ASN Report 2023

EDF will begin the first ten yearly outage associated with this review at the end of 2025. ASN will issue a position statement on the generic phase of this periodic safety review six months in advance. The 1,450 MWe reactors The second periodic safety review In 2011, EDF transmitted the envisaged guidelines for the generic study programme for the second periodic safety review of the 1,450 MWe reactors, notably concerning the prevention of core melt and mitigation of the consequences of severe accidents. ASN issued a position statement in February 2015 regarding the guidelines for this second periodic safety review. It in particular asked EDF to look for measures to mitigate the radiological consequences of design-basis accidents and measures with a strong impact in terms of preventing and mitigating the consequences of severe accidents. ASN issued a position statement in 2022 on this generic phase. It underlined the significant safety improvements made to the reactors on the occasion of this periodic safety review. The four 1,450 MWe reactors submitted their review concluding reports between 2020 and 2023. The third periodic safety review After consulting the public and obtaining the opinion of the GPR regarding the guidelines proposed by EDF for its study programme of the generic phase of the third periodic safety review of the 1,450 MWe reactors, ASN issued a position statement in July 2023. The periodic safety review will allow definition of the conditions for continued operation of these reactors for up to 40 years. ASN considered that the general objectives set by EDF for this review were acceptable in principle. These objectives are consistent with those set for the fourth periodic safety reviews of the 900 MWe and 1,300 MWe reactors. However, ASN asked EDF to add to or clarify some of these general objectives, in the same way as it had done for the 900 MWe and 1,300 MWe reactors. The safety reassessment of these reactors and the resulting improvements will be carried out in the light of the safety objectives of the new-generation reactors, such as the EPR, the design of which meets significantly reinforced safety requirements. In addition, the modifications associated with this periodic safety review will incorporate those linked to deployment of the “hardened safety core”. ASN reinforced the involvement of the public in the various steps of the fourth periodic safety review of the 900 MWe reactors. It is currently doing the same for the generic phase of the fourth periodic safety review of the 1,300 MWe reactors. After consulting the public in 2019 on the guidelines for this review, ASN – together with the National Association of Local Information Committees and Commissions (Anccli) – in 2023 organised technical dialogue days for the main issues covered by the review. Four meetings thus offered an opportunity for discussions with representatives from the Local Information Committees (CLIs) and environmental associations on accidents with and without core melt, the hazards faced by the reactors, equipment ageing, environmental protection, pressure vessel strength and OHF. In 2023, ASN also took part in preparing the national consultation to be held under the aegis of the High Committee for Transparency and Information on Nuclear Security (HCTISN) in the first half of 2024. This consultation will cover the provisions proposed by EDF for the generic phase of the periodic safety review. It will notably rely on a website, public meetings and webinars. ASN will take account of its conclusions in preparing its position on the generic phase of this periodic safety review scheduled for 2025. INVOLVEMENT OF THE PUBLIC IN THE 4th PERIODIC SAFETY REVIEW OF THE 1,300 MWe REACTORS As in any industrial installation, the equipment in NPPs experiences ageing. This ageing is the result of physical phenomena (corrosion of metals, hardening of polymers, hardening of certain steels under the effect of irradiation or temperature, swelling of certain concretes, etc.) which can degrade their characteristics according to their age or their operating conditions. This degradation obliges the licensee to repair or replace the equipment or to limit the lifetime of non-replaceable equipment, such as the reactor pressure vessel (see point 2.2.4). The ageing management process implemented by EDF is based on three main points: anticipating the effects of ageing as of the design stage, monitoring the actual condition of the facility and repairing or replacing equipment degraded by the effects of ageing. Before being installed, safety-important equipment more particularly undergoes a qualification process to ensure its ability to perform its functions in conditions corresponding to the situations in which it will be needed, accident situations in particular. The management of equipment ageing, and of the risk of obsolescence – which refers to difficulties linked to guaranteeing the procurement of spares over time – are essential to maintaining a satisfactory level of safety. They also contribute to reactor conformity with the applicable rules being maintained over time. The control of ageing is given particular attention by ASN during the fourth periodic safety reviews. The provisions adopted or planned by EDF are examined and inspected, to ensure that the risks associated with ageing and obsolescence are controlled satisfactorily. THE AGEING OF NUCLEAR POWER PLANT EQUIPMENT 316 ASN Report on the state of nuclear safety and radiation protection in France in 2023 • 10 • The EDF Nuclear Power Plants

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