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At least 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

On the induction of homogeneous bulk crystallization in Eu-doped calcium aluminosilicate glass by applying simultaneous high pressure and temperature

From initial calcium aluminosilicate glass, transparent glass-ceramics have been successfully synthesized under simultaneous high pressure and temperature (SHPT). Possible homogeneous volumetric crystallization of this glassy system, which was not achieved previously by means of conventional heat treatment, has been put in evidence with a SHPT procedure. Structural, mechanical, and optical properties of glass and glass-ceramic obtained were investigated. Raman spectroscopy and X-ray diffraction allowed to identify two main crystalline phases: merwinite [Ca{sub 3}Mg(SiO{sub 4}){sub 2}] and diopside [CaMgSi{sub 2}O{sub 6}]. A Raman scanning profile showed that the formation of merwinite is quite homogeneous over the bulk sample. However, the sample surface also contains significant diopside crystals. Instrumented Berkovich nanoindentation was applied to determine the effect of SHPT on hardness from glass to glass-ceramic. For Eu-doped samples, the broadband emission due to 4f{sup 6}5d{sup 1} → 4f{sup 7} transition of Eu{sup 2+} was studied in both host systems. Additionally, the {sup 5}D{sub 0} → {sup 7}F{sub J} transition of Eu{sup 3+} was used as an environment probe in the pristine glass and the glass-ceramic.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Effect of chlorine and chromium on sulfur solubility in low-activity waste glass

According to an empirical sulfur solubility model developed from over 200 simulated low-activity waste (LAW) glasses, chlorine and chromium show strong effects on lowering sulfur solubility in glass. This work was aimed at understanding the mechanism behind the negative effect of chlorine and chromium on sulfur solubility. A simplified LAW glass was prepared and saturated by sodium sulfate, sodium chloride, and sodium chromate salts as single components and as mixtures with different ratios at 25 mol%, 50 mol%, and 75 mol% of sulfate mixed with chloride or chromate. A crucible-scale salt-saturation was performed by mixing the crushed glass powder with an excess amount of salts, melting at 1150 °C for one hour, and quenching. Three mixing-melting-quenching cycles were applied to determine saturation concentrations of sulfur, chromium, and chlorine incorporated into the simplified LAW glass. The glass compositions were analyzed by inductively coupled plasma–atomic emission spectroscopy, ion chromatography, and X-ray emission spectroscopy. It is proposed that the negative effect of chlorine and chromium on sulfur solubility can be explained based on the simple hypothesis that sulfur, chlorine, and chromium are present in the glass as anions competing for the voids or interstitial sites of the glass matrix, and that their solubility strongly depends on the effective size of corresponding anions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Simulations of the surfaces of soda lime aluminoborosilicate glasses exposed to water

Molecular dynamics simulations of 7 compositionally different sodium calcium alumino–borosilicate glasses showed formation of 4 B and 5 Al more consistent with experimental data without compromising the other structural features that match experimental results observed in recent simulations of these glasses. Analysis of the dry surfaces of these glasses show a lack of 4 B in the top 5–6 Å of the surface in comparison to the bulk concentration for all glasses and no 5 Al. Upon exposure to water, the simulations show that the 3 B in the top 5–6 Å of the glasses are preferentially attacked, decreasing the number of B bonds to O originally from the glass, indicating a change in the glass network. Inclusion of all B–O bonds in the top 5–6 Å (i.e., including O from water) shows a decrease in 3 B but an increase in 4 B that is consistent with NEXAFS analysis, which the simulations show are hydroxylated. Furthermore, there is an increase in the concentration of 3 Al in the dry surface in comparison to the bulk, but exposure to water converts almost all of these 3 Al to 4 Al. Hydroxyl concentrations vary from 2.6/nm 2 to 4.1/nm 2 , with SiOH and BOH dominating these surface hydroxyls. Upon exposure to water, network linkages to B are preferentially ruptured. This, and the preferential loss of the nonbridging oxygen sites attached to Na, provide atomistic evidence of the initial stages of removal of B and Na from glass surfaces exposed to water.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Applicability of iron phosphate glass medium for loading NaCl originated from seawater used for cooling the stricken power reactors

As the part of investigation for immobilization of the sludge as one of the radioactive wastes arising from the treatment of contaminated water at Fukushima Dai-ichi nuclear power plant, applicability of vitrification method has been evaluated as a candidate technique. The aim of this study is to evaluate the influence of NaCl as one of the main constituents of sludge, on glass formation and glass properties. Two kinds of iron phosphate glass (IPG) media in the xFe{sub 2}O{sub 3}-(100-x)P{sub 2}O{sub 5}, with x=30 and 35 (mol%) were chosen and the glass formation, structure and properties including density, coefficient of thermal expansion, glass transition temperature, onset crystallization temperature and chemical durability of NaCl-loaded IPG were studied. The results are summarized as follows. Sodium chloride, NaCl could be loaded into IPG medium as Na{sub 2}O and Cl contents and their loading ratio could be up to 19 and 15 mol%, respectively. Majority of Cl content of raw material NaCl was thought to be volatilized during glass melting. Loading NaCl into IPG induces to de-polymerize glass network of phosphate chains, leads to decrease both glass transition and onset crystallization temperatures, and to increase coefficient of thermal expansion. NaCl-loaded IPG indicated good chemical durability in case of using 35Fe{sub 2}O{sub 3}- 65P{sub 2}O{sub 5} medium. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2011

SUMMARY OF 2010 DOE EM INTERNATIONAL PROGRAM STUDIES OF WASTE GLASS MELT RATE ENHANCEMENT

A collaborative study has been established under the U.S. Department of Energy (DOE) Office of Environmental Management International Program between the Savannah River National Laboratory (SRNL) and the V. G. Khlopin Radium Institute (KRI) in St. Petersburg, Russia, to investigate potential improvements in melt rate via chemical additions to the glass frit. Researchers at KRI suggested a methodology for selecting frit additives based on empirical coefficients for optimization of glass melting available in the Russian literature. Using these coefficients, KRI identified B{sub 2}O{sub 3}, CuO, and MnO as frit additives that were likely to improve melt rate without having adverse effects on crystallization of the glass or its chemical durability. The results of the melt rate testing in the SMK melter showed that the slurry feed rate (used as a gauge of melt rate) could be significantly increased when MnO or CuO were added to Frit 550 with the SMR-2 sludge. The feed rates increased by about 27% when MnO was added to the frit and by about 26% when CuO was added to the frit, as compared to earlier results for Frit 550 alone. The impact of adding additional B{sub 2}O{sub 3} to the frit was minor when added with CuO. The additional B{sub 2}O{sub 3} showed a more significant, 39% improvement in melt rate when added with MnO. The additional B{sub 2}O{sub 3} also reduced the viscosity of the glasses during pouring. Samples of the glasses from the melt rate testing characterized at SRNL showed that there were no significant impacts on crystallization of the glasses. All of the glasses had very good chemical durability. Chemical composition measurements showed that the frit additives were present in concentrations below the targeted values in some of the glasses. Therefore, it is possible that higher concentrations of these additives may further improve melt rate, although the impacts of higher concentrations of these components on crystallization and durability would need to be determined. Overall, the results show an excellent potential for these additives to significantly improve waste throughput for DOE vitrification facilities. A complete report from KRI is included as an appendix to this document.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2011

FINAL REPORT TESTING OF IRON PHOSPHATE LAW GLASS (VSL-11R2340-1) 04/25/2011 REV 0 06/10/2011

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 will likely be directed to a national deep geological disposal facility for high-level nuclear waste. The ILA W and IHLW products must meet a variety of requirements with respect to protection of the environment before they can be accepted for disposal. The objectives of the work reported herein were to assess the corrosion of Inconel 690 and 693 in the FeP glass developed by MS&T and to measure key high temperature properties of the LAW iron phosphate glass. Specific objectives of these tests were the following: (1) Determination of the extent of corrosion of Inconel 690 and 693 in LAW FeP glass at 1050, 1l00, and 1150 C; (2) Determination of the extent of corrosion of Inconel 690 and 693 in LAW FeP glass in the presence of an electric field; (3) Measurement of the high temperature specific heat of the LAW FeP glass; (4) Measurement of the high temperature density of the LAW FeP glass; (5) Measurement of the high temperature thermal diffusivity of the LAW FeP glass; and (6) Calculation of the high temperature thermal conductivity of the LAW FeP glass from the above three measured properties.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2011

Refractory Glass Seals for SOFC

One of the critical challenges facing planar solid oxide fuel cell (SOFC) technology is the need for reliable sealing technology. Seals must exhibit long-term stability and mechanical integrity in the high temperature SOFC environment during normal and transient operation. Several different approaches for sealing SOFC stacks are under development, including glass or glass-ceramic seals, metallic brazes, and compressive seals. Among glass seals, rigid glass-ceramics, self-healing glass, and composite glass approaches have been investigated under the SECA Core Technology Program. The U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL) has developed the refractory glass approach in light of the fact that higher sealing temperatures (e.g., 930-1000 degrees C) may enhance the ultimate in-service bulk strength and electrical conductivity of contact materials, as well as the bonding strength between contact materials and adjacent SOFC components, such as interconnect coatings and electrodes. This report summarizes the thermal, chemical, mechanical, and electrical properties of the refractory sealing glass.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2011

Comparison of glass surfaces as a countertop material to existing surfaces

Gleen Glass, a small production glass company that creates countertops, was selected for the Technology Assistance Program through Pacific Northwest National Laboratory. Gleen Glass was seeking material property analysis comparing glass as a countertop material to current surfaces (i.e. marble, granite and engineered stone). With samples provided from Gleen Glass, testing was done on granite, marble, and 3 different glass surfaces ('Journey,' 'Pebble,' and 'Gleen'). Results showed the glass surfaces have a lower density, lower water absorption, and are stronger in compressive and flexural tests as compared to granite and marble. Thermal shock tests showed the glass failed when objects with a high thermal mass are placed directly on them, whereas marble and granite did not fracture under these conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Analysis of DWPF Sludge Batch 6 (Macrobatch 7): Pour Stream Glass Samples

The Defense Waste Processing Facility (DWPF) began processing Sludge Batch 6 (SB6), also referred to as Macrobatch 7 (MB7), in June 2010. SB6 is a blend of the heel of Tank 40 from Sludge Batch 5 (SB5), H-Canyon Np transfers and SB6 that was transferred to Tank 40 from Tank 51.1 SB6 was processed using Frit 418. Sludge is received into the DWPF Chemical Processing Cell (CPC) and is processed through the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator Tank (SME). The treated sludge slurry is then transferred to the Melter Feed Tank (MFT) and fed to the melter. During processing of each sludge batch, the DWPF is required to take at least one glass sample to meet the objectives of the Glass Product Control Program (GPCP) and to complete the necessary Production Records so that the final glass product may be disposed of at a Federal Repository. The DWPF requested various analyses of radioactive glass samples obtained from the melter pour stream during processing of SB6 as well as reduction/oxidation (REDOX) analysis of MFT samples to determine the impact of Argon bubbling. Sample analysis followed the Task Technical and Quality Assurance Plan (TTQAP) and an Analytical Study Plan (ASP). Four Pour Stream (PS) glass samples and two MFT slurry samples were delivered to the Savannah River National Laboratory (SRNL) from the DWPF. Table 1-1 lists the sample information for each pour stream glass sample. SB6 PS3 (S03472) was selected as the official pour stream sample for SB6 and full analysis was requested. This report details the visual observations of the as-received SB6 PS No.3 glass sample as well as results for the chemical composition, Product Consistency Test (PCT), radionuclide content, noble metals, and glass density. REDOX results will be provided for all four pour stream samples and vitrified samples of MFT-558 and MFT-568A. Where appropriate, data from other pour stream samples will be provided.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Hydrothermal Alteration of Glass from Underground Nuclear Tests: Formation and Transport of Pu-clay Colloids at the Nevada National Security Site

The testing of nuclear weapons at the Nevada National Security Site (NNSS), formerly the Nevada Test Site (NTS), has led to the deposition of substantial quantities of plutonium into the environment. Approximately 2.8 metric tons (3.1×10 4 TBq) of Pu were deposited in the NNSS subsurface as a result of underground nuclear testing. While 3 H is the most abundant anthropogenic radionuclide deposited in the NNSS subsurface (4.7×10 6 TBq), plutonium is the most abundant from a molar standpoint. The only radioactive elements in greater molar abundance are the naturally occurring K, Th, and U isotopes. 239 Pu and 240 Pu represent the majority of alpha-emitting Pu isotopes. The extreme temperatures associated with underground nuclear tests and the refractory nature of Pu results in most of the Pu (98%) being sequestered in melted rock, referred to as nuclear melt glass (Iaea, 1998). As a result, Pu release to groundwater is controlled, in large part, by the leaching (or dissolution) of nuclear melt glass over time. The factors affecting glass dissolution rates have been studied extensively. The dissolution of Pu-containing borosilicate nuclear waste glasses at 90ºC has been shown to lead to the formation of dioctahedral smectite colloids. Colloid-facilitated transport of Pu at the NNSS has been observed. Recent groundwater samples collected from a number of contaminated wells have yielded a wide range of Pu concentrations from 0.00022 to 2.0 Bq/L. While Pu concentrations tend to fall below the Maximum Contaminant Level (MCL) established by the Environmental Protection Agency (EPA) for drinking water (0.56 Bq/L), we do not yet understand what factors limit the Pu concentration or its transport behavior. To quantify the upper limit of Pu concentrations produced as a result of melt glass dissolution and determine the nature of colloids and Pu associations, we performed a 3 year nuclear melt glass dissolution experiment across a range of temperatures (25-200 °C) that represent hydrothermal conditions representative of the underground nuclear test cavities (when groundwater has re-saturated the nuclear melt glass and glass dissolution occurs). Colloid loads and Pu concentrations were monitored along with the mineralogy of both the colloids and the secondary mineral phases. The intent was to establish an upper limit for Pu concentrations at the NNSS, provide context regarding the Pu concentrations observed at the NNSS to date and the Pu concentrations that may be observed in the future. The results provide a conceptual model for the risks posed by Pu migration at the NNSS.

36 MATERIALS SCIENCE↗
DOE OSTI2020

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↗
DOE OSTI2021

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↗
DOE OSTI2021

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↗
DOE OSTI2022

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↗
DOE OSTI2022

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↗
DOE OSTI2023

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↗
DOE OSTI2023

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↗
DOE OSTI2021

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↗