EDF-UTO (unité technique opérationnelle) has awarded the consortium formed by NUVIA and GDES a new contract for decontamination services during refuelling outages covering all French nuclear power plants for the next eight years. This wide-ranging contract will include site-specific surveys and solutions for the decontamination of areas with a high risk of exposure to radiation (“décontamination lourde”). GDES will be responsible, specifically, for underwater decontamination of the floor and walls of the reactor pool. For this purpose, GDES will complement the decontamination tasks carried out by NUVIA by providing EDF with DEMOS underwater decontamination and LD9 submersible filtration equipment.

DEMOS is the robotic system developed by GDES to clean and decontaminate the floors and walls of pools in the reactor building. It provides on-line visualisation and video recording of operations. The robot reduces contamination levels mechanically through brushing and suction, without using chemicals, thus avoiding the generation of liquid effluents.

DEMOS enables work at a plant to be carried out while the cavity is flooded without interfering with other activities and can be operated in parallel with critical-path activities. Depending on the type of plant, it is even possible to carry out the work before reactor shutdown begins. This technology, already used with excellent results at the Cofrentes and Trillo nuclear power plants in Spain and Laguna Verde in Mexico, minimises dose levels in the cleaning and maintenance tasks that are then performed in the reactor pool, reducing worker dose in mechanical and decontamination tasks by 60%.

The submersible filtration unit, LD-9, filters particles sucked up during decontamination work with DEMOS. The first GDES intervention under this contract is planned for the Cruas nuclear power plant in the first quarter of 2024.