Reaction of Hydrogen with Uranium

Abstract

The reaction of hydrogen with uranium to produce uranium hydride was studied in the temperature range 96°–400°C at pressure levels of of mercury (where is system pressure and is the plateau dissociation pressure of the uranium hydride product). Reaction rates followed the linear law. At a given , the linear rate increased with increasing temperature in the range 96° to about 250°C and decreased with increasing temperature from about 250° to 400°C. Variation of the linear rate with temperature and pressure in the range 96° to about 250°C is given by the equation: where is in units of ml/cm2/sec and is in units of mm Hg. In the range from about 250° to 400°C an empirical relationship between the reaction rate and pressure is proposed where the rate is a function of . However, since none of the reaction mechanisms was determined, the significance of the pressure dependencies is not known. Two different initial reactions were obtained. One in the range 96deg; to about 250°C at of 70 and 150 mm Hg and 96°–400°C at of 430 mm Hg showed a gradual increase in the rate of hydrogen consumption until the rate became linear. The other initial reaction followed the parabolic rate law in the range of about 250°–400°C at of 70 and 150 mm Hg.