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Sample records for r7t7-type nuclear glass

  1. Simulated alteration tests on non-radioactive SON 68 nuclear glass in the presence of corrosion products and environmental materials

    NASA Astrophysics Data System (ADS)

    Jollivet, Patrick; Minet, Yves; Nicolas, Michèle; Vernaz, Étienne

    2000-10-01

    Alteration tests with non-radioactive French SON 68 (R7T7-type) nuclear glass in the presence of simulated metal canister corrosion products (CP) or environmental materials (EM) were simulated using the LIXIVER2 computer code. The code incorporates hypotheses concerning glass alteration in aqueous media based on the first-order kinetic law for total silicon with variable silicon retention in the gel and silicon diffusion in the gel interstitial water, coupled with silicon adsorption and diffusion in the materials in contact with the glass. The canister CP are considered as a localized medium with a mass adsorption capacity Rad, while the EM are considered as a porous medium with a diffusion coefficient Dp and a distribution coefficient Kd. L IXIVER2 simulates these media in one-dimensional Cartesian geometry. The Kd values determined by simulating alteration tests logically increase with the aggressiveness of the materials with respect to the glass.

  2. Turning nuclear waste into glass

    SciTech Connect

    Pegg, Ian L.

    2015-02-15

    Vitrification has emerged as the treatment option of choice for the most dangerous radioactive waste. But dealing with the nuclear waste legacy of the Cold War will require state-of-the-art facilities and advanced glass formulations.

  3. Natural analogues of nuclear waste glass corrosion.

    SciTech Connect

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-06

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses.

  4. Crystallization during processing of nuclear waste glass

    SciTech Connect

    Hrma, Pavel R.

    2010-12-01

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glassmaking are reviewed.

  5. Systems approach to nuclear waste glass development

    SciTech Connect

    Jantzen, C M

    1986-01-01

    Development of a host solid for the immobilization of nuclear waste has focused on various vitreous wasteforms. The systems approach requires that parameters affecting product performance and processing be considered simultaneously. Application of the systems approach indicates that borosilicate glasses are, overall, the most suitable glasses for the immobilization of nuclear waste. Phosphate glasses are highly durable; but the glass melts are highly corrosive and the glasses have poor thermal stability and low solubility for many waste components. High-silica glasses have good chemical durability, thermal stability, and mechanical stability, but the associated high melting temperatures increase volatilization of hazardous species in the waste. Borosilicate glasses are chemically durable and are stable both thermally and mechanically. The borosilicate melts are generally less corrosive than commercial glasses, and the melt temperature miimizes excessive volatility of hazardous species. Optimization of borosilicate waste glass formulations has led to their acceptance as the reference nuclear wasteform in the United States, United Kingdom, Belgium, Germany, France, Sweden, Switzerland, and Japan.

  6. Mechanical properties of nuclear waste glasses

    NASA Astrophysics Data System (ADS)

    Connelly, A. J.; Hand, R. J.; Bingham, P. A.; Hyatt, N. C.

    2011-01-01

    The mechanical properties of nuclear waste glasses are important as they will determine the degree of cracking that may occur either on cooling or following a handling accident. Recent interest in the vitrification of intermediate level radioactive waste (ILW) as well as high level radioactive waste (HLW) has led to the development of new waste glass compositions that have not previously been characterised. Therefore the mechanical properties, including Young's modulus, Poisson's ratio, hardness, indentation fracture toughness and brittleness of a series of glasses designed to safely incorporate wet ILW have been investigated. The results are presented and compared with the equivalent properties of an inactive simulant of the current UK HLW glass and other nuclear waste glasses from the literature. The higher density glasses tend to have slightly lower hardness and indentation fracture toughness values and slightly higher brittleness values, however, it is shown that the variations in mechanical properties between these different glasses are limited, are well within the range of published values for nuclear waste glasses, and that the surveyed data for all radioactive waste glasses fall within relatively narrow range.

  7. Extrapolation of nuclear waste glass aging

    SciTech Connect

    Byers, C.D.; Ewing, R.C.; Jercinovic, M.J.; Keil, K.

    1984-01-01

    Increased confidence is provided to the extrapolation of long-term waste form behavior by comparing the alteration of experimentally aged natural basaltic glass to the condition of the same glass as it has been geologically aged. The similarity between the laboratory and geologic alterations indicates that important aging variables have been identified and incorporated into the laboratory experiments. This provides credibility to the long-term predictions made for waste form borosilicate glasses using similar experimental procedures. In addition, these experiments have demonstrated that the aging processes for natural basaltic glass are relevant to the alteration of nuclear waste glasses, as both appear to react via similar processes. The alteration of a synthetic basaltic glass was measured in MCC-1 tests done at 90/sup 0/C, a SA/V of 0.1 cm/sup -1/ and time periods up to 182 days. Tests were also done using (1) MCC-2 procedures at 190/sup 0/C, a SA/V of 0.1 cm/sup -1/ and time periods up to 91 days and (2) hydration tests in saturated water vapor at 240/sup 0/C, a SA/V of approx. 10/sup 6/ cm/sup -1/, and time periods up to 63 days. These results are compared to alteration observed in natural basaltic glasses of great age. 6 references, 6 figures, 1 table.

  8. THERMOCHEMICAL MODELING OF NUCLEAR WASTE GLASS

    EPA Science Inventory

    The development of assessed and consistent phase equilibria and thermodynamic data for major glass constituents used to incorporate high-level nuclear waste is discussed in this paper. The initial research has included the binary Na{sub 2}O-SiO{sub 2}, Na{sub 2}O-Al{sub 2}O{sub ...

  9. Glass produced by underground nuclear explosions. [Rainier

    SciTech Connect

    Schwartz, L.; Piwinskii, A.; Ryerson, F.; Tewes, H.; Beiriger, W.

    1983-01-01

    Detonation of an underground nuclear explosive produces a strong shock wave which propagates spherically outward, vaporizing the explosive and nearby rock and melting, the surrounding rock. The vaporized material expands adiabatically, forming a cavity. As the energy is dissipated during the cavity formation process, the explosive and rock debris condense and mix with the melted rock. The melt flows to the bottom of the cavity where it is quenched by fractured rock fragments falling from above as the cavity collapses. Measurements indicate that about 740 tonnes of rock and/or soil are melted for every kiloton (10/sup 12/ calories) of explosive energy, or about 25% of the explosive energy goes to melting rock. The resulting glass composition reflects the composition of the unaltered rock with explosive debris. The appearance ranges from white pumice to dense, dark lava. The bulk composition and color vary with the amount of explosive iron incorporated into the glass. The refractory explosion products are mixed with the solidified melt, although the degree of mixing is variable. Electron microprobe studies of glasses produced by Rainier in welded tuff have produced the following results: glasses are dehydrated relative to the host media, glasses are extremely heterogeneous on a 20 ..mu..m scale, a ubiquitous feature is the presence of dark marble-cake regions in the glass, which were locally enriched in iron and may be related to the debris, optically amorphous regions provide evidence of shock melting, only limited major element redistribution and homogenization occur within the cavity.

  10. Thermodynamic model of natural, medieval and nuclear waste glass durability

    SciTech Connect

    Jantzen, C.M.; Plodinec, M.J.

    1983-01-01

    A thermodynamic model of glass durability based on hydration of structural units has been applied to natural glass, medieval window glasses, and glasses containing nuclear waste. The relative durability predicted from the calculated thermodynamics correlates directly with the experimentally observed release of structural silicon in the leaching solution in short-term laboratory tests. By choosing natural glasses and ancient glasses whose long-term performance is known, and which bracket the durability of waste glasses, the long-term stability of nuclear waste glasses can be interpolated among these materials. The current Savannah River defense waste glass formulation is as durable as natural basalt from the Hanford Reservation (10/sup 6/ years old). The thermodynamic hydration energy is shown to be related to the bond energetics of the glass. 69 references, 2 figures, 1 table.

  11. Compositional threshold for Nuclear Waste Glass Durability

    SciTech Connect

    Kruger, Albert A.; Farooqi, Rahmatullah; Hrma, Pavel R.

    2013-04-24

    Within the composition space of glasses, a distinct threshold appears to exist that separates "good" glasses, i.e., those which are sufficiently durable, from "bad" glasses of a low durability. The objective of our research is to clarify the origin of this threshold by exploring the relationship between glass composition, glass structure and chemical durability around the threshold region.

  12. Spectroscopic investigation of U, Np and Th in nuclear glasses

    NASA Astrophysics Data System (ADS)

    Calas, G.; Galoisy, L. V.; Petit-Maire, D.

    2011-12-01

    Vitrification of high-level radioactive waste in borosilicate glasses is currently used on an industrial scale in several countries. The fundamental properties of the waste forms are their chemical and mechanical durability against the forcing conditions represented by chemical alteration or internal/external irradiation. The waste immobilized in glass is composed of over 30 different nuclear fission and activation products, as well as minor actinides. The oxidation state and local atomic coordination of long-lived radionuclides are important parameters to understand the long-term evolution of the glass. We present an overview of the local structure around actinides in glasses similar to the French nuclear glass. X-Ray absorption spectroscopy has been used to probe the local environment around uranium, neptunium and thorium in these glasses. It is combined with with UV-visible spectroscopy, used to get selective information on the surrounding of U(IV), U(V) and U(VI) in glasses. Our spectroscopic data show that U, Np and Th occur in nuclear glasses in a peculiar surrounding showing significant differences with the crystal chemistry of these elements in crystalline compounds. Element speciation may be used as a pertinent parameter to follow the long-term stability of nuclear glasses, either under irradiation or during the alteration of the glass.

  13. Gamma radiation induced changes in nuclear waste glass containing Eu

    NASA Astrophysics Data System (ADS)

    Mohapatra, M.; Kadam, R. M.; Mishra, R. K.; Kaushik, C. P.; Tomar, B. S.; Godbole, S. V.

    2011-10-01

    Gamma radiation induced changes were investigated in sodium-barium borosilicate glasses containing Eu. The glass composition was similar to that of nuclear waste glasses used for vitrifying Trombay research reactor nuclear waste at Bhabha Atomic Research Centre, India. Photoluminescence (PL) and electron paramagnetic resonance (EPR) techniques were used to study the speciation of the rare earth (RE) ion in the matrix before and after gamma irradiation. Judd-Ofelt ( J- O) analyses of the emission spectra were done before and after irradiation. The spin counting technique was employed to quantify the number of defect centres formed in the glass at the highest gamma dose studied. PL data suggested the stabilisation of the trivalent RE ion in the borosilicate glass matrix both before and after irradiation. It was also observed that, the RE ion distributes itself in two different environments in the irradiated glass. From the EPR data it was observed that, boron oxygen hole centre based radicals are the predominant defect centres produced in the glass after irradiation along with small amount of E’ centres. From the spin counting studies the concentration of defect centres in the glass was calculated to be 350 ppm at 900 kGy. This indicated the fact that bulk of the glass remained unaffected after gamma irradiation up to 900 kGy.

  14. Melting of foaming batches: Nuclear waste glass

    SciTech Connect

    Hrma, P.

    1990-10-01

    A simple model is presented for the rate of melting of a batch blanket in an electric glassmelting furnace. The melting process is assumed to be jointly controlled by the heat transfer from the pool of molten glass and the batch-to-glass conversion kinetics. Factors affecting the melting rate in the conversion-controlled regime are discussed. Attention is paid to gas evolution from redox reactions in waste glass batches and component accumulation within the blanket. It is suggested that the high rate of the blanket-free melting in a mechanically agitated furnace is made possible by increasing the rate of melt surface renewal. 27 refs.

  15. Electron beam irradiation effects in Trombay nuclear waste glass

    NASA Astrophysics Data System (ADS)

    Mohapatra, M.; Kadam, R. M.; Mishra, R. K.; Dutta, D.; Pujari, P. K.; Kaushik, C. P.; Kshirsagar, R. J.; Tomar, B. S.; Godbole, S. V.

    2011-10-01

    Spectroscopic investigations were carried out on electron beam irradiated sodium barium borosilicate glasses, which is the base glass for immobilization of nuclear high level radioactive waste, generated from the research reactors at Bhabha Atomic Research Centre, Trombay. This was done in order to access the defects generated in it under long term irradiation. Electron paramagnetic resonance was used to identify the defect centers generated in the borosilicate glass after irradiation. In addition, positron annihilation spectroscopy and infrared investigations were done on the samples to evaluate the radiation induced changes in the glass. It was found that, boron-oxygen and silicon based hole centers along with E' centers are getting formed in the glass after irradiation due to the breaking of the Si sbnd O bonds at regular tetrahedron sites of Si sbnd O sbnd Si. The positron annihilation spectroscopy data gave an idea regarding the free volume size and fraction of the glasses before and after irradiation. It was seen that, after irradiation the free volume size in the glass increased with creation of additional sites. Microwave power variation and temperature variation studies suggested the formation of at least five different radicals in the irradiated glasses. The spin Hamiltonian parameter of all the radical species were determined by computer simulation. An electron paramagnetic resonance spin counting technique was employed to evaluate the defect concentration in the glasses after irradiation.

  16. NUCLEAR WASTE GLASSES CONTINUOUS MELTING AND BULK VITRIFICAITON

    SciTech Connect

    KRUGER AA; HRMA PR

    2008-03-24

    This contribution addresses various aspects of nuclear waste vitrification. Nuclear wastes have a variety of components and composition ranges. For each waste composition, the glass must be formulated to possess acceptable processing and product behavior defined in terms of physical and chemical properties that guarantee the glass can be easily made and resist environmental degradation. Glass formulation is facilitated by developing property-composition models, and the strategy of model development and application is reviewed. However, the large variability of waste compositions presents numerous additional challenges: insoluble solids and molten salts may segregate; foam may hinder heat transfer and slow down the process; molten salts may accumulate in container refractory walls; the glass on cooling may precipitate crystalline phases. These problems need targeted exploratory research. Examples of specific problems and their possible solutions are discussed.

  17. Nuclear waste glass product consistency test (PCT), Version 5. 0

    SciTech Connect

    Jantzen, C.M.; Bibler, N.E.; Beam, D.C.; Ramsey, W.G.; Waters, B.J.

    1992-06-01

    Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced in the Defense Waste Processing Facility (DWPF), poured into stainless steel canisters, and eventually disposed of in a geologic repository. In order to comply with the Waste Acceptance Preliminary Specifications (WAPS), the durability of the glass needs to be measured during production to assure its long term stability and radionuclide release properties. A durability test, designated the Produce Consistency Test (PCT), was developed for DWPF glass in order to meet the WAPS requirements. The response of the PCT procedure was based on extensive testing with glasses of widely different compositions. The PCT was determined to be very reproducible, to yield reliable results rapidly, and to be easily performed in shielded cell facilities with radioactive samples. Version 5.0 of the PCT procedure is attached.

  18. Nuclear waste glass Product Consistency Test (PCT), Version 3. 0

    SciTech Connect

    Jantzen, C.M.; Bibler, N.E.

    1990-11-01

    Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced in the Defense Waste Processing Facility (DWPF), poured into stainless steel canisters, and eventually disposed of in a geologic repository. In order to comply with the Waste Acceptance Preliminary Specifications (WAPS), the durability of the glass needs to be measured during production to assure its long term stability and radionuclide release properties. A durability test, designated the Product Consistency Test (PCT), was developed for DWPF glass in order to meet the WAPS requirements. The response of the PCT procedure was based on extensive testing with glasses of widely different compositions. The PCT was determined to be very reproducible, to yield reliable results rapidly, and to be easily performed in shielded cell facilities with radioactive samples.

  19. Natural glass analogues to alteration of nuclear waste glass: A review and recommendations for further study

    SciTech Connect

    McKenzie, W.F.

    1990-01-01

    The purpose of this report is to review previous work on the weathering of natural glasses; and to make recommendations for further work with respect to studying the alteration of natural glasses as it relates quantifying rates of dissolution. the first task was greatly simplified by the published papers of Jercinovic and Ewing (1987) and Byers, Jercinovic, and Ewing (1987). The second task is obviously the more difficult of the two and the author makes no claim of completeness in this regard. Glasses weather in the natural environment by reacting with aqueous solutions producing a rind of secondary solid phases. It had been proposed by some workers that the thickness of this rind is a function of the age of the glass and thus could be used to estimate glass dissolution rates. However, Jercinovic and Ewing (1987) point out that in general the rind thickness does not correlate with the age of the glass owing to the differences in time of contact with the solution compared to the actual age of the sample. It should be noted that the rate of glass dissolution is also a function of the composition of both the glass and the solution, and the temperature. Quantification of the effects of these parameters (as well as time of contact with the aqueous phase and flow rates) would thus permit a prediction of the consequences of glass-fluid interactions under varying environmental conditions. Defense high- level nuclear waste (DHLW), consisting primarily of liquid and sludge, will be encapsulated by and dispersed in a borosilicate glass before permanent storage in a HLW repository. This glass containing the DHLW serves to dilute the radionuclides and to retard their dispersion into the environment. 318 refs.

  20. Durabiliy of two simulated nuclear waste glasses, a frit glass, and tektite in aqueous solutions: Final report, Volume I

    SciTech Connect

    Hagen, D.A.; Altstetter, C.J.; Brown, S.D.

    1988-05-01

    High level nuclear waste is commonly incorporated into glass for disposal. Therefore the long term aqueous durability of the waste glass is important. The leaching behavior of three simulated nuclear waste glasses (AH10, AH165, and Frit 165) and a natural glass (tektite) were examined using nuclear reaction analysis, leachate solution analysis, and microscopy. The three simulated waste glasses developed hydrated layers which increased in thickness by t/sup /1/2//. The hydrated layer in Frit 165 reached a constant thickness of about one micron. Alkali were preferentially removed from the Frit 165 and AH10. The tektite corroded by slow uniform dissolution. 94 refs., 68 figs., 13 tabs.

  1. Spectroscopic investigations on glasses, glass-ceramics and ceramics developed for nuclear waste immobilization

    NASA Astrophysics Data System (ADS)

    Caurant, D.

    2014-05-01

    Highly radioactive nuclear waste must be immobilized in very durable matrices such as glasses, glass-ceramics and ceramics in order to avoid their dispersion in the biosphere during their radioactivity decay. In this paper, we present various examples of spectroscopic investigations (optical absorption, Raman, NMR, EPR) performed to study the local structure of different kinds of such matrices used or envisaged to immobilize different kinds of radioactive wastes. A particular attention has been paid on the incorporation and the structural role of rare earths—both as fission products and actinide surrogates—in silicate glasses and glass-ceramics. An example of structural study by EPR of a ceramic (hollandite) irradiated by electrons (to simulate the effect of the ?-irradiation of radioactive cesium) is also presented.

  2. Redox of Simulated Nuclear Waste Glass Forming Melts

    SciTech Connect

    Vick, Sara C.; Sundaram, S. K.

    2001-12-01

    Glasses are found in most reduction-oxidation (redox) items that are used everyday; from automobiles to planes. With stability of most glasses, they are being used to store hazardous waste materials. Many elements have different oxidation states and are found in multiple states in glasses. Redox of glasses has significant effect on processing of waste glass melts in melters as well as properties of the waste forms. Nuclear waste glasses generally have complex chemistry (including several redox ions) and form corrosive melts. Basic objective: study the redox of the glasses containing Fe and Ni with square wave voltammetry. A basic simulated frit glass was used for vitrification. The frit composition used was 57.90% SiO2, 17.70% Na2O, 14.70% B2O3, 5.70% Li2O, 2.00% MgO, 1.00% TiO2, 0.50% ZrO2, and 0.50% La2O3. Batch glasses were synthesized and then dopants of Fe2O3 , NiO, and a combination of Fe2O3-NiO were added in 1-wt % amounts. The glass was melted at 1150 C and held for 24 hours. It was poured to the top of a medium sized Pt/Rh crucible and placed in a furnace at 1150 C. The glass powder was allowed to melt for five minutes before the testing apparatus was placed in the melt. The testing apparatus was composed of a Pt/Rh working electrode, Pt/Rh counter electrode, and a Zr/Al reference electrode. The counter electrode is placed in the melt until it is touching the bottom of the crucible creating a closed circuit. Both the reference electrode and working electrode are located half way down the counter electrode. The test showed that melt resistivity was high indicating the amount of conductivity in the melt. Sample melt volume and area of the working electrode were high. Adjusting the crucible size and sizing other electrodes will improve the measurements. Future work: testing NiO glass and Fe2O3-NiO glass to see the interaction between the Fe and the Ni and synthesis of 2 wt %, 3 wt %, and 5-wt % Fe2O3 doped glasses to study effects of Fe concentration.

  3. Redox reaction and foaming in nuclear waste glass melting

    SciTech Connect

    Ryan, J.L.

    1995-08-01

    This document was prepared by Pacific Northwest Laboratory (PNL) and is an attempt to analyze and estimate the effects of feed composition variables and reducing agent variables on the expected chemistry of reactions occurring in the cold cap and in the glass melt in the nuclear waste glass Slurry-fed, joule-heated melters as they might affect foaming during the glass-making process. Numerous redox reactions of waste glass components and potential feed additives, and the effects of other feed variables on these reactions are reviewed with regard to their potential effect on glass foaming. A major emphasis of this report is to examine the potential positive or negative aspects of adjusting feed with formic acid as opposed to other feed modification techniques including but not limited to use of other reducing agents. Feed modification techniques other than the use of reductants that should influence foaming behavior include control of glass melter feed pH through use of nitric acid. They also include partial replacement of sodium salts by lithium salts. This latter action (b) apparently lowers glass viscosity and raises surface tension. This replacement should decrease foaming by decreasing foam stability.

  4. Archaeological analogs and the future of nuclear waste glass

    NASA Astrophysics Data System (ADS)

    Verney-Carron, Aurélie; Gin, Stéphane; Libourel, Guy

    2010-11-01

    Nuclear energy produces long-lived radioactive waste. Glass containment matrices are used to stabilize such waste and to prevent radionuclide dispersion. Over the past few decades, phenomenological models have been developed to predict the long-term behavior of these materials in anticipation of disposal in a deep geological formation. But considering the geological time scales necessary for radioactive decay validating these models is a challenge. Here we show how the validation of the predictive capacity of a mechanistic model applied to archaeological glass alteration bridges the gap between the short-term laboratory data and the long-term evolution of natural system in complex environment. This model applied to nuclear glass provides reliable uncertainties on long-term alteration rates and demonstrates that present models used in the safety calculations are conservative.

  5. Radiation and Thermal Ageing of Nuclear Waste Glass

    SciTech Connect

    Weber, William J

    2014-01-01

    The radioactive decay of fission products and actinides incorporated into nuclear waste glass leads to self-heating and self-radiation effects that may affect the stability, structure and performance of the glass in a closed system. Short-lived fission products cause significant self-heating for the first 600 years. Alpha decay of the actinides leads to self-radiation damage that can be significant after a few hundred years, and over the long time periods of geologic disposal, the accumulation of helium and radiation damage from alpha decay may lead to swelling, microstructural evolution and changes in mechanical properties. Four decades of research on the behavior of nuclear waste glass are reviewed.

  6. Helium solubility in SON68 nuclear waste glass

    SciTech Connect

    Fares, Toby; Peuget, Sylvain; Bouty, Olivier; Broudic, Veronique; Maugeri, Emilio; Bes, Rene; Jegou, Christophe; Chamssedine, Fadel; Sauvage, Thierry; Deschanels, Xavier

    2012-12-15

    Helium behavior in a sodium borosilicate glass (SON68) dedicated to the immobilization of high-level nuclear waste is examined. Two experimental approaches on nonradioactive glass specimens are implemented: pressurized helium infusion experiments and {sup 3}He ion implantation experiments. The temperature variation of helium solubility in SON68 glass was determined and analyzed with the harmonic oscillator model to determine values of the energy of interaction E(0) at the host sites (about -4000 J/mol), the vibration frequency (about 1.7 x 10{sup 11} s{sup -1}), and the density of solubility sites (2.2 x 10{sup 21} sites cm{sup -3}). The implantation experiments show that a non diffusive transport phenomenon (i.e., athermal diffusion) is involved in the material when the helium concentration exceeds 2.3 x 10{sup 21} He cm{sup -3}, and thus probably as soon as it exceeds the density of solubility sites accessible to helium in the glass. We propose that this transport mechanism could be associated with the relaxation of the stress gradient induced by the implanted helium profile, which is favored by the glass damage. Microstructural characterization by TEM and ESEM of glass specimens implanted with high helium concentrations showed a homogeneous microstructure free of bubbles, pores, or cracking at a scale of 10 nm. (authors)

  7. Vanadium and Chromium Redox Behavior in borosilicate Nuclear Waste Glasses

    SciTech Connect

    D McKeown; I Muller; H Gan; Z Feng; C Viragh; I Pegg

    2011-12-31

    X-ray absorption spectroscopy (XAS) was used to characterize vanadium (V) and chromium (Cr) environments in low activity nuclear waste (LAW) glasses synthesized under a variety of redox conditions. V{sub 2}O{sub 5} was added to the melt to improve sulfur incorporation from the waste; however, at sufficiently high concentrations, V increased melt foaming, which lowered melt processing rates. Foaming may be reduced by varying the redox conditions of the melt, while small amounts of Cr are added to reduce melter refractory corrosion. Three parent glasses were studied, where CO-CO{sub 2} mixtures were bubbled through the corresponding melt for increasing time intervals so that a series of redox-adjusted-glasses was synthesized from each parent glass. XAS data indicated that V and Cr behaviors are significantly different in these glasses with respect to the cumulative gas bubbling times: V{sup 4+}/V{sub total} ranges from 8 to 35%, while Cr{sup 3+}/Cr{sub total} can range from 15 to 100% and even to population distributions including Cr{sup 2+}. As Na-content decreased, V, and especially, Cr became more reduced, when comparing equivalent glasses within a series. The Na-poor glass series show possible redox coupling between V and Cr, where V{sup 4+} populations increase after initial bubbling, but as bubbling time increases, V{sup 4+} populations drop to near the level of the parent glass, while Cr becomes more reduced to the point of having increasing Cr{sup 2+} populations.

  8. The Role of Biofilm on the Alteration of Glasses: Example of Basaltic and Nuclear Glasses

    NASA Astrophysics Data System (ADS)

    Aouad, G.; Crovisier, J.; Meyer, J.; Stille, P.; Damidot, D.; Hutchens, E.; Vuilleumier, S.; Geoffroy, V.

    2006-12-01

    It is generally accepted that alterations of rocks and anthropogenic products are not exclusively driven by the interaction with water or mineral aqueous solutions. Organic compounds as well as microorganisms are important in mineral degradation processes, together with secondary mineralization. However, the exact role of biofilms in these processes remains unclear. In our study we tested two materials, a tholeiitic basaltic glass and the reference French nuclear glass SON68 17 LIDC2A2Z1. Experiments were carried out for 19 weeks using a modified soxhlet's device at 25°C. We developed a specific growth medium which allows both the growth of Pseudomonas bacterium and a precise measurement, using ICP-MS, of trace elements solubilized from the two glass materials. The thickness of biofilms, analyzed by confocal laser microscopy was 40?m for both materials. These biofilms are able to efficiently trap most of the glass constituents, some of them being potentially toxic. They also form a protective barrier at the solid/solution interface. Alteration rates were determined at the end of the experiments. The basaltic glass deteriorated with a rate of 18.3 10-4g.m-2.d-1 in biotic conditions and 29.8 10-4g.m-2.d-1 in the sterile system. The nuclear glass had a dissolution rate of 17.6 10^{- 4}g.m-2.d-1 in the biotic experiment and 25.0 10-4g.m-2.d-1in the sterile medium.

  9. Resumption of nuclear glass alteration: State of the art

    NASA Astrophysics Data System (ADS)

    Fournier, Maxime; Gin, Stéphane; Frugier, Pierre

    2014-05-01

    Studies of nuclear glass alteration kinetics have shown that after the beginning of a rate drop due to the approach of silica saturation of the solution and the formation of a passivating layer, a resumption of alteration is possible. This phenomenon corresponding to an acceleration of the glass dissolution rate is systematically associated with the precipitation of zeolites and, to a lesser extent, calcium silicate hydrates. Secondary phases which precipitate from the major glass network-forming elements (Si, Al) strongly impact the dissolution kinetics. The literature data are generally consistent and the results are reproducible, showing that the resumption of alteration is observed at high pH, temperature, and S/V ratio during laboratory experiments. The studies also show that the resumption of alteration is strongly dependent on the composition of the glass and the leaching solutions. The wide range of glass compositions studied (about 60 glasses in the articles reviewed) and the variable test conditions (temperature, pH, and solution composition) make it extremely difficult to compare and compile the data, or to decorrelate the effects of the composition on the time before the resumption of alteration and on its magnitude. The observations to date have led to a proposed macroscopic mechanism based on the loss of the passivating properties of the alteration layer after consumption of a fraction of the network-forming elements by precipitation of zeolites. No multiscale mechanistic approach exists, however, to account for the nucleation and growth of zeolites at the expense of the glass. For example, the effect of aluminum in the gel or in solution on the glass alteration kinetics is not sufficiently understood today. Although thermodynamic models have been proposed to delimit the ranges of glass compositions subject to a resumption of alteration, their development is hampered by inadequate knowledge of the newly formed phases and their nucleation-growth mechanism, and by gaps in the thermodynamic databases. Their development is also constrained by the capability of the models to take Si-Al-Ca interactions into account in the alteration gels.

  10. MILLIMETER-WAVE MONITORING OF NUCLEAR WASTE GLASS MELTS - AN OVERVIEW

    EPA Science Inventory

    Molten glass characteristics of temperature, resistivity, and viscosity can be monitored reliably in the high temperature and chemically corrosive environment of nuclear waste glass melters using millimeter-wave sensor technology. Millimeter-waves are ideally suited for such meas...

  11. CORROSION OF NUCLEAR WASTE GLASSES IN NON-SATURATED CONDITIONS: TIME-TEMPERATURE BEHAVIOUR

    E-print Network

    Sheffield, University of

    analysis is based on corrosion behaviour of identical radioactive high-sodium content borosilicate glass waste. Some tonnes of this glass were produced in the 1980-s using radioactive waste from the Kursk NPPCORROSION OF NUCLEAR WASTE GLASSES IN NON-SATURATED CONDITIONS: TIME-TEMPERATURE BEHAVIOUR Michael

  12. Lead iron phosphate glass as a containment medium for disposal of high-level nuclear waste

    DOEpatents

    Boatner, Lynn A. (Oak Ridge, TN); Sales, Brian C. (Oak Ridge, TN)

    1989-01-01

    Lead-iron phosphate glasses containing a high level of Fe.sub.2 O.sub.3 for use as a storage medium for high-level radioactive nuclear waste. By combining lead-iron phosphate glass with various types of simulated high-level nuclear waste, a highly corrosion resistant, homogeneous, easily processed glass can be formed. For corroding solutions at 90.degree. C., with solution pH values in the range between 5 and 9, the corrosion rate of the lead-iron phosphate nuclear waste glass is at least 10.sup.2 to 10.sup.3 times lower than the corrosion rate of a comparable borosilicate nuclear waste glass. The presence of Fe.sub.2 O.sub.3 in forming the lead-iron phosphate glass is critical. Lead-iron phosphate nuclear waste glass can be prepared at temperatures as low as 800.degree. C., since they exhibit very low melt viscosities in the 800.degree. to 1050.degree. C. temperature range. These waste-loaded glasses do not readily devitrify at temperatures as high as 550.degree. C. and are not adversely affected by large doses of gamma radiation in H.sub.2 O at 135.degree. C. The lead-iron phosphate waste glasses can be prepared with minimal modification of the technology developed for processing borosilicate glass nuclear wasteforms.

  13. Glass former composition and method for immobilizing nuclear waste using the same

    SciTech Connect

    Cadoff, L.H.; Smith-Magowan, D.B.

    1988-07-26

    In a method of immobilizing nuclear waste in glass where a glass forming composition is prepared which comprises a slurry of alkoxide glass forming components containing hydrolyzed glass-forming silicon compound in a liquid carrier, where the composition is heated at an elevated temperature to reduce the volume thereof and provide a glass former, the glass former is mixed with nuclear waste at up to 500/sup 0/C, and the resultant mixture is melted at about 700/sup 0/-1500/sup 0/C, the improvement is described which makes the composition resistant to coagulation comprising using the hydrolyzed glass-forming silicon compound in the form of particulate solids having a particle size of 0.1-0.7 micrometer in diameter, so that the liquid carrier is substantially free of the dissolved hydrolyzed glass-forming silicon compound.

  14. Development of glass vitrification at SRL as a waste treatment technique for nuclear weapon components

    SciTech Connect

    Coleman, J.T.; Bickford, D.F.

    1991-12-31

    This report discusses the development of vitrification for the waste treatment of nuclear weapons components at the Savannah River Site. Preliminary testing of surrogate nuclear weapon electronic waste shows that glass vitrification is a viable, robust treatment method.

  15. Development of glass vitrification at SRL as a waste treatment technique for nuclear weapon components

    SciTech Connect

    Coleman, J.T.; Bickford, D.F.

    1991-01-01

    This report discusses the development of vitrification for the waste treatment of nuclear weapons components at the Savannah River Site. Preliminary testing of surrogate nuclear weapon electronic waste shows that glass vitrification is a viable, robust treatment method.

  16. An Investigation into the Oxidation State of Molybdenum in Simplified High Level Nuclear Waste Glass Compositions

    E-print Network

    Sheffield, University of

    originating from the reprocessing of spent nuclear fuel. Experiments using simulated nuclear waste streams. INTRODUCTION Alkali borosilicate glasses are used by British Nuclear Fuels (BNFL) to vitrify HLW raffinatesAn Investigation into the Oxidation State of Molybdenum in Simplified High Level Nuclear Waste

  17. Glass former composition and method for immobilizing nuclear waste using the same

    DOEpatents

    Cadoff, Laurence H. (Wilkins Township, Allegheny County, PA); Smith-Magowan, David B. (Washington, DC)

    1988-01-01

    An alkoxide glass former composition has silica-containing constituents present as solid particulates of a particle size of 0.1 to 0.7 micrometers in diameter in a liquid carrier phase substantially free of dissolved silica. The glass former slurry is resistant to coagulation and may contain other glass former metal constituents. The immobilization of nuclear waste employs the described glass former by heating the same to reduce the volume, mixing the same with the waste, and melting the resultant mixture to encapsulate the waste in the resultant glass.

  18. Determination of alpha dose rate profile at the HLW nuclear glass/water interface

    NASA Astrophysics Data System (ADS)

    Mougnaud, S.; Tribet, M.; Rolland, S.; Renault, J.-P.; Jégou, C.

    2015-07-01

    Alpha irradiation and radiolysis can affect the alteration behavior of High Level Waste (HLW) nuclear glasses. In this study, the way the energy of alpha particles, emitted by a typical HLW glass, is deposited in water at the glass/water interface is investigated, with the aim of better characterizing the dose deposition at the glass/water interface during water-induced leaching mechanisms. A simplified chemical composition was considered for the nuclear glass under study, wherein the dose rate is about 140 Gy/h. The MCNPX calculation code was used to calculate alpha dose rate and alpha particle flux profiles at the glass/water interface in different systems: a single glass grain in water, a glass powder in water and a water-filled ideal crack in a glass package. Dose rate decreases within glass and in water as distance to the center of the grain increases. A general model has been proposed to fit a dose rate profile in water and in glass from values for dose rate in glass bulk, alpha range in water and linear energy transfer considerations. The glass powder simulation showed that there was systematic overlapping of radiation fields for neighboring glass grains, but the water dose rate always remained lower than the bulk value. Finally, for typical ideal cracks in a glass matrix, an overlapping of irradiation fields was observed while the crack aperture was lower than twice the alpha range in water. This led to significant values for the alpha dose rate within the crack volume, as long as the aperture remained lower than 60 ?m.

  19. Nano-Continuum Modeling of a Nuclear Glass Specimen Altered for 25 Years

    SciTech Connect

    Steefel, Carl

    2014-01-06

    The purpose of this contribution is to report on preliminary nano-continuum scale modeling of nuclear waste glass corrosion. The focus of the modeling is an experiment involving a French glass SON68 specimen leached for 25 years in a granitic environment. In this report, we focus on capturing the nano-scale concentration profiles. We use a high resolution continuum model with a constant grid spacing of 1 nanometer to investigate the glass corrosion mechanisms.

  20. ALKALI/ AKALINE-EARTH CONTENT EFFECTS ON PROPERTIES OF HIGH-ALUMINA NUCLEAR WASTE GLASSES

    SciTech Connect

    McCloy, John S.; Rodriguez, Carmen P.; Windisch, Charles F.; Leslie, Clifford J.; Schweiger, Michael J.; Riley, Brian J.; Vienna, John D.

    2010-10-01

    A series of high alumina (>20 mass %) borosilicate glasses have been made and characterized based on the assumption that the primary modifier cation field strength plays a significant role in mediating glass structure of nuclear waste glasses. Any crystallization upon quenching or after heat treatment at 950 °C for 24 hours was identified and quantified by X-ray diffraction. Particular note was take of any aluminosilicates formed, such as those in the nepheline group (MAlSiO4 where M=K, Na, Li), as these remove multiple glass-formers from the network upon crystallization. The relative roles of potassium, sodium, lithium, calcium, and magnesium on glass structure and crystallization in high alumina glasses were explored using Raman and infrared vibrational spectroscopy. Strong evidence was found for the importance of 4 membered rings in glasses with 10 mol % alkaline earths (Ca, Mg).

  1. ASSESSMENT OF NEPHELINE PRECIPITATION IN NUCLEAR WASTE GLASS VIA THERMOCHEMICAL MODELING

    EPA Science Inventory

    A thermochemical representation of the Na-Al-Si-B-O system relevant for nuclear waste glass has been developed based on the associate species approach for the glass solution phase. Thermochemical data were assessed and associate species data determined for binary and ternary sub...

  2. The effect of chromium oxide on the properties of simulated nuclear waste glasses

    SciTech Connect

    Vojtech, O.; Sussmilch, J.; Urbanec, Z.

    1996-02-01

    A study of the effect of chromium on the properties of selected glasses was performed in the frame of a Contract between Battelle, Pacific Northwest Laboratories and Nuclear Research Institute, ReZ. In the period from July 1994 to June 1995 two borosilicate glasses of special composition were prepared according to the PNL procedure and their physical and structural characteristics of glasses were studied. This Final Report contains a vast documentation on the properties of all glasses studied. For the preparation of the respective technology more detailed study of physico-chemical properties and crystallinity of investigated systems would be desirable.

  3. Characterization of high-level nuclear waste glass using magnetic measurements

    SciTech Connect

    Senftle, F.E.; Thorpe, A.N.; Grant, J.R.; Barkatt, A.

    1994-12-31

    Magnetic measurements constitute a promising method for the characterization of nuclear waste glasses in view of their simplicity and small sample weight requirements. Initial studies of simulated high-level waste glasses show that the Curie constant is generally a useful indicator of the Fe{sup 2+}:Fe{sup 3+} ratio. Glasses produced by air-cooling in large vessels show systematic deviations between experimental and calcined values, which are indicative of the presence of small amounts of crystalline iron-containing phases. Most of the iron in these phases becomes dissolved in the glass upon re-heating and more rapid quenching. The studies further show that upon leaching the glass in water some of the iron in the surface regions of the glass is converted to a form which has high temperature-independent magnetic susceptibility.

  4. Effect of alpha radiation on the leaching behaviour of nuclear glass

    NASA Astrophysics Data System (ADS)

    Peuget, S.; Broudic, V.; Jégou, C.; Frugier, P.; Roudil, D.; Deschanels, X.; Rabiller, H.; Noel, P. Y.

    2007-05-01

    The behaviour of nuclear glass subjected to the stress loading expected in a repository must be investigated to demonstrate that it is capable of durably confining radioactive elements. Because of the minor actinides (Np, Am, Cm) contained in the glass, alpha radiation is one of the stresses that could affect the glass properties. This study focuses on the effect of alpha radiation on the chemical reactivity of R7T7 glass with pure water. Various glass samples doped with 237Np, 238Pu, 239Pu, 241Am or 244Cm were fabricated in the CEA facilities at Marcoule. The content of each actinide was adjusted to cover a range of alpha activity varying from 105 to 1011 Bq g-1 and a range of alpha decay doses up to 4 × 1018 g-1. Inactive glass samples were also subjected to multiple-energy external irradiation by heavy ions to simulate the impact of alpha damage. The initial glass alteration rates, which reflect the chemical reactivity between the glass matrix and pure water, were determined by standard Soxhlet tests together with analysis of the leaching solution by ICP-AES. Comparing the glass leaching rates is indicative of the impact of alpha radiation. The experimental data show that neither the alpha activity nor the alpha decay dose has a significant impact on the initial alteration rate of R7T7 glass.

  5. Simulation of Self-Irradiation of High-Sodium Content Nuclear Waste Glasses

    SciTech Connect

    Pankov, Alexey S.; Ojovan, Michael I.; Batyukhnova, Olga G.

    2007-07-01

    Alkali-borosilicate glasses are widely used in nuclear industry as a matrix for immobilisation of hazardous radioactive wastes. Durability or corrosion resistance of these glasses is one of key parameters in waste storage and disposal safety. It is influenced by many factors such as composition of glass and surrounding media, temperature, time and so on. As these glasses contain radioactive elements most of their properties including corrosion resistance are also impacted by self-irradiation. The effect of external gamma-irradiation on the short-term (up to 27 days) dissolution of waste borosilicate glasses at moderate temperatures (30 deg. to 60 deg. C) was studied. The glasses studied were Magnox Waste glass used for immobilisation of HLW in UK, and K-26 glass used in Russia for ILW immobilisation. Glass samples were irradiated under {gamma}-source (Co-60) up to doses 1 and 11 MGy. Normalised rates of elemental release and activation energy of release were measured for Na, Li, Ca, Mg, B, Si and Mo before and after irradiation. Irradiation up to 1 MGy results in increase of leaching rate of almost all elements from both MW and K-26 with the exception of Na release from MW glass. Further irradiation up to a dose of 11 MGy leads to the decrease of elemental release rates to nearly initial value. Another effect of irradiation is increase of activation energies of elemental release. (authors)

  6. A comparison of the performance of nuclear waste glasses by modeling

    SciTech Connect

    Grambow, B.; Strachan, D.M.

    1988-12-01

    Through a combination of data collection and computer modeling, the dissolution mechanism of nuclear waste glasses has been investigated and more clearly defined. Glass dissolution can be described as a dissolution/precipitation process in which glass dissolves in aqueous solution and solids precipitate as the solubility products are exceeded. The dissolution process is controlled by activity of the rate-limiting specie H/sub 4/SiO/sub 4/. As a concentration of H/sub 4/SiO/sub 4/ increases, the rate of dissolution decreases until a final reaction rate is reached. Between the forward reaction rate (early time) and final reaction rate (very long time), glasses may exhibit an intermediate root time dependence caused by a transport resistance for the diffusion of H/sub 4/SiO/sub 4/ within the gel layer on the glass surface. In this report, three glasses are studied: JSS-A, PNL 76-68, and SRL-131. Data from static and dynamic leach tests are assembled, plotted, and successfully modeled. The kinetic parameters for these glasses are reported. With four parameters derived from experiments for each glass, the model can be used to calculate the effects of changes in the initial composition of the water contacting the glass. The effects of convective flow can also be modeled. Furthermore, glasses of different compositions can be readily compared. 49 refs., 27 figs., 5 tabs.

  7. Fracture during cooling of cast borosilicate glass containing nuclear wastes

    SciTech Connect

    Smith, P.K.; Baxter, C.A.

    1981-09-01

    Procedures and techniques were evaluated to mitigate thermal stress fracture in waste glass as the glass cools after casting. The two principal causes of fracture identified in small-scale testing are internal thermal stresses arising from excessive thermal gradients when cooled too fast, and shear fracturing in the surface of the glass because the stainless steel canister shrinks faster than the glass on cooling. Acoustic emission and ceramographic techniques were used to outline an annealing schedule that requires at least three weeks of controlled cooling below 550/sup 0/C to avoid excessive thermal gradients and corresponding stresses. Fracture arising from canister interactions cannot be relieved by slow cooling, but can be eliminated for stainless steel canisters by using ceramic paper, ceramic or graphite paste linings, or by choosing a canister material with a thermal expansion coefficient comparable to, or less than, that of the glass.

  8. Corrosion of synthesized glasses and glazes as analogs for nuclear waste glass degradation

    SciTech Connect

    Vandiver, P.B.

    1994-12-31

    Synthesized glasses provide an opportunity to study natural corrosion processes which are intermediate in time span between geological examples of natural glasses, such as obsidians and tektites, and relatively short term laboratory tests lasting a few hours to several decades. In addition, synthesized glasses can usually be tracked to particular archaeological find sites with known dates of production and often burial. Environmental conditions are routinely measured at archaeological sites as a part of the excavation-process, such that information is available on the yearly cycling of temperature and relative humidity, sometimes at the depth at which the artifact was found. Whether the artifacts were excavated in an air enclosure, such as a tomb, or in the soil can also be reconstructed, such that one can determine whether aqueous or atmospheric corrosion was involved in the degradation process. For instance, so-called {open_quotes}Roman glass{close_quotes} may span a time period of production of 800 years and a geographical range from Germany to North Africa and from Britain to Afghanistan. One example is the storage during World War II of glass from the British Museum in underground metro stations. Some of these glasses have been in collections for over 100 years. Thus, populations of glasses can be chosen for experimentation which compare variations in bulk composition, dopants, microstructure, heat treatment, ground vs. fire polished surfaces, aqueous vs. atmospheric corrosion, geographic, geological as well as recent storage conditions. Glasses in museums are generally considered to have had their corrosion arrested and be stable because changes in visual appearance are not obvious. However, if we attempt to measure the range of surface water content in these glasses using Fourier transform infrared analysis, a considerable variability is found, as shown.

  9. THE IMPACT OF KINETICS ON NEPHELINE FORMATION IN NUCLEAR WASTE GLASSES

    SciTech Connect

    Amoroso, J.

    2011-03-07

    Sixteen glass compositions were selected to study the potential impacts of the kinetics of nepheline formation in high-level nuclear waste (HLW) glass. The chosen compositions encompassed a relatively large nepheline discriminator (ND) range, 0.40-0.66, and included a relatively broad range, and amount of, constituents including high aluminum and high boron concentrations. All glasses were fabricated in the laboratory and subsequently exposed to six different cooling treatments. The cooling treatments consisted of three 'stepped' profiles and their corresponding 'smooth' profiles. Included in the cooling treatment was the Defense Waste Processing Facility (DWPF) canister centerline cooling (CCC) profile in addition to a 'faster' and a 'slower' total cooling line. After quenching and heat treating, x-ray diffraction confirmed the type and amount of any resultant crystallization. The target compositions were shown to be consistent with the measured compositions. Two quenched glasses and several treated glasses exhibited minor amounts of spinel and spinel-like phases. Nepheline was not observed in any of the quenched glasses but was observed in many of the treated glasses. The amount of nepheline ranged from approximately 2wt% to 30wt% for samples cooled over shorter times and longer times respectively. Differences were observed in the amount of nepheline crystallization after smooth and stepped cooling and increased with total cooling time. In some glasses, nepheline crystallization appeared to be directly proportional to total cooling time while the total amount of nepheline crystallization varied, suggesting that the nepheline crystallization rate was independent of (or at least faster than) cooling rate but, varied depending on the glass composition. On the contrary, in another glass, nepheline crystallization appeared to be inversely proportional to cooling rate. The high alumina glasses, predicted to form nepheline according to the ND, did not precipitate nepheline. Additionally, analysis from different regions of treated glasses indicated that nepheline nucleation and growth occurs at the glass/crucible and glass/atmosphere interfaces. Furthermore, the measured amount of non-nepheline phases appeared independent of the sampling region. It is postulated that crucible-scale methods used to heat treat HLW glass, such as the CCC method, artificially induce nepheline formation in the glass. The results of this study suggest nepheline kinetics can vary significantly depending on glass composition and, more importantly, glasses fabricated using current DWPF conditions are potentially susceptible to the impact of nepheline kinetics. This report summarizes the supporting research and provides the basis for continued research on nepheline kinetics and its effects on HLW glasses.

  10. Production and dissolution of nuclear explosive melt glasses at underground test sites in the Pacific Region

    SciTech Connect

    Bourcier, W.L.; Smith, D.K.

    1998-11-06

    From 1975 to 1996 the French detonated 140 underground nuclear explosions beneath the atolls of Mururoa and Fangataufa in the South Pacific; from 1965 to 1971 the United States detonated three high yield nuclear tests beneath Amchitka Island in the Aleutian chain. Approximately 800 metric tons of basalt is melted per kiloton of nuclear yield; almost lo7 metric tons of basalt were melted in these tests. Long-lived and toxic radionuclides are partitioned into the melt glass at the time of explosion and are released by dissolution with seawater under saturated conditions. A glass dissolution model predicts that nuclear melt glasses at these sites will dissolve in lo6 to lo7 yea

  11. EELS Spectrum Imaging and Tomography Studies of Simulated Nuclear Waste Glasses

    SciTech Connect

    Yang, Guang; Saghi, Zineb; Xu, Xiaojing; Hand, Russell; Moebus, Guenter

    2007-07-01

    Electron energy loss spectroscopy (EELS) fine structure is a powerful technique for analyzing oxidation levels of rare-earth oxides and coordination numbers in glasses and ceramics, especially for boron. To exploit the unique advantage of EELS over x-ray absorption spectroscopy (XAS)/x-ray absorption near edge structure (XANES), namely nm-scale spatial resolution, EELS spectrum imaging across precipitates in glasses has been employed to detect lateral changes of EELS fine structure. Alkali borosilicate (ABS) glasses doped with Cr{sub 2}O{sub 3}, CeO{sub 2} and ZrO{sub 2} or Fe{sub 2}O{sub 3} were melted to simulate high level radionuclide immobilization glasses. Precipitates with diameter in the range of {approx}20 nm to {approx}500 nm were found homogeneously distributed in the glasses. Ce valence was found to be mainly +3 in the glass matrix, and +4 in crystalline precipitates, while some amorphous particles show +3 as well. Another powerful TEM technique for the analysis of glass-nano-composites is electron tomography, as it is up to now the only technique for the three-dimensional reconstruction of nano-particles. A 3D reconstructed nuclear waste glass is presented in this paper by using a tilt series of ADF STEM images covering a glass fragment of {approx}3{mu}m field of view containing several tens of nano-particles distributed throughout its volume. (authors)

  12. Overview of chemical modeling of nuclear waste glass dissolution

    SciTech Connect

    Bourcier, W.L.

    1991-02-01

    Glass dissolution takes place through metal leaching and hydration of the glass surface accompanied by development of alternation layers of varying crystallinity. The reaction which controls the long-term glass dissolution rate appears to be surface layer dissolution. This reaction is reversible because the buildup of dissolved species in solution slows the dissolution rate due to a decreased dissolution affinity. Glass dissolution rates are therefore highly dependent on silica concentrations in solution because silica is the major component of the alteration layer. Chemical modeling of glass dissolution using reaction path computer codes has successfully been applied to short term experimental tests and used to predict long-term repository performance. Current problems and limitations of the models include a poorly defined long-term glass dissolution mechanism, the use of model parameters determined from the same experiments that the model is used to predict, and the lack of sufficient validation of key assumptions in the modeling approach. Work is in progress that addresses these issues. 41 refs., 7 figs., 2 tabs.

  13. Progress toward bridging from atomistic to continuum modeling to predict nuclear waste glass dissolution.

    SciTech Connect

    Zapol, Peter; Bourg, Ian; Criscenti, Louise Jacqueline; Steefel, Carl I.; Schultz, Peter Andrew

    2011-10-01

    This report summarizes research performed for the Nuclear Energy Advanced Modeling and Simulation (NEAMS) Subcontinuum and Upscaling Task. The work conducted focused on developing a roadmap to include molecular scale, mechanistic information in continuum-scale models of nuclear waste glass dissolution. This information is derived from molecular-scale modeling efforts that are validated through comparison with experimental data. In addition to developing a master plan to incorporate a subcontinuum mechanistic understanding of glass dissolution into continuum models, methods were developed to generate constitutive dissolution rate expressions from quantum calculations, force field models were selected to generate multicomponent glass structures and gel layers, classical molecular modeling was used to study diffusion through nanopores analogous to those in the interfacial gel layer, and a micro-continuum model (K{mu}C) was developed to study coupled diffusion and reaction at the glass-gel-solution interface.

  14. Nuclear waste glass product consistency test (PCT), Version 5.0. Revision 2

    SciTech Connect

    Jantzen, C.M.; Bibler, N.E.; Beam, D.C.; Ramsey, W.G.; Waters, B.J.

    1992-06-01

    Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced in the Defense Waste Processing Facility (DWPF), poured into stainless steel canisters, and eventually disposed of in a geologic repository. In order to comply with the Waste Acceptance Preliminary Specifications (WAPS), the durability of the glass needs to be measured during production to assure its long term stability and radionuclide release properties. A durability test, designated the Produce Consistency Test (PCT), was developed for DWPF glass in order to meet the WAPS requirements. The response of the PCT procedure was based on extensive testing with glasses of widely different compositions. The PCT was determined to be very reproducible, to yield reliable results rapidly, and to be easily performed in shielded cell facilities with radioactive samples. Version 5.0 of the PCT procedure is attached.

  15. Measurement of leaching from simulated nuclear-waste glass using radiotracers

    SciTech Connect

    Bates, J.K.; Jardine, L.J.; Steindler, M.J.

    1982-09-01

    The use of radiotracer spiking as a method of measuring the leaching from simulated nuclear-waste glass is shown to give results comparable with other analytical detection methods. The leaching behavior of /sup 85/Sr, /sup 106/Ru, /sup 133/Ba, /sup 137/Cs, /sup 141/Ce, /sup 152/Eu, and other isotopes is measured for several defense waste glasses. These tests show that radiotracer spiking is a sensitive, multielement technique that can provide leaching data, for actual waste elements, that are difficult to obtain by other methods. Additionally, a detailed procedure is described that allows spiked glass to be prepared with a suitable distribution of radionuclides.

  16. An international initiative on long-term behavior of high-level nuclear waste glass

    SciTech Connect

    Gin, Stephane; Criscenti, Louise J.; Ebert, W. L.; Ferrand, Karine; Geisler, Thorsten; Harrison, Mike T.; Inagaki, Yaohiro; Mitsui, Seiichiro; Mueller, Karl T.; Marra, James C.; Pantano, Carlo G.; Pierce, Eric M.; Ryan, Joseph V.; Schofield, James M.; Steefel, Carl I.; Vienna, John D.

    2013-06-01

    Nations producing borosilicate glass as an immobilization material for radioactive wastes resulting from spent nuclear fuel reprocessing have reinforced scientific collaboration to obtain consensus on mechanisms controlling the long-term dissolution rate of glass. This goal is deemed to be crucial for the development of reliable performance assessment models for geological disposal. The collaborating laboratories all conduct fundamental and/or applied research with modern materials science techniques. The paper briefly reviews the radioactive waste vitrification programmes of the six participant nations and summarizes the state-of-the-art of glass corrosion science, emphasizing common scientific needs and justifications for on-going initiatives.

  17. Dynamic Time Scales in Colored Glass Nuclear Matter

    E-print Network

    V. Parihar; A. Widom; Y. N. Srivastava

    2006-11-16

    In Ultra high energy collisions, the concept of a glass law is invoked in the framework of 'low tension' QCD strings. It is shown that the excitation of QCD strings at low energy has a negative temperature and at high energy has a positive temperature always higher than the Hagedorn temperature, T_H. Very high energy strings T->T_H + 0+ move very slowly as a viscous melted glass with very high viscosity. However, in a very short collision time, it is difficult to transfer the initial collision kinetic energy into the internal energy of a few strings. The low energy strings at high T>>T_H have a low viscosity giving rise to an almost perfect fluid. The role of strings in a nucleus is closely analogous to the role of polymer chains in some viscous glass beads.

  18. Deformation mechanisms during nanoindentation of sodium borosilicate glasses of nuclear interest

    SciTech Connect

    Kilymis, D. A.; Delaye, J.-M.

    2014-07-07

    In this paper we analyze results of Molecular Dynamics simulations of Vickers nanoindentation, performed for sodium borosilicate glasses of interest in the nuclear industry. Three glasses have been studied in their pristine form, as well as a disordered one that is analogous to the real irradiated glass. We focused in the behavior of the glass during the nanoindentation in order to reveal the mechanisms of deformation and how they are affected by microstructural characteristics. Results have shown a strong dependence on the SiO{sub 2} content of the glass, which promotes densification due to the open structure of SiO{sub 4} tetrahedra and also due to the strength of Si-O bonds. Densification for the glasses is primarily expressed by the relative decrease of the Si-O-Si and Si-O-B angles, indicating rotation of the structural units and decrease of free volume. The increase of alkali content on the other hand results to higher plasticity of the matrix and increased shear flow. The most important effect on the deformation mechanism of the disordered glasses is that of the highly depolymerized network that will also induce shear flow and, in combination with the increased free volume, will result in the decreased hardness of these glasses, as has been previously observed.

  19. The role of natural glasses as analogues in projecting the long-term alteration of high-level nuclear waste glasses: Part 1

    SciTech Connect

    Mazer, J.J.

    1993-12-31

    The common observation of glasses persisting in natural environments for long periods of time (up to tens of millions of years) provides compelling evidence that these materials can be kinetically stable in a variety of subsurface environments. This paper reviews how natural and historical synthesized glasses can be employed as natural analogues for understanding and projecting the long-term alteration of high-level nuclear waste glasses. The corrosion of basaltic glass results in many of the same alteration features found in laboratory testing of the corrosion of high-level radioactive waste glasses. Evidence has also been found indicating similarities in the rate controlling processes, such as the effects of silica concentration on corrosion in groundwater and in laboratory leachates. Naturally altered rhyolitic glasses and tektites provide additional evidence that can be used to constrain estimates of long-term waste glass alteration. When reacted under conditions where water is plentiful, the corrosion for these glasses is dominated by network hydrolysis, while the corrosion is dominated by molecular water diffusion and secondary mineral formation under conditions where water contact is intermittent or where water is relatively scarce. Synthesized glasses that have been naturally altered result in alkali-depleted alteration features that are similar to those found for natural glasses and for nuclear waste glasses. The characteristics of these alteration features appear to be dependent on the alteration conditions which affect the dominant reaction processes during weathering. In all cases, care must be taken to ensure that the information being provided by natural analogues is related to nuclear waste glass corrosion in a clear and meaningful way.

  20. Solid-State NMR Examination of Alteration Layers on a Nuclear Waste Glasses

    SciTech Connect

    Murphy, Kelly A.; Washton, Nancy M.; Ryan, Joseph V.; Pantano, Carlo G.; Mueller, Karl T.

    2013-06-01

    Solid-state NMR is a powerful tool for probing the role and significance of alteration layers in determining the kinetics for the corrosion of nuclear waste glass. NMR methods are used to probe the chemical structure of the alteration layers to elucidate information about their chemical complexity, leading to increased insight into the mechanism of altered layer formation. Two glass compositions were examined in this study: a glass preliminarily designed for nuclear waste immobilization (called AFCI) and a simplified version of this AFCI glass (which we call SA1R). Powdered glasses with controlled and known particles sizes were corroded at 90 °C for periods of one and five months with a surface-area to solution-volume ratio of 100,000 m-1. 1H-29Si CP-CPMG MAS NMR, 1H-27Al CP-MAS NMR, 1H-11B CP-MAS NMR, and 1H-23Na CP-MAS NMR experiments provide isolated structural information about the alteration layers, which differ in structure from that of the pristine glass. Both glasses studied here develop alteration layers composed primarily of [IV]Si species. Aluminum is also retained in the alteration layers, perhaps facilitated by the observed increase in coordination from [IV]Al to [VI]Al, which correlates with a loss of charge balancing cations. 1H-11B CP-MAS NMR observations indicated a retention of boron in hydrated glass layers, which has not been characterized by previous work. For the AFCI glass, secondary phase formation begins during the corrosion times considered here, and these neophases are detected within the alteration layers. We identify precursor phases as crystalline sodium metasilicates. An important finding is that layer thickness depends on the length of the initial alteration stages and varies only with respect to silicon species during the residual rate regime.

  1. AN APPROACH TO THERMOCHEMICAL MODELING OF NUCLEAR WASTE GLASS

    EPA Science Inventory

    This initial work is aimed at developing a basic understanding of the phase equilibria and solid solution behavior of the constituents of waste glass. Current, experimentally determined values are less than desirable since they depend on measurement of the leach rate under non-r...

  2. Lead-iron phosphate glass as a containment medium for the disposal of high-level nuclear wastes

    DOEpatents

    Boatner, L.A.; Sales, B.C.

    1984-04-11

    Disclosed are lead-iron phosphate glasses containing a high level of Fe/sub 2/O/sub 3/ for use as a storage medium for high-level radioactive nuclear waste. By combining lead-iron phosphate glass with various types of simulated high-level nuclear waste

  3. AN ALTERNATIVE HOST MATRIX BASED ON IRON PHOSPHATE GLASSES FOR THE VITRIFICATION OF SPECIALIZED NUCLEAR WASTE FORMS

    EPA Science Inventory

    Borosilicate glass is the only material currently approved and being used to vitrify high level nuclear waste. Unfortunately, many high level nuclear waste feeds in the U.S. contain components which are chemically incompatible with borosilicate glasses. Current plans call for vit...

  4. Comprehensive data base of high-level nuclear waste glasses: September 1987 status report: Volume 1, Discussion and glass durability data

    SciTech Connect

    Kindle, C.H.; Kreiter, M.R.

    1987-12-01

    The Materials Characterization Center (MCC) at Pacific Northwest Laboratory is assembling a comprehensive data base (CDB) of experimental data collected for high-level nuclear waste package components. Data collected throughout the world are included in the data base; current emphasis is on waste glasses and their properties. The goal is to provide a data base of properties and compositions and an analysis of dominant property trends as a function of composition. This data base is a resource that nuclear waste producers, disposers, and regulators can use to compare properties of a particular high-level nuclear waste glass product with the properties of other glasses of similar compositions. Researchers may use the data base to guide experimental tests to fill gaps in the available knowledge or to refine empirical models. The data are incorporated into a computerized data base that will allow the data to be extracted based on, for example, glass composition or test duration. 3 figs.

  5. Borosilicate and lead silicate glass matrix composites containing pyrochlore phases for nuclear waste encapsulation

    NASA Astrophysics Data System (ADS)

    Boccaccini, A. R.; Bernardo, E.; Blain, L.; Boccaccini, D. N.

    2004-05-01

    Glass matrix composites intended for the immobilisation of plutonium bearing nuclear legacy waste have been manufactured. Two different matrices, a soda borosilicate glass and a lead silicate glass, are proposed for encapsulating lanthanum and gadolinium zirconates having pyrochlore crystalline structure. The fabrication of the composites involves powder mixing followed by cold pressing and pressureless sintering or hot-pressing at relatively low temperatures (<620 °C). The hot-pressing route is found to be the most convenient, since it leads to relatively high densification even with substantial loading of pyrochlore phase (40 vol.%). The absence of microcracks, due to the close matching of thermal expansion coefficients of the composite constituents, together with the strong pyrochlore particle/glass matrix interfacial bonding, suggests that the composites have good mechanical properties. The innovative introduction of gadolinium zirconate in a lead silicate matrix represents an attractive approach, since the composites reach reasonably high densities both by pressureless sintering and hot-pressing.

  6. Multicomponent leach tests in Standard Canadian Shield Saline Solution on glasses containing simulated nuclear waste

    SciTech Connect

    Heimann, R.B.; Wood, D.D.; Hamon, R.F.

    1984-01-01

    Leaching experiments on borosilicate glass frit and simulated nuclear waste glasses were performed as a preliminary to leaching experiments on glasses incorporating radioactive waste. The experimental design included (1) simulated waste glass, (2) ASTM Grade-2 titanium container material, (3) clay buffer material, (4) Standard Canadian Shield Saline Solution, and (5) granitic rock. Cumulative fractions of release for boron were determined, as well as the solution concentrations of silicon, iron, strontium and cesium. The leach rates for boron after 28 d were approximately 5 x 10/sup -6/ kg x m/sup -2/ x s/sup -1/ in Hastelloy vessels. There is an apparently strong relationship between the clay/groundwater ratio, the concentration of iron in the solution, and the concentrations of silicon, strontium, and cesium.

  7. Current Understanding and Remaining Challenges in Modeling Long-Term Degradation of Borosilicate Nuclear Waste Glasses

    SciTech Connect

    Vienna, John D.; Ryan, Joseph V.; Gin, Stephane; Inagaki, Yaohiro

    2013-12-01

    Chemical durability is not a single material property that can be uniquely measured. Instead it is the response to a host of coupled material and environmental processes whose rates are estimated by a combination of theory, experiment, and modeling. High-level nuclear waste (HLW) glass is perhaps the most studied of any material yet there remain significant technical gaps regarding their chemical durability. The phenomena affecting the long-term performance of HLW glasses in their disposal environment include surface reactions, transport properties to and from the reacting glass surface, and ion exchange between the solid glass and the surrounding solution and alteration products. The rates of these processes are strongly influenced and are coupled through the solution chemistry, which is in turn influenced by the reacting glass and also by reaction with the near-field materials and precipitation of alteration products. Therefore, those processes must be understood sufficiently well to estimate or bound the performance of HLW glass in its disposal environment over geologic time-scales. This article summarizes the current state of understanding of surface reactions, transport properties, and ion exchange along with the near-field materials and alteration products influences on solution chemistry and glass reaction rates. Also summarized are the remaining technical gaps along with recommended approaches to fill those technical gaps.

  8. Rhenium solubility in borosilicate nuclear waste glass: implications for the processing and immobilization of technetium-99.

    PubMed

    McCloy, John S; Riley, Brian J; Goel, Ashutosh; Liezers, Martin; Schweiger, Michael J; Rodriguez, Carmen P; Hrma, Pavel; Kim, Dong-Sang; Lukens, Wayne W; Kruger, Albert A

    2012-11-20

    The immobilization of technetium-99 ((99)Tc) in a suitable host matrix has proven to be a challenging task for researchers in the nuclear waste community around the world. In this context, the present work reports on the solubility and retention of rhenium, a nonradioactive surrogate for (99)Tc, in a sodium borosilicate glass. Glasses containing target Re concentrations from 0 to 10,000 ppm [by mass, added as KReO(4) (Re(7+))] were synthesized in vacuum-sealed quartz ampules to minimize the loss of Re from volatilization during melting at 1000 °C. The rhenium was found as Re(7+) in all of the glasses as observed by X-ray absorption near-edge structure. The solubility of Re in borosilicate glasses was determined to be ~3000 ppm (by mass) using inductively coupled plasma optical emission spectroscopy. At higher rhenium concentrations, additional rhenium was retained in the glasses as crystalline inclusions of alkali perrhenates detected with X-ray diffraction. Since (99)Tc concentrations in a glass waste form are predicted to be <10 ppm (by mass), these Re results implied that the solubility should not be a limiting factor in processing radioactive wastes, assuming Tc as Tc(7+) and similarities between Re(7+) and Tc(7+) behavior in this glass system. PMID:23101883

  9. Low-temperature lithium diffusion in simulated high-level boroaluminosilicate nuclear waste glasses

    SciTech Connect

    Neeway, James J.; Kerisit, Sebastien N.; Gin, Stephane; Wang, Zhaoying; Zhu, Zihua; Ryan, Joseph V.

    2014-12-01

    Ion exchange is recognized as an integral, if underrepresented, mechanism influencing glass corrosion. However, due to the formation of various alteration layers in the presence of water, it is difficult to conclusively deconvolute the mechanisms of ion exchange from other processes occurring simultaneously during corrosion. In this work, an operationally inert non-aqueous solution was used as an alkali source material to isolate ion exchange and study the solid-state diffusion of lithium. Specifically, the experiments involved contacting glass coupons relevant to the immobilization of high-level nuclear waste, SON68 and CJ-6, which contained Li in natural isotope abundance, with a non-aqueous solution of 6LiCl dissolved in dimethyl sulfoxide at 90 °C for various time periods. The depth profiles of major elements in the glass coupons were measured using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Lithium interdiffusion coefficients, DLi, were then calculated based on the measured depth profiles. The results indicate that the penetration of 6Li is rapid in both glasses with the simplified CJ-6 glass (D6Li ? 4.0-8.0 × 10-21 m2/s) exhibiting faster exchange than the more complex SON68 glass (DLi ? 2.0-4.0 × 10-21 m2/s). Additionally, sodium ions present in the glass were observed to participate in ion exchange reactions; however, different diffusion coefficients were necessary to fit the diffusion profiles of the two alkali ions. Implications of the diffusion coefficients obtained in the absence of alteration layers to the long-term performance of nuclear waste glasses in a geological repository system are also discussed.

  10. ANNUAL PROGRESS REPORT. IRON PHOSPHATE GLASSES: AN ALTERNATIVE FOR VITRIFYING CERTAIN NUCLEAR WASTES

    EPA Science Inventory

    A high priority has been given to investigating the vitrification of three specific nuclear wastes in iron phosphate glasses (IPG). These wastes, which were recommended by the Tank Focus Area (TFA) group of Hanford, are poorly suited for vitrification in the currently DOE-approve...

  11. FTIR spectra and properties of iron borophosphate glasses containing simulated nuclear wastes

    NASA Astrophysics Data System (ADS)

    Liao, Qilong; Wang, Fu; Chen, Kuiru; Pan, Sheqi; Zhu, Hanzhen; Lu, Mingwei; Qin, Jianfa

    2015-07-01

    30 wt.% simulated nuclear wastes were successfully immobilized by B2O3-doped iron phosphate base glasses. The structure and thermal stability of the prepared wasteforms were characterized by Fourier transform infrared spectroscopy and differential thermal analysis, respectively. The subtle structural variations attributed to different B2O3 doping modes have been discussed in detail. The results show that the thermal stability and glass forming tendency of the iron borophosphate glass wasteforms are faintly affected by different B2O3 doping modes. The main structural networks of iron borophosphate glass wasteforms are PO43-, P2O74-, [BO4] groups. Furthermore, for the wasteform prepared by using 10B2O3-36Fe2O3-54P2O5 as base glass, the distributions of Fe-O-P bonds, [BO4], PO43- and P2O74- groups are optimal. In general, the dissolution rate (DR) values of the studied iron borophosphate wasteforms are about 10-8 g cm-2 min-1. The obtained conclusions can offer some useful information for the disposal of high-level radioactive wastes using boron contained phosphate glasses.

  12. High-level nuclear waste borosilicate glass: A compendium of characteristics

    SciTech Connect

    Cunnane, J.C.; Bates, J.K.; Ebert, W.L.; Feng, X.; Mazer, J.J.; Wronkiewicz, D.J.; Sproull, J.; Bourcier, W.L.; McGrail, B.P.

    1992-12-01

    With the imminent startup, in the United States, of facilities for vitrification of high-level nuclear waste, a document has been prepared that compiles the scientific basis for understanding the alteration of the waste glass products under the range of service conditions to which they may be exposed during storage, transportation, and eventual geologic disposal. A summary of selected parts of the content of this document is provided. Waste glass alterations in a geologic repository may include corrosion of the glass network due to groundwater and/or water vapor contact. Experimental testing results are described and interpreted in terms of the underlying chemical reactions and physical processes involved. The status of mechanistic modeling, which can be used for long-term predictions, is described and the remaining uncertainties associated with long-term simulations are summarized.

  13. High-level nuclear waste borosilicate glass: A compendium of characteristics

    SciTech Connect

    Cunnane, J.C.; Bates, J.K.; Ebert, W.L.; Feng, X.; Mazer, J.J.; Wronkiewicz, D.J. ); Sproull, J. ); Bourcier, W.L. ); McGrail, B.P. )

    1992-01-01

    With the imminent startup, in the United States, of facilities for vitrification of high-level nuclear waste, a document has been prepared that compiles the scientific basis for understanding the alteration of the waste glass products under the range of service conditions to which they may be exposed during storage, transportation, and eventual geologic disposal. A summary of selected parts of the content of this document is provided. Waste glass alterations in a geologic repository may include corrosion of the glass network due to groundwater and/or water vapor contact. Experimental testing results are described and interpreted in terms of the underlying chemical reactions and physical processes involved. The status of mechanistic modeling, which can be used for long-term predictions, is described and the remaining uncertainties associated with long-term simulations are summarized.

  14. Na, Mg, Ni and Cs distribution and speciation after long-term alteration of a simulated nuclear waste glass

    E-print Network

    waste glass: A micro-XAS/XRF/XRD and wet chemical study Enzo Curti a,d,*, Rainer Da¨hn a , Franc�ois distribution and speciation of Na, Mg, Ni and Cs in a simulated (inactive) nuclear waste glass were studied leaching during 12 years at 90 °C. Na and Mg are major constituents of the glass that can be used

  15. THERMOCHEMICAL MODELS FOR NUCLEAR WASTE GLASS SUBSYSTEMS - MGO-CAO AND MGO-AL2O3

    EPA Science Inventory

    A relatively simple model, the associate species model, is being applied to nuclear waste glass compositions in order to accurately predict behavior and thermodynamic activities in the material. In the model, the glass is treated as a supercooled liquid, with the liquid species ...

  16. Rhenium Solubility in Borosilicate Nuclear Waste Glass: Implications for the Processing and Immobilization of Technetium-99

    SciTech Connect

    McCloy, John S.; Riley, Brian J.; Goel, Ashutosh; Liezers, Martin; Schweiger, Michael J.; Rodriguez, Carmen P.; Hrma, Pavel R.; Kim, Dong-Sang; Lukens, Wayne W.; Kruger, Albert A.

    2012-10-26

    The immobilization of 99Tc in a suitable host matrix has proved to be an arduous task for the researchers in nuclear waste community around the world. At the Hanford site in Washington State, the total amount of 99Tc in low-activity waste (LAW) is ~1300 kg and the current strategy is to immobilize the 99Tc in borosilicate glass with vitrification. In this context, the present article reports on the solubility/retention of rhenium, a nonradioactive surrogate for 99Tc, in a LAW borosilicate glass. Due to the radioactive nature of technetium, rhenium was chosen as a simulant because of the similarity between their ionic radii and other chemical aspects. The glasses containing Re (0 – 10,000 ppm by mass) were synthesized in vacuum-sealed quartz ampoules in order to minimize the loss of Re by volatilization during melting at 1000 °C. The rhenium was found to predominantly exist as Re (VII) in all the glasses as observed by X-ray absorption near-edge structure (XANES). The solubility of Re in borosilicate glasses was determined to be ~3000 ppm (by mass) with inductively coupled plasma-optical emission spectroscopy (ICP-OES). At higher rhenium concentrations, some additional material was retained in the glasses in the form of crystalline inclusions that were detected by X-ray diffraction (XRD) and laser ablation-ICP mass spectrometry (LA-ICP-MS). The implications of these results on the immobilization of 99Tc from radioactive wastes in borosilicate glasses have been discussed.

  17. Pyrochlore based glass-ceramics for the immobilization of actinide-rich nuclear wastes: From concept to reality

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Zhang, Z.; Thorogood, G.; Vance, E. R.

    2013-01-01

    Pyrochlore based glass-ceramics have been developed, from concept to reality, for the immobilization of actinide-rich nuclear wastes. Compared with zirconolite based glass-ceramics, they are less sensitive to the processing redox conditions and can double actinide waste loadings thus decreasing volumes of the consolidated waste forms, and subsequently reducing the interim storage and disposal costs. More importantly, they provide an alternative flexible system to tackle radioactive wastes arising from the advanced nuclear reactors.

  18. Nepheline Crystallization in Nuclear Waste Glasses: Progress toward acceptance of high-alumina formulations

    SciTech Connect

    McCloy, John S.; Schweiger, Michael J.; Rodriguez, Carmen P.; Vienna, John D.

    2011-09-01

    We have critically compiled and analyzed historical data for investigating the quantity of nepheline (NaAlSiO4) precipitation as a function of composition in simulated nuclear waste glasses. To understand composition we used two primary methods: 1) investigating the Al2O3-SiO2-Na2O ternary with filtering for different B2O3 levels and 2) creating a quadrant system consisting of compositions reduced to two metric numbers. These metrics are 1) the nepheline discriminator (ND) which depends only on the SiO2 content by weight normalized to the total weight of the Al2O3-SiO2-Na2O sub-mixture and 2) the optical basicity (OB) which contains contributions from all constituents in the glass. Nepheline precipitation is expected to be suppressed at high SiO2 levels (ND >0.62) or at low basicities (OB <0.55 to 0.57). Changes in sodium aluminosilicate glass OB due to additions of CaO and B2O3 correlate with observed effects on nepheline formation. We propose that additional composition space is available for formulating high-waste-loading, high-Al¬2O3 nuclear waste glasses when Na2O levels are less than ~0.125 (normalized by weight on the Al2O3-SiO2-Na2O sub-mixture). However, this compositional space is considerably extended to higher Na2O levels when adding >5 wt% B2O3. The OB concept can help further refine regions of nepheline-free glass formation.

  19. Nepheline crystallization in boron-rich alumino-silicate glasses as investigated by multi-nuclear NMR, Raman, & Mössbauer spectroscopies

    SciTech Connect

    Mccloy, John S.; Washton, Nancy M.; Gassman, Paul L.; Marcial, Jose; Weaver, Jamie L.; Kukkadapu, Ravi K.

    2015-02-01

    A spectroscopic study was conducted on 6 complex simulant nuclear waste glasses using multi-nuclear NMR, Raman and Mössbauer spectroscopies to explore the role of glass-forming elements Si, Al, B, along with Na and Fe and to understand their connectivity with the goal of understanding melt structure precursors to deleterious feldspathoid nepheline-like crystals formation. NMR showed the appearance of two sites for Al, Si, and Na in the samples which crystallized significant amounts of nepheline, and B speciation changed, typically resulting in more B(IV) after nepheline crystallization. Raman spectroscopy suggested a major part of the glass structure is composed of metaborate chains or rings, thus significant numbers of non-bridging oxygens and a separation of the borate from the alumino-silicate network. Mössbauer combined with Fe redox chemical measurements showed that Fe plays a minor role in these glasses, mostly as Fe3+, but that iron oxide spinel forms with nepheline in all cases. Models of the glass network, speciation of B, and allocation of non-bridging oxygens were computed. The Yun-Dell-Bray model failed to predict the observed high concentration of NBO necessary to explain the metaborate features in the Raman spectra, and it largely over-estimated B(IV) fraction. The model assuming Na-Al-Si moieties and using experimental B(IV) fraction predicted a large amount of NBO consistent with Raman spectra. An alternative notation for appreciating the glass network is suggested and then used to investigate the changes the glass due to crystallization of sodium nepheline and the residual glass network. From a theoretical standpoint, it may be preferred to picture nuclear waste glasses by the Lebedev theory of glass structure where “microcrystallites” of ordered nuclei (or embryos) exist in the matrix of more disordered glass.

  20. Obsidians and tektites: Natural analogues for water diffusion in nuclear waste glasses

    SciTech Connect

    Mazer, J.J.; Bates, J.K.; Bradley, C.R.; Stevenson, C.M.

    1991-11-01

    Projected scenarios for the proposed Yucca Mountain repository include significant periods of time when high relative humidity atmospheres will be present, thus the reaction processes of interest will include those known to occur under these conditions. The ideal natural analog for the proposed Yucca Mountain repository would consist of natural borosilicate glasses exposed to expected repository conditions for thousands of years; however, the prospects for identifying such an analog are remote, but an important caveat for using natural analog studies is to relate the reaction processes in the analog to those in the system of interest, rather than a strict comparison of the glass compositions. In lieu of this, identifying natural glasses that have reacted via reaction processes expected in the repository is the most attractive option. The goal of this study is to quantify molecular water diffusion in the natural analogs obsidian and tektites. Results from this study can be used in assessing the importance of factors affecting molecular water diffusion in nuclear waste glasses, relative to other identified reaction processes. In this way, a better understanding of the long-term reaction mechanism can be developed and incorporated into performance assessment models. 17 refs., 4 figs.

  1. Fibrous-glass aerosols: a literature review. Special report. [On nuclear submarines

    SciTech Connect

    Laverty, B.R.

    1987-10-02

    The submarine atmospheric is a topic of interest, considering that once submerged, the craft relies on its own electrostatic precipitators (ESP's), scrubbers, and filters to create, ideally, an environment with minimal aerosolized toxic materials and other by-products. Historically, atmosphere sampling aboard nuclear submarines has shown contaminants. Other contaminants include: ozone, (major source: by-product of the ESP's); freon, (major source: ship's refrigeration system and air-conditioning plants); hydrogen, (major source: ship's batteries); carbon dioxide, (major source: human respiration); and carbon monoxide, (major source: cigarette smoking). Contaminants tested for but not found were elemental mercury and asbestos. Considering that asbestos is no longer recommended for use, secondary to its carcinogenic and co-carcinogenic qualities, fibrous glass has become a common substitute. One use of fibrous glass aboard the Ohio class submarine is acoustic and thermal insulation around perforated ducting, which runs through many exposed, high traffic spaces, i.e. crew's berthing spaces. Although the raw fibrous glass is protected from the environment it is possible, through natural wear and tear of the housing material, that at some time the insulating material may become exposed and mechanically aerosolized. Obvious questions then are: a) do submarine aerosols contain fiber glass, and b) are there health hazards related to the inhalation of these fibers. This paper reviews the current knowledge as to the health hazard of exposure.

  2. Conversion of Nuclear Waste into Nuclear Waste Glass: Experimental Investigation and Mathematical Modeling

    SciTech Connect

    Hrma, Pavel

    2014-12-18

    The melter feed, slurry, or calcine charged on the top of a pool of molten glass forms a floating layer of reacting material called the cold cap. Between the cold-cap top, which is covered with boiling slurry, and its bottom, where bubbles separate it from molten glass, the temperature changes by up to 1000 K. The processes that occur over this temperature interval within the cold cap include liberation of gases, conduction and consumption of heat, dissolution of quartz particles, formation and dissolution of intermediate crystalline phases, and generation of foam and gas cavities. These processes have been investigated using thermal analyses, optical and electronic microscopies, x-ray diffraction, as well as other techniques. Properties of the reacting feed, such as heat conductivity and density, were measured as functions of temperature. Investigating the structure of quenched cold caps produced in a laboratory-scale melter complemented the crucible studies. The cold cap consists of two main layers. The top layer contains solid particles dissolving in the glass-forming melt and open pores through which gases are escaping. The bottom layer contains bubbly melt or foam where bubbles coalesce into larger cavities that move sideways and release the gas to the atmosphere. The feed-to-glass conversion became sufficiently understood for representing the cold-cap processes via mathematical models. These models, which comprise heat transfer, mass transfer, and reaction kinetics models, have been developed with the final goal to relate feed parameters to the rate of glass melting.

  3. Conversion of Nuclear Waste into Nuclear Waste Glass: Experimental Investigation and Mathematical Modeling

    DOE PAGESBeta

    Hrma, Pavel

    2014-12-18

    The melter feed, slurry, or calcine charged on the top of a pool of molten glass forms a floating layer of reacting material called the cold cap. Between the cold-cap top, which is covered with boiling slurry, and its bottom, where bubbles separate it from molten glass, the temperature changes by up to 1000 K. The processes that occur over this temperature interval within the cold cap include liberation of gases, conduction and consumption of heat, dissolution of quartz particles, formation and dissolution of intermediate crystalline phases, and generation of foam and gas cavities. These processes have been investigated usingmore »thermal analyses, optical and electronic microscopies, x-ray diffraction, as well as other techniques. Properties of the reacting feed, such as heat conductivity and density, were measured as functions of temperature. Investigating the structure of quenched cold caps produced in a laboratory-scale melter complemented the crucible studies. The cold cap consists of two main layers. The top layer contains solid particles dissolving in the glass-forming melt and open pores through which gases are escaping. The bottom layer contains bubbly melt or foam where bubbles coalesce into larger cavities that move sideways and release the gas to the atmosphere. The feed-to-glass conversion became sufficiently understood for representing the cold-cap processes via mathematical models. These models, which comprise heat transfer, mass transfer, and reaction kinetics models, have been developed with the final goal to relate feed parameters to the rate of glass melting.« less

  4. THE STRUCTURAL CHEMISTRY OF MOLYBDENUM IN MODEL HIGH LEVEL NUCLEAR WASTE GLASSES, INVESTIGATED BY MO K-EDGE X-RAY ABSORPTION

    E-print Network

    Sheffield, University of

    THE STRUCTURAL CHEMISTRY OF MOLYBDENUM IN MODEL HIGH LEVEL NUCLEAR WASTE GLASSES, INVESTIGATED of molybdenum in model UK high level nuclear waste glasses was investigated by X-ray Absorption Spectroscopy (XAS). Molybdenum K-edge XAS data were acquired from several inactive simulant high level nuclear waste

  5. Raman Spectra, Structural Units and Durability of Nuclear Waste Glasses With Variations in Composition and Crystallization: Implications for Intermediate Order in the Glass Network

    SciTech Connect

    Raman, Swaminathan Venkat

    2002-11-01

    The Raman spectra of nuclear waste glasses are composed of large variations in half-width and intensity for the commonly observed bridging (Q0) and nonbridging (Q1 to Q4) bands in silicate structures. With increase in waste concentration in a boroaluminosilicate melt, the bands of quenched glasses are distinctly localized with half-width and intensity indicative of increase in atomic order. Since the nuclear waste glasses contain disparate components, and since the bands depart from the typical random network, a systematic study for the origin of these bands as a function of composition and crystallization was undertaken. From a comparative study of Raman spectra of boroaluminosilicate glasses containing Na2O-ZrO2, Na2O-MgO, MgO-Na2O-ZrO2, Na2O-CaO-ZrO2, Na2O-CaO, and Na2O-MgO-CaF2 component sets and orthosilicate crystals of zircon and forsterite, intermediate order is inferred. An edge-sharing polyhedral structural unit is proposed to account for narrow bandwidth and high intensity for Q2 antisymmetric modes, and decreased leaching of sodium with ZrO2 concentration in glass. The intense Q4 band in nuclear waste glass is similar to the intertetrahedral antisymmetric modes in forsterite. The Raman spectra of zircon contains intratetrahedral quartz-like peaks and intertetrahedral non-bridging silicate peaks. The quartz-like peaks nearly vanish in the background of forsterite spectrum. This difference between the Raman spectra of the two orthosilicate crystals presumably results from their biaxial and uniaxial effects on polarizability ellipsoids. The results also reveal formation of 604, 956 and 961 cm-1 defect bands with composition and crystallization.

  6. Relaxation transition in glass-forming polybutadiene as revealed by nuclear resonance X-ray scattering

    NASA Astrophysics Data System (ADS)

    Kanaya, Toshiji; Inoue, Rintaro; Saito, Makina; Seto, Makoto; Yoda, Yoshitaka

    2014-04-01

    We investigated the arrest mechanism of molecular motions in a glass forming polybutadiene near the glass transition using a new nuclear resonance synchrotron X-ray scattering technique to cover a wide time range (10-9 to 10-5 s) and a scattering vector Q range (9.6-40 nm-1), which have never been accessed by other methods. Owing to the wide time and Q ranges it was found for the first time that a transition of the ?-process to the slow ?-process (or the Johari-Goldstein process) was observed in a Q range higher than the first peak in the structure factor S(Q) at the critical temperature Tc in the mode coupling theory. The results suggest the important roles of hopping motions below Tc, which was predicted by the recent extended mode coupling theory and the cooperative motions due to the strong correlation at the first peak in S(Q) in the arrest mechanism.

  7. Model for the conversion of nuclear waste melter feed to glass

    SciTech Connect

    Pokorny, Richard; Hrma, Pavel R.

    2014-02-01

    The rate of batch-to-glass conversion is a primary concern for the vitrification of nuclear waste, as it directly influences the life cycle of the cleanup process. This study describes the development of an advanced model of the cold cap, which augments the previous model by further developments on the structure and the dynamics of the foam layer. The foam layer on the bottom of the cold cap consists of the primary foam, cavities, and the secondary foam, and forms an interface through which the heat is transferred to the cold cap. Other model enhancements include the behavior of intermediate crystalline phases and the dissolution of quartz particles. The model relates the melting rate to feed properties and melter conditions, such as the molten glass temperature, foaminess of the feed, or the heat fraction supplied to the cold cap from the plenum space. The model correctly predicts a 25% increase in melting rate when changing the alumina source in the melter feed from Al(OH)3 to AlO(OH). It is expected that this model will be incorporated in the full glass melter model as its integral component.

  8. DIADDHEM set-up: New IBA facility for studying the helium behavior in nuclear glasses

    NASA Astrophysics Data System (ADS)

    Chamssedine, F.; Sauvage, T.; Peuget, S.

    2010-06-01

    The immobilization of fission products and minor actinides by vitrification is the reference process for industrial management of high-level radioactive wastes generated from spent fuel reprocessing. The glassy matrix is subjected to radiation damage and radiogenic helium generation due to the alpha decays of minor actinides. A specific experimental study has been conducted to better understand the behavior of helium and its diffusion mechanisms in the borosilicate glass. Helium production is simulated by external irradiation with 3He + ions at a concentration (2 × 10 15 He cm -2) equivalent to the one obtained after 1000 years of glass storage. He diffusion coefficients as function of temperature are extracted from the evolution of the depth profiles after annealing. The 3He(d, ?) 1H Nuclear Reaction Analysis (NRA) technique is successfully used for in situ low-temperature measurements of depth profiles. Its high depth resolution allows detecting helium mobility at a temperature as low as 250 K and the presence of a trapped helium fraction. The good agreement of our first values of diffusion coefficients with the literature data highlights the relevance of the implantation technique in the study of helium diffusion mechanisms in borosilicate glasses.

  9. Model for the conversion of nuclear waste melter feed to glass

    NASA Astrophysics Data System (ADS)

    Pokorny, Richard; Hrma, Pavel

    2014-02-01

    The rate of batch-to-glass conversion is a primary concern for the vitrification of nuclear waste, as it directly influences the life cycle of the cleanup process. This study describes the development of an advanced model of the cold cap, which augments the previous model by further developments on the structure and the dynamics of the foam layer. The foam layer on the bottom of the cold cap consists of the primary foam, cavities, and the secondary foam, and forms an interface through which the heat is transferred to the cold cap. Other model enhancements include the behavior of intermediate crystalline phases and the dissolution of quartz particles. The model relates the melting rate to feed properties and melter conditions, such as the molten glass temperature, foaminess of the melt, or the heat fraction supplied to the cold cap from the plenum space. The model correctly predicts a 25% increase in melting rate when changing the alumina source in the melter feed from Al(OH)3 to AlO(OH). It is expected that this model will be incorporated in the full glass melter model as its integral component.

  10. Contribution of atom-probe tomography to a better understanding of glass alteration mechanisms: application to a nuclear glass specimen altered 25 years in a granitic environment

    SciTech Connect

    Gin, Stephane; Ryan, Joseph V.; Schreiber, Daniel K.; Neeway, James J.; Cabie, M.

    2013-06-01

    We report and discuss results of atom probe tomography (APT) and energy-filtered transmission electron microscopy (EFTEM) applied to a borosilicate glass sample of nuclear interest altered for nearly 26 years at 90°C in a confined granitic medium in order to better understand the rate-limiting mechanisms under conditions representative of a deep geological repository for vitrified radioactive waste. The APT technique allows the 3D reconstruction of the elemental distribution at the reactive interphase with sub-nanometer precision. Profiles of the B distribution at pristine glass/hydrated glass interface obtained by different techniques are compared to show the challenge of accurate measurements of diffusion profiles at this buried interface on the nanometer length scale. Our results show that 1) Alkali from the glass and hydrogen from the solution exhibit anti-correlated 15 ± 3 nm wide gradients located between the pristine glass and the hydrated glass layer, 2) boron exhibits an unexpectedly sharp profile located just at the outside of the alkali/H interdiffusion layer; this sharp profile is more consistent with a dissolution front than a diffusion-controlled release of boron. The resulting apparent diffusion coefficients derived from the Li and H profiles are DLi = 1.5 × 10-22 m2.s-1 and DH = 6.8 × 10-23 m2.s-1. These values are around two orders of magnitude lower than those observed at the very beginning of the alteration process, which suggests that interdiffusion is slowed at high reaction progress by local conditions that could be related to the porous structure of the interphase. As a result, the accessibility of water to the pristine glass could be the rate-limiting step in these conditions. More generally, these findings strongly support the importance of interdiffusion coupled with hydrolysis reactions of the silicate network on the long-term dissolution rate, contrary to what has been suggested by recent interfacial dissolution-precipitation models for silicate minerals.

  11. Radiation effects in moist-air systems and the influence of radiolytic product formation on nuclear waste glass corrosion

    SciTech Connect

    Wronkiewicz, D.J.; Bates, J.K.; Buck, E.C.; Hoh, J.C.; Emery, J.W.; Wang, L.M.

    1997-07-01

    Ionizing radiation may affect the performance of glass in an unsaturated repository site by interacting with air, water vapor, or liquid water to produce a variety of radiolytic products. Tests were conducted to examine the effects of radiolysis under high gas/liquid ratios. Results indicate that nitrate is the predominant radiolytic product produced following both gamma and alpha radiation exposure, with lesser amounts of nitrite and carboxylic acids. The formation of nitrogen acids during exposure to long-lived, alpha-particle-emitting transuranic elements indicates that these acids may play a role in influencing nuclear waste form reactions in a long-term unsaturated disposal scenario. Experiments were also conducted with samples that simulate the composition of Savannah River Plant nuclear waste glasses. Radiolytic product formation in batch tests (340 m{sup {minus}1}, 90 C) resulted in a small increase in the release rates of many glass components, such as alkali and alkaline earth elements, although silicon and uranium release rates were slightly reduced indicating an overall beneficial effect of radiation on waste form stability. The radiolytic acids increased the rate of ion exchange between the glass and the thin film of condensate, resulting in accelerated corrosion rates for the glass. The paragenetic sequence of alteration phases formed on both the irradiated and nonirradiated glass samples reacted in the vapor hydration tests matches closely with those developed during volcanic glass alteration in naturally occurring saline-alkaline lake systems. This correspondence suggests that the high temperatures used in these tests have not changed the underlying glass reaction mechanism relate to that which controls glass reactions under ambient surficial conditions.

  12. MOLYBDENUM IN GLASSES CONTAINING VITRIFIED NUCLEAR R.J. Hand, R.J. Short, S. Morgan, N.C. Hyatt, G. Mbus and W.E. Lee

    E-print Network

    Sheffield, University of

    MOLYBDENUM IN GLASSES CONTAINING VITRIFIED NUCLEAR WASTE R.J. Hand, R.J. Short, S. Morgan, N.hand@sheffield.ac.uk Immobilisation of molybdenum in high level nuclear waste glasses melted under oxidising, neutral and reducing). Molybdenum is present in all cases in the hexavalent oxidation state as the tetrahedral MoO4 2- molybdate

  13. Heat Transfer in Waste Glass Melts - Measurement and Implications for Nuclear Waste Vitrification

    NASA Astrophysics Data System (ADS)

    Wang, Chuan

    Thermal properties of waste glass melts, such as high temperature density and thermal conductivity, are relevant to heat transfer processes in nuclear waste vitrification. Experimental measurement techniques were developed and applied to four nuclear waste glasses representative of those currently projected for treatment of Hanford HLW and LAW streams to study heat flow mechanisms in nuclear waste vitrification. Density measurement results by Archimedes' method indicated that densities of the melts investigated varied considerably with composition and temperature. Thermal diffusivities of waste melts were determined at nominal melter operating temperatures using a temperature-wave technique. Thermal conductivities were obtained by combining diffusivity data with the experimentally-acquired densities of the melts and their known heat capacities. The experimental results display quite large positive dependences of conductivities on temperature for some samples and much weaker positive temperature dependences for others. More importantly, there is observed a big change in the slopes of the conductivities versus temperature as temperature is increased for two of the melts, but not for the other two. This behavior was interpreted in terms of the changing contributions of radiation and conduction with temperature and composition dependence of the absorption coefficient. Based on the obtained thermal conductivities, a simple model for a waste glass melter was set up, which was used to analyze the relative contributions of conduction and radiation individually and collectively to the overall heat flow and to investigate factors and conditions that influence the radiation contribution to heat flow. The modeling results showed that unlike the case at lower temperatures, the radiant energy flow through waste melts could be predominant compared with conduction at temperature of about 900 °C or higher. However, heat flow due to radiation was roughly equal to that from conduction as temperatures below about 700 °C. Moreover, the effect was reduced for higher absorption coefficient samples. Modeling further demonstrated that geometry exerts a significant influence on the radiation contribution to heat transfer. Room temperature radiation absorption coefficients of the same samples were determined using FTIR, which were compared with those estimated by modeling.

  14. Dynamics of asymmetric binary glass formers. I. A dielectric and nuclear magnetic resonance spectroscopy study

    SciTech Connect

    Kahlau, R.; Bock, D.; Schmidtke, B.; Rössler, E. A.

    2014-01-28

    Dielectric spectroscopy as well as {sup 2}H and {sup 31}P nuclear magnetic resonance spectroscopy (NMR) are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene (PS/PS-d{sub 3}) in the full concentration (c{sub TPP}) range. In addition, depolarized light scattering and differential scanning calorimetry experiments are performed. Two glass transition temperatures are found: T{sub g1}(c{sub TPP}) reflects PS dynamics and shows a monotonic plasticizer effect, while the lower T{sub g2}(c{sub TPP}) exhibits a maximum and is attributed to (faster) TPP dynamics, occurring in a slowly moving or immobilized PS matrix. Dielectric spectroscopy probing solely TPP identifies two different time scales, which are attributed to two sub-ensembles. One of them, again, shows fast TPP dynamics (?{sub 2}-process), the other (?{sub 1}-process) displays time constants identical with those of the slow PS matrix. Upon heating the ?{sub 1}-fraction of TPP decreases until above some temperature T{sub c} only a single ?{sub 2}-population exists. Inversely, below T{sub c} a fraction of the TPP molecules is trapped by the PS matrix. At low c{sub TPP} the ?{sub 2}-relaxation does not follow frequency-temperature superposition (FTS), instead it is governed by a temperature independent distribution of activation energies leading to correlation times which follow Arrhenius laws, i.e., the ?{sub 2}-relaxation resembles a secondary process. Yet, {sup 31}P NMR demonstrates that it involves isotropic reorientations of TPP molecules within a slowly moving or rigid matrix of PS. At high c{sub TPP} the super-Arrhenius temperature dependence of ?{sub 2}(T), as well as FTS are recovered, known as typical of the glass transition in neat systems.

  15. Dynamics of asymmetric binary glass formers. II. Results from nuclear magnetic resonance spectroscopy

    SciTech Connect

    Bock, D.; Kahlau, R.; Pötzschner, B.; Körber, T.; Wagner, E.; Rössler, E. A.

    2014-03-07

    Various {sup 2}H and {sup 31}P nuclear magnetic resonance (NMR) spectroscopy techniques are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene-d{sub 3} (PS) over the full concentration range. The results are quantitatively compared to those of a dielectric spectroscopy (DS) study on the same system previously published [R. Kahlau, D. Bock, B. Schmidtke, and E. A. Rössler, J. Chem. Phys. 140, 044509 (2014)]. While the PS dynamics does not significantly change in the mixtures compared to that of neat PS, two fractions of TPP molecules are identified, one joining the glass transition of PS in the mixture (?{sub 1}-process), the second reorienting isotropically (?{sub 2}-process) even in the rigid matrix of PS, although at low concentration resembling a secondary process regarding its manifestation in the DS spectra. Pronounced dynamical heterogeneities are found for the TPP ?{sub 2}-process, showing up in extremely stretched, quasi-logarithmic stimulated echo decays. While the time window of NMR is insufficient for recording the full correlation functions, DS results, covering a larger dynamical range, provide a satisfactory interpolation of the NMR data. Two-dimensional {sup 31}P NMR spectra prove exchange within the broadly distributed ?{sub 2}-process. As demonstrated by {sup 2}H NMR, the PS matrix reflects the faster ?{sub 2}-process of TPP by performing a spatially highly hindered motion on the same timescale.

  16. Relaxation transition in glass-forming polybutadiene as revealed by nuclear resonance X-ray scattering.

    PubMed

    Kanaya, Toshiji; Inoue, Rintaro; Saito, Makina; Seto, Makoto; Yoda, Yoshitaka

    2014-04-14

    We investigated the arrest mechanism of molecular motions in a glass forming polybutadiene near the glass transition using a new nuclear resonance synchrotron X-ray scattering technique to cover a wide time range (10(-9) to 10(-5) s) and a scattering vector Q range (9.6-40 nm(-1)), which have never been accessed by other methods. Owing to the wide time and Q ranges it was found for the first time that a transition of the ?-process to the slow ?-process (or the Johari-Goldstein process) was observed in a Q range higher than the first peak in the structure factor S(Q) at the critical temperature T(c) in the mode coupling theory. The results suggest the important roles of hopping motions below T(c), which was predicted by the recent extended mode coupling theory and the cooperative motions due to the strong correlation at the first peak in S(Q) in the arrest mechanism. PMID:24735317

  17. Comprehensive data base of high-level nuclear waste glasses: September 1987 status report: Volume 2, Additional appendices

    SciTech Connect

    Kindle, C.H.; Kreiter, M.R.

    1987-12-01

    The Materials Characterization Center (MCC) is assembling a comprehensive data base (CDB) of experimental data collected for high-level nuclear waste package components. The status of the CDB is summarized in Volume I of this report. Volume II contains appendices that present data from the data base and an evaluation of glass durability models applied to the data base.

  18. MASBAL: A computer program for predicting the composition of nuclear waste glass produced by a slurry-fed ceramic melter

    SciTech Connect

    Reimus, P.W.

    1987-07-01

    This report is a user's manual for the MASBAL computer program. MASBAL's objectives are to predict the composition of nuclear waste glass produced by a slurry-fed ceramic melter based on a knowledge of process conditions; to generate simulated data that can be used to estimate the uncertainty in the predicted glass composition as a function of process uncertainties; and to generate simulated data that can be used to provide a measure of the inherent variability in the glass composition as a function of the inherent variability in the feed composition. These three capabilities are important to nuclear waste glass producers because there are constraints on the range of compositions that can be processed in a ceramic melter and on the range of compositions that will be acceptable for disposal in a geologic repository. MASBAL was developed specifically to simulate the operation of the West Valley Component Test system, a commercial-scale ceramic melter system that will process high-level nuclear wastes currently stored in underground tanks at the site of the Western New York Nuclear Services Center (near West Valley, New York). The program is flexible enough, however, to simulate any slurry-fed ceramic melter system. 4 refs., 16 figs., 5 tabs.

  19. Measurement of the nuclear electromagnetic cascade development in glass at energies above 200 GeV

    NASA Technical Reports Server (NTRS)

    Gillespie, C. R.; Huggett, R. W.; Humphreys, D. R.; Jones, W. V.; Levit, L. B.

    1971-01-01

    The longitudinal development of nuclear-electromagnetic cascades with energies greater than 200 GeV was measured in a low-Z (glass) absorber. This was done in the course of operating an ionization spectrometer at mountain altitude in an experiment to study the properties of gamma rays emitted from individual interactions at energies around 10,000 GeV. The ionization produced by a cascade is sampled by 20 sheets of plastic scintillator spaced uniformly in depth every 2.2 radiation lengths. Adjacent pairs of scintillators are viewed by photomultipliers which measure the mean ionization produced by an individual cascade in 10 layers each 1.1 interaction length (4.4 radiation lengths) thick. The longitudinal development of the cascades was measured for about 250 cascades having energies ranging from 200 GeV to 2500 GeV. The observations are compared with the predictions of calculations made for this specific spectrometer using a three-dimensional Monte Carlo model of the nuclear-electromagnetic cascade.

  20. Examining the role of canister cooling conditions on the formation of nepheline from nuclear waste glasses

    SciTech Connect

    Christian, J. H.

    2015-09-01

    Nepheline (NaAlSiO?) crystals can form during slow cooling of high-level waste (HLW) glass after it has been poured into a waste canister. Formation of these crystals can adversely affect the chemical durability of the glass. The tendency for nepheline crystallization to form in a HLW glass increases with increasing concentrations of Al?O? and Na?O.

  1. A review on immobilization of phosphate containing high level nuclear wastes within glass matrix--present status and future challenges.

    PubMed

    Sengupta, Pranesh

    2012-10-15

    Immobilization of phosphate containing high level nuclear wastes within commonly used silicate glasses is difficult due to restricted solubility of P(2)O(5) within such melts and its tendency to promote crystallization. The situation becomes more adverse when sulfate, chromate, etc. are also present within the waste. To solve this problem waste developers have carried out significant laboratory scale research works in various phosphate based glass systems and successfully identified few formulations which apparently look very promising as they are chemically durable, thermally stable and can be processed at moderate temperatures. However, in the absence of required plant scale manufacturing experiences it is not possible to replace existing silicate based vitrification processes by the phosphate based ones. A review on phosphate glass based wasteforms is presented here. PMID:22902141

  2. Isothermal crystallization kinetics in simulated high-level nuclear waste glass

    SciTech Connect

    Vienna, J.D.; Hrma, P.; Smith, D.E.

    1997-12-31

    Crystallization kinetics of a simulated high-level waste (HLW) glass were measured and modelled. Kinetics of acmite growth in the standard HW39-4 glass were measured using the isothermal method. A time-temperature-transformation (TTT) diagram was generated from these data. Classical glass-crystal transformation kinetic models were empirically applied to the crystallization data. These models adequately describe the kinetics of crystallization in complex HLW glasses (i.e., RSquared = 0.908). An approach to measurement, fitting, and use of TTT diagrams for prediction of crystallinity in a HLW glass canister is proposed.

  3. INCORPORATION OF MONO SODIUM TITANATE AND CRYSTALLINE SILICOTITANATE FEEDS IN HIGH LEVEL NUCLEAR WASTE GLASS

    SciTech Connect

    Fox, K.; Johnson, F.; Edwards, T.

    2010-11-23

    Four series of glass compositions were selected, fabricated, and characterized as part of a study to determine the impacts of the addition of Crystalline Silicotitanate (CST) and Monosodium Titanate (MST) from the Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) glass waste form and the applicability of the DWPF process control models. All of the glasses studied were considerably more durable than the benchmark Environmental Assessment (EA) glass. The measured Product Consistency Test (PCT) responses were compared with the predicted values from the current DWPF durability model. One of the KT01-series and two of the KT03-series glasses had measured PCT responses that were outside the lower bound of the durability model. All of the KT04 glasses had durabilities that were predictable regardless of heat treatment or compositional view. In general, the measured viscosity values of the KT01, KT03, and KT04-series glasses are well predicted by the current DWPF viscosity model. The results of liquidus temperature (T{sub L}) measurements for the KT01-series glasses were mixed with regard to the predictability of the T{sub L} for each glass. All of the measured T{sub L} values were higher than the model predicted values, although most fell within the 95% confidence intervals. Overall, the results of this study show a reasonable ability to incorporate the anticipated SCIX streams into DWPF-type glass compositions with TiO{sub 2} concentrations of 4-5 wt % in glass.

  4. Molybdenum in Nuclear Waste Glasses -Incorporation and Redox state R.J. Short, R.J. Hand, N.C. Hyatt,

    E-print Network

    Sheffield, University of

    Molybdenum in Nuclear Waste Glasses - Incorporation and Redox state R.J. Short, R.J. Hand, N or suppress crystallisation in simplified model waste glasses that contain molybdenum. Experiments molybdenum is `yellow phase'. Yellow phase accelerates corrosion of the inconel melters in the liquid state

  5. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    SciTech Connect

    KRUGER AA; HRMA PR

    2009-10-08

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  6. IMPACT OF URANIUM AND THORIUM ON HIGH TIO2 CONCENTRATION NUCLEAR WASTE GLASSES

    SciTech Connect

    Fox, K.; Edwards, T.

    2012-01-11

    This study focused on the potential impacts of the addition of Crystalline Silicotitanate (CST) and Monosodium Titanate (MST) from the Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) glass waste form and the applicability of the DWPF process control models. MST from the Salt Waste Processing Facility (SWPF) is also considered in the study. The KT08-series of glasses was designed to evaluate any impacts of the inclusion of uranium and thorium in glasses containing the SCIX components. All but one of the study glasses were found to be amorphous by X-ray diffraction (XRD). One of the slowly cooled glasses contained a small amount of trevorite, which is typically found in DWPF-type glasses and had no practical impact on the durability of the glass. The measured Product Consistency Test (PCT) responses for the study glasses and the viscosities of the glasses were well predicted by the current DWPF models. No unexpected issues were encountered when uranium and thorium were added to the glasses with SCIX components.

  7. Resarch investigation on dense scintillation glass for use in total absorption nuclear cascade detectors

    NASA Technical Reports Server (NTRS)

    Hensler, J. R.

    1973-01-01

    Three approaches to the development of a high density scintillation glass were investigated: They include the increase of density of glass systems containing cerium - the only systems which were known to show scintillation, the testing of a novel silicate glass system containing significant concentrations of silver produced by ion exchange and never tested previously, and the hot pressing of a diphasic compact of low density scintillation glass with high density passive glass. In first two cases, while ultraviolet excited fluorescence was maintained in the glasses showing high density, scintillation response to high energy particles was not retained in the case of the cerium containing glasses or developed in the case of the silver containing glasses. In the case of the compacts, the extremely long path length caused by the multiple internal reflections which occur in such a body resulted in attenuation even with glasses of high specific transmission. It is not clear why the scintillation efficiency is not maintained in the higher density cerium containing glasses.

  8. INTRINSIC DOSIMETRY OF GLASS CONTAINERS USED TO TRANSPORT NUCLEAR MATERIALS: Potential Implications to the Field of Nuclear Forensics

    SciTech Connect

    Schwantes, Jon M.; Miller, Steven D.; Piper, Roman K.; Murphy, Mark K.; Amonette, James E.; Bonde, Steven E.; Duckworth, Douglas C.

    2008-09-15

    Thermoluminescence (TL) and Electron Paramagnetic Resonance (EPR) dosimetry were used to measure dose effects in borosilicate glass with time, from 10 minutes to ~60 days following exposure to a dose of up to 10,000 Rad. TL and EPR results were consistent and performed similarly, with both techniques capable of achieving an estimated limit of detection of between 50-100 Rad. Three peaks were identified in the TL glow curve at roughly 110oC, 205oC, and 225oC. The intensity of the 205oC peak was the dominant peak over the time period of this study. The stability of all of the peaks with time since irradiation increased with their corresponding temperature and little or no variation was observed in the glow curve response to a specified total dose attained at different dose rates. The intensity of the 205oC peak decreased logarithmically with time regardless of total dose. Based upon a conservative limit of detection of 330 Rad, a 10,000 Rad dose would still be detected 2.7E3 years after exposure. This paper introduces the concept of intrinsic dosimetry, the consideration of a measured dose received to container walls in concert with the physical characteristics of the radioactive material contained inside those walls, as a method for gathering rather unique pathway information about the history of that sample. Three hypothetical scenarios are presented to introduce this method and to illustrate how intrinsic dosimetry might benefit the fields of nuclear forensics and waste management.

  9. First principles process-product models for vitrification of nuclear waste: Relationship of glass composition to glass viscosity, resistivity, liquidus temperature, and durability

    SciTech Connect

    Jantzen, C.M.

    1991-12-31

    Borosilicate glasses will be used in the USA and in Europe to immobilize radioactive high level liquid wastes (HLLW) for ultimate geologic disposal. Process and product quality models based on glass composition simplify the fabrication of the borosilicate glass while ensuring glass processability and quality. The process model for glass viscosity is based on a relationship between the glass composition and its structural polymerization. The relationship between glass viscosity and electrical resistivity is also shown to relate to glass polymerization. The process model for glass liquidus temperature calculates the solubility of the liquidus phases based on the free energies of formation of the precipitating species. The durability product quality model is based on the calculation of the thermodynamic hydration free energy from the glass composition.

  10. First principles process-product models for vitrification of nuclear waste: Relationship of glass composition to glass viscosity, resistivity, liquidus temperature, and durability

    SciTech Connect

    Jantzen, C.M.

    1991-01-01

    Borosilicate glasses will be used in the USA and in Europe to immobilize radioactive high level liquid wastes (HLLW) for ultimate geologic disposal. Process and product quality models based on glass composition simplify the fabrication of the borosilicate glass while ensuring glass processability and quality. The process model for glass viscosity is based on a relationship between the glass composition and its structural polymerization. The relationship between glass viscosity and electrical resistivity is also shown to relate to glass polymerization. The process model for glass liquidus temperature calculates the solubility of the liquidus phases based on the free energies of formation of the precipitating species. The durability product quality model is based on the calculation of the thermodynamic hydration free energy from the glass composition.

  11. Pressure-Induced Glass Formation Studied by Raman Spectroscopy and Nuclear Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Halvorson, Kristofer E.

    The study of vitreous solids, or glasses, is an extremely interesting field in chemistry and physics. It is currently undergoing a renaissance, in which a number of very good workers are directing their efforts toward understanding the physical properties and the formation mechanism of glasses. The predominant external variable in the study of vitrification has been temperature. This dissertation is a study of the role that pressure, a less commonly varied external parameter, plays in the mechanisms of glass formation. With the exception of the introduction, each chapter is a paper either already in print or in manuscript form for publication. This dissertation has two main sections: First, the Raman spectroscopic study of the pressure dependence of the vibrational modes of the metastable form of silica known as alpha-cristobalite. And second, the effects of pressure on the magnetic properties of various hydrogen bonded organic liquids studied via the new ultra-high pressure technique of nuclear magnetic resonance (NMR) using a diamond anvil cell (DAC). In Chapter Two a low pressure phase modification is reported. This modification is assumed to be via a second order phase transition, since it is non-quenchable and has a transition hysteresis of about 3 kbar (P _{rm transition} = 4 kbar). The pressure dependence of Raman active vibrational modes for cristobalite, and the new modification up to 1.3 GPa, are discussed. Chapter Three reports the pressure dependence of the vibration modes of cristobalite, going through several transitions and ending with amorphization. A correlation of the Si-O-Si band behavior among the various polymorphs of silica is also investigated and analyzed. In Chapter Four ultra-high pressure, moderate resolution NMR using a DAC is demonstrated. The pressure dependence of the hydroxyl bands in various organic liquids is described. Chapter Five demonstrates that NMR relaxation data using a DAC is possible. The moderate resolution demonstrated in Chapter Four makes possible for the first time the elucidation of relaxation times for electronically different parts of a molecule at ultra-high pressures. The effects of pressure on the relaxation time of the hydroxyl and aliphytic proton bands in glycerol are also investigated. Chapter Six focuses on the pressure dependence of the hydroxyl proton band in methanol up to 5.8 GPa, the highest pressure NMR data obtained to date. Possible mechanisms for the down-field shift of the hydroxyl proton band resonances are discussed. Finally, Chapter Seven reports the first spin-spin coupling observations at ultra-high pressures using the DAC. The study reveals that carbon 13 enriched methanol has a carbon-proton coupling constant of about 142 Hz. This coupling constant appears pressure independent up to 12 kbar. Finally, the first ever two-dimensional NMR at high pressure using the DAC is demonstrated.

  12. Effect of Callovo-Oxfordian clay rock on the dissolution rate of the SON68 simulated nuclear waste glass

    NASA Astrophysics Data System (ADS)

    Neeway, James J.; Abdelouas, Abdesselam; Ribet, Solange; El Mendili, Yassine; Schumacher, Stéphan; Grambow, Bernd

    2015-04-01

    Long-term storage of high-level nuclear waste glass in France is expected to occur in an engineered barrier system (EBS) located in a subsurface Callovo-Oxfordian (COx) clay rock formation in the Paris Basin in northeastern France. Understanding the behavior of glass dissolution in the complex system is critical to be able to reliably model the performance of the glass in this complex environment. To simulate this multi-barrier repository scenario in the laboratory, several tests have been performed to measure glass dissolution rates of the simulated high-level nuclear waste glass, SON68, in the presence of COx claystone at 90 °C. Experiments utilized a High-Performance Liquid Chromatography (HPLC) pump to pass simulated Bure site COx pore water through a reaction cell containing SON68 placed between two COx claystone cores for durations up to 200 days. Silicon concentrations at the outlet were similar in all experiments, even the blank experiment with only the COx claystone (?4 mg/L at 25 °C and ?15 mg/L at 90 °C). The steady-state pH of the effluent, measured at room temperature, was roughly 7.1 for the blank and 7.3-7.6 for the glass-containing experiments demonstrating the pH buffering capacity of the COx claystone. Dissolution rates for SON68 in the presence of the claystone were elevated compared to those obtained from flow-through experiments conducted with SON68 without claystone in silica-saturated solutions at the same temperature and similar pH values. Additionally, through surface examination of the monoliths, the side of the monolith in direct contact with the claystone was seen to have a corrosion thickness 2.5× greater than the side in contact with the bulk glass powder. Results from one experiment containing 32Si-doped SON68 also suggest that the movement of Si through the claystone is controlled by a chemically coupled transport with a Si retention factor, Kd, of 900 mL/g.

  13. The reaction of synthetic nuclear waste glass in steam and hydrothermal solution

    SciTech Connect

    Ebert, W.L.; Bates, J.K.

    1989-12-31

    Glass monoliths of the WVCM 44, WVCM 50, SRL 165, and SRL 202 compositions were reacted in steam and in hydrothermal liquid at 200{degree}C. The glass reaction resulted in the formation of leached surface layers in both environments. The reaction in steam proceeds at a very low rate until precipitates form, after which the glass reaction proceeds at a greater rate. Precipitates were formed on all glass types reacted in steam. The assemblage of phases formed was unique to each glass type, but several precipitates were common to all glasses, including analcime, gyrolite, and weeksite. Reaction in steam occurs in a thin layer of condensed water which becomes saturated with respect to the observed phases after only a few days of reaction. The reaction in steam is accelerated relative to reaction in hydrothermal liquid in the sense that secondary phases from after a shorter reaction time, that is, after less glass has reacted, because of the smaller effective leachant volume present in the steam environment. A knowledge of the secondary phases which form and their influence on the glass reaction rate is crucial to the modeling effort of the repository program. 9 refs., 3 figs., 2 tabs.

  14. Towards optimization of nuclear waste glass: Constraints, property models, and waste loading

    SciTech Connect

    Hrma, P.

    1994-04-01

    Vitrification of both low- and high-level wastes from 177 tanks at Hanford poses a great challenge to glass makers, whose task is to formulate a system of glasses that are acceptable to the federal repository for disposal. The enormous quantity of the waste requires a glass product of the lowest possible volume. The incomplete knowledge of waste composition, its variability, and lack of an appropriate vitrification technology further complicates this difficult task. A simple relationship between the waste loading and the waste glass volume is presented and applied to the predominantly refractory (usually high-activity) and predominantly alkaline (usually low-activity) waste types. Three factors that limit waste loading are discussed, namely product acceptability, melter processing, and model validity. Glass formulation and optimization problems are identified and a broader approach to uncertainties is suggested.

  15. Use of depleted uranium silicate glass to minimize release of radionuclides from spent nuclear fuel waste packages

    SciTech Connect

    Forsberg, C.W.

    1996-01-20

    A Depleted Uranium Silicate Container Backfill System (DUSCOBS) is proposed that would use small, isotopically-depleted uranium silicate glass beads as a backfill material inside repository waste packages containing spent nuclear fuel (SNF). The uranium silicate glass beads would fill the void space inside the package including the coolant channels inside SNF assemblies. Based on preliminary analysis, the following benefits have been identified. DUSCOBS improves repository waste package performance by three mechanisms. First, it reduces the radionuclide releases from SNF when water enters the waste package by creating a local uranium silicate saturated groundwater environment that suppresses (a) the dissolution and/or transformation of uranium dioxide fuel pellets and, hence, (b) the release of radionuclides incorporated into the SNF pellets. Second, the potential for long-term nuclear criticality is reduced by isotopic exchange of enriched uranium in SNF with the depleted uranium (DU) in the glass. Third, the backfill reduces radiation interactions between SNF and the local environment (package and local geology) and thus reduces generation of hydrogen, acids, and other chemicals that degrade the waste package system. Finally, DUSCOBS provides a potential method to dispose of significant quantities of excess DU from uranium enrichment plants at potential economic savings. DUSCOBS is a new concept. Consequently, the concept has not been optimized or demonstrated in laboratory experiments.

  16. A review of literature pertaining to the leaching and sorption of radionuclides associated with nuclear explosive melt glasses

    SciTech Connect

    Smith, D.K.

    1993-05-01

    For the purposes of groundwater characterization, environmental remediation and health risk assessment, the mechanism and rate by which radionuclides bound within nuclear device melt glass are manifest in Nevada Test Site groundwaters must be known. Exchange between radionuclides and groundwater is dominated by the kinetics of leaching and the resultant sorption of derivative nuclides by minerals along the flow-path. In this context, a survey of the report literature has been conducted to review work related to these subjects. This report provides a representative, although not exhaustive, summary of the literature; because of the specialized nature of nuclear melt glass, emphasis was given to the report literature available from Lawrence Livermore and Los Alamos National Laboratories, the Department of Energy and its predecessor agencies and pertinent contractors. Where data is corroborated in journal literature, those references are also included. Before the risk to ground waters is estimated with any accuracy, recommendations for continued future work integrate systematic characterization of melt glass with leaching studies of these heterogeneous matrices.

  17. The liquidus temperature of nuclear waste glasses: an international Round-Robin Study

    SciTech Connect

    Riley, Brian J.; Hrma, Pavel R.; Vienna, John D.; Schweiger, Michael J.; Rodriguez, Carmen P.; Crum, Jarrod V.; Lang, Jesse B.; Marra, James C.; Johnson, Fabienne; Peeler, David K.; Leonelli, Cristina; Ferrari, Anna M.; Lancellotti, Isabella; Dussossoy, Jean-Lue A.; Hand, Russell J.; Schofield, James M.; Connelly, Andrew J.; Short, Rick; Harrison, Mike T.

    2012-12-01

    Ten institutions from five countries participated in a Round Robin study to contribute to the Precision and Bias section of an American Society for Testing and Materials standard procedure that Pacific Northwest National Laboratory (PNNL) is developing for measuring the liquidus temperature (TL) of radioactive and simulated waste glasses. In this study, three separate TL measurement methods were a gradient temperature (GT) method, a uniform temperature (UT) method, and a crystal fraction extrapolation (CF) method. Three different glasses were measured with a combination of these three methods. The TL values reported by different institutions are generally consistent and vary within a narrow range. The precision of a TL measurement was evaluated as ±10°C regardless of the method used for making the measurement. The Round Robin glasses were all previously studied at PNNL and included ARG-1 (Glass A), Zr-9 (Glass B), and AmCm2-19 (Glass C), with measured TL values spanning the temperature range ~960-1240°C. The three methods discussed here in more detail are the GT, UT, and CF methods. A best-case precision for TL has been obtained from the data, even though the data were not acquired for all three glasses using all three methods from each participating organization.

  18. Helium diffusion coefficient measurements in R7T7 nuclear glass by 3He(d,?) 1H nuclear reaction analysis

    NASA Astrophysics Data System (ADS)

    Chamssedine, F.; Sauvage, T.; Peuget, S.; Fares, T.; Martin, G.

    2010-05-01

    The immobilization of fission products and minor actinides by vitrification is the reference process for industrial management of high-level radioactive wastes generated by spent fuel reprocessing. Radiation damage and radiogenic helium accumulation must be specifically studied to evaluate the effects of minor actinide alpha decay on the glass long-term behavior under repository conditions. A specific experimental study was conducted for a comprehensive evaluation of the behavior of helium and its diffusion mechanisms in borosilicate nuclear waste glass. Helium production was simulated by external implantation with 3He ions at a concentration (?1 at.%) 30 times higher than obtained after 10,000 years of storage. Helium diffusion coefficients as a function of temperature were extracted from the depth profiles after annealing. The 3He(d,?) 1H nuclear reaction analysis (NRA) technique was successfully adopted for low-temperature in situ measurements of depth profiles. Its high depth resolution revealed helium mobility at temperatures as low as 253 K and the presence of a trapped helium fraction. The diffusion coefficients of un-trapped helium atoms follow an Arrhenius law between 253 K and 323 K. An activation energy of 0.55 ± 0.03 eV was determined, which is consistent with a process controlled by diffusion in the glass free volume.

  19. An International Initiative on Long-Term Behavior of High-Level Nuclear Waste Glass

    SciTech Connect

    Gin, Stephane; Abdelouas, Abdesselam; Criscenti, Louise J; Ebert, William L; Ferrand, K; Geisler, T; Harrison, Michael T; Inagaki, Y; Mitsui, S; Mueller, K T; Marra, James C; Pantano, Carlo G; Pierce, Eric M; Ryan, Joseph V; Schofield, J M; Steefel, Carl I; Vienna, John D.

    2013-01-01

    Nations using borosilicate glass as an immobilization material for radioactive waste have reinforced the importance of scientific collaboration to obtain a consensus on the mechanisms controlling the longterm dissolution rate of glass. This goal is deemed to be crucial for the development of reliable performance assessment models for geological disposal. The collaborating laboratories all conduct fundamental and/or applied research using modern materials science techniques. This paper briefly reviews the radioactive waste vitrification programs of the six participant nations and summarizes the current state of glass corrosion science, emphasizing the common scientific needs and justifications for on-going initiatives.

  20. Annual progress report to Battelle Pacific Northwest National Laboratories on prediction of phase separation of simulated nuclear waste glasses

    SciTech Connect

    Sung, Y.M.; Tomozawa, M.

    1996-02-01

    The objective of this research is to predict the immiscibility boundaries of multi-component borosilicate glasses, on which many nuclear waste glass compositions are based. The method used is similar to the prediction method of immiscibility boundaries of multi-component silicate glass systems successfully made earlier and is based upon the superposition of immiscibility boundaries of simple systems using an appropriate parameter. This method is possible because many immiscibility boundaries have similar shapes and can be scaled by a parameter. In the alkali and alkaline earth binary silicate systems, for example, the critical temperature and compositions were scaled using the Debye-Hueckel theory. In the present study on borosilicate systems, first, immiscibility boundaries of various binary alkali and alkaline borate glass systems (e.g. BaO-B{sub 2}O{sub 3}) were examined and their critical temperatures were evaluated in terms of Debye-Hueckel theory. The mixing effects of two alkali and alkaline-earth borate systems on the critical temperature were also explored. Next immiscibility boundaries of ternary borosilicate glasses (e.g. Na{sub 2}O-SiO{sub 2}-B{sub 2}O{sub 3}, K{sub 2}O-SiO{sub 2}-B{sub 2}O{sub 3}, Rb{sub 2}O-SiO{sub 2}-B{sub 2}O{sub 3}, and Cs{sub 2}O-SiO{sub 2}-B{sub 2}O{sub 3}) were examined. Their mixing effects are currently under investigation.

  1. Development of Vitrification Process and Glass Formulation for Nuclear Waste Conditioning

    SciTech Connect

    Petitjean, V.; Fillet, C.; Boen, R.; Veyer, C.; Flament, T.

    2002-02-26

    The vitrification of high-level waste is the internationally recognized standard to minimize the impact to the environment resulting from waste disposal as well as to minimize the volume of conditioned waste to be disposed of. COGEMA has been vitrifying high-level waste industrially for over 20 years and is currently operating three commercial vitrification facilities based on a hot metal crucible technology, with outstanding records of safety, reliability and product quality. To further increase the performance of vitrification facilities, CEA and COGEMA have been developing the cold crucible melter technology since the beginning of the 1980s. This type of melter is characterized by a virtually unlimited equipment service life and a great flexibility in dealing with various types of waste and allowing development of high temperature matrices. In complement of and in parallel with the vitrification process, a glass formulation methodology has been developed by the CEA in order to tailor matrices for the wastes to be conditioned while providing the best adaptation to the processing technology. The development of a glass formulation is a trade-off between material properties and qualities, technical feasibility, and disposal safety criteria. It involves non-radioactive and radioactive laboratories in order to achieve a comprehensive matrix qualification. Several glasses and glass ceramics have thus been studied by the CEA to be compliant with industrial needs and waste characteristics: glasses or other matrices for a large spectrum of fission products, or for high contents of specifics elements such as sodium, phosphate, iron, molybdenum, or actinides. New glasses or glass-ceramics designed to minimize the final wasteform volume for solutions produced during the reprocessing of high burnup fuels or to treat legacy wastes are now under development and take benefit from the latest CEA hot-laboratories and technology development. The paper presents the CEA state-of-the-art in developing matrices or glasses and provides several examples.

  2. Kinetics of Cold-Cap Reactions for Vitrification of Nuclear Waste Glass Based on Simultaneous Differential Scanning Calorimetry - Thermogravimetry (DSC-TGA) and Evolved Gas Analysis (EGA)

    SciTech Connect

    Rodriguez, Carmen P.; Pierce, David A.; Schweiger, Michael J.; Kruger, Albert A.; Chun, Jaehun; Hrma, Pavel R.

    2013-12-03

    For vitrifying nuclear waste glass, the feed, a mixture of waste with glass-forming and modifying additives, is charged onto the cold cap that covers 90-100% of the melt surface. The cold cap consists of a layer of reacting molten glass floating on the surface of the melt in an all-electric, continuous glass melter. As the feed moves through the cold cap, it undergoes chemical reactions and phase transitions through which it is converted to molten glass that moves from the cold cap into the melt pool. The process involves a series of reactions that generate multiple gases and subsequent mass loss and foaming significantly influence the mass and heat transfers. The rate of glass melting, which is greatly influenced by mass and heat transfers, affects the vitrification process and the efficiency of the immobilization of nuclear waste. We studied the cold-cap reactions of a representative waste glass feed using both the simultaneous differential scanning calorimetry thermogravimetry (DSC-TGA) and the thermogravimetry coupled with gas chromatography-mass spectrometer (TGA-GC-MS) as complementary tools to perform evolved gas analysis (EGA). Analyses from DSC-TGA and EGA on the cold-cap reactions provide a key element for the development of an advanced cold-cap model. It also helps to formulate melter feeds for higher production rate.

  3. Minor component study for simulated high-level nuclear waste glasses (Draft)

    SciTech Connect

    Li, H.; Langowskim, M.H.; Hrma, P.R.; Schweiger, M.J.; Vienna, J.D.; Smith, D.E.

    1996-02-01

    Hanford Site single-shell tank (SSI) and double-shell tank (DSI) wastes are planned to be separated into low activity (or low-level waste, LLW) and high activity (or high-level waste, HLW) fractions, and to be vitrified for disposal. Formulation of HLW glass must comply with glass processibility and durability requirements, including constraints on melt viscosity, electrical conductivity, liquidus temperature, tendency for phase segregation on the molten glass surface, and chemical durability of the final waste form. A wide variety of HLW compositions are expected to be vitrified. In addition these wastes will likely vary in composition from current estimates. High concentrations of certain troublesome components, such as sulfate, phosphate, and chrome, raise concerns about their potential hinderance to the waste vitrification process. For example, phosphate segregation in the cold cap (the layer of feed on top of the glass melt) in a Joule-heated melter may inhibit the melting process (Bunnell, 1988). This has been reported during a pilot-scale ceramic melter run, PSCM-19, (Perez, 1985). Molten salt segregation of either sulfate or chromate is also hazardous to the waste vitrification process. Excessive (Cr, Fe, Mn, Ni) spinel crystal formation in molten glass can also be detrimental to melter operation.

  4. Deuteron NMR (Nuclear Magnetic Resonance) in relation to the glass transition in polymers

    NASA Technical Reports Server (NTRS)

    Roessler, E.; Sillescu, H.; Spiess, H. W.; Wallwitz, R.

    1983-01-01

    H-2NMR is introduced as a tool for investigating slow molecular motion in the glass transition region of amorphous polymers. In particular, we compare H-2 spin alignment echo spectra of chain deuterated polystyrene with model calculations for restricted rotational Brownian motion. Molecular motion in the polyztyrene-toluene system has been investigated by analyzing H-2NMR of partially deuterated polystyrene and toluene, respectively. The diluent mobility in the mixed glass has been decomposed into solid and liquid components where the respective average correlation times differ by more than 5 decades.

  5. ANNUAL REPORT. IRON PHOSPHATE GLASSES: AN ALTERNATIVE FOR VITRIFYING CERTAIN NUCLEAR WASTES

    EPA Science Inventory

    The two multifaceted objectives of this research project are to (1) investigate the feasibility of vitrifying 2 or 3 high priority wastes, as identified by the Tank Focus Area group, using iron phosphate glasses (i.e., determine chemical durability as a function of waste loading,...

  6. New functionality of chalcogenide glasses for radiation sensing of nuclear wastes.

    PubMed

    Ailavajhala, M S; Gonzalez-Velo, Y; Poweleit, C D; Barnaby, H J; Kozicki, M N; Butt, D P; Mitkova, M

    2014-03-30

    Data about gamma radiation induced effects in Ge40Se60 chalcogenide thin films and radiation induced silver diffusion within these are presented. Blanket films and devices were created to study the structural changes, diffusion products, and device performance. Raman spectroscopy, X-ray diffraction, current vs. voltage (I-V) and impedance measurements expound the behavior of Ge40Se60 glass and silver diffusion within this glass under radiation. Raman study shows that there is a decrease in the area ratio between edge shared and corner shared structural units revealing structural reorganization occurring in the glasses as a result of gamma radiation. X-ray diffraction studies revealed that with sufficiently radiation dose it is also possible to create Ag2Se in selenium-depleted systems. Oxidation of the Ge enriched chalcogenide backbone is confirmed through the electrical performance of the sensing elements based on these films. Combination of these structural and diffusion products influences the device performance. The I-V behavior is characterized by increase in current and then stabilization as a function of radiation dose. Additionally, device modeling is also presented using Silvaco software and analytical methods to shed light on the device behavior. This type of sensor design and material characterizations facilitate in improving the radiation sensing capabilities of silver containing chalcogenide glass thin films. PMID:24332317

  7. Cold-cap reactions in vitrification of nuclear waste glass: experiments and modeling

    SciTech Connect

    Chun, Jaehun; Pierce, David A.; Pokorny, Richard; Hrma, Pavel R.

    2013-05-01

    Cold-cap reactions are multiple overlapping reactions that occur in the waste-glass melter during the vitrification process when the melter feed is being converted to molten glass. In this study, we used differential scanning calorimetry (DSC) to investigate cold-cap reactions in a high-alumina high-level waste melter feed. To separate the reaction heat from both sensible heat and experimental instability, we employed the run/rerun method, which enabled us to define the degree of conversion based on the reaction heat and to estimate the heat capacity of the reacting feed. Assuming that the reactions are nearly independent and can be approximated by the nth order kinetics, we obtained the kinetic parameters using the Kissinger method combined with least squares analysis. The resulting mathematical simulation of the cold-cap reactions provides a key element for the development of an advanced cold-cap model.

  8. Development and testing of matrices for the encapsulation of glass and ceramic nuclear waste forms.

    SciTech Connect

    Wald, J.W.; Brite, D.W.; Gurwell, W.E.; Buckwalter, C.Q.; Bunnell, L.R.; Gray, W.J.; Blair, H.T.; Rusin, J.M.

    1982-02-01

    This report details the results of research on the matrix encapsulation of high level wastes at PML over the past few years. The demonstrations and tests described were designed to illustrate how the waste materials are effected when encapsulated in an inert matrix. Candidate materials evaluated for potential use as matrices for encapslation of pelletized ceramics or glass marbles were categorized into four groups: metals, glasses, ceramics, and graphite. Two processing techniques, casting and hot pressing, were investigated as the most promising methods of formation or densification of the matrices. The major results reported deal with the development aspects. However, chemical durability tests (leach tests) of the matrix materials themselves and matrix-waste form composites are also reported. Matrix waste forms can provide a low porosity, waste-free barrier resulting in increased leach protection, higher impact strength and improved thermal conductivity compared to unencapsulated glass or ceramic waste materials. Glass marbles encapsulated in a lead matrix offer the most significant improvement in waste form stability of all combinations evaluated. This form represents a readily demonstrable process that provides high thermal conductivity, mechanical shock resistance, radiation shielding and increased chemical durability through both a chemical passivation mechanism and as a physical barrier. Other durable matrix waste forms evaluated, applicable primarily to ceramic pellets, involved hot-pressed titanium or TiO/sub 2/ materials. In the processing of these forms, near 100% dense matrices were obtained. The matrix materials had excellent compatibility with the waste materials and superior potential chemical durability. Cracking of the hot-pressed ceramic matrix forms, in general, prevented the realization of their optimum properties.

  9. Processing constraints on high-level nuclear waste glasses for Hanford Waste Vitrification Plant

    SciTech Connect

    Hrma, P.R.

    1993-09-01

    The work presented in this paper is a part of a major technology program supported by the U.S. Department of Energy (DOE) in preparation for the planned operation of the Hanford Waste Vitrification Plant (HWVP). Because composition of Hanford waste varies greatly, processability is a major concern for successful vitrification. This paper briefly surveys general aspects of waste glass processability and then discusses their ramifications for specific examples of Hanford waste streams.

  10. Sulfur incorporation in high level nuclear waste glass: A S K-edge XAFS investigation

    NASA Astrophysics Data System (ADS)

    Brendebach, B.; Denecke, M. A.; Roth, G.; Weisenburger, S.

    2009-11-01

    We perform X-ray absorption fine structure (XAFS) spectroscopy measurements at the sulfur K-edge to elucidate the electronic and geometric bonding of sulfur atoms in borosilicate glass used for the vitrification of high level radioactive liquid waste. The sulfur is incorporated as sulfate, most probably as sodium sulfate, which can be deduced from the X-ray absorption near edge structure (XANES) by fingerprint comparison with reference compounds. This finding is backed up by Raman spectroscopy investigation. In the extended XAFS data, no second shell beyond the first oxygen layer is visible. We argue that this is due to the sulfate being present as small clusters located into voids of the borosilicate network. Hence, destructive interference of the variable surrounding prohibits the presence of higher shell signals. The knowledge of the sulfur bonding characteristics is essential for further optimization of the glass composition and to balance the requirements of the process and glass quality parameters, viscosity and electrical resistivity on one side, waste loading and sulfur uptake on the other side.

  11. Numerical simulation of high-level radioactive nuclear waste glass production

    SciTech Connect

    Choi, I.G.; Ungan, A.

    1991-12-31

    Vitrification of radioactive waste has become an international approach for converting highly radioactive wastes into a durable solid prior to placing them in a permanent disposal repository. The technology for the process is not new. The conversion melter is a direct descendant of all electric melters used for manufacturing of some commercial glass types. Therefore, the vitrification process of radioactive wastes inherits typical problems of all electric furnaces and creates some other specific problems such as noble metal sedimentation. The noble metals and nickel sulfides in the melter are heavier than molten glass and have a low solubility. In a reducing condition, these metals amalgamate and tend to settle on the melter floor. The metal deposit resulting from this settling has a potential to short circuit the melter. The objective of this paper is to identify the typical problems that have been encountered in the waste melter operations and to address how these problems can be tackled using state-of-the-art numerical simulation techniques. It is believed that the large amount of pilot-scale melter experience throughout the world, combined with the knowledge gained from state-of-the-art computer modeling techniques would give assurance that the existing and future radioactive wastes can be effectively converted into a durable glass material and safely placed in a permanent repository.

  12. Numerical simulation of high-level radioactive nuclear waste glass production

    SciTech Connect

    Choi, I.G. ); Ungan, A. . Dept. of Mechanical Engineering)

    1991-01-01

    Vitrification of radioactive waste has become an international approach for converting highly radioactive wastes into a durable solid prior to placing them in a permanent disposal repository. The technology for the process is not new. The conversion melter is a direct descendant of all electric melters used for manufacturing of some commercial glass types. Therefore, the vitrification process of radioactive wastes inherits typical problems of all electric furnaces and creates some other specific problems such as noble metal sedimentation. The noble metals and nickel sulfides in the melter are heavier than molten glass and have a low solubility. In a reducing condition, these metals amalgamate and tend to settle on the melter floor. The metal deposit resulting from this settling has a potential to short circuit the melter. The objective of this paper is to identify the typical problems that have been encountered in the waste melter operations and to address how these problems can be tackled using state-of-the-art numerical simulation techniques. It is believed that the large amount of pilot-scale melter experience throughout the world, combined with the knowledge gained from state-of-the-art computer modeling techniques would give assurance that the existing and future radioactive wastes can be effectively converted into a durable glass material and safely placed in a permanent repository.

  13. Development of a device for helium thermal diffusion investigations by IBA in self-irradiated nuclear glass

    NASA Astrophysics Data System (ADS)

    Raepsaet, C.; Peuget, S.; Khodja, H.; Gutierrez, G.; Hoarau, J.; Sauvage, T.

    2014-07-01

    To minimize the amount of nuclear waste issuing from the nuclear power plants, the solution adopted in France consists in the reprocessing of spent fuel to isolate long lived and high level radioactive waste (minor actinides and fission products). They are incorporated into a glassy matrix in order to be placed in dedicated long-term disposal repository. The confinement of the radioelements depends strongly on the integrity of the glassy matrix which could be damaged by the radiations and the generation of helium produced by ?-decays of the minor actinides. In the past few years, several studies were conducted in order to understand the behaviour of helium, especially its thermal diffusion into the glassy matrix [1-3]. However none were conducted on self-irradiated samples and a validation on radioactive glasses and in the temperature range of the repository conditions is still needed. For this purpose, a specific setup was developed on the analysis chamber of the nuclear microprobe dedicated to radioactive samples in Saclay [4]. The temperature of the sample is controlled during all the experiment, in the range from 143 to 323 K; 3He ions are implanted at low temperature. Helium profiles are measured at low temperature using the 3He(d,p)4He reaction, as-implanted and after several stages of annealing. We will present the developed setup and show the preliminary results of the measurements made on non-active samples.

  14. Quantitative fluid inclusion gas analysis of airburst, nuclear, impact and fulgurite glasses.

    SciTech Connect

    Parnell, John; Newsom, Horton E.; Blamey, Nigel J. F.; Boslough, Mark Bruce Elrick

    2010-10-01

    We present quantitative fluid inclusion gas analysis on a suite of violently-formed glasses. We used the incremental crush mass spectrometry method (Norman & Blamey, 2001) to analyze eight pieces of Libyan Desert Glass (LDG). As potential analogues we also analyzed trinitite, three impact crater glasses, and three fulgurites. The 'clear' LDG has the lowest CO{sub 2} content and O{sub 2}/Ar ratios are two orders of magnitude lower than atmospheric. The 'foamy' glass samples have heterogeneous CO{sub 2} contents and O{sub 2}/Ar ratios. N{sub 2}/Ar ratios are similar to atmospheric (83.6). H{sub 2} and He are elevated but it is difficult to confirm whether they are of terrestrial or meteoritic origin. Combustion cannot account for oxygen depletion that matches the amount of CO{sub 2} produced. An alternative mechanism is required that removes oxygen without producing CO{sub 2}. Trinitite has exceedingly high CO{sub 2} which we attribute to carbonate breakdown of the caliche at ground zero. The O{sub 2}/Ar ratio for trinitite is lower than atmospheric but higher than all LDG samples. N{sub 2}/Ar ratios closely match atmospheric. Samples from Lonar, Henbury and Aouelloul impact craters have atmospheric N{sub 2}/Ar ratios. O{sub 2}/Ar ratios at Lonar and Henbury are 9.5 to 9.9 whereas the O{sub 2}/Ar ratio is 0.1 for the Aouelloul sample. In most fulgurites the N{sub 2}/Ar ratio is higher than atmospheric, possibly due to interference from CO. Oxygen ranges from 1.3 to 19.3%. Gas signatures of LDG inclusions neither match those from the craters, trinitite nor fulgurites. It is difficult to explain both the observed depletion of oxygen in the LDG and a CO{sub 2} level that is lower than it would be if the CO{sub 2} were simply a product of hydrocarbon combustion in air. One possible mechanism for oxygen depletion is that as air turbulently mixed with a hot jet of vaporized asteroid from an airburst and expanded, the atmospheric oxygen reacted with the metal vapor to form metal oxides that condensed. This observation is compatible with the model of Boslough & Crawford (2008) who suggest that an airburst incinerates organic materials over a large area, melting surface materials that then quench to form glass. Bubbles would contain a mixture of pre-existing atmosphere with combustion products from organic material and products of the reaction between vaporized cosmic materials (including metals) and terrestrial surface and atmosphere.

  15. The use of natural and archeological analogues for understanding the long-term behavior of nuclear glasses

    NASA Astrophysics Data System (ADS)

    Libourel, Guy; Verney-Carron, Aurelie; Morlok, Andreas; Gin, Stéphane; Sterpenich, Jérôme; Michelin, Anne; Neff, Delphine; Dillmann, Philippe

    2011-02-01

    The knowledge of the long-term behavior of nuclear waste in anticipation of ultimate disposal in a deep geological formation is of prime importance in a waste management strategy. If phenomenological models have been developed to predict the long-term behavior of these materials, validating these models remains a challenge, when considering the time scale of radioactive decay of radionuclides of environmental concern, typically 10 4-10 5 yrs. Here we show how natural or archaeological analogues provide critical constraints not only on the phenomenology of glass alteration and the mechanisms involved, but also on the ability of experimental short-term data to predict long-term alteration in complex environments.

  16. Biological effect of Acidithiobacillus thiooxidans on some potentially toxic elements during alteration of SON 68 nuclear glass

    NASA Astrophysics Data System (ADS)

    Bachelet, M.; Crovisier, J. L.; Stille, P.; Vuilleumier, S.; Geoffroy, V.

    2009-04-01

    Although underground nuclear waste repositories are not expected to be favourable places for microbial activity, one should not exclude localized action of extremophilic bacteria on some materials involved in the storage concept. Among endogenous or accidentally introduced acidophiles, some are susceptible to lead to a locally drastic decreased in pH, with potential consequences on materials corrosion. Experiments were performed with Acidithiobacillus thiooxidans on 100-125 m french reference nuclear glass SON68 grains in a mineral medium under static conditions during 60 days at 25degC. Growth medium was periodically renewed and analyzed by ICP-AES and ICP-MS spectrometry for both major, trace and ultra-trace elements. Biofilm formation was evidenced by confocal laser microscopy, staining DNA with ethidium bromide and exopolysaccharides with calcofluor white. Biofilm thickness around material grains exceeded 20 m under the chosen experimental conditions. It can be noticed that while numerous studies on biofilm formation upon interaction between Acidithiobacillus ferrooxidans and materials are found in the literature, evidence for biofilm formation is still scarce for the case of the acidophilic bacterium A. thiooxidans. Presence of biofilm is a key parameter for material alteration at the solid/solution interface in biotic systems. Indeed, various constitutive elements of materials trapped in the polyanionic polymer of biofilm may also influence the alteration process. In particular, biofilm may reduce the alteration rate of materials by forming a protective barrier at their surface (Aouad et al., 2008). In this study, glass alteration rates, determined using strontium as tracer, showed that the progressive formation of a biofilm on the surface of glass has a protective effect against its alteration. Uranium and rare earth elements (REE) are efficiently trapped in the biogenic compartment of the system (exopolysaccharides + bacterial cells). Besides, the ratio biotic/abiotic concentrations of REE and U in the leachant decreases with increasing time which seems to indicate a good capacity of EPS for long term trapping of potentially toxic elements. Aouad G., Crovisier J.-L., Damidot D., Stille P., Hutchens E., Mutterer J., Meyer J.-M., and Geoffroy V. A. (2008) Interactions between municipal solid waste incinerator bottom ash and bacteria (Pseudomonas aeruginosa). Science of The Total Environment 393((2-3)), 385-393.

  17. RHENIUM SOLUBILITY IN BOROSILICATE NUCLEAR WASTE GLASS IMPLICATIONS FOR THE PROCESSING AND IMMOBILIZATION OF TECHNETIUM-99 (AND SUPPORTING INFORMATION WITH GRAPHICAL ABSTRACT)

    SciTech Connect

    AA KRUGER; A GOEL; CP RODRIGUEZ; JS MCCLOY; MJ SCHWEIGER; WW LUKENS; JR, BJ RILEY; D KIM; M LIEZERS; P HRMA

    2012-08-13

    The immobilization of 99Tc in a suitable host matrix has proved a challenging task for researchers in the nuclear waste community around the world. At the Hanford site in Washington State in the U.S., the total amount of 99Tc in low-activity waste (LAW) is {approx} 1,300 kg and the current strategy is to immobilize the 99Tc in borosilicate glass with vitrification. In this context, the present article reports on the solubility and retention of rhenium, a nonradioactive surrogate for 99Tc, in a LAW sodium borosilicate glass. Due to the radioactive nature of technetium, rhenium was chosen as a simulant because of previously established similarities in ionic radii and other chemical aspects. The glasses containing target Re concentrations varying from 0 to10,000 ppm by mass were synthesized in vacuum-sealed quartz ampoules to minimize the loss of Re by volatilization during melting at 1000 DC. The rhenium was found to be present predominantly as Re7 + in all the glasses as observed by X-ray absorption near-edge structure (XANES). The solubility of Re in borosilicate glasses was determined to be {approx}3,000 ppm (by mass) using inductively coupled plasma-optical emission spectroscopy (ICP-OES). At higher rhenium concentrations, some additional material was retained in the glasses in the form of alkali perrhenate crystalline inclusions detected by X-ray diffraction (XRD) and laser ablation-ICP mass spectrometry (LA-ICP-MS). Assuming justifiably substantial similarities between Re7 + and Tc 7+ behavior in this glass system, these results implied that the processing and immobilization of 99Tc from radioactive wastes should not be limited by the solubility of 99Tc in borosilicate LAW glasses.

  18. CHEMICAL DECOMPOSITION OF HIGH-LEVEL NUCLEAR WASTE STORAGE/DISPOSAL GLASSES UNDER IRRADIATION

    EPA Science Inventory

    The Offices of Energy Research and Environmental Management are immediately concerned with the development of storage/immobilization media for high-level nuclear wastes and excess weapons plutonium. These media must be stable and free of risk to the public or to the environment f...

  19. Nuclear Spin Lattice Relaxation and Conductivity Studies of the Non-Arrhenius Conductivity Behavior in Lithium Fast Ion Conducting Sulfide Glasses

    SciTech Connect

    Benjamin Michael Meyer

    2003-05-31

    As time progresses, the world is using up more of the planet's natural resources. Without technological advances, the day will eventually arrive when these natural resources will no longer be sufficient to supply all of the energy needs. As a result, society is seeing a push for the development of alternative fuel sources such as wind power, solar power, fuel cells, and etc. These pursuits are even occurring in the state of Iowa with increasing social pressure to incorporate larger percentages of ethanol in gasoline. Consumers are increasingly demanding that energy sources be more powerful, more durable, and, ultimately, more cost efficient. Fast Ionic Conducting (FIC) glasses are a material that offers great potential for the development of new batteries and/or fuel cells to help inspire the energy density of battery power supplies. This dissertation probes the mechanisms by which ions conduct in these glasses. A variety of different experimental techniques give a better understanding of the interesting materials science taking place within these systems. This dissertation discusses Nuclear Magnetic Resonance (NMR) techniques performed on FIC glasses over the past few years. These NMR results have been complimented with other measurement techniques, primarily impedance spectroscopy, to develop models that describe the mechanisms by which ionic conduction takes place and the dependence of the ion dynamics on the local structure of the glass. The aim of these measurements was to probe the cause of a non-Arrhenius behavior of the conductivity which has been seen at high temperatures in the silver thio-borosilicate glasses. One aspect that will be addressed is if this behavior is unique to silver containing fast ion conducting glasses. more specifically, this study will determine if a non-Arrhenius correlation time, {tau}, can be observed in the Nuclear Spin Lattice Relaxation (NSLR) measurements. If so, then can this behavior be modeled with a new single distribution of activation energies (DAE) to calculate the corresponding conductivity and relaxation rates as a function of temperature and frequency?

  20. Quasicrystalline Approach to Prediting the Spinel-Nepheline Liquidus: Application to Nuclear Waste Glass Processing

    SciTech Connect

    Jantzen, Carol

    2005-10-10

    The crystal-melt equilibria in complex fifteen component melts are modeled based on quasicrystalline concepts. A pseudobinary phase diagram between acmite (which melts incongruently to a transition metal ferrite spinel) and nepheline is defined. The pseudobinary lies within the Al{sub 2}O{sub 3}-Fe{sub 2}O{sub 3}-Na{sub 2}O-SiO{sub 2} quaternary system that defines the crystallization of basalt glass melts. The pseudobinary provides the partitioning of species between the melt and the primary liquidus phases. The medium range order of the melt and the melt-crystal exchange equilibria are defined based on a constrained mathematical treatment that considers the crystallochemical coordination of the elemental species in acmite and nepheline. The liquidus phases that form are shown to be governed by the melt polymerization and the octahedral site preference energies. This quasicrystalline liquidus model has been used to prevent unwanted crystallization in the world's largest high level waste (HLW) melter for the past three years while allowing >10 wt% higher waste loadings to be processed.

  1. Initial comparison of leach behavior between fully radioactive and simulated nuclear waste glass through long-term testing: Part 2, Reacted layer analysis

    SciTech Connect

    Bates, J.K.; Feng, X.; Bradley, C.R.; Buck, E.C.

    1992-04-01

    An initial comparison of glass behavior of simulated nuclear waste glasses has been made through long-term testing of general glass types SRL165, SRL131 and SRL200. The data demonstrate that up to 560 days at S/V of 2000/m, the reacted layers consist of one outer clay layer, which is undetermined by discontinuous etch pits. The regions between the etch pits are alkali depleted. The surface layer becomes thicker as test duration progresses and the reacted layer after the same test time is thinner at higher S/V than at lower S/V. The relative glass durability measured by the thickness of the reacted layer is 165/42S > 131/11S > 200S, which is consistent with solution analyses. In general, the reacted layers on all glass compositions are poorly crystallized which makes the clay identification difficult. The diffraction spacings and EDS compositions for 131/11S and 200S, although not unique to, are consistent with Na (or Ca-) montmorillonite or nontronite. Both of these are dioctahedral smectite.

  2. Initial comparison of leach behavior between fully radioactive and simulated nuclear waste glass through long-term testing: Part 2, Reacted layer analysis

    SciTech Connect

    Bates, J.K.; Feng, X.; Bradley, C.R.; Buck, E.C.

    1992-01-01

    An initial comparison of glass behavior of simulated nuclear waste glasses has been made through long-term testing of general glass types SRL165, SRL131 and SRL200. The data demonstrate that up to 560 days at S/V of 2000/m, the reacted layers consist of one outer clay layer, which is undetermined by discontinuous etch pits. The regions between the etch pits are alkali depleted. The surface layer becomes thicker as test duration progresses and the reacted layer after the same test time is thinner at higher S/V than at lower S/V. The relative glass durability measured by the thickness of the reacted layer is 165/42S > 131/11S > 200S, which is consistent with solution analyses. In general, the reacted layers on all glass compositions are poorly crystallized which makes the clay identification difficult. The diffraction spacings and EDS compositions for 131/11S and 200S, although not unique to, are consistent with Na (or Ca-) montmorillonite or nontronite. Both of these are dioctahedral smectite.

  3. Thermal Conductivity of Glasses Induced by Nuclear Quadrupole Interaction at Ultra Low Temperatures

    NASA Astrophysics Data System (ADS)

    Polishchuk, I. Y.; Burin, A. L.

    2011-03-01

    It is investigated how nuclear degrees of freedom of tunneling system (TS) inherent in amorphous solids influence its acoustic properties. It was shown in our previous papers that below 10 mK nuclear quadrupole interaction breaks down the coherent tunneling. This phenomenon results in appearance of the quasi-gap in the distribution function for the tunneling amplitude splitting. The quasi-gap is responsible for the plateau in the temperature dependence of the real part of a dielectric permittivity or speed of sound. In this paper we are interested in ultrasonic absorption and thermal conductivity which are intimately connected. We demonstrate that there exists a temperature interval in a millikelvin region where the sound absorption behavior changes drastically from the behavior predicted by the standard tunneling model (STM). In particular, the sound absorption increases approximately by an order of magnitude. Since in the millikelvin region the heat transport is due to acoustic phonons, the thermal conductivity also should demonstrate a strong increase as compared to standard tunneling model. The application of a strong magnetic field is known to restore the coherent tunneling and the standard distribution for the tunneling splitting amplitude. Thus, one can expect that in a strong magnetic field the thermal conductivity should drop in the temperature interval where the coherent tunneling was initially destroyed.

  4. Glass science tutorial: Lecture No. 7, Waste glass technology for Hanford

    SciTech Connect

    Kruger, A.A.

    1995-07-01

    This paper presents the details of the waste glass tutorial session that was held to promote knowledge of waste glass technology and how this can be used at the Hanford Reservation. Topics discussed include: glass properties; statistical approach to glass development; processing properties of nuclear waste glass; glass composition and the effects of composition on durability; model comparisons of free energy of hydration; LLW glass structure; glass crystallization; amorphous phase separation; corrosion of refractories and electrodes in waste glass melters; and glass formulation for maximum waste loading.

  5. Effect of different glasses in glass bonded zeolite

    SciTech Connect

    Lewis, M.A.; Ackerman, J.P.; Verma, S.

    1995-05-01

    A mineral waste form has been developed for chloride waste salt generated during the pyrochemical treatment of spent nuclear fuel. The waste form consists of salt-occluded zeolite powders bound within a glass matrix. The zeolite contains the salt and immobilizes the fission products. The zeolite powders are hot pressed to form a mechanically stable, durable glass bonded zeolite. Further development of glass bonded zeolite as a waste form requires an understanding of the interaction between the glass and the zeolite. Properties of the glass that enhance binding and durability of the glass bonded zeolite need to be identified. Three types of glass, boroaluminosilicate, soda-lime silicate, and high silica glasses, have a range of properties and are now being investigated. Each glass was hot pressed by itself and with an equal amount of zeolite. MCC-1 leach tests were run on both. Soda-lime silicate and high silica glasses did not give a durable glass bonded zeolite. Boroaluminosilicate glasses rich in alkaline earths did bind the zeolite and gave a durable glass bonded zeolite. Scanning electron micrographs suggest that the boroaluminosilicate glasses wetted the zeolite powders better than the other glasses. Development of the glass bonded zeolite as a waste form for chloride waste salt is continuing.

  6. INTERNATIONAL STUDIES OF ENHANCED WASTE LOADING AND IMPROVED MELT RATE FOR HIGH ALUMINA CONCENTRATION NUCLEAR WASTE GLASSES

    SciTech Connect

    Fox, K; David Peeler, D; James Marra, J

    2008-09-11

    The goal of this study was to determine the impacts of glass compositions with high aluminum concentrations on melter performance, crystallization and chemical durability for Savannah River Site (SRS) and Hanford waste streams. Glass compositions for Hanford targeted both high aluminum concentrations in waste sludge and a high waste loading in the glass. Compositions for SRS targeted Sludge Batch 5, the next sludge batch to be processed in the Defense Waste Processing Facility (DWPF), which also has a relatively high aluminum concentration. Three frits were selected for combination with the SRS waste to evaluate their impact on melt rate. The glasses were melted in two small-scale test melters at the V. G. Khlopin Radium Institute. The results showed varying degrees of spinel formation in each of the glasses. Some improvements in melt rate were made by tailoring the frit composition for the SRS feeds. All of the Hanford and SRS compositions had acceptable chemical durability.

  7. Intrinsic dosimetry of glass containers used to transport nuclear materials: Potential implications to the fields of waste management and nuclear forensics

    SciTech Connect

    Schwantes, Jon M.; Miller, Steve D.; Piper, Roman K.; Murphy, Mark K.; Amonette, James E.; Bonde, Steven E.; Duckworth, Douglas C.

    2009-04-12

    Thermoluminescence (TL) and Electron Paramagnetic Resonance (EPR) dosimetry were used to measure dose effects in borosilicate glass with time, from 10 min to w60 days following exposure to a dose of up to 100 Gy. TL and EPR results were consistent and performed similarly, with both techniques capable of achieving an estimated limit of detection of between 0.5 and 1 Gy. Three peaks were identified in the TL glow curve at roughly 110 C, 205 C, and 225 C. The intensity of the 205 C peak was the dominant peak over the time period of this study. The stability of all of the peaks with time since irradiation increased with their corresponding temperature and no significant variation was observed in the glow curve response to a specified total dose attained at different dose rates. The intensity of the 205 C peak decreased logarithmically with time regardless of total dose. Based upon a conservative limit of detection of 3.3 Gy, a 100 Gy dose would still be detected 2.7E3 years after exposure. Here, we introduce the concept of intrinsic dosimetry, the measurement of the total absorbed dose received by the walls of a container containing radioactive material. The foreseen advantage of intrinsic dosimetry comes from considering the measured absorbed dose received by containers in concert with the characteristics (amount, type) of the source of that dose, the radioactive material contained within the walls of the container, in order to provide enhanced information about the history of an unknown sample in question. Three hypothetical scenarios are presented to introduce this method and to illustrate how intrinsic dosimetry might benefit the fields of nuclear forensics and waste management.

  8. Effects of neutron irradiation on glass ceramics as pressure-less joining materials for SiC based components for nuclear applications

    NASA Astrophysics Data System (ADS)

    Ferraris, M.; Casalegno, V.; Rizzo, S.; Salvo, M.; Van Staveren, T. O.; Matejicek, J.

    2012-10-01

    This paper reports on the microstructure and properties of two glass-ceramics based on SiO2-Al2O3-MgO (SAMg) and SiO2-Al2O3-Y2O3 (SAY), which have been designed to be used as pressure-less low activation joining materials for SiC/SiC and SiC based components for nuclear applications. Glass-ceramic pellets (SAY and SAMg) were irradiated for approximately 1 year in the reactor core of the LVR-15 research reactor at Nuclear Research Institute Rez, Czech Republic, at about 50 °C, 6.92 × 1024 n/m2 (E > 1 MeV, about 1 dpa in steel); SiC/SiC composites joined by SAY were irradiated about 1 year at High Flux Reactor (HFR), Petten, The Netherlands, 550 °C, 9-11 × 1024 n/m2 (E > 1 MeV, about 1.4-1.8 dpa in C), 600 °C, 16-22 × 1024 n/m2 (E > 1 MeV, about 2.6-3.3 dpa in C) and 820 °C 31-32 × 1024 n/m2(E > 1 MeV, about 5 dpa in C). Optical microscopy with image analysis and scanning electron microscopy (SEM) with X-ray microanalysis (EDS) were used to investigate the glass-ceramics morphology and composition, showing a remarkable similarity before and after neutron irradiation for both glass-ceramics. Comparison of bending strength for irradiated and non-irradiated SAY joined SiC/SiC indicate that the mechanical strength is unaffected by irradiation at these conditions.

  9. Secondary phase formation and the microstructural evolution of surface layers during vapor phase alteration of the French SON 68 nuclear waste glass at 200{degrees}C

    SciTech Connect

    Gong, W.L.; Ewing, R.C.; Wang, L.M.

    1995-12-31

    The SON 68 inactive {open_quotes}R7T7{close_quotes} composition is the French reference glass for the LWR nuclear waste glass. Vapor phase alteration was used to accelerate the reaction progress of glass corrosion and to develop the characteristic suite of secondary, alteration phases. Extensive solid-state characterization (AEM/SEM/HRTEM) was completed on six inactive R7T7 waste glasses which were altered in the presence of saturated water vapor (200{degrees}C) for 91, 241, 908, 1000, 1013, and 1021 days. The AEM samples were examined in cross-section (lattice-fringe imaging, micro-diffraction, and quantitative thin-film EDS analysis). The glass monoliths were invariably covered with a thin altered rind. The layer became thicker with time: 0.5 {mu}m for 22 days; 4 {mu}m for 91 days; 6 {mu}m for 241 days; 10 {mu}m for 908 days; 26 {mu}m for 1013 days; and <35 {mu}m for 1021 days. The composite alteration layer of the SON 68 samples is at least four time less thick than that of the SRL 131 glass composition. Six distinctive zones, based on phase chemistry and microstructure, were distinguished within the well-developed surface layers. Numerous crystalline phases such as analcime, tobermorite, apatite, and weeksite were identified on the surfaces of the reacted glasses as precipitates. Two crystalline phases, Ag{sub 2}TeO{sub 3} and (Ca,Sr)Mo{sub 3}O{sub 9}(OH){sub 2}, were found within the inner zones of surface layers, and they must have nucleated in situ, indicating that Ag, Te, Sr, and Mo can be retained within the surface layer. The majority of the surface layer volume is composed of two morphologically and chemically different structures: one consists of well-crystallized fibrous smectite aggregates occurring along with cavities, the A-domain; and the other consists of poorly-crystallized regions containing needle-like smectite (montmorillonite) crystallites, a silica-rich amorphous matrix, and possibly ZrO{sub 2} particles, the B-domain.

  10. IR and Raman Spectroscopy of Sodium-Aluminophosphate Glasses for Immobilizing High-Level Wastes from Spent Nuclear Fuel Reprocessing

    NASA Astrophysics Data System (ADS)

    Stefanovsky, S. V.; Myasoedov, B. F.; Remizov, M. B.; Belanova, E. A.

    2014-09-01

    The structure of sodium-aluminophosphate glasses containing constituents of high-level wastes (cesium, magnesium, copper, and molybdenum oxides) from uranium-graphite reactors was studied by IR and Raman spectroscopy coupled with x-ray diffraction. The structural network was shown to be composed of short P-O chains with embedded AlO4 tetrahedra. Cross-linking by Mg2+ was possible in the Mg-bearing samples. The effect of the other oxides (Cs2O, MoO3, CuO) on the glass structure was negligible for the occurring amounts. The glasses devitrified partially upon quenching and more strongly upon annealing. This was reflected in splitting of the vibrational bands for bonds in the glass anionic structural motif.

  11. Dynamics of asymmetric non-polymeric binary glass formers—A nuclear magnetic resonance and dielectric spectroscopy study

    NASA Astrophysics Data System (ADS)

    Pötzschner, B.; Mohamed, F.; Lichtinger, A.; Bock, D.; Rössler, E. A.

    2015-10-01

    We study a dynamically asymmetric binary glass former with the low-Tg component m-tri-cresyl phosphate (m-TCP: Tg = 206 K) and a spirobichroman derivative as a non-polymeric high-Tg component (Tg = 382 K) by means of 1H nuclear magnetic resonance (NMR), 31P NMR, and dielectric spectroscopy which allow component-selectively probing the dynamics. The entire concentration range is covered, and two main relaxation processes with two Tg are identified, Tg1 and Tg2. The slower one is attributed to the high-Tg component (?1-process), and the faster one is related to the m-TCP molecules (?2-process). Yet, there are indications that a small fraction of m-TCP is associated also with the ?1-process. While the ?1-relaxation only weakly broadens upon adding m-TCP, the ?2-relaxation becomes extremely stretched leading to quasi-logarithmic correlation functions at low m-TCP concentrations—as probed by 31P NMR stimulated echo experiments. Frequency-temperature superposition does not apply for the ?2-process and it reflects an isotropic, liquid-like motion which is observed even below Tg1, i.e., in the matrix of the arrested high-Tg molecules. As proven by 2D 31P NMR, the corresponding dynamic heterogeneities are of transient nature, i.e., exchange occurs within the distribution G(ln??2). At Tg1 a crossover is found for the temperature dependence of (mean) ??2(T) from non-Arrhenius above to Arrhenius below Tg1 which is attributed to intrinsic confinement effects. This "fragile-to-strong" transition also leads to a re-decrease of Tg2(cm-TCP) at low concentration cm-TCP, i.e., a maximum is observed in Tg2(cm-TCP) while Tg1(cm-TCP) displays the well-known plasticizer effect. Although only non-polymeric components are involved, we re-discover essentially all features previously reported for polymer-plasticizer systems.

  12. Electron-nuclear double resonance study of molecular librations of nitroxides in molecular glasses: Quantum effects at low temperatures, comparison with low-frequency Raman scattering

    NASA Astrophysics Data System (ADS)

    Kulik, L. V.; Rapatsky, L. L.; Pivtsov, A. V.; Surovtsev, N. V.; Adichtchev, S. V.; Grigor'ev, I. A.; Dzuba, S. A.

    2009-08-01

    Pulsed electron-nuclear double resonance applied to N15 nitroxide spin probes in molecular glasses is shown to be very sensitive to measurement of the AXX principal value of the hyperfine interaction tensor. For molecules experiencing fast restricted orientational motions (molecular librations), this provides a precise tool to determine the motion-averaged ?AXX? value. For nitroxides in glycerol and o-terphenyl glasses, the observed ?AXX? temperature dependence below 40 K may be readily interpreted as arising from quantum effects in librations, when the thermal energy of a librating molecule becomes comparable with the elementary quantum of the oscillator. The estimated elementary quanta for nitroxide librations, ˜60 cm-1 in glycerol and ˜90 cm-1 in o-terphenyl, are found to match the characteristic frequencies of the vibrational spectral densities seen in low-frequency Raman scattering for these glasses. Above ˜80 K in glycerol and above ˜120 K in o-terphenyl, the ?AXX? temperature dependences manifest a kink with a slightly smaller slope than at lower temperatures.

  13. DEVELOPMENT OF GLASS COMPOSITIONS TO IMMOBILIZE ALKALI, ALKALINE EARTH, LANTHANIDE AND TRANSITION METAL FISSION PRODUCTS FROM NUCLEAR FUEL REPROCESSING

    SciTech Connect

    Marra, J.; Billings, A.

    2009-06-24

    The Advanced Fuel Cycle Initiative (AFCI) waste management strategy revolves around specific treatment of individual or groups of separated waste streams. A goal for the separations processes is to efficiently manage the waste to be dispositioned as high level radioactive waste. The Advanced Fuel Cycle Initiative (AFCI) baseline technology for immobilization of the lanthanide (Ln) and transition metal fission product (TM) wastes is vitrification into a borosilicate glass. A current interest is to evaluate the feasibility of vitrifying combined waste streams to most cost effectively immobilize the wastes resulting from aqueous fuel reprocessing. Studies showed that high waste loadings are achievable for the Ln only (Option 1) stream. Waste loadings in excess of 60 wt % (on a calcined oxide basis) were demonstrated via a lanthanide borosilicate (LaBS) glass. The resulting glasses had excellent relative durability as determined by the Product Consistency Test (PCT). For a combined Ln and TM waste stream glass (Option 2), noble metal solubility was found to limit waste loading. However, the measured PCT normalized elemental releases for this glass were at least an order of magnitude below that of Environmental Assessment (EA) glass. Current efforts to evaluate the feasibility of vitrifying combined Ln, TM, alkali (Cs is the primary radionuclide of concern) and alkaline earth (Sr is the primary radionuclide of concern) wastes (Option 3) have shown that these approaches are feasible. However, waste loading limitations with respect to heat load (Cs/Sr loading), molybdenum solubility and/or noble metal solubility will likely be realized and must be considered in determining the cost effectiveness of these approaches.

  14. DEVELOPMENT OF GLASS COMPOSITIONS TO IMMOBILIZE ALKALI, ALKALINE EARTH, LANTHANIDE AND TRANSITION METAL FISSION PRODUCTS FROM NUCLEAR FUEL REPROCESSING

    SciTech Connect

    Marra, James C.; Billings, Amanda Y.; Crum, Jarrod V.; Ryan, Joseph V.; Vienna, John D.

    2010-02-26

    The Advanced Fuel Cycle Initiative (AFCI) waste management strategy revolves around specific treatment of individual or groups of separated waste streams. A goal for the separations processes is to efficiently manage the waste to be dispositioned as high level radioactive waste. The Advanced Fuel Cycle Initiative (AFCI) baseline technology for immobilization of the lanthanide (Ln) and transition metal fission product (TM) wastes is vitrification into a borosilicate glass. A current interest is to evaluate the feasibility of vitrifying combined waste streams to most cost effectively immobilize the wastes resulting from aqueous fuel reprocessing. Studies showed that high waste loadings are achievable for the Ln only (Option 1) stream. Waste loadings in excess of 60 wt % (on a calcined oxide basis) were demonstrated via a lanthanide borosilicate (LaBS) glass. The resulting glasses had excellent relative durability as determined by the Product Consistency Test (PCT). For a combined Ln and TM waste stream glass (Option 2), noble metal solubility was found to limit waste loading. However, the measured PCT normalized elemental releases for this glass were at least an order of magnitude below that of Environmental Assessment (EA) glass. Current efforts to evaluate the feasibility of vitrifying combined Ln, TM, alkali (Cs is the primary radionuclide of concern) and alkaline earth (Sr is the primary radionuclide of concern) wastes (Option 3) have shown that these approaches are feasible. However, waste loading limitations with respect to heat load (Cs/Sr loading), molybdenum solubility and/or noble metal solubility will likely be realized and must be considered in determining the cost effectiveness of these approaches.

  15. Physics and chemistry of the transition of glass to authigenic minerals: State of Nevada, agency for nuclear projects/nuclear waste project office

    SciTech Connect

    Morgenstein, M.E.

    1984-11-01

    The purpose of this paper is to provide a basic review of the topic of volcanic-glass hydration and the diagenetic formation of authigenic minerals from the hydrated-glass products. The Yucca Mountain Draft Environmental Assessment (DEA) of December 1984 indicates that: most of the available glass in the proximity of the repository horizon has been already hydrated and authigenic minerals which could form have already done so, zeolites could form from as yet unreacted glass during transport of water exiting from the repository, and the zeolites and other authigenic minerals provide sorptive barriers to radionuclide migration. This document surveys the available literature and concludes that the topic appears more complex than as it is treated in the DEA. It is concluded that an insufficient quantity of raw data exists. This paucity of information does not allow the determination of which authigenic minerals (if any) may form from the alteration of volcanic glass in Yucca Mountain; and consequently, radionuclide retardation leading from this reaction process is undeterminable. Appendix A and B contain a critical review of this publication. 29 refs., 6 tabs.

  16. The behavior of silicon and boron in the surface of corroded nuclear waste glasses : an EFTEM study.

    SciTech Connect

    Buck, E. C.; Smith, K. L.; Blackford, M. G.

    1999-11-23

    Using electron energy-loss filtered transmission electron microscopy (EFTEM), we have observed the formation of silicon-rich zones on the corroded surface of a West Valley (WV6) glass. This layer is approximately 100-200 nm thick and is directly underneath a precipitated smectite clay layer. Under conventional (C)TEM illumination, this layer is invisible; indeed, more commonly used analytical techniques, such as x-ray energy dispersive spectroscopy (EDS), have failed to describe fully the localized changes in the boron and silicon contents across this region. Similar silicon-rich and boron-depleted zones were not found on corroded Savannah River Laboratory (SRL) borosilicate glasses, including SRL-EA and SRL-51, although they possessed similar-looking clay layers. This study demonstrates a new tool for examining the corroded surfaces of materials.

  17. Waste glass weathering

    SciTech Connect

    Bates, J.K.; Buck, E.C.

    1993-12-31

    The weathering of glass is reviewed by examining processes that affect the reaction of commercial, historical, natural, and nuclear waste glass under conditions of contact with humid air and slowly dripping water, which may lead to immersion in nearly static solution. Radionuclide release data from weathered glass under conditions that may exist in an unsaturated environment are presented and compared to release under standard leaching conditions. While the comparison between the release under weathering and leaching conditions is not exact, due to variability of reaction in humid air, evidence is presented of radionuclide release under a variety of conditions. These results suggest that both the amount and form of radionuclide release can be affected by the weathering of glass.

  18. Glass corrosion in natural environments

    NASA Technical Reports Server (NTRS)

    Thorpe, Arthur N.; Barkatt, Aaron

    1992-01-01

    Experiments carried out during the progress period are summarized. Experiments carried out involving glass samples exposed to solutions of Tris have shown the appearance of 'spikes' upon monitoring glass dissolution as a function of time. The periodic 'spikes' observed in Tris-based media were interpreted in terms of cracking due to excessive stress in the surface region of the glass. Studies of the interactions of silicate glasses with metal ions in buffered media were extended to systems containing Al. Caps buffer was used to establish the pH. The procedures used are described and the results are given. Preliminary studies were initiated as to the feasibility of adding a slowly dissolving solid compound of the additive to the glass-water system to maintain a supply of dissolved additive. It appears that several magnesium compounds have a suitable combination of solubility and affinity towards silicate glass surfaces to have a pronounced retarding effect on the extraction of uranium from the glass. These preliminary findings raise the possibility that introducing a magnesium source into geologic repositories for nuclear waste glass in the form of a sparingly soluble Mg-based backfill material may cause a substantial reduction in the extent of long-term glass corrosion. The studies described also provide mechanistic understanding of the roles of various metal solutes in the leachant. Such understanding forms the basis for developing long-term predictions of nuclear waste glass durability under repository conditions. From what is known about natural highly reduced glasses such as tektites, it is clear that iron is dissolved as ferrous iron with little or no ferric iron. The reducing conditions were high enough to cause metallic iron to exsolve out of the glass in the form of submicroscopic spherules. As the nuclear waste glass is much less reduced, a study was initiated on other natural glasses in addition to the nuclear waste glass. Extensive measurements were carried out on these glasses in order to characterize their magnetic properties. Results of these studies are described.

  19. Biodegradation of the french reference nuclear glass SON 68 by Acidithiobacillus thiooxidans : protective effect of the biofilm,U and REE retention

    NASA Astrophysics Data System (ADS)

    Bachelet, M.; Crovisier, J.; Stille, P.; Boutin, R.; Vuilleumier, S.; Geoffroy, V.

    2008-12-01

    Although underground nuclear waste repositories are not expected to be favourable places for microbial activity, one should not exclude localized action of extremophilic bacteria on some materials involved in the storage concept. Among endogenous or accidentally introduced acidophiles, some are susceptible to lead to a locally drastic decreased in pH with potential consequences on materials corrosion. Experiments were performed with Acidithiobacillus thiooxidans on 100-125 ?m french reference nuclear glass SON68 grains in a mineral medium under static conditions during 60 days at 25°C. Growth medium was periodically renewed and analyzed by ICP-AES and ICP-MS spectrometry for both major, traces and ultra-traces elements. Biofilm formation was evidenced by confocal laser microscopy, staining DNA with ethidium bromide and exopolysaccharides with calcofluor white. Biofilm thickness around material grains exceeded 20 ?m under the chosen experimental conditions. It can be noticed that while numerous studies on biofilm formation upon interaction between Acidithiobacillus ferrooxidans and materials can be found in the literature, evidence for biofilm formation is still scarce for the case of the acidophilic bacterium A. thiooxidans. Presence of biofilm is a key parameter for material alteration at the solid/solution interface in biotic systems. Indeed, various constitutive elements of materials trapped in the polyanionic polymer of biofilm may also influence the alteration process. In particular, biofilm may reduce the alteration rate of materials by forming a protective barrier at their surface (Aouad et al., 2008). In this study, glass alteration rates, determined using strontium, molybdenum and caesium as tracers, showed that the biofilm has a protective effect against glass alteration. U and REE are efficiently trapped in the biogenic compartment of the system (exopolysaccharides (EPS) + bacterial cells). Biofilm analysis are in progress to determine whether these elements are in bacterial cells or in the EPS. . Aouad G., Crovisier J.-L., Damidot D., Stille P., Hutchens E., Mutterer J., Meyer J.-M., and Geoffroy V. A. (2008) Interactions between municipal solid waste incinerator bottom ash and bacteria (Pseudomonas aeruginosa). Science of The Total Environment 393(2-3), 385-393.

  20. Origin of cluster spin glass and nuclear Schottky anomaly in Mn50Ni38.5Sn11.5 alloy

    NASA Astrophysics Data System (ADS)

    Ray, Mayukh K.; Bagani, K.; Mukhopadhyay, P. K.; Banerjee, S.

    2015-02-01

    The magnetic ground state of the Mn50Ni38.5Sn11.5 alloy is investigated through dc/ac magnetization and low-temperature (?0.15 \\text{K}) specific-heat (Cp(T)) measurements. The dc and ac magnetization measurements indicate that the system can be identified as a cluster spin glass (CSG) phase in a ferromagnetic (FM) background, and as a conjunction of these two phases an exchange bias effect (EBE) is observed in this system. The presence of coexisting phases is further supported by our Cp(T) measurement. We attribute the existence of the CSG phase to the antiferromagnetic (AFM) interaction arising from the Mn-Mn antisite disorder which further enhances through martensite transformation. The anomalous increase of C p below 0.7 K is due to the nuclear Schottky anomaly arising from the hyperfine splitting of the nuclear levels of Mn atoms. Detailed reasons for the observed behaviours are discussed in the paper.

  1. Simultaneous Nuclear Reaction Analysis of Boron and Phosphorus in Thin Borophosphosilicate Glass Films Using (A,P) Reactions

    SciTech Connect

    Walsh, D.S.; Doyle, B.L.

    1999-06-22

    A method combining ({alpha},p) NRA and ellipsometry has been developed for measuring the Boron and Phosphorus content of borophosphosilicate glass (BPSG) used for interlevel dielectrics in integrated circuits. Yields from the {sup 31}P({alpha},p{sub 0}){sup 34}S (Q = 0.63 MeV) and {sup 10}B({alpha},p{sub 0}) {sup 13}C (Q = 4.06 MeV) reactions are coupled with ellipsometry thickness measurements to calculate the average atomic percent of B and P in the film. Due to the relatively low Q value of the {sup 31}P({alpha},p{sub 0}){sup 34}S reaction and the thickness range of the glass films ({le} 1.2 micrometers) they analyze, fairly high energy alpha particles, and Mylar range foils on the detector are required. Alpha energy, detector angle and range foil thickness were determined by reaction yields and the need to separate the yield peaks of interest from competing ({alpha},p) reactions and backscattered alphas. They have determined that 6.0 MeV incident alphas with a detector angle of 135{degree} and about 100 micrometers of Mylar range foil are optimum for the system. The yield for the {sup 10}B({alpha},p{sub 0}) {sup 13}C reaction is quite constant in the energy range of interest ({approximately} 5.8 to 6 MeV) but the yield for the {sup 31}P({alpha},p{sub 0}){sup 34}S is not. Consequently, a simple conversion from standard BPSG reference samples (independently quantified by ICP mass spectrometry) is adequate to calculate a film's %B content. The %P calculation is more complex, involving a three-dimensional fit of the P yield data and measured film thickness to the film %P content. This fit is based upon yield data from a matrix of standard film samples. The technique is sensitive to 0.1% with an accuracy of {+-}3 to {+-}10% depending on the sample. This measurement method is used routinely at Sandia National Laboratories in support of their fabrication process lines.

  2. Structural studies of mixed glass former 0.35Na2O + 0.65[xB2O3 + (1 - x)P2O5] glasses by Raman and 11B and 31P magic angle spinning nuclear magnetic resonance spectroscopies.

    PubMed

    Christensen, Randilynn; Olson, Garrett; Martin, Steve W

    2013-02-21

    The mixed glass former (MGF) effect (MGFE) is defined as a nonlinear and nonadditive change in the ionic conductivity with changing glass former composition at constant modifier composition. In this study, sodium borophosphate 0.35Na(2)O + 0.65[xB(2)O(3) + (1 - x)P(2)O(5)], 0 ? x ? 1, glasses which have been shown to exhibit a positive MGFE have been prepared and examined using Raman and (11)B and (31)P magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopies. Through examination of the short-range order (SRO) structures found in the ternary glasses, it was determined that the minority glass former, B for 0.1 ? x ? 0.7 and P for 0.7 ? x ? 0.9, is "overmodified" and contains more Na(+) ions than would be expected from simple linear mixing of the binary sodium borate, x = 1, and sodium phosphate, x = 0, glasses, respectively. Changes in the intermediate range order (IRO) structures were suggested by changes in the NMR spectral chemical shifts and Raman spectra wavenumber shifts over the full composition range x in the Raman and MAS NMR spectra. The changes observed in the chemical shifts of (31)P MAS NMR spectra with x are found to be too large to be caused solely by changing sodium modification of the phosphate SRO structural groups, and this indicates that internetwork bonding between phosphorus and boron through bridging oxygens (BOs), P-O-B, must be a major contributor to the IRO structure of these glasses. While not fully developed, a first-order thermodynamic analysis based upon the Gibbs free energies of formation of the various SRO structural units in this system has been developed and can be used to account for the preferential formation of tetrahedral boron groups, B(4), by the reaction of B(3) with P(2) groups to form B(4) and P(3) groups, respectively, where the superscript denotes the number of BOs on these units, in these glasses. This preference for B(4) units appears to be a predominate cause of the changing modifier to glass former ratio with composition x in these ternary MGF glasses and appears to be associated with the large negative value of the Gibbs free energy of formation of this group. PMID:23281937

  3. Consolidated silica glass from nanoparticles

    SciTech Connect

    Mayerhoefer, Thomas G. Shen Zhijian; Leonova, Ekaterina; Eden, Mattias; Kriltz, Antje; Popp, Juergen

    2008-09-15

    A dense silica glass was prepared by consolidating a highly dispersed silicic acid powder (particle size <10 nm) with the Spark Plasma Sintering (SPS) technique. The glass was characterized by ellipsometry, transmission electron microscopy (TEM), infrared reflectance and transmittance spectroscopy, as well as by Raman, UV-Vis-NIR and solid-state nuclear magnetic resonance (NMR) spectroscopy. The prototypic sample showed a transmittance of about 63% compared to silica glass in the UV-Vis spectral range. Based on the results of infrared transmittance spectroscopy this lower transparency is due to the comparably high water content, which is about 40 times higher than that in silica glass. {sup 1}H magic-angle spinning (MAS) NMR confirmed an increase in hydroxyl groups in the sample prepared by SPS relative to that of the conventional SiO{sub 2} reference glass. Aside from the comparably high water content, we conclude from the similarity of the IR-reflectance and the {sup 29}Si MAS NMR spectra of the SPS sample and the corresponding spectra of the conventionally prepared silica glass, that the short- and medium-range order is virtually the same in both materials. Raman spectroscopy, however, suggests that the number of three- and four-membered rings is significantly smaller in the SPS sample compared to the conventionally prepared sample. Based on these results we conclude that it is possible to prepare glasses by compacting amorphous powders by the SPS process. The SPS process may therefore enable the preparation of glasses with compositions inaccessible by conventional methods. - Graphical abstract: We report the preparation of SiO{sub 2} glass by consolidating a highly dispersed silicic acid powder with the Spark Plasma Sintering (SPS) technique. The glass was characterized by ellipsometry, transmission electron microscopy (TEM), infrared reflectance and transmittance spectroscopy, as well as by Raman-, UV-Vis-NIR- and solid-state nuclear magnetic resonance (NMR) spectroscopy.

  4. Glass microspheres

    SciTech Connect

    Day, D.E.; Ehrhardt, G.J.

    1988-12-06

    This patent describes a glass microsphere having a diameter of about 54 micrometers or less and adapted for radiation therapy of a mammal. The glass consists of essentially an yttrium oxide-aluminosilicate glass composition lying substantially within a quadrilateral region of the ternary composition diagram of the yttria-alumina-silica system, the quadrilateral region being defined by its four corners having the following combination of weight proportions of the components: 20% silica, 10% alumina, 70% yttria; 70% silica, 10% alumina, 20% yttria; 70% silica, 20% alumina, 10% yttria; and 20% silica, 45% alumina, 35% yttria, the glass having a chemical durability such that subsequent to irradiation and administration of the microsphere to the mammal, the mircosphere will not release a significant amount of yttrium-90 into the mammal's system.

  5. Tempered glass

    SciTech Connect

    Bunnell, L.R.

    1991-11-01

    This document describes a demonstration for making tempered glass using minimal equipment. The demonstration is intended for a typical student of materials science, at the high school level or above. (JL)

  6. Silicate Glass Corrosion Mechanism revisited

    NASA Astrophysics Data System (ADS)

    Geisler, Thorsten; Lenting, Christoph; Dohmen, Lars

    2015-04-01

    Understanding the mechanism(s) of aqueous corrosion of nuclear waste borosilicate glasses is essential to predict their long-term aqueous durability in a geologic repository. Several observations have been made with compositionally different silicate glasses that cannot be explained by any of the established glass corrosion models. These models are based on diffusion-controlled ion exchange and subsequent structural reorganisation of a leached, hydrated residual glass, leaving behind a so-called gel layer. In fact, the common observation of lamellar to more complex pattern formation observed in experiment and nature, the porous structure of the corrosion layer, an atomically sharp boundary between the corrosion zone and the underlying pristine glass, as well as results of novel isotope tracer and in situ, real time experiments rather support an interface-coupled glass dissolution-silica reprecipitation model. In this model, the congruent dissolution of the glass is coupled in space and time to the precipitation and growth of amorphous silica at an inwardly moving reaction front. We suggest that these coupled processes have to be considered to realistically model the long-term performance of silicate glasses in aqueous environments.

  7. Failure analysis of the lithium battery: A study of the header deposit on the cell top and diffusion within the electrode glass seal using nuclear microanalysis and FFTIR spectroscopy

    NASA Technical Reports Server (NTRS)

    Hassan, Razi A.

    1991-01-01

    The Solid Rocket Booster Range Safety System (SRBRSS) uses a lithium/poly-carbon monofluoride primary battery as a source of electrical power. After cell fabrication and activation, some battery cells have shown self discharge. One possible source of this cell discharge has been suggested to be the formation and growth of a conducting crystallized chemical compound across the glass bead insulator, electrically shorting the glass bead to the casing. This laboratory has begun an analysis of this compound, the glass seal holding the cathode into place, and the cell electrolyte, using Fast Fourier Transform Infrared (FFTIR) Analysis, Rutherford Backscattering Spectroscopy (RBS), and Nuclear Reaction Microanalysis. Preliminary measurements have confirmed the existence of lithium, nitrogen, fluorine, and oxygen on a reddish-brown deposit covering parts of the glass seal holding the positive electrode in place. Cells using Li metal electrodes, have many advantages over conventional primary batteries. One principal disadvantage of using Li batteries on a commercial basis would be the environmental impact of the fluorocarbon material. Another would be the relatively high expense of (CF)n.

  8. DURABLE GLASS FOR THOUSANDS OF YEARS

    SciTech Connect

    Jantzen, C.

    2009-12-04

    The durability of natural glasses on geological time scales and ancient glasses for thousands of years is well documented. The necessity to predict the durability of high level nuclear waste (HLW) glasses on extended time scales has led to various thermodynamic and kinetic approaches. Advances in the measurement of medium range order (MRO) in glasses has led to the understanding that the molecular structure of a glass, and thus the glass composition, controls the glass durability by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. During the early stages of glass dissolution, a 'gel' layer resembling a membrane forms through which ions exchange between the glass and the leachant. The hydrated gel layer exhibits acid/base properties which are manifested as the pH dependence of the thickness and nature of the gel layer. The gel layer ages into clay or zeolite minerals by Ostwald ripening. Zeolite mineral assemblages (higher pH and Al{sup 3+} rich glasses) may cause the dissolution rate to increase which is undesirable for long-term performance of glass in the environment. Thermodynamic and structural approaches to the prediction of glass durability are compared versus Ostwald ripening.

  9. Alice through Looking Glass after Looking Glass

    E-print Network

    Goodman, Roe

    Alice through Looking Glass after Looking Glass: The Mathematics of Mirrors and Kaleidoscopes Roe Looking Glass After Looking Glass: Alice finds in one corner of her chamber a cone-shaped arrangement in the corner could be arranged so that she could have other trips through the looking glasses and still get

  10. Durability of Silicate Glasses: An Historical Approach

    SciTech Connect

    Farges, Francois; Etcheverry, Marie-Pierre; Haddi, Amine; Trocellier, Patrick; Curti, Enzo; Brown, Gordon E., Jr.; /SLAC, SSRL

    2007-01-02

    We present a short review of current theories of glass weathering, including glass dissolution, and hydrolysis of nuclear waste glasses, and leaching of historical glasses from an XAFS perspective. The results of various laboratory leaching experiments at different timescales (30 days to 12 years) are compared with results for historical glasses that were weathered by atmospheric gases and soil waters over 500 to 3000 years. Good agreement is found between laboratory experiments and slowly leached historical glasses, with a strong enrichment of metals at the water/gel interface. Depending on the nature of the transition elements originally dissolved in the melt, increasing elemental distributions are expected to increase with time for a given glass durability context.

  11. Glass Ceramic Formulation Data Package

    SciTech Connect

    Crum, Jarrod V.; Rodriguez, Carmen P.; McCloy, John S.; Vienna, John D.; Chung, Chul-Woo

    2012-06-17

    A glass ceramic waste form is being developed for treatment of secondary waste streams generated by aqueous reprocessing of commercial used nuclear fuel (Crum et al. 2012b). The waste stream contains a mixture of transition metals, alkali, alkaline earths, and lanthanides, several of which exceed the solubility limits of a single phase borosilicate glass (Crum et al. 2009; Caurant et al. 2007). A multi-phase glass ceramic waste form allows incorporation of insoluble components of the waste by designed crystallization into durable heat tolerant phases. The glass ceramic formulation and processing targets the formation of the following three stable crystalline phases: (1) powellite (XMoO4) where X can be (Ca, Sr, Ba, and/or Ln), (2) oxyapatite Yx,Z(10-x)Si6O26 where Y is alkaline earth, Z is Ln, and (3) lanthanide borosilicate (Ln5BSi2O13). These three phases incorporate the waste components that are above the solubility limit of a single-phase borosilicate glass. The glass ceramic is designed to be a single phase melt, just like a borosilicate glass, and then crystallize upon slow cooling to form the targeted phases. The slow cooling schedule is based on the centerline cooling profile of a 2 foot diameter canister such as the Hanford High-Level Waste canister. Up to this point, crucible testing has been used for glass ceramic development, with cold crucible induction melter (CCIM) targeted as the ultimate processing technology for the waste form. Idaho National Laboratory (INL) will conduct a scaled CCIM test in FY2012 with a glass ceramic to demonstrate the processing behavior. This Data Package documents the laboratory studies of the glass ceramic composition to support the CCIM test. Pacific Northwest National Laboratory (PNNL) measured melt viscosity, electrical conductivity, and crystallization behavior upon cooling to identify a processing window (temperature range) for melter operation and cooling profiles necessary to crystallize the targeted phases in the waste form.

  12. Prediction of glass durability as a function of environmental conditions

    SciTech Connect

    Jantzen, C.M.

    1988-01-01

    A thermodynamic model of glass durability is applied to natural, ancient, and nuclear waste glasses. The durabilities of over 150 different natural and man-made glasses, including actual ancient Roman and Islamic glasses (Jalame ca. 350 AD, Nishapur 10-11th century AD and Gorgon 9-11th century AD), are compared. Glass durability is a function of the thermodynamic hydration free energy, ..delta..G/sub hyd/, which can be calculated from glass composition and solution pH. The durability of the most durable nuclear waste glasses examined was /approximately/10/sup 6/ years. The least durable waste glass formulations were comparable in durability to the most durable simulated medieval window glasses of /approximately/10/sup 3/ years. In this manner, the durability of nuclear waste glasses has been interpolated to be /approximately/10/sup 6/ years and no less than 10/sup 3/ years. Hydration thermodynamics have been shown to be applicable to the dissolution of glass in various natural environments. Groundwater-glass interactions relative to geologic disposal of nuclear waste, hydration rind dating of obsidians, andor other archeological studies can be modeled, e.g., the relative durabilities of six simulated medieval window glasses have been correctly predicted for both laboratory (one month) and burial (5 years) experiments. Effects of solution pH on glass dissolution has been determined experimentally for the 150 different glasses and can be predicted theoretically by hydration thermodynamics. The effects of solution redox on dissolution of glass matrix elements such as SI and B have shown to be minimal. The combined effects of solution pH and Eh have been described and unified by construction of thermodynamically calculated Pourbaix (pH-Eh) diagrams for glass dissolution. The Pourbaix diagrams have been quantified to describe glass dissolution as a function of environmental conditions by use of the data derived from hydration thermodynamics. 56 refs., 7 figs.

  13. Pinhole Glasses

    NASA Astrophysics Data System (ADS)

    Colicchia, Giuseppe; Hopf, Martin; Wiesner, Hartmut; Zollman, Dean

    2008-01-01

    Eye aberrations are commonly corrected by lenses that restore vision by altering rays before they pass through the cornea. Some modern promoters claim that pinhole glasses are better than conventional lenses in correcting all kinds of refractive defects such as myopia (nearsighted), hyperopia (farsighted), astigmatisms, and presbyopia. Do pinhole glasses really give better vision? Some ways to use this question for motivation in teaching optics have been discussed. For this column we include a series of experiments that students can complete using a model of the eye and demonstrate issues related to pinhole vision correction.

  14. Prediction of glass durability as a function of glass composition and test conditions: Thermodynamics and kinetics

    SciTech Connect

    Jantzen, C.M.

    1988-01-01

    The long-term durability of nuclear waste glasses can be predicted by comparing their performance to natural and ancient glasses. Glass durability is a function of the kinetic and thermodynamic stability of glass in solution. The relationship between the kinetic and thermodynamic aspects of glass durability can be understood when the relative contributions of glass composition and imposed test conditions are delineated. Glass durability has been shown to be a function of the thermodynamic hydration free energy which can be calculated from the glass composition. Hydration thermodynamics also furnishes a quantitative frame of reference to understand how various test parameters affect glass durability. Linear relationships have been determined between the logarithmic extent of hydration and the calculated hydration free energy for several different test geometries. Different test conditions result in different kinetic reactivity parameters such as the exposed glass surface area (SA), the leachant solution volume (V), and the length of time that the glass is in the leachant (t). Leachate concentrations are known to be a function of the kinetic test parameter (SAV)t. The relative durabilities of glasses, including pure silica, obsidians, nuclear waste glasses, medieval window glasses, and frit glasses define a plane in three dimensional ..delta..G/sub hyd/-concentration-(SAV)t space. At constant kinetic conditions, e.g., test geometry and test duration, the three dimensional plane is intersected at constant (SAV)t and the ..delta..G/sub hyd/-concentration plots have similar slopes. The slope represents the natural logarithm of the theoretical slope, (12.303 RT), for the rate of glass dissolution. 53 refs., 4 figs.

  15. Surface reactions of natural glasses

    SciTech Connect

    White, A.F.

    1986-12-31

    Reactions at natural glass surfaces are important in studies involving nuclear waste transport due to chemical control on ground water in host rocks such as basalt and tuff, to potential diffusion into natural hydrated glass surfaces and as natural analogs for waste glass stability. Dissolution kinetics can be described by linear surface reaction coupled with cation interdiffusion with resulting rates similar to those of synthetic silicate glasses. Rates of Cs diffusion into hydrated obsidian surfaces between 25{sup 0} and 75{sup 0}C were determined by XPS depth profiles and loss rates from aqueous solutions. Calculated diffusion coefficients were ten others of magnitude more rapid than predicted from an Arrhenius extrapolation of high temperature tracer diffusion data due to surface hydration reactions.

  16. Pinhole Glasses

    ERIC Educational Resources Information Center

    Colicchia, Giuseppe; Hopf, Martin; Wiesner, Hartmut; Zollman, Dean

    2008-01-01

    Eye aberrations are commonly corrected by lenses that restore vision by altering rays before they pass through the cornea. Some modern promoters claim that pinhole glasses are better than conventional lenses in correcting all kinds of refractive defects such as myopia (nearsighted), hyperopia (farsighted), astigmatisms, and presbyopia. Do pinhole…

  17. The incorporation of P, S, Cr, F, Cl, I, Mn, Ti, U, and Bi into simulated nuclear waste glasses: Literature study

    SciTech Connect

    Langowski, M.H.

    1996-02-01

    Waste currently stored on the Hanford Reservation in underground tanks will be into High Level Waste (HLW) and Low Level Waste (LLW). The HLW melter will high-level and transuranic wastes to a vitrified form for disposal in a geological repository. The LLW melter will vitrify the low-level waste which is mainly a sodium solution. Characterization of the tank wastes is still in progress, and the pretreatment processes are still under development Apart from tank-to-tank variations, the feed delivered to the HLW melter will be subject to process control variability which consists of blending and pretreating the waste. The challenge is then to develop glass formulation models which can produce durable and processable glass compositions for all potential vitrification feed compositions and processing conditions. The work under HLW glass formulation is to study and model glass and melt pro functions of glass composition and temperature. The properties of interest include viscosity, electrical conductivity, liquidus temperature, crystallization, immiscibility durability. It is these properties that determine the glass processability and ac waste glass. Apart from composition, some properties, such as viscosity are affected by temperature. The processing temperature may vary from 1050{degrees}C to 1550{degrees}C dependent upon the melter type. The glass will also experience a temperature profile upon cooling. The purpose of this letter report is to assess the expected vitrification feed compositions for critical components with the greatest potential impact on waste loading for double shell tank (DST) and single shell tank (SST) wastes. The basis for critical component selection is identified along with the planned approach for evaluation. The proposed experimental work is a crucial part of model development and verification.

  18. Temperature effects on waste glass performance

    SciTech Connect

    Mazer, J.J.

    1991-02-01

    The temperature dependence of glass durability, particularly that of nuclear waste glasses, is assessed by reviewing past studies. The reaction mechanism for glass dissolution in water is complex and involves multiple simultaneous reaction proceeded, including molecular water diffusion, ion exchange, surface reaction, and precipitation. These processes can change in relative importance or dominance with time or changes in temperature. The temperature dependence of each reaction process has been shown to follow an Arrhenius relationship in studies where the reaction process has been isolated, but the overall temperature dependence for nuclear waste glass reaction mechanisms is less well understood, Nuclear waste glass studies have often neglected to identify and characterize the reaction mechanism because of difficulties in performing microanalyses; thus, it is unclear if such results can be extrapolated to other temperatures or reaction times. Recent developments in analytical capabilities suggest that investigations of nuclear waste glass reactions with water can lead to better understandings of their reaction mechanisms and their temperature dependences. Until a better understanding of glass reaction mechanisms is available, caution should be exercised in using temperature as an accelerating parameter. 76 refs., 1 tab.

  19. Structure of rhenium-containing sodium borosilicate glass

    SciTech Connect

    Goel, Ashutosh; McCloy, John S.; Windisch, Charles F.; Riley, Brian J.; Schweiger, Michael J.; Rodriguez, Carmen P.; Ferreira, Jose M.

    2013-03-01

    A series of sodium borosilicate glasses were synthesized with increasing fractions of KReO4 or Re2O7, to 10000 ppm (1 mass%) target Re in glass, to assess the effects of large concentrations of rhenium on glass structure and to estimate the solubility of technetium, a radioactive component in typical low active waste nuclear waste glasses. Magic angle spinning nuclear magnetic resonance (MAS-NMR), Fourier transform infrared (FTIR) spectroscopy, and Raman spectroscopy were performed to characterize the glasses as a function of Re source additions. In general, silicon was found coordinated in a mixture of Q2 and Q3 structural units, while Al was 4-coordinated and B was largely 3-coordinate and partially 4-coordinated. The rhenium source did not appear to have significant effects on the glass structure. Thus, at the up to the concentrations that remain in dissolved in glass, ~3000 ppm Re by mass maximum. , the Re appeared to be neither a glass-former nor a strong glass modifier., Rhenium likely exists in isolated ReO4- anions in the interstices of the glass network, as evidenced by the polarized Raman spectrum of the Re glass in the absence of sulfate. Analogous to SO42-¬ in similar glasses, ReO4- is likely a network modifier and forms alkali salt phases on the surface and in the bulk glass above solubility.

  20. Glass viscosity calculation based on a global statistical modelling approach

    SciTech Connect

    Fluegel, Alex

    2007-02-01

    A global statistical glass viscosity model was developed for predicting the complete viscosity curve, based on more than 2200 composition-property data of silicate glasses from the scientific literature, including soda-lime-silica container and float glasses, TV panel glasses, borosilicate fiber wool and E type glasses, low expansion borosilicate glasses, glasses for nuclear waste vitrification, lead crystal glasses, binary alkali silicates, and various further compositions from over half a century. It is shown that within a measurement series from a specific laboratory the reported viscosity values are often over-estimated at higher temperatures due to alkali and boron oxide evaporation during the measurement and glass preparation, including data by Lakatos et al. (1972) and the recently published High temperature glass melt property database for process modeling by Seward et al. (2005). Similarly, in the glass transition range many experimental data of borosilicate glasses are reported too high due to phase separation effects. The developed global model corrects those errors. The model standard error was 9-17°C, with R^2 = 0.985-0.989. The prediction 95% confidence interval for glass in mass production largely depends on the glass composition of interest, the composition uncertainty, and the viscosity level. New insights in the mixed-alkali effect are provided.

  1. Impact Strength of Glass and Glass Ceramic

    NASA Astrophysics Data System (ADS)

    Bless, S.; Tolman, J.

    2009-12-01

    Strength of glass and glass ceramic was measured with a bar impact technique. High-speed movies show regions of tensile and compressive failure. The borosilicate glass had a compressive strength of at least 2.2 GPa, and the glass ceramic at least 4 GPa. However, the BSG was much stronger in tension than GC. In ballistic tests, the BSG was the superior armor.

  2. IMPACT STRENGTH OF GLASS AND GLASS CERAMIC

    SciTech Connect

    Bless, S.; Tolman, J.

    2009-12-28

    Strength of glass and glass ceramic was measured with a bar impact technique. High-speed movies show regions of tensile and compressive failure. The borosilicate glass had a compressive strength of at least 2.2 GPa, and the glass ceramic at least 4 GPa. However, the BSG was much stronger in tension than GC. In ballistic tests, the BSG was the superior armor.

  3. Gaseous Sulfate Solubility in Glass: Experimental Method

    SciTech Connect

    Bliss, Mary

    2013-11-30

    Sulfate solubility in glass is a key parameter in many commercial glasses and nuclear waste glasses. This report summarizes key publications specific to sulfate solubility experimental methods and the underlying physical chemistry calculations. The published methods and experimental data are used to verify the calculations in this report and are expanded to a range of current technical interest. The calculations and experimental methods described in this report will guide several experiments on sulfate solubility and saturation for the Hanford Waste Treatment Plant Enhanced Waste Glass Models effort. There are several tables of sulfate gas equilibrium values at high temperature to guide experimental gas mixing and to achieve desired SO3 levels. This report also describes the necessary equipment and best practices to perform sulfate saturation experiments for molten glasses. Results and findings will be published when experimental work is finished and this report is validated from the data obtained.

  4. A simple method for tuning the glass transition process in inorganic phosphate glasses

    NASA Astrophysics Data System (ADS)

    Fulchiron, René; Belyamani, Imane; Otaigbe, Joshua U.; Bounor-Legaré, Véronique

    2015-02-01

    The physical modification of glass transition temperature (Tg) and properties of materials via blending is a common practice in industry and academia and has a large economic advantage. In this context, simple production of hitherto unattainable new inorganic glass blends from already existing glass compositions via blending raises much hope with the potential to provide new glasses with new and improved properties, that cannot be achieved with classical glass synthesis, for a plethora of applications such as computers screens, glass-to-metal seals, and storage materials for nuclear wastes. Here, we demonstrate that blends of the specific glass compositions studied are miscible in all proportions, an unreported phenomenon in hard condensed matter like glass. Interestingly, excellent agreement was found between the obtained data and calculated Tgs from theoretical equations (Supplementary information) for predicting the composition dependence of Tg for miscible blends with weak but significant specific interactions between the blend components. That this blending method is at present not applied to inorganic glasses reflects the fact that water and chemically resistant phosphate glasses with relatively low Tgs have become available only recently.

  5. A simple method for tuning the glass transition process in inorganic phosphate glasses.

    PubMed

    Fulchiron, René; Belyamani, Imane; Otaigbe, Joshua U; Bounor-Legaré, Véronique

    2015-01-01

    The physical modification of glass transition temperature (T(g)) and properties of materials via blending is a common practice in industry and academia and has a large economic advantage. In this context, simple production of hitherto unattainable new inorganic glass blends from already existing glass compositions via blending raises much hope with the potential to provide new glasses with new and improved properties, that cannot be achieved with classical glass synthesis, for a plethora of applications such as computers screens, glass-to-metal seals, and storage materials for nuclear wastes. Here, we demonstrate that blends of the specific glass compositions studied are miscible in all proportions, an unreported phenomenon in hard condensed matter like glass. Interestingly, excellent agreement was found between the obtained data and calculated Tgs from theoretical equations (Supplementary information) for predicting the composition dependence of T(g) for miscible blends with weak but significant specific interactions between the blend components. That this blending method is at present not applied to inorganic glasses reflects the fact that water and chemically resistant phosphate glasses with relatively low T(g)s have become available only recently. PMID:25666949

  6. A simple method for tuning the glass transition process in inorganic phosphate glasses

    PubMed Central

    Fulchiron, René; Belyamani, Imane; Otaigbe, Joshua U.; Bounor-Legaré, Véronique

    2015-01-01

    The physical modification of glass transition temperature (Tg) and properties of materials via blending is a common practice in industry and academia and has a large economic advantage. In this context, simple production of hitherto unattainable new inorganic glass blends from already existing glass compositions via blending raises much hope with the potential to provide new glasses with new and improved properties, that cannot be achieved with classical glass synthesis, for a plethora of applications such as computers screens, glass-to-metal seals, and storage materials for nuclear wastes. Here, we demonstrate that blends of the specific glass compositions studied are miscible in all proportions, an unreported phenomenon in hard condensed matter like glass. Interestingly, excellent agreement was found between the obtained data and calculated Tgs from theoretical equations (Supplementary information) for predicting the composition dependence of Tg for miscible blends with weak but significant specific interactions between the blend components. That this blending method is at present not applied to inorganic glasses reflects the fact that water and chemically resistant phosphate glasses with relatively low Tgs have become available only recently. PMID:25666949

  7. Comparison of mechanical properties of glass-bonded sodalite and borosilicate glass high-level waste forms

    SciTech Connect

    O'Holleran, T. P.; DiSanto, T.; Johnson, S. G.; Goff, K. M.

    2000-05-09

    Argonne National Laboratory has developed a glass-bonded sodalite waste form to immobilize the salt waste stream from electrometallurgical treatment of spent nuclear fuel. The waste form consists of 75 vol.% crystalline sodalite and 25 vol.% glass. Microindentation fracture toughness measurements were performed on this material and borosilicate glass from the Defense Waste Processing Facility using a Vickers indenter. Palmqvist cracking was confined for the glass-bonded sodalite waste form, while median-radial cracking occurred in the borosilicate glass. The elastic modulus was measured by an acoustic technique. Fracture toughness, microhardness, and elastic modulus values are reported for both waste forms.

  8. NEWS & VIEWS Glass dynamics

    E-print Network

    Weeks, Eric R.

    NEWS & VIEWS Glass dynamics Diverging views on glass transition Gregory B. mc.mckenna@ttu.edu T he glass transition is one of the most intriguing phenomena in the world of soft condensed matter. Despite decades of study, many aspects of the behaviour of glass-forming liquids remain elusive

  9. Inverted glass harp

    NASA Astrophysics Data System (ADS)

    Quinn, Daniel B.; Rosenberg, Brian J.

    2015-08-01

    We present an analytical treatment of the acoustics of liquid-filled wine glasses, or "glass harps." The solution is generalized such that under certain assumptions it reduces to previous glass harp models, but also leads to a proposed musical instrument, the "inverted glass harp," in which an empty glass is submerged in a liquid-filled basin. The versatility of the solution demonstrates that all glass harps are governed by a family of solutions to Laplace's equation around a vibrating disk. Tonal analyses of recordings for a sample glass are offered as confirmation of the scaling predictions.

  10. Glass-silicon column

    DOEpatents

    Yu, Conrad M.

    2003-12-30

    A glass-silicon column that can operate in temperature variations between room temperature and about 450.degree. C. The glass-silicon column includes large area glass, such as a thin Corning 7740 boron-silicate glass bonded to a silicon wafer, with an electrode embedded in or mounted on glass of the column, and with a self alignment silicon post/glass hole structure. The glass/silicon components are bonded, for example be anodic bonding. In one embodiment, the column includes two outer layers of silicon each bonded to an inner layer of glass, with an electrode imbedded between the layers of glass, and with at least one self alignment hole and post arrangement. The electrode functions as a column heater, and one glass/silicon component is provided with a number of flow channels adjacent the bonded surfaces.

  11. DEVELOPMENT OF GLASS MATRICES FOR HLW RADIOACTIVE WASTES

    SciTech Connect

    Jantzen, C.

    2010-03-18

    Vitrification is currently the most widely used technology for the treatment of high level radioactive wastes (HLW) throughout the world. Most of the nations that have generated HLW are immobilizing in either borosilicate glass or phosphate glass. One of the primary reasons that glass has become the most widely used immobilization media is the relative simplicity of the vitrification process, e.g. melt waste plus glass forming frit additives and cast. A second reason that glass has become widely used for HLW is that the short range order (SRO) and medium range order (MRO) found in glass atomistically bonds the radionuclides and governs the melt properties such as viscosity, resistivity, sulphate solubility. The molecular structure of glass controls contaminant/radionuclide release by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. The molecular structure is flexible and hence accounts for the flexibility of glass formulations to waste variability. Nuclear waste glasses melt between 1050-1150 C which minimizes the volatility of radioactive components such as Tc{sup 99}, Cs{sup 137}, and I{sup 129}. Nuclear waste glasses have good long term stability including irradiation resistance. Process control models based on the molecular structure of glass have been mechanistically derived and have been demonstrated to be accurate enough to control the world's largest HLW Joule heated ceramic melter in the US since 1996 at 95% confidence.

  12. Surface layer effects on waste glass corrosion

    SciTech Connect

    Feng, X.

    1993-12-31

    Water contact subjects waste glass to chemical attack that results in the formation of surface alteration layers. Two principal hypotheses have been advanced concerning the effect of surface alteration layers on continued glass corrosion: (1) they act as a mass transport barrier and (2) they influence the chemical affinity of the glass reaction. In general, transport barrier effects have been found to be less important than affinity effects in the corrosion of most high-level nuclear waste glasses. However, they can be important under some circumstances, for example, in a very alkaline solution, in leachants containing Mg ions, or under conditions where the matrix dissolution rate is very low. The latter suggests that physical barrier effect may affect the long-term glass dissolution rate. Surface layers influence glass reaction affinity through the effects of the altered glass and secondary phases on the solution chemistry. The reaction affinity may be controlled by various precipitates and crystalline phases, amorphous silica phases, gel layer, or all the components of the glass. The surface alteration layers influence radionuclide release mainly through colloid formation, crystalline phase incorporation, and gel layer retention. This paper reviews current understanding and uncertainties.

  13. Compositional Models of Glass/Melt Properties and their Use for Glass Formulation

    SciTech Connect

    Vienna, John D.; USA, Richland Washington

    2014-12-18

    Nuclear waste glasses must simultaneously meet a number of criteria related to their processability, product quality, and cost factors. The properties that must be controlled in glass formulation and waste vitrification plant operation tend to vary smoothly with composition allowing for glass property-composition models to be developed and used. Models have been fit to the key glass properties. The properties are transformed so that simple functions of composition (e.g., linear, polynomial, or component ratios) can be used as model forms. The model forms are fit to experimental data designed statistically to efficiently cover the composition space of interest. Examples of these models are found in literature. The glass property-composition models, their uncertainty definitions, property constraints, and optimality criteria are combined to formulate optimal glass compositions, control composition in vitrification plants, and to qualify waste glasses for disposal. An overview of current glass property-composition modeling techniques is summarized in this paper along with an example of how those models are applied to glass formulation and product qualification at the planned Hanford high-level waste vitrification plant.

  14. Compositional Models of Glass/Melt Properties and their Use for Glass Formulation

    DOE PAGESBeta

    Vienna, John D.; USA, Richland Washington

    2014-12-18

    Nuclear waste glasses must simultaneously meet a number of criteria related to their processability, product quality, and cost factors. The properties that must be controlled in glass formulation and waste vitrification plant operation tend to vary smoothly with composition allowing for glass property-composition models to be developed and used. Models have been fit to the key glass properties. The properties are transformed so that simple functions of composition (e.g., linear, polynomial, or component ratios) can be used as model forms. The model forms are fit to experimental data designed statistically to efficiently cover the composition space of interest. Examples ofmore »these models are found in literature. The glass property-composition models, their uncertainty definitions, property constraints, and optimality criteria are combined to formulate optimal glass compositions, control composition in vitrification plants, and to qualify waste glasses for disposal. An overview of current glass property-composition modeling techniques is summarized in this paper along with an example of how those models are applied to glass formulation and product qualification at the planned Hanford high-level waste vitrification plant.« less

  15. Picture Wall (Glass Structures)

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Photo shows a subway station in Toronto, Ontario, which is entirely glass-enclosed. The all-glass structure was made possible by a unique glazing concept developed by PPG Industries, Pittsburgh, Pennsylvania, one of the largest U.S. manufacturers of flat glass. In the TVS glazing system, transparent glass "fins" replace conventional vertical support members used to provide support for wind load resistance. For stiffening, silicone sealant bonds the fins to adjacent glass panels. At its glass research center near Pittsburgh, PPG Industries uses the NASTRAN computer program to analyze the stability of enclosures made entirely of glass. The company also uses NASTRAN to simulate stresses on large containers of molten glass and to analyze stress effects of solar heating on flat glass.

  16. Hyperpolarized cesium ions doped in a glass material

    NASA Astrophysics Data System (ADS)

    Ishikawa, Kiyoshi

    2014-12-01

    Hyperpolarized (HP) 133 Cs nuclear magnetic resonance signals were measured from borosilicate glass cell walls during optical pumping of cesium vapor at high magnetic field (9.4 T). Significant signal enhancements were observed when additional heating of the cell wall was provided by intense but non-resonant laser irradiation, with integrated HP 133 Cs NMR signals and line widths varying as a function of heating laser power (and hence glass temperature). Given that virtually no Cs ions would originally be present in the glass, absorbed HP Cs atoms rarely met thermally-polarized Cs ions already at the surface; thus, spin-exchange via nuclear dipole interaction cannot be the primary mechanism for injecting spin polarization into the glass. Instead, it is concluded that the absorption and transport of HP atoms into the glass material itself is the dominant mechanism of nuclear spin injection at high temperatures-the first reported experimental demonstration of such a mechanism.

  17. Laboratory work in support of West Valley glass development

    SciTech Connect

    Bunnell, L.R.

    1988-05-01

    Over the past six years, Pacific Northwest Laboratory (PNL) has conducted several studies in support of waste glass composition development and testing of glass compositions suitable for immobilizing the nuclear wastes stored at West Valley, New York. As a result of pilot-scale testing conducted by PNL, the glass composition was changed from that originally recommended in response to changes in the waste stream, and several processing-related problems were discovered. These problems were solved, or sufficiently addressed to determine their likely effect on the glass melting operations to be conducted at West Valley. This report describes the development of the waste glass composition, WV-205, and discusses solutions to processing problems such as foaming and insoluble sludges, as well as other issues such as effects of feed variations on processing of the resulting glass. An evaluation of the WV-205 glass from a repository perspective is included in the appendix to this report.

  18. GlassForm

    Energy Science and Technology Software Center (ESTSC)

    2011-09-16

    GlassForm is a software tool for generating preliminary waste glass formulas for a given waste stream. The software is useful because it reduces the number of verification melts required to develop a suitable additive composition. The software includes property models that calculate glass properties of interest from the chemical composition of the waste glass. The software includes property models for glass viscosity, electrical conductivity, glass transition temperature, and leach resistance as measured by the 7-daymore »product consistency test (PCT).« less

  19. 6. Looking glass aircraft in the project looking glass historic ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Looking glass aircraft in the project looking glass historic district. View to north. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Avenue between Comstat Drive & Nightwatch Avenue, Offutt Air Force Base, Bellevue, Sarpy County, NE

  20. Oxynitride glass fibers

    NASA Technical Reports Server (NTRS)

    Patel, Parimal J.; Messier, Donald R.; Rich, R. E.

    1991-01-01

    Research at the Army Materials Technology Laboratory (AMTL) and elsewhere has shown that many glass properties including elastic modulus, hardness, and corrosion resistance are improved markedly by the substitution of nitrogen for oxygen in the glass structure. Oxynitride glasses, therefore, offer exciting opportunities for making high modulus, high strength fibers. Processes for making oxynitride glasses and fibers of glass compositions similar to commercial oxide glasses, but with considerable enhanced properties, are discussed. We have made glasses with elastic moduli as high as 140 GPa and fibers with moduli of 120 GPa and tensile strengths up to 2900 MPa. AMTL holds a U.S. patent on oxynitride glass fibers, and this presentation discusses a unique process for drawing small diameter oxynitride glass fibers at high drawing rates. Fibers are drawn through a nozzle from molten glass in a molybdenum crucible at 1550 C. The crucible is situated in a furnace chamber in flowing nitrogen, and the fiber is wound in air outside of the chamber, making the process straightforward and commercially feasible. Strengths were considerably improved by improving glass quality to minimize internal defects. Though the fiber strengths were comparable with oxide fibers, work is currently in progress to further improve the elastic modulus and strength of fibers. The high elastic modulus of oxynitride glasses indicate their potential for making fibers with tensile strengths surpassing any oxide glass fibers, and we hope to realize that potential in the near future.

  1. Retention of Halogens in Waste Glass

    SciTech Connect

    Hrma, Pavel R.

    2010-05-01

    In spite of their potential roles as melting rate accelerators and foam breakers, halogens are generally viewed as troublesome components for glass processing. Of five halogens, F, Cl, Br, I, and At, all but At may occur in nuclear waste. A nuclear waste feed may contain up to 10 g of F, 4 g of Cl, and ?100 mg of Br and I per kg of glass. The main concern is halogen volatility, producing hazardous fumes and particulates, and the radioactive iodine 129 isotope of 1.7x10^7-year half life. Because F and Cl are soluble in oxide glasses and tend to precipitate on cooling, they can be retained in the waste glass in the form of dissolved constituents or as dispersed crystalline inclusions. This report compiles known halogen-retention data in both high-level waste (HLW) and low-activity waste (LAW) glasses. Because of its radioactivity, the main focus is on I. Available data on F and Cl were compiled for comparison. Though Br is present in nuclear wastes, it is usually ignored; no data on Br retention were found.

  2. WASTE GLASS MELTER PROCESS MONITORING WITH MILLIMETER WAVES

    EPA Science Inventory

    Millimeter-wave technologies can provide novel and reliable online monitoring capability for many important parameters inside nuclear waste glass melters, including temperature, emissivity, density, and viscosity. The physical and analytical basis for millimeter-wave monitoring o...

  3. Critical review of glass performance modeling

    SciTech Connect

    Bourcier, W.L.

    1994-07-01

    Borosilicate glass is to be used for permanent disposal of high-level nuclear waste in a geologic repository. Mechanistic chemical models are used to predict the rate at which radionuclides will be released from the glass under repository conditions. The most successful and useful of these models link reaction path geochemical modeling programs with a glass dissolution rate law that is consistent with transition state theory. These models have been used to simulate several types of short-term laboratory tests of glass dissolution and to predict the long-term performance of the glass in a repository. Although mechanistically based, the current models are limited by a lack of unambiguous experimental support for some of their assumptions. The most severe problem of this type is the lack of an existing validated mechanism that controls long-term glass dissolution rates. Current models can be improved by performing carefully designed experiments and using the experimental results to validate the rate-controlling mechanisms implicit in the models. These models should be supported with long-term experiments to be used for model validation. The mechanistic basis of the models should be explored by using modern molecular simulations such as molecular orbital and molecular dynamics to investigate both the glass structure and its dissolution process.

  4. FOAM GLASS INSULATION FROM WASTE GLASS

    EPA Science Inventory

    Waste glass has proven to be effective for the production of foam glass insulation both in the bulk or rigid board form and pellet form. Problems inherent with the use of water, carbon black and calcium carbonate as the foaming agents, have been identified and many have been solv...

  5. Weakly supervised glasses removal

    NASA Astrophysics Data System (ADS)

    Wang, Zhicheng; Zhou, Yisu; Wen, Lijie

    2015-03-01

    Glasses removal is an important task on face recognition, in this paper, we provide a weakly supervised method to remove eyeglasses from an input face image automatically. We choose sparse coding as face reconstruction method, and optical flow to find exact shape of glasses. We combine the two processes iteratively to remove glasses more accurately. The experimental results reveal that our method works much better than these algorithms alone, and it can remove various glasses to obtain natural looking glassless facial images.

  6. Technique for Machining Glass

    NASA Technical Reports Server (NTRS)

    Rice, S. H.

    1982-01-01

    Process for machining glass with conventional carbide tools requires a small quantity of a lubricant for aluminum applied to area of glass to be machined. A carbide tool is then placed against workpiece with light pressure. Tool is raised periodically to clear work of glass dust and particles. Additional lubricant is applied as it is displaced.

  7. Glass in Class

    ERIC Educational Resources Information Center

    Greaves, Neville

    2005-01-01

    Glass is reviewed from fabrication to application, laying emphasis on the wide-ranging physics involved. This begins with liquids and solids and the way in which glasses are defined and can be demonstrated in the classroom. At the atomic level the regular structure of crystals and their irregular counterparts in glasses are explained through…

  8. High-Temperature Studies of Glass Dissolution Rates Close to Saturation

    SciTech Connect

    Zavarin, M; Roberts, S; Zhao, P; Williams, R; Rose, T; Rainer, A; Pawloski, G

    2004-06-14

    Most long-lived radionuclides associated with an underground nuclear test are incorporated into a melt glass and are released by glass dissolution to become part of the hydrologic source term (HST) (Pawloski et al., 2001). Although the rates of rhyolite glass dissolution are well known under conditions where the fluid is far from saturation with respect to glass, the rates are not well known under conditions where the fluid approaches saturation. These rates are commonly much lower than the far-fromsaturation rates, often by a factor greater than 100. In recent HST simulations (Pawloski et al., 2001; Pawloski et al., 2000; Tompson et al., 1999), we conservatively estimated steady-state release rates based on a far-from-saturation fluid conditions. In recent CHESHIRE near-field simulations (Pawloski et al., 2001), it was predicted that {approx}30% of the nuclear melt glass dissolved over 1000 years. Although the ''far-from-saturation rate'' approach provides a conservative estimate of glass dissolution, it may greatly overestimate the rates of melt glass dissolution. At CHESHIRE, less conservative estimates suggest that only {approx}1% of the nuclear melt glass will dissolve in 1000 years. Lower glass dissolution rates result in lower radionuclide release rates from nuclear melt glass. The following report documents glass dissolution experiments performed to measure glass dissolution rates close to saturation.

  9. Nanocrystalline glass ceramics: Structural, physical and optical properties

    NASA Astrophysics Data System (ADS)

    Singh, Satwinder; Singh, K.

    2015-02-01

    Four different transition metals contained nanocrystalline glass ceramics are synthesized by melting and quenching technique. The transition metal oxides play as former, modifier or both the roles depending on their oxidation states, field strength and covalent characteristics. The optical band gaps are observed in the range of 3.2-5.5 eV. The presence of nano-crystalline phases dominates the optical band gap. The softening temperature (Ts) is mainly affected by the residual glass in glass ceramics. These glass ceramics can be used as shielding materials for nuclear waste.

  10. Radiation coloration resistant glass

    DOEpatents

    Tomozawa, M.; Watson, E.B.; Acocella, J.

    1986-11-04

    A radiation coloration resistant glass is disclosed which is used in a radiation environment sufficient to cause coloration in most forms of glass. The coloration resistant glass includes higher proportions by weight of water and has been found to be extremely resistant to color change when exposed to such radiation levels. The coloration resistant glass is free of cerium oxide and has more than about 0.5% by weight water content. Even when exposed to gamma radiation of more than 10[sup 7] rad, the coloration resistant glass does not lose transparency. 3 figs.

  11. Radiation coloration resistant glass

    DOEpatents

    Tomozawa, Minoru (Troy, NY); Watson, E. Bruce (Troy, NY); Acocella, John (Troy, NY)

    1986-01-01

    A radiation coloration resistant glass is disclosed which is used in a radiation environment sufficient to cause coloration in most forms of glass. The coloration resistant glass includes higher proportions by weight of water and has been found to be extremely resistant to color change when exposed to such radiation levels. The coloration resistant glass is free of cerium oxide and has more than about 0.5% by weight water content. Even when exposed to gamma radiation of more than 10.sup.7 rad, the coloration resistant glass does not lose transparency.

  12. Acoustics of glass harmonicas

    NASA Astrophysics Data System (ADS)

    Rossing, Thomas D.

    2001-05-01

    Glass musical instruments are probably as old as glassmaking. At least as early as the 17th century it was discovered that wine glasses, when rubbed with a wet finger, produced a musical tone. A collection of glasses played in this manner is called a glass harp. Another type of glass harmonica, called the armonica by its inventor Benjamin Franklin, employs glass bowls or cups turned by a horizontal axle, so the performer need only touch the rim of the bowls as they rotate to set them into vibration. We discuss the modes of vibration of both types of glass harmonica, and describe the different sounds that are emitted by rubbing, tapping, or bowing them. Rubbing with a wet finger tends to excite only the (2,0) mode and its harmonics through a ``stick-slip'' process, while tapping excites the other modes as well.

  13. Application of the hydration thermodynamic model for glass durability under saturated tuff repository conditions

    SciTech Connect

    Ramsey, W.G.; Jantzen, C.M.

    1990-12-31

    The effects of tuff repository groundwater on glass dissolution and surface layer formation was examined utilizing the hydration thermodynamic model. A 28 day MCC-1 monolithic durability test was performed on the following glasses: SiO{sub 2}, obsidian, basalt, medieval window glasses, frit glass, and simulated nuclear waste glass. Silica dissolution was compared with the pH corrected free energy of hydration and shown to have the theoretical slope, ln(1/2.303RT), in agreement with MCC-1 tests using deionized water. X-ray diffraction and scanning electron microscopy identified clays of the saponite family and carbonates, on the glass surfaces leached in tuff groundwater. 31 refs.

  14. Neutron Detection using Lithium Glass Scintillator

    NASA Astrophysics Data System (ADS)

    Wallace, Adam; Rees, Lawrence; Czirr, Bart

    2011-10-01

    We have developed a neutron detector using a thin sheet of lithium-6 glass scintillator. Lithium-6 has a high capture cross-section for neutrons, giving high neutron detection efficiency. One of the difficulties of neutron detection is discriminating between neutron and gamma radiation. We have measured the gamma sensitivity of our detector to be one in 10,000. For nuclear non-proliferation applications, radioactive sources may be shielded. Unlike most neutron detectors, lithium glass detectors are more efficient at detecting neutrons if the source is shielded. We are testing different configurations to optimize the detector's neutron capture efficiency.

  15. Diamond turning of glass

    SciTech Connect

    Blackley, W.S.; Scattergood, R.O.

    1988-12-01

    A new research initiative will be undertaken to investigate the critical cutting depth concepts for single point diamond turning of brittle, amorphous materials. Inorganic glasses and a brittle, thermoset polymer (organic glass) are the principal candidate materials. Interrupted cutting tests similar to those done in earlier research are Ge and Si crystals will be made to obtain critical depth values as a function of machining parameters. The results will provide systematic data with which to assess machining performance on glasses and amorphous materials

  16. Reversing Glass Wettability

    NASA Technical Reports Server (NTRS)

    Frazier, D. O.; Smith, J. E., Jr.; Kaukler, W. F.

    1985-01-01

    Treatment reverses wettability of glassware: Liquids that normally wet glass no longer do, and those that do not wet glass are made to do so. Useful in research on container effects in nucleation and growth of secondary phase from solution. Treatment consists of spreading 3 percent (by weight) solution of silicone oil in hexane isomers over glass, drying in air, and curing at 300 degrees C in vacuum for one hour.

  17. Glass--Sand + Imagination

    NASA Astrophysics Data System (ADS)

    Kolb, Kenneth E.; Kolb, Doris K.

    2000-07-01

    Glass is older than recorded history, and yet it is as new as tomorrow! How, when, or where man first learned to make glass is not known, but we do know that the ancient Egyptians were making glass articles as early as 2,600 B.C.E. (The making of glass beads may have begun as much as 3000 years earlier.) They used it to make jewelry and luxury items, such as decorative bowls and perfume bottles, available only to the wealthy.

  18. Apollo 15 green glasses.

    NASA Technical Reports Server (NTRS)

    Ridley, W. I.; Reid, A. M.; Warner, J. L.; Brown, R. W.

    1973-01-01

    The samples analyzed include 28 spheres, portions of spheres, and angular fragments from soil 15101. Emerald green glasses from other soils are identical to those from 15101. The composition of the green glass is unlike that of any other major lunar glass group. The Fe content is comparable to that in mare basalts, but Ti is much lower. The Mg content is much higher than in most lunar materials analyzed to date, and the Cr content is also high. The low Al content is comparable to that of mare basalt glasses.

  19. Correlation of nuclear criticality safety computer codes with plutonium benchmark experiments and derivation of subcritical limits. [MGBS, TGAN, KEFF, HRXN, GLASS, ANISN, SPBL, and KENO

    SciTech Connect

    Clark, H.K.

    1981-10-01

    A compilation of benchmark critical experiments was made for essentially one-dimensional systems containing plutonium. The systems consist of spheres, series of experiments with cylinders and cuboids that permit extrapolation to infinite cylinders and slabs, and large cylinders for which separability of the neutron flux into a product of spatial components is a good approximation. Data from the experiments were placed in a form readily usable as computer code input. Aqueous solutions of Pu(NO/sub 3/)/sub 4/ are treated as solutions of PuO/sub 2/ in nitric acid. The apparent molal volume of PuO/sub 2/ as a function of plutonium concentration was derived from analyses of solution density data and was incorporated in the Savannah River Laboratory computer codes along with density tables for nitric acid. The biases of three methods of calculation were established by correlation with the benchmark experiments. The oldest method involves two-group diffusion theory and has been used extensively at the Savannah River Laboratory. The other two involve S/sub n/ transport theory with, in one method, Hansen-Roach cross sections and, in the other, cross sections derived from ENDF/B-IV. Subcritical limits were calculated by all three methods. Significant differences were found among the results and between the results and limits currently in the American National Standard for Nuclear Criticality Safety in Operations with Fissionable Materials Outside Reactor (ANSI N16.1), which were calculated by yet another method, despite the normalization of all four methods to the same experimental data. The differences were studied, and a set of subcritical limits was proposed to supplement and in some cases to replace those in the ANSI Standard, which is currently being reviewed.

  20. Rare Earth Phosphate Glass and Glass-Ceramic Proton Conductors

    SciTech Connect

    De Jonghe, Lutgard C.; Ray, Hannah L.; Wang, Ruigang

    2008-12-03

    The structure and conductivity of cerium and lanthanum phosphate glasses and glass-ceramics were investigated. The effects of varying the metal to phosphate ratio in the glasses, doping LaP3O9 glasses with Ce, and recrystallization of CeP3O9 glasses, on the glasses' microstructure and total conductivity were investigated using XRD, SEM, and AC impedance techniques. Strong increases in conductivity occurred when the glasses were recrystallized: the conductivity of a cerium metaphosphate glass increased conductivity after recrystallization from 10-7.5 S/cm to 10-6 S/cm at 400oC.

  1. Importance of glass and brass

    E-print Network

    Dugan, David

    2004-08-17

    The importance of scientific instruments in the scientific revolution, especially brass and glass. Precise lenses and lens grinding, glass vessels for chemical experiments, the advances in astronomy, microscopy and many other areas due to glass...

  2. Glasses and Contact Lenses

    MedlinePLUS

    ... Because everyone's eyes are different, a pair of glasses that makes one person see wonderfully may look terribly blurry to ... a few different prescriptions until you find the one that gives you the clearest vision. It's kind of like a big pair of glasses, but a bunch of different lenses can be ...

  3. Glasses for Children

    MedlinePLUS

    ... a condition called amblyopia, where the vision in one eye does not develop normally. Glasses (and sometimes patching or eye drops) are needed ... she will grow into in a year.(Figures 1 and 2) Lenses made of a material ... that can help keep glasses in the correct position on a child’s face. ...

  4. Surface Conductive Glass.

    ERIC Educational Resources Information Center

    Tanaka, John; Suib, Steven L.

    1984-01-01

    Discusses the properties of surface-conducting glass and the chemical nature of surface-conducting stannic (tin) oxide. Also provides the procedures necessary for the preparation of surface-conducting stannic oxide films on glass substrates. The experiment is suitable for the advanced inorganic chemistry laboratory. (JN)

  5. Getting Started with Glass

    ERIC Educational Resources Information Center

    White, Heather

    2007-01-01

    The metamorphosis of glass when heated is a magical process to students, yet teachers are often reluctant to try it in class. The biggest challenge in working with glass in the classroom is to simplify procedures just enough to ensure student success while maintaining strict safety practices so no students are injured. Project concepts and safety…

  6. Defense HLW Glass Degradation Model

    SciTech Connect

    D. Strachan

    2004-10-20

    The purpose of this report is to document the development of a model for calculating the release rate for radionuclides and other key elements from high-level radioactive waste (HLW) glasses under exposure conditions relevant to the performance of the repository. Several glass compositions are planned for the repository, some of which have yet to be identified (i.e., glasses from Hanford and Idaho National Engineering and Environmental Laboratory). The mechanism for glass dissolution is the same for these glasses and the glasses yet to be developed for the disposal of DOE wastes. All of these glasses will be of a quality consistent with the glasses used to develop this report.

  7. Engineering Glass Passivation Layers -Model Results

    SciTech Connect

    Skorski, Daniel C.; Ryan, Joseph V.; Strachan, Denis M.; Lepry, William C.

    2011-08-08

    The immobilization of radioactive waste into glass waste forms is a baseline process of nuclear waste management not only in the United States, but worldwide. The rate of radionuclide release from these glasses is a critical measure of the quality of the waste form. Over long-term tests and using extrapolations of ancient analogues, it has been shown that well designed glasses exhibit a dissolution rate that quickly decreases to a slow residual rate for the lifetime of the glass. The mechanistic cause of this decreased corrosion rate is a subject of debate, with one of the major theories suggesting that the decrease is caused by the formation of corrosion products in such a manner as to present a diffusion barrier on the surface of the glass. Although there is much evidence of this type of mechanism, there has been no attempt to engineer the effect to maximize the passivating qualities of the corrosion products. This study represents the first attempt to engineer the creation of passivating phases on the surface of glasses. Our approach utilizes interactions between the dissolving glass and elements from the disposal environment to create impermeable capping layers. By drawing from other corrosion studies in areas where passivation layers have been successfully engineered to protect the bulk material, we present here a report on mineral phases that are likely have a morphological tendency to encrust the surface of the glass. Our modeling has focused on using the AFCI glass system in a carbonate, sulfate, and phosphate rich environment. We evaluate the minerals predicted to form to determine the likelihood of the formation of a protective layer on the surface of the glass. We have also modeled individual ions in solutions vs. pH and the addition of aluminum and silicon. These results allow us to understand the pH and ion concentration dependence of mineral formation. We have determined that iron minerals are likely to form a complete incrustation layer and we plan to look more closely at Vivianite [Fe3(PO4)2-8(H2O)] and Siderite [FeCO3] in the next stage of the project.

  8. Sodium and hydrogen analysis of room temperature glass corrosion using low energy Cs SIMS

    NASA Astrophysics Data System (ADS)

    Fearn, S.; McPhail, D. S.; Morris, R. J. H.; Dowsett, M. G.

    2006-07-01

    Corrosion affects commercial float glass production and glasses used to contain high level nuclear waste. In order to prevent the corrosion it is necessary to understand the composition of the corroded glass and the corrosion mechanism taking place. SIMS depth profiling lends itself well to monitoring the compositional changes that occur during the corrosion process. However, most studies have analysed glass that has been corroded using accelerated ageing conditions. In this work a soda-lime glass has been aged at room temperature under known atmospheric humidity for increasing periods of time. The aged glass has then been depth profiled using a low energy (1 keV) Cs beam monitoring both the sodium and hydrogen signals concurrently. The depth profiles show that in the region directly below the glass surface that is severely depleted in sodium, there is an increased level of hydrogen compared to the bulk glass indicating an increase in the water content within this region.

  9. Origin and consequences of silicate glass passivation by surface layers.

    PubMed

    Gin, Stéphane; Jollivet, Patrick; Fournier, Maxime; Angeli, Frédéric; Frugier, Pierre; Charpentier, Thibault

    2015-01-01

    Silicate glasses are durable materials, but are they sufficiently durable to confine highly radioactive wastes for hundreds of thousands years? Addressing this question requires a thorough understanding of the mechanisms underpinning aqueous corrosion of these materials. Here we show that in silica-saturated solution, a model glass of nuclear interest corrodes but at a rate that dramatically drops as a passivating layer forms. Water ingress into the glass, leading to the congruent release of mobile elements (B, Na and Ca), is followed by in situ repolymerization of the silicate network. This material is at equilibrium with pore and bulk solutions, and acts as a molecular sieve with a cutoff below 1?nm. The low corrosion rate resulting from the formation of this stable passivating layer enables the objective of durability to be met, while progress in the fundamental understanding of corrosion unlocks the potential for optimizing the design of nuclear glass-geological disposal. PMID:25695377

  10. Origin and consequences of silicate glass passivation by surface layers

    NASA Astrophysics Data System (ADS)

    Gin, Stéphane; Jollivet, Patrick; Fournier, Maxime; Angeli, Frédéric; Frugier, Pierre; Charpentier, Thibault

    2015-02-01

    Silicate glasses are durable materials, but are they sufficiently durable to confine highly radioactive wastes for hundreds of thousands years? Addressing this question requires a thorough understanding of the mechanisms underpinning aqueous corrosion of these materials. Here we show that in silica-saturated solution, a model glass of nuclear interest corrodes but at a rate that dramatically drops as a passivating layer forms. Water ingress into the glass, leading to the congruent release of mobile elements (B, Na and Ca), is followed by in situ repolymerization of the silicate network. This material is at equilibrium with pore and bulk solutions, and acts as a molecular sieve with a cutoff below 1?nm. The low corrosion rate resulting from the formation of this stable passivating layer enables the objective of durability to be met, while progress in the fundamental understanding of corrosion unlocks the potential for optimizing the design of nuclear glass-geological disposal.

  11. Origin and consequences of silicate glass passivation by surface layers

    PubMed Central

    Gin, Stéphane; Jollivet, Patrick; Fournier, Maxime; Angeli, Frédéric; Frugier, Pierre; Charpentier, Thibault

    2015-01-01

    Silicate glasses are durable materials, but are they sufficiently durable to confine highly radioactive wastes for hundreds of thousands years? Addressing this question requires a thorough understanding of the mechanisms underpinning aqueous corrosion of these materials. Here we show that in silica-saturated solution, a model glass of nuclear interest corrodes but at a rate that dramatically drops as a passivating layer forms. Water ingress into the glass, leading to the congruent release of mobile elements (B, Na and Ca), is followed by in situ repolymerization of the silicate network. This material is at equilibrium with pore and bulk solutions, and acts as a molecular sieve with a cutoff below 1?nm. The low corrosion rate resulting from the formation of this stable passivating layer enables the objective of durability to be met, while progress in the fundamental understanding of corrosion unlocks the potential for optimizing the design of nuclear glass-geological disposal. PMID:25695377

  12. Glass, Brian 1 BRIAN DANIEL GLASS, M.A.

    E-print Network

    Maddox, W. Todd

    Glass, Brian 1 BRIAN DANIEL GLASS, M.A. University Department of Psychology, A8000 The University Making, The University of Texas at Austin #12;Glass, Brian 2 Duties include: Designing and constructing, constructing, and running experiments, statistical analysis. JOURNAL PUBLICATIONS Glass, B. D., Chotibut, T

  13. The Fate Of Silicon During Glass Corrosion Under Alkaline Conditions: A Mechanistic And Kinetic Study With The International Simple Glass

    SciTech Connect

    Gin, Stephane; Jollivet, Patrick; Fournie, Maxime; Berthon, Claude; Wang, Zhaoying; Mitroshkov, Alexandre V.; Zhu, Zihua; Ryan, Joseph V.

    2015-02-01

    International Simple Glass - a six oxide borosilicate glass selected by the international nuclear glass community to improve the understanding of glass corrosion mechanisms and kinetics - was altered at 90°C in a solution initially saturated with respect to amorphous 29-SiO2. The pH90°C, was fixed at 9 at the start of the experiment and raised to 11.5 after 209 d by the addition of KOH. Isotope sensitive analytical techniques were used to analyze the solution and altered glass samples, helping to understand the driving forces and rate limiting processes controlling long-term glass alteration. At pH 9, the corrosion rate continuously drops and the glass slowly transforms into a uniform, homogeneous and isovolumic amorphous alteration layer. The mechanisms responsible for this transformation are water diffusion through the growing alteration layer and ion exchange. We demonstrate that this amorphous alteration layer is not a precipitate resulting from the hydrolysis of the silicate network; it inherits from the glass structure from which the most weakly bonded cations (Na, Ca and B) have been released. At pH 11.5, the alteration process is very different: the high solubility of glass network formers (Si, Al, Zr) triggers the rapid and complete dissolution of the glass (dissolution becomes congruent) and precipitation of amorphous and crystalline phases. Unlike at pH 9 where glass corrosion rate decreased by 3 orders of magnitude likely due to transport-limiting phenomenon within the amorphous alteration layer, the rate at pH 11.5 is maintained at a value close to the forward rate due to both the hydrolysis of the silicate network and the precipitation of CSH and zeolites. This study provides key information for a unified model for glass dissolution.

  14. Glasses for Immobilizing Lanthanide, Alkali, and Alkali-earth Fission Products

    SciTech Connect

    Crum, Jarrod V.; Vienna, John D.

    2009-08-03

    A series of glasses were formulated for the immobilization of a potential waste stream from commercial nuclear fuel reprocessing, the combined lanthanide (LN), alkali, and alkaline earth (Cs/Sr) fission products. These glasses were formulated to meet repository disposal requirements while being processable in a cold-crucible melter. The glasses were fabricated and tested for product consistency test response, phase characterization, density, and glass transition temperature. The results suggest that the combined fission product waste forms are likely to meet repository requirements and generate less glass than if individual streams were vitrified.

  15. Residual Stresses in Glasses

    E-print Network

    M. Ballauff; J. M. Brader; S. U. Egelhaaf; M. Fuchs; J. Horbach; N. Koumakis; M. Krüger; M. Laurati; K. J. Mutch; G. Petekidis; M. Siebenbürger; Th. Voigtmann; J. Zausch

    2013-02-16

    The history dependence of the glasses formed from flow-melted steady states by a sudden cessation of the shear rate $\\dot\\gamma$ is studied in colloidal suspensions, by molecular dynamics simulations, and mode-coupling theory. In an ideal glass, stresses relax only partially, leaving behind a finite persistent residual stress. For intermediate times, relaxation curves scale as a function of $\\dot\\gamma t$, even though no flow is present. The macroscopic stress evolution is connected to a length scale of residual liquefaction displayed by microscopic mean-squared displacements. The theory describes this history dependence of glasses sharing the same thermodynamic state variables, but differing static properties.

  16. EXELFS of Metallic Glasses

    SciTech Connect

    Ito, Y.; Alamgir, F.M.; Schwarz, R.B.; Jain, H.; Williams, D.B.

    1999-11-30

    The feasibility of using extended energy-loss fine structure (EXELFS) obtained from {approximately}1 nm regions of metallic glasses to study their short-range order has been examined. Ionization edges of the metallic glasses in the electron energy-loss spectrum (EELS) have been obtained from PdNiP bulk metallic glass and Ni{sub 2}P polycrystalline powder in a transmission electron microscope. The complexity of EXELFS analysis of L- and M-ionization edges of heavy elements (Z>22, i.e. Ni and Pd) is addressed by theoretical calculations using an ab initio computer code, and its results are compared with the experimental data.

  17. Glass electrolyte composition

    DOEpatents

    Kucera, Gene H. (Downers Grove, IL); Roche, Michael F. (Downers Grove, IL)

    1985-01-01

    An ionically conductive glass is disclosed for use as electrolyte in a high temperature electrochemical cell, particularly a cell with sodium anode and sulfur cathode. The glass includes the constituents Na.sub.2 O, ZrO.sub.2, Al.sub.2 O.sub.3 and SiO.sub.2 in selected proportions to be a single phase solid solution substantially free of crystalline regions and undissolved constituents. Other advantageous properties are an ionic conductivity in excess of 2.times.10.sup.-3 (ohm-cm).sup.-1 at 300.degree. C. and a glass transition temperature in excess of 500.degree. C.

  18. Semiconducting chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Borisova, Z. U.

    Methods for producing semiconducting chalcogenide glasses are discussed, and promising glass compositions are identified in various chalcogenide systems. The systems examined include the binary system As-S and the ternary systems S-Se-Te, As(Ge,P)-Se-Te, As-Se-I, P-As-Se, Bi-Ge-Se, As-Se-Pb, As-Se-Ag, As-Te-Ga, As-Si-Te, and As-Te-Al. The thermal, electrical, magnetic, and other properties of the semiconducting glasses are discussed as a function of their composition.

  19. Glass electrolyte composition

    DOEpatents

    Kucera, G.H.; Roche, M.F.

    1985-01-08

    An ionically conductive glass is disclosed for use as electrolyte in a high temperature electrochemical cell, particularly a cell with sodium anode and sulfur cathode. The glass includes the constituents Na/sub 2/O, ZrO/sub 2/, Al/sub 2/O/sub 3/ and SiO/sub 2/ in selected proportions to be a single phase solid solution substantially free of crystalline regions and undissolved constituents. Other advantageous properties are an ionic conductivity in excess of 2 x 10/sup -3/ (ohm-cm)/sup -1/ at 300/sup 0/C and a glass transition temperature in excess of 500/sup 0/C.

  20. Reference commercial high-level waste glass and canister definition.

    SciTech Connect

    Slate, S.C.; Ross, W.A.; Partain, W.L.

    1981-09-01

    This report presents technical data and performance characteristics of a high-level waste glass and canister intended for use in the design of a complete waste encapsulation package suitable for disposal in a geologic repository. The borosilicate glass contained in the stainless steel canister represents the probable type of high-level waste product that will be produced in a commercial nuclear-fuel reprocessing plant. Development history is summarized for high-level liquid waste compositions, waste glass composition and characteristics, and canister design. The decay histories of the fission products and actinides (plus daughters) calculated by the ORIGEN-II code are presented.

  1. Experimental hydration studies of natural and synthetic glasses

    SciTech Connect

    Bates, J.K.; Abrajano, T.A. Jr.; Ebert, W.L.; Mazer, J.J.; Gerding, T.J.

    1988-01-01

    The results of a series of hydration experiments on natural glasses (Hawaiian basalt, obsidian) and the nuclear waste glass WV-44 done to examine laboratory methods of accelerating reaction processes are summarized. The glasses were reacted in hydrothermal solution and in saturated vapor water. It was found that different reaction rates and processes were found using the differing conditions, and that laboratory efforts to accelerate and duplicate natural processes must amount for the physical processes that occur naturally. 18 refs., 5 figs., 1 tab.

  2. Infrared spectroscopy and hydrogen isotope geochemistry of hydrous silicate glasses

    SciTech Connect

    Epstein, S.; Stolper, E.

    1992-01-01

    The focus of this project is the combined appication of infrared spectroscopy and stable isotope geochemistry to the study of hydrogen-bearing species dissolved in silicate melts and glasses. We are conducting laboratory experiments aimed at determining the fractionation of D and H between melt species (OH and H{sub 2}O) and hydrous vapor and the diffusivities of these species in glasses and melts. Knowledge of these parameters is critical to understanding the behavior of hydrogen isotopes during igneous processes and hydrothermal processes. These results also could be valuable in application of glass technology to development of nuclear waste disposal strategies.

  3. Phase coexistence in proton glass

    SciTech Connect

    Schmidt, V.H.; Trybula, Z.; Pinto, N.J.; Shapiro, S.M.

    1996-11-01

    Proton glasses are crystals of composition M{sub 1{minus}x}(NW{sub 4}){sub x}W{sub 2}AO{sub 4}, where M = K,Rb, W = H,D, A = P,As. For x = 0 there is a ferroelectric (FE) transition, while for x = 1 there is an antiferroelectric (AFE) transition. In both cases, the transition is from a paraelectric (PE) state of tetragonal structure with dynamically disordered hydrogen bonds to an ordered state of orthorhombic structure. For an intermediate x range there is no transition, but the hydrogen rearrangements slow down, and eventually display nonergodic behavior characteristic of glasses. The authors and other have shown from spontaneous polarization, dielectric permittivity, nuclear magnetic resonance, and neutron diffraction experiments that for smaller x there is coexistence of ferroelectric and paraelectric phases, and for larger x there is coexistence of antiferroelectric and paraelectric phases. The authors present a method for analytically describing this coexistence, and the degree to which this coexistence is spatial or temporal.

  4. Pressure dependence of glass transition temperature of elastomeric glasses

    NASA Astrophysics Data System (ADS)

    Pae, K. D.; Tang, C.-L.; Shin, E.-S.

    1984-11-01

    The pressure dependence of the glass transition temperature Tg of two elastomers, Solithane 113 and 3,3-bis(azidomethyl)oxetane/tetrahydrofuran (BAMO/THF) has been determined, employing high-pressure differential thermal analysis (HP-DTA) and dielectric techniques, up to 8.5 kbar. The glasses of the elastomers were named the specific (or Pi glass) or the general glass depending on how the glasses were formed. A Pi glass was formed by lowering temperature under a constant pressure (Pi) and the pressure dependency of the Pi glass was determined after changing pressure only in the glassy state. The general glass consists of a series of specific glasses but the Tg is determined only at pressures under which the glass is formed. The Tg for both glasses increased with increasing pressure. However, the Tg for the Pi glass appears to level off at very high pressures while the Tg does not level off for the general glass. Thermodynamic analysis was made to show that for many general glasses dTg/dP=??/(1+n)?? holds, in which n=1 for Solithane and many other glasses. It is also shown that a modified Gibbs and DiMarzio theory can be used effectively to predict the observed experimental results.

  5. Baseline LAW Glass Formulation Testing

    SciTech Connect

    Kruger, Albert A.; Mooers, Cavin; Bazemore, Gina; Pegg, Ian L.; Hight, Kenneth; Lai, Shan Tao; Buechele, Andrew; Rielley, Elizabeth; Gan, Hao; Muller, Isabelle S.; Cecil, Richard

    2013-06-13

    The major objective of the baseline glass formulation work was to develop and select glass formulations that are compliant with contractual and processing requirements for each of the LAW waste streams. Other objectives of the work included preparation and characterization of glasses with respect to the properties of interest, optimization of sulfate loading in the glasses, evaluation of ability to achieve waste loading limits, testing to demonstrate compatibility of glass melts with melter materials of construction, development of glass formulations to support ILAW qualification activities, and identification of glass formulation issues with respect to contract specifications and processing requirements.

  6. Super ionic conductive glass

    DOEpatents

    Susman, Sherman (Park Forest, IL); Volin, Kenneth J. (Fort Collins, CO)

    1984-01-01

    An ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A.sub.1+x D.sub.2-x/3 Si.sub.x P.sub.3-x O.sub.12-2x/3, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

  7. Seeing Glass Contractors Clearly.

    ERIC Educational Resources Information Center

    Deliberato, Jerry

    2003-01-01

    Offers seven tips for finding and working with an effective glass contractor. For example, schools should consider the company's reputation and longevity of service, and whether it has in-house engineering capabilities. (EV)

  8. Landsborough Glass House

    E-print Network

    Greenslade, Diana

    BLACKALL Redcliffe Bongaree Donnybrook Landsborough Glass House Mountains Beerburrum Peachester Mooloolah CABOOLTURE WTP AL ROUND MT RESERVOIR AL UPPER CABOOLTURE AL/TM BURPENGARY (DALE ST) AL HUME LANE AL WEST

  9. Glass and Glass-Ceramic Materials from Simulated Composition of Lunar and Martian Soils: Selected Properties and Potential Applications

    NASA Technical Reports Server (NTRS)

    Ray, C. S.; Sen, S.; Reis, S. T.; Kim, C. W.

    2005-01-01

    In-situ resource processing and utilization on planetary bodies is an important and integral part of NASA's space exploration program. Within this scope and context, our general effort is primarily aimed at developing glass and glass-ceramic type materials using lunar and martian soils, and exploring various applications of these materials for planetary surface operations. Our preliminary work to date have demonstrated that glasses can be successfully prepared from melts of the simulated composition of both lunar and martian soils, and the melts have a viscosity-temperature window appropriate for drawing continuous glass fibers. The glasses are shown to have the potential for immobilizing certain types of nuclear wastes without deteriorating their chemical durability and thermal stability. This has a direct impact on successfully and economically disposing nuclear waste generated from a nuclear power plant on a planetary surface. In addition, these materials display characteristics that can be manipulated using appropriate processing protocols to develop glassy or glass-ceramic magnets. Also discussed in this presentation are other potential applications along with a few selected thermal, chemical, and structural properties as evaluated up to this time for these materials.

  10. Glass fiber insulation

    SciTech Connect

    Griffith, E.J.; Ngo, T.M.

    1993-06-29

    A composition for a glass fiber insulation is described comprising a loose mat of glass fibers having at least a portion of the surface coated with a water insoluble, non-hygroscopic, amorphous aluminum phosphate polymer having a molar ratio of Al[sub 2]O[sub 3] to P[sub 2]O[sub 5] of less than 1 and providing a substantial thermal resistance.

  11. Metallic glass composition

    DOEpatents

    Kroeger, Donald M. (Knoxville, TN); Koch, Carl C. (Raleigh, NC)

    1986-01-01

    A metallic glass alloy that is either iron-based or nickel-based or based on a mixture of iron and nickel, containing lesser amounts of elements selected from the group boron, silicon carbon and phosphorous to which is added an amount of a ductility enhancing element selected from the group cerium, lanthanum, praseodymium and neodymium sufficient to increase ductility of the metallic glass upon annealing.

  12. Frangible glass canisters

    NASA Technical Reports Server (NTRS)

    Seifert, R.

    1972-01-01

    The need for a canister that can release its contents without disturbing the contents dynamically is discussed. The solution of this problem by the use of a frangible glass canister is considered. The basic theory applicable to frangible glass and the method of initiating a command flaw are discussed. A brief description of the test program and the results of a flight test are presented.

  13. Containerless synthesis of interesting glasses

    NASA Technical Reports Server (NTRS)

    Weinberg, Michael C.

    1990-01-01

    One aspect of containerless glass experimentation was thoroughly examined: glass forming ability. It is argued that although containerless processing will abet glass formation, other ground-based methods can do the job better. However, these methods have limitations, such as sample dimensions and concomitant ability to make property measurements. Most importantly, perhaps, is the observation that glass properties are a function of preparation procedure. Thus, it seems as though there still is an argument for use of containerless processing for glass forming.

  14. Volcanic Glasses: Construction Materials

    NASA Astrophysics Data System (ADS)

    Moskowitz, Samuel E.

    1998-01-01

    Natural glass is the product of rapidly cooled molten rock. Two natural sources of the melt are volcanic eruption and meteoritic impact. Pure glass is an amorphous aggregate. Volcanic glass is a material that could be utilized in the construction of extraterrestrial outposts. Pumice and perlite are volcanic glasses currently used in the building industry. Samples of natural volcanic glass found in the lunar regolith were returned to Earth as part of the Apollo and Luna programs. An alpha proton X-ray spectrometer onboard the Pathfinder recently examined martian rocks located in the vicinity of the lander craft. Preliminary results of chemical composition by weight of SiO2 50-55%, Al203 11-13%, K20 1-2%, Na20 2-5%, CaO 4-6%, MgO 3-7%, FeO 12-14%, S03 2-5%, and MnO <1% were given for two rocks. Parenthetically, the values for K and Mn were perhaps too high, and the analysis was based on X-ray data only. The appreciable amount of silica already found on Mars and empirical evidence to support the hypothesis that the planet once had water sufficient to rapidly cool magma imply the possibility of discovering natural glass of volcanic origin in subsequent missions.

  15. Pourbaix diagram for the prediction of waste glass durability in geologic environments

    SciTech Connect

    Jantzen, C.M.

    1987-01-01

    Dissolution of nuclear waste glass occurs by corrosion mechanisms similar to those of metallurgical and mineralogic systems albeit on different time scales. The effects of imposed pH and oxidation potential (Eh) conditions existing in natural environments on metals and minerals have been quantitatively and phenomenologically described in compendiums of Pourbaix (pH-potential) diagrams. Construction of Pourbaix diagrams to quantify the response of nuclear waste glasses to repository specific pH and Eh conditions is demonstrated. The expected long-term effects of groundwater contact on the durability of nuclear waste glasses can then be unified. 40 refs., 4 figs., 1 tab.

  16. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    SciTech Connect

    Adamson, D; Bradley Pickenheim, B

    2008-11-24

    DWPF is considering replacing irregularly shaped glass frit with spherical glass beads in the Slurry Mix Evaporator (SME) process to decrease the yield stress of the melter feed (a non-Newtonian Bingham Plastic). Pilot-scale testing was conducted on spherical glass beads and glass frit to determine how well the glass beads would transfer when compared to the glass frit. Process Engineering Development designed and constructed the test apparatus to aid in the understanding and impacts that spherical glass beads may have on the existing DWPF Frit Transfer System. Testing was conducted to determine if the lines would plug with the glass beads and the glass frit slurry and what is required to unplug the lines. The flow loop consisted of vertical and horizontal runs of clear PVC piping, similar in geometry to the existing system. Two different batches of glass slurry were tested: a batch of 50 wt% spherical glass beads and a batch of 50 wt% glass frit in process water. No chemicals such as formic acid was used in slurry, only water and glass formers. The glass beads used for this testing were commercially available borosilicate glass of mesh size -100+200. The glass frit was Frit 418 obtained from DWPF and is nominally -45+200 mesh. The spherical glass beads did not have a negative impact on the frit transfer system. The transferring of the spherical glass beads was much easier than the glass frit. It was difficult to create a plug with glass bead slurry in the pilot transfer system. When a small plug occurred from setting overnight with the spherical glass beads, the plug was easy to displace using only the pump. In the case of creating a man made plug in a vertical line, by filling the line with spherical glass beads and allowing the slurry to settle for days, the plug was easy to remove by using flush water. The glass frit proved to be much more difficult to transfer when compared to the spherical glass beads. The glass frit impacted the transfer system to the point that the test apparatus had to be disassembled to dislodge the plugs created in the system.

  17. Competitive formation of glasses and glass-matrix composites

    SciTech Connect

    Lu, Zhao Ping; Ma, D.; Liu, Chain T; Chang, Y. Austin

    2007-01-01

    By systematically investigating the effect of chemical composition on the competitive formation of glasses in various systems, we attempt to address two long-standing scientific puzzles upon metallic glasses, i.e., (i) which composition is the best for forming glasses and glass-matrix composites and (ii) what determines the easy glass-forming composition range in a given alloy system. Our findings have led to the construction of a qualitative microstructure selection map, which is useful for guiding the design of bulkier metallic glasses and glass-matrix composites. In addition, our analysis demonstrates that the classical kinetic treatment of glass formation is insufficient; to analyze glass formation properly, it is necessary to go beyond simple assumptions of single polymorphic solidification during crystallization.

  18. Glass microsphere lubrication

    NASA Technical Reports Server (NTRS)

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

    1991-01-01

    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the manufacturing of the microspheres, while sorting entails deciphering the good microspheres from the bad ones. Each process is discussed in detail.

  19. Ion-implantation effects in glasses

    SciTech Connect

    Arnold, G.W.

    1981-01-01

    Ion implantation can be used to introduce network damage and to alter the chemical composition in glasses. Structural changes can be inferred from IR measurements near 1000 cm/sup -1/ and by optical absorption near 2150 A. Implantation induced damage decreases the implanted volume in fused silica with consequent changes in the refractive index, near-surface hardness, and surface tensile stress. Prior work in these areas is reviewed. Implantation into alkali silicate glasses depletes the alkali content in the implanted region. These changes allow preferential surface crystallization in Li/sub 2/O . 2SiO/sub 2/ glasses. Crystallization of amorphous SiO/sub 2/ can be induced by implantation of Li. Insight into the crystallization process is obtained by observing the associated ion movement using elastic recoil detection (ERD) and optical techniques. Implantation of 20 keV H shows that saturation of implanted H-sites in fused silica occurs at about 2.2 x 10/sup 21/ H/cm/sup 3/ in agreement with estimates of the number of available interstitial sites. Details of H and D interactions in fused silica were studied as a function of fluence and temperature. Results are of interest to studies of corrosion in glasses considered for nuclear waste encapsulation and for components in fusion reactors.

  20. Sol-Gel Glasses

    NASA Technical Reports Server (NTRS)

    Mukherjee, S. P.

    1985-01-01

    Multicomponent homogeneous, ultrapure noncrystalline gels/gel derived glasses are promising batch materials for the containerless glass melting experiments in microgravity. Hence, ultrapure, homogeneous gel precursors could be used to: (1) investigate the effect of the container induced nucleation on the glass forming ability of marginally glass forming compositions; and (2) investigate the influence of gravity on the phase separation and coarsening behavior of gel derived glasses in the liquid-liquid immiscibility zone of the nonsilicate systems having a high density phase. The structure and crystallization behavior of gels in the SiO2-GeO2 as a function of gel chemistry and thermal treatment were investigated. As are the chemical principles involved in the distribution of a second network former in silica gel matrix being investigated. The procedures for synthesizing noncrystalline gels/gel-monoliths in the SiO2-GeO2, GeO2-PbO systems were developed. Preliminary investigations on the levitation and thermal treatment of germania silicate gel-monoliths in the Pressure Facility Acoustic Levitator were done.

  1. Jet penetration in glass

    SciTech Connect

    Moran, B.; Glenn, L.A.; Kusubov, A.

    1991-05-01

    We describe a phenomenological model which accounts for the mechanical response of glass to intense impulsive loading. An important aspect of this response is the dilatancy accompanying fracture. We have also conducted a number of experiments with 38.1-mm diameter precision shaped charges to establish the performance against various targets and to allow evaluation of our model. At 3 charge diameters standoff, the data indicate that both virgin and damaged glass offer better (Bernoulli-scaled) resistance to penetration than either of 4340 steel, or 6061-T6 aluminum alloy. Time-resolved measurements indicate two distinct phases of jet penetration in glass: An initial hydrodynamic phase, and a second phase characterized by a slower penetration velocity. Our calculations show that at early time, a crater is formed around the jet and only the tip of the undisturbed jet interacts with the glass. At late time the glass has collapsed on the jet and degraded penetration continues via a disturbed and fragmented jet.

  2. Glass matrix armor

    DOEpatents

    Calkins, Noel C. (Los Alamos, NM)

    1991-01-01

    An armor system which utilizes glass. A plurality of constraint cells are mounted on a surface of a substrate, which is metal armor plate or a similar tough material, such that the cells almost completely cover the surface of the substrate. Each constraint cell has a projectile-receiving wall parallel to the substrate surface and has sides which are perpendicular to and surround the perimeter of the receiving wall. The cells are mounted such that, in one embodiment, the substrate surface serves as a sixth side or closure for each cell. Each cell has inside of it a plate, termed the front plate, which is parallel to and in contact with substantially all of the inside surface of the receiving wall. The balance of each cell is completely filled with a projectile-abrading material consisting of glass and a ceramic material and, in certain embodiments, a polymeric material. The glass may be in monolithic form or particles of ceramic may be dispersed in a glass matrix. The ceramic material may be in monolithic form or may be in the form of particles dispersed in glass or dispersed in said polymer.

  3. Glass strengthening and patterning methods

    DOEpatents

    Harper, David C; Wereszczak, Andrew A; Duty, Chad E

    2015-01-27

    High intensity plasma-arc heat sources, such as a plasma-arc lamp, are used to irradiate glass, glass ceramics and/or ceramic materials to strengthen the glass. The same high intensity plasma-arc heat source may also be used to form a permanent pattern on the glass surface--the pattern being raised above the glass surface and integral with the glass (formed of the same material) by use of, for example, a screen-printed ink composition having been irradiated by the heat source.

  4. Characterization of Analytical Reference Glass-1 (ARG-1)

    SciTech Connect

    Smith, G.L.

    1993-12-01

    High-level radioactive waste may be immobilized in borosilicate glass at the West Valley Demonstration Project, West Valley, New York, the Defense Waste Processing Facility (DWPF), Aiken, South Carolina, and the Hanford Waste Vitrification Project (HWVP), Richland, Washington. The vitrified waste form will be stored in stainless steel canisters before its eventual transfer to a geologic repository for long-term disposal. Waste Acceptance Product Specifications (WAPS) (DOE 1993), Section 1.1.2 requires that the waste form producers must report the measured chemical composition of the vitrified waste in their production records before disposal. Chemical analysis of glass waste forms is receiving increased attention due to qualification requirements of vitrified waste forms. The Pacific Northwest Laboratory (PNL) has been supporting the glass producers` analytical laboratories by a continuing program of multilaboratory analytical testing using interlaboratory ``round robin`` methods. At the PNL Materials Characterization Center Analytical Round Robin 4 workshop ``Analysis of Nuclear Waste Glass and Related Materials,`` January 16--17, 1990, Pleasanton, California, the meeting attendees decided that simulated nuclear waste analytical reference glasses were needed for use as analytical standards. Use of common standard analytical reference materials would allow the glass producers` analytical laboratories to calibrate procedures and instrumentation, to control laboratory performance and conduct self-appraisals, and to help qualify their various waste forms.

  5. Multicanonical Spin Glass Simulations

    E-print Network

    B. A. Berg; T. Celik

    1992-07-21

    We report a Monte Carlo simulation of the $2D$ Edwards-Anderson spin glass model within the recently introduced multicanonical ensemble. Replica on lattices of size $L^2$ up to $L=48$ are investigated. Once a true groundstate is found, we are able to give a lower bound on the number of statistically independent groundstates sampled. Temperature dependence of the energy, entropy and other quantities of interest are easily calculable. In particular we report the groundstate results. Computations involving the spin glass order parameter are more tedious. Our data indicate that the large $L$ increase of the ergodicity time is reduced to an approximately $V^3$ power law. Altogether the results suggest that the multicanonical ensemble improves the situation of simulations for spin glasses and other systems which have to cope with similar problems of conflicting constraints.

  6. Enhanced resolution and quantitation from `ultrahigh' eld NMR spectroscopy of glasses

    E-print Network

    Puglisi, Joseph

    Enhanced resolution and quantitation from `ultrahigh' ®eld NMR spectroscopy of glasses Scott for nuclear magnetic resonance (NMR) (e.g., 14.1 and 18.8 T) can enhance both resolution and sensitivity-®eld NMR can yield structural information not always available from NMR experiments of glasses at lower

  7. Prediction of radioactive waste glass durability by the hydration thermodynamic model: Application to saturated repository environments

    SciTech Connect

    Jantzen, C.M. ); Ramsey, W.G. . Dept. of Ceramic Engineering)

    1989-01-01

    The effects of groundwater chemistry on glass durability were examined using the hydration thermodynamic model. The relative durabilities of SiO{sub 2}, obsidians, basalts, nuclear waste glasses, medieval window glasses, and a frit glass were determined in tuffaceous groundwater, basaltic groundwater, WIPP-A brine, and Permian-A brine using the monolithic MCC-1 durability test. For all the groundwaters, the free energy of hydration, calculated from the glass composition and the final experimental pH, was linearly related to the logarithm of the measured silica concentration. The linear equation was identical to that observed previously for these glasses during MCC-1 testing in deionized water. In the groundwater-dominated MCC-1 experiments, the pH values for all the glasses tested appeared to be buffered by the groundwater-precipitate chemistry. The behavior of poorly durable glasses demonstrated that the silica release is a function of the ionic strength of the solution. The ionic strength, in turn, reflects the effect of the groundwater chemistry on the pH. Using the hydration thermodynamic model, nuclear waste glass durability in saturated repository environments can be predicted from the glass composition and the groundwater and the groundwater pH. 47 refs., 3 figs. 1 tab.

  8. Transient nucleation in glasses

    NASA Technical Reports Server (NTRS)

    Kelton, K. F.

    1991-01-01

    Nucleation rates in condensed systems are frequently not at their steady state values. Such time dependent (or transient) nucleation is most clearly observed in devitrification studies of metallic and silicate glasses. The origin of transient nucleation and its role in the formation and stability of desired phases and microstructures are discussed. Numerical models of nucleation in isothermal and nonisothermal situations, based on the coupled differential equations describing cluster evolution within the classical theory, are presented. The importance of transient nucleation in glass formation and crystallization is discussed.

  9. THE INFLUENCE OF RADIATION AND MULTIVALENT CATION ADDITIONS ON PHASE SEPARATION AND CRYSTALLIZATION OF GLASS

    EPA Science Inventory

    Recent reviews which have dealt with critical issues regarding the suitability of glasses for nuclear waste disposal have identified liquid-liquid immiscibility and crystallization processes as having the potential to alter significantly storage behavior, especially chemical corr...

  10. Toward acceptance of DWPF glass at a Federal Repository

    SciTech Connect

    Plodinec, M.J.; Stevens, W.R. III; Hacker, B.A.; Baxter, R.G.

    1987-01-01

    Construction of the nations's first facility to immobilize defense high-level nuclear waste, the Defense Waste Processing Facility (DWPF) at the Savannah River Plant, is scheduled to be completed soon. The Department of Energy's Office of Civilian Radioactive Waste Management (OCRWM) has set up a Waste Acceptance Process to provide reasonable assurance that the waste glass produced in the DWPF will be acceptable for permanent storage in a federal repository. As part of this process, detailed specifications have been developed for the waste glass itself, the canister which will contain the waste glass, the sealed canister after it is filled with waste glass, and quality assurance of the product. Savannah River has developed a detailed strategy for demonstrating compliance with each of the specifications, which is documented in a Waste Compliance Plan (WCP). In this paper, the compliance strategy, and progress in implementing the WCP are presented. 12 refs., 3 figs.

  11. Parametric effects on glass reaction in the unsaturated test method

    SciTech Connect

    Woodland, A.B.; Bates, J.K.; Gerding, T.J.

    1991-12-01

    The Unsaturated Test Method has been applied to study glass reaction under conditions that may be present at the potential Yucca Mountain site, currently under evaluation for storage of reprocessed high-level nuclear waste. The results from five separate sets of parametric experiments are presented wherein test parameters ranging from water contact volume to sensitization of metal in contact with the glass were examined. The most significant effect was observed when the volume of water, as controlled by the water inject volume and interval period, was such to allow exfoliation of reacted glass to occur. The extent of reaction was also influenced to a lesser extent by the degree of sensitization of the 304L stainless steel. For each experiment, the release of cations from the glass and alteration of the glass were examined. The major alteration product is a smectite clay that forms both from precipitation from solution and from in-situ alteration of the glass itself. It is this clay that undergoes exfoliation as water drips from the glass. A comparison is made between the results of the parametric experiments with those of static leach tests. In the static tests the rates of release become progressively reduced through 39 weeks while, in contrast, they remain relatively constant in the parametric experiments for at least 300 weeks. This differing behavior may be attributable to the dripping water environment where fresh water is periodically added and where evaporation can occur.

  12. MoO3 incorporation in magnesium aluminosilicate glasses

    NASA Astrophysics Data System (ADS)

    Tan, Shengheng; Ojovan, Michael I.; Hyatt, Neil C.; Hand, Russell J.

    2015-03-01

    Molybdate has a very low solubility in silicate and borosilicate glass systems and its excess presence in nuclear waste glass can cause the formation of a readily soluble "yellow phase". In this study, the incorporation of molybdenum oxide (MoO3) in a magnesium aluminosilicate glass system has been investigated. The prepared glasses show a higher than 90% molybdenum retention rate and up to 5.34 mol% (12.28 wt%) MoO3 can be incorporated into these glasses without causing visible phase separation. The incorporation of MoO3 increases glass density, decreases glass transition and crystallisation temperatures and intensifies Raman bands assigned to vibrations of MoO42- units. When excess molybdate is added liquid-liquid phase separation and crystallisation occurs. The separated phase is spherical, 200-400 nm in diameter and randomly dispersed. Based on powder X-ray diffraction, Raman spectroscopy and transmission electron microscopy, the separated phase is identified as MgMoO4.

  13. Attenuation of Glass Dissolution in the Presence of Natural Additives

    NASA Technical Reports Server (NTRS)

    Sang, Jing C.; Barkatt, Aaron; OKeefe, John A.

    1993-01-01

    The study described here explored the dissolution kinetics of glasses in aqueous environments in systems which included a variety of natural crystalline solids in addition to the glass itself and the aqueous phase. The results demonstrated the possibility of a dramatic decrease in the rate of dissolution of silicate glass in the presence of certain varieties of olivine-based materials. This decrease in dissolution rate was shown to be due to the fact that these additives consist mostly of Mg-based material but also contain minor amounts of Al and Ca. The combined presence of Mg with these minor species affected the corrosion rate of the glass as a whole, including its most soluble components such as boron. The study has potentially important implications to the durability of glasses exposed to natural environments. The results may be relevant to the use of active backfill materials in burial sites for nuclear waste glasses as well as to better understanding of the environmental degradation of natural and ancient glasses.

  14. Interactions between the glass fiber coating and oxidized carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ku-Herrera, J. J.; Avilés, F.; Nistal, A.; Cauich-Rodríguez, J. V.; Rubio, F.; Rubio, J.; Bartolo-Pérez, P.

    2015-03-01

    Chemically oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto commercial E-glass fibers using a dipping procedure assisted by ultrasonic dispersion. In order to investigate the role of the fiber coating (known as "sizing"), MWCNTs were deposited on the surface of as-received E-glass fibers preserving the proprietary coating as well as onto glass fibers which had the coating deliberately removed. Scanning electron microscopy and Raman spectroscopy were used to assess the distribution of MWCNTs onto the fibers. A rather homogeneous coverage with high density of MWCNTs onto the glass fibers is achieved when the fiber coating is maintained. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) analyses of the chemical composition of the glass fiber coating suggest that such coating is a complex mixture with multiple oxygen-containing functional groups such as hydroxyl, carbonyl and epoxy. FTIR and XPS of MWCNTs over the glass fibers and of a mixture of MWCNTs and fiber coating provided evidence that the hydroxyl and carboxyl groups of the oxidized MWCNTs react with the oxygen-containing functional groups of the glass fiber coating, forming hydrogen bonding and through epoxy ring opening. Hydrogen bonding and ester formation between the functional groups of the MWCNTs and the silane contained in the coating are also possible.

  15. Recent experimental advances in spin glasses

    SciTech Connect

    Huang, C.Y.

    1983-01-01

    We present a working definition and a general description of a spin glass. A number of different systems, including metals, semiconductors, and insulators, are discussed. This review presents the current status of experimental spin-glass research with special emphasis on the extent to which the results of this research yield information on spin dynamics. We review the salient features of a series of recent experimental results, published in the past five years, on the susceptibility, magnetization, heat capacity, high-pressure effects, phonon-thermal conductivity, neutron scattering, nuclear, electron, and muon spin resonance. The successful applications of the fractional exponential relaxation function to the frequency dependence of the susceptibility and the time dependence of the thermoremanent magnetization are demonstrated. Concerning the possible existence of the phase transition at the susceptibility cusp temperature, we summarize the experimental evidences. 179 references, 31 figures.

  16. Glass ceramic toughened with tetragonal zirconia

    DOEpatents

    Keefer, K.D.

    1984-02-10

    A phase transformation-toughened glass ceramic and a process for making it are disclosed. A mixture of particulate network-forming oxide, network-modifying oxide, and zirconium oxide is heated to yield a homogeneous melt, and this melt is then heat treated to precipitate an appreciable quantity of tetragonal zirconia, which is retained at ambient temperature to form a phase transformation-toughened glass ceramic. Nuclearing agents and stabilizing agents may be added to the mixture to facilitate processing and improve the ceramic's properties. Preferably, the mixture is first melted at a temperature from 1200 to 1700/sup 0/C and is then heat-treated at a temperature within the range of 800 to 1200/sup 0/C in order to precipitate tetragonal ZrO/sub 2/. The composition, as well as the length and temperature of the heat treatment, must be carefully controlled to prevent solution of the precipitated tetragonal zirconia and subsequent conversion to the monoclinic phase.

  17. Containerless processing of fluoride glass

    NASA Technical Reports Server (NTRS)

    Doremus, Robert H.

    1990-01-01

    Ground-based experiments on glass formation, crystallization, surface tension, vaporization, and chemical durability of a zirconium-barium-lanthanum (ZBL) fluoride glass are summarized. In a container large, columnar grains grew out from the container-glass interface during cooling. The main crystalline phase was alpha BaZrF6. A ZBL glass sphere was levitated acoustically during Shuttle flight STS-11. The glass was melted and then cooled while being levitated (containerless). Crystallization in the recovered sample was very fine and mainly beta BaZr2F10, showing the influence of the container on the nucleation and microstructure of crystallization in the glass. Glass formation should be easier for a containerless glass than in a container.

  18. Spectroscopic studies of glass structure

    SciTech Connect

    Brow, R.K.

    1994-08-01

    Today`s understanding of the molecular-level structure of inorganic glasses has been transformed by the availability of a wide range of sensitive spectroscopic probes. Today we can relate glass composition to quantitative distributions of glass-forming cations and to changes in oxygen bonding and modifying cation geometries. Future spectroscopic studies will result in improved descriptions of anion and cation geometries and should provide glass scientists with the capability to optimize atomic arrangements for specific optical, electrical, and thermal properties.

  19. Glass and ceramics. [lunar resources

    NASA Technical Reports Server (NTRS)

    Haskin, Larry A.

    1992-01-01

    A variety of glasses and ceramics can be produced from bulk lunar materials or from separated components. Glassy products include sintered regolith, quenched molten basalt, and transparent glass formed from fused plagioclase. No research has been carried out on lunar material or close simulants, so properties are not known in detail; however, common glass technologies such as molding and spinning seem feasible. Possible methods for producing glass and ceramic materials are discussed along with some potential uses of the resulting products.

  20. Yesterday's Trash Makes Tomorrow's "Glass"

    ERIC Educational Resources Information Center

    Wayne, Dale

    2010-01-01

    In this article, the author describes a glass art project inspired by Dale Chihuly. This project uses two-liter plastic soda bottles which are cut apart and trimmed. Applying heat using a hair dryer, the plastic curls and takes an uneven blown-glass quality. The "glass" is then painted using acrylic paint. (Contains 2 resources and 1 online…

  1. Triad ''Metal - Enamel - Glass''

    NASA Astrophysics Data System (ADS)

    Mukhina, T.; Petrova, S.; Toporova, V.; Fedyaeva, T.

    2014-10-01

    This article shows how to change the color of metal and glass. Both these materials are self-sufficient, but sometimes used together. For example, enameling. In this case, the adhesion between metal substrate and stekloobraznae enamel layer, which was conducted on a stretching and a bend, was tested.

  2. Shimmering Stained Glass.

    ERIC Educational Resources Information Center

    Simon, Gail Murray

    1998-01-01

    Presents an art lesson for fifth- and sixth-graders where they create a translucent design of colored cellophane on black paper inspired by the stained-glass windows of the Middle Ages and the artwork of Lewis Comfort Tiffany. Enables the students to become crafts people rather than just observers of the past. (CMK)

  3. The Color Glass Condensate

    E-print Network

    F. Gelis; E. Iancu; J. Jalilian-Marian; R. Venugopalan

    2010-02-01

    We provide a broad overview of the theoretical status and phenomenological applications of the Color Glass Condensate effective field theory describing universal properties of saturated gluons in hadron wavefunctions that are extracted from deeply inelastic scattering and hadron-hadron collision experiments at high energies.

  4. Stained-Glass Pastels

    ERIC Educational Resources Information Center

    Laird, Shirley

    2009-01-01

    The author has always liked the look of stained-glass windows. Usually the designs are simplified and the shapes are easier for younger students to draw. This technique seemed to be the perfect place for her fifth-graders to try their hand at color mixing. The smaller spaces and simple shapes were just what she needed for this group. Her students…

  5. "Stained Glass" Landscape Windows

    ERIC Educational Resources Information Center

    Vannata, Janine

    2008-01-01

    Both adults and children alike marvel at the grand vivid stained-glass windows created by American artist Louis Comfort Tiffany. Today he is commonly recognized as one of America's most influential designers and artists throughout the last nineteenth and early twentieth century. In the lesson described in this article, students created their own…

  6. What Glass Ceiling?

    ERIC Educational Resources Information Center

    Lynch, Michael; Post, Katherine

    1996-01-01

    A recent study drawing on data from the Census Bureau and the Bureau of Labor Statistics suggests that the wage gap between men and women has virtually disappeared, and that the so-called "glass ceiling" results more from age and qualifications than from explicit discrimination. (SLD)

  7. THE DEVELOPMENT OF RADIOACTIVE GLASS SURROGATES FOR FALLOUT DEBRIS

    SciTech Connect

    Martha R. Finck; Leigh R. Martin; Russel R. Lewis; Kevin P. Carney; Christopher A. McGrath

    2014-01-01

    The production of glass that emulates fallout is desired for the nuclear forensics community for training and measurement exercises. The composition of nuclear fallout is complex varying isotopic compositions . As the gaseous cloud traverses from hotter to cooler regions of the atmosphere, the processes of condensation and nucleation entrain environmental materials, vaporized nuclear materials and fission products. The elemental and isotopic composition of the fission products is altered due to chemical fractionation (i.e. the fission product composition that would be expected from fission of the original nuclear material is altered by differences in condensation rates of the elements); the fallout may be enriched or depleted in volatile or refractory fission products. This work describes preliminary results to synthesize, irradiate and fractionate the fission product content of irradiated particulate glass using a thermal distillation two hours after irradiation. The glass was synthesized using a solution-based polymerization of tetraethyl orthosilicate. Uranium was incorporated into the glass particulate at trace concentrations during polymerization. The particulate was subjected to a short thermal neutron irradiation then heated to 1273 K approximately 2 hours after the end of irradiation. Fission products of 133, 134, 135I, 132, 134Te, 135Xe, 138Cs and 91, 92Sr were observed to be distilled from the particulate. The results of these preliminary studies are discussed.

  8. Initial state and thermalization in the Color Glass Condensate framework

    E-print Network

    F. Gelis

    2015-09-04

    In this review, I present the description of the early stages of heavy ion collisions at high energy in the Color Glass Condensate framework, from the pre-collision high energy nuclear wavefunction to the point where hydrodynamics may start becoming applicable.

  9. Initial state and thermalization in the Color Glass Condensate framework

    E-print Network

    Gelis, F

    2015-01-01

    In this review, I present the description of the early stages of heavy ion collisions at high energy in the Color Glass Condensate framework, from the pre-collision high energy nuclear wavefunction to the point where hydrodynamics may start becoming applicable.

  10. Volcanic glass as a natural analog for borosilicate waste glass

    SciTech Connect

    Morgenstein, M.E.; Shettel, D.L.

    1994-12-31

    Obsidian and basaltic glass are opposite end-members of natural volcanic glass compositions. Syngenetic and diagenetic tensile failure in basaltic glass (low silica glass) is pervasive and provides abundant alteration fronts deep into the glass structure. Perlitic fracturing in obsidian (high silica glass) limits the alteration zones to an {open_quotes}onion skin{close_quotes} geometry. Borosilicate waste glass behaves similarly to the natural analog of basaltic glass (sideromelane). During geologic time, established and tensile fracture networks form glass cells (a three-dimensional reticulated pattern) where the production of new fracture surfaces increases through time by geometric progression. This suggests that borosilicate glass monoliths will eventually become rubble. Rates of reaction appear to double for every 12C{degrees} of temperature increase. Published leach rates suggest that the entire inventory of certain radionuclides may be released during the 10,000 year regulatory time period. Steam alteration prior to liquid attack combined with pervasive deep tensile failure behavior may suggest that the glass waste form is not license defensible without a metallic- and/or ceramic-type composite barrier as an overpack.

  11. Shedding Synchrotron Light on a Puzzle of Glasses

    ScienceCinema

    Chumakov, Aleksandr [European Synchrotron Radiation Facility, Grenoble, France

    2010-01-08

    Vibrational dynamics of glasses remains a point of controversial discussions. In particular, the density of vibrational states (DOS) reveals an excess of states above the Debye model called "boson peak." Despite the fact that this universal feature for all glasses has been known for more than 35 years, the nature of the boson peak is still not understood. The application of nuclear inelastic scattering via synchrotron radiation perhaps provides a clearer, more consistent picture of the subject. The distinguishing features of nuclear inelastic scattering relative to, e.g., neutron inelastic scattering, are ideal momentum integration and exact scaling of the DOS in absolute units. This allows for reliable comparison to data from other techniques such as Brillouin light scattering. Another strong point is ideal isotope selectivity: the DOS is measured for a single isotope with a specific low-energy nuclear transition. This allows for special "design" of an experiment to study, for instance, the dynamics of only center-of-mass motions. Recently, we have investigated the transformation of the DOS as a function of several key parameters such as temperature, cooling rate, and density. In all cases the transformation of the DOS is sufficiently well described by a transformation of the continuous medium, in particular, by changes of the macroscopic density and the sound velocity. These results suggest a collective sound-like nature of vibrational dynamics in glasses and cast doubts on microscopic models of glass dynamics. Further insight can be obtained in combined studies of glass with nuclear inelastic and inelastic neutron scattering. Applying two techniques, we have measured the energy dependence of the characteristic correlation length of atomic motions. The data do not reveal localization of atomic vibrations at the energy of the boson peak. Once again, the results suggest that special features of glass dynamics are related to extended motions and not to local models.

  12. Shedding Synchrotron Light on a Puzzle of Glasses

    SciTech Connect

    Chumakov, Aleksandr

    2007-12-05

    Vibrational dynamics of glasses remains a point of controversial discussions. In particular, the density of vibrational states (DOS) reveals an excess of states above the Debye model called "boson peak." Despite the fact that this universal feature for all glasses has been known for more than 35 years, the nature of the boson peak is still not understood. The application of nuclear inelastic scattering via synchrotron radiation perhaps provides a clearer, more consistent picture of the subject. The distinguishing features of nuclear inelastic scattering relative to, e.g., neutron inelastic scattering, are ideal momentum integration and exact scaling of the DOS in absolute units. This allows for reliable comparison to data from other techniques such as Brillouin light scattering. Another strong point is ideal isotope selectivity: the DOS is measured for a single isotope with a specific low-energy nuclear transition. This allows for special "design" of an experiment to study, for instance, the dynamics of only center-of-mass motions. Recently, we have investigated the transformation of the DOS as a function of several key parameters such as temperature, cooling rate, and density. In all cases the transformation of the DOS is sufficiently well described by a transformation of the continuous medium, in particular, by changes of the macroscopic density and the sound velocity. These results suggest a collective sound-like nature of vibrational dynamics in glasses and cast doubts on microscopic models of glass dynamics. Further insight can be obtained in combined studies of glass with nuclear inelastic and inelastic neutron scattering. Applying two techniques, we have measured the energy dependence of the characteristic correlation length of atomic motions. The data do not reveal localization of atomic vibrations at the energy of the boson peak. Once again, the results suggest that special features of glass dynamics are related to extended motions and not to local models.

  13. Apollo 12 ropy glasses revisited

    NASA Technical Reports Server (NTRS)

    Wentworth, S. J.; Mckay, D. S.; Lindstrom, D. J.; Basu, A.; Martinez, R. R.; Bogard, D. D.; Garrison, D. H.

    1994-01-01

    We analyzed ropy glasses from Apollo 12 soils 12032 and 12033 by a variety of techniques including SEM/EDX, electron microprobe analysis, INAA, and Ar-39-Ar-40 age dating. The ropy glasses have potassium rare earth elements phosphorous (KREEP)-like compositions different from those of local Apollo 12 mare soils; it is likely that the ropy glasses are of exotic origin. Mixing calculations indicate that the ropy glasses formed from a liquid enriched in KREEP and that the ropy glass liquid also contained a significant amount of mare material. The presence of solar Ar and a trace of regolith-derived glass within the ropy glasses are evidence that the ropy glasses contain a small regolith component. Anorthosite and crystalline breccia (KREEP) clasts occur in some ropy glasses. We also found within these glasses clasts of felsite (fine-grained granitic fragments) very similar in texture and composition to the larger Apollo 12 felsites, which have a Ar-39-Ar-40 degassing age of 800 +/- 15 Ma. Measurements of 39-Ar-40-Ar in 12032 ropy glass indicate that it was degassed at the same time as the large felsite although the ropy glass was not completely degassed. The ropy glasses and felsites, therefore, probably came from the same source. Most early investigators suggested that the Apollo 12 ropy glasses were part of the ejecta deposited at the Apollo 12 site from the Copernicus impact. Our new data reinforce this model. If these ropy glasses are from Copernicus, they provide new clues to the nature of the target material at the Copernicus site, a part of the Moon that has not been sampled directly.

  14. Apollo 12 ropy glasses revisited

    NASA Astrophysics Data System (ADS)

    Wentworth, S. J.; McKay, D. S.; Lindstrom, D. J.; Basu, A.; Martinez, R. R.; Bogard, D. D.; Garrison, D. H.

    1994-05-01

    We analyzed ropy glasses from Apollo 12 soils 12032 and 12033 by a variety of techniques including SEM/EDX, electron microprobe analysis, INAA, and Ar-39-Ar-40 age dating. The ropy glasses have potassium rare earth elements phosphorous (KREEP)-like compositions different from those of local Apollo 12 mare soils; it is likely that the ropy glasses are of exotic origin. Mixing calculations indicate that the ropy glasses formed from a liquid enriched in KREEP and that the ropy glass liquid also contained a significant amount of mare material. The presence of solar Ar and a trace of regolith-derived glass within the ropy glasses are evidence that the ropy glasses contain a small regolith component. Anorthosite and crystalline breccia (KREEP) clasts occur in some ropy glasses. We also found within these glasses clasts of felsite (fine-grained granitic fragments) very similar in texture and composition to the larger Apollo 12 felsites, which have a Ar-39-Ar-40 degassing age of 800 +/- 15 Ma. Measurements of 39-Ar-40-Ar in 12032 ropy glass indicate that it was degassed at the same time as the large felsite although the ropy glass was not completely degassed. The ropy glasses and felsites, therefore, probably came from the same source. Most early investigators suggested that the Apollo 12 ropy glasses were part of the ejecta deposited at the Apollo 12 site from the Copernicus impact. Our new data reinforce this model. If these ropy glasses are from Copernicus, they provide new clues to the nature of the target material at the Copernicus site, a part of the Moon that has not been sampled directly.

  15. Atomistic Model of Physical Ageing in Se-rich As-Se Glasses

    SciTech Connect

    Golovchak,R.; Shpotyuk, O.; Kozdras, A.; Bureau, B.; Vlcek, M.; Ganjoo, A.; Jain, H.

    2007-01-01

    Thermal, optical, X-ray excited and magnetic methods were used to develop a microstructural model of physical ageing in Se-rich glasses. The glass composition As10Se90, possessing a typical cross-linked chain structure, was chosen as a model object for the investigations. The effect of physical ageing in this glass was revealed by differential scanning calorimetry, whereas the corresponding changes in its atomic arrangement were studied by extended X-ray absorption fine structure, Raman and solid-state 77Se nuclear magnetic resonance spectroscopy. Straightening-shrinkage processes are shown to be responsible for the physical ageing in this Se-rich As-Se glass.

  16. Production of glass or glass-ceramic to metal seals with the application of pressure

    DOEpatents

    Kelly, Michael D. (West Alexandria, OH); Kramer, Daniel P. (Dayton, OH)

    1987-11-10

    In a process for preparing a glass or glass-ceramic to metal seal comprising contacting the glass with the metal and heat-treating the glass and metal under conditions whereby the glass to metal seal is effected and, optionally, the glass is converted to a glass-ceramic, an improvement comprises carrying out the heat-treating step using hot isostatic pressing.

  17. Production of glass or glass-ceramic to metal seals with the application of pressure

    DOEpatents

    Kelly, M.D.; Kramer, D.P.

    1985-01-04

    In a process for preparing a glass or glass-ceramic to metal seal comprising contacting the glass with the metal and heat-treating the glass and metal under conditions whereby the glass to metal seal is effected and, optionally, the glass is converted to a glass-ceramic, an improvement comprises carrying out the heat-treating step using hot isostatic pressing.

  18. Profiles in garbage glass containers

    SciTech Connect

    Miller, C.

    1997-09-01

    Glass containers are made from sand, limestone, soda ash, cullet (crushed bottles), and various additives, including those used to color brown, green, or blue bottles. Sixty percent of the glass used in the US is clear (flint) and one-fourth is brown (amber). Almost half of the green bottles are imported wind and beer bottles. Other glass products include flat glass such as windows; fiberglass insulation; and glassware. These products use different manufacturing processes and different additives than container glass. This profile covers only container glass. Glass bottles are commonly collected in curb-side programs. Losses due to breakage and the abrasiveness of glass during collection and processing offset their low collection and processing costs. Breakage solutions include installation of interior baffles or nets in the collection trucks, special glass-only truck compartments, and limiting the number of times glass is transferred after collection before final processing. Ten states require deposits on glass bottles for beer and soft drinks and related items.

  19. Fluoride glass: Crystallization, surface tension

    NASA Technical Reports Server (NTRS)

    Doremus, R. H.

    1988-01-01

    Fluoride glass was levitated acoustically in the ACES apparatus on STS-11, and the recovered sample had a different microstructure from samples cooled in a container. Further experiments on levitated samples of fluoride glass are proposed. These include nucleation, crystallization, melting observations, measurement of surface tension of molten glass, and observation of bubbles in the glass. Ground experiments are required on sample preparation, outgassing, and surface reactions. The results should help in the development and evaluation of containerless processing, especially of glass, in the development of a contaminent-free method of measuring surface tensions of melts, in extending knowledge of gas and bubble behavior in fluoride glasses, and in increasing insight into the processing and properties of fluoride glasses.

  20. The formation of crystals in glasses containing rare earth oxides

    NASA Astrophysics Data System (ADS)

    Fadzil, Syazwani Mohd; Hrma, Pavel; Crum, Jarrod; Siong, Khoo Kok; Ngatiman, Mohammad Fadzlee; Said, Riduan Mt

    2014-02-01

    Korean spent nuclear fuel will reach the capacity of the available temporary storage by 2016. Pyroprocessing and direct disposal seems to be an alternative way to manage and reuse spent nuclear fuel while avoiding the wet reprocessing technology. Pyroprocessing produces several wastes streams, including metals, salts, and rare earths, which must be converted into stabilized form. A suitable form for rare earth immobilization is borosilicate glass. The borosilicate glass form exhibits excellent durability, allows a high waste loading, and is easy to process. In this work, we combined the rare earths waste of composition (in wt%) 39.2Nd2O3-22.7CeO2-11.7La2O3-10.9PrO2-1.3Eu2O3-1.3Gd2O3-8.1Sm2O3-4.8Y2O3 with a baseline glass of composition 60.2SiO2-16.0B2O3-12.6Na2O-3.8Al2O3-5.7CaO-1.7ZrO2. Crystallization in waste glasses occurs as the waste loading increases. It may produce complicate glass processing and affect the product quality. To study crystal formation, we initially made glasses containing 5%, 10% and 15% of La2O3 and then glasses with 5%, 10% and 15% of the complete rare earth mix. Samples were heat-treated for 24 hours at temperatures 800°C to 1150°C in 50°C increments. Quenched samples were analyzed using an optical microscope, scanning electron microscope with energy dispersive spectroscopy, and x-ray diffraction. Stillwellite (LaBSiO5) and oxyapatite (Ca2La8Si6O26) were found in glasses containing La2O3, while oxyapatite (Ca2La8Si6O26 and NaNd9Si6O26) precipitated in glasses with additions of mixed rare earths. The liquidus temperature (TL) of the glasses containing 5%, 10% and 15% La2O3 were 800°C, 959°C and 986°C, respectively; while TL was 825°C, 1059°C and 1267°C for glasses with 5%, 10% and 15% addition of mixed rare earth oxides. The component coefficients TB2O3, TSiO2, TCaO, and TRE2O3 were also evaluated using a recently published study.

  1. Liquidus temperature and chemical durability of selected glasses to immobilize rare earth oxides waste

    NASA Astrophysics Data System (ADS)

    Mohd Fadzil, Syazwani; Hrma, Pavel; Schweiger, Michael J.; Riley, Brian J.

    2015-10-01

    Pyroprocessing is are processing method for managing and reusing used nuclear fuel (UNF) by dissolving it in an electrorefiner with a molten alkali or alkaline earth chloride salt mixture while avoiding wet reprocessing. Pyroprocessing UNF with a LiCl-KCl eutectic salt releases the fission products from the fuel and generates a variety of metallic and salt-based species, including rare earth (RE) chlorides. If the RE-chlorides are converted to oxides, borosilicate glass is a prime candidate for their immobilization because of its durability and ability to dissolve almost any RE waste component into the glass matrix at high loadings. Crystallization that occurs in waste glasses as the waste loading increases may complicate glass processing and affect the product quality. This work compares three types of borosilicate glasses in terms of liquidus temperature (TL): the International Simple Glass designed by the International Working Group, sodium borosilicate glass developed by Korea Hydro and Nuclear Power, and the lanthanide aluminoborosilicate (LABS) glass established in the United States. The LABS glass allows the highest waste loadings (over 50 mass% RE2O3) while possessing an acceptable chemical durability.

  2. Glass matrix armor

    SciTech Connect

    Calkins, N.C.

    1991-09-03

    This patent describes an armor system which utilizes glass. A plurality of constraint cells are mounted on a surface of a substrate, which is metal armor plate or a similar tough material, such that the cells almost completely cover the surface of the substrate. Each constraint cell has a projectile receiving wall parallel to the substrate surface and has sides which are perpendicular to and surround the perimeter of the receiving wall. The cells are mounted such that, in one embodiment, the substrate surface serves as a sixth side or closure for each cell. Each cell has inside of it a plate, termed the front plate, which is parallel to and in contact with substantially all of the insides surface of the receiving wall. The balance of each cell is completely filled with a projectile-abrading material consisting of glass and a ceramic material and, in certain embodiments, a polymeric material.

  3. Using small glass catalogs

    NASA Astrophysics Data System (ADS)

    Tesar, John C.

    2000-07-01

    Changes in glass catalogs from the major manufacturers, Schott, Ohara, Hoya, Corning, and Summita, are a future certainty. The ongoing efforts of these companies to eliminate arsenic, lead, and other environmentally unfriendly materials may well have an additional effect on the size of their catalogs also. We should not assume a zero-sum game, however. Environmental concerns may not lead to permanently smaller catalogs, though many have speculated that in the near term this might be so. However, from the designer's perspective, very small, abbreviated class catalogs, constructed for special purposes, can speed the glass selection process. Several examples will be discussed, based on derivative libraries suggested by Zhang, Shannon, and Walker. Streamlined libraries tailored for special purposes can be used effectively in the latest lens design software. Future software tools may speed this selection process by the use of algorithms that treat the problem as a `black box' using logic tools derived from probability studies of the patent literature.

  4. Chemical durability of soda-lime-aluminosilicate glass for radioactive waste vitrification

    SciTech Connect

    Eppler, F.H.; Yim, M.S.

    1998-09-01

    Vitrification has been identified as one of the most viable waste treatment alternatives for nuclear waste disposal. Currently, the most popular glass compositions being selected for vitrification are the borosilicate family of glasses. Another popular type that has been around in glass industry is the soda-lime-silicate variety, which has often been characterized as the least durable and a poor candidate for radioactive waste vitrification. By replacing the boron constituent with a cheaper substitute, such as silica, the cost of vitrification processing can be reduced. At the same time, addition of network intermediates such as Al{sub 2}O{sub 3} to the glass composition increases the environmental durability of the glass. The objective of this study is to examine the ability of the soda-lime-aluminosilicate glass as an alternative vitrification tool for the disposal of radioactive waste and to investigate the sensitivity of product chemical durability to variations in composition.

  5. NMR and conductivity studies of the mixed glass former effect in lithium borophosphate glasses.

    PubMed

    Storek, Michael; Böhmer, Roland; Martin, Steve W; Larink, Dirk; Eckert, Hellmut

    2012-09-28

    Alkali ion charge transport has been studied in a series of mixed glass former lithium borophosphate glasses of composition 0.33Li(2)O + 0.67[xB(2)O(3) + (1 - x)P(2)O(5)]. The entire concentration range, 0.0 ? x ? 1.0, from pure glassy Li(2)P(4)O(11) to pure glassy Li(2)B(4)O(7) has been examined while keeping the molar fraction of Li(2)O constant. Electrical conductivity measurements and nuclear magnetic resonance techniques such as spin relaxometry, line shape analysis, and stimulated-echo spectroscopy were used to examine the temperature and frequency dependence of the Li(+) ion motion over wide ranges of time scale and temperature. By accurately determining motional time scales and activation energies over the entire composition range the ion dynamics and the charge transport are found to be fastest if the borate and the phosphate fractions are similar. The nonlinear variation of the charge conduction, the most notable feature of the mixed glass former effect, is discussed in terms of the composition dependence of network former units which determine the local glass structure. PMID:23020343

  6. Molten Glass for Thermal Storage: Advanced Molten Glass for Heat Transfer and Thermal Energy Storage

    SciTech Connect

    2012-01-01

    HEATS Project: Halotechnics is developing a high-temperature thermal energy storage system using a new thermal-storage and heat-transfer material: earth-abundant and low-melting-point molten glass. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. Halotechnics new thermal storage material targets a price that is potentially cheaper than the molten salt used in most commercial solar thermal storage systems today. It is also extremely stable at temperatures up to 1200°C—hundreds of degrees hotter than the highest temperature molten salt can handle. Being able to function at high temperatures will significantly increase the efficiency of turning heat into electricity. Halotechnics is developing a scalable system to pump, heat, store, and discharge the molten glass. The company is leveraging technology used in the modern glass industry, which has decades of experience handling molten glass.

  7. Analytical Plan for Roman Glasses

    SciTech Connect

    Strachan, Denis M.; Buck, Edgar C.; Mueller, Karl T.; Schwantes, Jon M.; Olszta, Matthew J.; Thevuthasan, Suntharampillai; Heeren, Ronald M.

    2011-01-01

    Roman glasses that have been in the sea or underground for about 1800 years can serve as the independent “experiment” that is needed for validation of codes and models that are used in performance assessment. Two sets of Roman-era glasses have been obtained for this purpose. One set comes from the sunken vessel the Iulia Felix; the second from recently excavated glasses from a Roman villa in Aquileia, Italy. The specimens contain glass artifacts and attached sediment or soil. In the case of the Iulia Felix glasses quite a lot of analytical work has been completed at the University of Padova, but from an archaeological perspective. The glasses from Aquileia have not been so carefully analyzed, but they are similar to other Roman glasses. Both glass and sediment or soil need to be analyzed and are the subject of this analytical plan. The glasses need to be analyzed with the goal of validating the model used to describe glass dissolution. The sediment and soil need to be analyzed to determine the profile of elements released from the glass. This latter need represents a significant analytical challenge because of the trace quantities that need to be analyzed. Both pieces of information will yield important information useful in the validation of the glass dissolution model and the chemical transport code(s) used to determine the migration of elements once released from the glass. In this plan, we outline the analytical techniques that should be useful in obtaining the needed information and suggest a useful starting point for this analytical effort.

  8. Bioactive glass in tissue engineering

    PubMed Central

    Rahaman, Mohamed N.; Day, Delbert E.; Bal, B. Sonny; Fu, Qiang; Jung, Steven B.; Bonewald, Lynda F.; Tomsia, Antoni P.

    2011-01-01

    This review focuses on recent advances in the development and use of bioactive glass for tissue engineering applications. Despite its inherent brittleness, bioactive glass has several appealing characteristics as a scaffold material for bone tissue engineering. New bioactive glasses based on borate and borosilicate compositions have shown the ability to enhance new bone formation when compared to silicate bioactive glass. Borate-based bioactive glasses also have controllable degradation rates, so the degradation of the bioactive glass implant can be more closely matched to the rate of new bone formation. Bioactive glasses can be doped with trace quantities of elements such as Cu, Zn and Sr, which are known to be beneficial for healthy bone growth. In addition to the new bioactive glasses, recent advances in biomaterials processing have resulted in the creation of scaffold architectures with a range of mechanical properties suitable for the substitution of loaded as well as non-loaded bone. While bioactive glass has been extensively investigated for bone repair, there has been relatively little research on the application of bioactive glass to the repair of soft tissues. However, recent work has shown the ability of bioactive glass to promote angiogenesis, which is critical to numerous applications in tissue regeneration, such as neovascularization for bone regeneration and the healing of soft tissue wounds. Bioactive glass has also been shown to enhance neocartilage formation during in vitro culture of chondrocyte-seeded hydrogels, and to serve as a subchondral substrate for tissue-engineered osteochondral constructs. Methods used to manipulate the structure and performance of bioactive glass in these tissue engineering applications are analyzed. PMID:21421084

  9. Structure and Chemistry in Halide Lead-Tellurite Glasses

    SciTech Connect

    McCloy, John S.; Riley, Brian J.; Lipton, Andrew S.; Windisch, Charles F.; Washton, Nancy M.; Olszta, Matthew J.; Rodriguez, Carmen P.

    2013-02-11

    A series of TeO2-PbO glasses were fabricated with increasing fractions of mixed alkali, alkaline earth, and lanthanide chlorides. The glass and crystal structure was studied with Raman spectroscopy, nuclear magnetic resonance (NMR), X-ray diffraction, and electron microscopy. As the chloride fraction increased, the medium-range order in the glass decreased up to a critical point (~14 mass% of mixed chlorides), above which the glasses became phase-separated. Resulting phases are a TeO2/PbO-rich phase and a crystalline phase rich in alkali chlorides. The 125Te NMR indicates, contrary to previous studies, that Te site distribution did not change with increased concentrations of M+, M2+, and M3+ cations, but rather is controlled by the Te/Pb molar ratio. The 207Pb NMR shows that two Pb species exist and their relative concentration changes nearly linearly with addition of the mixed chlorides, indicating that the additives to the TeO2-PbO glass are accommodated by changing the Pb species. The 23Na and 35Cl NMR indicate that Na and Cl are distributed in the single-phase glass phase up to the critical point, and at higher concentrations partition to crystalline phases. Transmission electron microscopy shows that the sample at the critical point contains ~10 nm seed nuclei that increase in size and concentration with exposure to the electron beam.

  10. Letter report on PCT/Monolith glass ceramic corrosion tests

    SciTech Connect

    Crawford, Charles L.

    2015-09-24

    The Savannah River National Laboratory (SRNL) is collaborating with personnel from Pacific Northwest National Laboratory (PNNL) to study advanced waste form glass ceramics for immobilization of waste from Used Nuclear Fuel (UNF) separations processes. The glass ceramic waste forms take advantage of both crystalline and glassy phases where ‘troublesome’ elements (e.g., low solubility in glass or very long-lived) partition to highly durable ceramic phases with the remainder of elements residing in the glassy phase. The ceramic phases are tailored to create certain minerals or unique crystalline structures that can host the radionuclides by binding them in their specific crystalline network while not adversely impacting the residual glass network (Crum et al., 2011). Glass ceramics have been demonstrated using a scaled melter test performed in a pilot scale (1/4 scale) cold crucible induction melter (CCIM) (Crum et al., 2014; Maio et al., 2015). This report summarizes recent results from both Phase I and Phase II bench scale tests involving crucible fabrication and corrosion testing of glass ceramics using the Product Consistency Test (PCT). Preliminary results from both Phase I and Phase II bench scale tests involving statistically designed matrices have previously been reported (Crawford, 2013; Crawford, 2014).

  11. Tellurium based glasses: A ruthless glass to crystal competition

    NASA Astrophysics Data System (ADS)

    Bureau, Bruno; Danto, Sylvain; Ma, Hong Li; Boussard-Plédel, Catherine; Zhang, Xiang Hua; Lucas, Jacques

    2008-04-01

    Although selenium and tellurium are very close in the periodic table, their ability to form glasses is totally different. Indeed, selenium based glasses are very common and stable whereas pure tellurium glasses need an extremely fast quenching such as splash cooling. Consequently, tellurium glasses are very suitable for the fast and reversible glass to crystal transformation for optical storage applications. In particular, glasses of the ternary system Ge/Sb/Te are the most appropriate to observe phase transformation under laser beam irradiation for the Digital Versatile Disk (DVD) technology. Also, Te based glasses could be very interesting to produce optics for the far infrared, thanks to their low phonon character due to the high atomic weight of Te. Especially, some new tellurium glasses of the system Ge/Ga/Te/I are currently in development for infrared detection of exoplanet within the framework of the Darwin mission. In this contribution an overview covering the past two decades is proposed on the chemistry and the potential applications of these original glasses.

  12. Mixed polyanion glass cathodes: Iron phosphate vanadate glasses

    SciTech Connect

    Kercher, Andrew K; Ramey, Joanne Oxendine; Carroll, Kyler J; Kiggans Jr, James O; Veith, Gabriel M; Meisner, Roberta; Boatner, Lynn A; Dudney, Nancy J

    2014-01-01

    Mixed polyanion (MP) glasses have been investigated for use as cathodes in lithium ion batteries. MP glass cathodes are similar in composition to theoretically promising crystalline polyanionic (CP) cathodes (e.g., lithium cobalt phosphate, lithium manganese silicate), but with proper polyanion substitution, they can be designed to overcome the key shortcomings of CP cathodes, such as poor electrical conductivity and irreversible phase changes. Iron phosphate/vanadate glasses were chosen as a first demonstration of the MP glass concept. Polyanion substitution with vanadate was shown to improve the intercalation capacity of an iron phosphate glass from almost zero to full theoretical capacity. In addition, the MP glass cathodes also exhibited an unexpected second high-capacity electrochemical reaction. X-ray absorption near-edge structure (XANES) and x-ray diffraction (XRD) of cathodes from cells having different states of charge suggested that this second electrochemical reaction is a glass-state conversion reaction. With a first demonstration established, MP glass materials utilizing an intercalation and/or glass-state conversion reaction are promising candidates for future high-energy cathode research.

  13. Atomic dynamics of tin nanoparticles embedded into porous glass

    SciTech Connect

    Parshin, P. P.; Zemlyanov, M. G. Panova, G. Kh.; Shikov, A. A.; Kumzerov, Yu. A.; Naberezhnov, A. A.; Sergueev, I.; Crichton, W.; Chumakov, A. I.; Rueffer, R.

    2012-03-15

    The method of resonant nuclear inelastic absorption of synchrotron radiation has been used to study the phonon spectrum for tin nanoparticles (with a natural isotope mixture) embedded into a porous glassy (silica) matrix with an average pore diameter of 7 nm in comparison to the analogous spectrum of bulk tin enriched with {sup 119}Sn isotope. Differences between the spectra have been observed, which are related to both the dimensional effects and specific structural features of the porous glass-tin nanocomposite. Peculiarities in the dynamics of tin atoms embedded into nanopores of glass are interpreted in terms of a qualitative model of the nanocomposite structure.

  14. Fracture mechanics of cellular glass

    SciTech Connect

    Zwissler, J.G.; Adams, M.A.

    1981-02-01

    The fracture mechanics of cellular glasses (for the structural substrate of mirrored glass for solr concentrator reflecting panels) are discussed. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials were developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region 1 may be slower, by orders of magnitude, than that found in dense glasses.

  15. Waste product profile: Glass containers

    SciTech Connect

    Miller, C.

    1995-09-01

    In 1992, Waste Age initiated the Waste Product Profile series -- brief, factual listings of the solid waste management characteristics of materials in the solid waste stream. This popular series of profiles high-lighted a product, explained how it fit into integrated waste management systems, and provided current data on recycling and markets for the product. Glass containers are made from sand, limestone, soda ash, cullet (crushed bottles), and various additives, including those used to produce green, brown, and blue glass. Other glass products include flat glass, such as windows, and fiberglass products, such as insulation and glassware. These products are manufactured using different processes and different additives than container glass. This profile covers only glass containers.

  16. Fracture mechanics of cellular glass

    NASA Technical Reports Server (NTRS)

    Zwissler, J. G.; Adams, M. A.

    1983-01-01

    The fracture mechanics of cellular glasses (for the structural substrate of mirrored glass for solar concentrator reflecting panels) are discussed. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials were developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region 1 may be slower, by orders of magnitude, than that found in dense glasses. Previously announced in STAR as N82-11209

  17. Fracture mechanics of cellular glass

    NASA Technical Reports Server (NTRS)

    Zwissler, J. G.; Adams, M. A.

    1981-01-01

    The fracture mechanics of cellular glasses (for the structural substrate of mirrored glass for solr concentrator reflecting panels) are discussed. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials were developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region 1 may be slower, by orders of magnitude, than that found in dense glasses.

  18. Long-term alteration of basaltic glass: Mechanisms and rates

    NASA Astrophysics Data System (ADS)

    Parruzot, Benjamin; Jollivet, Patrick; Rébiscoul, Diane; Gin, Stéphane

    2015-04-01

    The long-term behavior study of archaeological artifacts and natural minerals and glasses revealed discrepancies between laboratory and field data. For a better understanding of the cause of these discrepancies and to reinforce the use of basaltic glass as an analog for nuclear waste glasses, this study focuses on the determination of alteration rates and processes of synthetic basaltic glass in residual rate regime. Laboratory batch experiments were performed at high surface-to-volume ratios at 90 and 30 °C for more than 1000 days. In all the experiments, the residual rate regime was reached after about 6 months. The residual alteration rates at 30 and 90 °C were 4.0 ± 1.0 × 10-6 and 9.5 ± 3.2 × 10-6 g·m-2·d-1, respectively. At 90 °C, this residual alteration rate is five orders of magnitude lower than the forward alteration rate (0.8 g·m-2·d-1). Altered powders and monoliths were characterized by Transmission Electron Microscopy and Time-of-Flight Secondary Ion Mass Spectrometry. From glass core to solution, the altered materials are structured as follows: pristine glass, gel (corresponding to the palagonitic layer of natural glasses) and intergranular clays. To assess the passivating properties of this alteration film, we used solid characterization, an isotopically-tagged post-leaching experiment and the measurement of mobile species diffusion coefficients through the alteration film at different stages of reaction using various techniques (solution analysis and X-ray Reflectometry). These characterizations showed that the alteration film formed during residual rate alteration is passivating even without clogged porosity within the gel. Diffusion coefficients of water and alkali metals - respectively diffusing to and from the pristine glass - through the alteration film dropped from 10-20 to 10-19 m2·s-1 during the first alteration stages to 10-25 m2·s-1 in residual rate regime.

  19. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping...154.1320 Sighting ports, tubular gauge glasses, and flat plate type gauge glasses....

  20. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping...154.1320 Sighting ports, tubular gauge glasses, and flat plate type gauge glasses....

  1. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping...154.1320 Sighting ports, tubular gauge glasses, and flat plate type gauge glasses....

  2. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping...154.1320 Sighting ports, tubular gauge glasses, and flat plate type gauge glasses....

  3. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping...154.1320 Sighting ports, tubular gauge glasses, and flat plate type gauge glasses....

  4. Method for heating a glass sheet

    DOEpatents

    Boaz, P.T.

    1998-07-21

    A method for heating a glass sheet includes the steps of heating a glass sheet to a first predetermined temperature and applying microwave energy to the glass sheet to heat the glass sheet to at least a second predetermined temperature to allow the glass sheet to be formed. 5 figs.

  5. Method for heating a glass sheet

    DOEpatents

    Boaz, Premakaran Tucker (Livonia, MI)

    1998-01-01

    A method for heating a glass sheet includes the steps of heating a glass sheet to a first predetermined temperature and applying microwave energy to the glass sheet to heat the glass sheet to at least a second predetermined temperature to allow the glass sheet to be formed.

  6. Glass corrosion in natural environment

    NASA Technical Reports Server (NTRS)

    Thorpe, Arthur N.

    1989-01-01

    A series of studies of the effects of solutes which appear in natural aqueous environments, specifically Mg and Al, under controlled conditions, permit characterization of the retardation of silicate glass leaching in water containing such solutes. In the case of Mg the interaction with the glass appears to consist of exchange with alkali ions present in the glass to a depth of several microns. The effect of Al can be observed at much lower levels, indicating that the mechanism in the case of Al involves irreversible formation of aluminosilicate species at the glass surface.

  7. Crystallization of copper metaphosphate glass

    NASA Technical Reports Server (NTRS)

    Bae, Byeong-Soo; Weinberg, Michael C.

    1993-01-01

    The effect of the valence state of copper in copper metaphosphate glass on the crystallization behavior and glass transition temperature has been investigated. The crystallization of copper metaphosphate is initiated from the surface and its main crystalline phase is copper metaphosphate (Cu(PO)3),independent of the (Cu sup 2+)/(Cu(total)). However, the crystal morphology, the relative crystallization rates, and their temperature dependences are affected by the (Cu sup 2+)/(Cu (total)) ratio in the glass. On the other hand, the totally oxidized glass crystallizes from all over the surface. The relative crystallization rate of the reduced glass to the totally oxidized glass is large at low temperature, but small at high temperature. The glass transition temperature of the glass increases as the (Cu sup 2+)/(Cu(total)) ratio is raised. It is also found that the atmosphere used during heat treatment does not influence the crystallization of the reduced glass, except for the formation of a very thin CuO surface layer when heated in air.

  8. Failure studies of glass fibers

    NASA Astrophysics Data System (ADS)

    Lower, Nathan Paul

    This dissertation is divided into six sections. The first section includes a review of the literature on the mechanical properties of glass, including glass strength. Section two describes a study of the effects of composition of calcium aluminoborosilicate glasses on the inert and room temperature two-point bending failure characteristics of glass fibers, including fatigue and aging effects. Sections three and four include studies of the effects of composition and structure of alkali silicate and aluminosilicate glasses on the inert two-point bending fiber failure properties. Section five describes the inert two-point bending failure results of sodium borate glass fibers. Section six includes a study of the effects of melting time and temperature (i.e. thermal history) on the resulting two-point bending failure properties of glass fibers produced from a variety of glass compositions. Throughout the course of this work, new experimental equipment and techniques were developed so that high quality failure measurements could be obtained. When glass melts were prepared to ensure homogeneity, the failure properties were shown to be sensitive to glass composition and structure and the reproducibility of the failure data was less than for a variety of different silicate glass compositions. Fibers have also been aged under controlled humidity and temperature conditions to characterize the effects of aging time on the failure strain. With the ability to produce and test high quality fiber, a new failure property of glass has been observed. Fibers tested under liquid nitrogen produce failure strains that depend on the testing rate of the two-point bending equipment. In the case of silica glass fibers, failure strain increases with increasing testing rate, an effect attributed to 'normal' inert fatigue behavior. However, some glasses, such as the high alkali silicates and soda lime silicates, show the opposite dependence of failure strain on testing rate, where slower testing rates produce greater failure strains (i.e. an "inert delayed failure effect"). With the ability to determine the intrinsic (flaw-free) failure properties of glass and the dependence of these properties on testing rate, a new insight to the understanding of glass failure and strength with relation to composition and structure may be possible.

  9. Examination of glass-silicon and glass-glass bonding techniques for microfluidic systems

    SciTech Connect

    Raley, N.F.; Davidson, J.C.; Balch, J.W.

    1995-10-23

    We report here on the results of experiments concerning particular bonding processes potentially useful for ultimate miniaturization of microfluidic systems. Direct anodic bonding of continuous thin pyrex glass of 250 {mu}m thickness to silicon substrates gives multiple, large voids in the glass. Etchback of thick glass of 1200 {mu}m thickness bonded to silicon substrates gives thin continuous glass layers of 189 {mu}m thickness without voids over areas of 5 cm {times} 12 cm. Glass was also successfully bonded to glass by thermal bonding at 800{degrees}C over a 5 cm {times} 7 cm area. Anticipated applications include microfabricated DNA sequencing, flow injection analysis, and liquid and gas chromatography microinstruments.

  10. Glass rupture disk

    DOEpatents

    Glass, S. Jill (Albuquerque, NM); Nicolaysen, Scott D. (Albuquerque, NM); Beauchamp, Edwin K. (Albuquerque, NM)

    2002-01-01

    A frangible rupture disk and mounting apparatus for use in blocking fluid flow, generally in a fluid conducting conduit such as a well casing, a well tubing string or other conduits within subterranean boreholes. The disk can also be utilized in above-surface pipes or tanks where temporary and controllable fluid blockage is required. The frangible rupture disk is made from a pre-stressed glass with controllable rupture properties wherein the strength distribution has a standard deviation less than approximately 5% from the mean strength. The frangible rupture disk has controllable operating pressures and rupture pressures.

  11. Multiple Glass Singularities and Isodynamics in a Core-Softened Model for Glass-Forming Systems

    E-print Network

    Sciortino, Francesco

    Multiple Glass Singularities and Isodynamics in a Core-Softened Model for Glass-Forming Systems October 2014; published 18 December 2014) We investigate the slow dynamics of a simple glass former whose: besides the fluid-glass line, the theory predicts a glass-glass line in the temperature-packing fraction

  12. Liquidus temperature and chemical durability of selected glasses to immobilize rare earth oxides waste

    SciTech Connect

    Mohd Fadzil, Syazwani Binti; Hrma, Pavel R.; Schweiger, Michael J.; Riley, Brian J.

    2015-06-30

    Pyroprocessing is a reprocessing method for managing and reusing used nuclear fuel (UNF) by dissolving it in an electrorefiner with a molten alkali or alkaline earth chloride salt mixture while avoiding wet reprocessing. Pyroprocessing UNF with a LiCl-KCl eutectic salt releases the fission products from the fuel and generates a variety of metallic and salt-based species, including rare earth (RE) chlorides. If the RE-chlorides are converted to oxides, borosilicate glass is a prime candidate for their immobilization because of its durability and ability to dissolve almost any RE waste component into the matrix at high loadings. Crystallization that occurs in waste glasses as the waste loading increases may complicate glass processing and affect the product quality. This work compares three types of borosilicate glasses in terms of liquidus temperature (TL): the International Simple Glass designed by the International Working Group, sodium borosilicate glass developed by Korea Hydro and Nuclear Power, and the lanthanide aluminoborosilicate (LABS) glass established in the United States. The LABS glass allows the highest waste loadings (over 50 mass% RE2O3) while possessing an acceptable chemical durability.

  13. POROUS WALL, HOLLOW GLASS MICROSPHERES

    SciTech Connect

    Sexton, W.

    2012-06-30

    Hollow Glass Microspheres (HGM) is not a new technology. All one has to do is go to the internet and Google{trademark} HGM. Anyone can buy HGM and they have a wide variety of uses. HGM are usually between 1 to 100 microns in diameter, although their size can range from 100 nanometers to 5 millimeters in diameter. HGM are used as lightweight filler in composite materials such as syntactic foam and lightweight concrete. In 1968 a patent was issued to W. Beck of the 3M{trademark} Company for 'Glass Bubbles Prepared by Reheating Solid Glass Particles'. In 1983 P. Howell was issued a patent for 'Glass Bubbles of Increased Collapse Strength' and in 1988 H. Marshall was issued a patent for 'Glass Microbubbles'. Now Google{trademark}, Porous Wall, Hollow Glass Microspheres (PW-HGMs), the key words here are Porous Wall. Almost every article has its beginning with the research done at the Savannah River National Laboratory (SRNL). The Savannah River Site (SRS) where SRNL is located has a long and successful history of working with hydrogen and its isotopes for national security, energy, waste management and environmental remediation applications. This includes more than 30 years of experience developing, processing, and implementing special ceramics, including glasses for a variety of Department of Energy (DOE) missions. In the case of glasses, SRS and SRNL have been involved in both the science and engineering of vitreous or glass based systems. As a part of this glass experience and expertise, SRNL has developed a number of niches in the glass arena, one of which is the development of porous glass systems for a variety of applications. These porous glass systems include sol gel glasses, which include both xerogels and aerogels, as well as phase separated glass compositions, that can be subsequently treated to produce another unique type of porosity within the glass forms. The porous glasses can increase the surface area compared to 'normal glasses of a 1 to 2 order of magnitude, which can result in unique properties in areas such as hydrogen storage, gas transport, gas separations and purifications, sensors, global warming applications, new drug delivery systems and so on. One of the most interesting porous glass products that SRNL has developed and patented is Porous Wall, Hollow Glass Microspheres (PW-HGMs) that are being studied for many different applications. The European Patent Office (EPO) just recently notified SRS that the continuation-in-part patent application for the PW-HGMs has been accepted. The original patent, which was granted by the EPO on June 2, 2010, was validated in France, Germany and the United Kingdom. The microspheres produced are generally in the range of 2 to 100 microns, with a 1 to 2 micron wall. What makes the SRNL microspheres unique from all others is that the team in Figure 1 has found a way to induce and control porosity through the thin walls on a scale of 100 to 3000 {angstrom}. This is what makes the SRNL HW-HGMs one-of-a-kind, and is responsible for many of their unique properties and potential for various applications, including those in tritium storage, gas separations, H-storage for vehicles, and even a variety of new medical applications in the areas of drug delivery and MRI contrast agents. SRNL Hollow Glass Microspheres, and subsequent, Porous Wall, Hollow Glass Microspheres are fabricated using a flame former apparatus. Figure 2 is a schematic of the apparatus.

  14. Combined Experimental and Computational Approach to Predict the Glass-Water Reaction

    SciTech Connect

    Pierce, Eric M.; Bacon, Diana H.

    2011-10-01

    The use of mineral and glass dissolution rates measured in laboratory experiments to predict the weathering of primary minerals and volcanic and nuclear waste glasses in field studies requires the construction of rate models that accurately describe the weathering process over geologic timescales. Additionally, the need to model the long-term behavior of nuclear waste glass for the purpose of estimating radionuclide release rates requires that rate models be validated with long-term experiments. Several long-term test methods have been developed to accelerate the glass-water reaction [drip test, vapor hydration test, product consistency test B, and pressurized unsaturated flow (PUF)], thereby reducing the duration required to evaluate long-term performance. Currently, the PUF test is the only method that mimics the unsaturated hydraulic properties expected in a subsurface disposal facility and simultaneously monitors the glass-water reaction. PUF tests are being conducted to accelerate the weathering of glass and validate the model parameters being used to predict long-term glass behavior. A one-dimensional reactive chemical transport simulation of glass dissolution and secondary phase formation during a 1.5-year-long PUF experiment was conducted with the Subsurface Transport Over Reactive Multiphases (STORM) code. Results show that parameterization of the computer model by combining direct bench scale laboratory measurements and thermodynamic data provides an integrated approach to predicting glass behavior over the length of the experiment. Over the 1.5-year-long test duration, the rate decreased from 0.2 to 0.01 g/(m2 day) based on B release for low-activity waste glass LAWA44. The observed decrease is approximately two orders of magnitude higher than the decrease observed under static conditions with the SON68 glass (estimated to be a decrease by four orders of magnitude) and suggests that the gel-layer properties are less protective under these dynamic conditions.

  15. Solution of naturally-ocurring glasses in the geological environment

    NASA Technical Reports Server (NTRS)

    Glass, B. P.

    1982-01-01

    As part of a study to investigate the feasibility of putting nuclear wastes in glass containers and burying them on land or dumping them in the ocean, the amount of solution experience by naturally occurring glasses from two land sites and thirty-four deep sea sites was studied. The glasses are microtektites from three strewn fields and from the Zhamanshin impact crater. The microtektites range in age from 0.7 to 35 m.y. and have a wide range in composition. The weight percent SiO2, for example, ranges from 44.8 to 81.7. Although several criteria for determining the amount of solution were considered, most of the conclusions are based on two criteria: (1) width of cracks, and (2) elevation of silica rich inclusions above the adjacent microtektite surface. All the measurements were made on scanning electron microscope photomicrographs of the microtektites.

  16. Commercial Ion Exchange Resin Vitrification in Borosilicate Glass

    SciTech Connect

    Cicero-Herman, C.A.; Workman, P.; Poole, K.; Erich, D.; Harden, J.

    1998-05-01

    Bench-scale studies were performed to determine the feasibility of vitrification treatment of six resins representative of those used in the commercial nuclear industry. Each resin was successfully immobilized using the same proprietary borosilicate glass formulation. Waste loadings varied from 38 to 70 g of resin/100 g of glass produced depending on the particular resin, with volume reductions of 28 percent to 68 percent. The bench-scale results were used to perform a melter demonstration with one of the resins at the Clemson Environmental Technologies Laboratory (CETL). The resin used was a weakly acidic meth acrylic cation exchange resin. The vitrification process utilized represented a approximately 64 percent volume reduction. Glass characterization, radionuclide retention, offgas analyses, and system compatibility results will be discussed in this paper.

  17. Aspects of the mechanics of metallic glasses

    E-print Network

    Henann, David Lee

    2011-01-01

    Metallic glasses are amorphous materials that possess unique mechanical properties, such as high tensile strengths and good fracture toughnesses. Also, since they are amorphous, metallic glasses exhibit a glass transition, ...

  18. 7 CFR 2902.30 - Glass cleaners.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Glass cleaners. 2902.30 Section 2902...PROCUREMENT Designated Items § 2902.30 Glass cleaners. (a) Definition. Cleaning...designed specifically for use in cleaning glass surfaces, such as windows,...

  19. 7 CFR 2902.30 - Glass cleaners.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Glass cleaners. 2902.30 Section 2902...PROCUREMENT Designated Items § 2902.30 Glass cleaners. (a) Definition. Cleaning...designed specifically for use in cleaning glass surfaces, such as windows,...

  20. 7 CFR 3201.30 - Glass cleaners.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Glass cleaners. 3201.30 Section 3201...PROCUREMENT Designated Items § 3201.30 Glass cleaners. (a) Definition. Cleaning...designed specifically for use in cleaning glass surfaces, such as windows,...

  1. 7 CFR 3201.30 - Glass cleaners.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Glass cleaners. 3201.30 Section 3201...PROCUREMENT Designated Items § 3201.30 Glass cleaners. (a) Definition. Cleaning...designed specifically for use in cleaning glass surfaces, such as windows,...

  2. 7 CFR 3201.30 - Glass cleaners.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Glass cleaners. 3201.30 Section 3201...PROCUREMENT Designated Items § 3201.30 Glass cleaners. (a) Definition. Cleaning...designed specifically for use in cleaning glass surfaces, such as windows,...

  3. Quinary metallic glass alloys

    DOEpatents

    Lin, X.; Johnson, W.L.

    1998-04-07

    At least quinary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10{sup 3}K/s. Such alloys comprise zirconium and/or hafnium in the range of 45 to 65 atomic percent, titanium and/or niobium in the range of 4 to 7.5 atomic percent, and aluminum and/or zinc in the range of 5 to 15 atomic percent. The balance of the alloy compositions comprise copper, iron, and cobalt and/or nickel. The composition is constrained such that the atomic percentage of iron is less than 10 percent. Further, the ratio of copper to nickel and/or cobalt is in the range of from 1:2 to 2:1. The alloy composition formula is: (Zr,Hf){sub a}(Al,Zn){sub b}(Ti,Nb){sub c}(Cu{sub x}Fe{sub y}(Ni,Co){sub z}){sub d} wherein the constraints upon the formula are: a ranges from 45 to 65 atomic percent, b ranges from 5 to 15 atomic percent, c ranges from 4 to 7.5 atomic percent, d comprises the balance, d{hor_ellipsis}y is less than 10 atomic percent, and x/z ranges from 0.5 to 2.

  4. Quinary metallic glass alloys

    DOEpatents

    Lin, Xianghong (Pasadena, CA); Johnson, William L. (Pasadena, CA)

    1998-01-01

    At least quinary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10.sup.3 K/s. Such alloys comprise zirconium and/or hafnium in the range of 45 to 65 atomic percent, titanium and/or niobium in the range of 4 to 7.5 atomic percent, and aluminum and/or zinc in the range of 5 to 15 atomic percent. The balance of the alloy compositions comprise copper, iron, and cobalt and/or nickel. The composition is constrained such that the atomic percentage of iron is less than 10 percent. Further, the ratio of copper to nickel and/or cobalt is in the range of from 1:2 to 2:1. The alloy composition formula is: (Zr,Hf).sub.a (Al,Zn).sub.b (Ti,Nb).sub.c (Cu.sub.x Fe.sub.y (Ni,Co).sub.z).sub.d wherein the constraints upon the formula are: a ranges from 45 to 65 atomic percent, b ranges from 5 to 15 atomic percent, c ranges from 4 to 7.5 atomic percent, d comprises the balance, d.multidot.y is less than 10 atomic percent, and x/z ranges from 0.5 to 2.

  5. CHEMICAL ANALYSIS OF SIMULATED HIGH LEVEL WASTE GLASSES TO SUPPORT SULFATE SOLUBILITY MODELING

    SciTech Connect

    Fox, K.; Marra, J.

    2014-08-14

    The U.S. Department of Energy (DOE), Office of Environmental Management (EM) is sponsoring an international, collaborative project to develop a fundamental model for sulfate solubility in nuclear waste glass. The solubility of sulfate has a significant impact on the achievable waste loading for nuclear waste forms both within the DOE complex and to some extent at U.K. sites. The development of enhanced borosilicate glass compositions with improved sulfate solubility will allow for higher waste loadings and accelerated cleanup missions. Much of the previous work on improving sulfate retention in waste glasses has been done on an empirical basis, making it difficult to apply the findings to future waste compositions despite the large number of glass systems studied. A more fundamental, rather than empirical, model of sulfate solubility in glass, under development at Sheffield Hallam University (SHU), could provide a solution to the issues of sulfate solubility. The model uses the normalized cation field strength index as a function of glass composition to predict sulfate capacity, and has shown early success for some glass systems. The objective of the current scope is to mature the sulfate solubility model to the point where it can be used to guide glass composition development for DOE waste vitrification efforts, allowing for enhanced waste loadings and waste throughput. A series of targeted glass compositions was selected to resolve data gaps in the current model. SHU fabricated these glasses and sent samples to the Savannah River National Laboratory (SRNL) for chemical composition analysis. SHU will use the resulting data to enhance the sulfate solubility model and resolve any deficiencies. In this report, SRNL provides chemical analyses for simulated waste glasses fabricated SHU in support of sulfate solubility model development. A review of the measured compositions revealed that there are issues with the B{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} concentrations missing their targeted values by a significant amount for several of the study glasses. SHU is reviewing the fabrication of these glasses and the chemicals used in batching them to identify the source of these issues. The measured sulfate concentrations were all below their targeted values. This is expected, as the targeted concentrations likely exceeded the solubility limit for sulfate in these glass compositions. Some volatilization of sulfate may also have occurred during fabrication of the glasses. Measurements of the other oxides in the study glasses were reasonably close to their targeted values

  6. Dynamical Crossover in an Ising Spin Glass above Tg: A Muon-Spin-Relaxation Investigation of Fe0:05TiS2

    E-print Network

    Keren, Amit

    terms which can obscure the local magnetic moment effects. Nuclear moments in Fe0:05TiS2 are all zero­12]. It was chosen since a muon is sensitive to the magnetic fields generated by nuclear moments, so it is best to work with spin glasses which have low or zero nuclear moments in order to eliminate parasitic nuclear

  7. Effect of Zn- and Ca-oxides on the structure and chemical durability of simulant alkali borosilicate glasses for immobilisation of UK high level wastes

    NASA Astrophysics Data System (ADS)

    Zhang, Hua; Corkhill, Claire L.; Heath, Paul G.; Hand, Russell J.; Stennett, Martin C.; Hyatt, Neil C.

    2015-07-01

    Compositional modification of United Kingdom high level nuclear waste (HLW) glasses was investigated with the aim of understanding the impact of adopting a ZnO/CaO modified base glass on the vitrified product phase assemblage, glass structure, processing characteristics and dissolution kinetics. Crystalline spinel phases were identified in the vitrified products derived from the Na2O/Li2O and the ZnO/CaO modified base glass compositions; the volume fraction of the spinel crystallites increased with increasing waste loading from 15 to 20 wt%. The spinel composition was influenced by the base glass components; in the vitrified product obtained with the ZnO/CaO modified base glass, the spinel phase contained a greater proportion of Zn, with a nominal composition of (Zn0.60Ni0.20Mg0.20)(Cr1.37Fe0.63)O4. The addition of ZnO and CaO to the base glass was also found to significantly alter the glass structure, with changes identified in both borate and silicate glass networks using Raman spectroscopy. In particular, these glasses were characterised by a significantly higher Q3 species, which we attribute to Si-O-Zn linkages; addition of ZnO and CaO to the glass composition therefore enhanced glass network polymerisation. The increase in network polymerisation, and the presence of spinel crystallites, were found to increase the glass viscosity of the ZnO/CaO modified base glass; however, the viscosities were within the accepted range for nuclear waste glass processing. The ZnO/CaO modified glass compositions were observed to be significantly more durable than the Na2O/Li2O base glass up to 28 days, due to a combination of the enhanced network polymerisation and the formation of Ca/Si containing alteration layers.

  8. Method of determining glass durability

    DOEpatents

    Jantzen, Carol Maryanne (Aiken, SC); Pickett, John Butler (Aiken, SC); Brown, Kevin George (Augusta, GA); Edwards, Thomas Barry (Aiken, SC)

    1998-01-01

    A process for determining one or more leachate concentrations of one or more components of a glass composition in an aqueous solution of the glass composition by identifying the components of the glass composition, including associated oxides, determining a preliminary glass dissolution estimator, .DELTA.G.sub.p, based upon the free energies of hydration for the component reactant species, determining an accelerated glass dissolution function, .DELTA.G.sub.a, based upon the free energy associated with weak acid dissociation, .DELTA.G.sub.a.sup.WA, and accelerated matrix dissolution at high pH, .DELTA.G.sub.a.sup.SB associated with solution strong base formation, and determining a final hydration free energy, .DELTA.G.sub.f. This final hydration free energy is then used to determine leachate concentrations for elements of interest using a regression analysis and the formula log.sub.10 (N C.sub.i (g/L))=a.sub.i +b.sub.i .DELTA.G.sub.f. The present invention also includes a method to determine whether a particular glass to be produced will be homogeneous or phase separated. The present invention is also directed to methods of monitoring and controlling processes for making glass using these determinations to modify the feedstock materials until a desired glass durability and homogeneity is obtained.

  9. Training Guidelines: Glass Furnace Operators.

    ERIC Educational Resources Information Center

    Ceramics, Glass, and Mineral Products Industry Training Board, Harrow (England).

    Technological development in the glass industry is constantly directed towards producing high quality glass at low operating costs. Particularly, changes have taken place in melting methods which mean that the modern furnace operator has greater responsibilities than any of his predecessors. The complexity of control systems, melting rates, tank…

  10. Method of determining glass durability

    DOEpatents

    Jantzen, C.M.; Pickett, J.B.; Brown, K.G.; Edwards, T.B.

    1998-12-08

    A process is described for determining one or more leachate concentrations of one or more components of a glass composition in an aqueous solution of the glass composition by identifying the components of the glass composition, including associated oxides, determining a preliminary glass dissolution estimator, {Delta}G{sub p}, based upon the free energies of hydration for the component reactant species, determining an accelerated glass dissolution function, {Delta}G{sub a}, based upon the free energy associated with weak acid dissociation, {Delta}G{sub a}{sup WA}, and accelerated matrix dissolution at high pH, {Delta}G{sub a}{sup SB} associated with solution strong base formation, and determining a final hydration free energy, {Delta}G{sub f}. This final hydration free energy is then used to determine leachate concentrations for elements of interest using a regression analysis and the formula log{sub 10}(N C{sub i}(g/L))=a{sub i} + b{sub i}{Delta}G{sub f}. The present invention also includes a method to determine whether a particular glass to be produced will be homogeneous or phase separated. The present invention is also directed to methods of monitoring and controlling processes for making glass using these determinations to modify the feedstock materials until a desired glass durability and homogeneity is obtained. 4 figs.

  11. Metal Globules in Agglutinatic Glass

    NASA Astrophysics Data System (ADS)

    Basu, A.; Dorais, M.; McKay, D. S.

    1996-03-01

    Our preliminary analyses show that Ni/Co ratios in micrometer sized metal globules in agglutinatic glass of soil 61181 are mostly above 20, which suggests meteoritic derivation. The excess metal in lunar soils relative to lunar rocks, therefore, is likely to be meteoritic in part and possibly resides in agglutinatic glass.

  12. Refractory Glass Seals for SOFC

    SciTech Connect

    Chou, Y. S.; Stevenson, Jeffry W.

    2011-07-01

    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.

  13. The preparation of uranium-doped glass reference materials for environmental measurements

    NASA Astrophysics Data System (ADS)

    Raptis, K.; Ingelbrecht, C.; Wellum, R.; Alonso, A.; De Bolle, W.; Perrin, R.

    2002-03-01

    Seven different uranium glass powders containing 5 mass% uranium with 235U abundances from natural to highly enriched have been prepared for the IRMM support programme to the International Atomic Energy Agency (IAEA) and for the IRMM external NUSIMEP quality control programme (Nuclear Signatures Interlaboratory Measurement Evaluation Programme). The particles will be primarily used, blended with (inactive) matrix glass powder in various ratios to simulate environmental samples containing "hot" particles in order to assess the performance of various separation and measurement techniques. High-purity borosilicate glass was prepared by blending of powders, melting and grinding by ball milling and jet milling to a powder of about 12 ?m. A quantity of this glass was then blended with U 3O 8, melted and milled to powder. Laser diffraction measurements were made to ensure that the particle size distribution of the uranium glass matched that of the matrix glass in order to ensure homogeneous blending. The final yield was 30-40 g of each uranium glass and 1 kg of matrix glass. The glasses have been certified as reference materials for isotope abundances of uranium.

  14. A literature review of surface alteration layer effects on waste glass behavior

    SciTech Connect

    Feng, X.; Cunnane, J.C.; Bates, J.K.

    1993-01-01

    When in contact with an aqueous solution, nuclear waste glass is subject to a chemical attack that results in progressive alteration. During tills alteration, constituent elements of the glass pass into the solution; elements initially in solution diffuse into, or are adsorbed onto, the solid; and new phases appear. This results in the formation of surface layers on the reacted glass. The glass corrosion and radionuclide release can be better understood by investigating these surface layer effects. In the past decade, there have been numerous studies regarding the effects of surface layers on glass reactions. This paper presents a systematic analysis and summary of the past knowledge regarding the effects of surface layers on glass-water interaction. This paper describes the major formation mechanisms of surface layers; reviews the role of surface layers in controlling mass transport and glass reaction affinity (through crystalline phases, an amorphous silica, a gel layer, or all the components in the glass); and discusses how the surface layers contribute to the retention of radionuclides during glass dissolution.

  15. A literature review of surface alteration layer effects on waste glass behavior

    SciTech Connect

    Feng, X.; Cunnane, J.C.; Bates, J.K.

    1993-05-01

    When in contact with an aqueous solution, nuclear waste glass is subject to a chemical attack that results in progressive alteration. During tills alteration, constituent elements of the glass pass into the solution; elements initially in solution diffuse into, or are adsorbed onto, the solid; and new phases appear. This results in the formation of surface layers on the reacted glass. The glass corrosion and radionuclide release can be better understood by investigating these surface layer effects. In the past decade, there have been numerous studies regarding the effects of surface layers on glass reactions. This paper presents a systematic analysis and summary of the past knowledge regarding the effects of surface layers on glass-water interaction. This paper describes the major formation mechanisms of surface layers; reviews the role of surface layers in controlling mass transport and glass reaction affinity (through crystalline phases, an amorphous silica, a gel layer, or all the components in the glass); and discusses how the surface layers contribute to the retention of radionuclides during glass dissolution.

  16. Iodine valence and local environments in borosilicate waste glasses using X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    McKeown, David A.; Muller, Isabelle S.; Pegg, Ian L.

    2015-01-01

    The radioisotope 129I, a fission product in spent nuclear fuel, has a long half-life, and can be highly mobile in the environment. Iodine K-edge X-ray absorption spectra were collected to characterize the iodine valence and coordination environment in simulated Hanford low activity waste glasses. Both iodine XANES and EXAFS data for eleven borosilicate glasses indicate iodide-like environments within the glass structure, where I- has Na or Li nearest-neighbors, and where the nearest-neighbor cation-type correlates to the most common network-modifying cation in the glass. This is further supported by the systematic increase of iodine incorporation with the combined Na2O + Li2O content in the glass. EXAFS analyses determined I-Na distances near 3.04 Å with coordination numbers near 4.0 and I-Li distances near 2.80 Å with coordination numbers near 3.0. I-Na environments determined for the glasses are similar to the tetrahedral INa4 coordination found in NaI-sodalite. These weakly bound iodine-alkali configurations may be the only pathways for iodine to be retained in the glass. These environments may be precursors to NaI-sodalite crystallization in Na-rich glass. Iodine also shows distinct differences from chlorine in terms of the preferred sites in the glass structure.

  17. Energetics of glass fragmentation: Experiments on synthetic and natural glasses

    NASA Astrophysics Data System (ADS)

    Kolzenburg, S.; Russell, J. K.; Kennedy, L. A.

    2013-11-01

    Natural silicate glasses are an essential component of many volcanic rock types including coherent and pyroclastic rocks; they span a wide range of compositions, occur in diverse environments, and form under a variety of pressure-temperature conditions. In subsurface volcanic environments (e.g., conduits and feeders), melts intersect the thermodynamically defined glass transition temperature to form glasses at elevated confining pressures and under differential stresses. We present a series of room temperature experiments designed to explore the fundamental mechanical and fragmentation behavior of natural (obsidian) and synthetic glasses (Pyrex™) under confining pressures of 0.1-100 MPa. In each experiment, glass cores are driven to brittle failure under compressive triaxial stress. Analysis of the load-displacement response curves is used to quantify the storage of energy in samples prior to failure, the (brittle) release of elastic energy at failure, and the residual energy stored in the post-failure material. We then establish a relationship between the energy density within the sample at failure and the grain-size distributions (D-values) of the experimental products. The relationship between D-values and energy density for compressive fragmentation is significantly different from relationships established by previous workers for decompressive fragmentation. Compressive fragmentation is found to have lower fragmentation efficiency than fragmentation through decompression (i.e., a smaller change in D-value with increasing energy density). We further show that the stress storage capacity of natural glasses can be enhanced (approaching synthetic glasses) through heat treatment.

  18. Database and Interim Glass Property Models for Hanford HLW Glasses

    SciTech Connect

    Hrma, Pavel R.; Piepel, Gregory F.; Vienna, John D.; Cooley, Scott K.; Kim, Dong-Sang; Russell, Renee L.

    2001-07-24

    The purpose of this report is to provide a methodology for an increase in the efficiency and a decrease in the cost of vitrifying high-level waste (HLW) by optimizing HLW glass formulation. This methodology consists in collecting and generating a database of glass properties that determine HLW glass processability and acceptability and relating these properties to glass composition. The report explains how the property-composition models are developed, fitted to data, used for glass formulation optimization, and continuously updated in response to changes in HLW composition estimates and changes in glass processing technology. Further, the report reviews the glass property-composition literature data and presents their preliminary critical evaluation and screening. Finally the report provides interim property-composition models for melt viscosity, for liquidus temperature (with spinel and zircon primary crystalline phases), and for the product consistency test normalized releases of B, Na, and Li. Models were fitted to a subset of the screened database deemed most relevant for the current HLW composition region.

  19. Structure-topology-property correlations of sodium phosphosilicate glasses.

    PubMed

    Hermansen, Christian; Guo, Xiaoju; Youngman, Randall E; Mauro, John C; Smedskjaer, Morten M; Yue, Yuanzheng

    2015-08-14

    In this work, we investigate the correlations among structure, topology, and properties in a series of sodium phosphosilicate glasses with [SiO2]/[SiO2 + P2O5] ranging from 0 to 1. The network structure is characterized by (29)Si and (31)P magic-angle spinning nuclear magnetic resonance and Raman spectroscopy. The results show the formation of six-fold coordinated silicon species in phosphorous-rich glasses. Based on the structural data, we propose a formation mechanism of the six-fold coordinated silicon, which is used to develop a quantitative structural model for predicting the speciation of the network forming units as a function of chemical composition. The structural model is then used to establish a temperature-dependent constraint description of phosphosilicate glass topology that enables prediction of glass transition temperature, liquid fragility, and indentation hardness. The topological constraint model provides insight into structural origin of the mixed network former effect in phosphosilicate glasses. PMID:26277148

  20. Structure-topology-property correlations of sodium phosphosilicate glasses

    NASA Astrophysics Data System (ADS)

    Hermansen, Christian; Guo, Xiaoju; Youngman, Randall E.; Mauro, John C.; Smedskjaer, Morten M.; Yue, Yuanzheng

    2015-08-01

    In this work, we investigate the correlations among structure, topology, and properties in a series of sodium phosphosilicate glasses with [SiO2]/[SiO2 + P2O5] ranging from 0 to 1. The network structure is characterized by 29Si and 31P magic-angle spinning nuclear magnetic resonance and Raman spectroscopy. The results show the formation of six-fold coordinated silicon species in phosphorous-rich glasses. Based on the structural data, we propose a formation mechanism of the six-fold coordinated silicon, which is used to develop a quantitative structural model for predicting the speciation of the network forming units as a function of chemical composition. The structural model is then used to establish a temperature-dependent constraint description of phosphosilicate glass topology that enables prediction of glass transition temperature, liquid fragility, and indentation hardness. The topological constraint model provides insight into structural origin of the mixed network former effect in phosphosilicate glasses.

  1. Structure, surface reactivity and physico-chemical degradation of fluoride containing phospho-silicate glasses

    SciTech Connect

    Kansal, Ishu; Goel, Ashutosh; Tulyaganov, Dilshat U.; Santos, Luis F.; Ferreira, Jose M.

    2011-03-28

    We report on the structure, apatite-forming ability and physicochemical degradation of glasses along fluorapatite [FA; Ca5(PO4)3F] - diopside (Di; CaMgSi2O6) join. A series of glasses with varying FA/Di ratio have been synthesised by melt-quenching technique. The amorphous glasses could be obtained only for compositions up to 40 wt.% of FA. The detailed structural analysis of glasses has been made by infra-red spectroscopy (FTIR), Raman spectroscopy and magic angle spinning-nuclear magnetic resonance spectroscopy (MAS-NMR). Silicon was predominantly present as Q2 (Si) species while phosphorus was found in orthophosphate type environment in all the investigated glasses. The apatite forming ability of glasses was investigated by immersion of glass powders in simulated body fluid (SBF) for time durations varying between 1 h – 28 days. An extensive precipitation of calcite (CaCO3) after immersion in SBF was found in all the glasses which considerably masked the formation of hydroxyapatite [HA; Ca5(PO4)3OH] as depicted by X-ray diffraction (XRD) and FTIR. The possible mechanism favouring formation of calcite instead of HA has been explained on the basis of experimental results obtained for structure of glasses, leaching profile of glass powders in SBF solution and pH variation in SBF solution. Further, physico-chemical degradation of glasses has been studied in accordance with ISO 10993-14 “Biological evaluation of medical devices – Part 14: Identification and quantification of degradation products from ceramics” in Tris HCl and citric acid buffer. All the FA containing glasses exhibited a weight gain (instead of weight loss) after immersion in citric acid buffer due to the formation of different crystalline products.

  2. Containerless glass fiber processing

    NASA Technical Reports Server (NTRS)

    Ethridge, E. C.; Naumann, R. J.

    1986-01-01

    An acoustic levitation furnace system is described that was developed for testing the feasibility of containerless fiber pulling experiments. It is possible to levitate very dense materials such as platinum at room temperature. Levitation at elevated temperatures is much more difficult. Samples of dense heavy metal fluoride glass were levitated at 300 C. It is therefore possible that containerless fiber pulling experiments could be performed. Fiber pulling from the melt at 650 C is not possible at unit gravity but could be possible at reduced gravities. The Acoustic Levitation Furnace is described, including engineering parameters and processing information. It is illustrated that a shaped reflector greatly increases the levitation force aiding the levitation of more dense materials.

  3. A Topological Glass

    E-print Network

    Jean-Pierre Eckmann

    2007-04-07

    We propose and study a model with glassy behavior. The state space of the model is given by all triangulations of a sphere with $n$ nodes, half of which are red and half are blue. Red nodes want to have 5 neighbors while blue ones want 7. Energies of nodes with different numbers of neighbors are supposed to be positive. The dynamics is that of flipping the diagonal of two adjacent triangles, with a temperature dependent probability. We show that this system has an approach to a steady state which is exponentially slow, and show that the stationary state is unordered. We also study the local energy landscape and show that it has the hierarchical structure known from spin glasses. Finally, we show that the evolution can be described as that of a rarefied gas with spontaneous generation of particles and annihilating collisions.

  4. Thermo-physical and structural studies of sodium zinc borovanadate glasses in the region of high concentration of modifier oxides

    SciTech Connect

    Chethana, B.K.; Reddy, C. Narayana; Rao, K.J.

    2012-07-15

    Highlights: ? Highly modified sodium zinc borovanadate glasses. ? Structural model for borovanadate glasses. ? Network forming tendency of ZnO in borovanadate glasses. ? Fragility can be limited to NBO concentration in borovanadate glasses. -- Abstract: This paper reports investigation of Na{sub 2}O and ZnO modified borovanadate glasses in the highly modified regime of compositions. These glasses have been prepared by microwave route. Ultraviolet (UV) and visible, infrared (IR), Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) and Electron Paramagnetic Resonance (EPR) spectroscopies have been used to characterize the speciation in the glasses. Together with the variation of properties such as molar volume and glass transition temperatures, spectroscopic data indicate that at high levels of modification, ZnO tends to behave like network former. It is proposed that the observed variation of all the properties can be reasonably well understood with a structural model. The model considers that the modification and speciation in glasses are strongly determined by the hierarchy of group electronegativities. Further, it is proposed that the width of the transitions of glasses obtained under same condition reflects the fragility of the glasses. An empirical expression has been suggested to quantify fragility on the basis of width of the transition regions.

  5. Defect recovery and damage reduction in borosilicate glasses under double ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Mir, A. H.; Peuget, S.; Toulemonde, M.; Bulot, P.; Jegou, C.; Miro, S.; Bouffard, S.

    2015-11-01

    A sodium borosilicate glass was irradiated sequentially and simultaneously with alpha particles and gold ions. Alpha particles induced partial recovery of the network damage and mechanical properties in the gold pre-irradiated glass, while no such recovery effect was observed during gold irradiation of the alpha pre-irradiated glass. The damage capacity of the gold ions was significantly reduced during simultaneous irradiation with alpha particles and gold ions. These results highlight that the irradiation sequence of the ions plays an important role in controlling the final damage level; and if properly employed, irradiation can be employed to induce defect recovery. Such results are of paramount importance to understand the radiation damage in nuclear reactor components and in nuclear waste glass matrices which are subjected to multiple particle irradiations.

  6. Silicate glass alteration enhanced by iron: origin and long-term implications.

    PubMed

    Michelin, A; Burger, E; Rebiscoul, D; Neff, D; Bruguier, F; Drouet, E; Dillmann, P; Gin, S

    2013-01-15

    Silicate glasses are used as containment matrices for deep geological disposal of nuclear waste arising from spent fuel reprocessing. Understanding the dissolution mechanisms of glasses in contact with iron, an element present in large amounts in the immediate environment (overpack, claystone, etc.) would be a major breakthrough toward predicting radionuclide release in the geosphere after disposal. Two different reacted glass-iron interfaces-a short-term nuclear system and a long-term archeological system-were examined using a multiscale and multianalytical approach including, for the first time on samples of this type, STXM under synchrotron radiation. Comparisons revealed remarkable similarities between the two systems and shed light on Fe-Si interactions, including migration of iron within a porous gel layer and precipitation of Fe-silicates that locally increase short-term glass alteration and are sustainable over the long-term. PMID:23237387

  7. The Effect of Foaming and Silica Dissolution on Melter Feed Rheology during Conversion to Glass

    SciTech Connect

    Marcial, Jose; Chun, Jaehun; Hrma, Pavel R.; Schweiger, Michael J.

    2014-11-23

    As the nuclear waste glass melter feed is converted to molten glass, the feed eventually becomes a continuous glass-forming melt in which dissolving refractory constituents are suspended together with numerous gas bubbles. Knowledge of mechanical properties of the melter feed is crucial for understanding the feed-to-glass conversion as it occurs in the cold cap. We measured the viscosity during heating of the feed and correlated it with the independently determined volume fractions of dissolving quartz particles and the gas phase. The measurement was performed with a rotating spindle rheometer on the melter feed heated at 5 K/min starting at several different temperatures. The effect of quartz particles, gas bubbles, and compositional inhomogeneity on the glass-forming melt viscosity was determined by fitting a linear relationship between log viscosity and volume fractions of suspended phases to data.

  8. Simulation of cooling and solidification of three-dimensional bulk borosilicate glass: effect of structural relaxations

    SciTech Connect

    Barth, N.; George, D.; Ahzi, Said; Remond, Y.; Joulaee, N.; Khaleel, Mohammad A.; Bouyer, F.

    2014-02-28

    Abstract The modeling of the viscoelastic stress evolution and specific volume relaxation of a bulky glass cast is presented in this article and is applied to the experimental cooling process of an inactive nuclear waste vitrification process. The concerned borosilicate glass is solidified and cooled down to ambient temperature in a stainless steel canister, and the thermomechanical response of the package is simulated. There exists a deviant compression of the liquid core due to the large glass package compared to standard tempered glass plates. The stress load development of the glass cast is finally studied for different thermal load scenarios, where the cooling process parameters or the final cooldown rates were changed, and we found a great influence of the studied cooldown rates on the maximum stress buildup at ambient temperature.

  9. Cultivation of Mycoplasmas on glass.

    PubMed

    Purcell, R H; Valdesuso, J R; Cline, W L; James, W D; Chanock, R M

    1971-02-01

    Eight Mycoplasma species of human origin were successfully cultivated on glass. Complement-fixing (CF) antigens prepared from glass-adherent mycoplasmas were potent, specific, and free from anticomplementary activity. PPLO broth medium supplemented with 1 to 5% PPLO serum fraction (bovine), 2.5% fresh yeast extract, and 1% glucose (glycolytic species) or 1% arginine (arginine-utilizing species) supported moderate to luxuriant growth of mycoplasmas on glass. The potency of CF antigens prepared from glass-adherent mycoplasmas varied with the species of Mycoplasma tested and the duration of incubation. When the potency of CF antigens prepared from glass-adherent mycoplasmas was compared with that material sedimented from the broth phase of the same culture, three patterns of growth were observed: M. hominis and M. orale type 2 grew preferentially in the broth phase; M. salivarium, M. orale types 1 and 3, M. pneumoniae, and M. lipophilum preferentially adhered to the glass; and M. fermentans was biphasic. The growth of mycoplasmas on glass provides a simple means of concentrating and purifying such organisms for immunological and biochemical studies. PMID:5547544

  10. Cultivation of Mycoplasmas on Glass

    PubMed Central

    Purcell, R. H.; Valdesuso, J. R.; Cline, W. L.; James, W. D.; Chanock, R. M.

    1971-01-01

    Eight Mycoplasma species of human origin were successfully cultivated on glass. Complement-fixing (CF) antigens prepared from glass-adherent mycoplasmas were potent, specific, and free from anticomplementary activity. PPLO broth medium supplemented with 1 to 5% PPLO serum fraction (bovine), 2.5% fresh yeast extract, and 1% glucose (glycolytic species) or 1% arginine (arginine-utilizing species) supported moderate to luxuriant growth of mycoplasmas on glass. The potency of CF antigens prepared from glass-adherent mycoplasmas varied with the species of Mycoplasma tested and the duration of incubation. When the potency of CF antigens prepared from glass-adherent mycoplasmas was compared with that material sedimented from the broth phase of the same culture, three patterns of growth were observed: M. hominis and M. orale type 2 grew preferentially in the broth phase; M. salivarium, M. orale types 1 and 3, M. pneumoniae, and M. lipophilum preferentially adhered to the glass; and M. fermentans was biphasic. The growth of mycoplasmas on glass provides a simple means of concentrating and purifying such organisms for immunological and biochemical studies. PMID:5547544

  11. Automated glass-fragmentation analysis

    NASA Astrophysics Data System (ADS)

    Gordon, Gaile G.

    1996-02-01

    This paper describes a novel automated inspection process for tempered safety glass. The system is geared toward the European Community (EC) import regulations which are based on fragment count and dimensions in a fractured glass sample. The automation of this test presents two key challenges: image acquisition, and robust particle segmentation. The image acquisition must perform well both for clear and opaque glass. Opaque regions of glass are common in the American auto industry due to painted styling or adhesives (e.g. defroster cables). The system presented uses a multiple light source, reflected light imaging technique, rather than transmitted light imaging which is often used in manual versions of this inspection test. Segmentation of the glass fragments in the resulting images must produce clean and completely connected crack lines in order to compute the correct particle count. Processing must therefore be robust with respect to noise in the imaging process such as dust and glint on the glass. The system presented takes advantage of mathematical morphology algorithms, in particular the watershed algorithm, to perform robust preprocessing and segmentation. Example images and image segmentation results are shown for tempered safety glass which has been painted on the outside edges for styling purposes.

  12. Rhenium volatilization in waste glasses

    NASA Astrophysics Data System (ADS)

    Xu, Kai; Pierce, David A.; Hrma, Pavel; Schweiger, Michael J.; Kruger, Albert A.

    2015-09-01

    We investigated volatilization of rhenium (Re), sulfur, cesium, and iodine during the course of conversion of high-level waste melter feed to glass and compared the results for Re volatilization with those in low-activity waste borosilicate glasses. Whereas Re did not volatilize from high-level waste feed heated at 5 K min-1 until 1000 °C, it began to volatilize from low-activity waste borosilicate glass feeds at ?600 °C, a temperature ?200 °C below the onset temperature of evaporation from pure KReO4. Below 800 °C, perrhenate evaporation in low-activity waste melter feeds was enhanced by vigorous foaming and generation of gases from molten salts as they reacted with the glass-forming constituents. At high temperatures, when the glass-forming phase was consolidated, perrhenates were transported to the top surface of glass melt in bubbles, typically together with sulfates and halides. Based on the results of this study (to be considered preliminary at this stage), the high-level waste glass with less foaming and salts appears a promising medium for technetium immobilization.

  13. Glass ceramic seals to inconel

    DOEpatents

    McCollister, Howard L. (Albuquerque, NM); Reed, Scott T. (Albuquerque, NM)

    1983-11-08

    A glass ceramic composition prepared by subjecting a glass composition comprising, by weight, 65-80% SiO.sub.2, 8-16%, Li.sub.2 O, 2-8% , Al.sub.2 O.sub.3, 1-8% K.sub.2 O, 1-5% P.sub.2 O.sub.5 and 1.5-7% B.sub.2 O.sub.3, to the following processing steps of heating the glass composition to a temperature sufficient to crystallize lithium metasilicate therein, holding the glass composition at a temperature and for a time period sufficient to dissolve the lithium metasilicate therein thereby creating cristobalite nucleii, cooling the glass composition and maintaining the composition at a temperature and for a time period sufficient to recrystallize lithium metasilicate therein, and thermally treating the glass composition at a temperature and for a time period sufficient to cause growth of cristobalite and further crystallization of lithium metasilicate producing a glass ceramic composition having a specific thermal expansion coefficient and products containing said composition.

  14. The role of test parameters on the kinetics and thermodynamics of glass leaching. [None

    SciTech Connect

    Jantzen, C M

    1988-01-01

    The relative durabilities of nuclear waste, natural, and ancient glasses have been assessed by standard laboratory leach tests. Different test conditions result in different glass surface areas (SA), leachant volumes (V), and test durations (t). Leachate concentrations are known to be a parabolic function of the kinetic test parameter SAV/center dot/t. Based on durability experiments of glass monoliths at low (SAV)/center dot/ glass durability has been shown to be a logarithmic function of the thermodynamic hydration free energy, ..delta..G/sub hyd/. The thermodynamic hydration free energy, ..delta..G/sub hyd/, can be calculated from glass composition and solution pH. In the repository environment high effective glass surface areas to solution volume ratios may occur as a result of slow groundwater flow rates. The application of hydration thermodynamics to crushed glass, high (SAV)/center dot/t, durability tests has been demonstrated. The relative contributions of the kinetic test parameters, (SAV)/center dot/t, and the thermodynamic parameter, ..delta..G/sub hyd/, have been shown to define a plane in ..delta..G/sub hyd/-concentration-(SAV)/center dot/t space. At constant test conditions, e.g. constant (SAV/center dot/t, the intersection with this surface indicates that all /delta G//sub hyd/-concentration plots should have similar slopes and predict the same relative durabilities for various glasses as a function of glass composition. Using this approach, the durability of nuclear waste glasses has been interpolated to be -- 10/sup 6/ years and no less than 10/sup 3/ years. 28 refs., 24 figs.

  15. Combined Experimental and Computational Approach to Predict the Glass-Water Reaction

    SciTech Connect

    Pierce, Eric M; Bacon, Diana

    2011-01-01

    The use of mineral and glass dissolution rates measured in laboratory experiments to predict the weathering of primary minerals and volcanic and nuclear waste glasses in field studies requires the construction of rate models that accurately describe the weathering process over geologic time-scales. Additionally, the need to model the long-term behavior of nuclear waste glass for the purpose of estimating radionuclide release rates requires that rate models are validated with long-term experiments. Several long-term test methods have been developed to accelerate the glass-water reaction [drip test, vapor hydration test, product consistency test-B, and pressurized unsaturated flow (PUF)], thereby reducing the duration required to evaluate long-term performance. Currently, the PUF test is the only method that mimics the unsaturated hydraulic properties expected in a subsurface disposal facility and simultaneously monitors the glass-water reaction. PUF tests are being conducted to accelerate the weathering of glass and validate the model parameters being used to predict long-term glass behavior. A one-dimensional reactive chemical transport simulation of glass dissolution and secondary phase formation during a 1.5-year long PUF experiment was conducted with the subsurface transport over reactive multi-phases code. Results show that parameterization of the computer model by combining direct bench-scale laboratory measurements and thermodynamic data provides an integrated approach to predicting glass behavior over the length of the experiment. Over the 1.5-year long test duration, the rate decreased from 0.2 to 0.01 g/(m2 d) base on B release. The observed decrease is approximately two orders of magnitude higher than the decrease observed under static conditions with the SON68 glass (estimated to be a decrease by 4 orders of magnitude) and suggest the gel-layer properties are less protective under these dynamic conditions.

  16. Glass enamel and glass-ceramic coatings for chemical apparatus

    SciTech Connect

    Es'kov, A.S.; Oleinik, M.I.; Shabrova, E.A.

    1984-05-01

    Among the known anticorrosion coatings used in chemical engineering, glass enamel base coatings are distinguished by such advantages as a high degree of continuity and chemical resistance. The paper describes basic principles for the creation of acid and alkali resistant glass enamel and ceramic coatings for chemical apparatus. As the result of investgations, glass enamel coatings with increased electrical conductivity and also experimental production compositions of chemical, temperature and radiation resistant coatings for protection of chemical equipment of 12Kh18N10T stainless steel have been developed. The coatings have successfully passed testing under service conditions. A new type of coating is short-term glass enamel, which may be recommended for use in chemical machinery manufacturing and other branches of industry in oxidation-free heating and forming of stainless steels.

  17. Glass microspheres for medical applications

    NASA Astrophysics Data System (ADS)

    Conzone, Samuel David

    Radioactive dysprosium lithium borate glass microspheres have been developed as biodegradable radiation delivery vehicles for the radiation synovectomy treatment of rheumatoid arthritis. Once injected into a diseased joint, the microspheres deliver a potent dose of radiation to the diseased tissue, while a non-uniform chemical reaction converts the glass into an amorphous, porous, hydrated dysprosium phosphate reaction product. The non-radioactive, lithium-borate component is dissolved from the glass (up to 94% weight loss), while the radioactive 165Dy reacts with phosphate anions in the body fluids, and becomes "chemically" trapped in a solid, dysprosium phosphate reaction product that has the same size as the un-reacted glass microsphere. Ethylene diamine tetraacetate (EDTA) chelation therapy can be used to dissolve the dysprosium phosphate reaction product after the radiation delivery has subsided. The dysprosium phosphate reaction product, which formed in vivo in the joint of a Sprague-Dawley rat, was dissolved by EDTA chelation therapy in <1 week, without causing any detectable joint damage. The combination of dysprosium lithium borate glass microspheres and EDTA chelation therapy provides an unique "tool" for the medical community, which can deliver a large dose (>100 Gy) of localized beta radiation to a treatment site within the body, followed by complete biodegradability. The non-uniform reaction process is a desirable characteristic for a biodegradable radiation delivery vehicle, but it is also a novel material synthesis technique that can convert a glass to a highly porous materials with widely varying chemical composition by simple, low-temperature, glass/solution reaction. The reaction product formed by nonuniform reaction occupies the same volume as the un-reacted glass, and after drying for 1 h at 300°C, has a specific surface area of ?200 m2/g, a pore size of ?30 nm, and a nominal crushing strength of ?10 MPa. Finally, rhenium glass microspheres, composed of micron-sized, metallic rhenium particles dispersed within a magnesium alumino borate glass matrix were produced by sintering ReO2 powder and glass frit at 1050°C. A 50 mg injection of radioactive rhenium glass microspheres containing 3.7 GBq of 186Re and 8.5 GBq of 188Re could be used to deliver a 100 Gy dose to a cancerous tumor, while limiting the total body dose caused by rhenium dissolution to approximately 1 mGy.

  18. Zirconia solubility in boroaluminosilicate glass

    SciTech Connect

    Raman, S.V.; Bopp, R.; Batcheller, T.A.; Yan, Q.

    1995-12-31

    In the Idaho Chemical Processing Plant (ICPP) waste streams, zirconia is often the waste load limiting species. It modifies the glass network, enhances durability, increases viscosity and induces crystallization. The limits of its dissolution in boroaluminosilicate glass, with magnesia and soda additions were experimentally determined. A ternary compositional surface is evolved to present the isothermal regimes of liquid, liquid + zircon, liquid + forsterite, and liquid phase sintered ceramic. The potential of partitioning the transuranics, transition elements and solutes in these regimes is discussed. The visible Raman spectroscopic results are presented to elucidate the dependence among glass composition, structure and chemical durability.

  19. Zirconia solubility in boroaluminosilicate glass

    SciTech Connect

    Raman, S.V.; Bopp, R.; Batcheller, T.A.; Yan, Q.

    1996-08-01

    In the Idaho Chemical Processing Plant (ICPP) waste streams, zirconia is often the waste load limiting species. It modifies the glass network, enhances durability, increases viscosity and induces crystallization. The limits of its dissolution in boroaluminosilicate glass, with magnesia and soda additions were experimentally determined. A ternary compositional surface is evolved to present the isothermal regimes of liquid, liquid+zircon, liquid+forsterite, and liquid phase sintered ceramic. The potential of partitioning the transuranics, transition elements and solutes in these regimes is discussed. The visible Raman spectroscopic results are presented to elucidate the dependence among glass composition, structure and chemical durability.

  20. Infrared spectroscopy and hydrogen isotope geochemistry of hydrous silicate glasses. Progress report

    SciTech Connect

    Epstein, S.; Stolper, E.

    1992-03-01

    The focus of this project is the combined appication of infrared spectroscopy and stable isotope geochemistry to the study of hydrogen-bearing species dissolved in silicate melts and glasses. We are conducting laboratory experiments aimed at determining the fractionation of D and H between melt species (OH and H{sub 2}O) and hydrous vapor and the diffusivities of these species in glasses and melts. Knowledge of these parameters is critical to understanding the behavior of hydrogen isotopes during igneous processes and hydrothermal processes. These results also could be valuable in application of glass technology to development of nuclear waste disposal strategies.

  1. Properties Of Soda/Yttria/Silica Glasses

    NASA Technical Reports Server (NTRS)

    Angel, Paul W.; Hann, Raiford E.

    1994-01-01

    Experimental study of glass-formation compositional region of soda/ yttria/silicate system and of selected physical properties of glasses within compositional region part of continuing effort to identify glasses with high coefficients of thermal expansion and high softening temperatures, for use as coatings on superalloys and as glass-to-metal seals.

  2. Apollo applications of beta fiber glass

    NASA Technical Reports Server (NTRS)

    Naimer, J.

    1971-01-01

    The physical characteristics of Beta fiber glass are discussed. The application of Beta fiber glass for fireproofing the interior of spacecraft compartments is described. Tests to determine the flammability of Beta fiber glass are presented. The application of Beta fiber glass for commercial purposes is examined.

  3. Containerless Manufacture of Glass Optical Fibers

    NASA Technical Reports Server (NTRS)

    Naumann, R. J.; Ethridge, E. C.

    1985-01-01

    Contamination and crystallization reduced in proposed process. Solid optical fiber drawn from an acoustically levitated lump of molten glass. New material added in solid form, melted and then moved into main body of molten glass. Single axis acoustic levitation furnances levitate glass melts at temperature up to about 700 degrees C. Processing in unit limited to low-melting temperature glasses.

  4. 7 CFR 2902.30 - Glass cleaners.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Glass cleaners. 2902.30 Section 2902.30 Agriculture... Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass... qualifying biobased glass cleaners. By that date, Federal agencies that have the responsibility for...

  5. 7 CFR 2902.30 - Glass cleaners.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Glass cleaners. 2902.30 Section 2902.30 Agriculture... Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass... qualifying biobased glass cleaners. By that date, Federal agencies that have the responsibility for...

  6. Galactic Hearts of Glass

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Click on image for larger graph

    This artist's concept shows delicate greenish crystals sprinkled throughout the violent core of a pair of colliding galaxies. The white spots represent a thriving population of stars of all sizes and ages. NASA's Spitzer Space Telescope detected more than 20 bright and dusty galactic mergers like the one depicted here, all teeming with the tiny gem-like crystals.

    When galaxies collide, they trigger the birth of large numbers of massive stars. Astronomers believe these blazing hot stars act like furnaces to produce silicate crystals in the same way that glass is made from sand. The stars probably shed the crystals as they age, and as they blow apart in supernovae explosions.

    At the same time the crystals are being churned out, they are also being destroyed. Fast-moving particles from supernova blasts easily convert silicates crystals back to their amorphous, or shapeless, form.

    How is Spitzer seeing the crystals if they are rapidly disappearing? Astronomers say that, for a short period of time at the beginning of galactic mergers, massive stars might be producing silicate crystals faster than they are eliminating them. When our own galaxy merges with the Andromeda galaxy in a few billion years, a similar burst of massive stars and silicate crystals might occur.

    Crystal Storm in Distant Galaxy The graph (see inset above) of infrared data from NASA's Spitzer Space Telescope tells astronomers that a distant galaxy called IRAS 08752+3915 is experiencing a storm of tiny crystals made up of silicates. The crystals are similar to the glass-like grains of sand found on Earth's many beaches.

    The data were taken by Spitzer's infrared spectrograph, which splits light open to reveal its rainbow-like components. The resulting spectrum shown here reveals the signatures of both crystalline (green) and non-crystalline (brown) silicates.

    Spitzer detected the same crystals in 20 additional galaxies, all belonging to a class called ultraluminous infrared galaxies. These extremely bright and dusty galaxies usually consist of two galaxies in the process of smashing into each other. Astronomers believe massive stars at the hearts of the galaxies are churning out clouds of silicate crystals. This phenomenon may represent a short-lived phase in the evolution of galactic mergers.

  7. Reinforced glass beamsReinforced glass beamsg Auteur Dr. Christian LOUTER 1

    E-print Network

    Lenstra, Arjen K.

    Reinforced glass beamsReinforced glass beamsg EDCE Auteur Dr. Christian LOUTER 1 ENAC/EDCE 2011In contemporary architecture glass is increasinglyIn contemporary architecture glass is increasingly applied for structural components such as beamsapplied for structural components such as beams. However glass

  8. ALICE THROUGH LOOKING GLASS AFTER LOOKING GLASS: THE MATHEMATICS OF MIRRORS AND KALEIDOSCOPES

    E-print Network

    Goodman, Roe

    ALICE THROUGH LOOKING GLASS AFTER LOOKING GLASS: THE MATHEMATICS OF MIRRORS AND KALEIDOSCOPES ROE enough to write a third Alice book called Alice Through Looking Glass After Looking Glass. The book opens with Alice in her chamber in front of several looking glasses. She enters one of them and discovers that she

  9. Tailoring Silicon Oxycarbide Glasses for Oxidative Stability

    NASA Technical Reports Server (NTRS)

    Hurwitz, F. I.; Meador, M. A. B.

    1997-01-01

    Blackglas(Trademark) polysiloxane systems produce silicon oxycarbide glasses by pyrolysis in inert atmosphere. The silicon oxycarbides evidence oxidative degradation that limits their lifetime as composite matrices. The present study characterizes bonding rearrangements in the oxycarbide network accompanying increases in pyrolysis temperature. It also addresses the changes in susceptibility to oxidation due to variations in the distribution of Si bonded species obtained under different processing conditions. The study is carried out using Si-29 nuclear magnetic resonance (NMR) spectroscopy and a design of experiments approach to model the oxidation behavior. The NMR results are compared with those obtained by thermogravimetric analysis (TGA). Samples pyrolyzed under inert conditions are compared to those pyrolyzed in reactive ammonia environments.

  10. Glass-formers vs. Assemblers

    NASA Astrophysics Data System (ADS)

    Glotzer, Sharon

    2015-03-01

    In most instances, the formation of a glass signifies an inability of the constituents of a system to self-organize into a well-defined, thermodynamically preferred ordered structure. Thus good ''assemblers'' may make poor glass-formers, and good glass-formers tend to be poor assemblers. How good or bad a system is in assembling or vitrifying/jamming depends on many features of the constituent building blocks, including shape and interactions. In many cases, building blocks whose shapes make them good glass-formers can, through almost imperceptible perturbations, become good assemblers, and vice versa. We examine these issues through consideration of several model systems, including colloidal ''rocks'' and foldable nets. *with E.R. Chen, P. Damasceno, P. Dodd, M. Engel, A.S. Keys, D. Klotsa, E. Teich, and G. van Anders

  11. Fiber glass pulling. [in space

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.

    1987-01-01

    Experiments were conducted to determine the viability of performing containerless glass fiber pulling in space. The optical transmission properties and glass-forming capabilities of the heavy metal fluorides are reviewed and the acoustic characteristics required for a molten glass levitation system are examined. The design limitations of, and necessary modifications to the acoustic levitation furnace used in the experiments are discussed in detail. Acoustic levitator force measurements were performed and a thermal map of the furnace was generated from thermocouple data. It was determined that the thermal capability of the furnace was inadequate to melt a glass sample in the center. The substitution of a 10 KW carbon monoxide laser for the original furnace heating elements resulted in improved melt heating.

  12. Fast Crystals and Strong Glasses

    SciTech Connect

    Weitz, David

    2009-11-04

    This talk describes new results on model colloid systems that provide insight into the behavior of fundamental problems in colloid physics, and more generally, for other materials as well. By visualizing the nucleation and growth of colloid crystals, we find that the incipient crystallites are much more disordered than expected, leading to a larger diversity of crystal morphologies. When the entropic contribution of these diverse morphologies is included in the free energy, we are able to describe the behavior very well, and can predict the nucleation rate surprisingly accurately. The talk also describes the glass transition in deformable colloidal particles, and will show that when the internal elasticity of the particles is included, the colloidal glass transition mimics that of molecular glass formers much more completely. These results also suggest that the elasticity at the scale of the fundamental unit, either colloid particle or molecule, determines the nature of the glass transition, as described by the "fragility."

  13. High Tech Art: Chameleon Glass

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Dichroic Glass is a technology wherein extremely thin films of metal are vacuum deposited on a glass surface. The coated glass shields spacecraft instruments from cosmic radiation and protects human vision from unfiltered sunlight in space. Because the coating process allows some wavelengths of light and color to reflect and others to pass through, a chameleon effect is produced. Murray Schwartz, a former aerospace engineer, has based his business KROMA on this NASA optical technology. He produces dichroic stained glass windows, mobiles and jewelry. The technique involves deposition of super thin layers of metal oxides applied one layer at a time in a specific order and thickness for the desired effect. His product line is unique and has been very successful.

  14. Glass Furnace Model Version 2

    Energy Science and Technology Software Center (ESTSC)

    2003-05-06

    GFM2.0 is a derivative of the GFM code with substantially altered and enhanced capabilities. Like its predecessor, it is a fully three-dimensional, furnace simulation model that provides a more accurate representation of the entire furnace, and specifically, the glass melting process, by coupling the combustion space directly to the glass batch and glass melt via rigorous radiation heat transport models for both the combustion space and the glass melt. No assumptions are made with regardmore »to interfacial parameters of heat, flux, temperature distribution, and batch coverage as must be done using other applicable codes available. These critical parameters are calculated. GFM2.0 contains a processor structured to facilitate use of the code, including the entry of teh furnace geometry and operating conditions, the execution of the program, and display of the computational results. Furnace simulations can therefore be created in a straightforward manner.« less

  15. Stereo Compilation (3D) Glasses

    USGS Multimedia Gallery

    Manufactured by the Bausch and Lomb Optical Company. Stereographs and stereo compilation glasses are used in the photogrammetry, which is the process of making maps or scale drawings from photographs, especially aerial photographs. Object ID: USGS-000276...

  16. Comparison of Macedon and Darwin glass

    USGS Publications Warehouse

    Chapman, D.R.; Keil, Klaus; Annell, C.

    1967-01-01

    Chemical analyses are presented for major and minor elements in two specimens of natural glass reported from Macedon, Victoria, and are compared with new analyses of glass from Mt. Darwin, Tasmania. One specimen of Macedon glass is dark, the other light; both are spongy with relatively large cavities of size uncommon in Darwin glass. Some of the new analyses of Darwin glass extend considerably the compositional range previously reported for Mg, Ni and Co. The chemical composition of Macedon glass cannot be distinguished from that of Darwin glass for any of twenty-five elements investigated. It appears possible that the two specimens of glass reported from Macedon may represent either two mislabelled pieces of Darwin glass, or else a separate natural occurrence of Darwin glass 560 km north of Mt. Darwin. ?? 1967.

  17. Luminescence of powdered uranium glasses

    NASA Technical Reports Server (NTRS)

    Eubanks, A. G.; Mcgarrity, J. M.; Silverman, J.

    1974-01-01

    Measurement of cathodoluminescence and photoluminescence efficiencies in powdered borosilicate glasses having different particle size and different uranium content. Excitation with 100 to 350 keV electrons and with 253.7 nm light was found to produce identical absolute radiant exitance spectra in powdered samples. The most efficient glass was one containing 29.4 wt% B2O3, 58.8 wt% SiO2, 9.8 wt% Na2O and 2.0 wt% UO2.

  18. Driving bubbles out of glass

    NASA Technical Reports Server (NTRS)

    Mattox, D. M.

    1981-01-01

    Surface tension gradient in melt forces gas bubbles to surface, increasing glass strength and transparency. Conventional chemical and buoyant fining are extremely slow in viscous glasses, but tension gradient method moves 250 um bubbles as rapidly as 30 um/s. Heat required for high temperature part of melt is furnished by stationary electrical or natural-gas heater; induction and laser heating are also possible. Method has many applications in industry processes.

  19. Fabrication of glass microspheres with conducting surfaces

    DOEpatents

    Elsholz, W.E.

    1982-09-30

    A method for making hollow glass microspheres with conducting surfaces by adding a conducting vapor to a region of the glass fabrication furnace. As droplets or particles of glass forming material pass through multiple zones of different temperature in a glass fabrication furnace, and are transformed into hollow glass microspheres, the microspheres pass through a region of conducting vapor, forming a conducting coating on the surface of the microspheres.

  20. Fabrication of glass microspheres with conducting surfaces

    DOEpatents

    Elsholz, William E. (Acampo, CA)

    1984-01-01

    A method for making hollow glass microspheres with conducting surfaces by adding a conducting vapor to a region of the glass fabrication furnace. As droplets or particles of glass forming material pass through multiple zones of different temperature in a glass fabrication furnace, and are transformed into hollow glass microspheres, the microspheres pass through a region of conducting vapor, forming a conducting coating on the surface of the microspheres.

  1. Glass Membrane For Controlled Diffusion Of Gases

    DOEpatents

    Shelby, James E. (Alfred Station, NY); Kenyon, Brian E. (Pittsburgh, PA)

    2001-05-15

    A glass structure for controlled permeability of gases includes a glass vessel. The glass vessel has walls and a hollow center for receiving a gas. The glass vessel contains a metal oxide dopant formed with at least one metal selected from the group consisting of transition metals and rare earth metals for controlling diffusion of the gas through the walls of the glass vessel. The vessel releases the gas through its walls upon exposure to a radiation source.

  2. Metallic Glass Cooling

    NASA Technical Reports Server (NTRS)

    2003-01-01

    A sample of advanced metallic glass alloy cools down during an experiment with the TEMPUS furnace on STS-94, July 7, 1997, MET:5/23:35 (approximate). The sequence shows the sample glowing, then fading to black as scientists began the process of preserving the liquid state, but lowering the temperature below the normal solidification temperature of the alloy. This process is known as undercooling. (10 second clip covering approximately 50 seconds.) TEMPUS (stands for Tiegelfreies Elektromagnetisches Prozessiere unter Schwerelosigkeit (containerless electromagnetic processing under weightlessness). It was developed by the German Space Agency (DARA) for flight aboard Spacelab. The DARA project scientist was Igon Egry. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). DARA and NASA are exploring the possibility of flying an advanced version of TEMPUS on the International Space Station. (354KB JPEG, 2700 x 2038 pixels; downlinked video, higher quality not available) The MPG from which this composite was made is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300189.html.

  3. Glasses-free randot stereotest.

    PubMed

    Kim, Jonghyun; Hong, Jong-Young; Hong, Keehoon; Yang, Hee Kyung; Han, Sang Beom; Hwang, Jeong-Min; Lee, Byoungho

    2015-06-01

    We proposed a glasses-free randot stereotest using a multiview display system. We designed a four-view parallax barrier system and proposed the use of a random-dot multigram as a set of view images for the glasses-free randot stereotest. The glasses-free randot stereotest can be used to verify the effect of glasses in a stereopsis experience. Furthermore, the proposed system is convertible between two-view and four-view structures so that the motion parallax effect could be verified within the system. We discussed the design principles and the method used to generate images in detail and implemented a glasses-free randot stereotest system with a liquid crystal display panel and a customized parallax barrier. We also developed graphical user interfaces and a method for their calibration for practical usage. We performed experiments with five adult subjects with normal vision. The experimental results show that the proposed system provides a stereopsis experience to the subjects and is consistent with the glasses-type randot stereotest and the Frisby–Davis test. The implemented system is free from monocular cues and provides binocular disparity only. The crosstalk of the system is about 6.42% for four-view and 4.17% for two-view, the time required for one measurement is less than 20 s, and the minimum angular disparity that the system can provide is about 23 arc sec. PMID:26057031

  4. BNFL Report Glass Formers Characterization

    SciTech Connect

    Schumacher, R.F.

    2000-07-27

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. The problems might include arching or ratholing in the silo/hopper. In addition, all of the blends may require consideration for their handling.

  5. BNFL Report Glass Formers Characterization

    SciTech Connect

    Schumacher, R.F.

    2000-07-27

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. In addition, all of the blends may require consideration for their handling. A number of engineering considerations and recommendations were prepared based on the experimental findings, experience, and other process considerations. Recommendations for future testing are included. In conjunction with future work, it is recommended that a professional consultant be engaged to guide and assist with testing and design input.

  6. Bioactive Glasses: Frontiers and Challenges.

    PubMed

    Hench, Larry L; Jones, Julian R

    2015-01-01

    Bioactive glasses were discovered in 1969 and provided for the first time an alternative to nearly inert implant materials. Bioglass formed a rapid, strong, and stable bond with host tissues. This article examines the frontiers of research crossed to achieve clinical use of bioactive glasses and glass-ceramics. In the 1980s, it was discovered that bioactive glasses could be used in particulate form to stimulate osteogenesis, which thereby led to the concept of regeneration of tissues. Later, it was discovered that the dissolution ions from the glasses behaved like growth factors, providing signals to the cells. This article summarizes the frontiers of knowledge crossed during four eras of development of bioactive glasses that have led from concept of bioactivity to widespread clinical and commercial use, with emphasis on the first composition, 45S5 Bioglass(®). The four eras are (a) discovery, (b) clinical application, (c) tissue regeneration, and (d) innovation. Questions still to be answered for the fourth era are included to stimulate innovation in the field and exploration of new frontiers that can be the basis for a general theory of bioactive stimulation of regeneration of tissues and application to numerous clinical needs. PMID:26649290

  7. Bioactive Glasses: Frontiers and Challenges

    PubMed Central

    Hench, Larry L.; Jones, Julian R.

    2015-01-01

    Bioactive glasses were discovered in 1969 and provided for the first time an alternative to nearly inert implant materials. Bioglass formed a rapid, strong, and stable bond with host tissues. This article examines the frontiers of research crossed to achieve clinical use of bioactive glasses and glass–ceramics. In the 1980s, it was discovered that bioactive glasses could be used in particulate form to stimulate osteogenesis, which thereby led to the concept of regeneration of tissues. Later, it was discovered that the dissolution ions from the glasses behaved like growth factors, providing signals to the cells. This article summarizes the frontiers of knowledge crossed during four eras of development of bioactive glasses that have led from concept of bioactivity to widespread clinical and commercial use, with emphasis on the first composition, 45S5 Bioglass®. The four eras are (a) discovery, (b) clinical application, (c) tissue regeneration, and (d) innovation. Questions still to be answered for the fourth era are included to stimulate innovation in the field and exploration of new frontiers that can be the basis for a general theory of bioactive stimulation of regeneration of tissues and application to numerous clinical needs. PMID:26649290

  8. Space processing of chalcogenide glass

    NASA Technical Reports Server (NTRS)

    Ali, M. A.; Larsen, D. C.

    1976-01-01

    The manner in which the weightless, containerless nature of in-space processing can be successfully utilized to improve the quality of infrared transmitting chalcogenide glasses was investigated. The following conclusions were reached: (1) Laboratory experiments have established the techniques, processes and equipment necessary for the production of high purity chalcogenide glasses. (2) Processing techniques have been successfully adopted for Ge28Sb12Se60 glass in a 1-g environment. (3) The Ge28Sb12Se60 glasses that have been processed have optical transmission around 63% (5 mm thick). (4) Laboratory experiments have established that the use of precursor materials in powdered form increases the oxygen contamination of the processed glass. This indicates that high purity precursor materials in bar or pellet form should be used. (5) Modifications were made on the MSFC acoustic levitator in an attempt to improve levitation stability during long-time experiments. Room temperature experiments on As2S3 glasses and high temperature experiments on polystyrene were conducted.

  9. Glasses-free randot stereotest

    NASA Astrophysics Data System (ADS)

    Kim, Jonghyun; Hong, Jong-Young; Hong, Keehoon; Yang, Hee Kyung; Han, Sang Beom; Hwang, Jeong-Min; Lee, Byoungho

    2015-06-01

    We proposed a glasses-free randot stereotest using a multiview display system. We designed a four-view parallax barrier system and proposed the use of a random-dot multigram as a set of view images for the glasses-free randot stereotest. The glasses-free randot stereotest can be used to verify the effect of glasses in a stereopsis experience. Furthermore, the proposed system is convertible between two-view and four-view structures so that the motion parallax effect could be verified within the system. We discussed the design principles and the method used to generate images in detail and implemented a glasses-free randot stereotest system with a liquid crystal display panel and a customized parallax barrier. We also developed graphical user interfaces and a method for their calibration for practical usage. We performed experiments with five adult subjects with normal vision. The experimental results show that the proposed system provides a stereopsis experience to the subjects and is consistent with the glasses-type randot stereotest and the Frisby-Davis test. The implemented system is free from monocular cues and provides binocular disparity only. The crosstalk of the system is about 6.42% for four-view and 4.17% for two-view, the time required for one measurement is less than 20 s, and the minimum angular disparity that the system can provide is about 23 arc sec.

  10. HIGH-LEVEL WASTE GLASS FORMULATION MODEL SENSITIVITY STUDY 2009 GLASS FORMULATION MODEL VERSUS 1996 GLASS FORMULATION MODEL

    SciTech Connect

    BELSHER JD; MEINERT FL

    2009-12-07

    This document presents the differences between two HLW glass formulation models (GFM): The 1996 GFM and 2009 GFM. A glass formulation model is a collection of glass property correlations and associated limits, as well as model validity and solubility constraints; it uses the pretreated HLW feed composition to predict the amount and composition of glass forming additives necessary to produce acceptable HLW glass. The 2009 GFM presented in this report was constructed as a nonlinear optimization calculation based on updated glass property data and solubility limits described in PNNL-18501 (2009). Key mission drivers such as the total mass of HLW glass and waste oxide loading are compared between the two glass formulation models. In addition, a sensitivity study was performed within the 2009 GFM to determine the effect of relaxing various constraints on the predicted mass of the HLW glass.

  11. Introduction and Motivation Structural Model for Laminated Glass Beams Conclusions and Outlook of Laminated Glass Structures

    E-print Network

    Introduction and Motivation Structural Model for Laminated Glass Beams Conclusions and Outlook 1 #12;Introduction and Motivation Structural Model for Laminated Glass Beams Conclusions and Outlook Outline 1 Introduction and Motivation 2 Structural Model for Laminated Glass Beams 3 Conclusions

  12. Risks of nuclear fuel reprocessing

    SciTech Connect

    Durant, W.S.

    1990-01-01

    The Savannah River Site's primary function is the production of weapons materials. It consists of four reactors, two fuel reprocessing facilities, a fuel fabrication facility, a nuclear fuel facility for the Navy and a heavy water recycle facility. Under construction is a facility to convert the site's liquid wastes into borosilicate glass. The topic of this paper is risks of nuclear fuel reprocessing. Also discussed are facility operations. 18 figs.

  13. Spheroidization of glass powders for glass ionomer cements.

    PubMed

    Gu, Y W; Yap, A U J; Cheang, P; Kumar, R

    2004-08-01

    Commercial angular glass powders were spheroidized using both the flame spraying and inductively coupled radio frequency plasma spraying techniques. Spherical powders with different particle size distributions were obtained after spheroidization. The effects of spherical glass powders on the mechanical properties of glass ionomer cements (GICs) were investigated. Results showed that the particle size distribution of the glass powders had a significant influence on the mechanical properties of GICs. Powders with a bimodal particle size distribution ensured a high packing density of glass ionomer cements, giving relatively high mechanical properties of GICs. GICs prepared by flame-spheroidized powders showed low strength values due to the loss of fine particles during flame spraying, leading to a low packing density and few metal ions reacting with polyacrylic acid to form cross-linking. GICs prepared by the nano-sized powders showed low strength because of the low bulk density of the nano-sized powders and hence low powder/liquid ratio of GICs. PMID:15046893

  14. A Cosmic Magnifying Glass

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Scanning the heavens for the first time since the successful December 1999 servicing mission, NASA's Hubble Space Telescope imaged a giant, cosmic magnifying glass, a massive cluster of galaxies called Abell 2218. This 'hefty' cluster resides in the constellation Draco, some 2 billion light-years from Earth. The cluster is so massive that its enormous gravitational field deflects light rays passing through it, much as an optical lens bends light to form an image. This phenomenon, called gravitational lensing, magnifies, brightens, and distorts images from faraway objects. The cluster's magnifying powers provides a powerful 'zoom lens' for viewing distant galaxies that could not normally be observed with the largest telescopes. The picture is dominated by spiral and elliptical galaxies. Resembling a string of tree lights, the biggest and brightest galaxies are members of the foreground cluster. Researchers are intrigued by a tiny red dot just left of top center. This dot may be an extremely remote object made visible by the cluster's magnifying powers. Further investigation is needed to confirm the object's identity. The color picture already reveals several arc-shaped features that are embedded in the cluster and cannot be easily seen in the black-and- white image. The colors in this picture yield clues to the ages, distances, and temperatures of stars, the stuff of galaxies. Blue pinpoints hot young stars. The yellow-white color of several of the galaxies represents the combined light of many stars. Red identifies cool stars, old stars, and the glow of stars in distant galaxies. This view is only possible by combining Hubble's unique image quality with the rare lensing effect provided by the magnifying cluster.

  15. Fabrication and characterization of MCC (Materials Characterization Center) approved testing material: ATM-10 glass

    SciTech Connect

    Maupin, G.D.; Bowen, W.M.; Daniel, J.L.

    1988-04-01

    The Materials Characterization Center ATM-10 glass represents a reference commercial high-level waste form similar to that which will be produced by the West Valley Nuclear Service Co. Inc., West Valley, New York. The target composition and acceptable range of composition were defined by the sponsor, West Valley Nuclear Service. The ATM-10 glass was produced in accordance with the Pacific Northwest Laboratory QA Manual for License-Related Programs, MCC technical procedures, and MCC QA Plan that were in effect during the course of the work. The method and procedure to be used in the fabrication and characterization of the ATM-10 glass were specified in two run plans for glass preparation and a characterization plan. All of the ATM-10 glass was produced in the form of bars 1.9 /times/ 1.9 /times/ 10 cm nominal size, and 93 g nominal mass. A total of 15 bars of ATM-10 glass weighing 1394 g was produced. The production bars were characterized to determine the mean composition, oxidation state, and microstructure of the ATM-10 product. Table A summarizes the characterization results. The ATM-10 glass meets all specifications. The elemental composition and oxidation state of the glass are within the specifications of the client. Visually, the ATM-10 glass bars appear uniformly glassy and generally without exterior features. Microscopic examination revealed low (less than 2 wt %) concentractions of 3-..mu..m iron-chrome (suspected spinel) crystals and /approximately/0.5-..mu..m ruthenium inclusions scattered randomly throughout the glassy matrix. Closed porosity, with pores ranging in diameter from 5 to 250 ..mu..m, was observed in all samples. 4 refs., 10 figs., 21 tabs.

  16. Power laser application for security glass production

    NASA Astrophysics Data System (ADS)

    Abashkin, Vladimir; Achimova, Elena

    2009-09-01

    Modern glass application needs to move from traditional tempering with only average controlled fragmentation of security glass to computerized controlled fragmentation by developing engineered stress profiles in glass article. The new treatment methods of soda-lime float glass using irradiation by power Nd:YAG laser which is moved by robot will be discussed. The transparency of glass for laser wavelength is one of the problems of glass treatment by laser. Noncontact stress control by light scattering will be shown. The two main objectives of this work will be discussed: 1. Glass treatment by power laser beam directed to secure glass production; 2. Control methods of residual stress into float glasses treated by laser.

  17. Power laser application for security glass production

    NASA Astrophysics Data System (ADS)

    Abashkin, Vladimir; Achimova, Elena

    2010-05-01

    Modern glass application needs to move from traditional tempering with only average controlled fragmentation of security glass to computerized controlled fragmentation by developing engineered stress profiles in glass article. The new treatment methods of soda-lime float glass using irradiation by power Nd:YAG laser which is moved by robot will be discussed. The transparency of glass for laser wavelength is one of the problems of glass treatment by laser. Noncontact stress control by light scattering will be shown. The two main objectives of this work will be discussed: 1. Glass treatment by power laser beam directed to secure glass production; 2. Control methods of residual stress into float glasses treated by laser.

  18. Investigation of Glass Transition Temperature of Binary Tellurite Glasses

    SciTech Connect

    Chippy, L.; Unnithan, C. Harikuttan; Jayakumar, S.

    2011-10-20

    Five series of binary Tellurite glass samples containing Sb{sub 2}O{sub 4}, WO{sub 3}, Fe{sub 2}O{sub 3}, Na{sub 2}O and ZnO{sub 2} are studied in terms of the variation of glass transition temperature (T{sub g}). It is seen that Tg increases as Tellurite concentration decreases in the case of glasses containing metal oxides Sb{sub 2}O{sub 4} WO{sub 3}, and Fe{sub 2}O{sub 3} while T{sub g} shows a decreasing trend with that of Na{sub 2}O and ZnO and the corresponding changes in the network structure are accounted to possible extent. The structural variations are analyzed using the concept of electronegativity.

  19. The formation of crystals in glasses containing rare earth oxides

    SciTech Connect

    Fadzil, Syazwani Mohd; Hrma, Pavel; Crum, Jarrod; Siong, Khoo Kok; Ngatiman, Mohammad Fadzlee; Said, Riduan Mt

    2014-02-12

    Korean spent nuclear fuel will reach the capacity of the available temporary storage by 2016. Pyroprocessing and direct disposal seems to be an alternative way to manage and reuse spent nuclear fuel while avoiding the wet reprocessing technology. Pyroprocessing produces several wastes streams, including metals, salts, and rare earths, which must be converted into stabilized form. A suitable form for rare earth immobilization is borosilicate glass. The borosilicate glass form exhibits excellent durability, allows a high waste loading, and is easy to process. In this work, we combined the rare earths waste of composition (in wt%) 39.2Nd{sub 2}O{sub 3}–22.7CeO{sub 2}–11.7La{sub 2}O{sub 3}–10.9PrO{sub 2}–1.3Eu{sub 2}O{sub 3}–1.3Gd{sub 2}O{sub 3}–8.1Sm{sub 2}O{sub 3}–4.8Y{sub 2}O{sub 3} with a baseline glass of composition 60.2SiO{sub 2}–16.0B{sub 2}O{sub 3}–12.6Na{sub 2}O–3.8Al{sub 2}O{sub 3}–5.7CaO–1.7ZrO{sub 2}. Crystallization in waste glasses occurs as the waste loading increases. It may produce complicate glass processing and affect the product quality. To study crystal formation, we initially made glasses containing 5%, 10% and 15% of La{sub 2}O{sub 3} and then glasses with 5%, 10% and 15% of the complete rare earth mix. Samples were heat-treated for 24 hours at temperatures 800°C to 1150°C in 50°C increments. Quenched samples were analyzed using an optical microscope, scanning electron microscope with energy dispersive spectroscopy, and x-ray diffraction. Stillwellite (LaBSiO{sub 5}) and oxyapatite (Ca{sub 2}La{sub 8}Si{sub 6}O{sub 26}) were found in glasses containing La{sub 2}O{sub 3}, while oxyapatite (Ca{sub 2}La{sub 8}Si{sub 6}O{sub 26} and NaNd{sub 9}Si{sub 6}O{sub 26}) precipitated in glasses with additions of mixed rare earths. The liquidus temperature (T{sub L}) of the glasses containing 5%, 10% and 15% La{sub 2}O{sub 3} were 800°C, 959°C and 986°C, respectively; while T{sub L} was 825°C, 1059°C and 1267°C for glasses with 5%, 10% and 15% addition of mixed rare earth oxides. The component coefficients T{sub B2O3}, T{sub SiO2}, T{sub CaO}, and T{sub RE2O3} were also evaluated using a recently published study.

  20. Iron phosphate glass for immobilization of 99Tc

    SciTech Connect

    Xu, Kai; Hrma, Pavel R.; Um, Wooyong; Heo, Jong

    2013-06-15

    Technetium-99 (99Tc) can bring serious environmental threats because of its long half-life (t1/2 = ~2.1 x 105 years), high fission yield (~6%), and high solubility and mobility in the ground water. The high volatility makes it difficult to immobilize 99Tc in continuous melters vitrifying 99Tc-containing nuclear wastes in borosilicate glasses. This work explores a possibility of incorporating a high concentration of 99Tc, surrogated by the non-radioactive Re, in an iron phosphate glass by melting mixtures of iron phosphate glass frits with 1.5-6 mass% KReO4 at ~1000 C. The retention of Re achieved was ~1.1 mass%. The normalized Re release by the 7-day Product Consistency Test was <10*2 g/m2. Surprisingly, the Re escaped from the melt within a short time of heating, especially when the temperature was increased. Therefore, 99Tc volatilization would still be a challenging task for its immobilization in iron phosphate glasses.

  1. Iron phosphate glass for immobilization of 99Tc

    NASA Astrophysics Data System (ADS)

    Xu, Kai; Hrma, Pavel; Um, Wooyong; Heo, Jong

    2013-10-01

    Technetium-99 (99Tc) can bring serious environmental threats because of its long half-life (?1/2 = ?2.1 × 105 years), high fission yield (?6%), and high solubility and mobility in the ground water. The high volatility makes it difficult to immobilize 99Tc in continuous melters vitrifying 99Tc-containing nuclear wastes in borosilicate glasses. This work explores a possibility of incorporating a high concentration of 99Tc, surrogated by the non-radioactive Re, in an iron phosphate glass by melting mixtures of iron phosphate glass frits with 1.5-6 mass% KReO4 at ?1000 °C. The retention of Re achieved was ?1.1 mass%. The normalized Re release by the 7-day Product Consistency Test was <10-2 g/m2. Surprisingly, the Re escaped from the melt within a short time of heating, especially when the temperature was increased. Therefore, 99Tc volatilization would still be a challenging task for its immobilization in iron phosphate glasses.

  2. Mechanisms of Rhyolitic Glass Hydration Below the Glass Transition

    SciTech Connect

    Anovitz, Lawrence {Larry} M; Cole, David R; Fayek, Mostafa

    2008-01-01

    Although a great deal is known about the interaction between water and rhyolitic glasses and melts at temperatures above the glass transition, the nature of this interaction at lower temperatures is much more obscure. Comparisons between high- and low-temperature diffusion studies suggest that several factors play important roles under lower-temperature conditions that are not significant at higher temperatures. Water concentrations in rhyolitic glasses hydrated at low temperatures are significantly greater than in those hydrated at high temperatures and low pressures. Surface concentrations, which equilibrate quickly with the surrounding environment at high temperature, change far more slowly as temperature decreases, and may not equilibrate at room temperature for hundreds or thousands of years. Temperature extrapolations of high- and low-temperature diffusion data are not consistent, suggesting that a change in mechanism occurs. These differences may be due to the inability of "self-stress," caused by the in-diffusing species, to relax at lower temperature. Preliminary calculations suggest that the level of stress caused by glass-water interaction may be greater than the tensile strength of the glass. On a microstuctural scale, extrapolations of high-temperature Fourier transform infrared spectroscopy (FTIR) data to lower temperatures suggests that there should be little or no hydroxyl present in glasses hydrated at low temperature. Comparisons of low-temperature hydration results among SiO2, obsidian, and albite compositions show distinct differences, and features are present in the spectra that do not occur at high temperature. Analysis of H2O and D2O diffusion also suggest that mechanistic differences occur between low- and high-temperature diffusive processes.

  3. Glass matrix composites. I - Graphite fiber reinforced glass

    NASA Technical Reports Server (NTRS)

    Prewo, K. M.; Bacon, J. F.

    1978-01-01

    An experimental program is described in which graphite fibers of Hercules HMS and HTS, Thornel 300, and Celanese DG-12 were used to reinforce, both uniaxially and biaxially, borosilicate pyrex glass. Composite flexural strength distribution, strength as a function of test temperature, fracture toughness and oxidative stability were determined and shown to be primarily a function of fiber type and the quality of fiber-matrix bond formed during composite fabrication. It is demonstrated that the graphite fiber reinforced glass system offers unique possibilities as a high performance structural material.

  4. HLW Glass Studies: Development of Crystal-Tolerant HLW Glasses

    SciTech Connect

    Matyas, Josef; Huckleberry, Adam R.; Rodriguez, Carmen P.; Lang, Jesse B.; Owen, Antionette T.; Kruger, Albert A.

    2012-04-02

    In our study, a series of lab-scale crucible tests were performed on designed glasses of different compositions to further investigate and simulate the effect of Cr, Ni, Fe, Al, Li, and RuO2 on the accumulation rate of spinel crystals in the glass discharge riser of the HLW melter. The experimental data were used to expand the compositional region covered by an empirical model developed previously (Matyáš et al. 2010b), improving its predictive performance. We also investigated the mechanism for agglomeration of particles and impact of agglomerates on accumulation rate. In addition, the TL was measured as a function of temperature and composition.

  5. Electrical conduction and glass relaxation in alkali- silicate glasses

    NASA Astrophysics Data System (ADS)

    Angel, Paul William

    Electrical response measurements from 1 Hz to 1 MHz between 50o and 540oC were made on potassium, sodium and lithium-silicate glasses with low alkali oxide contents. Conductivity and electrical relaxation responses for both annealed and air quenched glasses of the same composition were compared. Quenching was found to lower the dc conductivity, ?dc, and activation energy as well as increase the pre-exponential term when compared to the corresponding annealed glass of the same composition. All of the glasses exhibited Arrhenius behavior in the log ?dc against 1/T plots. A sharp decrease in ?dc was observed for glasses containing alkali concentrations of 7 mol% or less. The ?dc activation energy exhibited similar behavior when plotted as a function of alkali composition and was explained in terms of a mixture of the weak and strong electrolyte models. The depression angle for fits to the complex impedance data were also measured as a function of thermal history, alkali concentration and alkali species. These results were interpreted in terms of changes in the distribution of relaxation times. Annealed samples from a single melt of a 10 mol% K2O-90SiO2 glass were reheated to temperatures ranging from 450o to 800oC, held isothermally for 20 min, and then quenched in either air or silicon oil. The complex impedance of both an annealed and the quenched samples were then measured as a function of temperature from 120o to 250oC. The ?dc was found to be remain unaffected by heat treatments below 450oC, to increase rapidly over an approximate 200oC range of temperatures that was dependent on cooling rate and to be constant for heat treatments above this range. This behavior is interpreted in terms of the mean structural relaxation time as a function of temperature and cooling rate near the glass transition temperature and glass transformation ranges. A more detailed definition for the transition and transformation temperatures and ranges was also provided.

  6. GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSILICATE FRIT B COMPOSITION FOR PLUTONIUM DISPOSITION

    SciTech Connect

    Marra, J

    2006-01-19

    The Department of Energy Office of Environmental Management (DOE/EM) plans to conduct the Plutonium Disposition Project at the Savannah River Site (SRS) to disposition excess weapons-usable plutonium. A plutonium glass waste form is a leading candidate for immobilization of the plutonium for subsequent disposition in a geologic repository. A reference glass composition (Lanthanide Borosilicate (LaBS) Frit B) was developed during the Plutonium Immobilization Program (PIP) to immobilize plutonium. A limited amount of performance testing was performed on this baseline composition before efforts to further pursue Pu disposition via a glass waste form ceased. Therefore, the objectives of this present task were to fabricate plutonium loaded LaBS Frit B glass and perform additional testing to provide near-term data that will increase confidence that LaBS glass product is suitable for disposal in the Yucca Mountain Repository. Specifically, testing was conducted in an effort to provide data to Yucca Mountain Project (YMP) personnel for use in performance assessment calculations. Plutonium containing LaBS glass with the Frit B composition with a 9.5 wt% PuO{sub 2} loading was prepared for testing. Glass was prepared to support Product Consistency Testing (PCT) at Savannah River National Laboratory (SRNL) and for additional performance testing at Argonne National Laboratory (ANL) and Pacific Northwest National Laboratory (PNNL). The glass was characterized using x-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) prior to performance testing. A series of PCTs were conducted at SRNL with varying exposed surface area and test durations. The leachates from these tests were analyzed to determine the dissolved concentrations of key elements. Acid stripping of leach vessels was performed to determine the concentration of the glass constituents that may have sorbed on the vessels during leach testing. Additionally, the leachate solutions were ultrafiltered to quantify colloid formation. The leached solids from select PCTs were examined in an attempt to evaluate the Pu and neutron absorber release behavior from the glass and to identify the formation of alteration phases on the glass surface. Characterization of the glass prior to testing revealed that some undissolved plutonium oxide was present in the glass. The undissolved particles had a disk-like morphology and likely formed via coarsening of particles in areas compositionally enriched in plutonium. Similar disk-like PuO{sub 2} phases were observed in previous LaBS glass testing at PNNL. In that work, researchers concluded that plutonium formed with this morphology as a result of the leaching process. It was more likely that the presence of the plutonium oxide crystals in the PNNL testing was a result of glass fabrication. A series of PCTs were conducted at 90 C in ASTM Type 1 water. The PCT-Method A (PCT-A) was conducted to compare the Pu LaBS Frit B glass durability to current requirements for High Level Waste (HLW) glass in a geologic repository. The PCT-A test has a strict protocol and is designed to specifically be used to evaluate whether the chemical durability and elemental release characteristics of a nuclear waste glass have been consistently controlled during production and, thus, meet the repository acceptance requirements. The PCT-A results on the Pu containing LaBS Frit B glass showed that the glass was very durable with a normalized elemental release value for boron of approximately 0.02 g/L. This boron release value was better than two orders of magnitude better from a boron release standpoint than the current Environmental Assessment (EA) glass used for repository acceptance. The boron release value for EA glass is 16.7 g/L.

  7. Study Of Phase Separation In Glass

    NASA Technical Reports Server (NTRS)

    Neilson, George F.; Weinberg, Michael C.; Smith, Gary L.

    1989-01-01

    Report describes an experimental study of effect of hydroxide content on phase separation in soda/silica glasses. Ordinary and gel glasses melted at 1,565 degree C, and melts stirred periodically. "Wet" glasses produced by passing bubbles of N2 saturated with water through melts; "dry" glasses prepared in similar manner, except N2 dried before passage through melts. Analyses of compositions of glasses performed by atomic-absorption and index-of-refraction measurements. Authors conclude hydroxide speeds up phase separation, regardless of method (gel or ordinary) by which glass prepared. Eventually helps material scientists to find ways to control morphology of phase separation.

  8. Monte Carlo Simulations of the Corrosion of Aluminoborosilicate Glasses

    SciTech Connect

    Kerisit, Sebastien; Ryan, Joseph V; Pierce, Eric M

    2013-01-01

    Aluminum is one of the most common components included in nuclear waste glasses. Therefore, Monte Carlo (MC) simulations were carried out to investigate the influence of aluminum on the rate and mechanism of dissolution of sodium borosilicate glasses in static conditions. The glasses studied were in the compositional range (70 2x)% SiO2x% Al2O3 15% B2O3 (15 + x)% Na2O, where 0 x 15%. The simulation results show that increasing amounts of aluminum in the pristine glasses slow down the initial rate of dissolution as determined from the rate of boron release. However, the extent of corrosion as measured by the total amount of boron release initially increases with addition of Al2O3, up to 5 mol% Al2O3, but subsequently decreases with further Al2O3 addition. The MC simulations reveal that this behavior is due to the interplay between two opposing mechanisms: (1) aluminum slows down the kinetics of hydrolysis/condensation reactions that drive the reorganization of the glass surface and eventual formation of a blocking layer; and (2) aluminum strengthens the glass thereby increasing the lifetime of the upper part of its surface and allowing for more rapid formation of a blocking layer. Additional MC simulations were performed whereby a process representing the formation of a secondary aluminosilicate phase was included. Secondary phase formation draws dissolved glass components out of the aqueous solution, thereby diminishing the rate of condensation and delaying the formation of a blocking layer. As a result, the extent of corrosion is found to increase continuously with increasing Al2O3 content, as observed experimentally. For Al2O3 < 10 mol%, the MC simulations also indicate that, because the secondary phase solubility eventually controls the aluminum content in the part of the altered layer in contact with the bulk aqueous solution, the dissolved aluminum and silicon concentrations at steady state are not dependent on the Al2O3 content of the pristine aluminoborosilicate glass.

  9. Monte Carlo Simulations of the Corrosion of Aluminoborosilicate Glasses

    SciTech Connect

    Kerisit, Sebastien N.; Ryan, Joseph V.; Pierce, Eric M.

    2013-10-15

    Aluminum is one of the most common components included in nuclear waste glasses. Therefore, Monte Carlo (MC) simulations were carried out to investigate the influence of aluminum on the rate and mechanism of dissolution of sodium borosilicate glasses in static conditions. The glasses studied were in the compositional range (70-2x)% SiO2 x% Al2O3 15% B2O3 (15+x)% Na2O, where 0 ? x ? 15%. The simulation results show that increasing amounts of aluminum in the pristine glasses slow down the initial rate of dissolution as determined from the rate of boron release. However, the extent of corrosion - as measured by the total amount of boron release - initially increases with addition of Al2O3, up to 5 Al2O3 mol%, but subsequently decreases with further Al2O3 addition. The MC simulations reveal that this behavior is due to the interplay between two opposing mechanisms: (1) aluminum slows down the kinetics of hydrolysis/condensation reactions that drive the reorganization of the glass surface and eventual formation of a blocking layer; and (2) aluminum strengthens the glass thereby increasing the lifetime of the upper part of its surface and allowing for more rapid formation of a blocking layer. Additional MC simulations were performed whereby a process representing the formation of a secondary aluminosilicate phase was included. Secondary phase formation draws dissolved glass components out of the aqueous solution, thereby diminishing the rate of condensation and delaying the formation of a blocking layer. As a result, the extent of corrosion is found to increase continuously with increasing Al2O3 content, as observed experimentally. For Al2O3 < 10 mol%, the MC simulations also indicate that, because the secondary phase solubility eventually controls the aluminum content in the part of the altered layer in contact with the bulk aqueous solution, the dissolved aluminum and silicon concentrations at steady state are not dependent on the Al2O3 content of the pristine aluminoborosilicate glass.

  10. Preparation and characterization of special glasses for sealing and other applications

    NASA Astrophysics Data System (ADS)

    Shrikhande, V. K.

    2009-07-01

    Glasses find wide applications, among others, in process technologies, vacuum science and technology etc. because of their desired thermo-mechanical properties and chemical durability. In particular, hermetic glass-to-metal (GM) seals are required mainly as electrical feed through for various types of gas based and electron devices, chemical process industries, including for packaging of power devices. The physico-chemical properties of glasses play important role in forming hermetic sealing with metals/alloys. The properties like thermal expansion coefficient, glass transition temperature, micro hardness, chemical durability etc. can be tailored by varying the glass composition by adding multi alkali and alkaline earth metal oxides to the base glass and varying the process parameters. We have prepared different types of glasses for the fabrication of different types of hermetic seals. Some of these are i) Lead silicate (LS) glass having SiO2, Na2O, K2O, BaO and PbO for compression type GM seals with SS304/Inconel and AISI 446 alloy ii) Borosilicate (BS) glass containing SiO2.Na2O.K20. Al2O3.B2O3 for matched type GM seals with Mo/ Kovar alloy and for uptake of synthetic dyes like Rhodamine 6G, Methylene Blue, Uranyl ions in process industries and nuclear industry iii) Sodium alumino phosphate (NAP) glass with P2O5-Na2O-B2O3-BaO- PbO for matched type GM seals with low melting metals (Al,Cu)/alloys like Cu-Be.

  11. Encapsulation of TRISO particle fuel in durable soda-lime-silicate glasses

    NASA Astrophysics Data System (ADS)

    Heath, Paul G.; Corkhill, Claire L.; Stennett, Martin C.; Hand, Russell J.; Meyer, Willem C. H. M.; Hyatt, Neil C.

    2013-05-01

    Tri-Structural Isotropic (TRISO) coated particle-fuel is a key component in designs for future high temperature nuclear reactors. This study investigated the suitability of three soda lime silicate glass compositions, for the encapsulation of simulant TRISO particle fuel. A cold press and sinter (CPS) methodology was employed to produce TRISO particle-glass composites. Composites produced were determined to have an aqueous durability, fracture toughness and Vickers' hardness comparable to glasses currently employed for the disposal of high level nuclear wastes. Sintering at 700 °C for 30 min was found to remove all interconnected porosity from the composite bodies and oxidation of the outer pyrolytic carbon layer during sintering was prevented by processing under a 5% H2/N2 atmosphere. However, the outer pyrolytic carbon layer was not effectively wetted by the encapsulating glass matrix. The aqueous durability of the TRISO particle-glass composites was investigated using PCT and MCC-1 tests combined with geochemical modelling. It was found that durability was dependent on silicate and calcium solution saturation. This study provides significant advancements in the preparation of TRISO particle encapsulant waste forms. The potential for the use of non-borosilicate sintered glass composites for TRISO particle encapsulation has been confirmed, although further refinements are required.

  12. Modeling of selenium telluride glass

    NASA Astrophysics Data System (ADS)

    Mauro, John C.; Varshneya, Arun K.

    2005-05-01

    We develop model interaction potentials for the heterogeneous selenium-tellurium system based on ab initio molecular simulations and a cluster expansion technique. The model potentials are used in classical Monte Carlo simulations to characterize the structure of SeTe glass in the canonical ensemble. The simulated structure is in good qualitative agreement with available experimental data.Figure 1. Computed structure of SeTe glass (20 Å × 20 Å × 20 Å subset). The smaller (gray) atoms are selenium, and the larger (blue) atoms are tellurium. The SeTe glass consists of homopolar Se and Te chains with very little heteropolar bonding.[Normal View 27K | Magnified View 58K]

  13. Disaster medicine through Google Glass.

    PubMed

    Carenzo, Luca; Barra, Federico Lorenzo; Ingrassia, Pier Luigi; Colombo, Davide; Costa, Alessandro; Della Corte, Francesco

    2015-06-01

    Nontechnical skills can make a difference in the management of disasters and mass casualty incidents and any tool helping providers in action might improve their ability to respond to such events. Google Glass, released by Google as a new personal communication device, could play a role in this field. We recently tested Google Glass during a full-scale exercise to perform visually guided augmented-reality Simple Triage and Rapid Treatment triage using a custom-made application and to identify casualties and collect georeferenced notes, photos, and videos to be incorporated into the debriefing. Despite some limitations (battery life and privacy concerns), Glass is a promising technology both for telemedicine applications and augmented-reality disaster response support to increase operators' performance, helping them to make better choices on the field; to optimize timings; and finally represents an excellent option to take professional education to a higher level. PMID:25460812

  14. Elastic Heterogeneity in Metallic Glasses

    NASA Astrophysics Data System (ADS)

    Dmowski, W.; Iwashita, T.; Chuang, C.-P.; Almer, J.; Egami, T.

    2010-11-01

    When a stress is applied on a metallic glass it deforms following Hook’s law. Therefore it may appear obvious that a metallic glass deforms elastically. Using x-ray diffraction and anisotropic pair-density function analysis we show that only about (3)/(4) in volume fraction of metallic glasses deforms elastically, whereas the rest of the volume is anelastic and in the experimental time scale deform without resistance. We suggest that this anelastic portion represents residual liquidity in the glassy state. Many theories, such as the free-volume theory, assume the density of defects in the glassy state to be of the order of 1%, but this result shows that it is as much as a quarter.

  15. DEVELOPMENT OF CRYSTAL-TOLERANT WASTE GLASSES

    SciTech Connect

    Matyas, Josef; Vienna, John D.; Kimura, Akihiko; Schaible, Micah J.; Tate, Rachel M.

    2010-10-26

    The loading of high-level waste in borosilicate glasses is limited by crystallinity constraints that cannot prevent crystal accumulation on the melter bottom and in the glass discharge riser of the melter. Pacific Northwest National Laboratory is studying variations in composition that are designed to constrain high-level waste glass compositions and develop the crystal-tolerant high-level waste glasses. These glasses will allow high waste loading without decreasing the lifetime of the melter by keeping the small spinel crystals suspended in the molten glass. Adding ~1 wt% of NiO to the baseline glass caused large spinel crystals to form up to 210 µm in size and resulted in the highest accumulation rate, ~ 227 mm/year, of all tested glasses. Noble metals that were added to high-Ni glass prevented large spinel crystals from forming and decreased the accumulation rate ~ 8.5 times. Adding ~5 wt% of Fe2O3 to the baseline glass resulted in a high number density of ~10-?m spinel crystals that remained suspended in the glass melt even after 17 days at 850°C. The accumulation rate of spinel crystals in high-chromia crucibles was only slightly higher compared with the accumulation rate in double crucibles. Only baseline glass exhibited about 2.6 times faster accumulation rate because of increased number of bigger crystals. These crystals were the result of glass enrichment with chromium that was leached out from the walls of high-chromia crucibles.

  16. Glasses for seeing beyond visible.

    PubMed

    Zhang, XiangHua; Bureau, Bruno; Lucas, Pierre; Boussard-Pledel, Catherine; Lucas, Jacques

    2008-01-01

    Conventional glasses based on oxides have a transparency limited by phonon absorption in the near IR region and have a limited interest for analyzing information located far beyond the visible. The IR spectral domain is nevertheless of prime interest, since it covers fundamental wavelength ranges used for thermal imaging as well as molecular vibrational signatures. Besides spectacular advances in the field of IR detectors, the main significant progresses are related to the development of IR glass optics, such as lenses or IR optical fibres. The field of IR glasses is almost totally dominated by glasses formed from heavy atoms such as the chalcogens S, Se and Te. Their transparency extends up to 12, 16 and 28 microm for sulfide-, selenide- and the new generation of telluride-based glasses, respectively. They cover the atmospheric transparency domains, 3-5 and 8-13 microm, respectively, at which the IR radiation can propagate allowing thermal imaging and night-vision operations through thick layers of atmosphere. The development of new glass compositions will be discussed on the basis of structural consideration with the objective of moulding low-cost lenses for IR cameras used, for instance, in car-driving assistance. Additionally, multimode, single-index, optical fibres operating in the 3 to 12 microm window developed for in situ remote evanescent-wave IR spectroscopy will also be mentioned. The detection of molecular IR signatures is applied to environmental monitoring for investigating the pollution of underground water with toxic molecules. The extension of this technique to the investigation of biomolecules in three different studies devoted to liver tissues analysis, bio-film formation, and cell metabolism will also be discussed. Finally we will mention the developments in the field of single-mode fibres operating around 10 mum for the Darwin space mission, which is aiming at discovering, signs of biological life in telluric earth-like exoplanets throughout the universe. PMID:18067106

  17. Crystallization of niobium germanosilicate glasses

    SciTech Connect

    Santos, Rodrigo; Wondraczek, Lothar

    2010-01-15

    Niobium germanosilicate glasses are potential candidates for the fabrication of transparent glass ceramics with interesting non-linear optical properties. A series of glasses in the (Ge,Si)O{sub 2}-Nb{sub 2}O{sub 5}-K{sub 2}O system were prepared by melting and casting and their characteristic temperatures were determined by differential thermal analysis. Progressive replacement of GeO{sub 2} by SiO{sub 2} improved the thermal stability of the glasses. Depending on the composition and the crystallization heat-treatment, different nanocrystalline phases-KNbSi{sub 2}O{sub 7}, K{sub 3}Nb{sub 3}Si{sub 2}O{sub 13} and K{sub 3.8}Nb{sub 5}Ge{sub 3}O{sub 20.4} could be obtained. The identification and characterization of these phases were performed by X-ray diffraction and Raman spectroscopy. The 40 GeO{sub 2}-10 SiO{sub 2}-25 Nb{sub 2}O{sub 5}-25 K{sub 2}O (mol%) composition presented the higher ability for volume crystallization and its nucleation temperature was determined by the Marotta's method. An activation energy for crystal growth of {approx}529 kJ/mol and a nucleation rate of 9.7x10{sup 18} m{sup -3} s{sup -1} was obtained, for this composition. Transparent glass ceramics with a crystalline volume fraction of {approx}57% were obtained after a 2 h heat-treatment at the nucleation temperature, with crystallite sizes of {approx}20 nm as determined by transmission electron microscopy. - Abstract: TEM image and XRD pattern of the glass ceramic produced (circles indicate nanocrystals).

  18. Corrosion of glass-bonded sodalite as a function of pH and temperature.

    SciTech Connect

    Morss, L. R.; Stanley, M.; Tatko, C.; Ebert, W. L.

    1999-11-29

    This paper reports the results of corrosion tests with monoliths of sodalite, binder glass, and glass-bonded sodalite, a ceramic waste form (CWF) that is being developed to immobilize radioactive electrorefiner salt used to condition spent sodium-bonded nuclear fuel. These tests were performed with dilute pH-buffered solutions in the pH range of 5-10 at temperatures of 70 and 90 C. The pH dependence of the forward dissolution rates of the CWF and its components have been determined. The pH dependence of the dissolution rates of sodalite, binder glass, and glass-bonded sodalite are similar to the pH dependence of dissolution rate of borosilicate nuclear waste glasses, with a negative pH dependence in the acidic region and a positive pH dependence in the basic region. Our results on the forward dissolution rates and their temperature and pH dependence will be used as components of a waste form degradation model to predict the long-term behavior of the CWF in a nuclear waste repository.

  19. Manufacturing unique glasses in space

    NASA Technical Reports Server (NTRS)

    Happe, R. P.

    1976-01-01

    An air suspension melting technique is described for making glasses from substances which to date have been observed only in the crystalline condition. A laminar flow vertical wind tunnel was constructed for suspending oxide melts that were melted using the energy from a carbon dioxide laser beam. By this method it is possible to melt many high-melting-point materials without interaction between the melt and crucible material. In addition, space melting permits cooling to suppress crystal growth. If a sufficient amount of under cooling is accompanied by a sufficient increase in viscosity, crystallization will be avoided entirely and glass will result.

  20. Quantitative approximation schemes for glasses

    E-print Network

    Matthieu Mangeat; Francesco Zamponi

    2015-10-13

    By means of a systematic expansion in $1/d$ around the infinite-dimensional solution, we obtain an approximation scheme to compute properties of glasses in low dimensions. The resulting equations take as input the thermodynamic and structural properties of the equilibrium liquid, and from this they allow one to compute properties of the glass. They are therefore similar in spirit to the Mode-Coupling approximation scheme. Our scheme becomes exact, by construction, in $d\\to\\infty$ and it can be improved systematically by adding more terms in the $1/d$ expansion.

  1. Glass Transition in Confined Geometry

    E-print Network

    Simon Lang; Vitalie Botan; Martin Oettel; David Hajnal; Thomas Franosch; Rolf Schilling

    2010-08-23

    Extending mode-coupling theory, we elaborate a microscopic theory for the glass transition of liquids confined between two parallel flat hard walls. The theory contains the standard MCT equations in bulk and in two dimensions as limiting cases and requires as input solely the equilibrium density profile and the structure factors of the fluid in confinement. We evaluate the phase diagram as a function of the distance of the plates for the case of a hard sphere fluid and obtain an oscillatory behavior of the glass transtion line as a result of the structural changes related to layering.

  2. Antiferromagnetic inclusions in lunar glass

    USGS Publications Warehouse

    Thorpe, A.N.; Senftle, F.E.; Briggs, Charles; Alexander, Corrine

    1974-01-01

    The magnetic susceptibility of 11 glass spherules from the Apollo 15, 16, and 17 fines and two specimens of a relatively large glass spherical shell were studied as a function of temperature from room temperature to liquid helium temperatures. All but one specimen showed the presence of antiferromagnetic inclusions. Closely spaced temperature measurements of the magnetic susceptibility below 77 K on five of the specimens showed antiferromagnetic temperature transitions (Ne??el transitions). With the exception of ilmenite in one specimen, these transitions did not correspond to any transitions in known antiferromagnetic compounds. ?? 1974.

  3. Molecular random tilings as glasses

    PubMed Central

    Garrahan, Juan P.; Stannard, Andrew; Blunt, Matthew O.; Beton, Peter H.

    2009-01-01

    We have recently shown that p-terphenyl-3,5,3?,5?-tetracarboxylic acid adsorbed on graphite self-assembles into a two-dimensional rhombus random tiling. This tiling is close to ideal, displaying long-range correlations punctuated by sparse localized tiling defects. In this article we explore the analogy between dynamic arrest in this type of random tilings and that of structural glasses. We show that the structural relaxation of these systems is via the propagation–reaction of tiling defects, giving rise to dynamic heterogeneity. We study the scaling properties of the dynamics and discuss connections with kinetically constrained models of glasses. PMID:19720990

  4. Experimental studies of glass refining

    NASA Technical Reports Server (NTRS)

    Subramanian, R. S.; Cole, R.; Kondos, P.

    1984-01-01

    The basic components of the experimental apparatus were selected and acquired. Techniques were developed for the fabrication of the special crucibles necessary for the experiments. Arrangements were made for the analysis of glass and gas bubble samples for composition information. Donations of major equipment were received for this project from Owens, Illinois where a similar study had been conducted a few year ago. Decisions were made regarding the actual glass composition to be used, the gas to be used in the first experiments, and the temperatures at which the experiments should be conducted. A microcomputer was acquired, and work was begun on interfacing the video analyzer to it.

  5. Molecular structure and intermediate phases in group-V binary chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Georgiev, Daniel Georgiev

    Chalcogenide glasses offer unique opportunities for basic science and technological applications. The physical properties of such network-forming glasses, including the glass-forming tendency, are intimately connected to global connectivity of their backbones. In particular, the elastic behavior of glasses leads to the existence of three distinct phases that appears to be generic in network forming systems. Weakly cross-linked networks are mechanically soft and form floppy phases. Optimally cross-linked networks lead to stress-free or self-organized networks, and are identified with intermediate phases. Strongly cross-linked networks are mechanically stiff and usually form part of stressed-rigid phases. The floppy-intermediate and stressed-rigid classification of the group V chalcogenides is recognized in this work for the first time. The glass systems examined include P-Se, As-Se, and As-S. Thermally reversing windows (glass compositions wherein Tg become almost completely reversing) are observed in the three binary glass systems using temperature-Modulated Differential Scanning Calorimetry (MDSC), and are identified with the opening of (non-mean-field) intermediate phases . The molecular structure of these glasses is studied by Raman scattering, MDSC and 31P NMR, and the local structures responsible for intermediate phases are identified with assistance from constraint counting procedures. Raman scattering and Nuclear Magnetic Resonance (NMR) results on P-Se glasses provide compelling evidence for existence of four-fold coordinated phosphorous species that are bonded to three bridging and one terminal selenium, Se = P(Se1/2)3. The structure results provide a basis to quantitatively understand compositional trends in Tg in the stochastic agglomeration limit. The existence of analog four-fold coordinated As species is suggested by MDSC experiments on As-Se glasses. Our experimental results also show that stressed-rigid phases in the examined glasses are usually phase separated on a molecular level. Phase separation initiates near the stoichiometric composition, As2S3, and grows as the As content, x, of binary As xS1-x glasses exceeds 0.38. Similar behavior has been observed in As-Se and P-Se glasses. A new understanding of global maxima in glass transition temperatures near stoichiometric compositions has emerged. These maxima are the result of a decrease in network connectivity as the backbone nano-scale phase separates.

  6. Analysis of Nuclear Reconstitution, Nuclear

    E-print Network

    Forbes, Douglass

    CHAPTER Analysis of Nuclear Reconstitution, Nuclear Envelope Assembly, and Nuclear Pore Assembly ....................................................................... 180 8.5 Assaying Assembly and Integrity of the Nuclear Envelope................................... 182 8.6 A Nuclear Pore Complex Assembly Assay Using pore-free Nuclear Intermediates

  7. Alkali borosilicate glass by fly ash from a coal-fired power plant.

    PubMed

    Park, Jong Soo; Taniguchi, Shoji; Park, Young Jun

    2009-01-01

    The possibility of using coal fly ash as a silica source for alkali borosilicate glass was investigated. Alkali borosilicate glasses were prepared from the coal fly ash mixed with 30 wt.% reagents composed of Na(2)O and B(2)O(3) by susceptor-induction heating. Their densities ranged from 2.24 to 2.55 g cm(-3) and decreased as the amount of B(2)O(3) addition increased. However, the Vickers microhardness showed a different tendency with the density since the glass network connectivity improved by boron anomaly, which was identified by a nuclear magnetic resonance analysis. The Vickers microhardness of the glass product, with the addition of 15 wt.% B(2)O(3) and 15 wt.% Na(2)O, was about 4030 MPa. Furthermore, the changes in microstructure were consistent with those in the chemical stability by the toxicity characteristic leaching procedure (TCLP). PMID:18951607

  8. Effect of Bubbles and Silica Dissolution on Melter Feed Rheology during Conversion to Glass

    SciTech Connect

    Marcial, Jose; Chun, Jaehun; Hrma, Pavel R.; Schweiger, Michael J.

    2014-10-21

    As the nuclear waste glass melter feed is converted to molten glass, the feed becomes a continuous glass-forming melt where dissolving refractory constituents are suspended together with numerous gas bubbles. Knowledge of mechanical properties of the reacting melter feed is crucial for understanding the feed-to-glass conversion as it occurs during melting. We studied the melter feed viscosity during heating and correlated it with volume fractions of dissolving quartz particles and gas phase. The measurements were performed with a rotating spindle rheometer on the melter feed heated at 5 K/min, starting at several different temperatures. The effects of undissolved quartz particles, gas bubbles, and compositional inhomogeneity on the melter feed viscosity were determined by fitting a linear relationship between log viscosity and volume fractions of suspended phases.

  9. Results of drip tests on sludge-based and actinide-doped glasses

    SciTech Connect

    Bates, J.K.; Buck, E.C.

    1994-04-01

    The reaction of three differs simulated nuclear waste glasses is being evaluated using a test method that slowly drips water onto a glass/metal assembly. The tests have been in progress for up to eight years and are being performed with as-cast and glass aged by reaction with water vapor. Results are presented for the cumulative release of Np, Pu, and Am as a function of time; also reported are the particulate species that have been detected suspended in solution. A significant difference is noted in the suspended species depending on the glass composition, and on whether the glass is aged. With as-cast glass, the radioactivity is associated with the suspended particles, while with the aged glass, the solution has a high initial anion content, and the transuranic elements appear to be dissolved in solution, since they pass through filters with small pore sizes. Examples are given of possible tests to evaluate the interaction between these test solutions and potential engineered barrier components.

  10. Survey of Potential Glass Compositions for the Immobilisation of the UK's Separated Plutonium Stocks

    SciTech Connect

    Harrison, Mike T.; Scales, Charlie R.; Bingham, Paul A.; Hand, Russell J.

    2007-07-01

    The Nuclear Decommissioning Authority (NDA) has taken over ownership of the majority of the UK's separated civil plutonium stocks, which are expected to exceed 100 metric tons by 2010. Studies to technically underpin options development for the disposition of these stocks, for example by immobilization or re-use as fuel, are being carried out by Nexia Solutions on behalf of NDA. Three classes of immobilization matrices have been selected for investigation by means of previous studies and stakeholder dialogue: ceramic or crystalline waste-forms, storage MOx, and vitreous or glass-based waste-forms. This paper describes the preliminary inactive experimental program for the vitrification option, with results from a wide range of glass compositions along with conclusions on their potential use for plutonium immobilization. Following review, four glass systems were selected for preliminary investigation: borosilicate, lanthanide borosilicate, aluminosilicate and phosphate glasses. A broad survey of glass properties was completed in order to allow meaningful evaluation, e.g. glass formulation, waste loading, chemical durability, thermal properties, and viscosity. The program was divided into two parts, with silicate and phosphate glasses being investigated by Nexia Solutions and the Immobilisation Science Laboratory (ISL) at the University of Sheffield respectively. (authors)

  11. Hydration effects on the structural and vibrational properties of yttrium aluminosilicate glasses for in situ radiotherapy.

    PubMed

    Malik, Jahangir; Tilocca, Antonio

    2013-11-21

    The performances of silicate glasses as containment matrices or vectors of radioactive ions in nuclear waste storage and in situ radiotherapy are influenced by the effect of interstitial water on the glass durability. In order to assess how hydration determines changes to atomistic structural features which control the glass degradation, we have carried out molecular dynamics simulations of a typical yttrium aluminosilicate (YAS) glass employed in radiotherapy, incorporating different water contents. The analysis of the models allows us to discuss the way in which hydroxyl groups are distributed in the glass structure and modify or disrupt the aluminosilicate glass network. Hydration affects the silicate and aluminate connectivity to a different extent, resulting in a different degree of disruption (depolymerization) of the Si and Al network. The simulations also highlight a strong tendency of all hydrated compositions to form Y(3+)- and OH(-)-rich domains, separated from the aluminosilicate matrix. The implications of these structural effects for the durability and ion release behavior of the glass are discussed, as well as the vibrational signatures of the various hydrous species identified in the models. PMID:24206236

  12. Development of iodine waste forms using low-temperature sintering glass.

    SciTech Connect

    Krumhansl, James Lee; Nenoff, Tina Maria; Garino, Terry J.; Rademacher, David

    2010-06-01

    This presentation will describe our recent work on the use of low temperature-sintering glass powders mixed with either AgI or AgI-zeolite to produce a stable waste form. Radioactive iodine ({sup 129}I, half-life of 1.6 x 10{sup 7} years) is generated in the nuclear fuel cycle and is of particular concern due to its extremely long half-life and its effects on human health. As part of the DOE/NE Advanced Fuel Cycle Initiative (AFCI), the separation of {sup 129}I from spent fuel during fuel reprocessing is being studied. In the spent fuel reprocessing scheme under consideration, the iodine is released in gaseous form and collected using Ag-loaded zeolites, to form AgI. Although AgI has extremely low solubility in water, it has a relatively high vapor pressure at moderate temperatures (>550 C), thus limiting the thermal processing. Because of this, immobilization using borosilicate glass is not feasible. Therefore, a bismuth oxide-based glasses are being studied due to the low solubility of bismuth oxide in aqueous solution at pH > 7. These waste forms were processed at 500 C, where AgI volatility is low but the glass powder is able to first densify by viscous sintering and then crystallize. Since the glass is not melted, a more chemically stable glass can be used. The AgI-glass mixture was found to have high iodine leach resistance in these initial studies.

  13. Transparent BaCl(sub 2}:Eu{sup 2+} glass scintillator.

    SciTech Connect

    Chen, G.; Johnson, J.; Schweizer, S.; Woodford, J.; Newman, P.; MacFarlane, D.; Energy Technology; Univ. of Paderborn; Monash Univ.

    2006-01-01

    Scintillators are the backbone of high-energy radiation detection devices. Most scintillators are based on inorganic crystals that have applications in medical radiography, nuclear medicine, security inspection, dosimetry, and high-energy physics. In this paper, we present a new type of scintillator that is based on glass ceramics (composites of glasses and crystals). These scintillators are made from Eu{sup 2+}-activated fluorozirconate glasses that are co-doped with Ba{sup 2+}, La{sup 3+}, Al{sup 3+}, Na{sup +}, and Cl{sup -}. Subsequent heat treatment of the glasses forms BaCl{sub 2} nano-crystals (10-20 nm in size) that are embedded in the glass matrix. The resulting scintillators are transparent, efficient, inexpensive to fabricate, and easy to scale up. The physical structure and x-ray imaging performance of these glass-ceramic scintillators are presented, and an application of these materials to micro-computed tomography is demonstrated. Our study suggests that these glass-ceramic scintillators have high potential for medical x-ray imaging.

  14. Q-Speciation and Network Structure Evolution in Invert Calcium Silicate Glasses.

    PubMed

    Kaseman, Derrick C; Retsinas, A; Kalampounias, A G; Papatheodorou, G N; Sen, S

    2015-07-01

    Binary silicate glasses in the system CaO-SiO2 are synthesized over an extended composition range (42 mol % ? CaO ? 61 mol %), using container-less aerodynamic levitation techniques and CO2-laser heating. The compositional evolution of Q speciation in these glasses is quantified using (29)Si and (17)O magic angle spinning nuclear magnetic resonance spectroscopy. The results indicate progressive depolymerization of the silicate network upon addition of CaO and significant deviation of the Q speciation from the binary model. The equilibrium constants for the various Q species disproportionation reactions for these glasses are found to be similar to (much smaller than) those characteristic of Li (Mg)-silicate glasses, consistent with the corresponding trends in the field strengths of these modifier cations. Increasing CaO concentration results in an increase in the packing density and structural rigidity of these glasses and consequently in their glass transition temperature Tg. This apparent role reversal of conventional network-modifying cations in invert alkaline-earth silicate glasses are compared and contrasted with that in their alkali silicate counterparts. PMID:26047056

  15. 4. View showing underside of wing, looking glass aircraft. View ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. View showing underside of wing, looking glass aircraft. View to north. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  16. 5. Headon view of looking glass aircraft. View to southwest. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Head-on view of looking glass aircraft. View to southwest. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  17. 3. General view showing rear of looking glass aircraft. View ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. General view showing rear of looking glass aircraft. View to north. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  18. 24 CFR 3280.113 - Glass and glazed openings.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 2012-04-01 false Glass and glazed openings. 3280.113 Section... Planning Considerations § 3280.113 Glass and glazed openings. (a) Windows and sliding glass doors. All windows and sliding glass...

  19. 24 CFR 3280.113 - Glass and glazed openings.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 2010-04-01 false Glass and glazed openings. 3280.113 Section... Planning Considerations § 3280.113 Glass and glazed openings. (a) Windows and sliding glass doors. All windows and sliding glass...

  20. 24 CFR 3280.113 - Glass and glazed openings.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 2011-04-01 false Glass and glazed openings. 3280.113 Section... Planning Considerations § 3280.113 Glass and glazed openings. (a) Windows and sliding glass doors. All windows and sliding glass...

  1. 24 CFR 3280.113 - Glass and glazed openings.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 2013-04-01 false Glass and glazed openings. 3280.113 Section... Planning Considerations § 3280.113 Glass and glazed openings. (a) Windows and sliding glass doors. All windows and sliding glass...

  2. Signatures of structural recovery in colloidal glasses.

    PubMed

    Di, Xiaojun; Win, K Z; McKenna, Gregory B; Narita, Tetsuharu; Lequeux, François; Pullela, Srinivasa Rao; Cheng, Zhengdong

    2011-03-01

    Colloids near the glass concentration are often taken as models for molecular glasses. Yet, an important aspect of the dynamics of molecular glasses, structural recovery, has not been elucidated in colloids. We take advantage of a thermosensitive colloidal suspension to study the structural recovery after concentration jumps by using diffusing wave spectroscopy. The three classical aging signatures observed in molecular glasses are studied and the results are compared with those typical of molecular glasses. For the intrinsic isotherms, unlike molecular glasses, the colloid shows huge changes in relaxation time at equilibrium while the times required to reach the equilibrium state are nearly constant. For asymmetry of approach, we find a similar nonlinearity to that observed in the molecular glasses. For the memory experiment, while a memory effect is seen, the response is qualitatively different from that in molecular glasses. PMID:21405637

  3. Additive Manufacturing of Optically Transparent Glass

    E-print Network

    Klein, John

    We present a fully functional material extrusion printer for optically transparent glass. The printer is composed of scalable modular elements able to operate at the high temperatures required to process glass from a molten ...

  4. SOURCE ASSESSMENT: GLASS CONTAINER MANUFACTURING PLANTS

    EPA Science Inventory

    The report summarizes results of a study to gather and analyze background information and technical data related to air emissions from glass container manufacturing operations. It covers emissions from three plant areas: raw materials preparation and handling, glass melting, and ...

  5. High modulus high temperature glass fibers

    NASA Technical Reports Server (NTRS)

    Bacon, J. F.

    1973-01-01

    The search for a new high-modulus, high-temperature glass fiber involved the preparation of 500 glass compositions lying in 12 glass fields. These systems consisted primarily of low atomic number oxides and rare-earth oxides. Direct optical measurements of the kinetics of crystallization of the cordierite-rare earth system, for example, showed that the addition of rare-earth oxides decreased the rate of formation of cordierite crystals. Glass samples prepared from these systems proved that the rare-earth oxides made large specific contributions to the Young's modulus of the glasses. The best glasses have moduli greater than 21 million psi, the best glass fibers have moduli greater than 18 million psi, and the best glass fiber-epoxy resin composites have tensile strengths of 298,000 psi, compressive strengths of at least 220,000 psi, flexural strengths of 290,000 psi, and short-beam shear strengths of almost 17,000 psi.

  6. High-Intensity Plasma Glass Melter

    SciTech Connect

    2004-01-01

    Modular high-intensity plasma melter promises improved performance, reduced energy use, and lower emissions. The glass industry has used the same basic equipment for melting glass for the past 100 years.

  7. Structure glass technology : systems and applications

    E-print Network

    Leitch, Katherine K. (Katherine Kristen)

    2005-01-01

    Glass cannot compete with steel in terms of strength or durability, but it is the only structural material that offers the highly sought after qualities of translucency and transparency. The use of glass has evolved from ...

  8. Tougher glasses for eye-safe lasers

    NASA Astrophysics Data System (ADS)

    George, Simi; Vullo, Paula

    2015-05-01

    Phosphate glasses are known to produce high gain for the Er3+ emission into 1540nm, especially when sensitized with Yb. Unfortunately, the phosphate glass matrix tends to be weaker than other available amorphous materials. Being that glasses are engineerable, a study was initiated in order to strengthen the glass structure of a commercially available phosphate laser glass without impacting its laser output efficiencies. Secondly, we seek to understand the impact of the various glass modifiers that drive thermal shock resistance of phosphate glasses on the Er emission manifolds. This report details a number of compositions that were designed, melted and analyzed for properties. Laser output performance results for the glasses that met the targeted parameters are presented.

  9. Tellurite glass as a waste form for a simulated mixed chloride waste stream: Candidate materials selection and initial testing

    SciTech Connect

    Riley, Brian J.; Rieck, Bennett T.; McCloy, John S.; Crum, Jarrod V.; Sundaram, S. K.; Vienna, John D.

    2012-02-02

    Tellurite glasses have been researched widely for the last 60 years since they were first introduced by Stanworth. These glasses have been primarily used in research applications as glass host materials for lasers and as non-linear optical materials, though many other uses exist in the literature. Tellurite glasses have long since been used as hosts for various, and even sometimes mixed, halogens (i.e., multiple chlorides or even chlorides and iodides). Thus, it was reasonable to expect that these types of glasses could be used as a waste form to immobilize a combination of mixed chlorides present in the electrochemical separations process involved with fuel separations and processing from nuclear reactors. Many of the properties related to waste forms (e.g., chemical durability, maximum chloride loading) for these materials are unknown and thus, in this study, several different types of tellurite glasses were made and their properties studied to determine if such a candidate waste form could be fabricated with these glasses. One of the formulations studied was a lead tellurite glass, which had a low sodium release and is on-par with high-level waste silicate glass waste forms.

  10. Scattering off the Color Glass Condensate

    E-print Network

    Heikki Mäntysaari

    2015-06-24

    In this thesis the Color Glass Condensate (CGC) framework, which describes quantum chromodynamics (QCD) at high energy, is applied to various scattering processes. Higher order corrections to the CGC evolution equations, known as the BK and JIMWLK equations, are also considered. It is shown that the leading order CGC calculations describe the experimental data from electron-proton deep inelastic scattering (DIS), proton-proton and proton-nucleus collisions. The initial condition for the BK evolution equation is obtained by performing a fit to deep inelastic scattering data. The fit result is used as an input to calculations of single particle spectra and nuclear suppression in proton-proton and proton-nucleus collisions, which are shown to be in agreement with RHIC and LHC measurements. In particular, the importance of a proper description of the nuclear geometry consistently with the DIS data fits is emphasized, as it results in a nuclear suppression factor $R_{pA}$ which is consistent with the available experimental data. In addition to single particle production, the correlations between two hadrons at forward rapidity are computed. The RHIC measurements are shown to be naturally explainable in the CGC framework, and the previous CGC calculations are improved by including the so called inelastic and double parton scattering contributions. This improvement is shown to be required in order to get results compatible with the experimentally measured correlations. Exclusive vector meson production, which can be a powerful tool to study the gluonic structure of nuclei at small Bjorken-$x$, is also considered. The cross sections are calculated within the CGC framework in the context of a future electron-ion collider. In particular, the cross section for incoherent diffractive vector meson production is derived and a centrality estimator for this process is proposed.

  11. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... glasses, and flat plate type gauge glasses. (a) Cargo tanks may have sighting ports as a secondary...

  12. Objective: We assess the driving distraction potential of texting with Google Glass (Glass), a mobile

    E-print Network

    DeMara, Ronald F.

    Objective: We assess the driving distraction potential of texting with Google Glass (Glass and widely banned. Supporters of Glass claim the head-mounted wearable computer is designed to deliver decisions incorpo- rated in Glass might facilitate messaging for drivers. Method: We asked drivers

  13. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... glasses, and flat plate type gauge glasses. (a) Cargo tanks may have sighting ports as a secondary...

  14. Glass Transition and the Coulomb Gap in Electron Glasses M. Muller and L. B. Ioffe

    E-print Network

    Müller, Markus

    Glass Transition and the Coulomb Gap in Electron Glasses M. Mu¨ller and L. B. Ioffe Department December 2004) We establish the connection between the presence of a glass phase and the appearance correlations in a systematic way, we show that in the case of strong disorder a continuous glass transition

  15. Disconnected Glass-Glass Transitions and Diffusion Anomalies in a Model with Two Repulsive Length Scales

    E-print Network

    Stanley, H. Eugene

    Disconnected Glass-Glass Transitions and Diffusion Anomalies in a Model with Two Repulsive Length-coupling-theory calculations, we report a novel scenario for multiple glass tran- sitions in a purely repulsive spherical potential: the square shoulder. The liquid-glass transition lines exhibit both melting by cooling

  16. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... glasses, and flat plate type gauge glasses. (a) Cargo tanks may have sighting ports as a secondary...

  17. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... glasses, and flat plate type gauge glasses. (a) Cargo tanks may have sighting ports as a secondary...

  18. 46 CFR 154.1320 - Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Sighting ports, tubular gauge glasses, and flat plate type gauge glasses. 154.1320 Section 154.1320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... glasses, and flat plate type gauge glasses. (a) Cargo tanks may have sighting ports as a secondary...

  19. Draining our Glass: An Energy and Heat Characterization of Google Glass

    E-print Network

    Zhong, Lin

    Draining our Glass: An Energy and Heat Characterization of Google Glass Robert LiKamWa, Zhen Wang The Google Glass is a mobile device designed to be worn as eyeglasses. This form factor enables new use cases resources on a hands-free display. Recent interest has drawn to Google's spectacle- shaped device, Glass

  20. Crystallization of a barium-aluminosilicate glass

    NASA Technical Reports Server (NTRS)

    Drummond, C. H., III; Lee, W. E.; Bansal, N. P.; Hyatt, M. J.

    1989-01-01

    The crystallization of a celsian glass composition was investigated as a possible high-temperature ceramic matrix material. Heat treatments invariably resulted in crystallization of the hexaclesian phase unless a flux, such as lithia, was added or a nucleating agent used (e.g., celsian seeds). TEM analysis revealed complex microstructures. Glasses with Mo additions contained hexacelsian, mullite, and an Mo-rich glass. Li2O additions stabilized celsian but mullite and Mo-rich glass were still present.

  1. Development of cesium containing glass for gamma irradiator

    NASA Astrophysics Data System (ADS)

    Shah, J. G.; Wattal, P. K.

    2009-07-01

    Cesium137 is considered an alternative candidate for the gamma source to be used in irradiators in place of CO60 because it is a long-lived gamma emitter and is a by-product of nuclear fission. Large quantities of Cs137 have been present in stored fission product high level waste and much larger quantities are potentially available from the operation of nuclear power reaction. Cs is isolated from the high level waste by Cs specific sorbant and converted in to glassy form to have safe use of highly radiotoxic isotope for irradiators in public domain. Several glass compositions containing Cs (Cs137-simulation) in the ternary system of Cesium Iron Phosphate (Cs2O-Fe2O3-P2O5), Cesium Borosilicate (Cs2O-B2O3-SiO2) and quaternary system of Cesium Sodium Borosilicate (Cs2O-Na2O-B2O3-SiO2), Cesium Lithium Borosilicate (Cs2O-Li2O-B2O3-SiO2) with minor additives like Al, Zn with varying concentration of Cs2O were prepared. Basic characteristics like fusion temperature, pouring temperature, homogeneity of the melt and its durability at room temperature in air (Hygroscopic nature) were noted for screening probable candidate glass formulation. The selected glass formulation was further characterized for its thermal properties like volatility loss at melting temperature, glass transition temperature and linear expansion coefficient by thermal analyzer and homogeneity by SEM/EDX and XRD.

  2. Heating-induced glass-glass and glass-liquid transformations in computer simulations of water

    NASA Astrophysics Data System (ADS)

    Chiu, Janet; Starr, Francis W.; Giovambattista, Nicolas

    2014-03-01

    Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T "phase diagram" for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related, both being associated with the limit of kinetic stability of LDA (HDA).

  3. Heating-induced glass-glass and glass-liquid transformations in computer simulations of water.

    PubMed

    Chiu, Janet; Starr, Francis W; Giovambattista, Nicolas

    2014-03-21

    Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T "phase diagram" for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related, both being associated with the limit of kinetic stability of LDA (HDA). PMID:24655190

  4. Heating-induced glass-glass and glass-liquid transformations in computer simulations of water

    SciTech Connect

    Chiu, Janet; Giovambattista, Nicolas; Starr, Francis W.

    2014-03-21

    Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T “phase diagram” for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related, both being associated with the limit of kinetic stability of LDA (HDA)

  5. Friction behavior of glass and metals in contact with glass in various environments

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1973-01-01

    Sliding friction experiments have been conducted for heat-resistant glass and metals in contact with glass. These experiments were conducted in various environments including vacuum, moist air, dry air, octane, and stearic acid in hexadecane. Glass exhibited a higher friction force in moist air than it did in vacuum when in sliding contact with itself. The metals, aluminum, iron, and gold, all exhibited the same friction coefficient when sliding on glass in vacuum as glass sliding on glass. Gold-to-glass contacts were extremely sensitive to the environment despite the relative chemical inertness of gold.

  6. Method for milling and drilling glass

    NASA Technical Reports Server (NTRS)

    Rice, S. H. (inventor)

    1980-01-01

    A process for machining glass by placing a rotating carbide working surface under minimum pressure against an area of glass to be worked is described. Concurrently the region between the working surface and the area of glass is wet with a lubricant consisting essentially of a petroleum carrier, a complex mixture of esters and a complex mixture of naturally occurring aromatic oils.

  7. Jagged Edges of the Glass Ceiling

    ERIC Educational Resources Information Center

    Robinson, Victoria L.

    2004-01-01

    Although many aspiring young women might believe the glass ceiling was shattered a decade ago, they still need to understand how that glass ceiling impacted an older generation of women in educational leadership. They also must be aware that some segments of the glass ceiling might still exist. This article provides a historical overview of the…

  8. 7 CFR 3201.30 - Glass cleaners.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Glass cleaners. 3201.30 Section 3201.30 Agriculture... Items § 3201.30 Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass surfaces, such as windows, mirrors, car windows, and computer monitors. (b) Minimum...

  9. A Topological Glass JeanPierre Eckmann

    E-print Network

    A Topological Glass Jean­Pierre Eckmann Dâ??epartement de Physique Thâ??eorique et Section de Math glasses. Finally, we show that the evolution can be described as that of a rarefied gas with spontaneous generation of particles and annihilating collisions. 1 Introduction Our model of a glass can is inspired

  10. 7 CFR 3201.30 - Glass cleaners.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Glass cleaners. 3201.30 Section 3201.30 Agriculture... Items § 3201.30 Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass surfaces, such as windows, mirrors, car windows, and computer monitors. (b) Minimum...

  11. SAND REPORT Material Characterization of Glass,

    E-print Network

    SAND REPORT Material Characterization of Glass, Carbon, and Hybrid-Fiber SCRIMP Panels Akira e #12;SAND2002-3538 Unlimited Release Printed December 2002 Material Characterizationof Glass was to generate the material database for carbon and glass composite panels created by the SCRIMP process

  12. 7 CFR 3201.30 - Glass cleaners.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Glass cleaners. 3201.30 Section 3201.30 Agriculture... Items § 3201.30 Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass surfaces, such as windows, mirrors, car windows, and computer monitors. (b) Minimum...

  13. Nickel-iron spherules from aouelloul glass

    USGS Publications Warehouse

    Chao, E.C.T.; Dwornik, E.J.; Merrill, C.W.

    1966-01-01

    Nickel-iron spherules, ranging from less than 0.2 to 50 microns in diameter and containing 1.7 to 9.0 percent Ni by weight, occur in glass associated with the Aouelloul crater. They occur in discrete bands of siliceous glass enriched in dissolved iron. Their discovery is significant tangible evidence that both crater and glass originated from terrestrial impact.

  14. Glasses for Solar-Cell Arrays

    NASA Technical Reports Server (NTRS)

    Bouquet, F. L.

    1982-01-01

    Report presents data on glass for encapsulation of solar-cell arrays, with special emphasis on materials and processes for automated high-volume production of low-cost arrays. Commercial suppliers of glass are listed. Factors that affect the cost of glass are examined: type (sheet, float, or plate), formulation, and energy consumed in manufacturing.

  15. Digimarc Discover on Google Glass

    NASA Astrophysics Data System (ADS)

    Rogers, Eliot; Rodriguez, Tony; Lord, John; Alattar, Adnan

    2015-03-01

    This paper reports on the implementation of the Digimarc® Discover platform on Google Glass, enabling the reading of a watermark embedded in a printed material or audio. The embedded watermark typically contains a unique code that identifies the containing media or object and a synchronization signal that allows the watermark to be read robustly. The Digimarc Discover smartphone application can read the watermark from a small portion of printed image presented at any orientation or reasonable distance. Likewise, Discover can read the recently introduced Digimarc Barcode to identify and manage consumer packaged goods in the retail channel. The Digimarc Barcode has several advantages over the traditional barcode and is expected to save the retail industry millions of dollars when deployed at scale. Discover can also read an audio watermark from ambient audio captured using a microphone. The Digimarc Discover platform has been widely deployed on the iPad, iPhone and many Android-based devices, but it has not yet been implemented on a head-worn wearable device, such as Google Glass. Implementing Discover on Google Glass is a challenging task due to the current hardware and software limitations of the device. This paper identifies the challenges encountered in porting Discover to the Google Glass and reports on the solutions created to deliver a prototype implementation.

  16. Spin glasses - A grey memory

    NASA Astrophysics Data System (ADS)

    Carré, E.; Préjean, J. J.; Souletie, J.

    1986-02-01

    We discuss the relaxation of the magnetization of a spin glass in terms of the variable Wc = kT ln t/? 0 which follows from the Arrhenius law. We show how successive magnetizing and demagnetizing processes can induce non-monotonic relaxations of M in terms of either time or temperature.

  17. Impact of rare earth element clusters on the excited state lifetime evolution under irradiation in oxide glasses.

    PubMed

    Pukhkaya, Vera; Goldner, Philippe; Ferrier, Alban; Ollier, Nadège

    2015-02-01

    Rare earth doped active glasses and fibers can be exposed to ionizing radiations in space and nuclear applications. In this work, we analyze the evolution of (2)F(5/2) excited state lifetime in Yb(3+) ions in irradiated aluminosilicate glasses by electrons and ? rays. It is found that the variation of lifetimes depends on the Yb(3+) clusters content of the glasses for irradiation doses in the 10(2)- 1.5?10(9) Gy range. In particular, glasses with high clustering show a smaller decrease in lifetime with increasing radiation dose. This behavior is well correlated to the variation in paramagnetic defects concentration determined by electron paramagnetic resonance. This effect is also observed in Yb(3+) doped phosphate and Er(3+) doped aluminosilicate glasses, inferring that clustering plays an important role in irradiation induced quenching. PMID:25836185

  18. Structure and the physicochemical properties of glasses and glass melts

    NASA Astrophysics Data System (ADS)

    Kucuk, Ahmet

    1999-11-01

    A user friendly experimental procedure (sessile and pendant drop arrangements) and calculation routine were developed to measure the physicochemical properties such as density, surface tension, and volatilization of glasses and glass melts at the temperature range of 500 to 1500°C. The influence of volatilization on the composition, density and surface tension of potassium, sodium silicate and soda lime silica melts at 1400°C was investigated using the sessile and pendant drop arrangements, diffuse reflectance Fourier transform spectrometry and electronic-balance. Volatilization of alkali from the melts was modeled as a combined mechanism that included diffusion of volatile species from bulk to surface and chemical decomposition reaction of alkali oxide on the surface. The surface tension of experimental and commercial glass melts, some containing iron, was measured under various atmospheres including 4%H 2/96%Ar, dry argon, dry air and wet air using the sessile drop and pendant drop arrangements. In general, the surface tension of the melts decreased in the given order: argon, dry air and wet air. OH groups from water vapor in the atmosphere behave as a surface active species according to the Gibbs adsorption equation and form a mono-layer on the surface with certain number of molecules according to the Langmuir adsorption theorem. The number of OH-like molecules in the monolayer is higher for the melts containing high ionic strength ions. Iron containing melts have higher surface tension and density for higher Fe2+/Fe3+ ratios. The presence of four-coordinated Fe3+ ions rather than six-coordinated Fe 2+ in the surface of iron bearing glass melts was found to be energetically more favorable. The structures of potassium and lithium silicate glasses and melts were modeled using the molecular dynamics simulation at 300 K and 1700 K, respectively. Despite of the excellent agreement between modeled and experimentally determined structure in the short range, modeled glass structure (at 300 K) deviated from the actual structure in the medium range while modeled melt structure conserved the agreement with the experimental structure. The surface structures of potassium silicate melts were also modeled at 1700 K.

  19. Crystallization Kinetics in Fluorochloroziroconate Glass-Ceramics

    NASA Astrophysics Data System (ADS)

    Alvarez, Carlos J.

    Annealing fluorochlorozirconate (FCZ) glasses nucleates BaCl2 nanocrystals in the glass matrix, resulting in a nanocomposite glass-ceramic that has optical properties suitable for use as a medical X-ray imaging plate. Understanding the way in which the BaCl¬2 nanocrystal nucleation, growth and phase transformation processes proceed is critical to controlling the optical behavior. However, there is a very limited amount of information about the formation, morphology, and distribution of the nanocrystalline particles in FCZ glass-ceramics. In this thesis, the correlation between the microstructure and the crystallization kinetics of FCZ glass-ceramics, are studied in detail. In situ X-ray diffraction and transmission electron microscopy annealing experiments are used to analyze the crystal structure, size and distribution of BaCl 2 nanocrystals in FCZ glass-ceramics as a function of annealing rate and temperature. Microstructural analysis of the early stages on nucleation identified the formation of both BaCl2 and BaF2 nanocrystals. Annealing FCZ glass-ceramics above 280°C can cause the formation of additional glass matrix phase crystals, their microstructure and the annealing parameters required for their growth are identified. As the crystalline phases grow directly from the glass, small variations in processing of the glass can have a profound influence on the crystallization process. The information obtained from these experiments improves the understanding of the nucleation, growth and phase transformation process of the BaCl¬2 nanocrystals and additional crystalline phases that form in FCZ glass-ceramics, and may help expedite the implementation of FCZ glass-ceramics as next-generation X-ray detectors. Lastly, as these glass-ceramics may one day be commercialized, an investigation into their degradation in different environmental conditions was also performed. The effects of direct contact with water or prolonged exposure to humid environments on the microstructure and the optical properties for FCZ glasses and glass-ceramics was explored.

  20. Extraction of Proteins Glass Bead Method For preparation of protein extracts, the glass bead method is preferred. Some researchers

    E-print Network

    Extraction of Proteins ­ Glass Bead Method For preparation of protein extracts, the glass bead. glass beads (106 micron glass bead, Sigma cat. No. G4649) 7. Tabletop centrifuge 8. Vortex 9 µl glass beads (106 micron glass beads, Sigma, cat. G4649). 8. Vortex at top speed for 5 minutes. 9