Numerical simulation analysis of the impact of cold-cap coverage on energy consumption in a HLLW joule-heating ceramic melter

Computational fluid dynamics (CFD) technology was utilized to conduct a numerical simulation of the Joule-Heating Ceramic Melter (JHCM) employed in vitrification plants in China (VPC), with the aim of evaluating the effects of varying cold-cap coverage on energy consumption and efficiency. The simulation models were developed based on a representative glass formula for high-level liquid waste (HLLW) with elevated sulfur and sodium content, incorporating critical material parameters such as density, specific heat capacity, conversion degree, thermal conductivity, electrical conductivity, and kinematic viscosity. These parameters were essential for accurate predictions of temperature distribution and energy dynamics within the melter. The CFD model results indicate that increasing the cold-cap coverage significantly reduces energy loss by improving system heat retention, thereby decreasing the power input required to sustain operational temperatures. This result highlights the necessity of optimizing cold-cap coverage to enhance the efficiency and cost-effectiveness of HLLW vitrification processes. The findings offer valuable guidance for the design and operation of advanced JHCM systems, promoting more sustainable and efficient nuclear waste management approaches.