The MOX fuel is fabricated in BNI 151 Melox, operated by Orano and located on the Marcoule nuclear site, by mixing uranium oxide and plutonium oxide powder and sintering it into pellets, which are then placed in cladding and assemblies of the same geometry as those produced by FBFC. 1.3 The back-end fuel cycle – reprocessing The Orano reprocessing plants in operation at La Hague The La Hague plants, intended for reprocessing of spent fuel assemblies from nuclear reactors, are operated by Orano. The various facilities of the plants reprocessing irradiated fuel elements from ordinary water nuclear reactors (UP3-A – BNI 116 and UP2-800 – BNI 117) and of the Effluent Treatment Station (STE3 – BNI 118) were commissioned from 1986 (reception and storage of spent fuel assemblies) to 2002 (R4 plutonium reprocessing facility), with most of the process facilities being commissioned in 1989-1990. The Decrees of 10 January 2003 set the individual reprocessing capacity of each of the two plants at 1,000 tonnes per year (t/year), in terms of the quantities of uranium and plutonium contained in the fuel assemblies before burn-up (in the reactor), and limit the total capacity of the two plants to 1,700 t/year. The limits and conditions for water discharges and intake defined in 2015, were updated by two ASN resolutions of 16 June 2022 (resolution 2022-DC-0724 and resolution 2022DC-0725). The resolutions notably modify the maximum monthly value of the activity concentration of the noble gases, including krypton-85, and regulate the limits and procedures for the discharge at sea of eleven chemical substances, detected by the licensee in small quantities in the discharges during a regulatory conformity evaluation. Operations carried out in the plants The reprocessing plants comprise several industrial units, each of which performs a specific operation. Consequently, there are facilities for the reception and storage of spent fuel assemblies, for their shearing and dissolution, for the chemical separation of fission products, uranium and plutonium, for the purification of uranium and plutonium, for treating the effluents and for vitrification and conditioning the waste. When the spent fuel assemblies arrive at the plants in their transport casks, they are unloaded either “under water” in the spent fuel pool, or dry in a leaktight shielded cell. The fuel assemblies are then stored in pools for several years, for cooling. 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. “Fuel cycle” diagram Fuel fabrication Enrichment 1st conversion 2nd conversion Interim storage Spent MOX interim storage Extraction of ore Interim storage pending final disposal MOX Fabrication Nuclear reactor The tonnages shown on the diagram correspond to “nominal” operation, which has not been seen in recent years. Reprocessed uranium spent MOX 110 t Plutonium Reprocessed uranium Fission products Technological waste Depleted uranium Flows expressed in tonnes/year 7,500 t 940 t 10 t 1,000 t 120 t 1,000 t 120 t 1,000 t 8,500 t 338 ASN Report on the state of nuclear safety and radiation protection in France in 2024 “Nuclear fuel cycle” facilities
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