Some technological problems of fusion materials management

Within the framework of the International Energy Agency Program on Environmental, Safety and Economic Aspects of Fusion Power, an international collaborative study on management of fusion radioactive materials has been carried out to examine the back-end of the materials cycle. The strategy for handling fusion activated materials calls for three potential schemes: clearance, recycling and disposal. There is a growing international effort to avoid the underground disposal, for fusion in particular. Plasma facing components (divertor and blanket) normally contain high radioactivity and are not clearable. As clearance of sizeable components (such as biological shield, cryostat, vacuum vessel, and some constituents of magnets) is highly desirable, we identified the source of radioisotopes that hinder the clearance of these components and investigated the impact of impurity control. Another study assessed radioactivity build-up under repeated use of the divertor made of W–La₂O₃ alloy. Effect of impurities on activated materials management is illustrated by the examples of carbon-14 generation and impurities activation in concrete of biological shield. We think that consideration of activated materials management scenarios presented in this paper by example of blanket and divertor replacement is of interest as well.