Thermal history and crystallization characteristics of the DWPF glass waste form

The Defense Waste Processing Facility (DWPF) at the Savannah River Site will immobilize high-level radioactive waste by incorporating it in a stable borosilicate glass waste form suitable for long term storage in a geologic repository. The thermal history of the canistered waste form to be produced in DWPF was determined during filling and subsequent cooldown operations by simulating DWPF production conditions. Samples of simulated waste glass of projected compositions for the DWPF have been exposed to the thermal regimen recorded during this simulation of canister production. These glass samples have been characterized using scanning electron microscopy to identify any crystalline phases that are present.