The Effect of Alpha-Radiolysis on UO_2 Dissolution Determined from Batch Experiments with ~(238)Pu-Doped UO_2

摘要

Dissolution experiments were performed with ~(238)Pu-doped UO_2 containing doping levels of ～1-100 Ci/kg UO_2, in 0.1M perchlorate with or without 0.1M carbonate, at pH 9.5, to investigate the effects of α dose-rate on UO_2 dissolution rates and on G_(eff), the fraction of radiolytically produced H_2O_2 supporting dissolution. Dissolution rates increased by only about 10 times for a ～100-fold increase in doping level in both solutions, but increased between 10 and 100 times in 0.1M carbonate, compared to dissolution rates in 0.1M perchlorate. G_(eff) values increased with decreasing doping level, suggesting that the dissolution reaction is limited by the reaction rate between UO_2 and H_2O_2 at high dose rates, but becomes limited by the rate of production of H_2O_2 at lower dose rates.