Hydrogen absorption properties of U-Th-Zr and U-Th-Ti-Zr alloys

Hydrogen absorption properties of several U-Th-Zr and U-Th-Ti-Zr alloys were investigated for the purpose of developing a new hydride nuclear fuel. Both alloys consisted of two phases, Th and U-Ti-Zr phases for U-Th-Ti-Zr alloys, Th and U-Th-Zr phases for U-Th-Zr alloys. The main phase of hydrogenated alloys were ThZr2H7±x in both systems and hydrogen holding abilities of both alloys were as high as that of Zr. Absorption speed by U-Th-Zr alloys however were much higher than those by U-Th-Ti-Zr alloys. On hydrogenation of U-Th-Ti-Zr alloys the formation of a stable ternary Ti-Zr-H phase disturbed growth of ThZr2H7±x phase, whereas a significant solubility of Th in U-Zr solid solution at high temperatures assisted the growth of ThZr2H7±x phase in the case of U-Th-Zr alloys. (author)