UWFDM-1225 Impact of CaO Coating on Breeding Potential of ARIES-RS Li/V Blanket System

A number of studies have proposed several electrically insulating coatings for the vanadium structure to mitigate the magneto-hydrodynamic (MHD) pumping power losses for the self-cooled lithium blanket system. The most practical scenario for power plant designs is to add the coating material to the liquid lithium breeder to help the in-situ self-healing process of the microcracking developed during operation to the microns-thick coatings. To date, the coating research has focused on the MHD resistance, compatibility, adherence, thermodynamic, and interface issues, paying little attention to the nuclear issues. Among many coatings, the U.S. researchers have identified CaO as the leading candidate based on overall but non-nuclear criteria. The emphasis of this assessment relates to the impact of the CaO coating on the tritium breeding ratio (TBR) of ARIES-RS (1), a typical Li/V power plant. Our results indicate up to 10% drop in the overall TBR, depending on the Ca concentration in Li. The nuclear requirements could have an important impact on the choice of coating materials and on the maximum coating concentration in Li. Potential solutions that mitigate the effect of the coating and satisfy the design requirements are discussed.