Abstracts ASN Report 2021

CHINON SITE Situated in the municipality of Avoine in the Indre‑et‑Loire département, on the left bank of the river Loire, the Chinon site accommodates various nuclear installations, some in operation, others shut down or undergoing decommissioning. On the south side of the site, the Chinon B NPP comprises four in-service 900 MWe reactors; the first two –constituting BNI 107– were commissioned in 1982-1983, while the second two –constituting BNI 132– were commissioned in 1986‑1987. To the north, the three old graphite-moderated GCRs designated Chinon A1, A2 and A3, are currently being decommissioned. The site also accommodates the Irradiated Materials Facility (AMI), designed for the expert assessment of activated or contaminated materials, whose assessment activities have now ceased and been entirely transferred to a new laboratory called “the Lidec”, and to the Inter-Regional Fresh Fuel Warehouse (MIR). Chinon nuclear power plant Reactors B1, B2, B3 and B4 in operation ASN considers that the performance of the Chinon NPP is in line with its general assessment of the EDF plants in the areas of nuclear safety and radiation protection. The environmental performance, which was below average at the beginning of 2021, improved significantly in the course of the year. Although progress was observed in 2021, particularly in terms of safety, the results in the areas of the environment and radiation protection must be consolidated. With regard to safety, ASN considers that the incident and accident management situation is once again satisfactory, even if it noted diff iculties in the management of the On-Site Emergency Plan (PUI) documentation. Alongside this, although ASN observes a drop in the number of significant events resulting from noncompliance with the reactor General Operating Rules (RGE) by the operational management teams, the analysis of deviations that can affect safety can be further improved. ASN considers that the radiation protection performance of the Chinon NPP remains relatively satisfactory. The ASN inspections conducted in 2021 showed that progress had been made, which was expected further to the 2020 assessment, but also that organisational improvements were still required. In view of the site’s good performance in this area before 2020, ASN considers that it must be a priority for the site in 2022. The environmental protection performance of the Chinon NPP must be improved. The gaseous and liquid effluent discharges are well below the national average. ASN nevertheless considers that management of the hydrocarbons leaving the oil f ilters is a point requiring particular attention in 2022. In addition, waste management is poorly compliant with best practices and must be improved in 2022. In 2021, labour inspection revealed the site’s weaknesses in the prevention of risks of falling f rom height, in the legibility of some asbestos identif ication/location f iles, or even the exhaustiveness of the checks carried out, due to the organisational set-ups between various EDF entities. Inspection of the electrical risk continued in 2021 (and will remain a priority in 2022); it revealed several shortcomings, particularly concerning the knowledge of the premises and installations to inspect, the initial regulatory verif ications and the correction of the identified deviations. Lastly, several accidental exposures of employees to asbestos led ASN to challenge EDF on the quality and legibility of the asbestos identification/location files, by asking the licensee to work on the subject in 2022. Reactors A1, A2 and A3 undergoing decommissioning The graphite-moderated GCR series comprises six reactors, including Chinon A1, A2 and A3. These first-generation reactors used natural uranium as the fuel, graphite as the moderator and were cooled by gas. This plant series includes “integrated” reactors, whose heat exchangers are situated under the reactor core inside the vessel, and “non-integrated” reactors, whose heat exchangers are situated on either side of the reactor vessel. The Chinon A1, A2 and A3 reactors are “non-integrated” GCRs. They were shut down in 1973, 1985 and 1990 respectively. Reactors A1 and A2 were partially decommissioned and transformed into storage facilities for their own equipment (Chinon A1 D and Chinon A2 D). These operations were authorised by the Decrees of 11 October 1982 and 7 February 1991 respectively. Chinon A1 D is partially decommissioned at present and has been set up as a museum –the Museum of the Atom– since 1986. Chinon A2 D is also partially decommissioned and houses the GIE Intra (which operates robotised machines for interventions on accident-stricken nuclear installations). Complete decommissioning of the Chinon A3 reactor was authorised by the Decree of 18 May 2010, with a decommissioning “under water” scenario. In March 2016, EDF announced a complete change of decommissioning strategy for its definitively shut down reactors. In this new strategy, the planned decommissioning scenario for all the reactor pressure vessels is decommissioning “in air” and the Chinon A2 reactor pressure vessel would be decommissioned first (see chapter 13 of the full ASN Report). In this context, ASN has analysed the periodic safety review concluding reports submitted by EDF for the six GCRs, supplemented further to the requests fromASN. On completion of its analysis, ASN indicated in December 2021 that it has no objection to the continued operation of BNI 133 (Chinon A1 reactor), BNI 153 (Chinon A2 reactor) and BNI 161 (Chinon A3 reactor). It will verify during the examination of the decommissioning files for these reactors, which are to be submitted by EDF in late 2022, that the decommissioning operations are carried out under suitable conditions of safety and radiation protection, within controlled time frames. For the Chinon A2 reactor, EDF has continued the decommissioning preparation operations situated outside the reactor pressure vessel, particularly as concerns removal of the shells from the heat exchanger premises, and continued the investigations inside the pressure vessel. EDF has also 54 ABSTRACTS – ASN Report on the state of nuclear safety and radiation protection in France in 2021 REGIONAL OVERVIEWOF NUCLEAR SAFETY AND RADIATION PROTECTION