The work reported here was funded by Washington River Protection Solutions (WRPS). Dave Swanberg with WRPS led the effort and provided both programmatic guidance and technical input to the project team. These screening tests were very laboratory intensive. At Pacific Northwest National Laboratory (PNNL), Ben Williams was instrumental in preparing the Cast Stone specimens and conducting the leach tests. Don Rinehart prepared the simulants. Keith Geiszler, Steve Baum, Igor Kutnyakov, Christian Iovin, and Dennesse Smith analyzed the many samples. Stan Pitman, Mike Dahl, and Karl Mattlin conducted the compressive strength measurements. At Savannah River National Laboratory (SRNL), Vickie Williams was the cornerstone of the preparation and measurement of the Cast Stone fresh properties, Kim Wyszynski and Vickie Williams prepared the simulants, and David Best, Whitney Riley, and Beverly Wall performed the analyses. John Harris with LaFarge graciously provided the dry blend ingredients sourced from the northwest.

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iii SummaryThe Hanford Tank Waste Treatment and Immobilization Plant (WTP) is being constructed to treat the 56 million gallons of radioactive waste stored in 177 underground tanks at the Hanford Site. The WTP includes a pretreatment facility to separate the wastes into high-level waste (HLW) and low-activity waste (LAW) fractions for vitrification and disposal. The LAW will be converted to glass for final disposal at the Integrated Disposal Facility (IDF). The pretreatment facility will have the capacity to separate all of the tank wastes into the HLW and LAW fractions, and the HLW Vitrification Facility will have the capacity to vitrify all of the HLW. However, a second immobilization facility will be needed for the expected volume of LAW requiring immobilization. A number of alternatives, including Cast Stone-a cementitious waste form-are being considered to provide the additional LAW immobilization capacity.The supplemental immobilization waste form must be acceptable for disposal in the IDF. This supplemental immobilization waste form testing plan outlines the testing of the waste form and immobilization process to demonstrate that the Cast Stone waste form can comply with the disposal requirements.Specifications for the supplemental immobilization waste form have not been established. For this testing plan, Cast Stone specifications are derived from specifications for the immobilized LAW glass in the WTP contract, the waste acceptance criteria for the IDF, and the waste acceptance criteria in the IDF portion of the Hanford Facility Resource and Recovery Act (RCRA) Permit issued by the State of Washington. This testing plan outlines the testing needed to demonstrate that the waste form can comply with these waste form specifications and acceptance criteria. The testing program must also demonstrate that the immobilization process can be controlled to consistently provide an acceptable waste form product.

Executive SummaryWashington River Protection Solutions, LLC (WRPS) funded Pacific Northwest National Laboratory (PNNL) to conduct a waste form testing program to implement aspects of the Secondary Liquid Waste Treatment Cast Stone Technology Development Plan (Ashley 2012) and the Hanford Site Secondary Waste Roadmap (PNNL 2009) related to the development and qualification of Cast Stone as a potential waste form for the solidification of aqueous wastes from the Hanford Site after the aqueous wastes are treated at the Effluent Treatment Facility (ETF). The current baseline is that the resultant Cast Stone (or grout) solid waste forms would be disposed at the Integrated Disposal Facility (IDF). Data and results of this testing program will be used in the upcoming performance assessment of the IDF and in the design and operation of a solidification treatment unit planned to be added to the ETF. The purpose of the work described in this report is to 1) develop simulants for the waste streams that are currently being fed and future WTP secondary waste streams also to be fed into the ETF and 2) prepare simulants to use for preparation of grout or Cast Stone solid waste forms for testing.The waste solidification unit to be added to the ETF is expected to receive wastes from three sources on the Hanford Site: 1) the 242-A Evaporator, 2) the ERDF, and 3) the WTP. Chemical simulants were selected to represent each of the three waste streams that the waste solidification unit is expected to receive: 1) condensates from the 242-A Evaporator, 2) leachates from ERDF, and 3) process condensates from the WTP Pretreatment Facility plus the caustic scrubber solution from the WTP LAW melter off-gas treatment system. Chemical simulants of each of the three waste streams were prepared, and will be used in preparing grout specimens for secondary waste grout formulation tests.Before the larger simulant batches were prepared for the grout waste form tests, smaller one-liter batches were prepared to check for chemical interactions and solids formation at the targeted wt% total solids. The 242-A Evaporator simulant had a layer of solids on the bottom after settling for several days. It appeared that these solids were primarily silicate colloids. The ERDF simulant formed a very significant amount of solids on the bottom of the flask at 30 wt% total solids. This simulant was diluted to 12.3 wt% total solids and there was still a significant layer of solids present on the bottom. These solids were determined by XRD to be gypsum. Because of the amount of solids present and the wt% total solids present in the recent ETF runs of 10-12 wt% due to halide limitations, it was decided to dilute the final ERDF simulant to 10 wt% total solids. This amount of total solids also produced significant undissolved solids. The WTP Off-gas simulant was clear with only a few clear crystals along the container wall present at 18 wt% total solids. However, over time, more crystals appeared to be forming indicating that the solution was at or near saturation. v