Identifying the speciation of salt-based lanthanides in the presence of molten-salt reactor contaminants | Poster Board #1440

Molten salt reactors (MSR) present advantages over light water reactors, such as higher safety and energy efficiency, convenient waste processing, and the ability to use more abundant thorium instead of uranium as the fuel source. However, there are risks associated with high temperatures and molten salts, which can corrode the reactor parts, so a thorough understanding of the chemical reactions occurring inside the reactor becomes crucial. The molten salts' rheological properties (i.e., viscosity, density) affect the flow and heat transfer properties. The molten salts’ local structure governs the bulk physical properties, and introducing corrosion products such as Cr, Mn, and Ni can change this local structure, affecting the physical properties. Lanthanides were used as a surrogate in this work to explore the speciation of actinides in the presence of corrosion products in molten salts. Lanthanides, corrosion products and excess molten salts were added to an alumina crucible inside a glovebox. The filled alumina crucible was placed inside a quartz tube and sealed under a vacuum. These reactions were heated to 1000 C, slowly cooled to different temperatures (e.g., 600, 700, 800), taken out of the furnace, and quenched at that temperature. Then the excess salt was removed, and the products were analyzed using X-ray diffraction techniques, spectroscopic (UV/Vis, Raman, FTIR) methods and scanning electron microscopy coupled with energy dispersion spectroscopy.