was not anticipated and which is incompatible with the current capacities of 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 metal waste or on-site disposal solutions. ASN issued a position statement in 2020 on the studies submitted by the licensees on this subject (see chapter 14). 1.2 The ASN decommissioning doctrine At the international scale, 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 and qualified personnel, knowledge of the operating history, 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. 1.2.1 Immediate dismantling The principle of decommissioning “in the shortest time frame possible under economically acceptable conditions” figures in the regulations applicable to BNIs (Order of 7 February 2012 setting the general rules relative to BNIs). This principle, which ASN has affirmed since 2009 as regards BNI decommissioning and delicensing, has been enshrined in legislation by Act 2015‑992 of 17 August 2015 relative to Energy Transition for Green Growth. This approach aims to avoid 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. The aim of the strategy adopted in France is that: ∙ the licensee prepares the decommissioning of its installation as of the design stage; ∙ the licensee anticipates decommissioning and sends ASN the decommissioning application file before it stops operating the installation; ∙ the licensee has financial resources to finance decommissioning, covering its anticipated expenses by dedicated assets; ∙ the decommissioning operations are carried out “in as short a time frame as possible” after shutting down the installation, a time frame which can nevertheless vary from a few years to a few decades. The decommissioning plan, which describes the operations the licensee intends implementing to decommission its facility, aims in particular to prepare and plan ahead for decommissioning as best possible. Since 2007, this document has been required as from commissioning of the facility, and is then updated regularly during its lifetime. It capitalises on the operating experience feedback by identifying any impacts on the future decommissioning operations, and must enable the licensee to justify the chosen decommissioning strategy on the basis of technical and economic criteria. 1.2.2 Cleaning up and achieving the final state The decommissioning and clean-up operations of a nuclear facility must lead to the gradual removal of the radioactive or hazardous substances from the structures and soils, with a view to delicensing the facility with its subsequent withdrawal from the 1. Cires: French acronym standing for "Industrial centre for grouping, storage and disposal". Located in Morvilliers (Aube département) and renamed Cires in October 2012, it was originally commissioned in 2003 under the name CSTFA, standing for "Very-low level waste disposal facility". 2. ALARA – As Low As Reasonably Achievable. list of BNI. The radioactive substances can result from activation or deposition phenomena caused by the activities of the BNI. Hazardous chemical substances can also be present in the facility due to the use of certain processes or products (hydrocarbons, hydrofluoric acid, sodium, etc.). In some cases, the radioactive or hazardous substances migrate into the structures of the BNI buildings, or even into the soils of the site and its surroundings, in which case they must be cleaned out. Clean-up corresponds to the operations to reduce or eliminate radioactivity or any other hazardous substances remaining in the structures or soils alike. ASN asks the licensees to deploy clean-up practices that integrate the best available scientific and technical knowledge under economically acceptable conditions. The complete clean-up scenario must always be envisaged as the reference scenario. This scenario, which leads to unconditional release of the buildings and sites, effectively enables the protection of people and the environment to be guaranteed over time with no reservations. In the event of identified technical, economic or financial difficulties, the licensee can submit one or more appropriate clean-up scenarios compatible with the site's futures usages (confirmed, planned or practicable) to ASN. Whatever the case, the licensee must provide elements proving that the reference scenario cannot be applied under acceptable technical and economic conditions and that the planned clean-up operations constitute a technical and economic optimum. In such cases ASN examines the scenarios proposed by the licensee and ensures that the clean-up will be taken as far as reasonably possible. Whatever the case, ASN considers that the clean-up strategy implemented by the licensee must lead to a final state of the BNI and its site that is compatible with administrative delicensing. 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 achievable (ALARA principle(2)). ASN is not in favour of introducing generalised thresholds and considers it preferable to adopt an optimisation approach, based on technical and economic criteria, according to the future usages of the site (confirmed, planned and practicable). By way of example, the International Atomic Energy Agency (IAEA) recommends, for the unconditional release of a site polluted by radioactive substances, achieving a final state corresponding to a level of exposure leading to an effective annual dose of 10 microsieverts (μSv) –i.e. one hundredth of the annual maximum dose of 1 millisievert (mSv) for the public. It recommends moreover, to have an effective annual dose of less than 300 µSv, the implementation of usage restrictions in application of the principles of radiation protection (limitation, optimisation and justification of the received dose). Whatever the case, once the site has been delicensed, the induced radiological exposure must not exceed the statutory value of 1 mSv over one year for all the usage scenarios. This ASN position specifies its doctrine, which is laid down in the guides relative to the structure clean-up operations (Guide No. 14, available at asn.fr), and the management of polluted soils in nuclear installations (Guide No. 24, available at asn.fr). The provisions of these guides have already been implemented on numerous installations with varied characteristics, such as research reactors, laboratories, fuel manufacturing plants, etc. ASN Report on the state of nuclear safety and radiation protection in France in 2021 329 13 – DECOMMISSIONING OF BASIC NUCLEAR INSTALLATIONS 08 07 13 04 10 06 12 14 03 09 05 11 02 AP 01
RkJQdWJsaXNoZXIy NjQ0NzU=