Abstracts ASN Report 2019

manufacturing method, which could, when combined with thermal ageing, increase the risk of fast fracture. ĻĴņ ĶĴŅŅļĸķ łňŇ ĸŋŇĸŁņļʼnĸ ŊłŅľ Ňł ĿĸĴŅŁ ŀłŅĸ ĴĵłňŇ ŇĻĸņĸ materials, their ageing kinetics and to assess the fast fracture margins. Ļĸ ķłņņļĸŅ ŃŅłķňĶĸķ ĵŌ ŊĴņ ĸŋĴŀļŁĸķ ĵŌ ŊļŇĻ ŃŅłķňĶŇļłŁ łĹ ĴŁ łŃļŁļłŁ ĹŅłŀ ŇĻĸ łŁ Ӆӆׇ ĴŌ ӅӃӄӌє łĿĿłŊļŁĺ ŇĻļņ ĴŁĴĿŌņļņё ņĸŁŇ ŅĸńňĸņŇņ ĹłŅ ĴķķļŇļłŁĴĿ substantiation of the predicted behaviour of the aged material, identification of the flaws present in the cast elbow assemblies, analysis of the fast fracture margins of the elbow assemblies and in-service monitoring of these components. The substantiating data requests should be presented to ASN during the course of 2020. • «ƺǕɖǼƏɎȒȸɵ ȸƺǔƺȸƺȇƬƺ ǔǣǼƺɀ The licensee is required to keep and update the regulatory reference files required by the above-mentioned Order of ӄӃׇ łʼnĸŀĵĸŅ ӄӌӌӌׇŊļŇĻ ŅĸĺĴŅķ Ňł ĴŁķ ŀłŁļŇłŅļŁĺє These files consist of design, manufacture, overpressure protection files, materials files, in-service observations and, as applicable, deviations processing files. The licensee is required to update these files as often as necessary and at periodic requalification of the main primary and secondary systems. Owing Ňł ŇĻĸ ņŇĴŁķĴŅķļņĸķ ŁĴŇňŅĸ łĹ ŇĻĸ ŅĸŁĶĻ ŅĸĴĶŇłŅņё ĶĴŁ ŃĸŅĹłŅŀ Ĵ ĺĸŁĸŅļĶ ňŃķĴŇĸ łĹ ŇĻĸņĸ ĹļĿĸņє łŅ ŇĻĸ ĹłňŅŇĻ ŃĸŅļłķļĶ ņĴĹĸŇŌ ŅĸʼnļĸŊņ łĹ ŇĻĸ ӌӃӃׇ ĸ ŅĸĴĶŇłŅņё ĶĴŅŅļĸķ łňŇ ŇĻļņ update, which is particular in that the design hypotheses were ļŁļŇļĴĿĿŌ ŃŅłķňĶĸķ ĹłŅ ӇӃׇŌĸĴŅņ łĹ łŃĸŅĴŇļłŁє ŇĻňņ ĸŋĴŀļŁĸķ ŇĻĸ ĻŌŃłŇĻĸņĸņ ĴŁķ ŀĸŇĻłķņ ňņĸķ ĵŌ for updating the equipment files. The entire analysis was the ņňĵĽĸĶŇ łĹ ĴŁ łŃļŁļłŁ ĹŅłŀ ŇĻĸ łŁ Ӌׇ ĶŇłĵĸŅ ӅӃӄӌє also examined all the monitoring programmes planned for the ŀĴļŁ ŃŅļŀĴŅŌ ĴŁķ ņĸĶłŁķĴŅŌ ņŌņŇĸŀņє łĿĿłŊļŁĺ ŇĻļņ ĸŋĴŀļŁĴŇļłŁё ĶłŁņļķĸŅĸķ ŇĻĴŇ ŇĻĸ łʼnĸŅĴĿĿ ĴŃŃŅłĴĶĻ ĴķłŃŇĸķ ĵŌ ļņ satisfactory, while nonetheless asking it to reinforce certain examinations. • …ȵƺȸƏɎǣȒȇ Ȓǔ ȵȸƺɀɀɖȸƺ ƺȷɖǣȵȅƺȇɎ ASN considers that the situation of the second containment is a ŃłļŁŇ ŅĸńňļŅļŁĺ ĶłŁŇļŁňĸķ ʼnļĺļĿĴŁĶĸ ļŁ ӅӃӄӌё ŇĻĸ ŌĸĴŅ ĻĴʼnļŁĺ ĵĸĸŁ marked by the detection of significant levels of fouling in certain SGs on some reactors, liable to impair their operating safety. This finding revealed the inability of maintenance to guarantee a satisfactory level of cleanness. In addition to this assessment, ASN notes that the SG replacement łŃĸŅĴŇļłŁņ ĹłŅ ŅĸĴĶŇłŅņ ӈׇĴŁķ ӉׇłĹ ŇĻĸ ŅĴʼnĸĿļŁĸņ ĴŁķ ŅĸĴĶŇłŅņׇӄ ĴŁķ ӅׇłĹ ŇĻĸ ĿĴŀĴŁʼnļĿĿĸ ĻĴķ Ňł ĵĸ ŃłņŇŃłŁĸķ owing to the numerous deviations affecting the manufacture of these equipment items and led to operations to secure the tubes that were cracked. The in-service monitoring of the other equipment of the MPS, ŃňŅņňĴŁŇ Ňł ŇĻĸ ŅķĸŅ łĹ ӄӃׇ łʼnĸŀĵĸŅ ӄӌӌӌё ŊłňĿķ ĴŃŃĸĴŅ Ňł be appropriate. The detection of a crack on a vessel bottom ŃĸŁĸŇŅĴŇļłŁ łĹ ĴŇŇĸŁłŀ ŅĸĴĶŇłŅ ӆׇļŁ ӅӃӄӊё ŇĻĸ ĶŅĴĶľļŁĺ łĹ ŇŊł ŃĿňĺņ ļŁ ŇĻĸ ņ łĹ ĴĿňĸĿ ŅĸĴĶŇłŅ ӄׇļŁ ӅӃӄӉׇĴŁķ ŇĻĸ ŃĸŅĹłŅĴŇļłŁ łĹ ŇĻĸ Ňňĵĸņ łŁ ŇĻĸ ӅׇŅĸĴĶŇłŅņ łĹ ŇĻĸ ĸĿĿĸʼnļĿĿĸ ĴŁķ ĿĴŀĴŁʼnļĿĿĸ ņ ļŁ ӅӃӄӌׇļĿĿňņŇŅĴŇĸ ŇĻĸ Ņļņľ łĹ ĹňŅŇĻĸŅ ķĴŀĴĺĸ associated with the ageing of the installations. This confirms the need to adapt the level of in-service monitoring accordingly and to bring forward the development of repair processes. The bottom ĻĸĴķ ŃĸŁĸŇŅĴŇļłŁ łĹ ĴŇŇĸŁłŀ ŅĸĴĶŇłŅ ӆׇŊĴņ ŅĸŃĴļŅĸķ ļŁ ӅӃӄӌє א ِ ב Áǝƺ ƬȒȇɎƏǣȇȅƺȇɎɀ א ِ ב ِ׏ xȒȇǣɎȒȸǣȇǕ Ɏǝƺ ƬȒȇɎƏǣȇȅƺȇɎɀ The containments are monitored and tested to check their compliance with the safety requirements. More specifically, their mechanical behaviour must guarantee good tightness of the reactor building if the pressure inside it were to exceed atmospheric pressure, which can happen in certain types of accidents. This is why, at the end of construction and then during the ten-yearly inspections, these tests include an inner containment pressure rise with leak rate measurement. These ŇĸņŇņ ĴŅĸ ŅĸńňļŅĸķ ĵŌ ŇĻĸ ŅķĸŅ łĹ ӊׇ ĸĵŅňĴŅŌ ӅӃӄӅё ņĸŇŇļŁĺ ŇĻĸ general rules concerning Basic Nuclear Installations (BNIs). א ِ ב ِ א ɀɀƺɀɀȅƺȇɎ Ȓǔ Ɏǝƺ ƬȒȇƳǣɎǣȒȇ Ȓǔ Ɏǝƺ ƬȒȇɎƏǣȇȅƺȇɎɀ • …ɮƺȸƏǼǼ ȅƏȇƏǕƺȅƺȇɎ Ȓǔ Ɏǝƺ ƬȒȇɎƏǣȇȅƺȇɎ ǔɖȇƬɎǣȒȇ Ļĸ łŅĺĴŁļņĴŇļłŁ ŃňŇ ļŁŇł ŃĿĴĶĸ ĵŌ ĹłŅ ŀłŁļŇłŅļŁĺ ŇĻĸ activities and systems liable to have an impact on the static and dynamic containment of the facilities is on the whole satisfactory, even if not completely formalised. Locally, this results in deviations affecting certain items, which are not dealt with in good time, the consequence of which is to weaken the static or dynamic containment of the facilities. ļŁĶĸ ӅӃӄӉё ĻĴņ ļŀŃĿĸŀĸŁŇĸķ ĴŁ ĴĶŇļłŁ ŃĿĴŁё ŇĻĸ ŀĴļŁ aim of which is to check that the flow rates of the ventilation systems meet the safety requirements both for containment and for thermal conditioning of the facilities. This action plan will continue until 2025. It will enable an inventory to be drawn up of all the ventilation systems of the reactors. It makes provision for repair when necessary, plus improvements. In the coming years, ASN will therefore be vigilant with regard to the organisational ĴŁķ łŃĸŅĴŇļłŁĴĿ ŀĸĴŁņ ļŀŃĿĸŀĸŁŇĸķ ĵŌ Ňł ĸŁņňŅĸ ŇĻĴŇ compliance with the adjustments made and the good condition of the ventilation equipment concerned are maintained durably. Improvements are also required with regard to the condition of certain components taking part in containment, such as the floor drains. During its inspections, ASN will be vigilant with regard Ňł ѡņ ŀĴļŁŇĸŁĴŁĶĸ łĹ ŇĻĸņĸ ĶłŀŃłŁĸŁŇņє • ³ǣȇǕǼƺ ɯƏǼǼ ƬȒȇɎƏǣȇȅƺȇɎɀ ɯǣɎǝ Əȇ ǣȇɎƺȸȇƏǼ ȅƺɎƏǼ ɀƺƏǼǣȇǕ Ǽǣȇƺȸ Ļĸ ŇĸŁіŌĸĴŅĿŌ ŇĸņŇņ łŁ ŇĻĸ ӌӃӃׇ ĸ ĶłŁŇĴļŁŀĸŁŇņ ĶĴŅŅļĸķ łňŇ ņļŁĶĸ ӅӃӃӌׇĹłŅ ŇĻĸļŅ ŇĻļŅķ ĴŁķ ĹłňŅŇĻ ŇĸŁіŌĸĴŅĿŌ ļŁņŃĸĶŇļłŁņ ķļķ not generally bring to light any particular problems liable to compromise their operation. The containment of Bugey NPP ŅĸĴĶŇłŅ ӈׇķļķ ĻłŊĸʼnĸŅ Łĸĸķ Ňł ĵĸ ŅĸŃĴļŅĸķё ĹłĿĿłŊļŁĺ Ĵ Ŀłņņ łĹ ĿĸĴľŇļĺĻŇŁĸņņ ĹłňŁķ ļŁ ӅӃӄӈׇļŁ ŇĻĸ ĶłŁŇĴļŁŀĸŁŇ ŀĸŇĴĿ ĿļŁĸŅ ŇłŊĴŅķņ ŇĻĸ ĵłŇŇłŀ łĹ ŇĻĸ ŅĸĴĶŇłŅ ĵňļĿķļŁĺє ĴĿņł ļŀŃĿĸŀĸŁŇĸķ specific monitoring. Ļĸ ĴĺĸļŁĺ łĹ ŇĻĸ ӌӃӃׇ ĸ ŅĸĴĶŇłŅ ĶłŁŇĴļŁŀĸŁŇņ ŊĴņ ĸŋĴŀļŁĸķ ĵŌ ŊļŇĻ ŇĻĸ ņňŃŃłŅŇ łĹ ļŁ ӅӃӄӋׇĴŁķ ŊĴņ ŃŅĸņĸŁŇĸķ Ňł the GPR during a session dedicated to ageing. This examination concluded that the cleanness of the outer part of the containments needed to be improved in order to prevent stagnant water, debris, ŀłņņ ĴŁķ łŇĻĸŅ ʼnĸĺĸŇĴŇļłŁє ĻĴņ ļŁļŇļĴŇĸķ ʼnļņňĴĿ ĶĻĸĶľņ łŁ the containment domes. ASN will carry out inspections to ensure the pertinence of these checks. • (ȒɖƫǼƺ ٮ ɯƏǼǼ ƬȒȇɎƏǣȇȅƺȇɎɀ The tests on the double-wall containments performed during the ĹļŅņŇ ŇĸŁіŌĸĴŅĿŌ ļŁņŃĸĶŇļłŁņ łĹ ŇĻĸ ӄёӆӃӃ ĸ ŅĸĴĶŇłŅņ ķĸŇĸĶŇĸķ Ĵ rise in the leak rate from the inner wall of some of them, under the combined effect of concrete deformation and a loss of pre- stressing of certain tendons that was greater than anticipated at the design stage. 286 ASN Report on the state of nuclear safety and radiation protection in France in 2019 ׏׎ ٲ THE EDF NUCLEAR POWER PLANTS