LES ACTIVITÉS NUCLÉAIRES : RAYONNEMENTS IONISANTS ET RISQUES POUR LA SANTÉ ET L’ENVIRONNEMENT The fuel assemblies are then sheared and dissolved in nitric acid to separate the pieces of metal cladding from the spent nuclear fuel. The pieces of cladding, the retaining grids and the fuel assembly end-pieces, which are insoluble in nitric acid, are transferred to a compacting and conditioning unit. The nitric acid solution comprising the dissolved radioactive substances is then processed in order to extract the uranium and plutonium and leave the fission products and other transuranic elements. After purification, the uranium is concentrated and stored in the form of a uranyl nitrate solution. It is intended for conversion in the TU5 facility on the Tricastin site into a solid compound (U3O8), called “reprocessed uranium”. After purification and concentration, the plutonium is transformed back into plutonium oxide, packaged in sealed containers and stored. It is then intended for the fabrication of MOX fuels in the Orano plant in Marcoule (Melox). The effluents and waste produced by the operation of the plants The fission products and other transuranic elements resulting from reprocessing are concentrated, vitrified and packaged in standard vitrified waste packages (CSD-V). The pieces of metal cladding are compacted and packaged in standard compacted waste packages (CSD-C). These reprocessing operations also use chemical and mechanical processes, the operation of which generates gaseous and liquid effluents as well as solid waste. 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. After verification and in accordance with the discharge limits, certain radionuclides, such as iodine and tritium, are sent to the marine outfall. The other effluents are routed to on-site conditioning units (solid glass or bitumen matrix). The solid waste is conditioned on-site, either by compacting, or by encapsulation in cement, or by vitrification. The solid radioactive waste from the reprocessing of spent fuel assemblies from French reactors is, depending on its composition, either sent to the low-level and intermediate-level, short-lived waste (LLW/ILW-SL) repository at Soulaines-Dhuis (see chapter 13) or stored on the Orano site at La Hague, pending a final disposal solution; this is notably the case for the CSD-V and CSD-C, for which final disposal is envisaged in the planned Cigéo project (see chapter 13). In accordance with Article L. 542-2 of the Environment Code, the radioactive waste from the reprocessing of spent fuel assemblies from abroad, is sent back to the producer country. It is however impossible to physically separate the waste according to the fuel from which it originates. In order to guarantee an equitable distribution of the waste resulting from the reprocessing of the fuels of its various customers, the licensee has proposed an accounting system that tracks the entries into and exits from the La Hague plant. This system, called “Exper”, was approved by the 2 October 2008 Order from the Minister responsible for energy. 1.4 “Fuel cycle” consistency in terms of nuclear safety and radiation protection The “nuclear fuel cycle” comprises the fabrication of the nuclear fuel used in the NPP reactors, its storage, its reprocessing after irradiation and management of the resulting waste. Several licensees are involved in the “cycle”: Orano, Framatome, EDF and the French National Radioactive Waste Management Agency (Andra). ASNR monitors the overall consistency of the industrial choices made with regard to fuel management and which could have consequences for safety. Over and above the safety issues specific to each facility, there are systemic safety issues affecting the “fuel cycle”, notably from the viewpoint of balancing the operation of the various facilities and managing the inventories of radioactive substances and the corresponding storage needs. On 18 October 2018, ASN issued its opinion 2018-AV-0316 on the “Impact Cycle 2016” dossier, jointly drafted with the industrial stakeholders in the “cycle”. This dossier presents the consequences for each step in the “fuel cycle” of the strategy implemented by EDF for use of different types of fuels in its reactors, different energy mix scenarios envisaged by the Multi-Year Energy Programme (PPE), or the operating contingencies of the plants involved in the “fuel cycle”. It underlines the need to anticipate any strategic change in the functioning of the “fuel cycle” by at least ten years so that it can be designed and carried out under controlled conditions of safety and radiation protection. It is a question for example – given the incompressible development times for industrial projects – of ensuring that the needs for the creation of new spent fuel storage facilities or for new transport packaging designs are addressed sufficiently early. In collaboration with Framatome, Orano and Andra, EDF annually updates its “fuel cycle” management outlook according to energy mix scenarios consistent with the guidelines of France’s energy policy. Forward-looking simulation work is regularly presented to ASNR by the licensees concerned, notably during joint hearings of Orano and EDF by the ASNR Commission. In the light of the new nuclear policy guidelines, and notably the hypothesis of continued operation of EDF’s 900 MWe reactors beyond 50 years, the licensees given a hearing presented ASN in 2024 with the projected spent fuel volumes to be stored according to the various production scenarios from the La Hague and Melox plants. In 2025, Orano and EDF presented an update of these projections, which confirmed that spent fuel storage capacity would be saturated by 2040, and that it would be necessary to increase storage density in the event of a hazard occurring between now and then. However, ASNR finds that even if the spent fuel inventories to be stored would thus appear to be stabilised until 2040, the available margins in the pools on the La Hague site remain limited over the long-term and are based on ambitious scenarios for both production and the absence of contingencies blocking the La Hague and Melox plants. ASNR therefore urges the licensees to exercise great prudence and underlines the need for the “cycle” facilities and associated storage capacities to have significant margins, in terms of operational capacity and processes, with respect to the various energy scenarios envisaged and with regard to the contingencies liable to affect the operations. In the light of the challenges relating to the risk of saturation of spent fuel storage capacity, ASNR underlines the fact that the new longterm spent fuel storage capacities planned by Orano at La Hague will have to be commissioned within the scheduled time-frame and with high-level safety objectives. ASNR notes that the provisional timetable for commissioning new spent fuel storage capacity does not provide any margin with regard to the saturation horizon for current capacity. 324 ASNR Report on the state of nuclear safety and radiation protection in France in 2025
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