Phase I of this project is performing research to develop a low activation blanket that uses silicon carbide (SiC) composite material as the structure, liquid lead-lithium (Pb-Li) alloy as the coolant, and tritium breeding material for application to a deuterium-tritium fueled tokamak fusion power reactor. The viable blanket configuration and relevant operational parameters of this innovative blanket are determined from the following aspects: tritium breeding, nuclear heating, radiation shielding to superconducting magnets, magnetohydrodynamic effects, and materials compatibility. Mechanical and thermal hydraulic design viewpoints are also being considered. The radioactive material inventory, afterheat and relevant shutdown dose rate, and near-surface waste disposal rating issues are being investigated. The relationship between the polonium ("O Po) radiological concern and the bismuth content is being quantified to assess the feasibility of the control of bismuth in lead. The compatibility between SiC and Pb-Li alloy is being investigated for several cases by varying the lithium content, for example, between 5 and 17 atomic % lithium in the alloy. Phase I efforts include (1) quantitatively determining the advantages of the low activation SiC/Pb-Li alloy fusion blanket and (2) identifying the developmental needs and experimental procedures to demonstrate the viability of the low activation blanket concept. Phase II efforts are to address the developmental needs and experimental issues associated with development of the low activation blanket.Anticipated Results/Potential Commercial Applications as described by the awardee:Future commercial tokamak power reactors would be significantly benefited by use of low activation fusion blankets developed in this research project. A near-term application of this research is for the International Thermonuclear Engineering Reactor (ITER). The Pb-Li alloy can be used to breed tritium in the base blanket. The low activation blanket can be included as a test blanket module during the engineering phase of the ITER operation. The impurity control process developed to separate bismuth from lead could be extended for the control of other important impurity elements (such as niobium and silver) that are primarily of concern to the waste disposal of fusion power reactors.
