Vitrification tests in a continuous ceramic-lined melter have been completed with simulated radioactive wastes typical of those existing at the Savannah River Laboratory and at U.S. Department of Energy’s Hanford Laboratory. The results of these experiments suggest that immobilization of radioactive waste by vitrification is a promising approach for nuclear waste management. Process rates ranging from 25 to 160 kg/h were observed for simulated powdered waste glasses in the liquid-fed continuous melter. Entrapment of gas in glass bubbles or foaming at the chemical reaction layer caused a marked decrease in the processing rate. Several chemical blends were tested to assess their meltability and susceptibility to foaming. Foaming at the reaction layer was avoided in all but one of eight chemical blends. Differences in the amount of powder accumulated above the molten glass and the subsequent meltdown times strongly indicated that major variations in the meltability existed between the various chemical blends. Prototypic sized canisters (0.4, 0.61, and 0.91 m in diameter and 2.9 m tall) were filled and examined. Canisters were filled at an average rate of 76 to 93 kg/h while standing in air. The homogeneous glass product filled the canisters except for some rippled gaps at the canister wall. Gaps up to 6.4 mm were found. Unless, the radioactive decay heat exceeds the concentrations in existing wastes by a factor of 10 or more, the gaps are believed to be acceptable.