ASN Report 2023

Bretagne REGION The Nantes division regulates radiation protection and the transport of radioactive substances in the 4 départements of the Bretagne region. The Caen division regulates the nuclear safety of the Brennilis Nuclear Power Plant (NPP), currently undergoing decommissioning. In 2023, ASN carried out 48 inspections, two at the Monts d’Arrée NPP currently being decommissioned, one to monitor an approved laboratory, three in the transport of radioactive substances and 39 in small-scale nuclear activities (22 in the medical sector and 17 in the industrial, veterinary and research sectors). BRENNILIS NUCLEAR POWER PLANT The Brennilis NPP is situated in the Finistère département, on the Monts d’Arrée site 55 km north of Quimper. Baptised “EL4-D”, this installation (BNI 162) is an industrial electricity production prototype (70 Megawatts electric – MWe), moderated with heavy water and cooled with carbon dioxide, and it was definitively shut down in 1985. Decree 2011-886 of 27 July 2011 authorised the NPP decommissioning operations, with the exception of the reactor block. In July 2018, EDF submitted an application file for the complete decommissioning of its facilities, and this file was subject to a public inquiry from 15 November 2021 to 3 January 2022. Decree 2023-0898 of 26 September 2023, published on 28 September 2023, requires EDF to completely decommission BNI 162 and amends Decree 96-978 of 31 October 1996 authorising the creation of this facility. The Decree sets the radiological cleanliness targets, and future ASN resolutions will govern the methods of post-operational clean-up of the site, which shall be taken as far as is reasonably achievable. The end-of-commissioning date is set at 2041. In April 2023, ASN issued the authorisation to stop the lowering of the water table underneath the effluent treatment station. During 2023, ASN also continued the revision of the resolutions governing discharges and water intakes and the examination of the general operating rules and the on-site emergency plan for the complete decommissioning. During the same year, EDF continued its preparatory work for complete decommissioning, in particular with the removal of asbestos from the accessible places and the civil engineering work to enlarge the existing accesses and demolish bunkers. EDF also started the work to treat the water infiltrations in the facilities, which concern the “G7” gallery in particular. Alongside this, EDF has started execution studies for certain complete decommissioning operations (such as the decommissioning of the peripheral circuits) and for upgrading the support functions that are absolutely necessary for complete decommissioning (handling cranes, ventilation in the reactor containment, etc.). ASN notes that the November 2023 storm “Ciaran” had no impact on the safety of the NPP. The decommissioning operations were stopped on 2 November 2023 due to an outage of the site’s main electrical power supply, and resumed on 6 November 2023. The installations and activities to regulate comprise: • the Basic Nuclear Installation:: • the Monts d’Arrée (Brennilis) NPP, undergoing decommissioning; • small-scale nuclear activities in the medical sector: •10 external-beam radiotherapy departments, • 5 brachytherapy departments, •10 nuclear medicine departments, •38 centres performing fluoroscopy-guided interventional procedures, • 63 computed tomography scanners for diagnostic purposes, • some 2,500 medical and dental radiology devices; • small-scale nuclear activities in the industrial, veterinary and research sectors: •1 cyclotron, •16 industrial radiography companies, including 3 performing gamma radiography, • 25 research units, • about 400 users of industrial equipment; • activities associated with the transport of radioactive substances; • ASN-approved laboratories and organisations: • 8 organisations approved for measuring radon, •3 head-offices of laboratories approved for taking environmental radioactivity measurements. Chapter 7 p. 204 Chapter 8 p. 240 Chapter 9 p. 270 46 ASN Report on the state of nuclear safety and radiation protection in France in 2023

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