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This program utilized the available analytical tools within the allocated funds to develop a sound technical basis (minimizing risk to the extent possible) for the recommended change to the current baseline DWPF operations. Test protocols and methodology established through the recent work by Stone and Lambert (2000) for MB2 form the foundation used to assess melt rate for MB3. The primary tools to be utilized include: laboratory-scale isothermal tests and melt rate furnace tests. Additional tests and/or analytical tools will be utilized as warranted. Lambert et al. (2001) discussed additional tests that should be performed prior to implementation of a frit or chemical processing change in DWPF (e.g., slurry-fed melt rate and mini-melter tests). This report discusses the primary assessment of potential frit changes on various properties via model predictions. It should be noted that models to directly assess melt rate are not available (or do not exist). However, the "systems approach" concept (Jantzen 1986) will be applied to ensure that although a candidate frit may improve melt rate other properties (e.g., durability, liquidus temperature (T L), and η) will not be compromised. Property-composition models will be used to assess the impact of a range of frit compositions on various properties. A limited number of tests will be performed on critical properties of interest in an effort to confirm model predictions and/or reduce technical risks. This report is one in a series of reports that provide details on the MB3 melt rate improvement task. Lambert et al. (2001) provided the recommendations resulting from this integrated effort. The focus of the current report is on the joint Savannah River Technology Center (SRTC) / Pacific Northwest National Laboratory (PNNL) frit development and model assessment activities leading to candidate frit compositions to improve melt rate for MB3. Section 2 of this report provides a brief discussion of previous frit development activities for the Defense Waste Processing Facility (DWPF). Section 3 describes the objectives of the overall program to improve melt rate for MB3. The MB3 waste composition is discussed in Section 4. Section 5 presents the SRTC / PNNL frit development and model assessment activities. In Sections 6 and 7 we describe a limited number of tests that were performed on critical properties of interest (durability and η) in an effort to validate model predictions and reduce technical risks. Section 8 addresses technical issues regarding SME acceptability for candidate Frit compositions and provides input to the selection process for those glasses that have been shown to have an improved melt rate relative to the current Frit 200 baseline. Section 9 presents a summary and conclusions regarding the frit development and model assessment activities. This work is being performed in response to Technical Task Request (TTR) #HLW/DWPF/TTR-00-0044, DWPF Macrobatch 3 Melt Rate Study. Immobilization Technology Section WSRC-TR-2001-00131 Savannah River Technology Center Rev....

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This report has been reproduced directly from the best available copy. Executive SummaryPreliminary glass formulation work has been initiated at Pacific Northwest National Laboratory (PNNL,) and the Savannah River Technology Center (SRTC) to support immobilization efforts of Idaho National Engineering and Environmental Laboratory (INEEL) high activity waste (HAW). Based on current pretreatment flow sheet assumptions, several glasses were fabricated and tested using an "All Blend" waste stream composition which is dominated by the presence of ZrOz (Le., approximately 80 wt%). The results of this initial work show that immobilization via vitrification is a viable option for INEEL HAW for this specific waste stream. Waste loadings of at least 19 wt% can be achieved for the "All Blend" stream while maintaining targeted processing and product performance criteria Preliminary data suggest that higher waste loadings may be acheivable. These waste loadings translate into ZrOz contents in excess of 15 wt% in the final glass waste form. The developed frits are based on the alkali borosilicate system. Although the results indicate that vitrification can be used to immobilize the "All Blend" waste stream, the glasses compositions are by no means optimized.SRTC and PNNL recommend the following frit composition be used in the initial INEEL scaled melter run utilizing a simulated "All Blend" waste stream: The target glass composition meets all targeted primary processing and product performance criteria.Liquidus temperature of B L 9 (glass) is below 1050°C with Na2ZrSi207 identified as the primary crystalhe phast -;.f;msity at 1150°C is approximately 60 Poise (6.0 Paos). Durability results (as defined by the PCT) indicate that the normalized B, Na, and Li releases are approximately c:, uraer of magnitude less than those of the EA glass and are similar to other high level waste glasses produced for DWPF.SRTC and PNNL also recommend that INEEL fabricate and test (on a laboratory-scale) BL-9 to confirm that the glass meets the specifications prior to melter processing. The results of the corrosion tests with BL-9 should also be considered prior to running this particular glass. This study has not addressed scale-up issues (Le., crucible scale to melter scale). One concern that was only partially addressed was the devitrification potential within the drain tube during melter idling. Although the limited results suggest that devitrification may occur within the drain tube, based on the type and extent of devitrification for a single data point, the crystals will readily redissolve at 105OOC within 4 hours. The overall strategy of this Tanks Focus Area (TFA) Technical Task Plan (TTP)' is three fold: 6 LIST OF TABLES(1) identify a glass forming system that optimizes properties and loadings of specific INEEL high activity waste streams,(2) develop a glass composition region (or regions) to cover glasses from each individual waste streams (sodium bearing waste, AI-calcine, andlor Zr-calcine) or b...

This report was prepared by Westinghouse Savannah River Company (WSRC) for the United States Department of Energy under Contract No. DE-AC09-96SR18500 and is an account of work performed under that contract.