Development Of A Macro-Batch Qualification Strategy For The Hanford Tank Waste Treatment And Immobilization Plant

The Savannah River National Laboratory (SRNL) has evaluated the existing waste feed qualification strategy for the Hanford Tank Waste Treatment and Immobilization Plant (WTP) based on experience from the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) waste qualification program. The current waste qualification programs for each of the sites are discussed in the report to provide a baseline for comparison. Recommendations on strategies are then provided that could be implemented at Hanford based on the successful Macrobatch qualification strategy utilized at SRS to reduce the risk of processing upsets or the production of a staged waste campaign that does not meet the processing requirements of the WTP. Considerations included the baseline WTP process, as well as options involving Direct High Level Waste (HLW) and Low Activity Waste (LAW) processing, and the potential use of a Tank Waste Characterization and Staging Facility (TWCSF). The main objectives of the Hanford waste feed qualification program are to demonstrate compliance with the Waste Acceptance Criteria (WAC), determine waste processability, and demonstrate unit operations at a laboratory scale. Risks to acceptability and successful implementation of this program, as compared to the DWPF Macro-Batch qualification strategy, include: Limitations of mixing/blending capability of the Hanford Tank Farm; The complexity of unit operations (i.e., multiple chemical and mechanical separations processes) involved in the WTP pretreatment qualification process; The need to account for effects of blending of LAW and HLW streams, as well as a recycle stream, within the PT unit operations; and The reliance on only a single set of unit operations demonstrations with the radioactive qualification sample. This later limitation is further complicated because of the 180-day completion requirement for all of the necessary waste feed qualification steps. The primary recommendations/changes include the following: Collection and characterization of samples for relevant process analytes from the tanks to be blended during the staging process; Initiation of qualification activities earlier in the staging process to optimize the campaign composition through evaluation from both a processing and glass composition perspective; Definition of the parameters that are important for processing in the WTP facilities (unit operations) across the anticipated range of wastes and as they relate to qualification-scale equipment; Performance of limited testing with simulants ahead of the waste feed qualification sample demonstration as needed to determine the available processing window for that campaign; and Demonstration of sufficient mixing in the staging tank to show that the waste qualification sample chemical and physical properties are representative of the transfers to be made to WTP. Potential flowcharts for derivatives of the Hanford waste feed qualification process are also provided in this report. While these recommendations are an extension of the existing WTP waste qualification program, they are more in line with the processes currently performed for SRS. The implementation of these processes at SRS has been shown to offer flexibility for processing, having identified potential processing issues ahead of the qualification or facility processing, and having provided opportunity to optimize waste loading and throughput in the DWPF