ASN 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 may submit one or more appropriate POCO scenarios compatible with the site’s futures usages (confirmed, planned and 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 POCO operations constitute a technical and economic optimum. ASN 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, ASN may make administrative delicensing 1. ALARA principle (As Low As Reasonably Achievable). 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 previous page). In any 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 achievable (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. Phases in the life of a Basic Nuclear Installation At least two years before the planned date, the licensee must inform the Minister responsible for nuclear safety and ASN of its intention to definitively shut down its facility. This notification is made public. The licensee must submit its decommissioning file to the Minister no later than 2 years after shutdown notification. This file sets out the decommissioning operations projected by the licensee and the measures it takes to limit the impacts on people and the environment. 2 years maximum Transmission of decommissioning file Shutdown notification As of the date of final shutdown, the licensee is no longer authorised to operate its facility. The license starts to prepare for the decommissioning of its facility. The decommissioning preparation operations often consist in removing the radioactive and chemical substances present in the facility (spent fuel), reorganising the premises (to create storage areas) or adapting the utility networks (ventilation, electrical power distribution). Final shutdown END OF OPERATION DECOMMISSIONING PREPARATORY PHASE 348 ASN Report on the state of nuclear safety and radiation protection in France in 2023 • 14 • Decommissioning of Basic Nuclear Installations
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