ASN Report 2022

For the latest information on the subject: asn.fr/l-asn-controle/corrosion-sous-contrainte The Flamanville EPR reactor is also undergoing analysis and checks with regard to this issue. With the technical support of the IRSN, ASN will remain focused on this dossier in 2023 and will closely monitor the results of the checks carried out by EDF. It will examine any EDF strategy changes that could result from this. 1. More than 110 metallurgical expert assessments have been performed in the laboratory, after cutting of the welds on several reactors. Further assessments are to be carried out in order to consolidate the data acquired. 2. The reactors are classified according to their model – or “plant series” – and according to the electrical power they deliver: 900 Megawatts electric (MWe), 1,300 MWe and 1,450 MWe. There are 32 reactors of the 900 MWe type: 4 reactors of the CP0 plant series (4 at Bugey) and 28 reactors of the CPY series (4 at Tricastin, 6 at Gravelines, 4 at Dampierre-en-Burly, 4 at Le Blayais, 4 at Chinon, 4 at Cruas-Meysse and 2 at Saint-Laurent-des-Eaux). The 20 reactors of 1,300 MWe can be subdivided into two plant series: the P4 series with 8 reactors (4 at Paluel, 2 at Saint-Alban and 2 at Flamanville) and the P’4 series with 12 reactors (2 at Belleville-sur-Loire, 4 at Cattenom, 2 at Golfech, 2 at Nogent-sur-Seine and 2 at Penly). There are 4 reactors of the 1,450 MWe type, in the N4 plant series (2 at Chooz and 2 at Civaux). 3. With the exception of those of Cattenom NPP reactor 4, on which the expert assessments carried out in 2022 revealed no stress corrosion cracks. EDF will define the strategy concerning this reactor following the inspections scheduled for 2023. The second half of 2022 was devoted to repairing several reactors and completing the investigations on those most susceptible. This problem justified close monitoring by ASN, in close collaboration with the Institute for Radiation Protection and Nuclear Safety (IRSN), which enabled rapid and informed decisions to be made. ASN considers that the choices made by the licensee are appropriate, whether regarding the reactor outages or the in-depth investigations. ASN considers that EDF acted as a responsible licensee given the safety issues related to the cracks revealed on equipment for which the integrity must be guaranteed. ASN carried out more than 40 dedicated inspections. These inspections notably took place as part of the lines verification or replacement operations in the EDF engineering departments, in the NPPs and at the subcontractors. The High Committee for Transparency and Information on Nuclear Safety (HCTISN), the Local Information Committees (CLIs) and, more broadly, the public – through information meetings and notices – were informed of the important stages of this dossier. ASN held regular discussions with its foreign counterparts, some of whom intend to request inspections on this same subject. The reactors of the French NPP fleet will be inspected using the new inspection system developed by EDF, by the end of 2025. In 2023, EDF will carry out preventive replacement of the areas of interest on the susceptible lines of the P’4(3) type reactors. ABSTRACTS – ASN Report on the state of nuclear safety and radiation protection in France in 2022 13 Notable events 2022 Preparation of the line before installation on the auxiliary system Welding training

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