Technical Bases for the DWPF Melter Off-gas Flammability Control under the Glycolic-Acid Flowsheet

The Defense Waste Processing Facility (DWPF) at the Department of Energy’s (DOE) Savannah River
Site (SRS) will undergo a flowsheet change in 2016 by replacing formic acid with glycolic acid as the
baseline reductant for the high-level waste (HLW) melter feed. Prior to implementation, the processability
of the new flowsheet feeds through a melter was demonstrated during the Cold-cap Evaluation Furnace
(CEF) test, which lasted for 24 days with round-the-clock feeding and pouring. Concurrently with the
melter demonstration, the required data for the development of the DWPF melter off-gas flammability
safety basis for the new flowsheet were also collected: (1) steady state off-gas data with the melter vapor
space temperature held constant for two hours each at 700, 600, 500, 400, 350, and <300 °C, (2) off-gas
surge data for both condensable and non-condensable flows, and (3) additional steady state data using
feeds spiked with excess antifoam. Some of the key results from these runs are presented along with
subsequent data analysis and theoretical treatment performed in order to develop the technical bases for
the melter off-gas flammability control under the new flowsheet.