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Glass Formulation and Testing with RPP-WTP HLW Simulants (Final Report)

This report presents the results from HLW glass formulation work that was conducted at the Vitreous State Laboratory of The Catholic University of America during Part B1 of the RPP-WTP Project (formally known as TWRS-P) in support of the Privatization contractor, BNFL, Inc. Glass formulation development is required to provide data that are essential for design of the vitrification facility in the near term and for safe and reliable operation of that facility in the longer-term. These data also form the bases from which contractually and technically acceptable immobilized high-level waste (IHLW) products will be devised. Glass formulation therefore impacts many aspects of the vitrification facility design, overall process economics, and contractual compliance. As an integral part of the overall system design, development of glass formulations requires input from many sources including tank waste characterization, pretreatment process definition, flow sheet development, and processing schedules. Accordingly, the glass formulation effort must be responsive to new information as the facility design basis evolves.

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Melter Modeling over a Range of Scales to Support Vitrification at the WTP

Computational modeling is a powerful complement to laboratory experiments and testing of systems at various scales. When properly applied and validated, computational fluid dynamics (CFD) can provide information not readily obtainable by physical testing, especially in cases where the operating environment does not permit visual observation or the insertion of typical data acquisition instrumentation as in the case of waste glass vitrification. A series of CFD and heat transfer models over a range of scales are being developed to support melter operations at the Hanford Waste Treatment and Immobilization Plant. This paper provides a description of the models and the resulting information they provide that can be used to improve melter throughput, as well as aid in evaluating and resolving operating plant issues or upsets. This work is important for the WTP operation by providing a potential for model-predictive control of the melter operation. Increases in the rate of glass production and avoiding idling can significantly decrease the duration and cost of the vitrification campaign, potentially saving billions of dollars.

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Melter Modeling over a Range of Scales to Support Vitrification at the WTP - 19664

Computational modeling is a powerful complement to laboratory experiments and testing of systems at various scales. When properly applied and validated, computational fluid dynamics (CFD) can provide information not readily obtainable by physical testing, especially in cases where the operating environment does not permit visual observation or the insertion of typical data acquisition instrumentation as in the case of waste glass vitrification. A series of CFD and heat transfer models over a range of scales are being developed to support melter operations at the Hanford Waste Treatment and Immobilization Plant. This paper provides a description of the models and the resulting information they provide that can be used to improve melter throughput, as well as aid in evaluating and resolving operating plant issues or upsets. This work is important for the WTP operation by providing a potential for model-predictive control of the melter operation. Increases in the rate of glass production and avoiding idling can significantly decrease the duration and cost of the vitrification campaign, potentially saving billions of dollars. (authors)

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Reduced-Order CFD Modeling to Support Waste Loading Optimization in Hanford WTP Vitrification

The U.S. DOE Hanford Site stores over 56 million gallons of radioactive liquid tank waste that must be treated and immobilized for long-term disposal The Waste Treatment and Immobilization Plant (WTP) will vitrify this waste by feeding it into Joule-heated melters, where it is incorporated into a stable borosilicate glass Computational fluid dynamics (CFD) simulations of glass melters can provide insight into the maximum achievable waste loading under varying melter operating conditions Fully resolved VOF multiphase simulations were used as the reference model to capture bubble-driven convection in the melter, including bubble formation, rise behavior, and induced glass melt circulation Effective bubble column diameter and rise velocity were extracted from the resolved simulations, compared with empirical correlations, and refit across relevant viscosity and gas flow rate conditions Explicit gas–liquid interface tracking was replaced with a single-phase momentum source term model, enabling faster steady-state CFD simulations while preserving the dominant hydrodynamic effects of bubbling New empirical correlations were developed for effective bubble column diameter and bubble rise velocity by fitting resolved simulation data across expected melter viscosity and gas flow rate ranges, providing improved inputs for the momentum source term model compared with existing literature correlations The momentum source term model reduced fluid-domain mesh size by 89% and achieved an 8.4× computational speedup relative to resolved bubbling simulations The validated momentum source term approach enables prediction of process-relevant heat transfer behavior in the integrated melter model, including heat transfer from the molten glass to the cold cap, plenum, refractory walls, and surrounding structural regions under varying melter operating conditions

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WTP Pretreatment Facility Potential Design Deficiencies--Sliding Bed and Sliding Bed Erosion Assessment

This assessment is based on readily available literature and discusses both Newtonian and non-Newtonian slurries with respect to sliding beds and erosion due to sliding beds. This report does not quantify the size of the sliding beds or erosion rates due to sliding beds, but only assesses if they could be present. This assessment addresses process pipelines in the Pretreatment (PT) facility and the high level waste (HLW) transfer lines leaving the PT facility to the HLW vitrification facility concentrate receipt vessel.

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WTP Waste Feed Qualification: Hydrogen Generation Rate Measurement Apparatus Testing Report

The generation rate of hydrogen gas in the Hanford tank waste will be measured during the qualification of the staged tank waste for processing in the Hanford Tank Waste Treatment and Immobilization Plant. Based on a review of past practices in measurement of the hydrogen generation, an apparatus to perform this measurement has been designed and tested for use during waste feed qualification. The hydrogen generation rate measurement apparatus (HGRMA) described in this document utilized a 100 milliliter sample in a continuously-purged, continuously-stirred vessel, with measurement of hydrogen concentration in the vent gas. The vessel and lid had a combined 220 milliliters of headspace. The vent gas system included a small condenser to prevent excessive evaporative losses from the sample during the test, as well as a demister and filter to prevent particle migration from the sample to the gas chromatography system. The gas chromatograph was an on line automated instrument with a large-volume sample-injection system to allow measurement of very low hydrogen concentrations. This instrument automatically sampled the vent gas from the hydrogen generation rate measurement apparatus every five minutes and performed data regression in real time. The fabrication of the hydrogen generation rate measurement apparatus was in accordance with twenty three (23) design requirements documented in the conceptual design package, as well as seven (7) required developmental activities documented in the task plan associated with this work scope. The HGRMA was initially tested for proof of concept with physical simulants, and a remote demonstration of the system was performed in the Savannah River National Laboratory Shielded Cells Mockup Facility. Final verification testing was performed using non-radioactive simulants of the Hanford tank waste. Three different simulants were tested to bound the expected rheological properties expected during waste feed qualification testing. These simulants were tested at different temperatures using purge gas spiked with varying amounts of hydrogen to provide verification that the system could accurately measure the hydrogen in the vent gas at steady state.

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Examples of Disposition Alternatives for WTP Solid Secondary Waste

The Hanford Waste Treatment and Immobilization Plant is planned to produce a variety of solid secondary wastes that will require disposal at the Integrated Disposal Facility on the Hanford Site. Solid secondary wastes include a variety of waste streams that are a result of waste treatment and processing activities.

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Ammonia Remediation in Hanford WTP Liquid Secondary Waste

This report describes the results of work and testing specified by the referenced WRPS approved Test Plans. The work and any associated testing followed established quality assurance requirements and was conducted as authorized. The descriptions provided in this test report are an accurate account of both the conduct of the work and the data collected. Results required by the Test Plan are reported. Also reported are any unusual or anomalous occurrences that are different from the starting hypotheses. The test results and this report have been reviewed and verified.

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Crystallization Constraints for WTP LAW Operations: Assessment of CCC Impacts on VHT and PCT

Much work has been done to expand the glass composition region available for operation of the Hanford Waste Treatment and Immobilization Plant. This includes the development of updated glass property-composition models as well as constraints. This report supports this effort by suggesting constraints for avoiding excessive, and likely detrimental, crystallization during slow cooling of the low-activity glass waste forms in their containers. The constraints target crystals in the Na-Al-silicate and Na-Ca-silicate families. These types of crystals were found to be potentially detrimental to glass durability as they remove Al and Si from the glass matrix, resulting in poor performance of the residual glass during testing such as the Product Consistency Test and the Vapor Hydration Test. Using previously acquired results and results from testing during this effort, the constraints described in the report were determined, and are suggested as options to reduce the risk of forming crystals of the types and concentrations that are likely detrimental to glass durability.

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Glass Crystallization Constraints for WTP LAW Operations: Assessment of Isothermal Treatments on Crystal Formation

Much work has been done to expand the glass composition region available for operation of the Hanford Waste Treatment and Immobilization Plant. This includes the development of updated glass property-composition models as well as constraints. This report supports this effort by suggesting constraints for avoiding excessive, and likely detrimental, crystallization during melter operation while processing advanced low-activity glass waste forms. The constraints target SnO 2 and ZrO 2 crystals that can form when melter temperatures drop below 1100 °C. These types of crystals were found to be potentially detrimental during processing as they are denser than low-activity waste glass melts. SnO 2 , density of 6.95 g/cm3, and ZrO 2 , density of 5.68 g/cm3, have the potential to form during melter idling and settle to the bottom of the less dense glass melt (approximate density 2.65 g/cm3). If the crystals are present in appreciable amounts, they can result in blockages of the pour-spout riser, which impacts glass pouring and melter operation. Using previously acquired results and results from testing during this effort, constraints were determined and are suggested as options to reduce the risk of forming crystals of the types and concentrations that are likely detrimental to melter operation.

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Glass Crystallization Constraints for WTP LAW Operations: Assessment of Isothermal Treatments on Crystal Formation

Much work has been done to expand the glass composition region available for operation of the Hanford Tank Waste Treatment and Immobilization Plant. This includes the development of updated glass property-composition models as well as constraints. This report supports this effort by suggesting constraints for avoiding excessive, and likely detrimental, crystallization during melter operation while processing advanced low-activity glasses. The constraints target Cassiterite and ZrO 2 -containing phases (ZCP, e.g., Baddeleyite and Zircon) that can form when melter temperatures drop below 1100 °C. These types of crystals were found to be potentially detrimental during processing as they are denser than low-activity waste glass melts; with densities of 6.95 g/cm 3 for Cassiterite and 5.68 g/cm 3 for Baddeleyite (the most prevalent ZCP). Compared to melt densities of approximately 2.65 g/cm 3 . Thus, they have the potential to form during melter idling and settle to the bottom of the melter or inside the melter. If the crystals are present in appreciable amounts, they can result in blockages of the pour-spout riser, which impacts glass pouring and melter operation. Additionally, SnO 2 and ZrO 2 are added to glass formulations to improve glass durability. Their precipitation from the melt may reduce overall glass durability. Using previously acquired results and results from testing during this effort, the following constraints (Table S.1) were determined and are recommended to reduce the risk of forming crystals of the types and concentrations that are likely detrimental to melter operation.

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Integrated Off-Gas System Tests on the DM1200 Melter with RPP-WTP LAW Sub-Envelope Bl Simulants, VSL-03R3851-1, Rev. 0 (Oct 2003)

The report documents melter and off-gas performance results obtained on the DM1200 melter during processing of LAW Sub-Envelope B1 feed. The principal objectives of the DM1200 melter testing were to demonstrate suitable processing and production rates for LAW B1 feed; characterize the glass product for elemental composition; measure elemental emission rates and decontamination factors (DFs) across the melter and off-gas treatment components; and provide additional data on the performance of the thermal catalytic oxidation and selective catalytic reduction (TCO/SCR) unit efficiency in treating organic emissions. The feed was spiked with organic compounds for part of the testing duration. All data were collected for use in engineering and system design purposes. No sampling and analysis to collect environmental data was performed during these tests.

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Regulatory Testing of WTP HL W Glasses for Compliance with Delisting Requirements, VSL-03R3780-1, Rev. 1

(Part of the data collected for this work and discussed in this report was subject to data quality and bias issues. All the affected tests have subsequently been repeated, as directed by the Waste Treatment Plant Project, and new statistical analyses have been performed on the revised data set. A subsequently-issued report supercedes this report and describes the revised data, together with the revised composition-property models (Kot et al. 2004). The reader should refer to the new report for discussion of the revised data set and composition-property (TCLP cadmium release) models. None of the data for the spike glasses, designed for Case 1 and Case 2 COPCs testing, were affected by this issue.)

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Integrated Off-Gas System Tests on the DM1200 Melter with RPP-WTP LAW Sub-Envelope C1 Simulants (Final Report)

The report documents melter and off-gas performance results obtained on the DM1200 during processing of LAW Sub-Envelope Cl feed. The principal objectives of the DM1200 melter testing were to demonstrate suitable processing and production rates for LAW Cl feed; characterize the glass product for elemental composition, the presence of organic compounds, and TCLP response for metals; and measure destruction and removal efficiencies (DREs) for organic compounds across the melter and off-gas treatment components. The feed was spiked with organic compounds for part of the testing duration. Data were collected for both process engineering needs and to support regulatory activities. The data needed for regulatory support were collected using EPA methods and independent data analyses and data checking were performed.

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2020 Vision for Tank Waste Cleanup (One System Integration) - 12506

The mission of the Department of Energy's Office of River Protection (ORP) is to safely retrieve and treat the 56 million gallons of Hanford's tank waste and close the Tank Farms to protect the Columbia River. The millions of gallons of waste are a by-product of decades of plutonium production. After irradiated fuel rods were taken from the nuclear reactors to the processing facilities at Hanford they were exposed to a series of chemicals designed to dissolve away the rod, which enabled workers to retrieve the plutonium. Once those chemicals were exposed to the fuel rods they became radioactive and extremely hot. They also couldn't be used in this process more than once. Because the chemicals are caustic and extremely hazardous to humans and the environment, underground storage tanks were built to hold these chemicals until a more permanent solution could be found. The Cleanup of Hanford's 56 million gallons of radioactive and chemical waste stored in 177 large underground tanks represents the Department's largest and most complex environmental remediation project. Sixty percent by volume of the nation's high-level radioactive waste is stored in the underground tanks grouped into 18 'tank farms' on Hanford's central plateau. Hanford's mission to safely remove, treat and dispose of this waste includes the construction of a first-of-its-kind Waste Treatment Plant (WTP), ongoing retrieval of waste from single-shell tanks, and building or upgrading the waste feed delivery infrastructure that will deliver the waste to and support operations of the WTP beginning in 2019. Our discussion of the 2020 Vision for Hanford tank waste cleanup will address the significant progress made to date and ongoing activities to manage the operations of the tank farms and WTP as a single system capable of retrieving, delivering, treating and disposing Hanford's tank waste. The initiation of hot operations and subsequent full operations of the WTP are not only dependent upon the successful design and construction of the WTP, but also on appropriately preparing the tank farms and waste feed delivery infrastructure to reliably and consistently deliver waste feed to the WTP for many decades. The key components of the 2020 vision are: all WTP facilities are commissioned, turned-over and operational, achieving the earliest possible hot operations of completed WTP facilities, and supplying low-activity waste (LAW) feed directly to the LAW Facility using in-tank/near tank supplemental treatment technologies. A One System Integrated Project Team (IPT) was recently formed to focus on developing and executing the programs that will be critical to successful waste feed delivery and WTP startup. The team is comprised of members from Bechtel National, Inc. (BNI), Washington River Protection Solutions LLC (WRPS), and DOE-ORP and DOE-WTP. The IPT will combine WTP and WRPS capabilities in a mission-focused model that is clearly defined, empowered and cost efficient. The genesis for this new team and much of the 2020 vision is based on the work of an earlier team that was tasked with identifying the optimum approach to startup, commissioning, and turnover of WTP facilities for operations. This team worked backwards from 2020 - a date when the project will be completed and steady-state operations will be underway - and identified success criteria to achieving safe and efficient operations of the WTP. The team was not constrained by any existing contract work scope, labor, or funding parameters. Several essential strategies were identified to effectively realize the one-system model of integrated feed stream delivery, WTP operations, and product delivery, and to accomplish the team's vision of hot operations beginning in 2016: - Use a phased startup and turnover approach that will allow WTP facilities to be transitioned to an operational state on as short a timeline as credible. - Align Tank Farm (TF) and WTP objectives such that feed can be supplied to the WTP when it is required for hot operations. - Ensure immobilized waste and waste recycle streams can be received by the TF when required to support 2016 production of immobilized low-activity waste (ILAW). - Ensure the required baseline and additional funding is provided beginning in fiscal year 2011. - Modify TF and WTP contracts to adequately address this vision. The 2020 Vision provides a summary of strategies and key actions that optimize the approach to startup, commissioning, and turnover of WTP facilities. This vision focuses on the legally enforceable requirement to achieve the Consent Decree milestones of starting radioactive operations in 2019, and achieving initial WTP operations in 2022. (authors)

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Calcium Phosphate Constraints in HLW Glasses: Phosphate Liquidus Model

About 50 million gallons of high-level mixed waste is currently stored in underground tanks at the United States Department of Energy’s (DOE’s) Hanford site in the State of Washington. The Hanford Tank Waste Treatment and Immobilization Plant (WTP) will provide DOE’s Office of River Protection (ORP) with a means of treating this waste by vitrification for subsequent disposal. The tank waste will be separated into low- and high-activity waste fractions, which will then be vitrified respectively into Immobilized Low Activity Waste (ILAW) and Immobilized High Level Waste (IHLW) products. The ILAW product will be disposed in an engineered facility on the Hanford site while the IHLW product is designed for acceptance into a national geological disposal facility for high-level nuclear waste. The ILAW and IHLW products must meet a variety of requirements before they can be accepted for disposal. Glass property-composition models will be used to control the vitrification process at the WTP to ensure that the glass meets product quality and processability requirements. The quality and the validity ranges of the property-composition models and the supporting database will greatly influence waste treatment operations, including the waste loading that is achievable in the glass for each waste composition. The current baseline models for operation of the WTP were developed under the Bechtel National, Inc. (BNI) WTP contract. These models were based on LAW and HLW glass property data over a range of compositions that was guided primarily by the WTP contract and the set of tanks specified therein. The HLW testing was directed towards waste streams from the then-planned early feed tanks for the WTP (i.e., AZ-101, AZ-102, C-106/AY-102, and C-104/AY-101). These wastes are high in iron (AZ-101, AZ-102, and C-106/AY-102) or thorium (C-104/AY-101). While the baseline models may be adequate for commissioning of the facility and processing of the specified tanks, refinements and extensions or augmentations of these models will be required to process the balance of the tank waste inventory. The overall mission of the WTP will require the immobilization of tank waste compositions that are variously dominated by mixtures of aluminum, chromium, bismuth, iron, phosphorous, zirconium, and sulfur compounds as waste-loading-limiting components. Further, the WTP contract includes minimum waste loading requirements that are generally rather modest while loadings significantly higher than those in the current baseline are likely achievable. In order to achieve these higher waste loadings and to expand the applicable composition regions, new models will be needed to support the optimized operation of the WTP. Since the development of the baseline WTP models, ORP directed a program of work at the Vitreous State Laboratory (VSL) to examine various approaches for optimization of the performance of the WTP, including increasing the waste loadings in the LAW and HLW glass products. That work involved HLW rich in Al, Al+Na, Cr, Bi, S, Zr, Sr, P and Fe, in contrast to old baseline models that were based mostly on HLW tanks that were high in Fe, with one other that was also high in Th. Glass property data collected under the ORP program were compiled and combined with data collected to develop the WTP models. The combined databases have been used to update pre-existing HLW composition models or to develop new models for properties such as Product Consistency Test (PCT) responses, spinel crystallization (one-percent crystal fraction temperature, T 1% ), melt viscosity, melt electrical conductivity, nepheline formation upon slow cooling (i.e., Canister Centerline Cooling [CCC]), and Toxicity Characteristic Leach Procedure (TCLP) Cd response. While spinel is typically the most commonly occurring phase in HLW glasses, other phases can be limiting depending on the waste and glass composition. For example, various phosphate phases can become important as the phosphorus content increases. Lithium phosphate crystallization can impact PCT releases of HLW glasses, while calcium phosphate phases forming in the cold-cap can deleteriously impact feed processing in the melter. At present, however, no models exist that relate glass composition and crystallization of phosphate phases in general and calcium phosphate in particular. The present work was therefore directed towards the initial development of such models. Future work may be directed at studying amorphous phase separation in high phosphate HLW glasses. Within the River Protection Project, feed compositions are projected using the Hanford Tank Waste Operations Simulator (HTWOS), a dynamic computer model that tracks the waste through storage, retrieval, feed staging, and treatment processes. A review of the HTWOS data shows that WTP will process 4106 batches of HLW glass for the overall mission (System Plan Rev. 6, ORP-11242), each with its own waste feed and glass composition. Some of the projected HTWOS feed batches are expected to have relatively high concentrations of phosphorous compared to typical HLW streams. In the 4106 batches of HLW for the overall WTP mission P 2 O 5 varies from 0.59 wt% to 13.00 wt%, with 95 batches containing at least 10 wt% P 2 O 5 . Occurrences of phosphate crystals have commonly been noted in glasses with high bismuth and phosphorus contents. In addition, recently collected data from a set of statistically designed HLW matrix glasses prepared and characterized to support enhancement of the HLW glass property-composition models identified apatite in a number of glass samples. However, the current HLW model for crystallization (one-percent crystal fraction temperature) is applicable only to spinel crystallization in glasses. Previous projections of waste loadings and glass volume (such as those in System Plan Rev. 6, ORP-11242) have used preliminary constraints for calcium phosphate crystallization that are based on the limited available data. Additional data and improved constraints or, preferably, models that relate glass composition to crystallization of phosphate-containing phases, are therefore needed to support HLW vitrification at the WTP. The present study focuses on the development of such a model based on data from previously characterized glasses and a set of newly fabricated glasses.

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