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2011-Sustainable Industrial Processing Summit
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| Editors: | Florian K |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2012 |
| Pages: | 630 pages |
| ISBN: | 978-0-9879917-2-0 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Electrochemical and Diffusion Study of Multi-Component Lanthnides in LiCl-KCl Eutectic
Biplab Sarma1; Krishnan Raja2; Swomitra Mohanty1; Manoranjan Misra2;1UNIVERSITY OF UTAH, Salt Lake City, United States; 2UNIVERSITY OF UTAH, Salt lake City, United States;
Type of Paper: Regular
Id Paper: 220
Topic: 6
Abstract:
Pyrometallurgical processing using LiCl-KCl molten salt system is considered for safe recovery of proliferation resistant nuclear fuel elements from the spent fuel. Pyrometallurgical process is preferred because of the stability of the molten salts to high radiation and shorter cooling times. The major constituents of the fission products are lanthanide series elements, which have electrochemical behavior close to that of actinides. Therefore, very careful control over the process parameters is required for an efficient separation process. Most of the available thermodynamic data on the molten salt systems pertain to binary or ternary systems. When multiple fission product elements are present in the electrolyte, the reduction behavior of the actinides could be significantly altered because of possible under potential reduction of lanthanides and slower diffusion kinetics of actinides. This presentation reports the variations in melting point and electrochemical behavior of LiCl + KCl eutectic mixture containing multi-components of RECl3 additions. Cyclic voltammetry results of binary, ternary, and quaternary LnCl3-(LiCl-KCl)Eutectic systems at 500°C indicated that the incipient potentials of cathodic reduction waves shifted to less negative values with increased additions of lanthanide components. The shift in the reduction potentials could be attributed to the free energy change associated with formation of mischmetal solid solutions and decreased stability of the solvated clusters of lanthanides in the molten salt. The positive shift of the reduction potentials of multi-component lanthanide system indicates that enrichment of fission products in the re-processing cell could detrimentally affect the separation of actinides from the lanthanides. No significant change in the melting temperature was observed with the addition of multiple lanthanide chlorides o the LiCl-KCl eutectic.