ASN Report 2022

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 also continued the decommissioning of the Chinon A3 heat exchangers. After completing the decommissioning work in the heat exchangers “South” building and transferring all the cylinders to the Industrial centre for grouping, storage and disposal (Cires), the decommissioning work on the “North” heat exchangers building has started, with the transfer of the first cylinders in June 2022. ASN considers that the level of safety of the Chinon nuclear installations undergoing decommissioning (Chinon A1, A2 and A3) is satisfactory. The inspections conducted in 2022 revealed in particular the use of high-performance computing aids for the management of the work sites and the documents. In this respect, one must nevertheless note the reporting of two significant events associated with a lack of equipment and document modification tracking which occurred in 2017 and 1993. The procedures currently implemented contain provisions to avoid the recurrence of such deviations. Improvements are expected in the tracking of the periodic inspections of the NPP equipment items which are under the responsibility of the Chinon dismantling organisation. NUCLEAR “FUEL CYCLE” FACILITIES Inter-regional fresh fuel warehouse Commissioned in 1978, the Chinon MIR is a facility for storing fresh fuel assemblies pending their utilisation in various EDF reactors. It constitutes BNI 99. Along with the Bugey MIR, it contributes to the management of flows of fuel assembly supplies for the reactors. The facility has been operating nominally since the reception and storage of fresh fuel assemblies resumed in 2020, in a configuration in which the facility was equipped with a new handling crane in 2019 and under an updated baseline authorised by ASN. During its inspection in 2022, ASN observed a generally satisfactory level of safety, and more specifically good upkeep of the premises and the availability of the fuel assembly reception and shipping files. 1. Inerting is a procedure that consists in replacing a reactive atmosphere (oxidising, inflammable, explosive) by an inert gas such as nitrogen, CO2 or argon. RESEARCH FACILITIES UNDERGOING DECOMMISSIONING Irradiated materials facility The AMI, which was declared and commissioned in 1964, is situated on the Chinon nuclear site and operated by EDF. This facility (BNI 94) has stopped operating and is being decommissioned. It was primarily intended for performing examinations and expert assessments on activated or contaminated materials from the PWR reactors. The expert assessment activities were completely transferred in 2015 to a new facility on the site, the Integrated Laboratory (Lidec) of the Construction and Operation Expert Appraisal and Inspection Centre (Ceidre). Decree 2020-499 for AMI decommissioning was published on 30 April 2020 and the new RGEs were approved by ASN in April 2021, thereby enabling the decree to enter into application. ASN also subjected the starting of several future decommissioning operations to its approval. Further to the updating of the resolution regulating the installation’s discharge limits in July 2022, a new discharge monitoring system has been put into service and decommissioning operations have started that include equipment cutting-up and interventions in several facilities. The legacy magnesian waste from the expert assessments of certain parts and necessitating inerting operations(1) to meet the disposal criteria of the French radioactive waste management agency (Andra) has been packaged and re‑characterised in 2021. The characterisation results were not as expected, making it necessary to apply to Andra for a waiver to allow acceptance of the waste. The waste removal work was therefore stopped pending the outcome of this procedure. The work is expected to resume by the end of 2023. Lastly, in early February 2021, EDF filed a decommissioning authorisation application for the highly active liquid effluent circuits, which is currently being examined. Given that EDF reported technical and contractual difficulties as of April 2022, these operations – which were initially planned as of 2023 – will have to be rescheduled. On the basis of the checks made during these inspections, ASN considers that the safety management applied at the AMI is satisfactory, particularly with regard to the application of the new RGEs approved further to the decommissioning transition. The outside contractor monitoring methods implemented are satisfactory on the whole, and vigilance is expected in the continuation of the operations initiated to deal with the legacy chemical products. 52 ABSTRACTS – ASN Report on the state of nuclear safety and radiation protection in France in 2022 Regional overview of nuclear safety and radiation protection • CENTRE-VAL DE LOIRE •