out in the Decommissioning Decree. If the POCO carried out does not allow unconditional release of the site, ASN 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 above). 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(1)). 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). 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. The doctrine implemented by ASN is specified in the guides relative to the structure clean-up operations (Guide No. 14, available at asn.fr), and the management of contaminated 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. 1. ALARA: As Low As Reasonably Achievable. 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 ASN. 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, ASN 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 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 the Decommissioning Decree may stipulate that some steps will, in due course, be subject to prior approval by ASN on the basis of specific safety analysis files drawn up as close as possible in time to the scheduled operations taking into account the best techniques available at the time and in compliance with the objectives set by the Decommissioning Decree (particular as regards the final status and the targeted POCO level). The “Phases in the life of a BNI” Diagram (see previous pages) describes the corresponding regulatory procedure. The decommissioning phase may be preceded by a preparatory stage, provided for in the initial operating licence. This preparatory phase permits for example the removal of a portion of the radioactive and chemical substances, notably the spent fuel in the case of a nuclear reactor, and preparation of the decommissioning operations (readying of premises, preparation of worksites, training of teams, etc.). It is also during this preparatory phase that the installation characterisation operations can be carried out (radiological mapping, analysis of the operating history), which are vital for establishing the targeted POCO scenarios. The Environment Code requires that the safety of a facility undergoing decommissioning be reviewed periodically and at least every 10 years as is the case for all other BNIs. ASN’s objective with these periodic safety reviews is to ascertain that the installation complies with the provisions of its Decommissioning Decree and the associated safety and radiation Known contamination Complete POCO Compatible with all uses Adapted POCO Incompatible with all uses Utilisation restriction Conservation of memory Diagnosis Contamination partially removed Contamination entirely removed Acceptable impact Unacceptable impact Impact assessment Simplified flowchart of ASN’s “contaminated sites and soils” doctrine 356 ASN Report on the state of nuclear safety and radiation protection in France in 2024 Decommissioning of Basic Nuclear Installations
RkJQdWJsaXNoZXIy NjQ0NzU=