Abstract
In this paper, the dissolution of the ceramic uranium dioxide particles by the microwave heating has been studied fundamentally. The nitric acid and the UO2 can absorb microwaves significantly because they are polar materials with high value of the dielectric loss factor. It was found that the dissolution ratio of uranium dioxide particles was highly dependent on the temperature and the concentration of nitric acid. The increase in the reaction temperature and nitric acid concentration increased the dissolution rate. The dissolution of uranium dioxide particles in nitric acid solution by microwave heating could be a potential alternative for the treatment of spent fuel from high temperature gas-cooling reactor (HTGR), because the dissolution ratio obtained by microwave heating was much higher than that obtained by conventional heating. When the reaction temperature was higher than 120℃, the ceramic uranium dioxide particles (450-550 μm)dissolved almost completely within 20 minutes. However, more than 60 minutes was needed by the conventional heating.
