United Kingdom Atomic Energy Authority RESEARCH GROUPnTHE OXIDATION OP URANIUM DIOXIDE BY WATER VAPOUR UNDER REACTOR IRRADIATION

摘要

Semi-quantitative experiments have been carried out to investigate the stability of UO2 in contact with water vapour under irradiation. The data, although limited to temperatures of 80℃ and water vapour pressures below one atmosphere, indicate that oxidation is brought about mainly by oxygen produced during radiolytic decomposition of the water vapour. Oxidation rates may therefore be calculated from a knowledge of GH2 :an estimate based on extremely pessimistic assumptions suggests that the oxidation rate of pellets in defected cans in a steam-cooled reactor will be low.nSubsidiary data provide evidence for the oxidation of U3Og to UO3 in the presence of irradiated water vapour and of oxygen. Data obtainedin the presence of liquid water separated from the fissile powder are ambiguous;the possibility of an enhancement of water decomposition by a chemisorption effect is suggested.