Overview on the management of radioactive waste from fusion facilities: ITER, demonstration machines and power plants

In the absence of official standards and guidelines for nuclear fusion plants, fusion designers adopted, as much as possible, the well-established standards for fission based Nuclear Power Plants (NPPs). This often implies interpretation and/or extrapolation, due to differences in structures; systems and components; materials; safety mitigation systems; risks; etc. This approach could result in considering overconservative measures that might lead to an increase of cost and complexity with limited or negligible improvements. One important topic is the generation of radioactive waste in fusion power plants. Fusion waste is significantly different from the fission NPP waste, i.e., the quantity of fusion waste is much larger, however it is mostly comprised of Low-Level Waste (LLW) and Intermediate Level waste (ILW). Notably, the waste does not contain many long-lived isotopes, mainly tritium and other activation isotopes but no-transuranic elements. Important benefit of fusion is the lower decay heat removal and rapid radioactivity decay overall. The dominant fusion wastes are primarily composed of structural materials, such as different types of steel, including reduced activation ferritic martensitic (RAFM) steels, like EUROFER97 and F82H; AISI 316L; bainitic; and JK2LB. The relevant long-lived radioisotopes come from alloying elements such as niobium, molybdenum, nickel, carbon, nitrogen, copper, and aluminum and also from uncontrolled impurities (of the same elements, but also e.g., of potassium and cobalt). After irradiation, these isotopes might preclude disposal in LLW repositories. Fusion power should be able to avoid creating High-Level Waste (HLW), but the amount of fusion ILW and LLW will be significant. Thus, the efforts of recycling and clearance are essential to support fusion deployment, reclaim resources (through less ore mining), minimize the radwaste burden for future generations, and continue holding the promise of fusion energy production with low environmental impact.