Rheological properties of DWPF sludge batch-two radioactive slurries

NUCL 76

Terri L. Fellinger, Eric K. Hansen, and David C. Koopman. Savannah River Technology Center, Westinghouse Savannah River Company, Aiken, SC 29808
The Defense Waste Processing Facility (DWPF) at Savannah River Site is currently processing Sludge Batch 2 (a 500,000 gallon caustic slurry of HLW) for geological disposal. Rheological measurements on this batch are necessary to identify potential mixing and pumping problems during transfer of the batch to the DWPF and during DWPF processing. Sludge slurry samples were transferred to Savannah River Technology Center where rheological properties were measured remotely. Yield stresses and consistencies were obtained from flow curves (shear rate vs. shear stress). Results indicated that the consistency of the original slurry was such that it could be pumped to the DWPF, but was too high to be processed in the DWPF. Lowering the pH of the slurry decreased its consistency. However, additional acid was added to ensure that the final slurry (a mixture of waste and glass forming compounds) could be pumped to the melter. Rheological properties of other radioactive HLW will also be discussed.