(632a) Development of Coal-Carbon Limit in Fluidized Bed Steam Reformer (SBSR) Testing

Modeling and testing were initiated to determine the maximum carbon concentration in a new waste stream, a product of the Fluidized Bed Steam Reformer (FBSR) at the Savannah Rive Site (SRS). The carbon limit is designed to prevent a flammable carbon monoxide concentration from developing during processing of high-level radioactive waste (HLW).

Historically, carbon in various forms has been present in all of the sludge processed in the SRS Defense Waste Processing Facility (DWPF). Sludge can contain coal and carbonate as the primary carbon species. The new FBSR waste stream is much higher in coal and carbonate than has been processed in the past. The sludge and FBSR product are combined and processed with nitric and formic acid to neutralize the waste, reduce Hg and Mn, destroy nitrite, and modify the slurry rheology, increasing the carbon concentration in the resulting melter feed.

Modeling was used to estimate the carbon limit of the FBSR product stream. A series of experiments with added FBSR product and sludge simulant will be completed in June 2010 in SRS's Aiken County Technical Laboratory. Processing included sludge concentration, a Sludge Receipt and Adjustment Tank (SRAT) cycle and Slurry Mix Evaporator (SME) cycle. This was the first demonstration with the added FBSR stream. A gas chromatograph was used throughout the experiment to compositionally characterize the offgas. The main objective for the experiment was the determination of redox and carbon concentration of the melter feed. Results of this testing will be reported.