Design and analysis of electrode components for use in spent CANDU fuel reprocessing
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Date
2025-03
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University of New Brunswick
Abstract
Electroreduction experiments were conducted to determine the suitability of platinum-iridium (80 wt% Pt; 20 wt% Ir) and graphite anodes for use in Moltex Energy’s Waste to Stable Salt (WATSS) process. To determine their degradation rates, molten CaCl2-CaO (~10 wt% CaO) was electrolyzed on sample electrodes in open and inert atmospheres. It was determined that the degradation rate of Pt-Ir in open and inert atmospheres was similar, while graphite’s degradation rate was inhibited in inert atmospheres. The main degradation mechanism for Pt-Ir and graphite anodes was found to be pitting corrosion and carbonate cycling, respectively. To verify the WATSS electroreduction stage and alloy formation mechanism, CeO2 pellets (acting as a surrogate for used fuel) were reduced in molten CaCl2-CaO (~0.5 wt% CaO). SEM/EDX and Raman analysis confirmed that cerium metal and cerium oxychloride formed on the cathode. Overall, neither anode is recommended for WATSS but the electroreduction stage has been demonstrated.