Search NASA⌕ Search

SEARCH · Search NASA

Results for “BOROSILICATE GLASS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Electrospray Generated from the Tip-Sealed Fine Glass Capillary Inserted with an Acupuncture Needle Electrode

In electrospray, excess charges are supplied to a sample solution by the occurrence of electrochemical reactions. Recently, different versions of electrospray, e.g., dielectric barrier electrospray ionization, inductive desorption electrospray ionization, and electrostatic-ionization driven by dielectric polarization, have been reported in which the sample solution was not in direct contact with the metal electrode but separated by dielectric materials. The objective of the current work is to elucidate the mechanism of dielectric barrier electrospray. A sealed borosilicate glass capillary inserted with a fine acupuncture needle was used as a probe. A sample solution (~ 400 nL) was captured on the glass capillary tip and a positive high voltage (HV) pulse (+ 4.5 kV) was applied to the internal metal electrode. Mass spectra were measured as a function of the HV pulse width from μs to 10 s. Ions started to be detected with the pulse width of ~ 5 ms. The ion intensities increased slowly with time and reached a plateau in a few seconds. The charge distribution of cytochrome c [M + nH]{sup n+} shifted to higher n values from a few ms to seconds. In addition to cone-jet mode normal electrospray that lasted until all the liquid sample was depleted from the glass tip, the polarization-induced electrospray ionization was observed at the early stage of the HV application. .

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2012

Afterglow processes responsible for memory effect in nitrogen

The mechanisms responsible for memory effect in nitrogen at 6.6 mbars have been analysed based on experimental data of electrical breakdown time delay as a function of afterglow period. The analysis has shown that positive ions remaining from previous discharge, as well as metastable and highly vibrationally excited molecules, are responsible for memory effect in the early afterglow. These molecules lead to the formation of positive ions in mutual collisions in the afterglow. Positive ions initiate secondary electron emission from the cathode of a nitrogen-filled tube when voltage higher than static breakdown voltage is applied on the electrodes. On the other hand, N({sup 4}S) atoms have a large influence on memory effect in late afterglow. They recombine on the cathode surface forming metastable molecules, which release secondary electrons in collision with the cathode. The higher values of electrical breakdown time delay in the case of the tube with borosilicate glass walls than in the case of the tube with copper walls are a consequence of faster de-excitation of neutral active particles on the glass. Indirect confirmation of this assumption has been obtained when the tubes were irradiated with gamma radiation.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Fabrication and Properties of Advanced Ceramic Technetium Waste Forms - 17311

Technetium-99 (Tc, t{sub 1/2} = 2.13 x 10{sup 5} years) is a challenge from a nuclear waste perspective and is one of the most abundant, long-lived radioisotopes found in used nuclear fuel (UNF). Within the Hanford Tank Waste Treatment and Immobilization Plant, technetium volatilises at typical glass melting temperature, is captured in the off-gas treatment system and recycled back into the feed to eventually increase Tc-loadings of the glass. In this research we are providing a technical solution for continuously depleting the Tc-content of the glass melter feed by precipitating Tc from the off-gas effluents and effectively immobilizing {sup 99}Tc as durable ceramic waste form. We have developed a wet-chemical coprecipitation-based synthesis route to fabricate gram-size Tc-based pyrochlores with the model composition Sm{sub 2}(Tc{sub 0.5-x}Ru{sub x}Ti{sub 0.5}){sub 2}O{sub 7}. These ceramic Tc waste forms exhibit better technetium retention and corrosion resistance in ASTM C1220-10 based testing compared with technetium-containing LAWE4-type borosilicate glass, combined with optimal waste loading. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

World first in high level waste vitrification - A review of French vitrification industrial achievements

AREVA has more than 30 years experience in operating industrial HLW (High Level radioactive Waste) vitrification facilities (AVM - Marcoule Vitrification Facility, R7 and T7 facilities). This vitrification technology was based on borosilicate glasses and induction-heating. AVM was the world's first industrial HLW vitrification facility to operate in-line with a reprocessing plant. The glass formulation was adapted to commercial Light Water Reactor fission products solutions, including alkaline liquid waste concentrates as well as platinoid-rich clarification fines. The R7 and T7 facilities were designed on the basis of the industrial experience acquired in the AVM facility. The AVM vitrification process was implemented at a larger scale in order to operate the R7 and T7 facilities in-line with the UP2 and UP3 reprocessing plants. After more than 30 years of operation, outstanding record of operation has been established by the R7 and T7 facilities. The industrial startup of the CCIM (Cold Crucible Induction Melter) technology with enhanced glass formulation was possible thanks to the close cooperation between CEA and AREVA. CCIM is a water-cooled induction melter in which the glass frit and the waste are melted by direct high frequency induction. This technology allows the handling of highly corrosive solutions and high operating temperatures which permits new glass compositions and a higher glass production capacity. The CCIM technology has been implemented successfully at La Hague plant.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

A practical solution to Hanford's tank waste problem

The main characteristics of the Hanford radwaste are: -) it is extremely dilute and generates little heat, -) it is comprised of materials incompatible with high loading in borosilicate glass, and -) it is already situated at a good geological repository site. We propose that Hanford's radwaste should be homogenized (not separated), converted to an iron phosphate (Fe-P) glass 'aggregate' (marbles, gems, or cullet), that is then slurried up with a cementitious grout and pumped into Hanford's 'best preserved' tanks for disposal. This proposal is efficient, safe and cheap.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Control of the Reduction/Oxidation State of the High Level Waste Form in the Defense Waste Processing Facility at the Savannah River Site - 12451

The Defense Waste Processing Facility at the Savannah River Site treats and immobilizes High Level Waste into a durable borosilicate glass for safe, permanent storage. Among the parameters important to the overall process is the reduction/oxidation state of the glass. Control strategies for the reduction/oxidation state of the glass have been developed and evolved over the last 20 years to provide a current strategy which is both accurate and robust. A description of the methodologies implemented to control, evaluate, and validate the reduction/oxidation state of the glass is discussed along with the impact of future facility changes (made to pursue a more aggressive program to empty High Level Waste tanks at the Savannah River Site) on the reduction/oxidation state of glass. The reduction/oxidation state of the glass is an important parameter to the operation of the Defense Waste Processing Facility. Control, evaluation, and validation of the reduction/oxidation state of the glass is of particular importance for melter operation. Melter feed which is too oxidizing can negatively impact production, while feed which is too reducing can result in catastrophic failure of the melter. Control strategies for the reduction/oxidation state of the glass have been developed and evolved over the last 20 years to provide a current strategy which is both accurate and robust. (authors)

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

Aging studies on micro-fabricated alkali buffer-gas cells for miniature atomic clocks

We report an aging study on micro-fabricated alkali vapor cells using neon as a buffer gas. An experimental atomic clock setup is used to measure the cell's intrinsic frequency, by recording the clock frequency shift at different light intensities and extrapolating to zero intensity. We find a drift of the cell's intrinsic frequency of (−5.2 ± 0.6) × 10{sup −11}/day and quantify deterministic variations in sources of clock frequency shifts due to the major physical effects to identify the most probable cause of the drift. The measured drift is one order of magnitude stronger than the total frequency variations expected from clock parameter variations and corresponds to a slow reduction of buffer gas pressure inside the cell, which is compatible with the hypothesis of loss of Ne gas from the cell due to its permeation through the cell windows. A negative drift on the intrinsic cell frequency is reproducible for another cell of the same type. Based on the Ne permeation model and the measured cell frequency drift, we determine the permeation constant of Ne through borosilicate glass as (5.7 ± 0.7) × 10{sup −22} m{sup 2} s{sup −1 }Pa{sup −1} at 81 °C. We propose this method based on frequency metrology in an alkali vapor cell atomic clock setup based on coherent population trapping for measuring permeation constants of inert gases.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Progress in demonstrating the performance of Engineered Barriers for the disposal of HLW and SNF: lab studies and demonstration experiments - 20293

Disposal of high-level radioactive waste (HLW) and spent nuclear fuels (SNF) in a geological disposal facility requires a fundamental understanding of the degradation processes of materials used in its engineered barrier system (EBS) over very long timescales. Beyond the wasteform itself (i.e. the borosilicate glass for HLW or the fuel matrix and cladding for SNF), materials often employed in a disposal concept include metallic containers (typically copper and/or carbon steel) and clay-based buffer materials (typically bentonite). In this paper we explore key developments on the long-term evolution of materials employed for the immobilisation, isolation and containment of HLW and SNF in a geological disposal facility, including nuclear glasses, candidate container materials and clay buffers. Our discussion is based on the latest findings from both experimental studies and in-situ demonstration experiments. We present relevant findings from the long-term evolution of HLW glasses (UK composition), metallic materials for the containment system (envisaged in Switzerland, Sweden, Canada and other countries), and bentonite clays (envisaged in many national disposal programmes). (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Broadband Filtering of an X-Ray Spectrum by Transmission through a Polycapillary Structure

The efficiency of broadband filtering of a polychromatic X-ray spectrum by a polycapillary structure in the region of photon energies E > 10 keV was demonstrated. A polycapillary 40.5-mm-long rod made of borosilicate glass and containing 10{sup 6} parallel hexagonal capillaries was used as a filter. Filtering was performed by introducing a misalignment of 0–4 mrad between the axis of this capillary structure and the primary beam direction. The relative attenuation of spectral density observed at energies ranging from 12 to 23 keV was as high as 17 dB.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Single-step in-situ synthesis and optical properties of ZnSe nanostructured dielectric nanocomposites

This work provides the evidence of visible red photoluminescent light emission from ZnSe nanocrystals (NCs) grown within a dielectric (borosilicate glass) matrix synthesized by a single step in-situ technique for the first time and the NC sizes were controlled by varying only the concentration of ZnSe in glass matrix. The ZnSe NCs were investigated by UV-Vis optical absorption spectroscopy, Raman spectroscopy, and transmission electron microscopy (TEM). The sizes of the ZnSe NCs estimated from the TEM images are found to alter in the range of 2–53 nm. Their smaller sizes of the NCs were also calculated by using the optical absorption spectra and the effective mass approximation model. The band gap enlargements both for carrier and exciton confinements were evaluated and found to be changed in the range of 0–1.0 eV. The Raman spectroscopic studies showed blue shifted Raman peaks of ZnSe at 295 and 315 cm{sup −1} indicating phonon confinement effect as well as compressive stress effect on the surface atoms of the NCs. Red photoluminescence in ZnSe-glass nanocomposite reveals a broad multiple-peak structure due to overlapping of emission from NC size related electron-hole recombination (∼707 nm) and emissions from defects to traps, which were formed due to Se and Zn vacancies signifying potential application in photonics.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Deployment of Cesium Recovered from High Level Liquid Waste for Irradiation - Indian Scenario - 13128

Recovery of Cs-137 from HLW and its utilisation as source pencil in place of Co-60 is vital for medical and sewage treatment applications in India. For separation of Cs, specific ion exchange resins as well as 'Calyx crown' solvent have been developed and synthesized indigenously. A flow sheet involving separation of Cs from acidic HLW using Ammonium Molybdo Phosphate (AMP) resins, recovery of Cs from the loaded AMP column by dissolving it in alkali, ion exchange purification of Cs rich alkaline solution using Resorcinol-Formaldehyde Poly condensate (RF) resins and its elution in cesium nitrate form was developed and demonstrated. Solvent extraction route employing 0.03 Molar, 1-3-octyl oxy Calyx (4) arene crown-6 in 30% isodecyl alcohol and dodecane was also established using mixer settlers. Cesium lithium borosilicate glass based formulations have been considered as a glass matrix for Cs irradiation pencils. While choosing this vitreous matrix, attributes addressing maximum possible Cs-137 loading, low glass pouring temperature to minimise Cs volatility, reasonably good mechanical strength and good chemical durability have been considered. Recovered cesium nitrate solution was vitrified along with glass additives in an induction heated metallic melter and subsequently poured into 12 numbers of Cs irradiation pencils positioned on turn-table equipped with the load cell. The complete cycle involving recovery of Cs from HLW followed by its conversion into Cs pencil was demonstrated. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Corrosion Testing of Monofrax K-3 Refractory in Defense Waste Processing Facility (DWPF) Alternate Reductant Feeds

The Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) uses a combination of reductants and oxidants while converting high level waste (HLW) to a borosilicate waste form. A reducing flowsheet is maintained to retain radionuclides in their reduced oxidation states which promotes their incorporation into borosilicate glass. For the last 20 years of processing, the DWPF has used formic acid as the main reductant and nitric acid as the main oxidant. During reaction in the Chemical Process Cell (CPC), formate and formic acid release measurably significant H 2 gas which requires monitoring of certain vessel’s vapor spaces. A switch to a nitric acid-glycolic acid (NG) flowsheet from the nitric-formic (NF) flowsheet is desired as the NG flowsheet releases considerably less H 2 gas upon decomposition. This would greatly simplify DWPF processing from a safety standpoint as close monitoring of the H 2 gas concentration could become less critical. In terms of the waste glass melter vapor space flammability, the switch from the NF flowsheet to the NG flowsheet showed a reduction of H 2 gas production from the vitrification process as well. Due to the positive impact of the switch to glycolic acid determined on the flammability issues, evaluation of the other impacts of glycolic acid on the facility must be examined.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Effect of the inherent alkalis of alkali activated slag on the risk of alkali silica reaction

Alkali silica reaction (ASR) occurred in the alkali activated slag (AAS) concrete was evaluated by a revised mortar prism method. The mortars were made of blast furnace slags activated by alkali silicate solution possessing different modulus (0.5, 0.75, 1 and 2) as well as cations (sodium and potassium) and standard sand with a volume replacement of 25 vol% by borosilicate glass beads. Their changes in length and dynamic elastic modulus were monitored up to 7 months. The results showed that ASR has taken place among some mortars, which were evident under both light microscopy and electron microscopy with EDX analysis. The results also revealed that high alkali content did promote the risk of ASR but the degradation due to ASR was affected in a much more complex way.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Infrared and thermoelectric power generation in thin atomic layer deposited Nb-doped TiO{sub 2} films

Infrared radiation is used to radiatively transfer heat to a nanometric power generator (NPG) device with a thermoelectric Nb-doped TiO{sub 2} film deposited by atomic layer deposition (ALD) as the active element, onto a borosilicate glass substrate. The linear rise of the produced voltage with respect to the temperature difference between the “hot” and “cold” junctions, typical of the Seebeck effect, is missing. The discovery of the violation of the Seebeck effect in NPG devices combined with the ability of ALD to tune thermoelectric thin film properties could be exploited to increase the efficiency of these devices for energy harvesting purposes.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Closing the Book on the WVDP Vitrification Facility - 18222

Demolition of the West Valley Demonstration Project's Vitrification Facility was initiated on September 11, 2017, approximately 21 years after the facility produced its first canister of vitrified high-level waste. In the center of the structure, the heavily-reinforced concrete Vitrification Cell operated for six years, safely immobilizing about 24 million curies of high-level radioactive waste in borosilicate glass. When the facility was shut down in 2002, it had achieved the highest operational availability of any vitrification facility in the world. It was the first facility in the United States to complete its vitrification mission and is now the first in the nation to undergo demolition. This paper summarizes the selection, design, operation, deactivation and demolition of this facility. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

New insights into the role of fly ash in mitigating alkali-silica reaction (ASR) in concrete

Alkali-silica reaction (ASR) mitigation mechanisms of fly ash in concrete are still being debated and remain an interesting research topic. This study provides new insights into the role of aluminum oxide (Al{sub 2}O{sub 3}) in fly ash particles on ASR mitigation. A comprehensive test program was conducted and included expansion measurements, dissolution model experiments of exposed and embedded borosilicate glass elements, analyses of pore and immersion solutions, quantification of Ca(OH){sub 2} content, and microstructural analyses. It was found that in addition to the traditionally accepted mitigation mechanisms such as alkali binding, diffusion control and reduction in available Ca(OH){sub 2}, dissolution control of reactive aggregates by aluminum discharged from fly ash particles also contributed to the ASR mitigation. Re-introducing alkalis to fly ash-incorporated concrete prisms which exhibited undeleterious expansion under a long-term ASR exposure triggered and significantly increased the subsequent expansion.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Vitrification Process for Idaho HLW Calcine - 18433

The majority of the liquid wastes produced from reprocessing of several types of spent nuclear fuel at the Department of energy's (DOE) Idaho site have been volume reduced by calcination. The resulting ∼155,600 ft{sup 3} of calcined waste is stored in 43 shielded stainless steel bins, which have a 500-year design life. The calcined material is both a high-level waste and a RCRA hazardous waste, which complicates treatment and disposal options. In addition to a potential direct disposal option, treatment options that have been considered include steam reforming, hot isostatic pressing (HIP), and vitrification. This paper describes testing and evaluation of a vitrification option for the calcine. Vitrification to produce a borosilicate glass has the advantage that it is the only treatment that provides a waste form that meets the current HLW repository waste acceptance criteria. It is therefore the lowest risk option in terms of regulatory and legislative concerns. The present work addressed several key questions: (i) Calcine waste loadings in glass, which determine the number of HLW canisters produced and the required glass production rate (throughput) for the system design; (ii) Melt rate per unit glass pool surface area of the melter, which determines the sizing of the vitrification system; and (iii) The ability to meet waste form acceptance requirements (PCT and TCLP) while achieving reasonable waste loadings. These are issues of fundamental importance to the sizing estimates for the unit operations and overall flow-sheet and they, therefore, directly impact the cost and schedule estimates. Fully compliant, high-waste-loading glasses were developed for two of the four Idaho calcine wastes. The results demonstrate that waste loadings of 35 wt% waste oxides are achievable for the two alumina calcines and about 30 wt% is achievable for the two zirconia calcines. Testing of these formulations in a joule-heated ceramic melter showed glass production rates of over 5000 kg/(m2/d) for the Alumina calcine and over 8500 kg/(m{sup 2}/d) for the Zirconium-Na Blend calcine. These extremely high production rates translate directly into smaller system size and shorter mission duration and, therefore, reduced costs. Based on these results, a preliminary design for the full-scale vitrification system was developed. The system consists of waste receipt, vitrification, off-gas treatment, and canister sealing and decontamination equipment. The calcine is blended with the appropriate glass forming chemicals (or glass frit) and fed to the melter as a solid stream. The melter has a glass pool surface area of about 2.5 m{sup 2} and is equipped with a bubbling system to increase processing rates. Glass production rates of about 6 metric tons per day are projected. The vitrification system would be installed into the existing Idaho Waste Treatment Unit Facility (IWTU) so that no new facilities are required to house the treatment system, thus greatly reducing overall cost, duration, and risk. The system would be designed to treat all of the calcine waste within a period of 12 years at an operating efficiency of 80%, producing a total of about 8500 canisters each weighing two metric tons. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Biosynthesis of the palladium/sodium borosilicate nanocomposite using Euphorbia milii extract and evaluation of its catalytic activity in the reduction of chromium(VI), nitro compounds and organic dyes

Highlights: • Green synthesis of Pd/sodium borosilicate nanocomposite using Euphorbia milii aqueous extract. • Characterization of catalyst by FT-IR, XRD, FESEM, EDS, TEM and elemental mapping. • Catalytic reduction of Cr(VI), 2,4-DNPH, 4-NP, CR, MO and MB by Pd/sodium borosilicate nanocomposite. - Abstract: For the first time, a green method is developed to prepare palladium/sodium borosilicate nanocomposite by using aqueous extract of the leaves of Euphorbia milii as bioreducing and stabilizing agent. The immobilization of Pd NPs on the surface of the sodium borosilicate glass was established by several instrumental analysis including X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), EDS elemental dot maps and transmission electron microscopy (TEM). The green synthesized nanocatalyst exhibited excellent performance in the reduction of the chromium (VI) (Cr(VI)), nitro compounds such as 2,4-dinitrophenylhydrazine (2,4-DNPH) and 4-nitrophenol (4-NP) and some organic dyes containing Congo red (CR), Methyl orange (MO), and Methylene blue (MB). The biosynthesized heterogeneous catalyst was easily recovered and reused at least in 5 consecutive reactions with no losing of its performance.

77 NANOSCIENCE AND NANOTECHNOLOGY↗