As in previous years, the periodic tests were the origin of several significant events. The main causes of these significant events are incorrect specification of the test rules in the operating documents, errors in application of the test rule when performing tests, inconsistent uncertainty values between the operating documents and methodology guides, the use of a test procedure associated with an inappropriate reference document, or periodic test programming errors. With regard to OEF from these events, EDF is adapting its organisations to ensure better sharing of information between the various actors responsible for defining, programming and carrying out tests. The Independent Safety Organisation During its inspections, ASN examines the actions of the Independent Safety Organisation – FIS (see box opposite) and checks that its opinions are correctly taken into account by the operational departments. The inspectors were able to observe the competence, good working and independence of the FIS in 2022. On several sites, it did however find too few safety engineers in place; EDF must take steps to ensure a sufficient number of safety engineers, so that they can perform their independent verification of reactor safety in optimal conditions. Operation in an incident, accident, or severe accident situation ASN checks the processes to draft and validate the incident or accident operating rules, their pertinence and how they are implemented. ASN thus carried out several inspections in 2022 on the organisational and technical arrangements made by EDF to deal with an incident and accident situation. These inspections almost always include a situational exercise for the facility’s control teams in the room or on a simulator, to check the application of instructions and intervention and communication practices within these teams. In 2022, ASN thus carried out reactive inspections on the sites where the control of the installations had been disrupted by operating contingencies; these inspections aimed to verify compliance with the applicable procedures in the management of these contingencies. Following these inspections, ASN considered the implementation of the incident or accident operating provisions to be satisfactory. Nonetheless, ASN found that the operating documents still contain errors and imprecisions, despite the considerable work done by EDF’s national engineering teams to correct them. ASN will remain attentive to ensuring correct implementation of the processes to verify the operating documents and process the anomalies detected. Emergency organisation When the situation in the facility deteriorates or additional means are needed to manage the situation, the incident or accident operating procedures provide for activation of the PUI, which leads to deployment of an emergency organisation. In 2022, three NPPs activated their emergency organisation, described in the PUI. In February, the PUI was activated by the Cruas-Meysse NPP following a fire outside the limited access area. In October, the Cattenom NPP activated its PUI following a localised ammonia release on the site. Finally, in November, the PUI was activated by the Gravelines NPP following a fire outside the limited access area. These three situations did not require any population protection measures. In 2022, six national exercises, notably involving ASN, were held in certain NPPs (Cattenom, Dampierre-en-Burly, Cruas-Meysse, Paluel, Saint-Alban and Flamanville). These were able to test the emergency organisation on these sites, as well as the exchanges with the authorities. ASN also carried out several inspections on the emergency organisation and resources, some of which entailed an unannounced situational exercise leading to activation of the site’s emergency organisation. These inspections were an opportunity to test the operational nature of the NPPs’ emergency organisation on specific topics (resilience of the organisation, equipment used by the teams during emergency situations, documentation, training, etc.). Overall, these exercises and inspections demonstrated that the EDF sites have assimilated the principles of organisation, preparation and management of emergency situations to the extent that they can take the required action in the event of an emergency. ASN also underlines the true professionalism and considerable motivation of the on-call personnel mobilised. However, EDF must continue with its training efforts concerning adoption of the “incremental” method, which should enable it to perform its duties with fewer personnel, as a result of problems with accessing the site following a hazard of extreme intensity. Finally, the through life support for a certain number of emergency rooms and certain resources deployed in an emergency situation must also be reinforced. 2.4.3 Maintenance of the facilities Preventive maintenance is an essential line of defence in ensuring the conformity of a facility with its baseline safety requirements. In order to improve the reliability of the equipment important for safety but also industrial performance, EDF is optimising its maintenance activities, drawing on practices used in conventional industry and by the licensees of NPPs in other countries. In 2008, EDF decided to deploy a new maintenance methodology, called “AP913”, developed by the American nuclear licensees and built around two main points: organisational changes to enhance monitoring of the reliability of the equipment and systems and implementation of a new type of preventive maintenance programmes. The AP913 implementation diagnostic performed by EDF in mid-2016 revealed difficulties with implementing performance monitoring and with the increase in the maintenance tasks generated by the AP913 maintenance programmes. In 2017, EDF thus defined strategic guidelines for maintenance and reliability. It specified the roles of the various departments and professions related to the performance of maintenance, by reaffirming that the maintenance departments are responsible for the project ownership of the equipment they maintain, in particular in a context of continued operation of the reactors beyond 40 years. EDF also adopted function reviews to obtain an integrated view of the equipment and systems participating in each function, as well as a new phase of its project to control the volume of maintenance. THE INDEPENDENT SAFETY ORGANISATION At EDF, the FIS verifies the actions and decisions taken by the departments in charge of operating the installations, from the viewpoint of safety. On each NPP, the FIS comprises safety engineers and auditors, who conduct a daily check on the safety of the reactors. The working of each FIS is checked and evaluated at a national level by the FIS of EDF’s Nuclear Production Division. Finally, the EDF internal inspectorate, in particular the general inspector reporting to the Chairman of the EDF group, assisted by a team of inspectors, represents the highest level of independent verification of nuclear safety within the EDF group. 296 ASN Report on the state of nuclear safety and radiation protection in France in 2022 • 10 • The EDF Nuclear Power Plants 10
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