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1

Irradiation stability of R7T7-type borosilicate glass  

NASA Astrophysics Data System (ADS)

High-level nuclear waste containment glass is subjected to irradiation-induced stresses whose consequences must be assessed to guarantee the material behavior over time. Alpha decay from the minor actinides confined in the glass structure is responsible for most of the atom displacements. Minor actinide concentrations in the glass exceeding current levels are under consideration for future vitrification scenarios. Four R7T7-type borosilicate glass samples doped with 0.04, 0.4, 1.2 and 3.25 wt% 244CmO 2 were fabricated to study not only the cumulative effect of high alpha decay doses (>10 19 ?/g) but also of the dose rate. The homogeneity of the materials and their chemical compositions were characterized to ensure they were suitably representative for the experimental program. The macroscopic behavior of the glasses was characterized for doses up to 3 × 10 18 ?/g. No significant effect on the initial alteration rate was detected which means that the chemical reactivity of the glass with pure water is not affected by such levels of alpha doses. The glass swelled slightly depending on the dose, saturating at about 0.5% after receiving a dose of about 2 × 10 18 alpha disintegrations per gram of glass. The mechanical properties were observed to improve appreciably, with lower hardness but greater fracture toughness. A stabilization phenomenon comparable to that of the glass density was also observed. Comparing the experimental data with other findings obtained by atomistic modeling and external irradiation suggests that nuclear interactions caused by alpha decay recoil nuclei could be responsible for the experimental variations observed. The possible origins of the observed variations in macroscopic properties are also discussed.

Peuget, S.; Cachia, J.-N.; Jégou, C.; Deschanels, X.; Roudil, D.; Broudic, V.; Delaye, J. M.; Bart, J.-M.

2006-08-01

2

Helium mobility in SON68 borosilicate nuclear glass: A nuclear reaction analysis approach  

NASA Astrophysics Data System (ADS)

The 3He behavior in the non active R7T7 type borosilicate glass called SON68 has been investigated using the implantation method to introduce helium in the material. Nuclear Reaction Analysis (NRA) was performed to follow the helium concentration depth profile evolution as a function of annealing time and temperature. In addition, in situ Transmission Electron Microscopy (TEM) has been implemented to study the formation of helium bubbles during both implantation and annealing processes. Numerical modeling with two different approaches is proposed and discussed to investigate the helium mobility mechanisms. Our study reveals for helium incorporation by implantation at low temperature the presence of several helium populations with disparate diffusivities. The most mobile helium fraction would be attributed to atomic diffusion. The corresponding activation energy value (0.61 eV) extracted from Arrhenius graphs is in good agreement with literature data. The results also highlight that the damages associated to helium sursaturation are the source of small helium clusters formation, with a reduced mobility instead of the atomic mobility measured by the infusion technique. Small cavities that support this assumption have been observed by TEM at low temperature.

Bès, R.; Sauvage, T.; Peuget, S.; Haussy, J.; Chamssedine, F.; Oliviero, E.; Fares, T.; Vincent, L.

2013-11-01

3

Glasses for nuclear waste immobilization  

Microsoft Academic Search

Vitrification of nuclear wastes is attractive because of its flexibility, the large number of elements which can be incorporated in the glass, its high corrosion durability and the reduced volume of the resulting waste form. Vitrification is a mature technology and has been used for high level nuclear waste (HLW) immobilisation for more than 40 years in France, Germany and

M. I. Ojovan; O. G. Batyukhnova

2007-01-01

4

Natural analogues of nuclear waste glass corrosion.  

SciTech Connect

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.

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

1999-01-06

5

Crystallization during processing of nuclear waste glass  

SciTech Connect

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.

Hrma, Pavel R.

2010-12-01

6

Advances in processing nuclear waste glasses  

Microsoft Academic Search

The vitrification of nuclear waste glasses is presenting unique challenges to glass technologists. On the one hand, the composition of the most important constituent of the glass batch\\/--\\/the waste\\/--\\/may vary widely. On the other hand, the vitrification process itself must be tightly controlled to ensure product quality, public safety, and process reliability. This has led to several important developments in

Plodinec

1988-01-01

7

Nuclear waste glass interfaces after one year burial in STRIPA part 1: Glass/glass  

NASA Astrophysics Data System (ADS)

Two simulated nuclear waste glasses were corroded in an in-situ experiment in the STRIPA mine up to one year at 90°C. Changes in compositional in-depth profiles for glass/glass interfaces were measured using SIMS. Both glasses showed a depletion of Na, Cs, and B, but for the more corrosion resistant glass, the lower depletion depth is ascribed to the formation of a thin (2.0 m) coherent and dense outer layer, enriched in Mg, Ca, Sr, Ba, Zn-Al, Fe, and Si, which impedes both the ion exchange and network attack of the bulk glass underneath.

Hench, Larry L.; Lodding, Alexander; Werme, Lars

1984-08-01

8

Systems approach to nuclear waste glass development  

SciTech Connect

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.

Jantzen, C M

1986-01-01

9

Mechanical properties of nuclear waste glasses  

NASA Astrophysics Data System (ADS)

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.

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

2011-01-01

10

Mechanical properties of nuclear waste glasses  

Microsoft Academic Search

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

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

2011-01-01

11

Redox characterization of simulated nuclear waste glass  

Microsoft Academic Search

Ferrous\\/ferric equilibria were determined in an alkali-iron borosilicate glass of the type that is presently being considered for nuclear waste disposal. Theoretical redox behavior is found at conditions more reducing than 1 kPa. Deviation from this behavior at more oxidizing conditions results from mutual interactions between the iron redox couple and other multivalent ions in the glass. The results suggest

D. S. Goodman; D. W. Brite

1986-01-01

12

Glass vitrification of nuclear wastes  

Microsoft Academic Search

Bechtel has been retained by Du Pont to design and engineer the Defense Waste Processing Facility (DWPF) to vitrify high-level radioactive wastes. DWPF will collect the sludge from the bottom of storage tanks, wash it down and chemically neutralize it, and mix it with pulverized glass called frit, in a melter vessel where it becomes a molten homogeneous mass. The

1985-01-01

13

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 ...

14

Glass produced by underground nuclear explosions. [Rainier  

SciTech Connect

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.

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

1983-01-01

15

Nuclear Waste Glasses: Continuous Melting and Bulk Vitrification  

Microsoft Academic Search

This contribution addresses various aspects of nuclear waste vitrification. Composition of nuclear wastes varies in the number of components and their 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 that the glass is easily made and resists environmental degradation. Glass

Pavel R. Hrma; Albert A. Kruger

2009-01-01

16

NUCLEAR WASTE GLASSES CONTINUOUS MELTING AND BULK VITRIFICAITON  

Microsoft Academic Search

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

Pavel R. Hrma; Albert A. Kruger

2008-01-01

17

Iron Phosphate Glasses: An Alternative for Vitrifying Certain Nuclear Wastes  

Microsoft Academic Search

Vitrification of nuclear waste in a glass is currently the preferred process for waste disposal. DOE currently approves only borosilicate (BS) type glasses for such purposes. However, many nuclear wastes, presently awaiting disposal, have complex and diverse chemical compositions, and often contain components that are poorly soluble or chemically incompatible in BS glasses. Such problematic wastes can be pre-processed and\\/or

Delbert E. Day; Chandra S. Ray; Cheol-Woon Kim

2004-01-01

18

Thermodynamic model of natural, medieval and nuclear waste glass durability  

SciTech Connect

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.

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

1983-01-01

19

Irradiation effects in simplified nuclear waste glasses  

NASA Astrophysics Data System (ADS)

The structural evolution of simplified nuclear waste glasses under ?-irradiation (2.5 MeV) has been studied up to cumulated doses of the order of 10 9 Gy. A rapid saturation of the point defect creation is observed at a very low level (in large contrast with what is observed on pure silica). At large doses, we also observe an increase of the polymerization of the vitreous lattice, and the appearance of dissolved molecular oxygen, which however does not coalesce into bubbles. These evolutions can be linked with the diffusion of alkaline ions in the material. The effects of the glass composition (mixed alkali effect, specific role of some particular cations, which are known to block the structural evolution) have been also investigated in order to study the possibility of decreasing alkaline mobility under irradiation.

Boizot, Bruno; Ollier, Nadège; Olivier, Florent; Petite, Guillaume; Ghaleb, Dominique; Malchukova, Euguenia

2005-10-01

20

Simulation used to qualify nuclear waste glass for disposal  

Microsoft Academic Search

A hypothetical vitrification system was simulated to provide quantitative estimates of the errors associated with controlling and predicting the composition of the nuclear waste glass produced in the system. The composition of the glass must fall within certain limits in order to qualify for permanent geologic disposal. The estimated error in predicting the concentrations of various constituents in the glass

Paul W. Reimus; William L. Kuhn

1987-01-01

21

Compositional threshold for Nuclear Waste Glass Durability  

SciTech Connect

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.

Kruger, Albert A. [Pacific Northwest National Lab., Richland, WA (United States); Farooqi, Rahmatullah [Pohang Univ. of Science and Technology, (Korea, Republic of); Hrma, Pavel R. [Pacific Northwest National Lab., Richland, WA (United States), Pohang Univ. of Science and Technology, (Korea, Republic of)

2013-04-24

22

Spectroscopic investigation of U, Np and Th in nuclear glasses  

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

23

Chemical durability of simulated nuclear glasses containing water  

SciTech Connect

The chemical durability of simulated nuclear waste glasses having different water contents was studied. Results from the product consistency test (PCT) showed that glass dissolution increased with water content in the glass. This trend was not observed during MCC-1 testing. This difference was attributed to the differences in reactions between glass and water. In the PCT, the glass network dissolution controlled the elemental releases, and water in the glass accelerated the reaction rate. On the other hand, alkali ion exchange with hydronium played an important role in the MCC-1. For the latter, the amount of water introduced into a leached layer from ion-exchange was found to be much greater than that of initially incorporated water in the glass. Hence, the initial water content has no effect on glass dissolution as measured by the MCC-1 test.

Li, H. [Pacific Northwest Lab., Richland, WA (United States); Tomozawa, M. [Rensselaer Polytechnic Inst., Troy, New York (United States)

1995-04-01

24

Iron Phosphate Glasses: An Alternative for Vitrifying Certain Nuclear Wastes  

Microsoft Academic Search

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-approved borosilicate (BS) glasses. They include (1) a sodium bearing waste (SBW) at INEEL, (2) a high chrome

Day; E. Delbert; Chandra S. Ray; Cheol-Woon Kim; Wenhai Huang; Robert D. Leerssen; Signo T. Reis; Dongmei Zhu

2002-01-01

25

Iron Phosphate Glasses: An Alternative for Vitrifying Certain Nuclear Wastes  

SciTech Connect

Vitrification of nuclear waste in a glass is currently the preferred process for waste disposal. DOE currently approves only borosilicate (BS) type glasses for such purposes. However, many nuclear wastes, presently awaiting disposal, have complex and diverse chemical compositions, and often contain components that are poorly soluble or chemically incompatible in BS glasses. Such problematic wastes can be pre-processed and/or diluted to compensate for their incompatibility with a BS glass matrix, but both of these solutions increases the wasteform volume and the overall cost for vitrification. Direct vitrification using alternative glasses that utilize the major components already present in the waste is preferable, since it avoids pre-treating or diluting the waste, and, thus, minimizes the wasteform volume and overall cost.

Delbert E. Day; Chandra S. Ray; Cheol-Woon Kim

2004-12-28

26

Structural control of the stability of nuclear waste glasses  

NASA Astrophysics Data System (ADS)

Vitrification of liquid high-level radioactive waste in borosilicate glasses has received a great attention in several countries. The fundamental properties of the waste forms are their chemical and mechanical durability. We present an overview of the local structure of inactive analogs of the French nuclear glass, using structural information obtained by a combination of X-ray absorption Fine Structure (XAFS) and Wide Angle X-ray Scattering (WAXS). We will first contrast several classes of elements, such as Zr, Mo or Zn, which give nuclear glasses peculiar positive or adverse properties for the industrial process: enhanced chemical stability, phase separation, crystal nucleation and separation. These properties may be rationalized using Pauling rules, familiar to Mineralogists, as other properties are correctly modelled in simplified glass compositions using molecular dynamics. We will also point out the importance of the melt-to-glass transition and the consequence of the glass structural properties on the resistance of glassy matrices to irradiation. Glass alteration affects the long-term stability of the glass. It is characterized by an amorphous (glass)-amorphous (gel) transformation. Depending on alteration conditions, alteration layers may have or not a protective character, which will influence radionuclide retention over time. We will present the structural modification of the surface chemistry of the glass monoliths during short-term experiments and the evolution towards a gel, which forms progressively at the expense of the glass. The protective character of the gel, observed during glass leaching under near-saturated conditions, will be rationalized by its structural properties.

Calas, G.; Galoisy, L.; Cormier, L.; Bergeron, B.; Jollivet, P.

2009-05-01

27

Melting of foaming batches: Nuclear waste glass  

SciTech Connect

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.

Hrma, P.

1990-10-01

28

Rhenium solubility in borosilicate nuclear waste glass  

E-print Network

1 (1995). Hanford site secondary waste roadmap. PNNL-18196,Hanford site in Washington, the total amount of Tc in low activity waste (waste; technetium; rhenium; inductive coupled plasma; borosilicate glass 1. Introduction The Hanford site

McCloy, John S.

2014-01-01

29

NUCLEAR WASTE GLASSES CONTINUOUS MELTING AND BULK VITRIFICAITON  

SciTech Connect

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.

KRUGER AA; HRMA PR

2008-03-24

30

Immobilization of spent nuclear fuel in iron phosphate glass  

NASA Astrophysics Data System (ADS)

Twenty-four iron phosphate compositions (15 wt% wasteloading) were evaluated to determine their suitability for vitrifying Al-clad, highly enriched uranium, spent nuclear fuel (SNF). In half the compositions melted, 80 wt% of the Al 2O 3 in the simulated SNF was removed prior to vitrification. All twenty-four compositions formed homogeneous glasses, many at temperatures as low as 1150°C. As little as 2.5 wt% Na 2O decreased melt viscosity and increased alumina solubility in those glasses of higher alumina contents (7.2 wt% Al 2O 3). None of the glasses contained undissolved uranium compounds as has been found in borosilicate glasses containing as little 4.4 wt% UO 2. The chemical durability (measured by the product consistency test (PCT)) of the iron phosphate wasteforms is as good as, and in many cases up to 15 times better than the approved reference material (ARM-1) borosilicate glass.

Mesko, M. G.; Day, D. E.

31

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

SciTech Connect

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.

McKenzie, W.F.

1990-01-01

32

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

SciTech Connect

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.

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

1988-05-01

33

Leach tests at Savannah River Laboratory for radioactive and nonradioactive nuclear waste glasses  

Microsoft Academic Search

The high-level nuclear wastes currently stored at Savannah River Plant as caustic slurries will be immobilized into borosilicate glass. To characterize the glass resulting from this vitrification process, the Savannah River Laboratory (SRL) has developed and performed a variety of leach tests on both radioactive glass containing actual nuclear waste and nonradioactive glass containing simulated waste. These leach tests range

N. E. Bibler; C. M. Jantzen

1989-01-01

34

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

NASA Astrophysics Data System (ADS)

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.

Caurant, D.

2014-05-01

35

Redox of Simulated Nuclear Waste Glass Forming Melts  

SciTech Connect

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.

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

2001-12-01

36

Redox reaction and foaming in nuclear waste glass melting  

SciTech Connect

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.

Ryan, J.L.

1995-08-01

37

Helium solubility in SON68 nuclear waste glass  

SciTech Connect

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)

Fares, Toby; Peuget, Sylvain; Bouty, Olivier; Broudic, Veronique; Maugeri, Emilio; Bes, Rene; Jegou, Christophe [CEA, DEN, DTCD SECM LMPA, F-30207 Marcoule, Bagnols Sur Cez, (France); Chamssedine, Fadel; Sauvage, Thierry [CNRS, CEMHTI, F-245071 Orleans, (France); Deschanels, Xavier [LNAR, Marcoule Inst Separat Chem, F-30207 Bagnols Sur Ceze, (France)

2012-12-15

38

The ion exchange phase in corrosion of nuclear waste glasses  

NASA Astrophysics Data System (ADS)

The diffusion-controlled ion exchange phase in the corrosion of nuclear waste borosilicate glasses has been examined using the Doremus' model accounting for interdiffusion and exchange of the cations in the glass with protons from the water. Ion exchange is the principal radionuclide release mechanism for conditions when glass network hydrolysis is suppressed, such as in silica-saturated solutions when ion exchange may persist over geological time scales. In dilute aqueous solutions ion exchange controls the initial cation release and can dominate for tens and many hundreds of years if temperatures are low at low and neutral pH. Ion exchange rates are shown to have inverse square root time dependences, an Arrhenius-controlled temperature relationship and a 10 -0.5pH dependence with the pH of the contacting water. Due to radioactive decay the radionuclide releases from nuclear waste glasses are limited to certain upper values, which can be calculated based on available experimental data.

Ojovan, Michael I.; Pankov, Alexey; Lee, William E.

2006-11-01

39

Solid state diffusion during nuclear glass residual alteration in solution  

NASA Astrophysics Data System (ADS)

The long term alteration rate of the French R7T7 nuclear glass has been investigated since many years because this glass has been selected as radionuclide containment matrix in France. Recent studies have shown that this rate remains constant or is slightly decreasing with time. It never reaches zero. Although this long term rate is very low, only 5 nm per year at 323 K in initially pure water, it would be the dominant alteration phenomenon in a geological repository. Two mechanisms are suggested for explaining this long term behaviour: diffusion towards solution of elements from glass through an amorphous altered layer and precipitation of neoformed phases. Former studies showed that diffusion rates are in agreement with a solid state diffusion mechanism. Additional experiments in initially saturated silica water were performed in order to study the impact of various parameters on the values of the diffusion coefficient for mobile chemical elements: pH, temperature, ionic strength and S/ V ratio (glass surface area S to the solution volume V). The solutions and element profiles in altered glass were analysed by ICP-AES and TOF-SIMS, respectively. The results point out that S/ V and ionic strength are not key-parameters. pH leads to significant diffusion coefficient decrease at 323 K when it rises from 8 to 10. Variations with temperature can be modelled with an Arrhenius law. The calculated value of activation energy is discussed in comparison with literature data.

Chave, T.; Frugier, P.; Ayral, A.; Gin, S.

2007-05-01

40

Final technical report: Effects of water on properties of the simulated nuclear waste glasses  

Microsoft Academic Search

For isolation of nuclear wastes through the vitrification process, waste slurry is mixed with borosilicate based glass and remelted at high temperature. During these processes, water can enter into the final waste glass. It is known that water in silica and silicate glasses changes various glass properties, such as chemical durability, viscosity and electrical conductivity. These properties are very important

H. Li; M. Tomozawa

1996-01-01

41

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...

42

The remote handling of canisters containing nuclear waste in glass at the Savannah River Plant  

Microsoft Academic Search

The Defense Waste Processing Facility (DWPF) is a complete production area being constructed at the Savannah River Plant for the immobilization of nuclear waste in glass. The remote handling of canisters filled with nuclear waste in glass is an essential part of the process of the DWPF at the Savannah River Plant. The canisters are filled with nuclear waste containing

Callan

1986-01-01

43

Nuclear waste glass composition limitations. [Effects of reprocessing plant flowsheets on cost of vitrification  

Microsoft Academic Search

This paper discusses the primary considerations involved in nuclear waste glass composition development, explains why the maximum content of certain elements in those glasses is limited, and suggests some possible improvements in reprocessing and waste management practices that might reduce vitrification costs. The basic task is to formulate a glass that can be processed with an acceptably high waste loading

L. A. Chick; J. L. Swanson; D. S. Goldman

1984-01-01

44

A statistical approach for identifying nuclear waste glass compositions that will meet quality and processability requirements  

Microsoft Academic Search

Borosilicate glass provides a solid, stable medium for the disposal of high-level radioactive wastes resulting from the production of nuclear materials for United States defense needs. The glass must satisfy various quality and processability requirements on properties such as chemical durability, viscosity, and electrical conductivity. These properties depend on the composition of the waste glass, which will vary during production

Piepel

1990-01-01

45

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

DOEpatents

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.

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

1989-01-01

46

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

SciTech Connect

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.

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

1991-12-31

47

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

SciTech Connect

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.

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

1991-01-01

48

IRON PHOSPHATE GLASSES: AN ALTERNATIVE FOR VITRIFYING CERTAIN NUCLEAR WASTES  

SciTech Connect

During the past year, iron phosphate glasses containing the following three types of nuclear waste, as recommended by the Tank Focus Area (TFA) group, have been investigated. (1) a high sodium/sulfate Hanford Low-Activity Waste (LAW) (2) a High Chrome Waste (HCW) at Hanford, and (3) a Sodium Bearing Waste (SBW) at Idaho National Engineering and Environmental Laboratory (INEEL) Over three hundred trial melts, ranging in size from 50 g to more than 10 kg, have been evaluated. The experimental work consisted of (1) evaluating the melting behavior and characteristics, (2) measurement of the viscosity and electrical conductivity of promising melts over their melting range, (3) determining the chemical durability by the PCT and VHT methods of both glassy and partially crystallized iron phosphate wasteforms, (4) determining the solubility limit for chrome oxide in selected iron phosphate melts, (5) examining the feasibility of melting iron phosphate glasses by Cold Crucible Induction melting (CCIM), Hot Crucible Induction Melting (HCIM), and Microwave Melting, (6) and measuring the corrosion of Inconel 690 and 693, potential electrode materials, in an iron phosphate melt. In the past year, the results of the above experimental work have been described in eight technical papers and reports that have been submitted for publication.

Day, Delbert E.; Ray, Chandra S.; Kim, Cheol-Woon; Zhu, Dongmei

2003-06-13

49

Nuclear Magnetic Resonance Structural Studies of Barium Borosilicate Glasses, Fluorine-Doped Silicate Glasses, and Glasses Containing Selenium-Oxide and Mercuric -  

Microsoft Academic Search

The study of BaO-B_2O _3-SiO_2 glasses presented in this thesis utilizes ^{11} B and ^{29}Si nuclear magnetic resonance spectroscopy in measuring directly the amounts of boron species involved in tetrahedral and trigonal units as a function of BaO and SiO_2 contents. Analysis and interpretation of the data incorporates the use of a glass structure model which quantifies all borate and

Phillip Elton Stallworth

1989-01-01

50

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

DOEpatents

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.

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

1988-01-01

51

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

SciTech Connect

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.

Steefel, Carl

2014-01-06

52

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...

53

Surface layers on a borosilicate nuclear waste glass corroded in MgCl 2 solution  

Microsoft Academic Search

Surface layers on the French borosilicate nuclear waste glass, R7T7, corroded in MgCl2 solution were studied to determine the composition, structure and stability of crystalline phases. The characteristics of the phases constituting the surface layer varied with the parameter SV × t, the glass surface area (S) to solution volume (V) ratio, times time (t). At low SV × t

Abdesselam Abdelouas; Jean-Louis Crovisier; Werner Lutze; Bernd Grambow; Jean-Claude Dran; Regina Müller

1997-01-01

54

Photoluminescence investigations of rare earth (Eu and Gd) incorporated nuclear waste glass  

Microsoft Academic Search

Rare earth ion (Eu and Gd) bearing sodium-barium borosilicate glasses, used for vitrification of Trombay research rector nuclear waste were characterized by photoluminescence (PL) technique. This was done in order to identify the oxidation states and the coordination geometries of the ions in the glass matrix. It was observed that both the RE ions were stabilized in their 3+ oxidation

M. Mohapatra; R. K. Mishra; C. P. Kaushik; S. V. Godbole

2010-01-01

55

Nuclear waste vitrification in a ceramic-lined electric glass melter. [Federal Republic of Germany  

Microsoft Academic Search

Vitrification of high-level liquid waste from the nuclear fuel cycle in a liquid-fed electric glass melter is described with particular reference to the present status of the melter technology developed at the Institut fuer Nukleare Entsorgungstechnik (INE), Karlsruhe, West Germany. Based on available experience with simulated waste solutions. It is shown that electric melting of waste glass is a promising

Weisenburger

2009-01-01

56

Electrical Service and Controls for Joule Heating of a Nuclear Waste Experimental Glass Melter  

Microsoft Academic Search

Vitrification of radioactive liquid waste into glass is the best known method today for long-term storage of high radioactivity nuclear waste products. The electrical service and control system for an experimental electrically heated glass melter to handle nonradioactive materials, installed at Savannah River Laboratory, are described. Data accumulated and design and operating experience acquired in building and operating this melter

C. James Erickson; Abdul Q. Haideri

1985-01-01

57

Photoluminescence investigations of rare earth (Eu and Gd) incorporated nuclear waste glass  

Microsoft Academic Search

Rare earth ion (Eu and Gd) bearing sodium–barium borosilicate glasses, used for vitrification of Trombay research rector nuclear waste were characterized by photoluminescence (PL) technique. This was done in order to identify the oxidation states and the coordination geometries of the ions in the glass matrix. It was observed that both the RE ions were stabilized in their 3+ oxidation

M. Mohapatra; R. K. Mishra; C. P. Kaushik; S. V. Godbole

2010-01-01

58

Microstructures and leach rates of glass–ceramic nuclear waste forms developed by partial vitrification in a hot isostatic press  

Microsoft Academic Search

A high level nuclear waste calcine simulant is transformed to a dense and durable glass–ceramic waste form by addition of glass and crystal forming components, and hot isostatic pressing at 1000 °C and 138 MPa. The waste forms are abundantly composed of zircon, beddeyelite, apatite, fluorite, greenockite and boroaluminosilicate glass. The crystal nucleating, glass forming and volatilizing components of the

S. V. Raman

1998-01-01

59

An Alternative Host Matrix Based on Iron Phosphate Glasses for the Vitrification of Specialized Nuclear Waste Forms  

Microsoft Academic Search

Certain high level wastes (HLW) in the U.S. contain components such as phosphates, heavy metals, and halides which make them poorly suited for disposal in borosilicate glasses. Iron phosphate glasses appear to be a technically feasible alternative to borosilicate glasses for vitrifying these HLWs. The iron phosphate glasses mentioned above and their nuclear wasteforms are relatively new, so little is

Day; Delbert E

1999-01-01

60

Effects of Electron Irradiation in Nuclear Waste Glasses  

SciTech Connect

This article summarizes recent studies of electron irradiation damage in sodium borosilicate, iron phosphate and aluminophosphate glass waste forms using a modern analytical electron microscope. Three different borosilicate and iron phosphate glasses and an aluminophosphate glass were studied. Results indicate that all these glasses decomposed under the 200 kV electron irradiation. Migration of alkali elements from the irradiated centers to the peripheries under irradiation occurred in the alkali-element containing glasses, which results in the formation of alkali-depleted and -enriched phases. Formation of bubbles was only observed in the alkali-element containing iron phosphate and aluminophosphate glasses, not in the sodium borosilicate glasses when irradiated over a broad of dose rates. Separation of boron-rich phase from silicon-rich phase, iron-rich/aluminum-rich phase from phosphorous-rich domains were observed in the three types of glasses, respectively. Further irradiation resulted in formation of small particles. In the Fe-containing borosilicate glasses, the Fe is associated with the boron-rich phases after phase separation.

Sun, K; Wang, L M.; Ewing, Rodney C.; Weber, William J.

2005-02-01

61

West Valley high-level nuclear waste glass development: a statistically designed mixture study  

SciTech Connect

The first full-scale conversion of high-level commercial nuclear wastes to glass in the United States will be conducted at West Valley, New York, by West Valley Nuclear Services Company, Inc. (WVNS), for the US Department of Energy. Pacific Northwest Laboratory (PNL) is supporting WVNS in the design of the glass-making process and the chemical formulation of the glass. This report describes the statistically designed study performed by PNL to develop the glass composition recommended for use at West Valley. The recommended glass contains 28 wt% waste, as limited by process requirements. The waste loading and the silica content (45 wt%) are similar to those in previously developed waste glasses; however, the new formulation contains more calcium and less boron. A series of tests verified that the increased calcium results in improved chemical durability and does not adversely affect the other modeled properties. The optimization study assessed the effects of seven oxide components on glass properties. Over 100 melts combining the seven components into a wide variety of statistically chosen compositions were tested. Viscosity, electrical conductivity, thermal expansion, crystallinity, and chemical durability were measured and empirically modeled as a function of the glass composition. The mathematical models were then used to predict the optimum formulation. This glass was tested and adjusted to arrive at the final composition recommended for use at West Valley. 56 references, 49 figures, 18 tables.

Chick, L.A.; Bowen, W.M.; Lokken, R.O.; Wald, J.W.; Bunnell, L.R.; Strachan, D.M.

1984-10-01

62

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

SciTech Connect

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)

Pankov, Alexey S.; Ojovan, Michael I. [Immobilisation Science Laboratory, Department of Engineering Materials, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD (United Kingdom); Batyukhnova, Olga G. [International Education Training Centre, SUE SIA 'Radon', The 7-th Rostovsky Lane 2/14, Moscow, 119121 (Russian Federation); Lee, William E. [Department of Materials, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ (United Kingdom)

2007-07-01

63

A comparison of the performance of nuclear waste glasses by modeling  

SciTech Connect

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.

Grambow, B.; Strachan, D.M.

1988-12-01

64

THE IMPACT OF KINETICS ON NEPHELINE FORMATION IN NUCLEAR WASTE GLASSES  

SciTech Connect

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.

Amoroso, J.

2011-03-07

65

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

E-print Network

An Investigation into the Oxidation State of Molybdenum in Simplified High Level Nuclear Waste a full simulated HLW stream based upon 4:1 ratio of high burn up UO2/mixed oxide (HBU/MOX) fuel of Mo in glasses containing simplified simulated high level nuclear waste (HLW) streams has been

Sheffield, University of

66

Oxidation state of multivalent elements in high-level nuclear waste glass  

Microsoft Academic Search

Nuclear waste contains many different elements that have more than one oxidation state. When the nuclear waste is treated by vitrification, the behavior of the element in the melter and resulting glass product depends on the stable oxidation state. The stable oxidation state in any medium can be calculated from the standard potential in that medium. Consequently, the standard potential

J. G. Reynolds

2007-01-01

67

EELS Spectrum Imaging and Tomography Studies of Simulated Nuclear Waste Glasses  

SciTech Connect

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)

Yang, Guang; Saghi, Zineb; Xu, Xiaojing; Hand, Russell; Moebus, Guenter [Engineering Materials, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD (United Kingdom)

2007-07-01

68

Spectroscopic investigation of gamma radiation-induced coloration in silicate glass for nuclear applications  

NASA Astrophysics Data System (ADS)

Silicate glass irradiated by ?-rays was investigated in this study using spectroscopic analyses which included ultraviolet-visible (UV-Vis) absorption, electron paramagnetic resonance (EPR), and nuclear magnetic resonance (NMR). The phenomenon of coloration on ?-ray-irradiated silicate glass was analyzed and the effect of annealing on the silicate coloration was also investigated. The results revealed that the coloration originates from the creation of hole-centers (HC) caused by radiation. The shade of the coloration highly correlates to the amount of these HC-related defects but can be reversed by thermal annealing. The variation in coloration is an effective predictive factor in understanding radiation damage on silicate glass. Therefore, this study is relevant in the development of radiation detectors using silicate material as well as in the permanent disposal of high-level nuclear waste in glass form.

Tsai, Hsu-Sheng; Chao, Der-Sheng; Wu, Ya-Hsuan; He, Yu-Ting; Chueh, Yu-Lun; Liang, Jenq-Horng

2014-10-01

69

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

SciTech Connect

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.

Zapol, Peter (Argonne National Laboratory, Argonne, IL); Bourg, Ian (Lawrence Berkeley National Laboratories, Berkeley, CA); Criscenti, Louise Jacqueline; Steefel, Carl I. (Lawrence Berkeley National Laboratories, Berkeley, CA); Schultz, Peter Andrew

2011-10-01

70

Nuclear magnetic resonance (NMR) studies of the local structure of phosphorus chalcogenide glasses: an overview  

Microsoft Academic Search

An overview is given on recent nuclear magnetic resonance (NMR) structural studies of phosphorus chalcogenide glasses and melts. The detailed structural speciation of these systems has been derived on the basis of 31P dipolar spin-echo decay spectroscopy, magic-angle spinning (MAS), and variable temperature liquid-state NMR above the glass transition temperature. A specific feature in the binary phosphorus\\/chalcogen systems is the

Paul F. Mutolo; Michael Witschas; Guido Regelsky; Joern Schmedt auf der Guenne; H. Eckert

1999-01-01

71

Properties of nuclear waste melts and glasses: Contact-refractory corrosion and vapor phase hydration  

Microsoft Academic Search

Control of refractory corrosion in waste glass melts and meeting vapor phase hydration test (VHT) requirement for Hanford low-activity waste (LAW) glass product are two critical issues among many technical challenges of nuclear waste vitrification. In this study, refractory corrosion was treated as a complex non-equilibrium, multi-component and multi-phase reactive transport process and studied both thermodynamically and kinetically. Dissolution tests

Xiaodong Lu

2003-01-01

72

Glass matrices for immobilizing nuclear waste containing molybdenum and phosphorus  

NASA Astrophysics Data System (ADS)

Vitrification has been selected in France as the process for immobilizing high-level waste arising from spent fuel reprocessing. Some high-level solutions generated by reprocessing legacy fuel contain high molybdenum concentrations. Molybdenum is known to be sparingly soluble in conventional borosilicate glass, and work is in progress to find suitable glass formulations for such waste. The results of a basic study to identify borosilicate glasses composition zones of potential interest are discussed. A vast composition range was investigated by defining a fine mesh. The limits considered to delimit the range of the study were intentionally extended to identify formulations such as SiO 2-B 2O 3-Al 2O 3-Na 2O-P 2O 5 that are of interest for vitrifying molybdenum-rich waste. Observation of more than 50 tested mixtures revealed two composition zones of potential interest. One forms a homogeneous glass after melting at 1300 °C and rapid cooling; the other vitreous material comprises unconnected microbeads uniformly dispersed in a borosilicate glass.

Pinet, O.; Dussossoy, J. L.; David, C.; Fillet, C.

2008-07-01

73

Measurement of leaching from simulated nuclear-waste glass using radiotracers  

SciTech Connect

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.

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

1982-09-01

74

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

SciTech Connect

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.

Gin, Stephane [CEA Marcoule DTCD SECM LCLT, Bagnols/Ceze (France); Abdelouas, Abdessalam [SUBATECH, Nantes (France); Criscenti, Louise J. [Sandia National Laboratories, Albuquerque, NM (United States); Ebert, W. L. [Argonne National Laboratory (ANL), Argonne, IL (United States); Ferrand, Karine [SCK·CEN, Mol (Belgium); Geisler, Thorsten [Rheinische Friedrich-Wilhelms-Univ., Bonn (Germany); Harrison, Mike T. [National Nuclear Laboratory, Sellafield, Cumbria (United Kingdom); Inagaki, Yaohiro [Kyushu Univ. (Japan). Dept. Appl. Quantum Physics and Nuclear Engineering; Mitsui, Seiichiro [Japan Atomic Energy Agency, Ibaraki (Japan); Mueller, Karl T. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Environmental and Molecular Science Lab.; Marra, James C. [Savannah River National Laboratory, Aiken, SC (United States); Pantano, Carlo G. [Penn State Univ., State College, PA (United States); Pierce, Eric M. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Ryan, Joseph V. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Schofield, James M. [AMEC, Harwell Oxford (United Kingdom); Steefel, Carl I. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Earth Sciences Div.; Vienna, John D. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

2013-06-08

75

Deformation mechanisms during nanoindentation of sodium borosilicate glasses of nuclear interest  

SciTech Connect

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.

Kilymis, D. A.; Delaye, J.-M., E-mail: jean-marc.delaye@cea.fr [CEA Marcoule, DEN/DTCD, Service d’Etude et Comportement des Matériaux de Conditionnement, BP17171 30207 Bagnols-sur-Cèze Cedex (France)

2014-07-07

76

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...

77

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

SciTech Connect

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.

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

2013-06-01

78

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

SciTech Connect

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.

Mazer, J.J.

1993-12-31

79

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...

80

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

DOEpatents

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

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

1984-04-11

81

The determination of the Fe sup 2+ \\/Fe sup 3+ ratio in simulated nuclear waste glass by ion chromatography  

Microsoft Academic Search

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass in the Defense Waste Processing Facility (DWPF). In this facility, control of the oxidation\\/reduction (redox) equilibrium in the glass melter is critical for processing of the nuclear waste. Therefore, the development of a rapid and reliable analytical method for the determination of

Jantzen

1990-01-01

82

Photoluminescence investigations of rare earth (Eu and Gd) incorporated nuclear waste glass  

NASA Astrophysics Data System (ADS)

Rare earth ion (Eu and Gd) bearing sodium-barium borosilicate glasses, used for vitrification of Trombay research rector nuclear waste were characterized by photoluminescence (PL) technique. This was done in order to identify the oxidation states and the coordination geometries of the ions in the glass matrix. It was observed that both the RE ions were stabilized in their 3+ oxidation state in an asymmetric geometry. Spectral analysis of the Eu-glass was carried out to evaluate the J-O intensity parameters and various radiative properties such as radiative transition rate ( AR), radiative and non-radiative lifetimes ( ?R and ?NR) and luminescence branching ratio ( ?R). These properties suggested that amount of covalence existing between the rare earth ions and surrounding oxygens is relatively higher and there is existence of short range ordering in the glass.

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

2010-12-01

83

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

SciTech Connect

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.

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

2013-12-01

84

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

PubMed

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

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

85

Thermal and physicochemical properties important for the long term behavior of nuclear waste glasses  

NASA Astrophysics Data System (ADS)

High level nuclear waste from reprocessing of spent nuclear fuel has to be solidified in a stable matrix for safe long-time storage. Vitrification in borosilicate glasses is the technique accepted worldwide as the best combination of engineering constraints from fabrication and physicochemical properties of the matrix. A number of different glasses was developed in different national programs. The criteria and the reasons for selecting the final compositions are described briefly. Emphasis is placed on the French product R7T7 and on thermal and physicochemical properties though glasses developed in other national projects (e.g., the German product GP 98/12, etc.) are also treated. The basic physical and mechanical properties and the chemical durability of the glass in contact with water are described. The basic mechanisms of aqueous corrosion are discussed and the evolving modelling of the leaching process is dealt with, as well as effects of container material, backfill, etc. The thermal behavior has also been studied and extensive data exist on diffusion of glass constituents (Na) and of interesting elements of the waste such as the alkalis Rb and Cs or the actinides U and Pu, as well as on crystallization processes in the glass during storage at elevated temperatures. Emphasis is placed on the radiation stability of the glasses, based on extensive studies using short-lived actinides (e.g., 244Cm) or ion implantation to produce the damage expected during long storage at an accelerated rate. The radiation stability is shown to be very good, if realistic damage conditions are used. The knowledge accumulated in the past years is used to evaluate and predict the long-term evolution of the glass under storage conditions.

Matzke, Hj.; Vernaz, E.

86

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

SciTech Connect

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 (D6Li ? 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.

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

2014-12-01

87

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

SciTech Connect

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.

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

1987-12-01

88

Glass-Metal Joining in Nuclear Environment: The State of the Art  

Microsoft Academic Search

This article presents an overview of the different joining tech- nologies that can be used to join glass to metal in a severe nuclear environ- ment. Three different types of joining are discussed: fastening, liquid phase joining and solid phase joining. The article will conclude with a discussion on the best choices for the specific examplesof windows in the vacuum

M. Jacobs; Guido Van Oost; Joris Degrieck; Marc Decreton; Jochen Linke

89

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...

90

Nuclear Waste Vitrification in a Ceramic-Lined Electric Glass Melter  

Microsoft Academic Search

Vitrification of high-level liquid waste from the nuclear fuel cycle in a liquid-fed electric glass melter is described with particular reference to the present status of the melter technology developed at the Institut für Nukleare Entsorgungstechnik (INE), Karlsruhe, West Germany. Application of the process in an active plant to be built at the Eurochemic Site at Mol, Belgium, is outlined.

S. Weisenburger

1982-01-01

91

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

Microsoft Academic Search

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

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

1992-01-01

92

Interaction study between nuclear waste-glass melt and ceramic melter bellow liner materials  

Microsoft Academic Search

Identification of proper materials for plant scale vitrification furnaces, engaged in immobilization of high level nuclear waste has always been a great challenge. Fast degradation of pour spout materials very often cause problem towards smooth pouring of waste-glass melt in canister and damages bellow kept in between. The present experimental study describes the various reaction products that form due to

Pranesh Sengupta

2011-01-01

93

Oxidation state of multivalent elements in high-level nuclear waste glass  

SciTech Connect

Nuclear waste contains many different elements that have more than one oxidation state. When the nuclear waste is treated by vitrification, the behavior of the element in the melter and resulting glass product depends on the stable oxidation state. The stable oxidation state in any medium can be calculated from the standard potential in that medium. Consequently, the standard potential of multi-valent elements has been measured in many silicate-melts, including ones relevant to nuclear waste treatment. In this study, the relationship between the standard potential in molten nuclear waste glass and the standard potential in water will be quantified so that the standard potential of elements that have not been measured in glass can be estimated. The regression equation was found to have an R{sup 2} statistic of 0.96 or 0.83 depending on the number of electrons transferred in the reaction. The Nernst equation was then used to calculate the oxidation state of other relevant multi-valent elements in nuclear waste glass from these standard potentials and the measured ferrous to ferric iron ratio. The calculated oxidation states were consistent with all oxidation state measurements available. The calculated oxidation states were used to rationalize the behavior of many of the multi-valent elements. For instance, chromium increases glass crystallization because it is in the trivalent-state, iodine volatilises from the melter because it is in the volatile zero-valent state, and the leaching behavior of arsenic is driven by its oxidation state. Thus, these thermodynamic calculations explain the behavior of many trace elements during the vitrification process. (authors)

Reynolds, J.G. [Washington Group International, Richland, WA (United States)

2007-07-01

94

Surface layers on a borosilicate nuclear waste glass corroded in MgCl 2 solution  

NASA Astrophysics Data System (ADS)

Surface layers on the French borosilicate nuclear waste glass, R7T7, corroded in MgCl 2 solution were studied to determine the composition, structure and stability of crystalline phases. The characteristics of the phases constituting the surface layer varied with the parameter {S}/{V} × t , the glass surface area ( S) to solution volume ( V) ratio, times time ( t). At low {S}/{V} × t values (< 360 days/m; ? 36 d) th surface layer was thin and contained mainly iron hydroxide particles and hydrotalcite crystals. At an intermediate {S}/{V} × t value (2800 d/m; 5.5 y) the surface layer contained hydrotalcite-, chlorite- and saponite-type phases. At the highest {S}/{V} × t value (10 7 d/m; 463 d) the major phases were saponite, powellite, barite and cerianite solid solutions. About 95% of the uranium and > 98% of the neodymium released from the glass were precipitated in the surface layer. In the 463 day experiment, 86% of the neodymium in the surface layer was in solid solution with powellite, the rest with saponite. Uranium was contained exclusively in saponite. High {S}/{V} ratios, typical of disposal conditions for vitrified high-level radioactive waste, favor retention of actinides in fairly insoluble corrosion products. Observation of similar corrosion products on natural glasses as on nuclear waste glasses lend support to the hypothesis that the host phases for actinides observed in the laboratory are stable over geological periods of time.

Abdelouas, Abdesselam; Crovisier, Jean-Louis; Lutze, Werner; Grambow, Bernd; Dran, Jean-Claude; Müller, Regina

1997-01-01

95

Interaction study between nuclear waste-glass melt and ceramic melter bellow liner materials  

NASA Astrophysics Data System (ADS)

Identification of proper materials for plant scale vitrification furnaces, engaged in immobilization of high level nuclear waste has always been a great challenge. Fast degradation of pour spout materials very often cause problem towards smooth pouring of waste-glass melt in canister and damages bellow kept in between. The present experimental study describes the various reaction products that form due to interaction between waste-glass melt and potential bellow liner materials such as copper, stainless steel and nickel based Superalloys (Alloy 690, 625). The results indicate that copper based material has lesser tendency to form adherent glassy layer.

Sengupta, Pranesh

2011-04-01

96

Molecular Dynamics Simulation of Lead Borate and Related Glasses in Multicomponent Systems for Low Melting Vitrification of Nuclear Wastes  

NASA Astrophysics Data System (ADS)

Glasses based on lead oxide have excellent properties in general such as low melting point, high chemical durability and high stability of glassy form, which are suitable for the preservation of volatile nuclear wastes in a permanent vitrified form. In order to confirm the long-term performance of lead borate based glasses it is necessary to establish dissolution and diffusion processes based on a reliable model of the glass structure. In the present study molecular dynamics (MD) simulation of lead borate based glasses was carried out introducing a dummy negative point charge to reproduce asymmetric PbOn units. Parameters for the dummy charge were optimized based on the comparison between calculated radial distribution function and experimental one. Asymmetric coordination around Pb, for example trigonal bipyramid, was successfully reproduced in the MD simulated binary and ternary glass models. The simple model using the dummy charge was confirmed to be valid for further simulations of multicomponent glasses containing nuclear wastes and heavy elements.

Kato, S.; Sakida, S.; Benino, Y.; Nanba, T.

2011-03-01

97

Standard test methods for determining chemical durability of nuclear, hazardous, and mixed waste glasses and multiphase glass ceramics: The product consistency test (PCT)  

E-print Network

1.1 These product consistency test methods A and B evaluate the chemical durability of homogeneous glasses, phase separated glasses, devitrified glasses, glass ceramics, and/or multiphase glass ceramic waste forms hereafter collectively referred to as “glass waste forms” by measuring the concentrations of the chemical species released to a test solution. 1.1.1 Test Method A is a seven-day chemical durability test performed at 90 ± 2°C in a leachant of ASTM-Type I water. The test method is static and conducted in stainless steel vessels. Test Method A can specifically be used to evaluate whether the chemical durability and elemental release characteristics of nuclear, hazardous, and mixed glass waste forms have been consistently controlled during production. This test method is applicable to radioactive and simulated glass waste forms as defined above. 1.1.2 Test Method B is a durability test that allows testing at various test durations, test temperatures, mesh size, mass of sample, leachant volume, a...

American Society for Testing and Materials. Philadelphia

2002-01-01

98

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

E-print Network

distribution and speciation of Na, Mg, Ni and Cs in a simulated (inactive) nuclear waste glass were studied and Cs represent dose determining long-lived radionuclides (59 Ni, 135 Cs) in vitrified nuclear wasteNa, Mg, Ni and Cs distribution and speciation after long-term alteration of a simulated nuclear

99

Toward Understanding the Effect of Nuclear Waste Glass Composition on Sulfur Solubility  

DOE PAGESBeta

The concentration of sulfur in nuclear waste glass melter feed must be maintained below the point where salt accumulates on the melt surface. The allowable concentrations may range from 0.37 to over 2.05 weight percent (of SO3 on a calcined oxide basis) depending on the composition of the melter feed and processing conditions. If the amount of sulfur exceeds the melt tolerance level, a molten salt will accumulate, which may upset melter operations and potentially shorten the useful life of the melter. At the Hanford site, relatively conservative limits have been placed on sulfur loading in melter feed, which in turn significantly increases the amount of glass that will be produced. Crucible-scale sulfur solubility data and scaled melter sulfur tolerance data have been collected on simulated Hanford waste glasses over the last 15 years. These data were compiled and analyzed. A model was developed to predict the solubility of SO3 in glass based on 252 simulated Hanford low-activity waste (LAW) glass compositions. This model represents the data well, accounting for over 85% of the variation in data, and was well validated. The model was also found to accurately predict the tolerance for sulfur in melter feed for 13 scaled melter tests of simulated LAW glasses. The model can be used to help estimate glass volumes and make informed decisions on process options. The model also gives quantitative estimates of component concentration effects on sulfur solubility. The components that most increase sulfur solubility are Li2O > V2O5> CaO ? P2O5 > Na2O ? B2O3 > K2O. The components that most decrease sulfur solubility are Cl > Cr2O3 > Al2O3 > ZrO2 ? SnO2 > Others ? SiO2. The order of component effects is similar to previous literature data, in most cases.

Vienna, John D. [Pacific Northwest National Laboratory; Kim, Dong-Sang [Pacific Northwest National Laboratory; Muller, I. S. [The Catholic University National Laboratory; Kruger, Albert A. [Department of Energy -- Ofice of River Protection; Piepel, Gregory F. [Pacific Northwest National Laboratory

2014-10-01

100

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

SciTech Connect

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.

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

101

Environment and oxidation state of molybdenum in simulated high level nuclear waste glass compositions  

NASA Astrophysics Data System (ADS)

Alkali borosilicate glasses containing between 20 and 35 wt% of a simulated high level nuclear waste stream with varying Li 2O contents were melted under neutral (air) and reducing (nitrogen/hydrogen) conditions. XRD analysis of the as-cast glasses showed a tendency for the products to remain amorphous when melted under neutral conditions and for metallic silver to develop in the reduced melts. EXAFS analysis revealed (MoO 4) 2- tetrahedra in all glasses regardless of the sparge applied during melting. The glasses were heat treated to simulate an interruption to the cooling system used to prevent heat build-up in the vitrified product store. Powellite-type molybdate phases were found to develop in the heat treated samples and formed at lower waste loadings in glasses sparged with a reducing gas. A reduction in the quantity of Li 2O lead to a reduction in the quantity of powellite-type molybdate phases. EDS showed the primary molybdate phase to be high in Sr and rare earth elements and TEM indicated that the presence of silver metal encouraged molybdate formation.

Short, R. J.; Hand, R. J.; Hyatt, N. C.; Möbus, G.

2005-04-01

102

Properties of nuclear waste melts and glasses: Contact-refractory corrosion and vapor phase hydration  

NASA Astrophysics Data System (ADS)

Control of refractory corrosion in waste glass melts and meeting vapor phase hydration test (VHT) requirement for Hanford low-activity waste (LAW) glass product are two critical issues among many technical challenges of nuclear waste vitrification. In this study, refractory corrosion was treated as a complex non-equilibrium, multi-component and multi-phase reactive transport process and studied both thermodynamically and kinetically. Dissolution tests of granular refractory materials into under-saturated melts coupled with crystallization tests from supersaturated melts were used to determine the possible equilibrium points. The test results show that spinet phase is the most stable phase of K-3 refractory. Solubility of glass-refractory interface material controls the long term refractory corrosion rate and protects refractory from further corrosion. Therefore, refractory corrosion rate can be possibly adjusted by controlling the underlying solubility of the interface material. A set of monolithic refractory corrosion and dissolution tests was carried out to study the kinetic effects of refractory porosity and glass melt viscosity, the two major kinetic factors associated with reactive transport process. The test results show that temperature and glass melt viscosity have intensive effects on refractory material dissolution rate. Fast closure of channels near the glass-refractory interface during corrosion reaction by fast transformation of solid solution to spinel and spinel re-crystallization helps stop further corrosion reaction. Glass composition can be "passivated" by engineering the formulation to maximizing the beneficial alteration process. For the study of VHT kinetics, data from simulated LAW glasses studied previously at Pacific Northwest National Laboratory and Vitreous State Laboratory was modeled based on Avrami equation and its variant, the so-called generalized Avrami equation for better modeling of the VHT data. The results show that the kinetics of the complex vapor hydration process is described satisfactorily by the generalized Avrami equation. The generalized Avrami equation allows the characterization of vapor phase hydration data obtained at different times and temperatures quantitatively on a common basis. The three parameters associated with the generalized Avrami equation depend strongly on glass composition. It seems that both compositional mismatch and incompatibility of a host glass to the transformed hydrous crystalline phases slow down the vapor hydration rate.

Lu, Xiaodong

103

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 ...

104

Molecular Dynamics Simulation of Lead Borate and Related Glasses in Multicomponent Systems for Low Melting Vitrification of Nuclear Wastes  

Microsoft Academic Search

Glasses based on lead oxide have excellent properties in general such as low melting point, high chemical durability and high stability of glassy form, which are suitable for the preservation of volatile nuclear wastes in a permanent vitrified form. In order to confirm the long-term performance of lead borate based glasses it is necessary to establish dissolution and diffusion processes

S. Kato; S. Sakida; Y. Benino; T. Nanba

2011-01-01

105

A fractured roman glass block altered for 1800 years in seawater: Analogy with nuclear waste glass in a deep geological repository  

NASA Astrophysics Data System (ADS)

Fractured archaeological glass blocks altered 1800 years in seawater are investigated because of their morphological analogy with vitrified nuclear waste. They provide an opportunity for understanding glass alteration in variable confined media (cracks), by studying an actual ancient system in a known stable natural environment. Characterization of the crack network from two-dimensional trace maps (length, alteration thickness, orientation) allows us to determine the three-dimensional geometric parameters (crack density, fracture ratio) and the percentage of alteration, using stereological relations. This methodology could be applied to nuclear glass. From a representative archaeological glass block, we showed that the surface developed by the cracks is 86 ± 27 times greater than the geometric surface but the volumetric alteration is 12.2 ± 4.1%, which is only 12 times greater than the volumetric alteration of the block periphery (about 1 vol%). This unexpected low value is explained by the large variation of the alteration thicknesses in the different types of cracks in relation with their location in the block. The alteration thickness is usually smaller in the internal zone than in the border zone. The alteration layers resulted from three main mechanisms (interdiffusion, glass dissolution, and secondary phase precipitation) leading to two different alteration products (a sodium-depleted layer and mainly a Mg-smectite). Geometric parameters such as the glass surface area/solution volume ratio and transport parameters (renewal of the alteration solution) strongly affected the glass dissolution kinetics. The confined conditions and the diffusive transport of reactive species favor low alteration kinetics. The precipitation of secondary phases also results in sealing of the cracks. Consequently, although it is not known if subcritical crack growth occurred, internal cracks account for only a minor contribution to the overall alteration. These results improve our understanding of alteration in cracks for assessing the predominant physical and chemical parameters that must be considered in long-term nuclear glass modeling.

Verney-Carron, Aurelie; Gin, Stephane; Libourel, Guy

2008-11-01

106

An alternative host matrix based on iron phosphate glasses for the vitrification of specialized nuclear waste forms. 1998 annual progress report  

Microsoft Academic Search

'Certain high level wastes (HLW) in the US contain components such as phosphates, heavy metals, and halides which make them poorly suited for disposal in borosilicate glasses. Iron phosphate glasses appear to be a technically feasible alternative to borosilicate glasses for vitrifying these HLWs. The iron phosphate glasses mentioned above and their nuclear wasteforms are relatively new, so little is

D. E. Day; C. S. Ray; G. K. Marasinghe; M. Karabulut; X. Fang

1998-01-01

107

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

SciTech Connect

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.

Mazer, J.J.; Bates, J.K.; Bradley, C.R. [Argonne National Lab., IL (United States); Stevenson, C.M. [Archaeological Services Consultants, Inc., Columbus, OH (United States)

1991-11-01

108

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

SciTech Connect

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.

Laverty, B.R.

1987-10-02

109

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

E-print Network

, vitrification of high level nuclear waste is currently undertaken at the Sellafield Waste Vitrification PlantTHE 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

Sheffield, University of

110

Interstitial sites for He incorporation in nuclear glasses and links to the structure: Results from numerical investigation  

NASA Astrophysics Data System (ADS)

To investigate rare gases incorporation in glasses in relation with nuclear waste confinement, a wide range of borosilicate glasses have been studied by means of molecular dynamics simulations. The rare gases solubility is related to the number of interstitial sites accessible for these gases. To elucidate any relation between the number of interstitial sites and the glass composition, a large set of glass compositions that contain the most representative components in nuclear glasses is considered. We are mainly interested in SBN glasses (SiO2-B2O3-Na2O). A composition dependent force field was used to model the interactions between the atoms. Delaunay tessellation method was used to characterize the different topologies accessible for rare gases and analyze the interstitial sites distribution. In order to investigate irradiation effects by nuclear energy deposition on the number of interstitial sites accessible for He, disordered glasses representative of structures submitted to series of displacement cascades, were prepared by modifying the preparation procedure and the number of interstitial site changes were analyzed.

Kerrache, Ali; Delaye, Jean-Marc

2014-05-01

111

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

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.

Raman, Swaminathan Venkat

2002-11-01

112

Toward Understanding the Effect of Nuclear Waste Glass Composition on Sulfur Solubility  

SciTech Connect

The concentration of sulfur in nuclear waste glass melter feed must be maintained below the point where salt accumulates on the melt surface. The allowable concentrations may range from 0.37 to over 2.05 weight percent (of SO3 on a calcined oxide basis) depending on the composition of the melter feed and processing conditions. If the amount of sulfur exceeds the melt tolerance level, a molten salt will accumulate, which may upset melter operations and potentially shorten the useful life of the melter. At the Hanford site, relatively conservative limits have been placed on sulfur loading in melter feed, which in turn significantly increases the amount of glass that will be produced. Crucible-scale sulfur solubility data and scaled melter sulfur tolerance data have been collected on simulated Hanford waste glasses over the last 15 years. These data were compiled and analyzed. A model was developed to predict the solubility of SO3 in glass based on 252 simulated Hanford low-activity waste (LAW) glass compositions. This model represents the data well, accounting for over 85% of the variation in data, and was well validated. The model was also found to accurately predict the tolerance for sulfur in melter feed for 13 scaled melter tests of simulated LAW glasses. The model can be used to help estimate glass volumes and make informed decisions on process options. The model also gives quantitative estimates of component concentration effects on sulfur solubility. The components that most increase sulfur solubility are Li2O > V2O5> CaO ? P2O5 > Na2O ? B2O3 > K2O. The components that most decrease sulfur solubility are Cl > Cr2O3 > Al2O3 > ZrO2 ? SnO2 > Others ? SiO2. The order of component effects is similar to previous literature data, in most cases.

Vienna, John D. [Pacific Northwest National Laboratory; Kim, Dong-Sang [Pacific Northwest National Laboratory; Muller, I. S. [The Catholic University National Laboratory; Kruger, Albert A. [Department of Energy -- Ofice of River Protection; Piepel, Gregory F. [Pacific Northwest National Laboratory

2014-10-01

113

Model for the conversion of nuclear waste melter feed to glass  

SciTech Connect

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.

Pokorny, Richard [Inst. of Chemical Technology Prague (Czech Republic). Dept. of Chemical Engineering; Hrma, Pavel R. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Pohang Univ. of Science and Technology, Pohang (Korea, Republic of). Division of Advanced Nuclear Engineering

2014-01-23

114

Model for the conversion of nuclear waste melter feed to glass  

NASA Astrophysics Data System (ADS)

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.

Pokorny, Richard; Hrma, Pavel

2014-02-01

115

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

NASA Astrophysics Data System (ADS)

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.

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

2010-06-01

116

A two-dimensional deuterium nuclear magnetic resonance study of molecular reorientation in sugar\\/water glasses  

Microsoft Academic Search

Two-dimensional nuclear magnetic resonance time domain analysis of the stimulated echo experiment is used to study the molecular reorientation of deuterated glucose molecules in a glucose\\/water glass at about 15 °C above the glass transition. By measuring both the cos-cos and sin-sin two-time single particle correlation functions it is shown that the reorientation is isotropic, which enables the determination of

Andrew M. Wachner; Kenneth R. Jeffrey

1999-01-01

117

Identification of a Secondary Crystallized Phase formed during Nuclear Glasses Leaching - Effect of the Leached Glass Composition  

NASA Astrophysics Data System (ADS)

Silicate glass leaching in a unrenewed aqueous solution leads to gel formation at the glass water interface. This amorphous hydrated layer sometimes behaves like a diffusion barrier: the glass alteration rate decreases according to an inverse square root of time equation. In the case of Mg-containing glasses, the alteration rate usually remains quasi constant and seems to be controlled by the growth of secondary crystallized phases. These phases consume elements from solution. They can sustain gel dissolution inducing a decrease of its passivating properties. Long-term behaviour modelling of Mg-containing glasses designed for the confinement of fission products (AVM glasses, Atelier de vitrification de Marcoule, France) first requires a precise identification of these Mg-rich phases. Experimental investigations were performed on several glass samples using X-ray diffraction (XRD), 27Al and 29Si MAS NMR and elemental chemical analysis. Aluminous hectorite Na0.45(Mg2.28Li0.11Al0.39Fe0.06M0.16)(Si3.21Al0.79)O10(OH)2, with M being a divalent cation, was identified. 25 glasses were required for a full representation in term variations of AVM glasses composition range. Their residual alteration rates were proved to significantly depend on glass composition since a one order of magnitude difference was measured between the less and the most altered glasses. Nevertheless, the same crystallized phase was evidenced whatever the glass composition and whatever the initial composition of the solution (pure water or Mg-rich groundwater). Only a shift of the (060) peak between 1.521 and 1.530 Å was evidenced. It can be attributed to slight composition variations. Relations between the glass magnesium fraction, the amount of precipitated hectorite, the residual rate, and the measured pH are not obvious. However, hectorite precipitation was proved to depend on pH, being favoured between pH50°C 9 and 9.5. Moreover, the higher the amount of precipitated hectorite, the lower the solution pH. Self regulation of hectorite precipitation evidences that all mechanisms involved are strongly interdependent.

Thien, Bruno; Godon, Nicole; Frugier, Pierre; Gin, Stéphane; Ayral, André

2010-05-01

118

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

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.

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

2013-06-01

119

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

SciTech Connect

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.

Wronkiewicz, D.J.; Bates, J.K.; Buck, E.C.; Hoh, J.C.; Emery, J.W. [Argonne National Lab., IL (United States). Chemical Technology Div.; Wang, L.M. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Geology

1997-07-01

120

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

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

Sheffield, University of

121

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

NASA Astrophysics Data System (ADS)

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.

Wang, Chuan

122

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

SciTech Connect

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{sup ?9} to 10{sup ?5} s) and a scattering vector Q range (9.6–40 nm{sup ?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{sub c} in the mode coupling theory. The results suggest the important roles of hopping motions below T{sub 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.

Kanaya, Toshiji; Inoue, Rintaro [Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011 (Japan)] [Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011 (Japan); Saito, Makina [Elettra-Sincrotrone Trieste, S. S. 14 Km 163.5, I-34149 Trieste (Italy)] [Elettra-Sincrotrone Trieste, S. S. 14 Km 163.5, I-34149 Trieste (Italy); Seto, Makoto [Research Reactor Institute, Kyoto University, Kumatori, Osaka-fu 590-0494 (Japan)] [Research Reactor Institute, Kyoto University, Kumatori, Osaka-fu 590-0494 (Japan); Yoda, Yoshitaka [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo-ken 679-5198 (Japan)] [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo-ken 679-5198 (Japan)

2014-04-14

123

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

SciTech Connect

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.

Bock, D.; Kahlau, R.; Pötzschner, B.; Körber, T.; Wagner, E.; Rössler, E. A., E-mail: ernst.roessler@uni-bayreuth.de [Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth (Germany)

2014-03-07

124

Silicate Glasses In Nuclear Harsh Environment: Application Of Thermostimulated Luminescence To Radiation Damage Study  

NASA Astrophysics Data System (ADS)

It is well known that when a silica optical fiber is irradiated by neutrons or heavy ions, there is an attenuation of the transmission of the signal which is due to the creation of specific radiation damage. We have been able to show the creation of alpha radiation damage in borosilicate glass and glass used for radioactive waste confining in studying their properties of thermostimulated luminescence after high alpha irradiation. We have been able to correlate these radiation damages with interatomic bond break which implies oxygen. To extend this research to all silica optical fiber, the thermostimulated luminescence mechanisms of vitreous silica have been analysed. To exalt its properties in thermostimulated luminescence it has been doped with aluminium. Then, the creation of alpha radiation damage has been searched in this vitreous silica doped with aluminium. The next step of the study is an extending of this method to detect the effect of neutronic or heavy ions irradiation on vitreous silica samples which constitutes the basic material of optical fiber used in nuclear harsh environment.

Kersey, A. D.; Dandridge, A.; Tveten, A. B.

1989-04-01

125

Elemental depth profiling of nuclear waste glasses after two-years burial in a salt geology  

SciTech Connect

This paper reports that detailed surface compositional analysis has been conducted on 12 simulated nuclear waste forms leached for two years in the brine environment of the Waste Isolation Pilot Plant (WIPP). Secondary ion mass spectrometry (SIMS) of both cations and anions has identified characteristic leaching and precipitation zones within the leached layers on all specimens. The thickness of the leached layer is found to range from approximately 0.3 to 2.7 [mu]m and the total element loss from 80 to 625 mmol/m[sup 2], indicating that durability in brine differs by less than an order of magnitude between the different glasses. The in-depth profiles of anionic elements indicate the significant roles of carbon, fluorine, and chlorine in the formation of surface phases. Also recorded and discussed are elemental SIMS images of sputter crater tapers, providing additional documentation of leaching subzones.

Lodding, A.R.; Engstrom, E.U. (Chalmers Univ. of Technology, Goeteborg (Sweden). Inst. of Physics); Zoitos, B.K.; Clark, D.E. (Florida Univ., Gainesville, FL (United States). Dept. of Materials Science and Engineering); Wicks, G.G. (Savannah River Lab., Aiken, SC (United States))

1992-10-01

126

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

SciTech Connect

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.

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

1987-12-01

127

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

Microsoft Academic Search

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

Jantzen

1991-01-01

128

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

NASA Technical Reports Server (NTRS)

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.

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

1971-01-01

129

Nuclear radiation-induced changes in strength and mechanical properties of glass  

Microsoft Academic Search

In order to establish whether the glass structure is related to its strength at the various irradiations, both the effect of the thermal prehistory of the glass and that of the imperfect (weakened) surface layer were examined. Examined were samples of well annealed and thermally toughened glass (toughened in the liquid polyethyl siloxanes PES-1, PES-4, and PES-5) with the usual

S. I. Sil'vestrovich; T. A. Plisko

1968-01-01

130

Optimization of glass composition for the vitrification of nuclear waste at the Savannah River plant  

Microsoft Academic Search

Waste glasses of different compositions were compared in terms of leachability, viscosity, liquidus temperature, and coefficient of expansion. The compositions of the glasses were determined by statistical optimization. Waste glass of the optimized composition is more durable than the current reference composition but can still be processed at low temperature.

P. D. Soper; L. F. Lighter; M. J. Plodinec; G. J. Roberts; D. D. Walker

1983-01-01

131

Optimization of glass composition for the vitrification of nuclear waste at the Savannah River Plant  

Microsoft Academic Search

Waste glasses of different compositions were compared in terms of leachability, viscosity, liquidus temperature, and coefficient of expansion. The compositions of the glasses were determined by statistical optimization. Waste glass of the optimized composition is more durable than the current reference composition but can still be processed at low temperature.

P. D. Soper; G. J. Roberts; L. F. Lightner; D. D. Walker; M. J. Plodinec

1982-01-01

132

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

PubMed

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

Sengupta, Pranesh

2012-10-15

133

Investigation of alkali ion exchange processes in waste glasses using Rutherford backscattering spectrometry and nuclear reaction analysis  

NASA Astrophysics Data System (ADS)

A series of dissolution experiments using isotopic labeled (D2 18O) aqueous solution were carried out to investigate the ion exchange mechanism in Na2O-Al2O3-SiO2 glasses with fixed Na2O and variable Al2O3 concentrations. The sodium removal and the deuterium and oxygen uptake in the glass coupons were measured using ion beam methods such as Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Both RBS and NRA experimental spectra were simulated using the SIMNRA simulation code with a thin layer approximation. Na, D, and 18O concentrations as a function of depth in reacted and non-reacted glasses were determined using simulated spectra. On the basis of the depth distributions of these elements, three different zones (reaction, transition, and diffusion zones) were identified in both samples.

Shutthanandan, V.; Thevuthasan, S.; Baer, D. R.; Adams, E. M.; Maheswaran, S.; Engelhard, M. H.; Icenhower, J. P.; McGrail, B. P.

2001-07-01

134

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

SciTech Connect

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.

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

2010-11-23

135

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

E-print Network

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

Sheffield, University of

136

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

SciTech Connect

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.

Fox, K.; Edwards, T.

2012-01-11

137

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

SciTech Connect

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.

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

2008-09-15

138

Analytical electron microscopy study of colloids from nuclear waste glass reaction  

SciTech Connect

An Analytical Electron Microscopy study of colloidal particles formed during reaction of wste glass has been performed. The effect of waste glass test parameters on colloid formation is examined. Characterization of phases present in the leachate of these tests has shown that layers spalled from the glass and precipitated phases are both sources of colloids in the leachate. Elements, such as uranium, have been found to concentrate within colloidal particles in the leachate.

Buck, E.C.; Bates, J.K.; Cunnane, J.C.; Ebert, W.L.; Feng, X.; Wronkiewicz, D.J.

1992-01-01

139

Analytical electron microscopy study of colloids from nuclear waste glass reaction  

SciTech Connect

An Analytical Electron Microscopy study of colloidal particles formed during reaction of wste glass has been performed. The effect of waste glass test parameters on colloid formation is examined. Characterization of phases present in the leachate of these tests has shown that layers spalled from the glass and precipitated phases are both sources of colloids in the leachate. Elements, such as uranium, have been found to concentrate within colloidal particles in the leachate.

Buck, E.C.; Bates, J.K.; Cunnane, J.C.; Ebert, W.L.; Feng, X.; Wronkiewicz, D.J.

1992-12-31

140

CRYSTALLIZATION IN MULTICOMPONENT GLASSES  

SciTech Connect

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.

KRUGER AA; HRMA PR

2009-10-08

141

The relationship between glass viscosity and composition: A first principles model for vitrification of nuclear waste  

Microsoft Academic Search

540The Defense Waste Processing Facility will incorporate high-level liquid waste into borosilicate glass for stabilization and permanent disposal in a geologic repository. The viscosity of the melt determines the rate of melting of the raw feed, the rate of gas bubble release due to foaming and fining, the rate of homogenization, and thus, the quality of the glass produced. The

Jantzen

1990-01-01

142

The relationship between glass viscosity and composition: A first principles model for vitrification of nuclear waste  

Microsoft Academic Search

The Defense Waste Processing Facility will incorporate high-level liquid waste into borosilicate glass for stabilization and permanent disposal in a geologic repository. The viscosity of the melt determines the rate of melting of the raw feed, the rate of gas bubble release due to foaming and fining, the rate of homogenization, and thus, the quality of the glass produced. The

Jantzen

1990-01-01

143

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

SciTech Connect

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.

Jantzen, C.M.

1991-01-01

144

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

SciTech Connect

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.

Jantzen, C.M.

1991-12-31

145

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

NASA Astrophysics Data System (ADS)

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.

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

2010-05-01

146

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

SciTech Connect

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.

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

147

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

SciTech Connect

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.

Gin, Stephane [French Atomic Energy Commission (CEA); Abdelouas, Abdesselam [SUBATECH Laboratory (France); Criscenti, Louise J [Sandia National Laboratory (SNL); Ebert, William L [Argonne National Laboratory (ANL); Ferrand, K [Belgian Nuclear Research Centre, SCK-CEN; Geisler, T [Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany; Harrison, Michael T [National Nuclear Laboratory (NNL); Inagaki, Y [Kyushu University, Japan; Mitsui, S [Japan Atomic Energy Agency (JAEA); Mueller, K T [Pacific Northwest National Laboratory (PNNL); Marra, James C [Savannah River National Laboratory (SRNL), Aiken, S.C.; Pantano, Carlo G [Pennsylvania State University, State College, PA; Pierce, Eric M [ORNL; Ryan, Joseph V [Pacific Northwest National Laboratory (PNNL); Schofield, J M [AMEC, Harwell Oxford Didcot Oxfordshire, United Kingdom; Steefel, Carl I [Lawrence Berkeley National Laboratory (LBNL); Vienna, John D. [Pacific Northwest National Laboratory (PNNL)

2013-01-01

148

Development of Vitrification Process and Glass Formulation for Nuclear Waste Conditioning  

SciTech Connect

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.

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

2002-02-26

149

X-ray photoelectron spectroscopy and nuclear magnetic resonance structural study of phosphorus oxynitride glasses, ‘LiNaPON’  

Microsoft Academic Search

In this study, the structure of mixed alkali nitrided phosphate glasses ‘LiNaPON’, of composition Li0.5Na0.5PO3?3x\\/2Nx(0nuclear magnetic resonance (NMR) spectroscopies. XPS results show that nitrogen N3? exists as two-coordinated –N? atoms and three-coordinated –N? atoms, respectively bonded to two and three phosphorus atoms, thus

André Le Sauze; Lionel Montagne; Gérard Palavit; Franck Fayon; Roger Marchand

2000-01-01

150

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

SciTech Connect

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.

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

1996-02-01

151

Alteration of a basaltic glass in an argillaceous medium:. The Salagou dike of the Lodève Permian Basin (France). Analogy with an underground nuclear waste repository  

NASA Astrophysics Data System (ADS)

Volcanic basaltic glasses are commonly considered to be very suitable natural analogs of vitrified waste packages intended for geological disposal. The studied basaltic glass of the Salagou dike (Lodève Basin, France) intruded into a Permian argillaceous formation about 1.4 Ma ago, provides a means of assessing the long-term behavior of nuclear waste glass in an argillaceous repository concept. This study is based on combining chemical, mineralogical and isotopic investigations. The occurrence of a palagonite film no more than 1.2 mm thick characterizes the basaltic glass alteration in contact with the argillaceous host rock. The chemical and structural properties of the palagonite suggest constant volume alteration. The alteration rates estimated from palagonite thickness and age of the glass are comparable to those measured on natural glasses altered in nonargillaceous media. The occurrence of the studied argillaceous material in contact with the basaltic glass did not result in long-term alteration kinetics significantly different from those measured in simple glass/water systems. Mineralogical, chemical, and isotopic data obtained on the basaltic and argillaceous components suggest that an aqueous fluid flowed primarily at the glass/argillite interface and did not propagate in the argillaceous host rock beyond 5 cm from the basaltic dike. The elements released by alteration of the basaltic glass - notably strontium - did not diffuse into the surrounding clay. This conclusion is important from the perspective of a natural analog for a deep geological repository for nuclear waste, and highlights the major role of the structural properties of the clayey barrier.

Techer, Isabelle; Lancelot, Joël; Clauer, Norbert; Liotard, Jean Michel; Advocat, Thierry

2001-04-01

152

Thermodynamics and kinetics of crystallization of near-liquidus crystalline phases in defense nuclear waste glass melts  

NASA Astrophysics Data System (ADS)

Vitrification has been identified as the primary mode of nuclear waste immobilization. Two important factors that affect the economic success of the vitrification program are waste loading and melter life. High-level nuclear waste (HLW) streams often contain significant amounts of Fe, Ni, Mn and Cr. Some of these waste streams contain significant amounts of Zr, Th & U. This often leads to the crystallization of iron-chrome spinels or oxides/silicates of Zr, Th and U as the near-liquidus phases. The waste loading that can be achieved is often limited by crystallization of these near-liquidus phases. The settling of these phases can reduce the melter life. Hence understanding the crystallization of these crystalline phases is important in predicting the behavior of the HLW glasses in the melter environment. Representative HLW glasses were selected and heat treated at different temperatures and times. The compositions of the glassy phase, composition, morphology and volume fraction of the crystalline phases have been analyzed to understand thermodynamics and kinetics of crystallization of these near liquidus phases. The spinel compounds observed in HLW glasses exhibit extensive solid solution ranges depending on the temperature and glass composition, with Cr/Rh-rich spinels at one end, favored at higher temperatures and Fe-Cr spinels at the other end. For the first time Rh-containing spinel (up to 48 wt% Rh2 O3) has been identified as a liquidus phase. This Rh-rich spinel crystallization increases the liquidus temperature by about 150--200°C, even though Rh2O3 is present as low as 0.05wt%. The economic impact of this is huge. Using the transformation-time data measured at different temperatures for Zr, Th or U compounds, kinetic parameters were modeled using Avrami equation. Isokinetic crystallization is observed for baddeleyite and thorianite while non-isokinetic behavior is observed for zircon and parakeldyshite. Presence of a significant second phase or dramatic change in the morphology strongly influences the crystallization kinetics. The kinetic parameters depend on the liquidus phase, its volume fraction and temperature. The kinetic parameters obtained for crystallization of Zr, Th and U oxides or silicates can be used for designing HLW glass formulation as well as testing parameters.

Annamalai, Sezhian

153

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

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.

Rodriguez, Carmen P. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); ; Pierce, David A. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); ; Schweiger, Michael J. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); ; Kruger, Albert A. [USDOE Office of River Protection, Richland, WA (United States); Chun, Jaehun [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); ; Hrma, Pavel R. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States);

2013-12-03

154

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

NASA Technical Reports Server (NTRS)

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.

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

1983-01-01

155

Structure and thermal stability of iron-silicate nuclear waste glasses  

NASA Astrophysics Data System (ADS)

The paper discusses the relevance of a number of structural and microstructural characteristics for the evaluation of the physico-chemical stability of iron-silicate glasses developed for conditioning radioactive waste. Mössbauer spectroscopy is used to obtain information about the valency state and coordination of iron in the glass, whereas the study of devitrification kinetics and products allows one to conclude that for this type of material devitrification will not be a determining factor in the safety evaluation of any final disposal option.

De Batist, R.; Van Iseghem, P.; De Grave, E.; Stalios, A. D.

1989-12-01

156

Crystallization in simulated glasses from Hanford high-level nuclear waste composition range  

SciTech Connect

Glass crystallization was investigated as part of a property-composition relationship study of Hanford waste glasses. Non-radioactive glass samples were heated in a gradient furnace over a wide range of temperatures. The liquidus temperature was measured, and primary crystalline phases were determined using optical microscopy and Scanning Electron Microscopy with Energy Dispersive Spectrometry (SEM/EDS). Samples have also been heat treated according to a simulated canister centerline cooling curve. The crystalline phases in these samples have been identified by optical microscopy, SEM/EDS, and X-ray diffraction (XRD). Major components of the borosilicate glasses that were melted at approximately 1150{degrees}C were SiO{sub 2}, B{sub 2}O{sub 3}, Na{sub 2}O, Li{sub 2}O, CaO, MgO, Fe{sub 2}O{sub 3}, Al{sub 2}O{sub 3}, ZrO{sub 2}, and ``Others`` (sum of minor components). The major crystalline phases identified in this study were zircon, nepheline, calcium silicate, lithium silicate, and a range of solid solutions from clinopyroxenes, orthopyroxenes, olivines, and spiners.

Kim, Dong-Sang; Hrma, P.; Smith, D.E.; Schweiger, M.J.

1993-04-01

157

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,...

158

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

PubMed

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

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

2014-03-30

159

Vitrification of high chrome oxide nuclear waste in iron phosphate glasses  

Microsoft Academic Search

A simulated high level waste (HLW) containing 4 mass% chrome oxide, whose overall composition is representative of the high chrome oxide wastes at Hanford WA USA, was easily vitrified in a phosphate glass at temperatures ranging from 1150 °C, for waste loadings of 55 mass%, to 1250 °C for waste loadings of 75 mass%. Even at these high waste loadings,

Wenhai Huang; Delbert E. Day; Chandra S. Ray; Cheol-Woon Kim; Andrea Mogus-Milankovic

2004-01-01

160

Solid-state nuclear magnetic resonance investigations of surface layers in oxide glass systems  

NASA Astrophysics Data System (ADS)

A solid-state NMR study of leached surface layers of sodium-aluminosilicate glasses and characterization of multicomponent silicate glass surfaces is presented. The structure and composition of newly formed surface layers and mechanisms of their formation have been investigated to elucidate the surface and sub-surface chemistry. In addition, results of testing the applicability and sensitivity of solid-state NMR for characterization of commercial fiberglass surfaces are described. Cross-polarization from protons is used as a surface-selective NMR technique, since in these leached glasses all protons are present near the surface. CPMAS, 1H ? 29Si CPMAS, 1H ? 27Al CPMAS NMR and 1H/29Si/ 27Al cross-polarization transfer of populations via double-resonance (CP-TRAPDOR) experiments were employed to provide information about silicon and aluminum environments in the altered layers. Transformation of Al from four- to six-fold coordination is documented after leaching and alteration of the surface layers. The fraction of AlVI in the altered layer increases with the increase of duration of dissolution. The observed AlVI/(AlVI+AlIV) ratio correlates with the observed dissolution rate of the glass samples and the Al/Si ratio in the bulk. Such a correlation supports the hypothesis that AlVI forms on surfaces during dissolution. 29Si MAS, 27Al MAS and 27Al ? 29Si CPMAS NMR experiments additionally describe the bulk network structures in aluminosilicates. In certain instances, repolymerization of the silicon network via formation of additional Q4(0Al) silicon sites was observed in samples of leached glasses. NMR techniques were developed to identify surface degradation products, monitor chemical and structural changes on silicate glass surfaces that result from atmospheric exposure or from aqueous attack, and more importantly, allow a direct spectroscopic probe of surface silanol groups. Since NMR spectroscopy is too insensitive a technique to probe low surface area samples quantitatively, model and commercial silicate fiber surfaces are modified with a silylation agent ((3,3,3-trifluoropropyl) dimethylchlorosilane) containing --CF 3 end-groups. This allows the first 19F single-resonance NMR spectrum detection of a commercial fiberglass surface. In addition, a quantification analysis is presented, and the number of 19F atoms associated with this probe molecule attached to a fiber system are estimated.

Tsomaia, Natia

161

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

SciTech Connect

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.

Chun, Jaehun [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Pierce, David A. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Pokorny, Richard [Inst. of Chemical Technology, Prague (Czech Republic); Hrma, Pavel R. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Pohang Univ. of Science and Techology (Korea, Republic of)

2013-05-10

162

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

SciTech Connect

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.

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

163

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

NASA Astrophysics Data System (ADS)

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.

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

2009-11-01

164

Application of the NNWSI [Nevada Nuclear Waste Storage Investigations] unsaturated test method to actinide doped SRL [Savannah River Laboratory] 165 type glass  

SciTech Connect

The results of tests done using the Unsaturated Test Method are presented. These tests, done to determine the suitability of glass in a potential high-level waste repository as developed by the Nevada Nuclear Waste Storage Investigations Project, simulate conditions anticipated for the post-containment phase of the repository when only limited contact between the waste form and water is expected. The reaction of glass occurs via processes that are initiated due to glass/water vapor and glass/liquid water contact. Vapor interaction results in the initiation of an exchange process between water and the more mobile species (alkalis and boron) in the glass. The liquid reaction produces interactions similar to those seen in standard leaching tests, except due to the limited amount of water present and the presence of partially sensitized 304L stainless steel, the formation of reaction products greatly exceeds that found in MCC-1 type leach tests. The effect of sensitized stainless steel on the reaction is to enhance breakdown of the glass matrix thereby increasing the release of the transuranic elements from the glass. However, most of the Pu and Am released is entrained by either the metal components of the test or by the reaction phases, and is not released to solution. 16 refs., 20 figs., 17 tabs.

Bates, J.K.; Gerding, T.J.

1990-08-01

165

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

SciTech Connect

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.

Parnell, John (University of Aberdeen, Aberdeen, UK); Newsom, Horton E. (University of New Mexico, Albuquerque, NM); Blamey, Nigel J. F. (New Mexico Tech, Socorro, NM); Boslough, Mark Bruce Elrick

2010-10-01

166

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

167

Durability testing with West Valley borosilicate glass composition- Phase II. Progress in characterizing the WVDP Nuclear Waste Vitrification Process and Product by the Vitreous State Laboratory  

Microsoft Academic Search

This report presents the research performed by the Catholic University of America Vitreous State Laboratory (VSL) during FY 1987 in support of the West Valley Demonstration Project (WVDP) nuclear waste vitrification process. A principal objective of this work is the optimization of the glass composition be used for the vitrification of the liquid high-level waste generated at West Valley during

P. B. Macedo; S. M. Finger; A. A. Barkatt; I. L. Pegg; X. Feng; W. P. Freeborn

1988-01-01

168

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

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

169

Vitrification of high chrome oxide nuclear waste in iron phosphate glasses  

NASA Astrophysics Data System (ADS)

A simulated high level waste (HLW) containing 4 mass% chrome oxide, whose overall composition is representative of the high chrome oxide wastes at Hanford WA USA, was easily vitrified in a phosphate glass at temperatures ranging from 1150 °C, for waste loadings of 55 mass%, to 1250 °C for waste loadings of 75 mass%. Even at these high waste loadings, these wasteforms had an excellent chemical durability. The best chemical durability was achieved when the O/(Si + P) atomic ratio was between 3.5 and 3.8. These wasteforms were also resistant to crystallization although trace amounts of crystalline Cr 2O 3 were present in wasteforms containing more than 70 mass% HLW. It is concluded that up to 45 mass% of the total HLW at Hanford, especially that containing as high as 4.5 mass% chrome oxide, could be directly vitrified into an iron phosphate glass, that meets all of the current chemical durability requirements by simply adding 25-35 mass% P 2O 5 to the waste and melting the mixture at 1150-1250 °C for a few (<6) hours.

Huang, Wenhai; Day, Delbert E.; Ray, Chandra S.; Kim, Cheol-Woon; Mogus-Milankovic, Andrea

2004-04-01

170

Pr{sup 3+}-doped fluoro-oxide lithium glass as scintillator for nuclear fusion diagnostics  

SciTech Connect

Experimental results are presented on the neutron scintillating properties of a custom-designed Pr3+(praseodymium)-doped lithium (Li) glass. Luminescence was observed at 278 nm wavelength, originating from the 5d-4f transition. Time-resolved measurements yielded about 20 ns decay times for ultraviolet and x-ray excitation while much faster decay times of about 6 ns were observed for alpha particle and neutron excitation. Actual time-of-flight data in laser fusion experiments at the GEKKO XII facility of the Institute of Laser Engineering, Osaka University reveal that it can clearly discriminate fusion neutrons from the much stronger x-rays signals. This material can promise improved accuracy in future scattered neutron diagnostics.

Arikawa, Yasunobu; Yamanoi, Kohei; Nakazato, Tomoharu; Estacio, Elmer Surat; Shimizu, Toshihiko; Sarukura, Nobuhiko; Nakai, Mitsuo; Norimatsu, Takayoshi; Azechi, Hiroshi [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Murata, Takahiro [Department of Chemistry, School of Science, Tokai University, Kawayou, Minamiaso, Aso, Kumamoto 869-1404 (Japan); Fujino, Shigeru [Department of Materials Process Engineering, Graduate School of Engineering, Kyushu University, 744 Nishikyo Motooka, Fukuoka 819-0395 (Japan); Yoshida, Hideki [Ceramic Research Center of Nagasaki, Hiekoba, Hasami, Higashisonogi, Nagasaki 859-3726 (Japan); Kamada, Kei; Usuki, Yoshiyuki [Furukawa Co., Ltd., Kannondai, Tsukuba, Ibaraki 1-25-13 (Japan); Suyama, Toshihisa [Tokuyama Corporation Shibuya, 3-3-1, Shibuya, Tokyo 150-8383 (Japan); Yoshikawa, Akira [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoyou, Sendai, Miyagi 980-8577 (Japan); Sato, Nakahiro; Kan, Hirofumi [Central Research Laboratory, Hamamatsu Photonics K. K., 5000 Hiraguchi, Hamakitaku, Hamamatsu, Shizuoka 434-8601 (Japan)

2009-11-15

171

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

SciTech Connect

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.

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

2012-08-13

172

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...

173

The glass bead game: nuclear tourism at the Australian weapon test sites.  

PubMed

In mid-summer 1997, just as the United States National Cancer Institute was acknowledging that the nuclear bomb tests at the Nevada Test Site may ultimately cause up to 75,000 cases of thyroid cancer in people who were living in the USA in the 1950s and 1960s, the Australian authorities were mooting the possibility that the Maralinga test sites in South Australia should become a tourist attraction. Some Aboriginal tribal leaders welcomed this proposed use when the 20 million Pounds 'clean-up' being paid for by the United Kingdom government as some compensation for using the area for its weapons tests in the 1950s and 1960s is completed. This paper surveys the attempts to clean up the site of UK nuclear weapons tests in the 1950s, not least by attempting to vitrify vast tracts of desert. PMID:9838890

Roff, S R

1998-01-01

174

Thermochemical models for nuclear waste glass subsystems -- MgO-CaO and MgO-Al{sub 2}O{sub 3}  

SciTech Connect

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 allowed to exist below their melting point. The approach requires an initial assembly of binary and ternary oxide liquid solution data that sufficiently reproduce the equilibrium phase diagrams. Two binary oxide subsystems, MgO-CaO and MgO-Al{sub 2}O{sub 3}, have been modeled and results compared to published phase diagrams. Computed activities of the glass constituent species are plotted as a function of composition at 1,200 C.

Besmann, T.M.; Spear, K.E.; Beahm, E.C.

1999-07-01

175

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

SciTech Connect

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.

Jantzen, Carol

2005-10-10

176

Radioisotope generators for nuclear medicine based on Fajans adsorption on glass microspheres  

SciTech Connect

Several radioisotope generator systems exist in which the carrier-free daughter product would precipitate if present in macro amounts at pH levels at which the parent is soluble. Included among these are the {sup 68}Ge/{sup 68}Ga, {sup 90}Sr/{sup 90}Y, and {sup 47}Ca/{sup 47}Sc pairs. This paper reveals that in these systems, chemical separation can be achieved by Fajans adsorption of the radiocolloidal daughter products onto surfaces such as activated glass microspheres at an appropriate pH. This is followed by washing to remove the parent solution and desorption of the daughter crop by acid washes. Investigation of the Ge/Ga and Sr/Y systems demonstrated that this solid-phase extraction method is erratic, but can give daughter yields as high at 89% with separation factors up to {approximately} 10,000 form parent isotope. This method has the potential for producing daughter isotopes with a minimum of metal and organic impurities for labeling cells, receptor binding ligands, and antibodies for diagnostic and radiotherapeutic purposes.

Ehrhardt, G.J.; Symes, S.; Guimon, R.K.; Zinn, K.R. (Univ. of Missouri, Research Reactor, Columbia, MO (US))

1992-04-01

177

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

SciTech Connect

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?

Benjamin Michael Meyer

2003-05-31

178

Micro-fluidics and integrated optics glass sensor for in-line micro-probing of nuclear samples  

SciTech Connect

We study the miniaturization of Thermal Lens Spectrometry (TLS) towards Lab-on-chip integration in order to reduce the volume of fluid assays in nuclear process control. TLS is of great interest in this context since it combines the advantages of optical detection methods with an inherent suitability for small-scale samples. After validating the experimental principle in a classical thermal lens crossed-beam setup, we show the integration of a Young-interferometer with a microcapillary on a glass substrate, reducing the necessary sample size to 400 nl. The interferometer translates the photo-thermally induced refractive index change in the fluid to a phase shift of the fringe pattern, which can then be detected by a camera. Measurements of Co(II) in ethanol yield a detection limit of c = 5 x 10{sup -4} M for the crossed-beam setup and c = 6 x 10{sup -3} M for the integrated sensor. At an interaction length of 10 m, it detects a minimum absorbance of K = 1.2 x 10{sup -4} in a probed volume of 14 pl. (authors)

Schimpf, A.; Bucci, D.; Broquin, J.E. [Minatec, Inst Microelect Electromagnetisme et Photon IMEP L, F-38016 Grenoble 1, (France); Canto, F.; Magnaldo, A.; Couston, L. [Commissariat Energie Atom Marcoule, DEN-DRCP, F-30207 Bagnols Sur Ceze, (France)

2012-08-15

179

Micro-fluidics and integrated optics glass sensor for in-line micro-probing of nuclear samples  

SciTech Connect

We study the miniaturisation of Thermal Lens Spectrometry (TLS) towards Lab-on-chip integration in order to reduce the volume of fluid assays in nuclear process control. TLS is of great interest in this context since it combines the advantages of optical detection methods with an inherent suitability for small-scale samples. After validating the experimental principle in a classical thermal lens crossed-beam setup, we show the integration of a Young-interferometer with a microcapillary on a glass substrate, reducing the necessary sample size to 400 nl. The interferometer translates the photo-thermally induced refractive index change in the fluid to a phase shift of the fringe pattern, which can then be detected by a camera. Measurements of Co(II) in ethanol yield a detection limit of c = 5 x 10{sup -4} M for the crossed-beam setup and c = 6x10{sup -3} M for the integrated sensor. At an interaction length of 10 {mu}m, it detects a minimum absorbance of AU = 6 x 10{sup -5} in a probed volume of 10 pl. (authors)

Schimpf, A. [Institut de Microelectronique, Electromagnetisme et Photonique IMEP-LAHC Minatec, Batiment INP Grenoble, 3, parvis Louis Neel, BP 257, 38016 Cedex 1 (France); Canto, F. [Commissariat a l'Energie Atomique CEA de Marcoule, DEN - DRCP - SEAA - LAMM, BP17171, 30207 Bagnols sur Ceze Cedex (France); Bucci, D. [Institut de Microelectronique, Electromagnetisme et Photonique IMEP-LAHC Minatec, Batiment INP Grenoble, 3, parvis Louis Neel, BP 257, 38016 Cedex 1 (France); Magnaldo, A.; Couston, L. [Commissariat a l'Energie Atomique CEA de Marcoule, DEN - DRCP - SEAA - LAMM, BP17171, 30207 Bagnols sur Ceze Cedex (France); Broquin, J. E. [Institut de Microelectronique, Electromagnetisme et Photonique IMEP-LAHC Minatec, Batiment INP Grenoble, 3, parvis Louis Neel, BP 257, 38016 Cedex 1 (France)

2011-07-01

180

Local structures of mesoporous bioactive glasses and their surface alterations in vitro: inferences from solid-state nuclear magnetic resonance  

PubMed Central

We review the benefits of using 29Si and 1H magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy for probing the local structures of both bulk and surface portions of mesoporous bioactive glasses (MBGs) of the CaO–SiO2?(P2O5) system. These mesoporous materials exhibit an ordered pore arrangement, and are promising candidates for improved bone and tooth implants. We discuss experimental MAS NMR results from three MBGs displaying different Ca, Si and P contents: the 29Si NMR spectra were recorded either directly by employing radio-frequency pulses to 29Si, or by magnetization transfers from neighbouring protons using cross polarization, thereby providing quantitative information about the silicate speciation present in the pore wall and at the MBG surface, respectively. The surface modifications were monitored for the three MBGs during their immersion in a simulated body fluid (SBF) for intervals between 30 min and one week. The results were formulated as a reaction sequence describing the interconversions between the distinct silicate species. We generally observed a depletion of Ca2+ ions at the MBG surface, and a minor condensation of the silicate-surface network over one week of SBF soaking. PMID:22349247

Gunawidjaja, Philips N.; Mathew, Renny; Lo, Andy Y. H.; Izquierdo-Barba, Isabel; García, Ana; Arcos, Daniel; Mattias Edén, María Vallet-Regí

2012-01-01

181

Properties and behavior of the platinum group metals in the glass resulting from the vitrification of simulated nuclear fuel reprocessing waste  

Microsoft Academic Search

Two types of platinum group metal particles were found in borosilicate nuclear waste glasses: needle-shaped RuOâ particles and spherical PdRh{sub {ital x}}Te{sub {ital y}} alloys. They form a dense sediment of high electrical conductivity and relatively high viscosity at the bottom of the ceramic melting furnace. The sludge shows a non-Newtonian flow behavior. The viscosity and conductivity of the sludge

Ch. Krause; B. Luckscheiter

1991-01-01

182

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

SciTech Connect

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.

Kruger, A.A.

1995-07-01

183

Effect of different glasses in glass bonded zeolite  

SciTech Connect

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.

Lewis, M.A.; Ackerman, J.P. [Argonne National Lab., IL (United States); Verma, S. [Univ. of Illinois, Chicago, IL (United States)

1995-05-01

184

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

SciTech Connect

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.

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

2008-09-11

185

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

SciTech Connect

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.

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

2009-04-12

186

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

NASA Astrophysics Data System (ADS)

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.

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

2012-10-01

187

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

188

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

SciTech Connect

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.

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

2010-02-26

189

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

SciTech Connect

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.

Marra, J.; Billings, A.

2009-06-24

190

High level nuclear waste glass corrosion in synthetic clay pore solution and retention of actinides in secondary phases  

NASA Astrophysics Data System (ADS)

The corrosion of the simulated high level waste glass GP WAK1 in synthetic clay pore solution was studied in batch-type experiments at 323 and 363 K with special focus on the effect of high carbonate concentration in solution. The corrosion rate after 130 days was <10 -4 g m -2 d -1 - no significant effect of the carbonate was identified. During glass corrosion, crystalline secondary phases (powellite, barite, calcite, anhydrite and clay-like Mg(Ca,Fe)-silicates) were formed. To obtain a molecular level picture of radionuclide speciation within the alteration layer, spectroscopic methods have been applied including grazing incidence X-ray absorption spectroscopy (XAS) to study the structural changes in the coordination of uranyl upon alteration layer formation. The number of equatorial oxygen atoms increases from 4 in the bulk glass to 5 in the alteration layer. Furthermore, reduced coordination symmetry was found. Hectorite, a frequently observed secondary clay mineral within the glass alteration layer, was synthesized in the presence of trivalent f-elements (e.g. Eu) and structurally characterized using time-resolved laser fluorescence spectroscopy. Structural incorporation into the octahedral layer is indicated.

Bosbach, D.; Luckscheiter, B.; Brendebach, B.; Denecke, M. A.; Finck, N.

2009-03-01

191

Structural characterization and physical properties of P2O5-CaO-Na2O-TiO2 glasses by Fourier transform infrared, Raman and solid-state magic angle spinning nuclear magnetic resonance spectroscopies.  

PubMed

Phosphate-based glasses have been investigated for tissue engineering applications. This study details the properties and structural characterization of titanium ultra-phosphate glasses in the 55(P(2)O(5))-30(CaO)-(25-x)(Na(2)O)-x(TiO(2)) (0?x?5) system, which have been prepared via melt-quenching techniques. Structural characterization was achieved by a combination of X-ray diffraction (XRD), and solid-state nuclear magnetic resonance, Raman and Fourier transform infrared spectroscopies. Physical properties were also investigated using density, degradation and ion release studies; additionally, differential thermal analysis was used for thermal analysis of these glasses. The results show that with the addition of TiO(2) the density and glass transition temperature increased whereas the degradation and ion release properties are decreased. From XRD data, TiP(2)O(7) and CaP(2)O(6) were detected in 3 and 5 mol.% TiO(2)-containing glasses. Magic angle spinning nuclear magnetic resonance results confirmed that as TiO(2) is incorporated into the glass; the amount of Q(3) increases as the amount of Q(2) consequently decreases, indicating increasing polymerization of the phosphate network. Spectroscopy results also showed that the local structure of glasses changes with increasing TiO(2) content. As TiO(2) is incorporated into the glass, the phosphate connectivity increases, indicating that the addition of TiO(2) content correlates unequivocally with an increase in glass stability. PMID:21930253

Kiani, Azadeh; Hanna, John V; King, Scott P; Rees, Gregory J; Smith, Mark E; Roohpour, Nima; Salih, Vehid; Knowles, Jonathan C

2012-01-01

192

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

SciTech Connect

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.

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

1999-11-23

193

Thermodynamics and kinetics of crystallization of near-liquidus crystalline phases in defense nuclear waste glass melts  

Microsoft Academic Search

Vitrification has been identified as the primary mode of nuclear waste immobilization. Two important factors that affect the economic success of the vitrification program are waste loading and melter life. High-level nuclear waste (HLW) streams often contain significant amounts of Fe, Ni, Mn and Cr. Some of these waste streams contain significant amounts of Zr, Th & U. This often

Sezhian Annamalai

2007-01-01

194

Glass Works  

NSDL National Science Digital Library

This website is about glass and glass-making in Canada and it is presented by the Canadian Museum of Civilization. The site teaches visitors about natural glass, Canadian glass, practical glass, industrial glass, and inspirational glass. Before delving into the different ways glass is used in society, the website provides a thorough answer to the question "What is glass?" It is a mixture of sand, soda, and lime which is heated to extremely high temperatures, then cooled. Visitors will learn the benefits of glass, such as the fact that it is recyclable, inexpensive to produce from common materials, non-corrosive, and it also possesses the ability to be rolled, molded, blown, or cast. The "Making Glass" link shows visitors images of a glassworks furnace, an early 1900s automatic bottle-blowing machine, and a recipe for 2,000 pounds of amber-colored glass from the Dominion Glass Company. The "Practical Glass" link has photos of several objects such as a canning jar, goblet, flytrap, all of which are quite beautiful.

195

An alternative host matrix based on iron phosphate glasses for the vitrification of specialized nuclear waste forms. Annual progress report, September 15, 1996September 14, 1997  

Microsoft Academic Search

'Objectives of this project are to: (1) investigate the glass composition and processing conditions that yield optimum properties for iron phosphate glasses for vitrifying radioactive waste, (2) determine the atomic structure of iron phosphate glasses and the structure-property relationships, (3) determine how the physical and structural properties of iron phosphate glasses are affected by the addition of simulated high level

D. E. Day; C. S. Ray; K. Marasinghe

1997-01-01

196

Glass leaching performance  

SciTech Connect

Current understanding of the leaching performance of high-level nuclear waste (HLW) glass is summarized. The empirical model of waste glass leaching behavior developed shows that at high water flow rates the glass leach rate is kinetically limited to a maximum value. At intermediate water flow rates, leaching is limited by the solution concentration of silica and decreases with decreasing water flow rates. Release of soluble elements is controlled by silica dissolution because silica forms the binding network of the glass. At low water flow rates, mass loss rates reach values controlled by formation rates of alteration minerals, or by diffusion of dissolution products through essentially stagnant water. The parameters reviewed with respect to their quantifiable influence on leaching behavior include temperature, pH, leachant composition, glass composition, thermal history, and radiation. Of these, temperature is most important since the rate of mass loss approximately doubles with each 10/sup 0/C increase in dilute solutions. The pH has small effects within the 4 to 10 range. The chemical composition of the leachant is most important with regard to its influence on alteration product formation. Glass composition exhibits the largest effects at high flow rates where improved glasses leach from ten to thirty times slower than glass 76 to 68. The effects of the thermal history (devitrification) of the glass are not likely to be significant. Radiation effects are important primarily in that radiolysis can potentially drive pH values to less than 4. Radiation damage to the glass causes insignificant changes in leaching performance.

Chick, L.A.; Turcotte, R.P.

1983-05-01

197

Development of continuous liquid-fed laboratory-scale mini-melter for nuclear waste glass development  

SciTech Connect

A small, continuous liquid-fed mini-melter (LFMM) has been developed at Pacific Northwest Laboratory (PNL) to aid in waste glass feed slurry development. The LFMM offers several advantages over testing in large-scale melters. The LFMM requires little lead time in preparing for a test run, and the labor and material requirements are low. Real-time melting behavior of liquid feed slurries can be investigated, and feed rates can be estimated for larger-scale melters. The glass produced is representative of that produced by a larger-scale melter, as well as representative of the processing operation itself. Glass produced by the LFMM may subsequently be analyzed for metallic and other secondary phase formation. In contrast to larger-scale melters, the LFMM may be easily and inexpensively installed in a hot cell because of its relatively small size and simple configuration, enabling testing of radioactive feeds. A total of six LFMM experimental runs were performed. Feeds were obtained which corresponded to PNL melter runs performed in larger PNL developmental joule-heated research melters. These nonradioactive liquid-fed ceramic melters are known as the High-Bay Ceramic Melter (HBCM), the Experimental Ceramic Melter (ECM), and the Pilot-Scale Ceramic Melter (PSCM). Preliminary results obtained with the limited testing are promising. Feeds processed in the LFMM exhibited behavior closely resembling that observed in the large-scale melters. Feed rate correlations between the LFMM and ECM, HBCM, and PSCM were developed to estimate a range of expected feed rates for the large-scale melters from LFMM data. More developmental work with LFMM testing needs to be completed. Further testing will eliminate bias and establish the LFMM's true correlation to, and representation of, large-scale melters.

Reimus, M.A.H.; Marschman, S.C.; Graff, G.L.

1987-02-01

198

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)

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.

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

2008-12-01

199

Waste glass weathering  

SciTech Connect

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.

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

1993-12-31

200

Structural studies of NaPO3-MoO3 glasses by solid-state nuclear magnetic resonance and Raman spectroscopy.  

PubMed

Vitreous samples were prepared in the (100 - x)% NaPO(3)-x% MoO(3) (0 glass-forming system by a modified melt method that allowed good optical quality samples to be obtained. The structural evolution of the vitreous network was monitored as a function of composition by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), Raman scattering, and solid-state nuclear magnetic resonance (NMR) for (31)P, (23)Na, and (95)Mo nuclei. Addition of MoO(3) to the NaPO(3) glass melt leads to a pronounced increase in the glass transition temperatures up to x = 45, suggesting a significant increase in network connectivity. For this same composition range, vibrational spectra suggest that the Mo(6+) ions are bonded to some nonbridging oxygen atoms (Mo-O- or Mo=O bonded species). Mo-O-Mo bond formation occurs only at MoO(3) contents exceeding x = 45. (31)P magic-angle spinning (MAS) NMR spectra, supported by two-dimensional J-resolved spectroscopy, allow a clear distinction between species having two, one, and zero P-O-P linkages. These sites are denoted as Q(2)(2Mo), Q(2)(1Mo), and Q(2)(0Mo), respectively. For x < 0.45, the populations of these sites can be described along the lines of a binary model, according to which each unit of MoO(3) converts two Q(2)(nMo) sites into two Q(2)((n+1)Mo) sites (n = 0, 1). This structural model is consistent with the presence of tetrahedral Mo(=O)2(O(1/2))2 environments. Indeed, (95)Mo NMR data suggest that the majority of the molybdenum species are four-coordinated. However, the presence of additional six-coordinate molybdenum in the MAS NMR spectra indicates that the structure of these glasses may be more complicated and may additionally involve sharing of network modifier oxide between the network formers phosphorus and molybdenum. This latter hypothesis is further supported by (23)Na{(31)P} rotational echo double resonance (REDOR) data, which clearly reveal that the magnetic dipole-dipole interactions between (31)P and (23)Na are increasingly diminished with increasing molybdenum content. The partial transfer of modifier from the phosphate to the molybdate network former implies a partial repolymerization of the phosphate species, resulting in the formation of Q(3)(nMo) species and accounting for the observed increase in the glass transition temperature with increasing MoO(3) content that is observed in the composition range 0 Glasses with MoO(3) contents beyond x = 45 show decreased thermal and crystallization stability. Their structure is characterized by isolated phosphate species [most likely of the P(OMo)4 type] and molybdenum oxide clusters with a large extent of Mo-O-Mo connectivity. PMID:17683136

Santagneli, Silvia H; de Araujo, Carla C; Strojek, Wenzel; Eckert, Hellmut; Poirier, Gaël; Ribeiro, Sidney J L; Messaddeq, Younes

2007-08-30

201

Glass corrosion in natural environments  

NASA Technical Reports Server (NTRS)

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.

Thorpe, Arthur N.; Barkatt, Aaron

1992-01-01

202

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

203

Effect of composition and temperature on viscosity and electrical conductivity of borosilicate glasses for Hanford nuclear waste immobilization  

SciTech Connect

Viscosity and electrical conductivity of 79 simulated borosilicate glasses in the expected range of compositions to be produced in the Hanford Waste Vitrification Plant were measured within the temperature span from 950 to 1250[degree]C. The nine major oxide components were SiO[sub 2], B[sub 2]O[sub 3], Li[sub 2]O, Na[sub 2]O, CaO, MgO, Fe[sub 2]O[sub 3], Al[sub 2]O[sub 3], and ZrO[sub 2]. The test compositions were generated statistically. The data were fitted by Fulcher and Arrhenius equations with temperature coefficients being multilinear functions of the mass fractions of the oxide components. Mixture models were also developed for the natural logarithm of viscosity and that of electrical conductivity at 1150[degree]C. Least squares regression was used to obtain component coefficients for all the models.

Hrma, P.; Piepel, G.F.; Smith, D.E.; Redgate, P.E.; Schweiger, M.J.

1993-04-01

204

Electron spin resonance study of Fe3+ and Mn2+ ions in 17-year-old nuclear-waste-glass simulants containing PuO2 with different degrees of 238Pu substitution  

Microsoft Academic Search

Three samples of a model nuclear waste glass, DRG-P1, P2, and P3, were prepared at PNNL in 1982 with identical chemical compositions but were respectively batched with 0.0, 0.1, and 0.9 wt% of 238PuO2 (half life 87.8 years) partially replacing the 1.0 wt% 239PuO2 present in DRG-P1. In 1999, samples of these glasses were sent to the Naval Research Laboratory

David L. Griscom; William J. Weber

2011-01-01

205

Glass Artworks  

NASA Technical Reports Server (NTRS)

Several NASA technologies have played part in growth and cost containment of studio glass art, among them a foam type insulation developed to meet a need for lightweight material that would reduce flame spread in aircraft fire. Foam comes in several forms and is widely used by glass artists, chiefly as an insulator for the various types of ovens used in glass working. Another Spinoff is alumina crucibles to contain molten glass. Before alumina crucibles were used, glass tanks were made of firebrick which tended to erode under high temperatures and cause impurities; this not only improved quality but made the process more cost effective. One more NASA technology that found its way into glass art working is a material known as graphite board, a special form of graphite originally developed for rocket motor applications. This graphite is used to exact compound angles and creates molds for poured glass artworks of dramatic design.

1988-01-01

206

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

SciTech Connect

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.

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

1999-06-22

207

glass ceramic  

NASA Astrophysics Data System (ADS)

Glass sample with a composition of Li1.3Nb0.3Fe1.7(PO4)3, prepared by a conventional melt-quenching method, was heat treated to obtain glass ceramics of NASICON type. Glass transition ( T g) and crystallization ( T c) temperatures of as-quenched glass sample were determined by differential thermal analysis (DTA). X-ray diffraction (XRD) patterns also confirmed the formation of glass sample. After heat treatment above T c, precipitation of crystalline particles with NASICON-type structure was confirmed by XRD. Valency and local structure of Fe atoms were investigated by Mössbauer spectroscopy at room temperature. DC-conductivity and impedance measurements of the glass ceramics proved the increased electrical conduction caused by heat treatment.

Hassaan, M. Y.; Salem, S. M.; Moustafa, M. G.; Kubuki, S.; Matsuda, K.; Nishida, T.

2014-04-01

208

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

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

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

2013-02-21

209

Rainbow Glasses  

NSDL National Science Digital Library

In this activity, learners explore light, color and rainbows by making their own rainbow glasses. Learners glue "rainbow optics paper" onto the glasses cutout, add decorations and attach pipe cleaner earpieces. Learners name the different colors they observe and notice that the colors always appear in the same order. This activity guide includes open-ended questions to help learners explore these topics further.

OMSI

2004-01-01

210

Glass-An Environmental Protector  

SciTech Connect

From asbestos abatement to lead paint removal to nuclear waste stabilization and even to heavy metal removal using microorganisms, glass has great potential as a solution to many environmental problems. The ability to accommodate an array of chemical elements within the glass structure has facilitated the use of glass as a medium for the stabilization of numerous hazardous substances. The resulting glasses have proven to be durable enough for direct land disposal. In many cases, the stabilized forms have been deemed suitable for re-use in other applications. As recycling and hazardous material treatment become even more important in the global materials cycle, it is a certainty that glass will assume a prominent role.

MARRA, JAMES

2004-11-01

211

MIIT: International in-situ testing of nuclear-waste glasses: Performance of SRS simulated waste glass after five years of burial at the Waste Isolation Pilot Plant (WIPP)  

SciTech Connect

In July of 1986, the first in-situ test involving burial of simulated high-level waste (HLW) forms conducted in the United States was started. This program, called the Materials Interface Interactions Test or MIIT, comprises the largest, most cooperative field-testing venture in the international waste management community. In July of 1991, the experimental portion of the 5-year MIIT study was completed on schedule. During this time interval, many in-situ measurements were performed, thousands of brine analyses conducted, and hundreds of waste glass and package components exhumed and evaluated after 6 mo., 1 yr., 2 yr. and 5 yr. burial periods. Although analyses are still in progress, the performance of SRS waste glass based on all data currently available has been seen to be excellent thus far. Initial analyses and assessment of Savannah River (SR) waste glass after burial in WIPP at 90{degrees}C for 5 years are presented in this document.

Wicks, G.G. [Westinghouse Savannah River Co., Aiken, SC (United States); Lodding, A.R. [Chalmers Univ. of Technology, Goeteborg (Sweden); Macedo, P.B. [Catholic Univ. of America, Washington, DC (United States); Clark, D.E. [Florida Univ., Gainesville, FL (United States)

1991-12-31

212

MIIT: International in-situ testing of nuclear-waste glasses: Performance of SRS simulated waste glass after five years of burial at the Waste Isolation Pilot Plant (WIPP)  

SciTech Connect

In July of 1986, the first in-situ test involving burial of simulated high-level waste (HLW) forms conducted in the United States was started. This program, called the Materials Interface Interactions Test or MIIT, comprises the largest, most cooperative field-testing venture in the international waste management community. In July of 1991, the experimental portion of the 5-year MIIT study was completed on schedule. During this time interval, many in-situ measurements were performed, thousands of brine analyses conducted, and hundreds of waste glass and package components exhumed and evaluated after 6 mo., 1 yr., 2 yr. and 5 yr. burial periods. Although analyses are still in progress, the performance of SRS waste glass based on all data currently available has been seen to be excellent thus far. Initial analyses and assessment of Savannah River (SR) waste glass after burial in WIPP at 90{degrees}C for 5 years are presented in this document.

Wicks, G.G. (Westinghouse Savannah River Co., Aiken, SC (United States)); Lodding, A.R. (Chalmers Univ. of Technology, Goeteborg (Sweden)); Macedo, P.B. (Catholic Univ. of America, Washington, DC (United States)); Clark, D.E. (Florida Univ., Gainesville, FL (United States))

1991-01-01

213

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)

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.

Hassan, Razi A.

1991-01-01

214

Edible Glass  

NSDL National Science Digital Library

In this activity, learners discover the principles of edible glass by making a supersaturated sugar solution. The goal of this activity is to provide an interesting experiment which learners of many different levels can perform. The write-up for this activity provides explanatory information that presents the experiment from several different perspectives. This activity includes an introduction to common sugars, as well as some discussion of temperature and thermometry, basic thermodynamics, and the experimental procedure to make the candy glass.

Josh Pomeroy

2012-01-01

215

Nuclear  

NSDL National Science Digital Library

What part does nuclear energy play in satisfying energy demands? This informational piece, part of a series about the future of energy, introduces students to the uranium atom as an energy source. Here students read about the history of nuclear energy, how energy is derived from uranium, and benefits of nuclear energy. Information is also provided about limitations, particularly disposal problems and radioactivity, and geographical considerations of nuclear power in the United States. Thought-provoking questions afford students chances to reflect on what they've read about the uses of nuclear power. Articles and information on new nuclear plant design and nuclear accidents are available from a sidebar. Five energy-related PBS NewsHour links are provided. A web link to the U.S. Nuclear Regulatory Commission is included. Copyright 2005 Eisenhower National Clearinghouse

Iowa Public Television. Explore More Project

2004-01-01

216

DURABLE GLASS FOR THOUSANDS OF YEARS  

SciTech Connect

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.

Jantzen, C.

2009-12-04

217

Durability of Silicate Glasses: An Historical Approach  

SciTech Connect

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.

Farges, Francois; /Museum Natl. Hist. Natur. /Stanford U., Geo. Environ. Sci.; Etcheverry, Marie-Pierre; /Marne la Vallee U.; Haddi, Amine; /Marne la Valle U.; Trocellier,; /Saclay; Curti, Enzo; /PSI, Villigen; Brown, Gordon E., Jr.; /SLAC, SSRL

2007-01-02

218

Vitrification chemistry and nuclear waste  

Microsoft Academic Search

The vitrification of nuclear waste offers unique challenges to the glass technologist. The waste contains 50 or 60 elements, and often varies widely in composition. Most of these elements are seldom encountered in processing commercial glasses. The melter to vitrify the waste must be able to tolerate these variations in composition, while producing a durable glass. This glass must be

Plodinec

1985-01-01

219

Iron phosphate glass containing simulated fast reactor waste: Characterization and comparison with pristine iron phosphate glass  

NASA Astrophysics Data System (ADS)

Detailed characterization was carried out on an iron phosphate glass waste form containing 20 wt.% of a simulated nuclear waste. High temperature viscosity measurement was carried out by the rotating spindle method. The Fe3+/Fe ratio and structure of this waste loaded iron phosphate glass was investigated using Mössbauer and Raman spectroscopy respectively. Specific heat measurement was carried out in the temperature range of 300-700 K using differential scanning calorimeter. Isoconversional kinetic analysis was employed to understand the crystallization behavior of the waste loaded iron phosphate glass. The glass forming ability and glass stability of the waste loaded glass were also evaluated. All the measured properties of the waste loaded glass were compared with the characteristics of pristine iron phosphate glass.

Joseph, Kitheri; Asuvathraman, R.; Venkata Krishnan, R.; Ravindran, T. R.; Govindaraj, R.; Govindan Kutty, K. V.; Vasudeva Rao, P. R.

2014-09-01

220

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

SciTech Connect

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.

Langowski, M.H.

1996-02-01

221

Prediction of glass durability as a function of environmental conditions  

SciTech Connect

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.

Jantzen, C.M.

1988-01-01

222

Glass Ceramic Formulation Data Package  

SciTech Connect

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.

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

2012-06-17

223

Glass Furnace Project: October 1981March 1982  

Microsoft Academic Search

The purpose of the Glass Furnace Project is to evaluate the use of a joule-heated glass furnace, fitted with a Mound-developed offgas system, to reduce the volume of contaminated waste typical of that from nuclear power plants. As part of the project, several different waste types, including dry solid waste, ion exchange resin, and sludge, will be burned in the

K. M. Armstrong; L. M. Klingler

1982-01-01

224

Glass Furnace Project: October 1980March 1981  

Microsoft Academic Search

Purpose of the Glass Furnace Project is to evaluate the use of the Penberthy Pyro-Converter, fitted with a Mound-developed offgas system, to reduce the volume of contaminated waste typical of that from nuclear power plants. Several different waste types, including dry solid waste, ion exchange resin, and sludge, will be burned in the glass furnace unit. Combustion characteristics and radionuclide

B. M. Alexander; L. M. Klingler

1981-01-01

225

Engineering Glass Passivation Layers Model Results  

Microsoft Academic Search

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

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

2011-01-01

226

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

SciTech Connect

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.

Jantzen, C.M.

1988-01-01

227

Pinhole Glasses  

NASA Astrophysics Data System (ADS)

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.

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

2008-01-01

228

Na, Mg, Ni and Cs distribution and speciation after long-term alteration of a simulated nuclear waste glass: A micro-XAS/XRF/XRD and wet chemical study  

NASA Astrophysics Data System (ADS)

Microscopic distribution and speciation of Na, Mg, Ni and Cs in a simulated (inactive) nuclear waste glass were studied using micro X-ray fluorescence (?-XRF) and micro X-ray absorption spectroscopy (?-XAS), after aqueous leaching during 12 years at 90 °C. Na and Mg are major constituents of the glass that can be used to determine the progress of the glass corrosion process and the nature of secondary alteration phases. Ni and Cs represent dose determining long-lived radionuclides ( 59Ni, 135Cs) in vitrified nuclear waste. The Na-Mg ?-XRF maps revealed that the core regions of the glass fragments are apparently unaltered and compositionally homogeneous, whereas rims and interstitial spaces are enriched with Mg-rich smectite formed during the leaching process. The micro X-ray absorption near edge structure (?-XANES) spectra collected at the Mg K-edge in the altered zones show three sharp resonances typical for crystalline Mg-silicates. These resonances are distinctive of Mg occupying undistorted octahedral positions. In contrast, the ?-XANES spectra collected in the core zones of the glass fragments lack this resonance pattern and are identical to the spectra measured on the pristine (unleached) MW glass. Micro extended X-ray absorption fine structure (?-EXAFS) and ?-XANES analyses at the Ni K-edge revealed three distinct Ni(II) species: (a) Ni uniformly distributed in the glass matrix, (b) micro-inclusions with high Ni concentrations and (c) Ni associated to the Mg-clay. The comparison with reference spectra of unleached MW and other Ni-bearing silicate glasses indicated that species (a) represents the original coordinative environment of Ni in the glass. The ?-EXAFS analyses revealed that species (b) is structural Ni in trevorite (NiFe 2O 4), which probably formed through unmixing processes during the cooling of the glass melt. The ?-EXAFS of species (c) could be successfully modeled assuming specific adsorption or incorporation of Ni into the lattice of trioctahedral Mg-clay minerals. Alternative models assuming other elements (Ni, Al, Fe) in addition to Mg in the second shell could not be fitted successfully. Aqueous concentration data were used to calculate the speciation of the leaching solutions. Saturation index (SI) calculations indicate undersaturation with respect to NiCO 3 and NiSO 4·7H 2O, but oversaturation with respect to ?-Ni(OH) 2. The latter result is probably due to the omission of Ni borate and Ni silicate complexes in the speciation calculations, for which formation constants are not available. With the help of estimation techniques, we could infer that such complexes would dominate the Ni speciation and consequently reduce the SI below the saturation of ?-Ni(OH) 2. The ?-XRF maps show that Cs is uniformly distributed in the MW glass, since no region with high Cs concentration could be detected. The Cs L III-edge ?-XAS spectra were all very similar independently of the degree of alteration, indicating similar coordination environments of Cs in the core regions of the glass as well as in the secondary clays. These spectra largely differ from that measured for pollucite (a potential secondary Cs-phase in altered glasses) implying that the coordination environments of Cs in the MW glass and in pollucite are fundamentally different. The present study shows that ?-XRF and ?-XAS are essential tools in determining the fate and the retention mechanisms of radionuclides released from nuclear waste during aqueous alteration. Our spectroscopic analyses allowed us to exclude formation of specific Ni and Cs secondary solids (e.g. nepouite, ?-Ni(OH) 2, pollucite) during the aqueous alteration. Ni and Cs are instead distributed as trace elements in the alteration phases formed by major elements during the leaching process. Our results imply that solid solution and/or adsorption equilibria, rather than pure phase solubility equilibria, are the adequate chemical models to determine Ni and Cs aqueous concentrations in performance assessments for radioactive waste repositories.

Curti, Enzo; Dähn, Rainer; Farges, François; Vespa, Marika

2009-04-01

229

Hot isostatically-pressed aluminosilicate glass-ceramic with natural crystalline analogues for immobilizing the calcined high-level nuclear waste at the Idaho Chemical Processing Plant  

SciTech Connect

The additives Si, Al, MgO, P{sub 2}O{sub 5} were mechanically blended with fluorinelsodium calcine in varying proportions. The batches were vacuum sealed in stainless steel canisters and hot isostatically pressed at 20,000 PSI and 1000 C for 4 hours. The resulting suite of glass-ceramic waste forms parallels the natural rocks in microstructural and compositional heterogeneity. Several crystalline phases ar analogous in composition and structure to naturally occurring minerals. Additional crystalline phases are zirconia and Ca-Mg borate. The glasses are enriched in silica and alumina. Approximately 7% calcine elements occur dissolved in this glass and the total glass content in the waste forms averages 20 wt%. The remainder of the calcine elements are partitioned into crystalline phases at 75 wt% calcine waste loading. The waste forms were tested for chemical durability in accordance with the MCC1-test procedure. The leach rates are a function of the relative proportions of additives and calcine, which in turn influence the composition and abundances of the glass and crystalline phases. The DOE leach rate criterion of less than 1 g/m{sup 2}-day is met by all the elements B, Cs and Na are increased by lowering the melt viscosity. This is related to increased crystallization or devitrification with increases in MgO addition. This exploratory work has shown that the increases in waste loading occur by preferred partitioning of the calcine components among crystalline and glass phases. The determination of optimum processing parameters in the form of additive concentration levels, homogeneous blending among the components, and pressure-temperature stabilities of phases must be continued to eliminate undesirable effects of chemical composition, microstructure and glass devitrification.

Raman, S.

1993-12-01

230

Pinhole Glasses  

ERIC Educational Resources Information Center

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…

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

2008-01-01

231

Temperature effects on waste glass performance  

SciTech Connect

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.

Mazer, J.J.

1991-02-01

232

Structure of rhenium-containing sodium borosilicate glass  

SciTech Connect

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.

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

2013-03-01

233

Glass viscosity calculation based on a global statistical modelling approach  

SciTech Connect

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.

Fluegel, Alex

2007-02-01

234

Vitrification of nuclear waste in a transferred arc plasma melter  

NASA Astrophysics Data System (ADS)

Borosilica glass, high silica glass, and a variety of sphene glass-ceramic synrock have been melted in a batch transferred arc plasma melter. Simulated nuclear waste was also melted into borosilicate glass and high silica glass and sphene glass-ceramic. The loss of total glass weight and the losses of Na, Cs, U and Nd elements were examined as a function of operating conditions. Cs losses were high for all conditions tested, ranging from 50 to 90%.

Munz, R. J.; Chen, G. Q.

1989-02-01

235

IMPACT STRENGTH OF GLASS AND GLASS CERAMIC  

SciTech Connect

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.

Bless, S.; Tolman, J. [Institute for Advanced Technology, University of Texas at Austin, Austin, TX 78759 (United States)

2009-12-28

236

Gaseous Sulfate Solubility in Glass: Experimental Method  

SciTech Connect

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.

Bliss, Mary

2013-11-30

237

Alteration of glasses by micro-organisms  

NASA Astrophysics Data System (ADS)

Micro-organisms are suspected to play a basic part in materials alteration. Obviously, they will be present in nuclear waste repositories, either introduced by technological activity or laid by fluids circulation. Their metabolism may induce chemical modifications to the surrounding media and then affect the durability of storage materials. Biodegradation of glasses is studied in the Pierre Süe Laboratory. In the frame of a collaboration with microbiologists interested in stained glasses alteration, leaching experiments with various species of bacteria and fungi are carried out. Ion beam analysis techniques are performed to quantify surface modification of glasses and elemental incorporation in micro-organisms. Analyses of the solutions will lead to a complete assessment of elemental exchanges between glass sample, culture media and micro-organisms. In this paper, preliminary results on characterisation of glasses and micro-organisms and the first results of leaching experiments are presented.

Gallien, Jean-Paul; Gouget, Barbara; Carrot, Francine; Orial, Geneviève; Brunet, Anne

2001-07-01

238

Electron Spin Resonance Study of Fe3+ and Mn2+ Ions in 17-Year-Old Nuclear-Waste-Glass Simulants Containing PuO2 with Different Degrees of 238Pu Substitution  

SciTech Connect

Three samples of a model nuclear waste glass, DRG-P1, P2, and P3, were prepared at PNNL in 1982 with identical chemical compositions but were respectively batched with 0.0, 0.1, and 0.9 wt% of 238PuO2 (half life 87.8 years) partially replacing the 1.0 wt% 239PuO2 present in DRG-P1. In 1999, samples of these glasses were sent to the Naval Research Laboratory for electron spin resonance (ESR) measurements. No radiation-induced point defects were observed. Profound alpha decay-induced changes in the ESR spectra of the batched iron-group ions were found. The spectra recorded for DRG-P1 were shown by absolute spin counts to have ESR intensities equivalent to ~85% of the sum of the batched 8.28 mole% Fe3+ and 2.79 mole% Mn2+, assuming all of those ions to behave as paramagnetic S=5/2 states at room temperature. Separate experiments and calculations ruled out the possibility of precipitated magnetite-like precipitates comprising even so much as 0.01% of the total iron. A relatively weak ESR spectral feature observed at g=4.3 is the known signature of dilute Fe3+ in glasses. However, the strongest ESR signal was found to be characterized by a first-derivative zero crossing at g=2.06 and a peak-to-peak derivative linewidth of ~150 mT, which is virtually invariant in shape with both measurement temperature and alpha-decay dose. It was discovered that these broad line shapes could be accurately simulated as weighted sums of Lorentzian shape functions of differing widths but having the same g value. The absence of any measurable anisotropy in the broad line, coupled with the temperature invariance of its width, imply the existence of extremely strong exchange interactions within clusters of Fe3+, Fe2+, Mn2+, and Ni2+ ions characterized by extremely short-range magnetic order. The result is a speromagnetic system rather than exhibiting a distinct Néel temperature. The most evident ESR effect of 17 years of 238Pu decay is the (irreversible) lowering of the intensity of the "broad line" in rough proportion to the amount of 238Pu in the sample, with concomitant increases in the amplitude of the g=4.3 feature. It was additionally observed that cooling these glasses to successively lower temperatures gives rise to reversible lowering of the broad-line intensity and increasing of the strength of the g=4.3 feature when compared with theoretical expectation for non-interacting paramagnets. The truly remarkable observation that the broad lines could be simulated as weighted sums of pure Lorentzian functions of differing widths fortuitously opened the way for high precision measurements of the ESR intensities of experimental spectra that are far broader than the magnetic field range of the available laboratory electromagnets. The areas under the simulated absorption curves fitted to the experimental spectra in the manner described provided an empirical measure of the degrees to which the present model nuclear waste glasses had been affected by alpha-decay self irradiation. Specifically, the broad-line ESR integrated-intensity data as a function of 238Pu alphadecay dose (proportional to the 238Pu doping level in these fixed-time experiments) proved to be accurately fitted by a simple saturating exponential function asymptotic to zero for infinite-time self irradiation. This result promises a precise means of extrapolating thousands of years into the future the process of "super-vitrification" that results from the creation and rapid quenching of thermal spikes due to alpha decay in glasses immobilizing 239Pu and other actinide elements. In addition, because the ESR spectra of several very different candidate high-level nuclear waste (HLW) glass compositions containing even higher amounts of Fe2O3 are also shown here to be decomposable into sums of pure Lorentzians, the analytical method we describe should be applicable to these and many other HLW glasses containing both iron-group oxides and radionuclides.

Griscom, David L.; Weber, William J.

2011-03-01

239

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

240

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

PubMed

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

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

2015-01-01

241

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

PubMed Central

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

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

2015-01-01

242

NEWS & VIEWS Glass dynamics  

E-print Network

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

Weeks, Eric R.

243

Glass-silicon column  

DOEpatents

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.

Yu, Conrad M.

2003-12-30

244

DEVELOPMENT OF GLASS MATRICES FOR HLW RADIOACTIVE WASTES  

SciTech Connect

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.

Jantzen, C.

2010-03-18

245

Surface layer effects on waste glass corrosion  

SciTech Connect

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.

Feng, X.

1993-12-31

246

Hyperpolarized cesium ions doped in a glass material.  

PubMed

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 (9.4T). 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. PMID:25462952

Ishikawa, Kiyoshi

2014-10-17

247

Hyperpolarized cesium ions doped in a glass material  

NASA Astrophysics Data System (ADS)

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.

Ishikawa, Kiyoshi

2014-12-01

248

Picture Wall (Glass Structures)  

NASA Technical Reports Server (NTRS)

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.

1978-01-01

249

Reaction cured glass and glass coatings  

NASA Technical Reports Server (NTRS)

The invention relates to reaction cured glass and glass coatings prepared by reacting a compound selected from the group consisting of silicon tetraboride, silicon hexaboride, other boron silicides, boron and mixtures with a reactive glass frit composed of a porous high silica borosilicate glass and boron oxide. The glassy composites of the present invention are useful as coatings on low density fibrous porous silica insulations used as heat shields and for articles such as reaction vessels that are subjected to high temperatures with rapid heating and cooling and that require resistance to temperature and repeated thermal shock at temperatures up to about 1482C (2700PF).

Goldstein, H. E.; Leiser, D. B.; Katvala, V. W. (inventors)

1978-01-01

250

Glasses in the D'Orbigny angrite  

NASA Astrophysics Data System (ADS)

The angrites are a small and heterogeneous group of achondritic meteorites with highly unusual chemical and mineralogical features. The abundant presence of glasses in D'Orbigny makes this rock a unique member of the angrite group. Glasses fill open spaces, form pockets, and occur as inclusions in olivines. Their physical settings exclude an incorporation from an external source. Major and trace element (rare earth elements [REE], Li, B, Be, transition elements, N and C) contents of these glasses and host olivines were measured combining laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), secondary-ion mass spectrometry (SIMS), Nuclear Reaction Analysis (NRA), and EMP techniques. Based on the major element composition, glasses filling voids could represent either a melt formed by melting an angritic rock or a melt from which angrites could have crystallized. Trace element contents of these glasses strongly indicate a direct link to the D'Orbigny bulk meteorite. They are incompatible with the formation of the glasses by partial melting of a chondritic source rock or by shock melting. The refractory elements (e.g., Al, Ti, Ca) have about 10 × CI abundances with CaO/TiO 2 and FeO/MnO ratios being approximately chondritic. Trace element abundances in the glasses appear to be governed by volatility and suggest that the refractory elements in the source had chondritic relative abundances. Although the glasses (and the whole rock) lack volatile elements such as Na and K, they are rich in some moderately volatile elements such as B, V, Mn, Fe (all with close to CI abundances), and Li (about 3-5 × CI). These elements likely were added to the glass in a sub-solidus metasomatic elemental exchange event. We have identified a novel mechanism for alteration of glass and rock compositions based on an exchange of Al and Sc for Fe and other moderately volatile elements in addition to the well-known metasomatic exchange reactions (e.g., Ca-Na and Mg-Fe). Because glass inclusions in olivine were partly shielded from the metasomatic events by the host crystal, their chemical composition is believed to be closer to the original composition than that of any other glasses. The relative trace element abundances in glasses of glass inclusions in olivine and glass pockets are also unfractionated and at the 10 to 20 × CI level. These glasses are chemically similar to the common void-filling glasses but show a much wider compositional variation. Inclusion glasses demonstrate that at least olivine grew with the help of a liquid. In analogy to olivines in carbonaceous chondrites, initial formation could also have been a vapor-liquid-solid condensation process. At that time, the glass had a purely refractory composition. This composition, however, was severely altered by the metasomatic addition of large amounts of FeO and other moderately volatile elements. The presence of volatile elements such as carbon and nitrogen in glasses of glass inclusions is another feature that appears to give these glasses a link with those hosted by olivines of carbonaceous chondrites. All these features point to an origin from a vapor with relative abundances of condensable elements similar to those in the solar nebula.

Varela, Maria Eugenia; Kurat, Gero; Zinner, Ernst; Métrich, Nicole; Brandstätter, Franz; Ntaflos, Theodoros; Sylvester, Paul

2003-12-01

251

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

252

Thermochemical study of rare earth and nitrogen incorporation in glasses  

Microsoft Academic Search

Rare earth containing aluminosilicate, borosilicate, aluminate and nitrogen containing aluminosilicate glasses are technically important materials. They have extraordinary physical and chemical properties such as high glass transition temperature, very low electrical conductivity, and excellent chemical stability. These unique properties lead to applications as coatings on metals and ceramics, optical fibers, semiconductors, and nuclear waste containment materials. In addition, such systems

Yahong Zhang

2003-01-01

253

Oxynitride glass fibers  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

254

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...

255

Accelerated glass reaction under PCT conditions  

SciTech Connect

Static leach tests similar to PCT (Product Consistency Test) were performed for up to 2 years to assess long-term reaction behavior of high-level nuclear waste glasses similar to those at Defense Waste Processing Facility. These tests show the reaction rate to decrease with the reaction time from an initially high rate to a low rate, but then to accelerate to a higher rate after reaction times of about 1 year, depending on glass surface area/leachant volume ratio used. Solution concentrations of soluble glass components increase as the reaction is accelerated, while release of other glass components into solution is controlled by secondary phases. Net result is that transformation of glass to stable phases is accelerated while the solution becomes enriched in soluble components not effectively contained in secondary phases. Rate becomes linear in time after the acceleration and may be similar to the initial forward rate. A current model of glass reaction predicts that the glass reaction will be accelerated upon the formation of secondary phases which lower the silicic acid solution concentration. These tests show total Si concentration to increase upon reaction acceleration, however, which may be due to the slightly higher pH attained with the acceleration. The sudden change in the reaction rate is likely due to secondary phase formation. 17 refs, 2 tabs, 3 figs.

Ebert, W.L.; Bates, J.K.; Buck, E.C.; Bradley, C.R.

1992-01-01

256

Accelerated glass reaction under PCT conditions  

SciTech Connect

Static leach tests similar to PCT (Product Consistency Test) were performed for up to 2 years to assess long-term reaction behavior of high-level nuclear waste glasses similar to those at Defense Waste Processing Facility. These tests show the reaction rate to decrease with the reaction time from an initially high rate to a low rate, but then to accelerate to a higher rate after reaction times of about 1 year, depending on glass surface area/leachant volume ratio used. Solution concentrations of soluble glass components increase as the reaction is accelerated, while release of other glass components into solution is controlled by secondary phases. Net result is that transformation of glass to stable phases is accelerated while the solution becomes enriched in soluble components not effectively contained in secondary phases. Rate becomes linear in time after the acceleration and may be similar to the initial forward rate. A current model of glass reaction predicts that the glass reaction will be accelerated upon the formation of secondary phases which lower the silicic acid solution concentration. These tests show total Si concentration to increase upon reaction acceleration, however, which may be due to the slightly higher pH attained with the acceleration. The sudden change in the reaction rate is likely due to secondary phase formation. 17 refs, 2 tabs, 3 figs.

Ebert, W.L.; Bates, J.K.; Buck, E.C.; Bradley, C.R.

1992-12-31

257

Critical review of glass performance modeling  

SciTech Connect

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.

Bourcier, W.L. [Lawrence Livermore National Lab., CA (United States)

1994-07-01

258

Room temperature corrosion of museum glass: an investigation using low-energy SIMS  

NASA Astrophysics Data System (ADS)

Glass is often regarded as a stable durable material and the wide range of contemporary applications of glass reinforces this belief. There is nothing inherent in the glassy state, however, that confers stability, and the problem of glass corrosion has been well documented since the 17th century. Glass corrosion still affects commercial float glass production and glasses used to contain high level nuclear waste, but one area in particular where glass corrosion is very common is in the museum environment. In order to conserve these artefacts it is essential to understand fully both the composition of the corroded glass and the corrosion mechanism. In this study, the application of low-energy SIMS for the depth profiling of corroded glass is studied with the aim of finding a suitable environment for the safe storage of glass objects in a museum.

Fearn, Sarah; McPhail, David S.; Oakley, Victoria

2004-06-01

259

Glass material oxidation and dissolution system: Converting miscellaneous fissile materials to glass  

SciTech Connect

The cold war and the development of nuclear energy have resulted in significant inventories of miscellaneous fissile materials (MFMs). MFMs include (1) plutonium scrap and residue, (2) miscellaneous spent nuclear fuel (SNF), (3) certain hot cell wastes, and (4) many one-of-a-kind materials. Major concerns associated with the long-term management of these materials include: safeguards and nonproliferation issues; health, environment, and safety concerns. waste management requirements; and high storage costs. These issues can be addressed by converting the MFMs to glass for secure, long-term storage or repository disposal; however, conventional glass-making processes require oxide-like feed materials. Converting MFMs to oxide-like materials with subsequent vitrification is a complex and expensive process. A new vitrification process has been invented, the Glass Material Oxidation and Dissolution System (GMODS), which directly converts metals, ceramics, and amorphous solids to glass; oxidizes organics with the residue converted to glass; and converts chlorides to borosilicate glass and a secondary sodium chloride (NaCl) stream. Laboratory work has demonstrated the conversion of cerium (a plutonium surrogate), uranium, Zircaloy, stainless steel, multiple oxides, and other materials to glass. However, significant work is required to develop GMODS further for applications at an industrial scale. If implemented, GMODS will provide a new approach to manage these materials.

Forsberg, C.W.; Ferrada, J.J.

1996-03-19

260

Glass in Class  

ERIC Educational Resources Information Center

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…

Greaves, Neville

2005-01-01

261

High-Temperature Studies of Glass Dissolution Rates Close to Saturation  

SciTech Connect

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.

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

2004-06-14

262

Nanoparticle Stained Glass  

NSDL National Science Digital Library

In this activity/demo, learners are introduced to the connection between medieval stained glass artisans and nanotechnology. Learners discover that the red and yellow colors in stained glass windows come from nanoparticles of gold and silver embedded in the glass. This activity/demo consists of two hands-on activities: making a collaborative stained glass window with pre-made nanoparticle solutions containing silver or gold and making a take-away card that contains a small piece of nanoparticle stained “glass."

2014-06-18

263

Radiation coloration resistant glass  

DOEpatents

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.

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

1986-01-01

264

Radiation coloration resistant glass  

DOEpatents

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.

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

1986-11-04

265

High-temperature glass and glass coatings  

NASA Technical Reports Server (NTRS)

Reaction-cured glasses resist thermal shock and maintain properties over range of -100 degrees Centrigrade to +1,480 degrees Centigrade. Stability makes these excellent materials for high-temperature glassware and tubing or as coatings for porous materials.

Goldstein, H. E.; Katvala, V. E.; Leiser, D. B.

1977-01-01

266

Standard test method for determining liquidus temperature of immobilized waste glasses and simulated waste glasses  

E-print Network

1.1 These practices cover procedures for determining the liquidus temperature (TL) of nuclear waste, mixed nuclear waste, simulated nuclear waste, or hazardous waste glass in the temperature range from 600°C to 1600°C. This method differs from Practice C829 in that it employs additional methods to determine TL. TL is useful in waste glass plant operation, glass formulation, and melter design to determine the minimum temperature that must be maintained in a waste glass melt to make sure that crystallization does not occur or is below a particular constraint, for example, 1 volume % crystallinity or T1%. As of now, many institutions studying waste and simulated waste vitrification are not in agreement regarding this constraint (1). 1.2 Three methods are included, differing in (1) the type of equipment available to the analyst (that is, type of furnace and characterization equipment), (2) the quantity of glass available to the analyst, (3) the precision and accuracy desired for the measurement, and (4) candi...

American Society for Testing and Materials. Philadelphia

2011-01-01

267

Diamond turning of glass  

SciTech Connect

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

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

1988-12-01

268

Chalcogenide glass microsphere laser.  

PubMed

Laser action has been demonstrated in chalcogenide glass microsphere. A sub millimeter neodymium-doped gallium lanthanum sulphide glass sphere was pumped at 808 nm with a laser diode and single and multimode laser action demonstrated at wavelengths between 1075 and 1086 nm. The gallium lanthanum sulphide family of glass offer higher thermal stability compared to other chalcogenide glasses, and this, along with an optimized Q-factor for the microcavity allowed laser action to be achieved. When varying the pump power, changes in the output spectrum suggest nonlinear and/or thermal effects have a strong effect on laser action. PMID:21165022

Elliott, Gregor R; Murugan, G Senthil; Wilkinson, James S; Zervas, Michalis N; Hewak, Daniel W

2010-12-01

269

Containerless processing of glass  

NASA Technical Reports Server (NTRS)

Ground-based research on the containerless melting of glass and experiments performed during a flight on the SPAR 6 are described. Experiments leading to selection of the flight sample composition, a silica-modified gallia/calcia glass, and the preparation of a one quarter inch diameter flight sample are described. During the flight experiment, a sample of the glass was containerless melted and cooled to a clear glass in a single axis acoustic positioning apparatus. The functioning of the flight experimental hardware was evaluated. The evaluation of the sample is presented.

Happe, R. A.

1981-01-01

270

Drugstore Reading Glasses  

NASA Astrophysics Data System (ADS)

The occasion for this paper was my reading of a paper in the February 2005 issue of TPT. As one gets older the near point of the eye begins to recede.2 This is called presbyopia.3 An alternative to purchasing glasses from an optometrist is to purchase an inexpensive pair of reading glasses in a pharmacy. The pharmacy has these glasses ordered by diopters corresponding to the strength of the lens needed for a particular presbyopic eye. The glasses are, of course, not available for myopic eyes.

Erlichson, Herman

2006-03-01

271

Apollo 15 green glasses.  

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

272

Glass--Sand + Imagination  

NASA Astrophysics Data System (ADS)

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.

Kolb, Kenneth E.; Kolb, Doris K.

2000-07-01

273

Pressure dependence of glass transition temperature of elastomeric glasses  

Microsoft Academic Search

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

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

1984-01-01

274

Rare Earth Phosphate Glass and Glass-Ceramic Proton Conductors  

SciTech Connect

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.

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

2008-12-03

275

Glasses for Children  

MedlinePLUS

... is a need for glasses, or whether the condition can be monitored. What are the different types of refractive errors (need for glasses) that can affect children? There are 4 basic types of refractive errors: • Myopia (near-sighted) – This is a condition where the distance vision is blurred, but a ...

276

Stained Glass Glue  

NSDL National Science Digital Library

In this activity on page 6 of the PDF, learners use glue instead of glass to create artwork that can be hung in a window. Discover how the chemicals in various materials mix together to make a colorful, translucent "stained glass" creation.

American Chemical Society

2001-01-01

277

Getting Started with Glass  

ERIC Educational Resources Information Center

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…

White, Heather

2007-01-01

278

Disappearing Glass Rods  

NSDL National Science Digital Library

In this optics activity, learners discover how they can make glass objects "disappear." Learners submerge glass objects like stirring rods into a beaker of Wesson™ oil to explore how the principles of reflection and refraction affect what we see. Use this activity as a demonstration or allow learners to experiment on their own.

2011-12-05

279

Corning Museum of Glass  

NSDL National Science Digital Library

The Corning Museum has a website that contains images from part of their 45,000 item historical and art glass collection. The collection spans 3,500 years, and includes "The Origins of Glassmaking", "Asian Glass", "Glass in America", and "Glass After 1960". Visitors can search or browse the collection by the name of the artist or maker, the date made, location made, or the name of the object. One of the "Current Exhibitions" that has some fantastic images of glass objects is the "Medieval Glass for Popes, Princes, and Peasants" exhibit that can be found via their homepage. Visitors interested in seeing images and reading about the history behind medieval glass, should click on the "Medieval Glass Story". The first image, of a cage cup, is a stunning piece from the early fourth century. The last image of the exhibit, entitled "Nef", is Venetian and looks like an elaborate ship with a spout on top of a conical base. Visitors who would like to hear an audio tour of the exhibit should click on "Audio Tour" to listen to any of the 20 short segments explaining the exhibit.

280

Surface Conductive Glass.  

ERIC Educational Resources Information Center

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)

Tanaka, John; Suib, Steven L.

1984-01-01

281

Oxide glass structure evolution under swift heavy ion irradiation  

NASA Astrophysics Data System (ADS)

The effects of ion tracks on the structure of oxide glasses were examined by irradiating a silica glass and two borosilicate glass specimens containing 3 and 6 oxides with krypton ions (74 MeV) and xenon ions (92 MeV). Structural changes in the glass were observed by Raman and nuclear magnetic resonance spectroscopy using a multinuclear approach (11B, 23Na, 27Al and 29Si). The structure of irradiated silica glass resembles a structure quenched at very high temperature. Both borosilicate glass specimens exhibited depolymerization of the borosilicate network, a lower boron coordination number, and a change in the role of a fraction of the sodium atoms after irradiation, suggesting that the final borosilicate glass structures were quenched from a high temperature state. In addition, a sharp increase in the concentration of three membered silica rings and the presence of large amounts of penta- and hexacoordinate aluminum in the irradiated 6-oxide glass suggest that the irradiated glass is different from a liquid quenched at equilibrium, but it is rather obtained from a nonequilibrium liquid that is partially relaxed by very rapid quenching within the ion tracks.

Mendoza, C.; Peuget, S.; Charpentier, T.; Moskura, M.; Caraballo, R.; Bouty, O.; Mir, A. H.; Monnet, I.; Grygiel, C.; Jegou, C.

2014-04-01

282

The leaching behavior of borate waste glass SL-1  

SciTech Connect

Vitrification is an attractive approach for treatment of the borate waste from nuclear power plants. SL-1 glass is a suitable borosilicate glass form to solidify the borate waste containing relatively high quantities of B and Na. The leaching behavior of SL-1 glass in deionized water has been investigated. Compared to the HLW-glass, the network structure of SL-1 glass is weak. It was found that the ion-exchange reactions dominated the glass corrosion process with water in low temperature leading conditions. The ion-exchange and network hydrolysis reactions together controlled the glass dissolution in high temperature leaching conditions. There was a peak in leach rate at about 70 C and a valley at about 100 C. The surface layer thickness was about 25 [micro]m. Na was almost totally depleted in the surface layer. At low temperature, the glass corrosion increases with leaching time. The glass corrosion remains about constant with leaching time at 90 C. The surface layer formed at 90 C is protective, which is less porous than the surface layer formed at 40 and 70 C.

Sheng, J. (Kyoto Univ., Osaka (Japan)); Luo, S.; Tang, B. (China Inst. of Atomic Energy, Beijing (China))

1999-01-01

283

The leaching behavior of borate waste glass SL-1  

SciTech Connect

Vitrification is an attractive approach for treatment of the borate waste from nuclear power plants. SL-1 glass is a suitable borosilicate glass form to solidify the borate waste containing relatively high quantities of B and Na. The leaching behavior of SL-1 glass in deionized water has been investigated. Compared to the HLW-glass, the network structure of SL-1 glass is weak. It was found that the ion-exchange reactions dominated the glass corrosion process with water in low temperature leading conditions. The ion-exchange and network hydrolysis reactions together controlled the glass dissolution in high temperature leaching conditions. There was a peak in leach rate at about 70 C and a valley at about 100 C. The surface layer thickness was about 25 {micro}m. Na was almost totally depleted in the surface layer. At low temperature, the glass corrosion increases with leaching time. The glass corrosion remains about constant with leaching time at 90 C. The surface layer formed at 90 C is protective, which is less porous than the surface layer formed at 40 and 70 C.

Sheng, J. [Kyoto Univ., Osaka (Japan)] [Kyoto Univ., Osaka (Japan); Luo, S.; Tang, B. [China Inst. of Atomic Energy, Beijing (China)] [China Inst. of Atomic Energy, Beijing (China)

1999-11-01

284

Defense HLW Glass Degradation Model  

SciTech Connect

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.

D. Strachan

2004-10-20

285

Engineering Glass Passivation Layers -Model Results  

SciTech Connect

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.

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

2011-08-08

286

Origin and consequences of silicate glass passivation by surface layers  

PubMed Central

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

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

2015-01-01

287

Origin and consequences of silicate glass passivation by surface layers.  

PubMed

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

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

2015-01-01

288

Origin and consequences of silicate glass passivation by surface layers  

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

289

Examination of subaerially altered basaltic glass with TEM and EELS  

SciTech Connect

We have examined the weathered surfaces of 720 year old Hawaiian basalt glasses that were recovered from a subaerial environment with high-resolution transmission electron microscopy (TEM) and energy filtered imaging and electron energy loss spectroscopy (EELS) techniques. Whereas the alteration products (palagonite) were physically detached from the underlying glass in most samples, a gel-like amorphous layer was observed adjacent to the glass in a few samples. To our knowledge, this is the first time a gel layer has been observed on weathered basalt. This is significant because analogous gel layers have been observed on nuclear waste glasses reacted in laboratory tests, and this demonstrates an important similarity in the mechanisms of the weathering of basalt and the corrosion of waste glasses.

Luo, J.-S.

1998-06-17

290

PbO-free glasses for low temperature packaging  

SciTech Connect

Zinc polyphosphate glasses were examined as potential candidates for low temperature sealing applications. Glass-formation and properties were determined for the ZnO-P{sub 2}O{sub 5}, ZnO-B{sub 2}O{sub 3}-P{sub 2}O{sub 5} and ZnO-SnO-P{sub 2}O{sub 5} systems, and information about the short-range structures of these glasses was obtained by Raman and solid state nuclear magnetic resonance spectroscopies. In general, the most durable polyphosphate glasses have structures based on relatively short pyrophosphate chain lengths (i.e., 2 P-tetrahedra). Modified phosphate compositions are given, including compositions used to seal float glass substrates at temperatures as low as 500{degrees}C.

Brow, R.K.; Bencoe, D.N.; Tallant, D.R. [and others

1997-10-01

291

Assessment of water/glass interactions in waste glass melter operation  

SciTech Connect

A study was made to assess the possibility of a vapor explosion in a liquid-fed glass melter and during off-standard conditions for other vitrification processes. The glass melter considered is one designed for the vitrification of high-level nuclear wastes and is comprised of a ceramic-lined cavity with electrodes for joule heating and processing equipment required to add feed and withdraw glass. Vapor explosions needed to be considered because experience in other industrial processes has shown that violent interactions can occur if a hot liquid is mixed with a cooler, vaporizable liquid. Available experimental evidence and theoretical analyses indicate that destructive glass/water interactions are low probability events, if they are possible at all. Under standard conditions, aspects of liquid-fed melter operation which work against explosive interactions include: (1) the aqueous feed is near its boiling point; (2) the feed contains high concentrations of suspended particles; (3) molten glass has high viscosity (greater than 20 poise); and (4) the glass solidifies before film boiling can collapse. While it was concluded that vapor explosions are not expected in a liquid-fed melter, available information does not allow them to be ruled out altogether. Several precautionary measures which are easily incorporated into melter operation procedures were identified and additional experiments were recommended.

Postma, A.K.; Chapman, C.C.; Buelt, J.L.

1980-04-01

292

CCMR: Study of Mixed Glass Former Phenomena in Glasses  

NSDL National Science Digital Library

Water concentration in varying compositions of sodium borosilicate glass was studied by Fourier Transform Infrared Spectroscopy. This is to further explore the Mixed Glass Former Effect (MGFE) in glasses with two or more network formers. Previous data shows that the water concentration increases with time.1 Thick and thin sample analysis was carried out on the glass to validate this data.

Clark, Braeden

2009-08-15

293

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

E-print Network

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

Maddox, W. Todd

294

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

E-print Network

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

Maddox, W. Todd

295

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

E-print Network

Glass, Brian 1 BRIAN DANIEL GLASS, M.A. University Department of Psychology, A8000 The University of Texas at Austin Austin, TX 78712 (512) 232-2883 e-mail: glass@mail.utexas.edu EDUCATION 2006 ­ Cognitive include: Designing and constructing experiments, statistical #12;Glass, Brian 2 analysis, manuscript

Maddox, W. Todd

296

The fate of silicon during glass corrosion under alkaline conditions: A mechanistic and kinetic study with the International Simple Glass  

NASA Astrophysics Data System (ADS)

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 29SiO2. 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 amorphous alteration layer. The mechanisms responsible for this transformation are water penetration 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 is mostly inherited 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 the retroaction of the alteration layer on water dynamics/reactivity at the reaction front, 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 promoted by OH- and the precipitation of CSH and zeolites. This study provides key information for a unified model for glass dissolution.

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

2015-02-01

297

The glass transition diagram in model metallic glasses  

E-print Network

We report a strain rate (equivalent to experimental observation time) induced glass transition in model SrCaYbMg(Li)Zn(Cu) metallic glasses at room temperature. A critical strain rate, equivalent to glass transition temperature, is found for the strain rate induced a glassy state to liquid-like viscoplastic state translation. The results show that the observation time, equivalent to temperature and stress, is a key parameter for the glass transition. A three-dimension glass transition phase diagram involved in time, temperature and stress in metallic glasses is established for understanding the nature of the metallic glasses.

X. Q. Gao; W. H. Wang; K. Zhao; H. Y. Bai

2013-05-22

298

Glass Ceiling Commission  

NSDL National Science Digital Library

Existing from 1991-1996, the Glass Ceiling Commission was a federally funded commission which considered the "invisible, artificial barriers that prevent qualified individuals from advancing within their organization and reaching full potential." While the term "Glass Ceiling" originally referred to women, it was expanded to also include minorities. The Catherwood Library at the School of Industrial and Labor Relations at Cornell University has electronically archived the reports and findings of the commission, as well as a host of papers written on the Glass Ceiling Commission. The Commission summaries, reports, and findings are annotated, as are the accompanying papers.

United States. Federal Glass Ceiling Commission.

299

Reference commercial high-level waste glass and canister definition.  

SciTech Connect

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.

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

1981-09-01

300

Reference commercial high-level waste glass and canister definition  

NASA Astrophysics Data System (ADS)

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 are presented. The borosilicate glass contained in the stainless steel canister represents the probable type of high level waste product that is 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.

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

1981-09-01

301

Relaxations in spin glasses: similarities and differences from ordinary glasses  

SciTech Connect

Relaxation phenomena have become a major concern in the physics of spin glasses. There are certain resemblances of these relaxation properties to those of ordinary glasses. In this work, we compare the relaxation properties of spin glasses near the freezing temperature with those of glasses near the glass transition temperature. There are remarkable similarities between them and they both are in conformity with two coupled universality relations predicted by a recent model of relaxations in condensed matter.

Ngai, K.L.; Rajagopal, A.K.; Huang, C.Y.

1983-01-01

302

Molecular Mobility in Sugar Glasses  

Microsoft Academic Search

Glasses are liquids that exhibit solid state behavior as a result of their extremely high viscosity. Regarding their application to foods, glasses play a role in the preservation of foods, due to their high viscosity and the concomitant low molecular mobility. This thesis focuses on sugar glasses. Sugar glasses are relevant as model systems for foods that contain sugars and

Dries van den I. J

2000-01-01

303

Pressure dependence of glass transition temperature of elastomeric glasses  

NASA Astrophysics Data System (ADS)

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.

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

1984-11-01

304

Baseline LAW Glass Formulation Testing  

SciTech Connect

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.

Kruger, Albert A. [USDOE Office of River Protection, Richland, WA (United States); Mooers, Cavin [The Catholic University of America, Washington, DC (United States). Vitreous State Lab.; Bazemore, Gina [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Pegg, Ian L. [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Hight, Kenneth [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Lai, Shan Tao [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Buechele, Andrew [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Rielley, Elizabeth [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Gan, Hao [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Muller, Isabelle S. [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Cecil, Richard [The Catholic University of America, Washington, DC (United States). Vitreous State Lab

2013-06-13

305

Seeing Glass Contractors Clearly.  

ERIC Educational Resources Information Center

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)

Deliberato, Jerry

2003-01-01

306

CCMR: Water in Glass  

NSDL National Science Digital Library

Water uptake for various compositions of the model glass (Fe2O3)0.01(B2O3)0.048(Na2O)0.142(SiO2)0.8x(Al2O3)0.8(1?x) under fixed annealing conditions was studied via FTIR. Glasses of this formulation were found to take up water at both 300 and 380 °C. The time dependence of their water uptake entails that the governing kinetics are determined by the diffusion of water molecules in the glass network. The experimental approach used was validated by confirming previous water concentration results regarding glasses of the composition (Na2O)0.2[(BO1.5)x(SiO2)1?x]0.8.

Harrell, Stuart

2010-08-15

307

Whisker reinforced glass ceramic  

SciTech Connect

The process for making an in-situ whisker reinforced glass-ceramic that is up to 1.5 times as strong as conventional glass-ceramics was developed at Virginia Tech and patented in 1993. This technology has been identified as having commercial potential for use in high temperature heat exchanger applications for the electric power generation field by the National Center for Appropriate Technology (NCAT). This technology was licensed by MATVA, Inc., a small Virginia business, for further development. In particular, the goal of this project was to develop a property database and conduct initial testing of heat exchanger prototypes to demonstrate its potential application. This final report describes how the glass precursor was formed, physical properties of the glass-ceramic, techniques for making heat exchanger prototypes.

Hirschfeld, D.A.; Brown, J.J. Jr.

1996-06-03

308

Glasses and Contact Lenses  

MedlinePLUS

... together the way they should. But eyeglasses or contact lenses, also called corrective lenses, can help most ... trouble, it's often a refractive problem. Glasses or contact lenses work so well because they can correct ...

309

THE COLOR GLASS CONDENSATE.  

SciTech Connect

The Color Glass Condensate is a state of high density gluonic matter which controls the high energy limit of hadronic interactions. Its properties are important for the initial conditions for matter produced at RHIC.

MCLERRAN,L.

2001-08-26

310

Glass formation in microgravity  

NASA Technical Reports Server (NTRS)

An account is given of containerless glass-forming experiments conducted aboard the Space Shuttle in 1985, using a single-axis acoustic levitator furnace apparatus. An attempt was made to obtain quantitative evidence for the suppression of heterogeneous nucleation/crystallization in containerless melts under microgravity conditions, as well as to study melt homogenization in the absence of gravity-driven convection and assess the feasibility of laser fusion target glass microsphere preparation with a microgravity apparatus of the present type. A ternary calcia-gallia-silica glass thus obtained indicated a 2-3-fold increase in glass-formation tendency for this material composition in microgravity, by comparison with 1g.

Ray, C. S.; Day, D. E.

1987-01-01

311

Microstructuring of Photosensitive Glass  

NASA Astrophysics Data System (ADS)

Femtosecond laser direct writing followed by thermal treatment and successive wet etching can form three-dimensional (3D) hollow microstructures inside photosensitive glass. The principles and procedures of this process are explained. Next, the fabrication of 3D microfluidic structures and optical microcomponents is reviewed. Finally, the manufacture of functional microchip devices such as a microfluidic dye laser, optofluidics, and a nano-aquarium by integrating the microcomponents in a single glass chip is demonstrated.

Sugioka, Koji

312

Metallic glass composition  

DOEpatents

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.

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

1986-01-01

313

Containerless synthesis of interesting glasses  

NASA Technical Reports Server (NTRS)

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.

Weinberg, Michael C.

1990-01-01

314

Glasses with ferroelectric phases  

NASA Astrophysics Data System (ADS)

Glasses ceramics, with ferroelectric phases embedded in the glass matrix, were prepared by the melt- quenching through heat-treatments (HT) of silicate, borate and phosphate glasses. Some glasses were heat-treated with the application of an external electric field (TET). The structure and morphology of the samples were studied by X-ray powder diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The dielectric properties, in function of frequency and temperature, were studied and discussed through a three serial of a resistance in parallel with a constant phase element (CPE), two related with the sample surfaces and one with the bulk material, showing that the bulk has the major contribution for the dielectrical characteristics. The temperature dependence of the dc electrical conductivity (?dc), the thermally stimulated depolarization current (TSDC), and the ac conductivity (?ac), measured at 1 kHz, were used to characterize the samples. The structure, the dielectric properties and the electrical conductivity reflect the important role carried out by the base glass the heat-treatment and the electric field during the HT and the ferroelectric phases in the properties of glass-ceramics.

Valente, M. A.; Graça, M. P. F.

2009-07-01

315

Volcanic Glasses: Construction Materials  

NASA Astrophysics Data System (ADS)

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.

Moskowitz, Samuel E.

1998-01-01

316

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

SciTech Connect

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.

Jantzen, C.M.

1987-01-01

317

DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION  

SciTech Connect

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.

Adamson, D; Bradley Pickenheim, B

2008-11-24

318

Glass microsphere lubrication  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

319

Dissolution of basaltic glass in seawater: Mechanism and rate  

NASA Astrophysics Data System (ADS)

Basaltic glasses are considered as natural analogues for nuclear waste glasses. Thermodynamic computer codes used to evaluate long term behavior of both nuclear waste and basaltic glasses require the knowledge of the dissolution mechanism of the glass network (congruent dissolution or ion exchange in a residual hydrated structure). The paper presents the results of a series of experiments designed to study the structure and chemical composition of alteration layers formed on the surface of artificial tholeiitic glass altered in artificial seawater. Experiments were performed at 60°C, 1 bar and 350 bars in non-renewed conditions. A natural sample from Palagonia (Sicily) has been studied by electron microscopy and comparison between natural and experimental palagonitic layers is made. The behavior of dissolved silica during experiments, and both the structure and the chemical composition of the palagonitic layers, indicate that they form by precipitation of secondary minerals from solution after a total breakdown of the glassy network, i.e., congruent dissolution of the glass. Hence the dissolution equation necessary for thermodynamic modelling of basaltic glass dissolution in seawater at low temperature must be written as a simple stoichiometric process. For the first 2.10 5 years of reaction the palagonitic layers do not constitute a diffusional barrier to the mass transfer between the glass and the bulk solution. The growth of these layers is linearly dependent on time. These experiments indicate that the transformation of glass to palagonitic material is not isovolumetric. Hence it is preferable to use Fe or Ti as conservative elements for chemical budget calculations.

Crovisier, J. L.; Honnorez, J.; Eberhart, J. P.

1987-11-01

320

NMR studies of phosphorus in Si?P?Te and Ge?P?Te glasses  

Microsoft Academic Search

Glass formation and structure in the systems P?Ge?Te and P?Si?Te has been studied by nuclear magnetic resonance (NMR) including 31P magic-angle spinning, spin echo decay spectroscopy, and in situ molten-state investigations. Despite similar regions of glass formation, NMR results illustrate dramatic structural differences between the two systems. In P-Ge-Te glasses homopolar P-P bonding appears to be predominant, while the P-Si-Te

Michael Witschas; Guido Regelsky; Hellmut Eckert

1997-01-01

321

SETTLING OF SPINEL IN A HIGH-LEVEL WASTE GLASS MELTER  

SciTech Connect

High-level nuclear waste is being vitrified, i.e., converted to a durable glass that can be stored in a safe repository for hundreds of thousands of years. Waste vitrification is accomplished in reactors called melters to which the waste is charged together with glass-forming additives. The mixture is electrically heated to a temperature as high as 1150 decrees C to create a melt that becomes glass on cooling.

Pavel Hrma; Pert Schill; Lubomir Nemec

2002-01-07

322

Fabrication and characterization of MCC approved testing material - ATM8 glass  

Microsoft Academic Search

The Materials Characterization Center (MCC) Approved Testing Material ATM-8 is a borosilicate glass that incorporates elements typical of high-level waste (HLW) resulting from the reprocessing of commercial nuclear reactor fuel. Its composition is based upon the simulated HLW glass type 76-68 (Mendel, J.E. et al., 1977, Annual Report of the Characteristics of High-Level Waste Glasses, BNWL-2252, Pacific Northwest Laboratory, Richland,

Wald

1985-01-01

323

Electrical properties of phosphate glasses  

NASA Astrophysics Data System (ADS)

Investigation of the electrical properties of phosphate glasses where transition metal oxide such as iron oxide is the network former and network modifier is presented. Phosphate glasses containing iron are electronically conducting glasses where the polaronic conduction is due to the electron hopping from low to high iron valence state. The identification of structural defects caused by ion/polaron migration, the analysis of dipolar states and electrical conductivity in iron phosphate glasses containing various alkali and mixed alkali ions was performed on the basis of the impedance spectroscopy (IS). The changes in electrical conductivity from as-quenched phosphate glass to fully crystallized glass (glass-ceramics) by IS are analyzed. A change in the characteristic features of IS follows the changes in glass and crystallized glass network. Using IS, the contribution of glass matrix, crystallized grains and grain boundary to the total electrical conductivity for iron phosphate glasses was analyzed. It was shown that decrease in conductivity is caused by discontinuities in the conduction pathways as a result of the disruption of crystalline network where two or more crystalline phases are formed. Also, phosphate-based glasses offer a unique range of biomaterials, as they form direct chemical bonding with hard/soft tissue. The surface charges of bioactive glasses are recognized to be the most important factors in determining biological responses. The improved bioactivity of the bioactive glasses as a result of the effects of the surface charges generated by electrical polarization is discussed.

Mogus-Milankovic, A.; Santic, A.; Reis, S. T.; Day, D. E.

2009-07-01

324

Tin Valence and Local Environments in Silicate Glasses as Determined From X-ray Absorption Spectroscopy  

SciTech Connect

X-ray absorption spectroscopy (XAS) was used to characterize the tin (Sn) environments in four borosilicate glass nuclear waste formulations, two silicate float glasses, and three potassium aluminosilicate glasses. Sn K-edge XAS data of most glasses investigated indicate Sn4+O6 units with average Sn-O distances near 2.03 Angstroms. XAS data for a float glass fabricated under reducing conditions show a mixture of Sn4+O6 and Sn2+O4 sites. XAS data for three glasses indicate Sn-Sn distances ranging from 3.43 to 3.53 Angstroms, that suggest Sn4+O6 units linking with each other, while the 4.96 Angstroms Sn-Sn distance for one waste glass suggests clustering of unlinked Sn4+O6 units.

McKeown,D.; Buechele, A.; Gan, H.; Pegg, I.

2008-01-01

325

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  

Microsoft Academic Search

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

Razi A. Hassan

1991-01-01

326

Fibrous glass and cancer.  

PubMed

Some argue that fibrous glass (glass wool) should not be considered as a likely human carcinogen and hence should not be listed in the Seventh Annual Report on Carcinogens (ARC) prepared by the National Toxicology Program (NTP) and mandated by the U.S. Congress. In examining this issue, data from both laboratory experiments (animal studies) and epidemiologic studies (human data) are reviewed with the results evaluated according to the criteria established by the International Agency for Research on Cancer (IARC) and adopted in slightly modified form by the NTP for classifying substances as human carcinogens or likely human carcinogens. From our comprehensive review of the available information, we conclude that fibrous glass materials are carcinogenic, and in view of the NTP and IARC definitions should be listed in the ARC. Our review then examines the carcinogenic potency of glass fibers to humans in comparison with asbestos fibers and concludes that on a fiber-per-fiber basis, glass fibers may be as potent or even more potent than asbestos. The implications of these findings are then presented for regulatory purposes in the occupational setting. PMID:7810554

Infante, P F; Schuman, L D; Dement, J; Huff, J

1994-10-01

327

Museum of Glass  

NSDL National Science Digital Library

The Museum of Glass in Tacoma, Washington maintains a well crafted website for their spectacular museum. Founded in part by the famous glass artist Dale Chihuly, a Tacoma native, this museum highlights glass artists from the Pacific Northwest. Visitors won't want to miss any of the breathtaking online exhibits on this website, but one of the most spectacular is the "Chihuly Bridge of Glass" under the "Exhibitions & Collections" tab, in the "Outdoor Art" link. The slideshow of five photos shows a 500-foot pedestrian bridge that connects the Museum to downtown Tacoma. The bridge is composed of three distinct sections, one of which allows visitors to "experience a seemingly underwater world of glass shapes and forms a few feet above their heads." Also found under the "Exhibitions & Collections" tab, in the "Current Exhibitions" link, visitors will enjoy a multimedia treatment of the work "Glimmering Gone". Visitors can listen to poems by university students inspired by the exhibit, watch a "Residency" video of the artist who created the work, and view a video tour of the catalog for the exhibit.

328

Multicomponent aluminosilicate glasses: Structure and acid corrosion  

NASA Astrophysics Data System (ADS)

The structure, acid durability, and surface layer formation of two series of fully polymerized aluminosilicate glasses with (CaO+Na2O):(Al 2O3) molar ratios of unity were examined. In particular, the effects of varying the network composition (Al2O3:SiO 2) on bulk glass structure, acid dissolution rate, and surface layer structure were determined. Surface layer formation and structure was investigated using a host of analytical techniques as a function of these compositional variables. It is shown that although the (CaO+Na2O):(Al2O 3) molar ratio remains unity throughout the series, a fully polymerized structure (expected based on "traditional" glass structure models) could not be validated. Bulk glass structures were determined experimentally with ultra-violet Raman spectroscopy (UV-Raman), infrared absorption spectroscopy (IR-absorption), and 29Si magic angle spinning nuclear magnetic resonance (29Si MAS-NMR), and were modeled with molecular dynamic (MD) simulations. The relative concentration of network bonding structures including: non-bridging oxygen (NBO) species, Al-O-Al bonding, and oxygen triclusters, were determined. These characteristics were used to explain dissolution rate, modifier release rate, and surface layer formation of the glasses when exposed to acid. Dissolution rate decreases with increasing Si-O-Si concentration. Dissolution and surface layer formation were the result of breaking network forming bonds (Al-O-Si and Al-O-Al), release of aluminum, sodium, and calcium at equal rates, and rapid re-polymerization of insoluble silica. The surface layers did not form through diffusion-limited ion-exchange between proton-bearing solution species and modifier ions within the glass. The transformed surface layers were found to be microporous, more structurally ordered than the bulk glass, and to contain primarily 3-membered and 4-membered silicate rings (with terminal silanols and trapped molecular water). The processes involved in the layer transformation were simulated using MD, and the resultant layer structures were consistent with the experimental 29Si MAS-NMR results; specifically localized condensation (relaxation) of insoluble silica as the reaction proceeds into the bulk glass.

Mellott, Nathan Petteys

329

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

SciTech Connect

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.

Jantzen, C.M. (Westinghouse Savannah River Co., Aiken, SC (USA)); Ramsey, W.G. (Clemson Univ., SC (USA). Dept. of Ceramic Engineering)

1989-01-01

330

Transient nucleation in glasses  

NASA Technical Reports Server (NTRS)

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.

Kelton, K. F.

1991-01-01

331

Glass enamel and glass-ceramic coatings for chemical apparatus  

Microsoft Academic Search

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

A. S. Eskov; M. I. Oleinik; E. A. Shabrova

1984-01-01

332

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...

333

Synthesis and Vitrification of Nasicon Type Lithium Borophosphate Glasses  

NASA Astrophysics Data System (ADS)

NASICON type Li ion conducting Lithium borophosphate (Li3B2(PO4)3) and lead doped lithium borophosphate (Li3+xPbxB2-x(PO4)3 x = 0.2, 0.4, 0.6, 0.8) glass electrolyte has been prepared by melt quenching method. The effect of lead on the structure of the Lithium borophosphate glass network has been studied by Raman and 31P MAS Nuclear Magnetic resonance analysis. The behavior of the glass transition and electrical conductivity has been interpreted as a function of structural changes induced in the glass network when lead is doped in the Lithium borophosphate by means of DSC and ac impedance spectroscopic technique.

Nithya, H.; Kawamura, Junichi; Iwai, Yoshiki; Takekawa, Reiji; Kuwata, Naoaki; Matsuda, Yasutaka

2013-07-01

334

Toward acceptance of DWPF glass at a Federal Repository  

SciTech Connect

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.

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

1987-01-01

335

Attenuation of Glass Dissolution in the Presence of Natural Additives  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

336

Recent experimental advances in spin glasses  

SciTech Connect

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.

Huang, C.Y.

1983-01-01

337

Glass and ceramics. [lunar resources  

NASA Technical Reports Server (NTRS)

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.

Haskin, Larry A.

1992-01-01

338

Enthalpy of diaplectic labradorite glass  

Microsoft Academic Search

Enthalpies of solution in molten 2PbO·B2O3 at ~988 K have been measured for diaplectic labradorite glass from the Manicouagan impact crater and a fused glass formed from the same material. The enthalpies of solution of the diaplectic and fusion-formed glasses are 4,347 and 2,023 cal mol-1, respectively. The more endothermic enthalpy of solution of the diaplectic glass indicates a greater

K. L. Geisinger; A. Navrotsky; J. Arndt

1986-01-01

339

Spectroscopic studies of glass structure  

SciTech Connect

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.

Brow, R.K.

1994-08-01

340

Strength of glass (a review)  

Microsoft Academic Search

After defining the termglass, brief consideration is given to the theories of glass structure which have been propounded. That glass, in practice, is very much weaker than its theoretical strength predicts is established, and the prime factor for this is shown to be the surface condition of the glass. Surface defects which are accentuated by heat treatment or other processes

B. Sugarman

1967-01-01

341

Physics of glass manufacturing processes  

Microsoft Academic Search

After briefly describing some general features of continuous glass manufacturing processes, the article reviews advances in the theoretical understanding of these processes with particular emphasis on those aspects which involve an interaction between heat transfer and fluid flow. The following topics are included: radiation heat transfer in the large thicknesses of glass encountered in glass melting furnaces, heat transfer in

H. Rawson

1974-01-01

342

Barstow heliostat mirror glass characterization  

SciTech Connect

The technical analysis performed on the special run of low iron float glass procured from the Ford Glass Division for the ten megawatt solar thermal/electric pilot power plant to be constructed at Barstow, California is discussed. The topics that are addressed include the optical properties and the relative durability of the glass. Two optical parameters, solar transmittance and optical flatness, were measured as referenced in the specification and found to be better than the stated tolerances. The average solar transmittance exceeded 0.890 transmittance units. The glass also exhibited optical angular flatness deviations less than +-1.0 mrad as required. Both qualitative and quantitative accelerated weathering tests were performed on the glass in order to compare its durability to other soda lime float glass and alternate composition glasses of interest to the solar community. In both the quantitative leaching experiments and the more qualitative room temperature and elevated temperature water vapor exposure experiments the heliostat glass exhibited the same characteristics as the other soda-lime silicate float glasses. As a final test for mirroring compatability, selected samples of the production run of the glass were sent to four different commercial manufacturers for mirror coating. None of the manufacturers reported any difficulty silvering the glass. Based on the tests performed, the glass meets or exceeds all optical specifications for the Barstow heliostat field.

Lind, M.A.; Buckwalter, C.Q.

1980-09-01

343

Yesterday's Trash Makes Tomorrow's "Glass"  

ERIC Educational Resources Information Center

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…

Wayne, Dale

2010-01-01

344

Stained-Glass Pastels  

ERIC Educational Resources Information Center

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…

Laird, Shirley

2009-01-01

345

The Color Glass Condensate  

E-print Network

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.

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

2010-02-01

346

"Stained Glass" Landscape Windows  

ERIC Educational Resources Information Center

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…

Vannata, Janine

2008-01-01

347

Local and Medium Range Order Around Fission Products in Inactive Waste Glasses: Implication for Glass Structure and Stability  

NASA Astrophysics Data System (ADS)

Borosilicate glasses are used to store high level nuclear waste in France (R7T7 glass). The structure of the glass around elements such as fission products controls important parameters as the homogeneity of the glass and/or the melted glass rheology. Data on the local and medium range order structure of these glasses could help improving the resistance toward leaching and/or irradiation, in relation with surface or geological storage of these vitrified wastes. Due to the complex composition of these glasses (up to 30 oxides), chemically selective methods are required to understand the environment of elements. X-ray Absorption Spectroscopy (XAS) is, from this point of view, a powerful tool as it provides a direct access to the investigation of the structure around specific cations in this multicomponent amorphous material, to specify their role in the glass durability. We will present different XAS studies (synchrotrons in LURE and ESRF, France) on the inactive amorphous analog for the R7T7 glass (the SON 68 glass). This report will illustrate the potentialities of this approach through the determination of the environment around fission products such as Zr, Zn and Mo. XAS shows the peculiarity of the sites occupied by these glass components of technological interest. Coordination numbers are shown to be systematically smaller than in crystalline compounds with close composition. Below the definition of the sites occupied by the chemical elements, XAS allows to detect some degree of medium range order which gives insight on the bonding of the site to the poymeric borosilicate network and allow to link precisely experimental data to theoretical calculations. Eventually, XAS is used to study the interaction between noble metals (Pd and Ru) and the glassy matrix. These elements are at the origin of small precipitates that induce changes in the melt vicosity. They occur as a result of the non-insertion of these elements in the glassy matrix. To accurate and precise structural interpretations, a direct comparison with MD calculations on simplified nuclear glass comprising 5 oxides, is performed.

Galoisy, L.; Calas, G.; Ghaleb, D.; Morin, G.

2002-12-01

348

THE DEVELOPMENT OF RADIOACTIVE GLASS SURROGATES FOR FALLOUT DEBRIS  

SciTech Connect

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.

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

2014-01-01

349

Volcanic glass as a natural analog for borosilicate waste glass  

SciTech Connect

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.

Morgenstein, M.E.; Shettel, D.L. [Geosciences Management Institute, Inc., Boulder City, NV (United States)

1994-12-31

350

Bioactive calcium pyrophosphate glasses and glass-ceramics.  

PubMed

Calcium phosphate glass-based materials in the pyrophosphate region are briefly reviewed. Calcium pyrophosphate glasses can be prepared by including a small amount of TiO(2) (glasses in simulated body fluid. By heating powder-compacts of the glasses, they are crystallized and subsequently are sintered, resulting in fabrication of high-strength glass-ceramics with machinability; they are easier to be machined using conventional tools in comparison with conventional calcium phosphate ceramics. beta-Ca(2)P(2)O(7) crystal formed in the glass-ceramics plays an important role in the machinability. Their apatite-forming ability in simulated body fluid is drastically enhanced after autoclaving in distilled water. The glass-ceramics can be easily coated on a new beta-type titanium alloy using a conventional glazing technique. PMID:16701780

Kasuga, Toshihiro

2005-01-01

351

Design and operation of a 100 kg\\/h electric melter for nuclear-waste vitrification  

Microsoft Academic Search

The proposed use of ceramic-lined, electric-heated glass melters for the vitrification of nuclear wastes requires careful adaptation of commercial glass furnace practices. The vitrification of simulated nuclear waste calcines was studied in a ceramic-lined melter with a glass surface area of 0.76 m². The melter contained 0.25 m³ of glass, which was heated by the flow of an ac current

Dierks

1980-01-01

352

Influence of La2O3 Additions on Chemical Durability and Dielectric Properties of Boroaluminosilicate Glasses  

NASA Astrophysics Data System (ADS)

Boroaluminosilicate glasses containing La2O3 were prepared by the normal quenching method. The glass transition temperatures (Tg) were measured by differential scanning calorimetry (DSC). The structural role of RO was investigated by nuclear magnetic resonance (NMR). Chemical durability was evaluated by weight losses of glass samples after immersion in HC1 solution. High resolution scanning electron microscopy (HR-SEM) was used to examine the surface micrographs of corroded glass samples. The dielectric constant and tangent loss were measured in the frequency range 10-106 Hz. The results revealed that chemical durability and dielectric properties increased with increasing La2O3 content.

Zhang, X. H.; Yue, Y. L.; Wu, H. T.

2012-12-01

353

Apollo 12 ropy glasses revisited  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

354

Numerical study of XY spin glass and gauge glass models  

NASA Astrophysics Data System (ADS)

We study the +/- J XY spin glass and gauge glass models by a zero temperature domain wall renormalization group method, which enables us to investigate the possibility of an ordered phase at small but finite temperature, that is, to determine the lower critical dimension of the models. The domain wall energy of the system is computed by using the Hamiltonian in the Coulomb gas representation instead of the usual phase representation, since the former is more convenient for our numerical study as it eliminates spin wave contributions to the energy. We reconfirm the earlier prediction in gauge glass that there is no ordered phase in 2d but an ordered phase can exist in 3d at low temperature. However, our simulation yield the stiffness exponents q? --0.35 in 2d and q? +0.30 in 3d, which are considerably larger than the previous estimates but reconcile with the recent finite temperature Monte Carlo study, and strongly suggests that the lower critical dimension, dl, is less than three. In +/- J XY spin glass, there can exist two different glass orders, spin glass and chiral glass orders. It has been numerically suggested the decoupling of the spin and chiral degrees of freedom in both 2 d and 3d, and dl = 4 for spin glass order and 2 < dl < 3 for chiral glass order. We obtain the same stiffness exponents for spin glass and chiral glass in 2d, which suggests that the decoupling does not occur in 2d, which is consistent with the non-rigorous but plausible conjecture. In 3d, our study yields a positive stiffness exponents qs? +0.10 for spin glass. This strongly suggests the lower critical dimension for spin glass order is 2 < dl < 3 as well as a chiral glass order.

Akino, Nobuhiko

355

Lead and aluminum bonding in Pb-AI metaphosphate glasses.  

PubMed

The bonding properties of cations in phosphate glasses determine many short- and medium-range structural features in the glass network, hence influencing bulk properties. In this work, Pb-Al-metaphosphate glasses (1 - x)Pb(PO(3))(2).xAI(PO(3))(3) with 0 < or = x < or = 1 were analyzed to determine the effect of the substitution of Pb by AI on the glass structure in the metaphosphate composition. The glass transition temperature and density were measured as a function of the Al concentration. The vibrational and structural properties were probed by Raman spectroscopy and nuclear magnetic resonance of (31)P, (27)AI, and (207)Pb. Aluminum incorporates homogeneously in the glass creating a stiffer and less packed network. The average coordination number for AI decreases from 5.9 to 5.0 as x increases from 0.1 to 1, indicating more covalent AI-O bonds. The coordination number of Pb in these glasses is greater than 8, showing an increasing ionic behavior for compositions richer in AI. A quantitative analysis of the phosphate speciation shows definite trends in the bonding of AIO(n) groups and phosphate tetrahedra. In glasses with x < 0.48, phosphate groups share preferentially only one nonbridging O corner with an AIO(n) coordination polyhedron. For x > 0.48 more than one nonbridging O can be linked to AIO(n) polyhedra. There is no corner sharing of O between AIO(n) and PbO(n) polyhedra nor between AIO(n) themselves throughout the compositional range. The PbO(n) coordination polyhedra show considerable nonbridging O sharing, with each O participating in the coordination sphere of at least two Pb. The bonding preferences determined for Al are consistent with the behavior observed in Na-AI and Ca-AI metaphosphates, indicating this may be a general behavior for ternary phosphate glasses. PMID:18081273

Tsuchida, J E; Schneider, J; Pizani, P S; Oliveira, S L

2008-01-21

356

NUCLEAR WASTE VITRIFICATION EFFICIENCY COLD CAP REACTIONS  

Microsoft Academic Search

The cost and schedule of nuclear waste treatment and immobilization are greatly affected by the rate of glass production. Various factors influence the performance of a waste-glass melter. One of the most significant, and also one of the least understood, is the process of batch melting. Studies are being conducted to gain fundamental understanding of the batch reactions, particularly those

KRUGER AA; HRMA PR; POKORNY R

2011-01-01

357

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

DOEpatents

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.

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

1985-01-04

358

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

DOEpatents

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.

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

1987-11-10

359

Profiles in garbage glass containers  

SciTech Connect

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.

Miller, C. [Environmental Industry Associations, Washington, DC (United States)

1997-09-01

360

The performance of Glass GEM  

NASA Astrophysics Data System (ADS)

Here we report the performance of Glass gas electron multipliers (Glass GEMs), which were fabricated with photo-etchable glass. The photo-etchable glass used for substrate is called PEG3 (Hoya Corporation). With this material, we succeeded in fabricating a Glass GEM that was 680 ? m-thick with a hole diameter of 170 ? m and Cr and Cu layer electrodes. A Glass GEM has advantages such as good uniformity, high gain, a flat surface without stretching, cylindrical holes, and the absence of outgassing from the material. We successfully operated a Glass GEM having 100 × 100 m 2 effective area with various gas mixtures. The energy resolution for 5.9 keV X-rays was 18%, obtained by uniform irradiation of the entire effective area. The gas gain of the Glass GEM reached up to 90,000 with a gas mixture of Ne/C 4 (90:10). The Glass GEM was also operated with Ar/C 4 and Ar/C 4 gas. The gain stability measured for Glass GEM showed no significant increase or decrease as a function of elapsed time from applying high voltage. The gain stability over 15 hours of operation was about 10% in high-count-rate irradiation. Gain mapping across the Glass GEM showed good uniformity with a standard deviation of about 10%.

Fujiwara, T.; Mitsuya, Y.; Takahashi, H.; Fushie, T.; Kishimito, S.; Guèrard, B.; Uesaka, M.

2014-11-01

361

Nanostructure of glasses: experimental evidence  

NASA Astrophysics Data System (ADS)

Inorganic glass is material having nanoscaled physical and chemical inhomogeneities ad initio because glass inherits thermodynamic fluctuations of concentration, density and anisotropy of a glass forming melt. Combining light scattering and high temperature acoustics data allows to use the effect of internal immersion for designing multicomponent glasses with Rayleigh scattering losses lower than those of the silica glass. Non-random spatial distribution of dopants including rare-earth (RE) ions in a glass host (doped ion segregation) causes excessive Rayleigh scattering losses and enhancement of RE ion-ion interaction. Therefore, it opens the way to optimize operation parameters of laser and up-converting glasses by the proper choice of glass host composition. Results of Raman scattering spectra processing and characterization of electrooptical (EO) sensitivity of niobate glasses showed the existence of groups with stoichiometry of the well-known EO crystals and crystal-like orderliness (crystal motifs) in the glasses as the necessary condition of high EO sensitivity. It was found that EO sensitivity of glasses could be essentially increased by thermal treatment.

Maksimov, Leonid V.; Anan'ev, Anatolii V.; Bogdanov, Victor N.; Lipovskii, Andrey A.; Tagantsev, Dmitri K.; Yanush, Oleg V.

2008-09-01

362

Fluoride glass: Crystallization, surface tension  

NASA Technical Reports Server (NTRS)

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.

Doremus, R. H.

1988-01-01

363

The formation of crystals in glasses containing rare earth oxides  

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

364

Recent results on the effect of gamma radiation on the durability and microstructure of DWPF glass  

SciTech Connect

The effect of gamma radiation on the durability and microstructure of a simulated nuclear waste glass from the Savannah River Site has been carefully investigated. Three large pieces of glass were irradiated with a Co-60 source to three doses up to a maximum dose of 3.1 {times} 10{sup 10} rad. Internal samples of the large pieces of irradiated and unirradiated glass were leached in deionized water to investigate durability changes and were examined by transmission electron microscopy (TEM) to investigate microstructure changes. Leach tests were performed in triplicate at 90{degree}C with crushed glass samples in deionized water. A statistical analysis of the results indicated to the 95% confidence level that the radiation did not affect the glass durability. Careful examination by TEM indicated no effect of gamma radiation on the microstructure of the glass although severe damage could be induced by the electron beam from the microscope. 19 refs., 2 figs., 3 tabs.

Bibler, N.E.; Tosten, M.H.; Beam, D.C.

1989-12-31

365

Recent results on the effect of gamma radiation on the durability and microstructure of DWPF glass  

SciTech Connect

The effect of gamma radiation on the durability and microstructure of a simulated nuclear waste glass from the Savannah River Site has been carefully investigated. Three large pieces of glass were irradiated with a Co-60 source to three doses up to a maximum dose of 3.1 {times} 10{sup 10} rad. Internal samples of the large pieces of irradiated and unirradiated glass were leached in deionized water to investigate durability changes and were examined by transmission electron microscopy (TEM) to investigate microstructure changes. Leach tests were performed in triplicate at 90{degree}C with crushed glass samples in deionized water. A statistical analysis of the results indicated to the 95% confidence level that the radiation did not affect the glass durability. Careful examination by TEM indicated no effect of gamma radiation on the microstructure of the glass although severe damage could be induced by the electron beam from the microscope. 19 refs., 2 figs., 3 tabs.

Bibler, N.E.; Tosten, M.H.; Beam, D.C.

1989-01-01

366

Yb3+ doped fluorophosphate laser glasses with high gain coefficient and improved laser property  

NASA Astrophysics Data System (ADS)

Yb3+ doped fluorophosphate glasses with high stimulated emission cross-section, large gain coefficient and low hydroxyl absorption coefficient were prepared by high temperature melting for fiber laser applications, and their spectral, general laser parameters were investigated accordingly by means of fluorescence emission spectrum, decay cure and infrared absorption spectra. Compared with previously reported fluorophosphate glasses, the investigated fluorophosphate glasses have highest grain coefficient and maintain a maximum laser systematical factor over other various types of laser glasses. The introduction of fluorides to fluorophosphate glasses results in the low level of hydroxyl absorption coefficient and concentration. All these advantages might mean that Yb3+ doped fluorophosphate glasses are a good candidate as an active laser media for short pulse, high power laser generation used for next generation nuclear fusion.

Wang, P. F.; Peng, B.; Li, W. N.; Hou, Ch. Q.; She, J. B.; Guo, H. T.; Lu, M.

2012-04-01

367

Behaviour of ruthenium dioxide particles in borosilicate glasses and melts  

NASA Astrophysics Data System (ADS)

Ruthenium-glass systems are formed during the vitrification of nuclear waste. They are also widely used in micro-electronics because of their unique electrical properties. However, the interaction of this element with the glass matrix remains poorly understood. This work focuses on a RuO 2 particles-nuclear alumino-borosilicate glass system in which the electrical conductivity is known to vary considerably with the RuO 2 content and to become electronic above about 0.5-0.7 vol.% RuO 2 [R. Pflieger, M. Malki, Y. Guari, J. Larionova, A. Grandjean, J. Am. Ceram. Soc., accepted for publication]. Some RuO 2 segregation was observed in SEM/TEM investigations but no continuous chain of RuO 2 particles could be seen. Electron relays between the particles are then necessary for a low-rate percolation, such as the nanoclusters suggested by Adachi et al. [K. Adachi, S. Iida, K. Hayashi, J. Mater. Res. 9 (7) (1994) 1866; K. Adachi, H. Kuno, J. Am. Ceram. Soc. 83 (10) (2000) 2441], which could consist in dissolved ruthenium. Indeed, several observations made here clearly indicate the presence of dissolved ruthenium in the glass matrix, like the modification of the glass density in presence of RuO 2 particles or the diffusion-limited growth of RuO 2 particles in the melt.

Pflieger, Rachel; Lefebvre, Leila; Malki, Mohammed; Allix, Mathieu; Grandjean, Agnès

2009-06-01

368

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

SciTech Connect

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.

None

2012-01-01

369

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

PubMed

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

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

2012-09-28

370

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

NASA Astrophysics Data System (ADS)

Alkali ion charge transport has been studied in a series of mixed glass former lithium borophosphate glasses of composition 0.33Li2O + 0.67[xB2O3 + (1 - x)P2O5]. The entire concentration range, 0.0 ? x ? 1.0, from pure glassy Li2P4O11 to pure glassy Li2B4O7 has been examined while keeping the molar fraction of Li2O 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.

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

2012-09-01

371

CCMR: Water in Glass  

NSDL National Science Digital Library

Water uptake for various compositions of the model glass (CaO·Al2O3)x (2 SiO2)1-x under fixed annealing conditions was studied via FTIR. The water saturation concentration increased with time for certain sample sets, suggesting slow equilibration of the surface with the annealing atmosphere, while the water diffusion coefficient exhibited no appreciable time dependence. The saturation concentration and diffusion coefficient were not found to vary significantly with composition.

Uspal, William

2005-08-17

372

Cluster-assembled metallic glasses  

PubMed Central

A bottom-up approach to nanofabricate metallic glasses from metal clusters as building blocks is presented. Considering metallic glasses as a subclass of cluster-assembled materials, the relation between the two lively fields of metal clusters and metallic glasses is pointed out. Deposition of selected clusters or collections of them, generated by state-of-the-art cluster beam sources, could lead to the production of a well-defined amorphous material. In contrast to rapidly quenched glasses where only the composition of the glass can be controlled, in cluster-assembled glasses, one can precisely control the structural building blocks. Comparing properties of glasses with similar compositions but differing in building blocks and therefore different in structure will facilitate the study of structure–property correlation in metallic glasses. This bottom-up method provides a novel alternative path to the synthesis of glassy alloys and will contribute to improving fundamental understanding in the field of metallic glasses. It may even permit the production of glassy materials for alloys that cannot be quenched rapidly enough to circumvent crystallization. Additionally, gaining deeper insight into the parameters governing the structure–property relation in metallic glasses can have a great impact on understanding and design of other cluster-assembled materials. PMID:23899019

2013-01-01

373

Enthalpy of diaplectic labradorite glass  

NASA Astrophysics Data System (ADS)

Enthalpies of solution in molten 2PbO·B2O3 at ˜988 K have been measured for diaplectic labradorite glass from the Manicouagan impact crater and a fused glass formed from the same material. The enthalpies of solution of the diaplectic and fusion-formed glasses are 4,347 and 2,023 cal mol-1, respectively. The more endothermic enthalpy of solution of the diaplectic glass indicates a greater relative energetic stability of about 2.3 kcal mol-1. The data are consistent with Diemann and Arndt's (1984) structural model that suggests the diaplectic glass is more ordered than fusion-formed glass and with the presence of crystallites. Comparison of data to enthalpies of solution of crystalline labradorite (Carpenter et al. 1985) indicates a maximum percentage of crystalline relics of ˜15 18%, also consistent with Diemann and Arndt's (1984) estimate of <17%. Thus the diaplectic glass is intermediate in thermochemical properties between normal glass and crystal (much closer to glass) and does not represent any state more unstable than normal fusion-formed glass.

Geisinger, K. L.; Navrotsky, A.; Arndt, J.

1986-11-01

374

Structure and Chemistry in Halide Lead-Tellurite Glasses  

SciTech Connect

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.

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

2013-02-11

375

Analytical Plan for Roman Glasses  

SciTech Connect

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.

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

2011-01-01

376

Bioactive glass in tissue engineering  

PubMed Central

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

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

2011-01-01

377

Mixed Glass Former Effect In Silver Molybdophosphate and Borophosphate Glasses  

NASA Astrophysics Data System (ADS)

We report the study of electrical properties of some silver ion conducting molybdophosphate and borophosphate mixed network former glasses in a wide frequency and temperature range. The dc conductivity of the mixed network former glasses is higher than that of the single network former glasses. The ac conductivity spectra show a power law type dependence on frequency. The frequency exponent obtained from ac conductivity is observed to be independent of both temperature and composition.

Deb, B.; Kabi, S.; Ghosh, A.

2011-07-01

378

Structure, biodegradation behavior and cytotoxicity of alkali-containing alkaline-earth phosphosilicate glasses.  

PubMed

We report on the effect of sodium on the structure, chemical degradation and bioactivity of glasses in the CaO-MgO-SiO2-P2O5-CaF2 system. The (29)Si and (31)P magic angle spinning-nuclear magnetic resonance spectroscopy of melt-quenched glasses with varying Na2O/MgO ratios exhibit a silicate glass network with the dominance of Q(2)(Si) units and phosphorus mainly forming orthophosphate species. Sodium incorporation in the glasses did not induce a significant structural change in the silicate network, while it did influence the phosphate environment due to its lower ionic field strength in comparison with that of magnesium. The apatite forming ability of glasses has been investigated by immersion of glass powders in simulated body fluid (SBF) for time durations varying between 1h and 7 days while their chemical degradation has been studied in Tris-HCl in accordance with ISO-10993-14. Increasing Na(+)/Mg(2+) ratio caused a decrease in the chemical durability of glasses and in the apatite forming ability especially during initial steps of interaction between glass and SBF solution. The cellular responses were observed in vitro on bulk glass samples using mouse-derived pre-osteoblastic MC3T3-E1 cell line. The preliminary study suggested that the increasing alkali-concentration in glasses led to cytotoxicity in the cell culture medium. PMID:25280692

Kansal, Ishu; Reddy, AlluAmarnath; Muñoz, Francisco; Choi, Seong-Jun; Kim, Hae-Won; Tulyaganov, Dilshat U; Ferreira, José M F

2014-11-01

379

Mixed polyanion glass cathodes: Iron phosphate vanadate glasses  

SciTech Connect

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.

Kercher, Andrew K [ORNL; Ramey, Joanne Oxendine [ORNL; Carroll, Kyler J [Massachusetts Institute of Technology (MIT); Kiggans Jr, James O [ORNL; Veith, Gabriel M [ORNL; Meisner, Roberta [Oak Ridge National Laboratory (ORNL); Boatner, Lynn A [ORNL; Dudney, Nancy J [ORNL

2014-01-01

380

Long-term alteration of basaltic glass: Mechanisms and rates  

NASA Astrophysics Data System (ADS)

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.

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

2015-04-01

381

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

Code of Federal Regulations, 2013 CFR

...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....

2013-10-01

382

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

Code of Federal Regulations, 2014 CFR

...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....

2014-10-01

383

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

Code of Federal Regulations, 2011 CFR

...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....

2011-10-01

384

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

Code of Federal Regulations, 2012 CFR

...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....

2012-10-01

385

Space processing of chalcogenide glass  

NASA Technical Reports Server (NTRS)

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 is determined. The technique of space processing chalcogenide glass was developed, and the process and equipment necessary to do so was defined. Earthbound processing experiments with As2S3 and G28Sb12Se60 glasses were experimented with. Incorporated into these experiments is the use of an acoustic levitation device.

Larsen, D. C.; Ali, M. I.

1977-01-01

386

Method for heating a glass sheet  

DOEpatents

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.

Boaz, P.T.

1998-07-21

387

Terahertz transmission spectroscopy of chalcogenide glasses  

Microsoft Academic Search

Terahertz transmission of a chalcogenide family of glasses is reported. The glasses were processed using established methods for non-oxide glasses. Transmission through the samples was measured using a THz spectrometer. The transmission and optical properties of the glasses are summarized. The results show promise of these glasses for application as THz windows.

S. K. Sundaram; B. J. Riley; J. V. Crum

2008-01-01

388

Power laser application for security glass production  

Microsoft Academic Search

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

Vladimir Abashkin; Elena Achimova

2009-01-01

389

Method for heating a glass sheet  

DOEpatents

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.

Boaz, Premakaran Tucker (Livonia, MI)

1998-01-01

390

Fabrication of glass microspheres with conducting surfaces  

Microsoft Academic Search

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

Elsholz

1984-01-01

391

Fabrication of glass microspheres with conducting surfaces  

Microsoft Academic Search

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

Elsholz

1982-01-01

392

Crystallization of copper metaphosphate glass  

NASA Technical Reports Server (NTRS)

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.

Bae, Byeong-Soo; Weinberg, Michael C.

1993-01-01

393

Glass corrosion in natural environment  

NASA Technical Reports Server (NTRS)

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.

Thorpe, Arthur N.

1989-01-01

394

Glass Formulation Development for INEEL Sodium-Bearing Waste  

SciTech Connect

For about four decades, radioactive wastes have been collected and calcined from nuclear fuels reprocessing at the Idaho Nuclear Technology and Engineering Center (INTEC), formerly Idaho Chemical Processing Plant (ICPP). Over this time span, secondary radioactive wastes have also been collected and stored as liquid from decontamination, laboratory activities, and fuel-storage activities. These liquid wastes are collectively called sodium-bearing wastes (SBW). About 5.7 million liters of these wastes are temporarily stored in stainless steel tanks at the Idaho National Engineering and Environmental Laboratory (INEEL). Vitrification is being considered as an immobilization step for SBW with a number of treatment and disposal options. A systematic study was undertaken to develop a glass composition to demonstrate direct vitrification of INEEL's SBW. The objectives of this study were to show the feasibility of SBW vitrification, not a development of an optimum formulation. The waste composition is relatively high in sodium, aluminum, and sulfur. A specific composition and glass property restrictions, discussed in Section 2, were used as a basis for the development. Calculations based on first-order expansions of selected glass properties in composition and some general tenets of glass chemistry led to an additive (fit) composition (68.69 mass % SiO{sub 2}, 14.26 mass% B{sub 2}O{sub 3}, 11.31 mass% Fe{sub 2}O{sub 3}, 3.08 mass% TiO{sub 2}, and 2.67 mass % Li{sub 2}O) that meets all property restrictions when melted with 35 mass % of SBW on an oxide basis, The glass was prepared using oxides, carbonates, and boric acid and tested to confirm the acceptability of its properties. Glass was then made using waste simulant at three facilities, and limited testing was performed to test and optimize processing-related properties and confirm results of glass property testing. The measured glass properties are given in Section 4. The viscosity at 1150 C, 5 Pa{center_dot}s, is nearly ideal for waste-glass processing in a standard liquid-fed joule-heated melter. The normalized elemental releases by 7-day PCT are all well below 1 g/m{sup 2}, which is a very conservative set point used in this study. The T{sub L}, ignoring sulfate formation, is less than the 1050 C limit. Based on these observations and the reasonable waste loading of 35 mass 0/0, the SBW glass was a prime candidate for further testing. Sulfate salt segregation was observed in all test melts formed from oxidized carbonate precursors. Melts fabricated using SBW simulants suggest that the sulfate-salt segregation seen in oxide and carbonate melts was much less of a problem. The cause for the difference is likely H{sub 2}SO{sub 4} fuming during the boil-down stage of wet-slurry processing. Additionally, some crucible tests with SBW simulant were conducted at higher temperatures (1250 C), which could increase the volatility of sulfate salts. The fate of sulfate during the melting process is still uncertain and should be the topic of future studies. The properties of the simulant glass confirmed those of the oxide and carbonate glass. Corrosion tests on Inconel 690 electrodes and K-3 refractory blocks conducted at INEEL suggest that the glass is not excessively corrosive. Based on the results of this study, the authors recommend that a glass made of 35% SBW simulant (on a mass oxide and halide basis) and 65% of the additive mix (either filled or raw chemical) be used in demonstrating the direct vitrification of INEEL SBW. It is further recommended that a study be conducted to determine the fate of sulfate during glass processing and the tolerance of the chosen melter technology to sulfate salt segregation and corrosivity of the melt.

J.D. Vienna; M.J. Schweiger; D.E. Smith; H.D. Smith; J.V. Crum; D.K. Peeler; I.A. Reamer; C.A. Musick; R.D. Tillotson

1999-08-03

395

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

SciTech Connect

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.

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

1995-10-23

396

7.G Stained Glass  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: The students in Mr. Rivera's art class are designing a stained-glass window to hang in the school entryway. The window will be 2 feet tall and 5 feet w...

397

Halide laser glasses  

SciTech Connect

Energy storage and energy extraction are of prime importance for efficient laser action and are affected by the line strengths and linewidths of optical transitions, excited-state lifetimes, nonradiative decay processes, spectroscopic inhomogeneities, nonlinear refractive index, and damage threshold. These properties are all host dependent. To illustrate this, the spectroscopic properties of Nd/sup 3 +/ have been measured in numerous oxide, oxyhalide, and halide glasses. A table summarizes the reported ranges of stimulated emission cross sections, peak wavelengths, linewidths, and radiative lifetimes associated with the /sup 4/F/sub 3/2/ ..-->.. /sup 4/I/sub 11/2/ lasing transition.

Weber, M.J.

1982-01-14

398

Glasses on the seabed: surface study of chemical corrosion in sunken Roman glasses  

Microsoft Academic Search

The current work aims to describe surface weathering of ancient glasses in marine environment. All data are collected using different techniques: optical microscopy, RGA, surface techniques (XPS, SEM and SIMS). Three types of glass weathering have been observed: white glass, glossy glass and glass showing growth rings. A compact structure characterizes white glasses, while a porous structure with flaked layers

Barbara Dal Bianco; Renzo Bertoncello; Laura Milanese; Simona Barison

2004-01-01

399

Thermochemical study of rare earth and nitrogen incorporation in glasses  

NASA Astrophysics Data System (ADS)

Rare earth containing aluminosilicate, borosilicate, aluminate and nitrogen containing aluminosilicate glasses are technically important materials. They have extraordinary physical and chemical properties such as high glass transition temperature, very low electrical conductivity, and excellent chemical stability. These unique properties lead to applications as coatings on metals and ceramics, optical fibers, semiconductors, and nuclear waste containment materials. In addition, such systems contain the most widely used additives for sintering of Si3N4, SiAlON and SiC ceramics for high temperature applications. Thermodynamic properties and the relations among energetics, structure and bonding are essential to controlling processing parameters to synthesize, at lower cost, materials having better properties. Earlier investigations mainly pertained to specific physical properties of rare-earth doped oxide and oxynitride glasses. Work on the thermodynamic stability and materials compatibility has been very sparse. High temperature solution calorimetry in molten oxide solvents is a powerful tool for the thermodynamic study of refractory materials. With implementation and improvement, this technique has been applied to the first measurement of enthalpies of formation of RE-Si-Al-O glasses, REAlO3 glasses, RE-Si-Al-O-N glasses, and Si3N 4 and Ge3N4 with high pressure spinel structure. The first successful synthesis of REAlO3 glasses has been achieved by containerless melting. Their large enthalpies of crystallization confirm that they are reluctant glass formers. For glasses along the 2REAlO3 -3SiO2 join, the strongly negative heats of mixing support the absence of miscibility gaps except possibly at very high silica content. Energetic evidence has been presented for incipient phase-ordered regions in Gd- or Hf-containing sodium alumino-borosilicate glasses for plutonium immobilization. Linear relations between enthalpies of formation of RESiAlON glasses from elements and nitrogen content indicate that within the experimental composition range, sites occupied by nitrogen ions are roughly energetically equivalent in a given substitution series. The energetics of difference rare-earth substitution appears to be dominated by differences in the acid/base character of the cations.

Zhang, Yahong

400

POROUS WALL, HOLLOW GLASS MICROSPHERES  

SciTech Connect

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.

Sexton, W.

2012-06-30

401

Solution of naturally-ocurring glasses in the geological environment  

NASA Technical Reports Server (NTRS)

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.

Glass, B. P.

1982-01-01

402

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

SciTech Connect

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

Fox, K.; Marra, J.

2014-08-14

403

7 CFR 3201.30 - Glass cleaners.  

Code of Federal Regulations, 2012 CFR

...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,...

2012-01-01

404

7 CFR 2902.30 - Glass cleaners.  

Code of Federal Regulations, 2010 CFR

...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,...

2010-01-01

405

7 CFR 3201.30 - Glass cleaners.  

Code of Federal Regulations, 2014 CFR

...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,...

2014-01-01

406

7 CFR 3201.30 - Glass cleaners.  

Code of Federal Regulations, 2013 CFR

...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,...

2013-01-01

407

ConcepTest: Glass-Rock Analogy  

NSDL National Science Digital Library

Glass is made by melting silica-rich sand. The molten glass is then formed into shapes as it cools. Glass making could be seen as an analog for the formation of a. igneous rock b. metamorphic rock c. sedimentary ...

408

Aspects of the mechanics of metallic glasses  

E-print Network

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, ...

Henann, David Lee

2011-01-01

409

Quinary metallic glass alloys  

DOEpatents

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.

Lin, X.; Johnson, W.L.

1998-04-07

410

Quinary metallic glass alloys  

DOEpatents

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.

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

1998-01-01

411

From Christmas Ornament to Glass Electrode  

NASA Astrophysics Data System (ADS)

In potentiometric techniques, pH measurements require a costly and fragile accessory: the glass electrode. A glass electrode is difficult to make because the wall of the sensing glass bulb must be very thin, and glass of special composition is required. Although the glass bulb may be made by a skilled glazier, we choose a more impressive and simple way. The glass bulb can be made from a Christmas-tree ornamental ball.

da Rocha, Rogério T.; Gutz, Ivano G. R.; Do Lago, Claudimir L.

1995-12-01

412

Space processing of chalcogenide glass  

NASA Technical Reports Server (NTRS)

A program was conducted to develop the technique of space processing for chalcogenide glass, and to define the process and equipment necessary. In the course of this program, successful long term levitation of objects in a 1-g environment was achieved. Glass beads 4 mm diameter were containerless melted and fused together.

Firestone, R. F.; Schramm, S. W.

1978-01-01

413

Refractory Glass Seals for SOFC  

SciTech Connect

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.

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

2011-07-01

414

A novel borophosphosilicate glass process  

Microsoft Academic Search

A novel low cost borophosphosilicate glass (BPSG) technology suitable for one micron processing is presented here. This technique allows glass to be flowed consistently and reproducibly at temperatures as low as 750°C. Flow angles are independent of device linewidths from 1 to 10 microns. The flow angle can be adjusted by changing the deposition time. The simplicity of the process

C. Y. Fu

1985-01-01

415

Method of determining glass durability  

DOEpatents

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.

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

1998-01-01

416

Method of determining glass durability  

DOEpatents

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.

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

1998-12-08

417

HEAT TRANSFER DURING GLASS FORMING  

Microsoft Academic Search

An important step in the optimization of a glass container production cycle is the determination of the glass temperature distribution during heat treatment. The ideal approach to this problem is to formulate a theoretical model for comparison against experimental data measured in a well-determined system. Discrepancies between theory and experiment may then give further direction for model improvement. This approach,

IHAB H. FARAG; MICHAEL J. BELIVEAU; RICHARD L. CURRAN

1987-01-01

418

SRNL POROUS WALL GLASS MICROSPHERES  

Microsoft Academic Search

The Savannah River National Laboratory (SRNL) has developed a new medium for storage of hydrogen and other gases. This involves fabrication of thin, Porous Walled, Hollow Glass Microspheres (PW-HGMs), with diameters generally in the range of 1 to several hundred microns. What is unique about the glass microballons is that porosity has been induced and controlled within the thin, one

G Wicks; L Leung Heung; R Ray Schumacher

2008-01-01

419

High level nuclear waste  

SciTech Connect

The DOE Division of Waste Products through a lead office at Savannah River is developing a program to immobilize all US high-level nuclear waste for terminal disposal. DOE high-level wastes include those at the Hanford Plant, the Idaho Chemical Processing Plant, and the Savannah River Plant. Commercial high-level wastes, for which DOE is also developing immobilization technology, include those at the Nuclear Fuel Services Plant and any future commercial fuels reprocessing plants. The first immobilization plant is to be the Defense Waste Processing Facility at Savannah River, scheduled for 1983 project submission to Congress and 1989 operation. Waste forms are still being selected for this plant. Borosilicate glass is currently the reference form, but alternate candidates include concretes, calcines, other glasses, ceramics, and matrix forms.

Crandall, J L

1980-01-01

420

Characterization of projected DWPF glasses heat treated to simulate canister centerline cooling  

SciTech Connect

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced and poured into stainless steel canisters in the Defense Waste Processing Facility (DWPF). Eventually these canistered waste forms will be sent to a geologic repository for final disposal. In order to assure acceptability by the repository, the Department of Energy has defined requirements which DWPF canistered waste forms must meet. These requirements are the Waste Acceptance Preliminary Specifications (WAPS). The WAPS require DWPF to identify the crystalline phases expected to be present in the final glass product. Knowledge of the thermal history of the borosilicate glass during filling and cooldown of the canister is necessary to determine the amount and type of crystalline phases present in the final glass product. Glass samples of seven projected DWPF compositions were cooled following the same temperature profile as that of glass at the centerline of the full-scale DWPF canister. The glasses were characterized by x-ray diffraction and scanning electron microscopy to identify the crystalline phases present The volume percents of each crystalline phase present were determined by quantitative x-ray diffraction. The Product Consistency Test (PCI) was used to determine the durability of the heat-treated glasses.

Marra, S.L.; Jantzen, C.M.

1992-05-01

421

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

422

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

SciTech Connect

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.

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

1993-01-01

423

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

SciTech Connect

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.

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

1993-05-01

424

Database and Interim Glass Property Models for Hanford HLW Glasses  

SciTech Connect

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.

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

2001-07-24

425

Product consistency testing of West Valley Compositional Variation Glasses  

SciTech Connect

Nuclear waste glass produced by the West Valley Demonstration Project (WVDP) must meet the requirements of the Waste Acceptance Preliminary Specification (WAPS) as developed by the US Department of Energy (DOE). To assist WVDP in complying with WAPS, the Materials Characterization Center (MCC) at Pacific Northwest Laboratory (PNL) used the Product Consistency Test (PCT) to evaluate 44 West Valley glasses that had previously been tested in FY 1987 and FY 1988. This report summarizes the results of the PCTs. The glasses tested, which were fabricated as sets of Compositional Variation Glasses for studies performed by the West Valley Support Task (WVST) at PNL during FY 1987 and FY 1988, were doped with Th and U and were variations of West Valley reference glasses. In addition, Approved Reference Material-1 (ARM-1) was used as a test standard (ARM-1 is supplied by the MCC). The PCT was originated at Westinghouse Savannah River Company (WSRC) by C. M. Jantzen and N. R. Bibler (Jantzen and Bibler 1989). The test is a seven-day modified MCC-3 test that uses crushed glass in the size range -100 +200 mesh with deionized water in a Teflon container. There is no agitation during the PCT, and no attempt to include CO{sub 2} from the test environment. Based on B and Li release, the glasses performed about the same as in previous modified MCC-3 testing performed in FY 1987 and FY 1988 (Reimus et al. 1988). The modified MCC-3 tests performed by Reimus et al. were similar to the PCT containers and the exclusion of CO{sub 2} from the tests.

Olson, K.M.; Marschman, S.C.; Piepel, G.F.; Whiting, G.K.

1994-11-01

426

Neptunium concentrations in solutions contacting actinide-doped glass  

SciTech Connect

To help predict concentrations of neptunium leached from nuclear waste repositories in geologic environments, the solubility of neptunium in a neptunium-doped borosilicate glass, which simulates a high-level waste glass, was investigated. The concentrations of neptunium in solutions contacting the crushed doped glass were found to be controlled by a neptunium solid phase that is similar to crystalline(c) NpO/sub 2/ in solubility. Thus, the maximum concentration of the neptunium leached from this waste form can be predicted from the solubility of NpO/sub 2/(c). This conclusion is based on similar neptunium concentrations in solutions contacting neptunium-doped glass, neptunium-doped glass plus NpO/sub 2/(c), and NpO/sub 2/(c) alone, under controlled redox potentials and a range of pH values. The quinhydrone used in this study was found to be a very effective redox buffer (the approximate pe + pH = 11.8). The predictions based on the thermodynamic data and the solvent extraction tests showed Np(V) to be the primary oxidation state in solution.

Rai, D.; McVay, G.L.; Strickert, R.G.

1982-07-01

427

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

SciTech Connect

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.

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

2011-03-28