Cyclic voltammetric experiment - simulation comparisons of the complex mechanism associated with electrochemical reduction of Zr4+ in LiCl-KCl eutectic molten salt

Nuclear energy increasingly represents an important option for generating largely clean CO2-free electricity and zirconium is a fission product that is expected to be present in irradiated fuels. The present investigation addresses the electrochemical reduction of Zr4+ to Zro in LiCl - KCl eutectic molten salt in the temperature range 425–550°C using cyclic voltammetry (CV), square-wave voltammetry (SWV) and bulk electrolysis. Simulations of the CV data indicate that the initial reduction proceeds through surface confined steps: Zr4+* + 2e− ↔ Zr2+* and Zr2+* + 2e− ↔ Zr* processes (* adsorbed species) followed by a peak-shaped complex diffusion controlled step that consists of a combination of closely spaced processes associated with the reactions Zr4+ + 4e− → Zro and Zr4+ + 3e− → Zr+*. Zr+*, probably in the form of ZrCl* is then further reduced to Zro* at even more negative potentials. The simulations provide the first quantitative analysis of the thermodynamics and kinetics of the Zr4+ reduction in the LiCl-KCl eutectic. © 2012, The Electrochemical Society.

Keywords

Nuclear energy, Zirconium, Fission products, Spent fuels, Molten salts, Thermodynamics

Citation

Fabian, C. P., Luca, V., Le, T. H., Bond, A. M., Chamelot, P., Massot, L., Caravaca, C., Hanley, T. L., & Lumpkin, G. R. (2013). Cyclic voltammetric experiment - simulation comparisons of the complex mechanism associated with electrochemical reduction of Zr4+ in LiCl-KCl eutectic molten salt. Journal of the Electrochemical Society, 160(2), H81-H86. doi:10.1149/2.016302jes