ASNR’S DECISION AND REQUIREMENTS What new measures is EDF planning? EDF plans to update its safety case in light of developments in knowledge and the conclusions of investigations carried out prior to the periodic safety review. Its aim is to work towards levels of radioactive releases into the environment that do not require population protection measures (sheltering, evacuation, consumption of iodine tablets). During the generic phase of the periodic safety review, EDF reviewed all the studies associated with various accidents. In particular, EDF assessed the effects of physical phenomena not previously taken into account in the safety case, such as deformation of the nuclear fuel assemblies. EDF is also planning to modify its facilities, in particular by adding four shutdown control rods* to the reactor cores, and replacing the pump used to inject borated water into the reactor coolant pump seals. The modifications planned by EDF will improve the management of incident and accident situations not involving core melt, and will therefore also improve the prevention of core meltdown accidents. They will limit the radiological consequences of the accidents analysed in the safety case. This will significantly reduce the occurrence of situations requiring population protection measures. The results of these studies and the modifications planned by EDF will enable the objectives of the periodic safety review to be met. The ASNR’s decision Accidents without core meltdown How can the consequences be reduced? In an accident not involving core melt, little or no damage occurs to the nuclear fuel. Such accidents can, however, lead to radioactivity being released into the environment. Controlling such accidents can prevent core meltdown. The safety case for reactors covers both accidents resulting from a single failure (for example, a small break in the primary cooling system) and accidents resulting from multiple and cumulative failures (for example, loss of on-site and off-site power). 20 • Les cahiers de l’ASNR • July 2025
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