The Effect of Hydrogen Peroxide Concentration on the Oxidative Dissolution of UnirradiatedD Uranium Dioxide

摘要

The dissolution rate of unirradiated uranium dioxide was studied in batch experiments as a function of hydrogen peroxide concentration (from 10~(-5) to 10~(-3) mol dm~(-3)).Unirrdiated UO_2(s) was used in order to differentiate surface chemical processes from radiolytic effects.Dissolution rates were determined from both uranium release and hydrogen peroxide consumption.Results showed that H_2O_2 consumption rate was higher than UO_2 dissoluiton rate.This observation may indicate that the overall UO_2 oxidative dissolution process would be controlled by the dissolution of the oxidized solid surface.The calculated hydrogen peroxide reaction order was 1 in the H_2O_2 concentration range from 10~(-5) to 10~(-4) mol dm~(-3),while at higher concentrations no clear dependence was observed.