b'Dissolution PhenomenaNovel chemistry facilitates used nuclear fuel reuse in fast reactor systems where of Used Nuclear Oxide Fuel intransuranium constituents can be burned.Molten Salt Systems T he objective of this research was to demonstrate and characterize a novel technique for dissolution of used nuclear oxide fuel constituents in select molten salt systems to facilitate their reuse in fast reactor systems. Used nuclear oxide fuel constituents were converted into molten chloride systems for potential use as: (1) molten chloride salt reactor fuel; or (2) a head-end step to group actinide metal recovery via electrochemisry. Both conversion options TOTAL APPROVED AMOUNT:facilitate used nuclear oxide fuel reuse in fast reactor systems, where transuranium $1,127,500 over 3 years constituents can be burned as a metal fuel or a molten chloride salt fuel. Dissolution of used nuclear oxide fuel constituents were demonstrated by immersing fuel PROJECT NUMBER:particulate into a molten salt system containing a base chloride salt (e.g., alkali 19A39-059 metal chlorides) and a chlorinating agent (e.g., uranium trichloride). Applying an PRINCIPAL INVESTIGATOR:electric current to some oxide fuel assisted dissolution by promoting conversion Steven Herrmann of transuranium, lanthanide, alkaline earth, and alkali oxide species from the fuel into chlorides. Noble metal fission products were not converted to chlorides in CO-INVESTIGATORS: this system and were consequently removed with uranium oxide in an insoluble Steven Frank, INL solid form. Lithium chloride, sodium chloride, potassium chloride, or combinations Brian Westphal, INL thereof, were used as the base salts in this system. A lithium-potassium chloride Haiyan Zhao, University of Idaho base salt best served subsequent removal of group actinide metals while sodium chloride was better suited for a molten chloride salt reactor fuel. Oxide fuel preconditioning and in situ reducing conditions along with elevated temperature and uranium trichloride concentrations were the primary parameters promoting used nuclear oxide fuel constituent dissolution in accordance with identified reaction mechanisms during this demonstration, where 9099+% of transuranium and reactive fission product constituents dissolved into the subject molten salt systems. High-purity uranium trichloride was synthesized and characterized in this study to support the oxide fuel dissolution.TALENT PIPELINE:Steven Herrmann, student at University of IdahoPUBLICATION:Herrmann, S. D., B. R. Westphal, S. X. Li, and H. Zhao, Parametric study of used nuclear oxide fuel constituent dissolution in molten LiCl-KCl-UCl3, Nuclear Technology (2021) Ahead-of-Print. Available at: https://doi.org/10.1080/00295450.2021.1973180.(a) Declad used nuclear oxide fuel. (b) Synthesized lithium-potassium-uranium chloride salt ingot.58'