An Investigation of the Radioactive Waste Generated in a Future Fusion Reactor

Fusion devices offer the great advantage that the main source of radioactivity is generated from the activation of the plasma surrounding components. This process is dependent on the careful selection of the irradiated materials, alloying elements and impurities, which could effectively influence the radioactive inventory in any fusion device. It is crucial to limit the volume of materials that ultimately become classified as radioactive, long-lived waste, requiring long-term storage or disposal in a deep geological repository, in order to reduce the burden on future generations and to maintain a positive perception of fusion in competition with other energy sources. Tungsten and its alloys are currently considered as prime candidates for plasma facing components in many fusion experimental devices and power plants, but some issues regarding the environmental impact of these materials remain to be clarified. This study addresses the activation of seven candidate structural W alloys that could be used for W-based divertors, under the operating conditions of the international ITER experimental facility, the US ARIES-ACT power plant, and the EU PPCS power plant, assessing the waste management options and the sensitivity of W transmutation to soft and hard neutron spectra of several divertor and blanket concepts.