Melting method for waste

Voltage is applied to at least a pair of electrodes in a refractory furnace to apply melting treatment to radioactive wastes and put them into molten salts and molten materials. In this case, not-molten wastes are supplied between the molten portion of the wastes and an inner wall of the refractory furnace so as to form a heat insulation layer. Since the wastes are thus melted in the refractory furnace, it is excellently heat efficient upon melting, and since the wastes are melted subsequently while forming the heat insulation layer, inexpensive materials with lower heat resistance compared with existent materials can be used. Accordingly, a refractory furnace can be constructed economically. (T.M.)