Abstracts ASN Report 2019

in order to define the decommissioning steps and the waste management routes. This is because incomplete understanding of the initial situations and insufficient characterisation of the waste make it necessary to revise the planned steps and lead to difficulties in packaging the waste, which is counterproductive to decommissioning progress. When the waste is removed, very often to interim storage areas, and the main equipment remotely dismantled using the existing handling means, continuation of the decommissioning work usually necessitates opening the radioactive substance containment barriers in order to remove the last process or research equipment and the pipes using, among other things, more substantial cutting and handling equipment. The latter present risks and can lead to dissemination of radioactive material, a potential source of internal and external contamination for the operators who work at close range and must be protected. This work can moreover be carried out near radiation sources, which increases the risk of external exposure for the workers. א ِ א ِ « א ƺɀƺƏȸƬǝ ȸƺƏƬɎȒȸɀ Eight experimental reactors are in final shutdown status at the ĸŁķ łĹ ӅӃӄӌѓ ĴŃņłķļĸ ҎņłķļňŀіĶłłĿĸķ ĹĴņŇ ŁĸňŇŅłŁ ŅĸĴĶŇłŅҏё Masurca (critical mock-up), Phébus (experimental reactor), Osiris, Orphée (“pool” type reactors), ÉOLE and Minerve (critical mock-ups), Ulysse and ISIS (training reactors). They are all in the decommissioning preparation phase, except for Ulysse, ĹłŅ ŊĻļĶĻ ķĸĶłŀŀļņņļłŁļŁĺ ŊĴņ ĶłŀŃĿĸŇĸķ ļŁ ňĺňņŇ ӅӃӄӌє 4. ŅļŇłŁ ŊĴņ łŁĸ łĹ ŇĻĸ ĹļŅņŇ ʼnĸŅŌ ĶłŀŃĴĶŇ ĴŁķ ʼnĸŅŌ ĹĿĸŋļĵĿĸ ŃłłĿ ŇŌŃĸ ŅĸņĸĴŅĶĻ ŅĸĴĶŇłŅņ ĶĴĿĿĸķ Ѣ ѣ Ҏ ĴŇĸŅļĴĿ ĸņŇ ĸĴĶŇłŅҏє ŅļŇłŁ ҎӉєӈׇ ŇĻҏ ŊĴņׇļŁņŇĴĿĿĸķ in Fontenay-aux-Roses, in 1959. These reactors are characterised by a lower power output (from ӄӃӃׇ ŇĻ Ňł ӊӃׇ ŇĻҏ ŇĻĴŁ ŇĻĸ ŁňĶĿĸĴŅ ŃłŊĸŅ ŅĸĴĶŇłŅņє ĻĸŁ ŇĻĸŌ ŊĸŅĸ ķĸņļĺŁĸķ ĵĴĶľ ļŁ ŇĻĸ ӄӌӉӃņ Ňł ӄӌӋӃņё ŇĻĸ ńňĸņŇļłŁ łĹ their decommissioning was not considered. One of the major decommissioning problems is the loss of memory of the design and operation of the installation. Therefore maintaining skills and the installation characterisation phase to determine its initial state (state of the installation at the start of decommissioning) are of vital importance. At the time of decommissioning, these installations usually present a low radiological source term, as one of the first operations consists in removing the spent fuel during the decommissioning preparation operations. The risks involved in research reactor decommissioning oper- ations evolve rapidly due to the numerous changes in the installation. The nuclear risks gradually give way to conventional industrial risks, such as the risk associated with the simultaneous management of several worksites, or the chemical risk during the clean-out phase. One of the main challenges comes from the production and management of large volumes of VLL waste, which must be stored then disposed of via an appropriate route. There is a considerable amount of decommissioning experience feedback for the research reactors, given the decommissioning of ŁňŀĸŅłňņ ņļŀļĿĴŅ ļŁņŇĴĿĿĴŇļłŁņ ļŁ ŅĴŁĶĸ Ҏ ļĿłųё ļĿłĸŇŇĸё ųĿňņļŁĸё Harmonie, Triton (4) , the Strasbourg University Reactor - RUS) and abroad. Their dismantling timeframes span about ten years. Most of these reactors were demolished with conventional disposal following clean-out. La Hague (Orano Cycle) BNI 33 - Spent fuel reprocessing plant (UP2) BNI 38 - STE2 BNI 47 - ÉLAN IIB La Hague BNI 80 - HAO Saclay (CEA) BNI 18 - Ulysse BNI 40 - Osiris BNI 49 - High-Activity Laboratory (LHA) BNI 101 - Orphée Brennilis (EDF) BNI 162 - EL4-D Chinon (EDF) BNI 94 - Irradiated Materials Facility (AMI) BNI 133 - Chinon A1D BNI 153 - Chinon A2D BNI 161 - Chinon A3D Saint-Laurent-des-Eaux (EDF) BNI 46 - Saint-Laurent-des-Eaux A1 et A2 Fontenay-aux-Roses (CEA) BNI 165 - Process BNI 166 - Support Tricastin (Orano Cycle) BNI 105 - Comurhex Tricastin (Orano Cycle) BNI 93 - Georges Besse Plant Chooz (EDF) BNI 163 - Chooz A Bugey (EDF) BNI 45 - Bugey 1 Creys-Malville (EDF) BNI 91 - Superphénix Marcoule (CEA) BNI 71 - Phénix Cadarache (CEA) BNI 25 - Rapsodie BNI 32 - ATPu BNI 37B ٮ 0ǔˢɖƺȇɎ ÁȸƺƏɎȅƺȇɎ Station (STE) BNI 39 - Masurca BNI 42 - ÉOLE BNI 52 - ATUE BNI 53 - MCMF BNI 54 - LPC BNI 56 - Radioactive waste interim storage area BNI 92 - Phébus BNI 95 - Minerve Grenoble (CEA) BNI 36 - STED BNI 79 - Decay interim storage facility xƏȵ Ȓǔ Ɏǝƺ ǣȇɀɎƏǼǼƏɎǣȒȇɀ ƳƺǔǣȇǣɎǣɮƺǼɵ ɀǝɖɎ ƳȒɯȇ Ȓȸ ǣȇ Ɏǝƺ ȵȸȒƬƺɀɀ Ȓǔ ƳƺƬȒȅȅǣɀɀǣȒȇǣȇǕ Əɀ ƏɎ ב ׏ (ژ ƺƬƺȅƫƺȸ א ׎׏ ח 336 ASN Report on the state of nuclear safety and radiation protection in France in 2019 ׏ ٲ ב DECOMMISSIONING OF BASIC NUCLEAR INSTALLATIONS