ASN conducted four inspections in 2023. They focused in particular on the primary cooling system of the reactor for the aspects relating to correction of the deviations detected on the heat exchangers and taking into account the risk of migrating bodies, on the water-proofing of the floors and walls, and correcting the deviation concerning the severing of several reinforcing bars of a slab in the leak collection zone. The assembly of the reactor equipment and of the fluid circuits, the lining of the pools, the treatment of the corrosion at the bottom of the reactor pool and the fire protection of the nuclear buildings also underwent verifications. Following the submittal in late 2021 of a revision of the facility’s safety analysis report taking into account the changes and modifications introduced since the start of construction, ASN – assisted by the Institute of Radiation Protection and Nuclear Safety (IRSN) – continued the technical examination of various themes in 2023 in preparation for the future commissioning. ASN notes the rigour of the organisation put in place the construction of the JHR and underlines the effective and satisfactory handling of the main deviations detected on the worksite. A project completion road map has been produced by the CEA, with a new reference schedule for the construction and commissioning of the facility. The Nuclear Policy Council meeting of 19 July 2023 endorsed the continuation of the investments by the State and the nuclear sector to finalise construction of the JHR, with commissioning expected around 2032-2034. In September 2023, the CEA submitted a new request to modify DAC 2009-1219 of 12 October 2009, to set the commissioning date to 14 October 2037 at the latest, taking into account margins for the project. ITER The International Thermonuclear Experimental Reactor (ITER – BNI 174), under construction on the Cadarache site since 2010 and adjacent to the CEA facilities, will be a fusion experimental reactor used for the scientific and technical demonstration of the control of thermonuclear fusion energy obtained by magnetic confinement of a deuteriumtritium plasma during long-duration experiments with a significant power level (500 MW developed for 400 seconds). This international project enjoys financial support from China, South Korea, the United States, India, Japan, Russia and the European Union, who make in-kind contributions by providing equipment for the project. The large quantities of tritium that will be brought into play in this installation, the intense neutron flow and the resulting activation of materials have serious implications regarding radiation protection and will represent true challenges for the safe management of waste during the operation and decommissioning of the installation. In 2022, ITER Organization (IO) announced its intention to develop a new “baseline “ for the project, and in 2023 it detailed the main directions the baseline would take. These directions take into account in particular the difficulty for the licensee to provide a completed safety case for the project as a whole with its different phases, given that, due to the experimental nature of the facility and its unprecedented scientific ambition, the technical and scientific knowledge expected from its first experimental phases is necessary to prepare the subsequent phases. More specifically, the new baseline would reportedly include a modified scheduling of the “plasma phases”, comprising a first phase – without fusion – with an increased technical scope, while a specific hold point would be planned after the first experimental fusion phase at reduced power, before starting the last phase with the power levels planned for in the project objectives. Several technical choices should also be modified, such as the planned replacement of beryllium by tungsten as the lining material for the first wall of the vacuum chamber. The approach proposed by the licensee to establish the safety case for its facility should be revised accordingly, with in particular a “step-by-step” method corresponding to the successive phases of commissioning and operation. ASN is not opposed to the planned method involving a safety case comprising several steps. ASN does however underline that this approach presents a significant industrial risk, should the technical choices made and the knowledge acquired at a given stage finally not enable the licensee to demonstrate control of the safety and radiation protection risks for the subsequent steps. Once the IO has finished redefining its experimentation programme and the changes to its facilities, ASN will be able to redefine the examination programme and scheduling accordingly and analyse the impact of the planned modifications. The works on the site and the manufacture of the equipment continued in 2023, except for the work on the tokamak, stopped on account of construction deviations in the first sectors of the vacuum chamber which necessitate repairs before they are installed and assembled, and the problem of stress corrosion in the thermal shield cooling systems, which also makes it necessary to repair or replace some of the equipment items concerned. Corrective actions for these various problems are currently being defined. The first sector installed in the tokamak pit in May 2022 was removed in 2023 to go back onto one of the Sector Sub-Assembly Tools (SSAT) in the assembly hall. This will allow the necessary repair operations to be carried out. As the vacuum chamber constitutes a Nuclear Pressure Equipment (NPE) item and a PIC, particularly due to the containment of radioactive substances, the sector repair procedures and the qualification of these processes will be carefully verified by ASN. ABSTRACTS – ASN Report on the state of nuclear safety and radiation protection in France in 2023 95 Regional overview of nuclear safety and radiation protection • PROVENCE-ALPES-CÔTE D’AZUR •
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