Les cahiers de l’ASN #02 - Conditions for the continued operation of EDF’s 900MWe reactors

Work to enhance safety A SN asks EDF to carry out the majority of the safety improvements before submitting the safety review concluding report for each reactor, which in practice means during the 10-yearly outage of each reactor. The other improvements must be carried out within 5 years at the most after submitting this report. For the majority of the reactors, EDF plans performing this work within 3 years following submission of the concluding report. These time frames are extended for the first reactors to undergo their periodic safety review on account of the necessary preparation time. More specifically, all the improvements must be carried out within 6 years for the Tricastin1 and 2, Bugey 2, 4 and 5, Gravelines1 and Dampierre1 reactors. This staggering is linked to the scale of the works on each reactor, which will moreover be carried out concurrently on several 900MWe reactors. It takes into account the ability of the industrial fabric to conduct the works with the required standard of quality and the associated training necessary for the operators to familiarise themselves with these changes. Other requirements have a deadline that is common to all the reactors. For example: End 2024: special tests on the Blayais, Chinon, Cruas-Meysse, Dampierre- en-Burly, Gravelines, Saint-Laurent- des-Eaux and Tricastin reactors End 2024: reassessment of organisational and human factors End 2025: special tests on the Bugey reactors End 2027: replacement of heat insulation that could release fibres in the event of a break in the primary system containment 6 • Les cahiers de l’ASN • February 2021 4 TH PERIODIC SAFETY REVIEW OF THE 900MW e REACTORS