We have proposed a reprocessing process based on the dissolution of spent fuels in aqueous carbonate solution. In order to develop such a reprocessing process, anodic dissolution experiments were carried out by using a simulated spent fuel pellet in (NH 4 ) 2 CO 3 solution. The dissolution rate constant of the simulated fuel pellet at 323 K was estimated as 3:1Â10 À6 molÁcm À2 Ámin À1 , which is comparable to that in 5 molÁdm À3 HNO 3 solution containing 0.01 molÁ dm À3 HNO 2 at 323 K. The dissolution rate and the current efficiency for the dissolution of simulated fuel pellet in (NH 4 ) 2 CO 3 solution were found to decrease with the elapse of time. Furthermore, in order to examine dissolution behavior, the surface conditions of the pellet before and after the dissolution experiments were analyzed with the scanning electron microscopy and the energy dispersive X-ray spectroscopy. It was found that neat UO 2 matrix exists on the dissolved surface and a decrease in the dissolution rate and the current efficiency is caused by the increase in such surface area on the pellet.During the dissolution experiments, precipitates of the simulated fission products were observed on the pellet and in (NH 4 ) 2 CO 3 solution used as the electrolytic solution. Analyses of the electrolytic solution revealed that most of the simulated fission products, i.e. alkaline earth and rare earth elements, are precipitated in high ratios. From these results, it is expected that the anodic dissolution of spent fuels and the separation of fission products by precipitation can be performed simultaneously.