Solid waste products of EU DEMO – Focus on tungsten dust reprocessing

Abstract

The operation of the future EU DEMO, a fusion power plant, will produce various kinds of radioactive waste through neutron activation and contamination with tritium.For the EU DEMO's nuclear fusion reactor, the preliminary construction designs of the main systems and components are known. These designs, as well as the operation of experimental fusion test facilities, are the basis for assessing which materials are likely to become waste. The continuously generated waste materials are solid dusts. They originate in different parts of the fusion reactor, move and usually settle elsewhere. These dusts also appear during intermediate periodic maintenance of a fusion device, most often from the armour surfaces. Another group of similar wastes is generated during the treatment of replaced parts.The waste comprises dust abraded during the overhaul of the equipment, and other small residues. Tungsten dust, which contains tritium, is produced in the largest quantity.An overview of the expected solid waste masses was reviewed, distinguishing what could come from operational process and what could come from decommissioning according to their activation classification levels and with regards to the storage potential capacities. Proposals for processing methods (for in or outside the DEMO site) that allow for reducing and minimizing the solid waste are included. Moreover, the lessons learnt from the ITER experiment are considered.Two methods using high-temperature technologies – induction heating or MSO (Molten Salt Oxidation) technology, are proposed for reprocessing the tungsten dust waste.