Kinetics of UO 2 (s) Dissolution in the Presence of Hypochlorite, Chlorite, and Chlorate Solutions

The influence of hypochlorite, chlorite and chlorate in the UO 2 dissolution rate has been studied experimentally using a continuous flow-through reactor. Uranium concentration in each outflow solution was measured as a function of time and dissolution rates were determined once the steady-state was reached. The results obtained show that the influence of the hypochlorite anion concentration on the UO 2 dissolution rate can be expressed by the following empirical equation r diss = 10 -8.7±0.1 •[ClO - ] 0.28±0.04 The dissolution rates obtained in this work were higher than those previously determined in presence of either oxygen or hydrogen peroxide using the same experimental methodology. In contrast, neither chlorate nor chlorite had any significant effect on the UO 2 dissolution rates under the experimental conditions of this work.