Depleted uranium is produced in the process of nuclear fuel fabrication. The hydriding reaction of depleted uranium with hydrogen was carried out in order to develop the temporary storage medium of tritium gas. The depleted uranium was activated at 450℃ under vacuum conditions. The experimental results showed that the equilibrium pressure was lowered and the composition of uranium hydride was increased with lowering the reaction temperature. The similar tendencies were shown in the experiments using deuterium. The equilibrium pressure of deuterium was slightly higher than that of hydrogen. The uranium metal was converted to the powder after the hydriding reaction.