b'Impurity removal fromCentrifugal and electromotive forces combine in a rotating disc molten salt systems viacollection electrode to remove soluble and insoluble impurities high-speed rotating discquickly and effectively from molten salt systems.collection electrode W ith the advancement of molten salt systems in nuclear operations, including the pyroprocessing of used nuclear fuels, molten salt reactors, and molten salt heat transfer media, the need for online removal of impurities from these systems has become paramount to maintain their effectiveness and promote their longevity. Impurities in the form of fission, transmutation, and corrosion productsincluding soluble and insoluble speciesaccumulate within these systems, some of which can lead to deleterious PROJECT NUMBER:effects in terms of electrochemical cell inefficiencies, product contamination, and 22P1074-013FP component fouling. Prior work with packed-bed ion exchange systems and fractional crystallization for removal of impurities from molten salt systems have not produced TOTAL APPROVED AMOUNT:compelling results to warrant their advancement. $125,000 over 1 yearThe objective of this research was to investigate a novel approach to the in situ removal PRINCIPAL INVESTIGATOR:of impurities from molten salt systems using a high-speed rotating disc collection Steven Herrmann electrode. The electrode was specially designed and fabricated for operation with an off-CO-INVESTIGATORS: the-shelf high-speed rotator. The collection electrode was operated in non-radiological Guy Fredrickson, INL molten salt systems that were representative of those used in the pyroprocessing Haiyan Zhao, University of Idahoof used nuclear fuel. Specifically, lithium chloridepotassium chloride eutectic, containing insoluble graphite fines from the vendor, was heated to form a molten pool and spiked with natural neodymium (III) chloride as a representative fission product impurity. Potentiometery was performed on the salt pool to identify reaction potentials for neodymium metal deposition. The rotating disc collection electrode was then operated at thousands of revolutions per minute both without and with an applied electrode potential. When applied, the electric potential was operated short of depositing neodymium metal, leaving it in a soluble chloride form. The electrode was also operated for different periods of time. Samples of the salt were taken over time as well as before and after the application of electrode potentials. The salt samples clearly identified the removal of insoluble graphite fines from the salt pool. Samples of salt from the molten pool and the collected product identified a several fold increase in the neodymium concentration within the electrode relative to the salt pool. The concentration of neodymium in the collection electrode occurred predominantly when an electric potential was applied. The experiment was repeated with a separate salt loading and similar results were observed. This brief experimental study demonstrated a proof-of-concept for a rotating disc collection electrode to concentrate and remove impurities from molten salt systems. TALENT PIPELINE:Tristan Ence, student at University of Idaho Salt ingot before (top) and after (bottom) operation with69a high-speed rotating disc collection electrode.'