Executive SummaryPacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Waste Treatment Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). As part of this, the Pretreatment Engineering Platform (PEP) is designed and constructed as part of a plan to respond to issue M12, "Undemonstrated Leaching Processes," raised by the WTP External Flowsheet Review Team (EFRT). The PEP replicates the WTP leaching process using prototypic equipment and control strategies. The approach for scaling PEP performance data to predict WTP performance is critical to the successful resolution of the EFRT issue. This report describes the recommended PEP scaling approach. Results and Performance Against ObjectivesThis report describes the scale-up methodology for PEP results as authorized through Subcontract Change Number SCN-26. The technical approach was a set of internal objectives that were satisfied as summarized in Table ES.1. Review the rationale for the PEP scale of 4.5. YesThe rationale for the PEP scale of 4.5 was reviewed, documented, and endorsed.Define the technical basis for the approach in scaling PEP performance data to predict WTP performance. YesThe unit operations of the WTP replicated in the PEP were analyzed to define scaling approaches based on established engineering analysis techniques.Define how PEP performance data will be used to predict WTP performance.Yes Anticipated PEP performance data were analyzed and cross-referenced to the appropriate WTP performance parameters.Analyze the PEP system to identify scaling issues and consider their potential impacts and mitigation approaches. YesThe PEP design was considered in terms of scale-up based on maintaining similitude. A number of scaling issues were identified. A mitigating test approach was recommended.Provide input to test conduct and data requirements.Yes A test approach was recommended based on scaling issues. Quality RequirementsPNNL implements the RPP-WTP quality requirements by performing work in accordance with the River Protection Project -Waste Treatment Plant Support Program (RPP-WTP) Quality Assurance Plan (RPP-WTP-QA-001, QAP). Testing and analytical activities were performed to the quality requirements of NQA-1-1989 Part I, Basic and Supplementary Requirements, NQA-2a-1990 Task MethodologyThe task described in this report essentially involved three activities:1. A review of the applicable WTP unit operations and the PEP design and operational approach to achieve the desired M12 objectives. The PEP design was well-advanced when this task was initiated, so there was no opportunity to effect design changes. In particular, the scale factor of 4.5 (meaning the PEP is 4.5 linear times smaller than the WTP) was already established, but a review indicates its selection is sound. A review of the fundamental theory underpinning the applicable processes and physical and chemical phenomena (leaching...

Testing SummaryThe U.S. Department of Energy (DOE) Office of River Protection's Waste Treatment and Immobilization Plant (WTP) will process and treat radioactive waste stored in tanks at the Hanford Site. The waste treatment process in the pretreatment facility will mix both Newtonian and non-Newtonian slurries in large process tanks. Process vessels mixing non-Newtonian slurries will use pulse jet mixers (PJMs), air sparging, and recirculation pumps. An anti-foam agent (AFA) will be added to the process streams to prevent surface foaming but may also increase gas holdup and retention within the slurry.Some gas retention tests that were carried out in nonprototypic systems-bubble columns and impeller-mixed vessels-indicated trends that posed process and flammable-gas concerns . Both types of nonprototypic results indicated that the presence of AFA in a chemical simulant of Hanford Tank 241-AZ-101 high-level waste (HLW) might increase gas retention by a factor of 10 or more over that in clay without AFA, the simulant on which WTP design studies were based (see Section 1.2). In addition, the increase over clay holdup was greater at lower simulant yield stress, implying that the 30-Pa simulant results, which had been used for WTP design, might not bound gas retention.The work described in this report addresses gas retention and release in simulants with AFA through prototypic testing and analytical studies. This test program was established to determine whether the AFA has as strong an effect in a large-scale prototypic mixing system as it did in the small-scale nonprototypic tests. Gas holdup and release tests were conducted in a 1/4-scale replica of the lag storage vessel operated in the Pacific Northwest National Laboratory (PNNL) Applied Process Engineering Laboratory using a kaolin/bentonite clay and an AZ-101 chemical simulant with non-Newtonian rheological properties representative of actual waste slurries. Additional tests were performed in a smallscale mixing vessel in the PNNL Physical Sciences Building using liquids and slurries representing major components of typical WTP waste streams to address the fact that simulants delivered to the WTP will come from other tanks in addition to 241-AZ-101. Analytical studies were directed at discovering how the effect of AFA might depend on gas composition, and a model was developed for predicting the effect of AFA on gas retention and release in the WTP, including the effects of mass transfer to the sparge air.The prototypic gas retention and release tests performed in this test program indicate that gas holdup with AZ-101 simulant with AFA is higher than it is in clay, but not to the extent that initially raised WTP design concerns. In addition, the trend to a higher increase in holdup with decreasing simulant yield stress was not seen in the prototypic system. The work at PNNL was part of a larger program that included tests conducted at Savannah River National Laboratory (SRNL) that is being reported separately. SRNL conducted gas holdup tests in a small-scale m...

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