A Gas Chromatographic Study on the Kinetics of Uranium Oxidation in Moist Environments

Abstract

Oxidation kinetics of metallic uranium in moist gaseous media and its correlation to the surface morphology were studied by means of a gas chromatographic technique developed for this purpose. The results have substantiated the authors' earlier work which led to the concept of a hydride fracture mechanism for the rapid oxidation at near ambient temperature. Through a series of experiments on the effect of oxygen on the kinetics of the hydrogen forming reaction, an attempt was made to explain the commonly observed low degree of temperature dependence of the linear oxidation rate. Close examination of the morphology of the reaction product layers has indicated a sequence of successively occurring stages of different mechanisms. A speculation was made on the role of hydride formation and its fracture at the metal-to-oxide interface which leads the overall reaction to linearly time dependent kinetics, in which repetition of short segments of a diffusion controlled process is involved.