Formulation Development for Processing Tank 48H in Saltstone

Salt Program Engineering (SPE) requested research to help evaluate the Saltstone process as a disposition path for the contents of Tank 48H. The main objective of the task was to evaluate the processing and cured properties of Saltstone prepared with Tank 48H material aggregated with other Tank 50H inflows to determine the suitability of Saltstone as a disposition path for the contents of Tank 48H. The Tank 48H waste was aggregated with inhibited water (IW) and a simulant of the recycle stream from the Defense Waste Processing Facility (DWPF). The aggregates targeted three tetraphenyl borate (TPB) concentrations: (1) 5500 mg/L, the aggregate determined from assumptions at the maximum reasonable limits, (2) 1500 mg/L, the aggregate containing the minimum proportion of Tank 48H material that is programmatically acceptable, and (3) 3500 mg/L, the average of the two endpoints. Saltstone prepared with Tank 48H waste aggregated with IW and a simulant of the recycle stream from the DWPF was produced in the Savannah River National Laboratory (SRNL) shielded cells. Processable Saltstone slurry formulations can be prepared with Tank 48H material and both DWPF recycle simulant and inhibited water with concentrations of 1500, 3500, and 5500 mg/L TPB. Toxic Characterization Leaching Procedure (TCLP) extractions were performed on the six aggregates. The extracts were analyzed for benzene, nitrobenzene and mercury. All of the samples passed TCLP. Saltstone was also prepared with a Tank 48H simulant and DWPF recycle simulant. Testing of the fresh Saltstone slurry and cured Saltstone prepared with simulants indicate that neither the fresh nor cured Saltstone is hazardous for ignitability. After transferring Tank 48H material to Tank 50H and prior to processing through the Saltstone Production Facility (SPF), Tank 50H should be sampled to verify processability