On completion of decommissioning, a nuclear facility can be delicensed by an ASN resolution approved by the Minister responsible for nuclear safety. It is then removed from the list of BNIs and is no longer subject to the BNI regulatory framework. As part of its delicensing application, the licensee must provide a file containing a description of the state of the site after decommissioning (analysis of the state of the soils, remaining buildings or facilities, etc.) and demonstrating that the planned final state has been reached. Depending on the final state reached, ASN may require the implementation of active institutional controls* as a condition of delicensing the BNI in question. These may set a number of restrictions on the use of the site and buildings (use limited to industrial applications for example) or precautionary measures (radiological measurements to be taken in the event of excavations (2), etc.). Some twenty facilities, most of them old research reactors, have been decommissioned and delicensed to date. As at 31 December 2022, ASN was examining 22 decommissioning files for definitively shut down facilities whose decommissioning has not yet been prescribed or whose decommissioning conditions have substantially changed. The examination of the delicensing files of the last two BNIs of the CEA Grenoble centre is completed. 2. Excavation means the intentional digging of a plot of land by soil extraction to conduct works (for example, digging the foundations of a construction). 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. This Order 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 carried out 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 inadequate. 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 2022, 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 342). 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 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. Furthermore, one of the major decommissioning problems is the loss of memory of the design and operation of the installation. Therefore maintaining skills and the installation characterisation phase to determine its initial state (state of the installation at the start of decommissioning) are of vital importance. 2.1 Nuclear power reactors 2.1.1 Pressurised water nuclear power reactors The decommissioning of Pressurized 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. EDF 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 pressure vessel began in 2014 and is continuing satisfactorily. The Fessenheim Nuclear Power Plant (NPP) was definitively shut down in 2020. Its two reactors, which are representative of the fleet of reactors currently operated by EDF, will be first 900 Megawatts electric (MWe) reactors to be decommissioned in France. Decommissioning of the Fessenheim reactors with therefore also provide EDF with considerable experience feedback for its other PWRs (see “Regional overview” in the introduction of this report). 2.1.2 Nuclear power reactors other than Pressurised Water Reactors 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 in France or elsewhere in the world, and the fact that when they were designed, the perspective of their future decommissioning was not as fundamental a concern as it may have been for the more recent reactor series. 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. 340 ASN Report on the state of nuclear safety and radiation protection in France in 2022 • 13 • Decommissioning of Basic Nuclear Installations 13
RkJQdWJsaXNoZXIy NjQ0NzU=