ASN Report 2022

Auvergne‑Rhône‑Alpes REGION The Lyon division regulates nuclear safety, radiation protection and the transport of radioactive substances in the 12 départements of the Auvergne-Rhône-Alpes region. In 2022, ASN carried out 330 inspections in the Auvergne‑Rhône‑Alpes region, comprising 116 in the Bugey, Saint‑Alban, Cruas‑Meysse and Tricastin Nuclear Power Plants (NPPs), 91 in plants and installations undergoing decommissioning, 107 in small‑scale nuclear activities and 16 in the radioactive substance transport sector. ASN also carried out 19 days of labour inspections in the four NPPs and on the Creys‑Malville site. In 2022, ASN was notified of 36 significant events rated level 1 on the International Nuclear and Radiological Event Scale (INES scale), of which 30 occurred in Basic Nuclear Installations (BNIs) and 6 in small-scale nuclear activities. Furthermore, one event was rated level 2 on the ASN‑SFRO scale (scale specific to radiation protection events affecting patients undergoing radiotherapy procedures). In the context of their oversight duties, the ASN inspectors issued one violation report. ASN also served formal notice on one nuclear licensee and one head of a nuclear activity to comply with the regulations. ASN temporarily modified the requirements regulating thermal discharges from the Bugey, Saint-Alban and Tricastin NPPs during the heat waves of summer 2022 (see “Notable events” in the introduction to this report). BUGEY SITE The Bugey industrial site comprises various facilities, including the Bugey NPP operated by EDF on the municipality of Saint-Vulbas in the Ain département, 35 km east of Lyon. It comprises four Pressurised Water Reactors (PWRs), each of 900 Megawatts electric (MWe), commissioned in 1978 and 1979. Reactors 2 and 3 constitute BNI 78 and reactors 4 and 5 constitute BNI 89. The site also accommodates Bugey 1, a graphite-moderated Gas-Cooled Reactor (GCR) commissioned in 1972, shut down in 1994 and currently undergoing decommissioning, the Activated waste packaging and interim storage facility (Iceda) and the Inter-Regional Warehouse (MIR) for fuel storage. Lastly, the site accommodates one of the regional bases of the FARN, the special Nuclear Rapid Intervention Force created by EDF in 2011 further to the Fukushima Daiichi NPP accident in Japan. Its role is to intervene in pre-accident or accident situations, on any NPP in France, by providing additional human resources and emergency equipment. Bugey nuclear power plant Reactors 2, 3, 4 and 5 in operation ASN considers that the overall performance of the Bugey NPP with regard to nuclear safety is below ASN’s general assessment of EDF plant performance. However, it considers that the overall performance of the Bugey NPP with regard to radiation protection and environmental protection is in line with ASN’s general assessment of EDF plant performance. With regard to nuclear safety, ASN considers that the NPP’s performance has deteriorated in 2022, despite an industrial context with lower workloads than in the preceding years. ASN still observes vulnerabilities in the configuring of the systems, the management of the periodic tests, the scheduling and performance of the maintenance activities and requalification tests, and the problems of spare parts. Despite some initial improvements, progress must be made in emergency situation management and the control of fire risks. Progress must also be made in keeping the first barrier, that is to say the fuel containment cladding, in good condition. The management of the modifications associated with the fourth ten‑yearly outages now seems to be satisfactory on the whole. Nevertheless, following the detection in 2022 of deterioration of a seal of the system for maintaining dryness, installed between the pool and the vessel mating surface on reactors 2 and 4 during their fourth ten‑yearly outages, ASN served EDF formal notice on 3 August 2022 to comply with the applicable provisions of the safety analysis report of reactors 2, 4 and 5 at the 38 ABSTRACTS – ASN Report on the state of nuclear safety and radiation protection in France in 2022