Abstracts ASN Report 2019

ג ِ ב ɀɀƺɀɀȅƺȇɎ Ȓǔ Ɏǝƺ !0 ټ ɀ ƳƺƬȒȅȅǣɀɀǣȒȇǣȇǕ ɀɎȸƏɎƺǕɵ CEA’s decommissioning strategy is presented in the notable events part of this report. Given the number and complexity of the operations to be carried out for all the nuclear facilities concerned, CEA is giving priority to reducing the “Potential Source Term” (TSM (6) ) which is currently at a very high level in certain facilities, in particular ļŁ ņłŀĸ łĹ ŇĻĸ ļŁķļʼnļķňĴĿ ĹĴĶļĿļŇļĸņ łĹ ŇĻĸ ĴŅĶłňĿĸ ׇĴŁķ ļŁ ņ ӊӅׇҎļŁ ĴĶĿĴŌҏ ĴŁķ ӈӉׇҎļŁ ĴķĴŅĴĶĻĸҏє Ł ŇĻĸļŅ łŃļŁļłŁ łĹ Ӆӊׇ ĴŌ ӅӃӄӌё ĴŁķ ŇĻĸ ĶłŁņļķĸŅĸķ that, given the resources allocated by the State and the large number of facilities undergoing decommissioning, for which legacy waste retrieval and storage capacity will need to be built, it was acceptable for CEA to envisage staggering the decommissioning operations and that priority be given to those facilities in which the safety issues were greatest. The authorities underlined the fact that in the light of the calendars presented, risk reduction would not be effective for about another ten years, even in the absence of any unforeseen incidents or delays in the projects. 6. The Potential Source Term (TSM) corresponds to the quantity of radioactive activity that could be involved in an incident or accident. It is defined from the “source term” (activity of all the radioactive substances present in the facility) weighted by factors linked to: - the dispersibility of the matrix (according to whether or not the radioactive substances are blocked in the materials and the nature of the blocking matrix), - the effectiveness of the containment barriers (according to the seismic strength of the building and whether or not the ventilation is available for operation), - the susceptibility of the source term to external hazards (the accident scenario adopted is an earthquake combined with a fire), - the radiotoxicity of the inventory ( у - ф , tritium or т spectrum). With regard to those facilities classified as lower priority, the authorities asked CEA on the one hand to define the safety improvement and environmental protection actions, notably as a result of the periodic safety reviews and, on the other, the principles of monitoring, upkeep and operation chosen to maintain the facilities in a sufficiently safe state, once the TSM has been removed, for a period of decades until such time as they are delicensed. In their opinion, the authorities also drew attention to the fact that the priority given to the decommissioning of the facilities with the greater safety issues will require substantiated requests for modification of the prescribed decommissioning conditions, notably for the facilities of lower priority. 342 ASN Report on the state of nuclear safety and radiation protection in France in 2019 ׏ ٲ ב DECOMMISSIONING OF BASIC NUCLEAR INSTALLATIONS