0013-4651/2013/160(2)/H81/6/$28.00 © The Electrochemical Society 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. [DOI: 10.1149/2.016302jes] All rights reserved