LES ACTIVITÉS NUCLÉAIRES : RAYONNEMENTS IONISANTS ET RISQUES POUR LA SANTÉ ET L’ENVIRONNEMENT In some cases, the radioactive or hazardous substances migrate into the structures of the installation buildings, or even into the soils of the site and its surroundings, in which case they must be cleaned out. POCO corresponds to the operations to reduce or eliminate radioactivity or any other hazardous substances remaining in the structures or soils alike. ASNR asks the licensees of nuclear facilities to implement POCO practices that integrate the best available methods and techniques under economically acceptable conditions. The complete POCO 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 POCO scenarios compatible with the site’s futures usages (confirmed, planned and practicable) to ASNR. 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 POCO operations constitute a technical and economic optimum. ASNR then examines the scenarios proposed by the licensee and ensures that the POCO will be taken as far as reasonably possible in order to meet the objectives set out in the Decommissioning Decree. If the POCO carried out does not allow unconditional release of the site, ASNR may make administrative delicensing of the facility conditional upon the implementation of active institutional controls, limiting the right of ownership and use of the soil, instituted by the public authority at the request of the licensee (see flowchart below). Whatever the case, the regulations stipulate that the POCO strategy implemented by the licensee must lead to a final state of the BNI and its site that is compatible with administrative delicensing (see point 1.3). 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)). ASNR 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). Nevertheless, whatever the case, once the site has been delicensed, the induced radiological exposure must not exceed the statutory value prescribed in the Public Health Code of 1 millisievert (mSv) over one year for all the usage scenarios. 2. ALARA: As Low As Reasonably Achievable. The doctrine implemented by ASNR is specified in the guides relative to the structure clean-up operations (Guide No. 14, available at asnr.fr), and the management of contaminated soils in nuclear installations (Guide No. 24, available at asnr.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. 1.3 Decommissioning regulatory framework Once a BNI is definitively shut down, it must be decommissioned. Its purpose therefore has to change with respect to that for which its creation was authorised, as the Creation Authorisation Decree (DAC) specifies the operating conditions of the installation. Furthermore, the decommissioning operations imply a change in the risks presented by the installation. Consequently, these operations cannot be carried out within the framework set by the DAC. The decommissioning of a nuclear installation is prescribed by a new decree issued on the basis of an opinion from ASNR. Among other things, this decree sets out the main decommissioning steps, the planned decommissioning end date and the final state to be achieved. As part of its oversight duties, ASNR monitors the implementation of the decommissioning operations as directed by the Decommissioning Decree. In order to avoid fragmentation of the decommissioning projects and to 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 means of managing them. The licensee must demonstrate in its decommissioning file that the decommissioning operations will be carried out in as short a time frame as possible. This file undergoes a public inquiry during which the local residents, local authorities and Local Information Committee (CLI) are called upon to respond. Furthermore, the decommissioning files representing the most significant risks are examined by the Advisory Committee of Experts for Decommissioning (GPDEM), set up in 2018. The facility decommissioning operations are often very long and are not always known in detail when constituting the decommissioning file. This is why ASNR may stipulate, in an individual resolution governing decommissioning, that some steps will, in due course, be subject to prior approval by ASNR, on the basis of specific safety files drawn up as close as possible in time to the scheduled operations, taking into Known contamination Complete POCO Compatible with all uses Adapted POCO Incompatible with all uses Utilisation restriction Diagnosis Contamination partially removed Contamination entirely removed Acceptable impact Unacceptable impact Impact assessment Simplified flowchart of ASNR’s “contaminated sites and soils” doctrine CONSERVATION OF MEMORY 338 ASNR Report on the state of nuclear safety and radiation protection in France in 2025
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