Fire risks ASN finds no significant change with regard to control of fire risks within the NPPs. The overall performance level is below that expected. Although progress can be seen on some sites, performance is deteriorating on others. The number of fire outbreaks in 2024 is very slightly up on 2023. Three of these fire outbreaks led to triggering of the PUI on the site concerned, including two for transformer fires, which were the year’s most significant fires. ASN has observed certain improvements in the management of the fire risk in the NPPs, notably in management of detection and in personnel training. However, ASN considers that on all the NPPs, EDF must improve management of the temporary storage of combustible materials during construction work and maintenance operations. ASN also noted the need on certain sites to improve the oversight of sectorisation and how anomalies on this subject are dealt with. ASN found that EDF is continuing with its measures to improve management of the fire risks in the premises identified as being particularly susceptible to this hazard in the light of the potential consequences for safety. Finally, EDF is working on deploying a new firefighting organisation on its sites, so that it can more effectively tackle fires and prevent them from spreading. Changes are thus planned with regard to personnel individual protection equipment, training and organisation with the Departmental Fire and Emergency Services (SDIS). EDF’s goal is to complete the deployment of these changes in 2024. On several sites, this will lead to improvements to the response capacity jointly with the SDIS. Explosion risks ASN checks the prevention and monitoring measures taken by EDF with regard to the risk of explosion. As part of its labour inspectorate duties, ASN also ensures compliance with the “EXplosive ATmospheres” (ATEX) regulations to ensure worker protection. ASN considers that the level of explosion- related risk management is not yet up to the required standard for all the NPPs. The maintenance and inspection doctrine and, on certain sites, compliance with prevention measures, is not always applied satisfactorily, notably with regard to the risks related to the presence of hydrogen in the installations. ASN however notes the efforts made by EDF to reduce the deviations observed. ASN considers that EDF must continue to pay particular attention to this subject and ensure that it is dealt with using all necessary rigour on all the sites. Internal flooding risks In 2019, ASN asked EDF to supplement its approach for controlling the internal flooding risk, notably to ensure correct operation of the floor drains, reinforce maintenance of the lines liable to lead to internal flooding and ensure improved management of their ageing. In response to these requests, EDF implemented improvement measures. In addition, EDF is continuing its field visits to identify the piping which could cause internal flooding in the electrical buildings, which are particularly vulnerable to this risk, in order to assess the need to reinforce its maintenance. In accordance with ASN’s requests, EDF will extend these surveys to the other buildings. ASN sees as positive the fact that EDF has initiated the refurbishment of the circuits of certain cooling systems that are particularly susceptible to corrosion. Seismic risks The inspection programmes implemented by EDF lead it to regularly notify ESS owing to the lack of seismic resistance of certain equipment. These events are the result of targeted inspections gradually being deployed by EDF. These non- compliances can have serious consequences in the event of an earthquake and they are thus systematically analysed. On 11 November 2019, an earthquake occurred in the municipality of Le Teil. It led EDF to shut down the reactors of the Cruas-Meysse NPP so that it could conduct checks, which revealed no anomaly. In November 2019, ASN asked EDF to determine whether this earthquake should lead to a revision of the seismic levels to be adopted for protection of the Tricastin and Cruas-Meysse NPP sites. After investigations in the field, EDF defined a new hazard level to be used in the seismic reassessment studies associated with the fourth periodic safety review of the Cruas-Meysse site. ASN also asked EDF to continue with its investigations in order to obtain an improved characterisation of the existing faults round the Tricastin and Cruas-Meysse NPPs. EDF undertook a wide-ranging programme of field investigations which continued in 2024 and the conclusions of which are to be taken into account during the fifth periodic safety review of the reactors on the sites concerned. 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 or that the operational implementation of the recommendations of the particular control rules could be improved. 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, which continued in 2024, is to confirm the demonstration of the qualification of this equipment for heatwave conditions. 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 ASN Report on the state of nuclear safety and radiation protection in France in 2024 311 01 The EDF Nuclear Power Plants 10 02 03 04 05 06 07 08 09 11 12 13 14 15 AP
RkJQdWJsaXNoZXIy NjQ0NzU=