Research on Actinide Chemistry in Nuclear Fuel Cycle

The basic and fundamental chemical technologies applicable to the various fields of nuclear fuel cycle have been developed through this project. The chemical behaviors of actinide behavior in three different types of phases such as high-temperature molten salt, aqueous solution, and solid state nuclear fuel was investigated using spectroscopic and electrochemical measurement systems. Many reliable data were produced through the establishment of the physicochemical measurement system. In the sub-project I, the oxidation/reduction of lanthanide and actinide ions in the multi-component molten salts was investigated, and the electrochemical and spectroscopic measurement systems for the quantitative determination of high concentration of actinides were established. Many valuable data such as activity coefficient, diffusion coefficient, conductivity, etc., were also obtained. In the sub-project II, solubility for Pu hydroxide, actinide (U, Am) complexation, and actinide (U, Am, Np) adsorption at the interface were investigated with regard to the high-level radioactive waste management and disposal, In the sub-project III, elemental distribution in a irradiated fuel, fuel/cladding chemical interaction (FCCI), and leaching behaviors of nuclear fuel, etc., were investigated.