to lower than expected mechanical toughness values."
"Initial measurements confirmed the presence of this anomaly in the reactor vessel head and reactor vessel bottom head of the Flamanville EPR," ASN said. The Flamanville 3 RPV was manufactured by AREVA at its Saint Marcel heavy components facility in Burgundy.
A new series of tests will begin this month on the representative vessel head to precisely identify the location of the anomalies and determine the area’s mechanical properties. ASN will make a decision on the acceptability of the test programme, check its correct performance and examine the file to be submitted by AREVA to demonstrate the robustness of the reactor vessel. The French regulator will call on the expertise of the Institute of Radiation Protection and Nuclear Safety (IRSN) and the Advisory Committee of Experts for Nuclear Pressure Equipment during this process.
EDF and AREVA said their teams are working to perform the additional tests as soon as possible "to provide the safety authority with all the necessary information to demonstrate the safety and quality of the corresponding equipment." In parallel, work continues at the 1650MW Flamanville EPR, which is expected to start up in 2017.
ASN also said it has informed foreign regulators who are involved in the construction of EPR reactors. EPRs are currently being built at Olkiluoto 3 in Finland and Taishan 1&2 in China.