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SB5 WITH THE ESTIMATED IMPACT OF LOW TEMPERATURE ALUMINUM DISSOLUTION: PRELIMINARY FRITS FOR MELT RATE TESTING

Description: Composition projections for Sludge Batch 5 (SB5) were developed to evaluate possible impacts of the Al-dissolution process on the availability of viable frit compositions for vitrification at the DWPF. The study included two projected SB5 compositions that bound potential outcomes (or degrees of effectiveness) of the Al-dissolution process, as well as a nominal SB5 composition projection based on the results of the recent Al-dissolution demonstration at SRNL. A Nominal Stage assessment was used to evaluate the two SB5 projections combined with an array of 19,305 frit compositions over a range of waste loading (WL) values against the DWPF process control models. The Nominal Stage results allowed for the down-selection of a small number of frits that provided reasonable projected operating windows (typically 25 to 40 wt %) and permitted some compositional flexibility (i.e., the ability to further tailor the frit to improve melt rate). Variation Stage assessments were then performed using the down-selected frits and the two SB5 composition projections with variation applied to each sludge component. The Variation Stage results showed that the operating windows were somewhat reduced in width, as expected when sludge variation is applied. Three of the down-selected frits continued to perform well for both SB5 projections through the Variation Stage, providing WL windows of approximately 26 to 35 wt %. The maximum WLs were limited by a processing constraint, TL, rather than a waste form affecting constraint (e.g., nepheline crystallization) in the Variation Stage assessments. Subsequent Nominal Stage assessments were performed with an updated SB5 projection based on the results of the Al-dissolution demonstration performed in the SRNL Shielded Cells facility (representing 40% removal of Al). The three frits identified in the earlier paper studies continued to perform well with this updated projection. The available operating windows were slightly wider, although maximum WL was limited ...
Date: March 11, 2008
Creator: Fox, K & Tommy Edwards, T
Partner: UNT Libraries Government Documents Department

REFINEMENT OF THE NEPHELINE DISCRIMINATOR: RESULTS OF A PHASE II STUDY

Description: Twenty five glass compositions were selected for a Phase II study to assess the potential for reducing the conservatism in the nepheline discriminator. The glass compositions were restricted to regions that fell within the validation ranges of the DWPF PCCS models. In addition, the liquidus temperature model was used to restrict the glass compositions so that they could all be melted at the same temperature. The nepheline discriminator was used to force the glass compositions into regions where nepheline formation was predicted to occur. The glasses were fabricated in the laboratory and characterized for crystallization and chemical durability after both quenching and slow cooling. Chemical analysis showed that the fabricated glasses met the target compositions. Nepheline was identified in one of the quenched glasses and several of the CCC glasses. There was no clear relationship between the types of crystallization that occurred in a particular glass and its location on the Al{sub 2}O{sub 3}-Na{sub 2}O-SiO{sub 2} ternary diagram. A partitioning algorithm was used to identify trends in crystallization behavior based on glass composition. Generally, for the CCC glasses MnO influenced the crystallization of spinels and B{sub 2}O{sub 3} and SiO{sub 2} influenced the crystallization of nepheline. Measured durability responses varied from acceptable to unacceptable depending on the glass composition and type and extent of crystallization that occurred. It was not possible to identify any linear effects of composition on chemical durability performance for this set of study glasses. The results were not sufficient to recommend modification of the current nepheline discriminator at this time. It is recommended that the next series of experiments continue to focus not only on compositional regions where the PCCS models are considered applicable (i.e., the model validation ranges), but also be restricted to compositional regions where acceptable glasses are predicted to be produced but are ...
Date: November 21, 2008
Creator: Fox, K & Tommy Edwards, T
Partner: UNT Libraries Government Documents Department

TIME-TEMPERATURE-TRANSFORMATION DIAGRAMS FOR THE SLUDGE BATCH 3 - FRIT 418 GLASS SYSTEM

Description: As a part of the Waste Acceptance Product Specifications (WAPS) for Vitrified High-Level Waste Forms defined by the Department of Energy - Office of Environmental Management, the phase stability must be determined for each of the projected high-level waste (HLW) types at the Savannah River Site (SRS). Specifically, WAPS 1.4.1 requires the glass transition temperature (Tg) to be defined and time-temperature-transformation (TTT) diagrams to be developed. The Tg of a glass is an indicator of the approximate temperature where the supercooled liquid converts to a solid on cooling or conversely, where the solid begins to behave as a viscoelastic solid on heating. A TTT diagram identifies the crystalline phases that can form as a function of time and temperature for a given waste type or more specifically, the borosilicate glass waste form. In order to assess durability, the Product Consistency Test (PCT) was used and the durability results compared to the Environmental Assessment (EA) glass. The measurement of glass transition temperature and the development of TTT diagrams have already been performed for the seven Defense Waste Processing Facility (DWPF) projected compositions as defined in the Waste Form Compliance Plan (WCP). These measurements were performed before DWPF start-up and the results were incorporated in Volume 7 of the Waste Form Qualification Report (WQR). Additional information exists for other projected compositions, but overall these compositions did not consider some of the processing scenarios now envisioned for DWPF to accelerate throughput. Changes in DWPF processing strategy have required this WAPS specification to be revisited to ensure that the resulting phases have been bounded. Frit 418 was primarily used to process HLW Sludge Batch 3 (SB3) at 38% waste loading (WL) through the DWPF. The Savannah River National Laboratory (SRNL) fabricated a cache of glass from reagent grade oxides to simulate the SB3-Frit 418 ...
Date: March 3, 2009
Creator: Billings, A & Tommy Edwards, T
Partner: UNT Libraries Government Documents Department

RECENT STUDIES OF URANIUM AND PLUTONIUM CHEMISTRY IN ALKALINE RADIOACTIVE WASTE SOLUTIONS

Description: Solubility studies of uranium and plutonium in a caustic, radioactive Savannah River Site tank waste solution revealed the existence of uranium supersaturation in the as-received sample. Comparison of the results to predictions generated from previously published models for solubility in these waste types revealed that the U model poorly predicts solubility while Pu model predictions are quite consistent with experimental observations. Separate studies using simulated Savannah River Site evaporator feed solution revealed that the known formation of sodium aluminosilicate solids in waste evaporators can promote rapid precipitation of uranium from supersaturated solutions.
Date: June 13, 2006
Creator: King, W; Bill Wilmarth, B; David Hobbs, D & Tommy Edwards, T
Partner: UNT Libraries Government Documents Department

TECHNOLOGY DEMONSTRATION OF SLUDGE MASS REDUCTION VIA ALUMINUM DISSOLUTION: GLASS FORMULATION PROCESSING WINDOW PREDICTIONS FOR SB5

Description: Composition projections for Sludge Batch 5 (SB5) were developed, based on a modeling approach at the Savannah River National Laboratory (SRNL), to evaluate possible impacts of the Al-dissolution process on the availability of viable frit compositions for vitrification at the Defense Waste Processing Facility (DWPF). The study included two projected SB5 compositions that bound potential outcomes (or degrees of effectiveness) of the Al-dissolution process, as well as a nominal SB5 composition projection based on the results of the recent Al-dissolution demonstration at SRNL. The three SB5 projections were the focus of a two-stage paper study assessment. A Nominal Stage assessment combined each of the SB5 composition projections with an array of 19,305 frit compositions over a wide range of waste loading (WL) values and evaluated them against the DWPF process control models. The Nominal Stage results allowed for the down-selection of a small number of frits that provided reasonable projected operating windows (typically 27 to 42 wt% WL). The frit/sludge systems were mostly limited by process related constraints, with only one system being limited by predictions of nepheline crystallization, a waste form affecting constraint. The criteria applied in selecting the frit compositions somewhat restricted the compositional flexibility of the candidate frits for each individual SB5 composition projection, which may limit the ability to further tailor the frit for improved melt rate. Variation Stage assessments were then performed using the down-selected frits and the three SB5 composition projections with variation applied to each sludge component. The Variation Stage results showed that the operating windows were reduced in width, as expected when variation in the sludge composition is applied. However, several of the down-selected frits exhibited a relatively high degree of robustness to the applied sludge variation, providing WL windows of approximately 30 to 39 wt%. The maximum WLs were limited by ...
Date: December 28, 2007
Creator: Fox, K; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

SULFATE RETENTION IN HIGH LEVEL WASTE SLUDGE BATCH 4 GLASSES: A PRELIMINARY ASSESSMENT

Description: Early projections of the Sludge Batch 4 (SB4) composition predicted relatively high concentrations of alumina (Al{sub 2}O{sub 3}, 23.5 wt%) and sulfate (SO{sub 4}{sup 2-}, 1.2 wt%) in the sludge. A high concentration of Al{sub 2}O{sub 3} in the sludge, combined with Na{sub 2}O additions in the frit, raises the potential for nepheline crystallization in the glass. However, strategic frit development efforts at the Savannah River National Laboratory (SRNL) have shown that frits containing a relatively high concentration of B{sub 2}O{sub 3} can both suppress nepheline crystallization and improve melt rates. A high sulfate concentration is a concern to the DWPF as it can lead to the formation of sulfate inclusions in the glass and/or the formation of a molten, sulfate-rich phase atop the melt pool. To avoid these issues, a sulfate concentration limit of 0.4 wt% SO{sub 4}{sup 2-} in glass was originally set in the Product Composition Control System (PCCS) used at DWPF. It was later shown that this limit could be increased to 0.6 wt% SO{sub 4}{sup 2-} in glass for the Frit 418, Sludge Batch 3 (SB3) system.
Date: December 11, 2006
Creator: Fox, K; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

GLASS SELECTION STRATEGY: DEVELOPMENT OF US AND KRI TEST MATRICIES

Description: High-level radioactive wastes are stored as liquids in underground storage tanks at the Department of Energy's (DOE) Savannah River Site (SRS) and Hanford Reservation. These wastes are to be prepared for permanent disposition in a geologic repository by vitrification with glass forming additives (e.g., frit), creating a waste form with long-term durability. Wastes at SRS are being vitrified in the Defense Waste Processing Facility (DWPF). Vitrification of the wastes stored at Hanford is planned for the Waste Treatment and Immobilization Plant (WTP) when completed. Some of the wastes at SRS, and particularly those at Hanford, contain high concentrations of aluminum, chromium and sulfate. These elements make it more difficult to produce a waste glass with a high waste loading (WL) without crystallization occurring in the glass (either within the melter or upon cooling of the glass), potentially exceeding the solubility limit of critical components, having negative impacts on durability, and/or resulting in the formation of a sulfate salt layer on the molten glass surface. Although the overall scope of the task is focused on all three critical, chemical components, the current work will primarily address the potential for crystallization (e.g., nepheline and/or spinel) in high level waste (HLW) glasses. Recent work at the Savannah River National Laboratory (SRNL) and by other groups has shown that nepheline (NaAlSiO{sub 4}), which is likely to crystallize in high-alumina glasses, has a detrimental effect on the durability of the glass. The objective of this task is to develop glass formulations for specific SRS and Hanford waste streams to avoid nepheline formation while meeting waste loading and waste throughput expectations, as well as satisfying critical process and product performance related constraints. Secondary objectives of this task are to assess the sulfate solubility limit for the DWPF composition and spinel settling for the WTP composition. SRNL ...
Date: February 6, 2007
Creator: Fox, K; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

SENSITIVITY ANALYSIS OF A TPB DEGRADATION RATE MODEL

Description: A tetraphenylborate (TPB) degradation model for use in aggregating Tank 48 material in Tank 50 is developed in this report. The influential factors for this model are listed as the headings in the table below. A sensitivity study of the predictions of the model over intervals of values for the influential factors affecting the model was conducted. These intervals bound the levels of these factors expected during Tank 50 aggregations. The results from the sensitivity analysis were used to identify settings for the influential factors that yielded the largest predicted TPB degradation rate. Thus, these factor settings are considered as those that yield the ''worst-case'' scenario for TPB degradation rate for Tank 50 aggregation, and, as such they would define the test conditions that should be studied in a waste qualification program whose dual purpose would be the investigation of the introduction of Tank 48 material for aggregation in Tank 50 and the bounding of TPB degradation rates for such aggregations.
Date: August 1, 2006
Creator: Crawford, C; Tommy Edwards, T & Bill Wilmarth, B
Partner: UNT Libraries Government Documents Department

DEFINING A GLASS COMPOSITION ENVELOPE FOR AN IMPURITY VARIABILITY STUDY TO SUPPORT PLUTONIUM DISPOSITION

Description: This study focuses on the development of a composition envelope that describes the solubility of various impurities in the lanthanide borosilicate (LaBS) glass. A series of glass compositions was selected, fabricated and characterized in order to define this envelope. The selection of glass compositions, which is the focus of this report, was based on the projected types and concentrations of impurities expected in the plutonium feed stream. A limited amount of impurity data for the various plutonium sources is available and projections were made through analysis of the available information. These projections were used to define the glass compositions to be fabricated and tested. The results of this glass selection process provided an array of glass compositions to be fabricated and characterized in the laboratory in order to evaluate the solubility of various impurity elements and their effects on crystallization and durability as measured by the Product Consistency Test (PCT). The majority of the glasses will be formulated with hafnium as a surrogate for plutonium to simplify laboratory experiments. Plutonium glass testing will also be implemented for select compositions to validate the results of the surrogate testing. The results of this variability testing will be discussed in a separate report that will provide data to validate the acceptability of the compositional envelope defined here and/or provide additional compositional constraints for the plutonium feed materials.
Date: August 21, 2007
Creator: Fox, K; Elizabeth Hoffman, E; Tommy Edwards, T & James Marra, J
Partner: UNT Libraries Government Documents Department

HEAT OF HYDRATION OF SALTSTONE MIXES-MEASUREMENT BY ISOTHERMAL CALORIMETRY

Description: This report provides initial results on the measurement of heat of hydration of Saltstone mixes using isothermal calorimetry. The results were obtained using a recently purchased TAM Air Model 3116 Isothermal Conduction Calorimeter. Heat of hydration is an important property of Saltstone mixes. Greater amounts of heat will increase the temperature of the curing mix in the vaults and limit the processing rate. The heat of hydration also reflects the extent of the hydraulic reactions that turn the fluid mixture into a ''stone like'' solid and consequently impacts performance properties such as permeability. Determining which factors control these reactions, as monitored by the heat of hydration, is an important goal of the variability study. Experiments with mixes of portland cement in water demonstrated that the heats measured by this technique over a seven day period match very well with the literature values of (1) seven day heats of hydration using the standard test method for heat of hydration of hydraulic cement, ASTM C 186-05 and (2) heats of hydration measured using isothermal calorimetry. The heats of hydration of portland cement or blast furnace slag in a Modular Caustic Side Solvent Extraction Unit (MCU) simulant revealed that if the cure temperature is maintained at 25 C, the amount of heat released over a seven day period is roughly 62% less than the heat released by portland cement in water. Furthermore, both the blast furnace slag and the portland cement were found to be equivalent in heat production over the seven day period in MCU. This equivalency is due to the activation of the slag by the greater than 1 Molar free hydroxide ion concentration in the simulant. Results using premix (a blend of 10% cement, 45% blast furnace slag, and 45% fly ash) in MCU, Deliquification, Dissolution and Adjustment (DDA) and ...
Date: July 2, 2007
Creator: Harbour, J; Vickie Williams, V & Tommy Edwards, T
Partner: UNT Libraries Government Documents Department

HIGH LEVEL WASTE (HLW) SLUDGE BATCH 4 (SB4): SELECTING GLASSES FOR A VARIABILITY STUDY

Description: A critical step in the Sludge Batch 4 (SB4) qualification process is to demonstrate the applicability of the durability models, which are used as part of the Defense Waste Processing Facility's (DWPF's) process control strategy, to the frit / SB4 glass system via a variability study. A variability study is an experimentally-driven assessment of the predictability and acceptability of the vitrified waste product quality that is anticipated from the processing of a sludge batch. The quality of the waste form is a measure of its durability as determined by the Product Consistency Test (PCT). At the DWPF, the durability of the vitrified waste product is not directly measured by this test during normal operation. Instead, the durability is predicted using a set of models that relate the PCT response of a glass to the chemical composition of that glass. The main objective of a variability study is to demonstrate that these models are applicable to the glass composition region anticipated during the processing of the sludge batch. The success of this demonstration allows the DWPF to confidently rely on the predictions of the durability/composition models as they are used in the control of the DWPF process. The glass region for the SB4 variability study was determined using the most recent projections of the compositions of this sludge batch. Variation was introduced into the composition of the sludge to account for the uncertainty present in these projections as well as for process variation that may be experienced at the DWPF during its normal operations. The primary focus will be on the use of Frit 503, as this frit was recommended for SB4 processing. However, the frit recommendation memorandum also stated that Frit 418 is a viable option, especially for DWPF processing during the transition from SB3 to SB4 (i.e., an acceptable ...
Date: August 17, 2006
Creator: Fox, K; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

SLUDGE BATCH 4: MODEL BASED ASSESSMENTS OF THE FEBRUARY 2007 SLUDGE PROJECTION

Description: The Savannah River National Laboratory (SRNL) has developed, and continues to enhance, its integrated capability to evaluate the impact of proposed sludge preparation plans on the Defense Waste Processing Facility's (DWPF's) operation. One of the components of this integrated capability focuses on frit development which identifies a viable frit or frits for each sludge option being contemplated for DWPF processing. A frit is considered viable if its composition allows for economic fabrication and if, when it is combined with the sludge option under consideration, the DWPF property/composition models (the models of DWPF's Product Composition Control System (PCCS)) indicate that the combination has the potential for an operating window (a waste loading (WL) interval over which the sludge/frit glass system satisfies processability and durability constraints) that would allow DWPF to meet its goals for waste loading and canister production. This report documents the results of SRNL's efforts to identify candidate frit compositions and corresponding predicted operating windows (defined in terms of WL intervals) for the February 2007 compositional projection of Sludge Batch 4 (SB4) developed by the Liquid Waste Organization (LWO). The nominal compositional projection was used to assess projected operating windows (in terms of a waste loading interval over which all predicted properties were classified as acceptable) for various frits, evaluate the applicability of the 0.6 wt% SO{sub 4}{sup =} PCCS limit to the glass systems of interest, and determine the impact (or lack thereof) to the previous SB4 variability studies. It should be mentioned that the information from this report will be coupled with assessments of melt rate to recommend a frit for SB4 processing. The results of this paper study suggest that candidate frits are available to process the nominal SB4 composition over attractive waste loadings of interest to DWPF. Specifically, two primary candidate frits for SB4 processing, ...
Date: March 22, 2007
Creator: Peeler, D; Tommy Edwards, T & Kevin Fox, K
Partner: UNT Libraries Government Documents Department

SLUDGE BATCH 4 (SB4) AFTER A TANK 40 DECANT: CANDIDATE FRITS, MAR ASSESSMENTS, AND GLASSES FOR A VARIABILITY STUDY

Description: In early October 2006, the Liquid Waste Organization (LWO) began to consider decanting Tank 40 at the end of Sludge Batch 3 (SB3) processing and transferring the aqueous phase from the decant to Tank 51. This transfer would be done to decrease Tank 51 yield stress and facilitate the transfer of the contents of Tank 51 to Tank 40. The projected composition of Sludge Batch 4 (SB4) was adjusted by LWO to reflect the impact of the Tank 40 decant leading to new projected compositions for SB4, designated as the 10-04-06 and the 10-10-06 compositions. A comparison between these SB4 compositions and those provided in June 2006 indicates that the new compositions are slightly higher in Al2O3, Fe2O3, and U3O8 and slightly lower in SiO2. The most dramatic change, however, is the new projection's Na2O concentration, which is more than 4.5 wt% lower than the June 2006 projection. This is a significant change due to the frit development team's approach of aligning the Na2O concentration in a candidate frit to the Na2O content of the sludge. This approach enhances the projected operating window and the waste throughput potential for the resulting glass system while eliminating the potential for nepheline crystallization. Nepheline can have a detrimental impact on durability. Questions surfaced regarding the applicability of Frit 503 to these revised compositions since the Savannah River National Laboratory (SRNL) recommended Frit 503 for use with SB4 based on the June 2006 compositional projection without the Tank 40 decant. Based on the paper study assessments, the change in SB4's expected Na2O content had a significant, negative impact on the projected operating window for the Frit 503/SB4 glass system. While Frit 418 had slightly smaller waste loading (WL) intervals for the June 2006 SB4 projections as compared to Frit 503 and the Frit 418 ...
Date: November 30, 2006
Creator: Fox, K; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

FRIT SELECTION TO SUPPORT STEKLO METALLICHESKIE KONSTRUKTSII MELTER TESTING WITH SRNL FEEDS

Description: Four frits were developed for possible use in melter testing with V.G. Khlopin Radium Institute's Steklo Metallicheskie Konstruktsii (SMK) melter. The frits were selected using Measurement Acceptability Region (MAR) assessments of an array of frit formulations and two Sludge Batch 5 (SB5) flowsheets, one with the anticipated effect of the implementation of Al-dissolution and one without. Test glasses were fabricated in the laboratory to verify that the property and performance models used to select the frits were applicable to the frit/sludge systems of interest. Each of the four frits was tested with each of the two sludges at two different waste loadings, for a total of 16 test glasses. Each glass was both quenched and subjected to the canister centerline cooled (CCC) thermal profile. Samples of each glass were examined for crystallization by X-ray diffraction (XRD) and durability using the Product Consistency Test (PCT). The quenched version of each glass appeared amorphous by visual observations, although XRD results indicated a small amount of crystallization in four of the quenched glasses. Visual observations identified surface crystallization on the CCC versions of all 16 glasses. Three of the 35% waste loading (WL), CCC glasses were found to contain trevorite (a spinel) by XRD, and all of the 40% WL CCC glasses were found to contain trevorite. Nepheline was not observed in any of the test glasses, which is consistent with model predictions.
Date: July 26, 2007
Creator: Fox, K; James Gillam, J; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

INITIAL MAR ASSESSMENTS TO ACCESS THE IMPACT OF AL DISSOLUTION ON DWPF OPERATING WINDOWS

Description: SRNL was tasked to provide an assessment of the downstream impacts (or lack thereof) to DWPF of decisions regarding the implementation of Al-dissolution to support sludge mass reduction and processing. Based on future sludge batch compositional projections, assessments have been made with respect to the ability to maintain comparable projected operating windows for sludges with high temperature Al-dissolution and without Al-dissolution. In general, paper study assessments indicated that most of the future sludge batches (twelve with and fourteen without high temperature Al-dissolution) had multiple frits available that yielded relatively large operating windows. The projected operating windows were defined by the waste loading (WL) interval over which glasses were classified as acceptable based on current process control models and their related constraints. Although multiple frits were identified, using a 17-point width as a general guide for a reasonable operating window (e.g., 25-41% WL), there generally appeared to be more flexibility in frit selection for the without Al-dissolution flowsheets. This larger frit compositional platform could allow frit development efforts to make more significant adjustments to melt rate. However, based on the general observations of the paper study, there is essentially no clear distinction between the two options with which to drive a decision to implement Al-dissolution. That is, comparable operating windows can be achieved through the frit development and selection process for either process. One could interpret this general summary statement to indicate: given frit development efforts can compensate for the different pretreatment strategies yielding equivalent operating windows or maximum WL targets, the lower sludge mass as a result of Al-dissolution would obviously result in reducing the number of cans produced at DWPF. Although the basic mathematics is technically sound, other factors need to be considered including facility operating times or mission life for the Tank Farm, DWPF and Saltstone. To address ...
Date: February 5, 2008
Creator: Newell, J; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

IMPACT OF INCREASED ALUMINATE CONCENTRATIONS ON PROPERTIES OF SALTSTONE MIXES

Description: One of the goals of the Saltstone variability study is to identify the operational and compositional variables that control or influence the important processing and performance properties of Saltstone mixes. The protocols developed in this variability study are ideally suited as a tool to assess the impact of proposed changes to the processing flow sheet for Liquid Waste Operations (LWO). One such proposal that is currently under consideration is to introduce a leaching step in the treatment of the High Level Waste (HLW) sludge to remove aluminum prior to vitrification at the Defense Waste Processing Facility (DWPF). This leachate would significantly increase the soluble aluminate concentrations as well as the free hydroxide ion concentration in the salt feed that will be processed at the Saltstone Processing Facility (SPF). Consequently, an initial study of the impact of increased aluminate concentration on the Saltstone grout properties was performed. The projected compositions and ranges of the aluminate rich salt stream (which includes the blending strategy) are not yet available and consequently, in this initial report, two separate salt stream compositions were investigated. The first stream starts with the previously projected baseline composition of the salt solution that will be fed to SPF from the Salt Waste Processing Facility (SWPF). The second stream is the solution that results from washing of the current Tank 51 sludge and subsequent transfer of the salt solution to Tank 11. The SWPF simulant has higher nitrate and lower free hydroxide than the Tank 11 simulant. In both of these cases, the aluminate was varied up to a maximum of 0.40 to 0.45M aluminate in order to evaluate the impact of increasing aluminate ion concentration on the grout properties. In general, the fresh grout properties of mixes made with SWPF and Tank 11 simulants were relatively insensitive to an ...
Date: October 12, 2007
Creator: Harbour, J; Tommy Edwards, T; Erich Hansen, E & Vickie Williams, V
Partner: UNT Libraries Government Documents Department

IMPACT OF NOBLE METALS AND MERCURY ON HYDROGEN GENERATION DURING HIGH LEVEL WASTE PRETREATMENT AT THE SAVANNAH RIVER SITE

Description: The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies radioactive High Level Waste (HLW) for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. HLW consists of insoluble metal hydroxides (primarily iron, aluminum, calcium, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, and sulfate). The pretreatment process in the Chemical Processing Cell (CPC) consists of two process tanks, the Sludge Receipt and Adjustment Tank (SRAT) and the Slurry Mix Evaporator (SME) as well as a melter feed tank. During SRAT processing, nitric and formic acids are added to the sludge to lower pH, destroy nitrite and carbonate ions, and reduce mercury and manganese. During the SME cycle, glass formers are added, and the batch is concentrated to the final solids target prior to vitrification. During these processes, hydrogen can be produced by catalytic decomposition of excess formic acid. The waste contains silver, palladium, rhodium, ruthenium, and mercury, but silver and palladium have been shown to be insignificant factors in catalytic hydrogen generation during the DWPF process. A full factorial experimental design was developed to ensure that the existence of statistically significant two-way interactions could be determined without confounding of the main effects with the two-way interaction effects. Rh ranged from 0.0026-0.013% and Ru ranged from 0.010-0.050% in the dried sludge solids, while initial Hg ranged from 0.5-2.5 wt%, as shown in Table 1. The nominal matrix design consisted of twelve SRAT cycles. Testing included: a three factor (Rh, Ru, and Hg) study at two levels per factor (eight runs), three duplicate midpoint runs, and one additional replicate run to assess reproducibility away from the midpoint. Midpoint testing was used to identify potential quadratic effects from the three factors. A single sludge simulant was used for all tests ...
Date: March 3, 2009
Creator: Stone, M; Tommy Edwards, T & David Koopman, D
Partner: UNT Libraries Government Documents Department

THE IMPACT OF A TANK 40H DECANT ON THE PROJECTED OPERATING WINDOWS FOR SB4 AND GLASS SELECTION STRATEGY IN SUPPORT OF THE VARIABILITY STUDY

Description: The Liquid Waste Organization (LWO) has requested that the Savannah River National Laboratory (SRNL) to assess the impact of a 100K gallon decant volume from Tank 40H on the existing sludge-only Sludge Batch 4 (SB4)-Frit 510 flowsheet and the coupled operations flowsheet (SB4 with the Actinide Removal Process (ARP)). Another potential SB4 flowsheet modification of interest includes the addition of 3 wt% sodium (on a calcined oxide basis) to a decanted sludge-only or coupled operations flowsheet. These potential SB4 flowsheet modifications could result in significant compositional shifts to the SB4 system. This paper study provides an assessment of the impact of these compositional changes to the projected glass operating windows and to the variability study for the Frit 510-SB4 system. The influence of the compositional changes on melt rate was not assessed in this study nor was it requested. Nominal Stage paper study assessments were completed using the projected compositions for the various flowsheet options coupled with Frit 510 (i.e., variation was not applied to the sludge and frit compositions). In order to gain insight into the impacts of sludge variation and/or frit variation (due to the procurement specifications) on the projected operating windows, three versions of the Variation Stage assessment were performed: (1) the traditional Variation Stage assessment in which the nominal Frit 510 composition was coupled with the extreme vertices (EVs) of each sludge, (2) an assessment of the impact of possible frit variation (within the accepted frit specification tolerances) on each nominal SB4 option, and (3) an assessment of the impact of possible variation in the Frit 510 composition due to the vendor's acceptance specifications coupled with the EVs of each sludge case. The results of the Nominal Stage assessment indicate very little difference among the various flowsheet options. All of the flowsheets provide DWPF with the ...
Date: February 7, 2008
Creator: Raszewski, F; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

IMPACT OF ALUMINATE IONS ON THE PROPERTIES OF SALTSTONE GROUT MIXES

Description: It is important to identify and control the operational and compositional variables that impact the important processing and performance properties of Saltstone grout mixes. The grout that is produced at the Saltstone Production Facility (SPF) is referred to as Saltstone and is a waste form that immobilizes low concentrations of radionuclides as well as certain toxic metals. The Saltstone will be disposed of in vaults at Savannah River Site (SRS). An effort referred to as the Saltstone Variability Study has been initiated to achieve this goal. The protocols developed in this variability study are also ideally suited as a tool to assess the impact of proposed changes to the processing flow sheet for Liquid Waste Operations at SRS. One such proposal that is currently under consideration is to introduce a leaching step in the treatment of the High Level Waste (HLW) sludge to remove aluminum prior to vitrification at the Defense Waste Processing Facility (DWPF). This leachate would significantly increase the soluble aluminate concentration in the salt feed that will be processed at the SPF. Consequently, an initial study of the impact of increased aluminate concentration on the Saltstone grout properties was performed. Prior work by Lukens (1) showed that aluminate in the salt solutions increases the amount of heat generation.
Date: February 21, 2008
Creator: Harbour, J; Tommy Edwards, T; Erich Hansen, E & Vickie Williams, V
Partner: UNT Libraries Government Documents Department

RECOMMENDED FRIT COMPOSITION FOR INITIAL SLUDGE BATCH 5 PROCESSING AT THE DEFENSE WASTE PROCESSING FACILITY

Description: The Savannah River National Laboratory (SRNL) Frit Development Team recommends that the Defense Waste Processing Facility (DWPF) utilize Frit 418 for initial processing of high level waste (HLW) Sludge Batch 5 (SB5). The extended SB5 preparation time and need for DWPF feed have necessitated the use of a frit that is already included on the DWPF procurement specification. Frit 418 has been used previously in vitrification of Sludge Batches 3 and 4. Paper study assessments predict that Frit 418 will form an acceptable glass when combined with SB5 over a range of waste loadings (WLs), typically 30-41% based on nominal projected SB5 compositions. Frit 418 has a relatively high degree of robustness with regard to variation in the projected SB5 composition, particularly when the Na{sub 2}O concentration is varied. The acceptability (chemical durability) and model applicability of the Frit 418-SB5 system will be verified experimentally through a variability study, to be documented separately. Frit 418 has not been designed to provide an optimal melt rate with SB5, but is recommended for initial processing of SB5 until experimental testing to optimize a frit composition for melt rate can be completed. Melt rate performance can not be predicted at this time and must be determined experimentally. Note that melt rate testing may either identify an improved frit for SB5 processing (one which produces an acceptable glass at a faster rate than Frit 418) or confirm that Frit 418 is the best option.
Date: June 25, 2008
Creator: Fox, K; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

SLUDGE BATCH 5 VARIABILITY STUDY WITH FRIT 418

Description: The Defense Waste Processing Facility (DWPF) is preparing to initiate processing Sludge Batch 5 (SB5) in early FY 2009. In support of the upcoming processing, the Savannah River National Laboratory (SRNL) provided a recommendation to utilize Frit 418 as a transitional frit to initiate processing of SB5. This recommendation was based on the results of assessments on the compositional projections for SB5 available at that time from both the Liquid Waste Organization (LWO) and SRNL (using a model-based approach). To support qualification of the Frit 418-SB5 system, SRNL executed a variability study to assess the acceptability of the Frit 418-SB5 glasses with respect to durability and the applicability of the current durability models. Twenty one glasses were selected for the variability study based on the available SB5 projections primarily spanning a waste loading (WL) range of 25-37%. In order to account for the addition of caustic to Tank 40, which occurred in July 2008, 3 wt% Na2O was added to the original Tank 40 heel projections. The addition of the Actinide Removal Process (ARP) stream to the blend composition was also included. Two of the glasses were fabricated at 25% and 28% WL in order to challenge the homogeneity constraint of the Product Composition Control System (PCCS) for SB5 coupled operations. These twenty one glasses were fabricated and characterized using chemical composition analysis, X-ray Diffraction (XRD) and the Product Consistency Test (PCT). The results of this study indicate that Frit 418 is a viable option for sludge-only and coupled operations. The addition of ARP did not have any negative impacts on the acceptability and predictability of the variability study glasses. Based on the measured PCT response, all of the glasses were acceptable as compared to the Environmental Assessment (EA) reference glass regardless of the thermal history and were also predictable ...
Date: September 29, 2008
Creator: Raszewski, F; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

MATRIX 1 RESULTS OF THE FY07 ENHANCED DOE HIGH-LEVEL WASTE MELTER THROUGHPUT STUDIES AT SRNL

Description: High-level waste (HLW) throughput (i.e., the amount of waste processed per unit time) is a function of two critical parameters: waste loading (WL) and melt rate. For the Waste Treatment and Immobilization Plant (WTP) at the Hanford Site and the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS), increasing HLW throughput would significantly reduce the overall mission life cycle costs for the Department of Energy (DOE). It has been proposed that a team of glass formulation and processing experts at the Pacific Northwest National Laboratory (PNNL), Savannah River National Laboratory (SRNL), and Vitreous State Laboratory (VSL) at Catholic University of America develop a systematic approach to increase HLW throughput (by increasing WL with minimal or positive impacts on melt rate). Programmatically, this task is aimed at proof-of-principle testing and the development of tools to improve waste loading and melt rate, which will lead to higher waste throughput. The following four specific tasks have been proposed to meet this programmatic objective: (1) Integration and Oversight, (2) Crystal Accumulation Modeling (led by PNNL)/Higher Waste Loading Glasses (led by SRNL), (3) Melt Rate Evaluation and Modeling, and (4) Melter Scale Demonstrations. The details of these tasks can be found in the associated task plan WSRC-STI-2007-00483. The current study is focused on Task 2 (crystal accumulation modeling and higher waste loading glasses) and involves glass formulation and physical property testing by both PNNL and SRNL (as defined in the PNNL and SRNL test plans). The intent of this report is to document the chemical composition and Product Consistency Test (PCT) results and statistical analysis of PNNL's Test Matrix 1 glasses. Note that this document is only a compilation of the data collected by SRNL for PNNL's glasses in support of this task and no conclusions will be drawn.
Date: September 23, 2008
Creator: Raszewski, F; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

MATRIX 2 RESULTS OF THE FY07 ENHANCED DOE HIGH-LEVEL WASTE MELTER THROUGHPUT STUDIES AT SRNL

Description: High-level waste (HLW) throughput (i.e., the amount of waste processed per unit time) is a function of two critical parameters: waste loading (WL) and melt rate. For the Waste Treatment and Immobilization Plant (WTP) at the Hanford Site and the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS), increasing HLW throughput would significantly reduce the overall mission life cycle costs for the Department of Energy (DOE). The objective of this study was to generate supplemental validation data that could be used to determine the applicability of the current liquidus temperature (TL) model to expanded DWPF glass composition regions of interest based on higher WLs. Two specific flowsheets were used in this study to provide such insight: (1) Higher WL glasses (45 and 50%) based on future sludge batches that have (and have not) undergone the Al-dissolution process. (2) Coupled operations supported by the Salt Waste Processing Facility (SWPF), which increase the TiO{sub 2} concentration in glass to greater than 2 wt%. Glasses were also selected to address technical issues associated with Al{sub 2}O{sub 3} solubility, nepheline formation, and homogeneity issues for coupled operations. A test matrix of 28 glass compositions was developed to provide insight into these issues. The glasses were fabricated and characterized using chemical composition analysis, X-ray Diffraction (XRD), TL measurement and the Product Consistency Test (PCT). The results of this study are summarized below: (1) TiO{sub 2} concentrations up to {approx} 3.5 wt% were retained in DWPF type glasses, where retention is defined as the absence of crystalline TiO{sub 2} (i.e., unreacted or undissolved) in the as-fabricated glasses. Although this TiO{sub 2} content does not bound the projected SWPF high output flowsheet (up to 6 wt% TiO{sub 2} may be required in glass), these data demonstrate the potential for increasing the TiO{sub 2} limit ...
Date: October 23, 2008
Creator: Raszewski, F; Tommy Edwards, T & David Peeler, D
Partner: UNT Libraries Government Documents Department

PERMEABILITY OF SALTSTONE MEASUREMENT BY BEAM BENDING

Description: One of the goals of the Saltstone variability study is to identify (and, quantify the impact of) the operational and compositional variables that control or influence the important processing and performance properties of Saltstone mixes. A performance property for Saltstone mixes that is important but not routinely measured is the liquid permeability or saturated hydraulic conductivity of the cured Saltstone mix. The value for the saturated hydraulic conductivity is an input into the Performance Assessment for the SRS Z-Area vaults. Therefore, it is important to have a method available that allows for an accurate and reproducible measurement of permeability quickly and inexpensively. One such method that could potentially meet these requirements for the measurement of saturated hydraulic conductivity is the technique of beam bending, developed by Professor George Scherer at Princeton University. In order to determine the feasibility of this technique for Saltstone mixes, a summer student, David Feliciano, was hired to work at Princeton under the direction of George Scherer. This report details the results of this study which demonstrated the feasibility and applicability of the beam bending method to measurement of permeability of Saltstone samples. This research effort used samples made at Princeton from a Modular Caustic side solvent extraction Unit based simulant (MCU) and premix at a water to premix ratio of 0.60. The saturated hydraulic conductivities for these mixes were measured by the beam bending technique and the values determined were of the order of 1.4 to 3.4 x 10{sup -9} cm/sec. These values of hydraulic conductivity are consistent with independently measured values of this property on similar MCU based mixes by Dixon and Phifer. These values are also consistent with the hydraulic conductivity of a generic Saltstone mix measured by Langton in 1985. The high water to premix ratio used for Saltstone along with the ...
Date: January 30, 2008
Creator: Harbour, J; Tommy Edwards, T & Vickie Williams, V
Partner: UNT Libraries Government Documents Department