Abstracts ASN Report 2019

environment. Steps must thus be taken by the licensee to protect the sensitive parts of the facility against explosions. ASN checks these prevention and monitoring measures, paying particular attention to ensuring that the explosion risk is ŇĴľĸŁ ļŁŇł ĴĶĶłňŁŇ ļŁ ѡņ ĵĴņĸĿļŁĸ ņĴĹĸŇŌ ŅĸńňļŅĸŀĸŁŇņ ĴŁķ organisation. ASN also ensures compliance with the “Explosive Atmospheres” (ATEX) regulations to ensure worker protection. • XȇɎƺȸȇƏǼ ǔǼȒȒƳǣȇǕ ȸǣɀǸɀ An internal flood, in other words which comes from within the facility, may lead to failure of equipment necessary for reactor shutdown, fuel cooling and containment of radioactive products. Steps are therefore taken to prevent internal flooding (maintenance of piping carrying water, etc.), or mitigate its consequences (presence of floor drains and water extraction pumps, installation of sills or leaktight doors to prevent the flood from spreading, etc.). These measures are regularly inspected by ASN. ASN remains vigilant with regard to the risks of internal flooding as a result of an earthquake, as well as with regard to the integration of operating experience feedback, in particular the processing of deviations affecting certain internal flooding protection measures. • 0ɴɎƺȸȇƏǼ ǔǼȒȒƳǣȇǕ ȸǣɀǸɀ łĿĿłŊļŁĺ ŇĻĸ ŃĴŅŇļĴĿ ĹĿłłķļŁĺ łĹ ŇĻĸ ĿĴŌĴļņ ļŁ ĸĶĸŀĵĸŅ ӄӌӌӌё ŇĻĸ ĿļĶĸŁņĸĸņё ňŁķĸŅ ŇĻĸ ņňŃĸŅʼnļņļłŁ łĹ ё ŅĸĴņņĸņņĸķ the safety of their facilities in the face of this risk, in conditions that were more severe than before, and made numerous safety improvements, according to a schedule defined according to the Ņļņľņє Ł ĴĶĶłŅķĴŁĶĸ ŊļŇĻ ŇĻĸ ŅĸńňļŅĸŀĸŁŇņё ĶłŀŃĿĸŇĸķ the required work on all its nuclear power reactors in 2014. At the same time, to ensure more exhaustive and more robust integration of the flooding risk, as of the facilities design stage, ŃňĵĿļņĻĸķ ňļķĸ łє ӄӆׇļŁ ӅӃӄӆׇĶłŁĶĸŅŁļŁĺ ŃŅłŇĸĶŇļłŁ ĴĺĴļŁņŇ ĸŋŇĸŅŁĴĿ ĹĿłłķļŁĺє łŅ ŇĻĸ ĸŋļņŇļŁĺ ĹĴĶļĿļŇļĸņё Ĵņľĸķ ļŁ ӅӃӄӇׇŇł ŇĴľĸ ĴĶĶłňŁŇ łĹ ŇĻĸ ŅĸĶłŀŀĸŁķĴŇļłŁņ łĹ ŇĻĸ guide on all its reactors: ҄ ĹłŅ ŇĻĸ ӄёӆӃӃ ĸ ŅĸĴĶŇłŅņё Ĵņľĸķ Ňł ĺļʼnĸ ŃŅļłŅļŇŌ to the third periodic safety review; ҄ ĹłŅ ŇĻĸ łŇĻĸŅ ŅĸĴĶŇłŅņ ļŁ ņĸŅʼnļĶĸё ŊļĿĿ ĺļʼnĸ ŃŅļłŅļŇŌ Ňł ŇĻĸ ŁĸŋŇ ŃĸŅļłķļĶ ņĴĹĸŇŌ ŅĸʼnļĸŊņ ҎĹłňŅŇĻ ŅĸʼnļĸŊņ ĹłŅ ŇĻĸ ӌӃӃ ĸ reactors and second reviews for the 1,450 MWe reactors). łĿĿłŊļŁĺ ŇĻĸ ņŇŅĸņņ ŇĸņŇņ ŃĸŅĹłŅŀĸķ ļŁ ŇĻĸ ŊĴľĸ łĹ ŇĻĸ ňľňņĻļŀĴ ĴļļĶĻļ ĴĶĶļķĸŁŇё ĶłŁņļķĸŅĸķ ŇĻĴŇ ŊļŇĻ regard to flooding protection, the requirements resulting from the complete reassessment carried out following the flooding of ŇĻĸ ĿĴŌĴļņׇ ļŁ ӄӌӌӌ ŊłňĿķ ĵĸ ĴĵĿĸ Ňł ŃŅłʼnļķĸ ŇĻĸ ņ ŊļŇĻ a high level of protection against external flooding. However, ļņņňĸķ ņĸʼnĸŅĴĿ ŅĸņłĿňŇļłŁņ ļŁ ňŁĸ ӅӃӄӅׇĴņľļŁĺ ŇĻĸ ĿļĶĸŁņĸĸņѓ ҄ Ňł ŅĸļŁĹłŅĶĸ ŃŅłŇĸĶŇļłŁ ĴĺĴļŁņŇ ĶĸŅŇĴļŁ ĻĴōĴŅķņё ņňĶĻ Ĵņ intense rainfall and earthquake-induced flooding; ҄ to define and implement a “hardened safety core” of material and organisational measures to control the fundamental safety functions in extreme situations and in particular in the case of flooding beyond the design-basis safety requirements (see ŃłļŁŇ Ӆєӌҏє • ³ƺǣɀȅǣƬ ȸǣɀǸɀ ĿŇĻłňĺĻ ņĸļņŀļĶ ĴĶŇļʼnļŇŌ ļŁ ŅĴŁĶĸ ļņ ŀłķĸŅĴŇĸ łŅ ņĿļĺĻŇё ѡņ inclusion of this risk in the safety case for its nuclear power reactors is the subject of constant attention on the part of ASN, given the potential consequences for the safety of the facilities. Seismic protection measures are designed into the facilities. They are periodically reviewed in the light of changing knowledge and changes to the regulations, on the occasion of the periodic safety reviews. ĴņļĶ ĴĹĸŇŌ ňĿĸ Ҏ ҏ ӅӃӃӄіӃӄׇłĹ ӆӄׇ ĴŌ ӅӃӃӄׇķĸĹļŁĸņ ŇĻĸ methodology used to determine the seismic risk for surface BNIs (except for radioactive waste long-term disposal facilities). Ļļņ ļņ ņňŃŃĿĸŀĸŁŇĸķ ĵŌ ňļķĸ ӅѼӃӄׇłĹ ĴŌ ӅӃӃӉׇŊĻļĶĻ defines acceptable calculation methods for a study of the seismic behaviour of nuclear buildings and particular structures such as embankments, tunnels and underground pipes, supports or tanks. The design of the buildings and the equipment important for safety in the NPPs must thus enable them to withstand earthquakes of an intensity greater than the strongest earthquakes that have occurred ļŁ ŇĻĸ ŅĸĺļłŁє ѡņ ņ ĴŅĸ ŇĻňņ ķĸņļĺŁĸķ ĹłŅ ņĸļņŀļĶ ĿĸʼnĸĿņ incorporating the local geological features specific to each one. As part of the periodic safety reviews, the seismic reassessment consists in verifying the adequacy of the seismic design of the facility, taking account of changing knowledge about seismic activity in the region of the site or about the methods for assessing the seismic behaviour of elements of the facility. The lessons learned from international experience feedback are also analysed and integrated into this framework. ĻĴŁĺļŁĺ ľŁłŊĿĸķĺĸ ĿĸĴķņ Ňł ŅĸĴņņĸņņ ŇĻĸ ņĸļņŀļĶ ĻĴōĴŅķ during the periodic safety reviews. łĿĿłŊļŁĺ ŇĻĸ ňľňņĻļŀĴ ĴļļĶĻļ ĴĶĶļķĸŁŇё Ĵņľĸķ to define and implement a “hardened safety core” of material and organisational measures to control the fundamental safety ĹňŁĶŇļłŁņ ļŁ ĸŋŇŅĸŀĸ ņļŇňĴŇļłŁņ ĶłŀŃĴŅĴĵĿĸё ļŁ ŇĻĸ ŅĸŁĶĻ ĶłŁŇĸŋŇё ŊļŇĻ ŇĻĴŇ ŊĻļĶĻ łĶĶňŅŅĸķ ļŁ ĴŃĴŁ łŁ ӄӄׇ ĴŅĶĻ ӅӃӄӄє This “hardened safety core” shall notably be designed to withstand an earthquake of an exceptional level, exceeding those adopted in the design or periodic safety review of the installations. In order to define this exceptional level earthquake, ASN asked Ňł ņňŃŃĿĸŀĸŁŇ ŇĻĸ ķĸŇĸŅŀļŁļņŇļĶ ĴŃŃŅłĴĶĻ Ňł ķĸĹļŁļŁĺ ŇĻĸ ņĸļņŀļĶ ĻĴōĴŅķ ŊļŇĻ Ĵ ŃŅłĵĴĵļĿļņŇļĶ ĴŃŃŅłĴĶĻё ŊĻļĶĻ ŊłňĿķ ĵĸ more closely in line with international best practices. • RƺƏɎɯƏɮƺ ƏȇƳ ƳȸȒɖǕǝɎ ȸǣɀǸɀ During the heat waves in recent decades, some of the watercourses used to cool NPPs experienced a reduction in their flow rate and significant warming. Significant temperature rises were also observed in certain NPP premises housing heat-sensitive equipment. Ňłłľ ĴĶĶłňŁŇ łĹ ŇĻļņ ĸŋŃĸŅļĸŁĶĸ ĹĸĸķĵĴĶľ ĴŁķ ļŁļŇļĴŇĸķ reassessments of the operation of its facilities in air and water ³z ǣȇɀȵƺƬɎǣȒȇ ƏɎ Ɏǝƺ ǼƏɵƏǣɀ z¨¨ ٫ Áɖȸƫǣȇƺ ɖȇƳƺȸǕȒǣȇǕ maintenance 290 ASN Report on the state of nuclear safety and radiation protection in France in 2019 ׏׎ ٲ THE EDF NUCLEAR POWER PLANTS