ASN Report 2022

Marking events of the year 2022 Fission product evaporators‑concentrators Six evaporators are used in facilities R2 and T2 to concentrate the fission product solutions before they undergo vitrification treatment. After measuring the thickness of the walls of these evaporators during the periodic safety reviews of the facilities as from 2012, a more advanced state of corrosion than predicted at the design stage was discovered. ASN therefore decided to regulate the continued operation of these evaporators in order to tighten their surveillance and to have additional means installed to mitigate the consequences in the event of a leak or rupture. In the course of this special surveillance, thickness measurements taken in September 2021 on evaporator 4120.23 of the T2 facility had shown that the operational criterion for shutting down the evaporator had been reached, which led Orano to decide not to restart the evaporator. To replace these evaporators, Orano is building new facilities baptised “New Fission Product Concentrations” (NCPF) and comprising six new evaporators. This particularly complex project has necessitated several authorisations. It was the subject of two ASN resolutions in 2021, concerning the active connection of the process of the three evaporators of NCPF T2 on the one hand and the three evaporators of NCPF R2 on the other. With regard to the NCPF T2 project, the T2 facility has been shut down since September 2022 in order to connect the new evaporators to the existing facilities and to continue the tests prior to commissioning, which is planned for April 2023. ASN has performed two inspections concerning the tests conducted by the licensee in 2022 and will continue its specific oversight operations in 2023. The NCPF R2 project is offset by about one year with respect to NCPF T2, meaning that the first tests were started at the end of 2022. The operations to connect the new evaporators to the existing facilities are planned as of autumn 2023, with commissioning scheduled for the first half of 2024. Storage of plutonium-bearing materials Since the end of 2021, the Orano La Hague site been faced with a problem of saturation of the storage capacities for these materials, linked to the operating difficulties encountered by the Melox plant. This problem gave rise to a hearing of Orano by the ASN Commission on 28 September 2021 and was also examined during the joint hearing of Orano and EDF relative to the balance of the “nuclear fuel cycle” on 10 February 2022. To cope with this storage capacity problem, Orano has submitted several noteworthy modification authorisation applications with the aim of increasing its plutoniumbearing material storage capacities: ཛྷa first application was filed in September 2021 to increase the storage capacities for plutonium-bearing materials in the BST1 facility. This led to an ASN authorisation in April 2022; ཛྷa second application was filed in September 2022 to increase the storage capacities for plutonium-bearing materials in the R4 facility. This file is currently being examined by ASN with the technical assistance of IRSN. Orano plans filing further applications of the same nature if the storage capacity problems persist. Revision of the resolutions regulating the site’s discharges On 16 June 2022, ASN adopted two resolutions regulating the conditions of water intake, consumption, discharge into the environment, and the effluent discharge limits for the La Hague site. As of 1 January 2023, these resolutions update the resolutions of 2015 which were applicable until now. In accordance with the regulations, the resolution modifying the limits applicable to effluent discharges from the installation was approved by Ministerial Order published in the Official Journal of 7 December 2022. The resolutions adopted by ASN take into account some of the licensee’s requests concerning more specifically the modification of the maximum monthly activity concentration of rare gases, including krypton-85, measured at the regulatory environmental monitoring stations, and regulation of the limits and conditions of monitoring discharges into the sea of eleven chemical substances detected by the licensee in small quantities in the discharges during a regulatory compliance evaluation procedure. Other requests from the licensee, representing lower risks, have also been accepted if justified in view of the environmental risks and compatible with the applicable regulatory provisions, for example concerning the management of drainage waters from certain facilities, the conditions of effluent analyses and the frequency of submitting the regulatory studies determining the possibilities of reducing radiological and chemical discharges. Lastly, some requests asking for a relaxation of the requirements concerning water intakes, monitoring of the marine environment or the effluent discharge conditions, were rejected. These resolutions ratify the principle of a significant reduction in the discharges into the sea authorised for certain radiological or chemical substances, in view of experience feedback and the improvement in effluent management practices and techniques. They also impose complementary provisions for environmental monitoring, evaluation of the radiological impact on the populations and effluent monitoring. ABSTRACTS – ASN Report on the state of nuclear safety and radiation protection in France in 2022 77 Regional overview of nuclear safety and radiation protection • NORMANDIE •