Abstracts ASN Report 2019

ŅĸŁĶĻ ķĸŇĸŅŅĸŁĶĸ ŃłĿļĶŌё ņňĶĻ Ĵņ ŇĻĸ ĺĴņĸłňņ ķļĹĹňņļłŁ ŃĿĴŁŇņ of the Pierrelatte Defence Basic Nuclear Installation (DBNI) at ŅļĶĴņŇļŁ ĴŁķ ŇĻĸ ӄׇŃĿĴŁŇ łĹ ŇĻĸ ĴŅĶłňĿĸ ļņ ĺłļŁĺ to produce extremely large quantities of very low level (VLL) waste. This massive production of waste in the decades to come, which was not anticipated and which is incompatible with the current capacities of the Cires (1) , was addressed by a PNGMDR working group resulting in several lines of reflection, including the creation of a new centralised repository, the possible recycling of some of the waste or its disposal on site (see chapter 14). ׏ِ א Áǝƺ ³z ƳƺƬȒȅȅǣɀɀǣȒȇǣȇǕ ƳȒƬɎȸǣȇƺ Many factors can influence the choice of one decommissioning strategy rather than another: national regulations, social and economic factors, financing of the operations, availability of waste disposal routes, decommissioning techniques, qualified personnel, personnel present during the operating phase, exposure of the personnel and the public to ionising radiation resulting from the decommissioning operations, etc. Consequently, practices and regulations differ from one country to another. ׏ِ א ِ׏ XȅȅƺƳǣƏɎƺ ƳǣɀȅƏȇɎǼǣȇǕ Decommissioning in the shortest timeframe possible is a core principle in the regulations applicable to BNIs (Order łĹ ӊׇ ĸĵŅňĴŅŌ ӅӃӄӅׇņĸŇŇļŁĺ ŇĻĸ ĺĸŁĸŅĴĿ ŅňĿĸņ ŅĸĿĴŇļʼnĸ Ňł ņҏє It has been included in the doctrine established by ASN for ׇķĸĶłŀŀļņņļłŁļŁĺ ĴŁķ ķĸĿļĶĸŁņļŁĺ ņļŁĶĸ ӅӃӃӌׇĴŁķ ĻĴņ ĵĸĸŁ ŇĴľĸŁ ňŃ ĴŇ ĿĸĺļņĿĴŇļʼnĸ ĿĸʼnĸĿ ļŁ ĶŇ ӅӃӄӈіӌӌӅ łĹ ӄӊׇ ňĺňņŇׇӅӃӄӈ relative to Energy Transition for Green Growth. This strategy moreover avoids placing the technical and financial burden of decommissioning on future generations. It also provides the benefit of retaining the knowledge and skills of the personnel present during operation of the installation, which are vital during the first decommissioning operations. Ļĸ Ĵļŀ łĹ ŇĻĸ ņŇŅĴŇĸĺŌ ĴķłŃŇĸķ ļŁ ŅĴŁĶĸ ļņ ŇĻĴŇѓ Ҋ The licensee prepares the decommissioning of its installation as of the design stage. Ҋ The licensee anticipates decommissioning and sends its decommissioning application file before it stops operating the installation. Ҋ The licensee has financial resources to finance decommission- ing, covering its anticipated expenses by dedicated assets. Ҋ The decommissioning operations are carried out “in as short a time as possible” after shutting down the installation, a timeframe which can vary from a few years to a few decades, depending on the complexity of the installation. ׏ِ א ِ ! א ȒȅȵǼƺɎƺ ƬǼƺƏȇ ٮ ȒɖɎ The decommissioning and post-operational clean-out operations for a nuclear facility must lead to the gradual elimination of ĴŁŌ ĻĴōĴŅķłňņ ņňĵņŇĴŁĶĸņё ļŁ ŃĴŅŇļĶňĿĴŅ ŅĴķļłĴĶŇļʼnĸ ņňĵņŇĴŁĶĸņё resulting from the activation or deposition phenomena, as well as any migration of contamination in the structures of the facility’s premises or the soil of the site. The ASN reference approach, as stated in its doctrine, requires that the licensees deploy decommissioning and clean-out practices taking into account the best scientific and technical knowledge available at the time and in economically acceptable conditions, with the aim of achieving a final state in which all ŇĻĸ ĻĴōĴŅķłňņ ĴŁķ ŅĴķļłĴĶŇļʼnĸ ņňĵņŇĴŁĶĸņ ĻĴʼnĸ ĵĸĸŁ Ņĸŀłʼnĸķ from the BNI. Should it be difficult to apply this approach due to the nature of the contamination, ASN considers that the ӄє ŁķňņŇŅļĴĿ ĶĸŁŇŅĸ ĹłŅ ĺŅłňŃļŁĺё ņŇłŅĴĺĸ ĴŁķ ķļņŃłņĴĿ Ҏ ļŅĸņҏё ĺļʼnĸŁ ŇĻļņ ŁĴŀĸ ļŁ ĶŇłĵĸŅ ӅӃӄӅє ĻĸŁ ĶłŀŀļņņļłŁĸķ ļŁ ӅӃӃӆׇļŇ ŊĴņ ľŁłŊŁ Ĵņ ŇĻĸ ʼnĸŅŌ ĿłŊ level waste disposal facility (CSTFA). 2. ALARA principle (As Low As Reasonably Achievable). licensee must go as far as reasonably possible in the clean-out process. Whatever the case, the licensee must provide technical or economic justification that the reference approach cannot be applied and that the clean-out operations cannot be taken further under acceptable economic conditions using the best technical clean-out and decommissioning methods available. In accordance with the general principles of radiation protection, the dosimetric impact of the site on the workers and public after delicensing must be as low as reasonably possible (ALARA principle) (2) . ASN is not in favour of introducing general thresholds and considers that it is preferable to adopt a case- by-case approach according to the intended subsequent use of the site. More specifically, reaching a threshold with exposure ĿĸĴķļŁĺ Ňł ĴŁ ĸĹĹĸĶŇļʼnĸ ĴŁŁňĴĿ ķłņĸ łĹ ӆӃӃׇի ʼn ҎŀļĶŅłņļĸʼnĸŅŇņҏ ĹłŅ ŇĻĸ ŃňĵĿļĶ ҂ļєĸє łŁĸ ŇĻļŅķ łĹ ŇĻĸ ĴŁŁňĴĿ ķłņĸ ĿļŀļŇ łĹ ӄׇŀ ʼn (millisievert) for the public– is only acceptable after demonstrating the integration of an optimisation process, in accordance with the IAEA texts on the unconditional release of a site contaminated by radioactive substances. In 2016, ASN thus updated and published a guide on structure clean-out operations (Guide No. 14, available on asn.fr ). The provisions of this Guide have already been implemented on numerous installations with diverse characteristics, such as research reactors, laboratories, fuel manufacturing plant, etc. In 2016, ASN also published a guide relative to the management of polluted soils at nuclear installations (Guide No. 24, available on asn.fr ). ׏ِ ב (ƺƬȒȅȅǣɀɀǣȒȇǣȇǕ ȸƺǕɖǼƏɎȒȸɵ ǔȸƏȅƺɯȒȸǸ ŁĶĸ Ĵ ׇļņ ķĸĹļŁļŇļʼnĸĿŌ ņĻňŇ ķłŊŁё ļŇ ŀňņŇ ĵĸ ķĸĶłŀŀļņņļłŁĸķє Its purpose therefore has to change as it is no longer that for which its creation was authorised, as the Creation Authorisation Decree notably specifies the operating conditions of the ļŁņŇĴĿĿĴŇļłŁє ňŅŇĻĸŅŀłŅĸё ŇĻĸ ķĸĶłŀŀļņņļłŁļŁĺ łŃĸŅĴŇļłŁņ ļŀŃĿŌ a change in the risks presented by the installation. Consequently, these operations cannot be carried out within the framework set by the Creation Authorisation Decree. The decommissioning of a nuclear installation is prescribed by a new decree issued on the basis of an opinion from ASN. This decree sets out, among other things, the main decommissioning steps, the decommissioning end date and the final state. As part of its oversight duties, ASN monitors the implementation of the decommissioning operations as directed by the decommissioning decree. In order to avoid fragmentation of the decommissioning projects and improve their overall consistency, the decommissioning file must explicitly describe all the planned operations, from final shutdown to attainment of the targeted final state and, for each step, describe the nature and scale of the risks presented by the facility as well as the envisaged means of managing them. This file is subject to a public inquiry. Given that installation decommissioning operations are often very long, the decommissioning decree can stipulate that some steps will be subject to prior approval by ASN on the basis of specific safety analysis files. The Diagram below describes the corresponding regulatory procedure. The licensee must demonstrate in its decommissioning file that the decommissioning operations will be carried out in as short a timeframe as possible. ASN Report on the state of nuclear safety and radiation protection in France in 2019 333 ׏ ٲ ב DECOMMISSIONING OF BASIC NUCLEAR INSTALLATIONS 13