With the final shutdown of a large number of installations in recent years, the major nuclear licensees are faced with having to carry out several decommissioning projects at the same time. To obtain an overview of these various projects and how they interface with each other, ASN examines the licensees’ decommissioning and waste and materials management strategies. EDF is the licensee of the French nuclear fleet, consisting of 56 PWR reactors in operation in 18 NPPs and it also has to manage the decommissioning a dozen installations. The gas-cooled reactor (GCR) decommissioning strategy EDF’s first generation of nuclear reactors are of the GCR type, operating with natural uranium. The first GCR reactor was commissioned at Chinon (Indre-et-Loire département) in 1963. A total of six reactors of this type were built in France. These reactors were shut down between 1973 and 1994, when this technology was abandoned. The fuel, which accounted for the vast majority of the risk to the safety of these installations, has been removed. However, some of these installations were only partially decommissioned before being placed under surveillance, pending final dismantling. The pertinence of “immediate” dismantling of nuclear installations was in fact only recognised by all players in the early 2000s. An initial scenario studied by EDF consisted in filling the reactor core with water so that the decommissioning operations could be carried out, thus mitigating the radioactivity risks. EDF originally planned to complete decommissioning of these reactors between 2024 and 2031. 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 Licensee decommissioning strategies assessed by ASN Decommissioning strategies appropriate to the reactor model and changing technologies * See glossary page 30 12 • Les cahiers de l’ASN • June 2022 BNIs BEING DECOMMISSIONED
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