On 16 June 2023, an earthquake occurred in the municipality of La Laigne, between La Rochelle and Niort. This earthquake was felt on the NPPs of Civaux, Blayais and Chinon. The intensity of this earthquake did not trigger the reactor building shaking alarms. However, as a precaution, the safety patrols on the installations confirmed that there were no civil engineering anomalies. Risks linked to extreme temperatures The inspections concerning the risks associated with extreme temperatures show that EDF’s organisation must be improved on the majority of sites. On several sites, ASN more particularly found a lack of forward planning in preparing the facility for the summer or winter configuration, which led to corrective action requests. In recent summers, at ASN’s request, EDF ran operating tests on the emergency diesel generator sets during a period of high temperatures. The purpose of these tests is to confirm the demonstration of the qualification of this equipment. The OEF carried out by EDF following the heatwaves of the summer of 2022 identified no need to modify the measures already in place. 2.5 CONFORMITY AND MAINTENANCE OF THE INSTALLATIONS 2.5.1 Maintenance of the installations and management of subcontracted activities Maintenance of the installations Preventive maintenance is an essential line of defence in ensuring the conformity of a facility with its baseline safety requirements. In order to improve the reliability of the safety-important equipment but also the industrial performance, EDF is optimising its maintenance activities, drawing on practices used in conventional industry and by the licensees of NPPs in other countries. In 2008, EDF decided to deploy the maintenance methodology called “AP913”, developed by the American nuclear licensees and built around two main points: organisational changes to enhance monitoring of the reliability of the equipment and systems and implementation of a new type of preventive maintenance programmes. The AP913 implementation diagnostic performed by EDF in mid-2016 revealed difficulties with implementing performance monitoring and with the increase in the maintenance tasks generated by the AP913 maintenance programmes. In 2017, EDF thus defined strategic guidelines for maintenance and reliability. It specified the roles of the various departments and professions related to the performance of maintenance, by reaffirming that the maintenance departments are responsible for the project ownership of the equipment they maintain, in particular in a context of continued operation of the reactors beyond 40 years. EDF also adopted function reviews to obtain an integrated view of the equipment and systems participating in each function, as well as implementing a new phase of its project to control the volume of maintenance. Management of subcontracted activities Reactor maintenance operations are to a large extent subcontracted by EDF to outside contractors. EDF justifies the use of subcontracting by the need to call on specific or rare expertise, as well as the highly seasonal nature of reactor outages and thus the need to absorb workload peaks. EDF’s decision to resort to subcontracting must not compromise the technical skills it must retain in-house in order to exercise its responsibility as licensee with regard to the protection of people and the environment and to be able to effectively monitor the quality of the work performed by the subcontractors. Poorly managed subcontracting is liable to lead to poor quality work and have a negative impact on the safety of the facility and the radiation protection of the workers involved. EDF takes the necessary steps to control the risks associated with the subcontracted activities and regularly updates them. EDF has thus reinforced the preparation of reactor outages, more particularly to guarantee the availability of human and material resources. In 2023, ASN carried out 53 inspections of the procurement chain for safetyimportant equipment intended for NPPs. They evaluated the control of manufacturing by these suppliers, along with the surveillance carried out by EDF. Of these inspections, 38 were related to the manufacture of NPE and the procurement of large forged components intended for the first EPR 2 reactors and the EDF reactors in operation. These inspections took place in France, Spain, Italy and Japan, primarily in the manufacturing plants. ASN was thus able to check the quality of manufacturing and verify how responsibilities were assumed by NPE manufacturers, organisations approved for evaluating NPE conformity and EDF in terms of its surveillance of NPE procurement. These inspections identified a number of good practices in the performance of the activities entrusted to the suppliers. However, they also revealed a lack of familiarity with certain regulatory requirements within the subcontracting chain, a lack of expertise in certain special processes, and a need for improvement to the quality of EDF’s surveillance of its suppliers. During these inspections, ASN was able to evaluate the steps taken to mitigate the risk of falsification and counterfeiting during equipment manufacturing. ASN finds that the identified number of cases of irregularity is on the rise. These findings were shared with EDF, so that improvements can be made. In 2024, ASN will continue with its international commitments regarding supplier oversight, within the Committee on Nuclear Regulatory Activities (CNRA) of the Nuclear Energy Agency (NEA). This commitment entails active participation in the Working Group on Supply Chain (WGSUP) involving the nuclear safety regulators. Within this working group, ASN shares the conclusions of its inspections with its counterparts and takes part in joint inspections, such as the international inspection overseen by the British Office for Nuclear Regulation (ONR) in 2023 at a nuclear equipment supplier in Japan. OVERSIGHT OF SUPPLIERS OF EQUIPMENT IMPORTANT FOR NUCLEAR SAFETY ASN Report on the state of nuclear safety and radiation protection in France in 2023 305 • 10 • The EDF Nuclear Power Plants 10 05 15 08 11 04 14 06 07 13 AP 03 02 09 12 01
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