measures (radiological measurements to be taken in the event of undermining(3), etc.). Some twenty facilities, most of them old research reactors, have been decommissioned and delicensed to date without being attached to a BNI or an Installation Classified for Protection of the Environment (ICPE). As at 31 December 2021, ASN was examining 19 decommissioning files for definitively shut down facilities whose decommissioning has not yet been prescribed or whose decommissioning conditions have been substantially changed. It is also examining two delicensing files for facilities whose decommissioning operations have been completed. 1.4 The financing of decommissioning and radioactive waste management Articles L. 594-1 to L. 594-10 and D. 594‑1 to D. 594‑18 of the Environment Code define the system for ring-fencing funds to cover the costs of decommissioning nuclear facilities and managing the spent fuel and radioactive waste. This system is clarified by the Order of 21 March 2007 relative to securing the funding of the nuclear costs. 3. Undermining means the intentional excavation of a plot of land by soil extraction to conduct works (for example, digging the foundations of a construction). It aims to secure the funding for nuclear costs applying the “Polluter-pays” principle. It is therefore up to the nuclear licensees to take charge of this financing by setting up a dedicated portfolio of assets capable of covering the expected costs. These costs must be evaluated conservatively, taking the various uncertainties into account. The licensees are thus obliged to submit triennial reports on these costs along with annual update notices to the Government. Provisioning is ensured under direct control of the State, which analyses the situation of the each licensee and can prescribe the necessary measures should it be found to be insufficient or inappropriate. The General Directorate of the Treasury (DGT) and the General Directorate for Energy and the Climate (DGEC) constitute the administrative authority with competence for this control. The DGEC asks ASN to issue a technical opinion on the hypotheses adopted by the licensees. Whatever the case may be, the nuclear licensees remain responsible for the satisfactory financing of their long-term costs. 2 // Situation of nuclear facilities undergoing decommissioning: specific challenges At the end of 2021, 35 nuclear facilities in France are definitively shut down or undergoing decommissioning, that is to say about a quarter of the BNIs (see map page 334). These facilities are varied (nuclear power reactors, research reactors, “fuel cycle” facilities, support facilities, etc.) and the decommissioning challenges can differ greatly from one facility to the next. These risks are nevertheless all linked to the large quantity of waste to be managed during decommissioning and to the need to work very close to contaminated or activated zones. The risks for safety and radiation protection are all the higher if the facilities contain legacy waste; this is the case, in particular, with the Orano former spent fuel reprocessing plants and the CEA’s old storage facilities. 2.1 Nuclear power reactors 2.1.1 Pressurised water nuclear power reactors The decommissioning of Pressurised Water Reactors (PWRs) benefits from experience feedback from numerous projects across the world and the design of these reactors facilitates their decommissioning compared with other reactor technologies. The decommissioning of this type of installation presents no major technical challenges and its feasibility is guaranteed. Nevertheless, whatever the service life of the reactors in operation, EDF will be confronted with the simultaneous decommissioning of several PWRs in the coming years, and will therefore have to organise itself to industrialise the decommissioning process, in order to meet the requirement to decommission each installation in the shortest time possible. The first PWR decommissioning work site in France is the Chooz A reactor (BNI 163). This is a small model compared with the nuclear power reactors in operation. It presents some specific technical difficulties due to its construction inside a cavern. This makes some operations more complex, such as the removal of large components like the steam generators. Decommissioning of the Chooz A reactor vessel has been in progress since 2014 and should continue within the prescribed time frames. The Fessenheim Nuclear Power Plant (NPP) was definitively shut down in 2020. Its two reactors will be the first 900 Megawatts electric (MWe) reactors to be decommissioned in France. Decommissioning of the Fessenheim reactors will thus provide EDF with considerable experience feedback for its other PWRs. 2.1.2 Nuclear power reactors other than PWRs The nuclear power reactors that are not PWRs are all industrial prototypes. These comprise the first-generation Gas-Cooled Reactors (GCRs), the EL4-D heavy water reactor on the Brennilis site, and the sodium-cooled fast breeder reactors Phénix and Superphénix. The decommissioning of these reactors is characterised by the lack of prior experience at national (France) or international level. In view of their unique nature, specific and complex operations have to be devised and carried out to decommission them. Furthermore, some of these reactors have been shut down for several decades, which has led to loss of knowledge of the installation and its operation and loss of the associated skills. As with the PWRs, decommissioning begins with the removal of the nuclear fuel, which removes 99% of the radioactivity present in the installation. As the thermal powers of these reactors is relatively high (all greater than 250 Megawatts thermal –MWth), their decommissioning requires the use of remotely operated means in certain highly irradiating zones (reactor core). The GCRs have the particularity of being extremely massive and large-sized reactors, necessitating innovative cutting and access techniques under highly irradiating conditions. The decommissioning of these reactors will oblige EDF to manage significant volumes of waste. The final disposal route for some of this waste is currently being determined, such as the graphite bricks, representing some 15,000 tonnes of waste that will be produced, for which disposal appropriate for low-level long-lived nuclear waste (LLW-LL) is envisaged. Decommissioning of the prototype heavy water reactor (EL4-D) has been slowed down, firstly due to the lack of prior experience in the decommissioning techniques to use, and secondly due to difficulties concerning Iceda, the Conditioning and Storage Facility for Activated Waste (see the Regional Overview in the introduction to this report), which must take in some of this decommissioning waste. 332 ASN Report on the state of nuclear safety and radiation protection in France in 2021 13 – DECOMMISSIONING OF BASIC NUCLEAR INSTALLATIONS
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