ASN Report 2022

SAINT‑LAURENT‑DES‑EAUX SITE The Saint-Laurent-des-Eaux site, situated on the banks of the river Loire in the municipality of Saint‑Laurent‑Nouan in the Loir‑et‑Cher département, comprises various nuclear installations, some of them in operation and others undergoing decommissioning. The Saint‑Laurent‑des‑Eaux NPP comprises two operating reactors, B1 and B2, which were commissioned in 1980 and 1981 and constitute BNI 100. The site also features two old GCRs, A1 and A2, currently in the decommissioning phase, and two silos for storing the graphite sleeves from the operation of reactors A1 and A2. Saint-Laurent-des-Eaux nuclear power plant Reactors B1 and B2 in operation ASN considers that the environmental protection performance of the Saint Laurent-des-Eaux NPP stands out positively with respect to its general assessment of EDF plant performance, and that safety and radiation protection performance is in line with the general assessment on these themes. ASN considers that the site’s nuclear safety performance improved in 2022. The changes in the safety management plan have restored a satisfactory level of performance. The in-depth inspection conducted by ASN in June 2022 confirmed this improvement. These factors must nevertheless be considered alongside the fact that only one refuelling outage was carried out in 2022 instead of the usual two. There remains room for progress in supervision rigour (monitoring in the control room, operating range excursion), configuring of the systems and application of reliability-enhancement practices. This recovery will have to be confirmed in 2023 with the performance of two refuelling outages, including the fourth ten‑yearly outage of reactor 2. Maintenance at the Saint-Laurent-des-Eaux NPP improved in 2022 compared with 2021, and reached a level considered to be relatively satisfactory. Few significant events are caused by maintenance deficiencies. Here again these elements must be considered alongside the fact that there was only one refuelling outage in 2022. It is to be noted that a significant event was again reported in 2022 further to errors during inspections of the anti-chatter devices which limit the movements of the primary cooling system in the event of high stresses, such an earthquake situation, which shows that the subject is still not fully mastered. Generally speaking, the management of radiation protection at the Saint‑Laurent‑des‑Eaux NPP meets ASN expectations. The site’s performance is considered stable with respect to 2021. The setting up of the radiation protection skills centre in 2022 is found to be satisfactory on the whole. The site’s organisation to meet the regulatory environmental requirements is considered highly effective, particularly in view of the quantities of effluents discharged. The use of retention areas to store equipment must be monitored and the control of the sheets framing the discharge conditions must be consolidated. As far as labour inspection was concerned, ASN focused its attention on monitoring the accidents and “near-accidents” in the Centre-Val de Loire region. In this context, and with no serious accidents necessitating specific investigations on the Saint-Laurent-des-Eaux site, only cross-functional subjects underwent checks (post Fukushima, radiation protection skills centre, reactive inspection). As in 2021, these checks were conducted jointly by the labour inspectorate and safety inspection. In 2023, following on from the actions carried out in 2021 and 2022, the electrical risks shall remain a priority for the ASN labour inspectorate. Reactors A1 and A2 undergoing decommissioning The former Saint‑Laurent‑des‑Eaux NPP constitutes a BNI comprising two “integrated” GCR reactors, reactors A1 and A2. These first-generation reactors used natural uranium as the fuel, graphite as the moderator and were cooled by gas. Their final shutdown was declared in 1990 and 1992 respectively. Complete decommissioning of the installation was authorised by the Decree of 18 May 2010. On completion of the analysis of the periodic safety review concluding reports for all the GCR reactors, ASN indicated in December 2021 that it has no objection to the continued operation of BNI 46 (Saint‑Laurent reactors A1 and A2). It will verify during the examination of the new decommissioning files for these reactors, which were submitted by EDF in late 2022 to set out the new “in air” decommissioning strategy, that the decommissioning operations are carried out under suitable conditions of safety and radiation protection, within controlled time frames. In 2022, EDF continued its decommissioning work sites, and more specifically the decommissioning work outside the reactor vessel (Saint-Laurent A2) and the decontamination of the pool (Saint-Laurent A1). ASN considers that the level of safety of the Saint‑Laurent‑des‑Eaux A reactors is satisfactory. ASN’s inspections found that the overall upkeep of the premises and worksites was good. In addition, the organisation put in place to meet the commitments made further to the inspections and significant events is satisfactory. The same goes for the monitoring of outside contractors and the setting up of the radiation protection skills centres. Even though the in-service monitoring of the pressure equipment is performed correctly, improvements are expected, notably to ensure that the particularities of certain equipment items are properly taken into account. ABSTRACTS – ASN Report on the state of nuclear safety and radiation protection in France in 2022 53 Regional overview of nuclear safety and radiation protection • CENTRE-VAL DE LOIRE •