Finally, for the fourth periodic safety review of the 900 MWe reactors, EDF has updated its safety case regarding internal flooding risks, notably by considering several possible water flow routes, and has defined additional provisions to mitigate the risks. Seismic risks The inspection programmes implemented by EDF lead it to regularly report significant safety events owing to the lack of seismic resistance of certain equipment. These events are the result of targeted inspections gradually being deployed by EDF. These non-compliances can have serious consequences in the event of an earthquake and they are thus systematically analysed. On 11 November 2019, an earthquake occurred in the municipality of Le Teil (Ardèche département). Following this earthquake, EDF implemented the operating procedure required in the event of an earthquake on the Cruas-Meysse NPP. This was because the seismic motion detected on this site reached the level requiring shutdown of the reactors so that checks could be carried out. An inspection programme was then defined and carried out before the reactors were restarted. In November 2019, ASN asked EDF to determine whether this earthquake should lead to a revision of the seismic levels to be adopted for protection of the Tricastin and Cruas-Meysse NPP sites. According to EDF, the Le Teil earthquake has no impact on the seismic level adopted for protection of the Tricastin site, but that of Cruas-Meysse should be re-evaluated. This re-evaluation requires additional field investigations and should be completed in 2022. Pending the results of these investigations, EDF defined a new, temporary design-basis spectrum. This spectrum will be used to initiate the seismic re-evaluation studies associated with the fourth periodic safety review of this site. ASN will issue a position statement on this subject in 2022. Risks linked to extreme temperatures The inspections concerning the risks associated with extreme temperatures show that EDF’s organisation must be improved on the majority of sites. On several sites, ASN more particularly found a lack of forward planning in preparing the facility for the summer or winter configuration, which led to corrective action requests. In recent summers, at ASN’s request, EDF ran operating tests on the emergency diesel generator sets during a period of high temperatures. The purpose of these tests is to confirm the qualification demonstration of this equipment. Lightning risks The inspections relating to lightning risks reveal the need on all sites to set up reinforced organisation and oversight to improve the integration of the regulatory requirements associated with the management of this hazard. Corrective measures have been requested. ASN still observes shortcomings in the lightning risk management approach, notably in the dedicated risk assessments, which regularly contain incorrect information regarding the state of the installations. ASN also observes significant delays in the performance of the work identified in the technical studies. Moreover, the deadlines for performance of the periodic checks on the lightning protection systems by the competent inspection organisations are not always met. These points were the subject of requests for corrective action. EDF has defined a programme of work to improve the situation. THE DEFINED REQUIREMENTS The Order of 7 February 2012 stipulates that a defined requirement is a “requirement assigned to an item of Protection Important Component (of persons and the environment), so that, with the expected characteristics, it can perform the function stipulated in the safety case, or to an activity important for protection (of persons and the environment) so that it meets its objectives with respect to this safety case”. For the equipment, these requirements may in particular concern: ཛྷ the characteristics of the materials used; ཛྷ the manufacturing, assembly, erection and repair processes; ཛྷ the physical parameters and criteria characteristic of the performance of the equipment. For the activities, these requirements may in particular concern: ཛྷ the skills needed to perform the activity; ཛྷ any qualifications necessary; ཛྷ checks and hold points; ཛྷ the equipment and hardware needed to enable the activity to be carried out in accordance with the regulatory or even contractual requirements, such as to guarantee compliance with the safety case. PROCESSING OF DEVIATIONS A deviation is a non-compliance with a defined requirement or a requirement set by the licensee’s integrated management system. A deviation may thus affect a structure, a system or a component of the facility. It may also concern compliance with an operating document or the working of an organisation. The regulations require that the licensee identify all deviations affecting its facilities and process them. The activities related to the processing of deviations are activities important for the protection of persons and the environment. They are thus subject to oversight and monitoring requirements, the implementation of which is regularly checked by ASN. REINFORCED OVERSIGHT OF SUPPLIERS OF EQUIPMENT IMPORTANT FOR NUCLEAR SAFETY In 2021, ASN reinforced its oversight of the EDF procurement chain for equipment important for safety intended for NPPs. In 2021, ASN therefore carried out 42 inspections, most of them in manufacturing plants. During these inspections, ASN examined compliance with the regulatory requirements during manufacturing operations, the ability of the suppliers to manufacture equipment meeting the safety requirements and how the risk of fraud is addressed. During these inspections, ASN also checked EDF’s monitoring of its suppliers and their subcontractors. ASN in particular took part in multinational inspections with its foreign counterparts under the Multinational Design Evaluation Programme (MDEP) in Framatome’s Saint-Marcel plant (Saône-et-Loire département), Flowserve’s Raleigh plant (United States) and the Fairbanks plant in Beloit (United States). 294 ASN Report on the state of nuclear safety and radiation protection in France in 2021 10 – THE EDF NUCLEAR POWER PLANTS
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