Abstracts ASN Report 2019

In order to improve the reliability of the equipment important ĹłŅ ņĴĹĸŇŌ ĵňŇ ĴĿņł ļŁķňņŇŅļĴĿ ŃĸŅĹłŅŀĴŁĶĸё ļņ łŃŇļŀļņļŁĺ ļŇņ maintenance activities, drawing on practices used in conventional industry and by the licensees of NPPs in other countries. ļŁĶĸ ӅӃӄӃё ĻĴņ ŇĻňņ ļŁļŇļĴŇĸķ ŇĻĸ ķĸŃĿłŌŀĸŁŇ łĹ Ĵ ŁĸŊ ŀĴļŁŇĸŁĴŁĶĸ ŀĸŇĻłķłĿłĺŌё ĶĴĿĿĸķ іӌӄӆё ķĸʼnĸĿłŃĸķ ĵŌ ŇĻĸ American nuclear licensees. The main interest of this method is to make the equipment more reliable through in-service monitoring, in order to improve preventive maintenance. Deployment of this maintenance methodology is based on implementation of the following six processes: Ҋ identification of critical equipment and definition of the associated maintenance and monitoring programmes; Ҋ definition of equipment monitoring and maintenance requirements; Ҋ equipment and systems performance analysis; Ҋ definition and oversight of corrective measures; Ҋ continuous improvement of baseline requirements and oversight of reliability; Ҋ equipment lifecycle management. ĹŇĸŅ ĴŁ іӌӄӆׇķĸŃĿłŌŀĸŁŇ ŅĸʼnļĸŊ ļŁ ӅӃӄӉё ķĸʼnĸĿłŃĸķ its practices in order to guarantee the quality of maintenance work, refocus performance monitoring on the most important equipment and systems and optimise the volume of maintenance operations. א ِ ג ِ ג ɀɀƺɀɀȅƺȇɎ Ȓǔ ȅƏǣȇɎƺȇƏȇƬƺ Most of the NPPs are satisfactorily organised to successfully carry out the large-scale maintenance operations currently being performed. However, ASN regularly notes points to be improved concerning ŅĸĴĶŇłŅ ŀĴļŁŇĸŁĴŁĶĸє ĸņŃļŇĸ ѡņ ļŀŃĿĸŀĸŁŇĴŇļłŁ łĹ ĴŁ ĴĶŇļłŁ plan to reduce their occurrence, maintenance quality defects causing significant safety events persist at a level that is still too high, even though some of them could have been avoided by greater preparation of the activities in advance. Activity management faults are sometimes caused by problems in procuring and installing spare parts. Spare parts are regularly unavailable, or non-conforming, or their storage conditions are ļŁĴķĸńňĴŇĸє ŁĶłŅŅĸĶŇĿŌ ĴŃŃĿļĸķ ŁĴŇļłŁĴĿ ķłĶňŀĸŁŇņ łŅ incorrect operational documents are the cause of inappropriate maintenance or maintenance quality defects. Poor performance of the work is too often detected belatedly, in other words only during the operations to requalify the equipment after the maintenance work. ASN also observed that the requalification ŇĸņŇņ ĴŅĸ ŁłŇ ĴĿŊĴŌņ ĴĵĿĸ Ňł ķĸŇĸĶŇ ĸńňļŃŀĸŁŇ ķĸĹĸĶŇņє ļŁĴĿĿŌё taking corrective measures to deal with maintenance-related deviations is sometime ineffective or only temporary. ASN sees an improvement in the technical oversight of the work and contractor monitoring, particularly through the use of computer tools recently deployed in the NPPs. Ł ӅӃӄӌё Ĵņľĸķ ĹłŅ Ĵ ŅĸʼnļĸŊ łĹ ļŇņ ŀĴļŁŇĸŁĴŁĶĸ ŃłĿļĶŌё ļŁ ŃĴŅŇļĶňĿĴŅ ŊļŇĻ ŅĸĺĴŅķ Ňł ŇĻĸ іӌӄӆׇŀĴļŁŇĸŁĴŁĶĸ ŀĸŇĻłķ Ҏņĸĸ point 2.4.3) and the adaptations which have been implemented. Ł ӅӃӅӃё ŊļĿĿ ĸŋĴŀļŁĸ ѡņ ĴŁņŊĸŅņ ŊļŇĻ ŅĸņŃĸĶŇ Ňł ŇĻĸ inadequacies it has identified on this subject. In the context of the continued operation of the reactors, the “major overhaul” programme and the lessons learned from the ĴĶĶļķĸŁŇ ĴŇ ŇĻĸ ňľňņĻļŀĴ ĴļļĶĻļ ё ĶłŁņļķĸŅņ ŇĻĴŇ ļŇ ļņ ļŀŃłŅŇĴŁŇ ĹłŅ Ňł ĶłŁŇļŁňĸ ŊļŇĻ ŇĻĸ ĸĹĹłŅŇņ ļŇ ĻĴņ ĴĿŅĸĴķŌ begun in order to remedy the difficulties encountered and improve the quality of its maintenance activities. א ِ ג ِ ד ¨ȸƺɮƺȇɎǣȇǕ Ɏǝƺ ƺǔǔƺƬɎɀ Ȓǔ ǣȇɎƺȸȇƏǼ ƏȇƳ ƺɴɎƺȸȇƏǼ ǝƏɿƏȸƳɀ • Iǣȸƺ ȸǣɀǸɀ In the same way as the other BNIs, NPPs are subject to ASN ŅĸņłĿňŇļłŁ ӅӃӄӇі іӃӇӄӊׇłĹ ӅӋׇ ĴŁňĴŅŌ ӅӃӄӇё ŅĸĿĴŇļŁĺ Ňł ŇĻĸ ŅňĿĸņ applicable to BNIs for controlling fire risks. The way the fire risk is taken into account in the NPPs is based on the principle of defence in depth built around three levels, that is the design of the facilities, fire prevention and firefighting. Design rules must prevent a fire from spreading and mitigate its consequences; they are based primarily on “fire sectorisation”. This involves dividing the facility into sectors and containment areas designed to keep the fire within a given perimeter bounded by items (doors, walls and fire dampers) offering a specified fire resistance duration. The main purpose is to prevent a fire spreading to two redundant equipment items performing a fundamental safety function. Prevention primarily consists in: ҄ ensuring that the nature and quantity of combustible material in the premises remains below the hypotheses adopted for fire sectorisation; ҄ identifying and analysing the fire risks in order to take steps such as to avoid them. More specifically, for all the work liable to generate a fire, a “fire permit” must be issued and protective measures taken. ļŁĴĿĿŌё ŇĻĸ ķĸŇĸĶŇļłŁ łĹ ĴŁ łňŇĵŅĸĴľ łĹ ĹļŅĸ ĴŁķ ĹļŅĸіĹļĺĻŇļŁĺ should enable a fire to be brought under control and then extinguished within a time compatible with the fire resistance duration of the sectorisation elements. ASN checks that the fire risk is taken into account in the NPPs, notably through an analysis of the licensee’s baseline safety standards, monitoring of significant events reported by the licensee and inspections performed on the sites. The important risks associated with fire have been the subject łĹ ŁňŀĸŅłňņ ŅĸńňĸņŇņ ņļŁĶĸ ӅӃӃӆׇĴŁķ ŇĻňņ ŅĸŀļŁķĸķ ļŁ ӅӃӄӉׇŇĻĴŇё ĹłŅ ŇĻĸ ŃňŅŃłņĸņ łĹ ŇĻĸ ĹłňŅŇĻ ŃĸŅļłķļĶ ņĴĹĸŇŌ ŅĸʼnļĸŊ łĹ ŇĻĸ ӌӃӃׇ ĸ ŅĸĴĶŇłŅņё ļŇ ĸŋŃĸĶŇĸķ Ĵ ŊĸĿĿіņŇŅňĶŇňŅĸķ and robust safety case based on a defence in depth approach. ļņ ĸŋĴŀļŁļŁĺ ŇĻĸ ĽňņŇļĹļĶĴŇļłŁ ŀĸŇĻłķņ ŃŅłķňĶĸķ ĵŌ є Ļĸņĸ ŊĸŅĸ ņňĵŀļŇŇĸķ Ňł ŇĻĸ ĹłŅ ĴŁĴĿŌņļņ ļŁ ӅӃӄӌє • 0ɴȵǼȒɀǣȒȇ ȸǣɀǸɀ An explosion can damage the items essential for maintaining safety or lead to rupture of the containment and the dispersal of radioactive materials into the facility, or even into the Áǝƺ XȇƳƺȵƺȇƳƺȇɎ ³ƏǔƺɎɵ ÁƺƏȅ ٢IX³٣ 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 Nuclear Power Plant (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. ASN Report on the state of nuclear safety and radiation protection in France in 2019 289 ׏׎ ٲ THE EDF NUCLEAR POWER PLANTS 10