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Sample records for metal fuel swelling

  1. Gas-bubble growth mechanisms in the analysis of metal fuel swelling

    SciTech Connect

    Gruber, E.E.; Kramer, J.M.

    1986-06-01

    During steady-state irradiation, swelling rates associated with growth of fission-gas bubbles in metallic fast reactor fuels may be expected to remain small. As a consequence, bubble-growth mechanisms are not a major consideration in modeling the steady-state fuel behavior, and it is usually adequate to consider the gas pressure to be in equilibrium with the external pressure and surface tension restraint. On transient time scales, however, various bubble-growth mechanisms become important components of the swelling rate. These mechanisms include growth by diffusion, for bubbles within grains and on grain boundaries; dislocation nucleation at the bubble surface, or ''punchout''; and bubble growth by creep. Analyses of these mechanisms are presented and applied to provide information on the conditions and the relative time scales for which the various processes should dominate fuel swelling. The results are compared to a series of experiments in which the swelling of irradiated metal fuel was determined after annealing at various temperatures and pressures. The diffusive growth of bubbles on grain boundaries is concluded to be dominant in these experiments.

  2. Swelling-resistant nuclear fuel

    DOEpatents

    Arsenlis, Athanasios; Satcher, Jr., Joe; Kucheyev, Sergei O.

    2011-12-27

    A nuclear fuel according to one embodiment includes an assembly of nuclear fuel particles; and continuous open channels defined between at least some of the nuclear fuel particles, wherein the channels are characterized as allowing fission gasses produced in an interior of the assembly to escape from the interior of the assembly to an exterior thereof without causing significant swelling of the assembly. Additional embodiments, including methods, are also presented.

  3. Fission induced swelling of U-Mo/Al dispersion fuel

    NASA Astrophysics Data System (ADS)

    Kim, Yeon Soo; Jeong, G. Y.; Park, J. M.; Robinson, A. B.

    2015-10-01

    Fission-induced swelling of U-Mo/Al dispersion fuel meat was measured using microscopy images obtained from post-irradiation examination. The data of reduced-size plate-type test samples and rod-type test samples were employed for this work. A model to predict the meat swelling of U-Mo/Al dispersion fuel was developed. This model is composed of several submodels including a model for interaction layer (IL) growth between U-Mo and Al matrix, a model for IL thickness to IL volume conversion, a correlation for the fission-induced swelling of U-Mo alloy particles, a correlation for the fission-induced swelling of IL, and models of U-Mo and Al consumption by IL growth. The model was validated using full-size plate data that were not included in the model development.

  4. Swelling

    MedlinePlus

    ... syndrome Poor nutrition Pregnancy Thyroid disease Too little albumin in the blood (hypoalbuminemia) Too much salt or ... the swelling. Tests that may be done include: Albumin blood test Blood electrolyte levels Echocardiography ECG Kidney ...

  5. The swelling of nitrile rubber by selected species in a synthetic jet turbine fuel

    NASA Astrophysics Data System (ADS)

    Graham, John Lynn

    The swelling of nitrile O-ring seals in petroleum distillate fuels has long been attributed to the aromatic species in these fuels. This presents a problem for synthetic fuels as they typically do not contain these aromatic species and thus may cause O-ring seals to shrink and fail. The composition of petroleum distillate fuels is extremely complex and it is not clear whether the swelling property originates from the aromatics in general, or if certain aromatics contribute more swelling character than others. Consequently, developing a general description of an efficient swelling promoter for O-rings in liquid hydrocarbon fuels will allow an unambiguous selection of candidate swelling agents for synthetic fuels. To accomplish this, a study was undertaken of the swelling of nitrile rubber (the most widely used O-ring material) in JP-5 (the jet propulsion fuel used by the U.S. Navy) and its synthetic equivalent S-5. Briefly, examining the molecular structure of nitrile rubber showed the fuel resistance of this polymer resides in the polar character of the cyano group suggesting that polar species in general, and hydrogen-bonded species in particular, should serve as efficient swelling promoters. A thorough test program utilizing a unique optical dilatometry method to provide temporal volume swell data, a GC-MS method for measuring the polymer/fuel partitioning, and a spectroscopic examination of thin nitrile rubber films confirmed this hypothesis. This program also showed that swelling character increases with decreasing molar volume which is consistent with previous work and general theories of solubility. Overall, this study showed that the most efficient aromatic swelling promoters for nitrile rubber are naphthalenes and asymmetrically substituted alkyl benzenes. However, polar species such as ketones and alcohols can be more efficient than aromatics while phenols and aromatic alcohols represent the most efficient potential swelling promoters for nitrile rubber in

  6. Fission induced swelling and creep of U–Mo alloy fuel

    SciTech Connect

    Yeon Soo Kim; G. L. Hofman; J. S. Cheon; A. B. Robinson; D. M. Wachs

    2013-06-01

    Tapering of U–Mo alloy fuel at the end of plates is attributed to lateral mass transfer by fission induced creep, by which fuel mass is relocated away from the fuel end region where fission product induced fuel swelling is in fact the highest. This mechanism permits U–Mo fuel to achieve high burnup by effectively relieving stresses at the fuel end region, where peak stresses are otherwise expected because peak fission product induced fuel swelling occurs there. ABAQUS FEA was employed to examine whether the observed phenomenon can be simulated using physical–mechanical data available in the literature. The simulation results obtained for several plates with different fuel fabrication and loading scheme showed that the measured data were able to be simulated with a reasonable creep rate coefficient. The obtained creep rate constant lies between values for pure uranium and MOX, and is greater than all other ceramic uranium fuels.

  7. Theoretical analysis of swelling characteristics of cylindrical uranium dioxide fuel pins with a niobium - 1-percent-zirconium clad

    NASA Technical Reports Server (NTRS)

    Saltsman, J. F.

    1973-01-01

    The relations between clad creep strain and fuel volume swelling are shown for cylindrical UO2 fuel pins with a Nb-1Zr clad. These relations were obtained by using the computer code CYGRO-2. These clad-strain - fuel-volume-swelling relations may be used with any fuel-volume-swelling model, provided the fuel volume swelling is isotropic and independent of the clad restraints. The effects of clad temperature (over a range from 118 to 1642 K (2010 to 2960 R)), pin diameter, clad thickness and central hole size in the fuel have been investigated. In all calculations the irradiation time was 500 hours. The burnup rate was varied.

  8. PLUTONIUM METALLIC FUELS FOR FAST REACTORS

    SciTech Connect

    STAN, MARIUS; HECKER, SIEGFRIED S.

    2007-02-07

    Early interest in metallic plutonium fuels for fast reactors led to much research on plutonium alloy systems including binary solid solutions with the addition of aluminum, gallium, or zirconium and low-melting eutectic alloys with iron and nickel or cobalt. There was also interest in ternaries of these elements with plutonium and cerium. The solid solution and eutectic alloys have most unusual properties, including negative thermal expansion in some solid-solution alloys and the highest viscosity known for liquid metals in the Pu-Fe system. Although metallic fuels have many potential advantages over ceramic fuels, the early attempts were unsuccessful because these fuels suffered from high swelling rates during burn up and high smearing densities. The liquid metal fuels experienced excessive corrosion. Subsequent work on higher-melting U-PuZr metallic fuels was much more promising. In light of the recent rebirth of interest in fast reactors, we review some of the key properties of the early fuels and discuss the challenges presented by the ternary alloys.

  9. Swelling and creep observed in AISI 304 fuel pin cladding from three MOX fuel assemblies irradiated in EBR-II

    NASA Astrophysics Data System (ADS)

    Garner, F. A.; Makenas, B. J.; Chastain, S. A.

    2011-06-01

    Three 37-pin MOX-fueled experimental subassemblies were irradiated in EBR-II with fuel pin cladding constructed from annealed AISI 304 stainless steel. Analysis of the swelling and irradiation creep of the cladding showed that the terminal swelling rate of AISI 304 stainless steel appears to be ˜1%/dpa and that swelling is very reproducible for identical irradiation conditions. The swelling at a given neutron fluence is rather sensitive to both irradiation temperature and especially to the neutron flux, however, with the primary influence residing in the transient regime. As the neutron flux increases the duration of the transient regime is increased in agreement with other recent studies. The duration of the transient regime is also decreased by increasing irradiation temperature. In these assemblies swelling reached high levels rather quickly, reducing the opportunity for fuel pin cladding interaction and thereby reducing the contribution of irradiation creep to the total deformation. It also appears that in this swelling-before-creep scenario that the well-known "creep disappearance" phenomenon was operating strongly.

  10. Stress-enhanced swelling of metal during irradiation

    SciTech Connect

    Garner, F.A.; Gilbert, E.R.; Porter, D.L.

    1980-04-01

    Data are available which show that stress plays a major role in the development of radiation-induced void growth in AISI 316 and many other alloys. Earlier experiments came to the opposite conclusion and are shown to have investigated stress levels which inadvertantly cold-worked the material. Stress-affected swelling spans the entire temperature range in fast reactor irradiations and accelerates with increasing irradiatin temperature. It also appears to operate in all alloy starting conditions investigated. Two major microstructural mechanisms appear to be causing the enhancement of swelling, which for tensile stresses is manifested primarily as a decrease in the incubation period. These mechanisms are stress-induced changes in the interstitial capture efficiency of voids and stress-induced changes in the vacancy emission rate of various microstructural components. There also appears to be an enhancement of intermetallic phase formation with applied stress and this is shown to increase swelling by accelerating the microchemical evolution that precedes void growth at high temperature. This latter consideration complicates the extrapolation of these data to compressive stress states.

  11. Screening of Potential O-Ring Swelling Additives for Ultraclean Transportation Fuels

    SciTech Connect

    Baltrus, J.P.; Link, D.D.; Zandhuis, P.H.; Gormley, R.J.; Anderson, R.R.

    2007-03-01

    Several classes of organic compounds and mixtures of organic compounds were evaluated as potential additives to Fischer-Tropsch fuels to promote swelling of nitrile rubber o-rings that come in contact with the fuels. Computational modeling studies were also carried out to predict which compounds might be best at promoting o-ring swelling. The combined experimental-theoretical approach showed that steric factors strongly influence the interactions between additives and the nitrile sites in the rubber that result in swelling. Select compounds incorporating both oxygenate and aromatic functionalities appear to be the best candidates for additives because of a "dual" interaction between complementary functionalities on these compounds and the nitrile rubber.

  12. Model for incorporating fuel swelling and clad shrinkage effects in diffusion theory calculations (LWBR Development Program)

    SciTech Connect

    Schick, W.C. Jr.; Milani, S.; Duncombe, E.

    1980-03-01

    A model has been devised for incorporating into the thermal feedback procedure of the PDQ few-group diffusion theory computer program the explicit calculation of depletion and temperature dependent fuel-rod shrinkage and swelling at each mesh point. The model determines the effect on reactivity of the change in hydrogen concentration caused by the variation in coolant channel area as the rods contract and expand. The calculation of fuel temperature, and hence of Doppler-broadened cross sections, is improved by correcting the heat transfer coefficient of the fuel-clad gap for the effects of clad creep, fuel densification and swelling, and release of fission-product gases into the gap. An approximate calculation of clad stress is also included in the model.

  13. Effects of potential additives to promote seal swelling on the thermal stability of synthetic jet fuels

    SciTech Connect

    Lind, D.D.; Gormley, R.G.; Zandhuis, P.H.; Baltrus, J.P.

    2007-10-01

    Synthetic fuels derived from the Fischer-Tropsch (F-T) process using natural gas or coal-derived synthesis gas as feedstocks can be used for powering of ground vehicles, aircraft and ships. Because of their chemical and physical properties, F-T fuels will probably require additives in order to meet specifications with respect to lubricity and seal swell capability for use in ground and air vehicles. These additives can include oxygenates and compounds containing other heteroatoms that may adversely affect thermal stability. In order to understand what additives will be the most beneficial, a comprehensive experimental and computational study of conventional and additized fuels has been undertaken. The experimental approach includes analysis of the trace oxygenate and nitrogen-containing compounds present in conventional petroleum-derived fuels and trying to relate their presence (or absence) to changes in the desired properties of the fuels. This paper describes the results of efforts to test the thermal stability of synthetic fuels and surrogate fuels containing single-component additives that have been identified in earlier research as the best potential additives for promoting seal swelling in synthetic fuels, as well as mixtures of synthetic and petroleum-derived fuels.

  14. Potential Additives to Promote Seal Swell in Synthetic Fuels and Their Effect on Thermal Stability

    SciTech Connect

    Link, Dirk D.; Gormley, Robert J.; Baltrus, John P.; Anderson, Richard R.; Zandhuis, Paul H.

    2008-03-01

    Synthetic, fuels derived from the Fischer-Tropsch (F-T) process using natural gas or coal-derived synthesis gas as feedstocks can be used for powering ground vehicles, aircraft, and ships. Because of their chemical and physical properties, F-T fuels will probably require additives in order to meet specifications with respect to lubricity and seal swell capability for use in ground and air vehicles. Using both experimental and computational studies, the propensity of certain species to enhance the seal swell characteristics of synthetic fuels and surrogates has been determined, and promising additives have been identified. Important structural characteristics for potential additives, namely an aromatic ring along with a polar constituent, are described. The thermal stability of synthetic and surrogate fuels containing the single-component additive benzyl alcohol, which is representative of this structural class, has been determined by batch stressing of the mixtures at 350º C for up to 12 h. Synthetic fuels spiked with benzyl alcohol at concentrations (vol%) of 1.0, 0.75, and 0.5 have demonstrated the ability to swell nitrile rubber o-rings to a comparable degree as petroleum jet fuel. Further, batch reactor studies have shown that addition of benzyl alcohol does not degrade the thermal oxidative stability of the fuel based on gravimetric analysis of the solid deposits after stressing. GC-MS was used to characterize the products from thermal stressing of neat and additized surrogate jet fuel, and their compositions were compared with respect to the creation of certain species and their potential effect on deposition.

  15. Potential Additives to Promote Seal Swell in Synthetic Fuels and Their Effect on Thermal Stability

    SciTech Connect

    Link, D.D.; Gormley, R.J.; Baltrus, J.P.; Anderson, R.R.; Zandhuis, P.H.

    2008-03-01

    Synthetic fuels derived from the Fischer–Tropsch (F-T) process using natural gas or coal-derived synthesis gas as feedstocks can be used for powering ground vehicles, aircraft, and ships. Because of their chemical and physical properties, F-T fuels will probably require additives in order to meet specifications with respect to lubricity and seal swell capability for use in ground and air vehicles. Using both experimental and computational studies, the propensity of certain species to enhance the seal swell characteristics of synthetic fuels and surrogates has been determined, and promising additives have been identified. Important structural characteristics for potential additives, namely an aromatic ring along with a polar constituent, are described. The thermal stability of synthetic and surrogate fuels containing the single-component additive benzyl alcohol, which is representative of this structural class, has been determined by batch stressing of the mixtures at 350 °C for up to 12 h. Synthetic fuels spiked with benzyl alcohol at concentrations (vol %) of 1.0, 0.75, and 0.5 have demonstrated the ability to swell nitrile rubber o-rings to a comparable degree as petroleum jet fuel. Further, batch reactor studies have shown that addition of benzyl alcohol does not degrade the thermal oxidative stability of the fuel based on gravimetric analysis of the solid deposits after stressing. GC-MS was used to characterize the products from thermal stressing of neat and additized surrogate jet fuel, and their compositions were compared with respect to the creation of certain species and their potential effect on deposition.

  16. A new swelling model and its application to uranium silicide research reactor fuel

    SciTech Connect

    Hofman, G.L.; Rest, J.; Snelgrove, J.L.

    1992-01-01

    This document discusses a new version of the dispersion fuel behavior model currently being incorporated in DART, which has been generated. The model's description of fuel swelling - more specifically, the evaluation of fission-gas bubble morphology - is significantly improved. Although some of the assumptions underlying the basic model are derived from systems other than U[sub 3]Si[sub 2], it represents a physically realistic interpretation of the observed irradiation behavior of U[sub 3]Si[sub 2] over a wide range of fission densities and fission rates.

  17. A new swelling model and its application to uranium silicide research reactor fuel

    SciTech Connect

    Hofman, G.L.; Rest, J.; Snelgrove, J.L.

    1992-12-31

    This document discusses a new version of the dispersion fuel behavior model currently being incorporated in DART, which has been generated. The model`s description of fuel swelling - more specifically, the evaluation of fission-gas bubble morphology - is significantly improved. Although some of the assumptions underlying the basic model are derived from systems other than U{sub 3}Si{sub 2}, it represents a physically realistic interpretation of the observed irradiation behavior of U{sub 3}Si{sub 2} over a wide range of fission densities and fission rates.

  18. Effect of grain morphology on gas bubble swelling in UMo fuels - A 3D microstructure dependent Booth model

    NASA Astrophysics Data System (ADS)

    Hu, Shenyang; Burkes, Douglas; Lavender, Curt A.; Joshi, Vineet

    2016-11-01

    A three dimensional microstructure dependent swelling model is developed for studying the fission gas swelling kinetics in irradiated nuclear fuels. The model is extended from the Booth model [1] in order to investigate the effect of heterogeneous microstructures on gas bubble swelling kinetics. As an application of the model, the effect of grain morphology, fission gas diffusivity, and spatially dependent fission rate on swelling kinetics are simulated in UMo fuels. It is found that the decrease of grain size, the increase of grain aspect ratio for the grain having the same volume, and the increase of fission gas diffusivity (fission rate) cause the increase of swelling kinetics. Other heterogeneities such as second phases and spatially dependent thermodynamic properties including diffusivity of fission gas, sink and source strength of defects could be naturally integrated into the model to enhance the model capability.

  19. Swelling behavior detection of irradiated U-10Zr alloy fuel using indirect neutron radiography

    NASA Astrophysics Data System (ADS)

    Sun, Yong; Huo, He-yong; Wu, Yang; Li, Jiangbo; Zhou, Wei; Guo, Hai-bing; Li, Hang; Cao, Chao; Yin, Wei; Wang, Sheng; Liu, Bin; Feng, Qi-jie; Tang, Bin

    2016-11-01

    It is hopeful that fusion-fission hybrid energy system will become an effective approach to achieve long-term sustainable development of fission energy. U-10Zr alloy (which means the mass ratio of Zr is 10%) fuel is the key material of subcritical blanket for fusion-fission hybrid energy system which the irradiation performance need to be considered. Indirect neutron radiography is used to detect the irradiated U-10Zr alloy because of the high residual dose in this paper. Different burnup samples (0.1%, 0.3%, 0.5% and 0.7%) have been tested with a special indirect neutron radiography device at CMRR (China Mianyang Research Reactor). The resolution of the device is better than 50 μm and the quantitative analysis of swelling behaviors was carried out. The results show that the swelling behaviors relate well to burnup character which can be detected accurately by indirect neutron radiography.

  20. Evaluation of Metal-Fueled Surface Reactor Concepts

    SciTech Connect

    Poston, David I.; Marcille, Thomas F.; Kapernick, Richard J.; Hiatt, Matthew T.; Amiri, Benjamin W.

    2007-01-30

    Surface fission power systems for use on the Moon and Mars may provide the first use of near-term reactor technology in space. Most near-term surface reactor concepts specify reactor temperatures <1000 K to allow the use of established material and power conversion technology and minimize the impact of the in-situ environment. Metal alloy fuels (e.g. U-10Zr and U-10Mo) have not traditionally been considered for space reactors because of high-temperature requirements, but they might be an attractive option for these lower temperature surface power missions. In addition to temperature limitations, metal fuels are also known to swell significantly at rather low fuel burnups ({approx}1 a/o), but near-term surface missions can mitigate this concern as well, because power and lifetime requirements generally keep fuel burnups <1 a/o. If temperature and swelling issues are not a concern, then a surface reactor concept may be able to benefit from the high uranium density and relative ease of manufacture of metal fuels. This paper investigates two reactor concepts that utilize metal fuels. It is found that these concepts compare very well to concepts that utilize other fuels (UN, UO2, UZrH) on a mass basis, while also providing the potential to simplify material safeguards issues.

  1. Hybrid combustion with metallized fuels

    NASA Technical Reports Server (NTRS)

    Yi, Jianwen; Wygle, Brian S.; Bates, Ronald W.; Jones, Michael D.; Ramohalli, Kumar

    1993-01-01

    A chemical method of adding certain catalysts to improve the degradation process of a solid fuel is discussed. Thermogravimetric (TGA) analysis used to study the fundamental degradation behavior of a typical hybrid fuel (HTPB) shows that high surface temperatures increase the degradation rate. Fuels were tested in a laboratory-scale experimental hybrid rocket and their behavior was compared to a baseline behavior of HTPB fuel regression rates. It was found that a small amount of metal powder added to the fuel can significantly increase the regression rates.

  2. Metal Matrix Microencapsulated (M3) fuel neutronics performance in PWRs

    SciTech Connect

    Fratoni, Massimiliano; Terrani, Kurt A

    2012-01-01

    Metal Matrix Microencapsulated (M3) fuel consists of TRISO or BISO coated fuel particles directly dispersed in a matrix of zirconium metal to form a solid rod (Fig. 1). In this integral fuel concept the cladding tube and the failure mechanisms associated with it have been eliminated. In this manner pellet-clad-interactions (PCI), thin tube failure due to oxidation and hydriding, and tube pressurization and burst will be absent. M3 fuel, given the high stiffness of the integral rod design, could as well improve grid-to-rod wear behavior. Overall M3 fuel, compared to existing fuel designs, is expected to provide greatly improved operational performance. Multiple barriers to fission product release (ceramic coating layers in the coated fuel particle and te metal matrix) and the high thermal conductivity zirconium alloy metal matrix contribute to the enhancement in fuel behavior. The discontinuous nature of fissile material encapsulated in coated particles provides additional assistance; for instance if the M3 fuel rod is snapped into multiple pieces, only the limited number of fuel particles at the failure cross section are susceptible to release fission products. This is in contrast to the conventional oxide fuel where the presence of a small opening in the cladding provides the pathway for release of the entire inventory of fission products from the fuel rod. While conventional metal fuels (e.g. U-Zr and U-Mo) are typically expected to experience large swelling under irradiation due to the high degree of damage from fission fragments and introduction of fission gas into the lattice, this is not the case for M3 fuels. The fissile portion of the fuel is contained within the coated particle where enough room is available to accommodate fission gases and kernel swelling. The zirconium metal matrix will not be exposed to fission products and its swelling is known to be very limited when exposed solely to neutrons. Under design basis RIA and LOCA, fuel performance will be

  3. Unrestrained swelling of uranium-nitride fuel irradiated at temperatures ranging from 1100 to 1400 K (1980 to 2520 R)

    NASA Technical Reports Server (NTRS)

    Rohal, R. G.; Tambling, T. N.

    1973-01-01

    Six fuel pins were assembled, encapsulated, and irradiated in the Plum Brook Reactor. The fuel pins employed uranium mononitride (UN) in a stainless steel (type 304L) clad. The pins were irradiated for approximately 4000 hours to burnups of about 2.0 atom percent uranium. The average clad surface temperature during irradiation was about 1100 K (1980 deg R). Since stainless steel has a very low creep strength relative to that of UN at this temperature, these tests simulated unrestrained swelling of UN. The tests indicated that at 1 percent uranium atom burnup the unrestrained diametrical swelling of UN is about 0.5, 0.8, and 1.0 percent at 1223, 1264, and 1306 K (2200, deg 2273 deg, and 2350 deg R), respectively. The tests also indicated that the irradiation induced swelling of unrestrained UN fuel pellets appears to be isotropic.

  4. Fuel swelling and interaction layer formation in the SELENIUM Si and ZrN coated U(Mo) dispersion fuel plates irradiated at high power in BR2

    NASA Astrophysics Data System (ADS)

    Leenaers, A.; Van den Berghe, S.; Koonen, E.; Kuzminov, V.; Detavernier, C.

    2015-03-01

    In the framework of the SELENIUM project two full size flat fuel plates were produced with respectively Si and ZrN coated U(Mo) particles and irradiated in the BR2 reactor at SCK•CEN. Non-destructive analysis of the plates showed that the fuel swelling profiles of both SELENIUM plates were very similar to each other and none of the plates showed signs of pillowing or excessive swelling at the end of irradiation at the highest power position (local maximum 70% 235U). The microstructural analysis showed that the Si coated fuel has less interaction phase formation at low burn-up but at the highest burn-ups, defects start to develop on the IL-matrix interface. The ZrN coated fuel, shows a virtual absence of reaction between the U(Mo) and the Al, up to high fission densities after which the interaction layer formation starts and defects develop in the matrix near the U(Mo) particles. It was found and is confirmed by the SELENIUM (Surface Engineering of Low ENrIched Uranium-Molybdenum) experiment that there are two phenomena at play that need to be controlled: the formation of an interaction layer and swelling of the fuel. As the interaction layer formation occurs at the U(Mo)-matrix interface, applying a diffusion barrier (coating) at that interface should prevent the interaction between U(Mo) and the matrix. The U(Mo) swelling, observed to proceed at an accelerating rate with respect to fission density accumulation, is governed by linear solid state swelling and fission gas bubble swelling due to recrystallization of the fuel. The examination of the SELENIUM fuel plates clearly show that for the U(Mo) dispersion fuel to be qualified, the swelling rate at high burn-up needs to be reduced.

  5. Novel reactive elastomer-metal oxide composite: Effect of filler size and content on swelling and reinforcement

    NASA Astrophysics Data System (ADS)

    Han, Dingzhi; Yue, Chee Yoon; Qu, Meng; Robisson, Agathe

    2014-05-01

    A novel elastomer-metal oxide composite that swells and stiffens upon hydration will be presented. Conventional water-swellable elastomers filled with hydrogels absorb water and swell upon hydration but their modulus decreases as a result of fluid water diluting the rubber matrix. Reduced stiffness compromise the reliability of swellable elastomers used in sealing applications. One major application of swellable elastomers is fluid containment seals for zonal isolation in the oilfield. For effective sealing, the contact pressure between the seal and the surrounding wall should be high while deformation should be limited when a differential pressure is applied. Both conditions can be achieved by means of swelling and stiffening of the seal; hence, the new reactive elastomer-metal oxide composite is developed such that after it is exposed to water, the composite swells and stiffens simultaneously. Composites filled with different amounts of oxide were studied and it was observed that swelling up to almost 100% with an increase in modulus of about 200% could be achieved for the best performing compound. Composites filled with different sizes of the metal oxide were also studied. The finest filler was found to impart the greatest modulus, both before and after hydration, to the composite although swelling was slightly reduced compared with the larger particles. Another advantage of the composite for sealing purposes is that the swelling is largely retained even after complete removal of the solvent; i.e., drying.

  6. EXPERIMENTAL LIQUID METAL FUEL REACTOR

    DOEpatents

    Happell, J.J.; Thomas, G.R.; Denise, R.P.; Bunts, J.L. Jr.

    1962-01-23

    A liquid metal fuel nuclear fission reactor is designed in which the fissionable material is dissolved or suspended in a liquid metal moderator and coolant. The liquid suspension flows into a chamber in which a critical amount of fissionable material is obtained. The fluid leaves the chamber and the heat of fission is extracted for power or other utilization. The improvement is in the support arrangement for a segrnented graphite core to permit dif ferential thermal expansion, effective sealing between main and blanket liquid metal flows, and avoidance of excessive stress development in the graphite segments. (AEC)

  7. Status of Transuranic Bearing Metallic Fuel Development

    SciTech Connect

    Steve Hayes; Bruce Hilton; Heather MacLean; Debbie Utterbeck; Jon Carmack; Kemal Pasamehmetoglu

    2009-09-01

    This paper summarizes the status of the metallic fuel development under the Advanced Fuel Cycle Initiative (AFCI). The metallic fuel development program includes fuel fabrication, characterization, advanced cladding research, irradiation testing and post-irradiation examination (PIE). The focus of this paper is on the recent irradiation experiments conducted in the Advanced Test Reactor and some PIE results from these tests.

  8. Metal-gas fuel cell

    SciTech Connect

    Struthers, R.C.

    1984-10-16

    A metal-gas fuel cell comprising an anode chamber filled with a base anolyte solution, a metallic anode plate immersed in the anolyte; an ion exchange chamber filled with a base ionolyte solution adjacent the anode chamber; a cationic membrane between the anode and ion exchange chambers separating the anolyte and ionolyte; a cathode plate adjacent the ion exchange chamber remote from the cationic membrane with one surface in contact with the ionolyte and another surface in contact with a cathode fuel gas. The cathode plate is a laminated structure including a layer of hydrophyllic material in contact with the ionolyte, a layer of gas permeable hydrophobic material in contact with the gas and a gas and liquid permeable current collector of inert material with catalytic surfaces within the layer of hydrophyllic material. The anode and cathode plates are connected with an external electric circuit which effects the flow of electrons from the anode plate to the cathode plate.

  9. Mechanical behaviors of the dispersion nuclear fuel plates induced by fuel particle swelling and thermal effect II: Effects of variations of the fuel particle diameters

    NASA Astrophysics Data System (ADS)

    Ding, Shurong; Wang, Qiming; Huo, Yongzhong

    2010-02-01

    In order to predict the irradiation mechanical behaviors of plate-type dispersion nuclear fuel elements, the total burnup is divided into two stages: the initial stage and the increasing stage. At the initial stage, the thermal effects induced by the high temperature differences between the operation temperatures and the room temperature are mainly considered; and at the increasing stage, the intense mechanical interactions between the fuel particles and the matrix due to the irradiation swelling of fuel particles are focused on. The large-deformation thermo-elasto-plasticity finite element analysis is performed to evaluate the effects of particle diameters on the in-pile mechanical behaviors of fuel elements. The research results indicate that: (1) the maximum Mises stresses and equivalent plastic strains at the matrix increase with the fuel particle diameters; the effects of particle diameters on the maximum first principal stresses vary with burnup, and the considered case with the largest particle diameter holds the maximum values all along; (2) at the cladding near the interface between the fuel meat and the cladding, the Mises stresses and the first principal stresses undergo major changes with increasing burnup, and different variations exist for different particle diameter cases; (3) the maximum Mises stresses at the fuel particles rise with the particle diameters.

  10. Dimensional errors in LIGA-produced metal structures due to thermal expansion and swelling of PMMA.

    SciTech Connect

    Kistler, Bruce L.; Dryden, Andrew S.; Crowell, Jeffrey A.W.; Griffiths, Stewart K.

    2004-04-01

    Numerical methods are used to examine dimensional errors in metal structures microfabricated by the LIGA process. These errors result from elastic displacements of the PMMA mold during electrodeposition and arise from thermal expansion of the PMMA when electroforming is performed at elevated temperatures and from PMMA swelling due to absorption of water from aqueous electrolytes. Both numerical solutions and simple analytical approximations describing PMMA displacements for idealized linear and axisymmetric geometries are presented and discussed. We find that such displacements result in tapered metal structures having sidewall slopes up to 14 {micro}m per millimeter of height for linear structures bounded by large areas of PMMA. Tapers for curved structures are of similar magnitude, but these structures are additionally skewed from the vertical. Potential remedies for reducing dimensional errors are also discussed. Here we find that auxiliary moat-like features patterned into the PMMA surrounding mold cavities can reduce taper by an order of magnitude or more. Such moats dramatically reduce tapers for all structures, but increase skew for curved structures when the radius of curvature is comparable to the structure height.

  11. Joint swelling

    MedlinePlus

    Swelling of a joint ... Joint swelling may occur along with joint pain . The swelling may cause the joint to appear larger or abnormally shaped. Joint swelling can cause pain or stiffness. After an ...

  12. Mechanical behaviors of the dispersion nuclear fuel plates induced by fuel particle swelling and thermal effect I: Effects of variations of the fuel particle volume fractions

    NASA Astrophysics Data System (ADS)

    Wang, Qiming; Yan, Xiaoqing; Ding, Shurong; Huo, Yongzhong

    2010-05-01

    A new method of modeling the in-pile mechanical behaviors of dispersion nuclear fuel elements is proposed. Considering the irradiation swelling together with the thermal effect, numerical simulations of the in-pile mechanical behaviors are performed with the developed finite element models for different fuel particle volume fractions of the fuel meat. The effects of the particle volume fractions on the mechanical performances of the fuel element are studied. The research results indicate that: (1) the maximum Mises stresses and equivalent plastic strains at the matrix increase with the particle volume fractions at each burnup; the locations of the maximum first principal stresses shift with increasing burnup; at low burnups, the maximum first principal stresses increase with the particle volume fractions; while at high burnups, the 20% volume fraction case holds the lowest value; (2) at the cladding, the maximum equivalent plastic strains and the tensile principal stresses increase with the particle volume fractions; while the maximum Mises stresses do not follow this order at high burnups; (3) the maximum Mises stresses at the fuel particles increase with the particle volume fractions, and the particles will engender plastic strains until the particle volume fraction reaches high enough.

  13. Using graphitic foam as the bonding material in metal fuel pins for sodium fast reactors

    NASA Astrophysics Data System (ADS)

    Karahan, Aydın; Kazimi, Mujid S.

    2013-10-01

    The study evaluates the possible use of graphite foam as the bonding material between U-Pu-Zr metallic fuel and steel clad for sodium fast reactor applications using FEAST-METAL fuel performance code. Furthermore, the applicability of FEAST-METAL to the advanced fuel designs is demonstrated. Replacing the sodium bond with a chemically stable foam material would eliminate fuel clad metallurgical interactions, and allow for fuel swelling under low external stress. Hence, a significant improvement is expected for the steady state and transient performance. FEAST-METAL was used to assess the thermo-mechanical behavior of the new fuel form and a reference metallic fuel pin. Nearly unity conversion ratio, 75% smear density U-15Pu-6Zr metallic fuel pin with sodium bond, and T91 cladding was selected as a reference case. It was found that operating the reference case at high clad temperatures (600-660 °C) results in (1) excessive clad wastage formation/clad thinning due to lanthanide migration and formation of brittle phases at clad inner surface, and (2) excessive clad hoop strain at the upper axial section due mainly to the occurrence of thermal creep. The combination of these two factors may lead to cladding breach. The work concludes that replacing the sodium bond with 80% porous graphite foam and reducing the fuel smear density to 70%, it is likely that the fuel clad metallurgical interaction would be eliminated while the fuel swelling is allowed without excessive fuel clad mechanical interaction. The suggested design appears as an alternative for a high performance metallic fuel design for sodium fast reactors.

  14. Gellan gum-g-N-vinyl-2-pyrrolidone: synthesis, swelling, metal ion uptake and flocculation behavior.

    PubMed

    Verma, Shiv Kumar; Pandey, Vijay Shankar; Behari, Mithilesh Yadav Kunj

    2015-01-01

    The synthesis of graft copolymer (gellan gum-g-N-vinyl-2-pyrrolidone) is carried out in nitrogen atmosphere using potassium bromate and silver as redox system. The reaction conditions for maximum grafting have been optimized by varying the reaction variables, including the concentration of N-vinyl-2-pyrrolidone (12.0 × 10(--2) to 28 × 10(--2) mol dm(-3)), potassium bromate (6 × 10(-3) to 22 × 10(-3) mol dm(-3)), silver (2.4 × 10(-3)to 5.6 × 10(-3) mol dm(-3)), sulphuric acid (2.0 × 10(-3) to 10 × 10(-3) mol dm(-3)), gellan gum (0.6-1.4 g dm(-3)) along with time duration (60 to 180 min) and temperature (30-50 °C).Water swelling capacity, metal ion sorption and flocculation studies of synthesized graft copolymer have been performed with respect to the parent polymer. The graft copolymer has been characterized by FTIR spectroscopy and thermogravimetric analysis.

  15. Metal hydride fuel storage and method thereof

    SciTech Connect

    Morse, Jeffrey D.; Jankowski, Alan F.; Yu, Conrad

    2006-10-17

    Disclosed herein is a metal hydride fuel storage cartridge having integrated resistive heaters that can be used in conjunction with fuel cells such as MEMS-based fuel cells. The cartridge is fabricated using micromachining methods and thin/thick film materials synthesis techniques.

  16. Metal hydride fuel storage and method thereof

    DOEpatents

    Morse, Jeffrey D [Martinez, CA; Jankowski, Alan F [Livermore, CA; Yu, Conrad [Antioch, CA

    2009-05-05

    Disclosed herein is a metal hydride fuel storage cartridge having integrated resistive heaters that can be used in conjunction with fuel cells such as MEMS-based fuel cells. The cartridge is fabricated using micromachining methods and thin/thick film materials synthesis techniques.

  17. Investigation of the irradiation-swelling mechanisms in refractory metals at high temperatures. Final scientific report, 1 March 1985-31 July 1988

    SciTech Connect

    Bajaj, R.; Hall, B.O.; Fenske, G.R.; Greggi, J.C.; Taylor, A.T.

    1989-06-01

    This report presents the results of an investigation of elevated-temperature irradiation swelling in refractory metals with an objective of understanding swelling mechanisms in these materials and demonstrating practicality of swelling-resistant materials. The study was divided into three phases. During the first phase, a theoretical model was developed for the swelling in body-centered cubic (bcc) metals. The model was based on chemical reaction rate formalism. Calculations were carried out on on a model material, niobium, which was selected for the study. Experimental and theoretical work was conducted to determine the swelling mechanism. Niobium was irradiated with Nb(++) ions to a dose of 50 dpa and swelling was determined by transmission electron microscopy. A peak swelling at 900C of 7% was observed. No swelling was observed above 1300C. The experimental data were compared to those predicted by the theoretical model. Reasonable agreements were obtained between the experimental and theoretical swelling curve when niobium-oxygen interaction was included. Sink-strength ratios were also calculated from the data. The theoretical model was extended during the second phase to include loop growth/shrinkage in bcc metals. During the third phase of the program, two alloys, Nb-5Hf and Nb-5W, were irradiated with Nb(++) alone and with Nb(++) + He(+) over a temperature range of 800 - 1350C. (AW)

  18. Fuel pin

    DOEpatents

    Christiansen, D.W.; Karnesky, R.A.; Leggett, R.D.; Baker, R.B.

    1987-11-24

    A fuel pin for a liquid metal nuclear reactor is provided. The fuel pin includes a generally cylindrical cladding member with metallic fuel material disposed therein. At least a portion of the fuel material extends radially outwardly to the inner diameter of the cladding member to promote efficient transfer of heat to the reactor coolant system. The fuel material defines at least one void space therein to facilitate swelling of the fuel material during fission.

  19. 33 CFR 183.538 - Metallic fuel line materials.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Metallic fuel line materials. 183... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.538 Metallic fuel line materials. Each metallic fuel line connecting the fuel tank with the fuel inlet connection...

  20. Modification of chitosan by swelling and crosslinking using epichlorohydrin as heavy metal Cr (VI) adsorbent in batik industry wastes

    NASA Astrophysics Data System (ADS)

    Hastuti, B.; Masykur, A.; Hadi, S.

    2016-02-01

    Study on chitosan modification by swelling and crosslinking and its application as a selective adsorbent for heavy metals Cr (VI) in batik industry wastes was done. Swelling is intended to improve chitosan porosity, whereas crosslinking is to increase the resistance of chitosan against acid. Natural samples are generally acidic, thus limiting chitosan application as an adsorbent. Modification of chitosan by combining swelling and crosslinking is expected to increase its adsorption capacity in binding heavy metal ions in water. The modified chitosan was later contacted with Cr (VI) to test its adsorption capacity with a variation of pH and contact time. Finally, application of modified chitosan was done in batik industry waste containing Cr (IV). Based on the results, chitosan-ECH 25% (v/v) was the optimum concentration of crosslinker to adsorb Cr (VI) ions. Modified chitosan has a solubility resistance to acids, even though a strong acid. Modification of chitosan also improved its adsorption capacity to Cr (VI) from 74% (pure chitosan) to 89% with contact time 30 min at pH 3. On the application to the batik wastes, the modified chitosan were able to adsorb Cr (IV) up to the level of 5 ppm. Thus, the modified chitosan has a potential to be applied to as an adsorbent of Cr (VI) in batik industry wastes.

  1. Swelling of U-7Mo/Al-Si dispersion fuel plates under irradiation - Non-destructive analysis of the AFIP-1 fuel plates

    NASA Astrophysics Data System (ADS)

    Wachs, D. M.; Robinson, A. B.; Rice, F. J.; Kraft, N. C.; Taylor, S. C.; Lillo, M.; Woolstenhulme, N.; Roth, G. A.

    2016-08-01

    Extensive fuel-matrix interactions leading to plate pillowing have proven to be a significant impediment to the development of a suitable high density low-enriched uranium molybdenum alloy (U-Mo) based dispersion fuel for high power applications in research reactors. The addition of silicon to the aluminum matrix was previously demonstrated to reduce interaction layer growth in mini-plate experiments. The AFIP-1 project involved the irradiation, in-canal examination, and post-irradiation examination of two fuel plates. The irradiation of two distinct full size, flat fuel plates (one using an Al-2wt%Si matrix and the other an Al-4043 (∼4.8 wt% Si) matrix) was performed in the INL ATR reactor in 2008-2009. The irradiation conditions were: ∼250 W/cm2 peak Beginning Of Life (BOL) power, with a ∼3.5e21 f/cm3 peak burnup. The plates were successfully irradiated and did not show any pillowing at the end of the irradiation. This paper reports the results and interpretation of the in-canal and post-irradiation non-destructive examinations that were performed on these fuel plates. It further compares additional PIE results obtained on fuel plates irradiated in contemporary campaigns in order to allow a complete comparison with all results obtained under similar conditions. Except for a brief indication of accelerated swelling early in the irradiation of the Al-2Si plate, the fuel swelling is shown to evolve linearly with the fission density through the maximum burnup.

  2. Preparing oxidizer coated metal fuel particles

    NASA Technical Reports Server (NTRS)

    Shafer, J. I.; Simmons, G. M. (Inventor)

    1974-01-01

    A solid propellant composition of improved efficiency is described which includes an oxidizer containing ammonium perchlorate, and a powered metal fuel, preferably aluminum or beryllium, in the form of a composite. The metal fuel is contained in the crystalline lattice framework of the oxidizer, as well as within the oxidizer particles, and is disposed in the interstices between the oxidizer particles of the composition. The propellant composition is produced by a process comprising the crystallization of ammonium perchlorate in water, in the presence of finely divided aluminum or beryllium. A suitable binder is incorporated in the propellant composition to bind the individual particles of metal with the particles of oxidizer containing occluded metal.

  3. Microstructural Characterization of Cast Metallic Transmutation Fuels

    SciTech Connect

    J. I. Cole; D. D. Keiser; J. R. Kennedy

    2007-09-01

    As part of the Global Nuclear Energy Partnership (GNEP) and the Advanced Fuel Cycle Initiative (AFCI), the US Department of Energy (DOE) is participating in an international collaboration to irradiate prototypic actinide-bearing transmutation fuels in the French Phenix fast reactor (FUTURIX-FTA experiment). The INL has contributed to this experiment by fabricating and characterizing two compositions of metallic fuel; a non-fertile 48Pu-12Am-40Zr fuel and a low-fertile 35U-29Pu-4Am-2Np-30Zr fuel for insertion into the reactor. This paper highlights results of the microstructural analysis of these cast fuels, which were reasonably homogeneous in nature, but had several distinct phase constituents. Spatial variations in composition appeared to be more pronounced in the low-fertile fuel when compared to the non-fertile fuel.

  4. Recent irradiation tests of uranium-plutonium-zirconium metal fuel elements

    SciTech Connect

    Pahl, R.G.; Lahm, C.E.; Villarreal, R.; Hofman, G.L.; Beck, W.N.

    1986-09-01

    Uranium-Plutonium-Zirconium metal fuel irradiation tests to support the ANL Integral Fast Reactor concept are discussed. Satisfactory performance has been demonstrated to 2.9 at.% peak burnup in three alloys having 0, 8, and 19 wt % plutonium. Fuel swelling measurements at low burnup in alloys to 26 wt % plutonium show that fuel deformation is primarily radial in direction. Increasing the plutonium content in the fuel diminishes the rate of fuel-cladding gap closure and axial fuel column growth. Chemical redistribution occurs by 2.1 at.% peak burnup and generally involves the inward migration of zirconium and outward migration of uranium. Fission gas release to the plenum ranges from 46% to 56% in the alloys irradiated to 2.9 at.% peak burnup. No evidence of deleterious fuel-cladding chemical or mechanical interaction was observed.

  5. 33 CFR 183.562 - Metallic fuel lines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Metallic fuel lines. 183.562... fuel lines. (a) Each metallic fuel line that is mounted to the boat structure must be connected to the engine by a flexible fuel line. (b) Each metallic fuel line must be attached to the boat's...

  6. Performance of low smeared density sodium-cooled fast reactor metal fuel

    DOE PAGES

    Porter, D. L.; H. J. M. Chichester; Medvedev, P. G.; Hayes, S. L.; Teague, M. C.

    2015-06-17

    An experiment was performed in the Experimental Breeder Rector-II (EBR-II) in the 1990s to show that metallic fast reactor fuel could be used in reactors with a single, once-through core. To prove the long duration, high burnup, high neutron exposure capability an experiment where the fuel pin was designed with a very large fission gas plenum and very low fuel smeared density (SD). The experiment, X496, operated to only 8.3 at. % burnup because the EBR-II reactor was scheduled for shut-down at that time. Many of the examinations of the fuel pins only funded recently with the resurgence of reactormore » designs using very high-burnup fuel. The results showed that, despite the low smeared density of 59% the fuel swelled radially to contact the cladding, fission gas release appeared to be slightly higher than demonstrated in conventional 75%SD fuel tests and axial growth was about the same as 75% SD fuel. There were axial positions in some of the fuel pins which showed evidence of fuel restructuring and an absence of fission products with low metaling points and gaseous precursors (Cs and Rb). Lastly, a model to investigate whether these areas may have overheated due to a loss of bond sodium indicates that it is a possible explanation for the fuel restructuring and something to be considered for fuel performance modeling of low SD fuel.« less

  7. Performance of low smeared density sodium-cooled fast reactor metal fuel

    SciTech Connect

    Porter, D. L.; H. J. M. Chichester; Medvedev, P. G.; Hayes, S. L.; Teague, M. C.

    2015-06-17

    An experiment was performed in the Experimental Breeder Rector-II (EBR-II) in the 1990s to show that metallic fast reactor fuel could be used in reactors with a single, once-through core. To prove the long duration, high burnup, high neutron exposure capability an experiment where the fuel pin was designed with a very large fission gas plenum and very low fuel smeared density (SD). The experiment, X496, operated to only 8.3 at. % burnup because the EBR-II reactor was scheduled for shut-down at that time. Many of the examinations of the fuel pins only funded recently with the resurgence of reactor designs using very high-burnup fuel. The results showed that, despite the low smeared density of 59% the fuel swelled radially to contact the cladding, fission gas release appeared to be slightly higher than demonstrated in conventional 75%SD fuel tests and axial growth was about the same as 75% SD fuel. There were axial positions in some of the fuel pins which showed evidence of fuel restructuring and an absence of fission products with low metaling points and gaseous precursors (Cs and Rb). Lastly, a model to investigate whether these areas may have overheated due to a loss of bond sodium indicates that it is a possible explanation for the fuel restructuring and something to be considered for fuel performance modeling of low SD fuel.

  8. Hydrogel-swelling driven delivery device for corrosion resistance of metal in water.

    PubMed

    Gu, Yu; Yang, Li-Ming; Chen, Jie; Wang, Ling-Ling; Chen, Bin

    2015-01-01

    Corrosion on steel and copper pipes in industry can trigger pollution and weakness due to undesired chemical and biochemical reactions. Too much or too little inhibitor can decrease its efficiency, even causing waste and pollution. In this contribution, an innovative delivery device driven by hydrogel swelling, mainly consisting of a semi-permeable membrane, a hydrogel-swelling force drive and a release orifice, was developed to control the release of inhibitor in a water system at a constant rate, leading the amount of inhibitor to maintain a proper concentration. The effects of hydrogel mass and orifice dimension on release property were studied for controlling release rate. Moreover, a weight loss experiment on carbon steels was carried out to show the incredible anti-corrosion function of the system.

  9. Hydrogel-swelling driven delivery device for corrosion resistance of metal in water.

    PubMed

    Gu, Yu; Yang, Li-Ming; Chen, Jie; Wang, Ling-Ling; Chen, Bin

    2015-01-01

    Corrosion on steel and copper pipes in industry can trigger pollution and weakness due to undesired chemical and biochemical reactions. Too much or too little inhibitor can decrease its efficiency, even causing waste and pollution. In this contribution, an innovative delivery device driven by hydrogel swelling, mainly consisting of a semi-permeable membrane, a hydrogel-swelling force drive and a release orifice, was developed to control the release of inhibitor in a water system at a constant rate, leading the amount of inhibitor to maintain a proper concentration. The effects of hydrogel mass and orifice dimension on release property were studied for controlling release rate. Moreover, a weight loss experiment on carbon steels was carried out to show the incredible anti-corrosion function of the system. PMID:26676016

  10. 33 CFR 183.538 - Metallic fuel line materials.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Metallic fuel line materials. 183... fuel line materials. Each metallic fuel line connecting the fuel tank with the fuel inlet connection on...) Except for corrugated flexible fuel line, have a minimum wall thickness of 0.029 inches....

  11. Microexplosive Metallized Fuels for Energetic Materials

    NASA Astrophysics Data System (ADS)

    Terry, Brandon; Rubio, Mario; Gunduz, Ibrahim; Son, Steven

    2015-06-01

    Microexplosions have been widely investigated for multicomponent liquid fuels. This phenomenon is caused by internal bubble nucleation and growth from within a fuel droplet (i.e., intraparticle boiling), which induces droplet fragmentation. Microexplosive fuels are advantageous as they promote fuel atomization, which can reduce residence times, increase completeness of combustion, and reduce product agglomeration (if condensed phase products are formed). While this is well understood and utilized with liquid fuels, it has not been fully investigated for metallic fuel particles. Recent work has shown that mechanical activation of aluminum/polymer (inclusion) composites can also cause microexplosions, analogous to liquid emulsion fuels. Gases are produced when the polymer within the composite decomposes below the boiling point of aluminum, causing the composite particle to shatter into smaller particles. Here we show that fully metallic multicomponent fuels (e.g., Al-Li alloy) can also microexplode during combustion and compare this to inclusion composite ignition. Because the two components have a large disparity in boiling points, intraparticle boiling causes the particle to expand and eventually shatter the fuel particle, analogous to missive liquid fuels. National Defense Science and Engineering Graduate Fellowship, 32 CFR 168a; AFOSR MURI, Contract #FA9550-13-1-0004.

  12. Extending FEAST-METAL for analysis of low content minor actinide bearing and zirconium rich metallic fuels for sodium fast reactors

    NASA Astrophysics Data System (ADS)

    Karahan, Aydın

    2011-07-01

    Computational models in FEAST-METAL fuel behaviour code have been upgraded to simulate minor actinide bearing zirconium rich metallic fuels for use in sodium fast reactors. Increasing the zirconium content to 20-40 wt.% causes significant changes in fuel slug microstructure affecting thermal, mechanical, chemical, and fission gas behaviour. Inclusion of zirconium rich phase reduces the fission gas swelling rate significantly in early irradiation. Above the threshold fission gas swelling, formation of micro-cracks, and open pores increase material compliancy enhance diffusivity, leading to rapid fuel gas swelling, interconnected porosity development and release of the fission gases and helium. Production and release of helium was modelled empirically as a function of americium content and fission gas production, consistent with previous Idaho National Laboratory studies. Predicted fuel constituent redistribution is much smaller compared to typical U-Pu-10Zr fuel operated at EBR-II. Material properties such as fuel thermal conductivity, modulus of elasticity, and thermal expansion coefficient have been approximated using the available database. Creep rate and fission gas diffusivity of high zirconium fuel is lowered by an order of magnitude with respect to the reference low zirconium fuel based on limited database and in order to match experimental observations. The new code is benchmarked against the AFC-1F fuel assembly post irradiation examination results. Satisfactory match was obtained for fission gas release and swelling behaviour. Finally, the study considers a comparison of fuel behaviour between high zirconium content minor actinide bearing fuel and typical U-15Pu-6Zr fuel pins with 75% smear density. The new fuel has much higher fissile content, allowing for operating at lower neutron flux level compared to fuel with lower fissile density. This feature allows the designer to reach a much higher burnup before reaching the cladding dose limit. On the other

  13. Volatile species retention during metallic fuel casting

    NASA Astrophysics Data System (ADS)

    Fielding, Randall S.; Porter, Douglas L.

    2013-10-01

    Metallic nuclear fuels are candidate transmutation fuel forms for advanced fuel cycles. Through the operation of the Experimental Breeder Reactor II metallic nuclear fuels have been shown to be robust and easily manufactured. However, concerns have been raised concerning loss of americium during the casting process because of its high vapor pressure. In order to address these concerns a gaseous diffusion model was developed and a series of experiments using both manganese and samarium as surrogates for americium were conducted. The modeling results showed that volatility losses can be controlled to essentially no losses with a modest overpressure. Experimental results also showed volatile species retention down to no detectable losses through overpressure, and although the loss values varied from the model results the same trend was seen. Based on these results it is very probable that americium losses through volatility can be controlled to no detectable losses through application of a modest overpressure during casting.

  14. Volatile Species Retention During Metallic Fuel Casting

    SciTech Connect

    Randall S. Fielding; Douglas L. Proter

    2013-10-01

    Metallic nuclear fuels are candidate transmutation fuel forms for advanced fuel cycles. Through the operation of the Experimental Breeder Reactor II metallic nuclear fuels have been shown to be robust and easily manufactured. However, concerns have been raised concerning loss of americium during the casting process because of its high vapor pressure. In order to address these concerns a gaseous diffusion model was developed and a series of experiments using both manganese and samarium as surrogates for americium were conducted. The modeling results showed that volatility losses can be controlled to essentially no losses with a modest overpressure. Experimental results also showed volatile species retention down to no detectable losses through overpressure, although the loss values varied from the model results the same trend was seen. Bases on these results it is very probably that americium losses through volatility can be controlled to no detectable losses through application of a modest overpressure during casting.

  15. Metal containing polymers as fuel cell catalysts

    NASA Astrophysics Data System (ADS)

    Reed, James L.

    1987-06-01

    Several aspects of the fuel cell problem were addressed in this investigation. The objective of this work was the development of a fuel cell electrode-catalyst for use in a carbon monoxide fuel cell, which would utilize polymer bound metal complexes as the catalytic species. Several commercially available polymers were examined to be used as backbones in the development of an electrode-catalyst. Polystyrene was chosen for more extensive study. The polymer was activated by complete or partial monochloromethylation of the pendant phenyls. Several schemes for binding cyclic tetradentate and bidentate ligands to the activated polymers were not obtained. The transition metals cobalt and nickel were incorporated into the polymers, and these new materials were examined. In addition, the electrochemical behavior of several metal complexes which hold potential as catalytic species was examined.

  16. Performance of low smeared density sodium-cooled fast reactor metal fuel

    NASA Astrophysics Data System (ADS)

    Porter, D. L.; Chichester, H. J. M.; Medvedev, P. G.; Hayes, S. L.; Teague, M. C.

    2015-10-01

    An experiment was performed in the Experimental Breeder Rector-II (EBR-II) in the 1990s to show that metallic fast reactor fuel could be used in reactors with a single, once-through core. To prove the long duration, high burnup, high neutron exposure capability an experiment where the fuel pin was designed with a very large fission gas plenum and very low fuel smeared density (SD). The experiment, X496, operated to only 8.3 at.% burnup because the EBR-II reactor was scheduled for shut-down at that time. Many of the examinations of the fuel pins only funded recently with the resurgence of reactor designs using very high-burnup fuel. The results showed that, despite the low smeared density of 59% the fuel swelled radially to contact the cladding, fission gas release appeared to be slightly higher than demonstrated in conventional 75%SD fuel tests and axial growth was about the same as 75% SD fuel. There were axial positions in some of the fuel pins which showed evidence of fuel restructuring and an absence of fission products with low melting points and gaseous precursors (Cs and Rb). A model to investigate whether these areas may have overheated due to a loss of bond sodium indicates that it is a possible explanation for the fuel restructuring and something to be considered for fuel performance modeling of low SD fuel.

  17. Electrolytic recovery of reactor metal fuel

    DOEpatents

    Miller, W.E.; Tomczuk, Z.

    1994-09-20

    A new electrolytic process and apparatus are provided using sodium, cerium or a similar metal in alloy or within a sodium beta or beta[double prime]-alumina sodium ion conductor to electrolytically displace each of the spent fuel metals except for cesium and strontium on a selective basis from the electrolyte to an inert metal cathode. Each of the metals can be deposited separately. An electrolytic transfer of spent fuel into the electrolyte includes a sodium or cerium salt in the electrolyte with sodium or cerium alloy being deposited on the cathode during the transfer of the metals from the spent fuel. The cathode with the deposit of sodium or cerium alloy is then shunted to an anode and the reverse transfer is carried out on a selective basis with each metal being deposited separately at the cathode. The result is that the sodium or cerium needed for the process is regenerated in the first step and no additional source of these reactants is required. 2 figs.

  18. Electrolytic recovery of reactor metal fuel

    DOEpatents

    Miller, William E.; Tomczuk, Zygmunt

    1994-01-01

    A new electrolytic process and apparatus are provided using sodium, cerium or a similar metal in alloy or within a sodium beta or beta"-alumina sodium ion conductor to electrolytically displace each of the spent fuel metals except for cesium and strontium on a selective basis from the electrolyte to an inert metal cathode. Each of the metals can be deposited separately. An electrolytic transfer of spent fuel into the electrolyte includes a sodium or cerium salt in the electrolyte with sodium or cerium alloy being deposited on the cathode during the transfer of the metals from the spent fuel. The cathode with the deposit of sodium or cerium alloy is then chanted to an anode and the reverse transfer is carried out on a selective basis with each metal being deposited separately at the cathode. The result is that the sodium or cerium needed for the process is regenerated in the first step and no additional source of these reactants is required.

  19. Electrolytic recovery of reactor metal fuel

    DOEpatents

    Miller, W.E.; Tomczuk, Z.

    1993-02-03

    This invention is comprised of a new electrolytic process and apparatus using sodium, cerium or a similar metal in an alloy or within a sodium beta or beta-alumina sodium ion conductor to electrolytically displace each of the spent fuel metals except for Cesium and strontium on a selective basis from the electrolyte to an inert metal cathode. Each of the metals can be deposited separately. An electrolytic transfer of spent fuel into the electrolyte includes a sodium or cerium salt in the electrolyte with sodium or cerium alloy being deposited on the cathode during the transfer of the metals from the spent fuel. The cathode with the deposit of sodium or cerium alloy is then changed to an anode and the reverse transfer is carried out on a selective basis with each metal being deposited separately at the cathode. The result is that the sodium or cerium needed for the process is regenerated in the first step and no additional source of these reactants is required.

  20. Modeling of Gap Closure in Uranium-Zirconium Alloy Metal Fuel - A Test Problem

    SciTech Connect

    Simunovic, Srdjan; Ott, Larry J; Gorti, Sarma B; Nukala, Phani K; Radhakrishnan, Balasubramaniam; Turner, John A

    2009-10-01

    Uranium based binary and ternary alloy fuel is a possible candidate for advanced fast spectrum reactors with long refueling intervals and reduced liner heat rating [1]. An important metal fuel issue that can impact the fuel performance is the fuel-cladding gap closure, and fuel axial growth. The dimensional change in the fuel during irradiation is due to a superposition of the thermal expansion of the fuel due to heating, volumetric changes due to possible phase transformations that occur during heating and the swelling due to fission gas retention. The volumetric changes due to phase transformation depend both on the thermodynamics of the alloy system and the kinetics of phase change reactions that occur at the operating temperature. The nucleation and growth of fission gas bubbles that contributes to fuel swelling is also influenced by the local fuel chemistry and the microstructure. Once the fuel expands and contacts the clad, expansion in the radial direction is constrained by the clad, and the overall deformation of the fuel clad assembly depends upon the dynamics of the contact problem. The neutronics portion of the problem is also inherently coupled with microstructural evolution in terms of constituent redistribution and phase transformation. Because of the complex nature of the problem, a series of test problems have been defined with increasing complexity with the objective of capturing the fuel-clad interaction in complex fuels subjected to a wide range of irradiation and temperature conditions. The abstract, if short, is inserted here before the introduction section. If the abstract is long, it should be inserted with the front material and page numbered as such, then this page would begin with the introduction section.

  1. Advanced Recycling Core Accommodating Oxide Fuel and Metal Fuel for Closed Fuel Cycle

    NASA Astrophysics Data System (ADS)

    Ikeda, Kazumi; Maddox, James W.; Nakazato, Wataru; Kunishima, Shigeru

    This report presents a unique TRU burning core capable of accommodating oxide fuel and metal fuel and easy to change oxide core to metal core conforming to the design requirements. For the homogeneous oxide fueled core containing transuranics (TRU) fuel with 12% of the moderator pins, the results of calculation show the TRU conversion ratio (ratio of loss of TRU to loss of heavy metal) of 0.33 and the TRU burning capability (ratio of loss of TRU per electric generation) of 67 kg/TWeh. On the other hand, the calculations replacing from oxide fuel assemblies to metal fuel assemblies have indicated the TRU transmutation capability of 69 kg/TWeh with the TRU conversion ratio of 0.30. As the result of simulation calculations, three ordinary fuel exchanges transform the oxide equilibrium core to the full metal core by way of transitional cores, where the maximum linear heat rates are still equal to the metal equilibrium core or less. With this, the presented core concept is concluded that a full oxide core, a full metal core, mixed fueled cores can be materialized in the presented first unit of Advanced Recycling Reactor (ARR1).

  2. Fuel cells and the theory of metals.

    NASA Technical Reports Server (NTRS)

    Bocciarelli, C. V.

    1972-01-01

    Metal theory is used to study the role of metal catalysts in electrocatalysis, with particular reference to alkaline hydrogen-oxygen fuel cells. Use is made of a simple model, analogous to that used to interpret field emission in vacuum. Theoretical values for all the quantities in the Tafel equation are obtained in terms of bulk properties of the metal catalysts (such as free electron densities and Fermi level). The reasons why some processes are reversible (H-electrodes) and some irreversible (O-electrodes) are identified. Selection rules for desirable properties of catalytic materials are established.

  3. Dependence of the rate of steady-state swelling of fuel-element claddings made of ChS68 steel on the characteristics of neutron irradiation

    NASA Astrophysics Data System (ADS)

    Kozlov, A. V.; Portnykh, I. A.

    2016-08-01

    Rate of steady-state swelling of fuel-element sheaths made of the 06Kh16N15M2G2TFR steel in the course of their operation in a BN-600 reactor has been calculated. In the calculations, the diffusion characteristics of point defects and the results of the determination of the characteristics of the irradiation-induced porosity have been used. The dependence of the dose rate of steady-state swelling on neutron-irradiation characteristics has been analyzed. It has been established that the dose rate of swelling at the steady-state stage is independent of the energy of migration of vacancies and the rate of generation of atomic displacements.

  4. 33 CFR 183.562 - Metallic fuel lines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... engine by a flexible fuel line. (b) Each metallic fuel line must be attached to the boat's structure... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Metallic fuel lines. 183.562...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Manufacturer Requirements § 183.562...

  5. A new code for predicting the thermo-mechanical and irradiation behavior of metallic fuels in sodium fast reactors

    NASA Astrophysics Data System (ADS)

    Karahan, Aydın; Buongiorno, Jacopo

    2010-01-01

    An engineering code to predict the irradiation behavior of U-Zr and U-Pu-Zr metallic alloy fuel pins and UO2-PuO2 mixed oxide fuel pins in sodium-cooled fast reactors was developed. The code was named Fuel Engineering and Structural analysis Tool (FEAST). FEAST has several modules working in coupled form with an explicit numerical algorithm. These modules describe fission gas release and fuel swelling, fuel chemistry and restructuring, temperature distribution, fuel-clad chemical interaction, and fuel and clad mechanical analysis including transient creep-fracture for the clad. Given the fuel pin geometry, composition and irradiation history, FEAST can analyze fuel and clad thermo-mechanical behavior at both steady-state and design-basis (non-disruptive) transient scenarios. FEAST was written in FORTRAN-90 and has a simple input file similar to that of the LWR fuel code FRAPCON. The metal-fuel version is called FEAST-METAL, and is described in this paper. The oxide-fuel version, FEAST-OXIDE is described in a companion paper. With respect to the old Argonne National Laboratory code LIFE-METAL and other same-generation codes, FEAST-METAL emphasizes more mechanistic, less empirical models, whenever available. Specifically, fission gas release and swelling are modeled with the GRSIS algorithm, which is based on detailed tracking of fission gas bubbles within the metal fuel. Migration of the fuel constituents is modeled by means of thermo-transport theory. Fuel-clad chemical interaction models based on precipitation kinetics were developed for steady-state operation and transients. Finally, a transient intergranular creep-fracture model for the clad, which tracks the nucleation and growth of the cavities at the grain boundaries, was developed for and implemented in the code. Reducing the empiricism in the constitutive models should make it more acceptable to extrapolate FEAST-METAL to new fuel compositions and higher burnup, as envisioned in advanced sodium reactors

  6. Scrotal swelling

    MedlinePlus

    ... determine whether you need any tests. Your health care provider may prescribe antibiotics and pain medications, or recommend surgery. A scrotal ultrasound may be done to find where the swelling is occurring.

  7. POWER GENERATION FROM LIQUID METAL NUCLEAR FUEL

    DOEpatents

    Dwyer, O.E.

    1958-12-23

    A nuclear reactor system is described wherein the reactor is the type using a liquid metal fuel, such as a dispersion of fissile material in bismuth. The reactor is designed ln the form of a closed loop having a core sectlon and heat exchanger sections. The liquid fuel is clrculated through the loop undergoing flssion in the core section to produce heat energy and transferrlng this heat energy to secondary fluids in the heat exchanger sections. The fission in the core may be produced by a separate neutron source or by a selfsustained chain reaction of the liquid fuel present in the core section. Additional auxiliary heat exchangers are used in the system to convert water into steam which drives a turbine.

  8. Coking of JP-4 fuels in electrically heated metal tubes

    NASA Technical Reports Server (NTRS)

    Smith, Arthur L; Cook, William P; Hlavin, Vincent F

    1956-01-01

    A limited exploratory investigation of the rate of coking of four JP-4 fuels in electrically heated metal tubes was conducted in order to provide design information for fuel prevaporizers for turbojet-engine combustors. The fuels tested included two production and two minimum-quality JP-4 type fuels. The heating tube was operated at fuel pressures of approximately 500, 400, and 50 pounds per square inch. The operating fuel temperature was varied between approximately 600 degrees and 1200 degrees F.

  9. An in-situ nano-scale swelling-filling strategy to improve overall performance of Nafion membrane for direct methanol fuel cell application

    NASA Astrophysics Data System (ADS)

    Li, Jing; Fan, Kun; Cai, Weiwei; Ma, Liying; Xu, Guoxiao; Xu, Sen; Ma, Liang; Cheng, Hansong

    2016-11-01

    A novel in-situ nano-scale swelling-filling (SF) strategy is proposed to modify commercial Nafion membranes for performance enhancement of direct methanol fuel cells (DMFCs). A Nafion membrane was filled in-situ with proton conductive macromolecules (PCMs) in the swelling process of a Nafion membrane in a PCM solution. As a result, both proton conductivity and methanol-permeation resistivity of the SF-treated Naifion membrane was substantially improved with the selectivity nearly doubled compared to the original Nafion membrane. The mechanical strength of the optimal SF treated Nafion membrane was also enforced due to the strong interaction between the PCM fillers and the Nafion molecular chains. As a result, a DMFC equipped with the SF-treated membrane yielded a 33% higher maximum power density than that offered by the DMFC with the original Nafion membrane.

  10. Precious Metal Recovery from Fuel Cell MEA's

    SciTech Connect

    Lawrence Shore

    2004-04-25

    In 2003, Engelhard Corporation received a DOE award to develop a cost-effective, environmentally friendly approach to recover Pt from fuel cell membrane electrode assemblies (MEA’s). The most important precious metal used in fuel cells is platinum, but ruthenium is also added to the anode electrocatalyst if CO is present in the hydrogen stream. As part of the project, a large number of measurements of Pt and Ru need to be made. A low-cost approach to measuring Pt is using the industry standard spectrophotometric measurement of Pt complexed with stannous chloride. The interference of Ru can be eliminated by reading the Pt absorbance at 450 nm. Spectrophotometric methods for measuring Ru, while reported in the literature, are not as robust. This paper will discuss the options for measuring Pt and Ru using the method of UV-VIS spectrophotometry

  11. Performance limit analysis of a metallic fuel for Kalimer

    SciTech Connect

    Lee, Byoung Oon; Cheon, J.S.; Lee, C.B.

    2007-07-01

    A metallic fuel is being considered as the fuel for SFR in Korea. The metal fuel development for SFR in Korea started in 2007 in the areas of metal fuel fabrication, cladding materials and fuel performance evaluation. The MACSIS code for a metallic fuel has been developed as a steady-state performance computer code. Present study represents the preliminary parametric results for evaluating the design limits of the metal fuel for SFR in Korea. The operating limits were analyzed by the MACSIS code. The modules of the creep rupture strength for the Mod.HT9 and the barrier cladding were inserted. The strain limits and the CDF limit were analyzed for the HT9, and the Mod.HT9. To apply the concept of a barrier cladding, the burnup limit of the barrier cladding was analyzed. (authors)

  12. Compatibility Study for Plastic, Elastomeric, and Metallic Fueling Infrastructure Materials Exposed to Aggressive Formulations of Ethanol-blended Gasoline

    SciTech Connect

    Kass, Michael D; Pawel, Steven J; Theiss, Timothy J; Janke, Christopher James

    2012-07-01

    In 2008 Oak Ridge National Laboratory began a series of experiments to evaluate the compatibility of fueling infrastructure materials with intermediate levels of ethanol-blended gasoline. Initially, the focus was elastomers, metals, and sealants, and the test fuels were Fuel C, CE10a, CE17a and CE25a. The results of these studies were published in 2010. Follow-on studies were performed with an emphasis on plastic (thermoplastic and thermoset) materials used in underground storage and dispenser systems. These materials were exposed to test fuels of Fuel C and CE25a. Upon completion of this effort, it was felt that additional compatibility data with higher ethanol blends was needed and another round of experimentation was performed on elastomers, metals, and plastics with CE50a and CE85a test fuels. Compatibility of polymers typically relates to the solubility of the solid polymer with a solvent. It can also mean susceptibility to chemical attack, but the polymers and test fuels evaluated in this study are not considered to be chemically reactive with each other. Solubility in polymers is typically assessed by measuring the volume swell of the polymer exposed to the solvent of interest. Elastomers are a class of polymers that are predominantly used as seals, and most o-ring and seal manufacturers provide compatibility tables of their products with various solvents including ethanol, toluene, and isooctane, which are components of aggressive oxygenated gasoline as described by the Society of Automotive Engineers (SAE) J1681. These tables include a ranking based on the level of volume swell in the elastomer associated with exposure to a particular solvent. Swell is usually accompanied by a decrease in hardness (softening) that also affects performance. For seal applications, shrinkage of the elastomer upon drying is also a critical parameter since a contraction of volume can conceivably enable leakage to occur. Shrinkage is also indicative of the removal of one or more

  13. Recent progress in the development of metallic fuel

    SciTech Connect

    Seidel, B.R.; Batte, G.L.; Dodds, N.E.; Lahm, C.E.; Pahl, R.G. ); Tsai, H.C. )

    1990-01-01

    Tests to date demonstrate that metallic fuel for advanced liquid metal reactors performs well, is easily reprocessed and refabricated and provides inherent reactor safety within an economic design. The behavior and performance of metallic fuel is key to the demonstration of the Integral Fast Reactor (IFR) concept at Argonne National Laboratory. Since 1985, more than 40 assemblies of experimental fuel in addition to the standard metallic driver fuel for Experimental Breeder Reactor 2 (EBR-2)have been irradiated; several more continue to be designed and fabricated. Results have characterized the influence of a wide range of fabrication, design and material variables upon irradiation behavior throughout the fuel lifetime under normal and upset conditions including operation with breached cladding. Results of test, both in- and out-of-reactor, indicate that metallic fuel is readily and economically fabricated, capable of achieving high exposure and long reactor residence times, and possesses unique and promising safety features. 9 refs., 6 figs.

  14. Viscosity Meaurement Technique for Metal Fuels

    SciTech Connect

    Ban, Heng; Kennedy, Rory

    2015-02-09

    Metallic fuels have exceptional transient behavior, excellent thermal conductivity, and a more straightforward reprocessing path, which does not separate out pure plutonium from the process stream. Fabrication of fuel containing minor actinides and rare earth (RE) elements for irradiation tests, for instance, U-20Pu-3Am-2Np-1.0RE-15Zr samples at the Idaho National Laboratory, is generally done by melt casting in an inert atmosphere. For the design of a casting system and further scale up development, computational modeling of the casting process is needed to provide information on melt flow and solidification for process optimization. Therefore, there is a need for melt viscosity data, the most important melt property that controls the melt flow. The goal of the project was to develop a measurement technique that uses fully sealed melt sample with no Americium vapor loss to determine the viscosity of metallic melts and at temperatures relevant to the casting process. The specific objectives of the project were to: develop mathematical models to establish the principle of the measurement method, design and build a viscosity measurement prototype system based on the established principle, and calibrate the system and quantify the uncertainty range. The result of the project indicates that the oscillation cup technique is applicable for melt viscosity measurement. Detailed mathematical models of innovative sample ampoule designs were developed to not only determine melt viscosity, but also melt density under certain designs. Measurement uncertainties were analyzed and quantified. The result of this project can be used as the initial step toward the eventual goal of establishing a viscosity measurement system for radioactive melts.

  15. Fabrication and Preliminary Evaluation of Metal Matrix Microencapsulated Fuels

    SciTech Connect

    Terrani, Kurt A; Kiggans, Jim; Snead, Lance Lewis

    2012-01-01

    The metal matrix microencapsulated (M3) fuel concept for light water reactors (LWRs), consisting of coated fuel particles dispersed in a zirconium metal matrix, is introduced. Fabrication of M3 fuels by hot pressing, hot isostatic pressing, or extrusion methodologies has been demonstrated over the temperature range 800-1050 C. Various types of coated fuel particles with outermost layers of pyrocarbon, SiC, ZrC, and TiN have been incorporated into the zirconium metal matrix. Mechanical particle-particle and chemical particle-matrix interactions have been observed during the preliminary characterization of as-fabricated M3 specimens. Irradiation of three M3 rodlets with surrogate coated fuel particles was carried out at mean rod temperature of 400 C to 4.6 dpa in the zirconium metal matrix. Due to absence of texture in the metal matrix no irradiation growth strain (<0.09%) was detected during the post-irradiation examination.

  16. Swelling of phospholipid membranes by divalent metal ions depends on the location of the ions in the bilayers.

    PubMed

    Alsop, Richard J; Maria Schober, Rafaëla; Rheinstädter, Maikel C

    2016-08-10

    The Hofmeister series illustrates how salts produce a wide range of effects in biological systems, which are not exclusively explained by ion charge. In lipid membranes, charged ions have been shown to bind to lipids and either hydrate or dehydrate lipid head groups, and also to swell the water layer in multi-lamellar systems. Typically, Hofmeister phenomena are explained by the interaction of the ions with water, as well as with biological interfaces, such as proteins or membranes. We studied the effect of the divalent cations Mg(2+), Ca(2+), Fe(2+), and Zn(2+) on oriented, stacked, phospholipid bilayers made of dimyristoylphosphatidylcholine (DMPC). Using high-resolution X-ray diffraction, we observed that the cations lead to a swelling of the water layer between the bilayers, without causing significant changes to the bilayer structure. The cations swelled the bilayers in different amounts, in the order Fe(2+) > Mg(2+) > Ca(2+) > Zn(2+). By decomposing the total bilayer electron density into different molecular groups, Zn(2+) and Ca(2+) were found to interact with the glycerol groups of the lipid molecules and cause minor swelling of the bilayers. Mg(2+) and Fe(2+) were found to position near the phosphate groups and cause a strong increase in the number of hydration water molecules. Our results present a molecular mechanism-of-action for the Hofmeister series in phospholipid membranes. PMID:27453289

  17. Nanotechnology Investigated for Future Gelled and Metallized Gelled Fuels

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan A.

    2003-01-01

    The objective of this research is to create combustion data for gelled and metallized gelled fuels using unique nanometer-sized gellant particles and/or nanometer-sized aluminum particles. Researchers at the NASA Glenn Research Center are formulating the fuels for both gas turbine and pulsed detonation engines. We intend to demonstrate metallized gelled fuel ignition characteristics for pulse detonation engines with JP/aluminum fuel and for gas turbine engines with gelled JP, propane, and methane fuel. The fuels to be created are revolutionary as they will deliver the highest theoretically maximum performance of gelled and metallized gelled fuels. Past combustion work has used micrometer-sized particles, which have limited the combustion performance of gelled and metallized gelled fuels. The new fuel used nanometer-sized aluminum oxide particles, which reduce the losses due to mismatch in the gas and solid phases in the exhaust. Gelled fuels provide higher density, added safety, reduced fuel slosh, reduced leakage, and increased exhaust velocity. Altogether, these benefits reduce the overall size and mass of the vehicle, increasing its flexibility.

  18. The DART dispersion analysis research tool: A mechanistic model for predicting fission-product-induced swelling of aluminum dispersion fuels. User`s guide for mainframe, workstation, and personal computer applications

    SciTech Connect

    Rest, J.

    1995-08-01

    This report describes the primary physical models that form the basis of the DART mechanistic computer model for calculating fission-product-induced swelling of aluminum dispersion fuels; the calculated results are compared with test data. In addition, DART calculates irradiation-induced changes in the thermal conductivity of the dispersion fuel, as well as fuel restructuring due to aluminum fuel reaction, amorphization, and recrystallization. Input instructions for execution on mainframe, workstation, and personal computers are provided, as is a description of DART output. The theory of fission gas behavior and its effect on fuel swelling is discussed. The behavior of these fission products in both crystalline and amorphous fuel and in the presence of irradiation-induced recrystallization and crystalline-to-amorphous-phase change phenomena is presented, as are models for these irradiation-induced processes.

  19. Metallic fuels: The EBR-II legacy and recent advances

    SciTech Connect

    Douglas L. Porter; Steven L. Hayes; J. Rory Kennedy

    2012-09-01

    Experimental Breeder Reactor – II (EBR-II) metallic fuel was qualified for high burnup to approximately 10 atomic per cent. Subsequently, the electrometallurgical treatment of this fuel was demonstrated. Advanced metallic fuels are now investigated for increased performance, including ultra-high burnup and actinide burning. Advances include additives to mitigate the fuel/cladding chemical interaction and uranium alloys that combine Mo, Ti and Zr to improve alloy performance. The impacts of the advances—on fabrication, waste streams, electrorefining, etc.—are found to be minimal and beneficial. Owing to extensive research literature and computational methods, only a modest effort is required to complete their development.

  20. Fuel cell with metal screen flow-field

    DOEpatents

    Wilson, M.S.; Zawodzinski, C.

    1998-08-25

    A polymer electrolyte membrane (PEM) fuel cell is provided with electrodes supplied with a reactant on each side of a catalyzed membrane assembly (CMA). The fuel cell includes a metal mesh defining a rectangular flow-field pattern having an inlet at a first corner and an outlet at a second corner located on a diagonal from the first corner, wherein all flow paths from the inlet to the outlet through the square flow field pattern are equivalent to uniformly distribute the reactant over the CMA. In a preferred form of metal mesh, a square weave screen forms the flow-field pattern. In a particular characterization of the present invention, a bipolar plate electrically connects adjacent fuel cells, where the bipolar plate includes a thin metal foil having an anode side and a cathode side; a first metal mesh on the anode side of the thin metal foil; and a second metal mesh on the cathode side of the thin metal foil. In another characterization of the present invention, a cooling plate assembly cools adjacent fuel cells, where the cooling plate assembly includes an anode electrode and a cathode electrode formed of thin conducting foils; and a metal mesh flow field there between for distributing cooling water flow over the electrodes to remove heat generated by the fuel cells. 11 figs.

  1. Fuel cell with metal screen flow-field

    DOEpatents

    Wilson, Mahlon S.; Zawodzinski, Christine

    2001-01-01

    A polymer electrolyte membrane (PEM) fuel cell is provided with electrodes supplied with a reactant on each side of a catalyzed membrane assembly (CMA). The fuel cell includes a metal mesh defining a rectangular flow-field pattern having an inlet at a first corner and an outlet at a second corner located on a diagonal from the first corner, wherein all flow paths from the inlet to the outlet through the square flow field pattern are equivalent to uniformly distribute the reactant over the CMA. In a preferred form of metal mesh, a square weave screen forms the flow-field pattern. In a particular characterization of the present invention, a bipolar plate electrically connects adjacent fuel cells, where the bipolar plate includes a thin metal foil having an anode side and a cathode side; a first metal mesh on the anode side of the thin metal foil; and a second metal mesh on the cathode side of the thin metal foil. In another characterization of the present invention, a cooling plate assembly cools adjacent fuel cells, where the cooling plate assembly includes an anode electrode and a cathode electrode formed of thin conducting foils; and a metal mesh flow field therebetween for distributing cooling water flow over the electrodes to remove heat generated by the fuel cells.

  2. Fuel cell with metal screen flow-field

    DOEpatents

    Wilson, Mahlon S.; Zawodzinski, Christine

    1998-01-01

    A polymer electrolyte membrane (PEM) fuel cell is provided with electrodes supplied with a reactant on each side of a catalyzed membrane assembly (CMA). The fuel cell includes a metal mesh defining a rectangular flow-field pattern having an inlet at a first corner and an outlet at a second corner located on a diagonal from the first corner, wherein all flow paths from the inlet to the outlet through the square flow field pattern are equivalent to uniformly distribute the reactant over the CMA. In a preferred form of metal mesh, a square weave screen forms the flow-field pattern. In a particular characterization of the present invention, a bipolar plate electrically connects adjacent fuel cells, where the bipolar plate includes a thin metal foil having an anode side and a cathode side; a first metal mesh on the anode side of the thin metal foil; and a second metal mesh on the cathode side of the thin metal foil. In another characterization of the present invention, a cooling plate assembly cools adjacent fuel cells, where the cooling plate assembly includes an anode electrode and a cathode electrode formed of thin conducting foils; and a metal mesh flow field therebetween for distributing cooling water flow over the electrodes to remove heat generated by the fuel cells.

  3. Highly Dispersed Metal Catalyst for Fuel Cell Electrodes

    SciTech Connect

    2009-03-01

    This factsheet describes a study that will bring industrial catalyst experience to fuel cell research. Specifically, industrial catalysts, such as those used in platforming, utilize precious metal platinum as an active component in a finely dispersed form.

  4. Dimensional, microstructural and compositional stability of metal fuels

    SciTech Connect

    Solomon, A.A.; Dayananda, M.A.

    1993-03-15

    The projects undertaken were to address two areas of concern for metal-fueled fast reactors: metallurgical compatibility of fuel and its fission products with the stainless steel cladding, and effects of porosity development in the fuel on fuel/cladding interactions and on sodium penetration in fuel. The following studies are reported on extensively in appendices: hot isostatic pressing of U-10Zr by coupled boundary diffusion/power law creep cavitation, liquid Na intrusion into porous U-10Zr fuel alloy by differential capillarity, interdiffusion between U-Zr fuel and selected Fe-Ni-Cr alloys, interdiffusion between U-Zr fuel vs selected cladding steels, and interdiffusion of Ce in Fe-base alloys with Ni or Cr.

  5. Novel fuel cell stack with coupled metal hydride containers

    NASA Astrophysics Data System (ADS)

    Liu, Zhixiang; Li, Yan; Bu, Qingyuan; Guzy, Christopher J.; Li, Qi; Chen, Weirong; Wang, Cheng

    2016-10-01

    Air-cooled, self-humidifying hydrogen fuel cells are often used for backup and portable power sources, with a metal hydride used as the hydrogen storage material. To provide a stable hydrogen flow to the fuel cell stack, heat must be provided to the metal hydride. Conventionally, the heat released from the exothermic reaction of hydrogen and oxygen in the fuel cell stack to the exhaust air is used to heat a separate metal hydride container. In this case, the heat is only partially used instead of being more closely coupled because of the heat transfer resistances in the system. To achieve better heat integration, a novel scheme is proposed whereby hydrogen storage and single fuel cells are more closely coupled. Based on this idea, metal hydride containers in the form of cooling plates were assembled between each pair of cells in the stack so that the heat could be directly transferred to a metal hydride container of much larger surface-to-volume ratio than conventional separate containers. A heat coupled fuel cell portable power source with 10 cells and 11 metal hydride containers was constructed and the experimental results show that this scheme is beneficial for the heat management of fuel cell stack.

  6. Foot, leg, and ankle swelling

    MedlinePlus

    Swelling of the ankles - feet - legs; Ankle swelling; Foot swelling; Leg swelling; Edema - peripheral; Peripheral edema ... Painless swelling may affect both legs and may include the calves or ... of gravity makes the swelling most noticeable in the lower ...

  7. Production of metal waste forms from spent fuel treatment

    SciTech Connect

    Westphal, B.R.; Keiser, D.D.; Rigg, R.H.; Laug, D.V.

    1995-02-01

    Treatment of spent nuclear fuel at Argonne National Laboratory consists of a pyroprocessing scheme in which the development of suitable waste forms is being advanced. Of the two waste forms being proposed, metal and mineral, the production of the metal waste form utilizes induction melting to stabilize the waste product. Alloying of metallic nuclear materials by induction melting has long been an Argonne strength and thus, the transition to metallic waste processing seems compatible. A test program is being initiated to coalesce the production of the metal waste forms with current induction melting capabilities.

  8. A novel microstructured metal-supported solid oxide fuel cell

    NASA Astrophysics Data System (ADS)

    Fernández-González, R.; Hernández, E.; Savvin, S.; Núñez, P.; Makradi, A.; Sabaté, N.; Esquivel, J. P.; Ruiz-Morales, J. C.

    2014-12-01

    An innovative design, alternative to the conventional metal supported fuel cells (MSC) is proposed. This new design of Solid Oxide Fuel Cell (SOFC), comprises a 200 μm layer of a honeycomb-metallic framework with hexagonal cells which supports a 250 μm layer of electrolyte. Each hexagonal cell is further functionalized with a thin 5-10 μm of Ni-YSZ anode. This new design allows a reduction of ∼65% of the metallic supporting material, rendering performances over 300 mW cm-2 under pure hydrogen at 850 °C, with an OCV of ∼1.1 V.

  9. Modeling of constituent redistribution in U Pu Zr metallic fuel

    NASA Astrophysics Data System (ADS)

    Kim, Yeon Soo; Hayes, S. L.; Hofman, G. L.; Yacout, A. M.

    2006-12-01

    A computer model was developed to analyze constituent redistribution in U-Pu-Zr metallic nuclear fuels. Diffusion and thermochemical properties were parametrically determined to fit the postirradiation data from a fuel test performed in the Experimental Breeder Reactor II (EBR-II). The computer model was used to estimate redistribution profiles of fuels proposed for the conceptual designs of small modular fast reactors. The model results showed that the level of redistribution of the fuel constituents of the designs was similar to the measured data from EBR-II.

  10. Metallic Fuel Casting Development and Parameter Optimization Simulations

    SciTech Connect

    R.S. Fielding; J. Crapps; C. Unal; J.R. Kennedy

    2013-03-01

    One of the advantages of metallic fuel is the abilility to cast the fuel slugs to near net shape with little additional processing. However, the high aspect ratio of the fuel is not ideal for casting. EBR-II fuel was cast using counter gravity injection casting (CGIC) but, concerns have been raised concerning the feasibility of this process for americium bearing alloys. The Fuel Cycle Research and Development program has begun developing gravity casting techniques suitable for fuel production. Compared to CGIC gravity casting does not require a large heel that then is recycled, does not require application of a vacuum during melting, and is conducive to re-usable molds. Development has included fabrication of two separate benchscale, approximately 300 grams, systems. To shorten development time computer simulations have been used to ensure mold and crucible designs are feasible and to identify which fluid properties most affect casting behavior and therefore require more characterization.

  11. Modeling Constituent Redistribution in U-Pu-Zr Metallic Fuel Using the Advanced Fuel Performance Code BISON

    SciTech Connect

    Douglas Porter; Steve Hayes; Various

    2014-06-01

    The Advanced Fuels Campaign (AFC) metallic fuels currently being tested have higher zirconium and plutonium concentrations than those tested in the past in EBR reactors. Current metal fuel performance codes have limitations and deficiencies in predicting AFC fuel performance, particularly in the modeling of constituent distribution. No fully validated code exists due to sparse data and unknown modeling parameters. Our primary objective is to develop an initial analysis tool by incorporating state-of-the-art knowledge, constitutive models and properties of AFC metal fuels into the MOOSE/BISON (1) framework in order to analyze AFC metallic fuel tests.

  12. Metal matrix composite fuel for space radioisotope energy sources

    NASA Astrophysics Data System (ADS)

    Williams, H. R.; Ning, H.; Reece, M. J.; Ambrosi, R. M.; Bannister, N. P.; Stephenson, K.

    2013-02-01

    Radioisotope fuels produce heat that can be used for spacecraft thermal control or converted to electricity. They must retain integrity in the event of destruction or atmospheric entry of the parent spacecraft. Addition of a metal matrix to the actinide oxide could yield a more robust fuel form. Neodymium (III) oxide (Nd2O3) - niobium metal matrix composites were produced using Spark Plasma Sintering; Nd2O3 is a non-radioactive surrogate for americium (III) oxide (Am2O3). Two compositions, 70 and 50 wt% Nd2O3, were mechanically tested under equibiaxial (ring-on-ring) flexure according to ASTM C1499. The addition of the niobium matrix increased the mean flexural strength by a factor of about 2 compared to typical ceramic nuclear fuels, and significantly increased the Weibull modulus to over 20. These improved mechanical properties could result in reduced fuel dispersion in severe accidents and improved safety of space radioisotope power systems.

  13. Apparatus for injection casting metallic nuclear energy fuel rods

    SciTech Connect

    Seidel, B.R.; Tracy, D.B.; Griffiths, V.

    1991-09-03

    Molds for making metallic nuclear fuel rods are provided which present reduced risks to the environment by reducing radioactive waste. In one embodiment, the mold is consumable with the fuel rod, and in another embodiment, part of the mold can be re-used. Several molds can be arranged together in a cascaded manner, if desired, or several long cavities can be integrated in a monolithic multiple cavity re-usable mold.

  14. Apparatus for injection casting metallic nuclear energy fuel rods

    SciTech Connect

    Seidel, Bobby R.; Tracy, Donald B.; Griffiths, Vernon

    1991-01-01

    Molds for making metallic nuclear fuel rods are provided which present reduced risks to the environment by reducing radioactive waste. In one embodiment, the mold is consumable with the fuel rod, and in another embodiment, part of the mold can be re-used. Several molds can be arranged together in a cascaded manner, if desired, or several long cavities can be integrated in a monolithic multiple cavity re-usable mold.

  15. Low Cost PEM Fuel Cell Metal Bipolar Plates

    SciTech Connect

    Wang, Conghua

    2013-05-30

    Bipolar plate is an important component in fuel cell stacks and accounts for more than 75% of stack weight and volume. The technology development of metal bipolar plates can effectively reduce the fuel cells stack weight and volume over 50%. The challenge is the metal plate corrosion protection at low cost for the broad commercial applications. This project is aimed to develop innovative technological solutions to overcome the corrosion barrier of low cost metal plates. The feasibility of has been demonstrated and patented (US Patent 7,309,540). The plan is to further reduce the cost, and scale up the technology. The project is built on three pillars: 1) robust experimental evidence demonstrating the feasibility of our technology, 2) a team that consists of industrial leaders in fuel cell stack application, design, and manufactures; 3) a low-risk, significant-milestone driven program that proves the feasibility of meeting program objectives The implementation of this project will reduce the fuel cell stack metal bipolar separator plate cost which accounts 15-21% of the overall stack cost. It will contribute to the market adoption of fuel cell technologies. In addition, this corrosion protection technology can be used similar energy devices, such as batteries and electrolyzers. Therefore, the success of the project will be benefit in broad markets.

  16. Temperature and burnup correlated fuel-cladding chemical interaction in U-10ZR metallic fuel

    NASA Astrophysics Data System (ADS)

    Carmack, William J.

    Metallic fuels are proposed for use in advanced sodium cooled fast reactors and provide a number of advantages over other fuel types considering their fabricability, performance, recyclability, and safety. Resistance to cladding "breach" and subsequent release of fission products and fuel constituents to the nuclear power plant primary coolant system is a key performance parameter for a nuclear fuel system. In metallic fuel, FCCI weakens the cladding, especially at high power-high temperature operation, contributing to fuel pin breach. Empirical relationships for FCCI have been developed from a large body of data collected from in-pile (EBR-II) and out-of-pile experiments [1]. However, these relationships are unreliable in predicting FCCI outside the range of EBR-II experimental data. This dissertation examines new FCCI data extracted from the MFF-series of prototypic length metallic fuel irradiations performed in the Fast Flux Test Facility (FFTF). The fuel in these assemblies operated a temperature and burnup conditions similar to that in EBR-II but with axial fuel height three times longer than EBR-II experiments. Comparing FCCI formation data from FFTF and EBR-II provides new insight into FCCI formation kinetics. A model is developed combining both production and diffusion of lanthanides to the fuel-cladding interface and subsequent reaction with the cladding. The model allows these phenomena to be influenced by fuel burnup (lanthanide concentrations) and operating temperature. Parameters in the model are adjusted to reproduce measured FCCI layer thicknesses from EBR-II and FFTF. The model predicts that, under appropriate conditions, rate of FCCI formation can be controlled by either fission product transport or by the reaction rate of the interaction species at the fuel-cladding interface. This dissertation will help forward the design of metallic fuel systems for advanced sodium cooled fast reactors by allowing the prediction of FCCI layer formation in full

  17. Coated metal sintering carriers for fuel cell electrodes

    DOEpatents

    Donelson, R.; Bryson, E.S.

    1998-11-10

    A carrier is described for conveying components of a fuel cell to be sintered through a sintering furnace. The carrier comprises a metal sheet coated with a water-based carbon paint, the water-based carbon paint comprising water, powdered graphite, an organic binder, a wetting agent, a dispersing agent and a defoaming agent.

  18. Yttrium and rare earth stabilized fast reactor metal fuel

    SciTech Connect

    Guon, J.; Grantham, L.F.; Specht, E.R.

    1992-05-12

    This patent describes an improved metal alloy reactor fuel consisting essentially of uranium, plutonium, and at least one element from the group consisting of yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.

  19. Coated metal sintering carriers for fuel cell electrodes

    SciTech Connect

    Donelson, Richard; Bryson, E. S.

    1998-01-01

    A carrier for conveying components of a fuel cell to be sintered through a sintering furnace. The carrier comprises a metal sheet coated with a water-based carbon paint, the water-based carbon paint comprising water, powdered graphite, an organic binder, a wetting agent, a dispersing agent and a defoaming agent.

  20. Assessment of ceramic coatings for metal fuel melting crucible

    SciTech Connect

    Kim, Ki-Hwan; Song, Hoon; Kim, Jong-Hwan; Oh, Seok-Jin; Kim, Hyung-Tae; Lee, Chan-Bock

    2013-07-01

    The objective of this study is to develop a coating method and material for crucibles to prevent material interactions with the U-Zr/U-TRU-Zr fuels during the manufacturing of SFR fuels. Refractory coatings were applied to niobium substrates by vacuum plasma-spray coating method. Melt dipping tests conducted were the coated rods lowered into the fuel melt at 1600 C. degrees, and withdrawn and cooled outside the crucible in the inert atmosphere of the induction furnace. Melt dipping tests of the coated Nb rods indicated that plasma-sprayed Y{sub 2}O{sub 3} coating doesn't form significant reaction layer between fuel melt and coating layer. Melt dipping tests of the coated Nb rods showed that TiC, TaC, and Y{sub 2}O{sub 3} coatings exhibited the promising performance among other ceramic coatings. These materials could be promising candidate materials for the reusable melt crucible of metal fuel for SFR. In addition, in order to develop the vacuum plasma-spray coating method for re-usable crucible of metal fuel slugs to be overcome the issue of thermal expansion mismatch between coating material and crucible, various combinations of coating conditions were investigated to find the bonding effect on the substrate in pursuit of more effective ways to withstand the thermal stresses. It is observed that most coating methods maintained sound coating state in U-Zr melt. (authors)

  1. Emissions of fuel metals content from a diesel vehicle engine

    NASA Astrophysics Data System (ADS)

    Wang, Ya-Fen; Huang, Kuo-Lin; Li, Chun-Teh; Mi, Hsiao-Hsuan; Luo, Jih-Haur; Tsai, Perng-Jy

    This study was set out to assess the characteristics and significance of metal contents emitted from diesel engines. We found that the emitted concentrations of crust elements (including Al, Ca, Fe, Mg, and Si) were much higher than those of anthropogenic elements (including Ag, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Sr, Ti, V, and Zn) from diesel vehicle engine exhausts under the transient-cycle condition. The emission concentrations of particulate matters from diesel vehicle engine were inversely proportional to the specified engine speeds. To the contrary, the increase of engine speeds resulted in increase of fractions of metal contents in particulate matters. We conducted simple linear regression analysis to relate the emission rates of the metal contents in vehicle exhaust to the consumption rates of metal contents in diesel fuel. This study yielded R2=0.999 which suggests that the emission of the metal contents in vehicle exhaust could be fully explained by the consumption of metal contents in diesel fuel. For illustration, we found that the annual emission rates of both crust and anthropogenic elements from all diesel engine vehicles (=269 000 and 58 700 kg yr -1, respectively) were significantly higher than those from the coal power plant, electrical arc furnace, and coke oven (=90 100 and 1660 kg yr -1, 2060 and 173 kg yr -1, and 60 500 and 3740 kg yr -1, respectively) in Taiwan area. The relatively high amount of metal contents emitted from diesel engines strongly suggests that the measurement on the control of metal contents in diesel fuel should be taken in the future.

  2. Swell Sleeves for Testing Explosive Devices

    NASA Technical Reports Server (NTRS)

    Hinkel, Todd J.; Dean, Richard J.; Hohmann, Carl W.; Hacker, Scott C.; Harrington, Douglas W.; Bacak, James W.

    2003-01-01

    A method of testing explosive and pyrotechnic devices involves exploding the devices inside swell sleeves. Swell sleeves have been used previously for measuring forces. In the present method, they are used to obtain quantitative indications of the energy released in explosions of the devices under test. A swell sleeve is basically a thick-walled, hollow metal cylinder threaded at one end to accept a threaded surface on a device to be tested (see Figure 1). Once the device has been tightly threaded in place in the swell sleeve, the device-and-swell-sleeve assembly is placed in a test fixture, then the device is detonated. After the explosion, the assembly is removed from the test fixture and placed in a coordinate-measuring machine for measurement of the diameter of the swell sleeve as a function of axial position. For each axial position, the original diameter of the sleeve is subtracted from the diameter of the sleeve as swollen by the explosion to obtain the diametral swelling as a function of axial position (see Figure 2). The amount of swelling is taken as a measure of the energy released in the explosion. The amount of swelling can be compared to a standard amount of swelling to determine whether the pyrotechnic device functioned as specified.

  3. Metal hydride fuel storage and method thereof

    DOEpatents

    Morse, Jeffrey D.; Jankowski, Alan F.; Yu, Conrad

    2010-08-10

    An apparatus having a first substrate having (1) a cavity, (2) one or more resistive heaters, and (3) one or more coatings forming a diffusion barrier to hydrogen; a second substrate having (1) an outlet valve comprising a pressure relief structure and (2) one or more coatings forming a diffusion barrier to hydrogen, wherein said second substrate is coupled to said first substrate forming a sealed volume in said cavity; a metal hydride material contained within said cavity; and a gas distribution system formed by coupling a microfluidic interconnect to said pressure relief structure. Additional apparatuses and methods are also disclosed.

  4. Degradation of solid oxide fuel cell metallic interconnects in fuels containing sulfur

    SciTech Connect

    Ziomek-Moroz, M.; Hawk, Jeffrey A.

    2005-01-01

    Hydrogen is the main fuel for all types of fuel cells except direct methanol fuel cells. Hydrogen can be generated from all manner of fossil fuels, including coal, natural gas, diesel, gasoline, other hydrocarbons, and oxygenates (e.g., methanol, ethanol, butanol, etc.). Impurities in the fuel can cause significant performance problems and sulfur, in particular, can decrease the cell performance of fuel cells, including solid oxide fuel cells (SOFC). In the SOFC, the high (800-1000°C) operating temperature yields advantages (e.g., internal fuel reforming) and disadvantages (e.g., material selection and degradation problems). Significant progress in reducing the operating temperature of the SOFC from ~1000 ºC to ~750 ºC may allow less expensive metallic materials to be used for interconnects and as balance of plant (BOP) materials. This paper provides insight on the material performance of nickel, ferritic steels, and nickel-based alloys in fuels containing sulfur, primarily in the form of H2S, and seeks to quantify the extent of possible degradation due to sulfur in the gas stream.

  5. Review of fuel/cladding eutectic formation in metallic SFR fuel pins

    SciTech Connect

    Denman, M.; Todreas, N.; Driscoll, M.

    2012-07-01

    Sodium-cooled Fast Reactors (SFRs) remain a strong contender amongst the Generation IV reactor concepts. Metallic fuel has been a primary fuel option for SFR designers in the US and was used extensively in the first generation of SFRs. One of the benefits of metallic fuel is its chemical compatibility with the coolant; unfortunately this compatibility does not extend to steel cladding at elevated temperatures. It has been known that uranium, plutonium, and rare earths diffuse with cladding constituents to form a low melting point fuel/cladding eutectic which acts to thin the cladding once the interfacial temperature rises above the system liquidus temperature. Since the 1960's, many experiments have been performed and published to evaluate the rate of fuel/cladding eutectic formation and the temperature above which melting will begin as a function of fuel/cladding interfacial temperature, time at temperature, fuel constituents (uranium, fissium or uranium (plutonium) zirconium), cladding type (stainless steel 316, stainless steel 306, D9 or HT9), beginning of life linear power, plutonium enrichment and burnup. The results of these tests, however, remain scattered across conference and journal papers spanning 50 years. The tests used to collect this data also varied in experimental procedure throughout the years. This paper will consolidate the experimental data into four groups of similar test conditions and expand upon the testing performed for each group in detail. A companion paper in PSA 2011 will discuss predictive correlations formulated from this database. (authors)

  6. Metallic hydrogen: The most powerful rocket fuel yet to exist

    NASA Astrophysics Data System (ADS)

    Silvera, Isaac F.; Cole, John W.

    2010-03-01

    Wigner and Huntington first predicted that pressures of order 25 GPa were required for the transition of solid molecular hydrogen to the atomic metallic phase. Later it was predicted that metallic hydrogen might be a metastable material so that it remains metallic when pressure is released. Experimental pressures achieved on hydrogen have been more than an order of magnitude higher than the predicted transition pressure and yet it remains an insulator. We discuss the applications of metastable metallic hydrogen to rocketry. Metastable metallic hydrogen would be a very light-weight, low volume, powerful rocket propellant. One of the characteristics of a propellant is its specific impulse, Isp. Liquid (molecular) hydrogen-oxygen used in modern rockets has an Isp of ~460s; metallic hydrogen has a theoretical Isp of 1700s! Detailed analysis shows that such a fuel would allow single-stage rockets to enter into orbit or carry economical payloads to the moon. If pure metallic hydrogen is used as a propellant, the reaction chamber temperature is calculated to be greater than 6000 K, too high for currently known rocket engine materials. By diluting metallic hydrogen with liquid hydrogen or water, the reaction temperature can be reduced, yet there is still a significant performance improvement for the diluted mixture.

  7. Method for producing hydrocarbon fuels and fuel gas from heavy polynuclear hydrocarbons by the use of molten metal halide catalysts

    DOEpatents

    Gorin, Everett

    1979-01-01

    In a process for hydrocracking heavy polynuclear carbonaceous feedstocks to produce lighter hydrocarbon fuels by contacting the heavy feedstocks with hydrogen in the presence of a molten metal halide catalyst in a hydrocracking zone, thereafter separating at least a major portion of the lighter hydrocarbon fuels from the spent molten metal halide and thereafter regenerating the spent molten metal halide by incinerating the spent molten metal halide by combustion of carbon and sulfur compounds in the spent molten metal halide in an incineration zone, the improvement comprising: (a) contacting the heavy feedstocks and hydrogen in the presence of the molten metal halide in the hydrocracking zone at reaction conditions effective to convert from about 60 to about 90 weight percent of the feedstock to lighter hydrocarbon fuels; (b) separating at least a major portion of the lighter hydrocarbon fuels from the spent molten metal halide; (c) contacting the spent molten metal halide with oxygen in a liquid phase gasification zone at a temperature and pressure sufficient to vaporize from about 25 to about 75 weight percent of the spent metal halide, the oxygen being introduced in an amount sufficient to remove from about 60 to about 90 weight percent of the carbon contained in the spent molten metal halide to produce a fuel gas and regenerated metal halide; and (d) incinerating the spent molten metal halide by combusting carbon and sulfur compounds contained therein.

  8. High performance, high durability non-precious metal fuel cell catalysts

    DOEpatents

    Wood, Thomas E.; Atanasoski, Radoslav; Schmoeckel, Alison K.

    2016-03-15

    This invention relates to non-precious metal fuel cell cathode catalysts, fuel cells that contain these catalysts, and methods of making the same. The fuel cell cathode catalysts are highly nitrogenated carbon materials that can contain a transition metal. The highly nitrogenated carbon materials can be supported on a nanoparticle substrate.

  9. Carbon composites with metal nanoparticles for Alcohol fuel cells

    NASA Astrophysics Data System (ADS)

    Ventrapragada, Lakshman; Siddhardha, R. S.; Podilla, Ramakrishna; Muthukumar, V. S.; Creager, Stephen; Rao, A. M.; Ramamurthy, Sai Sathish

    2015-03-01

    Graphene due to its high surface area and superior conductivity has attracted wide attention from both industrial and scientific communities. We chose graphene as a substrate for metal nanoparticle deposition for fuel cell applications. There are many chemical routes for fabrication of metal-graphene composites, but they have an inherent disadvantage of low performance due to the usage of surfactants, that adsorb on their surface. Here we present a design for one pot synthesis of gold nanoparticles and simultaneous deposition on graphene with laser ablation of gold strip and functionalized graphene. In this process there are two natural advantages, the nanoparticles are synthesized without any surfactants, therefore they are pristine and subsequent impregnation on graphene is linker free. These materials are well characterized with electron microscopy to find their morphology and spectroscopic techniques like Raman, UV-Vis. for functionality. This gold nanoparticle decorated graphene composite has been tested for its electrocatalytic oxidation of alcohols for alkaline fuel cell applications. An electrode made of this composite showed good stability for more than 200 cycles of operation and reported a low onset potential of 100 mV more negative, an important factor for direct ethanol fuel cells.

  10. Experimental Determination of Metal Fuel Point Defect Parameters

    SciTech Connect

    Fluss, M J; McCall, S

    2008-06-03

    Nuclear metallic fuels are one of many options for advanced nuclear fuel cycles because they provide dimensional stability, mechanical integrity, thermal efficiency, and irradiation resistance while the associated pyro-processing is technically relevant to concerns about proliferation and diversion of special nuclear materials. In this presentation we will discuss recent success that we have had in studying isochronal annealing of damage cascades in Pu and Pu(Ga) arising from the self-decay of Pu as well as the annealing characteristics of noninteracting point defect populations produced by ion accelerator irradiation. Comparisons of the annealing properties of these two populations of defects arising from very different source terms are enlightening and point to complex defect and mass transport properties in the plutonium specimens which we are only now starting to understand as a result of many follow-on studies. More importantly however, the success of these measurements points the way to obtaining important mass transport parameters for comparison with theoretical predictions or to use directly in existing and future materials modeling of radiation effects in nuclear metallic fuels. The way forward on such measurements and the requisite theory and modeling will be discussed.

  11. A precious-metal free micro fuel cell accumulator

    NASA Astrophysics Data System (ADS)

    Bretthauer, C.; Müller, C.; Reinecke, H.

    2011-05-01

    In recent years, integrated fuel cell (FC) type primary and secondary batteries attracted a great deal of attention as integrated on-chip power sources due to their high theoretical power densities. Unfortunately, the costs of these devices have been rather high. This is partially due to the involved clean-room processes, but also due to the fact that these devices generally rely on expensive precious-metals such as Pd and Pt. Therefore we developed a novel integrated FC type accumulator that is based on non-precious-metals only. The key component of the presented accumulator is its alkaline polymer electrolyte membrane that allows not only the usage of a low-cost AB5 type hydrogen storage electrode, but also the usage of La0.6Ca0.4CoO3 as a precious-metal free bifunctional catalyst for the air-breathing electrode. Additionally the presented design requires only comparatively few cleanroom processes which further reduces the overall production costs. Although abdicating precious-metals, the presented accumulator shows an open circuit voltage of 0.81 V and a maximum power density of 0.66 mW cm-2 which is comparable or even superior to former precious-metal based cells.

  12. Effect of a metal alloy fuel catalyst on bacterial growth.

    PubMed

    Ghosh, Ruma; Koerting, Claudia; Suib, Steven L; Best, Michael H; Berlin, Alvin J

    2005-11-01

    Many microorganisms have been demonstrated to utilize petroleum fuel products to fulfill their nutritional requirement for carbon. As a result, the ability of these microbes to degrade fuel has both a deleterious affect as well as beneficial applications. This study focused on the undesired ability of bacteria to grow on fuel and the potential for some metal alloys to inhibit this biodegradation. The objective of this study was to review the pattern of growth of two reference strains of petroleum-degrading bacteria, Pseudomonas oleovorans and Rhodococcus rhodocrous, in a specific hydrocarbon environment in the presence of a commercially available alloy. The alloy formulated and supplied by Advanced Power Systems International Inc. (APSI) is sold for fuel reformulation and other purposes. The components of the alloy used in the study were antimony, tin, lead, and mercury formulated as pellets. Surface characterization also showed the presence of tin oxide and lead amalgam phases. Hydrocarbon used for the study was primarily 87-octane gasoline. The growth of the bacteria in the water and mineral-supplemented gasoline mixture over 6-8 weeks was monitored by the viable plate count method. While an initial increase in bacteria occurred in the first week, overall bacterial growth was found to be suppressed in the presence of the alloy. Results also indicate that the alloy surface characteristics that convey the catalytic activity may also contribute to the observed antibacterial activity. PMID:16262333

  13. Fully-Coupled Metallic Fuel Performance Simulations using BISON

    SciTech Connect

    Galloway, Jack D.; Unal, Cetin

    2015-08-27

    This document is a set of slides intended to accompany a talk at a meeting. The first topic taken up is zirconium redistribution. The rod edge Zr increase is evidently due to the Soret term and temperature gradient. Then metallic fission gas release modeling is considered. Based on a GRSIS/FEAST model, the approach of generating fission gas in the fuel matrix is described. A sensitivity study on parameters is presented, including sodium bond & diffusion coefficient sensitivity along with dt sensitivity. Finally, results of some coupled simulations are shown, with ideas about future work.

  14. Epsilon Metal Waste Form for Immobilization of Noble Metals from Used Nuclear Fuel

    SciTech Connect

    Crum, Jarrod V.; Strachan, Denis M.; Rohatgi, Aashish; Zumhoff, Mac R.

    2013-10-01

    Epsilon metal (ε-metal), an alloy of Mo, Pd, Rh, Ru, and Tc, is being developed as a waste form to treat and immobilize the undissolved solids and dissolved noble metals from aqueous reprocessing of commercial used nuclear fuel. Epsilon metal is an attractive waste form for several reasons: increased durability relative to borosilicate glass, it can be fabricated without additives (100% waste loading), and in addition it also benefits borosilicate glass waste loading by eliminating noble metals from the glass and thus the processing problems related there insolubility in glass. This work focused on the processing aspects of the epsilon metal waste form development. Epsilon metal is comprised of refractory metals resulting in high reaction temperatures to form the alloy, expected to be 1500 - 2000°C making it a non-trivial phase to fabricate by traditional methods. Three commercially available advanced technologies were identified: spark-plasma sintering, microwave sintering, and hot isostatic pressing, and investigated as potential methods to fabricate this waste form. Results of these investigations are reported and compared in terms of bulk density, phase assemblage (X-ray diffraction and elemental analysis), and microstructure (scanning electron microscopy).

  15. Epsilon metal waste form for immobilization of noble metals from used nuclear fuel

    NASA Astrophysics Data System (ADS)

    Crum, Jarrod V.; Strachan, Denis; Rohatgi, Aashish; Zumhoff, Mac

    2013-10-01

    Epsilon metal (ɛ-metal), an alloy of Mo, Pd, Rh, Ru, and Tc, is being developed as a waste form to treat and immobilize the undissolved solids and dissolved noble metals from aqueous reprocessing of commercial used nuclear fuel. Epsilon metal is an attractive waste form for several reasons: increased durability relative to borosilicate glass, it can be fabricated without additives (100% waste loading), and in addition it also benefits borosilicate glass waste loading by eliminating noble metals from the glass, thus the processing problems related to their insolubility in glass. This work focused on the processing aspects of the epsilon metal waste form development. Epsilon metal is comprised of refractory metals resulting in high alloying temperatures, expected to be 1500-2000 °C, making it a non-trivial phase to fabricate by traditional methods. Three commercially available advanced technologies were identified: spark-plasma sintering, microwave sintering, and hot isostatic pressing, and investigated as potential methods to fabricate this waste form. Results of these investigations are reported and compared in terms of bulk density, phase assemblage (X-ray diffraction and elemental analysis), and microstructure (scanning electron microscopy).

  16. Process for the production of fuels and metal values

    SciTech Connect

    Audeh, C.A.

    1983-06-28

    A process for producing liquid fuels and for recovering metal values from crude petroleum by vis-breaking the reduced crude petroleum and dealkylating the vis-broken, reduced crude by treatment with an aromatic compound and an acidic transalkylation catalyst. The liquid product from the dealkylation step is separated and the residue fraction thermally processed with coal to solubilize the coal in the aromatic residue and demetallate the residue with the coal. The coal is partly liquefied in this step and the liquefaction products, together with liquids derived from the petroleum, may be hydrotreated prior to further processing e.g., in an fcc unit. The solid residue from this step may be treated to recover the metal values, especially nickel and vanadium.

  17. Metal sorbents for high temperature mercury capture from fuel gas

    SciTech Connect

    Poulston, S.; Granite, E.J.; Pennline, H.W.; Myers, C.R.; Stanko, D.P.; Hamilton, H.; Rowsell, L.; Smith, A.W.J.; Ilkenhans, T.; Chu, W.

    2007-09-01

    We have determined the Hg removal capacities of Pt and Pd supported on alumina at a range of different metal loadings from 2 to 9 wt% using Hg vapour in a simulated fuel gas feed. In the temperature range studied (204–388 °C) Pd proved far superior to Pt for Hg removal. The Hg removal capacity for both Pt and Pd increased with metal loading, though decreased with sorbent temperature. A shift in the 2{theta} position of the Pd XRD diffraction peak from 82.1 to 79.5 after Hg adsorption at 204 °C was consistent with the formation of a solid solution of Hg in Pd.

  18. Shales and swelling soils

    NASA Astrophysics Data System (ADS)

    Franklin, J. A.; Dimillio, A. F.; Strohm, W. E., Jr.; Vandre, B. C.; Anderson, L. R.

    The thirteen (13) papers in this report deal with the following areas: a shale rating system and tentative applications to shale performance; technical guidelines for the design and construction of shale embankments; stability of waste shale embankments; dynamic response of raw and stabilized Oklahoma shales; laboratory studies of the stabilization of nondurable shales; swelling shale and collapsing soil; development of a laboratory compaction degradation test for shales; soil section approach for evaluation of swelling potential soil moisture properties of subgrade soils; volume changes in compacted clays and shales on saturation; characterization of expansive soils; pavement roughness on expansive clays; and deep vertical fabric moisture barriers in swelling soils.

  19. Pyrometallurgical processing of Integral Fast Reactor metal fuels

    SciTech Connect

    Battles, J.E.; Miller, W.E.; Gay, E.C.

    1991-01-01

    The pyrometallurgical process for recycling spent metal fuels from the Integral Fast Reactor is now in an advanced state of development. This process involves electrorefining spent fuel with a cadmium anode, solid and liquid cathodes, and a molten salt electrolyte (LiCl-KCl) at 500{degrees}C. The initial process feasibility and flowsheet verification studies have been conducted in a laboratory-scale electrorefiner. Based on these studies, a dual cathode approach has been adopted, where uranium is recovered on a solid cathode mandrel and uranium-plutonium is recovered in a liquid cadmium cathode. Consolidation and purification (salt and cadmium removal) of uranium and uranium-plutonium products from the electrorefiner have been successful. The process is being developed with the aid of an engineering-scale electrorefiner, which has been successfully operated for more than three years. In this electrorefiner, uranium has been electrotransported from the cadmium anode to a solid cathode in 10 kg quantities. Also, anodic dissolution of 10 kg batches of chopped, simulated fuel (U--10% Zr) has been demonstrated. Development of the liquid cadmium cathode for recovering uranium-plutonium is under way.

  20. High-temperature compatibility between liquid metal as PWR fuel gap filler and stainless steel and high-density concrete

    NASA Astrophysics Data System (ADS)

    Wongsawaeng, Doonyapong; Jumpee, Chayanit; Jitpukdee, Manit

    2014-08-01

    In conventional nuclear fuel rods for light-water reactors, a helium-filled as-fabricated gap between the fuel and the cladding inner surface accommodates fuel swelling and cladding creep down. Because helium exhibits a very low thermal conductivity, it results in a large temperature rise in the gap. Liquid metal (LM; 1/3 weight portion each of lead, tin, and bismuth) has been proposed to be a gap filler because of its high thermal conductivity (∼100 times that of He), low melting point (∼100 °C), and lack of chemical reactivity with UO2 and water. With the presence of LM, the temperature drop across the gap is virtually eliminated and the fuel is operated at a lower temperature at the same power output, resulting in safer fuel, delayed fission gas release and prevention of massive secondary hydriding. During normal reactor operation, should an LM-bonded fuel rod failure occurs resulting in a discharge of liquid metal into the bottom of the reactor pressure vessel, it should not corrode stainless steel. An experiment was conducted to confirm that at 315 °C, LM in contact with 304 stainless steel in the PWR water chemistry environment for up to 30 days resulted in no observable corrosion. Moreover, during a hypothetical core-melt accident assuming that the liquid metal with elevated temperature between 1000 and 1600 °C is spread on a high-density concrete basement of the power plant, a small-scale experiment was performed to demonstrate that the LM-concrete interaction at 1000 °C for as long as 12 h resulted in no penetration. At 1200 °C for 5 h, the LM penetrated a distance of ∼1.3 cm, but the penetration appeared to stop. At 1400 °C the penetration rate was ∼0.7 cm/h. At 1600 °C, the penetration rate was ∼17 cm/h. No corrosion based on chemical reactions with high-density concrete occurred, and, hence, the only physical interaction between high-temperature LM and high-density concrete was from tiny cracks generated from thermal stress. Moreover

  1. The evaluation of the use of metal alloy fuels in pressurized water reactors. Final report

    SciTech Connect

    Lancaster, D.

    1992-10-26

    The use of metal alloy fuels in a PWR was investigated. It was found that it would be feasible and competitive to design PWRs with metal alloy fuels but that there seemed to be no significant benefits. The new technology would carry with it added economic uncertainty and since no large benefits were found it was determined that metal alloy fuels are not recommended. Initially, a benefit was found for metal alloy fuels but when the oxide core was equally optimized the benefit faded. On review of the optimization of the current generation of ``advanced reactors,`` it became clear that reactor design optimization has been under emphasized. Current ``advanced reactors`` are severely constrained. The AP-600 required the use of a fuel design from the 1970`s. In order to find the best metal alloy fuel design, core optimization became a central effort. This work is ongoing.

  2. Thermal analysis for fuel handling system for sodium cooled reactor considering minor actinide-bearing metal fuel.

    SciTech Connect

    Chikazawa, Y.; Grandy, C.; Nuclear Engineering Division

    2009-03-01

    The Advanced Burner Reactor (ABR) is one of the components of the Global Nuclear Energy Partnership (GNEP) used to close the fuel cycle. ABR is a sodium-cooled fast reactor that is used to consume transuranic elements resulting from the reprocessing of light water reactor spent nuclear fuel. ABR-1000 [1000 MW(thermal)] is a fast reactor concept created at Argonne National Laboratory to be used as a reference concept for various future trade-offs. ABR-1000 meets the GNEP goals although it uses what is considered base sodium fast reactor technology for its systems and components. One of the considerations of any fast reactor plant concept is the ability to perform fuel-handling operations with new and spent fast reactor fuel. The transmutation fuel proposed as the ABR fuel has a very little experience base, and thus, this paper investigates a fuel-handling concept and potential issues of handling fast reactor fuel containing minor actinides. In this study, two thermal analyses supporting a conceptual design study on the ABR-1000 fuel-handling system were carried out. One analysis investigated passive dry spent fuel storage, and the other analysis investigated a fresh fuel shipping cask. Passive dry storage can be made suitable for the ABR-1000 spent fuel storage with sodium-bonded metal fuel. The thermal analysis shows that spent fast reactor fuel with a decay heat of 2 kW or less can be stored passively in a helium atmosphere. The 2-kW value seems to be a reasonable and practical level, and a combination of reasonably-sized in-sodium storage followed by passive dry storage could be a candidate for spent fuel storage for the next-generation sodium-cooled reactor with sodium-bonded metal fuel. Requirements for the shipping casks for minor actinide-bearing fuel with a high decay heat level are also discussed in this paper. The shipping cask for fresh sodium-cooled-reactor fuel should be a dry type to reduce the reaction between residual moisture on fresh fuel and the

  3. Platinum redispersion on metal oxides in low temperature fuel cells.

    PubMed

    Tripković, Vladimir; Cerri, Isotta; Nagami, Tetsuo; Bligaard, Thomas; Rossmeisl, Jan

    2013-03-01

    We have analyzed the aptitude of several metal oxide supports (TiO(2), SnO(2), NbO(2), ZrO(2), SiO(2), Ta(2)O(5) and Nb(2)O(5)) to redisperse platinum under electrochemical conditions pertinent to the Proton Exchange Membrane Fuel Cell (PEMFC) cathode. The redispersion on oxide supports in air has been studied in detail; however, due to different operating conditions it is not straightforward to link the chemical and the electrochemical environment. The largest differences reflect in (1) the oxidation state of the surface (the oxygen species coverage), (2) temperature and (3) the possibility of platinum dissolution at high potentials and the interference of redispersion with normal working potential of the PEMFC cathode. We have calculated the PtO(x) (x = 0, 1, 2) adsorption energies on different metal oxides' surface terminations as well as inside the metal oxides' bulk, and we have concluded that NbO(2) might be a good support for platinum redispersion at PEMFC cathodes. PMID:23358311

  4. Stem drive oil recovery method utilizing a downhole steam generator and anti clay-swelling agent

    SciTech Connect

    Hopkins, D. N.; Snavely, E. S.

    1985-06-11

    Viscous oil is recovered from a subterranean, viscous oil-containing formation by a steam flooding technique wherein steam is generated in a downhole steam generator located in an injection well by spontaneous combustion of a pressurized mixture of a water-soluble fuel such as sugars and alcohols dissolved in water or a stable hydrocarbon fuel-in-water emulsion containing an anti clay-swelling agent and substantially pure oxygen. The generated mixture of steam and combustion gases pass through the formation, displacing oil and reducing the oil's viscosity and the mobilized oil is produced from the formation via a spaced-apart production well. Suitable anti clay-swelling agents include metal halide salts and diammonium phosphate.

  5. Swelling of U(Mo)–Al(Si) dispersion fuel under irradiation – Non-destructive analyses of the LEONIDAS E-FUTURE plates

    SciTech Connect

    S. Van den Berghe; Y. Parthoens; F. Charollais; Y. S. Kim; A. Leenaers; E. Koonen; V. Kuzminov; P. Lemoine; C. Jarousse; H. Guyon; D. Wachs; D. Keiser, Jr.; A. Robinson; J. Stevens; G. Hofman

    2012-11-01

    In the framework of the elimination of High-Enriched Uranium (HEU) from the civil circuit, the search for an appropriate fuel to replace the high-enriched research reactor fuel in those reactors that currently still require it for their operation has led to the development of a U–7 wt.%Mo alloy based dispersion fuel with an Al–Si matrix. The European LEONIDAS program, joining SCK-CEN, ILL, CEA and AREVA-CERCA, is aimed at the qualification of such a fuel for the use in high power conditions. The first experiment of the program, designated E-FUTURE, was performed to select the appropriate matrix Si concentration and fuel plate post-production heat treatment parameters for further qualification. It consisted of the irradiation of four distinct (4% and 6% Si, 3 different heat treatments) full size, flat fuel plates in the BR2 reactor. The irradiation conditions were relatively severe: 470 W/cm2 peak BOL power, with an approximate 70% 235U peak burnup.

  6. Swelling of U(Mo)-Al(Si) dispersion fuel under irradiation - Non-destructive analyses of the LEONIDAS E-FUTURE plates

    NASA Astrophysics Data System (ADS)

    Van den Berghe, S.; Parthoens, Y.; Charollais, F.; Kim, Y. S.; Leenaers, A.; Koonen, E.; Kuzminov, V.; Lemoine, P.; Jarousse, C.; Guyon, H.; Wachs, D.; Keiser, D., Jr.; Robinson, A.; Stevens, J.; Hofman, G.

    2012-11-01

    In the framework of the elimination of High-Enriched Uranium (HEU) from the civil circuit, the search for an appropriate fuel to replace the high-enriched research reactor fuel in those reactors that currently still require it for their operation has led to the development of a U-7 wt.%Mo alloy based dispersion fuel with an Al-Si matrix. The European LEONIDAS program, joining SCK•CEN, ILL, CEA and AREVA-CERCA, is aimed at the qualification of such a fuel for the use in high power conditions. The first experiment of the program, designated E-FUTURE, was performed to select the appropriate matrix Si concentration and fuel plate post-production heat treatment parameters for further qualification. It consisted of the irradiation of four distinct (4% and 6% Si, 3 different heat treatments) full size, flat fuel plates in the BR2 reactor. The irradiation conditions were relatively severe: 470 W/cm2 peak BOL power, with a ˜70% 235U peak burnup.

  7. N-Reactor (U-metal) Fuel Characteristics for Disposal Criticality Analysis

    SciTech Connect

    Taylor, Larry Lorin

    2000-05-01

    DOE-owned spent nuclear fuels encompass many fuel types. In an effort to facilitate criticality analysis for these various fuel types, they were categorized into nine characteristic fuel groups with emphasis on fuel matrix composition. Out of each fuel group, a representative fuel type was chosen for analysis as a bounding case within that fuel group. Generally, burnup data, fissile enrichments, and total fuel and fissile mass govern the selection of the representative or candidate fuel within that group. Additionally, the criticality analysis will also require data to support design of the canister internals, thermal, and radiation shielding. The purpose of this report is to consolidate and provide in a concise format, material and information/data needed to perform supporting analyses to qualify N-Reactor fuels for acceptance into the designated repository. The N Reactor fuels incorporate zirconium cladding and uranium metal with unique fabrication details in terms of physical size, and method of construction. The fuel construction and post-irradiation handling have created attendant issues relative to cladding failure in the underwater storage environment. These fuels were comprised of low-enriched metal (0.947 to 1.25 wt% 235U) that were originally intended to generate weapons-grade plutonium for national defense. Modifications in subsequent fuel design and changes in the mode of reactor operation in later years were focused more toward power production.

  8. Intermittent facial swelling

    PubMed Central

    Pope, Charlie; Gopala Pillai, Suresh Kumar

    2014-01-01

    Intermittent facial swelling is an unusual presentation in the emergency department. The differential diagnosis may range from a variety of causes. Most common differential diagnosis is angio-oedema. However, more serious presentations such as superior venacaval obstruction must not be ignored. This case report presents a patient who was investigated in the hospital for 2 weeks (2 admissions) with intermittent facial swelling. He presented to the emergency department (3rd admission) and was diagnosed to have superior venacaval obstruction secondary to metastatic bronchogenic carcinoma. He underwent emergency endovascular stenting; however, he died within a few weeks. PMID:25326556

  9. Approaches to mitigate metal catalyst deactivation in solid oxide fuel cell (SOFC) fuel electrodes

    NASA Astrophysics Data System (ADS)

    Adijanto, Lawrence

    While Ni/YSZ cermets have been used successfully in SOFCs, they also have several limitations, thus motivating the use of highly conductive ceramics to replace the Ni components in SOFC anodes. Ceramic electrodes are promising for use in SOFC anodes because they are expected to be less susceptible to sintering and coking, be redox stable, and be more tolerant of impurities like sulfur. In this thesis, for catalytic studies, the infiltration procedure has been used to form composites which have greatly simplified the search for the best ceramics for anode applications. In the development of ceramic fuel electrodes for SOFC, high performance can only be achieved when a transition metal catalyst is added. Because of the high operating temperatures, deactivation of the metal catalyst by sintering and/or coking is a severe problem. In this thesis, two approaches aimed at mitigating metal catalyst deactivation which was achieved by: 1) designing a catalyst that is resistant to coking and sintering and 2) developing a new method for catalyst deposition, will be presented. The first approach involved synthesizing a self-regenerating, "smart" catalyst, in which Co, Cu, or Ni were inserted into the B-site of a perovskite oxide under oxidizing conditions and then brought back to the surface under reducing conditions. This restores lost surface area of sintered metal particles through an oxidation/reduction cycle. Results will be shown for each of the metals, as well as for Cu-Co mixed metal systems, which are found to exhibit good tolerance to carbon deposition and interesting catalytic properties. The second strategy involves depositing novel Pd CeO2 core-shell nanostructure catalysts onto a substrate surface which had been chemically modified to anchor the nanoparticles. The catalyst deposited onto the chemically modified, hydrophobic surface is shown to be uniform and well dispersed, and exhibit excellent thermal stability to temperatures as high as 1373 K. Similar metal

  10. Thermochemical Processing of Radioactive Waste Using Powder Metal Fuels

    SciTech Connect

    Ojovan, M. I.; Sobolev, I. A.; Dmitriev, S. A.; Panteleev, V. I.; Karlina, O. K.; Klimov. V. L.

    2003-02-25

    Problematic radioactive wastes were generated during various activities of both industrial facilities and research institutions usually in relative small amounts. These can be spent ion exchange resins, inorganic absorbents, wastes from research nuclear reactors, irradiated graphite, mixed, organic or chlorine-containing radioactive waste, contaminated soils, un-burnable heavily surface-contaminated materials, etc. Conventional treatment methods encounter serious problems concerning processing efficiency of such waste, e.g. complete destruction of organic molecules and avoiding of possible emissions of radionuclides, heavy metals and chemically hazardous species. Some contaminations cannot be removed from surface using common decontamination methods. Conditioning of ash residues obtained after treatment of solid radioactive waste including ashes received from treating problematic wastes also is a complicated task. Moreover due to relative small volume of specific type radioactive waste the development of target treatment procedures and facilities to conduct technological processes and their deployment could be economically unexpedient and ecologically no justified. Thermochemical processing technologies are used for treating and conditioning problematic radioactive wastes. The thermochemical processing uses powdered metal fuels (PMF) that are specifically formulated for the waste composition and react chemically with the waste components. The composition of the PMF is designed in such a way as to minimize the release of hazardous components and radionuclides in the off gas and to confine the contaminants in the ash residue. The thermochemical procedures allow decomposition of organic matter and capturing hazardous radionuclides and chemical species simultaneously. A significant advantage of thermochemical processing is its autonomy. Thermochemical treatment technologies use the energy of exothermic reactions in the mixture of radioactive or hazardous waste with PMF

  11. Hotspot swells revisited

    NASA Astrophysics Data System (ADS)

    King, Scott D.; Adam, Claudia

    2014-10-01

    The first attempts to quantify the width and height of hotspot swells were made more than 30 years ago. Since that time, topography, ocean-floor age, and sediment thickness datasets have improved considerably. Swell heights and widths have been used to estimate the heat flow from the core-mantle boundary, constrain numerical models of plumes, and as an indicator of the origin of hotspots. In this paper, we repeat the analysis of swell geometry and buoyancy flux for 54 hotspots, including the 37 considered by Sleep (1990) and the 49 considered by Courtillot et al. (2003), using the latest and most accurate data. We are able to calculate swell geometry for a number of hotspots that Sleep was only able to estimate by comparison with other swells. We find that in spite of the increased resolution in global bathymetry models there is significant uncertainty in our calculation of buoyancy fluxes due to differences in our measurement of the swells’ width and height, the integration method (volume integration or cross-sectional area), and the variations of the plate velocities between HS2-Nuvel1a (Gripp and Gordon, 1990) and HS3-Nuvel1a (Gripp and Gordon, 2002). We also note that the buoyancy flux for Pacific hotspots is in general larger than for Eurasian, North American, African and Antarctic hotspots. Considering that buoyancy flux is linearly related to plate velocity, we speculate that either the calculation of buoyancy flux using plate velocity over-estimates the actual vertical flow of material from the deep mantle or that convection in the Pacific hemisphere is more vigorous than the Atlantic hemisphere.

  12. Degradation mechanisms and mitigation strategies of metal cations in recycled fuel for direct methanol fuel cell membrane electrode assembly

    NASA Astrophysics Data System (ADS)

    Yang, Min-Jee; Park, Ka-Young; Kim, Ki-Beum; Cho, Hyejung; Choi, Hanshin; Park, Jun-Young

    2013-11-01

    Some metal contaminants, such as Al3+, Ni+2, Fe2+ and Cr3+, are produced during reactions in heat exchangers, stacks, and other fuel/water management system components. Due to the gradual build-up of these contaminants generated in the system, direct methanol fuel cell (DMFC) membrane electrode assemblies (MEAs) deteriorate steadily with increasing operation time. Hence, this study systematically investigates the effects of metal cations by supplying various concentrations of metal solutions to the fuel stream at constant-current densities, with the aim of understanding the mechanism and influence of metal contamination on a DMFC MEA. Various electrochemical diagnostic techniques are used to determine the main cause of MEA degradation, including electrochemical impedance spectroscopy, electrode polarization, and methanol stripping voltammetry. In addition, the critical concentration of metal cations in methanol fuel is investigated for high DMFC MEA stability. Further, various novel methods for mitigating the influence of the metal contaminants on the performance of a DMFC are suggested and verified.

  13. Alloy waste forms for metal fission products and actinides isolated by spent nuclear fuel treatment

    SciTech Connect

    McDeavitt, S.M.; Abraham, D.P.; Keiser, D.D. Jr.; Park, J.Y.

    1996-10-01

    Waste form alloys are being developed at Argonne National Laboratory for the disposal of remnant metallic wastes from an electrometallurgical process developed to treat spent nuclear fuel. This metal waste form consists of the fuel cladding (stainless steel or Zircaloy), noble metal fission products (e.g., Ru, Pd, Mo and Tc), and other metallic wastes. The main constituents of the metal waste stream are the cladding hulls (85 to 90 wt%); using the hulls as the dominant alloying component minimizes the overall waste volume as compared to vitrification or metal encapsulation. Two nominal compositions for the waste form are being developed: (1) stainless steel-15 wt% zirconium for stainless steel-clad fuels and (2) zirconium-8 wt% stainless steel for Zircaloy-clad fuels. The noble metal fission products are the primary source of radiation in the metal waste form. However, inclusion of actinides in the metal waste form is being investigated as an option for interim or ultimate storage. Simulated waste form alloys were prepared and analyzed to determine the baseline alloy microstructures and the microstructural distribution of noble metals and actinides. Corrosion tests of the metal waste form alloys indicate that they are highly resistant to corrosion.

  14. Measuring the noble metal and iodine composition of extracted noble metal phase from spent nuclear fuel using instrumental neutron activation analysis.

    PubMed

    Palomares, R I; Dayman, K J; Landsberger, S; Biegalski, S R; Soderquist, C Z; Casella, A J; Brady Raap, M C; Schwantes, J M

    2015-04-01

    Masses of noble metal and iodine nuclides in the metallic noble metal phase extracted from spent fuel are measured using instrumental neutron activation analysis. Nuclide presence is predicted using fission yield analysis, and radionuclides are identified and the masses quantified using neutron activation analysis. The nuclide compositions of noble metal phase derived from two dissolution methods, UO2 fuel dissolved in nitric acid and UO2 fuel dissolved in ammonium-carbonate and hydrogen-peroxide solution, are compared. PMID:25644079

  15. Actinides recovery from irradiated metallic fuel in LiCl-KCl melts

    NASA Astrophysics Data System (ADS)

    Murakami, T.; Rodrigues, A.; Ougier, M.; Iizuka, M.; Tsukada, T.; Glatz, J.-P.

    2015-11-01

    Electrorefining of irradiated metallic fuels was successfully demonstrated: Actinides (U, Pu, Np, Am and Cm) in the fuels were dissolved in LiCl-KCl melts with high dissolution ratios, while U was selectively deposited on a solid cathode and the simultaneous recovery of actinides in a liquid Cd cathode was confirmed. The behavior of actinides, the fuel matrix stabilizer Zr and fission products such as lanthanide, alkaline, alkaline earth and noble metal, at the electrorefining is discussed based on the ICP-MS analysis of the samples taken from molten salt electrolyte, anode fuel residues and cathode deposits.

  16. Emission FTIR analyses of thin microscopic patches of jet fuel residue deposited on heated metal surface

    NASA Technical Reports Server (NTRS)

    Lauer, J. L.; Vogel, P.

    1984-01-01

    Deposits laid down in patches on metal strips in a high pressure/high temperature fuel system simulator operated with aerated fuel at varying flow rates were analyzed by emission FTIR in terms of functional groups. Significant differences were found in the spectra and amounts of deposits derived from fuels to which small concentrations of oxygen-, nitrogen-, or sulfur-containing heterocyclics or metal naphthenates were added. The spectra of deposits generated on strips by heating fuels and air in a closed container were very different from those of the flowing fluid deposits. One such closed-container dodecane deposit on silver gave a strong surface-enhanced Raman spectrum.

  17. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1991-08-01

    Research continued on the determination of pore size and number distribution changes after swelling the coal samples with various solvents. A paper has just been submitted to the journal Fuel on the Low temperature Swelling of Argonne Premium Coal samples using solvents of varying polarity. The variation in the shape of the pore was followed as a function of temperature and swelling solvent polarity. This change in pore structure was attributed to break-up of the hydrogen bonding network in coal by polar solvents. The modification in pore shape from spherical to cylindrical was attributed to anisotropy in hydrogen bond densities. A copy of this paper has been attached to this report. Wojciech Sady has determine the structural changes in the pores that occur when APCS coal is dehydrated prior to swelling with polar solvents. These changes are different from those that occur in the absence of prior dehydration. He has also completed a study on the variation in the hydrogen bonding character of the pore wall as the coals are swelled with various polar solvents. A statistical analysis of the data is currently underway to determine important trends in his data. 9 refs.

  18. Lanthanides in Metallic Nuclear Fuels: Their Behavior and Methods for Their Control

    SciTech Connect

    Robert D. Mariani; Douglas L. Porter; Thomas P. O'Holleran; Steven L. Hayes; J. Rory Kennedy

    2011-12-01

    The thermodynamic and experimental basis is given for using dopant additives to bind lanthanides as intermetallic compounds in metallic nuclear fuels. Lanthanide fission products are a major factor in limiting the lifetime of the fuel, because they migrate to the fuel slug peripheral surface where they participate in fuel-cladding chemical interactions (FCCI) with the steel cladding. Lanthanide carryover in recycled metal fuels can accelerate FCCI, as recycled lanthanides would likely segregate from the fuel phase, putting the lanthanides in prompt contact with the cladding. In out-of-pile tests we examined the use of Pd for binding the lanthanides, with Pd selected because of its known metallurgical properties in fuel related systems and because of its known behavior in irradiated EBR-II fuels. Initial results confirmed that palladium may be expected to mitigate FCCI arising from lanthanides, and it has been recommended for in-pile tests. We also evaluated transport phenomena responsible for lanthanide migration, and identified liquid-like behaviors as being dominant. Liquid-like behaviors include transport with liquid metals, liquid metal solutions, and rapid surface transport of alloys/metals near their melting temperatures. The analysis led to establishing general criteria for selecting alternate dopant additives, and identifying Sn, Sb, and Te as alternates for further testing.

  19. Mitosis is swell.

    PubMed

    Zatulovskiy, Evgeny; Skotheim, Jan M

    2015-11-23

    Cell volume and dry mass are typically correlated. However, in this issue, Zlotek-Zlotkiewicz et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201505056) and Son et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201505058) use new live-cell techniques to show that entry to mitosis coincides with rapid cell swelling, which is reversed before division.

  20. Mitosis is swell

    PubMed Central

    Zatulovskiy, Evgeny

    2015-01-01

    Cell volume and dry mass are typically correlated. However, in this issue, Zlotek-Zlotkiewicz et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201505056) and Son et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201505058) use new live-cell techniques to show that entry to mitosis coincides with rapid cell swelling, which is reversed before division. PMID:26598610

  1. Temperature and Burnup Correlated FCCI in U-10Zr Metallic Fuel

    SciTech Connect

    William J. Carmack

    2012-05-01

    Metallic fuels are proposed for use in advanced sodium cooled fast reactors. The experience basis for metallic fuels is extensive and includes development and qualification of fuels for the Experimental Breeder Reactor I, the Experimental Breeder Reactor II, FERMI-I, and the Fast Flux Test Facility (FFTF) reactors. Metallic fuels provide a number of advantages over other fuel types in terms of fabricability, performance, recyclability, and safety. Key to the performance of all nuclear fuel systems is the resistance to “breach” and subsequent release of fission products and fuel constituents to the primary coolant system of the nuclear power plant. In metallic fuel, the experience is that significant fuel-cladding chemical (FCCI) interaction occurs and becomes prevalent at high power-high temperature operation and ultimately leads to fuel pin breach and failure. Empirical relationships for metallic fuel pin failure have been developed from a large body of in-pile and out of pile research, development, and experimentation. It has been found that significant in-pile acceleration of the FCCI rate is experienced over similar condition out-of-pile experiments. The study of FCCI in metallic fuels has led to the quantification of in-pile failure rates to establish an empirical time and temperature dependent failure limit for fuel elements. Up until now the understanding of FCCI layer formation has been limited to data generated in EBR-II experiments. This dissertation provides new FCCI data extracted from the MFF-series of metallic fuel irradiations performed in the FFTF. These fuel assemblies contain valuable information on the formation of FCCI in metallic fuels at a variety of temperature and burnup conditions and in fuel with axial fuel height three times longer than EBR-II experiments. The longer fuel column in the FFTF and the fuel pins examined have significantly different flux, power, temperature, and FCCI profiles than that found in similar tests conducted in

  2. SUB-LEU-METAL-THERM-001 SUBCRITICAL MEASUREMENTS OF LOW ENRICHED TUBULAR URANIUM METAL FUEL ELEMENTS BEFORE & AFTER IRRADIATION

    SciTech Connect

    SCHWINKENDORF, K.N.

    2006-05-12

    With the shutdown of the Hanford PUREX (Plutonium-Uranium Extraction Plant) reprocessing plant in the 1970s, adequate storage capacity for spent Hanford N Reactor fuel elements in the K and N Reactor pools became a concern. To maximize space utilization in the pools, accounting for fuel burnup was considered. Calculations indicated that at typical fuel exposures for N Reactor, the spent-fuel critical mass would be twice the critical mass for green fuel. A decision was reached to test the calculational result with a definitive experiment. If the results proved positive, storage capacity could be increased and N Reactor operation could be prolonged. An experiment to be conducted in the N Reactor spent-fuel storage pool was designed and assembled and the services of the Battelle Northwest Laboratories (BNWL) (now Pacific Northwest National Laboratory [PNNL]) critical mass laboratory were procured for the measurements. The experiments were performed in April 1975 in the Hanford N Reactor fuel storage pool. The fuel elements were MKIA fuel assemblies, comprising two concentric tubes of low-enriched metallic uranium. Two separate sets of measurements were performed: one with ''green'' (fresh) fuel and one with spent fuel. Both the green and spent fuel, were measured in the same geometry. The spent-fuel MKIA assemblies had an average burnup of 2865 MWd (megawatt days)/t. A constraint was imposed restricting the measurements to a subcritical limit of k{sub eff} = 0.97. Subcritical count rate data was obtained with pulsed-neutron and approach-to-critical measurements. Ten (10) configurations with green fuel and nine (9) configurations with spent fuel are described and evaluated. Of these, 3 green fuel and 4 spent fuel loading configurations were considered to serve as benchmark models. However, shortcomings in experimental data failed to meet the high standards for a benchmark problem. Nevertheless, the data provided by these subcritical measurements can supply useful

  3. Pumped lithium loop test to evaluate advanced refractory metal alloys and simulated nuclear fuel elements

    NASA Technical Reports Server (NTRS)

    Brandenburf, G. P.; Hoffman, E. E.; Smith, J. P.

    1974-01-01

    The performance was determined of refractory metal alloys and uranium nitride fuel element specimens in flowing 1900F (1083C) lithium. The results demonstrate the suitability of the selected materials to perform satisfactorily from a chemical compatibility standpoint.

  4. Dimensional, microstructural and compositional stability of metal fuels. Final performance report

    SciTech Connect

    Solomon, A.A.; Dayananda, M.A.

    1993-03-15

    The projects undertaken were to address two areas of concern for metal-fueled fast reactors: metallurgical compatibility of fuel and its fission products with the stainless steel cladding, and effects of porosity development in the fuel on fuel/cladding interactions and on sodium penetration in fuel. The following studies are reported on extensively in appendices: hot isostatic pressing of U-10Zr by coupled boundary diffusion/power law creep cavitation, liquid Na intrusion into porous U-10Zr fuel alloy by differential capillarity, interdiffusion between U-Zr fuel and selected Fe-Ni-Cr alloys, interdiffusion between U-Zr fuel vs selected cladding steels, and interdiffusion of Ce in Fe-base alloys with Ni or Cr.

  5. The performance of 3500 MWth homogeneous and heterogeneous metal fueled core designs

    SciTech Connect

    Turski, R.; Yang, Shi-tien

    1987-11-01

    Performance parameters are calculated for a representative 3500 MWth homogeneous and a heterogeneous metal fueled reactor design. The equilibrium cycle neutronic characteristics, safety coefficients, control system requirements, and control rod worths are evaluated. The thermal-hydraulic characteristics for both configurations are also compared. The heavy metal fuel loading requirements and neutronic performance characteristics are also evaluated for the uranium startup option. 14 refs., 14 figs., 20 tabs.

  6. High dose effects in neutron irradiated face-centered cubic metals

    SciTech Connect

    Garner, F.A.; Toloczko, M.B.

    1993-06-01

    During neutron irradiation, most face-centered cubic metals and alloys develop saturation or quasi-steady state microstructures. This, in turn, leads to saturation levels in mechanical properties and quasi-steady state rates of swelling and creep deformation. Swelling initially plays only a small role in determining these saturation states, but as swelling rises to higher levels, it exerts strong feedback on the microstructure and its response to environmental variables. The influence of swelling, either directly or indirectly via second order mechanisms, such as elemental segregation to void surfaces, eventually causes major changes, not only in irradiation creep and mechanical properties, but also on swelling itself. The feedback effects of swelling on irradiation creep are particularly complex and lead to problems in applying creep data derived from highly pressurized creep tubes to low stress situations, such as fuel pins in liquid metal reactors.

  7. Fate of Noble Metals during the Pyroprocessing of Spent Nuclear Fuel

    SciTech Connect

    B.R. Westphal; D. Vaden; S.X. Li; G.L. Fredrickson; R.D. Mariani

    2009-09-01

    During the pyroprocessing of spent nuclear fuel by electrochemical techniques, fission products are separated as the fuel is oxidized at the anode and refined uranium is deposited at the cathode. Those fission products that are oxidized into the molten salt electrolyte are considered active metals while those that do not react are considered noble metals. The primary noble metals encountered during pyroprocessing are molybdenum, zirconium, ruthenium, rhodium, palladium, and technetium. Pyroprocessing of spent fuel to date has involved two distinctly different electrorefiner designs, in particular the anode to cathode configuration. For one electrorefiner, the anode and cathode collector are horizontally displaced such that uranium is transported across the electrolyte medium. As expected, the noble metal removal from the uranium during refining is very high, typically in excess of 99%. For the other electrorefiner, the anode and cathode collector are vertically collocated to maximize uranium throughput. This arrangement results in significantly less noble metals removal from the uranium during refining, typically no better than 20%. In addition to electrorefiner design, operating parameters can also influence the retention of noble metals, albeit at the cost of uranium recovery. Experiments performed to date have shown that as much as 100% of the noble metals can be retained by the cladding hulls while affecting the uranium recovery by only 6%. However, it is likely that commercial pyroprocessing of spent fuel will require the uranium recovery to be much closer to 100%. The above mentioned design and operational issues will likely be driven by the effects of noble metal contamination on fuel fabrication and performance. These effects will be presented in terms of thermal properties (expansion, conductivity, and fusion) and radioactivity considerations. Ultimately, the incorporation of minor amounts of noble metals from pyroprocessing into fast reactor metallic fuel

  8. Heavy metal inventory and fuel sustainability of recycling TRU in FBR design

    NASA Astrophysics Data System (ADS)

    Permana, Sidik; Suzuki, Mitsutoshi; Su'ud, Zaki

    2012-06-01

    Nuclear fuel materials from spent fuel of light water reactors have a potential to be used for destructive devices with very huge energy release or in the same time, it can be utilized as a peaceful energy or civil applications, for generating electricity, desalination of water, medical application and others applications. Several research activities showed some recycled spent fuel can be used as additional fuel loading for increasing fuel breeding capability as well as improving intrinsic aspect of nuclear non-proliferation. The present investigation intends to evaluate the composition of heavy metals inventories and fuel breeding capability in the FBR design based on the loaded fuel of light water reactor (LWR) spent fuel (SF) of 33 GWd/t with 5 years cooling time by adopting depletion code of ORIGEN. Whole core analysis of FBR design is performed by adopting and coupling codes such as SLAROM code, JOINT and CITATION codes. Nuclear data library, JFS-3-J-3.2R which is based on the JENDL 3.2 has been used for nuclear data analysis. JSFR design is the basis design reference which basically adopted 800 days cycle length for 4 batches system. Higher inventories of plutonium of MOX fuel and TRU fuel types at equilibrium composition than initial composition have been shown. Minor actinide (MA) inventory compositions obtain a different inventory trends at equilibrium composition for both fuel types. Higher Inventory of MA is obtained by MOX fuel and less MA inventory for TRU fuel at equilibrium composition than initial composition. Some different MA inventories can be estimated from the different inventory trend of americium (Am). Higher americium inventory for MOX fuel and less americium inventory for TRU fuel at equilibrium condition. Breeding ratio of TRU fuel is relatively higher compared with MOX fuel type. It can be estimated from relatively higher production of Pu-238 (through converted MA) in TRU fuel, and Pu-238 converts through neutron capture to produce Pu-239

  9. Heavy metal inventory and fuel sustainability of recycling TRU in FBR design

    SciTech Connect

    Permana, Sidik; Suzuki, Mitsutoshi; Su'ud, Zaki

    2012-06-06

    Nuclear fuel materials from spent fuel of light water reactors have a potential to be used for destructive devices with very huge energy release or in the same time, it can be utilized as a peaceful energy or civil applications, for generating electricity, desalination of water, medical application and others applications. Several research activities showed some recycled spent fuel can be used as additional fuel loading for increasing fuel breeding capability as well as improving intrinsic aspect of nuclear non-proliferation. The present investigation intends to evaluate the composition of heavy metals inventories and fuel breeding capability in the FBR design based on the loaded fuel of light water reactor (LWR) spent fuel (SF) of 33 GWd/t with 5 years cooling time by adopting depletion code of ORIGEN. Whole core analysis of FBR design is performed by adopting and coupling codes such as SLAROM code, JOINT and CITATION codes. Nuclear data library, JFS-3-J-3.2R which is based on the JENDL 3.2 has been used for nuclear data analysis. JSFR design is the basis design reference which basically adopted 800 days cycle length for 4 batches system. Higher inventories of plutonium of MOX fuel and TRU fuel types at equilibrium composition than initial composition have been shown. Minor actinide (MA) inventory compositions obtain a different inventory trends at equilibrium composition for both fuel types. Higher Inventory of MA is obtained by MOX fuel and less MA inventory for TRU fuel at equilibrium composition than initial composition. Some different MA inventories can be estimated from the different inventory trend of americium (Am). Higher americium inventory for MOX fuel and less americium inventory for TRU fuel at equilibrium condition. Breeding ratio of TRU fuel is relatively higher compared with MOX fuel type. It can be estimated from relatively higher production of Pu-238 (through converted MA) in TRU fuel, and Pu-238 converts through neutron capture to produce Pu-239

  10. Simplified process for leaching precious metals from fuel cell membrane electrode assemblies

    DOEpatents

    Shore, Lawrence; Matlin, Ramail

    2009-12-22

    The membrane electrode assemblies of fuel cells are recycled to recover the catalyst precious metals from the assemblies. The assemblies are cryogenically embrittled and pulverized to form a powder. The pulverized assemblies are then mixed with a surfactant to form a paste which is contacted with an acid solution to leach precious metals from the pulverized membranes.

  11. A direct borohydride fuel cell with a polymer fiber membrane and non-noble metal catalysts.

    PubMed

    Yang, Xiaodong; Liu, Yongning; Li, Sai; Wei, Xiaozhu; Wang, Li; Chen, Yuanzhen

    2012-01-01

    Polymer electrolyte membranes (PEM) and Pt-based catalysts are two crucial components which determine the properties and price of fuel cells. Even though, PEM faces problem of fuel crossover in liquid fuel cells such as direct methanol fuel cell (DMFC) and direct borohydride fuel cell (DBFC), which lowers power output greatly. Here, we report a DBFC in which a polymer fiber membrane (PFM) was used, and metal oxides, such as LaNiO₃ and MnO₂, were used as cathode catalysts, meanwhile CoO was used as anode catalyst. Peak power density of 663 mW·cm⁻² has been achieved at 65°C, which increases by a factor of 1.7-3.7 compared with classic DBFCs. This fuel cell structure can also be extended to other liquid fuel cells, such as DMFC.

  12. A direct borohydride fuel cell with a polymer fiber membrane and non-noble metal catalysts

    PubMed Central

    Yang, Xiaodong; Liu, Yongning; Li, Sai; Wei, Xiaozhu; Wang, Li; Chen, Yuanzhen

    2012-01-01

    Polymer electrolyte membranes (PEM) and Pt-based catalysts are two crucial components which determine the properties and price of fuel cells. Even though, PEM faces problem of fuel crossover in liquid fuel cells such as direct methanol fuel cell (DMFC) and direct borohydride fuel cell (DBFC), which lowers power output greatly. Here, we report a DBFC in which a polymer fiber membrane (PFM) was used, and metal oxides, such as LaNiO3 and MnO2, were used as cathode catalysts, meanwhile CoO was used as anode catalyst. Peak power density of 663 mW·cm−2 has been achieved at 65°C, which increases by a factor of 1.7–3.7 compared with classic DBFCs. This fuel cell structure can also be extended to other liquid fuel cells, such as DMFC. PMID:22880160

  13. Method for preparing metal powder, device for preparing metal powder, method for processing spent nuclear fuel

    DOEpatents

    Park, Jong-Hee

    2011-11-29

    A method for producing metal powder is provided the comprising supplying a molten bath containing a reducing agent, contacting a metal oxide with the molten bath for a time and at a temperature sufficient to reduce the metal in the metal oxide to elemental metal and produce free oxygen; and isolating the elemental metal from the molten bath.

  14. Fuel Cycle System Analysis Implications of Sodium-Cooled Metal-Fueled Fast Reactor Transuranic Conversion Ratio

    SciTech Connect

    Steven J. Piet; Edward A. Hoffman; Samuel E. Bays; Gretchen E. Matthern; Jacob J. Jacobson; Ryan Clement; David W. Gerts

    2013-03-01

    If advanced fuel cycles are to include a large number of fast reactors (FRs), what should be the transuranic (TRU) conversion ratio (CR)? The nuclear energy era started with the assumption that they should be breeder reactors (CR > 1), but the full range of possible CRs eventually received attention. For example, during the recent U.S. Global Nuclear Energy Partnership program, the proposal was burner reactors (CR < 1). Yet, more recently, Massachusetts Institute of Technology's "Future of the Nuclear Fuel Cycle" proposed CR [approximately] 1. Meanwhile, the French company EDF remains focused on breeders. At least one of the reasons for the differences of approach is different fuel cycle objectives. To clarify matters, this paper analyzes the impact of TRU CR on many parameters relevant to fuel cycle systems and therefore spans a broad range of topic areas. The analyses are based on a FR physics parameter scan of TRU CR from 0 to [approximately]1.8 in a sodium-cooled metal-fueled FR (SMFR), in which the fuel from uranium-oxide-fueled light water reactors (LWRs) is recycled directly to FRs and FRs displace LWRs in the fleet. In this instance, the FRs are sodium cooled and metal fueled. Generally, it is assumed that all TRU elements are recycled, which maximizes uranium ore utilization for a given TRU CR and waste radiotoxicity reduction and is consistent with the assumption of used metal fuel separated by electrochemical means. In these analyses, the fuel burnup was constrained by imposing a neutron fluence limit to fuel cladding to the same constant value. This paper first presents static, time-independent measures of performance for the LWR [right arrow] FR fuel cycle, including mass, heat, gamma emission, radiotoxicity, and the two figures of merit for materials for weapon attractiveness developed by C. Bathke et al. No new fuel cycle will achieve a static equilibrium in the foreseeable future. Therefore, additional analyses are shown with dynamic, time

  15. Yttrium and rare earth stabilized fast reactor metal fuel

    DOEpatents

    Guon, Jerold; Grantham, LeRoy F.; Specht, Eugene R.

    1992-01-01

    To increase the operating temperature of a reactor, the melting point and mechanical properties of the fuel must be increased. For an actinide-rich fuel, yttrium, lanthanum and/or rare earth elements can be added, as stabilizers, to uranium and plutonium and/or a mixture of other actinides to raise the melting point of the fuel and improve its mechanical properties. Since only about 1% of the actinide fuel may be yttrium, lanthanum, or a rare earth element, the neutron penalty is low, the reactor core size can be reduced, the fuel can be burned efficiently, reprocessing requirements are reduced, and the nuclear waste disposal volumes reduced. A further advantage occurs when yttrium, lanthanum, and/or other rare earth elements are exposed to radiation in a reactor, they produce only short half life radioisotopes, which reduce nuclear waste disposal problems through much shorter assured-isolation requirements.

  16. Sensitivity Analysis of FEAST-Metal Fuel Performance Code: Initial Results

    SciTech Connect

    Edelmann, Paul Guy; Williams, Brian J.; Unal, Cetin; Yacout, Abdellatif

    2012-06-27

    This memo documents the completion of the LANL milestone, M3FT-12LA0202041, describing methodologies and initial results using FEAST-Metal. The FEAST-Metal code calculations for this work are being conducted at LANL in support of on-going activities related to sensitivity analysis of fuel performance codes. The objective is to identify important macroscopic parameters of interest to modeling and simulation of metallic fuel performance. This report summarizes our preliminary results for the sensitivity analysis using 6 calibration datasets for metallic fuel developed at ANL for EBR-II experiments. Sensitivity ranking methodology was deployed to narrow down the selected parameters for the current study. There are approximately 84 calibration parameters in the FEAST-Metal code, of which 32 were ultimately used in Phase II of this study. Preliminary results of this sensitivity analysis led to the following ranking of FEAST models for future calibration and improvements: fuel conductivity, fission gas transport/release, fuel creep, and precipitation kinetics. More validation data is needed to validate calibrated parameter distributions for future uncertainty quantification studies with FEAST-Metal. Results of this study also served to point out some code deficiencies and possible errors, and these are being investigated in order to determine root causes and to improve upon the existing code models.

  17. NMR imaging and cryoporometry of swelling clays

    NASA Astrophysics Data System (ADS)

    Dvinskikh, Sergey V.; Szutkowski, Kosma; Petrov, Oleg V.; Furó, István.

    2010-05-01

    strength as well as investigating the effect of the confining geometry and material surface properties seem to be worth to pursue. Acknowledgements: This work has been supported by the Swedish Nuclear Fuel and Waste Management Co (SKB) and the Swedish Research Council VR. References: [1] Dvinskikh S. V., Szutkowski K., Furó I. MRI profiles over a very wide concentration ranges: application to swelling of a bentonite clay. J. Magn. Reson. 198, 146 (2009). [2] Petrov O. V., Furó I. NMR cryoporometry: Principles, applications and potential. Prog. Nucl. Magn. Reson. Spec. 54, 97 (2009).

  18. High-burnup core design using minor actinide-containing metal fuel

    SciTech Connect

    Ohta, Hirokazu; Ogata, Takanari; Obara, T.

    2013-07-01

    A neutronic design study of metal fuel fast reactor (FR) cores is conducted on the basis of an innovative fuel design concept to achieve an extremely high burnup and realize an efficient fuel cycle system. Since it is expected that the burnup reactivity swing will become extremely large in an unprecedented high burnup core, minor actinides (MAs) from light water reactors (LWRs) are added to fresh fuel to improve the core internal conversion. Core neutronic analysis revealed that high burnups of about 200 MWd/kg for a small-scale core and about 300 MWd/kg for a large-scale core can be attained while suppressing the burnup reactivity swing to almost the same level as that of conventional cores with normal burnup. An actinide burnup analysis has shown that the MA consumption ratio is improved to about 60% and that the accumulated MAs originating from LWRs can be efficiently consumed by the high-burnup metal fuel FR. (authors)

  19. Mixed oxide fuel development

    SciTech Connect

    Leggett, R.D.; Omberg, R.P.

    1987-05-08

    This paper describes the success of the ongoing mixed-oxide fuel development program in the United States aimed at qualifying an economical fuel system for liquid metal cooled reactors. This development has been the cornerstone of the US program for the past 20 years and has proceeded in a deliberate and highly disciplined fashion with high emphasis on fuel reliability and operational safety as major features of an economical fuel system. The program progresses from feature testing in EBR-II to qualifying full size components in FFTF under fully prototypic conditions to establish a basis for extending allowable lifetimes. The development program started with the one year (300 EFPD) core, which is the FFTF driver fuel, continued with the demonstration of a two year (600 EFPD) core and is presently evaluating a three year (900 EFPD) fuel system. All three of these systems, consistent with other LMR fuel programs around the world, use fuel pellets gas bonded to a cladding tube that is assembled into a bundle and fitted into a wrapper tube or duct for ease of insertion into a core. The materials of construction progressed from austenitic CW 316 SS to lower swelling austenitic D9 to non swelling ferritic/martensitic HT9. 6 figs., 2 tabs.

  20. Time constants and transfer functions for a homogeneous 900 MWt metallic fueled LMR

    SciTech Connect

    Grimm, K.N.; Meneghetti, D.

    1988-01-01

    Nodal transfer functions are calculated for a 900 MWt U10Zr-fueled sodium cooled reactor. From the transfer functions the time constants, feedback reactivity transfer function coefficients, and power coefficients can be determined. These quantities are calculated for core fuel, upper and lower axial reflector steel, radial blanket fuel, radial reflector steel, and B/sub 4/C rod shaft expansion effect. The quantities are compared to the analogous quantities of a 60 MWt metallic-fueled sodium cooled Experimental Breeder Reactor II configuration. 8 refs., 2 figs., 6 tabs.

  1. Water storage of liquid-metal fast-breeder-reactor fuel

    SciTech Connect

    Meacham, S.A.

    1982-01-01

    The purpose of this paper is to present a general overview of a concept proposed for receiving and storing liquid metal fast breeder reactor (LMFBR) spent fuel. This work was done as part of the Consolidated Fuel Reprocessing Program (CFRP) at the Oak Ridge National Laboratory (ORNL). The CFRP has as its major objective the development of technology for reprocessing advanced nuclear reactor fuels. The program plans that research and development will be carried through to a sufficient scale, using irradiated spent fuel under plant operating conditions, to establish a basis for confident projection of reprocessing capability to support a breeder industry.

  2. SUB-LEU-METAL-THERM-001 SUBCRITICAL MEASUREMENTS OF LOW ENRICHED TUBULAR URANIUM METAL FUEL ELEMENTS BEFORE & AFTER IRRADIATION

    SciTech Connect

    TOFFER, H.

    2006-07-18

    With the shutdown of the Hanford PUREX (Plutonium-Uranium Extraction Plant) reprocessing plant in the 1970s, adequate storage capacity for spent Hanford N Reactor fuel elements in the K and N Reactor pools became a concern. To maximize space utilization in the pools, accounting for fuel burnup was considered. Fuel that had experienced a neutron environment in a reactor is known as spent, exposed, or irradiated fuel. In contrast fuel that has not yet been placed in a reactor is known as green, unexposed, or unirradiated fuel. Calculations indicated that at typical fuel exposures for N Reactor, the spent-fuel critical mass would be twice the critical mass for green fuel. A decision was reached to test the calculational result with a definitive experiment. If the results proved positive, storage capacity could be increased and N Reactor operation could be prolonged. An experiment to be conducted in the N Reactor spent-fuel storage pool was designed and assembled (References 1 and 2) and the services of the Battelle Northwest Laboratories (BNWL) (now Pacific Northwest National Laboratory [PNNL]) critical mass laboratory were procured for the measurements (Reference 3). The experiments were performed in April 1975 in the Hanford N Reactor fuel storage pool. The fuel elements were MKIA fuel assemblies, comprised of two concentric tubes of low-enriched metallic uranium. Two separate sets of measurements were performed: one with unirradiated fuel and one with irradiated fuel. Both the unirradiated and irradiated fuel, were measured in the same geometry. The spent-fuel MKIA assemblies had an average burnup of 2865 MWd (megawatt days)/t. A constraint was imposed restricting the measurements to a subcritical limit of k{sub eff} = 0.97. Subcritical count rate data was obtained with pulsed-neutron and approach-to-critical measurements. Ten (10) configurations with green fuel and nine (9) configurations with spent fuel are described and evaluated. Of these, three (3) green fuel

  3. PROCESSING OF URANIUM-METAL-CONTAINING FUEL ELEMENTS

    DOEpatents

    Moore, R.H.

    1962-10-01

    A process is given for recovering uranium from neutronbombarded uranium- aluminum alloys. The alloy is dissolved in an aluminum halide--alkali metal halide mixture in which the halide is a mixture of chloride and bromide, the aluminum halide is present in about stoichiometric quantity as to uranium and fission products and the alkali metal halide in a predominant quantity; the uranium- and electropositive fission-products-containing salt phase is separated from the electronegative-containing metal phase; more aluminum halide is added to the salt phase to obtain equimolarity as to the alkali metal halide; adding an excess of aluminum metal whereby uranium metal is formed and alloyed with the excess aluminum; and separating the uranium-aluminum alloy from the fission- productscontaining salt phase. (AEC)

  4. Calculation of radiation induced swelling of uranium mononitride using the digital computer program CYGRO 2

    NASA Technical Reports Server (NTRS)

    Davison, H. W.; Fiero, I. B.

    1971-01-01

    Fuel volume swelling and clad diametral creep strains were calculated for five fuel pins, clad with either T-111 (Ta-8W-2.4Hf) or PWC-11 (Nb-1Zr-0.1C). The fuel pins were irradiated to burnups between 2.7 and 4.6%. Clad temperatures were between 1750 and 2400 F (1228 and 1589 K). The maximum percentage difference between calculated and experimentally measured values of volumetric fuel swelling is 60%.

  5. Characterization of Irradiated Metal Waste from the Pyrometallurgical Treatment of Used EBR-II Fuel

    SciTech Connect

    B.R. Westphal; K.C. Marsden; W.M. McCartin; S.M. Frank; D.D. Keiser, Jr.; T.S. Yoo; D. Vaden; D.G. Cummings; K.J. Bateman; J. J. Giglio; T. P. O'Holleran; P. A. Hahn; M. N. Patterson

    2013-03-01

    As part of the pyrometallurgical treatment of used Experimental Breeder Reactor-II fuel, a metal waste stream is generated consisting primarily of cladding hulls laden with fission products noble to the electrorefining process. Consolidation by melting at high temperature [1873 K (1600 degrees C)] has been developed to sequester the noble metal fission products (Zr, Mo, Tc, Ru, Rh, Te, and Pd) which remain in the iron-based cladding hulls. Zirconium from the uranium fuel alloy (U-10Zr) is also deposited on the hulls and forms Fe-Zr intermetallics which incorporate the noble metals as well as residual actinides during processing. Hence, Zr has been chosen as the primary indicator for consistency of the metal waste. Recently, the first production-scale metal waste ingot was generated and sampled to monitor Zr content for Fe-Zr intermetallic phase formation and validation of processing conditions. Chemical assay of the metal waste ingot revealed a homogeneous distribution of the noble metal fission products as well as the primary fuel constituents U and Zr. Microstructural characterization of the ingot confirmed the immobilization of the noble metals in the Fe-Zr intermetallic phase.

  6. Characterization of Irradiated Metal Waste from the Pyrometallurgical Treatment of Used EBR-II Fuel

    NASA Astrophysics Data System (ADS)

    Westphal, Brian R.; Frank, S. M.; McCartin, W. M.; Cummings, D. G.; Giglio, J. J.; O'Holleran, T. P.; Hahn, P. A.; Yoo, T. S.; Marsden, K. C.; Bateman, K. J.; Patterson, M. N.

    2015-01-01

    As part of the pyrometallurgical treatment of used Experimental Breeder Reactor-II fuel, a metal waste stream is generated consisting primarily of cladding hulls laden with fission products noble to the electrorefining process. Consolidation by melting at high temperature [1873 K (1600 °C)] has been developed to sequester the noble metal fission products (Zr, Mo, Tc, Ru, Rh, Te, and Pd) which remain in the iron-based cladding hulls. Zirconium from the uranium fuel alloy (U-10Zr) is also deposited on the hulls and forms Fe-Zr intermetallics which incorporate the noble metals as well as residual actinides during processing. Hence, Zr has been chosen as the primary indicator for consistency of the metal waste. Recently, the first production-scale metal waste ingot was generated and sampled to monitor Zr content for Fe-Zr intermetallic phase formation and validation of processing conditions. Chemical assay of the metal waste ingot revealed a homogeneous distribution of the noble metal fission products as well as the primary fuel constituents U and Zr. Microstructural characterization of the ingot confirmed the immobilization of the noble metals in the Fe-Zr intermetallic phase.

  7. Nano-structured noble metal catalysts based on hexametallate architecture for the reforming of hydrocarbon fuels

    DOEpatents

    Gardner, Todd H.

    2015-09-15

    Nano-structured noble metal catalysts based on hexametallate lattices, of a spinel block type, and which are resistant to carbon deposition and metal sulfide formation are provided. The catalysts are designed for the reforming of hydrocarbon fuels to synthesis gas. The hexametallate lattices are doped with noble metals (Au, Pt, Rh, Ru) which are atomically dispersed as isolated sites throughout the lattice and take the place of hexametallate metal ions such as Cr, Ga, In, and/or Nb. Mirror cations in the crystal lattice are selected from alkali metals, alkaline earth metals, and the lanthanide metals, so as to reduce the acidity of the catalyst crystal lattice and enhance the desorption of carbon deposit forming moieties such as aromatics. The catalysts can be used at temperatures as high as 1000.degree. C. and pressures up to 30 atmospheres. A method for producing these catalysts and applications of their use also is provided.

  8. Method for producing hydrocarbon fuels from heavy polynuclear hydrocarbons by use of molten metal halide catalyst

    DOEpatents

    Gorin, Everett

    1979-01-01

    In a process for hydrocracking heavy polynuclear carbonaceous feedstocks to produce lighter hydrocarbon fuels by contacting the heavy feedstocks with hydrogen in the presence of a molten metal halide catalyst, thereafter separating at least a substantial portion of the carbonaceous material associated with the reaction mixture from the spent molten metal halide and thereafter regenerating the metal halide catalyst, an improvement comprising contacting the spent molten metal halide catalyst after removal of a major portion of the carbonaceous material therefrom with an additional quantity of hydrogen is disclosed.

  9. Microstructural Changes In Thermally Cycled U-Pu-Zr-Am-Np Metallic Transmutation Fuel With 1.5% Lanthanides

    SciTech Connect

    Dawn E. Janney; J. Rory Kennedy

    2008-06-01

    The United States Department of Energy (DOE) Global Nuclear Energy Partnership (GNEP) is developing metallic actinide-zirconium alloy fuels for the transmutation of minor actinides as part of a closed fuel cycle. The molten salt electrochemical process to be used for fuel recycle has the potential to carry over up to 2% fission product lanthanide content into the fuel fabrication process. Within the scope of the fuel irradiation testing program at Idaho National Laboratory (INL), candidate metal alloy transmutation fuels containing quantities of lanthanide elements have been fabricated, characterized, and delivered to the Advanced Test Reactor for irradiation testing.

  10. Measuring the Noble Metal and Iodine Composition of Extracted Noble Metal Phase from Spent Nuclear Fuel Using Instrumental Neutron Activation Analysis

    SciTech Connect

    Palomares, R. I.; Dayman, Kenneth J.; Landsberger, Sheldon; Biegalski, Steven R.; Soderquist, Chuck Z.; Casella, Amanda J.; Brady Raap, Michaele C.; Schwantes, Jon M.

    2015-04-01

    Mass quantities of noble metal and iodine nuclides in the metallic noble metal phase extracted from spent fuel are measured using instrumental neutron activation analysis (NAA). Nuclide presence is predicted using fission yield analysis, and mass quantification is derived from standard gamma spectroscopy and radionuclide decay analysis. The nuclide compositions of noble metal phase derived from two dissolution methods, UO2 fuel dissolved in nitric acid and UO2 fuel dissolved in ammonium-carbonate and hydrogen-peroxide solution, are compared. Lastly, the implications of the rapid analytic speed of instrumental NAA are discussed in relation to potential nuclear forensics applications.

  11. Alkaline polymer electrolyte fuel cells completely free from noble metal catalysts

    PubMed Central

    Lu, Shanfu; Pan, Jing; Huang, Aibin; Zhuang, Lin; Lu, Juntao

    2008-01-01

    In recent decades, fuel cell technology has been undergoing revolutionary developments, with fundamental progress being the replacement of electrolyte solutions with polymer electrolytes, making the device more compact in size and higher in power density. Nowadays, acidic polymer electrolytes, typically Nafion, are widely used. Despite great success, fuel cells based on acidic polyelectrolyte still depend heavily on noble metal catalysts, predominantly platinum (Pt), thus increasing the cost and hampering the widespread application of fuel cells. Here, we report a type of polymer electrolyte fuel cells (PEFC) employing a hydroxide ion-conductive polymer, quaternary ammonium polysulphone, as alkaline electrolyte and nonprecious metals, chromium-decorated nickel and silver, as the catalyst for the negative and positive electrodes, respectively. In addition to the development of a high-performance alkaline polymer electrolyte particularly suitable for fuel cells, key progress has been achieved in catalyst tailoring: The surface electronic structure of nickel has been tuned to suppress selectively the surface oxidative passivation with retained activity toward hydrogen oxidation. This report of a H2–O2 PEFC completely free from noble metal catalysts in both the positive and negative electrodes represents an important advancement in the research and development of fuel cells.

  12. Design and fabrication of specific ceramic?metallic fuels and targets

    NASA Astrophysics Data System (ADS)

    Fernández, A.; Konings, R. J. M.; Somers, J.

    2003-06-01

    The fabrication of ceramic-metallic (cermet) composite fuel, containing (Y,An,Zr)O 2- x spheres, by dust free processes has been studied. The influence of several process parameters, such as, ceramic volume fraction, compaction pressure and sintering temperature, on the microstructure of the final composite have been investigated and optimised using cerium as a stand for americium and two metal matrices namely molybdenum and stainless steel. In addition, a cermet fuel with (near) spherical (Y,Pu,Zr)O 2- x particles, dispersed in stainless steel matrix, has been successfully fabricated and characterized.

  13. Fission product release phenomena during core melt accidents in metal fueled heavy water reactors

    SciTech Connect

    Ellison, P G; Hyder, M L; Monson, P R; Randolph, H W; Hagrman, D L; McClure, P R; Leonard, M T

    1990-01-01

    The phenomena that determine fission product release rates from a core melting accident in a metal-fueled, heavy water reactor are described in this paper. This information is obtained from the analysis of the current metal fuel experimental data base and from the results of analytical calculations. Experimental programs in place at the Savannah River Site are described that will provide information to resolve uncertainties in the data base. The results of the experiments will be incorporated into new severe accident computer codes recently developed for this reactor design. 47 refs., 4 figs.

  14. Study of metallic materials for solid oxide fuel cell interconnect applications.

    SciTech Connect

    Natesan, K.; Zeng, Z.; Nuclear Engineering Division

    2009-04-24

    Metallic interconnect acts as a gas separator and a gas distributor and therefore, it needs to function adequately in two widely different environments. The interconnect material will be exposed to air on one side and natural gas or coal-derived synthesis gas on the other side. The viable material for the interconnect application must be resistant not only to oxidation but also carburization in hydrocarbon containing low-oxygen environments. In addition, the scales that develop on the exposed surfaces must possess adequate electrical conductivity for them to function as current leads over long service life of the fuel cell. This report addresses five topics of interest for the development of metallic interconnects with adequate performance in fuel cells for long service life. The research conducted over the years and the conclusions reached were used to identify additional areas of research on materials for improved performance of components, especially metallic interconnects, in the complex fuel cell environments. This report details research conducted in the following areas: measurement of area specific electrical resistivity, corrosion performance in dual gas environments by experiments using alloy 446, long term corrosion performance of ferritic and austenitic alloys in hydrogen and methane-reformed synthesis fuel-gas environments, approaches to reduce the area resistance of metallic interconnect, and reduction of electrical resistivity of alumina scales on metallic interconnect. Based on the key requirements for metallic interconnects and the data developed on the corrosion behavior of candidate materials in meeting those requirements, several areas are recommended for further research to develop metallic interconnects with acceptable and reliable long-term performance in solid oxide fuel cells.

  15. Irradiation experiment on fast reactor metal fuels containing minor actinides up to 7 at.% burnup

    SciTech Connect

    Ohta, H.; Yokoo, T.; Ogata, T.; Inoue, T.; Ougier, M.; Glatz, J.P.; Fontaine, B.; Breton, L.

    2007-07-01

    Fast reactor metal fuels containing minor actinides (MAs: Np, Am, Cm) and rare earths (REs) have been irradiated in the fast reactor PHENIX. In this experiment, four types of fuel alloys, U-19Pu-10Zr, U-19Pu-10Zr-2MA-2RE, U-19Pu-10Zr-5MA-5RE and U-19Pu-10Zr-5MA (wt.%), are loaded into part of standard metal fuel stacks. The postirradiation examinations will be conducted at {approx}2.4, {approx}7 and {approx}11 at.% burnup. As for the low-burnup fuel pins, nondestructive postirradiation tests have already been performed and the fuel integrity was confirmed. Furthermore, the irradiation experiment for the intermediate burnup goal of {approx}7 at.% was completed in July 2006. For the irradiation period of 356.63 equivalent full-power days, the neutron flux level remained in the range of 3.5-3.6 x 10{sup 15} n/cm{sup 2}/s at the axial peak position. On the other hand, the maximum linear power of fuel alloys decreased gradually from 305-315 W/cm (beginning of irradiation) to 250-260 W/cm (end of irradiation). The discharged peak burnup was estimated to be 6.59-7.23 at.%. The irradiation behavior of MA-containing metal fuels up to 7 at.% burnup was predicted using the ALFUS code, which was developed for U-Pu-Zr ternary fuel performance analysis. As a result, it was evaluated that the fuel temperature is distributed between {approx}410 deg. C and {approx}645 deg. C at the end of the irradiation experiment. From the stress-strain analysis based on the preliminarily employed cladding irradiation properties and the FCMI stress distribution history, it was predicted that a cladding strain of not more than 0.9% would appear. (authors)

  16. The Swelling of Olympic Gels

    NASA Astrophysics Data System (ADS)

    Lang, Michael; Fischer, Jakob; Werner, Marco; Sommer, Jens-Uwe

    2014-03-01

    The swelling equilibrium of Olympic gels is studied by Monte Carlo Simulations. We observe that gels consisting of flexible cyclic molecules of a higher degree of polymerization N show a smaller equilibrium swelling degree Q ~N - 0 . 28φ0- 0 . 72 for the same monomer volume fraction φ0 at network preparation. This observation is explained by a disinterpenetration process of overlapping non-concatenated polymers upon swelling. In the limit of a sufficiently large number of concatenations per cyclic molecule we expect that the equilibrium degree of swelling becomes proportional to φ0- 1 / 2 independent of N. Our results challenge current textbook models for the equilibrium degree of swelling of entangled polymer networks. Now at: Bio Systems Analysis Group, Jena Centre for Bioinformatics (JCB) and Department for Mathematics and Computer Sciences, Friedrich Schiller University of Jena, 07743 Jena, Germany.

  17. Conducting polymer-coated corrosion resistant metallic bipolar plates for proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Joseph, Shine

    2005-11-01

    Concerns over depleting stocks of natural resources and a growing awareness of the environmental damage caused by widespread burning of fossil fuels, and more energy demands brought the idea of alternative energy systems. Proton Exchange Membrane (PEM) fuel cells are one of the fast growing alternative energy technologies. PEM fuel cells generate electricity from an electrochemical reaction between hydrogen and oxygen and produce electricity, a small amount of heat and water and therefore, they are environmentally friendly. Fuel cells are more efficient than internal combustion engines and operate continuously as long as fuel is supplied from an external tank. Fuel cells in stacks are used for most applications because the current output of a PEM fuel cell is around 0.3--0.5 A/cm2. In fuel cell stacks, bipolar plates combine two cells in series with anode and cathode of adjacent cells. The main functions of bipolar plates are electron and gas transport. Bipolar plates are major components in weight and volume of the PEM fuel cell stack and are a significant contributor to the stack cost. The bipolar plate is therefore a key component if power density is to increase and cost to come down. Bipolar plate material should be corrosion resistant, conductive, gas impermeable, light weight (mobile applications) and economical. Graphite plates are used for bipolar plate applications but they are expensive, are brittle to make in thin plates with gas channels on sides, have high manufacturing cost and are gas permeable if too thin. Metals are preferable for bipolar plate application because of better mechanical properties, higher electrical conductivity, lower gas permeability and low cost. In this work Al 6061 and 304 stainless steel alloys are the materials selected for bipolar plates. These metals form non-conductive surface oxides in a PEM fuel cell environment and cause a high contact resistance. This internal resistance lowers the efficiency of PEM fuel cell system. In

  18. Liquid Metal Bond for Improved Heat Transfer in LWR Fuel Rods

    SciTech Connect

    Donald Olander

    2005-08-24

    A liquid metal (LM) consisting of 1/3 weight fraction each of Pb, Sn, and Bi has been proposed as the bonding substance in the pellet-cladding gap in place of He. The LM bond eliminates the large AT over the pre-closure gap which is characteristic of helium-bonded fuel elements. Because the LM does not wet either UO2 or Zircaloy, simply loading fuel pellets into a cladding tube containing LM at atmospheric pressure leaves unfilled regions (voids) in the bond. The HEATING 7.3 heat transfer code indicates that these void spaces lead to local fuel hot spots.

  19. Metallic fast reactor fuel fabrication for the global nuclear energy partnership

    NASA Astrophysics Data System (ADS)

    Burkes, Douglas E.; Fielding, Randall S.; Porter, Douglas L.

    2009-07-01

    Fast reactors are once again being considered for nuclear power generation, in addition to transmutation of long-lived fission products resident in spent nuclear fuels. This re-consideration follows with intense developmental programs for both fuel and reactor design. One of the two leading candidates for next generation fast reactor fuel is metal alloys, resulting primarily from the successes achieved in the 1960s to early 1990s with both the experimental breeding reactor-II and the fast flux test facility. The goal of the current program is to develop and qualify a nuclear fuel system that performs all of the functions of a conventional, fast-spectrum nuclear fuel while destroying recycled actinides, thereby closing the nuclear fuel cycle. In order to meet this goal, the program must develop efficient and safe fuel fabrication processes designed for remote operation. This paper provides an overview of advanced casting processes investigated in the past, and the development of a gaseous diffusion calculation that demonstrates how straightforward process parameter modification can mitigate the loss of volatile minor actinides in the metal alloy melt.

  20. Metallography and fuel cladding chemical interaction in fast flux test facility irradiated metallic U-10Zr MFF-3 and MFF-5 fuel pins

    NASA Astrophysics Data System (ADS)

    Carmack, W. J.; Chichester, H. M.; Porter, D. L.; Wootan, D. W.

    2016-05-01

    The Mechanistic Fuel Failure (MFF) series of metal fuel irradiations conducted in the Fast Flux Test Facility (FFTF) provides an important comparison between data generated in the Experimental Breeder Reactor (EBR-II) and that expected in a larger-scale fast reactor. The MFF fuel operated with a peak cladding temperature at the top of the fuel column, but developed peak burnup at the centerline of the core. This places the peak fuel temperature midway between the core center and the top of fuel, lower in the fuel column than in EBR-II experiments. Data from the MFF-3 and MFF-5 assemblies are most comparable to the data obtained from the EBR-II X447 experiment. The two X447 pin breaches were strongly influenced by fuel/cladding chemical interaction (FCCI) at the top of the fuel column. Post irradiation examination data from MFF-3 and MFF-5 are presented and compared to historical EBR-II data.

  1. Fabrication of U-10 wt.%Zr Metallic Fuel Rodlets for Irradiation Test in BOR-60 Fast Reactor

    DOE PAGES

    Kim, Ki-Hwan; Kim, Jong-Hwan; Oh, Seok-Jin; Lee, Jung-Won; Lee, Ho-Jin; Lee, Chan-Bock

    2016-01-01

    The fabrication technology for metallic fuel has been developed to produce the driver fuel in a PGSFR in Korea since 2007. In order to evaluate the irradiation integrity and validate the in-reactor of the starting metallic fuel with FMS cladding for the loading of the metallic fuel, U-10 wt.%Zr fuel rodlets were fabricated and evaluated for a verification of the starting driver fuel through an irradiation test in the BOR-60 fast reactor. The injection casting method was applied to U-10 wt.%Zr fuel slugs with a diameter of 5.5 mm. Consequently, fuel slugs per melting batch without casting defects were fabricated through the developmentmore » of advanced casting technology and evaluation tests. The optimal GTAW welding conditions were also established through a number of experiments. In addition, a qualification test was carried out to prove the weld quality of the end plug welding of the metallic fuel rodlets. The wire wrapping of metallic fuel rodlets was successfully accomplished for the irradiation test. Thus, PGSFR fuel rodlets have been soundly fabricated for the irradiation test in a BOR-60 fast reactor.« less

  2. Investigation of novel electrolyte systems for advanced metal/air batteries and fuel cells

    NASA Astrophysics Data System (ADS)

    Ye, Hui

    It is a worldwide challenge to develop advanced green power sources for modern portable devices, transportation and stationary power generation. Metal/air batteries and fuel cells clearly stand out in view of their high specific energy, high energy efficiency and environment-friendliness. Advanced metal/air batteries based on metal ion conductors and proton exchange membrane (PEM) fuel cells operated at elevated temperatures (>120°C) can circumvent the limitations of current technologies and bring considerable advantages. The key is to develop suitable electrolytes to enable these new technologies. In this thesis research, investigation of novel electrolytes systems for advanced metal/air batteries and PEM fuel cells is conducted. Novel polymer gel electrolyte systems, [metal salt/ionic liquid/polymer] and [metal salt/liquid polyether/polymer] are prepared. Such systems contain no volatile solvents, conduct metal ions (Li+ or Zn 2+) with high ionic conductivity, possess wide electrochemical stability windows, and exhibit wide operating temperature ranges. They promise to enable non-aqueous, all-solid-state, thin-film Li/air batteries and Zn/air batteries. They are advantageous for application in other battery systems as well, such as rechargeable lithium and lithium ion batteries. In the case of proton exchange membranes, polymer gel electrolyte systems [acid/ionic liquid/polymer] are prepared. Especially, H3PO4/PMIH2PO 4/PBI is demonstrated as prospective proton exchange membranes for PEM fuel cells operating at elevated temperatures. Comprehensive electrochemical characterization, thermal analysis (TGA and DSC) and spectroscopy analysis (NMR and FTIR) are carried out to investigate these novel electrolyte systems and their ion transport mechanisms. The design and synthesis of novel ionic liquids and electrolyte systems based on them for advantageous application in various electrochemical power sources are highlighted in this work.

  3. Creep resistant, metal-coated LiFeO[sub 2] anodes for molten carbonated fuel cells

    DOEpatents

    Khandkar, A.C.

    1994-08-23

    A porous, creep-resistant, metal-coated, LiFeO[sub 2] ceramic electrode for fuel cells is disclosed. The electrode is particularly useful for molten carbonate fuel cells (MCFC) although it may have utilities in solid oxide fuel cells (SOFC) as well. 11 figs.

  4. Creep resistant, metal-coated LiFeO.sub.2 anodes for molten carbonated fuel cells

    DOEpatents

    Khandkar, Ashok C.

    1994-01-01

    A porous, creep-resistant, metal-coated, LiFeO.sub.2 ceramic electrode for fuel cells is disclosed. The electrode is particularly useful for molten carbonate fuel cells (MCFC) although it may have utilities in solid oxide fuel cells (SOFC) as well.

  5. Chemical Forms and Distribution of Platinum Group Metals and Technetium During Spent Fuel Reprocessing

    SciTech Connect

    Pokhitonov, Y.

    2007-07-01

    Amongst the fission products present in spent nuclear fuel of Nuclear Power Plants there are considerable quantities of platinum group metals (PGMs): ruthenium, rhodium and palladium. At the same time there are considerable amounts of technetium in the spent fuel, the problem of its removal at radiochemical plants being in operation encountering serious difficulties. Increased interest in this radionuclides is due not only to its rather large yield, but to higher mobility in the environment as well. However, the peculiarities of technetium chemistry in nitric acid solutions create certain problems when trying to separate it as a single product in the course of NPP's spent fuel reprocessing. The object of this work was to conduct a comprehensive analysis of platinum group metals and technetium behavior at various stages of spent fuel reprocessing and to seek the decisions which could make it possible to separate its as a single product. The paper will report data on platinum metals (PGM) and technetium distribution in spent fuel reprocessing products. The description of various techniques for palladium recovery from differing in composition radioactive solutions arising from reprocessing is given. (authors)

  6. Stabilized metal nanoparticles from organometallic precursors for low temperature fuel cells.

    PubMed

    Ramirez-Meneses, E; Dominguez-Crespo, M A; Torres-Huerta, A M

    2013-01-01

    In this work, a review of articles and patents related to the utilization of colloidal metal nanoparticles produced by the decomposition of organometallic precursors as supported electrocatalysts in different electrochemical reactions including hydrogen evolution reaction (HER), oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) is discussed. In the case of stabilized metal nanoparticles, the kind of functional group contained in the stabilizer as well as the metal/stabilizer ratio, to evaluate the effect of particle size on the electrochemical performance, were also debated. Potential applications and perspectives of these electrocatalysts in proton exchange membrane fuel cells (PEMFC) are contended with reference to the role played by the coordination compounds and costs.

  7. Determination of Uranium Metal Concentration in Irradiated Fuel Storage Basin Sludge Using Selective Dissolution

    SciTech Connect

    Delegard, Calvin H.; Sinkov, Sergey I.; Chenault, Jeffrey W.; Schmidt, Andrew J.; Welsh, Terri L.; Pool, Karl N.

    2014-03-01

    Uranium metal corroding in water-saturated sludges now held in the US Department of Energy Hanford Site K West irradiated fuel storage basin can create hazardous hydrogen atmospheres during handling, immobilization, or subsequent transport and storage. Knowledge of uranium metal concentration in sludge thus is essential to safe sludge management and process design, requiring an expeditious routine analytical method to detect uranium metal concentrations as low as 0.03 wt% in sludge even in the presence of 30 wt% or higher total uranium concentrations.

  8. Development and analysis of a metal-fueled accelerator-driven burner

    SciTech Connect

    Lypsch, F.; Hill, R.N.

    1994-08-01

    The purpose of this paper is to compare the safety characteristics of an accelerator driven metal fueled fast system to a critical core on a consistent basis to determine how these characteristics are affected solely by subcritically of the system. To accomplish this an accelerator proton beam/tungsten neutron source model is surrounded by a subcritical blanket using metallic fuel and sodium as coolant. The consequences of typical accident transients, namely unprotected transient overpower (TOP), loss of heat sink (LOHS), and loss of flow (LOP) were calculated for the hybrid system and compared to corresponding results for a metal-fueled fast reactor. Results indicate that the subcritical system exhibits superior performance for TOP (reactivity-induced) transits; however, only in the critical system are reactivity feedbacks able to cause passive shutdown in the LOHS ad LOP events. Therefore, for a full spectrum of accident initiators considered, the overall safety behavior of accelerator-driven metal-fueled systems can neither be concluded to be worse nor to be better than advanced reactor designs which rely on passive safety features.

  9. Corrosion-resistant fuel cladding allow for liquid metal fast breeder reactors

    DOEpatents

    Brehm, Jr., William F.; Colburn, Richard P.

    1982-01-01

    An aluminide coating for a fuel cladding tube for LMFBRs (liquid metal fast breeder reactors) such as those using liquid sodium as a heat transfer agent. The coating comprises a mixture of nickel-aluminum intermetallic phases and presents good corrosion resistance to liquid sodium at temperatures up to 700.degree. C. while additionally presenting a barrier to outward diffusion of .sup.54 Mn.

  10. Optimisation of composite metallic fuel for minor actinide transmutation in an accelerator-driven system

    NASA Astrophysics Data System (ADS)

    Uyttenhove, W.; Sobolev, V.; Maschek, W.

    2011-09-01

    A potential option for neutralization of minor actinides (MA) accumulated in spent nuclear fuel of light water reactors (LWRs) is their transmutation in dedicated accelerator-driven systems (ADS). A promising fuel candidate dedicated to MA transmutation is a CERMET composite with Mo metal matrix and (Pu, Np, Am, Cm)O 2-x fuel particles. Results of optimisation studies of the CERMET fuel targeting to increasing the MA transmutation efficiency of the EFIT (European Facility for Industrial Transmutation) core are presented. In the adopted strategy of MA burning the plutonium (Pu) balance of the core is minimized, allowing a reduction in the reactivity swing and the peak power form-factor deviation and an extension of the cycle duration. The MA/Pu ratio is used as a variable for the fuel optimisation studies. The efficiency of MA transmutation is close to the foreseen theoretical value of 42 kg TW -1 h -1 when level of Pu in the actinide mixture is about 40 wt.%. The obtained results are compared with the reference case of the EFIT core loaded with the composite CERCER fuel, where fuel particles are incorporated in a ceramic magnesia matrix. The results of this study offer additional information for the EFIT fuel selection.

  11. Metal Interconnects for Solid Oxide Fuel Cell Power Systems

    SciTech Connect

    S. Elangovan

    2006-04-01

    Interconnect development is identified by the US Department of energy as a key technical area requiring focused research to meet the performance and cost goals under the Solid State Energy Conversion Alliance initiative. In the Phase I SECA Core Technology Program, Ceramatec investigated a commercial ferritic stainless steel composition for oxidation resistance properties by measuring the weight gain when exposed to air at the fuel cell operating temperature. A pre-treatment process that results in a dense, adherent scale was found to reduce the oxide scale growth rate significantly. A process for coating the surface of the alloy in order to reduce the in-plane resistance and potentially inhibit chromium oxide evaporation was also identified. The combination of treatments provided a very low resistance through the scale. The resistance measured was as low as 10 milliohm-cm2 at 750 C in air. The oxide scale was also found to be stable in humidified air at 750 C. The resistance value was stable over several thermal cycles. A similar treatment and coating for the fuel side of the interconnect also showed an exceptionally low resistance of one milliohm-cm2 in humidified hydrogen at 750 c, and was stable through multiple thermal cycles. Measurement of interconnect resistance when it was exposed to both air and humidified hydrogen on opposite sides also showed low, stable resistance after additional modification to the pre-treatment process. Resistance stacks, using an interconnect stack with realistic gas flows, also provided favorable results. Chromium evaporation issue however requires testing of fuel stacks and was outside of the scope of this project. based on results to-date, the alloy selection and the treatment processes appear to be well suited for SOFC interconnect application.

  12. Metal-catalyst-free carbohydrazide fuel cells with three-dimensional graphene anodes.

    PubMed

    Qi, Ji; Benipal, Neeva; Wang, Hui; Chadderdon, David J; Jiang, Yibo; Wei, Wei; Hu, Yun Hang; Li, Wenzhen

    2015-04-13

    As a potential solution to concerns on sustainable energy, the wide spread commercialization of fuel cell has long been hindered by limited reserves and relatively high costs of metal catalysts. 3D graphene, a carbon-only catalyst prepared by reduction of carbon monoxide with lithium oxide, is found to electrochemically catalyze carbohydrazide oxidation reaction efficiently. A prototype of a completely metal-catalyst-free anion exchange membrane fuel cell (AEMFC) with a 3D graphene anode catalyst and an N-doped CNT (N-CNT) cathode catalyst generate a peak power density of 24.9 mW cm(-2) . The average number of electrons electrochemically extracted from one carbohydrazide molecule is 4.9, indicating the existence of CN bond activation, which is a key factor contributing to high fuel utilization efficiency.

  13. Metal-catalyst-free carbohydrazide fuel cells with three-dimensional graphene anodes.

    PubMed

    Qi, Ji; Benipal, Neeva; Wang, Hui; Chadderdon, David J; Jiang, Yibo; Wei, Wei; Hu, Yun Hang; Li, Wenzhen

    2015-04-13

    As a potential solution to concerns on sustainable energy, the wide spread commercialization of fuel cell has long been hindered by limited reserves and relatively high costs of metal catalysts. 3D graphene, a carbon-only catalyst prepared by reduction of carbon monoxide with lithium oxide, is found to electrochemically catalyze carbohydrazide oxidation reaction efficiently. A prototype of a completely metal-catalyst-free anion exchange membrane fuel cell (AEMFC) with a 3D graphene anode catalyst and an N-doped CNT (N-CNT) cathode catalyst generate a peak power density of 24.9 mW cm(-2) . The average number of electrons electrochemically extracted from one carbohydrazide molecule is 4.9, indicating the existence of CN bond activation, which is a key factor contributing to high fuel utilization efficiency. PMID:25469500

  14. Metal supported tubular solid oxide fuel cells fabricated by suspension plasma spray and suspension high velocity oxy-fuel spray

    NASA Astrophysics Data System (ADS)

    Yoo, Yeong; Wang, Youliang; Deng, Xiaohua; Singh, Devinder; Legoux, Jean-Gabriel

    2012-10-01

    Low temperature (LT) metal supported solid oxide fuel cells (SOFCs) have many advantages in comparison to conventional electrode or electrolyte supported type SOFCs. NRC has demonstrated high performance LT metal supported planar SOFCs fabricated by either wet colloidal spray/sintering or suspension thermal spray. The combination of tubular configuration and metal supported SOFCs may produce more unique and very attractive advantages such as easy and inexpensive sealing method and materials, high specific and volumetric power density, cost-effective fabrication, enhanced robustness, rapid start up, red-ox cycle tolerance and potential use for a pressurized integrated system. In this paper, thin film solid electrolyte of Sm0.2Ce0.8O1.90 (SDC) and NiO-SDC composite anode on sintered porous tubular metal supports were deposited by suspension HVOF spray and suspension plasma spray, respectively on sintered porous tubular metal support. La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode on the SDC electrolyte was formed by wet colloidal spray and subsequent sintering process as the final fabrication step. The detailed investigation of suspension and process-related parameters for suspension thermal spray was performed in order to produce thin and crack-free SDC thin film coatings. The electrochemical performance of single cells was demonstrated.

  15. Performance evaluation and characterization of metallic bipolar plates in a proton exchange membrane (PEM) fuel cell

    NASA Astrophysics Data System (ADS)

    Hung, Yue

    Bipolar plate and membrane electrode assembly (MEA) are the two most repeated components of a proton exchange membrane (PEM) fuel cell stack. Bipolar plates comprise more than 60% of the weight and account for 30% of the total cost of a fuel cell stack. The bipolar plates perform as current conductors between cells, provide conduits for reactant gases, facilitate water and thermal management through the cell, and constitute the backbone of a power stack. In addition, bipolar plates must have excellent corrosion resistance to withstand the highly corrosive environment inside the fuel cell, and they must maintain low interfacial contact resistance throughout the operation to achieve optimum power density output. Currently, commercial bipolar plates are made of graphite composites because of their relatively low interfacial contact resistance (ICR) and high corrosion resistance. However, graphite composite's manufacturability, permeability, and durability for shock and vibration are unfavorable in comparison to metals. Therefore, metals have been considered as a replacement material for graphite composite bipolar plates. Since bipolar plates must possess the combined advantages of both metals and graphite composites in the fuel cell technology, various methods and techniques are being developed to combat metallic corrosion and eliminate the passive layer formed on the metal surface that causes unacceptable power reduction and possible fouling of the catalyst and the electrolyte. The main objective of this study was to explore the possibility of producing efficient, cost-effective and durable metallic bipolar plates that were capable of functioning in the highly corrosive fuel cell environment. Bulk materials such as Poco graphite, graphite composite, SS310, SS316, incoloy 800, titanium carbide and zirconium carbide were investigated as potential bipolar plate materials. In this work, different alloys and compositions of chromium carbide coatings on aluminum and SS316

  16. High temperature corrosion of metallic materials in molten carbonate fuel cells environment

    NASA Astrophysics Data System (ADS)

    Durante, G.; Vegni, S.; Capobianco, P.; Golgovici, F.

    Molten carbonate fuel cells (MCFCs) are electrochemical devices that convert energy of a chemical reaction into electricity without any kind of combustion. So, MCFCs are promising for their high efficiency and their low environmental pollution. A limiting aspect for reaching the goal of 40,000 h of life-time is the corrosion of metallic parts of MCFC, especially for current collectors and separator plates. Generally, this corrosion leads to metal loss and to an important increase of the electrical resistance due to the formation of resistive oxides. One of the most critic components in a MCFC is the anodic side metallic components. More used choice for these components is actually a sheet of AISI310S cladded at both sides by a Ni layer. The analysis of the behaviour of this material after different steps of corrosion in a typical molten carbonate fuel cell environment could be important to understand some phenomena that cause the damage of the anodic current collector.

  17. Nanostructure of Metallic Particles in Light Water Reactor Used Nuclear Fuel

    SciTech Connect

    Buck, Edgar C.; Mausolf, Edward J.; Mcnamara, Bruce K.; Soderquist, Chuck Z.; Schwantes, Jon M.

    2015-03-11

    The extraordinary nano-structure of metallic particles in light water reactor fuels points to possible high reactivity through increased surface area and a high concentration of high energy defect sites. We have analyzed the metallic epsilon particles from a high burn-up fuel from a boiling water reactor using transmission electron microscopy and have observed a much finer nanostructure in these particles than has been reported previously. The individual round particles that varying in size between ~20 and ~50 nm appear to consist of individual crystallites on the order of 2-3 nm in diameter. It is likely that in-reactor irradiation induce displacement cascades results in the formation of the nano-structure. The composition of these metallic phases is variable yet the structure of the material is consistent with the hexagonal close packed structure of epsilon-ruthenium. These findings suggest that unusual catalytic behavior of these materials might be expected, particularly under accident conditions.

  18. History of fast reactor fuel development

    NASA Astrophysics Data System (ADS)

    Kittel, J. H.; Frost, B. R. T.; Mustelier, J. P.; Bagley, K. Q.; Crittenden, G. C.; Van Dievoet, J.

    1993-09-01

    The first fast breeder reactors, constructed in the 1945-1960 time period, used metallic fuels composed of uranium, plutonium, or their alloys. They were chosen because most existing reactor operating experience had been obtained on metallic fuels and because they provided the highest breeding ratios. Difficulties in obtaining adequate dimensional stability in metallic fuel elements under conditions of high fuel burnup led in the 1960s to the virtual worldwide choice of ceramic fuels. Although ceramic fuels provide lower breeding performance, this objective is no longer an important consideration in most national programs. Mixed uranium and plutonium dioxide became the ceramic fuel that has received the widest use. The more advanced ceramic fuels, mixed uranium and plutonium carbides and nitrides, continue under development. More recently, metal fuel elements of improved design have joined ceramic fuels in achieving goal burnups of 15 to 20 percent. Low-swelling fuel cladding alloys have also been continuously developed to deal with the unexpected problem of void formation in stainless steels subjected to fast neutron irradiation, a phenomenon first observed in the 1960s.

  19. Nanostructure of metallic particles in light water reactor used nuclear fuel

    NASA Astrophysics Data System (ADS)

    Buck, Edgar C.; Mausolf, Edward J.; McNamara, Bruce K.; Soderquist, Chuck Z.; Schwantes, Jon M.

    2015-06-01

    An extraordinary nano-structure has been observed in the metallic (Mo-Tc-Ru-Rh-Pd) particles that are known to form during irradiated in light water nuclear reactor fuels. This structure points possible high catalytic reactivity through the occurrence of a very high surface area as well as defect sites. We have analyzed separated metallic particles from dissolved high burn-up spent nuclear fuel using scanning and transmission electron microscopy. The larger particles vary in diameter between ∼10 and ∼300 nm and possess a hexagonally close packed epsilon-ruthenium structure. These particles are not always single crystals but often consist of much smaller crystallites on the order of 1-3 nm in diameter with evidence suggesting the occurrence of some amorphous regions. It is possible that neutron irradiation and fission product recoils generated the unusual small crystallite size. The composition of the metallic particles was variable with low levels of uranium present in some of the particles. We hypothesize that the uranium may have induced the formation of the amorphous (or frustrated) metal structure. This unique nano-structure may play an important role in the environmental behavior of nuclear fuels.

  20. REFORMULATION OF COAL-DERIVED TRANSPORTATION FUELS: SELECTIVE OXIDATION OF CARBON MONOXIDE ON METAL FOAM CATALYSTS

    SciTech Connect

    Paul Chin; Xiaolei Sun; George W. Roberts; Amornmart Sirijarhuphan; Sourabh Pansare; James G. Goodwin Jr; Richard W. Rice; James J. Spivey

    2005-06-01

    Hydrocarbon fuels must be reformed in a series of steps to provide hydrogen for use in proton exchange membrane fuel cells (PEMFCs). Preferential oxidation (PROX) is one method to reduce the CO concentration to less than 10 ppm in the presence of {approx}40% H{sub 2}, CO{sub 2}, and steam. This will prevent CO poisoning of the PEMFC anode. Structured supports, such as ceramic monoliths, can be used for the PROX reaction. Alternatively, metal foams offer a number of advantages over the traditional ceramic monolith.

  1. Application of fuel cell for pyrite and heavy metal containing mining waste

    NASA Astrophysics Data System (ADS)

    Keum, H.; Ju, W. J.; Jho, E. H.; Nam, K.

    2015-12-01

    Once pyrite and heavy metal containing mining waste reacts with water and air it produces acid mine drainage (AMD) and leads to the other environmental problems such as contamination of surrounding soils. Pyrite is the major source of AMD and it can be controlled using a biological-electrochemical dissolution method. By enhancing the dissolution of pyrite using fuel cell technology, not only mining waste be beneficially utilized but also be treated at the same time by. As pyrite-containing mining waste is oxidized in the anode of the fuel cell, electrons and protons are generated, and electrons moves through an external load to cathode reducing oxygen to water while protons migrate to cathode through a proton exchange membrane. Iron-oxidizing bacteria such as Acidithiobacillus ferrooxidans, which can utilize Fe as an electron donor promotes pyrite dissolution and hence enhances electrochemical dissolution of pyrite from mining waste. In this study mining waste from a zinc mine in Korea containing 17 wt% pyrite and 9% As was utilized as a fuel for the fuel cell inoculated with A. ferrooxidans. Electrochemically dissolved As content and chemically dissolved As content was compared. With the initial pH of 3.5 at 23℃, the dissolved As concentration increased (from 4.0 to 13 mg/L after 20 d) in the fuel cell, while it kept decreased in the chemical reactor (from 12 to 0.43 mg/L after 20 d). The fuel cell produced 0.09 V of open circuit voltage with the maximum power density of 0.84 mW/m2. Dissolution of As from mining waste was enhanced through electrochemical reaction. Application of fuel cell technology is a novel treatment method for pyrite and heavy metals containing mining waste, and this method is beneficial for mining environment as well as local community of mining areas.

  2. Metallic Nickel Hydroxide Nanosheets Give Superior Electrocatalytic Oxidation of Urea for Fuel Cells.

    PubMed

    Zhu, Xiaojiao; Dou, Xinyu; Dai, Jun; An, Xingda; Guo, Yuqiao; Zhang, Lidong; Tao, Shi; Zhao, Jiyin; Chu, Wangsheng; Zeng, Xiao Cheng; Wu, Changzheng; Xie, Yi

    2016-09-26

    The direct urea fuel cell (DUFC) is an important but challenging renewable energy production technology, it offers great promise for energy-sustainable developments and mitigating water contamination. However, DUFCs still suffer from the sluggish kinetics of the urea oxidation reaction (UOR) owing to a 6 e(-) transfer process, which poses a severe hindrance to their practical use. Herein, taking β-Ni(OH)2 nanosheets as the proof-of-concept study, we demonstrated a surface-chemistry strategy to achieve metallic Ni(OH)2 nanosheets by engineering their electronic structure, representing a first metallic configuration of transition-metal hydroxides. Surface sulfur incorporation successfully brings synergetic effects of more exposed active sites, good wetting behavior, and effective electron transport, giving rise to greatly enhanced performance for UOR. Metallic nanosheets exhibited a much higher current density, smaller onset potential and stronger durability. PMID:27572334

  3. Metallic Nickel Hydroxide Nanosheets Give Superior Electrocatalytic Oxidation of Urea for Fuel Cells.

    PubMed

    Zhu, Xiaojiao; Dou, Xinyu; Dai, Jun; An, Xingda; Guo, Yuqiao; Zhang, Lidong; Tao, Shi; Zhao, Jiyin; Chu, Wangsheng; Zeng, Xiao Cheng; Wu, Changzheng; Xie, Yi

    2016-09-26

    The direct urea fuel cell (DUFC) is an important but challenging renewable energy production technology, it offers great promise for energy-sustainable developments and mitigating water contamination. However, DUFCs still suffer from the sluggish kinetics of the urea oxidation reaction (UOR) owing to a 6 e(-) transfer process, which poses a severe hindrance to their practical use. Herein, taking β-Ni(OH)2 nanosheets as the proof-of-concept study, we demonstrated a surface-chemistry strategy to achieve metallic Ni(OH)2 nanosheets by engineering their electronic structure, representing a first metallic configuration of transition-metal hydroxides. Surface sulfur incorporation successfully brings synergetic effects of more exposed active sites, good wetting behavior, and effective electron transport, giving rise to greatly enhanced performance for UOR. Metallic nanosheets exhibited a much higher current density, smaller onset potential and stronger durability.

  4. Metal hydride and pyrophoric fuel additives for dicyclopentadiene based hybrid propellants

    NASA Astrophysics Data System (ADS)

    Shark, Steven C.

    The purpose of this study is to investigate the use of reactive energetic fuel additives that have the potential to increase the combustion performance of hybrid rocket propellants in terms of solid fuel regression rate and combustion efficiency. Additives that can augment the combustion flame zone in a hybrid rocket motor by means of increased energy feedback to the fuel grain surface are of great interest. Metal hydrides have large volumetric hydrogen densities, which gives these materials high performance potential as fuel additives in terms of specifc impulse. The excess hydrogen and corresponding base metal may also cause an increase in the hybrid rocket solid fuel regression rate. Pyrophoric additives also have potential to increase the solid fuel regression rate by reacting more readily near the burning fuel surface providing rapid energy feedback. An experimental performance evaluation of metal hydride fuel additives for hybrid rocket motor propulsion systems is examined in this study. Hypergolic ignition droplet tests and an accelerated aging study revealed the protection capabilities of Dicyclopentadiene (DCPD) as a fuel binder, and the ability for unaided ignition. Static hybrid rocket motor experiments were conducted using DCPD as the fuel. Sodium borohydride (NabH4) and aluminum hydride (AlH3) were examined as fuel additives. Ninety percent rocket grade hydrogen peroxide (RGHP) was used as the oxidizer. In this study, the sensitivity of solid fuel regression rate and characteristic velocity (C*) efficiency to total fuel grain port mass flux and particle loading is examined. These results were compared to HTPB combustion performance as a baseline. Chamber pressure histories revealed steady motor operation in most tests, with reduced ignition delays when using NabH4 as a fuel additive. The addition of NabH4 and AlH3 produced up to a 47% and 85% increase in regression rate over neat DCPD, respectively. For all test conditions examined C* efficiency ranges

  5. Conversion of light hydrocarbon gases to metal carbides for production of liquid fuels and chemicals

    SciTech Connect

    Diaz, A.F.; Modestino, A.J.; Howard, J.B.; Peters, W.A.

    1993-02-01

    Light hydrocarbon gases could be reacted with low cost alkaline earth metal oxide (CaO, MgO) in high-temperature plasma reactor to achieve very high ([le]100%) gas conversion to H[sub 2], CO, and the corresponding metal carbides. These carbides could be stored, transported, and hydrolyzed to acetylene or methyl acetylene, which in turn could be upgraded to a wide range of chemicals and premium liquid hydrocarbon fuels. An electric arc discharge reactor was built for converting methane. Literature reviews were made.

  6. Actinides in metallic waste from electrometallurgical treatment of spent nuclear fuel

    NASA Astrophysics Data System (ADS)

    Janney, D. E.; Keiser, D. D.

    2003-09-01

    Argonne National Laboratory has developed a pyroprocessing-based technique for conditioning spent sodium-bonded nuclear-reactor fuel in preparation for long-term disposal. The technique produces a metallic waste form whose nominal composition is stainless steel with 15 wt.% Zr (SS-15Zr), up to ˜ 11 wt.% actinide elements (primarily uranium), and a few percent metallic fission products. Actual and simulated waste forms show similar eutectic microstructures with approximately equal proportions of iron solid solution phases and Fe-Zr intermetallics. This article reports on an analysis of simulated waste forms containing uranium, neptunium, and plutonium.

  7. A Study of Fast Reactor Fuel Transmutation in a Candidate Dispersion Fuel Design

    SciTech Connect

    Mark DeHart; Hongbin Zhang; Eric Shaber; Matthew Jesse

    2010-11-01

    Dispersion fuels represent a significant departure from typical ceramic fuels to address swelling and radiation damage in high burnup fuel. Such fuels use a manufacturing process in which fuel particles are encapsulated within a non-fuel matrix. Dispersion fuels have been studied since 1997 as part of an international effort to develop and test very high density fuel types for the Reduced Enrichment for Research and Test Reactors (RERTR) program.[1] The Idaho National Laboratory is performing research in the development of an innovative dispersion fuel concept that will meet the challenges of transuranic (TRU) transmutation by providing an integral fission gas plenum within the fuel itself, to eliminate the swelling that accompanies the irradiation of TRU. In this process, a metal TRU vector produced in a separations process is atomized into solid microspheres. The dispersion fuel process overcoats the microspheres with a mixture of resin and hollow carbon microspheres to create a TRUC. The foam may then be heated and mixed with a metal power (e.g., Zr, Ti, or Si) and resin to form a matrix metal carbide, that may be compacted and extruded into fuel elements. In this paper, we perform reactor physics calculations for a core loaded with the conceptual fuel design. We will assume a “typical” TRU vector and a reference matrix density. We will employ a fuel and core design based on the Advanced Burner Test Reactor (ABTR) design.[2] Using the CSAS6 and TRITON modules of the SCALE system [3] for preliminary scoping studies, we will demonstrate the feasibility of reactor operations. This paper will describe the results of these analyses.

  8. Tubular solid oxide fuel cells with porous metal supports and ceramic interconnections

    SciTech Connect

    Huang, Kevin; Ruka, Roswell J.

    2012-05-08

    An intermediate temperature solid oxide fuel cell structure capable of operating at from 600.degree. C. to 800.degree. C. having a very thin porous hollow elongated metallic support tube having a thickness from 0.10 mm to 1.0 mm, preferably 0.10 mm to 0.35 mm, a porosity of from 25 vol. % to 50 vol. % and a tensile strength from 700 GPa to 900 GPa, which metallic tube supports a reduced thickness air electrode having a thickness from 0.010 mm to 0.2 mm, a solid oxide electrolyte, a cermet fuel electrode, a ceramic interconnection and an electrically conductive cell to cell contact layer.

  9. Fabrication of metallic bipolar plate for proton exchange membrane fuel cells by rubber pad forming

    NASA Astrophysics Data System (ADS)

    Liu, Yanxiong; Hua, Lin

    In this paper, the rubber pad forming process is used to fabricate the metallic bipolar plate for a proton exchange membrane (PEM) fuel cell, which has multi-array micro-scale flow channels on its surface. The rubber pad forming process has the following advantages: high surface quality and dimensional accuracy of the formed parts, low cost of the die because only one rigid die is required, and high efficiency. The process control parameters (rubber hardness, internal and outer radii, draft angle) of the rubber pad forming are analyzed by the finite element method using the commercial software Abaqus. After that, the rubber pad forming process is used to manufacture a metallic bipolar plate of SS304 stainless steel with perfect flow micro-channels. The results of this effort indicated that the rubber pad forming process is a feasible technique for fabricating the bipolar plates of PEM fuel cells.

  10. In situ ceramic layer growth on coated fuel particles dispersed in a zirconium metal matrix

    SciTech Connect

    Terrani, Kurt A; Silva, G W Chinthaka M; Kiggans, Jim; Cai, Zhonghou; Shin, Dongwon; Snead, Lance Lewis

    2013-01-01

    The extent and nature of the chemical interaction between the outermost coating layer of coated fuel particles embedded in zirconium metal during fabrication of metal matrix microencapsulated fuels was examined. Various particles with outermost coating layers of pyrocarbon, SiC, and ZrC have been investigated in this study. ZrC-Zr interaction was least substantial while PyC-Zr reaction can be exploited to produce a ZrC layer at the interface in an in situ manner. The thickness of the ZrC layer in the latter case can be controlled by adjusting the time and temperature during processing. The kinetics of ZrC layer growth is significantly faster from what is predicted using literature carbon diffusivity data in ZrC. SiC-Zr interaction is more complex and results in formation of various chemical phases in a layered aggregate morphology at the interface.

  11. In situ ceramic layer growth on coated fuel particles dispersed in a zirconium metal matrix

    NASA Astrophysics Data System (ADS)

    Terrani, K. A.; Silva, C. M.; Kiggans, J. O.; Cai, Z.; Shin, D.; Snead, L. L.

    2013-06-01

    The extent and nature of the chemical interaction between the outermost coating layer of coated fuel particles embedded in zirconium metal during fabrication of metal matrix microencapsulated fuels were examined. Various particles with outermost coating layers of pyrocarbon, SiC, and ZrC have been investigated in this study. ZrC-Zr interaction was the least substantial, while the PyC-Zr reaction can be exploited to produce a ZrC layer at the interface in an in situ manner. The thickness of the ZrC layer in the latter case can be controlled by adjusting the time and temperature during processing. The kinetics of ZrC layer growth is significantly faster from what is predicted using literature carbon diffusivity data in ZrC. SiC-Zr interaction is more complex and results in formation of various chemical phases in a layered aggregate morphology at the interface.

  12. Engineering-Scale Development of Injection Casting Technology for Metal Fuel Cycle

    SciTech Connect

    Ogata, Takanari; Tsukada, Takeshi

    2007-07-01

    Engineering-scale injection casting tests were conducted in order to demonstrate the applicability of injection casting technology to the commercialized fast reactor fuel cycle. The uranium-zirconium alloy slugs produced in the tests were examined with reference to the practical slug specifications: average diameter tolerance {+-} 0.05 mm, local diameter tolerance {+-} 0.1 mm, density range 15.3 to 16.1 g/cm{sup 3}, zirconium content range 10 {+-} 1 wt% and total impurity (C, N, O, Si) <2000 ppm, which were provisionally determined. Most of the slugs satisfied these specifications, except for zirconium content. The impurity level was sufficiently low even though the residual and scrapped alloys were repeatedly recycled. The weight ratio of injected metal to charged metal was sufficiently high for a high process throughput. The injection casting technology will be applicable to the commercialized fuel cycle when the issue of zirconium content variation is resolved. (authors)

  13. Laboratory studies of shear/leach processing of zircaloy clad metallic uranium reactor fuel

    SciTech Connect

    Swanson, J.L.; Bray, L.A.; Kjarmo, H.E.; Ryan, J.L.; Matsuzaki, C.L.; Pitman, S.G.; Haberman, J.H.

    1985-12-01

    The safety aspects addressed centered on understanding and explaining the undesirable reactions, ''fires,'' observed in a few instances during earlier processing of such fuel at the Nuclear Fuels Services (NFS) plant at West Valley, New York. Consideration of the dissolver fires that occurred at NFS leads to the conclusion that they resulted from rapid reactions with uranium metal, rather than with zirconium metal or with sensitized weld beads. The fires observed at NFS during hulls handling operations may have involved sensitized weld beads as suggested by earlier investigators, but current results suggest that these fires also could have been caused by reactions involving uranium metal. Very little pyrophoric activity was observed in leeached cladding hulls, indicating a very low probability for safety problems resulting from the U-Zr intermetallic zone in N-Reactor fuel. Consideration of the potential role of hydrides in the fires observed at NFS indicates that they were also not important factors. Consideration was also given to protective atmospheres to be used during shearing to prevent excessive reaction during that operation. A water deluge during shearing will likely provide adequate safety while meshing well with other process considerations. Studies on the dissolution of metallic uranium in nitric acid show an initial slower reaction followed by a faster reaction that proceeds at a sustained rate for a prolonged period of time. At solution concentrations typical of those encountered in practical uranium dissolver conditions, this sustained rate is governed by an equation such as: Dissolution rate = K (surface area) ((HNO3)+2(U))/sup 2.6/. Little difference was found in dissolution rates of as-fabricated and of irradiated fuel. The transuranic element content of leached cladding hulls was found to be approx. 400 nCi/g. This is too high to allow disposal as low-level waste.

  14. Inherent safety phenomenon of fission-gas induced axial extrusion in oxide and metal fueled LMFBRs

    SciTech Connect

    Miles, K.J.; Kalimullah

    1985-01-01

    The current emphasis in LMFBR design is to develop reactor systems that contain as many features as possible to limit the severity of hypothetical accidents and provide the maximum time before corrective action is required while maintaining low capital costs. One feature is the possibility of fission-gas induced axial extrusion of the fuel within the intact cladding. The potential exists for this phenomenon to enable the reactor to withstand most accidents of the TOP variety, or at least provide an extended time for corrective action to be taken. Under transient conditions which produce a heating of the fuel above its nominal operating temperature, thermal expansion of the material axially produces a negative reactivity effect. This effect is presently considered in most accident analysis codes. The phenomenon of fission-gas induced axial extrusion has received renewed interest because of the consideration of metal alloys of uranium and plutonium for the fuel in some current reactor designs.

  15. Development of new ferritic steels as cladding material for metallic fuel fast breeder reactor

    NASA Astrophysics Data System (ADS)

    Tokiwai, Moriyasu; Horie, Masaaki; Kako, Kenji; Fujiwara, Masayuki

    1993-09-01

    The excellent thermal, chemical and neutronic properties of metallic fuel (U-Pu-Zr alloy) will lead to drastic improvements in fast reactor safety and the related fuel cycle economy. Some new high molybdenum 12Cr ferritic stainless steel candidate cladding alloys have been designed to achieve the mechanical properties required for high performance metallic fuel elements. These candidate claddings were irradiated by ion bombardment and tested to determine their strength and creep rupture properties. A 12Cr-8Mo and a 12Cr-8Mo-0.1Y 2O 3 steel were fabricated into cladding via a powder metallurgy process and by a mechanical alloying process, respectively. These claddings had two and three times the creep rupture strength (pressurized at 650°C for 10000 h) of a conventional 12Cr ferritic steel (HT-9). These two steels also showed no void formation up to 350 dpa by Ni 3+ irradiation. A zircaloy-2 lined steel cladding tube has also been fabricated for the purpose of reducing fuel-cladding interdiffusion and chemical interaction.

  16. A Metal Fuel Core Concept for 1000 MWt Advanced Burner Reactor

    SciTech Connect

    Yang, W.S.; Kim, T.K.; Grandy, C.

    2007-07-01

    This paper describes the core design and performance characteristics of a metal fuel core concept for a 1000 MWt Advanced Burner Reactor. A ternary metal fuel form of U-TRU-Zr was assumed with weapons grade plutonium feed for the startup core and TRU recovered from LWR spent fuel for the recycled equilibrium core. A compact burner core was developed by trade-off between the burnup reactivity loss and TRU conversion ratio, with a fixed cycle length of one-year. In the startup core, the average TRU enrichment is 15.5%, the TRU conversion ratio is 0.81, and the burnup reactivity loss over a cycle is 3.6% {delta}k. The heavy metal and TRU inventories are 13.1 and 2.0 metric tons, respectively. The average discharge burnup is 93 MWd/kg, and the TRU consumption rate is 55.5 kg/year. For the recycled equilibrium core, the average TRU enrichment is 22.1 %, the TRU conversion ratio is 0.73, and the burnup reactivity loss is 2.2% {delta}k. The TRU inventory and consumption rate are 2.9 metric tons and 81.6 kg/year, respectively. The evaluated reactivity coefficients provide sufficient negative feedbacks. The control systems provide shutdown margins that are more than adequate. The integral reactivity parameters for quasi-static reactivity balance analysis indicate favorable passive safety features, although detailed safety analyses are required to verify passive safety behavior. (authors)

  17. Method for removal of heavy metal from molten salt in IFR fuel pyroprocessing

    SciTech Connect

    Gay, E.C.; Miller, W.E.; Laidler, J.J.

    1994-02-01

    This report details the pyrometallurgical process for recycling spent metal fuels from the Integral Fast Reactor (IFR) which involves electrorefining spent fuel in a molten salt electrolyte (LiCl-KCI-U/PuCl{sub 3}) at 500{degree}C. The total heavy metal chloride concentration in the salt will be about 2 mol %. At some point, the concentrations of alkali, alkaline earth, and rare earth fission products in the salt must be reduced to lower the amount of heat generated in the electrorefiner. The heavy metal concentration in the salt must be reduced before removing the fission products from the salt. The operation uses a lithium-cadmium alloy anode that is solid at 500{degree}C, a solid mandrel cathode with a ceramic catch crucible below to collect heavy metal that falls off it, and a liquid cadmium cathode. The design criteria that had to be met by this equipment included the following: (1) control of the reduction rate by lithium, (2) good separation between heavy metal and rare earths, and (3) the capability to collect heavy metal and rare earths over a wide range of salt compositions. In tests conducted in an engineering-scale electrorefiner (10 kg uranium per cathode), good separation was achieved while removing uranium and rare earths from the salt. Only 13% of the rare earths was removed, while 99.9% of the uranium in the salt was removed; subsequently, the rare earths were also reduced to low concentrations. The uranium concentration in the salt was reduced to 0.05 ppm after uranium and rare earths were transferred from the salt to a solid mandrel cathode with a catch crucible. Rare earth concentrations in the salt were reduced to less than 0.01 wt % in these operations. Similar tests are planned to remove plutonium from the salt in a laboratory-scale (100--300 g heavy metal) electrorefiner.

  18. Low Emissions Burner Technology for Metal Processing Industry using Byproducts and Biomass Derived Liquid Fuels

    SciTech Connect

    Agrawal, Ajay; Taylor, Robert

    2013-09-30

    path forward to utilize both fossil and alternative liquid fuels in the same combustion system. In particular, experiments show that straight VO can be cleanly combusted without the need for chemical processing or preheating steps, which can result in significant economic and environmental benefits. Next, low-emission combustion of glycerol/methane was achieved by utilizing FB injector to yield fine droplets of highly viscous glycerol. Heat released from methane combustion further improves glycerol pre-vaporization and thus its clean combustion. Methane addition results in an intensified reaction zone with locally high temperatures near the injector exit. Reduction in methane flow rate elongates the reaction zone, which leads to higher CO emissions and lower NOx emissions. Similarly, higher air to liquid (ALR) mass ratio improves atomization and fuel pre-vaporization and shifts the flame closer to the injector exit. In spite of these internal variations, all fuel mixes of glycerol with methane produced similar CO and NOx emissions at the combustor exit. Results show that FB concept provides low emissions with the flexibility to utilize gaseous and highly viscous liquid fuels, straight VO and glycerol, without preheating or preprocessing the fuels. Following these initial experiments in quartz combustor, we demonstrated that glycerol combustion can be stably sustained in a metal combustor. Phase Doppler Particle Analyzer (PDPA) measurements in glycerol/methane flames resulted in flow-weighted Sauter Mean Diameter (SMD) of 35 to 40 μm, depending upon the methane percentage. This study verified that lab-scale dual-fuel burner using FB injector can successfully atomize and combust glycerol and presumably other highly viscous liquid fuels at relatively low HRR (<10 kW). For industrial applications, a scaled-up glycerol burner design thus seemed feasible.

  19. Facile and Gram-scale Synthesis of Metal-free Catalysts: Toward Realistic Applications for Fuel Cells

    PubMed Central

    Kim, Ok-Hee; Cho, Yong-Hun; Chung, Dong Young; Kim, Min Jeong; Yoo, Ji Mun; Park, Ji Eun; Choe, Heeman; Sung, Yung-Eun

    2015-01-01

    Although numerous reports on nonprecious metal catalysts for replacing expensive Pt-based catalysts have been published, few of these studies have demonstrated their practical application in fuel cells. In this work, we report graphitic carbon nitride and carbon nanofiber hybrid materials synthesized by a facile and gram-scale method via liquid-based reactions, without the use of toxic materials or a high pressure-high temperature reactor, for use as fuel cell cathodes. The resulting materials exhibited remarkable methanol tolerance, selectivity, and stability even without a metal dopant. Furthermore, these completely metal-free catalysts exhibited outstanding performance as cathode materials in an actual fuel cell device: a membrane electrode assembly with both acidic and alkaline polymer electrolytes. The fabrication method and remarkable performance of the single cell produced in this study represent progressive steps toward the realistic application of metal-free cathode electrocatalysts in fuel cells. PMID:25728910

  20. Facile and Gram-scale Synthesis of Metal-free Catalysts: Toward Realistic Applications for Fuel Cells

    NASA Astrophysics Data System (ADS)

    Kim, Ok-Hee; Cho, Yong-Hun; Chung, Dong Young; Kim, Min Jeong; Yoo, Ji Mun; Park, Ji Eun; Choe, Heeman; Sung, Yung-Eun

    2015-03-01

    Although numerous reports on nonprecious metal catalysts for replacing expensive Pt-based catalysts have been published, few of these studies have demonstrated their practical application in fuel cells. In this work, we report graphitic carbon nitride and carbon nanofiber hybrid materials synthesized by a facile and gram-scale method via liquid-based reactions, without the use of toxic materials or a high pressure-high temperature reactor, for use as fuel cell cathodes. The resulting materials exhibited remarkable methanol tolerance, selectivity, and stability even without a metal dopant. Furthermore, these completely metal-free catalysts exhibited outstanding performance as cathode materials in an actual fuel cell device: a membrane electrode assembly with both acidic and alkaline polymer electrolytes. The fabrication method and remarkable performance of the single cell produced in this study represent progressive steps toward the realistic application of metal-free cathode electrocatalysts in fuel cells.

  1. Facile and gram-scale synthesis of metal-free catalysts: toward realistic applications for fuel cells.

    PubMed

    Kim, Ok-Hee; Cho, Yong-Hun; Chung, Dong Young; Kim, Min Jeong; Yoo, Ji Mun; Park, Ji Eun; Choe, Heeman; Sung, Yung-Eun

    2015-03-02

    Although numerous reports on nonprecious metal catalysts for replacing expensive Pt-based catalysts have been published, few of these studies have demonstrated their practical application in fuel cells. In this work, we report graphitic carbon nitride and carbon nanofiber hybrid materials synthesized by a facile and gram-scale method via liquid-based reactions, without the use of toxic materials or a high pressure-high temperature reactor, for use as fuel cell cathodes. The resulting materials exhibited remarkable methanol tolerance, selectivity, and stability even without a metal dopant. Furthermore, these completely metal-free catalysts exhibited outstanding performance as cathode materials in an actual fuel cell device: a membrane electrode assembly with both acidic and alkaline polymer electrolytes. The fabrication method and remarkable performance of the single cell produced in this study represent progressive steps toward the realistic application of metal-free cathode electrocatalysts in fuel cells.

  2. Processing of mixed uranium/refractory metal carbide fuels for high temperature space nuclear reactors

    NASA Astrophysics Data System (ADS)

    Knight, Travis; Anghaie, Samim

    2000-01-01

    Single phase, solid-solution mixed uranium/refractory metal carbides have been proposed as an advanced nuclear fuel for high performance, next generation space power and propulsion systems. These mixed carbides such as the pseudo-ternary, (U, Zr, Nb)C, hold significant promise because of their high melting points (typically greater than 3200 K), thermochemical stability in a hot hydrogen environment, and high thermal conductivity. However, insufficient test data exist under nuclear thermal propulsion conditions of temperature and hot hydrogen environment to fully evaluate their performance. Various compositions of (U, Zr, Nb)C were processed with 5% and 10% metal mole fraction of uranium. Stoichiometric samples were processed from the constituent carbide powders while hypostoichiometric samples with carbon-to-metal (C/M) ratios of 0.95 were processed from uranium hydride, graphite, and constituent refractory carbide powders. Processing techniques of cold pressing, sintering, and hot pressing were investigated to optimize the processing parameters necessary to produce dense (low porosity), homogeneous, single phase, solid-solution mixed carbide nuclear fuels for testing. This investigation was undertaken to evaluate and characterize the performance of these mixed uranium/refractory metal carbides for space power and propulsion applications. .

  3. The Potential of Aluminium Metal Powder as a Fuel for Space Propulsion Systems

    NASA Astrophysics Data System (ADS)

    Ismail, A. M.; Osborne, B.; Welch, C. S.

    Metal powder propulsion systems have been addressed intermittently since the Second World War, initially in the field of underwater propulsion where research in the application of propelling torpedoes continues until this day. During the post war era, researchers attempted to utilise metal powders as a fuel for ram jet applications in missiles. The 1960's and 1970's saw additional interest in the use of `pure powder' propellants, i.e. fluidised metal fuel and oxidiser, both in solid particulate form. Again the application was for employment in space-constrained missiles where the idea was to maximise the performance of high energy density powder propellants in order to enhance the missile's flight duration. Metal powder as possible fuel was investigated for in-situ resource utilisation propulsion systems post-1980's where the emphasis was on the use of gaseous oxygen or liquid oxygen combined with aluminium metal powder for use as a ``lunar soil propellant'' or carbon dioxide and magnesium metal powder as a ``Martian propellant''.Albeit aluminium metal powder propellants are lower in performance than cryogenic and Earth storable propellants, the former does have an advantage inasmuch that the propulsion system is generic, i.e. it can be powered with chemicals mined and processed on Earth, the Moon and Mars. Thus, due to the potential refuelling capability, the lower performing aluminium metal powder propellant would effectively possess a much higher change in velocity (V) for multiple missions than the cryogenic or Earth storable propellant which is only suitable for one planet or one mission scenario, respectively.One of the principal limitations of long duration human spaceflight beyond cis-lunar orbit is the lack of refuelling capabilities on distant planets resulting in the reliance on con- ventional non-cryogenic, propellants produced on Earth. If one could develop a reliable propulsion system operating on pro- pellants derived entirely of ingredients found on

  4. Separation and Recovery of Uranium Metal from Spent Light Water Reactor Fuel via Electrolytic Reduction and Electrorefining

    SciTech Connect

    S. D. Herrmann; S. X. Li

    2010-09-01

    A series of bench-scale experiments was performed in a hot cell at Idaho National Laboratory to demonstrate the separation and recovery of uranium metal from spent light water reactor (LWR) oxide fuel. The experiments involved crushing spent LWR fuel to particulate and separating it from its cladding. Oxide fuel particulate was then converted to metal in a series of six electrolytic reduction runs that were performed in succession with a single salt loading of molten LiCl – 1 wt% Li2O at 650 °C. Analysis of salt samples following the series of electrolytic reduction runs identified the diffusion of select fission products from the spent fuel to the molten salt electrolyte. The extents of metal oxide conversion in the post-test fuel were also quantified, including a nominal 99.7% conversion of uranium oxide to metal. Uranium metal was then separated from the reduced LWR fuel in a series of six electrorefining runs that were performed in succession with a single salt loading of molten LiCl-KCl-UCl3 at 500 °C. Analysis of salt samples following the series of electrorefining runs identified additional partitioning of fission products into the molten salt electrolyte. Analyses of the separated uranium metal were performed, and its decontamination factors were determined.

  5. Metal decoration of exfoliated graphite nanoplatelets (xGnP) for fuel cell application

    NASA Astrophysics Data System (ADS)

    Do, In-Hwan

    The synthesis and characterization of metal particles at nanometer length scale has been the object of much research in modern nanotechnology due to their great impact on new nanoscale scientific and technological applications. Nanoscale metal particles possess unique optical, thermal, electronic, magnetic properties and chemical reactivity since the size of the resulting materials is on the same order as the fundamental interaction distances that give rise to physical properties and thus shows the quantum size effect which is not observed in their bulky status. Therefore, an effective synthetic method is required to obtain uniform small metal powders with controlled size and a narrow size distribution and also to produce nanocomposites consisting of either metals or metal oxides supported on carbons or metals dispersed on metal oxides for a variety of applications in chemical industries, automobiles, energy and power generating devices, hydrogen economy as well as for sensors. On the other hand, although their excellent mechanical, thermal and electrical conductivity, excellent corrosion and oxidation resistance, and low impurity levels which are required as a breakthrough material to increase performance of next generation energy devices, exfoliated graphite nanoplatelet (xGnP) has not been studied as deeply as recent new nano structured carbon materials such as single wall carbon nanotubes (SWNT), multi-wall carbon nanotubes (MWNT), carbon nanohorn (CNH), graphite nanofiber (GNF), and fullerenes. In addition, xGnP is much cost-effective compared to other carbon nanostructures. Hence, it is interesting to evaluate the applicability of xGnP as a support material for fuel cell which is one of promising energy devices for the future. In this research, a new simple, efficient and economic way is presented for the synthesis of noble metal nanoparticles such as Pt, Ru, Pd, etc and their deposition on various carbon supports and metal oxides via microwave heating in the

  6. Performance evaluation and characterization of metallic bipolar plates in a proton exchange membrane (PEM) fuel cell

    NASA Astrophysics Data System (ADS)

    Hung, Yue

    Bipolar plate and membrane electrode assembly (MEA) are the two most repeated components of a proton exchange membrane (PEM) fuel cell stack. Bipolar plates comprise more than 60% of the weight and account for 30% of the total cost of a fuel cell stack. The bipolar plates perform as current conductors between cells, provide conduits for reactant gases, facilitate water and thermal management through the cell, and constitute the backbone of a power stack. In addition, bipolar plates must have excellent corrosion resistance to withstand the highly corrosive environment inside the fuel cell, and they must maintain low interfacial contact resistance throughout the operation to achieve optimum power density output. Currently, commercial bipolar plates are made of graphite composites because of their relatively low interfacial contact resistance (ICR) and high corrosion resistance. However, graphite composite's manufacturability, permeability, and durability for shock and vibration are unfavorable in comparison to metals. Therefore, metals have been considered as a replacement material for graphite composite bipolar plates. Since bipolar plates must possess the combined advantages of both metals and graphite composites in the fuel cell technology, various methods and techniques are being developed to combat metallic corrosion and eliminate the passive layer formed on the metal surface that causes unacceptable power reduction and possible fouling of the catalyst and the electrolyte. The main objective of this study was to explore the possibility of producing efficient, cost-effective and durable metallic bipolar plates that were capable of functioning in the highly corrosive fuel cell environment. Bulk materials such as Poco graphite, graphite composite, SS310, SS316, incoloy 800, titanium carbide and zirconium carbide were investigated as potential bipolar plate materials. In this work, different alloys and compositions of chromium carbide coatings on aluminum and SS316

  7. Metal foams application to enhance cooling of open cathode polymer electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Sajid Hossain, Mohammad; Shabani, Bahman

    2015-11-01

    Conventional channel flow fields of open cathode Polymer Electrolyte Membrane Fuel Cells (PEMFCs) introduce some challenges linked to humidity, temperature, pressure and oxygen concentration gradients along the conventional flow fields that reduce the cell performance. According to previous experimental reports, with conventional air flow fields, hotspot formation due to water accumulation in Gas Diffusion Layer (GDL) is common. Unlike continuous long flow passages in conventional channels, metal foams provide randomly interrupted flow passages. Re-circulation of fluid, due to randomly distributed tortuous ligaments, enhances temperature and humidity uniformity in the fluid. Moreover, the higher electrical conductivity of metal foams compared to non-metal current collectors and their very low mass density compared to solid metal materials are expected to increase the electrical performance of the cell while significantly reducing its weight. This article reviews the existing cooling systems and identifies the important parameters on the basis of reported literature in the air cooling systems of PEMFCs. This is followed by investigating metal foams as a possible option to be used within the structure of such PEMFCs as an option that can potentially address cooling and flow distribution challenges associated with using conventional flow channels, especially in air-cooled PEMFCs.

  8. Evaluation of Metal Halide, Plasma, and LED Lighting Technologies for a Hydrogen Fuel Cell Mobile Light (H 2 LT)

    DOE PAGES

    Miller, L. B.; Donohoe, S. P.; Jones, M. H.; White, W. A.; Klebanoff, L. E.; Velinsky, S. A.

    2015-04-22

    This article reports on the testing and comparison of a prototype hydrogen fuel cell light tower (H2LT) and a conventional diesel-powered metal halide light trailer for use in road maintenance and construction activities. The prototype was originally outfitted with plasma lights and then with light-emitting diode (LED) luminaires. Light output and distribution, lighting energy efficiency (i.e., efficacy), power source thermal efficiency, and fuel costs are compared. The metal halide luminaires have 2.2 and 3.1 times more light output than the plasma and LED luminaires, respectively, but they require more power/lumen to provide that output. The LED luminaires have 1.6 timesmore » better light efficacy than either the metal halide or plasma luminaires. The light uniformity ratios produced by the plasma and LED towers are acceptable. The fuel cell thermal efficiency at the power required to operate the plasma lights is 48%, significantly higher than the diesel generator efficiency of 23% when operating the metal halide lights. Due to the increased efficiency of the fuel cell and the LED lighting, the fuel cost per lumen-hour of the H2LT is 62% of the metal halide diesel light tower assuming a kilogram of hydrogen is twice the cost of a gallon of diesel fuel.« less

  9. Managing Chemotherapy Side Effects: Swelling (Fluid Retention)

    MedlinePlus

    ... ancer I nstitute Managing Chemotherapy Side Effects Swelling (Fluid retention) “My hands and feet were swollen and ... at one time. Managing Chemotherapy Side Effects: Swelling (Fluid retention) Weigh yourself. l Weigh yourself at the ...

  10. A combinatorial study on catalytic synergism in supported metal catalysts for fuel cell technology

    NASA Astrophysics Data System (ADS)

    Kobayashi, Tetsuhiko; Ueda, Atsushi; Yamada, Yusuke; Shioyama, Hiroshi

    2004-02-01

    In order to accelerate the catalyst development for the increasing demand on the fuel cell technology, it has been attempted to adopt a combinatorial approach. The catalytic synergism, often observed on the supported metal catalysts for the fuel cell utilization, has been subjected to study. It is proposed herein that not only a comparison of catalysts in one reaction, but also the comparison of interrelated reactions by use of a common catalyst library brings about important information to elucidate the catalytic synergism. Preliminary results of the comparison between the water-gas shift reaction and the steam reforming of MeOH on a given set of catalyst library are presented. An important indicator to predict the serendipitous synergism is expected to be obtained from such information by use of artificial intelligence.

  11. Cryogenic Gellant and Fuel Formulation for Metallized Gelled Propellants: Hydrocarbons and Hydrogen with Aluminum

    NASA Technical Reports Server (NTRS)

    Wong, Wing; Starkovich, John; Adams, Scott; Palaszewski, Bryan; Davison, William; Burt, William; Thridandam, Hareesh; Hu-Peng, Hsiao; Santy, Myrrl J.

    1994-01-01

    An experimental program to determine the viability of nanoparticulate gellant materials for gelled hydrocarbons and gelled liquid hydrogen was conducted. The gellants included alkoxides (BTMSE and BTMSH) and silica-based materials. Hexane, ethane, propane and hydrogen were gelled with the newly-formulated materials and their rheological properties were determined: shear stress versus shear rate and their attendant viscosities. Metallized hexane with aluminum particles was also rheologically characterized. The propellant and gellant formulations were selected for the very high surface area and relatively-high energy content of the gellants. These new gellants can therefore improve rocket engine specific impulse over that obtained with traditional cryogenic-fuel gellant materials silicon dioxide, frozen methane, or frozen ethane particles. Significant reductions in the total mass of the gellant were enabled in the fuels. In gelled liquid hydrogen, the total mass of gellant was reduced from 10-40 wt percent of frozen hydrocarbon particles to less that 8 wt percent with the alkoxide.

  12. SYNERESIS AND SWELLING OF GELATIN.

    PubMed

    Kunitz, M

    1928-11-20

    1. When solid blocks of isoelectric gelatin are placed in cold distilled water or dilute buffer of pH 4.7, only those of a gelatin content of more than 10 per cent swell, while those of a lower gelatin content not only do not swell but actually lose water. 2. The final quantity of water lost by blocks of dilute gelatin is the same whether the block is immersed in a large volume of water or whether syneresis has been initiated in the gel through mechanical forces such as shaking, pressure, etc., even in the absence of any outside liquid, thus showing that syneresis is identical with the process of negative swelling of dilute gels when placed in cold water, and may be used as a convenient term for it. 3. Acid- or alkali-containing gels give rise to greater syneresis than isoelectric gels, after the acid or alkali has been removed by dialysis. 4. Salt-containing gels show greater syneresis than salt-free gels of the same pH, after the salt has been washed away. 5. The acid and alkali and also the salt effect on syneresis of gels disappears at a gelatin concentration above 8 per cent. 6. The striking similarity in the behavior of gels with respect to syneresis and of gelatin solutions with respect to viscosity suggests the probability that both are due to the same mechanism, namely the mechanism of hydration of the micellae in gelatin by means of osmosis as brought about either by diffusible ions, as in the presence of acid or alkali, or by the soluble gelatin present in the micellae. The greater the pressures that caused swelling of the micellae while the gelatin was in the sol state, the greater is the loss of water from the gels when the pressures are removed. 7. A quantitative study of the loss of water by dilute gels of various gelatin content shows that the same laws which have been found by Northrop to hold for the swelling of gels of high concentrations apply also to the process of losing water by dilute gels, i.e. to the process of syneresis. The general

  13. Non-precious metal catalysis for proton-exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Leonard, Nathaniel Dean

    Non-precious metal catalysts (NPMC) for proton exchange membrane fuel cells (PEMFC) are explored. Research into NPMCs is motivated by the growing need for cleaner, more efficient energy options. NPMCs are one option to make fuel cells more commercially viable. To this end, the present work studies and simulates the morphology and function of metal-nitrogen-carbon (MNC) oxygen reduction catalysts. A porosity study finds that mesoporosity is critical to high performance of autogenic pressure metal-nitrogen-carbon (APMNC) oxygen reduction catalysts. Various carbon materials are used as precursors to synthesis APMNC catalysts. The catalysts and the associated porous carbon materials are characterized morphologically, chemically, and electrochemically. The results indicated that substrates adsorbing the most nitrogen and iron show the highest activity. Furthermore, a relationship is found between mesoporosity and nitrogen content indicating the importance of transport to active site creation. A correlation is found between surface alkalinity and catalytic activity for APMNC catalysts. The basic site strength and quantity were calculated by two different methods, and it was shown that increased Bronsted- Lowry basicity correlates to more active catalysts. The relationship between alkalinity and catalytic activity could be the result of the impact of alkalinity on the electron density of the metal centers or basic sites could encourage active site formation. It is found that the oxygen reduction reaction (ORR) proceeds both via a direct four-electron pathway to water at high potentials and an indirect peroxide pathway at low potentials on an APMNC catalyst. At higher potential, site availability inhibits peroxide generation causing the direct four-electron reduction pathway to dominate. Oxygen reduction begins to shift to the indirect peroxide pathway due to fast kinetics and higher site availability around 0.6 V vs RHE. The net peroxide generation remains relatively low

  14. Metal-Organic Frameworks for Removal of Xe and Kr from Nuclear Fuel Reprocessing Plants

    SciTech Connect

    Liu, Jian; Thallapally, Praveen K.; Strachan, Denis M.

    2012-08-07

    Removal of Xenon (Xe) and Krypton (Kr) from in parts per million (ppm) levels were demonstrated for the first time using two well known metal-organic frameworks (MOFs), HKUST-1 and Ni/DOBDC. Results of an activated carbon were also included for comparison. Ni/DOBDC has higher Xe/Kr selectivities than those of the activated carbon. Moreover, results show that the Ni/DOBDC and HKUST-1 can selectively adsorb Xe and Kr from air even at 1000 ppm concentration. This shows a promising future for MOFs in a radioactive nuclides separation from spent fuel.

  15. REFORMULATION OF COAL-DERIVED TRANSPORTATION FUELS: SELECTIVE OXIDATION OF CARBON MONOXIDE ON METAL FOAM CATALYSTS

    SciTech Connect

    Paul Chin; George W. Roberts; James J. Spivey

    2003-12-31

    Uses for structured catalytic supports, such as ceramic straight-channel monoliths and ceramic foams, have been established for a long time. One of the most prominent examples is the washcoated ceramic monolith as a three-way catalytic converter for gasoline-powered automobiles. A distinct alternative to the ceramic monolith is the metal foam, with potential use in fuel cell-powered automobiles. The metal foams are characterized by their pores per inch (ppi) and density ({rho}). In previous research, using 5 wt% platinum (Pt) and 0.5 wt% iron (Fe) catalysts, washcoated metal foams, 5.08 cm in length and 2.54 cm in diameter, of both varying and similar ppi and {rho} were tested for their activity (X{sub CO}) and selectivity (S{sub CO}) on a CO preferential oxidation (PROX) reaction in the presence of a H{sub 2}-rich gas stream. The variances in these metal foams' activity and selectivity were much larger than expected. Other structured supports with 5 wt% Pt, 0-1 wt% Fe weight loading were also examined. A theory for this phenomenon states that even though these structured supports have a similar nominal catalyst weight loading, only a certain percentage of the Pt/Fe catalyst is exposed on the surface as an active site for CO adsorption. We will use two techniques, pulse chemisorption and temperature programmed desorption (TPD), to characterize our structured supports. Active metal count, metal dispersion, and other calculations will help clarify the causes for the activity and selectivity variations between the supports. Results on ceramic monoliths show that a higher Fe loading yields a lower dispersion, potentially because of Fe inhibition of the Pt surface for CO adsorption. This theory is used to explain the reason for activity and selectivity differences for varying ppi and {rho} metal foams; less active and selective metal foams have a lower Fe loading, which justifies their higher metal dispersion. Data on the CO desorption temperature and average metal

  16. Effectiveness of a dopant in U-Zr metallic fuel to prevent lanthanide migration

    SciTech Connect

    Kim, Yeon Soo; Wieneck, T.; O'Hare, E.; Fortner, J.

    2013-07-01

    The advanced fast reactor concepts to achieve ultra-high burnup (about 50%) without requiring refueling by way of using metallic alloy fuel have gained interest. Fission product lanthanide accumulation at high burnup is substantial and its migration to cladding and reaction with cladding is a potential life-limiting phenomenon. As a means to solve this problem, adding an element that forms stable compounds with lanthanides to immobilize them has been proposed. The theoretical assessment shows that indium, thallium, gallium, and antimony are good candidates. Except for Sb, because these elements are low-melting temperature elements, liquid metal embrittlement of cladding is a concern if large sized agglomerates exist contacting the cladding. Alloy characterization of as-fabricated samples was performed to examine the effectiveness of the dopant addition method using optical microscopy and scanning electron microscopy. Although preliminary, the present results showed that indium is a better dopant to immobilize lanthanides.

  17. Method of improving fuel cell performance by removing at least one metal oxide contaminant from a fuel cell electrode

    DOEpatents

    Kim, Yu Seung; Choi, Jong-Ho; Zelenay, Piotr

    2009-08-18

    A method of removing contaminants from a fuel cell catalyst electrode. The method includes providing a getter electrode and a fuel cell catalyst electrode having at least one contaminant to a bath and applying a voltage sufficient to drive the contaminant from the fuel cell catalyst electrode to the getter electrode. Methods of removing contaminants from a membrane electrode assembly of a fuel cell and of improving performance of a fuel cell are also provided.

  18. Emission of Metals from Pelletized and Uncompressed Biomass Fuels Combustion in Rural Household Stoves in China

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Tong, Yindong; Wang, Huanhuan; Chen, Long; Ou, Langbo; Wang, Xuejun; Liu, Guohua; Zhu, Yan

    2014-07-01

    Effort of reducing CO2 emissions in developing countries may require an increasing utilization of biomass fuels. Biomass pellets seem well-suited for residential biomass markets. However, there is limited quantitative information on pollutant emissions from biomass pellets burning, especially those measured in real applications. In this study, biomass pellets and raw biomass fuels were burned in a pellet burner and a conventional stove respectively, in rural households, and metal emissions were determined. Results showed that the emission factors (EFs) ranged 3.20-5.57 (Pb), 5.20-7.58 (Cu), 0.11-0.23 (Cd), 12.67-39.00 (As), 0.59-1.31 mg/kg (Ni) for pellets, and 0.73-1.34 (Pb), 0.92-4.48 (Cu), 0.08-0.14 (Cd), 7.29-13.22 (As), 0.28-0.62 (Ni) mg/kg for raw biomass. For unit energy delivered to cooking vessels, the EFs ranged 0.42-0.77 (Pb), 0.79-1.16 (Cu), 0.01-0.03 (Cd), 1.93-5.09 (As), 0.08-0.19 mg/MJ (Ni) for pellets, and 0.30-0.56 (Pb), 0.41-1.86 (Cu), 0.04-0.06 (Cd), 3.25-5.49 (As), 0.12-0.26 (Ni) mg/MJ for raw biomass. This study found that moisture, volatile matter and modified combustion efficiency were the important factors affecting metal emissions. Comparisons of the mass-based and task-based EFs found that biomass pellets produced higher metal emissions than the same amount of raw biomass. However, metal emissions from pellets were not higher in terms of unit energy delivered.

  19. Accumulation of fossil fuels and metallic minerals in active and ancient rift lakes

    USGS Publications Warehouse

    Robbins, E.I.

    1983-01-01

    A study of active and ancient rift systems around the world suggests that accumulations of fossil fuels and metallic minerals are related to the interactions of processes that form rift valleys with those that take place in and around rift lakes. The deposition of the precursors of petroleum, gas, oil shale, coal, phosphate, barite, Cu-Pb-Zn sulfides, and uranium begins with erosion of uplifted areas, and the consequent input of abundant nutrients and solute loads into swamps and tectonic lakes. Hot springs and volcanism add other nutrients and solutes. The resulting high biological productivity creates oxidized/reduced interfaces, and anoxic and H2S-rich bottom waters which preserves metal-bearing organic tissues and horizons. In the depositional phases, the fine-grained lake deposits are in contact with coarse-grained beach, delta, river, talus, and alluvial fan deposits. Earthquake-induced turbidites also are common coarse-grained deposits of rift lakes. Postdepositional processes in rifts include high heat flow and a resulting concentration of the organic and metallic components that were dispersed throughout the lakebeds. Postdepositional faulting brings organic- and metal-rich sourcebeds in contact with coarse-grained host and reservoir rocks. A suite of potentially economic deposits is therefore a characteristic of rift valleys. ?? 1983.

  20. Manufacturing and characterization of metal-supported solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Blennow, Peter; Hjelm, Johan; Klemensø, Trine; Ramousse, Severine; Kromp, Alexander; Leonide, André; Weber, André

    A metal-supported solid oxide fuel cell design offers competitive advantages, for example reduced material costs and improved robustness. This paper reports the performance and stability of a recently developed metal-supported cell design, based on a novel cermet anode, on a 25 cm 2 (1 cm 2/16 cm 2 active area) cell level. An electrochemical performance comparable to state-of-the-art anode-supported cells is demonstrated. Detailed electrochemical analysis allowed assignment of the overall polarization losses quantitatively to gas diffusion in the metal support, electrooxidation in the anode functional layer, oxygen reduction in the mixed ionic-electronic conducting cathode and an additional polarization process with a rather high relaxation frequency, which may be assigned to an insulating corrosion interlayer. The durability of the cells was investigated by means of galvanostatic operation for periods of up to 1000 h as well as the dynamic behavior, such as redox-, load- and thermal cycling tests. The galvanostatic stability tests indicated a fair, but significant degradation rate (∼5% decrease in cell voltage/1000 h at 650 °C and 0.25 A cm -2). Furthermore, the metal-supported cells underwent an endurance test of 100 redox cycles at 800 °C without severe degradation nor total failure.

  1. Do trace metals (chromium, copper, and nickel) influence toxicity of diesel fuel for free-living marine nematodes?

    PubMed

    Hedfi, Amor; Boufahja, Fehmi; Ben Ali, Manel; Aïssa, Patricia; Mahmoudi, Ezzeddine; Beyrem, Hamouda

    2013-06-01

    The objective of this study was to test the hypotheses that (1) free-living marine nematodes respond in a differential way to diesel fuel if it is combined with three trace metals (chromium, copper, and nickel) used as smoke suppressants and that (2) the magnitude of toxicity of diesel fuel differs according to the level of trace metal mixture added. Nematodes from Sidi Salem beach (Tunisia) were subjected separately for 30 days to three doses of diesel fuel and three others of a trace metals mixture. Simultaneously, low-dose diesel was combined with three amounts of a trace metal mixture. Results from univariate and multivariate methods of data evaluation generally support our initial hypothesis that nematode assemblages exhibit various characteristic changes when exposed to different types of disturbances; the low dose of diesel fuel, discernibly non-toxic alone, became toxic when trace metals were added. For all types of treatments, biological disturbance caused severe specific changes in assemblage structure. For diesel fuel-treated microcosms, Marylynnia bellula and Chromaspirinia pontica were the best positive indicative species; their remarkable presence in given ecosystem may predict unsafe seafood. The powerful toxicity of the combination between diesel fuel and trace metals was expressed with only negative bioindicators, namely Trichotheristus mirabilis, Pomponema multipapillatum, Ditlevsenella murmanica, Desmodora longiseta, and Bathylaimus capacosus. Assemblages with high abundances of these species should be an index of healthy seafood. When nematodes were exposed to only trace metals, their response looks special with a distinction of a different list of indicative species; the high presence of seven species (T. mirabilis, P. multipapillatum, Leptonemella aphanothecae, D. murmanica, Viscosia cobbi, Gammanema conicauda, and Viscosia glabra) could indicate a good quality of seafood and that of another species (Oncholaimellus mediterraneus) appeared an

  2. Irradiation performance of nitride fuels

    SciTech Connect

    Matthews, R.B.

    1993-01-01

    The properties and advantages of nitride fuels are well documented in the literature. Basically the high thermal conductivity and uranium density of nitride fuels permit high power density, good breeding ratios, low reactivity swings, and large diameter pins compared to oxides. Nitrides are compatible with cladding alloys and liquid metal coolants, thereby reducing fuel/cladding chemical interactions and permitting the use of sodium-bonded pins and the operation of breached pins. Recent analyses done under similar operating conditions show that - compared to metal - fuels mixed nitrides operate at lower temperatures, produce less cladding strain, have greater margins to failure, result in lower transient temperatures, and have lower sodium void reactivity. Uranium nitride fuel pellet fabrication processes were demonstrated during the SP-100 program, and irradiated nitride fuels can be reprocessed by the PUREX process. Irradiation performance data suggest that nitrides have low fission gas release and swelling rates thereby permitting favorable pin designs and long lifetime. The objective of this report is to summarize the available nitride irradiation performance data base and to recommend optimum nitride characteristics for use in advanced liquid metal reactors.

  3. Investigation on heavy liquid metal cooling of ADS fuel pin assemblies

    NASA Astrophysics Data System (ADS)

    Litfin, K.; Batta, A.; Class, A. G.; Wetzel, Th.; Stieglitz, R.

    2011-08-01

    In the framework of accelerator driven sub-critical reactor systems heavy liquid metals are considered as coolant for the reactor core and the spallation target. In particular lead or lead bismuth eutectic (LBE) exhibit efficient heat removal properties and high production rate of neutrons. However, the excellent heat conductivity of LBE-flows expressed by a low molecular Prandtl number of the order 10 -2 requires improved modeling of the turbulent heat transfer. Although various models for thermal hydraulics of LBE flows are existing, validated heat transfer correlations for ADS-relevant conditions are still missing. In order to validate the sub-channel codes and computational fluid dynamics codes used to design fuel assemblies, the comparison with experimental data is inevitable. Therefore, an experimental program composed of three major experiments, a single electrically heated rod, a 19-pin hexagonal water rod bundle and a LBE rod bundle, has been initiated at the Karlsruhe Liquid metal Laboratory (KALLA) of the Karlsruhe Institute of Technology, in order to quantify and separate the individual phenomena occurring in the momentum and energy transfer of a fuel assembly.

  4. Impact of Fuel Metal Impurities on the Durability of a Light-Duty Diesel Aftertreatment System

    SciTech Connect

    Williams, A.; Burton, J.; McCormick, R. L.; Toops, T.; Wereszczak, A. A.; Fox, E. E.; Lance, M. J.; Cavataio, G.; Dobson, D.; Warner, J.; Brezny, R.; Nguyen, K.; Brookshear, D. W.

    2013-04-01

    Alkali and alkaline earth metal impurities found in diesel fuels are potential poisons for diesel exhaust catalysts. A set of diesel engine production exhaust systems was aged to 150,000 miles. These exhaust systems included a diesel oxidation catalyst, selective catalytic reduction (SCR) catalyst, and diesel particulate filter (DPF). Four separate exhaust systems were aged, each with a different fuel: ultralow sulfur diesel containing no measureable metals, B20 (a common biodiesel blend) containing sodium, B20 containing potassium, and B20 containing calcium, which were selected to simulate the maximum allowable levels in B100 according to ASTM D6751. Analysis included Federal Test Procedure emissions testing, bench-flow reactor testing of catalyst cores, electron probe microanalysis (EPMA), and measurement of thermo-mechanical properties of the DPFs. EPMA imaging found that the sodium and potassium penetrated into the washcoat, while calcium remained on the surface. Bench-flow reactor experiments were used to measure the standard nitrogen oxide (NOx) conversion, ammonia storage, and ammonia oxidation for each of the aged SCR catalysts. Vehicle emissions tests were conducted with each of the aged catalyst systems using a chassis dynamometer. The vehicle successfully passed the 0.2 gram/mile NOx emission standard with each of the four aged exhaust systems.

  5. Dust survey following the final shutdown of TEXTOR: metal particles and fuel retention

    NASA Astrophysics Data System (ADS)

    Fortuna-Zaleśna, E.; Weckmann, A.; Grzonka, J.; Rubel, M.; Esser, H. G.; Freisinger, M.; Kreter, A.; Sergienko, G.; Ström, P.

    2016-02-01

    The work presents results of a broad TEXTOR dust survey in terms of its composition, structure, distribution and fuel content. The dust particles were collected after final shutdown of TEXTOR in December 2013. Fuel retention, as determined by thermal desorption, varied significantly, even by two orders of magnitude, dependent on the dust location in the machine. Dust structure was examined by means of scanning electron microscopy combined with energy-dispersive x-ray spectroscopy, focused ion beam and scanning transmission electron microscopy. Several categories of dust have been identified. Carbon-based stratified and granular deposits were dominating, but the emphasis in studies was on metal dust. They were found in the form of small particles, small spheres, flakes and splashes which formed ‘comet’-like structures, clearly indicating directional effects in the impact on surfaces of plasma-facing components. Nickel-rich alloys from the Inconel liner and iron-based ones from various diagnostic holders were the main components of metal-containing dust, but also molybdenum and tungsten debris were detected. Their origin is discussed.

  6. Scrotal Swelling in the Neonate

    PubMed Central

    Basta, Amaya M.; Courtier, Jesse; Phelps, Andrew; Copp, Hillary L.; MacKenzie, John D.

    2016-01-01

    Discovery of scrotal swelling in a neonate can be a source of anxiety for parents, clinicians, and sonologists alike. This pictorial essay provides a focused review of commonly encountered scrotal masses and mimics specific to the neonatal setting. Although malignancy is a concern, it is very uncommon, as most neonatal scrotal masses are benign. Key discriminating features and management options are highlighted to improve the radiologist’s ability to diagnose neonatal scrotal conditions and guide treatment decisions. Neonatal scrotal processes ranging from common to uncommon will be discussed. PMID:25715370

  7. Development of novel proton exchange membrane fuel cells using stamped metallic bipolar plates

    NASA Astrophysics Data System (ADS)

    Jung, Shiauh-Ping; Lee, Chun-I.; Chen, Chi-Chang; Chang, Wen-Sheng; Yang, Chang-Chung

    2015-06-01

    This study presents the development of novel proton exchange membrane fuel cells using stamped metallic bipolar plates. To achieve uniformly distributed and low pressure-drop flow fields within fuel cells, a novel bipolar plate with straight channels is designed and verification of a fuel-cell short stack using this bipolar plate is performed. In the experiments, low-temperature and low-humidity operations and high-temperature and high-humidity operations are adopted to evaluate effects of stack temperature and inlet relative humidity on performance at various outlet pressures. Experimental results show that under low-temperature and low-humidity operations, increasing the outlet pressure enhances stack performance and reduces performance differences between various stack temperatures. Under high-temperature and high-humidity operations, stack performance increases with increasing outlet pressures, while the extent of their increase becomes smaller. Compared to low-temperature and low-humidity operations, high-temperature and high-humidity operations have better electrochemical reactions and membrane hydration and, thus, better stack performance. In this study, the operation with a stack temperature of 80 °C and outlet pressure of 4 atm produces the best performance of 1100 mA cm-2 at 0.646 V.

  8. Preliminary Compatibility Assessment of Metallic Dispenser Materials for Service in Ethanol Fuel Blends

    SciTech Connect

    Pawel, Steven J; Kass, Michael D; Janke, Christopher James

    2009-11-01

    The compatibility of selected metals representative of those commonly used in dispensing systems was evaluated in an aggressive E20 formulation (CE20a) and in synthetic gasoline (Reference Fuel C) in identical testing to facilitate comparison of results. The testing was performed at modestly elevated temperature (nominally 60 C) and with constant fluid flow in an effort to accelerate potential interactions in the screening test. Based on weight change, the general corrosion of all individual coupons exposed in the vapor phase above Reference Fuel C and CE20a as well as all coupons immersed in Reference Fuel C was essentially nil (<0.3 {micro}m/y), with no evidence of localized corrosion such as pitting/crevice corrosion or selective leaching at any location. Modest discoloration was observed on the copper-based alloys (cartridge brass and phosphor bronze), but the associated corrosion films were quite thin and apparently protective. For coupons immersed in CE20a, four different materials exhibited net weight loss over the entire course of the experiment: cartridge brass, phosphor bronze, galvanized steel, and terne-plated steel. None of these exhibited substantial incompatibility with the test fluid, with the largest general corrosion rate calculated from coupon weight loss to be approximately 4 {micro}m/y for the cartridge brass specimens. Selective leaching of zinc (from brass) and tin (from bronze) was observed, as well as the presence of sulfide surface films rich in these elements, suggesting the importance of the role of sulfuric acid in the CE20a formulation. Analysis of weight loss data for the slightly corroded metals indicated that the corrosivity of the test environment decreased with exposure time for brass and bronze and increased for galvanized and terne-plated steel. Other materials immersed in CE20a - type 1020 mild steel, type 1100 aluminum, type 201 nickel, and type 304 stainless steel - each appeared essentially immune to corrosion at the test

  9. Microbial fuel cell driving electrokinetic remediation of toxic metal contaminated soils.

    PubMed

    Habibul, Nuzahat; Hu, Yi; Sheng, Guo-Ping

    2016-11-15

    An investigation of the feasibility of in-situ electrokinetic remediation for toxic metal contaminated soil driven by microbial fuel cell (MFC) is presented. Results revealed that the weak electricity generated from MFC could power the electrokinetic remediation effectively. The metal removal efficiency and its influence on soil physiological properties were also investigated. With the electricity generated through the oxidation of organics in soils by microorganisms, the metals in the soils would mitigate from the anode to the cathode. The concentrations of Cd and Pb in the soils increased gradually through the anode to the cathode regions after remediation. After about 143days and 108 days' operation, the removal efficiencies of 31.0% and 44.1% for Cd and Pb at the anode region could be achieved, respectively. Soil properties such as pH and soil conductivity were also significantly redistributed from the anode to the cathode regions. The study shows that the MFC driving electrokinetic remediation technology is cost-effective and environmental friendly, with a promising application in soil remediation. PMID:27388419

  10. Effect of delivery condition on desorption rate of ZrCo metal hydride bed for fusion fuel cycle

    SciTech Connect

    Kang, H.G.; Yun, S.H.; Chung, D.; Oh, Y.H.; Chang, M.H.; Cho, S.; Chung, H.; Song, K.M.

    2015-03-15

    For the safety of fusion fuel cycle, hydrogen isotope gases including tritium are stored as metal hydride form. To satisfy fueling requirement of fusion machine, rapid delivery from metal hydride bed is one of major factors for the development of tritium storage and delivery system. Desorption from metal hydride depends on the operation scenario by pressure and temperature control of the bed. The effect of operation scenario and pump performance on desorption rate of metal hydride bed was experimentally investigated using ZrCo bed. The results showed that the condition of pre-heating scenario before actual delivery of gas affected the delivery performance. Different pumps were connected to desorption line from bed and the effect of pump capacity on desorption rate were also found to be significant. (authors)

  11. Novel architectured metal-supported solid oxide fuel cells with Mo-doped SrFeO3-δ electrocatalysts

    NASA Astrophysics Data System (ADS)

    Zhou, Yucun; Meng, Xie; Liu, Xuejiao; Pan, Xin; Li, Junliang; Ye, Xiaofeng; Nie, Huaiwen; Xia, Changrong; Wang, Shaorong; Zhan, Zhongliang

    2014-12-01

    Barriers to technological advancement of metal-supported SOFCs include nickel coarsening in the anode, metallic interdiffusion between the anode and the metal substrate, as well as poor cathode adhesion. Here we report a robust and novel architectured metal-supported SOFC that consists of a thin dense yttria-stabilized zirconia (YSZ) electrolyte layer sandwiched between a porous 430L stainless steel substrate and a porous YSZ thin layer. The key feature is simultaneous use of impregnated nano-scale SrFe0.75Mo0.25O3-δ coatings on the internal surfaces of the porous 430L and YSZ backbones respectively as the anode and cathode catalyst. Such a fuel cell exhibits power densities of 0.74 W cm-2 at 800 °C and 0.40 W cm-2 at 700 °C when operating on hydrogen fuels and air oxidants.

  12. CSER 94-014: Storage of metal-fuel loaded EBR-II casks in concrete vault on PFP grounds

    SciTech Connect

    Hess, A.L.

    1994-12-05

    A criticality safety evaluation is presented to permit EBR-2 spent fuel casks loaded with metallic fuel rods to be stored in an 8-ft diameter, cylindrical concrete vault inside the PFP security perimeter. The specific transfer of three casks with Pu alloy fuel from the Los Alamos Molten Plutonium Reactor Experiment from the burial grounds to the vault is thus covered. Up to seven casks may be emplaced in the casing with 30 inches center to center spacing. Criticality safety is assured by definitive packaging rules which keep the fissile medium dry and at a low effective volumetric density.

  13. Evaluation of an EMITEC resistively heated metal monolith catalytic converter on two M100 neat methanol-fueled vehicles

    NASA Astrophysics Data System (ADS)

    Piotrowski, Gregory K.; Schaefer, Ronald M.

    1992-12-01

    The report describes the evaluation of a resistively heated catalyst system on two different methanol fueled vehicles. The EMITEC catalyst consisted of a compact resistively heated metal monolith in front of a larger conventional main converter. The EMITEC catalyst was evaluated on two neat methanol-fueled vehicles, a 1981 Volkswagen Rabbit and a 1988 Toyota Corolla. Emission testing was conducted over the Federal Test Procedure (FTP) CVS-75 test cycle. The emissions of primary interest were cold start methanol (unburned fuel), carbon monoxide, and formaldehyde.

  14. Interaction of coal-derived synthesis gas impurities with solid oxide fuel cell metallic components

    NASA Astrophysics Data System (ADS)

    Marina, Olga A.; Pederson, Larry R.; Coyle, Christopher A.; Edwards, Danny J.; Chou, Yeong-Shyung; Cramer, Carolyn N.

    Oxidation-resistant alloys find use as interconnect materials, heat exchangers, and gas supply tubing in solid oxide fuel cell (SOFC) systems, especially when operated at temperatures below ∼800 °C. If fueled with synthesis gas derived from coal or biomass, such metallic components could be exposed to impurities contained in those fuel sources. In this study, coupons of ferritic stainless steels Crofer 22 APU and SS 441, austenitic nickel-chromium superalloy Inconel 600, and an alumina-forming high nickel alloy alumel were exposed to synthesis gas containing ≤2 ppm phosphorus, arsenic and antimony, and reaction products were tested. Crofer 22 APU coupons coated with a (Mn,Co) 3O 4 protective layer were also evaluated. Phosphorus was found to be the most reactive. On Crofer 22 APU, the (Mn,Cr) 3O 4 passivation layer reacted to form an Mn-P-O product, predicted to be manganese phosphate from thermochemical calculations, and Cr 2O 3. On SS 441, reaction of phosphorus with (Mn,Cr) 3O 4 led to the formation of manganese phosphate as well as an Fe-P product, predicted from thermochemical calculations to be Fe 3P. Minimal interactions with antimony or arsenic in synthesis gas were limited to Fe-Sb and Fe-As solid solution formation. Though not intended for use on the anode side, a (Mn,Co) 3O 4 spinel coating on Crofer 22 APU reacted with phosphorus in synthesis gas to produce products consistent with Mn 3(PO 4) 2 and Co 2P. A thin Cr 2O 3 passivation layer on Inconel 600 did not prevent the formation of nickel phosphides and arsenides and of iron phosphides and arsenides, though no reaction with Cr 2O 3 was apparent. On alumel, an Al 2O 3 passivation layer rich in Ni did not prevent the formation of nickel phosphides, arsenides, and antimonides, though no reaction with Al 2O 3 occurred. This work shows that unprotected metallic components of an SOFC stack and system can provide a sink for P, As and Sb impurities that may be present in fuel gases, and thus complicate

  15. Malignant cerebral swelling following cranioplasty.

    PubMed

    Honeybul, S; Damodaran, O; Lind, C R P; Lee, G

    2016-07-01

    Over the past few years there have been a number of case reports and small cohort studies that have described so called "malignant" cerebral swelling following an uneventful cranioplasty procedure. The pathophysiology remains to be established however it has been suggested that it may be related to a combination of failure of autoregulation and the use of closed vacuum suction drainage. The current study presents three further patients who had had a decompressive hemicraniectomy for ischaemic stroke. If decompressive craniectomy is utilised in the management of neurological emergencies, close attention and wider reporting of this type of complication is required not only to focus attention on possible management strategies, but also to determine which patients are at most risk of this devastating complication. PMID:27189792

  16. Emission of Metals from Pelletized and Uncompressed Biomass Fuels Combustion in Rural Household Stoves in China

    PubMed Central

    Zhang, Wei; Tong, Yindong; Wang, Huanhuan; Chen, Long; Ou, Langbo; Wang, Xuejun; Liu, Guohua; Zhu, Yan

    2014-01-01

    Effort of reducing CO2 emissions in developing countries may require an increasing utilization of biomass fuels. Biomass pellets seem well-suited for residential biomass markets. However, there is limited quantitative information on pollutant emissions from biomass pellets burning, especially those measured in real applications. In this study, biomass pellets and raw biomass fuels were burned in a pellet burner and a conventional stove respectively, in rural households, and metal emissions were determined. Results showed that the emission factors (EFs) ranged 3.20–5.57 (Pb), 5.20–7.58 (Cu), 0.11–0.23 (Cd), 12.67–39.00 (As), 0.59–1.31 mg/kg (Ni) for pellets, and 0.73–1.34 (Pb), 0.92–4.48 (Cu), 0.08–0.14 (Cd), 7.29–13.22 (As), 0.28–0.62 (Ni) mg/kg for raw biomass. For unit energy delivered to cooking vessels, the EFs ranged 0.42–0.77 (Pb), 0.79–1.16 (Cu), 0.01–0.03 (Cd), 1.93–5.09 (As), 0.08–0.19 mg/MJ (Ni) for pellets, and 0.30–0.56 (Pb), 0.41–1.86 (Cu), 0.04–0.06 (Cd), 3.25–5.49 (As), 0.12–0.26 (Ni) mg/MJ for raw biomass. This study found that moisture, volatile matter and modified combustion efficiency were the important factors affecting metal emissions. Comparisons of the mass-based and task-based EFs found that biomass pellets produced higher metal emissions than the same amount of raw biomass. However, metal emissions from pellets were not higher in terms of unit energy delivered. PMID:25002204

  17. Ceramic plasma-sprayed coating of melting crucibles for casting metal fuel slugs

    NASA Astrophysics Data System (ADS)

    Kim, Ki Hwan; Lee, Chong Tak; Lee, Chan Bock; Fielding, R. S.; Kennedy, J. R.

    2013-10-01

    Thermal cycling and melt reaction studies of ceramic coatings plasma-sprayed on Nb substrates were carried out to evaluate the performance of barrier coatings for metallic fuel casting applications. Thermal cycling tests of the ceramic plasma-sprayed coatings to 1450 °C showed that HfN, TiC, ZrC, and Y2O3 coating had good cycling characteristics with few interconnected cracks even after 20 cycles. Interaction studies by 1550 °C melt dipping tests of the plasma-sprayed coatings also indicated that HfN and Y2O3 do not form significant reaction layer between U-20 wt.% Zr melt and the coating layer. Plasma-sprayed Y2O3 coating exhibited the most promising characteristics among HfN, TiC, ZrC, and Y2O3 coating.

  18. Metallic plate corrosion and uptake of corrosion products by nafion in polymer electrolyte membrane fuel cells.

    PubMed

    Bozzini, Benedetto; Gianoncelli, Alessandra; Kaulich, Burkhard; Kiskinova, Maya; Prasciolu, Mauro; Sgura, Ivonne

    2010-07-19

    Nafion contamination by ferrous-alloy corrosion products, resulting in dramatic drops of the Ohmic potential, is a suspected major failure mode of polymer electrolyte membrane fuel cells that make use of metallic bipolar plates. This study demonstrates the potential of scanning transmission X-ray microscopy combined with X-ray absorption and fluorescence microspectroscopy for exploring corrosion processes of Ni and Fe electrodes in contact with a hydrated Nafion film in a thin-layer cell. The imaged morphology changes of the Ni and Fe electrodes and surrounding Nafion film that result from relevant electrochemical processes are correlated to the spatial distribution, local concentration, and chemical state of Fe and Ni species. The X-ray fluorescence maps and absorption spectra, sampled at different locations, show diffusion of corrosion products within the Nafion film only in the case of the Fe electrodes, whereas the Ni electrodes appear corrosion resistant. PMID:20564283

  19. Ceramic plasma-sprayed coating of melting crucibles for casting metal fuel slugs

    SciTech Connect

    K.H. Kim; C.T. Lee; C.B. Lee; R.S. Fielding; J.R. Kennedy

    2013-10-01

    Thermal cycling and melt reaction studies of ceramic coatings plasma-sprayed on Nb substrates were carried out to evaluate the performance of barrier coatings for metallic fuel casting applications. Thermal cycling tests of the ceramic plasma-sprayed coatings to 1450 degrees C showed that HfN, TiC, ZrC, and Y2O3 coating had good cycling characteristics with few interconnected cracks even after 20 cycles. Interaction studies by 1550 degrees C melt dipping tests of the plasma-sprayed coatings also indicated that HfN and Y2O3 do not form significant reaction layer between U–20 wt.% Zr melt and the coating layer. Plasma-sprayed Y2O3 coating exhibited the most promising characteristics among HfN, TiC, ZrC, and Y2O3 coating.

  20. Prediction of swelling rocks strain in tunneling

    NASA Astrophysics Data System (ADS)

    Parsapour, D.; Fahimifar, A.

    2016-05-01

    Swelling deformations leading to convergence of tunnels may result in significant difficulties during the construction, in particular for long term use of tunnels. By extracting an experimental based explicit analytical solution for formulating swelling strains as a function of time and stress, swelling strains are predicted from the beginning of excavation and during the service life of tunnel. Results obtained from the analytical model show a proper agreement with experimental results. This closed-form solution has been implemented within a numerical program using the finite element method for predicting time-dependent swelling strain around tunnels. Evaluating effects of swelling parameters on time-dependent strains and tunnel shape on swelling behavior around the tunnel according to this analytical solution is considered. The ground-support interaction and consequent swelling effect on the induced forces in tunnel lining is considered too. Effect of delay in lining installation on swelling pressure which acting on the lining and its structural integrity, is also evaluated. A MATLAB code of " SRAP" is prepared and applied to calculate all swelling analysis around tunnels based on analytical solution.

  1. Environmentally Friendly Carbon-Preserving Recovery of Noble Metals From Supported Fuel Cell Catalysts.

    PubMed

    Latsuzbaia, R; Negro, E; Koper, G J M

    2015-06-01

    The dissolution of noble-metal catalysts under mild and carbon-preserving conditions offers the possibility of in situ regeneration of the catalyst nanoparticles in fuel cells or other applications. Here, we report on the complete dissolution of the fuel cell catalyst, platinum nanoparticles, under very mild conditions at room temperature in 0.1 M HClO4 and 0.1 M HCl by electrochemical potential cycling between 0.5-1.1 V at a scan rate of 50 mV s(-1) . Dissolution rates as high as 22.5 μg cm(-2) per cycle were achieved, which ensured a relatively short dissolution timescale of 3-5 h for a Pt loading of 0.35 mg cm(-2) on carbon. The influence of chloride ions and oxygen in the electrolyte on the dissolution was investigated, and a dissolution mechanism is proposed on the basis of the experimental observations and available literature results. During the dissolution process, the corrosion of the carbon support was minimal, as observed by X-ray photoelectron spectroscopy (XPS).

  2. Highly stable precious metal-free cathode catalyst for fuel cell application

    NASA Astrophysics Data System (ADS)

    Serov, Alexey; Workman, Michael J.; Artyushkova, Kateryna; Atanassov, Plamen; McCool, Geoffrey; McKinney, Sam; Romero, Henry; Halevi, Barr; Stephenson, Thomas

    2016-09-01

    A platinum group metal-free (PGM-free) oxygen reduction reaction (ORR) catalyst engineered for stability has been synthesized using the sacrificial support method (SSM). This catalyst was comprehensively characterized by physiochemical analyses and tested for performance and durability in fuel cell membrane electrode assemblies (MEAs). This catalyst, belonging to the family of Fe-N-C materials, is easily scalable and can be manufactured in batches up to 200 g. The fuel cell durability tests were performed in a single cell configuration at realistic operating conditions of 0.65 V, 1.25 atmgauge air, and 90% RH for 100 h. In-depth characterization of surface chemistry and morphology of the catalyst layer before and after durability tests were performed. The failure modes of the PGM-free electrodes were derived from structure-to-property correlations. It is suggested that under constant voltage operation, the performance loss results from degradation of the electrode pore structure, while under carbon corrosion accelerated test protocols the failure mode is catalyst corrosion.

  3. Environmentally Friendly Carbon-Preserving Recovery of Noble Metals From Supported Fuel Cell Catalysts.

    PubMed

    Latsuzbaia, R; Negro, E; Koper, G J M

    2015-06-01

    The dissolution of noble-metal catalysts under mild and carbon-preserving conditions offers the possibility of in situ regeneration of the catalyst nanoparticles in fuel cells or other applications. Here, we report on the complete dissolution of the fuel cell catalyst, platinum nanoparticles, under very mild conditions at room temperature in 0.1 M HClO4 and 0.1 M HCl by electrochemical potential cycling between 0.5-1.1 V at a scan rate of 50 mV s(-1) . Dissolution rates as high as 22.5 μg cm(-2) per cycle were achieved, which ensured a relatively short dissolution timescale of 3-5 h for a Pt loading of 0.35 mg cm(-2) on carbon. The influence of chloride ions and oxygen in the electrolyte on the dissolution was investigated, and a dissolution mechanism is proposed on the basis of the experimental observations and available literature results. During the dissolution process, the corrosion of the carbon support was minimal, as observed by X-ray photoelectron spectroscopy (XPS). PMID:25959077

  4. An anisotropic numerical model for thermal hydraulic analyses: application to liquid metal flow in fuel assemblies

    NASA Astrophysics Data System (ADS)

    Vitillo, F.; Vitale Di Maio, D.; Galati, C.; Caruso, G.

    2015-11-01

    A CFD analysis has been carried out to study the thermal-hydraulic behavior of liquid metal coolant in a fuel assembly of triangular lattice. In order to obtain fast and accurate results, the isotropic two-equation RANS approach is often used in nuclear engineering applications. A different approach is provided by Non-Linear Eddy Viscosity Models (NLEVM), which try to take into account anisotropic effects by a nonlinear formulation of the Reynolds stress tensor. This approach is very promising, as it results in a very good numerical behavior and in a potentially better fluid flow description than classical isotropic models. An Anisotropic Shear Stress Transport (ASST) model, implemented into a commercial software, has been applied in previous studies, showing very trustful results for a large variety of flows and applications. In the paper, the ASST model has been used to perform an analysis of the fluid flow inside the fuel assembly of the ALFRED lead cooled fast reactor. Then, a comparison between the results of wall-resolved conjugated heat transfer computations and the results of a decoupled analysis using a suitable thermal wall-function previously implemented into the solver has been performed and presented.

  5. The thermodynamics of pyrochemical processes for liquid metal reactor fuel cycles

    SciTech Connect

    Johnson, I.

    1987-01-01

    The thermodynamic basis for pyrochemical processes for the recovery and purification of fuel for the liquid metal reactor fuel cycle is described. These processes involve the transport of the uranium and plutonium from one liquid alloy to another through a molten salt. The processes discussed use liquid alloys of cadmium, zinc, and magnesium and molten chloride salts. The oxidation-reduction steps are done either chemically by the use of an auxiliary redox couple or electrochemically by the use of an external electrical supply. The same basic thermodynamics apply to both the salt transport and the electrotransport processes. Large deviations from ideal solution behavior of the actinides and lanthanides in the liquid alloys have a major influence on the solubilities and the performance of both the salt transport and electrotransport processes. Separation of plutonium and uranium from each other and decontamination from the more noble fission product elements can be achieved using both transport processes. The thermodynamic analysis is used to make process design computations for different process conditions.

  6. Phase Characteristics of a Number of U-Pu-Am-Np-Zr Metallic Alloys for Use as Fast Reactor Fuels

    SciTech Connect

    Douglas E. Burkes; J. Rory Kennedy; Thomas Hartmann; Cynthia A. Papesch; Denis D. Keiser, Jr.

    2010-01-01

    Metallic fuel alloys consisting of uranium, plutonium, and zirconium with minor additions of americium and neptunium are under evaluation for potential use to transmute long-lived transuranic actinide isotopes in fast reactors. A series of test designs for the Advanced Fuel Cycle Initiative (AFCI) have been irradiated in the Advanced Test Reactor (ATR), designated as the AFC-1 and AFC-2 designs. Metal fuel compositions in these designs have included varying amounts of U, Pu, Zr, and minor actinides (Am, Np). Investigations into the phase behavior and relationships based on the alloy constituents have been conducted using x-ray diffraction and differential thermal analysis. Results of these investigations, along with proposed relationships between observed behavior and alloy composition, are provided. In general, observed behaviors can be predicted by a ternary U-Pu-Zr phase diagram, with transition temperatures being most dependent on U content. Furthermore, the enthalpy associated with transitions is strongly dependent on the as-cast microstructural characteristics.

  7. One pot electrochemical synthesis of polymer/CNT/metal nanoparticles for fuel cell applications

    NASA Astrophysics Data System (ADS)

    Ventrapragada, Lakshman; Zhu, Jingyi; Karakaya, Mehmet; Podila, Ramakrishna; Rao, Apparao; Clemson Nanomaterials center Team

    Carbon nanotubes (CNTs) have become a key player in the design of materials for energy applications. They gained their popularity in industrial and scientific research due to their unique properties like excellent conductivity, high surface area, etc. Here we used chemical vapor deposition (CVD) to synthesize two types of CNTs namely, helically coiled CNTs and vertically aligned CNTs. These CNTs were subsequently used to make composites with conducting polymers and metal nanoparticles. One pot electrochemical synthesis was designed to electropolymerize aniline, pyrrole etc. on the surface of the electrode with simultaneous deposition of platinum and gold metal nanoparticles, and CNTs in the polymer matrix. The as synthesized composite materials were characterized with scanning electron microscope for surface morphology and spectroscopic techniques like Raman, UV-Vis for functionality. These were used to study electrocatalytic oxidation of methanol and ethanol for alkaline fuel cell applications. Electrodes fabricated from these composites not only showed good kinetics but also exhibited excellent stability. Uniqueness of this composite lies in its simple two step synthesis and it doesn't involve any surfactants unlike conventional chemical synthesis routes.

  8. A novel Ni/ceria-based anode for metal-supported solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Rojek-Wöckner, Veronika A.; Opitz, Alexander K.; Brandner, Marco; Mathé, Jörg; Bram, Martin

    2016-10-01

    For optimization of ageing behavior, electrochemical performance, and sulfur tolerance of metal-supported solid oxide fuel cells a new anode concept is introduced, which is based on a Ni/GDC cermet replacing the established Ni/YSZ anodes. In the present work optimized processing parameters compatible with MSC substrates are specified by doing sintering studies on pressed bulk specimen and on real porous anode structures. The electrochemical performance of the Ni/GDC anodes was characterized by means of symmetrical electrolyte supported model-type cells. In this study, three main objectives are pursued. Firstly, the effective technical realization of the Ni/GDC concept is demonstrated. Secondly, the electrochemical behavior of Ni/GDC porous anodes is characterized by impedance spectroscopy and compared with the current standard Ni/YSZ anode. Further, a qualitative comparison of the sulfur poisoning behavior of both anode types is presented. Thirdly, preliminary results of a successful implementation of the Ni/GDC cermet into a metal-supported single cell are presented.

  9. Metal-organic frameworks for removal of Xe and Kr from nuclear fuel reprocessing plants.

    PubMed

    Liu, Jian; Thallapally, Praveen K; Strachan, Denis

    2012-08-01

    Removal of xenon (Xe) and krypton (Kr) from process off-gases containing 400 ppm Xe, 40 ppm Kr, 78% N(2), 21% O(2), 0.9% Ar, 0.03% CO(2), and so forth using adsorption was demonstrated for the first time. Two well-known metal-organic frameworks (MOFs), HKUST-1 and Ni/DOBDC, which both have unsaturated metal centers but different pore morphologies, were selected as novel adsorbents. Results of an activated carbon were also included for comparison. The Ni/DOBDC has higher Xe/Kr selectivities than those of the activated carbon and the HKUST-1. In addition, results show that the Ni/DOBDC and HKUST-1 can adsorb substantial amounts of Xe and Kr even when they are mixed in air. Moreover, the Ni/DOBDC can successfully separate 400 ppm Xe from 40 ppm Kr and air containing O(2), N(2), and CO(2) with a Xe/Ke selectivity of 7.3 as indicated by our breakthrough results. This shows a promising future for MOFs in radioactive nuclide separations from spent fuels.

  10. Effect of central metal ions of analogous metal-organic frameworks on the adsorptive removal of benzothiophene from a model fuel.

    PubMed

    Khan, Nazmul Abedin; Jhung, Sung Hwa

    2013-09-15

    Liquid phase adsorption of benzothiophene (BT) has been studied over CuCl₂-loaded analogous metal-organic frameworks (MOFs), metal-benzenedicarboxylates (Me-BDCs, Me: Al, Cr and V), to understand the effect of central metal ions on the adsorptive removal of BT from a model fuel. Among the central metal ions (Al(3+), Cr(3+) and V(3+)) of the Me-BDCs only V(3+) was oxidized by the loaded CuCl₂ (or Cu(2+)) at ambient condition resulting in V(4+) and Cu(+) species. Different from the CuCl₂-loaded Al- and Cr-BDCs, the CuCl₂/V-BDC adsorbed BT remarkably well compared to the virgin V-BDCs which suggests a specific favorable interaction (π-complexation) between the obtained Cu(+) in the CuCl₂/V-BDC and BT. PMID:23892314

  11. Effect of central metal ions of analogous metal-organic frameworks on the adsorptive removal of benzothiophene from a model fuel.

    PubMed

    Khan, Nazmul Abedin; Jhung, Sung Hwa

    2013-09-15

    Liquid phase adsorption of benzothiophene (BT) has been studied over CuCl₂-loaded analogous metal-organic frameworks (MOFs), metal-benzenedicarboxylates (Me-BDCs, Me: Al, Cr and V), to understand the effect of central metal ions on the adsorptive removal of BT from a model fuel. Among the central metal ions (Al(3+), Cr(3+) and V(3+)) of the Me-BDCs only V(3+) was oxidized by the loaded CuCl₂ (or Cu(2+)) at ambient condition resulting in V(4+) and Cu(+) species. Different from the CuCl₂-loaded Al- and Cr-BDCs, the CuCl₂/V-BDC adsorbed BT remarkably well compared to the virgin V-BDCs which suggests a specific favorable interaction (π-complexation) between the obtained Cu(+) in the CuCl₂/V-BDC and BT.

  12. Compatibility between strontium-doped ferrite cathode and metallic interconnects in solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Miguel-Pérez, Verónica; Martínez-Amesti, Ana; Arriortua, María Isabel

    2015-04-01

    One of the most important issues related to the performance of solid oxide fuel cells (SOFCs) is the chromium poisoning of the perovskite-type materials used as cathodes by the gaseous chromium species from metallic interconnects. In this study, powder mixtures of LSF40-Cr2O3 were heated at 800 °C and 1000 °C in air and were subsequently analysed by X-ray powder diffraction. For all the mixtures, the crystallisation of SrCrO4 was observed. In addition, the degradation occurring between three alloys with different compositions, Crofer 22 APU, SS430 and Conicro 4023 W 188, as metallic interconnects and La0.6Sr0.4FeO3 (LSF40) ceramic material as a cathode was studied. The results show significant chromium deposition and the formation of SrCrO4, LaCrO3 and La2O3 that block the active LSF40 electrode surface and degrade the stack (YSZ/SDC/LSF40/Interconnect) performance. LSF40 assembled with SS430 exhibited substantial Cr deposition. The deposition of the Cr species and the reaction with the LSF40 cathode is related to the composition of the oxide scales formed at each metallic interconnect and at the same time is related to the composition of the alloys. The best results obtained were for the half-cell (YSZ/SDC/LSF40) in contact with Conicro 4023 W 188 and Crofer 22 APU after heat treatment in air at 800 °C for 100 h.

  13. A separate effect study of the influence of metallic fission products on CsI radioactive release from nuclear fuel

    NASA Astrophysics Data System (ADS)

    Di Lemma, F. G.; Colle, J. Y.; Beneš, O.; Konings, R. J. M.

    2015-10-01

    The chemistry of cesium and iodine is of main importance to quantify the radioactive release in case of a nuclear reactor accident, or sabotage involving irradiated nuclear materials. We studied the interaction of CsI with different metallic fission products such as Mo and Ru. These elements can be released from nuclear fuel when exposed to oxidising conditions, as in the case of contact of overheated nuclear fuel with air (e.g. in a spent fuel cask sabotage, uncovering of a spent fuel pond, or air ingress accidents). Experiments were performed by vaporizing mixtures of the compounds in air, and analysing the produced aerosols in view of a possible gas-gas and gas-aerosol reactions between the compounds. These results were compared with the gaseous species predicted by thermochemical equilibrium calculations and experimental equilibrium vaporization tests using Knudsen Effusion Mass Spectrometry.

  14. Report on Development of Concepts for the Advanced Casting System in Support of the Deployment of a Remotely Operable Research Scale Fuel Fabrication Facility for Metal Fuel

    SciTech Connect

    Ken Marsden

    2007-03-01

    Demonstration of recycle processes with low transuranic losses is key to the successful implementation of the Global Nuclear Energy Partnership strategy to manage spent fuel. It is probable that these recycle processes will include remote fuel fabrication. This report outlines the strategy to develop and implement a remote metal fuel casting process with minimal transuranic losses. The approach includes a bench-scale casting system to develop materials, methods, and perform tests with transuranics, and an engineering-scale casting system to demonstrate scalability and remote operability. These systems will be built as flexible test beds allowing exploration of multiple fuel casting approaches. The final component of the remote fuel fabrication demonstration culminates in the installation of an advanced casting system in a hot cell to provide integrated remote operation experience with low transuranic loss. Design efforts and technology planning have begun for the bench-scale casting system, and this will become operational in fiscal year 2008, assuming appropriate funding. Installation of the engineering-scale system will follow in late fiscal year 2008, and utilize materials and process knowledge gained in the bench-scale system. Assuming appropriate funding, the advanced casting system will be installed in a remote hot cell at the end of fiscal year 2009.

  15. Dynamic evaluation of low-temperature metal-supported solid oxide fuel cell oriented to auxiliary power units

    NASA Astrophysics Data System (ADS)

    Wang, Zhenwei; Berghaus, Jörg Oberste; Yick, Sing; Decès-Petit, Cyrille; Qu, Wei; Hui, Rob; Maric, Radenka; Ghosh, Dave

    A metal-supported solid oxide fuel cell (SOFC) composed of a Ni-Ce 0.8Sm 0.2O 2- δ (Ni-SDC) cermet anode and an SDC electrolyte was fabricated by suspension plasma spraying on a Hastelloy X substrate. The cathode, an Sm 0.5Sr 0.5CoO 3 (SSCo)-SDC composite, was screen-printed and fired in situ. The dynamic behaviour of the cell was measured while subjected to complete fuel shutoff and rapid start-up cycles, as typically encountered in auxiliary power units (APU) applications. A promising performance - with a maximum power density (MPD) of 0.176 W cm -2 at 600 °C - was achieved using humidified hydrogen as fuel and air as the oxidant. The cell also showed excellent resistance to oxidation at 600 °C during fuel shutoff, with only a slight drop in performance after reintroduction of the fuel. The Cr and Mn species in the Hastelloy X alloy appeared to be preferentially oxidized while the oxidation of nickel in the metallic substrate was temporarily alleviated. In rapid start-up cycles with a heating rate of 60 °C min -1, noticeable performance deterioration took place in the first two thermal cycles, and then continued at a much slower rate in subsequent cycles. A postmortem analysis of the cell suggested that the degradation was mainly due to the mismatch of the thermal expansion coefficient across the cathode/electrolyte interface.

  16. Influence of a doping by Al stainless steel on kinetics and character of interaction with the metallic nuclear fuel

    NASA Astrophysics Data System (ADS)

    Nikitin, S. N.; Shornikov, D. P.; Tarasov, B. A.; Baranov, V. G.

    2016-04-01

    Metallic nuclear fuel is a perspective kind of fuel for fast reactors. In this paper we conducted a study of the interaction between uranium-molybdenum alloy and ferritic- martensitic steels with additions of aluminum at a temperature of 700 ° C for 25 hours. The rate constants of the interaction layer growth at 700 °C is about 2.8.10-14 m2/s. It is established that doping Al stainless steel leads to decrease in interaction with uranium-molybdenum alloys. The phase composition of the interaction layer is determined.

  17. SrFe0.75Mo0.25O3-δ impregnated 430L alloys for efficient fuel oxidation in metal supported solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Zhou, Yucun; Meng, Xie; Yuan, Chun; Luo, Ting; Ye, Xiaofeng; Li, Junliang; Wang, Shaorong; Zhan, Zhongliang

    2014-12-01

    Here we report a novel SrFe0.75Mo0.25O3-δ (SFMO)-430L composite anode for the application in the metal supported solid oxide fuel cells. Such an anode is prepared by coating a thin nano porous and mixed electronic-ionic conducting SFMO layer onto the internal surface of a micron porous 430L alloy backbone. The area specific polarization resistance of the composite anode for hydrogen oxidation can be as low as 0.11 Ω cm2 at 800 °C. The electronic conductivity of the 430L alloy support is found to be critically important for promoting rapid hydrogen oxidation kinetics and attaining such a low polarization resistance as the fuel cell anode. A metal-supported fuel cell with the SFMO impregnated 430L composite anode exhibits outstanding power densities at 800 °C, e.g., 0.81 W cm-2 in hydrogen and 0.31 W cm-2 in iso-octane. Preliminary results show that the present SFMO-430L composite anode exhibits much higher tolerance for coking formation than the traditional Ni-based anode.

  18. Effects of Dopant Metal Variation and Material Synthesis Method on the Material Properties of Mixed Metal Ferrites in Yttria Stabilized Zirconia for Solar Thermochemical Fuel Production

    DOE PAGES

    Leonard, Jeffrey; Reyes, Nichole; Allen, Kyle M.; Randhir, Kelvin; Li, Like; AuYeung, Nick; Grunewald, Jeremy; Rhodes, Nathan; Bobek, Michael; Klausner, James F.

    2015-01-01

    Mixed metal ferrites have shown much promise in two-step solar-thermochemical fuel production. Previous work has typically focused on evaluating a particular metal ferrite produced by a particular synthesis process, which makes comparisons between studies performed by independent researchers difficult. A comparative study was undertaken to explore the effects different synthesis methods have on the performance of a particular material during redox cycling using thermogravimetry. This study revealed that materials made via wet chemistry methods and extended periods of high temperature calcination yield better redox performance. Differences in redox performance between materials made via wet chemistry methods were minimal andmore » these demonstrated much better performance than those synthesized via the solid state method. Subsequently, various metal ferrite samples (NiFe 2 O 4 , MgFe 2 O 4 , CoFe 2 O 4 , and MnFe 2 O 4 ) in yttria stabilized zirconia (8YSZ) were synthesized via coprecipitation and tested to determine the most promising metal ferrite combination. It was determined that 10 wt.% CoFe 2 O 4 in 8YSZ produced the highest and most consistent yields of O 2 and CO. By testing the effects of synthesis methods and dopants in a consistent fashion, those aspects of ferrite preparation which are most significant can be revealed. More importantly, these insights can guide future efforts in developing the next generation of thermochemical fuel production materials.« less

  19. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1992-11-01

    To expand the information base on molecular accessibility in solvent swelled coal, Argonne Premium Coal Samples (APCS) were swelled in polar, basic solvents before and after moisture loss and upon air oxidation. So far studies have been reported on the changes in pore size distribution as a function of temperature when polar basic swelling solvents are used. Additional studies employing EPR spin probe techniques performed on the breaking up of the hydrogen bonding between bedding planes were later confirmed by magnetic resonance imaging at Argonne National Lab and the University of Illinois.

  20. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1990-11-01

    Research continued on the swelling of coal. Changes in the size and number distribution of the accessible regions in five Argonne Premium Coal Samples (APCS No.3, No.4, No.5, No.6, and No.8) upon swelling with the solvents, cyclohexane, toluene, nitrobenzene and pyridine were examined by an EPR spin probe method. It was found that as the basicity of the solvent increased the number and length of the cylindrical pores increased with decreasing rank. The number of cylindrical pores also increased with oxygen content (with decreasing rank) suggesting a destruction of the hydrogen-bond network upon swelling with pyridine. 6 refs.

  1. Separation of metallic residues from the dissolution of a high-burnup BWR fuel using nitrogen trifluoride

    SciTech Connect

    McNamara, Bruce K.; Buck, Edgar C.; Soderquist, Chuck Z.; Smith, Frances N.; Mausolf, Edward J.; Scheele, Randall D.

    2014-03-23

    Nitrogen trifluoride (NF3) was used to fluorinate the metallic residue from the dissolution of a high burnup, boiling water reactor fuel (~70 MWd/kgU). The metallic residue included the noble metal phase (containing ruthenium, rhodium, palladium, technetium, and molybdenum), and smaller amounts of zirconium, selenium, tellurium, and silver. Exposing the noble metal phase to 10% NF3 in argon between 400 and 550°C, removed molybdenum and technetium near 400°C as their volatile fluorides, and ruthenium near 500C as its volatile fluoride. The events were thermally and temporally distinct and the conditions specified are a recipe to separate these transition metals from each other and from the noble metal phase nonvolatile residue. Depletion of the volatile fluorides resulted in substantial exothermicity. Thermal excursion behavior was recorded under non-adiabatic, isothermal conditions that typically minimize heat release. Physical characterization of the metallic noble phase and its thermal behavior are consistent with high kinetic velocity reactions encouraged by the nanoparticulate phase or perhaps catalytic influences of the mixed platinum metals with nearly pure phase structure. Post-fluorination, only two phases were present in the residual nonvolatile fraction. These were identified as a nano-crystalline, metallic palladium cubic phase and a hexagonal rhodium trifluoride (RhF3) phase. The two phases were distinct as the sub-µm crystallites of metallic palladium were in contrast to the RhF3 phase, which grew from the parent nano-crystalline noble-metal phase during fluorination, to acicular crystals exceeding 20-µm in length.

  2. Life prediction of coated and uncoated metallic interconnect for solid oxide fuel cell applications

    NASA Astrophysics Data System (ADS)

    Liu, W. N.; Sun, X.; Stephens, E.; Khaleel, M. A.

    In this paper, we present an integrated experimental and modeling methodology in predicting the life of coated and uncoated metallic interconnect (IC) for solid oxide fuel cell (SOFC) applications. The ultimate goal is to provide cell designer and manufacture with a predictive methodology such that the life of the IC system can be managed and optimized through different coating thickness to meet the overall cell designed life. Crofer 22 APU is used as the example IC material system. The life of coated and uncoated Crofer 22 APU under isothermal cooling was predicted by comparing the predicted interfacial strength and the interfacial stresses induced by the cooling process from the operating temperature to room temperature, together with the measured oxide scale growth kinetics. It was found that the interfacial strength between the oxide scale and the Crofer 22 APU substrate decreases with the growth of the oxide scale, and that the interfacial strength for the oxide scale/spinel coating interface is much higher than that of the oxide scale/Crofer 22 APU substrate interface. As expected, the predicted life of the coated Crofer 22 APU is significantly longer than that of the uncoated Crofer 22 APU.

  3. Nuclear reactor fuel structure containing uranium alloy wires embedded in a metallic matrix plate

    DOEpatents

    Travelli, Armando

    1988-01-01

    A flat or curved plate structure, to be used as fuel in a nuclear reactor, comprises elongated fissionable wires or strips embedded in a metallic continuous non-fissionable matrix plate. The wires or strips are made predominantly of a malleable uranium alloy, such as uranium silicide, uranium gallide or uranium germanide. The matrix plate is made predominantly of aluminum or an aluminum alloy. The wires or strips are located in a single row at the midsurface of the plate, parallel with one another and with the length dimension of the plate. The wires or strips are separated from each other, and from the surface of the plate, by sufficient thicknesses of matrix material, to provide structural integrity and effective fission product retention, under neutron irradiation. This construction makes it safely feasible to provide a high uranium density, so that the uranium enrichment with uranium 235 may be reduced below about 20%, to deter the reprocessing of the uranium for use in nuclear weapons.

  4. Nuclear reactor fuel structure containing uranium alloy wires embedded in a metallic matrix plate

    DOEpatents

    Travelli, A.

    1985-10-25

    A flat or curved plate structure, to be used as fuel in a nuclear reactor, comprises elongated fissionable wires or strips embedded in a metallic continuous non-fissionable matrix plate. The wires or strips are made predominantly of a malleable uranium alloy, such as uranium silicide, uranium gallide or uranium germanide. The matrix plate is made predominantly of aluminum or an aluminum alloy. The wires or strips are located in a single row at the midsurface of the plate, parallel with one another and with the length dimension of the plate. The wires or strips are separated from each other, and from the surface of the plate, by sufficient thicknesses of matrix material, to provide structural integrity and effective fission product retention, under neutron irradiation. This construction makes it safely feasible to provide a high uranium density, so that the uranium enrichment with uranium 235 may be reduced below about 20%, to deter the reprocessing of the uranium for use in nuclear weapons.

  5. Stress and Diffusion in Stored Pu ZPPR Fuel from Alpha Generation

    SciTech Connect

    Charles W. Solbrig; Chad L. Pope; Jason P. Andrus

    2014-07-01

    ZPPR (Zero Power Physics Reactor) is a research reactor that has been used to investigate breeder reactor fuel designs. The reactor has been dismantled but its fuel is still stored there. Of concern are its plutonium containing metal fuel elements which are enclosed in stainless steel cladding with gas space filled with helium–argon gas and welded air tight. The fuel elements which are 5.08 cm by 0.508 cm up to 20.32 cm long (2 in × 0.2 in × 8 in) were manufactured in 1968. A few of these fuel elements have failed releasing contamination raising concern about the general state of the large number of other fuel elements. Inspection of the large number of fuel elements could lead to contamination release so analytical studies have been conducted to estimate the probability of failed fuel elements. This paper investigates the possible fuel failures due to generation of helium in the metal fuel from the decay of Pu and its possible damage to the fuel cladding from metal fuel expansion or from diffusion of helium into the fuel gas space. This paper (1) calculates the initial gas loading in a fuel element and its internal free volume after it has been brought into the atmosphere at ZPPR, (2) shows that the amount of helium generated by decay of Pu over 46 years since manufacture is significantly greater than this initial loading, (3) determines the amount of fuel swelling if the helium stays fixed in the fuel plate and estimates the amount of helium which diffuses out of the fuel plate into the fuel plenum assuming the helium does not remain fixed in the fuel plate but can diffuse to the plenum and possibly through the cladding. Since the literature is not clear as to which possibility occurs, as with Schroedinger’s cat, both possibilities are analyzed. The paper concludes that (1) if the gas generated is fixed in the fuel, then the fuel swelling it can cause would not cause any fuel failure and (2) if the helium does diffuse out of the fuel (in accordance

  6. A rare cause of lateral facial swelling.

    PubMed

    Mohanty, Sujata; Gulati, Ujjwal; Vandana; Singh, Sapna

    2014-01-01

    A case of chronic, recurrent and asymptomatic facial swelling in a young male is presented. Swelling extended from lower midface to upper lateral neck and right commissure to anterior massetric border. History, clinical signs and symptoms and examination pointed towards the benign nature of the swelling. Fine-needle aspiration cytology tapered the diagnostic possibilities to a salivary cyst or pseudocyst. Ultrasonography identified the lesion to contain echogenic fluid with irregular borders. "Tail sign" was absent on contrast magnetic resonance imaging, excluding the involvement of the sublingual gland. Surgical excision of the lesion was done along with submandibular gland as both were in continuity via a bottle-neck tract. Final histopathological diagnosis was that of the submandibular gland extravasation phenomenon. As per the best of our knowledge, it is the first case report of a submandibular gland extravasation causing swelling in a retrograde direction onto the face. PMID:25593883

  7. A rare cause of lateral facial swelling

    PubMed Central

    Mohanty, Sujata; Gulati, Ujjwal; Vandana; Singh, Sapna

    2014-01-01

    A case of chronic, recurrent and asymptomatic facial swelling in a young male is presented. Swelling extended from lower midface to upper lateral neck and right commissure to anterior massetric border. History, clinical signs and symptoms and examination pointed towards the benign nature of the swelling. Fine-needle aspiration cytology tapered the diagnostic possibilities to a salivary cyst or pseudocyst. Ultrasonography identified the lesion to contain echogenic fluid with irregular borders. “Tail sign” was absent on contrast magnetic resonance imaging, excluding the involvement of the sublingual gland. Surgical excision of the lesion was done along with submandibular gland as both were in continuity via a bottle-neck tract. Final histopathological diagnosis was that of the submandibular gland extravasation phenomenon. As per the best of our knowledge, it is the first case report of a submandibular gland extravasation causing swelling in a retrograde direction onto the face. PMID:25593883

  8. Swelling of lignites in organic solvents

    SciTech Connect

    R.G. Makitra; D.V. Bryk

    2008-10-15

    Data on the swelling of Turkish lignites can be summarized using linear multiparameter equations that take into account various properties of solvents. Factors responsible for the amounts of absorbed solvents are the basicity and cohesion energy density of the solvents.

  9. Electrocatalytic Activity of Transition Metal Oxide-Carbon Composites for Oxygen Reduction in Alkaline Batteries and Fuel Cells

    SciTech Connect

    Malkhandi, S; Trinh, P; Manohar, AK; Jayachandrababu, KC; Kindler, A; Prakash, GKS; Narayanan, SR

    2013-06-07

    Conductive transition metal oxides (perovskites, spinels and pyrochlores) are attractive as catalysts for the air electrode in alkaline rechargeable metal-air batteries and fuel cells. We have found that conductive carbon materials when added to transition metal oxides such as calcium-doped lanthanum cobalt oxide, nickel cobalt oxide and calcium-doped lanthanum manganese cobalt oxide increase the electrocatalytic activity of the oxide for oxygen reduction by a factor of five to ten. We have studied rotating ring-disk electrodes coated with (a) various mass ratios of carbon and transition metal oxide, (b) different types of carbon additives and (c) different types of transition metal oxides. Our experiments and analysis establish that in such composite catalysts, carbon is the primary electro- catalyst for the two-electron electro-reduction of oxygen to hydroperoxide while the transition metal oxide decomposes the hydroperoxide to generate additional oxygen that enhances the observed current resulting in an apparent four-electron process. These findings are significant in that they change the way we interpret previous reports in the scientific literature on the electrocatalytic activity of various transition metal oxide- carbon composites for oxygen reduction, especially where carbon is assumed to be an additive that just enhances the electronic conductivity of the oxide catalyst. (C) 2013 The Electrochemical Society. All rights reserved.

  10. Climatology of Global Swell-Atmosphere Interaction

    NASA Astrophysics Data System (ADS)

    Semedo, Alvaro

    2016-04-01

    At the ocean surface wind sea and swell waves coexist. Wind sea waves are locally generated growing waves strongly linked to the overlaying wind field. Waves that propagate away from their generation area, throughout entire ocean basins, are called swell. Swell waves do not receive energy from local wind. Ocean wind waves can be seen as the "gearbox" between the atmosphere and the ocean, and are of critical importance to the coupled atmosphere-ocean system, since they modulate most of the air-sea interaction processes and exchanges, particularly the exchange of momentum. This modulation is most of the times sea-state dependent, i.e., it is a function of the prevalence of one type of waves over the other. The wave age parameter, defined as the relative speed between the peak wave and the wind (c_p⁄U_10), has been largely used in different aspects of the air-sea interaction theory and in practical modeling solutions of wave-atmosphere coupled model systems. The wave age can be used to assess the development of the sea state but also the prevalence (domination) of wind sea or swell waves at the ocean surface. The presence of fast-running waves (swell) during light winds (at high wave age regimes) induces an upward momentum flux, directed from the water surface to the atmosphere. This upward directed momentum has an impact in the lower marine atmospheric boundary layer (MABL): on the one hand it changes the vertical wind speed profile by accelerating the flow at the first few meters (inducing the so called "wave-driven wind"), and on the other hand it changes the overall MABL turbulence structure by limiting the wind shear - in some observed and modeled situations the turbulence is said to have "collapse". The swell interaction with the lower MABL is a function of the wave age but also of the swell steepness, since steeper waves loose more energy into the atmosphere as their energy attenuates. This interaction can be seen as highest in areas where swells are steepest

  11. Impact of reducing sodium void worth on the severe accident response of metallic-fueled sodium-cooled reactors

    SciTech Connect

    Wigeland, R.A.; Turski, R.B.; Pizzica, P.A.

    1994-03-01

    Analyses have performed on the severe accident response of four 90 MWth reactor cores, all designed using the metallic fuel of the Integrated Fast Reactor (IFR) concept. The four core designs have different sodium void worth, in the range of {minus}3$ to 5$. The purpose of the investigation is to determine the improvement in safety, as measured by the severe accident consequences, that can be achieved from a reduction in the sodium void worth for reactor cores designed using the IFR concept.

  12. Emission FTIR analyses of thin microscopic patches of jet fuel residues deposited on heated metal surfaces

    NASA Technical Reports Server (NTRS)

    Lauer, J. L.; Vogel, P.

    1986-01-01

    The relationship of fuel stability to fuel composition and the development of mechanisms for deposit formation were investigated. Fuel deposits reduce heat transfer efficiency and increase resistance to fuel flow and are highly detrimental to aircraft performance. Infrared emission Fourier transform spectroscopy was chosen as the primary method of analysis because it was sensitive enough to be used in-situ on tiny patches of monolayers or of only a few molecular layers of deposits which generally proved completely insoluble in any nondestructive solvents. Deposits of four base fuels were compared; dodecane, a dodecane/tetralin blend, commercial Jet A fuel, and a broadened-properties jet fuel particularly rich in polynuclear aromatics. Every fuel in turn was provided with and without small additions of such additives as thiophene, furan, pyrrole, and copper and iron naphthenates.

  13. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1991-01-01

    The EPR-spin probe method was used to study the swelling of covalently cross-linked 2%, 4%, 6%, 8% and 12% polystyrene-divinyl benzene copolymers, used as models of APCS coal structural elements. The results were compared with swelling studies on APCS coals and confirmed results showing that coal was polymeric, that it had covalent cross-links increasing with rank, that it was structurally anisotropic, and that its swelling was anisotropic. The low temperature swelling of Argonne Premium Coal Samples using solvents of varying polarity was investigated. The variation in the shape of the pore was followed as a function of temperature and swelling solvent polarity. This change in pore structure was attributed to break-up of the hydrogen bonding network in coal by polar solvents. The modification in pore shape from spherical to cylindrical was attributed to anisotropy in hydrogen bond densities. The structural changes in coal pores that occur when APCS coal is dehydrated prior to swelling with polar solvents has been determined. These changes are different from those that occur in the absence of prior dehydration. Most impressive is the huge change that occurs in lignite coal (Beulah-Zap). It appears that this coal has collapsed upon dehydration preventing any spin probe from being trapped in the dehydrated lignite upon swelling. Various sized probes have been studied. A study on the variation in the hydrogen bonding character of the pore wall as the coals are swelled with various polar solvents has also been completed. A statistical analysis of the data has been completed to determine important trends in the data. 9 refs.

  14. Swelling kinetics of tea in hot water.

    PubMed

    Joshi, Bhushan S; Farakte, Raosaheb A; Yadav, Geeta U; Patwardhan, Ashwin W; Singh, Gurmeet

    2016-01-01

    In this study, the swelling kinetics of individual tea particles as well as bed of tea granules were investigated for different types of teas. The swelling experiments involved image analysis and volume measurements of tea particles. Each individual particle shows different swelling characteristics. Separating funnels and cylindrical columns of varying sizes were used to study the changes in volume of tea bed. Swelling in separating funnel was observed to be more than that in column. The effect of temperature, particle size, bed height and vessel diameter were investigated. The extent as well as the rate of swelling is found to increase with rise in temperature (60 to 80 °C) and reduction in particle size. A decrease in swelling is observed with increase in bed height as well as decrease in vessel diameter and vice a versa. About 70 to 75 % swelling occurs in the first 40 to 45 s. Two empirical models viz. Weibull and Peleg were used to fit the experimental data. The rate parameters obtained for a sample T5 at different temperatures were in the range of 0.012 to 0.016. The volume changes of all the teas were compared with their elution behavior, by measuring the absorbance of a diluted sample of brew at 272 nm. The activation energies for the process of tea swelling calculated for T1 (1.2 mm), T5 (2.2 mm) and T5 (0.72 mm) were 14.156, 8.37 and 13.42 kJ/mol respectively. PMID:26787951

  15. An unusual case of acute periorbital swelling.

    PubMed

    Torretta, Sara; Brevi, Alessandra; Pagani, Davide; Pignataro, Lorenzo

    2014-01-01

    Periorbital swelling is frequently encountered in ear, nose, and throat practices and, as it may be secondary to acute sinusitis, delayed diagnosis may lead to significant morbidity. We describe the case of a 24-year-old man with acute ethmoid-maxillary sinusitis and ipsilateral facial swelling particularly involving the periorbital area. We also discuss the workup that led to the formulation of an unusual diagnosis.

  16. Secretory vesicle swelling by atomic force microscopy.

    PubMed

    Cho, Sang-Joon; Jena, Bhanu P

    2006-01-01

    The swelling of secretory vesicles has been implicated in exocytosis, but the underlying mechanism of vesicle swelling remained unknown. Earlier studies from our laboratory demonstrated the association of the alpha-subunit of heterotrimeric GTP-binding protein G(alphai3) with zymogen granule membrane and implicated its involvement in vesicle swelling. Mas7, an active mastoparan analog known to stimulate Gi proteins, was found to stimulate the GTPase activity of isolated zymogen granules and cause swelling. Increase in vesicle size in the presence of GTP, NaF, and Mas7 were irreversible and found to be KCl sensitive. However, Ca2+ had no effect on zymogen granule size. Taken together, these results indicated that zymogen granules, the membrane-bound secretory vesicles in exocrine pancreas, swell in response to GTP mediated by a G(alphai3) protein. Subsequently, our studies demonstrated that the water channel aquaporin-1 (AQP1) is also present at the zymogen granule membrane and participates in rapid GTP-induced and G(alphai3)-mediated vesicular water gating and swelling. Isolated zymogen granules exhibit low basal water permeability. However, exposure of granules to GTP results in a marked potentiation of water entry. Treatment of zymogen granules with the known water channel inhibitor Hg2+ is accompanied by a reversible loss in both the basal and GTP-stimulable water entry and vesicle swelling. Introduction of AQP1-specific antibody raised against the carboxy-terminal domain of AQP1 blocked GTP-stimulable swelling of vesicles. Our results demonstrate that AQPI associated at the zymogen granule membrane is involved in basal GTP-induced and G(alphai3)-mediated rapid gating of water into zymogen granules of the exocrine pancreas.

  17. Swelling kinetics of tea in hot water.

    PubMed

    Joshi, Bhushan S; Farakte, Raosaheb A; Yadav, Geeta U; Patwardhan, Ashwin W; Singh, Gurmeet

    2016-01-01

    In this study, the swelling kinetics of individual tea particles as well as bed of tea granules were investigated for different types of teas. The swelling experiments involved image analysis and volume measurements of tea particles. Each individual particle shows different swelling characteristics. Separating funnels and cylindrical columns of varying sizes were used to study the changes in volume of tea bed. Swelling in separating funnel was observed to be more than that in column. The effect of temperature, particle size, bed height and vessel diameter were investigated. The extent as well as the rate of swelling is found to increase with rise in temperature (60 to 80 °C) and reduction in particle size. A decrease in swelling is observed with increase in bed height as well as decrease in vessel diameter and vice a versa. About 70 to 75 % swelling occurs in the first 40 to 45 s. Two empirical models viz. Weibull and Peleg were used to fit the experimental data. The rate parameters obtained for a sample T5 at different temperatures were in the range of 0.012 to 0.016. The volume changes of all the teas were compared with their elution behavior, by measuring the absorbance of a diluted sample of brew at 272 nm. The activation energies for the process of tea swelling calculated for T1 (1.2 mm), T5 (2.2 mm) and T5 (0.72 mm) were 14.156, 8.37 and 13.42 kJ/mol respectively.

  18. Kinetic and thermodynamic bases to resolve issues regarding conditioning of uranium metal fuels

    SciTech Connect

    Johnson, A.B.; Ballinger, R.G.; Simpson, K.A.

    1994-12-01

    Numerous uranium - bearing fuels are corroding in fuel storage pools in several countries. At facilities where reprocessing is no longer available, dry storage is being evaluated to preclude aqueous corrosion that is ongoing. It is essential that thermodynamic and kinetic factors are accounted for in transitions of corroding uranium-bearing fuels to dry storage. This paper addresses a process that has been proposed to move Hanford N-Reactor fuel from wet storage to dry storage.

  19. A review of composite and metallic bipolar plates in proton exchange membrane fuel cell: Materials, fabrication, and material selection

    NASA Astrophysics Data System (ADS)

    Taherian, Reza

    2014-11-01

    Proton exchange membrane (PEM) fuel cells offer exceptional potential for a clean, efficient, and reliable power source. The bipolar plate (BP) is a key component in this device, as it connects each cell electrically, supplies reactant gases to both anode and cathode, and removes reaction products from the cell. BPs have primarily been fabricated from high-density graphite, but in recent years, much attention has been paid to develop the cost-effective and feasible alternative materials. Recently, two different classes of materials have been attracted attention: metals and composite materials. This paper offers a comprehensive review of the current researches being carried out on the metallic and composite BPs, covering materials and fabrication methods. In this research, the phenomenon of ionic contamination due to the release of the corrosion products of metallic BP and relative impact on the durability as well as performance of PEM fuel cells is extensively investigated. Furthermore, in this paper, upon several effective parameters on commercialization of PEM fuel cells, such as stack cost, weight, volume, durability, strength, ohmic resistance, and ionic contamination, a material selection is performed among the most common BPs currently being used. This material selection is conducted by using Simple Additive Weighting Method (SAWM).

  20. Development of remote disassembly technology for liquid-metal reactor (LMR) fuel

    SciTech Connect

    Bradley, E.C.; Evans, J.H.; Metz, C.F. III; Weil, B.S.

    1990-01-01

    A major objective of the Consolidated Fuel Reprocessing Program (CFRP) is to develop equipment and demonstrate technology to reprocess fast breeder reactor fuel. Experimental work on fuel disassembly cutting methods began in the 1970s. High-power laser cutting was selected as the preferred cutting method for fuel disassembly. Remotely operated development equipment was designed, fabricated, installed, and tested at Oak Ridge National Laboratory (ORNL). Development testing included remote automatic operation, remote maintenance testing, and laser cutting process development. This paper summarizes the development work performed at ORNL on remote fuel disassembly. 2 refs., 1 fig.

  1. Engineering interface and surface of noble metal nanoparticle nanotubes toward enhanced catalytic activity for fuel cell applications.

    PubMed

    Cui, Chun-Hua; Yu, Shu-Hong

    2013-07-16

    In order for fuel cells to have commercial viability as alternative fuel sources, researchers need to develop highly active and robust fuel cell electrocatalysts. In recent years, the focus has been on the design and synthesis of novel catalytic materials with controlled interface and surface structures. Another goal is to uncover potential catalytic activity and selectivity, as well as understand their fundamental catalytic mechanisms. Scientists have achieved great progress in the experimental and theoretical investigation due to the urgent demand for broad commercialization of fuel cells in automotive applications. However, there are still three main problems: cost, performance, and stability. To meet these targets, the catalyst needs to have multisynergic functions. In addition, the composition and structure changes of the catalysts during the reactions still need to be explored. Activity in catalytic nanomaterials is generally controlled by the size, shape, composition, and interface and surface engineering. As such, one-dimensional nanostructures such as nanowires and nanotubes are of special interest. However, these structures tend to lose the nanoparticle morphology and inhibit the use of catalysts in both fuel cell anodes and cathodes. In 2003, Rubinstein and co-workers proposed the idea of nanoparticle nanotubes (NNs), which combine the geometry of nanotubes and the morphology of nanoparticles. This concept gives both the high surface-to-volume ratio and the size effect, which are both appealing in electrocatalyst design. In this Account, we describe our developments in the construction of highly active NNs with unique surface and heterogeneous interface structures. We try to clarify enhanced activity and stability in catalytic systems by taking into account the activity impact factors. We briefly introduce material structural effects on the electrocatalytic reactivity including metal oxide/metal and metal/metal interfaces, dealloyed pure Pt, and mixed Pt

  2. Engineering interface and surface of noble metal nanoparticle nanotubes toward enhanced catalytic activity for fuel cell applications.

    PubMed

    Cui, Chun-Hua; Yu, Shu-Hong

    2013-07-16

    In order for fuel cells to have commercial viability as alternative fuel sources, researchers need to develop highly active and robust fuel cell electrocatalysts. In recent years, the focus has been on the design and synthesis of novel catalytic materials with controlled interface and surface structures. Another goal is to uncover potential catalytic activity and selectivity, as well as understand their fundamental catalytic mechanisms. Scientists have achieved great progress in the experimental and theoretical investigation due to the urgent demand for broad commercialization of fuel cells in automotive applications. However, there are still three main problems: cost, performance, and stability. To meet these targets, the catalyst needs to have multisynergic functions. In addition, the composition and structure changes of the catalysts during the reactions still need to be explored. Activity in catalytic nanomaterials is generally controlled by the size, shape, composition, and interface and surface engineering. As such, one-dimensional nanostructures such as nanowires and nanotubes are of special interest. However, these structures tend to lose the nanoparticle morphology and inhibit the use of catalysts in both fuel cell anodes and cathodes. In 2003, Rubinstein and co-workers proposed the idea of nanoparticle nanotubes (NNs), which combine the geometry of nanotubes and the morphology of nanoparticles. This concept gives both the high surface-to-volume ratio and the size effect, which are both appealing in electrocatalyst design. In this Account, we describe our developments in the construction of highly active NNs with unique surface and heterogeneous interface structures. We try to clarify enhanced activity and stability in catalytic systems by taking into account the activity impact factors. We briefly introduce material structural effects on the electrocatalytic reactivity including metal oxide/metal and metal/metal interfaces, dealloyed pure Pt, and mixed Pt

  3. Impact of Fission Products Impurity on the Plutonium Content of Metal- and Oxide- Fuels in Sodium Cooled Fast Reactors

    SciTech Connect

    Hikaru Hiruta; Gilles Youinou

    2013-09-01

    This short report presents the neutronic analysis to evaluate the impact of fission product impurity on the Pu content of Sodium-cooled Fast Reactor (SFR) metal- and oxide- fuel fabrication. The similar work has been previously done for PWR MOX fuel [1]. The analysis will be performed based on the assumption that the separation of the fission products (FP) during the reprocessing of UOX spent nuclear fuel assemblies is not perfect and that, consequently, a certain amount of FP goes into the Pu stream used to fabricate SFR fuels. Only non-gaseous FPs have been considered (see the list of 176 isotopes considered in the calculations in Appendix 1 of Reference 1). Throughout of this report, we define the mixture of Pu and FPs as PuFP. The main objective of this analysis is to quantify the increase of the Pu content of SFR fuels necessary to maintain the same average burnup at discharge independently of the amount of FP in the Pu stream, i.e. independently of the PuFP composition. The FP losses are considered element-independent, i.e., for example, 1% of FP losses mean that 1% of all non-gaseous FP leak into the Pu stream.

  4. Electrochemical study of lithiated transition metal oxide composite for single layer fuel cell

    NASA Astrophysics Data System (ADS)

    Hu, Huiqing; Lin, Qizhao; Muhammad, Afzal; Zhu, Bin

    2015-07-01

    This study analyzed the effect of various semiconductors of transition metal oxides in modified lithiated NiO on the electrochemical performance of a single layer fuel cell (SLFC). A typical ionic conductor Ce0.8Sm0.2O2-δ (SDC) and three types of semiconductors Li0.3Ni0.6Cu0.07Sr0.03O2-δ (LNCuS), Li0.3Ni0.6Mn0.07Sr0.03O2-δ (LNMnS) and Li0.3Ni0.6Co0.07Sr0.03O2-δ (LNCoS), were the fundamental components of the SLFCs. The components were characterized by using X-ray diffraction (XRD), a scanning electron microscope (SEM), and an energy-dispersive X-ray spectrometer (EDS). The stability of the synthesized materials was evaluated using thermal gravity analysis (TGA). The ohmic resistances at 500 °C were 0.36, 0.48 and 0.58 Ω cm2 for 6SDC-4LNMnS, 6SDC-4LNCoS and 6SDC-4LNCuS, respectively. Among the three SLFCs, the single cell with 6SDC-4LNMnS achieves the highest power density (422 mW cm-2) but the lowest temperature stability, while the single cell with 6SDC-4LNCuS achieved the lowest power density (331 mW cm-2) but the highest temperature stability during the operation temperature.

  5. A methodology for investigating new nonprecious metal catalysts for PEM fuel cells.

    PubMed

    Susac, D; Sode, A; Zhu, L; Wong, P C; Teo, M; Bizzotto, D; Mitchell, K A R; Parsons, R R; Campbell, S A

    2006-06-01

    This paper reports an approach to investigate metal-chalcogen materials as catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells. The methodology is illustrated with reference to Co-Se thin films prepared by magnetron sputtering onto a glassy-carbon substrate. Scanning Auger microscopy (SAM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) have been used, in parallel with electrochemical activity and stability measurements, to assess how the electrochemical performance relates to chemical composition. It is shown that Co-Se thin films with varying Se are active for oxygen reduction, although the open circuit potential (OCP) is lower than for Pt. A kinetically controlled process is observed in the potential range 0.5-0.7 V (vs reversible hydrogen electrode) for the thin-film catalysts studied. An initial exposure of the thin-film samples to an acid environment served as a pretreatment, which modified surface composition prior to activity measurements with the rotating disk electrode (RDE) method. Based on the SAM characterization before and after electrochemical tests, all surfaces demonstrating activity are dominated by chalcogen. XRD shows that the thin films have nanocrystalline character that is based on a Co(1-x)Se phase. Parallel studies on Co-Se powder supported on XC72R carbon show comparable OCP, Tafel region, and structural phase as for the thin-film model catalysts. A comparison for ORR activity has also been made between this Co-Se powder and a commercial Pt catalyst.

  6. Visible light active, nano-architectured metal oxide photo-catalysts for solar fuel applications

    NASA Astrophysics Data System (ADS)

    LaTempa, Thomas Joseph, Jr.

    Large-scale implementation of renewable energy sources such as solar requires the development of an efficient energy capture, conversion and storage scheme. Harnessing solar energy to create storable fuels, i.e., solar fuels, provides a unique strategy to meet this objective. In this regard, hydrogen generation through water photoelectrolysis and methane generation via the photocatalytic conversion of carbon dioxide and water vapor are investigated. The primary motivation of this work lies in the development of efficient, low cost materials for solar fuel applications. Metal oxide semiconductors such as n-type titanium dioxide (TiO 2) have generated significant interest in the scientific community due to their low cost, stability and high photocatalytic activity under band gap illumination. The implementation of nano-structured materials has significantly enhanced the conversion efficiency obtained with TiO2 in applications such as water photoelectrolysis. Despite these advancements, TiO2 has an inherently poor photoresponse due its wide band gap (3.0-3.2 eV), which accounts for ≈ 5% of the solar spectrum energy. Therefore, the primary objective of this work is to develop materials with a photocatalytic activity approaching that of TiO2, while shifting the photo-response to harness the visible light portion of the solar spectrum. Two differing approaches are evaluated in this work to meet this objective. Hematite (alpha-Fe2O3) has a band gap ≈ 2.2 eV, well suited for capturing solar energy, but suffers from intrinsically poor electrical characteristics. To overcome these limitations, iron oxide nanotubes were developed using a temperature controlled anodization technique. This provides greater control over the film morphology to create high aspect ratio nano-structures approximately 1-4 mum in length, sufficient to harness solar energy, with a wall thickness approaching 10 nm to improve the electrical characteristics for photocatalytic application. The

  7. Thermal Transport in Porous Media with Application to Fuel Cell Diffusion Media and Metal Foams

    NASA Astrophysics Data System (ADS)

    Sadeghi, Ehsan

    Transport phenomena in high porosity open-cell fibrous structures have been the focus of many recent industrial and academic investigations. Unique features of these structures such as relatively low cost, ultra-low density, high surface area to volume ratio, and the ability to mix the passing fluid make them excellent candidates for a variety of thermofluid applications including fuel cells, compact heat exchangers and cooling of microelectronics. This thesis contributes to improved understanding of thermal transport phenomena in fuel cell gas diffusion layers (GDLs) and metal foams and describes new experimental techniques and analytic models to characterize and predict effective transport properties. Heat transfer through the GDL is a key process in the design and operation of a proton exchange membrane (PEM) fuel cell. The analysis of this process requires determination of the effective thermal conductivity as well as the thermal contact resistance (TCR) associated with the interface between the GDL and adjacent surfaces/ layers. The effective thermal conductivity significantly differs in through-plane and in-plane directions due to anisotropy of the GDL micro-structure. Also, the high porosity of GDLs makes the contribution of TCR against the heat flow through the medium more pronounced. A test bed was designed and built to measure the thermal contact resistance and effective thermal conductivity in both through-plane and in-plane directions under vacuum and ambient conditions. The developed experimental program allows the separation of effective thermal conductivity and thermal contact resistance. For GDLs, measurements are performed under a wide range of compressive loads using Toray carbon paper samples. To study the effect of cyclic compression, which may happen during the operation of a fuel cell stack, measurements are performed on the thermal and structural properties of GDL at different loading-unloading cycles. The static compression measurements are

  8. Diffusion Barrier Selection from Refractory Metals (Zr, Mo and Nb) via Interdiffusion Investigation for U-Mo RERTR Fuel Alloy

    SciTech Connect

    K. Huang; C. Kammerer; D. D. Keiser, Jr.; Y. H. Sohn

    2014-04-01

    U-Mo alloys are being developed as low enrichment monolithic fuel under the Reduced Enrichment for Research and Test Reactor (RERTR) Program. Diffusional interactions between the U-Mo fuel alloy and Al-alloy cladding within the monolithic fuel plate construct necessitate incorporation of a barrier layer. Fundamentally, a diffusion barrier candidate must have good thermal conductivity, high melting point, minimal metallurgical interaction, and good irradiation performance. Refractory metals, Zr, Mo, and Nb are considered based on their physical properties, and the diffusion behavior must be carefully examined first with U-Mo fuel alloy. Solid-to-solid U-10wt.%Mo vs. Mo, Zr, or Nb diffusion couples were assembled and annealed at 600, 700, 800, 900 and 1000 degrees C for various times. The interdiffusion microstructures and chemical composition were examined via scanning electron microscopy and electron probe microanalysis, respectively. For all three systems, the growth rate of interdiffusion zone were calculated at 1000, 900 and 800 degrees C under the assumption of parabolic growth, and calculated for lower temperature of 700, 600 and 500 degrees C according to Arrhenius relationship. The growth rate was determined to be about 10 3 times slower for Zr, 10 5 times slower for Mo and 10 6 times slower for Nb, than the growth rates reported for the interaction between the U-Mo fuel alloy and pure Al or Al-Si cladding alloys. Zr, however was selected as the barrier metal due to a concern for thermo- mechanical behavior of UMo/Nb interface observed from diffusion couples, and for ductile-to-brittle transition of Mo near room temperature.

  9. Morphing of geometric composites via residual swelling.

    PubMed

    Pezzulla, Matteo; Shillig, Steven A; Nardinocchi, Paola; Holmes, Douglas P

    2015-08-01

    Understanding and controlling the shape of thin, soft objects has been the focus of significant research efforts among physicists, biologists, and engineers in the last decade. These studies aim to utilize advanced materials in novel, adaptive ways such as fabricating smart actuators or mimicking living tissues. Here, we present the controlled growth-like morphing of 2D sheets into 3D shapes by preparing geometric composite structures that deform by residual swelling. The morphing of these geometric composites is dictated by both swelling and geometry, with diffusion controlling the swelling-induced actuation, and geometric confinement dictating the structure's deformed shape. Building on a simple mechanical analog, we present an analytical model that quantitatively describes how the Gaussian and mean curvatures of a thin disk are affected by the interplay among geometry, mechanics, and swelling. This model is in excellent agreement with our experiments and numerics. We show that the dynamics of residual swelling is dictated by a competition between two characteristic diffusive length scales governed by geometry. Our results provide the first 2D analog of Timoshenko's classical formula for the thermal bending of bimetallic beams - our generalization explains how the Gaussian curvature of a 2D geometric composite is affected by geometry and elasticity. The understanding conferred by these results suggests that the controlled shaping of geometric composites may provide a simple complement to traditional manufacturing techniques. PMID:26076671

  10. Swelling and Contraction of Corn Mitochondria 1

    PubMed Central

    Stoner, C. D.; Hanson, J. B.

    1966-01-01

    A survey has been made of the properties of corn mitochondria in swelling and contraction. The mitochondria swell spontaneously in KCl but not in sucrose. Aged mitochondria will swell rapidly in sucrose if treated with citrate or EDTA. Swelling does not impair oxidative phosphorylation if bovine serum albumin is present. Contraction can be maintained or initiated with ATP + Mg or an oxidizable substrate, contraction being more rapid with the substrate. Magnesium is not required for substrate powered contraction. Contraction powered by ATP is accompanied by the release of phosphate. Oligomycin inhibits both ATP-powered contraction and the release of phosphate. However, it does not affect substrate-powered contraction. Substrate powered contraction is inhibited by electron-transport inhibitors. The uncoupler, carbonyl cyanide m-chlorophenyl hydrazone, accelerates swelling and inhibits both ATP-and substrate-powered contraction. However, the concentrations required are well in excess of those required to produce uncoupling and to accelerate adenosine triphosphatase; the concentrations required inhibit respiration in a phosphorylating medium. Phosphate is a very effective inhibitor of succinate-powered contraction. Neither oligomycin nor Mg affects the phosphate inhibition. Phosphate is less inhibitory with the ATP-powered contraction. The results are discussed in terms of a hypothesis that contraction is associated with a nonphosphorylated high energy intermediate of oxidative phosphorylation. Images PMID:16656248

  11. Swell-Dissipation Function for Wave Models

    NASA Astrophysics Data System (ADS)

    Babanin, A.

    2012-04-01

    In the paper, we will investigate swell attenuation due to production of turbulence by the wave orbital motion. Theoreticaly, potential waves cannot generate the vortex motion, but the scale considerations indicate that if the steepness of waves is not too small, the Reynolds number can exceed the critical values. This means that in presence of initial non-potential disturbances the orbital velocities can generate the vortex motion and turbulence. This problem was investigated by laboratory means, numerical simulations and field observations. As a sink of wave energy, such dissipation is small in presence of wave breaking, but is essential for swell. Swell prediction by spectral wave models is often poor, but is important for offshore and maritime industry, and across a broad range of oceanographic and air-sea interaction applications. Based on the research of wave-induced turbulence, new swell-dissipation function is proposed. It agrees well with satellite observations of long-distance swell propagation and has been employed and tested in spectral wave models.

  12. Partitioning of metal species during an enriched fuel combustion experiment. speciation in the gaseous and particulate phases.

    PubMed

    Pavageau, Marie-Pierre; Morin, Anne; Seby, Fabienne; Guimon, Claude; Krupp, Eva; Pécheyran, Christophe; Poulleau, Jean; Donard, Olivier F X

    2004-04-01

    Combustion processes are the most important source of metal in the atmosphere and need to be better understood to improve flue gas treatment and health impact studies. This combustion experiment was designed to study metal partitioning and metal speciation in the gaseous and particulate phases. A light fuel oil was enriched with 15 organometallic compounds of the following elements: Pb, Hg, As, Cu, Zn, Cd, Se, Sn, Mn, V, Tl, Ni, Co, Cr, and Sb. The resulting mixture was burnt in a pilot-scale fuel combustion boiler under controlled conditions. After filtration of the particles, the gaseous species were sampled in the stack through a heated sampling tube simultaneously by standardized washing bottles-based sampling techniques and cryogenically. The cryogenic samples were collected at -80 degrees C for further speciation analysis by LT/GC-ICPMS. Three species of selenium and two of mercury were evidenced as volatile species in the flue gas. Thermodynamic predictions and experiments suggest the following volatile metal species to be present in the flue gas: H2Se, CSSe, CSe2, SeCl2, Hg(0), and HgCl2. Quantification of volatile metal species in comparison between cryogenic techniques and the washing bottles-based sampling method is also discussed. Concerning metal partitioning, the results indicated that under these conditions, at least 60% (by weight) of the elements Pb, Sn, Cu, Co, Tl, Mn, V, Cr, Ni, Zn, Cd, and Sb mixed to the fuel were found in the particulate matter. For As and Se, 37 and 17%, respectively, were detected in the particles, and no particulate mercury was found. Direct metal speciation in particles was performed by XPS allowing the determination of the oxidation state of the following elements: Sb(V), Tl(III), Mn(IV), Cd(II), Zn(II), Cr(III), Ni(II), Co(II), V(V), and Cu(II). Water soluble species of inorganic Cr, As, and Se in particulate matter were determined by HPLC/ICP-MS and identified in the oxidation state Cr(III), As(V), and Se(IV).

  13. Swelling, mechanical and friction properties of PVA/PVP hydrogels after swelling in osmotic pressure solution.

    PubMed

    Shi, Yan; Xiong, Dangsheng; Liu, Yuntong; Wang, Nan; Zhao, Xiaoduo

    2016-08-01

    The potential of polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) hydrogels as articular cartilage replacements was in vitro evaluated by using a macromolecule-based solution to mimic the osmotic environment of cartilage tissue. The effects of osmotic pressure solution on the morphology, crystallinity, swelling, mechanical and friction properties of PVA/PVP hydrogels were investigated by swelling them in non-osmotic and osmotic pressure solutions. The results demonstrated that swelling ratio and equilibrium water content were greatly reduced by swelling in osmotic solution, and the swelling process was found to present pseudo-Fickian diffusion character. The crystallization degree of hydrogels after swelling in osmotic solution increased more significantly when it compared with that in non-osmotic solution. After swelling in osmotic solution for 28days, the compressive tangent modulus and storage modulus of hydrogels were significantly increased, and the low friction coefficient was reduced. However, after swelling in the non-osmotic solution, the compressive tangent modulus and friction coefficient of hydrogels were comparable with those of as-prepared hydrogels. The better material properties of hydrogels in vivo than in vitro evaluation demonstrated their potential application in cartilage replacement.

  14. Historical reconstruction of major pollutant levels in the Hudson-Raritan Basin: 1880-1980. Volume 2. Heavy metals and fossil fuels. Technical memo

    SciTech Connect

    Ayers, R.U.; Ayers, L.W.

    1988-10-01

    Volume 2: Metals covers the sources, production processes, consumptive uses of and environmental emissions of eight heavy metals (silver, arsenic, cadmium, chromium, copper, mercury, lead, zinc). Included are sections that discuss the part fossil fuel combustion plays in the overall pollution loading of Hudson-Raritan Basin.

  15. Metal organic chemical vapor deposition of environmental barrier coatings for the inhibition of solid deposit formation from heated jet fuel

    NASA Astrophysics Data System (ADS)

    Mohan, Arun Ram

    Solid deposit formation from jet fuel compromises the fuel handling system of an aviation turbine engine and increases the maintenance downtime of an aircraft. The deposit formation process depends upon the composition of the fuel, the nature of metal surfaces that come in contact with the heated fuel and the operating conditions of the engine. The objective of the study is to investigate the effect of substrate surfaces on the amount and nature of solid deposits in the intermediate regime where both autoxidation and pyrolysis play an important role in deposit formation. A particular focus has been directed to examining the effectiveness of barrier coatings produced by metal organic chemical vapor deposition (MOCVD) on metal surfaces for inhibiting the solid deposit formation from jet fuel degradation. In the first part of the experimental study, a commercial Jet-A sample was stressed in a flow reactor on seven different metal surfaces: AISI316, AISI 321, AISI 304, AISI 347, Inconel 600, Inconel 718, Inconel 750X and FecrAlloy. Examination of deposits by thermal and microscopic analysis shows that the solid deposit formation is influenced by the interaction of organosulfur compounds and autoxidation products with the metal surfaces. The nature of metal sulfides was predicted by Fe-Ni-S ternary phase diagram. Thermal stressing on uncoated surfaces produced coke deposits with varying degree of structural order. They are hydrogen-rich and structurally disordered deposits, spherulitic deposits, small carbon particles with relatively ordered structures and large platelets of ordered carbon structures formed by metal catalysis. In the second part of the study, environmental barrier coatings were deposited on tube surfaces to inhibit solid deposit formation from the heated fuel. A new CVD system was configured by the proper choice of components for mass flow, pressure and temperature control in the reactor. A bubbler was designed to deliver the precursor into the reactor

  16. Postoperative pectoral swelling after shoulder arthroscopy

    PubMed Central

    ERCIN, ERSIN; BILGILI, MUSTAFA GOKHAN; ONES, HALIL NADIR; KURAL, CEMAL

    2015-01-01

    Fluid extravasation is possibly the most common complication of shoulder arthroscopy. Shoulder arthroscopy can lead to major increases in the compartment pressure of adjacent muscles and this phenomenon is significant when an infusion pump is used. This article describes a case of pectoral swelling due to fluid extravasation after shoulder arthroscopy. A 24-year-old male underwent an arthroscopic Bankart repair for recurrent shoulder dislocation. The surgery was performed in the beach chair position and lasted two hours. At the end of the procedure, the patient was found to have left pectoral swelling. A chest radiography showed no abnormality. Pectoral swelling due to fluid extravasation after shoulder arthroscopy has not previously been documented. PMID:26889473

  17. Swelling of pH-sensitive hydrogels.

    PubMed

    Drozdov, A D; deClaville Christiansen, J

    2015-02-01

    A model is derived for the elastic response of polyelectrolyte gels subjected to unconstrained and constrained swelling. A gel is treated as a three-phase medium consisting of a solid phase (polymer network), solvent (water), and solutes (mobile ions). Transport of solvent and solutes is modeled as their diffusion through the network accelerated by an electric field formed by ions and accompanied by chemical reactions (dissociation of functional groups attached to the chains). Constitutive equations (including the van't Hoff law for ionic pressure and the Henderson-Hasselbach equation for ionization of chains) are derived by means of the free energy imbalance inequality. Good agreement is demonstrated between equilibrium swelling diagrams on several pH-sensitive gels and results of simulation. It is revealed that swelling of polyelectrolyte gels is driven by electrostatic repulsion of bound charges, whereas the effect of ionic pressure is of secondary importance. PMID:25768503

  18. Swelling of p H -sensitive hydrogels

    NASA Astrophysics Data System (ADS)

    Drozdov, A. D.; deClaville Christiansen, J.

    2015-02-01

    A model is derived for the elastic response of polyelectrolyte gels subjected to unconstrained and constrained swelling. A gel is treated as a three-phase medium consisting of a solid phase (polymer network), solvent (water), and solutes (mobile ions). Transport of solvent and solutes is modeled as their diffusion through the network accelerated by an electric field formed by ions and accompanied by chemical reactions (dissociation of functional groups attached to the chains). Constitutive equations (including the van't Hoff law for ionic pressure and the Henderson-Hasselbach equation for ionization of chains) are derived by means of the free energy imbalance inequality. Good agreement is demonstrated between equilibrium swelling diagrams on several pH-sensitive gels and results of simulation. It is revealed that swelling of polyelectrolyte gels is driven by electrostatic repulsion of bound charges, whereas the effect of ionic pressure is of secondary importance.

  19. Swelling and Stress Relaxation in Portland Brownstone

    NASA Astrophysics Data System (ADS)

    Jimenez, I.; Scherer, G.

    2003-04-01

    Portland Brownstone (PB) is an arkose sandstone extensively used in the northeast-ern USA during the nineteenth century. This reddish-brown stone contains a fraction of swelling clays that are thought to contribute to its degradation upon cycles of wet-ting and drying. During drying events, contraction of the drying surface leads to stresses approaching the tensile strength of the stone. However, we have found that the magnitude of these stresses is limited by the ability of the stone to undergo stress relaxation. In this paper we describe novel methods to determine the magnitude of the stresses and the rate at which they develop and relax. We also discuss the influ-ence of surfactants on the magnitude of swelling and the rate of the stress relaxation of PB. The implications of our findings for the understanding of damage due to swelling of clays are discussed.

  20. Electron probe microanalysis of a METAPHIX UPuZr metallic alloy fuel irradiated to 7.0 at.% burn-up

    NASA Astrophysics Data System (ADS)

    Brémier, S.; Inagaki, K.; Capriotti, L.; Poeml, P.; Ogata, T.; Ohta, H.; Rondinella, V. V.

    2016-11-01

    The METAPHIX project is a collaboration between CRIEPI and JRC-ITU investigating safety and performance of a closed fuel cycle option based on fast reactor metal alloy fuels containing Minor Actinides (MA). The aim of the project is to investigate the behaviour of this type of fuel and demonstrate the transmutation of MA under irradiation. A UPuZr metallic fuel sample irradiated to a burn-up of 7 at.% was examined by electron probe microanalysis. The fuel sample was extensively characterised qualitatively and quantitatively using elemental X-ray imaging and point analysis techniques. The analyses reveal a significant redistribution of the fuel components along the fuel radius highlighting a nearly complete depletion of Zr in the central part of the fuel. Numerous rare earth and fission products secondary phases are present in various compositions. Fuel cladding chemical interaction was observed with creation of a number of intermediary layers affecting a cladding depth of 15-20 μm and migration of cladding elements to the fuel.

  1. Metallic elements in fossil fuel combustion products: amounts and form of emissions and evaluation of carcinogenicity and mutagenicity.

    PubMed Central

    Vouk, V B; Piver, W T

    1983-01-01

    Metallic elements contained in coal, oil and gasoline are mobilized by combustion processes and may be emitted into the atmosphere, mainly as components of submicron particles. The information about the amounts, composition and form of metal compounds is reviewed for some fuels and combustion processes. Since metal compounds are always contained in urban air pollutants, they have to be considered whenever an evaluation of biological impact of air pollutants is made. The value of currently used bioassays for the evaluation of the role of trace metal compounds, either as major biologically active components or as modifiers of biological effects of organic compounds is assessed. The whole animal bioassays for carcinogenicity do not seem to be an appropriate approach. They are costly, time-consuming and not easily amenable to the testing of complex mixtures. Some problems related to the application and interpretation of short-term bioassays are considered, and the usefulness of such bioassays for the evaluation of trace metal components contained in complex air pollution mixtures is examined. PMID:6337825

  2. Evaluation of Metal Halide, Plasma, and LED Lighting Technologies for a Hydrogen Fuel Cell Mobile Light (H 2 LT)

    SciTech Connect

    Miller, L. B.; Donohoe, S. P.; Jones, M. H.; White, W. A.; Klebanoff, L. E.; Velinsky, S. A.

    2015-04-22

    This article reports on the testing and comparison of a prototype hydrogen fuel cell light tower (H2LT) and a conventional diesel-powered metal halide light trailer for use in road maintenance and construction activities. The prototype was originally outfitted with plasma lights and then with light-emitting diode (LED) luminaires. Light output and distribution, lighting energy efficiency (i.e., efficacy), power source thermal efficiency, and fuel costs are compared. The metal halide luminaires have 2.2 and 3.1 times more light output than the plasma and LED luminaires, respectively, but they require more power/lumen to provide that output. The LED luminaires have 1.6 times better light efficacy than either the metal halide or plasma luminaires. The light uniformity ratios produced by the plasma and LED towers are acceptable. The fuel cell thermal efficiency at the power required to operate the plasma lights is 48%, significantly higher than the diesel generator efficiency of 23% when operating the metal halide lights. Due to the increased efficiency of the fuel cell and the LED lighting, the fuel cost per lumen-hour of the H2LT is 62% of the metal halide diesel light tower assuming a kilogram of hydrogen is twice the cost of a gallon of diesel fuel.

  3. Swelling of plasma-polymerized tetrafluoroethylene films

    SciTech Connect

    Butler, M.A.; Buss, R.J.; Seager, C.H. )

    1991-11-25

    Swelling of micrometer thick-films of plasma-polymerized tetrafluoroethylene has been measured for a range of solvents using an optical-interferometric technique. For low gas-phase concentrations of the solvent, the swelling is found to correlate with the ionization potential of the solvent. Photo-thermal deflection spectroscopy of the films shows optical absorption in the infrared, which changes with exposure to different solvents. Both of these results suggest weak electron transfer from the solvent to the polymer as the dominant interaction mechanism.

  4. Efficient solar-driven synthesis, carbon capture, and desalinization, STEP: solar thermal electrochemical production of fuels, metals, bleach.

    PubMed

    Licht, S

    2011-12-15

    STEP (solar thermal electrochemical production) theory is derived and experimentally verified for the electrosynthesis of energetic molecules at solar energy efficiency greater than any photovoltaic conversion efficiency. In STEP the efficient formation of metals, fuels, chlorine, and carbon capture is driven by solar thermal heated endothermic electrolyses of concentrated reactants occuring at a voltage below that of the room temperature energy stored in the products. One example is CO(2) , which is reduced to either fuels or storable carbon at a solar efficiency of over 50% due to a synergy of efficient solar thermal absorption and electrochemical conversion at high temperature and reactant concentration. CO(2) -free production of iron by STEP, from iron ore, occurs via Fe(III) in molten carbonate. Water is efficiently split to hydrogen by molten hydroxide electrolysis, and chlorine, sodium, and magnesium from molten chlorides. A pathway is provided for the STEP decrease of atmospheric carbon dioxide levels to pre-industial age levels in 10 years.

  5. Emissions from a Diesel Engine using Fe-based Fuel Additives and a Sintered Metal Filtration System.

    PubMed

    Bugarski, Aleksandar D; Hummer, Jon A; Stachulak, Jozef S; Miller, Arthur; Patts, Larry D; Cauda, Emanuele G

    2016-03-01

    A series of laboratory tests were conducted to assess the effects of Fe-containing fuel additives on aerosols emitted by a diesel engine retrofitted with a sintered metal filter (SMF) system. Emission measurements performed upstream and downstream of the SMF system were compared, for cases when the engine was fueled with neat ultralow sulfur diesel (ULSD) and with ULSD treated with two formulations of additives containing Fe-based catalysts. The effects were assessed for four steady-state engine operating conditions and one transient cycle. The results showed that the SMF system reduced the average total number and surface area concentrations of aerosols by more than 100-fold. The total mass and elemental carbon results confirmed that the SMF system was indeed very effective in the removal of diesel aerosols. When added at the recommended concentrations (30 p.p.m. of iron), the tested additives had minor adverse impacts on the number, surface area, and mass concentrations of filter-out (FOut) aerosols. For one of the test cases, the additives may have contributed to measurable concentrations of engine-out (EOut) nucleation mode aerosols. The additives had only a minor impact on the concentration and size distribution of volatile and semi-volatile FOut aerosols. Metal analysis showed that the introduction of Fe with the additives substantially increased Fe concentration in the EOut, but the SMF system was effective in removal of Fe-containing aerosols. The FOut Fe concentrations for all three tested fuels were found to be much lower than the corresponding EOut Fe concentrations for the case of untreated ULSD fuel. The results support recommendations that these additives should not be used in diesel engines unless they are equipped with exhaust filtration systems. Since the tested SMF system was found to be very efficient in removing Fe introduced by the additives, the use of these additives should not result in a measurable increase in emissions of de novo generated

  6. Emissions from a Diesel Engine using Fe-based Fuel Additives and a Sintered Metal Filtration System.

    PubMed

    Bugarski, Aleksandar D; Hummer, Jon A; Stachulak, Jozef S; Miller, Arthur; Patts, Larry D; Cauda, Emanuele G

    2016-03-01

    A series of laboratory tests were conducted to assess the effects of Fe-containing fuel additives on aerosols emitted by a diesel engine retrofitted with a sintered metal filter (SMF) system. Emission measurements performed upstream and downstream of the SMF system were compared, for cases when the engine was fueled with neat ultralow sulfur diesel (ULSD) and with ULSD treated with two formulations of additives containing Fe-based catalysts. The effects were assessed for four steady-state engine operating conditions and one transient cycle. The results showed that the SMF system reduced the average total number and surface area concentrations of aerosols by more than 100-fold. The total mass and elemental carbon results confirmed that the SMF system was indeed very effective in the removal of diesel aerosols. When added at the recommended concentrations (30 p.p.m. of iron), the tested additives had minor adverse impacts on the number, surface area, and mass concentrations of filter-out (FOut) aerosols. For one of the test cases, the additives may have contributed to measurable concentrations of engine-out (EOut) nucleation mode aerosols. The additives had only a minor impact on the concentration and size distribution of volatile and semi-volatile FOut aerosols. Metal analysis showed that the introduction of Fe with the additives substantially increased Fe concentration in the EOut, but the SMF system was effective in removal of Fe-containing aerosols. The FOut Fe concentrations for all three tested fuels were found to be much lower than the corresponding EOut Fe concentrations for the case of untreated ULSD fuel. The results support recommendations that these additives should not be used in diesel engines unless they are equipped with exhaust filtration systems. Since the tested SMF system was found to be very efficient in removing Fe introduced by the additives, the use of these additives should not result in a measurable increase in emissions of de novo generated

  7. Emissions from a Diesel Engine using Fe-based Fuel Additives and a Sintered Metal Filtration System

    PubMed Central

    Bugarski, Aleksandar D.; Hummer, Jon A.; Stachulak, Jozef S.; Miller, Arthur; Patts, Larry D.; Cauda, Emanuele G.

    2015-01-01

    A series of laboratory tests were conducted to assess the effects of Fe-containing fuel additives on aerosols emitted by a diesel engine retrofitted with a sintered metal filter (SMF) system. Emission measurements performed upstream and downstream of the SMF system were compared, for cases when the engine was fueled with neat ultralow sulfur diesel (ULSD) and with ULSD treated with two formulations of additives containing Fe-based catalysts. The effects were assessed for four steady-state engine operating conditions and one transient cycle. The results showed that the SMF system reduced the average total number and surface area concentrations of aerosols by more than 100-fold. The total mass and elemental carbon results confirmed that the SMF system was indeed very effective in the removal of diesel aerosols. When added at the recommended concentrations (30 p.p.m. of iron), the tested additives had minor adverse impacts on the number, surface area, and mass concentrations of filter-out (FOut) aerosols. For one of the test cases, the additives may have contributed to measurable concentrations of engine-out (EOut) nucleation mode aerosols. The additives had only a minor impact on the concentration and size distribution of volatile and semi-volatile FOut aerosols. Metal analysis showed that the introduction of Fe with the additives substantially increased Fe concentration in the EOut, but the SMF system was effective in removal of Fe-containing aerosols. The FOut Fe concentrations for all three tested fuels were found to be much lower than the corresponding EOut Fe concentrations for the case of untreated ULSD fuel. The results support recommendations that these additives should not be used in diesel engines unless they are equipped with exhaust filtration systems. Since the tested SMF system was found to be very efficient in removing Fe introduced by the additives, the use of these additives should not result in a measurable increase in emissions of de novo generated

  8. Separation of toxic metal ions, hydrophilic hydrocarbons, hydrophobic fuel and halogenated hydrocarbons and recovery of ethanol from a process stream

    DOEpatents

    Kansa, E.J.; Anderson, B.L.; Wijesinghe, A.M.; Viani, B.E.

    1999-05-25

    This invention provides a process to tremendously reduce the bulk volume of contaminants obtained from an effluent stream produced subsurface remediation. The chemicals used for the subsurface remediation are reclaimed for recycling to the remediation process. Additional reductions in contaminant bulk volume are achieved by the ultra-violet light destruction of halogenated hydrocarbons, and the complete oxidation of hydrophobic fuel hydrocarbons and hydrophilic hydrocarbons. The contaminated bulk volume will arise primarily from the disposal of the toxic metal ions. The entire process is modular, so if there are any technological breakthroughs in one or more of the component process modules, such modules can be readily replaced. 3 figs.

  9. Separation of toxic metal ions, hydrophilic hydrocarbons, hydrophobic fuel and halogenated hydrocarbons and recovery of ethanol from a process stream

    DOEpatents

    Kansa, Edward J.; Anderson, Brian L.; Wijesinghe, Ananda M.; Viani, Brian E.

    1999-01-01

    This invention provides a process to tremendously reduce the bulk volume of contaminants obtained from an effluent stream produced subsurface remediation. The chemicals used for the subsurface remediation are reclaimed for recycling to the remediation process. Additional reductions in contaminant bulk volume are achieved by the ultra-violet light destruction of halogenated hydrocarbons, and the complete oxidation of hydrophobic fuel hydrocarbons and hydrophilic hydrocarbons. The contaminated bulk volume will arise primarily from the disposal of the toxic metal ions. The entire process is modular, so if there are any technological breakthroughs in one or more of the component process modules, such modules can be readily replaced.

  10. Equilibrium swelling of elastomeric materials in solvent environments

    SciTech Connect

    Green, P.F.

    1990-03-01

    The equilibrium swelling of silicones, fluorosilicones, VITON and ethylene-propylene-diene (EPDM) elastomers in an environment of the jet fuel JP4 was investigated. The volume of silicone and DPDM elastomers increased by approximately 100% when they were placed in a saturated environment of JP4. Conversely, the volume of the fluorosilicone elastomer increased by approximately 15% and that of VITON less than 1%. In acetone, a commonly used solvent, the equilibrium swelling of VITON and the fluorosilicone elastomer was excessive, on the order of 100%, wheras the silicone and EPDM elastomers exhibited small changes in dimensions. Reasons for these observations are discussed in detail. We also present a simple scheme by which one may, qualitatively, determine the dimensional stability of these elastomers in different solvents if the cohesive energy density of the solvent, which is readily available in a number of handbooks, is known. We also evaluated the vulnerability of some commonly used engineering thermoplastics to JP4. The results are tabulated. 13 refs., 6 figs., 3 tab.

  11. An experimental evaluation of metallic diaphragms for positive fuel expulsion in the atmosphere explorer hydrazine propulsion subsystem

    NASA Technical Reports Server (NTRS)

    Woodruff, W. L.

    1973-01-01

    Four Arde conospheroid metallic diaphragms were tested to evaluate their capability for use in the orbit adjust propulsion subsystem (OAPS) of the Explorer spacecraft. The diaphragms will be used for positive propellant expulsion and spacecraft center of mass control. A leak-free cycle life capability of nine reversals was demonstrated. The diaphragms rolled smoothly from ring to ring in a predictable manner on the first reversal. Varying amounts of diaphragm cocking and ring skipping were observed on subsequent reversals. The diaphragm pressure differential did not exceed 7 N/sq cm during any reversal. Cycle life capability, reversal mode, and pressure differential were not affected by sudden reversals, environmental tests, or 18,000 partial reversals. An expulsion efficiency of approximately 97 percent was demonstrated. The results of these tests show that metallic diaphragms can be used as an effective means of positive fuel expulsion; however, to achieve spacecraft center of mass control, the diaphragm must not be reversed prior to flight.

  12. Optimization of a microbial fuel cell for wastewater treatment using recycled scrap metals as a cost-effective cathode material.

    PubMed

    Lefebvre, Olivier; Tan, Zi; Shen, Yujia; Ng, How Y

    2013-01-01

    Microbial fuel cell (MFC) for wastewater treatment is still hindered by the prohibitive cost of cathode material, especially when platinum is used to catalyze oxygen reduction. In this study, recycled scrap metals could be used efficiently as cathode material in a specially-designed MFC. In terms of raw power, the scrap metals ranked as follows: W/Co > Cu/Ni > Inconel 718 > carpenter alloy; however, in terms of cost and long term stability, Inconel 718 was the preferred choice. Treatment performance--assessed on real and synthetic wastewater--was considerably improved either by filling the anode compartment with carbon granules or by operating the MFC in full-loop mode. The latter option allowed reaching 99.7% acetate removal while generating a maximum power of 36 W m(-3) at an acetate concentration of 2535 mg L(-1). Under these conditions, the energy produced by the system averaged 0.1 kWh m(-3) of wastewater treated.

  13. Subconjuctival Loa loa with Calabar swelling.

    PubMed

    Cho, Hee-Yoon; Lee, Yoon-Jung; Shin, Sun-Young; Song, Hyun-Ouk; Ahn, Myoung-Hee; Ryu, Jae-Sook

    2008-08-01

    Loa loa is unique among the human filariae in that adult worms are occasionally visible during subconjunctival migration. A 29-yr-old African female student, living in Korea for the past 5 yr without ever visiting her home country, presented with acute eyelid swelling and a sensation of motion on the left eyeball. Her symptoms started one day earlier and became worse over time. Examination revealed a threadlike worm beneath the left upper bulbar conjunctiva with mild eyelid swelling as well as painless swelling of the right forearm. Upon exposure to slit-lamp illumination, a sudden movement of the worm toward the fornix was noted. After surgical extraction, parasitologic analysis confirmed the worm to be a female adult Loa loa with the vulva at the extreme anterior end. On blood smear, the microfilariae had characteristic features of Loa loa, including sheath and body nuclei up to the tip of the tail. The patient also showed eosinophilia (37%) measuring 4,100/microL. She took ivermectin (200 microg/kg) as a single dose and suffered from a mild fever and chills for one day. This patient, to the best of our knowledge, is the first case of subconjunctival loiasis with Calabar swelling in Korea. PMID:18756067

  14. Development of metal-coated ceramic anodes for molten carbonate fuel cells

    SciTech Connect

    Khandkar, A.C.; Elangovan, S.; Marianowski, L.G.

    1990-03-01

    This report documents the developmental efforts on metal coating of various ceramic substrates (LiAlO{sub 2}, SrTiO{sub 3}, and LiFeO{sub 2}) and the critical issues associated with fabricating anodes using metal-coated LiAlO{sub 2} substrates. Electroless Ni and Cu coating technology was developed to achieve complete metal coverage on LiAlO{sub 2} powder substrates. Metal coated SrTiO{sub 3} powders were fabricated into anodes by a process identical to that reported in the GE literature. Microstructural examination revealed that the grains of the ceramic had fused together, with the metal having dewetted from the surface of the ceramic. Alternate substrates that might allow for better wetting of the metal on the ceramic such as LiFeO{sub 2} and Li{sub 2}MnO{sub 3} were identified. Cu/Ni-coated (50:50 mol ratio, 50 w/o metal loading) LiFeO{sub 2} anodes were optimized to meet the MCFC anode specifications. Metal-coated gamma-LiAlO{sub 2} substrates were also developed. By using suitable chemical surface modification methods, the gamma-UAlO{sub 2} substrate surface may be modified to allow a stable metal coated anode to be fabricated. Creep testing of the metal coated ceramic anodes were conducted at IGT. It was determined that the predominant creep mechanism is due to particle rearrangement. The anode porosity, and mean pore size had significant effect on the creep of the anode. Lower porosity and pore size consistent with performance criteria are desired to reduce creep. Lower metal loading with uniformity of coverage will result in lower creep behavior of the anode. Of the two substrates evaluated, LiFeO{sub 2} in general exhibited lower creep which was attributed to superior metal adhesion.

  15. Development of metal-coated ceramic anodes for molten carbonate fuel cells. Final report

    SciTech Connect

    Khandkar, A.C.; Elangovan, S.; Marianowski, L.G.

    1990-03-01

    This report documents the developmental efforts on metal coating of various ceramic substrates (LiAlO{sub 2}, SrTiO{sub 3}, and LiFeO{sub 2}) and the critical issues associated with fabricating anodes using metal-coated LiAlO{sub 2} substrates. Electroless Ni and Cu coating technology was developed to achieve complete metal coverage on LiAlO{sub 2} powder substrates. Metal coated SrTiO{sub 3} powders were fabricated into anodes by a process identical to that reported in the GE literature. Microstructural examination revealed that the grains of the ceramic had fused together, with the metal having dewetted from the surface of the ceramic. Alternate substrates that might allow for better wetting of the metal on the ceramic such as LiFeO{sub 2} and Li{sub 2}MnO{sub 3} were identified. Cu/Ni-coated (50:50 mol ratio, 50 w/o metal loading) LiFeO{sub 2} anodes were optimized to meet the MCFC anode specifications. Metal-coated gamma-LiAlO{sub 2} substrates were also developed. By using suitable chemical surface modification methods, the gamma-UAlO{sub 2} substrate surface may be modified to allow a stable metal coated anode to be fabricated. Creep testing of the metal coated ceramic anodes were conducted at IGT. It was determined that the predominant creep mechanism is due to particle rearrangement. The anode porosity, and mean pore size had significant effect on the creep of the anode. Lower porosity and pore size consistent with performance criteria are desired to reduce creep. Lower metal loading with uniformity of coverage will result in lower creep behavior of the anode. Of the two substrates evaluated, LiFeO{sub 2} in general exhibited lower creep which was attributed to superior metal adhesion.

  16. Method of removal of heavy metal from molten salt in IFR fuel pyroprocessing

    SciTech Connect

    Gay, E.C.

    1993-12-23

    An electrochemical method of separating heavy metal values from a radioactive molten salt including Li halide at temperatures of about 500{degree}C. The method comprises positioning a solid Li-Cd alloy anode in the molten salt containing the heavy metal values, positioning a Cd-containing cathode or a solid cathode positioned above a catch crucible in the molten salt to recover the heavy metal values, establishing a voltage drop between the anode and the cathode to deposit material at the cathode to reduce the concentration of heavy metals in the salt, and controlling the deposition rate at the cathode by controlling the current between the anode and cathode.

  17. Method of removal of heavy metal from molten salt in IFR fuel pyroprocessing

    DOEpatents

    Gay, Eddie C.

    1995-01-01

    An electrochemical method of separating heavy metal values from a radioactive molten salt including Li halide at temperatures of about 500.degree. C. The method comprises positioning a solid Li--Cd alloy anode in the molten salt containing the heavy metal values, positioning a Cd-containing cathode or a solid cathode positioned above a catch crucible in the molten salt to recover the heavy metal values, establishing a voltage drop between the anode and the cathode to deposit material at the cathode to reduce the concentration of heavy metals in the salt, and controlling the deposition rate at the cathode by controlling the current between the anode and cathode.

  18. Properties of plutonium and its alloys for use as fast reactor fuels

    NASA Astrophysics Data System (ADS)

    Hecker, Siegfried S.; Stan, Marius

    2008-12-01

    Early interest in metallic plutonium fuels for fast reactors led to much research on plutonium alloy systems including binary solid solutions with the addition of aluminum, gallium, or zirconium and low melting eutectic alloys with iron and nickel or cobalt. There was also interest in ternaries of these elements with plutonium and cerium. The solid solution and eutectic alloys have most unusual properties, including negative thermal expansion in some solid-solution alloys and the highest viscosity known for liquid metals in the Pu-Fe system. Although metallic fuels have many potential advantages over ceramic fuels, the early attempts were unsuccessful because these fuels suffered from high swelling rates during burn up and high smearing densities. The liquid metal fuels experienced excessive corrosion. Subsequent work on higher melting U-Pu-Zr metallic fuels was much more promising. In light of the recent rebirth of interest in fast reactors, we review some of the key properties of the early fuels and discuss the challenges presented by the ternary alloys.

  19. Examination of the chemical composition of irradiated zirconium based fuel claddings at the metal/oxide interface by TEM

    NASA Astrophysics Data System (ADS)

    Abolhassani, S.; Bart, G.; Jakob, A.

    2010-04-01

    Detailed post-irradiation examinations have been performed at PSI on three fuel rods with differing cladding materials revealing different corrosion behaviour. The rods had been irradiated for 3-5 cycles at Gösgen nuclear power plant (pressurised water reactor), Switzerland. As zirconium corrosion is proceeding at the metal/oxide interface, extended micro-structural analyses were performed by transmission electron microscopy (TEM), expecting to possibly reveal phenomena explaining the varying corrosion resistance. This paper reports on the distribution of oxygen at the metal/oxide interface examined by energy dispersive X-ray spectroscopy (EDS) in TEM, while other micro-structural investigations have been published earlier [1]. In order to get some statistical confidence in the analyses, three neighbouring TEM samples of each cladding variant were studied. The oxygen concentration profiles of the three alloys (i.e. low-tin Zircaloy-4, Zr2.5%Nb and extra low-tin (Sn 0.56%)) both in the oxide and metal close to the metal/oxide interface are compared. The results of the examinations show the composition of the oxide in the vicinity of the interface to be sub-stoichiometric for all three materials, indicating an oxide layer adjacent to the interface, with diffusion-controlled access of oxygen to the metal/oxide interface. The metallic parts show highest oxygen concentrations at the metal/oxide interface which are reduced towards the bulk metal, pointing towards the expected second diffusion-controlled process leading to α-Zr (O). Based on the experimental results values for the diffusion coefficients in the range of 0.8-6.0 × 10 -20 m 2 s -1 are estimated for the oxygen dissolution process, the diffusion coefficient in Zircaloy-4 being six times higher than for the other two less corroding alloys. This finding is in contradiction with the present assumptions about the corrosion mechanism, and confirms the expected but not so far reported diffusion controlled

  20. Swelling induced by alpha decay in monazite and zirconolite ceramics: A XRD and TEM comparative study

    NASA Astrophysics Data System (ADS)

    Deschanels, X.; Seydoux-Guillaume, A. M.; Magnin, V.; Mesbah, A.; Tribet, M.; Moloney, M. P.; Serruys, Y.; Peuget, S.

    2014-05-01

    Zirconolite and monazite matrices are potential ceramics for the containment of actinides (Np, Cm, Am, Pu) which are produced over the reprocessing of spent nuclear fuel. Actinides decay mainly through the emission of alpha particles, which in turn causes most ceramics to undergo structural and textural changes (amorphization and/or swelling). In order to study the effects of alpha decays on the above mentioned ceramics two parallel approaches were set up. The first involved the use of an external irradiation source, Au, which allowed the deposited recoil energy to be simulated. The second was based on short-lived actinide doping with 238Pu, (i.e. an internal source), via the incorporation of plutonium oxide into both the monazite and zirconolite structures during synthesis. In both types of irradiation experiments, the zirconolite samples became amorphous at room temperature with damage close to 0.3 dpa; corresponding to a critical dose of 4 × 1018 α g-1 (i.e. ∼1.3 × 1021 keV cm-3). Both zirconolite samples also showed the same degree of macroscopic swelling at saturation (∼6%), with ballistic processes being the predominant damaging effect. In the case of the monazite however, the macroscopic swelling and amorphization were dependent on the nature of the irradiation. Externally, (Au), irradiated samples became amorphous while also demonstrating a saturation swelling of up to 8%. In contrast to this, the swelling of the 238Pu doped samples was much smaller at ∼1%. Also, unlike the externally (Au) irradiated monazite these 238Pu doped samples remained crystalline up to 7.5 × 1018 α g-1 (0.8 dpa). XRD, TEM and swelling measurements were used to fully characterize and interpret this behavior. The low swelling and the conservation of the crystalline state of 238Pu doped monazite samples indicates that alpha annealing took place within this material.

  1. A mono-dimensional nuclear fuel performance analysis code, PUMA, development from a coupled approach

    SciTech Connect

    Cheon, J. S.; Lee, B. O.; Lee, C. B.; Yacout, A. M.

    2013-07-01

    Multidimensional-multi-physical phenomena in nuclear fuels are treated as a set of mono-dimensional-coupled problems which encompass heat, displacement, fuel constituent redistribution, and fission gas release. Rather than uncoupling these coupled equations as in conventional fuel performance analysis codes, efforts are put into to obtain fully coupled solutions by relying on the recent advances of numerical analysis. Through this approach, a new SFR metal fuel performance analysis code, called PUMA (Performance of Uranium Metal fuel rod Analysis code) is under development. Although coupling between temperature and fuel constituent was made easily, the coupling between the mechanical equilibrium equation and a set of stiff kinetics equations for fission gas release is accomplished by introducing one-level Newton scheme through backward differentiation formula. Displacement equations from 1D finite element formulation of the mechanical equilibrium equation are solved simultaneously with stress equation, creep equation, swelling equation, and FGR equations. Calculations was made successfully such that the swelling and the hydrostatic pressure are interrelated each other. (authors)

  2. Fuel-cladding interaction layers in irradiated U-ZR and U-PU-ZR fuel elements.

    SciTech Connect

    Keiser, D. D.

    2006-01-23

    Argonne National Laboratory is developing an electrometallurgical treatment for spent nuclear fuels. The initial demonstration of this process is being conducted on U-Zr and U-Pu-Zr alloy fuel elements irradiated in the Experimental Breeder Reactor-II (EBR-II). The electrometallurgical treatment process extracts usable uranium from irradiated fuel elements and places residual fission products, actinides, process Zr, and cladding hulls (small segments of tubing) into two waste forms--a ceramic and a metal alloy. The metal waste form will contain the cladding hulls, Zr, and noble metal fission products, and it will be disposed of in a geologic repository. As a result, the expected composition of the waste form will need to be well understood. This report deals with the condition of the cladding, which will make up a large fraction of the metal waste form, after irradiation in EBR-II and before insertion into the electrorefiner. Specifically, it looks at layers that can be found on the inner surface of the cladding due to in-reactor interactions between the alloy fuel and the stainless steel cladding that occurs after the fuel has swelled and contacted the cladding. Many detailed examinations of fuel elements irradiated in EBR-II have been completed and are discussed in the context of interaction layer formation in irradiated cladding. The composition and thickness of the developed interaction layers are identified, along with the irradiation conditions, cladding type, and axial location on fuel elements where the thickest interaction layers can be expected to develop. It has been found that the largest interaction zones are observed at combined high power and high temperature regions of fuel elements and for fuel elements with U-Pu-Zr alloy fuel and D9 stainless steel cladding. The most prevalent, non-cladding constituent observed in the developed interaction layers are the lanthanide fission products.

  3. Combinatorial electrochemical cell array for high throughput screening of micro-fuel-cells and metal/air batteries

    NASA Astrophysics Data System (ADS)

    Jiang, Rongzhong

    2007-07-01

    An electrochemical cell array was designed that contains a common air electrode and 16 microanodes for high throughput screening of both fuel cells (based on polymer electrolyte membrane) and metal/air batteries (based on liquid electrolyte). Electrode materials can easily be coated on the anodes of the electrochemical cell array and screened by switching a graphite probe from one cell to the others. The electrochemical cell array was used to study direct methanol fuel cells (DMFCs), including high throughput screening of electrode catalysts and determination of optimum operating conditions. For screening of DMFCs, there is about 6% relative standard deviation (percentage of standard deviation versus mean value) for discharge current from 10to20mA/cm2. The electrochemical cell array was also used to study tin/air batteries. The effect of Cu content in the anode electrode on the discharge performance of the tin/air battery was investigated. The relative standard deviations for screening of metal/air battery (based on zinc/air) are 2.4%, 3.6%, and 5.1% for discharge current at 50, 100, and 150mA/cm2, respectively.

  4. Combinatorial electrochemical cell array for high throughput screening of micro-fuel-cells and metal/air batteries.

    PubMed

    Jiang, Rongzhong

    2007-07-01

    An electrochemical cell array was designed that contains a common air electrode and 16 microanodes for high throughput screening of both fuel cells (based on polymer electrolyte membrane) and metal/air batteries (based on liquid electrolyte). Electrode materials can easily be coated on the anodes of the electrochemical cell array and screened by switching a graphite probe from one cell to the others. The electrochemical cell array was used to study direct methanol fuel cells (DMFCs), including high throughput screening of electrode catalysts and determination of optimum operating conditions. For screening of DMFCs, there is about 6% relative standard deviation (percentage of standard deviation versus mean value) for discharge current from 10 to 20 mAcm(2). The electrochemical cell array was also used to study tin/air batteries. The effect of Cu content in the anode electrode on the discharge performance of the tin/air battery was investigated. The relative standard deviations for screening of metal/air battery (based on zinc/air) are 2.4%, 3.6%, and 5.1% for discharge current at 50, 100, and 150 mAcm(2), respectively. PMID:17672740

  5. Final Report - Subfreezing Start/Stop Protocol for an Advanced Metallic Open Flowfield Fuel Cell Stack

    SciTech Connect

    Conti, Amedeo

    2010-09-28

    For fuel cells to be commercially viable as powerplants in automotive applications, the ability to survive and start reliably in cold climates (as low as -40C) is a must. Since fuel cells are water-based energy systems, this requirement is a significant technical challenge. Water transport studies are imperative for achieving DOE targets for fuel cell startup time from subfreezing conditions. Stack components must be selected that endure thermal and humidity cycling over the operating range, and operating strategies must be devised that enable the fuel cell to start, i.e. generate power and heat up sufficiently before ice extinguishes the galvanic reactions, and afford evacuation of a sufficient amount of water, using a limited amount of auxiliary power, at shutdown. The objective of the CIRRUS program was to advance the state of the art in fuel cell operability under subfreezing conditions, consistent with requirements for applications involving such conditions (e.g. automotive, forklifts, backup power systems, and APUs) and DOE targets, specifically to: • Demonstrate repeatable achievement of 50% rated power in less than 30 seconds from a -20C start condition, using less than 5 MJ auxiliary energy over the complete start/stop cycle. • Demonstrate unassisted start capability from an initial temperature of -40C.

  6. Open framework metal chalcogenides as efficient photocatalysts for reduction of CO2 into renewable hydrocarbon fuel.

    PubMed

    Sasan, Koroush; Lin, Qipu; Mao, Chengyu; Feng, Pingyun

    2016-06-01

    Open framework metal chalcogenides are a family of porous semiconducting materials with diverse chemical compositions. Here we show that these materials containing covalent three-dimensional superlattices of nanosized supertetrahedral clusters can function as efficient photocatalysts for the reduction of CO2 to CH4. Unlike dense semiconductors, metal cations are successfully incorporated into the channels of the porous semiconducting materials to further tune the physical properties of the materials such as electrical conductivity and band gaps. In terms of the photocatalytic properties, the metal-incorporated porous chalcogenides demonstrated enhanced solar energy absorption and higher electrical conductivity and improved photocatalytic activity. PMID:27186825

  7. Nuclear fuel and precious-metal occurrences in Precambrian rocks of southeast Wyoming

    SciTech Connect

    Graff, P.

    1986-08-01

    Studies done on Precambrian metasediments in southeast Wyoming show the occurrence of quartz-pebble conglomerates containing subeconomic amounts of uranium and thorium. These conglomerates were marginal deposits in the late 1970s when uranium prices reached $50/lb. Fuel minerals occur in silicate phases and complicate milling operations. Because of the additional cost of processing and underground mining, no attempt to develop these resources was made. Additional studies show a favorable comparison of the rocks in Wyoming to the auriferous Witwatersrand section of South Africa. Exploration for gold in the Wyoming conglomerates has been done in a preliminary manner, but assay values to 10 ppm are reported. Both fuel minerals and gold are deposited as fossil placers by fluvial systems operating in an anoxic environment. Lag gravel and meander deposits contain heavy-mineral suites formed of coffinite, pyrite, thorite, gold, and uraninite. Available studies have not considered producing fuel and precious minerals as coproducts of surface mining methods.

  8. Gold nanorods as nanotransducers to monitor the growth and swelling of ultrathin polymer films.

    PubMed

    Tian, Limei; Fei, Max; Kattumenu, Ramesh; Abbas, Abdennour; Singamaneni, Srikanth

    2012-06-29

    In this work, we demonstrate that plasmonic nanostructures can be employed as nanoscale transducers to monitor the growth and phase transitions in ultrathin polymer films. In particular, gold nanorods with high refractive index sensitivity (~150 nm/refractive index unit (RIU)) were employed to probe the growth and swelling of polyelectrolyte multilayers (PEM). By comparing the wavelength shift and extinction intensity increase of the localized surface plasmon resonance (LSPR) of the gold nanorods coated with PEM in air and water, the swelling of PEM was estimated to be 26% ± 6%. The swelling was quantitatively confirmed with independent thickness measurement of PEM in dry and swollen states using AFM. The deployment of shape-controlled metal nanostructures with high refractive index sensitivity represents a novel and facile approach for monitoring the phase transition in polymers with nanoscale resolution.

  9. Method of removal of heavy metal from molten salt in IFR fuel pyroprocessing

    DOEpatents

    Gay, E.C.

    1995-10-03

    An electrochemical method is described for separating heavy metal values from a radioactive molten salt including Li halide at temperatures of about 500 C. The method comprises positioning a solid Li--Cd alloy anode in the molten salt containing the heavy metal values, positioning a Cd-containing cathode or a solid cathode positioned above a catch crucible in the molten salt to recover the heavy metal values, establishing a voltage drop between the anode and the cathode to deposit material at the cathode to reduce the concentration of heavy metals in the salt, and controlling the deposition rate at the cathode by controlling the current between the anode and cathode. 3 figs.

  10. Morphological effect on swelling behaviour of hydrogel

    SciTech Connect

    Yacob, Norzita; Hashim, Kamaruddin

    2014-02-12

    Hydrogels are hydrophilic polymer networks that are capable of imbibing large amounts of water. In this work, hydrogels prepared from natural and synthetic polymers were irradiated by using electron beam irradiation. The morphology of hydrogel inter-polymeric network (IPN) was investigated using Scanning Electron Microscopy (SEM). The studies reveal correlations between pore sizes of IPN with degree of cross-linking. This relation also has an effect on swelling properties of the hydrogel. The results indicated that hydrogel with smaller pore size, as a result of much dense IPN, would decrease water uptake capacity. Combination of natural and synthetic polymers to form hydrogel affects the pore size and swelling property of the hydrogel as compared to each component of polymer.

  11. Stress Singularities in Swelling Soft Solids

    NASA Astrophysics Data System (ADS)

    Goriely, Alain; Weickenmeier, Johannes; Kuhl, Ellen

    2016-09-01

    When a swelling soft solid is rigidly constrained on all sides except for a circular opening, it will bulge out to expand as observed during decompressive craniectomy, a surgical procedure used to reduce stresses in swollen brains. While the elastic energy of the solid decreases throughout this process, large stresses develop close to the opening. At the point of contact, the stresses exhibit a singularity similar to the ones found in the classic punch indentation problem. Here, we study the stresses generated by swelling and the evolution of the bulging shape associated with this process. We also consider the possibility of damage triggered by zones of either high shear stresses or high fiber stretches.

  12. Morphological effect on swelling behaviour of hydrogel

    NASA Astrophysics Data System (ADS)

    Yacob, Norzita; Hashim, Kamaruddin

    2014-02-01

    Hydrogels are hydrophilic polymer networks that are capable of imbibing large amounts of water. In this work, hydrogels prepared from natural and synthetic polymers were irradiated by using electron beam irradiation. The morphology of hydrogel inter-polymeric network (IPN) was investigated using Scanning Electron Microscopy (SEM). The studies reveal correlations between pore sizes of IPN with degree of cross-linking. This relation also has an effect on swelling properties of the hydrogel. The results indicated that hydrogel with smaller pore size, as a result of much dense IPN, would decrease water uptake capacity. Combination of natural and synthetic polymers to form hydrogel affects the pore size and swelling property of the hydrogel as compared to each component of polymer.

  13. A study of metal distribution from lignite fuels using trees as biological monitors.

    PubMed

    Sawidis, T; Chettri, M K; Papaioannou, A; Zachariadis, G; Stratis, J

    2001-01-01

    Concentrations of five metals (Cd, Cu, Mn, Fe, Zn) were determined in tree leaves collected from an area with large coal-fired plants in Ptolemais, Macedonia, Greece. The analyses were carried out with flame atomic absorption spectroscopy. Mean heavy metal content in the tree leaves is, in descending order, Fe>Mn>Zn>Cu>Cd. In Populus nigra and Salix babylonica the dense piled leaves and the widespread root system are the reasons for high heavy metal uptake. Conifer trees Pinus nigra and Juniperus arizona, which have a rough leaf surface, also had elevated concentrations. Leaves with a smooth surface were less contaminated. The presence of one metal within leaf cells may reduce the uptake or toxicity of other metals. Fruits accumulated less heavy metal than the corresponding leaves. The most damaged areas are those in the direct vicinity of the coal power plants, and the rate of damage caused in the environment is affected by the main wind direction. All sampling sites in Ptolemais basin are generally more or less polluted when compared with the control site.

  14. Open framework metal chalcogenides as efficient photocatalysts for reduction of CO2 into renewable hydrocarbon fuel

    NASA Astrophysics Data System (ADS)

    Sasan, Koroush; Lin, Qipu; Mao, Chengyu; Feng, Pingyun

    2016-05-01

    Open framework metal chalcogenides are a family of porous semiconducting materials with diverse chemical compositions. Here we show that these materials containing covalent three-dimensional superlattices of nanosized supertetrahedral clusters can function as efficient photocatalysts for the reduction of CO2 to CH4. Unlike dense semiconductors, metal cations are successfully incorporated into the channels of the porous semiconducting materials to further tune the physical properties of the materials such as electrical conductivity and band gaps. In terms of the photocatalytic properties, the metal-incorporated porous chalcogenides demonstrated enhanced solar energy absorption and higher electrical conductivity and improved photocatalytic activity.Open framework metal chalcogenides are a family of porous semiconducting materials with diverse chemical compositions. Here we show that these materials containing covalent three-dimensional superlattices of nanosized supertetrahedral clusters can function as efficient photocatalysts for the reduction of CO2 to CH4. Unlike dense semiconductors, metal cations are successfully incorporated into the channels of the porous semiconducting materials to further tune the physical properties of the materials such as electrical conductivity and band gaps. In terms of the photocatalytic properties, the metal-incorporated porous chalcogenides demonstrated enhanced solar energy absorption and higher electrical conductivity and improved photocatalytic activity. Electronic supplementary information (ESI) available: The synthetic procedure, facilities information, EDX patterns and UV-Vis data. See DOI: 10.1039/c6nr02525k

  15. Measurement of thermal diffusivity of depleted uranium metal microspheres

    NASA Astrophysics Data System (ADS)

    Humrickhouse-Helmreich, Carissa J.; Corbin, Rob; McDeavitt, Sean M.

    2014-03-01

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time-temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal.

  16. Molecular accessibility in solvent swelled coals

    SciTech Connect

    Kispert, L.D.

    1993-02-01

    An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a non swelling solvent to eliminate any spin probes that are not trapped in the pores and the spin concentration is measured. Comparing these spin probe measurements to DRIFT data have shown that the relative number distribution of acidic functionalities can be accurately predicted by the spin probe method. The spin probe method had also been used to predict the increase in elongated voids in Pittsburgh No. 8 (APCS No. 4) upon swelling with pyridine in agreement with independent SANS data. NMR relaxation data show that it is possible to deduce the pore (accessibility) distribution as a function of size (up to 6 mn). It has also been possible by variable temperature and ENDOR measurements to determine the presence of hydrogen bonding as a function of pore shape and size. The advantage of the EPR method is that it permits molecules of selected shape and size to be used as probes of accessible regions of coal, thus providing information on the importance of molecular shape.

  17. Evolution of midplate hotspot swells: Numerical solutions

    NASA Technical Reports Server (NTRS)

    Liu, Mian; Chase, Clement G.

    1990-01-01

    The evolution of midplate hotspot swells on an oceanic plate moving over a hot, upwelling mantle plume is numerically simulated. The plume supplies a Gaussian-shaped thermal perturbation and thermally-induced dynamic support. The lithosphere is treated as a thermal boundary layer with a strongly temperature-dependent viscosity. The two fundamental mechanisms of transferring heat, conduction and convection, during the interaction of the lithosphere with the mantle plume are considered. The transient heat transfer equations, with boundary conditions varying in both time and space, are solved in cylindrical coordinates using the finite difference ADI (alternating direction implicit) method on a 100 x 100 grid. The topography, geoid anomaly, and heat flow anomaly of the Hawaiian swell and the Bermuda rise are used to constrain the models. Results confirm the conclusion of previous works that the Hawaiian swell can not be explained by conductive heating alone, even if extremely high thermal perturbation is allowed. On the other hand, the model of convective thinning predicts successfully the topography, geoid anomaly, and the heat flow anomaly around the Hawaiian islands, as well as the changes in the topography and anomalous heat flow along the Hawaiian volcanic chain.

  18. Alkali activation of recovered fuel-biofuel fly ash from fluidised-bed combustion: Stabilisation/solidification of heavy metals.

    PubMed

    Yliniemi, Juho; Pesonen, Janne; Tiainen, Minna; Illikainen, Mirja

    2015-09-01

    Recovered fuel-biofuel fly ash from a fluidized bed boiler was alkali-activated and granulated with a sodium-silicate solution in order to immobilise the heavy metals it contains. The effect of blast-furnace slag and metakaolin as co-binders were studied. Leaching standard EN 12457-3 was applied to evaluate the immobilisation potential. The results showed that Ba, Pb and Zn were effectively immobilised. However, there was increased leaching after alkali activation for As, Cu, Mo, Sb and V. The co-binders had minimal or even negative effect on the immobilisation. One exception was found for Cr, in which the slag decreased leaching, and one was found for Cu, in which the slag increased leaching. A sequential leaching procedure was utilized to gain a deeper understanding of the immobilisation mechanism. By using a sequential leaching procedure it is possible fractionate elements into watersoluble, acid-soluble, easily-reduced and oxidisable fractions, yielding a total 'bioavailable' amount that is potentially hazardous for the environment. It was found that the total bioavailable amount was lower following alkali activation for all heavy metals, although the water-soluble fraction was higher for some metals. Evidence from leaching tests suggests the immobilisation mechanism was chemical retention, or trapping inside the alkali activation reaction products, rather than physical retention, adsorption or precipitation as hydroxides. PMID:26054963

  19. Laminated exfoliated graphite composite-metal compositions for fuel cell flow field plate or bipolar plate applications

    DOEpatents

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2014-05-20

    An electrically conductive laminate composition for fuel cell flow field plate or bipolar plate applications. The laminate composition comprises at least a thin metal sheet having two opposed exterior surfaces and a first exfoliated graphite composite sheet bonded to the first of the two exterior surfaces of the metal sheet wherein the exfoliated graphite composite sheet comprises: (a) expanded or exfoliated graphite and (b) a binder or matrix material to bond the expanded graphite for forming a cohered sheet, wherein the binder or matrix material is between 3% and 60% by weight based on the total weight of the first exfoliated graphite composite sheet. Preferably, the first exfoliated graphite composite sheet further comprises particles of non-expandable graphite or carbon in the amount of between 3% and 60% by weight based on the total weight of the non-expandable particles and the expanded graphite. Further preferably, the laminate comprises a second exfoliated graphite composite sheet bonded to the second surface of the metal sheet to form a three-layer laminate. Surface flow channels and other desired geometric features can be built onto the exterior surfaces of the laminate to form a flow field plate or bipolar plate. The resulting laminate has an exceptionally high thickness-direction conductivity and excellent resistance to gas permeation.

  20. Development and performance analysis of a metallic micro-direct methanol fuel cell for high-performance applications

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Zhang, Yufeng; He, Hong; Li, Jianmin; Yuan, Zhenyu; Na, Chaoran; Liu, Xiaowei

    As a promising candidate for conventional micro-power sources, the micro-direct methanol fuel cell (μDMFC) is currently attracting increased attention due to its various advantages and prospective suitability for portable applications. This paper reports the design, fabrication and analysis of a high-performance μDMFC with two metal current collectors. Employing micro-stamping technology, the current collectors are fabricated on 300-μm-thick stainless steel plates. The flow fields for both cathode and anode are uniform in shape and size. Two sheets of stainless steel mesh are added between the membrane electrode assembly (MEA) and current collectors in order to improve cell performance. To avoid electrochemical corrosion, titanium nitride (TiN) layers with thickness of 500 nm are deposited onto the surface of current collectors and stainless steel mesh. The performance of this metallic μDMFC is thoroughly studied by both simulation and experimental methods. The results show that all the parameters investigated, including current collector material, stainless steel mesh, anode feeding mode, methanol concentration, anode flow rate, and operating temperature have significant effects on cell performance. Moreover, the results show that under optimal operating conditions, the metallic μDMFC exhibits promising performance, yielding a maximum power density of 65.66 mW cm -2 at 40 °C and 115.0 mW cm -2 at 80 °C.

  1. Design Principles for Metal Oxide Redox Materials for Solar-Driven Isothermal Fuel Production

    PubMed Central

    Michalsky, Ronald; Botu, Venkatesh; Hargus, Cory M; Peterson, Andrew A; Steinfeld, Aldo

    2015-01-01

    The performance of metal oxides as redox materials is limited by their oxygen conductivity and thermochemical stability. Predicting these properties from the electronic structure can support the screening of advanced metal oxides and accelerate their development for clean energy applications. Specifically, reducible metal oxide catalysts and potential redox materials for the solar-thermochemical splitting of CO2 and H2O via an isothermal redox cycle are examined. A volcano-type correlation is developed from available experimental data and density functional theory. It is found that the energy of the oxygen-vacancy formation at the most stable surfaces of TiO2, Ti2O3, Cu2O, ZnO, ZrO2, MoO3, Ag2O, CeO2, yttria-stabilized zirconia, and three perovskites scales with the Gibbs free energy of formation of the bulk oxides. Analogously, the experimental oxygen self-diffusion constants correlate with the transition-state energy of oxygen conduction. A simple descriptor is derived for rapid screening of oxygen-diffusion trends across a large set of metal oxide compositions. These general trends are rationalized with the electronic charge localized at the lattice oxygen and can be utilized to predict the surface activity, the free energy of complex bulk metal oxides, and their oxygen conductivity. PMID:26855639

  2. Thermal Analysis of Surrogate Simulated Molten Salts with Metal Chloride Impurities for Electrorefining Used Nuclear Fuel

    SciTech Connect

    Toni Y. Gutknecht; Guy L. Fredrickson; Vivek Utgikar

    2012-04-01

    This project is a fundamental study to measure thermal properties (liquidus, solidus, phase transformation, and enthalpy) of molten salt systems of interest to electrorefining operations, which are used in both the fuel cycle research & development mission and the spent fuel treatment mission of the Department of Energy. During electrorefining operations the electrolyte accumulates elements more active than uranium (transuranics, fission products and bond sodium). The accumulation needs to be closely monitored because the thermal properties of the electrolyte will change as the concentration of the impurities increases. During electrorefining (processing techniques used at the Idaho National Laboratory to separate uranium from spent nuclear fuel) it is important for the electrolyte to remain in a homogeneous liquid phase for operational safeguard and criticality reasons. The phase stability of molten salts in an electrorefiner may be adversely affected by the buildup of fission products in the electrolyte. Potential situations that need to be avoided are: (i) build up of fissile elements in the salt approaching the criticality limits specified for the vessel (ii) freezing of the salts due to change in the liquidus temperature and (iii) phase separation (non-homogenous solution) of elements. The stability (and homogeneity) of the phases can potentially be monitored through the thermal characterization of the salts, which can be a function of impurity concentration. This work describes the experimental results of typical salts compositions, consisting of chlorides of strontium, samarium, praseodymium, lanthanum, barium, cerium, cesium, neodymium, sodium and gadolinium (as a surrogate for both uranium and plutonium), used in the processing of used nuclear fuels. Differential scanning calorimetry was used to analyze numerous salt samples providing results on the thermal properties. The property of most interest to pyroprocessing is the liquidus temperature. It was

  3. A New Process for Hot Metal Production at Low Fuel Rate - Phase 1 Feasibility Study

    SciTech Connect

    Dr. Wei-Kao Lu

    2006-02-01

    The project is part of the continuing effort by the North American steel industry to develop a coal-based, cokeless process for hot metal production. The objective of Phase 1 is to determine the feasibility of designing and constructing a pilot scale facility with the capacity of 42,000 mtpy of direct reduced iron (DRI) with 95% metallization. The primary effort is performed by Bricmont, Inc., an international engineering firm, under the supervision of McMaster University. The study focused on the Paired Straight Hearth furnace concept developed previously by McMaster University, The American Iron and Steel Institute and the US Department of Energy.

  4. Failed fuel monitoring and surveillance techniques for liquid metal cooled fast reactors

    SciTech Connect

    Lambert, J.D.B.; Mikaili, R.; Gross, K.C.; Strain, R.V.; Aoyama, T.; Ukai, S.; Nomura, S.; Nakae, N.

    1995-05-01

    The Experimental Breeder Reactor II (EBR-II) has been used as a facility for irradiation of LMR fuels and components for thirty years. During this time many tests of experimental fuel were continued to cladding breach in order to study modes of element failure; the methods used to identify such failures are described in a parallel paper. This paper summarizes experience of monitoring the delayed-neutron (DN) and fission-gas (FG) release behavior of a smaller number of elements that continued operation in the run-beyond-cladding-breach (RBCB) mode. The scope of RBCB testing, the methods developed to characterize failures on-line, and examples of DN/FG behavior are described.

  5. Nitrogen oxides reduction by carbonaceous materials and carbon dioxide separation using regenerative metal oxides from fossil fuel based flue gas

    NASA Astrophysics Data System (ADS)

    Gupta, Himanshu

    The ever-growing energy demands due to rising global population and continuing lifestyle improvements has placed indispensable emphasis on fossil fuels. Combustion of fossil fuels leads to the emission of harmful gaseous pollutants such as oxides of sulfur (SOx) and nitrogen (NOx), carbon dioxide (CO2), mercury, particulate matter, etc. Documented evidence has proved that this air pollution leads to adverse environmental health. This dissertation focuses on the development of technologies for the control of NOx and CO2 emissions. The first part of the thesis (Chapters 2--6) deals with the development of carbon based post combustion NOx reduction technology called CARBONOX process. High temperature combustion oxidizes both atmospheric nitrogen and organic nitrogen in coal to nitric oxide (NO). The reaction rate between graphite and NO is slow and requires high temperature (>900°C). The presence of metallic species in coal char catalyzes the reaction. The reaction temperature is lowered in the presence of oxygen to about 600--850°C. Chemical impregnation, specifically sodium compounds, further lowers the reaction temperature to 350--600°C. Activated high sodium lignite char (HSLC) provided the best performance for NO reduction. The requirement of char for NOx reduction is about 8--12 g carbon/g NO reduced in the presence of 2% oxygen in the inlet gas. The second part of this dissertation (chapter 7--8) focuses on the development of a reaction-based process for the separation of CO2 from combustion flue gas. Certain metal oxides react with CO2 forming metal carbonates under flue gas conditions. They can be calcined separately to yield CO2. Calcium oxide (CaO) has been identified as a viable metal oxide for the carbonation-calcination reaction (CCR) scheme. CaO synthesized from naturally occurring precursors (limestone and dolomite) attained 45--55% of their stoichiometric conversion due to the susceptibility of their microporous structure. High surface area

  6. Performance Comparison of Metallic, Actinide Burning Fuel in Lead-Bismuth and Sodium Cooled Fast Reactors

    SciTech Connect

    Weaver, Kevan Dean; Herring, James Stephen; Mac Donald, Philip Elsworth

    2001-04-01

    Various methods have been proposed to “incinerate” or “transmutate” the current inventory of trans-uranic waste (TRU) that exits in spent light-water-reactor (LWR) fuel, and weapons plutonium. These methods include both critical (e.g., fast reactors) and non-critical (e.g., accelerator transmutation) systems. The work discussed here is part of a larger effort at the Idaho National Engineering and Environmental Laboratory (INEEL) and at the Massachusetts Institute of Technology (MIT) to investigate the suitability of lead and lead-alloy cooled fast reactors for producing low-cost electricity as well as for actinide burning. The neutronics of non-fertile fuel loaded with 20 or 30-wt% light water reactor (LWR) plutonium plus minor actinides for use in a lead-bismuth cooled fast reactor are discussed in this paper, with an emphasis on the fuel cycle life and isotopic content. Calculations show that the average actinide burn rate is similar for both the sodium and lead-bismuth cooled cases ranging from -1.02 to -1.16 g/MWd, compared to a typical LWR actinide generation rate of 0.303 g/MWd. However, when using the same parameters, the sodium-cooled case went subcritical after 0.2 to 0.8 effective full power years, and the lead-bismuth cooled case ranged from 1.5 to 4.5 effective full power years.

  7. Magnetic resonance imaging of clays: swelling, sedimentation, dissolution

    NASA Astrophysics Data System (ADS)

    Dvinskikh, Sergey; Furo, Istvan

    2010-05-01

    measure of clay distribution in extended samples during different physical processes such as swelling, dissolution, and sedimentation on the time scale from minutes to years [1-3]. To characterize the state of colloids that form after/during clay swelling the water self-diffusion coefficient was measured on a spatially resolved manner. Both natural clays and purified and ion-exchanged montmorillonite clays were investigated. The primary variables were clay composition and water ionic strength. These results have a significant impact for engineering barriers for storage of spent nuclear fuel where clay erosion by low salinity water must be addressed. Presented methods were developed under the motivation of using bentonite clays as a buffer medium to build in-ground barriers for the encapsulation of radioactive waste. Nevertheless, the same approaches can be found suitable in other applications in soil and environmental science to study other types of materials as they swell, dissolve, erode, or sediment. Acknowledgements: This work has been supported by the Swedish Nuclear Fuel and Waste Management Co (SKB) and the Swedish Research Council VR. [1] N. Nestle, T. Baumann, R. Niessner, Magnetic resonance imaging in environmental science. Environ. Sci. Techn. 36 154A (2002). [2] S. V. Dvinskikh, K. Szutkowski, I. Furó. MRI profiles over a very wide concentration ranges: application to swelling of a bentonite clay. J. Magn. Reson. 198 146 (2009). [3] S. V. Dvinskikh, I. Furó. Magnetic resonance imaging and nuclear magnetic resonance investigations of bentonite systems. Technical Report, TR-09-27, SKB (2009), www.skb.se.

  8. Quantitative analyses of extrudate swell for polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Wang, Kejian; Sun, Chongxiao

    2009-07-01

    The quantitative theory of extrudate swell for nanocomposite and pure polymer is significant either for optimum processing or for understanding their viscoelasticity. Based on Song's die swell theory for entangled polymers, one extrudate swell correlation with material properties and capillary parameters was developed for polymer melt and their nanocomposites when compensating reservoir entry effect. It was the first to find that the composite swell ratio can be the matrix swell ratio multiplied by the concentration shift factor. The factor is the functions of the shear field, filler content, filler internal structure and the surface state as well as the matrix properties. The quantitative model was well fitful for the five kinds of nanoomposites.

  9. Mineralogy-swelling potential relationships for expansive shales

    USGS Publications Warehouse

    Olsen, H.W.; Krosley, L.; Nelson, K.; Chabrillat, S.; Goetz, A.F.H.; Noe, D.C.

    2000-01-01

    The extent to which mineralogy and swelling potential is correlated in the expansive clays and shales is studied. Sites are selected in Cretaceous shales, including Pierre Shale, that are uplifted into steeply dipping strata near the foothills of the Rocky Mountains. Swelling potentials are obtained on limited suites of samples with conventional and labor-intensive schemes including Seed and Chen's schemes, and with swell-consolidation measurements in response to saturation, consolidation, and rebound in an oedometer. The results showing the percent total smectite provide a useful index of swelling potential concept defined by Seed and correlates well with the swelling potential indices developed by Seed, Chen, and McKeen.

  10. Synthesis and characterization of new ternary transition metal sulfide anodes for H 2S-powered solid oxide fuel cell

    NASA Astrophysics Data System (ADS)

    Vorontsov, V.; Luo, J. L.; Sanger, A. R.; Chuang, K. T.

    A number of ternary transition metal sulfides with general composition AB 2S 4 (where A and B are different transition metal atoms) have been prepared and investigated as potential anode catalysts for use in H 2S-powered solid oxide fuel cells (SOFCs). For the initial screening, polarization resistance of the materials was measured in a two electrode symmetrical cell at 700-850 °C. Vanadium-based materials showed the lowest polarization resistance, and so were chosen for subsequent full cell tests using the configuration [H 2S, AV 2S 4/YSZ/Pt, air] (where A = Ni, Cr, Mo). MoV 2S 4 anode had superior activity and performance in the full cell setup, consistent with results from symmetrical cell tests. Polarization curves showed MoV 2S 4 had the lowest potential drop, with up to a 200 mA cm -2 current density at 800 °C. The highest power density of ca. 275 mW cm -2 at 800 °C was obtained with a pure H 2S stream. Polarization resistance of materials was a strong function of current density, and showed a sharp change of slope attributable to a change in the rate-limiting step of the anode reaction mechanism. MoV 2S 4 was chemically stable during prolonged (10 days) exposure to H 2S at 850 °C, and fuel cell performance was stable during continuous 3-day operation at 370 mA cm -2 current density.

  11. Efficient solar-driven synthesis, carbon capture, and desalinization, STEP: solar thermal electrochemical production of fuels, metals, bleach.

    PubMed

    Licht, S

    2011-12-15

    STEP (solar thermal electrochemical production) theory is derived and experimentally verified for the electrosynthesis of energetic molecules at solar energy efficiency greater than any photovoltaic conversion efficiency. In STEP the efficient formation of metals, fuels, chlorine, and carbon capture is driven by solar thermal heated endothermic electrolyses of concentrated reactants occuring at a voltage below that of the room temperature energy stored in the products. One example is CO(2) , which is reduced to either fuels or storable carbon at a solar efficiency of over 50% due to a synergy of efficient solar thermal absorption and electrochemical conversion at high temperature and reactant concentration. CO(2) -free production of iron by STEP, from iron ore, occurs via Fe(III) in molten carbonate. Water is efficiently split to hydrogen by molten hydroxide electrolysis, and chlorine, sodium, and magnesium from molten chlorides. A pathway is provided for the STEP decrease of atmospheric carbon dioxide levels to pre-industial age levels in 10 years. PMID:22025216

  12. Reducing the deactivation of Ni-metal during the catalytic partial oxidation of a surrogate diesel fuel mixture

    SciTech Connect

    Haynes, Daniel J.; Campos, Andrew; Smith, Mark W.; Berry, David A.; Shekhawat, Dushyant; Spivey, James J.

    2010-09-01

    Ni catalysts are active and selective for the conversion of hydrocarbon into synthesis gas. However, conventional supported Ni catalysts rapidly deactivate at the high temperatures required for partial oxidation of diesel fuel by sintering and metal vaporization, as well as by carbon deposition and sulfur poisoning. Thus, to reduce deactivation Ni (3 wt%) was substituted into the structures of Ba-hexaaluminate (BNHA) and La–Sr–Zr pyrochlore (LSZN), and their activity was compared to a supported Ni/Al2O3 for the catalytic partial oxidation (CPOX) of a surrogate diesel fuel. Characterization by XRD showed a single phase -alumina for the hexaaluminate, while LSZN had a pyrochlore structure with a defect SrZrO3 perovskite phase. Temperature programmed reduction experiments confirmed Ni was reducible in all catalysts. XANES results confirmed that Ni atoms were substituted into the hexaaluminate and pyrochlore structures, as spectra for each catalyst showed different coordination environments for Ni compared to a NiO standard. During CPOX activity tests (T = 900°C and WHSV= 50,000 scc/gcat/h), the LSZN pyrochlore produced stable H2 and CO yields in the presence of 5 wt% 1-methylnaphthalene and 50ppmw dibenzothiophene/n-tetradecane for 2 h, while both Ni/Al2O3 and BNHA catalysts were irreversibly deactivated by this mixture over the same time. Activity loss was strongly linked to carbon formation

  13. Surface science and electrochemical studies of metal-modified carbides for fuel cells and hydrogen production

    NASA Astrophysics Data System (ADS)

    Kelly, Thomas Glenn

    Carbides of the early transition metals have emerged as low-cost catalysts that are active for a wide range of reactions. The surface chemistry of carbides can be altered by modifying the surface with small amounts of admetals. These metal-modified carbides can be effective replacements for Pt-based bimetallic systems, which suffer from the drawbacks of high cost and low thermal stability. In this dissertation, metal-modified carbides were studied for reactions with applications to renewable energy technologies. It is demonstrated that metal-modified carbides possess high activity for alcohol reforming and electrochemical hydrogen production. First, the surface chemistry of carbides towards alcohol decomposition is studied using density functional theory (DFT) and surface science experiments. The Vienna Ab initio Simulation Package (VASP) was used to calculate the binding energies of alcohols and decomposition intermediates on metal-modified carbides. The calculated binding energies were then correlated to reforming activity determined experimentally using temperature programmed desorption (TPD). In the case of methanol decomposition, it was found that tungsten monocarbide (WC) selectively cleaved the C-O bond to produce methane. Upon modifying the surface with a single layer of metal such as Ni, Pt, or Rh, the selectivity shifted towards scission of the C-H bonds while leaving the C-O bond intact, producing carbon monoxide (CO) and H2. High resolution energy loss spectroscopy (HREELS) was used to examine the bond breaking sequence as a function of temperature. From HREELS, it was shown that the surfaces followed an activity trend of Rh > Ni > Pt. The Au-modified WC surface possessed too low of a methanol binding energy, and molecular desorption of methanol was the most favorable pathway on this surface. Next, the ability of Rh-modified WC to break the C-C bond of C2 and C3 alcohols was demonstrated. HREELS showed that ethanol decomposed through an acetaldehyde

  14. Swelling transition of a clay induced by heating.

    PubMed

    Hansen, E L; Hemmen, H; Fonseca, D M; Coutant, C; Knudsen, K D; Plivelic, T S; Bonn, D; Fossum, J O

    2012-01-01

    Clays are of paramount importance for soil stability, but also in applications ranging from oil recovery to composites and hydrogels. Generically, clays are divided into two subclasses: macroscopically swelling, 'active' clays that have the capacity for taking up large amounts of water to form stable gels, and 'passive' or non-swelling clays; the former stabilize soils whereas the latter are known to lead to landslides. However, it has been unclear so far what mechanisms underlie clay swelling. Here, we report the first observation of a temperature-induced transition from a passive to an active, swelling clay. We propose a simple description of the swelling transition; while net attractive interactions are dominant at low temperatures so that the clay particles remain attached to each other in stacks, at higher temperatures it is energetically favourable for the clay to swell due to the entropy that is gained by counterions which are liberated during swelling.

  15. Swelling transition of a clay induced by heating.

    PubMed

    Hansen, E L; Hemmen, H; Fonseca, D M; Coutant, C; Knudsen, K D; Plivelic, T S; Bonn, D; Fossum, J O

    2012-01-01

    Clays are of paramount importance for soil stability, but also in applications ranging from oil recovery to composites and hydrogels. Generically, clays are divided into two subclasses: macroscopically swelling, 'active' clays that have the capacity for taking up large amounts of water to form stable gels, and 'passive' or non-swelling clays; the former stabilize soils whereas the latter are known to lead to landslides. However, it has been unclear so far what mechanisms underlie clay swelling. Here, we report the first observation of a temperature-induced transition from a passive to an active, swelling clay. We propose a simple description of the swelling transition; while net attractive interactions are dominant at low temperatures so that the clay particles remain attached to each other in stacks, at higher temperatures it is energetically favourable for the clay to swell due to the entropy that is gained by counterions which are liberated during swelling. PMID:22943004

  16. Metallic inert matrix fuel concept for minor actinides incineration to achieve ultra-high burn-up

    NASA Astrophysics Data System (ADS)

    Lipkina, K.; Savchenko, A.; Skupov, M.; Glushenkov, A.; Vatulin, A.; Uferov, O.; Ivanov, Y.; Kulakov, G.; Ershov, S.; Maranchak, S.; Kozlov, A.; Maynikov, E.; Konova, K.

    2014-09-01

    The advantages of using Inert Matrix Fuel (IMF) in a design of an isolated arrangement of fuel are considered, with emphasis on, low temperatures in the fuel center, achievement of high burn-ups, and an environment friendly process for the fuel element fabrication. Changes in the currently existing concept of IMF usage are suggested, involving novel IMF design in the nuclear fuel cycle.

  17. Application of Neutron-Absorbing Structural-Amorphous Metal (SAM) Coatings for Spent Nuclear Fuel (SNF) Container to Enhance Criticality Safety Control

    SciTech Connect

    Choi, J

    2007-01-12

    This report describes the analysis and modeling approaches used in the evaluation for criticality-control applications of the neutron-absorbing structural-amorphous metal (SAM) coatings. The applications of boron-containing high-performance corrosion-resistant material (HPCRM)--amorphous metal as the neutron-absorbing coatings to the metallic support structure can enhance criticality safety controls for spent nuclear fuel in baskets inside storage containers, transportation casks, and disposal containers. The use of these advanced iron-based, corrosion-resistant materials to prevent nuclear criticality in transportation, aging, and disposal containers would be extremely beneficial to the nuclear waste management programs.

  18. One-pot synthesis of high-performance Co/graphene electrocatalysts for glucose fuel cells free of enzymes and precious metals.

    PubMed

    Ci, Suqin; Wen, Zhenhai; Mao, Shun; Hou, Yang; Cui, Shumao; He, Zhen; Chen, Junhong

    2015-06-01

    A facile recipe has been developed to prepare three-dimensional nanoarchitectures of nitrogen-doped graphene loading Co nanoparticle hybrids (Co/NG). The hybrids show an outstanding electrocatalytic activity for glucose oxidation reaction (GOR) and oxygen reduction reaction (ORR), and thus can be used as electrode materials of a nonenzymatic and precious-metal-free glucose fuel cell (GFC). PMID:25960100

  19. An experimental evaluation of metallic diaphragms for positive fuel expulsion in the Atmosphere Explorer, hydrazine propulsion subsystem

    NASA Technical Reports Server (NTRS)

    Woodruff, W. L.

    1973-01-01

    Four Arde conospheroid metallic diaphragms were tested at NASA to evaluate their capability for use in the orbit adjust propulsion subsystem (OAPS) of the Atmosphere Explorer spacecraft (AE's C, D, and E). The diaphragms will be used for positive propellant expulsion and spacecraft center of mass (c.m.) control. A leak-free cycle life capability of nine reversals was demonstrated. The diaphragms rolled smoothly from ring to ring in a predictable manner on the first reversal. Varying amounts of diaphragm cocking and ring skipping were observed on subsequent reversals. The diaphragm pressure differential did not exceed 10 psid during any reversal. Cycle life capability, reversal mode, and pressure differential were not affected by sudden reversals, environmental tests, or 18,000 partial reversals. An expulsion efficiency of approximately 97 percent was demonstrated. The results of these tests show that metallic diaphragms can be used as an effective means of positive fuel expulsion; however, to achieve spacecraft c.m. control, the diaphragm must not be reversed prior to flight.

  20. Creep rupture of the joint of a solid oxide fuel cell glass-ceramic sealant with metallic interconnect

    NASA Astrophysics Data System (ADS)

    Lin, Chih-Kuang; Lin, Kun-Liang; Yeh, Jing-Hong; Wu, Si-Han; Lee, Ruey-Yi

    2014-01-01

    Creep properties of sandwich joint specimens made of a newly developed BaO-B2O3-Al2O3-SiO2 glass-ceramic sealant (GC-9) and a ferritic-stainless-steel interconnect (Crofer 22 H) for planar solid oxide fuel cells (pSOFCs) are investigated at 800 °C under constant shear and tensile loadings. The creep rupture time of Crofer 22 H/GC-9/Crofer 22 H joint specimens is increased with a decrease in applied load for both shear and tensile loading modes. The given metal/sealant/metal joint has a greater degradation of joint strength at 800 °C under prolonged, constant tensile loading as compared to shear loading. The tensile creep strength at a rupture time of 1000 h is about 9% of the average tensile joint strength, while the shear creep strength at 1000 h is about 23% of the average shear joint strength. Failure patterns of both shear and tensile joint specimens are similar regardless of the creep rupture time. In general, creep cracks initiate at the interface between the (Cr,Mn)3O4 spinel layer and the BaCrO4 chromate layer, penetrate through the BaCrO4 layer, and propagate along the interface between the chromate layer and glass-ceramic substrate until final fracture. Final, fast fracture occasionally takes place within the glass-ceramic layer.

  1. Characteristics of electricity production by metallic and nonmetallic anodes immersed in mud sediment using sediment microbial fuel cell

    NASA Astrophysics Data System (ADS)

    Haque, N.; Cho, D.; Kwon, S.

    2015-09-01

    Sediment microbial fuel cell (SMFC), equipped with Zn, Al, Cu, Fe or graphite felt (GF) anode and marine sediment, was performed. Graphite felt was used as a common cathode. SMFC was single chambered and did not use any redox mediator. The aim of this work was to find efficient anodic material. Oxidation reduction potential (ORP), cell voltage, current density, power density, pH and chemical oxygen demand (COD) were measured for SMFC's performance. The order of maximum power density was 913 mWm-2 for Zn, 646 mWm-2 for Fe, 387.8 mWm-2 for Cu, 266 mWm-2 for Al, and 127 mWm-2 for GF. The current density over voltage was found to be strongly correlated one another in most metal electrodes but the graphite felt electrode, in which relatively weaker electricity was observed because of its biooriented mechanism. Metal corrosion reactions and/or a complicated microbial electron transfer mechanism acting around the anodic compartment may facilitate to generate electricity. We presume that more sophisticated selection of anodic material can lead to better performance in SMFC.

  2. Characteristics of electricity production by metallic and nonmetallic anodes immersed in mud sediment using sediment microbial fuel cell

    NASA Astrophysics Data System (ADS)

    Haque, N.; Cho, D.; Kwon, S.

    2015-09-01

    Sediment microbial fuel cell (SMFC), equipped with Zn, Al, Cu, Fe orgraphite felt (GF) anodeand marine sediment, was performed. Graphite felt was used as a common cathode. SMFC was single chambered and did not use any redox mediator. The aimof this workwas to find efficient anodic material. Oxidation reduction potential (ORP), cell voltage, current density, power density, pH and chemical oxygen demand (COD) were measured for SMFC's performance.The order of maximum power density was 913 mWm-2 for Zn, 646 mWm-2 for Fe, 387.8 mWm-2 for Cu, 266 mWm-2 for Al, and 127 mWm-2 for GF. The current density over voltage was found to be strongly correlated one another in most metal electrodesbutthe graphite felt electrode, in which relatively weaker electricity was observed because of its bio-oriented mechanism. Metal corrosion reactionsand/or a complicated microbial electron transfer mechanismacting around the anodiccompartment may facilitate to generate electricity. We presume that more sophisticated selection of anodic material can lead to better performance in SMFC.

  3. Optimization of a microbial fuel cell for wastewater treatment using recycled scrap metals as a cost-effective cathode material.

    PubMed

    Lefebvre, Olivier; Tan, Zi; Shen, Yujia; Ng, How Y

    2013-01-01

    Microbial fuel cell (MFC) for wastewater treatment is still hindered by the prohibitive cost of cathode material, especially when platinum is used to catalyze oxygen reduction. In this study, recycled scrap metals could be used efficiently as cathode material in a specially-designed MFC. In terms of raw power, the scrap metals ranked as follows: W/Co > Cu/Ni > Inconel 718 > carpenter alloy; however, in terms of cost and long term stability, Inconel 718 was the preferred choice. Treatment performance--assessed on real and synthetic wastewater--was considerably improved either by filling the anode compartment with carbon granules or by operating the MFC in full-loop mode. The latter option allowed reaching 99.7% acetate removal while generating a maximum power of 36 W m(-3) at an acetate concentration of 2535 mg L(-1). Under these conditions, the energy produced by the system averaged 0.1 kWh m(-3) of wastewater treated. PMID:23138054

  4. Advanced cathode materials for polymer electrolyte fuel cells based on pt/ metal oxides: from model electrodes to catalyst systems.

    PubMed

    Fabbri, Emiliana; Pătru, Alexandra; Rabis, Annett; Kötz, Rüdiger; Schmidt, Thomas J

    2014-01-01

    The development of stable catalyst systems for application at the cathode side of polymer electrolyte fuel cells (PEFCs) requires the substitution of the state-of-the-art carbon supports with materials showing high corrosion resistance in a strongly oxidizing environment. Metal oxides in their highest oxidation state can represent viable support materials for the next generation PEFC cathodes. In the present work a multilevel approach has been adopted to investigate the kinetics and the activity of Pt nanoparticles supported on SnO2-based metal oxides. Particularly, model electrodes made of SnO2 thin films supporting Pt nanoparticles, and porous catalyst systems made of Pt nanoparticles supported on Sb-doped SnO2 high surface area powders have been investigated. The present results indicate that SnO2-based supports do not modify the oxygen reduction reaction mechanism on the Pt nanoparticle surface, but rather lead to catalysts with enhanced specific activity compared to Pt/carbon systems. Different reasons for the enhancement in the specific activity are considered and discussed.

  5. Dispersion and thermal interactions of molten metal fuel settling on a horizontal steel plate through a sodium pool

    SciTech Connect

    Gabor, J.D.; Purviance, R.T.; Aeschlimann, R.W.; Spencer, B.W.

    1989-01-01

    Although the Integral Fast Reactor (IFR) possesses inherent safety features, an assessment of the consequences of melting of the metal fuel is necessary for risk analysis. As part of this effort an experimental study was conducted to determine the depths of sodium at 600 C required for pour streams of various molten uranium alloys (U, U-5 wt % Zr, U-10 wt % Zr, and U-10 wt % Fe) to break up and solidify. The quenched particulate material, which was in the shape of filaments and sheets, formed coolable beds because of the high voidage ({approximately}0.9) and large particle size ({approximately}10 mm). In a test with a 0.15-m sodium depth, the fragments from a pure uranium pour stream did not completely solidify but formed an agglomerated mass which did not fuse to the base plate. However, the agglomerated fragments of U-10 wt % Fe eutectic fused to the stainless steel base plate. An analysis of the temperature response of a 25-mm thick base plate was made by volume averaging the properties of the sodium and metal particle phases and assuming two semi-infinite solids coming into contact. Good agreement was obtained with the data during the initial 5 to 10 s of the contact period. 16 refs., 5 figs., 1 tab.

  6. Steelmaking using a solid metallic charge. Electric or fuel melting units?

    NASA Astrophysics Data System (ADS)

    Gudim, Yu. A.; Zinurov, I. Yu.

    2011-12-01

    A continuously operating MAGMA plant is proposed as an alternative to a superpower arc steel-melting furnace in order to increase the utilization of the heat of primary energy carriers and the liquid semiproduct yield in melting of a solid metal charge. The principle of operation of this plant is described, and its operation characteristics are presented in comparison with those of modern electric-steelmaking furnaces.

  7. A low-Cr metallic interconnect for intermediate-temperature solid oxide fuel cells

    SciTech Connect

    Geng, Shujiang; Zhu, Jiahong; Brady, Michael P; Anderson, Harlan; ZHOU, XIADONG; YANG, ZHENGUO

    2007-01-01

    Solid oxide fuel cells (SOFCs) have attracted significant attention due to the potential for environmentally-friendly power generation with high efficiency, fuel flexibility, and zero/no emissions. However, the main hurdles thwarting the commercial introduction of SOFCs are the stack cost and durability, particularly related to the long-term stability of stack/cell materials such as the interconnect 1-3. There has been recent interest in utilizing the Cr2O3-forming alloys as interconnect for intermediate-temperature SOFCs4-6. As a consequence, volatile Cr species from the Cr2O3 scale can cause severe degradation of electrical and catalytic properties of the cathode7-9. Here, we report a new low-Cr Fe-Co-Ni base alloy that demonstrates a close match in coefficient of thermal expansion (CTE) with adjacent cell components; good oxidation resistance; and low oxide scale area specific resistance (ASR). The formation of a Cr-free (Fe,Co,Ni)3O4 spinel outer layer over the chromia inner layer upon thermal exposure effectively reduces the chromium evaporation.

  8. Tolerance of non-platinum group metals cathodes proton exchange membrane fuel cells to air contaminants

    NASA Astrophysics Data System (ADS)

    Reshetenko, Tatyana; Serov, Alexey; Artyushkova, Kateryna; Matanovic, Ivana; Sarah Stariha; Atanassov, Plamen

    2016-08-01

    The effects of major airborne contaminants (SO2, NO2 and CO) on the spatial performance of Fe/N/C cathode membrane electrode assemblies were studied using a segmented cell system. The injection of 2-10 ppm SO2 in air stream did not cause any performance decrease and redistribution of local currents due to the lack of stably adsorbed SO2 molecules on Fe-Nx sites, as confirmed by density functional theory (DFT) calculations. The introduction of 5-20 ppm of CO into the air stream also did not affect fuel cell performance. The exposure of Fe/N/C cathodes to 2 and 10 ppm NO2 resulted in performance losses of 30 and 70-75 mV, respectively. DFT results showed that the adsorption energies of NO2 and NO were greater than that of O2, which accounted for the observed voltage decrease and slight current redistribution. The cell performance partially recovered when the NO2 injection was stopped. The long-term operation of the fuel cells resulted in cell performance degradation. XPS analyses of Fe/N/C electrodes revealed that the performance decrease was due to catalyst degradation and ionomer oxidation. The latter was accelerated in the presence of air contaminants. The details of the spatial performance and electrochemical impedance spectroscopy results are presented and discussed.

  9. CoxFe1-x oxide coatings on metallic interconnects for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Shen, Fengyu; Lu, Kathy

    2016-10-01

    In order to improve the performance of Cr-containing steel as an interconnect material for solid oxide fuel cells, CoFe alloy coatings with Co:Fe ratios of 9:1, 8:2, 7:3, 6:4, and 5:5 are deposited by electrodeposition and then oxidized to CoxFe1-x oxide coatings with a thickness of ∼6 μm as protective layers on the interconnect. The area specific resistance of the coated interconnect increases with the Fe content. Higher Co content oxide coatings are more effective in limiting the growth of the chromia scale while all coatings are effective in inhibiting Cr diffusion and evaporation. With the Co0.8Fe0.2 oxide coated interconnect, the electrochemical performance of the Sm0.5Sr0.5Co0.2Fe0.8O3 cathode is improved. Only 1.54 atomic percentage of Cr is detected on the surface of the Sm0.5Sr0.5Co0.2Fe0.8O3 cathode while no Cr is detected 0.66 μm or more into the cathode. CoxFe1-x oxide coatings are promising candidates for solid oxide fuel cell interconnects with the advantage of using existing cathode species for compatibility and performance enhancement.

  10. Tolerance of non-platinum group metals cathodes proton exchange membrane fuel cells to air contaminants

    NASA Astrophysics Data System (ADS)

    Reshetenko, Tatyana; Serov, Alexey; Artyushkova, Kateryna; Matanovic, Ivana; Sarah Stariha; Atanassov, Plamen

    2016-08-01

    The effects of major airborne contaminants (SO2, NO2 and CO) on the spatial performance of Fe/N/C cathode membrane electrode assemblies were studied using a segmented cell system. The injection of 2-10 ppm SO2 in air stream did not cause any performance decrease and redistribution of local currents due to the lack of stably adsorbed SO2 molecules on Fe-Nx sites, as confirmed by density functional theory (DFT) calculations. The introduction of 5-20 ppm of CO into the air stream also did not affect fuel cell performance. The exposure of Fe/N/C cathodes to 2 and 10 ppm NO2 resulted in performance losses of 30 and 70-75 mV, respectively. DFT results showed that the adsorption energies of NO2 and NO were greater than that of O2, which accounted for the observed voltage decrease and slight current redistribution. The cell performance partially recovered when the NO2 injection was stopped. The long-term operation of the fuel cells resulted in cell performance degradation. XPS analyses of Fe/N/C electrodes revealed that the performance decrease was due to catalyst degradation and ionomer oxidation. The latter was accelerated in the presence of air contaminants. The details of the spatial performance and electrochemical impedance spectroscopy results are presented and discussed.

  11. Influence of the Piping-material-originated Metal-ion on Cell Degradation of Polymer Electrolyte Fuel Cell

    NASA Astrophysics Data System (ADS)

    Amitani, Chieko; Ishikawa, Masahiko; Mori, Kouya; Tanaka, Kenji; Hori, Michio

    Influences of metal-ion adulterations into Polymer Electrolyte Fuel Cells (PEFC) were examined on PEFC generation characteristics and structural changes. Cupper and aluminun, novel candidate materials for forthcoming PEFC system, were introduced into polymer electrolyte membranes (PEM) by ion-exchange method as contaminants, and ca. 500-hour generation tests of PEFC cells with these PEMs were conducted in this study. Introduced metal ions were to be combined to sulfonic acid groups in PEMs by electrostatic forces. For the cell containing cupric ions (Cu2+) equivalent to 1000 pmm of supfonic acid groups in PEM, a decrease in deteriorating rate of cell voltage was observed to be 83 mV/kh during 500-hour generation, in comparison with the cell without metal-ion comtamination showing 154 mV/kh. On the other hand, an increase in deteriorating rates were observed for the cells containing 10 % Cu2+ or 1000 ppm aluminum ions (Al3+). Al3+ adulteration in PEFC set off increases in activation overpotential and fluoride ion release rate (FRR) with proceeding genaration test. An increase in activation overpotentials was supressed in 1000 ppm Cu2+-adulterated cell and the reverse was observed in 10 % Cu2+-adulterated one, though Cu2+ adulterations suppressed growths of platinum catalyst particles in size and FRR regardless of Cu2+ concentration. Restriction effect of 1000 ppm Cu2+-adulteration into PEM on PEFC voltage deterioration has found to be the unprecedented knoledge with respect to PEFC degradation phenomena. Mechanisms of those influences were also discussed.

  12. Elucidating the mechanism of Cr(VI) formation upon the interaction with metal oxides during coal oxy-fuel combustion.

    PubMed

    Chen, Juan; Jiao, Facun; Zhang, Lian; Yao, Hong; Ninomiya, Yoshihiko

    2013-10-15

    The thermodynamics underpinning the interaction of Cr-bearing species with basic metal oxides, i.e. K2O, Fe2O3, MgO and CaO, during the air and oxy-fuel combustion of coal have been examined. The synchrotron-based X-ray adsorption near-edge spectroscopy (XANES) was used for Cr speciation. For the oxides tested, Cr(VI) formation is dominated by the reduction potential of the metals. The oxides of Ca(2+) with high reduction potential favored the oxidation of Cr(III), same for K(+). The other two basic metals, Fe2O3 and MgO with lower reduction potentials reacted with Cr(III) to form the corresponding chromites at the temperatures above 600°C. Coal combustion experiments in drop-tube furnace have confirmed the rapid capture of Cr vapors, either trivalent or hexavalent, by CaO into solid ash. The existence of HCl in flue gas favored the vaporization of Cr as CrO2Cl2, which was in turn captured by CaO into chromate. Both Fe2O3 and MgO exhibited less capability on scavenging the Cr(VI) vapor. Particularly, MgO alone exhibited a low capability for capturing the vaporized Cr(III) vapors. However, its co-existence with CaO in the furnace inhibited the Cr(VI) formation. This is beneficial for minimizing the toxicity of Cr in the coal combustion-derived fly ash. PMID:23969010

  13. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1992-05-29

    An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a nonswelling solvent to eliminate any spin probes that are not trapped in the pores and the spin concentration measured. Comparing these spin probe measurements to DRIFT data have shown that the relative number distribution of acidic functionalities can be accurately predicted by the spin probe method. The spin probe method has also been used to predict the increase in elongated voids in Pittsburgh No. 8 (APCS No. 4) upon swelling with pyridine in agreement with independent SANS data. NMR relaxation data show that it is possible to deduce the pore (accessibility) distribution as a function of size (up to 6 nm). It has also been possible by variable temperature and ENDOR measurements to determine the presence of hydrogen bonding as a function of pore shape and size. The advantage of EPR method is that it permits molecules of selected shape and size to be used as probes of accessible regions of the coal, thus providing information on the importance of molecular shape.

  14. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1992-08-01

    An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a nonswelling solvent to eliminate any spin probes that are not trapped in the pores and the spin concentration measured. Comparing these spin probe measurements to DRIFT data have shown that the relative number distribution of acidic functionalities can be accurately predicted by the spin probe method. The spin probe method has also been used to predict the increase in elongated voids in Pittsburgh No. 8 (APCS No. 4) upon swelling with pyridine in agreement with independent SANS data. NMR relaxation data shows that it is possible to deduce the pore (accessibility) distribution as a function of size (up to 6 nm). It has also been possible by variable temperature and ENDOR measurements to determine the presence of hydrogen bonding as a function of pore shape and size. The advantage of the EPR method is that it permits molecules of selected shape and size to be used as probes of accessible regions of the coal, thus providing information on the importance of molecular shape.

  15. Bimodal swelling responses in microgel thin films.

    PubMed

    Sorrell, Courtney D; Lyon, L Andrew

    2007-04-26

    A series of studies on microgel thin films is described, wherein quartz crystal microgravimetry (QCM), surface plasmon resonance (SPR), and atomic force microscopy (AFM) have been used to probe the properties of microstructured polymer thin films as a function of film architecture and solution pH. Thin films composed of pNIPAm-co-AAc microgels were constructed by using spin-coating layer-by-layer (scLbL) assembly with poly(allylamine hydrochloride) (PAH) as a polycationic "glue". Our findings suggest that the interaction between the negatively charged microgels and the positively charged PAH has a significant impact on the pH responsivity of the film. These effects are observable in both the optical and mechanical behaviors of the films. The most significant changes in behavior are observed when the motional resistance of a quartz oscillator is monitored via QCM experiments. Slight changes to the film architecture and alternating the pH of the environment significantly changes the QCM and SPR responses, suggesting a pH-dependent swelling that is dependent on both particle swelling and polyelectrolyte de-complexation. Together, these studies allow for a deeper understanding of the morphological changes that take place in environmentally responsive microgel-based thin films. PMID:17407344

  16. Water uptake and swelling hysteresis in a nafion thin film measured with neutron reflectometry.

    PubMed

    Kalisvaart, W Peter; Fritzsche, Helmut; Mérida, Walter

    2015-05-19

    Water uptake and swelling in a thin (∼15 nm) Nafion film on SiO2 native oxide on a Si wafer is studied as a function of relative humidity (8-97%) at room temperature and as a function of temperature (25-60 °C) at 97% relative humidity by neutron reflectometry. This is the first report on the behavior of thin Nafion films at elevated temperatures and high humidity. Large hysteresis is observed during the temperature cycle. The observed swelling strain in the film at 60 °C is 48% as compared to the as-deposited state, which is far above any previously observed trend at room temperature. A small decrease in the average SLD suggests that part of the additional swelling is due to thermal expansion, but the estimated D2O/SO3 ratio also increases by 70%. Half of the "excess" absorption and 73% of the additional swelling are retained during cooling back to room temperature. The results provide new insights into the dynamics of Nafion on nanometer scales under fuel cell operating conditions. PMID:25901752

  17. Metal/ceria water-gas shift catalysts for automotive polymer electrolyte fuel cell system.

    SciTech Connect

    Myers, D. J.; Krebs, J. F.; Carter, J. D.; Kumar, R.; Krumpelt, M.

    2002-01-11

    Polymer electrolyte fuel cell (PEFC) systems are a leading candidate for replacing the internal combustion engine in light duty vehicles. One method of generating the hydrogen necessary for the PEFC is reforming a liquid fuel, such as methanol or gasoline, via partial oxidation, steam reforming, or autothermal reforming (a combination of partial oxidation and steam reforming). The H{sub 2}-rich reformate can contain as much as 10% carbon monoxide. Carbon monoxide has been shown to poison the platinum-based anode catalyst at concentrations as low as 10 ppm,1 necessitating removal of CO to this level before passing the reformate to the fuel cell stack. The water-gas shift (WGS) reaction, CO + H{sub 2}O {rightleftharpoons} CO{sub 2} + H{sub 2}, is used to convert the bulk of the reformate CO to CO{sub 2}. Industrially, the WGS reaction is conducted over two catalysts, which operate in different temperature regimes. One catalyst is a FeCr mixed oxide, which operates at 350-450 C and is termed the high-temperature shift (HTS) catalyst. The second catalyst is a CuZn mixed oxide, which operates at 200-250 C and is termed the low-temperature shift (LTS) catalyst. Although these two catalysts are used industrially in the production of H{sub 2} for ammonia synthesis, they have major drawbacks that make them unsuitable for transportation applications. Both the LTS and the HTS catalysts must first be ''activated'' before being used. For example, the copper in the copper oxide/zinc oxide LTS catalyst must first be reduced to elemental copper in situ before it becomes active for the WGS reaction. This reduction reaction is exothermic and must be carried out under well- controlled conditions using a dilute hydrogen stream (1 vol% H{sub 2}) to prevent high catalyst temperatures, which can result in sintering (agglomeration) of the copper particles and loss of active surface area for the WGS reaction. Also, once the catalyst has been activated by reduction, it must be protected

  18. Advanced Fuel Cycle Initiative AFC-1D, AFC-1G, and AFC-1H End of FY-07 Irradiation Report

    SciTech Connect

    Debra J Utterbeck; Gray S Chang; Misit A Lillo

    2007-09-01

    The purpose of the U.S. Advanced Fuel Cycle Initiative (AFCI), now within the broader context of the Global Nuclear Energy Partnership (GNEP), is to develop and demonstrate the technologies needed to transmute the long-lived transuranic isotopes contained in spent nuclear fuel into shorter-lived fission products. Success in this undertaking could potentially dramatically decrease the volume of material requiring disposal with attendant reductions in long-term radio-toxicity and heat load of high-level waste sent to a geologic repository. One important component of the technology development is investigation of irradiation/transmutation effects on actinide-bearing metallic fuel forms containing plutonium, neptunium, americium (and possibly curium) isotopes. Goals of this initiative include addressing the limited irradiation performance data available on metallic fuels with high concentrations of Pu, Np and Am, as are envisioned for use as actinide transmutation fuels. The AFC-1 irradiation experiments of transmutation fuels are expected to provide irradiation performance data on non-fertile and low-fertile fuel forms specifically, irradiation growth and swelling, helium production, fission gas release, fission product and fuel constituent migration, fuel phase equilibria, and fuel-cladding chemical interaction. Contained in this report are the to-date physics evaluations performed on three of the AFC-1 experiments; AFC-1D, AFC-1G and AFC-1H. The AFC-1D irradiation experiment consists of metallic non-fertile fuel compositions with minor actinides for potential use in accelerator driven systems and AFC-1G and AFC-1H irradiation experiments are part of the fast neutron reactor fuel development effort. The metallic fuel experiments and nitride experiment are high burnup analogs to previously irradiated experiments and are to be irradiated to = 40 at.% burnup.

  19. Irradiation creep relaxation of void swelling-driven stresses

    NASA Astrophysics Data System (ADS)

    Hall, M. M.

    2013-01-01

    Swelling-driven-creep test specimens are used to measure the compressive stresses that develop due to constraint of irradiation void swelling. These specimens use a previously non-irradiated 20% CW Type 316 stainless steel holder to axially restrain two Type 304 stainless steel tubular specimens that were previously irradiated in the US Experimental Breeder Reactor (EBR-II) at 490 °C. One specimen was previously irradiated to fluence levels in the void nucleation regime (9 dpa) and the other in the quasi-steady void growth regime (28 dpa). A lift-off compliance measurement technique was used post-irradiation to determine compressive stresses developed during reirradiation of the two specimen assemblies in Row 7 of EBR-II at temperatures of 547 °C and 504 °C, respectively, to additional damage levels each of about 5 dpa. Results obtained on the higher fluence swelling-driven-creep specimen show that compressive stress due to constraint of swelling retards void swelling to a degree that is consistent with active load uniaxial compression specimens that were irradiated as part of a previously reported multiaxial in-reactor creep experiment. Swelling results obtained on the lower fluence swelling-driven creep specimen show a much larger effect of compressive stress in reducing swelling, demonstrating that the larger effect of stress on swelling is on void nucleation as compared to void growth. Test results are analyzed using a recently proposed multiaxial creep-swelling model.

  20. Metal-ceramic/ceramic nanostructured layered composites for solid oxide fuel cells by spark plasma sintering.

    PubMed

    Bezdorozhev, Oleksii; Borodianska, Hanna; Sakka, Yoshio; Vasylkiv, Oleg

    2014-06-01

    In this work, bi-layered Fe-Ni-Co-YSZ/YSZ nanostructured composites for solid oxide fuel cells were obtained using the spark plasma sintering (SPS) technique. The microstructures of the anode and electrolyte were controlled by optimization of SPS consolidation parameters. The resulting bilayers have a full dense YSZ electrolyte and porous Fe-Ni-Co/YSZ anode as well as crack-free and well-bonded anode/electrolyte interface. On the other hand, SPS under non-optimized processing parameters cannot yield the desired results. The high resistance to thermal stresses of the fabricated half-cells was achieved with Fe-Ni-Co/YSZ anode. The developed anode showed higher thermal compatibility with YSZ electrolyte than usual Ni/YSZ cermet. Thus, with the successful combination of SPS parameters and anode material, we have obtained bi-layers for SOFCs with required microstructure and thermal compatibility.

  1. AB INITIO STUDY OF ADVANCED METALLIC NUCLEAR FUELS FOR FAST BREEDER REACTORS

    SciTech Connect

    Landa, A; Soderlind, P; Grabowski, B; Turchi, P A; Ruban, A V; Vitos, L

    2012-04-23

    Density-functional formalism is applied to study the ground state properties of {gamma}-U-Zr and {gamma}-U-Mo solid solutions. Calculated heats of formation are compared with CALPHAD assessments. We discuss how the heat of formation in both alloys correlates with the charge transfer between the alloy components. The decomposition curves for {gamma}-based U-Zr and U-Mo solid solutions are derived from Ising-type Monte Carlo simulations. We explore the idea of stabilization of the {delta}-UZr{sub 2} compound against the {alpha}-Zr (hcp) structure due to increase of Zr d-band occupancy by the addition of U to Zr. We discuss how the specific behavior of the electronic density of states in the vicinity of the Fermi level promotes the stabilization of the U{sub 2}Mo compound. The mechanism of possible Am redistribution in the U-Zr and U-Mo fuels is also discussed.

  2. Electrical contacts between cathodes and metallic interconnects in solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Yang, Zhenguo; Xia, Guanguang; Singh, Prabhakar; Stevenson, Jeffry W.

    In this work, simulated cathode/interconnect structures were used to investigate the effects of different contact materials on the contact resistance between a strontium doped lanthanum ferrite cathode and a Crofer22 APU interconnect. Among the materials studied, Pt, which has a prohibitive cost for the application, demonstrated the best performance as a contact paste. For the relatively cost-effective perovskites, the contact ASR was found to depend on their electrical conductivity, scale growth on the metallic interconnect, and interactions between the contact material and the metallic interconnect or particularly the scale grown on the interconnect. Manganites appeared to promote manganese-containing spinel interlayer formation that helped minimize the increase of contact ASR. Chromium from the interconnects reacted with strontium in the perovskites to form SrCrO 4. An improved performance was achieved by application of a thermally grown (Mn,Co) 3O 4 spinel protection layer on Crofer22 APU that dramatically minimized the contact resistance between the cathodes and interconnects.

  3. The sodium-bonding pin concept for advanced fuels part II: analysis of the cladding carburization

    SciTech Connect

    Ronchi, C.; Blank, M.; Coguerelle, M.; Rouault, J.

    1984-10-01

    Cladding carburization in irradiated liquid-metal fast breeder reactor carbide pins is analyzed with particular emphasis on sodium-bonding conditions. Original data from the French Project for advanced fuels and the Swelling Project performed by the European Institute for Transuranium Elements are discussed and compared with published results. The mechanisms of carbon transfer from the fuel to the steel cladding are examined and evaluated concluding that cladding carburization cannot be avoided with the present sodium-bonded pin design if hyperstoichiometric fuel is adopted. An assessment of the pin failure risks involved is made for different steels. Austenitic steels customarily used for cladding do not exhibit a fully satisfactory carburization resistance. Recently developed ferritic alloys are suggested for carbide fuel cladding in future applications.

  4. Magnetic relaxation: Coal swelling, extraction, pore size

    SciTech Connect

    Doetschman, D.C.

    1992-11-06

    The goals for year I of the grant were to extract the Argonne Coals, to swell them, to reswell their residues, to seal the various samples for measurements, to perform analyses of the samples and to measure their NMR decays. Because of an unexpected characteristic of the extraction process, more detailed analyses of the samples are being done than originally anticipated. The mass spectrometric analyses have not been completed. Because routine NMR analyses needed to be done in greater detail than anticipated, the NMR decay measurements have also been delayed. In order to offset these delays, all of the EPR samples, which were to have been examined in year III, have been prepared and a substantial proportion of the pulsed EPR measurements have been made.

  5. High Performance Ceramic Interconnect Material for Solid Oxide Fuel Cells (SOFCs): Ca- and Transition Metal-doped Yttrium Chromite

    SciTech Connect

    Yoon, Kyung J.; Stevenson, Jeffry W.; Marina, Olga A.

    2011-10-15

    The effect of transition metal substitution on thermal and electrical properties of Ca-doped yttrium chromite was investigated in relation to use as a ceramic interconnect in high temperature solid oxide fuel cells (SOFCs). 10 at% Co, 4 at% Ni, and 1 at% Cu substitution on B-site of 20 at% Ca-doped yttrium chromite led to a close match of thermal expansion coefficient (TEC) with that of 8 mol% yttria-stabilized zirconia (YSZ), and a single phase Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 remained stable between 25 and 1100 degree C over a wide oxygen partial pressure range. Doping with Cu significantly facilitated densification of yttrium chromite. Ni dopant improved both electrical conductivity and dimensional stability in reducing environments, likely through diminishing the oxygen vacancy formation. Substitution with Co substantially enhanced electrical conductivity in oxidizing atmosphere, which was attributed to an increase in charge carrier density and hopping mobility. Electrical conductivity of Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 at 900 degree C is 57 S/cm in air and 11 S/cm in fuel (pO2=5×10^-17 atm) environments. Chemical compatibility of doped yttrium chromite with other cell components was verified at the processing temperatures. Based on the chemical and dimensional stability, sinterability, and thermal and electrical properties, Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 is suggested as a promising SOFC ceramic interconnect to potentially overcome technical limitations of conventional acceptor-doped lanthanum chromites.

  6. High performance ceramic interconnect material for solid oxide fuel cells (SOFCs): Ca- and transition metal-doped yttrium chromite

    NASA Astrophysics Data System (ADS)

    Yoon, Kyung Joong; Stevenson, Jeffrey W.; Marina, Olga A.

    2011-10-01

    The effect of transition metal substitution on thermal and electrical properties of Ca-doped yttrium chromite was investigated in relation to use as a ceramic interconnect in high temperature solid oxide fuel cells (SOFCs). 10 at.% Co, 4 at.% Ni, and 1 at.% Cu substitution on B-site of 20 at.% Ca-doped yttrium chromite led to a close match of thermal expansion coefficient (TEC) with that of 8 mol% yttria-stabilized zirconia (YSZ), and a single phase Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 remained stable between 25 and 1100 °C over a wide oxygen partial pressure range. Doping with Cu significantly facilitated densification of yttrium chromite. Ni dopant improved both electrical conductivity and dimensional stability in reducing environments, likely through diminishing the oxygen vacancy formation. Substitution with Co substantially enhanced electrical conductivity in oxidizing atmosphere, which was attributed to an increase in charge carrier density and hopping mobility. Electrical conductivity of Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 at 900 °C is 57 S cm-1 in air and 11 S cm-1 in fuel (pO2 = 5 × 10-17 atm) environments. Chemical compatibility of doped yttrium chromite with other cell components was verified at the processing temperatures. Based on the chemical and dimensional stability, sinterability, and thermal and electrical properties, Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 is suggested as a promising SOFC ceramic interconnect to potentially overcome technical limitations of conventional acceptor-doped lanthanum chromites.

  7. Reducing the deactivation of Ni-metal during the catalytic partial oxidation of a surrogate diesel fuel mixture

    SciTech Connect

    Haynes, Daniel J.; Campos, Andrew; Smith, Mark W.; Berry, David A.; Shekhawat, Dushyant; Spivey, James J.

    2010-09-01

    Ni catalysts are active and selective for the conversion of hydrocarbon into synthesis gas. However, conventional supported Ni catalysts rapidly deactivate at the high temperatures required for partial oxidation of diesel fuel by sintering and metal vaporization, as well as by carbon deposition and sulfur poisoning. Thus, to reduce deactivation Ni (3 wt%) was substituted into the structures of Ba-hexaaluminate (BNHA) and La–Sr–Zr pyrochlore (LSZN), and their activity was compared to a supported Ni/Al2O3 for the catalytic partial oxidation (CPOX) of a surrogate diesel fuel. Characterization by XRD showed a single phase β-alumina for the hexaaluminate, while LSZN had a pyrochlore structure with a defect SrZrO3 perovskite phase. Temperature programmed reduction experiments confirmed Ni was reducible in all catalysts. XANES results confirmed that Ni atoms were substituted into the hexaaluminate and pyrochlore structures, as spectra for each catalyst showed different coordination environments for Ni compared to a NiO standard. During CPOX activity tests (T = 900 °C and WHSV = 50,000 scc/gcat/h), the LSZN pyrochlore produced stable H2 and CO yields in the presence of 5 wt% 1-methylnaphthalene and 50 ppmw dibenzothiophene/n-tetradecane for 2 h, while both Ni/Al2O3 and BNHA catalysts were irreversibly deactivated by this mixture over the same time. Finally, activity loss was strongly linked to carbon formation.

  8. A simple model for the swelling of polymer networks

    SciTech Connect

    Painter, P.C.; Shenoy, S.L. )

    1993-07-15

    The Flory--Rehner approach to the solvent swelling of polymer networks is modified so as to abandon the affine deformation assumption. Instead, it is assumed that swelling occurs by a process of disinterspersion of cross-link junctions, and relationships between chain expansion and segment concentration are established using the ideas of de Gennes. Using this approach, we also examine osmotic deswelling, aspects of phase equilibria, and the maximum observed in differential swelling measurements.

  9. Studies involving high temperature desulfurization/regeneration reactions of metal oxides for fuel cell development

    NASA Astrophysics Data System (ADS)

    Jalan, V.

    1983-10-01

    A high temperature regenerable desulfurization process capable of reducing the sulfur content in coal gases from 200 pp to 1 ppm was investigated to provide for the integration of a coal gasifier with a molten carbonate fuel cell, which requires that the sulfur content be below 1 ppm. Results obtained with packed-bed and fluidized-bed reactors have demonstrated that a CuO/ZnO mixed oxide sorbent is regenerble and capable of lowering the sulfur content (as H2s and COS) from 200 ppm in simulated hot coal-derived gases to below 1 ppm level at 600 to 650 C. A comprecipitated CuO/ZnO was elected for further study. A structural reorganization mechanism, unique to mixed oxides, was identified: the creation of relatively fine crystallites of the sulfide components (Cu2S and ZnS) to counteract the loss of surface area due to sintering during regeneration. Studies with 9 to 26% water vapor in simulated coal gases show that sulfur levels below 1 ppm can be achieved in the temperature range of 500 to 650 C. The ability of CuO/ZnO to remove COS, CS2 and CH3SH at these conditions was demonstrated. A previously proposed pore-plugging model was further developed with good success for data treatment of both packed-bed and fluidized-bed reactors.

  10. Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

    NASA Astrophysics Data System (ADS)

    Hu, Shenyang; Burkes, Douglas E.; Lavender, Curt A.; Senor, David J.; Setyawan, Wahyu; Xu, Zhijie

    2016-10-01

    Nano-gas bubble superlattices are often observed in irradiated UMo nuclear fuels. However, the formation mechanism of gas bubble superlattices is not well understood. A number of physical processes may affect the gas bubble nucleation and growth; hence, the morphology of gas bubble microstructures including size and spatial distributions. In this work, a phase-field model integrating a first-passage Monte Carlo method to investigate the formation mechanism of gas bubble superlattices was developed. Six physical processes are taken into account in the model: 1) heterogeneous generation of gas atoms, vacancies, and interstitials informed from atomistic simulations; 2) one-dimensional (1-D) migration of interstitials; 3) irradiation-induced dissolution of gas atoms; 4) recombination between vacancies and interstitials; 5) elastic interaction; and 6) heterogeneous nucleation of gas bubbles. We found that the elastic interaction doesn't cause the gas bubble alignment, and fast 1-D migration of interstitials along <110> directions in the body-centered cubic U matrix causes the gas bubble alignment along <110> directions. It implies that 1-D interstitial migration along [110] direction should be the primary mechanism of a fcc gas bubble superlattice which is observed in bcc UMo alloys. Simulations also show that fission rates, saturated gas concentration, and elastic interaction all affect the morphology of gas bubble microstructures.

  11. EQ6 Calculations for Chemical Degradation Of N Reactor (U-Metal) Spent Nuclear Fuel Waste Packages

    SciTech Connect

    P. Bernot

    2001-02-27

    The Monitored Geologic Repository (MGR) Waste Package Department of the Civilian Radioactive Waste Management System Management & Operating Contractor (CRWMS M&O) performed calculations to provide input for disposal of spent nuclear fuel (SNF) from the N Reactor, a graphite moderated reactor at the Department of Energy's (DOE) Hanford Site (ref. 1). The N Reactor core was fueled with slightly enriched (0.947 wt% and 0.947 to 1.25 wt% {sup 235}U in Mark IV and Mark IA fuels, respectively) U-metal clad in Zircaloy-2 (Ref. 1, Sec. 3). Both types of N Reactor SNF have been considered for disposal at the proposed Yucca Mountain site. For some WPs, the outer shell and inner shell may breach (Ref. 3) allowing the influx of water. Water in the WP will moderate neutrons, increasing the likelihood of a criticality event within the WP; and the water may, in time, gradually leach the fissile components from the WP, further affecting the neutronics of the system. This study presents calculations of the long-term geochemical behavior of WPs containing two multi-canister overpacks (MCO) with either six baskets of Mark IA or five baskets of Mark IV intact N Reactor SNF rods (Ref. 1, Sec. 4) and two high-level waste (HLW) glass pour canisters (GPCs) arranged according to the codisposal concept (Ref. 4). The specific study objectives were to determine: (1) The extent to which fissile uranium will remain in the WP after corrosion/dissolution of the initial WP configuration (2) The extent to which fissile uranium will be carried out of the degraded WP by infiltrating water (such that internal criticality is no longer possible, but the possibility of external criticality may be enhanced); and (3) The nominal chemical composition for the criticality evaluations of the WP design, and to suggest the range of parametric variations for additional evaluations. The scope of this calculation, the chemical compositions (and subsequent criticality evaluations) of the simulations, is limited to

  12. Supported noble metals on hydrogen-treated TiO2 nanotube arrays as highly ordered electrodes for fuel cells.

    PubMed

    Zhang, Changkun; Yu, Hongmei; Li, Yongkun; Gao, Yuan; Zhao, Yun; Song, Wei; Shao, Zhigang; Yi, Baolian

    2013-04-01

    Hydrogen-treated TiO2 nanotube (H-TNT) arrays serve as highly ordered nanostructured electrode supports, which are able to significantly improve the electrochemical performance and durability of fuel cells. The electrical conductivity of H-TNTs increases by approximately one order of magnitude in comparison to air-treated TNTs. The increase in the number of oxygen vacancies and hydroxyl groups on the H-TNTs help to anchor a greater number of Pt atoms during Pt electrodeposition. The H-TNTs are pretreated by using a successive ion adsorption and reaction (SIAR) method that enhances the loading and dispersion of Pt catalysts when electrodeposited. In the SIAR method a Pd activator can be used to provide uniform nucleation sites for Pt and leads to increased Pt loading on the H-TNTs. Furthermore, fabricated Pt nanoparticles with a diameter of 3.4 nm are located uniformly around the pretreated H-TNT support. The as-prepared and highly ordered electrodes exhibit excellent stability during accelerated durability tests, particularly for the H-TNT-loaded Pt catalysts that have been annealed in ultrahigh purity H2 for a second time. There is minimal decrease in the electrochemical surface area of the as-prepared electrode after 1000 cycles compared to a 68 % decrease for the commercial JM 20 % Pt/C electrode after 800 cycles. X-ray photoelectron spectroscopy shows that after the H-TNT-loaded Pt catalysts are annealed in H2 for the second time, the strong metal-support interaction between the H-TNTs and the Pt catalysts enhances the electrochemical stability of the electrodes. Fuel-cell testing shows that the power density reaches a maximum of 500 mWcm(-2) when this highly ordered electrode is used as the anode. When used as the cathode in a fuel cell with extra-low Pt loading, the new electrode generates a specific power density of 2.68 kWg(Pt) (-1) . It is indicated that H-TNT arrays, which have highly ordered nanostructures, could be used as ordered electrode supports.

  13. Processes and controls in swelling anhydritic clay rocks

    NASA Astrophysics Data System (ADS)

    Mutschler, Thomas; Blum, Philipp; Butscher, Christoph

    2015-04-01

    Referring to the swelling of anhydritic clay rocks in tunneling, Leopold Müller-Salzburg noted in the third volume on tunneling of his fundamental text book on rock engineering that "a truly coherent explanation of these phenomena is still owing" (Müller-Salzburg 1978, p. 306). This valuation is still true after more than three decades of research in the field of swelling anhydritic clay rocks. One of the reasons is our limited knowledge of the processes involved in the swelling of such rocks, and of the geological, mineralogical, hydraulic, chemical and mechanical controls of the swelling. In this contribution, a review of processes in swelling anhydritic clay rocks and of associated controls is presented. Also numerical models that aim at simulating the swelling processes and controls are included in this review, and some of the remaining open questions are pointed out. By focusing on process-oriented work in this review, the presentation intends to stimulate further research across disciplines in the field of swelling anhydritic clay rocks to finally get a step further in managing the swelling problem in geotechnical engineering projects. Keywords: swelling; anhydritic clay rocks; review

  14. Clay swelling — A challenge in the oilfield

    NASA Astrophysics Data System (ADS)

    Anderson, R. L.; Ratcliffe, I.; Greenwell, H. C.; Williams, P. A.; Cliffe, S.; Coveney, P. V.

    2010-02-01

    Water-based drilling fluids are increasingly being used for oil and gas exploration, and are generally considered to be more environmentally acceptable than oil-based or synthetic-based fluids. Unfortunately, their use facilitates clay hydration and swelling. Clay swelling, which occurs in exposed sedimentary rock formations, can have an adverse impact on drilling operations and may lead to significantly increased oil well construction costs. Minimizing clay swelling is therefore an important area attracting a large amount of interest from both academia and industry. To effectively reduce the extent of clay swelling the mechanism by which clay minerals swell needs to be understood so that efficient swelling inhibitors may be developed. Acceptable clay swelling inhibitors must not only significantly reduce clay hydration, but must also meet increasingly stringent environmental guidelines while remaining cost effective. The development of these inhibitors, which are generally based upon water soluble polymers, therefore represents a challenge to oilfield geochemistry. This review aims to provide a comprehensive understanding of the mechanism by which clay minerals swell and what steps have been taken in the development of effective and environmentally friendly clay swelling inhibitors.

  15. Tracking the attenuation and nonbreaking dissipation of swells using altimeters

    NASA Astrophysics Data System (ADS)

    Jiang, Haoyu; Stopa, Justin E.; Wang, He; Husson, Romain; Mouche, Alexis; Chapron, Bertrand; Chen, Ge

    2016-02-01

    A method for systematically tracking swells across oceanic basins is developed by taking advantage of high-quality data from space-borne altimeters and wave model output. The evolution of swells is observed over large distances based on 202 swell events with periods ranging from 12 to 18 s. An empirical attenuation rate of swell energy of about 4 × 10-7 m-1 is estimated using these observations, and the nonbreaking energy dissipation rates of swells far away from their generating areas are also estimated using a point source model. The resulting acceptance range of nonbreaking dissipation rates is -2.5 to 5.0 × 10-7 m-1, which corresponds to a dissipation e-folding scales of at least 2000 km for steep swells, to almost infinite for small-amplitude swells. These resulting rates are consistent with previous studies using in-situ and synthetic aperture radar (SAR) observations. The frequency dispersion and angular spreading effects during swell propagation are discussed by comparing the results with other studies, demonstrating that they are the two dominant processes for swell height attenuation, especially in the near field. The resulting dissipation rates from these observations can be used as a reference for ocean engineering and wave modeling, and for related studies such as air-sea and wind-wave-turbulence interactions.

  16. Feasibility study on AFR-100 fuel conversion from uranium-based fuel to thorium-based fuel

    SciTech Connect

    Heidet, F.; Kim, T.; Grandy, C.

    2012-07-30

    Although thorium has long been considered as an alternative to uranium-based fuels, most of the reactors built to-date have been fueled with uranium-based fuel with the exception of a few reactors. The decision to use uranium-based fuels was initially made based on the technology maturity compared to thorium-based fuels. As a result of this experience, lot of knowledge and data have been accumulated for uranium-based fuels that made it the predominant nuclear fuel type for extant nuclear power. However, following the recent concerns about the extent and availability of uranium resources, thorium-based fuels have regained significant interest worldwide. Thorium is more abundant than uranium and can be readily exploited in many countries and thus is now seen as a possible alternative. As thorium-based fuel technologies mature, fuel conversion from uranium to thorium is expected to become a major interest in both thermal and fast reactors. In this study the feasibility of fuel conversion in a fast reactor is assessed and several possible approaches are proposed. The analyses are performed using the Advanced Fast Reactor (AFR-100) design, a fast reactor core concept recently developed by ANL. The AFR-100 is a small 100 MW{sub e} reactor developed under the US-DOE program relying on innovative fast reactor technologies and advanced structural and cladding materials. It was designed to be inherently safe and offers sufficient margins with respect to the fuel melting temperature and the fuel-cladding eutectic temperature when using U-10Zr binary metal fuel. Thorium-based metal fuel was preferred to other thorium fuel forms because of its higher heavy metal density and it does not need to be alloyed with zirconium to reduce its radiation swelling. The various approaches explored cover the use of pure thorium fuel as well as the use of thorium mixed with transuranics (TRU). Sensitivity studies were performed for the different scenarios envisioned in order to determine the

  17. Report of Separate Effects Testing for Modeling of Metallic Fuel Casting Process

    SciTech Connect

    Crapps, Justin M.; Galloway, Jack D.; Decroix, David S.; Korzekwa, David A.; Aikin, Robert M. Jr.; Unal, Cetin; Fielding, R.; Kennedy, R

    2012-06-29

    In order to give guidance regarding the best investment of time and effort in experimental determination of parameters defining the casting process, a Flow-3D model of the casting process was used to investigate the most influential parameters regarding void fraction of the solidified rods and solidification speed for fluid flow parameters, liquid heat transfer parameters, and solid heat transfer parameters. Table 1 summarizes the most significant variables for each of the situations studied. A primary, secondary, and tertiary effect is provided for fluid flow parameters (impacts void fraction) and liquid heat transfer parameters (impacts solidification). In Table 1, the wetting angle represents the angle between the liquid and mold surface as pictured in Figure 1. The viscosity is the dynamic viscosity of the liquid and the surface tension is the property of the surface of a liquid that allows it to resist an external force. When only considering solid heat transfer properties, the variations from case to case were very small. Details on this conclusion are provided in the section considering solid heat transfer properties. The primary recommendation of the study is to measure the fluid flow parameters, specifically the wetting angle, surface tension, and dynamic viscosity, in order of importance, as well as the heat transfer parameters latent heat and specific heat of the liquid alloy. The wetting angle and surface tension can be measured simultaneously using the sessile drop method. It is unclear whether there is a temperature dependency in these properties. Thus measurements for all three parameters are requested at 1340, 1420, and 1500 degrees Celsius, which correspond to the minimum, middle, and maximum temperatures of the liquid alloy during the process. In addition, the heat transfer coefficient between the mold and liquid metal, the latent heat of transformation, and the specific heat of the liquid metal all have strong influences on solidification. These

  18. Tribological Properties of Hard Metal Coatings Sprayed by High-Velocity Air Fuel Process

    NASA Astrophysics Data System (ADS)

    Lyphout, C.; Sato, K.; Houdkova, S.; Smazalova, E.; Lusvarghi, L.; Bolelli, G.; Sassatelli, P.

    2016-01-01

    Lowering the thermal energy and increasing the kinetic energy of hard metal particles sprayed by the newly developed HVAF systems can significantly reduce their decarburization, and increases the sliding wear and corrosion resistance of the resulting coatings, making the HVAF technique attractive, both economically and environmentally, over its HVOF predecessors. Two agglomerated and sintered feedstock powder chemistries, WC-Co (88/12) and WC-CoCr (86/10/4), respectively, with increasing primary carbides grain size from 0.2 to 4.0 microns, have been deposited by the latest HVAF-M3 process onto carbon steel substrates. Their dry sliding wear behaviors and friction coefficients were evaluated at room temperature via Ball-on-disk (ASTM G99-90) wear tests against Al2O3 counterparts, and via Pin-on-disk (ASTM G77-05) wear tests against modified martensitic steel counterparts in both dry and lubricated conditions. Sliding wear mechanisms, with the formation of wavy surface morphology and brittle cracking, are discussed regarding the distribution and size of primary carbides. Corrosion behaviors were evaluated via standard Neutral Salt Spray, Acetic Acid Salt Spray, accelerated corrosion test, and electrochemical polarization test at room temperature. The optimization of the tribological properties of the coatings is discussed, focusing on the suitable selection of primary carbide size for different working load applications.

  19. Novel Compressive Mica Seals with Metallic Interlayers for Solid Oxide Fuel Cell Applications

    SciTech Connect

    Chou, Y. S.; Stevenson, Jeffry W.; Chick, Lawrence A.

    2003-06-15

    A novel hybrid compressive mica seal was developed that showed an exceptionally low leak rate of ~8.9x10-4 sccm/cm at 800 degrees C and a compressive stress of 100 psi, about 740 times lower than that of the conventional compressive mica seals (6.6x10-1 sccm/cm), at a pressure gradient of 2 psi. The hybrid compressive mica seals are composed of two compliant metallic layers and a mica layer. Three commercially available micas were tested in this study. All showed substantial improvements in reducing the leak rates by using the hybrid design. The best results were obtained using Muscovite single crystal mica and 5 mil silver layers. Using the paper-form of Muscovite and Phlogopite mica, the leak rates were still far superior (~1x10-1 sccm/cm) compared to mica without the compliant silver layer (about 6~9 sccm/cm). The microstructure of the mica was examined before and after the 800 degrees C leak tests. These results were also compared with results for hybrid seals using glass interlayers. In addition, an explanation for the substantial reduction of the leak rates was proposed, and the application of the hybrid compressive mica seals in planar SOFC stacks was briefly addressed.

  20. Trace heavy metal ions promoted extracellular electron transfer and power generation by Shewanella in microbial fuel cells.

    PubMed

    Xu, Yu-Shang; Zheng, Tao; Yong, Xiao-Yu; Zhai, Dan-Dan; Si, Rong-Wei; Li, Bing; Yu, Yang-Yang; Yong, Yang-Chun

    2016-07-01

    Although microbial fuel cells (MFCs) is considered as one of the most promising technology for renewable energy harvesting, low power output still accounts one of the bottlenecks and limits its further development. In this work, it is found that Cu(2+) (0.1μgL(-1)-0.1mgL(-1)) or Cd(2+) (0.1μgL(-1)-1mgL(-1)) significantly improve the electricity generation in MFCs. The maximum power output achieved with trace level of Cu(2+) (∼6nM) or Cd(2+) (∼5nM) is 1.3 times and 1.6 times higher than that of the control, respectively. Further analysis verifies that addition of Cu(2+) or Cd(2+) effectively improves riboflavin production and bacteria attachment on the electrode, which enhances bacterial extracellular electron transfer (EET) in MFCs. These results unveil the mechanism for power output enhancement by Cu(2+) or Cd(2+) addition, and suggest that metal ion addition should be a promising strategy to enhance EET as well as power generation of MFCs.

  1. Conversion of light hydrocarbon gases to metal carbides for production of liquid fuels and chemicals. Quarterly technical status report, October 1--December 31, 1992

    SciTech Connect

    Diaz, A.F.; Modestino, A.J.; Howard, J.B.; Peters, W.A.

    1993-02-01

    Light hydrocarbon gases could be reacted with low cost alkaline earth metal oxide (CaO, MgO) in high-temperature plasma reactor to achieve very high ({le}100%) gas conversion to H{sub 2}, CO, and the corresponding metal carbides. These carbides could be stored, transported, and hydrolyzed to acetylene or methyl acetylene, which in turn could be upgraded to a wide range of chemicals and premium liquid hydrocarbon fuels. An electric arc discharge reactor was built for converting methane. Literature reviews were made.

  2. The Molecular Clouds Fueling A 1/5 Solar Metallicity Starburst

    NASA Astrophysics Data System (ADS)

    Kepley, Amanda A.; Leroy, Adam K.; Johnson, Kelsey E.; Sandstrom, Karin; Chen, C.-H. Rosie

    2016-09-01

    Using the Atacama Large Millimeter/submillimeter Array, we have made the first high spatial and spectral resolution observations of the molecular gas and dust in the prototypical blue compact dwarf galaxy II Zw 40. The {}12{CO}(2-1) and {}12{CO}(3-2) emission is clumpy and distributed throughout the central star-forming region. Only one of eight molecular clouds has associated star formation. The continuum spectral energy distribution is dominated by free-free and synchrotron; at 870 μm, only 50% of the emission is from dust. We derive a CO-to-H2 conversion factor using several methods, including a new method that uses simple photodissocation models and resolved CO line intensity measurements to derive a relationship that uniquely predicts {α }{co} for a given metallicity. We find that the CO-to-H2 conversion factor is 4-35 times that of the Milky Way (18.1-150.5 {M}⊙ {({{K}}{km}{{{s}}}-1{{pc}}2)}-1). The star formation efficiency of the molecular gas is at least 10 times higher than that found in normal spiral galaxies, which is likely due to the burst-dominated star formation history of II Zw 40 rather than an intrinsically higher efficiency. The molecular clouds within II Zw 40 resemble those in other strongly interacting systems like the Antennae: overall they have high size-linewidth coefficients and molecular gas surface densities. These properties appear to be due to the high molecular gas surface densities produced in this merging system rather than to increased external pressure. Overall, these results paint a picture of II Zw 40 as a complex, rapidly evolving system whose molecular gas properties are dominated by the large-scale gas shocks from its ongoing merger.

  3. The Molecular Clouds Fueling A 1/5 Solar Metallicity Starburst

    NASA Astrophysics Data System (ADS)

    Kepley, Amanda A.; Leroy, Adam K.; Johnson, Kelsey E.; Sandstrom, Karin; Chen, C.-H. Rosie

    2016-09-01

    Using the Atacama Large Millimeter/submillimeter Array, we have made the first high spatial and spectral resolution observations of the molecular gas and dust in the prototypical blue compact dwarf galaxy II Zw 40. The {}12{CO}(2-1) and {}12{CO}(3-2) emission is clumpy and distributed throughout the central star-forming region. Only one of eight molecular clouds has associated star formation. The continuum spectral energy distribution is dominated by free–free and synchrotron; at 870 μm, only 50% of the emission is from dust. We derive a CO-to-H2 conversion factor using several methods, including a new method that uses simple photodissocation models and resolved CO line intensity measurements to derive a relationship that uniquely predicts {α }{co} for a given metallicity. We find that the CO-to-H2 conversion factor is 4–35 times that of the Milky Way (18.1–150.5 {M}ȯ {({{K}}{km}{{{s}}}-1{{pc}}2)}-1). The star formation efficiency of the molecular gas is at least 10 times higher than that found in normal spiral galaxies, which is likely due to the burst-dominated star formation history of II Zw 40 rather than an intrinsically higher efficiency. The molecular clouds within II Zw 40 resemble those in other strongly interacting systems like the Antennae: overall they have high size–linewidth coefficients and molecular gas surface densities. These properties appear to be due to the high molecular gas surface densities produced in this merging system rather than to increased external pressure. Overall, these results paint a picture of II Zw 40 as a complex, rapidly evolving system whose molecular gas properties are dominated by the large-scale gas shocks from its ongoing merger.

  4. Linearized model for the hydrodynamic stability investigation of molten fuel jets into the coolant of a Liquid Metal Fast Breeder Reactor (LMFBR)

    NASA Astrophysics Data System (ADS)

    Hartel, K.

    1986-02-01

    The hydrodynamic stability of liquid jets in a liquid continuum, both characterized by low viscosity was analyzed. A linearized mathematical model was developed. This model enables the length necessary for fragmentation of a vertical, symmetric jet of molten fuel by hydraulic forces in the coolant of a liquid metal fast breeder reactor to be evaluated. On the basis of this model the FRAG code for numerical calculation of the hydrodynamic fragmentation mechanism was developed.

  5. Application of Neutron-Absorbing Structural-Amorphous Metal (SAM) Coatings for Spent Nuclear Fuel (SNF) Container to Enhance Criticality Safety Controls

    SciTech Connect

    Choi, Jor-Shan; Lee, Chuck; Farmer, Joseph; Day, Dan; Wall, Mark; Saw, Cheng; Boussoufi, Moe; Liu, Ben; Egbert, Harold; Branagan, Dan; D'Amato, Andy

    2007-07-01

    Spent nuclear fuel contains fissionable materials ({sup 235}U, {sup 239}Pu, {sup 241}Pu, etc.). To prevent nuclear criticality in spent fuel storage, transportation, and during disposal, neutron-absorbing materials (or neutron poisons, such as borated stainless steel, Boral{sup TM}, Metamic{sup TM}, Ni-Gd, and others) would have to be applied. The success in demonstrating that the High-Performance Corrosion- Resistant Material (HPCRM){sup [1]} can be thermally applied as coating onto base metal to provide for corrosion resistance for many naval applications raises the interest in applying the HPCRM to USDOE/OCRWM spent fuel management program. The fact that the HPCRM relies on the high content of boron to make the material amorphous - an essential property for corrosion resistance - and that the boron has to be homogeneously distributed in the HPCRM qualify the material to be a neutron poison. (authors)

  6. Conceptual design study on very small long-life gas cooled fast reactor using metallic natural Uranium-Zr as fuel cycle input

    NASA Astrophysics Data System (ADS)

    Monado, Fiber; Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Basar, Khairul; Aziz, Ferhat; Permana, Sidik; Sekimoto, Hiroshi

    2014-02-01

    A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8% HM. From the neutronic point of view, this design is in compliance with good performance.

  7. Conceptual design study on very small long-life gas cooled fast reactor using metallic natural Uranium-Zr as fuel cycle input

    SciTech Connect

    Monado, Fiber; Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Basar, Khairul; Permana, Sidik; Aziz, Ferhat; Sekimoto, Hiroshi

    2014-02-12

    A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8% HM. From the neutronic point of view, this design is in compliance with good performance.

  8. Analysis and prediction of ocean swell using instrumented buoys

    NASA Technical Reports Server (NTRS)

    Mettlach, Theodore; Wang, David; Wittmann, Paul

    1994-01-01

    During the period 20-23 September 1990, the remnants of Supertyphoon Flo moved into the central North Pacific Ocean with sustained wind speeds of 28 m/s. The strong wind and large fetch area associated with this storm generated long-period swell that propagated to the west coast of North America. National Data Buoy Center moored-buoy stations, located in a network that ranged from the Gulf of Alaska to the California Bight, provided wave spectral estimates of the swell from this storm. The greatest dominant wave periods measured were approximately 20-25 s, and significant wave heights measured ranged from 3 to 8 m. Wave spectra from an array of three nondirectional buoys are used to find the source of the long-period swell. Directional wave spectra from a heave-pitch-roll buoy are also used to make an independent estimate of the source of the swell. The ridge-line method, using time-frequency contour plots of wave spectral energy density, is used to determine the time of swell generation, which is used with the appropriate surface pressure analysis to infer the swell generation area. The diagnosed sources of the swell are also compared with nowcasts from the Global Spectral Ocean Wave Model of the Fleet Numerical Oceanography Center. A simple method of predicting the propagation of ocean swell, by applying a simple kinematic model of wave propagation to the estimated point and time source, is demonstrated.

  9. Nanoscale Electrodes for Flexible Electronics by Swelling Controlled Cracking.

    PubMed

    Zhao, Qiang; Wang, Wenjun; Shao, Jinyou; Li, Xiangming; Tian, Hongmiao; Liu, Lu; Mei, Xuesong; Ding, Yucheng; Lu, Bingheng

    2016-08-01

    Nanogap electrodes are realized using pre-patterned electrodes and a swelling controlled cracking method. Parallel fabrication of nanogap electrodes on flexible substrates can be achieved using this method. This swelling-controlled cracking method is promising for fabricating high-performance flexible electronics. UV photodetectors with ZnO nanoparticle-bridged nanogap electrodes exhibit high responsivity and external quantum efficiency.

  10. Nanoscale Electrodes for Flexible Electronics by Swelling Controlled Cracking.

    PubMed

    Zhao, Qiang; Wang, Wenjun; Shao, Jinyou; Li, Xiangming; Tian, Hongmiao; Liu, Lu; Mei, Xuesong; Ding, Yucheng; Lu, Bingheng

    2016-08-01

    Nanogap electrodes are realized using pre-patterned electrodes and a swelling controlled cracking method. Parallel fabrication of nanogap electrodes on flexible substrates can be achieved using this method. This swelling-controlled cracking method is promising for fabricating high-performance flexible electronics. UV photodetectors with ZnO nanoparticle-bridged nanogap electrodes exhibit high responsivity and external quantum efficiency. PMID:27197807

  11. Skeletogenesis in the swell shark Cephaloscyllium ventriosum.

    PubMed

    Eames, B Frank; Allen, Nancy; Young, Jonathan; Kaplan, Angelo; Helms, Jill A; Schneider, Richard A

    2007-05-01

    Extant chondrichthyans possess a predominantly cartilaginous skeleton, even though primitive chondrichthyans produced bone. To gain insights into this peculiar skeletal evolution, and in particular to evaluate the extent to which chondrichthyan skeletogenesis retains features of an osteogenic programme, we performed a histological, histochemical and immunohistochemical analysis of the entire embryonic skeleton during development of the swell shark Cephaloscyllium ventriosum. Specifically, we compared staining properties among various mineralizing tissues, including neural arches of the vertebrae, dermal tissues supporting oral denticles and Meckel's cartilage of the lower jaw. Patterns of mineralization were predicted by spatially restricted alkaline phosphatase activity earlier in development. Regarding evidence for an osteogenic programme in extant sharks, a mineralized tissue in the perichondrium of C. ventriosum neural arches, and to a lesser extent a tissue supporting the oral denticle, displayed numerous properties of bone. Although we uncovered many differences between tissues in Meckel's cartilage and neural arches of C. ventriosum, both elements impart distinct tissue characteristics to the perichondral region. Considering the evolution of osteogenic processes, shark skeletogenesis may illuminate the transition from perichondrium to periosteum, which is a major bone-forming tissue during the process of endochondral ossification. PMID:17451531

  12. Skeletogenesis in the swell shark Cephaloscyllium ventriosum

    PubMed Central

    Eames, B Frank; Allen, Nancy; Young, Jonathan; Kaplan, Angelo; Helms, Jill A; Schneider, Richard A

    2007-01-01

    Extant chondrichthyans possess a predominantly cartilaginous skeleton, even though primitive chondrichthyans produced bone. To gain insights into this peculiar skeletal evolution, and in particular to evaluate the extent to which chondrichthyan skeletogenesis retains features of an osteogenic programme, we performed a histological, histochemical and immunohistochemical analysis of the entire embryonic skeleton during development of the swell shark Cephaloscyllium ventriosum. Specifically, we compared staining properties among various mineralizing tissues, including neural arches of the vertebrae, dermal tissues supporting oral denticles and Meckel's cartilage of the lower jaw. Patterns of mineralization were predicted by spatially restricted alkaline phosphatase activity earlier in development. Regarding evidence for an osteogenic programme in extant sharks, a mineralized tissue in the perichondrium of C. ventriosum neural arches, and to a lesser extent a tissue supporting the oral denticle, displayed numerous properties of bone. Although we uncovered many differences between tissues in Meckel's cartilage and neural arches of C. ventriosum, both elements impart distinct tissue characteristics to the perichondral region. Considering the evolution of osteogenic processes, shark skeletogenesis may illuminate the transition from perichondrium to periosteum, which is a major bone-forming tissue during the process of endochondral ossification. PMID:17451531

  13. Skeletogenesis in the swell shark Cephaloscyllium ventriosum.

    PubMed

    Eames, B Frank; Allen, Nancy; Young, Jonathan; Kaplan, Angelo; Helms, Jill A; Schneider, Richard A

    2007-05-01

    Extant chondrichthyans possess a predominantly cartilaginous skeleton, even though primitive chondrichthyans produced bone. To gain insights into this peculiar skeletal evolution, and in particular to evaluate the extent to which chondrichthyan skeletogenesis retains features of an osteogenic programme, we performed a histological, histochemical and immunohistochemical analysis of the entire embryonic skeleton during development of the swell shark Cephaloscyllium ventriosum. Specifically, we compared staining properties among various mineralizing tissues, including neural arches of the vertebrae, dermal tissues supporting oral denticles and Meckel's cartilage of the lower jaw. Patterns of mineralization were predicted by spatially restricted alkaline phosphatase activity earlier in development. Regarding evidence for an osteogenic programme in extant sharks, a mineralized tissue in the perichondrium of C. ventriosum neural arches, and to a lesser extent a tissue supporting the oral denticle, displayed numerous properties of bone. Although we uncovered many differences between tissues in Meckel's cartilage and neural arches of C. ventriosum, both elements impart distinct tissue characteristics to the perichondral region. Considering the evolution of osteogenic processes, shark skeletogenesis may illuminate the transition from perichondrium to periosteum, which is a major bone-forming tissue during the process of endochondral ossification.

  14. Development of a brazing process for the production of water- cooled bipolar plates made of chromium-coated metal foils for PEM fuel cells

    NASA Astrophysics Data System (ADS)

    Mueller, M.; Hoehlich, D.; Scharf, I.; Lampke, T.; Hollaender, U.; Maier, H. J.

    2016-03-01

    Beside lithium batteries, PEM fuel cells are the most promising strategy as a power source to achieve the targets for introducing and increasing the usage of electric vehicles. Due to limited space and weight problems, water cooled, metallic bipolar plates in a fuel cell metal stack are preferred in motor vehicles. These plates are stamped metal sheets with a complex structure, interconnected media-tight. To meet the multiple tasks and requirements in use, complex and expensive combinations of materials are currently in use (carbon fiber composites, graphite, gold-plated nickel, stainless and acid resistant steel). The production of such plates is expensive as it is connected with considerable effort or the usage of precious metals. As an alternative, metalloid nitrides (CrN, VN, W2N, etc.) show a high chemical resistance, hardness and a good conductivity. So this material category meets the basic requirements of a top layer. However, the standard methods for their production (PVD, CVD) are expensive and have a slow deposition rate and a lower layer thicknesses. Because of these limitations, a full functionality over the life cycle of a bipolar plate is not guaranteed. The contribution shows the development and quantification of an alternative production process for bipolar plates. The expectation is to get significant advantages from the combination of chromium electrodeposition and thermochemical treatment to form chromium nitrides. Both processes are well researched and suitable for series production. The thermochemical treatment of the chromium layer also enables a process-integrated brazing.

  15. Transport studies in polymer electrolyte fuel cell with porous metallic flow field at ultra high current density

    NASA Astrophysics Data System (ADS)

    Srouji, Abdul-Kader

    Achieving cost reduction for polymer electrolyte fuel cells (PEFC) requires a simultaneous effort in increasing power density while reducing precious metal loading. In PEFCs, the cathode performance is often limiting due to both the slow oxygen reduction reaction (ORR), and mass transport limitation caused by limited oxygen diffusion and liquid water flooding at high current density. This study is motivated by the achievement of ultra-high current density through the elimination of the channel/land (C/L) paradigm in PEFC flow field design. An open metallic element (OME) flow field capable of operating at unprecedented ultra-high current density (3 A/cm2) introduces new advantages and limitations for PEFC operation. The first part of this study compares the OME with a conventional C/L flow field, through performance and electrochemical diagnostic tools such as electrochemical impedance spectroscopy (EIS). The results indicate the uniqueness of the OME's mass transport improvement. No sign of operation limitation due to flooding is noted. The second part specifically examines water management at high current density using the OME flow field. A unique experimental setup is developed to measure steady-state and transient net water drag across the membrane, in order to characterize the fundamental aspects of water transport at high current density with the OME. Instead of flooding, the new limitation is identified to be anode side dry-out of the membrane, caused by electroosmotic drag. The OME improves water removal from the cathode, which immediately improves oxygen transport and performance. However, the low water content in the cathode reduces back diffusion of water to the membrane, and electroosmotic drag dominates at high current density, leading to dry-out. The third part employs the OME flow field as a tool that avoids C/L effects endemic to a typical flow field, in order to study oxygen transport resistance at the catalyst layer of a PEFC. In open literature, a

  16. 15N solid-state nuclear magnetic resonance study of pyrolyzed metal-polyaniline cathode catalysts for oxygen reduction in fuel cells

    NASA Astrophysics Data System (ADS)

    Kuroki, Shigeki; Hosaka, Yo; Yamauchi, Chiharu; Nagata, Shinsuke; Sonoda, Mayu

    2015-09-01

    The oxygen reduction reaction (ORR) activity of pyrolyzed metal-free and metal (Mn, Fe, Co, Ni and Cu)-containing polyaniline (PANI) in polymer electrolyte fuel cell (PEFC) was studied. The metal-free PANI800 shows quite poor ORR catalytic activity, whilst the metal-containing PANIMe800 display a better ORR activity. The 15N CP/MAS NMR spectra of PANINi800 and PANICu800 show one weak peak at 118 ppm and there is no peak observed in PANIFe800, against that of PANI800, PANIMn800, PANICo800 and PANINi800 show two peaks at 273 and 118 ppm assigned to the pyridinic and pyridinium nitrogens. It is because of the paramagnetic effect of metal ions. The 15N spin-echo NMR spectra of PANIMe800 with fast recycle delay show the peaks at 140 and 270 ppm assigned to the graphitic and pyridinic nitrogens, against that of PANI800 shows no peak. The spectra of PANIMn800, PANICo800, PANINi800 and PANICu600 also contain a very broaden peak at 430 ppm assigned to the nitrogen with Fermi-contact effect from metal ions. The spectra of PANIFe800 show some spinning side bands and the average Fe3+-15N distance can be calculated. The some amount of iron ion are relieved and average Fe3+-15N distance increase after acid washing and the ORR activity decreases.

  17. Synthesis-Structure-Performance Correlation for Polyaniline-Me-C Non-Precious Metal Cathode Catalysts for Oxygen Reduction in Fuel Cells

    SciTech Connect

    Wu, Gang; Johnston, Christina; Mack, Nathan; Artyushkova, Kateryna; Ferrandon, Magali; Nelson, Mark; Lezama-pacheco, Juan; Conradson, Steven; More, Karren Leslie; Myers, Deborah; Zelenay, Piotr

    2011-01-01

    In this report, we present the systematic preparation of active and durable non-precious metal catalysts (NPMCs) for the oxygen reduction reaction in polymer electrolyte fuel cells (PEFCs) based on the heat treatment of polyaniline/metal/carbon precursors. Variation of the synthesis steps, heat-treatment temperature, metal loading, and the metal type in the synthesis leads to markedly different catalyst activity, speciation, and morphology. Microscopy studies demonstrate notable differences in the carbon structure as a function of these variables. Balancing the need to increase the catalyst's degree of graphitization through heat treatment versus the excessive loss of surface area that occurs at higher temperatures is a key to preparing an active catalyst. XPS and XAFS spectra are consistent with the presence of Me-N{sub x} structures in both the Co and Fe versions of the catalyst, which are often proposed to be active sites. The average speciation and coordination environment of nitrogen and metal, however, depends greatly on the choice of Co or Fe. Taken together, the data indicate that better control of the metal-catalyzed transformations of the polymer into new graphitized carbon forms in the heat-treatment step will allow for even further improvement of this class of catalysts.

  18. Swelling kinetics of poly(N-isopropylacrylamide) gel.

    PubMed

    Andersson, M; Axelsson, A; Zacchi, G

    1998-01-01

    In many gel applications the swelling and shrinking kinetics are very important, e.g. in controlled/slow release, where the kinetics determined the rate of out-diffusion of the active component, and in gel extraction where the gel is swollen and shrunk several times. In this study swelling kinetics of poly(N-isopropylacrylamide) gel (NiPAAm gel) was determined by monitoring the swelling process using a stereo microscope and a video camera. The swelling of spherical gel bodies could conveniently be studied after a temperature change. The results obtained were treated according to the approach of Tanaka and Fillmore, in which the swelling and shrinking of a gel is described as a motion of the gel network according to the diffusion equation. This was shown to be valid when the temperature changes are kept below the critical point of the gel. However, the model fails to describe the shrinking process when passing from below to above the critical temperature. The collective diffusion coefficient (D), defined as the osmotic bulk modulus divided by the friction factor, was determined by fitting to the experimental data. D was found to increase with temperature according to the Wilke-Chang relation D = 2.0.10(-11) + 7.6.10(-17).T/mu. The results were used to simulate the swelling/shrinking process. The simulations show the importance of having sufficiently small gel bodies to achieve a short swelling time.

  19. Seasonality of Ankle Swelling: Population Symptom Reporting Using Google Trends.

    PubMed

    Liu, Fangwei; Allan, G Michael; Korownyk, Christina; Kolber, Michael; Flook, Nigel; Sternberg, Harvey; Garrison, Scott

    2016-07-01

    In our experience, complaints of ankle swelling are more common in summer, typically from patients with no obvious cardiovascular disease. Surprisingly, this observation has never been reported. To objectively establish this phenomenon, we sought evidence of seasonality in the public's Internet searches for ankle swelling. Our data, obtained from Google Trends, consisted of all related Google searches in the United States from January 4, 2004, to January 26, 2016. Consistent with our expectations and confirmed by similar data for Australia, Internet searches for information on ankle swelling are highly seasonal (highest in midsummer), with seasonality explaining 86% of search volume variability.

  20. Molecular accessibility in solvent swelled coal. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1992-11-01

    To expand the information base on molecular accessibility in solvent swelled coal, Argonne Premium Coal Samples (APCS) were swelled in polar, basic solvents before and after moisture loss and upon air oxidation. So far studies have been reported on the changes in pore size distribution as a function of temperature when polar basic swelling solvents are used. Additional studies employing EPR spin probe techniques performed on the breaking up of the hydrogen bonding between bedding planes were later confirmed by magnetic resonance imaging at Argonne National Lab and the University of Illinois.

  1. Seasonality of Ankle Swelling: Population Symptom Reporting Using Google Trends.

    PubMed

    Liu, Fangwei; Allan, G Michael; Korownyk, Christina; Kolber, Michael; Flook, Nigel; Sternberg, Harvey; Garrison, Scott

    2016-07-01

    In our experience, complaints of ankle swelling are more common in summer, typically from patients with no obvious cardiovascular disease. Surprisingly, this observation has never been reported. To objectively establish this phenomenon, we sought evidence of seasonality in the public's Internet searches for ankle swelling. Our data, obtained from Google Trends, consisted of all related Google searches in the United States from January 4, 2004, to January 26, 2016. Consistent with our expectations and confirmed by similar data for Australia, Internet searches for information on ankle swelling are highly seasonal (highest in midsummer), with seasonality explaining 86% of search volume variability. PMID:27401424

  2. Swelling and Contraction of Phaseolus Hypocotyl Mitochondria 1

    PubMed Central

    Earnshaw, M. J.; Truelove, B.

    1968-01-01

    Isolated Phaseolus mitochondria will swell spontaneously in buffered KCl and contract with an oxidizable substrate or ATP + Mg2+. The conditions under which the mitochondria are swollen affect subsequent contraction, substrate oxidation and ion accumulation, but not their oxidative phosphorylation ability. Bovine serum albumin reduces the rate of swelling and promotes substrate oxidation, contraction and ion accumulation. Swelling of these mitochondria is associated with the release of malic dehydrogenase and a loss of membrane integrity. The beneficial effects of bovine serum albumin in preserving the energy linked functions of Phaseolus mitochondria is discussed. PMID:16656729

  3. Chemical Engineering Division fuel cycle programs. Quarterly progress report, April-June 1979. [Pyrochemical/dry processing; waste encapsulation in metal; transport in geologic media

    SciTech Connect

    Steindler, M.J.; Ader, M.; Barletta, R.E.

    1980-09-01

    For pyrochemical and dry processing materials development included exposure to molten metal and salt of Mo-0.5% Ti-0.07% Ti-0.01% C, Mo-30% W, SiC, Si/sub 2/ON/sub 2/, ZrB/sub 2/-SiC, MgAl/sub 2/O/sub 4/, Al/sub 2/O/sub 3/, AlN, HfB/sub 2/, Y/sub 2/O/sub 3/, BeO, Si/sub 3/N/sub 4/, nickel nitrate-infiltrated W, W-coated Mo, and W-metallized alumina-yttria. Work on Th-U salt transport processing included solubility of Th in liquid Cd, defining the Cd-Th and Cd-Mg-Th phase diagrams, ThO/sub 2/ reduction experiments, and electrolysis of CaO in molten salt. Work on pyrochemical processes and associated hardware for coprocessing U and Pu in spent FBR fuels included a second-generation computer model of the transport process, turntable transport process design, work on the U-Cu-Mg system, and U and Pu distribution coefficients between molten salt and metal. Refractory metal vessels are being service-life tested. The chloride volatility processing of Th-based fuel was evaluated for its proliferation resistance, and a preliminary ternary phase diagram for the Zn-U-Pu system was computed. Material characterization and process analysis were conducted on the Exportable Pyrochemical process (Pyro-Civex process). Literature data on oxidation of fissile metals to oxides were reviewed. Work was done on chemical bases for the reprocessing of actinide oxides in molten salts. Flowsheets are being developed for the processing of fuel in molten tin. Work on encapsulation of solidified radioactive waste in metal matrix included studies of leach rate of crystalline waste materials and of the impact resistance of metal-matrix waste forms. In work on the transport properties of nuclear waste in geologic media, adsorption of Sr on oolitic limestone was studied, as well as the migration of Cs in basalt. Fitting of data on the adsorption of iodate by hematite to a mathematical model was attempted.

  4. Synthesis of alumina powder by the urea-glycine-nitrate combustion process: a mixed fuel approach to nanoscale metal oxides

    NASA Astrophysics Data System (ADS)

    Sharma, Amit; Rani, Amita; Singh, Ajay; Modi, O. P.; Gupta, Gaurav K.

    2014-03-01

    Main objective of present work is to study the efficiency of mixed fuel towards solution combustion synthesis of alumina powder, which otherwise prepared by single fuel and study of properties of final product with mixed fuel approach. Two different fuels, glycine and urea, along with aluminium nitrates have been used to prepare nanophase alumina powder. Different fuel to oxidizer ratios and different percentage combination of two fuels were used to prepare six samples. In all samples, nanoscale particle size obtained. Parameter which continuously changes the results of various characterisations is percentage combination of two fuels. In case where percentage of urea is higher than glycine reaction takes place with high exothermicity and hence crystallinity in product phase, whereas glycine promotes amorphous character. With mixed fuel approach, crystallinity can be enhanced easily, by calcinations of powder product at low temperature, because due to mixed urea and glycine, there is already some fraction of crystallinity observed. Overall mixed fuel approach has ability to produce nanophase alumina powder with wide range of particles size.

  5. Metallized Gelled Propellants: Heat Transfer of a Rocket Engine Fueled by Oxygen/RP-1/Aluminum Was Measured by a Calorimeter

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan A.

    1998-01-01

    A set of analyses was conducted to determine the heat transfer characteristics of metallized gelled liquid propellants in a rocket engine. These analyses used data from experiments conducted with a small 30- to 40-lbf thrust engine composed of a modular injector, igniter, chamber, and nozzle. The fuels used were traditional liquid RP-1 and gelled RP-1 with 0-, 5-, and 55-wt % loadings of aluminum (Al) with gaseous oxygen as the oxidizer. Heat transfer measurements were made with a calorimeter chamber and nozzle setup that had a total of 31 cooling channels. A gelled fuel coating, composed of unburned gelled fuel and partially combusted RP-1, formed in the 0-, 5- and 55-wt % engines. For the 0- and 5-wt % RP-1/Al, the coating caused a large decrease in calorimeter engine heat flux in the last half of the chamber. This heat flux reduction was analyzed by comparing engine firings and the changes in the heat flux during a firing at NASA Lewis Research Center's Rocket Laboratories. This work is part of an ongoing series of analyses of metallized gelled propellants.

  6. MOELCULAR SIZE EXCLUSION BY SOIL ORGANIC MATERIALS ESTIMATED FROM THEIR SWELLING IN ORGANIC SOLVENTS

    EPA Science Inventory

    A published method previously developed to measure the swelling characteristics of pow dered coal samples has been adapted for swelling measurements on various peat, pollen, chain, and cellulose samples The swelling of these macromolecular materials is the volumetric manifestatio...

  7. Design of high density gamma-phase uranium alloys for LEU dispersion fuel applications.

    SciTech Connect

    Hofman, G. L.

    1998-10-19

    Uranium alloys are candidates for the fuel phase in aluminum matrix dispersion fuels requiring high uranium loading. Certain uranium alloys have been shown to have good irradiation performance at intermediate burnup. Previous studies have shown that acceptable fission gas swelling behavior and fuel-aluminum interaction is possible only if the fuel alloy can be maintained in the high temperature body-centered-cubic {gamma}-phase during fabrication and irradiation, i.e., at temperatures at which {alpha}-U is the equilibrium phase. Transition metals in Groups V through VIII are known to allow metastable retention of the gamma phase below the equilibrium isotherm. These metals have varying degrees of effectiveness in stabilizing the gamma phase. Certain alloys are metastable for very long times at the relatively low fuel temperatures seen in research reactor operation. In this paper, the existing data on the gamma stability of binary and ternary uranium alloys is analyzed. The mechanism and kinetics of decomposition of the gamma phase are assessed with the help of metal alloy theory. Alloys with the highest possible uranium content, good gamma-phase stability, and good neutronic performance are identified for further metallurgical studies and irradiation tests. Results from theory will be compared with experimentally generated data.

  8. Swelling-induced and controlled curving in layered gel beams

    PubMed Central

    Lucantonio, A.; Nardinocchi, P.; Pezzulla, M.

    2014-01-01

    We describe swelling-driven curving in originally straight and non-homogeneous beams. We present and verify a structural model of swollen beams, based on a new point of view adopted to describe swelling-induced deformation processes in bilayered gel beams, that is based on the split of the swelling-induced deformation of the beam at equilibrium into two components, both depending on the elastic properties of the gel. The method allows us to: (i) determine beam stretching and curving, once assigned the characteristics of the solvent bath and of the non-homogeneous beam, and (ii) estimate the characteristics of non-homogeneous flat gel beams in such a way as to obtain, under free-swelling conditions, three-dimensional shapes. The study was pursued by means of analytical, semi-analytical and numerical tools; excellent agreement of the outcomes of the different techniques was found, thus confirming the strength of the method. PMID:25383031

  9. Postoperative Submandibular Gland Swelling following Craniotomy under General Anesthesia.

    PubMed

    Nakanishi, Haruka; Tono, Tetsuya; Ibusuki, Shoichiro

    2015-01-01

    Objective. Reporting of a rare case of postoperative submandibular gland swelling following craniotomy. Case Report. A 33-year-old male underwent resection for a brain tumor under general anesthesia. The tumor was resected via a retrosigmoid suboccipital approach and the patient was placed in a lateral position with his face down and turned to the right. Slight swelling of the right submandibular gland was observed just after the surgery. Seven hours after surgery, edematous change around the submandibular gland worsened and he required emergent reintubation due to airway compromise. The cause of submandibular gland swelling seemed to be an obstruction of the salivary duct due to surgical positioning. Conclusion. Once submandibular swelling and edematous change around the submandibular gland occur, they can worsen and compromise the air way within several hours after operation. Adequate precaution must be taken for any predisposing skull-base surgery that requires strong cervical rotation and flexion. PMID:26697254

  10. Postoperative Submandibular Gland Swelling following Craniotomy under General Anesthesia

    PubMed Central

    Nakanishi, Haruka; Tono, Tetsuya; Ibusuki, Shoichiro

    2015-01-01

    Objective. Reporting of a rare case of postoperative submandibular gland swelling following craniotomy. Case Report. A 33-year-old male underwent resection for a brain tumor under general anesthesia. The tumor was resected via a retrosigmoid suboccipital approach and the patient was placed in a lateral position with his face down and turned to the right. Slight swelling of the right submandibular gland was observed just after the surgery. Seven hours after surgery, edematous change around the submandibular gland worsened and he required emergent reintubation due to airway compromise. The cause of submandibular gland swelling seemed to be an obstruction of the salivary duct due to surgical positioning. Conclusion. Once submandibular swelling and edematous change around the submandibular gland occur, they can worsen and compromise the air way within several hours after operation. Adequate precaution must be taken for any predisposing skull-base surgery that requires strong cervical rotation and flexion. PMID:26697254

  11. Apparatus measures swelling of membranes in electrochemical cells

    NASA Technical Reports Server (NTRS)

    Hennigan, T. J.

    1965-01-01

    Apparatus consisting of a pressure plate unit, four springs of known spring constant and a micrometer measures the swelling and force exerted by the polymer membranes of alkaline electrochemical cells.

  12. Status of advanced fuel candidates for Sodium Fast Reactor within the Generation IV International Forum

    SciTech Connect

    F. Delage; J. Carmack; C. B. Lee; T. Mizuno; M. Pelletier; J. Somers

    2013-10-01

    The main challenge for fuels for future Sodium Fast Reactor systems is the development and qualification of a nuclear fuel sub-assembly which meets the Generation IV International Forum goals. The Advanced Fuel project investigates high burn-up minor actinide bearing fuels as well as claddings and wrappers to withstand high neutron doses and temperatures. The R&D outcome of national and collaborative programs has been collected and shared between the AF project members in order to review the capability of sub-assembly material and fuel candidates, to identify the issues and select the viable options. Based on historical experience and knowledge, both oxide and metal fuels emerge as primary options to meet the performance and the reliability goals of Generation IV SFR systems. There is a significant positive experience on carbide fuels but major issues remain to be overcome: strong in-pile swelling, atmosphere required for fabrication as well as Pu and Am losses. The irradiation performance database for nitride fuels is limited with longer term R&D activities still required. The promising core material candidates are Ferritic/Martensitic (F/M) and Oxide Dispersed Strengthened (ODS) steels.

  13. Profile of the non-fuel, non-metal mining industry. EPA Office of Compliance sector notebook project

    SciTech Connect

    1995-09-01

    This profile provides an overview of SIC code 14, which includes mining and quarrying of nonmetallic minerals, except fuels; and establishments engaged primarily in mining or quarrying, developing mines, or exploring for non-fuel, nonmetallic minerals. Also included are certain well and brine operations, and primary preparation plants engaged in crushing, grinding, and washing.

  14. Molecular accessibility in solvent swelled coal. Quarterly report, November 1991

    SciTech Connect

    Kispert, L.D.

    1991-12-31

    The EPR-spin probe method was used to study the swelling of covalently cross-linked 2%, 4%, 6%, 8% and 12% polystyrene-divinyl benzene copolymers, used as models of APCS coal structural elements. The results were compared with swelling studies on APCS coals and confirmed results showing that coal was polymeric, that it had covalent cross-links increasing with rank, that it was structurally anisotropic, and that its swelling was anisotropic. The low temperature swelling of Argonne Premium Coal Samples using solvents of varying polarity was investigated. The variation in the shape of the pore was followed as a function of temperature and swelling solvent polarity. This change in pore structure was attributed to break-up of the hydrogen bonding network in coal by polar solvents. The modification in pore shape from spherical to cylindrical was attributed to anisotropy in hydrogen bond densities. The structural changes in coal pores that occur when APCS coal is dehydrated prior to swelling with polar solvents has been determined. These changes are different from those that occur in the absence of prior dehydration. Most impressive is the huge change that occurs in lignite coal (Beulah-Zap). It appears that this coal has collapsed upon dehydration preventing any spin probe from being trapped in the dehydrated lignite upon swelling. Various sized probes have been studied. A study on the variation in the hydrogen bonding character of the pore wall as the coals are swelled with various polar solvents has also been completed. A statistical analysis of the data has been completed to determine important trends in the data. 9 refs.

  15. Application of Neutron-Absorbing Structural-Amorphous Metal (SAM) Coatings for Spent Nuclear Fuel (SNF) Container to Enhance Criticality Safety Controls

    SciTech Connect

    Choi, J; Lee, C; Day, D; Wall, M; Saw, C; MoberlyChan, W; Farmer, J; Boussoufl, M; Liu, B; Egbert, H; Branagan, D; D'Amato, A

    2006-11-13

    Spent nuclear fuel contains fissionable materials ({sup 235}U, {sup 239}Pu, {sup 241}Pu, etc.). Neutron multiplication and the potential for criticality are enhanced by the presence of a moderator during cask loading in water, water incursion in accidents conditions during spent fuel storage or transport. To prevent nuclear criticality in spent fuel storage, transportation, and during disposal, neutron-absorbing materials (or neutron poisons, such as borated stainless steel, Boral{trademark}, Metamic{trademark}, Ni-Gd, and others) would have to be applied. The success in demonstrating that the High-Performance Corrosion-Resistant material (HPCRM) can be thermally applied as coating onto base metal to provide for corrosion resistance for many naval applications raises the interest in applying the HPCRM to USDOE/OCRWM spent fuel management program. The fact that the HPCRM relies on the high content of boron to make the material amorphous--an essential property for corrosion resistance--and that the boron has to be homogeneously distributed in the HPCRM qualify the material to be a neutron poison.

  16. Swelling of four glove materials challenged by six metalworking fluids.

    PubMed

    Xu, Wenhai; Que Hee, Shane S

    2008-01-01

    The performance of protective gloves against metalworking fluids (MWFs) has rarely been studied because of the difficult chemical analysis associated with complex MWFs. In the present study, glove swelling was used as a screening parameter of glove compatibility after challenge of the outer surfaces of chloroprene, latex, nitrile, and vinyl disposable gloves by six MWF concentrates for 2 hours in an ASTM F-739-type permeation cell without collection medium. Swelling relative to original thickness was up to 39% for latex, 7.6% for chloroprene, and 3.5% for nitrile. Shrinking up to 9.3% occurred for vinyl. Chloroprene and latex did not swell significantly for the semisynthetic and synthetic MWFs. Vinyl, previously not tested, was a good candidate for MWFs other than the soluble oil type. Although nitrile was recommended by the National Institute for the Occupational Safety and Health (NIOSH) for all types of MWFs, its swelling after 2-hour challenge was significant with Student t-tests for the soluble oil, synthetic, and semisynthetic MWFs. Glove swelling can be used as a screening chemical degradation method for mixtures such as MWFs with difficult chemical analysis. Further studies need to be conducted on the relationship between permeation and glove swelling.

  17. Microchannel deformations due to solvent-induced PDMS swelling.

    PubMed

    Dangla, Rémi; Gallaire, François; Baroud, Charles N

    2010-11-01

    The compatibility of polydimethylsiloxane (PDMS) channels with certain solvents is a well known problem of soft lithography techniques, in particular when it leads to the swelling of the PDMS blocks. However, little is known about the modification of microchannel geometries when they are subjected to swelling solvents. Here, we experimentally measure the deformations of the roof of PDMS microchannels due to such solvents. The dynamics of impregnation of the solvents in PDMS and its relation to volume dilation are first addressed in a model experiment, allowing the precise measurement of the diffusion coefficients of oils in PDMS. When Hexadecane, a swelling solvent, fills a microchannel 1 mm in width and 50 μm in height, we measure that the channel roof bends inwards and takes a parabolic shape with a maximum deformation of 7 μm. The amplitude of the subsidence is found to increase with the channel width, reaching 28 μm for a 2 mm wide test section. On the other hand, perfluorinated oils do not swell the PDMS and the microchannel geometry is not affected by the presence of perfluorodecalin. Finally, we observe that the trajectories of droplets flowing in this microchannel are strongly affected by the deformations: drops carried by swelling oils are pushed towards the edges of the channel while those carried by non-swelling oils remain in the channel center. PMID:20848011

  18. Rate dependence of swelling in lithium-ion cells

    SciTech Connect

    Oh, KY; Siegel, JB; Secondo, L; Kim, SU; Samad, NA; Qin, JW; Anderson, D; Garikipati, K; Knobloch, A; Epureanu, BI; Monroe, CW; Stefanopoulou, A

    2014-12-01

    Swelling of a commercial 5 Ah lithium-ion cell with a nickel/manganese/cobalt-oxide cathode is investigated as a function of the charge state and the charge/discharge rate. In combination with sensitive displacement measurements, knowledge of the electrode configuration within this prismatic cell's interior allows macroscopic deformations of the casing to be correlated to electrochemical and mechanical transformations in individual anode/separator/cathode layers. Thermal expansion and interior charge state are both found to cause significant swelling. At low rates, where thermal expansion is negligible, the electrode sandwich dilates by as much as 1.5% as the charge state swings from 0% to 100% because of lithium-ion intercalation. At high rates a comparably large residual swelling was observed at the end of discharge. Thermal expansion caused by joule heating at high discharge rate results in battery swelling. The changes in displacement with respect to capacity at low rate correlate well with the potential changes known to accompany phase transitions in the electrode materials. Although the potential response changes minimally with the C-rate, the extent of swelling varies significantly, suggesting that measurements of swelling may provide a sensitive gauge for characterizing dynamic operating states. (C) 2014 Elsevier B.V. All rights reserved.

  19. Swelling of four glove materials challenged by six metalworking fluids.

    PubMed

    Xu, Wenhai; Que Hee, Shane S

    2008-01-01

    The performance of protective gloves against metalworking fluids (MWFs) has rarely been studied because of the difficult chemical analysis associated with complex MWFs. In the present study, glove swelling was used as a screening parameter of glove compatibility after challenge of the outer surfaces of chloroprene, latex, nitrile, and vinyl disposable gloves by six MWF concentrates for 2 hours in an ASTM F-739-type permeation cell without collection medium. Swelling relative to original thickness was up to 39% for latex, 7.6% for chloroprene, and 3.5% for nitrile. Shrinking up to 9.3% occurred for vinyl. Chloroprene and latex did not swell significantly for the semisynthetic and synthetic MWFs. Vinyl, previously not tested, was a good candidate for MWFs other than the soluble oil type. Although nitrile was recommended by the National Institute for the Occupational Safety and Health (NIOSH) for all types of MWFs, its swelling after 2-hour challenge was significant with Student t-tests for the soluble oil, synthetic, and semisynthetic MWFs. Glove swelling can be used as a screening chemical degradation method for mixtures such as MWFs with difficult chemical analysis. Further studies need to be conducted on the relationship between permeation and glove swelling. PMID:17680173

  20. Compliant fuel cell system

    DOEpatents

    Bourgeois, Richard Scott; Gudlavalleti, Sauri

    2009-12-15

    A fuel cell assembly comprising at least one metallic component, at least one ceramic component and a structure disposed between the metallic component and the ceramic component. The structure is configured to have a lower stiffness compared to at least one of the metallic component and the ceramic component, to accommodate a difference in strain between the metallic component and the ceramic component of the fuel cell assembly.

  1. [Reduction of postoperative swelling. Objective measurement of swelling of the upper ankle joint in treatment with serrapeptase-- a prospective study].

    PubMed

    Esch, P M; Gerngross, H; Fabian, A

    1989-02-10

    Using a quantitative standardized procedure, the swelling of the ankle produced by supination trauma was measured. In the 66 patients with fresh rupture of the lateral ligament treated surgically at our Department between December 1986 and April 1987, a prospective study of the effect of serrapeptase (Aniflazym) on post-operative swelling and pain was carried out in 3 randomized groups of patients. In the group receiving the test substance, the swelling had decreased by 50% on the third post-operative day, while in the other two control groups (elevation of the leg, bed rest, with and without the application of ice) no reduction in swelling had occurred at that time. The difference is statistically significant (p = 0.013). Decreasing pain correlated for the most part with the reduction in swelling. Thus, the patients receiving the test substance more rapidly became pain-free than did the control groups. On the basis of these results, serrapeptase would appear to be an effective preparation for the post-operative reduction of swelling, in comparison with the classical conservative measures, for example, the application of ice.

  2. Neutronic fuel element fabrication

    DOEpatents

    Korton, George

    2004-02-24

    This disclosure describes a method for metallurgically bonding a complete leak-tight enclosure to a matrix-type fuel element penetrated longitudinally by a multiplicity of coolant channels. Coolant tubes containing solid filler pins are disposed in the coolant channels. A leak-tight metal enclosure is then formed about the entire assembly of fuel matrix, coolant tubes and pins. The completely enclosed and sealed assembly is exposed to a high temperature and pressure gas environment to effect a metallurgical bond between all contacting surfaces therein. The ends of the assembly are then machined away to expose the pin ends which are chemically leached from the coolant tubes to leave the coolant tubes with internal coolant passageways. The invention described herein was made in the course of, or under, a contract with the U.S. Atomic Energy Commission. It relates generally to fuel elements for neutronic reactors and more particularly to a method for providing a leak-tight metal enclosure for a high-performance matrix-type fuel element penetrated longitudinally by a multiplicity of coolant tubes. The planned utilization of nuclear energy in high-performance, compact-propulsion and mobile power-generation systems has necessitated the development of fuel elements capable of operating at high power densities. High power densities in turn require fuel elements having high thermal conductivities and good fuel retention capabilities at high temperatures. A metal clad fuel element containing a ceramic phase of fuel intimately mixed with and bonded to a continuous refractory metal matrix has been found to satisfy the above requirements. Metal coolant tubes penetrate the matrix to afford internal cooling to the fuel element while providing positive fuel retention and containment of fission products generated within the fuel matrix. Metal header plates are bonded to the coolant tubes at each end of the fuel element and a metal cladding or can completes the fuel-matrix enclosure

  3. Evaluation of nickel-titanium oxide-niobium pentoxide metal ceramic composite as interconnect for solid oxide fuel cell

    NASA Astrophysics Data System (ADS)

    Budur, Abhijith

    With increasing importance for clean energy, fuel cells have gained great significance in recent decades. Solid oxide fuel cells are easy to transport due to presence of solid electrolyte and also have requisite electrical properties,but have been obstructed by their limitation to be used at only temperatures greater than 6000C and less than 8000C. To construct a stack of cells, materials that are good electrical conductors and having necessary mechanical strengths at that temperatures are being considered as interconnects between the cells. Evaluation of Nickel-Titanium dioxide-Niobium pentoxide (NTN) as interconnect and comparison to Stainless Steel 441 alloy has been made in this research. The criteria for evaluation are the resistance, long-term stability and the power density characteristics of the cell for each interconnect. Electrical measurements by impedance spectroscopy techniques were conducted at variousworking temperatures using a gas mixture of 10 % hydrogen and 90% nitrogen to evaluate both interconnect materials in the working range of fuel cells. Scanning Electron Microscopy images of Lanthanum Strontium Manganite paste before and after the fuel cell measurements are shown.The results showed that both NTN and Stainless Steel 441 interconnects exhibit similar electrical properties under operating conditions of the fuel cell. Since theNTN interconnect is less prone to corrosion and does not have the effect of chromium poisoning, it can be considered as a viable interconnect material for solid oxide fuel cells.

  4. Coupled thermo-hydro-chemical models of swelling bentonites

    NASA Astrophysics Data System (ADS)

    Samper, Javier; Mon, Alba; Zheng, Liange; Montenegro, Luis; Naves, Acacia; Pisani, Bruno

    2014-05-01

    The disposal of radioactive waste in deep geological repositories is based on the multibarrier concept of retention of the waste by a combination of engineered and geological barriers. The engineered barrier system (EBS) includes the solid conditioned waste-form, the waste container, the buffer made of materials such as clay, grout or crushed rock that separate the waste package from the host rock and the tunnel linings and supports. The geological barrier supports the engineered system and provides stability over the long term during which time radioactive decay reduces the levels of radioactivity. The strong interplays among thermal (T), hydrodynamic (H), mechanical (M) and chemical (C) processes during the hydration, thermal and solute transport stages of the engineered barrier system (EBS) of a radioactive waste repository call for coupled THMC models for the metallic overpack, the unsaturated compacted bentonite and the concrete liner. Conceptual and numerical coupled THMC models of the EBS have been developed, which have been implemented in INVERSE-FADES-CORE. Chemical reactions are coupled to the hydrodynamic processes through chemical osmosis (C-H coupling) while bentonite swelling affects solute transport via changes in bentonite porosity changes (M-H coupling). Here we present THMC models of heating and hydration laboratory experiments performed by CIEMAT (Madrid, Spain) on compacted FEBEX bentonite and numerical models for the long-term evolution of the EBS for 1 Ma. The changes in porosity caused by swelling are more important than those produced by the chemical reactions during the early evolution of the EBS (t < 100 years). For longer times, however, the changes in porosity induced by the dissolution/precipitation reactions are more relevant due to: 1) The effect of iron mineral phases (corrosion products) released by the corrosion of the carbon steel canister; and 2) The hyper alkaline plume produced by the concrete liner. Numerical results show that

  5. Molecular accessibility in solvent swelled coals. Final report

    SciTech Connect

    Kispert, L.D.

    1994-04-01

    The conversion of coal by an economically feasible catalytic method requires the catalyst to diffuse into the coal sample so that hydrogenation catalysis can occur from within as well as the normal surface catalysis. Thus an estimate of the size, shape, and reactivity, of the pores in the coal before and after the swelling with different solvents is needed so that an optimum sized catalyst will be used. This study characterizes the accessible area found in Argonne Premium Coal Samples (APCS) using a EPR spin probe technique. The properties deduced in this manner correlate well with the findings deduced from SANS, NMR, SEM, SAXS and light scattering measurements. The use of nitroxide spin probes with swelling solvents is a simple way in which to gain an understanding of the pore structure of coals, how it changes in the presence of swelling solvents and the chemistry that occurs at the pore wall. Hydrogen bonding sites occur primarily in low-rank coals and vary in reactive strength as rank is varied. Unswelled coals contain small, spherical pores which disappear when coal is swelled in the presence of polar solvents. Swelling studies of polystyrene-divinyl benzene copolymers implied that coal is polymeric, contains significant quantities of covalent cross-links and the covalent cross-link density increases with rank.

  6. Experimental investigations of heat transfer and temperature fields in models simulating fuel assemblies used in the core of a nuclear reactor with a liquid heavy-metal coolant

    NASA Astrophysics Data System (ADS)

    Belyaev, I. A.; Genin, L. G.; Krylov, S. G.; Novikov, A. O.; Razuvanov, N. G.; Sviridov, V. G.

    2015-09-01

    The aim of this experimental investigation is to obtain information on the temperature fields and heat transfer coefficients during flow of liquid-metal coolant in models simulating an elementary cell in the core of a liquid heavy metal cooled fast-neutron reactor. Two design versions for spacing fuel rods in the reactor core were considered. In the first version, the fuel rods were spaced apart from one another using helical wire wound on the fuel rod external surface, and in the second version spacer grids were used for the same purpose. The experiments were carried out on the mercury loop available at the Moscow Power Engineering Institute National Research University's Chair of Engineering Thermal Physics. Two experimental sections simulating an elementary cell for each of the fuel rod spacing versions were fabricated. The temperature fields were investigated using a dedicated hinged probe that allows temperature to be measured at any point of the studied channel cross section. The heat-transfer coefficients were determined using the wall temperature values obtained at the moment when the probe thermocouple tail end touched the channel wall. Such method of determining the wall temperature makes it possible to alleviate errors that are unavoidable in case of measuring the wall temperature using thermocouples placed in slots milled in the wall. In carrying out the experiments, an automated system of scientific research was applied, which allows a large body of data to be obtained within a short period of time. The experimental investigations in the first test section were carried out at Re = 8700, and in the second one, at five values of Reynolds number. Information about temperature fields was obtained by statistically processing the array of sampled probe thermocouple indications at 300 points in the experimental channel cross section. Reach material has been obtained for verifying the codes used for calculating velocity and temperature fields in channels with

  7. Swelling equilibria for temperature-sensitive ampholytic hydrogels

    SciTech Connect

    Baker, J.P.; Stephens, D.R.; Blanch, H.W.; Prausnitz, J.M.

    1992-09-01

    Temperature-sensitive N-isopropylacrylamide (NIPA)-based ampho-lytic hydrogels were synthesized by copolymerizing NIPA with the cationic monomer methacrylamidopropyl trimethylammonium chloride (MAPTAC) and the anionic monomer sodium styrene sulfonate (SSS). The total nominal charge density of the hydrogels was held constant at 8 mol % (dry basis), while the molar ratio of anionic to cationic moieties within the hydrogels was varied. Swelling equilibria were measured in water at 6C, and in aqueous sodium chloride solutions ranging in concentration from 10{sup {minus}5}to 5 M and temperature ranging from 6 to 56C. Consistent with expectations, the swelling behavior of the hydrogels was found to be controlled by temperature at low salt concentrations; as the sodium chloride concentration increased, temperature control of hydrogel swelling decreased. Slight antipolyelectrolyte behavior was observed for the hydrogel prepared with equal molar amounts of MAPTAC and SSS.

  8. Depleting depletion: Polymer swelling in poor solvent mixtures

    NASA Astrophysics Data System (ADS)

    Mukherji, Debashish; Marques, Carlos; Stuehn, Torsten; Kremer, Kurt

    A polymer collapses in a solvent when the solvent particles dislike monomers more than the repulsion between monomers. This leads to an effective attraction between monomers, also referred to as depletion induced attraction. This attraction is the key factor behind standard polymer collapse in poor solvents. Strikingly, even if a polymer exhibits poor solvent condition in two different solvents, it can also swell in mixtures of these two poor solvents. This collapse-swelling-collapse scenario is displayed by poly(methyl methacrylate) (PMMA) in aqueous alcohol. Using molecular dynamics simulations of a thermodynamically consistent generic model and theoretical arguments, we unveil the microscopic origin of this phenomenon. Our analysis suggests that a subtle interplay of the bulk solution properties and the local depletion forces reduces depletion effects, thus dictating polymer swelling in poor solvent mixtures.

  9. Geoid height versus topography for oceanic plateaus and swells

    NASA Technical Reports Server (NTRS)

    Sandwell, David T.; Mackenzie, Kevin R.

    1989-01-01

    Gridded geoid height data (Marsh et al.l, 1986) and gridded bathymetry data (Van Wykhouse, 1973) are used to estimate the average compensation depths of 53 oceanic swells and plateaus. The relationship between geoid height and topography is examined using Airy and thermal compensation models. It is shown that geoid height is linearly related to topography between wavelengths of 400 and 4000 m as predicted by isostatic compensation models. The geoid/topography ratio is dependent on the average depth of compensation. The intermediate geoid/topography ratios of most thermal swells are interpreted as a linear combination of the decaying thermal swell signature and that of the persisting Airy-compensated volcanic edifice.

  10. Swelling of several commercial alloys following high fluence neutron irradiation

    SciTech Connect

    Powell, R.W.; Peterson, D.T.; Zimmerschied, M.K.; Bates, J.F.

    1981-01-01

    Swelling values have been determined for a set of commercial alloys irradiated to a peak fluence of 17.8 x 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV) over the temperature range of 400 to 650/sup 0/C. The alloys studied fall into three classes: the ferritic alloys AISI 430F, AISI 416, EM-12, H-11 and 2 1/4 Cr-1 Mo; the superalloys Inconel 718 and Inconel X-750; and the refractory alloys TZM and Nb-1 Zr. After irradiation to a peak fluence approaching goal exposures envisioned for advanced fusion reactor first walls, all of the alloys display swelling resistance far superior to cold worked AISI 316. Of the three alloy classes examined the swelling resistance of the ferritics is the least sensitive to composition.

  11. Adsorption and strain: The CO 2-induced swelling of coal

    NASA Astrophysics Data System (ADS)

    Vandamme, M.; Brochard, L.; Lecampion, B.; Coussy, O.

    2010-10-01

    Enhanced coal bed methane recovery (ECBM) consists in injecting carbon dioxide in coal bed methane reservoirs in order to facilitate the recovery of the methane. The injected carbon dioxide gets adsorbed at the surface of the coal pores, which causes the coal to swell. This swelling in confined conditions leads to a closure of the coal reservoir cleat system, which hinders further injection. In this work we provide a comprehensive framework to calculate the macroscopic strains induced by adsorption in a porous medium from the molecular level. Using a thermodynamic approach we extend the realm of poromechanics to surface energy and surface stress. We then focus on how the surface stress is modified by adsorption and on how to estimate adsorption behavior with molecular simulations. The developed framework is here applied to the specific case of the swelling of CO 2-injected coal, although it is relevant to any problem in which adsorption in a porous medium causes strains.

  12. Immobilization of a Metal-Nitrogen-Carbon Catalyst on Activated Carbon with Enhanced Cathode Performance in Microbial Fuel Cells.

    PubMed

    Yang, Wulin; Logan, Bruce E

    2016-08-23

    Applications of microbial fuel cells (MFCs) are limited in part by low power densities mainly due to cathode performance. Successful immobilization of an Fe-N-C co-catalyst on activated carbon (Fe-N-C/AC) improved the oxygen reduction reaction to nearly a four-electron transfer, compared to a twoelectron transfer achieved using AC. With acetate as the fuel, the maximum power density was 4.7±0.2 W m(-2) , which is higher than any previous report for an air-cathode MFC. With domestic wastewater as a fuel, MFCs with the Fe-N-C/AC cathode produced up to 0.8±0.03 W m(-2) , which was twice that obtained with a Pt-catalyzed cathode. The use of this Fe-N-C/AC catalyst can therefore substantially increase power production, and enable broader applications of MFCs for renewable electricity generation using waste materials.

  13. Non-breaking swell dissipation from synthethic aperture radar

    NASA Astrophysics Data System (ADS)

    Stopa, Justin; Husson, Romain; Ardhuin, Fabrice; Collard, Fabrice; Chapron, Bertrand

    2015-04-01

    Swells have the unique ability to propagate away from their generation region with very little attenuation. Only one study exists in the ocean wave literature that measures the decay rate by following a swell with in-situ measurements along its great circle route. More recently used space-borne synthetic aperture radar (SAR) to measure the attenuation. They estimated the dissipation rate from SAR with a limited number of cases: 11 storms with 22 total events. The present work extrapolates their technique to more events since ENVISAT has collected SAR data from 2002-2012. The dissipation rate is then determined in a two step process. First swell sources are identified from density maps of back-propagated waves at their group velocity along great circles. Next a "point-source" model is assumed and the waves from all directions and frequencies are propagated forward to find matching SAR observations. Relatively small directional bins are used to group observations creating transects from a given swell event. This ensemble of tracks is the basic dataset used to calculate a more statistically robust measure of the dissipation rate. Individual tracks and the swell behavior are explored through this dataset. Our results are in agreement with previous findings and it is verified that swells are very persistent with e-folding scales larger than 20,000 km and they behave nonlinearly as a function of wave frequency. The results are discussed in terms of their implications in spectral wave models as well as identify limitations of the remotely sensed wave spectra. The wind's role on the dissipation rate cannot be determined from this analysis stressing the need for concurrent wind and wave observations.

  14. Swelling of cross-linked polystyrene spheres in toluene vapor

    SciTech Connect

    Zhang, R.; Graf, K.; Berger, R.

    2006-11-27

    The swelling behavior of individual micron-sized polystyrene (PS) spheres in toluene vapor was studied via mass loading by means of micromechanical cantilever sensors. For 4%-8% cross-linked PS a mass increase of 180% in saturated toluene vapor was measured. The mass of the swollen PS sphere decreases with increasing exposure time to ultraviolet light. In addition, the swelling response is significantly different between the first and the second exposure to toluene vapor. This is attributed to the formation of a cross-linked shell at the surface of the PS spheres. Shape persistent parts were observed for locally irradiated PS spheres.

  15. Compression and swelling of activated sludge cakes during dewatering.

    PubMed

    Sveegaard, Steffen Gralert; Keiding, Kristian; Christensen, Morten Lykkegaard

    2012-10-15

    A drainage/filtration apparatus was developed for automatically determining sedimentation velocity and dewatering rate. Pressure-step testing was used to study filter cake compressibility, resistance, and swelling. Activated sludge was analysed, and the data indicate that the sludge is highly compressible even at low pressures (10 kPa). Furthermore, compressed sludge cakes swell if the pressure is released. Hence, the average specific cake resistance decreases if the pressure is released, though the resistance is higher after the compression cycle than before. Sludge must be dewatered under low pressure, because higher pressure only compresses the cake and does not improve the dewatering rate.

  16. Prediction of the micro-thermo-mechanical behaviors in dispersion nuclear fuel plates with heterogeneous particle distributions

    NASA Astrophysics Data System (ADS)

    Jiang, Yijie; Wang, Qiming; Cui, Yi; Huo, Yongzhong; Ding, Shurong; Zhang, Lin; Li, Yuanming

    2011-11-01

    Dispersion nuclear fuel elements have promising prospects to be used in advanced nuclear reactors and disposal of nuclear wastes. They consist of fuel meat and cladding, and the fuel meat is a kind of composite fuel in which the fuel particles are embedded in the non-fissile matrix. Prediction of the micro-thermo-mechanical behaviors in dispersion nuclear plates is of importance to their irradiation safety and optimal design. In this study, the heterogeneity of the fuel particles along the thickness direction in the fuel meat is considered. The 3D finite element models have been developed respectively for two cases: (1) variation of fuel particle-particle (PP) distances for the particles near the mid-plane of the fuel meat; (2) variation of the particle-cladding (PC) distances for the fuel particles near the interface between the fuel meat and the cladding. The respective finite strain constitutive relations are developed for the fuel particle, metal matrix and cladding. The developed virtual temperature method is used to simulate irradiation swelling of the fuel particles and irradiation growth of the metal cladding. Effects of the heterogeneous distributions of the fuel particles on the micro temperature fields and the micro stress-strain fields are investigated. The obtained results indicate that: (1) as a whole, the maximum Mises stress, equivalent plastic strain and first principal stress at the matrix between the two closest particles increase with decreasing the particle-particle (PP) distance; existence of large first principal stresses there may be the main factor that induces the matrix failure; (2) variation of the particle-cladding (PC) distance has remarkable effects on the interfacial normal stress and shear stress at the interface between the fuel meat and the cladding; the first principal stress at the cladding near the interface increases dramatically when the fuel particle is closer and closer to the cladding. Thus, the proper distance between the

  17. A review of the stability and durability of non-precious metal catalysts for the oxygen reduction reaction in proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Banham, Dustin; Ye, Siyu; Pei, Katie; Ozaki, Jun-ichi; Kishimoto, Takeaki; Imashiro, Yasuo

    2015-07-01

    A major hurdle to the widespread commercialization of proton exchange membrane fuel cells (PEMFCs) is the high loading of noble metal (Pt/Pt-alloy) catalyst at the cathode, which is necessary to facilitate the inherently sluggish oxygen reduction reaction (ORR). To eliminate the use of Pt/Pt-alloy catalysts at the cathode of PEMFCs and thus significantly reduce the cost, extensive research on non-precious metal catalysts (NPMCs) has been carried out over the past decade. Major advances in improving the ORR activity of NPMCs, particularly Fe- and Co-based NPMCs, have elevated these materials to a level at which they can start to be considered as potential alternatives to Pt/Pt-alloy catalysts. Unfortunately, the stability (performance loss following galvanostatic experiments) of these materials is currently unacceptably low and the durability (performance loss following voltage cycling) remains uncertain. The three primary mechanisms of instability are: (a) Leaching of the metal site, (b) Oxidative attack by H2O2, and (c) Protonation followed by possible anion adsorption of the active site. While (a) has largely been solved, further work is required to understand and prevent losses from (b) and/or (c). Thus, this review is focused on historical progress in (and possible future strategies for) improving the stability/durability of NPMCs.

  18. Oxidation of methanol on 2nd and 3rd row group VIII transition metals (Pt, Ir, Os, Pd, Rh, and Ru): Application to direct methanol fuel cells

    SciTech Connect

    Kua, J.; Goddard, W.A. III

    1999-12-01

    Using first principles quantum mechanics [nonlocal density functional theory (B3LYP)], the authors calculated the 13 most likely intermediate species for methanol oxidation on clusters of all 2nd and 3rd row Group VIII transition metals for all three likely binding sites (top, bridge, and cap). This comprehensive set of binding energies and structures allows a detailed analysis of possible reaction mechanisms and how they change for different metals. This illustrates the role in which modern quantum chemical methods can be used to provide data for combinatorial strategies for discovering and designing new catalysts. Methanol dehydrogenation is most facile on Pt, with the hydrogens preferentially stripped off the carbon end. However, water dehydrogenation is most facile on Ru. These results support the bifunctional mechanism for methanol oxidation on Pt-Ru alloys in direct methanol fuel cells (DMFCs). Pure Os is capable of performing both functionalities without cocatalyst. It is suggested that pure Os be examined as a potential catalyst for low overpotential, highly dispersed catalyst DMFCs. Pathways to form the second C-O bond differ between the pure metals (Pt and Os) in which (CO){sub ads} is probably activated by (OH){sub ads} and the Pt-Ru binary system in which (COH){sub ads} is probably activated by O{sub ads}. For all cases formation of (COOH){sub ads} is an important precursor to the final dehydrogenation to desorb CO{sub 2} from the surface.

  19. Protected Nuclear Fuel Element

    DOEpatents

    Kittel, J. H.; Schumar, J. F.

    1962-12-01

    A stainless steel-clad actinide metal fuel rod for use in fast reactors is reported. In order to prevert cladding failures due to alloy formation between the actinide metal and the stainless steel, a mesh-like sleeve of expanded metal is interposed between them, the sleeve metal being of niobium, tantalum, molybdenum, tungsten, zirconium, or vanadium. Liquid alkali metal is added as a heat transfer agent. (AEC)

  20. Advanced liquefaction using coal swelling and catalyst dispersion techniques. Volume 2, appendices. Final technical report, October 1, 1991--September 30, 1994

    SciTech Connect

    Curtis, C.W.; Chander, S.; Gutterman, C.

    1995-04-01

    Liquefaction experiments were undertaken using subbituminous Black Thunder mine coal to observe the effects of aqueous SO{sub 2} coal beneficiation and the introduction of various coal swelling solvents and catalyst precursors. Aqueous SO{sub 2} beneficiation of Black Thunder coal removed alkali metals and alkaline earth metals, increased the sulfur content and increased the catalytic liquefaction conversion to THF solubles compared to untreated Black Thunder coal. The liquefaction solvent had varying effects on coal conversion, depending upon the type of solvent added. The hydrogen donor solvent, dihydroanthracene, was most effective, while a coal-derived Wilsonville solvent promoted more coal conversion than did relatively inert 1-methylnaphthalene. Swelling of coal with hydrogen bonding solvents tetrahydrofuran (THF), isopropanol, and methanol, prior to reaction resulted in increased noncatalytic conversion of both untreated and SO{sub 2} treated Black Thunder coals, while dimethylsulfoxide (DMSO), which was absorbed more into the coal than any other swelling solvent, was detrimental to coal conversion. Swelling of SO{sub 2} treated coal before liquefaction resulted in the highest coal conversions; however, the untreated coal showed the most improvements in catalytic reactions when swelled in either THF, isopropanol, or methanol prior to liquefaction. The aprotic solvent DMSO was detrimental to coal conversion.

  1. Experimental study and modeling of swelling and bubble growth in carbon nanofiber filled mesophase pitch during carbonization

    NASA Astrophysics Data System (ADS)

    Calebrese, Christopher

    Graphite and all carbon bipolar plates show corrosion resistance in fuel cells and provide good electrical conductivity. These materials typically need to be individually machined, a time consuming and costly process. Mesophase pitch is used to manufacture carbon fibers and carbon-carbon composites. This material provides a good starting point for the production of a moldable, all carbon bipolar plate. However, processing of mesophase pitch to produce all carbon materials requires a time intensive oxidation step to prevent swelling during carbonization. In this work, carbon nanofibers were used to reduce swelling in mesophase pitch. It was found that the increase in viscosity with the addition of carbon nanofibers was responsible for the reduction in swelling. The influence of the filler became apparent above the percolation threshold. At loadings below the percolation threshold, the swelling of the mesophase pitch was not reduced after carbonization. The swelling of the mesophase pitch at a given carbon nanofiber loading was also dependent on the length of the carbon nanofibers. Longer carbon nanofibers led to greater increases in the viscosity of the melt and thus led to greater reduction in swelling. The final carbon product was evaluated for use as a low temperature fuel cell bipolar plate material. Constraining the mesophase pitch during carbonization led to a final product with strength and electrical conductivity comparable to current composite bipolar plate materials. The addition of micron size chopped glass fibers with a softening point near 850°C and carbon nanofibers led to a final product with air permeability less than that of graphite. A spherically symmetric, single bubble growth model was also developed. The model included temperature dependence, liquid to bubble mass transfer and reactions in the system. Results from simulations showed that that the increase in viscosity due to the addition of carbon nanofibers slows the growth of bubbles, but

  2. Fuel flexible fuel injector

    DOEpatents

    Tuthill, Richard S; Davis, Dustin W; Dai, Zhongtao

    2015-02-03

    A disclosed fuel injector provides mixing of fuel with airflow by surrounding a swirled fuel flow with first and second swirled airflows that ensures mixing prior to or upon entering the combustion chamber. Fuel tubes produce a central fuel flow along with a central airflow through a plurality of openings to generate the high velocity fuel/air mixture along the axis of the fuel injector in addition to the swirled fuel/air mixture.

  3. Enhancing the use of waste activated sludge as bio-fuel through selectively reducing its heavy metal content.

    PubMed

    Dewil, Raf; Baeyens, Jan; Appels, Lise

    2007-06-18

    Power plant or cement kiln co-incineration are important disposal routes for the large amounts of waste activated sludge (WAS) which are generated annually. The presence of significant amounts of heavy metals in the sludge however poses serious problems since they are partly emitted with the flue gases (and collected in the flue gas dedusting) and partly incorporated in the ashes of the incinerator: in both cases, the disposal or reuse of the fly ash and bottom ashes can be jeopardized since subsequent leaching in landfill disposal can occur, or their "pozzolanic" incorporation in cement cannot be applied. The present paper studies some physicochemical methods for reducing the heavy metal content of WAS. The used techniques include acid and alkaline thermal hydrolysis and Fenton's peroxidation. By degrading the extracellular polymeric substances, binding sites for a large amount of heavy metals, the latter are released into the sludge water. The behaviour of several heavy metals (Cd, Cr, Cu, Hg, Pb, Ni, Zn) was assessed in laboratory tests. Results of these show a significant reduction of most heavy metals.

  4. How does a flexible chain of active particles swell?

    PubMed

    Kaiser, Andreas; Babel, Sonja; ten Hagen, Borge; von Ferber, Christian; Löwen, Hartmut

    2015-03-28

    We study the swelling of a flexible linear chain composed of active particles by analytical theory and computer simulation. Three different situations are considered: a free chain, a chain confined to an external harmonic trap, and a chain dragged at one end. First, we consider an ideal chain with harmonic springs and no excluded volume between the monomers. The Rouse model of polymers is generalized to the case of self-propelled monomers and solved analytically. The swelling, as characterized by the spatial extension of the chain, scales with the monomer number defining a Flory exponent ν which is ν = 1/2, 0, 1 in the three different situations. As a result, we find that activity does not change the Flory exponent but affects the prefactor of the scaling law. This can be quantitatively understood by mapping the system onto an equilibrium chain with a higher effective temperature such that the chain swells under an increase of the self-propulsion strength. We then use computer simulations to study the effect of self-avoidance on active polymer swelling. In the three different situations, the Flory exponent is now ν = 3/4, 1/4, 1 and again unchanged under self-propulsion. However, the chain extension behaves non-monotonic in the self-propulsion strength.

  5. Swelling and drug release from oral thin films (OTFs)

    NASA Astrophysics Data System (ADS)

    Adrover, A.; Casadei, M. A.; Paolicelli, P.; Petralito, S.; Varani, G.

    2016-05-01

    We investigate the characteristic time-scales for swelling and drug release from polymeric thin films for buccal delivery. In this work, novel OTFs were prepared combining Gellan gum, a natural polysaccharide well known in the pharmaceutical field, along with Glycerol, used as plasticizer. A new millifluidic flow-through device is adopted for in-vitro release tests.

  6. Linear Viscoelasticity and Swelling of Polyelectrolyte Complex Coacervates

    NASA Astrophysics Data System (ADS)

    Hamad, Fawzi; Colby, Ralph

    2012-02-01

    The addition of near equimolar amounts of poly(diallyldimethylammonium chloride) to poly(isobutylene-alt-maleate sodium), results in formation of a polyelectrolyte complex coacervate. Zeta-potential titrations conclude that these PE-complexes are nearly charge-neutral. Swelling and rheological properties are studied at different salt concentrations in the surrounding solution. The enhanced swelling observed at high salt concentration suggests the system behaves like a polyampholyte gel, and weaker swelling at very low salt concentrations implies polyelectrolyte gel behavior. Linear viscoelastic oscillatory shear measurements indicate that the coacervates are viscoelastic liquids and that increasing ionic strength of the medium weakens the electrostatic interactions between charged units, lowering the relaxation time and viscosity. We use the time-salt superposition idea recently proposed by Spruijt, et al., allowing us to construct master curves for these soft materials. Similar swelling properties observed when varying molecular weights. Rheological measurements reveal that PE-complexes with increasing molecular weight polyelectrolytes form a network with higher crosslink density, suggesting time-molecular weight superposition idea.

  7. Impedimetric transduction of swelling in pH-responsive hydrogels.

    PubMed

    Mac Kenna, Nicky; Calvert, Paul; Morrin, Aoife

    2015-05-01

    A pH-responsive hydrogel composed of an aliphatic diamine cross-linked with polyethylene glycol diglycidyl ether (PEGDGE) using a single, rapid polymerisation step has been used to detect glucose by entrapping glucose oxidase (GOx) within its cationic network. The swelling response of hydrogel disks on exposure to glucose were optimised through variation of factors including the cross-linking density of the network, GOx loading and the addition of catalase. Hydrogel-modified carbon cloth electrodes were also prepared and characterised using voltammetric and impedimetric techniques. Non-faradaic electrochemical impedance spectroscopy (EIS) and gravimetry were both employed to track the swelling response of the gels quantitatively. The clear potential of utilising impedance to transduce hydrogel swelling was demonstrated where a linear decrease in gel resistance (Rgel) corresponding to the swelling response was observed in the range 1 to 100 μM. A dramatic increase in the limit of detection of six orders of magnitude over the gravimetric measurement was achieved (from 0.33 mM to 0.08 μM). This increased sensitivity, coupled with the textile-based electrode substrate approach opens the potential applicability of this system for monitoring glucose concentration via the skin by sweat or interstitial fluid (ISF). PMID:25768307

  8. Impedimetric transduction of swelling in pH-responsive hydrogels.

    PubMed

    Mac Kenna, Nicky; Calvert, Paul; Morrin, Aoife

    2015-05-01

    A pH-responsive hydrogel composed of an aliphatic diamine cross-linked with polyethylene glycol diglycidyl ether (PEGDGE) using a single, rapid polymerisation step has been used to detect glucose by entrapping glucose oxidase (GOx) within its cationic network. The swelling response of hydrogel disks on exposure to glucose were optimised through variation of factors including the cross-linking density of the network, GOx loading and the addition of catalase. Hydrogel-modified carbon cloth electrodes were also prepared and characterised using voltammetric and impedimetric techniques. Non-faradaic electrochemical impedance spectroscopy (EIS) and gravimetry were both employed to track the swelling response of the gels quantitatively. The clear potential of utilising impedance to transduce hydrogel swelling was demonstrated where a linear decrease in gel resistance (Rgel) corresponding to the swelling response was observed in the range 1 to 100 μM. A dramatic increase in the limit of detection of six orders of magnitude over the gravimetric measurement was achieved (from 0.33 mM to 0.08 μM). This increased sensitivity, coupled with the textile-based electrode substrate approach opens the potential applicability of this system for monitoring glucose concentration via the skin by sweat or interstitial fluid (ISF).

  9. Shrink-swell behavior of soil across a vertisol catena

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shrinking and swelling of soils and the associated formation and closing of cracks can vary spatially within the smallest hydrologic unit subdivision utilized in surface hydrology models. Usually in the application of surface hydrology models, cracking is not considered to vary within a hydrologic u...

  10. A 47-year-old man with tongue swelling.

    PubMed

    Rodríguez-Roa, Maristely; Nazario, Sylvette; Ramos, Cristina

    2016-07-01

    Intermittent tongue angioedema can be the initial presentation of several disorders including angiotensin-converting-enzyme inhibitor induced angioedema and hereditary angioedema. Persistent angioedema on the other hand, can be associated with amyloidosis, tumors, thyroid disorders and acromegaly. We present a case of intermittent episodes of tongue swelling progressing to macroglossia. PMID:27401321

  11. Lupus erythematosus--a case of facial swelling.

    PubMed

    Loescher, A; Edmondson, H D

    1988-04-01

    A case is reported of acute facial swelling following tooth extraction that failed to respond in a normal manner. The patient developed systemic signs and symptoms ultimately revealing the diagnosis of lupus erythematosus. The possibility of soft tissue lesions arising in some forms of lupus is emphasised by this report. PMID:3163493

  12. The Swelling and Destabilization of a Coronal Mass Ejection (abstract)

    NASA Technical Reports Server (NTRS)

    Martin, S. F.; Feynman, J.

    1993-01-01

    We will present and discuss data for a bugle that was particularly well observed. Apparently the swelling of the bugle and its destabilization were caused by the newly emerging flux and its interaction with the pre-existing active regions and coronal structures.

  13. Demonstration of Solvent Differences by Visible Polymer Swelling.

    ERIC Educational Resources Information Center

    Ross, Joseph H.

    1983-01-01

    Effect of the "polarity" of low-polarity solvents on the amount of swelling produced in a solid polymer (demonstrated in an organic chemistry lecture) is also suitable as a laboratory experiment. Students can be assigned to a small group of solvents from the list provided. Procedures and materials needed are included. (Author/JN)

  14. Urethroscrotal Fistula: A Rare Cause of Scrotal Swelling

    PubMed Central

    Parlak, Selcuk; Okay, Aysun E.

    2016-01-01

    Summary Background Urethroscrotal fistula (USF) is an abnormal communication between the urethra and the scrotum. This rare abnormality may be iatrogenic or secondary to perforation of the urethra by a stone. After the passage of urine to the scrotum through the fistula, painless scrotal swelling develops, which disappears completely with manual compression, and voiding can be maintained in this way. Retrograde urethrography (RU) and voiding cystourethrography (VCU) are traditional diagnostic methods, but they have limitations, such as technical difficulties and inability to evaluate the surrounding tissues. Multidetector CT (MDCT), together with reformatted images, can provide valuable information about the surrounding tissues and associated pathologies. Case Report We present a case of a 36-year-old male patient who had painless scrotal swelling after cystolithotomy and urethral stone surgery. The patient indicated that the swelling disappeared after manual compression. A fistula between the bulbous urethra and the scrotum was discovered by MDCT. In our case, we believe that the fistula developed iatrogenically during stone excision or secondary to perforation of the urethra by a stone. Conclusions As a rare pathology, urethroscrotal fistula should be considered in men with a history of urethral stone surgery and symptoms, including painless scrotal swelling, which can be manually compressed after voiding.

  15. [A former bodybuilder with a swelling on the forearm].

    PubMed

    Strijbos, Ruben M; Zwaard, Ton M

    2015-01-01

    A 56-year-old man came to the general practitioner with a solitary compressible swelling on his left forearm, which enlarged during exercise. The patient reported a history of bodybuilding and he worked as a plasterer. Physical examination revealed primary varicose of the upper extremity, a rare localisation of a common vascular disease.

  16. Urethroscrotal Fistula: A Rare Cause of Scrotal Swelling

    PubMed Central

    Parlak, Selcuk; Okay, Aysun E.

    2016-01-01

    Summary Background Urethroscrotal fistula (USF) is an abnormal communication between the urethra and the scrotum. This rare abnormality may be iatrogenic or secondary to perforation of the urethra by a stone. After the passage of urine to the scrotum through the fistula, painless scrotal swelling develops, which disappears completely with manual compression, and voiding can be maintained in this way. Retrograde urethrography (RU) and voiding cystourethrography (VCU) are traditional diagnostic methods, but they have limitations, such as technical difficulties and inability to evaluate the surrounding tissues. Multidetector CT (MDCT), together with reformatted images, can provide valuable information about the surrounding tissues and associated pathologies. Case Report We present a case of a 36-year-old male patient who had painless scrotal swelling after cystolithotomy and urethral stone surgery. The patient indicated that the swelling disappeared after manual compression. A fistula between the bulbous urethra and the scrotum was discovered by MDCT. In our case, we believe that the fistula developed iatrogenically during stone excision or secondary to perforation of the urethra by a stone. Conclusions As a rare pathology, urethroscrotal fistula should be considered in men with a history of urethral stone surgery and symptoms, including painless scrotal swelling, which can be manually compressed after voiding. PMID:27668028

  17. Anomalous swelling behavior of FM 5055 carbon phenolic composite

    NASA Technical Reports Server (NTRS)

    Stokes, E. H.

    1992-01-01

    The swelling response of a typical carbon phenolic composite was measured in the three primary material directions. The data obtained sugrest that at low and high relative humidities the incremental increase in moisture absorption can be attributed primarily to the resin. At intermediate relative humidities, the water is moving largely into the carbonized fibers.

  18. Advanced liquefaction using coal swelling and catalyst dispersion techniques

    SciTech Connect

    Curtis, C.W. ); Gutterman, C. ); Chander, S. )

    1992-08-26

    Research in this project centers upon developing a new approach to the direct liquefaction of coal to produce an all-distillate product slate at a sizable cost reduction over current technology. The approach integrates all aspects of the coal liquefaction process including coal selection, pretreatment, coal swelling with catalyst impregnation, coal liquefaction experimentation, product recovery with characterization, alternate bottoms processing, and a technical assessment including an economic evaluation. The project is being carried out under contract to the United States Department of Energy. On May 28, 1992, the Department of Energy authorized starting the experimental aspects of this projects; therefore, experimentation at Amoco started late in this quarterly report period. Research contracts with Auburn University, Pennsylvania State University, and Foster Wheeler Development Corporation were signed during June, 1992, so their work was just getting underway. Their work will be summarized in future quarterly reports. A set of coal samples were sent to Hazen Research for beneficiation. The samples were received and have been analyzed. The literature search covering coal swelling has been up-dated, and preliminary coal swelling experiments were carried out. Further swelling experimentation is underway. An up-date of the literature on the liquefaction of coal using dispersed catalysts is nearing completion; it will be included in the next quarterly report.

  19. Case of a non-pulsatile groin swelling.

    PubMed

    Razif, M A Mohamed; Rajasingam, V; Abdullah, B J J

    2002-12-01

    We report a case of a non-pulsatile groin swelling in a 38 years old male drug addict without the typical clinical signs of an aneurysm. Ultrasound revealed a left femoral artery pseudo-aneurysm. He was surgically treated and the vessels were ligated without revascularisation.

  20. Micro fuel cell

    SciTech Connect

    Zook, L.A.; Vanderborgh, N.E.; Hockaday, R.

    1998-12-31

    An ambient temperature, liquid feed, direct methanol fuel cell device is under development. A metal barrier layer was used to block methanol crossover from the anode to the cathode side while still allowing for the transport of protons from the anode to the cathode. A direct methanol fuel cell (DMFC) is an electrochemical engine that converts chemical energy into clean electrical power by the direct oxidation of methanol at the fuel cell anode. This direct use of a liquid fuel eliminates the need for a reformer to convert the fuel to hydrogen before it is fed into the fuel cell.