Advances in the Use of Carbon Anodes for Pyrochemical Electroreduction of Used Nuclear Fuel
Carbon (graphite) is commonly used in commercial molten salt processes within the ore refining industry. It is cost effective, readily available, and a logical choice for scale-up needs. However, different chemistries result from this change in anode materials in both the salt and off gas streams. Instead of forming oxygen at a platinum anode, CO/CO2 becomes the byproduct gas. Although initially insoluble, CO/CO2 residence time within the LiCl-Li2O salt is thought to be problematic because of the formation of reactive carbon species, with respect to the metal, that are soluble and could lead to undesirable side reactions in the system.
This report will discuss an advanced test cell for evaluating the use of carbon as an anode material for the electroreduction of UO2 to uranium metal in molten LiCl-Li2O. We will present design challenges and report on the implementation of advances for the accommodation of process changes with respect the new anode material. Finally, preliminary results on the efficiency and chemical effects of carbon anodes will be discussed.
- Laszlo Redey and Karthick Gourishankar, “Direct Electrochemical Reduction of Metal-Oxides” US Patent US6540902 B1, Granted April 1, 2003
- S. D. Herrmann, S. X. Li, M. F. Simpson and S. Phongikaroon, Separation Science and Technology 2006, 41, 1965-1983.