Activation evaluation of fusion solid breeder materials

Solid lithium ceramic compounds are considered prime candidate breeder materials for D-T-based fusion reactors because of the potential advantages in safety, lack of electromagnetic effects, and relative ease of tritium extraction. Li₂O, Li₄SiO₄, LiAlO₂, and Li₂ZrO₃ are among the most plausible candidate solid breeder materials. These materials were studied to compare their activation characteristics after neutron exposure in a fusion reactor, including quantities relevant to safety and waste-disposal. Induced radioactivity, decay heat, biological dose rate, and the waste-disposal rating of these materials were considered. Impurity elements that appear in lithium such as Na, K, and Ca were also included in the analysis. The results show that Li₂ZrO₃ gives the highest values in every aspect of activation concerns except waste disposal, where LiAlO₂ dominates. LiAlO₂ and Li₂ZrO₃ will qualify for 10CFR61 low-level waste disposal only when these materials are located in the lower neutron fluence region in the blanket. Li₂O and Li₄SiO₄ show much lower (at least three orders of magnitude) induced activity than Li₂ZrO₃ and LiAlO ₂ and satisfy all aspects of low activation considerations