Summary The purpose of the work is to study the influence of the electrodes geometry and the mutual arrangement of functional elements in the working space of a metallization electrolyzer on the distribution of the oxygen flux density in the electrolyte, as well as on the distribution of electric and temperature fields. In a computer model, the stationary operation mode of the electrolyzer for processing spent nuclear fuel immersed into the LiCl molten salt with the addition of Li2O was studied. The calculations were performed using the ANSYS software package. We studied eight designs of the electrolyzer, which differ in the immersion depth of the anodes into the melt as well in the types anode protective covers and the cathode baskets. Verification based on the comparison of the computer modeling with experimental data indicates the adequacy of the models used. The electrolyte velocity field and the temperature field are calculated, as well as the steady‐state picture of the distribution of electric current density over the working space of the electrolyzer. The efficiency of the electrochemical cell is determined.