Studies on the dissolution kinetics of ceramic uranium dioxide particles in nitric acid by microwave heating

The kinetics of dissolution of uranium dioxide particles in 4–8 M (M = mol/L) nitric acid by microwave heating has been studied. It is supposed that the UO2 particles dissolve homogeneously in the form of spherical particles. The dissolution process can be dealt with the well-known shrinking core model. The results show that under the 600 W microwave field, the dissolution of UO2 particles is controlled by the product layer diffusion at the temperature of 90–110 °C. The average activation energy for the dissolution of UO2 particles in 4–8 M nitric acid was calculated to be 73.2 ± 1.8 kJ/mol from Arrhenius plots.