Kinetics of dissolution of uranium metal foil by alkaline hydrogen peroxide

To develop a new process for the production of 99Mo using low-enriched uranium targets, uranium dissolution in alkaline hydrogen peroxide was studied. Molybdenum-99 is a parent of the widely used medical isotope 99mTc. The rates of uranium dissolution in alkaline hydrogen peroxide solution were measured in an open, batch-type reactor and were found to be a 0.25th order reaction with respect to equilibrium hydrogen peroxide concentration. In general, uranium dissolution can be classified as a low-base (<0.2 M hydroxide) and a high-base (>0.2 M hydroxide) process. In the low-base process, both the equilibrium hydrogen peroxide and the hydroxide concentrations affect the rate of uranium dissolution. In the high-base process, uranium dissolution is independent of alkali concentration; the presence of base affects only the equilibrium concentration of hydrogen peroxide. An empirical kinetics model is proposed and discussed