ASN authorised the first phase of the work to retrieve the sludges from STE2 in 2015. The Creation Authorisation Decree for STE3 was modified by the Decree of 29 January 2016 to allow the installation of the STE2 sludges treatment process. At the end of 2017 however, Orano informed ASN that the process chosen for treating the sludges in STE3 could lead to difficulties in equipment operation and maintenance. Orano proposed an alternative scenario using centrifugation and in August 2019 it submitted a Safety Options Dossier (DOS), which is however based on as yet insufficiently substantiated hypotheses. An inspection conducted at the end of 2019 confirmed that the project was not sufficiently mature for ASN to be able to give an opinion on this DOS. In 2022, during the technical discussions held between Orano, ASN and IRSN, Orano committed itself to a new roadmap for this project. Orano has thus abandoned the centrifugation scenario and undertaken to conduct new studies in parallel aiming firstly to look into the sludge treatment and packaging solutions in more detail, and secondly to put in place an intermediate storage facility (new silos) under suitably safe conditions, enabling the retrieval and safe storage of these sludges to be separated from their final packaging. Orano sent ASN the DOS associated with this project to create new sludge storage silos (project called “NABUCO”) in December 2023. After expert appraisal and assessment, ASNR stated its position on these safety options in January 2025. Silo 130 Silo 130 is a reinforced concrete underground storage facility, with a carbon steel liner, used for dry storage of solid waste from the reprocessing of Gas-Cooled Reactor (GCR) fuels, and the storage of technological waste and contaminated soils and rubble. The silo received waste of this type as from 1973, until the 1981 fire which forced the licensee to flood the waste. The leak-tightness of the water-filled silo is only ensured at present by a single containment barrier consisting of a steel “skin”. Furthermore, the civil engineering structure of silo 130 is weakened by ageing and by the fire that occurred in 1981. The water is therefore in direct contact with the waste and can contribute to corrosion of the carbon steel liner. One of the major risks for this facility concerns the dispersion of radioactive substances into the environment by infiltration of contaminated water into the water table. The leak-tightness of silo 130 is monitored by a network of piezometers situated nearby. Another factor that can compromise the safety of silo 130 is linked to the nature of the substances present in the waste, such as magnesium, which is pyrophoric. Hydrogen, a highly inflammable gas, can also be produced by phenomena of radiolysis or corrosion (presence of water). These elements contribute to the fire and explosion risks. The WRP scenario comprises four steps: • retrieval and packaging of the solid GCR waste; • retrieval of the liquid effluents; • retrieval and packaging of the residual GCR waste and the sludges from the bottom of the silo; • retrieval and packaging of the soils and rubble. Continuity and Resilience Project Orano La Hague’s spent fuel reprocessing plants are unique facilities in France. They were mainly commissioned between 1980 and 2000. With the aim of keeping these plants in operation until 2040, Orano has implemented a programme to monitor the ageing of the facilities, known as the “Ageing Compliance Review”. This programme was examined by ASNR as part of the periodic safety review and inspection process. At the Nuclear Policy Council in February 2024, it was announced that the reprocessing of spent nuclear fuel would continue beyond 2040. To this end, the continued operation of the La Hague plants is now envisaged as continuing beyond 2040 and up to 2050-2060, corresponding to the periods envisaged for the commissioning of the new reprocessing plants under the “Future Back-End” programme. In 2024, Orano therefore launched a programme called “Continuity/Resilience”, the scope and objectives of which go beyond the “Ageing Compliance Review” programme. This programme involves considering a much larger volume of technical items and a much longer timescale than the ten-yearly periodic safety reviews of the installations concerned. The aim of the Continuity section is to ensure the reliability and continued safe operation of the facilities. It begins with a diagnostic phase for identifying the technical items whose failure or shutdown would jeopardise the facilities’ ability to carry out the expected production programme. This identification phase covers not only sheet metal equipment, but also civil engineering, cables, piping, etc. Around a million technical objects need to be examined. Once the equipment concerned has been identified, it will be analysed in terms of how it ages and its remaining service life. Specific action plans will then be implemented to repair, reinforce or replace them if necessary, so that they can continue to operate until the set deadline. The Resilience component is designed to secure and guarantee a safe level of fuel reprocessing. It is based on an analysis of the risks of plant failure, followed by the identification of solutions to deal with them. In this context, Orano is studying several projects designed to provide redundant equipment for the operation of the plants or to enable stronger interconnections between the two existing plants. Since April 2024, Orano has been periodically presenting to ASNR the principles and progress of the work it has undertaken as part of this programme. In November 2025, ASNR carried out an initial inspection of the continuity aspect and, more specifically, of the identification phase of the technical objects to be examined. This highlighted the important work already carried out by Orano’s teams, but ASNR noted the need to formalise the methodology used and the traceability of the work carried out. In 2026, ASNR will step up technical exchanges with Orano, and several inspections will be carried out on this programme to assess its completeness and the robustness of the actions implemented. Normandie ABSTRACTS – ASNR Report on the state of nuclear safety and radiation protection in France in 2025 77
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