ASN Report 2020

ASN also instructed EDF to submit a report on the activities of the industrial demonstrator, the construction of which began in the fourth quarter of 2020. ASN also instructed EDF to carry out decommissioning of the rooms and equipment situated around the vessel, which has already been authorised and remains unchanged. Only the reactor vessel decommissioning operations have been revised and prove to be more complex than initially envisaged. The other decommissioning operations shall therefore be carried out as soon as possible. EDF shall regularly inform ASN of the progress of its studies and work. Finally, in order to make the reactor decommissioning schedule more reliable, ASN asked EDF to choose robust waste management routes which could , if necessary, lead to the creation of new waste storage facilities. Given the major technical difficulties (tightness of the reactor vessel and treatment of the contaminated water), but also technological progress which has identified other solutions, remote-operation in particular, EDF in 2016 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 also entailed a significant postponement in the dismantling operations on these reactor vessels. EDF felt that the feasibility of certain complex operations (such as cutting very thick concrete or the use of tools attached to an articulated arm required to descend to a depth of 20 metres) needed to be validated with an industrial demonstrator, followed by complete dismantling of one reactor vessel before beginning dismantling of the other five vessels. Given the results of the studies conducted, EDF has also significantly increased the time needed to decommission a reactor. ASN duly notes the difficulties encountered with continued dismantling “under water” and, via the decommissioning files for the GCR reactors, it will study the safety of the “in air” operations planned and the corresponding deadlines. After examining a number of substantiation files, holding a hearing of EDF and carrying out inspections on the subject, ASN considers that the production of an industrial demonstrator for this new dismantling technique is relevant, notably in order to qualify the tools for use in harsh conditions. However, ASN considers that waiting for the end of decommissioning of a first reactor vessel and analysis of the lessons learned – which would not happen until about 2060-2070 – before starting to decommission the other reactor vessels, is not acceptable with regard to the obligation of dismantling within the shortest possible time-frame. After consultation of the public, the ASN resolutions of March 2020 ordered EDF to submit a file requesting changes to 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 which did not already have one (Chinon A1 and Chinon A2), no later than the end of 2022. ASN also stated that EDF must in particular shorten the decommissioning time-frame set out in its 2016 strategy, in order to meet the legislative obligation for dismantling in as short a time as possible for each reactor. Remote-operated telescopic tool carrier arm for dismantling inside the reactor vessels Dismantling platform Heat exchangers Stacks of graphite bricks “Integrated” type GCR reactor dismantling principle ASN duly notes the diff iculties encountered with continued dismantling “under water” and [….] it will study the safety of the “in air” operations planned and the corresponding deadlines ASN Report on the state of nuclear safety and radiation protection in France in 2020 31 NOTABLE EVENTS 2020