Compatibility issues for liquid breeders and liquid divertor for fusion reactors

As the liquid fuel breeder material of advanced blanket and the coolant for liquid diverter, liquid metals and molten salts attract attention. This paper explains the compatibility between candidate structural materials and functional materials in these high-temperature melts. There was significant progress in the control of dissolved impurities in high-temperature melts, and thereby the prospect for corrosion control has come into sight. Research results have been obtained in large-scale projects such as the Japan-US science and technology cooperation projects. In addition, corrosion test data based on further small studies have been continuously accumulated. The corrosion mechanisms specific to high temperature melts such as the corrosion-erosion mechanism under molten Pb-Li environment, intermetallic compound forming type corrosion under molten tin environment, and oxidation behavior in fluoride molten salts are also becoming clear. In the future, it is expected that compatibility researches under the conditions closer to the actual environment of fusion reactor liquid blanket (under non-isothermal flow or under high magnetic field) will be performed by integrated test equipment such as the Oroshhi-2 of National Institute for Fusion Science. (A.O.)