Demonstration of the solidification of high-level radioactive waste by the pot, spray, and phosphate glass solidification processes has been successfully completed by Battelle-Northwest. More than 50 million curies of radionuclides were processed and collected in 6-, 8-, and 12-in. diam containers during 33 engineering-scale demonstration runs in the Waste Solidification Engineering Prototypes (WSEP). The maximum self-generating heat rate values in the solidified wastes for an 8-in.-diam pot ranged from 205 W/liter for the spray solid to 85 W/ liter for the pot calcine. Wastes equivalent to those from thermal power reactors with exposures as high as 45 000 MWd/MT at 30 MW/MT were demonstrated. The WSEP auxiliary equipment consisting of an evaporator, an acid fractionator, filters, and a caustic scrubber reduced radionuclides in the stack gas to well below government release limits. The final liquid effluent from WSEP contains radioruthenium that is 104 to 106 times allowable government release values. Strontium and other nonvolatile materials are present to a much smaller extent. Initial studies indicated that the effluent water and acid streams from the waste solidification processes are sufficiently low in volume and radioactivity that they can be reasonably recycled into the fuel reprocessing plant operation. The pots of solidified wastes from the WSEP runs are undergoing testing to determine the effects of storage temperature (air or water), radiation, and feed type on the physical and chemical properties of the solidified wastes.