A review of ceramic coatings for high temperature uranium melting applications

Abstract Pyrochemical reprocessing is being explored for reprocessing of spent metallic fuels of future fast breeder reactors. This process consists of several operations like electrorefining, cathode processing, and fuel casting process. The cathode processing and fuel pin casting processes are carried out at 1073–1723 K. Hence, the process vessels should withstand high temperatures, molten metals, and molten salts. Several structural materials and coatings have been proposed and evaluated for such applications. However, high density graphite (HDG) is the proposed material for process crucibles due to its high temperature compatibility. Bare HDG cannot be used directly due to reactivity with molten uranium and its alloys. Hence, coatings like yttria over HDG are being proposed to avoid undesirable carbon contamination of uranium. This review provides the various coatings and their performance evaluation for molten metal applications, including our recent works on the development of thermal spray coatings for such an application.