The Radioactive Liquid Waste (RLW) generated from the nuclear fuel cycle contains 99% activity associated with the nuclear fuel cycle. The radionuclides are immobilised in an inert borosilicate based glass matrix using a process called "Vitrification". Vitrification is carried out in Joule Heated Ceramic Melter (JHCM) and is a high temperature process occurring at about 900-1000 °C. The heat inside JHCM is generated using electrodes submerged in molten glass by the principle of Joule heat. The electrodes play a vital role in inducing convective currents in the molten glass. A three-dimensional numerical model of JHCM used for vitrification of RLW was developed using CFD methods in COMSOL^® 5.0 Multiphysics software. Electrical, heat, flow and mass transfer fields are coupled in molten glass pool. The model developed was used for simulation and design refinement studies. The effect of orientation of electrodes was investigated using the model in order to improve JHCM design for achieving efficient heating.