R&d Activities for Partitioning and Transmutation in Korea

According to the Korean long-term plan for nuclear technology development, KAERI is conducting a R&D project on the partitioning and transmutation (P&T) of long-lived radionuclides. The study for the partitioning is focused on the development of pyroprocessing based on an electrorefining of actinides because it is a kind of proliferation-resistive technology, where all the transuranic metals are separated together as a mixture. The major experimental items of this study include an electrorefining, electrowinning, cadmium evaporation and a molten salt waste treatment. Various behaviours of the electrodeposition of uranium, rare earths, alkali and alkaline earths in the LiCl-KCl electrorefining system have been examined through fundamental experimental work. As liquid cadmium was employed as the second cathode in this study, its removal by an evaporation, thus leaving transuranic as the final product, was examined. Treatment of the molten salt waste was also investigated by introducing zeolite for the immobilization of the molten salts. As for the transmutation system, KAERI is studying the HYPER (HYbrid Power Extraction Reactor), a kind of subcritical reactor which will be connected with a proton accelerator. Up to now, a conceptual study has been carried out for the major elemental systems of the subcritical reactor such as the core, transuranic fuel, long-lived fission product target, and the Pb-Bi cooling system, etc. In order to enhance the transmutation efficiency of the transuranic elements as well as to strengthen the reactor safety, the reactor core was optimized by determining its most suitable subcriticality, the ratio of the height/diameter, and by introducing the concepts of an optimum core configuration with a transuranic enrichment as well as a scattered reloading of the fuel assemblies.