Oxidation of UO2by High-Pressure Steam

Abstract

Thermodynamically, the oxygen potential of pure steam increases as the pressure increases. As a result, high-pressure steam can produce more highly oxidized urania than can steam at atmospheric pressure. Oxygen-to-uranium ratios as high as 2.60 can theoretically be attained in steam at 150 atm and temperatures near 1600/sup 0/K. Oxidation to this extent can render the fuel nearly as important a source of hydrogen as the cladding in severe fuel damage accidents. Fuel oxidation by steam, however, is endothermic and provides a heat sink rather than a heat source.