A Molten Salt Aerosol Spectroscopy Approach to Online Process Monitoring in Molten Salt Reactors

Year
2024
Author(s)
Ammon Williams - Material Minimization, Security & International Safeguards Department, Idaho National Laboratory
Ruchi Gakhar - Advanced Technology of Molten Salts Department, Idaho National Laboratory
Qiufeng Yang - Advanced Technology of Molten Salts Department, Idaho National Laboratory
Micah Raab - Material Minimization, Security & International Safeguards Department, Idaho National Laboratory
Cooper Rokop - Material Minimization, Security & International Safeguards Department, Idaho National Laboratory
Adam Butikofer - Advanced Technology of Molten Salts Department, Idaho National Laboratory
Abstract

Recent research and development in molten salt reactors (MSRs) has led to many advanced reactor designs, many of which have demonstrations planned in the next decade. However, a significant challenge that must be overcome before liquid fueled MSRs become viable globally is nuclear material accountancy (NMA) and safeguards. Liquid-fueled MSRs are problematic to safeguards because the nuclear material is in the bulk phase, inventories are constantly changing, and there are many potential outlet pathways that must be monitored, especially in designs coupled with online chemical processing. At the Idaho National Laboratory, we have developed an online process monitoring tool to circulate molten salt through a nebulizer and optical cell, where laser-induced breakdown spectroscopy (LIBS) and ultraviolet-visible (UV-VIS) are applied to track the elemental and oxidation states of the constituents in the salt aerosol. This approach has the potential to provide information on the actinides, fission products, and corrosion in the reactor or process. Preliminary testing in aqueous praseodymium chloride (PrCl3) and neodymium chloride (NdCl3) showed good sensitivity detection limits with developed calibration curves. Additional tests and analysis are ongoing in aqueous solutions while equipment is being scaled up for high temperature molten salt testing. Results for continued aqueous testing as well as a status of the molten salt design and anticipated commissioning are presented.