Abstracts ASN Report 2021

The gaseous effluents are released mainly when the fuel assemblies are sheared and during the dissolution process. These gaseous effluents are treated by washing in a gas treatment unit. The residual radioactive gases, particularly krypton and tritium, are checked before being discharged into the atmosphere. The liquid effluents are treated and usually recycled. Some radionuclides, such as iodine and tritium, are channelled –after being checked– to the sea discharge outfall. This outfall, like the other outfalls of the site, is subject to discharge limits. The other effluents are routed to the site’s packaging units (solid glass or bitumen matrix). FINAL SHUTDOWN AND DECOMMISSIONING OPERATIONS ON CERTAIN FACILITIES The former spent fuel reprocessing plant UP2‑400 (BNI 33) was commissioned in 1966 and has been def initively shut down since 1 January 2004. Final shutdown also concerns three BNIs associated with the UP2-400 plant: BNI 38 (which comprises the effluents and solid waste treatment station No. 2 –STE2, and the oxide nuclear fuel reprocessing facility No. 1 –AT1), BNI 47 (radioactive source fabrication unit –ELAN IIB) and BNI 80 (HAO facility). Orano submitted two partial decommissioning authorisation requests for BNIs 33 and 38 in April 2018. The schedule pushbacks requested by the licensee lead to decommissioning completion deadlines in 2046 and 2043 instead of 2035, the current deadline prescribed for the two BNIs. Further to Orano’s additions to the file concerning firstly the elimination of the interactions between the MAPu facility and the plutonium BST1 facility in the event of an earthquake, and secondly the memorandum in response to the opinion of the environmental authority, a public inquiry was held from 20 October to 20 November 2020. At the end of the inquiry, the inquiry commission issued a favourable opinion. In 2021, ASN continued the examination of these f iles and remains particularly vigilant about the justif ication for the various decommissioning stages and the reassessment of the safety of the facilities that are maintained in their current condition. ASN notes that the schedule push-backs requested are signif icant and largely due to the delays in legacy waste retrieval and packaging. Consequently, ASN will continue to monitor the management of these projects in 2022. Marking events of the year 2021 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 context of this special surveillance, thickness measurements taken in September 2021 on evaporator 4120.23 of the T2 facility showed that the operational criterion for shutting down the evaporator had been reached. In view of this, Orano decided not to restart this evaporator. To replace these evaporators, Orano has built new facilities baptised “New Fission Product Concentrations” (NCPF) and comprising six new evaporators. This project, which is particularly complex, has required several authorisations and was addressed by 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. Storage of plutonium-bearing materials Orano filed a noteworthy modification authorisation application in September 2021 aiming to increase the plutonium-bearing materials storage capacities in the BST1 facility. This application is part of the more general procedure conducted by Orano in response to the saturation of the storage capacities for these materials, which is linked to the operating difficulties experienced by the Melox plant. This problem gave rise to a specific 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. Noncompliance with the halon substitution deadlines for certain fire-fighting devices At the end of 2020, Orano informed ASN that the deadline of 31 December 2020 set by the European regulation governing the use of ozone-layer depleting substances could not be met for the disconnection of the halon fire-extinguishing system of facility AD2 due to contractual and technical difficulties in finding an alternative solution using another extinguishing agent. ASN conducted an inspection on 27 January 2021 to examine the industrial options chosen by the licensee to ensure compliance with the regulations and the project management steps since the regulation was published. The inspection confirmed that the fire-protection equipment using halon 1301 was still in service in the AD2 facility. It also revealed shortcomings in the leak detection methods used on these systems. In view of these factors, ASN decided to regulate the time frames for modifying the fire-extinguishing system of the AD2 facility, by issuing a compliance notice dated 22 April 2021. 78 ABSTRACTS – ASN Report on the state of nuclear safety and radiation protection in France in 2021 REGIONAL OVERVIEWOF NUCLEAR SAFETY AND RADIATION PROTECTION