A photo-induced dissolution of UO2

The objective of this study is to dissolve UO2 under low temperature and low nitric acid concentration by photochemical reaction. UO2 powder, green pellet and sintered pellet were used for this study. Nitric acid was used as dissolution solvent in the concentration range of 0.5M to 4M. And also, hydrogen peroxide and various metal nitrate salts were used as oxidant in order to accelerate the dissolution rate of UO2 sintered pellet under UV ir radiation. The photo-reactor used for this work is equipped with Hg-lamp emitting 254nm of wavelength and its power is 120W. The work scope of this study is as follows: (1) photo-absorption characteristics of nitric acid solution, (2) dissolution of UO2 powder, (3) effect of metal ion on dissolution of UO2 sintered pellet, (4) dissolution of UO2 target in simulated solution, (5) dissolution of mechanism of UO2 by photochemical reaction. As main results, UO2 sintered pellet was hardly dissolved under UV irradiation, but was rapidly dissolved by using H2O2 or metal ions such as oxidant. (author). 40 refs., 4 tabs., 30 figs