Projections of the World Energy Council indicate a significant increase in global energy consumption in the medium and long term due to a growing world population and rising prosperity whilst global fossil fuel reserves are in decline. Eighty percent of the world’s energy consumption is generated from fossil fuels and this is unlikely to change in the short and medium term inevitably leading to energy shortfalls. The CO2-less energy of nuclear fuel shows strong potential to meet the future energy demands. However economic, politic and environmental requirements mean that the nuclear industry must adapt its current technology and present fuel usage. A pyroelectrochemical reprocessing system utilising liquid cathode technology could provide an efficient and secure reprocessing cycle essential for reduction in volume and toxicity of nuclear waste and extension of natural nuclear resources. The electrochemistry of aqueous copper(II) and zinc(II) chloride was studied upon a liquid mercury cathode using cyclic voltammetry. Bulk deposition of the Cu upon the liquid mercury cathode was studied using both amperometry and Electrochemical Impedance Spectroscopy. The surface deposits formed by copper deposition upon the mercury liquid cathode were analysed using x-ray powder diffraction and determined to be the rare naturally occurring mineral Belendorffite, Cu7Hg6. Electrochemical diagnostics for surface deposition upon the mercury liquid cathode surface were investigated as a potential analogue system for high temperature liquid cathode systems. Bulk deposition investigation of lanthanum upon the high temperature bismuth system demonstrated transfer of EIS diagnostics for surface growth, with the system demonstrating a similarity to the zinc-mercury ambient system. An electrochemical technique for purifying LiCl/KCl molten salt using an electrolysis technique was demonstrated. The electrochemical cleaning method forgoes the standard chemical treatments that can leave contaminants within the treated salt and results in a cleaner less oxidising molten salt eutectic.