Separation of hydrogen isotopes by uranium hydride

As for the processes of occlusion, diffusion and permeation of hydrogen in metals, the isotopic effect has been known, and some of them have been considered as the process applied to isotopic separation. In the formation and decomposition of metal hydrides, similarly the existence of isotopic effect is expected. In this paper, the cascade experiment on H-D separation utilizing the equilibrium dissociation of uranium mixed hydride and the preliminary experiment on non-equilibrium dissociation are reported. The experimental apparatus and the experimental method, and the results are described. The mean separation factor was 1.3. This value agreed with the theoretical value obtained from the dissociation pressure, and is considered as the separation factor originated from the equilibrium dissociation of U(H, D)3 only. It takes 3 to 12 hours to reach perfect equilibrium dissociation state in U(H, D)3 system. In the case of heating to 460 deg C, deuterium dissociated more quickly than hydrogen, and the separation factor was somewhat lower than that in equilibrium dissociation. The time required for the reaction was very short. The isotopic separation of hydrogen utilizing the isotopic effect of dissociation pressure can be carried out at 200 - 450 deg C and below 1 atm, and moving parts such as pumps are not necessary. (Kako, I.)