Long-term radioactive waste from fusion reactors

Avoiding the generation of high-level long-lived radioactive waste has been a major goal of fusion energy research in the US for some time. This paper presents the results of neutron-activation and waste-disposal hazard calculations for 58 elements that could be major, minor, or trace constituents of fusion reactor materials. The calculations are for the first wall of a lithium-cooled blanket exposed to 20 MW-y/m2 14 MeV neutron fluence. The specific activity of all radionuclides with half-lives greater than 5 years is given for each naturally-occurring element. The maximum concentration limits allowed for each element that would permit shallow burial are calculated according to the methodology developed for the current 10CFR61 Federal regulations. Deficiencies in the nuclear data that may significantly alter these results are reviewed. Finally, the possibility of isotopically tailoring certain troublesome elements is discussed