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At least 811 records · Page 45

Product Consistency Test Results for the High-Chromium Matrix Glasses

This report provides chemical analysis of a series of Product Consistency Test (PCT) leachates from simulated nuclear waste glasses. The resulting data will be used in the development of improved property/composition models. For some of the glass leachates, minor scatter among the triplicate values of some analytes was observed. For other leachates, there were more significant differences among the triplicate values. A review of the PCT data noted that there was little difference between the normalized values on the basis of targeted or measured glass composition. Several of the study glasses, both quenched and canister centerline cooled, have NC i values that are greater than the Hanford Tank Waste Treatment and Immobilization Plant immobilized low-activity waste constraint of 4 g/L for B, Na, and Si. For many of the study glasses, heat treatment had only a marginal impact on the NC i values. The samples of the Environmental Assessment (EA) reference glass included with each PCT set had inconsistent NC i values, although some degree of variation in NC i values for the EA glass is typical. The release rates for boron and sodium were highly correlated for the study glasses, while for the other analytes, less correlation was observed.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Composition Measurements of the LAW Phase 5 Glasses

This report provides the results from the chemical analyses of glass compositions for the Low-Activity Waste Phase 5 study glasses, a series of simulated nuclear waste glasses fabricated at Pacific Northwest National Laboratory. These data will be used in the development of enhanced property/composition models for waste glass vitrification at Hanford. Chemical analyses were performed on a representative sample of each of the quenched glasses to allow for comparisons with targeted compositions. The relative differences between the targeted and measured concentrations of CaO, Cl - , K 2 O, Li 2 O, and SO 3 for some of the glasses were greater than 10%. Several of these glass samples were rerun to verify original measurements; however, there were no significant changes in the measurements to indicate errors in preparation or analysis of the samples. These results can be used in further characterization of this series of glasses, including the normalization of Product Consistency Test results.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Product Consistency Test Results for the LAW Phase 5 Glasses

This report provides the results of the Vapor Hydration Test solutions and the Product Consistency Test leachates from the Low-Activity Waste Phase 5 glasses, a series of simulated nuclear waste glasses fabricated at the Pacific Northwest National Laboratory. The series included quenched and canister-centerline cooled versions of the glasses. These data will be used in the development of enhanced property/composition models for waste glass vitrification at Hanford. Several of the blanks had detectable amounts of sodium and/or silicon. The measured concentrations (mg/L) of boron, sodium, and silicon for the low-activity test reference material glass included with the Product Consistency Tests were much lower than the expected low-activity test reference material test results. A review of the Product Consistency Test data indicated that there was generally little difference between the normalized values based on targeted or measured glass composition. Heat treatment had various impacts on the normalized concentration values. Most of the glasses had NC B , NC Na , and NC Si values that were greater than the Hanford Tank Waste Treatment and Immobilization Plant low-activity waste constraint of 4 g/L. The release rates for boron, sodium, and silicon were highly correlated for the study glasses.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Composition Measurements of the Environmental Management Headquarters (EMHQ) Low-Activity Waste (LAW) Glasses

This report provides the results from the chemical analyses of glass compositions for the Environmental Management Headquarters Low-Activity Waste study glasses, a series of simulated nuclear waste glasses fabricated at Pacific Northwest National Laboratory. These data will be used in the development, validation, and implementation of enhanced property/composition models for waste glass vitrification at Hanford. Chemical analyses were performed on a representative sample of each of the quenched glasses to allow for comparisons with targeted compositions. The relative differences between the targeted and measured concentrations of Na 2 O, Li 2 O, and SO 3 for several of the glasses and B 2 O 3 in one of the glasses were greater than 10%. These results can be used in further characterization of this series of glasses, including the normalization of Product Consistency Test results.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Product Consistency Test Results for the Environmental Management Headquarters (EMHQ) Low-Activity Waste (LAW) Glasses

This report provides the results of the Product Consistency Test leachates from the Environmental Management Headquarters Low-Activity Waste glasses, a series of simulated nuclear waste glasses designed and fabricated at the Pacific Northwest National Laboratory. The series included quenched versions of the glasses. These data will be used in the development, validation, and implementation of enhanced property/composition models for waste glass vitrification at Hanford. The measured concentrations of the analytes in the test blank samples were below detection limits. The measured concentrations of B, Li, Na, and Si in the Approved Reference Material-1 samples included with the Product Consistency Tests fell within control chart values indicating proper test performance. The measured glass compositions for the study glasses were close to target values: therefore, little difference was seen when evaluating the normalized values using the targeted or measured glass compositions. The $NC_B$, $NC_{Na}$, and $NC_{Si}$ values were less than the Hanford Tank Waste Treatment and Immobilization Plant low-activity waste constraint of 4 g/L for all glasses.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Supply Chain Energy and Greenhouse Gas Analysis Using the Materials Flows through Industry (MFI) Tool: Examination of Decarbonization Technology Scenarios for the U.S. Glass Manufacturing Sector

Glass manufacturing is a major part of the U.S. economy, and glass products in multiple sectors - flat glass, container glass, and fiberglass - are a part of everyday life. Despite glass manufacturing's long history, there are still many opportunities for glass production to improve in terms of both in overall energy consumption and greenhouse gas (GHG) emission reduction. Scenarios for the flat, container, and fiberglass sectors show the effect that each improvement has on primary energy demand and GHG emissions, starting from an industry baseline that reflects current manufacturing practices. Using the National Renewable Energy Laboratory's Material Flows through Industry tool, multiple scenarios are examined for each glass sector by applying a combination of energy reduction, increased electrification, hydrogen cofiring, a more renewable electric grid, and increased use of cullet. Additional decarbonization options are possible for glass but are left for later analysis due to cost, feasibility, or data issues. Primary energy demand can be reduced by 75%-83% compared to baseline inputs, depending on the sector, and GHG emissions are reduced by 82%-86%. Applying the maximum level of improvements listed here has the potential to save over 300 million GJ and 25 million metric tons of GHGs by 2050.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Composition Measurements of the HLW APPS Glasses

This report provides the results from the chemical analyses of the glass compositions of the High Activity Waste Aspen Process Performance Simulation (HLW APPS) study glasses, a series of simulated nuclear waste glasses designed and fabricated at Pacific Northwest National Laboratory. These data will be used in the development, validation, and implementation of enhanced property/composition models for waste glass vitrification at Hanford. Chemical analyses were performed on a representative sample of each of the quenched glasses to allow for comparisons with targeted compositions. The relative differences between the targeted and measured concentrations of F- for three glasses and B 2 O 3 for five glasses were greater than 10%. These results can be used in further characterization of this series of glasses, including the normalization of Product Consistency Test results.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Impact Fracture and Fragmentation of Glass via the 3D Combined Finite-Discrete Element Method

A driving technical concern for the automobile industry is their assurance that developed windshield products meet Federal safety standards. Besides conducting innumerable glass breakage experiments, product developers also have the option of utilizing numerical approaches that can provide further insight into glass impact breakage, fracture, and fragmentation. The combined finite-discrete element method (FDEM) is one such tool and was used in this study to investigate 3D impact glass fracture processes. To enable this analysis, a generalized traction-separation model, which defines the constitutive relationship between the traction and separation in FDEM cohesive zone models, was introduced. The mechanical responses of a laminated glass and a glass plate under impact were then analyzed. For laminated glass, an impact fracture process was investigated and results were compared against corresponding experiments. Correspondingly, two glass plate impact fracture patterns, i.e., concentric fractures and radial fractures, were simulated. The results show that for both cases, FDEM simulated fracture processes and fracture patterns are in good agreement with the experimental observations. The work demonstrates that FDEM is an effective tool for modeling of fracture and fragmentation in glass.

42 ENGINEERING↗

Modeling and Characterization of Dynamic Failure of Glasses Under High Speed Impact

: In this chapter, the impact-induced dynamic failure of a glass block is studied using an integrated experimental/analytical approach. Both soda-lime and borosilicate glass materials are investigated. The Split Hopkinson Pressure Bar (SHPB) technique is used to conduct dynamic failure test of soda-lime glass first. The damage growth patterns and stress histories are reported for various glass specimen designs. Making use of a continuum damage mechanics (CDM)-based constitutive model, the initial failure and subsequent stiffness reduction of glass are simulated and investigated. Explicit finite element analyses are used to simulate the glass specimen impact event. A maximum shear stress-based damage evolution law is used in describing the glass damage process under combined compression/shear loading. The impact test results are used to quantify the critical shear stress for the soda-lime glass under examination.

continuum damage mechanics model↗

Investigation of ruthenium dioxide formation mechanisms in containment glass synthesized by liquid feed

The presenting paper focuses on the structural configuration of ruthenium in vitreous matrices with the objective of obtaining more insight into ruthenium incorporation and solubilization mechanisms in borosilicate glasses. To determine the structural effect of an increasing RuO{sub 2} in a borosilicate glass, a series of glass samples were selected from a benchmark composition. {sup 11}B NMR shows that the borate network is influenced by the presence of RuO{sub 2} in the glass: the addition of 2% RuO{sub 2} in a borosilicate glass led to a significant rise of BO{sub 4}. RuO{sub 2} precipitated in the glass does not seem to be the cause of this modification because when RuO{sub 2} increase there is no further change of BO{sub 4} fraction. This effect can be therefore attributed to RuO{sub 2} dissolved in the glass. RuO{sub 2} is known to have a very low solubility in borosilicate glasses (50 to 2000 ppm depending on the temperature, sodium concentration and conditions of synthesis). The link between the ruthenium and the borated network is not yet clearly identified, however, assumptions can be made such as the formation of Ru-O-B when a sufficient quantity of Ru is add (> 400 ppm). Ruthenium could play the role of silicon in increasing the possibility of bridging bond formation with boron coordination number IV.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Preparation and Characterization of Pu and Hf Bearing Lanthanide Borosilicate and Alumino-borosilicate Glasses - 15667

Eight borosilicate glasses with LaBS and ABS compositions containing plutonium and/or hafnium as a plutonium surrogate were prepared in Pt ampoules (Pu-bearing) and alumina or Pt crucibles (Hf-bearing) and characterized by X-ray diffraction, optical and scanning electron microscopy, infrared and Raman spectroscopy. Hf-bearing LaBS glasses were found to be amorphous whereas Pu-bearing glasses contained trace of plutonium dioxide and britholite. Hf and Fe bearing ABS glasses contained minor spinel structure phase. As followed from optical and SEM studies Hf-bearing LaBS glasses were more homogeneous than Pu-bearing and ABS glasses. The structure of the anionic motif of the glasses investigated by IR and Raman spectroscopy is typical of the glasses with relatively low silica content. (authors)

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Robust and High-Waste Loaded Glass Formulations for Hanford Low-Activity Waste - 19050

The Hanford Low-Activity Waste (LAW) vitrification facility will receive LAW batches with abruptly changing compositions that span relatively broad ranges. In particular, the concentration ratios of sodium-to-sulfate, -chloride, -chromate, -phosphate, -potassium, and -aluminate create challenges in glass formulation. Glass compositions that simultaneously satisfy several processability, product quality, and composition constraints with sufficient confidence must be formulated for each LAW batch in near-realtime to enable desired throughput. A method for developing glass compositions while maximizing the waste loading and the process robustness was developed. This method compiled the glass composition-property data collected over nearly two decades, primarily by Pacific Northwest National Laboratory, The Catholic University of America, and Savannah River National Laboratory, in support of both the Hanford Tank Waste Treatment and Immobilization Plant project and the U.S. Department of Energy Office of River Protection Enhanced Waste Glass project. These data were used to develop models that link the melter feed composition to the resulting glass properties. Mathematical constructs were developed to optimize glass compositions for each waste batch in real-time that will simultaneously satisfy processability, product quality, and composition constraints with sufficient statistical confidence. Property prediction and various process uncertainties were reflected in the formulation. The formulation approach directly lends itself to adjustment of glass formulation to achieve program goals. This presentation will summarize the formulation approach and supporting data. (authors)

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Vibrational dynamics in the undercooled liquid of ultra-fragile metallic glasses

Here, the lattice vibrational dynamics in ultra-fragile Pt 57 Cu 23 P 20 and Pt 60 Cu 20 P 20 glasses were investigated using in situ inelastic neutron scattering to measure the evolution of the phonon density of states (DOS) through the glass transition, into the undercooled liquid phase, and through crystallization. The phonon DOS curves are remarkably similar for the undercooled liquids and the amorphous solids. The vibrational entropy was obtained with these phonon DOS curves, and changes in vibrational entropy caused by the glass transition are less than 0.05 k B /atom. For these highly fragile metal/metalloid glasses, the excess vibrational entropy of the undercooled liquid is about 0.5–1.5 Jmol -1 K -1 , compared to 0.1 Jmol -1 K -1 reported earlier for stronger Cu–Zr glasses. Our work suggests that, consistent with our previous report for less fragile metallic glasses, the fraction of the total excess entropy that is vibrational is small, and the discontinuity in excess entropy at the glass transition is mainly due to configurational entropy.

36 MATERIALS SCIENCE↗

Deep glassy state dynamic data challenge glass models: Elastic models

The idea of an “ideal” glass transition temperature has persisted at least since the work from Kauzmann when it was observed that the entropy of glass-forming liquids extrapolated to below that of the crystal, thus suggesting the need for a phase transition at a finite or non-zero absolute temperature. This thermodynamic paradox was also found to be related to the observations of a diverging of the extrapolated viscosity or relaxation times at a temperature near to this ideal glass transition. Recently, however, we have carried out experiments using both an ancient amber material and an ultra-stable amorphous fluoropolymer that challenge the ideas of the divergence of the viscosity or relaxation times at this ideal glass transition. In the present manuscript we have evaluated two theories of the glass transition that are based on ideas related to elasticity of the amorphous glass-forming material. We find that the models from both J. Dyre and his group and of K.S. Schweizer and his group not only show non-diverging behavior but are also in some agreement with the new data, though still showing somewhat slower dynamics than those observed in the experiments. The work shows that the data are good enough to distinguish between theories and it is suggested that other mechanisms may be needed to fully describe the non-diverging responses of the ultra-stable glasses.

36 MATERIALS SCIENCE↗

LionGlass™: A low‐melting, carbonate‐free alternative to soda lime silicate glass

LionGlass™ is Penn State University's patent-pending alumino-silicophosphate glass compositional family that offers, for the first time, a viable low-melting, carbonate-free alternative to soda lime silicate glass by (a) lowering the melting temperature by up to 400°C compared to soda lime silicate glass and (b) eliminating the use of carbonate batch materials. The viscosity curve of LionGlass is shifted downward in temperature compared to soda lime silicate glass, enabling melting at much lower temperatures. LionGlass also has significantly improved resistance to crack initiation compared to soda lime silicate glass. Other properties, such as thermal expansion coefficient and optical dispersion curve, are comparable to those of traditional soda lime silicate glass.

Lion-Glass↗

SCOPING MELTING STUDIES OF HIGH ALUMINA WASTE GLASS COMPOSITIONS

Glass property models will be used at the Hanford Tank Waste Treatment and Immobilization Plant to formulate durable high-level waste glasses for disposal. A major effort is focused on expanding glass property models to cover a broader range of wastes and higher waste-loaded glasses. As a part of this effort, a statistically designed matrix of high-alumina glass compositions was developed. Forty five compositions were selected from the matrix to evaluate glass properties. Of these compositions, thirty three produced homogeneous glasses. The other twelve compositions contained segregated phases and high crystallinity; these were iteratively modified in an attempt to produce homogeneous glass samples while altering the original composition as little as possible. This paper focuses on the characterization of the twelve inhomogeneous compositions and their modifications using X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy.

Kroll, Jared O.↗

Pressure‐induced polyamorphism in lanthanide‐solute metallic glasses

The electronic structure inheritance of lanthanide‐solvent atoms in lanthanide‐based metallic glasses has been proposed. Is a polyamorphism possible in lanthanide‐solute metallic glasses? So far, polyamorphic phase transitions in metallic glass containing lanthanide have been observed only in lanthanide‐solvent metallic glasses. Here, a pressure‐induced transition between two distinct amorphous states, accompanied by a 7% volume collapse at ambient pressure, was observed in La 43.4 Pr 18.6 Al 14 Cu 24 metallic glass, with low lanthanide content, by using in situ X‐ray total scattering method. The transformation also indicated by changes in short range and medium range order. Thus, it is proposed that the lanthanide‐solute metallic glasses also inherit 4 f electronic transition from pure lanthanide element in polyamorphic transition. This discovery offers a supplement to research on lanthanide‐based metallic glasses, which further provides a new perspective of the polyamorphic transformation in metallic glasses containing lanthanide element.

Li, Liangliang↗

NanoSIMS Imaging Alternation Layers of a Leached SON68 Glass Via A FIB-made Wedged Crater

Currently, nuclear wastes are commonly immobilized into glasses because of their long-term durability. Exposure to water for long periods of time, however, will eventually corrode the waste form and is the leading potential avenue for radionuclide release into the environment. Because such slow processes cannot be experimentally tested, the prediction of release requires a thorough understanding the mechanisms governing glass corrosion. In addition, due to the exceptional durability of glass, much of the testing must be performed on high-surface-area powders. A technique that can provide accurate compositional profiles with very precise depth resolution for non-flat samples would be a major benefit to the field. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) depth profiling is an excellent tool that has long been used to examine corrosion layers of glass. The roughness of the buried corrosion layers, however, causes the corresponding SIMS depth profiles to exhibit erroneously wide interfaces. In this study, NanoSIMS was used to image the cross-section of the corrosion layers of a leached SON68 glass sample. A wedged crater was prepared by a focused ion beam (FIB) instrument to obtain a 5× improvement in depth resolution for NanoSIMS measurements. This increase in resolution allowed us to confirm that the breakdown of the silica glass network is further from the pristine glass than a second dissolution front for boron, another glass former. The existence of these two distinct interfaces, separated by only ~20 nm distance in depth, was not apparent by traditional ToF-SIMS depth profiling but has been confirmed also by atom probe tomography. This novel sample geometry will be a major benefit to efficient NanoSIMS sampling of irregular interfaces at the nanometer scale that would otherwise be obscured within ToF-SIMS depth profiles.

Environmental Molecular Sciences Laboratory↗