Study of treatment as an alternative WM pathway: examples of I-graphite and metallic components such as steam generators - 15212

EDF is working continuously to optimize and secure its waste management pathways, leading in some case to develop appropriate treatment solutions that could be implemented parallel to reference solutions, complementary or as alternative solutions to already existing paths. This approach is illustrated by the examples of steam generators replaced during the operation of French PWR power plants, and of irradiated graphite (stacks and sleeves), coming from the decommissioning of UNGG reactors, which have been shut down. Concerning graphite wastes, the near surface disposal facility intended for this waste does not exist yet, and is currently giving rise to the research of a suitable site, and an evaluation of its performances. While accompanying ANDRA (French national agency for nuclear waste management), in charge of the development of the facility, and while waiting for more data to be available, EDF is continuing the consolidation of graphite wastes radiological inventory, and is working on the development of an alternative management solution, based on a thermal treatment process. Depending on the nature of the treatment, and on the choice of operating parameters, this treatment may contribute to reduce graphite wastes volume and/or promote its acceptance in a disposal facility. Reducing the radiological inventory by decontamination is one of the means to achieve these objectives. Concerning replaced steam generators, nearly 200 of them will have been removed by 2030, and stored on site waiting for their treatment, which represents about 65 000 tons of metal. Initially intended to be cut and packed on NPPs' sites during their dismantling, EDF is studying the economic value of having the steam generators treated in a centralized facility, which allows reducing the volume of final wastes by optimizing cutting operations, while considering recycling after melting. However, this studied pathway implies a number of difficulties to be overcome. In particular, the shipment of such large components to a centralized facility may be complex. Moreover, French regulatory framework does not allow recycling outside nuclear industry, therefore limiting recycling opportunities to storage containers for radioactive wastes. (authors)