announced that the “under water*” dismantling scenario was no longer the reference solution, resulting in a change in strategy. EDF thus opted for an “in air*” dismantling scenario, eliminating the problems linked to the use of water. This change entailed a significant postponement in the dismantling operations. EDF decided to use an industrial demonstrator to validate certain complex operations, followed by complete dismantling of one reactor vessel before beginning dismantling of the other five vessels. EDF has also significantly increased the time needed to decommission a reactor. The PWR decommissioning strategy The current French NPP fleet consists entirely of PWRs. They operate with enriched uranium. Considerable experience feedback from the decommissioning of these reactors has been acquired through numerous projects internationally: 42 reactors of this type are currently undergoing decommissioning around the world, and 6 have already been decommissioned in the United States. There are thus no major technical issues regarding the feasibility of the decommissioning operations which, according to international experience feedback, last about twenty years. They start following the issue of the decommissioning decree, which sets out the main steps: in the reactor building, removal of the primary system after any necessary decontamination, followed by cutting of the reactor pressure vessel. The systems of the other buildings of the nuclear island are also decontaminated at the same time. After removing all dismantled equipment and waste, the licensee continues with clean-out of the various buildings and then their demolition, with a view to delicensing* of the BNI* and remediation of the site. In France, the first decommissioning decree for a PWR concerned the Chooz A reactor, installed in a cavern in the Ardennes mountains, in 2007. The next one will concern the Fessenheim NPP. ASN’S POSITION • For the GCRs, ASN duly notes the difficulties being encountered for continued decommissioning “under water*” and considers the scenario change to be acceptable. It will examine the safety of the operations to be carried out “in air*” and the corresponding time-frames. In resolutions of March 2020, and following public consultation, ASN instructed EDF to submit an application file for modification of the existing decommissioning decrees for the Bugey 1, Saint-Laurent A1 and A2 and Chinon A3 reactors, and to submit the decommissioning files for those reactors as yet not covered by one (Chinon A1 and Chinon A2), no later than the end of 2022. ASN also indicated that EDF will need to shorten the decommissioning time-frames set out in its strategy, in order to meet the legislative obligation for decommissioning in a period as short as possible for each reactor. Finally, in order to make the reactor decommissioning schedule more reliable, ASN asks EDF to identify adequate waste management routes which could, if necessary, lead to the creation of new waste storage facilities. • For the PWRS, whatever the service life of the reactors currently in operation, EDF will be faced with the simultaneous decommissioning of several PWRs in the coming years. 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. Decommissioning of the Fessenheim NPP will provide useful industrial feedback in this respect. For more information, scan this QR code. Decommissioning challenges • 13
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