Reaction of Hydrogen with Uranium

Abstract

The reaction of hydrogen with uranium to produce uranium hydride was studied in the temperature range 96~176 at pressure levels of p -P0 equal to 430, 150, and 70 mm of mercury (where p is system pressure and p0 is the plateau dissociation pressure of the uranium hydride product). Reaction rates followed the linear law. At a given p --p0, the linear rate increased with increasing temperature in the range 96 ~ to about 250~ and decreased with increasing temperature from about 250 ~ to 400~ Variation of the linear rate with temperature and pressure in the range 96 ~ to about 250~ is given by the equation: r = 4.11 X 10-~p ~/4 exp (-1820/RT) where r is in units of ml/cm~/sec and p is in units of mm Hg. In the range from about 250 ~ to 400~ an empirical relationship between the reaction rate and pressure is proposed where the rate is a function of p -p~/po. 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 96 ~ to about 250~ at p -p0 of 70 and 150 mm Hg and 96~176 at p -p0 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 oi about 250~176 at p --p0 of 70 and 150 mm Hg.

Pyrophoric behaviour of uranium hydride and uranium powders

“…Albrecht and Mallett [7] shows maximum reaction velocity at about 280°C and Hashino and Okajima [8] indicates 268°C as a limit temperature. Rate decrease at higher temperatures is due to decomposition reaction hindering the hydration reaction process.…”

Mathematical analysis of the hydrogen–uranium reaction using the shrinking core model for hydrogen storage application

“…9 [12] Reaction kinetics of high purity uranium rods with hydrogen was studied over the temperature range of 96e400 deg C and hydrogen overpressure of 70e430 mm Hg.…”

Hydrogen Isotopic Effects of Uranium Hydrides: First-Principles Calculations

“…Nevertheless, the difficulties associated with handling uranium hydride relate to its radioactivity and high pyrophoricity with oxygen [7]. Particularly, the coexistence of uranium and the hydride challenges monitoring the composition of the reactants [8][9][10][11].…”