Understanding the Structure and Speciation of Molten LiCl-KCl Using Raman and Ultraviolet-Visible-Near IR Spectroscopic Techniques

• Published in: Meeting abstracts (Electrochemical Society) Vol. MA2020-02; no. 9; p. 1185
• Main Authors: Moon, Jeremy, Phillips, William C., Gakhar, Ruchi, Chidambaram, Dev
• Format: Journal Article
• Language: English
• Published: 23.11.2020
• ISSN: 2151-2043; 2151-2035
• DOI: 10.1149/MA2020-0291185mtgabs

Pyrochemical reprocessing (pyroprocessing) of used nuclear fuel (UNF) is a promising pathway towards closing the nuclear fuel cycle by recycling actinides into new fuel and providing the means to generate durable wasteforms for portions of the UNF that are not able to be recycled. One of the most significant challenges in the advancement of this technology is developing a more complete understanding of the chemistry of the electrolyte molten salts used in the electrorefining process, where fission products, transuranic elements and fuel elements are anodically dissolved into a LiCl-KCl electrolyte, forming a chemically complex mixture. To enhance our understanding of the chemistry of the mixture of molten salt electrolyte and UNF we are studying the structure and speciation of lanthanide and actinide elements dissolved in LiCl-KCl using Raman and ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. These techniques are starting to provide information on the coordination, symmetry, and electronic structure of the dissolved species, which will result in a more complete understanding of the chemistry of these solutions. Results of a Raman spectroscopy study of mixtures of NdCl 3 , SmCl 3 , CeCl 3 , and EuCl 3 with LiCl-KCl and LiCl-KCl-UCl 3 and the development of a system to conduct Raman and UV-Vis-NIR spectroscopy and spectroelectrochemistry will be presented. Acknowledgements: This work was performed under the auspices of the Department of Energy (DOE) under contracts DE-NE0008889, and the US Nuclear Regulatory Commission (NRC) under contracts NRC-HQ-13-G-38-0027 and 31310018M0032. Dr. Kenny Osborne and Ms. Nancy Hebron-Isreal serve as the program managers for the DOE and NRC awards, respectively. For support of furnace design and fabrication work at INL, RG and WCP acknowledge the Laboratory Directed Research & Development (LDRD) Program under DOE Idaho Operations Office Contract DE-AC07-05ID14517 and a subcontract under LDRD (INL) to University of Nevada, Reno via award number 204471 (UNR award AWD-01-00001719); this design served as starting iteration for this work. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1447692. One of the authors, JM, acknowledges the Graduate Research Fellowship from the US National Science Foundation.