OPECST hearing on the anomalies and irregularities detected on nuclear pressure equipment. ASN has reviewed the situations.

On 25^th October 2016, ASN participated in the hearing organised by the  OPECST (Parliamentary Office for the Evaluation of Scientific and Technological Choices) on the safety of nuclear pressure equipment (NPE). The OPECST heard ASN and its technical support agency IRSN, the manufacturer Areva NP, the licensee EDF, and the HCTISN (French High Committee for Transparency and Information on Nuclear Security).

Pierre-Franck Chevet, the ASN Chairman, and Rémy Catteau, Director of nuclear pressure equipment at ASN, presented the anomalies on the reactor pressure vessel upper and lower domes of the Flamanville 3 EPR reactor, similar technical anomalies on the primary lower domes of the steam generators of certain reactors in operation, and the irregularities detected in Areva NP's Creusot Forge plant.

The ASN Chairman underlined the following points:

• Flamanville 3 EPR reactor pressure vessel: ASN has accepted the justification procedure proposed by Areva NP and a mechanical tests programme is in progress. The Areva NP file should be submitted at the end of 2016. After submission, it will be examined by ASN and IRSN, an examination that will take at least 6 months.
• Examination of all the forged components, including those of the steam generators, at ASN's request: the presence of a high carbon concentration, particularly in the primary lower domes fabricated by Japan Casting & Forging Corporation (JCFC) equipping 12 French reactors is confirmed. Inspections have been carried out or are in progress on 7 reactors during scheduled outages. On 18th October, ASN issued a resolution requiring that these inspection be performed on the other 5 reactors within three months. The purpose of these inspections is to verify that the primary lower domes concerned fall within the scope of the hypotheses of the file submitted by EDF. Examination of this file by ASN and IRSN will take a few weeks, perhaps longer if the submitted file requires complementary information.
• Irregularities observed in Areva NP's Creusot Forge plant: these are unacceptable irregularities. ASN has asked for an in-depth review of past practices. The files of all the equipment items manufactured by this plant shall be verified. Areva NP states that this review will take one year. New deviations could be detected. The inspection methods will have to be modified in order to counter practices of this type.

 Pierre-Franck Chevet also emphasized the human and technical resources ASN invests in these matters, and the public information measures to ensure the transparency of the process.