Radiological Issues for the Thin Liquid Walls of ARIES-IFE Study

Heavy ion beam driven inertial fusion energy (IFE) power plants employ liquid wall materials to protect the structure against the energetic x-rays, ions, and debris emitted from the target following each shot. The objective of this assessment is to identify the radiological issues of the candidate liquid wall materials (Pb, LiPb, Sn, and Flibe) using the ARIES-IFE radiation chamber environment. The issues to be addressed include the radioactivity level and liquid waste minimization for waste management. Specifically, the liquids are evaluated with regard to the Class C limitation for waste disposal, a top-level requirement for all ARIES power plant designs. Two extreme cases were analyzed; the worst case is separation of the liquid wall material (highest radiation exposure) and the breeder (lowest radiation exposure), and the best case is the mixing of the two liquid streams. Both tangential and porous wall injection schemes were examined. Pb and LiPb are more radioactive than Sn and Flibe. For the liquid breeder system, the porous wall injection scheme with mixed liquid flows results in the lowest waste disposal rating and smallest waste stream achieved in our study.