ASN Report 2020

Gas-Cooled Reactor decommissioning strategy EDF’s first-generation nuclear reactors are Gas-Cooled Reactors (GCRs), which operate using natural uranium as a fuel. This operation differs from that of Pressurised Water Reactors –PWR ( see chapter 10 ), which form the entirety of the current French NPP fleet and operate with enriched uranium. The first GCR reactor was commissioned at Chinon in 1963. A total of six reactors of this type were built in France: at Chinon (Chinon A1, A2 and A3), Saint-Laurent- des-Eaux (Saint-Laurent A1 and A2) and Bugey (Bugey 1). These reactors were shut down between 1973 and 1994, as this technology was replaced by the PWR. The fuel, which represented virtually the entire safety risk in 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. Since then, this notion became law in 2015, with the Environment Code now requiring “dismantling as rapidly as possible”. A change in decommissioning strategy EDF has not as yet provided any demonstrations such as to permit authorisation of the next stages in the decommis­ sioning of the ChinonA1 and A2 reactors. The other four GCR reactors (Bugey1, Chinon A3, Saint-Laurent A1 and A2) have received decommissioning authorisation, in accordance with a scenario set out by EDF in the early 2000s. This scenario was to fill the reactor core (or vessel) with water in order to perform the decommissioning operations , to reduce the ionising radiation risks. EDF initially planned to complete decommissioning of these reactors in 2024, 2027 and 2031 respectively. Bugey GCR reactor 30 ASN Report on the state of nuclear safety and radiation protection in France in 2020 DECOMMISSIONING