Environmental advantage of fusion power plants

Assessment of neutron activation in fusion power plants made of candidate materials was performed with the power plant modeled after ARIES-RS. Candidate blanket concepts studied were vanadium alloy structure - lithium coolant, reduced activation ferritic martensitic structure - molten salt coolant, and SiC structure - lead lithium eutectic coolant. Power plant components other than the blankets are those proposed in ARIES-RS plant. Ultimate impurities projected from recent literature were included in the analysis. It was found that most of the power plant components could only be recycled with remote-handling technique. To facilitate hands-on recycling to maximize the environmental advantage of fusion power plants, however, requires further reduction of impurities in component materials, and increase in inboard space to allow for more shielding materials in order to reduce the neutron activation in the toroidal field magnets. Increase of inboard space calls for a larger or higher aspect-ratio tokamak power plant, which in turn defines a modest neutron wall loading for a constant fusion power output.