Abstract The molten salt technique is considered to be a feasible technique applicable for the removal of uranium from the spent NaF (fillers). Simple spent NaF or NaF with NaCl, i.e. mixed salt, was used as an electrolyte and the uranium concentrations in the bath, pre-treatment condition, electrolytic temperature, current density, etc. were given as parameters in this experiment. Results from the fundamental experiments showed the potential applicability of the molten salt technique for the removal of uranium from spent NaF.