LES ACTIVITÉS NUCLÉAIRES : RAYONNEMENTS IONISANTS ET RISQUES POUR LA SANTÉ ET L’ENVIRONNEMENT In 2025, 36 nuclear facilities of all types (electricity production or research reactors, laboratories, fuel reprocessing plants, waste processing facilities, etc.) were shut down or undergoing decommissioning in France, corresponding to more than a quarter of the Basic Nuclear Installations (BNIs) in operation. With the exception of the Pressurised Water Reactors (PWRs) in the Nuclear Power Plants (NPPs), whose design follows a generic model, the majority of the BNIs being decommissioned present varied technologies, uses and operating histories, rendering complex the decommissioning operations. The duration of BNI decommissioning operations can thus vary significantly from one facility to another. The French Authority for Nuclear Safety and Radiation Protection (ASNR) notes that if it takes about twenty years to decommission the PWRs, decommissioning may extend well beyond 2050 for some of the “fuel cycle” facilities or old waste storage facilities, as several of them still contain large quantities of waste to be retrieved and conditioned. For these facilities, new equipment and processes have to be developed and built, leading to long and complex decommissioning operations. ASNR thus notes that the schedules established by the licensees in the years 2000 with a view to issuing the first decommissioning decrees are having to be updated to integrate the lessons learned from the first operations and to introduce more realistic operational margins, thereby pushing back the end-of-decommissioning dates much further. ASNR is vigilant regarding the safety risks linked to significant extensions of decommissioning times. Facilities undergoing decommissioning also present particular risks for workers, due to the large number of worksites and the often very specific conditions under which they are executed. ASNR pays particular attention to ensuring that radiation protection principles are properly applied and that appropriate containment measures are put in place on worksites. 1 – Technical and legal framework for decommissioning The term decommissioning covers all the technical and administrative activities carried out after the final shutdown of a nuclear installation, following which it can be delicensed, in other words removed from the list of BNIs. These activities comprise the removal of radioactive materials and waste still present in the facility and operations to dismantle the equipment and components used during operation, as well as clean-out of the premises and soils plus civil engineering structures demolition work as necessary. The aim of the decommissioning and clean-out operations is to achieve a predetermined final state that allows prevention of the risks and impacts that the site may present for the environment and people, taking into account its possible future uses. The decommissioning of a nuclear installation is prescribed by Decree issued after consulting ASNR. This phase in the life cycle of the installations is characterised by a succession of operations which are sometimes highly complex, are lengthy, produce large amounts of waste, and are costly; optimum forward planning is essential – especially given that they must be carried out within the shortest time frame possible, as stipulated in the regulations. The continuous changes that installations undergo in the course of decommissioning alter the nature of the risks and represent challenges for the licensees in terms of project management. 1.1 Decommissioning challenges Accomplishing the decommissioning operations – which are often long and costly – within the set time frames is a challenge for the licensees in terms of project management, skills maintenance and coordination of the various operations which involve numerous specialist companies. Despite this, the principle of immediate dismantling in France obliges the licensees to carry out their decommissioning operations within the shortest time frame possible under economically acceptable conditions (see point 1.2). Decommissioning comprises a series of operations which tend to gradually reduce the quantity of radioactive substances present in the facility, resulting in evolving risk levels. Although the reduction in the quantities of substances present in the facility tends to reduce the risks, the decommissioning work, which sometimes takes place very close to the radioactive substances, nevertheless presents significant radiation exposure risks for the workers. Other risks also increase as the work proceeds, such as the risk of dispersion of radioactive substances into the environment or certain conventional risks, such as risks of falling loads when handling large components, or of fires during hot work in the presence of combustible materials, instability of partially dismantled structures, or chemical risks during decontamination operations. 336 ASNR Report on the state of nuclear safety and radiation protection in France in 2025
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