APPLICATION OF THE HANFORD THERMITE PROCESS TO INCREASE IMMOBILIZATION OF IN-TANK SOLIDIFIED WASTES

摘要

The Hartford Thermite process is a high-temperature process for conversion of high-level, radioactive wastes to insoluble silicates and aluminosilicates. For application of the process to Hanford's In-Tank Solidified (ITS) waste, statistically designed experiments with synthetic waste demonstrate the optimum thermite charge contains 30 to 40 wt% ITS waste, 15 to 35 wt% FezOs (or alternatively, 15 to 35 wt% MnOz), 15 to 20 wt% silicon metal, and 10 to 25 wt% sand. Ignition of such a charge produces a green-black silicate glass (density = ~2.5 g/cm ;thermal conductivity = ~0. 7 watt/meter °C) whose leach rate in distilled water at 25 °C is in the range 10~7 to 10~5 g/cm2 day. This glass, judging from initial data, should be an excellent vehicle for immobilization of ITS waste.