preparatory phase permits, for example, the removal of a portion of the radioactive and chemical substances (including the fuel of a nuclear reactor) as well as preparing for 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 mappings, analysis of the operating history), which are vital for establishing the targeted clean-up scenarios. The Environment Code requires –as is the case for all other BNIs– that the safety of a facility undergoing decommissioning be reviewed periodically and at least every 10 years. 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 protection requirements through to its delicensing by applying the principles of defence in depth specific to nuclear safety, with an approach that is proportionate to the risks. This is because, if the decommissioning operations result in a weakening, or even the disappearance of the existing physical barriers, the licensee must, depending on the residual safety and radiation exposure risks, maintain appropriate lines of defence necessary for the protection of workers and the environment (setting up of air locks, nuclear ventilation, radiation monitors, etc.). On completion of decommissioning, a nuclear facility can be delicensed by an ASN resolution approved by the Minister responsible for nuclear safety. It is then removed from the list of BNIs and is no longer subject to the BNI regulatory framework. As part of its delicensing application, the licensee must provide a file containing a description of the state of the site after decommissioning (analysis of the state of the soils, remaining buildings or facilities, etc.) and demonstrating that the planned final state has been reached. Depending on the final state reached, ASN may require the implementation of active institutional controls as a condition of delicensing. These may set a number of restrictions on the use of the site and buildings (use limited to industrial applications for example) or precautionary On the basis of the decommissioning file submitted by the licensee, the Minister issues a decree prescribing the decommissioning operations that will be carried out on the facility, and the duration of decommissioning. ASN may also impose technical requirements through a resolution, in order to regulate the decommissioning operations more closely. Decommissioning concerns all the technical operations carried out with a view to achieving a final state that allows delicensing of the facility. It concerns the electromechanical decommissioning and the clean-out and remediation of structures and soils. Decommissioning decree Decommissioning operations DECOMMISSIONING Delicensing consist in withdrawing a facility from the list of BNIs, which implies that the facility from this point is no longer subject to the BNI legal and administrative system. Delicensing takes place after completion of the decommissioning operations on the basis of a file presenting the final state of the facility. When necessary, usage restrictions may be introduced if it has not been possible to remove all the pollution. DELICENSING Delicensing resolution The duty of ASN stops here DÉCISION DÉCISION DÉCISION DÉCISION DELICENSING D ASN Report on the state of nuclear safety and radiation protection in France in 2021 331 13 – DECOMMISSIONING OF BASIC NUCLEAR INSTALLATIONS 08 07 13 04 10 06 12 14 03 09 05 11 02 AP 01
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