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Sample records for bed high temperature

  1. Graphite beds for coolant filtration at high temperature

    International Nuclear Information System (INIS)

    Heathcock, R.E.; Lacy, C.S.

    1978-01-01

    High temperature filtration will be provided for new Ontario Hydro CANDU heat transport systems. Filtration has been shown to effectively reduce the concentration of circulating corrosion products in our heat transport systems, hence, minimizing the processes of activity transport. This paper will present one option we have for this application; Deep Bed Granular Graphite Filters. The filter system is described by discussing pertinent aspects of its development programme. The compatibility of the filter and the heat transport coolant are demonstrated by results from loop tests, both out- and in-reactor, and by subsequent results from a large filter installation in the NPD NGS heat transport system. (author)

  2. Transmutation of plutonium in pebble bed type high temperature reactors

    International Nuclear Information System (INIS)

    Bende, E.E.

    1997-01-01

    The pebble bed type High Temperature Reactor (HTR) has been studied as a uranium-free burner of reactor grade plutonium. In a parametric study, the plutonium loading per pebble as well as the type and size of the coated particles (CPs) have been varied to determine the plutonium consumption, the final plutonium burnup, the k ∞ and the temperature coefficients as a function of burnup. The plutonium loading per pebble is bounded between 1 and 3 gr Pu per pebble. The upper limit is imposed by the maximal allowable fast fluence for the CPs. A higher plutonium loading requires a longer irradiation time to reach a desired burnup, so that the CPs are exposed to a higher fast fluence. The lower limit is determined by the temperature coefficients, which become less negative with increasing moderator-actinide ratio. A burnup of about 600 MWd/kgHM can be reached. With the HTR's high efficiency of 40%, a plutonium supply of 1520 kg/GW e a is achieved. The discharges of plutonium and minor actinides are then 450 and 110 kg/GW e a, respectively. (author)

  3. Experimental investigation of thermal de-stratification in rock bed TES systems for high temperature applications

    International Nuclear Information System (INIS)

    Okello, Denis; Nydal, Ole J.; Banda, Eldad J.K.

    2014-01-01

    Highlights: • High thermal stratifications exists rock bed TES when charge with high temperature heat. • Faster thermal degradation occurs in highly stratified bed irrespective of the bed length. • Average rate of heat loss as a function of storage time increases with increasing average bed temperature. - Abstract: Solar energy fluctuates so much that it cannot promote continuous use. Integration of Thermal Energy Storage (TES) with solar energy collection devices has the potential of making solar energy available on demand. Thermal energy can be stored in a bed of rocks at temperatures suitable for applications like cooking, boiling space heating, etc. During charging, temperature stratification is observed in the bed. In a stratified system, if the heat is used immediately, then it is possible to extract heat at reasonably high temperature from the top. For cases where the system is to be used after sometime (later at night or the following morning), the high temperature heat at the top is observed to degrade as the system tries to establish thermal equilibrium irrespective of the bed height. The average rate of heat loss from the TES unit to the ambient is found to increase with increasing average bed temperatures

  4. The effects of temperatures on the pebble flow in a pebble bed high temperature reactor

    International Nuclear Information System (INIS)

    Sen, R. S.; Cogliati, J. J.; Gougar, H. D.

    2012-01-01

    The core of a pebble bed high temperature reactor (PBHTR) moves during operation, a feature which leads to better fuel economy (online refueling with no burnable poisons) and lower fuel stress. The pebbles are loaded at the top and trickle to the bottom of the core after which the burnup of each is measured. The pebbles that are not fully burned are recirculated through the core until the target burnup is achieved. The flow pattern of the pebbles through the core is of importance for core simulations because it couples the burnup distribution to the core temperature and power profiles, especially in cores with two or more radial burnup 'zones '. The pebble velocity profile is a strong function of the core geometry and the friction between the pebbles and the surrounding structures (other pebbles or graphite reflector blocks). The friction coefficient for graphite in a helium environment is inversely related to the temperature. The Thorium High Temperature Reactor (THTR) operated in Germany between 1983 and 1989. It featured a two-zone core, an inner core (IC) and outer core (OC), with different fuel mixtures loaded in each zone. The rate at which the IC was refueled relative to the OC in THTR was designed to be 0.56. During its operation, however, this ratio was measured to be 0.76, suggesting the pebbles in the inner core traveled faster than expected. It has been postulated that the positive feedback effect between inner core temperature, burnup, and pebble flow was underestimated in THTR. Because of the power shape, the center of the core in a typical cylindrical PBHTR operates at a higher temperature than the region next to the side reflector. The friction between pebbles in the IC is lower than that in the OC, perhaps causing a higher relative flow rate and lower average burnup, which in turn yield a higher local power density. Furthermore, the pebbles in the center region have higher velocities than the pebbles next to the side reflector due to the

  5. The effects of temperatures on the pebble flow in a pebble bed high temperature reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sen, R. S.; Cogliati, J. J.; Gougar, H. D. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415 (United States)

    2012-07-01

    The core of a pebble bed high temperature reactor (PBHTR) moves during operation, a feature which leads to better fuel economy (online refueling with no burnable poisons) and lower fuel stress. The pebbles are loaded at the top and trickle to the bottom of the core after which the burnup of each is measured. The pebbles that are not fully burned are recirculated through the core until the target burnup is achieved. The flow pattern of the pebbles through the core is of importance for core simulations because it couples the burnup distribution to the core temperature and power profiles, especially in cores with two or more radial burnup 'zones '. The pebble velocity profile is a strong function of the core geometry and the friction between the pebbles and the surrounding structures (other pebbles or graphite reflector blocks). The friction coefficient for graphite in a helium environment is inversely related to the temperature. The Thorium High Temperature Reactor (THTR) operated in Germany between 1983 and 1989. It featured a two-zone core, an inner core (IC) and outer core (OC), with different fuel mixtures loaded in each zone. The rate at which the IC was refueled relative to the OC in THTR was designed to be 0.56. During its operation, however, this ratio was measured to be 0.76, suggesting the pebbles in the inner core traveled faster than expected. It has been postulated that the positive feedback effect between inner core temperature, burnup, and pebble flow was underestimated in THTR. Because of the power shape, the center of the core in a typical cylindrical PBHTR operates at a higher temperature than the region next to the side reflector. The friction between pebbles in the IC is lower than that in the OC, perhaps causing a higher relative flow rate and lower average burnup, which in turn yield a higher local power density. Furthermore, the pebbles in the center region have higher velocities than the pebbles next to the side reflector due to the

  6. Discussion on Design Transients of Pebble-bed High Temperature Gas-cooled Reactor

    International Nuclear Information System (INIS)

    Wang Yan; Li Fu; Zheng Yanhua

    2014-01-01

    In order to assure high quality for the components and their supports in the reactor coolant system, etc., some thermal-hydraulic transient conditions will be selected and researched for equipment design evaluation to satisfy the requirements ASME code, which are based on the conservative estimates of the magnitude and frequency of the temperature and pressure transients resulting from various operating conditions in the plant. In the mature design on pressurized water reactor, five conditions are considered. For the developing advanced pebble-bed high temperature gas-cooled reactor(HTGR), its design and operation has much difference with other reactors, so the transients of the pebble-bed high temperature gas-cooled reactor have distinctive characteristics. In this paper, the possible design transients of the pebble-bed HTGR will be discussed, and the frequency of design transients for equipment fatigue analysis and stress analysis due to cyclic stresses is also studied. The results will provide support for the design and construct of the pebble-bed HTGR. (author)

  7. Analysis of impact of mixing flow on the pebble bed high temperature reactor

    International Nuclear Information System (INIS)

    Hao Chen; Li Fu; Guo Jiong

    2014-01-01

    The impact of the mixing flow in the pebble flow on pebble bed high temperature gas cooled reactor (HTR) was analyzed in the paper. New code package MFVSOP which can simulate the mixing flow was developed. The equilibrium core of HTR-PM was selected as reference case, the impact of the mixing flow on the core parameters such as core power peak factor, power distribution was analyzed with different degree of mixing flow, and uncertainty analysis was carried out. Numerical results showed that the mixing flow had little impact on key parameters of pebble bed HTR, and the multiple-pass-operation-mode in pebble bed HTR can reduce the uncertainty arouse from the mixing flow. (authors)

  8. Consideration of emergency source terms for pebble-bed high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Tao, Liu; Jun, Zhao; Jiejuan, Tong; Jianzhu, Cao

    2009-01-01

    Being the last barrier in the nuclear power plant defense-in-depth strategy, emergency planning (EP) is an integrated project. One of the key elements in this process is emergency source terms selection. Emergency Source terms for light water reactor (LWR) nuclear power plant (NPP) have been introduced in many technical documents, and advanced NPP emergency planning is attracting attention recently. Commercial practices of advanced NPP are undergoing in the world, pebble-bed high-temperature gas-cooled reactor (HTGR) power plant is under construction in China which is considered as a representative of advanced NPP. The paper tries to find some pieces of suggestion from our investigation. The discussion of advanced NPP EP will be summarized first, and then the characteristics of pebble-bed HTGR relating to EP will be described. Finally, PSA insights on emergency source terms selection and current pebble-bed HTGR emergency source terms suggestions are proposed

  9. Probabilistic safety assessment framework of pebble-bed modular high-temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Liu Tao; Tong Jiejuan; Zhao Jun; Cao Jianzhu; Zhang Liguo

    2009-01-01

    After an investigation of similar reactor type probabilistic safety assessment (PSA) framework, Pebble-bed Modular High-Temperature Gas-cooled Reactor (HTR-PM) PSA framework was presented in correlate with its own design characteristics. That is an integral framework which spreads through event sequence structure with initiating events at the beginning and source term categories in the end. The analysis shows that it is HTR-PM design feature that determines its PSA framework. (authors)

  10. Predicting freeboard heat transfer by using empirical correlations in high temperature fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Biyikli, Suleyman [Okan University Tuzla Kampusu, Faculty of Engineering and Architecture (Turkey)], email: suleyman.biyikli@okan.edu.tr

    2011-07-01

    This article investigates the heat transfer characteristics for horizontal tubes in a freeboard region of high temperature fluidized beds. The freeboard entrainment heights are calculated by using empirical correlations described in detail and used in estimating the heat transfer coefficients from a horizontal tube occurring by radiation, gas convection, and particle contact mechanisms in high temperature a fluidized bed combustor. The total average of these coefficients around a horizontal tube carrying water in high temperature fluidized beds can be written as the sum of convective, radiative, and fluidized-particle contact heat transfer coefficients and these correlations are tested against certain published experimental measurements. In full agreement with this data, it was observed that the calculated heat transfer coefficients increased with increasing gas velocity at a given tube elevation and they decreased and approached the values of single-phase gas convection and radiation with increasing tube elevation in the freeboard region while the relative contribution of radiation increases and approaches a constant fraction of total heat transfer.

  11. Stability analysis of the high temperature thermal pebble bed nuclear reactor concept

    International Nuclear Information System (INIS)

    Vondy, D.R.

    1981-02-01

    A study was made of the stability of the high temperature gas-cooled pebble bed core against xenon-driven oscillation. This generic study indicated that a core as large as 3000 MW(t) could be stable. Several aspects present a challenge to analysis including the void space above the pebble bed, the effects of possible control rod configurations, and the temperature feedback contribution. Special methods of analysis were developed in this effort. Of considerable utility was the scheme of including an azimuthal buckling loss term in the neturon balance equations admitting direct solution of the first azimuthal harmonic for a core having azimuthal symmetry. This technique allows the linear stability analysis to be done solving two-dimensional (RZ) problems instead of three-dimensional problems. A scheme for removing the fundamental source contribution was also implemented to allow direct iteration toward the dominant harmonic solution, treating up to three dimensions with diffusion theory

  12. INTENSIFICATION OF HEAT TRANSFER IN A HIGH-TEMPERATURED FLUIDIZED BED

    Directory of Open Access Journals (Sweden)

    А. O. Redko

    2017-10-01

    Full Text Available Purpose. This paper highlights experimental research of heat exchange in coarse particles to ensure the performance of ecological characteristics of Heat supply system. Methodology. The test stand has been developed to solve the defined task. It helps to do the research at the temperature of fluidizing bed and pulsating fluidizing bed at the range 800–1000°С. The temperature of the fluidized bed was provided by burning natural gas and wood waste. Sand and chamotte with a particle size of 1.0 to 5.0 mm were used as the layer material. The heat-transfer coefficient from the layer to the surface, immersed in the layer, and the density of the heat flux were measured by a calorimetric method under steady-state conditions. Smooth tubes and transversely finned with different height and rib spacing were investigated. Experiments in a high-temperature pulsating fluidized bed were carried out with pulsating combustion of natural gas in a layer or in a sublattice chamber into which natural gas and air were separately supplied. The frequency of combustion pulsations was provided by the automation system. The flash frequency was regulated in the range from 0.14 to 5 Hz. Findings. It is presented the results of physical modeling to find out the heat-transfer coefficients of smooth and finned tubes in fluidizing bed of coarse particles in the process of wood waste and gaseous fuel combusting. It is proved that the coefficient of heat transfer increases with increasing temperature by 2–2,5 times in the bed which contains particles diameter of 2.5–5 mm is 300–350Vt/(m2 К that is much higher than for layer furnaces. The results of the experiments are presented in the form of a generalized relationship that takes into account the diameter of the particles and the value of the finning coefficient. Heat transfer of finned tubes is 15–20% less then smooth tubes but the density of heat flow referred to the area of a finned tube is 0,12–0,20 МVt/m2 that

  13. High temperature degradation by erosion-corrosion in bubbling fluidized bed combustors

    Directory of Open Access Journals (Sweden)

    Hou Peggy

    2004-01-01

    Full Text Available Heat-exchanger tubes in fluidized bed combustors (FBCs often suffer material loss due to combined corrosion and erosion. Most severe damage is believed to be caused by the impact of dense packets of bed material on the lower parts of the tubes. In order to understand this phenomenon, a unique laboratory test rig at Berkeley was designed to simulate the particle hammering interactions between in-bed particles and tubes in bubbling fluidized bed combustors. In this design, a rod shaped specimen is actuated a short distance within a partially fluidized bed. The downward specimen motion is controlled to produce similar frequencies, velocities and impact forces as those experienced by the impacting particle aggregates in practical systems. Room temperature studies have shown that the degradation mechanism is a three-body abrasion process. This paper describes the characteristics of this test rig, reviews results at elevated temperatures and compares them to field experience. At higher temperatures, deposits of the bed material on tube surfaces can act as a protective layer. The deposition depended strongly on the type of bed material, the degree of tube surface oxidation and the tube and bed temperatures. With HCl present in the bed, wastage was increased due to enhanced oxidation and reduced oxide scale adherence.

  14. Measurement of flow field in the pebble bed type high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Lee, Sa Ya; Lee, Jae Young

    2008-01-01

    In this study, flow field measurement of the Pebble Bed Reactor(PBR) for the High Temperature Gascooled Reactor(HTGR) was performed. Large number of pebbles in the core of PBR provides complicated flow channel. Due to the complicated geometries, numerical analysis has been intensively made rather than experimental observation. However, the justification of computational simulation by the experimental study is crucial to develop solid analysis of design method. In the present study, a wind tunnel installed with pebbles stacked was constructed and equipped with the Particle Image Velocimetry(PIV). We designed the system scaled up to realize the room temperature condition according to the similarity. The PIV observation gave us stagnation points, low speed region so that the suspected high temperature region can be identified. With the further supplementary experimental works, the present system may produce valuable data to justify the Computational Fluid Dynamics(CFD) simulation method

  15. Renewable side reflector structure for a pebble bed high temperature reactor

    International Nuclear Information System (INIS)

    Martin, Roger.

    1977-01-01

    The description is given of a renewable side reflector structure for a pebble bed high temperature reactor of the kind comprising a cylindrical graphite vessel constituting the neutron reflector, this vessel being filled with graphite pebbles containing the nuclear fuel and enclosed in a concrete protective containment. The internal peripheral area of the vessel is constituted by a line of adjacent graphite rods mounted so that they can rotate about their longitudinal axis and manoeuvrable from outside the concrete containment by means of a shaft passing into it [fr

  16. High temperature CO2 capture using calcium oxide sorbent in a fixed-bed reactor

    International Nuclear Information System (INIS)

    Dou Binlin; Song Yongchen; Liu Yingguang; Feng Cong

    2010-01-01

    The gas-solid reaction and breakthrough curve of CO 2 capture using calcium oxide sorbent at high temperature in a fixed-bed reactor are of great importance, and being influenced by a number of factors makes the characterization and prediction of these a difficult problem. In this study, the operating parameters on reaction between solid sorbent and CO 2 gas at high temperature were investigated. The results of the breakthrough curves showed that calcium oxide sorbent in the fixed-bed reactor was capable of reducing the CO 2 level to near zero level with the steam of 10 vol%, and the sorbent in CaO mixed with MgO of 40 wt% had extremely low capacity for CO 2 capture at 550 deg. C. Calcium oxide sorbent after reaction can be easily regenerated at 900 deg. C by pure N 2 flow. The experimental data were analyzed by shrinking core model, and the results showed reaction rates of both fresh and regeneration sorbents with CO 2 were controlled by a combination of the surface chemical reaction and diffusion of product layer.

  17. Global scaling analysis for the pebble bed advanced high temperature reactor

    International Nuclear Information System (INIS)

    Blandford, E.D.; Peterson, P.F.

    2009-01-01

    Scaled Integral Effects Test (IET) facilities play a critical role in the design certification process of innovative reactor designs. Best-estimate system analysis codes, which minimize deliberate conservatism, require confirmatory data during the validation process to ensure an acceptable level of accuracy as defined by the regulator. The modular Pebble Bed Advanced High Temperature Reactor (PB-AHTR), with a nominal power output of 900 MWth, is the most recent UC Berkeley design for a liquid fluoride salt cooled, solid fuel reactor. The PB-AHTR takes advantage of technologies developed for gas-cooled high temperature thermal and fast reactors, sodium fast reactors, and molten salt reactors. In this paper, non-dimensional scaling groups and similarity criteria are presented at the global system level for a loss of forced circulation transient, where single-phase natural circulation is the primary mechanism for decay heat removal following a primary pump trip. Due to very large margin to fuel damage temperatures, the peak metal temperature of primary-loop components was identified as the key safety parameter of interest. Fractional Scaling Analysis (FSA) methods were used to quantify the intensity of each transfer process during the transient and subsequently rank them by their relative importance while identifying key sources of distortion between the prototype and model. The results show that the development of a scaling hierarchy at the global system level informs the bottom-up scaling analysis. (author)

  18. Development and testing of nuclear graphite for the German pebble-bed high temperature reactor

    International Nuclear Information System (INIS)

    Haag, G.; Delle, W.; Nickel, H.; Theymann, W.; Wilhelmi, G.

    1987-01-01

    Several types of high temperature reactors have been developed in the Federal Republic of Germany. They are all based on spherical fuel elements being surrounded by graphite as reflector material. As an example, HTR-500 developed by the Hochtemperatur Reaktorbau GmbH is shown. The core consists of the top reflector, the side reflector with inner and outer parts, the bottom reflector and the core support columns. The most serious problem with respect to fast neutron radiation damage had to be solved for the materials of those parts near the pebble bed. Regarding the temperature profile in the core, the top reflector is at 300 deg C, and as cooling gas flows from the top downward, the temperature of the inner side reflector rises to about 700 deg C at the bottom. Fortunately, the highest fast neutron load accumulated during the life time of a reactor corresponds to the lowest temperature. This makes graphite components easier to survive neutron exposure without being mechanically damaged, although the maximum fast neutron fluence is as high as 4 x 10 22 /cm 2 at about 400 deg C. HTR graphite components are divided into four classes according to loading. The raw materials for nuclear graphite, the development of pitch coke nuclear graphite, the irradiation behavior of ATR-2E and ASR-IRS and others are reported. (Kako, I.)

  19. Feasibility of Thorium Fuel Cycles in a Very High Temperature Pebble-Bed Hybrid System

    Directory of Open Access Journals (Sweden)

    L.P. Rodriguez

    2015-08-01

    Full Text Available Nuclear energy presents key challenges to be successful as a sustainable energy source. Currently, the viability of the use thorium-based fuel cycles in an innovative nuclear energy generation system is being investigated in order to solve these key challenges. In this work, the feasibility of three thorium-based fuel cycles (232Th-233U, 232Th-239Pu, and 232Th-U in a hybrid system formed by a Very High Temperature Pebble-Bed Reactor (VHTR and two Pebble-Bed Accelerator Driven Systems (ADSs was evaluated using parameters related to the neutronic behavior such as nuclear fuel breeding, minor actinide stockpile, the energetic contribution of each fissile isotope, and the radiotoxicity of the long lived wastes. These parameters were used to compare the fuel cycles using the well-known MCNPX ver. 2.6e computational code. The results obtained confirm that the 232Th-233U fuel cycle is the best cycle for minimizing the production of plutonium isotopes and minor actinides. Moreover, the inclusion of the second stage in the ADSs demonstrated the possibility of extending the burnup cycle duration and reducing the radiotoxicity of the discharged fuel from the VHTR.

  20. Plutonium burning in a pebble-bed type high temperature nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bende, E.E

    2000-01-24

    This thesis deals with the pebble-bed High Temperature Reactor that is fuelled with pure reactor-grade plutonium. It is stressed that neither burnable poisons nor fertile materials like 238U and 212Th are present in the calculational models throughout this thesis. Chapter 2 discusses the general properties of the pebble-bed HTR: the passive safety features of this reactor; different fuel scenarios according to which the pebble-bed HTR can be operated; properties of the pebbles and the coated particles (CPs), including a concise overview of the mechanisms that can lead to coated particle failure. Special attention is paid to the effect of Pu as fuel inside these CPs thereby aiming to indicate which mechanisms are of concern when such CPs are considered as fuel in future reactors. In the last part of this chapter constraints are listed that were imposed to the models considered in the framework of this thesis. Chapter 3 presents the results of unit-cell calculations performed with three code systems. The main objective of this chapter is to compare the calculational results of one particular code system, which is a candidate for the generation of cross sections for a full-core calculation, to those of the other two code systems. Also some reactor physics interpretations of the calculational results are presented. The unit-cell calculations embrace the computation of a number of reactor physics parameters for pebbles with a varying plutonium mass per pebble and with different types of coated particles. For one pebble configuration, these parameters have been calculated for various fuel temperatures and over-all (uniform) temperatures. For that particular pebble configuration, also the results of a two burnup calculations were compared. Chapter 4 reports the results of a parameter study in which the number of coated particles per pebble as well as the type and size of the CPs have been varied. The effect of different pebble configurations on several reactor physics

  1. 3D DEM simulation and analysis of void fraction distribution in a pebble bed high temperature reactor

    International Nuclear Information System (INIS)

    Yang, Xingtuan; Gui, Nan; Tu, Jiyuan; Jiang, Shengyao

    2014-01-01

    Highlights: • We show a detailed analysis of void fraction (VF) in HTR-10 of China using DEM. • Radial distribution (RD) of VF is uniform in the core and oscillated near the wall. • Axial distribution (AD) is linearly varied along height due to effect of gravity. • Steady RD of VF in the conical base is Gaussian-like, larger than packing bed. • Joint linear and normal distribution of VF is analyzed and explained. - Abstract: The current work analyzes the radial and axial distributions of void fraction of a pebble bed high temperature reactor. A three-dimensional pebble bed corresponding to our test facility of pebble bed type gas-cooled high temperature reactor (HTR-10) in Tsinghua University is simulated via discrete element method, and the radial and axial void fraction profiles are calculated. It validates the oscillating characteristics of radial void fraction near the wall. Detailed calculations show the differences of void fraction profiles between the stationary packing bed and the dynamically discharging bed. Based on the vertically and circumferentially averaged radial distribution and horizontally averaged axial distribution of void fraction, a fully three-dimensional analytical distribution of void fraction throughout the bed is established. The results show the combined effects of gravity and void variation in the pebble bed caused by the pebble discharging. It indicates the linearly increased packing effect caused by gravity in the vertical (axial) direction and the normal distribution of void in the horizontal (radial) direction by pebble drainage. These two effects coexist in the conical base of the bed whereas only the former effect exists in the cylindrical volume of the bed

  2. Flow distribution of pebble bed high temperature gas cooled reactors using large eddy simulation

    International Nuclear Information System (INIS)

    Gokhan Yesilyurt; Hassan, Y.A.

    2003-01-01

    A High Temperature Gas-cooled Reactor (HTGR) is one of the renewed reactor designs to play a role in nuclear power generation. This reactor design concepts is currently under consideration and development worldwide. Since the HTGR concept offers inherent safety, has a very flexible fuel cycle with capability to achieve high burnup levels, and provides good thermal efficiency of power plant, it can be considered for further development and improvement as a reactor concept of generation IV. The combination of coated particle fuel, inert helium gas as coolant and graphite moderated reactor makes it possible to operate at high temperature yielding a high efficiency. In this study the simulation of turbulent transport for the gas through the gaps of the spherical fuel elements (fuel pebbles) will be performed. This will help in understanding the highly three-dimensional, complex flow phenomena in pebble bed caused by flow curvature. Under these conditions, heat transfer in both laminar and turbulent flows varies noticeably around curved surfaces. Curved flows would be present in the presence of contiguous curved surfaces. In the case of a laminar flow and of an appreciable effect of thermogravitional forces, the Nusselt (Nu) number depends significantly on the curvature shape of the surface. It changes with order of 10 times. The flow passages through the gap between the fuel balls have concave and convex configurations. Here the action of the centrifugal forces manifests itself differently on convex and concave parts of the flow path (suppression or stimulation of turbulence). The flow of this type has distinctive features. In such flow there is a pressure gradient, which strongly affects the boundary layer behavior. The transition from a laminar to turbulent flow around this curved flow occurs at deferent Reynolds (Re) numbers. Consequently, noncircular curved flows as in the pebble-bed situation, in detailed local sense, is interesting to be investigated. To the

  3. Preliminary Safeguards Assessment for the Pebble-Bed Fluoride High-Temperature Reactor (PB-FHR) Concept

    Energy Technology Data Exchange (ETDEWEB)

    Disser, Jay; Arthur, Edward; Lambert, Janine

    2016-09-01

    This report examines a preliminary design for a pebble bed fluoride salt-cooled high temperature reactor (PB-FHR) concept, assessing it from an international safeguards perspective. Safeguards features are defined, in a preliminary fashion, and suggestions are made for addressing further nuclear materials accountancy needs.

  4. Sustainability of thorium-uranium in pebble-bed fluoride salt-cooled high temperature reactor

    International Nuclear Information System (INIS)

    Zhu, G.; Zou, Y.; Xu, H.

    2016-01-01

    Sustainability of thorium fuel in a Pebble-Bed Fluoride salt-cooled High temperature Reactor (PBFHR) is investigated to find the feasible region of high discharge burnup and negative Flibe (2LiF-BeF_2) salt Temperature Reactivity Coefficient (TRC). Dispersion fuel or pellet fuel with SiC cladding and SiC matrix is used to replace the tri-structural-isotropic (TRISO) coated particle system for increasing fuel loading and decreasing excessive moderation. To analyze the neutronic characteristics, an equilibrium calculation method of thorium fuel self-sustainability is developed. We have compared two refueling schemes (mixing flow pattern and directional flow pattern) and two kinds of reflector materials (SiC and graphite). This method found that the feasible region of breeding and negative Flibe TRC is between 20 vol% and 62 vol% fuel loading in the fuel. A discharge burnup could be achieved up to about 200 MWd/kgHM. The case with directional flow pattern and SiC reflector showed superior burnup characteristics but the worst radial power peak factor, while the case with mixing flow pattern and SiC reflector, which was the best tradeoff between discharge burnup and radial power peak factor, could provide burnup of 140 MWd/kgHM and about 1.4 radial power peak factor with 50 vol% dispersion fuel. In addition, Flibe salt displays good neutron properties as a coolant of quasi-fast reactors due to the strong "9Be(n,2n) reaction and low neutron absorption of "6Li (even at 1000 ppm) in fast spectrum. Preliminary thermal hydraulic calculation shows a good safety margin. The greatest challenge of this reactor may be the decades irradiation time of the pebble fuel. (A.C)

  5. Characteristic behaviour of Pebble Bed High Temperature Gas-cooled Reactors during water ingress events

    International Nuclear Information System (INIS)

    Khoza, Samukelisiwe N.; Serfontein, Dawid E.; Reitsma, Frederik

    2014-01-01

    The presence of water on the tube-side of the steam generators in high temperature gas-cooled reactors (HTGRs) with indirect cycle layouts presents a possibility for a penetration of neutron moderating steam into the core, which may cause a power excursion. This article presents results on the effect of water ingress into the core of the two South African Pebble Bed Modular Reactor design concepts, i.e. the PBMR-200 MW th and the PBMR-400 MW th developed by PBMR SOC Ltd. The VSOP 99/05 suite of codes was used for the simulation of this event. Partial steam vapour pressures were added in stages into the primary circuit in order to investigate the effect of water ingress on reactivity, power profiles and thermal neutron flux profiles. The effects of water ingress into the core are explained by increased neutron moderation, due to the addition of 1 H, which leads to a decrease in resonance capture by 238 U and therefore an increase in the multiplication factor. The more effective moderation of neutrons by definition reduces the fast neutron flux and increases the thermal flux in the core, i.e. leads to a softer spectrum. The more effective moderation also increases the average increase in lethargy between collisions of a neutron with successive fuel kernels, which reduces the probability for neutron capture in the radiative capture resonances of 238 U. The resulting higher resonance escape probability also increases the thermal flux in the core. The softening of the neutron spectrum leads to an increased effective microscopic fission cross section in the fissile isotopes and thus to increased neutron absorption for fission, which reduces the remaining number of neutrons that can diffuse into the reflectors. Therefore water ingress into the core leads to a reduced thermal neutron flux in the reflectors. The power density spatial distribution behaved similarly to the thermal neutron flux in the core. Analysis of possible mechanisms was conducted. The results show that

  6. Porous structure analysis of large-scale randomly packed pebble bed in high temperature gas-cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Cheng; Yang, Xingtuan; Liu, Zhiyong; Sun, Yanfei; Jiang, Shengyao [Tsinghua Univ., Beijing (China). Key Laboratory of Advanced Reactor Engineering and Safety; Li, Congxin [Ministry of Environmental Protection of the People' s Republic of China, Beijing (China). Nuclear and Radiation Safety Center

    2015-02-15

    A three-dimensional pebble bed corresponding to the randomly packed bed in the heat transfer test facility built for the High Temperature Reactor Pebble bed Modules (HTR-PM) in Shandong Shidaowan is simulated via discrete element method. Based on the simulation, we make a detailed analysis on the packing structure of the pebble bed from several aspects, such as transverse section image, longitudinal section image, radial and axial porosity distributions, two-dimensional porosity distribution and coordination number distribution. The calculation results show that radial distribution of porosity is uniform in the center and oscillates near the wall; axial distribution of porosity oscillates near the bottom and linearly varies along height due to effect of gravity; the average coordination number is about seven and equals to the maximum coordination number frequency. The fully established three-dimensional packing structure analysis of the pebble bed in this work is of fundamental significance to understand the flow and heat transfer characteristics throughout the pebble-bed type structure.

  7. Numerical investigation of the flow at the pebble bed of the high temperature gas cooled reactors

    International Nuclear Information System (INIS)

    Costa, Franklin C.; Navarro, Moyses A.; Santos, Andre A.C.

    2011-01-01

    This paper presents a numerical investigation of the thermal and fluid dynamics among the fuel spheres and the cooling fluid, appearing in the core of pebble bed reactor (PBR-Peeble Bed Reactor) using the CFD-Computational Fluid Dynamics CFX 13.0. The paper presents the two analysis results. In the first phase it was considered two heat transfer models for the fuel spheres. In a model it was established volumetric load generation, with thermal conduction for both the fuel and coating. The other model prescribes a heat flux at the sphere surfaces. In this analysis, it was proceed two simulation in the two sphere arrangements, one considering the spheres in contact, and the other with 2 mm spacing between them. At the second analysis it was evaluated the sphere arrangement influence on the thermal and fluid dynamic behavior of the bed. The four simulations present differences in the flow and in the surface and maximum temperature profiles of the coating.(author)

  8. Comparative evaluation of pebble-bed and prismatic fueled high-temperature gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.; Bartine, D.E.

    1981-01-01

    A comparative evaluation has been performed of the HTGR and the Federal Republic of Germany's Pebble Bed Reactor (PBR) for potential commercial applications in the US. The evaluation considered two reactor sizes (1000 and 3000 MW(t)) and three process applications (steam cycle, direct cycle, and process heat, with outlet coolant temperatures of 750, 850, and 950/sup 0/C, respectively). The primary criterion for the comparison was the levelized (15-year) cost of producing electricity or process heat. Emphasis was placed on the cost impact of differences between the prismatic-type HTGR core, which requires periodic refuelings during reactor shutdowns, and the pebble bed PBR core, which is refueled continuously during reactor operations. Detailed studies of key technical issues using reference HTGR and PBR designs revealed that two cost components contributing to the levelized power costs are higher for the PBR: capital costs and operation and maintenance costs. A third cost component, associated with nonavailability penalties, tended to be higher for the PBR except for the process heat application, for which there is a large uncertainty in the HTGR nonavailability penalty at the 950/sup 0/C outlet coolant temperature. A fourth cost component, fuel cycle costs, is lower for the PBR, but not sufficiently lower to offset the capital cost component. Thus the HTGR appears to be slightly superior to the PBR in economic performance. Because of the advanced development of the HTGR concept, large HTGRs could also be commercialized in the US with lower R and D costs and shorter lead times than could large PBRs. It is recommended that the US gas-cooled thermal reactor program continue giving primary support to the HTGR, while also maintaining its cooperative PBR program with FRG.

  9. Comparative evaluation of pebble-bed and prismatic fueled high-temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Kasten, P.R.; Bartine, D.E.

    1981-01-01

    A comparative evaluation has been performed of the HTGR and the Federal Republic of Germany's Pebble Bed Reactor (PBR) for potential commercial applications in the US. The evaluation considered two reactor sizes [1000 and 3000 MW(t)] and three process applications (steam cycle, direct cycle, and process heat, with outlet coolant temperatures of 750, 850, and 950 0 C, respectively). The primary criterion for the comparison was the levelized (15-year) cost of producing electricity or process heat. Emphasis was placed on the cost impact of differences between the prismatic-type HTGR core, which requires periodic refuelings during reactor shutdowns, and the pebble bed PBR core, which is refueled continuously during reactor operations. Detailed studies of key technical issues using reference HTGR and PBR designs revealed that two cost components contributing to the levelized power costs are higher for the PBR: capital costs and operation and maintenance costs. A third cost component, associated with nonavailability penalties, tended to be higher for the PBR except for the process heat application, for which there is a large uncertainty in the HTGR nonavailability penalty at the 950 0 C outlet coolant temperature. A fourth cost component, fuel cycle costs, is lower for the PBR, but not sufficiently lower to offset the capital cost component. Thus the HTGR appears to be slightly superior to the PBR in economic performance. Because of the advanced development of the HTGR concept, large HTGRs could also be commercialized in the US with lower R and D costs and shorter lead times than could large PBRs. It is recommended that the US gas-cooled thermal reactor program continue giving primary support to the HTGR, while also maintaining its cooperative PBR program with FRG

  10. Fusion energy for alternate applications: the design of a high temperature falling bed as a long-lived blanket

    International Nuclear Information System (INIS)

    Harkness, S.D.; Stevens, H.C.; Hall, M.M.; Gohar, M.Y.A.; de Paz, J.F.

    1979-01-01

    The high temperature falling bed conceptual design work has consisted of a coordinated effort in neutronics, materials science, thermal hydraulics and mechanical design. The neutronics work has been based on a one-dimensional transport analysis and has been used to scope the implication of blanket dimensions, breeding materials, ceramic pebble material and coolant choice on both tritium breeding capabilities and energy deposition into the high temperature region of the blanket. The materials science effort has concentrated on defining the selection of a particular ceramic material. The thermal hydraulic analysis has been concerned with sizing the heat transfer system and defining the temperature gradients in the high temperature blanket. The mechanical design work has evaluated how such a system might be constructed from the point of view of maintainability and structural support

  11. Analytical calculation of the fuel temperature reactivity coefficient for pebble bed and prismatic high temperature reactors for plutonium and uranium-thorium fuels

    International Nuclear Information System (INIS)

    Talamo, Alberto

    2007-01-01

    We analytically evaluated the fuel coefficient of temperature both for pebble bed and prismatic high temperature reactors when they utilize as fuel plutonium and minor actinides from light water reactors spent fuel or a mixture of 50% uranium, enriched 20% in 235 U, and 50% thorium. In both cores the calculation involves the evaluation of the resonances integrals of the high absorbers fuel nuclides 240 Pu, 238 U and 232 Th and it requires the esteem of the Dancoff-Ginsburg factor for a pebble bed or prismatic core. The Dancoff-Ginsburg factor represents the only discriminating parameter in the results for the two different reactors types; in fact, both the pebble bed and the prismatic reactors share the same the pseudo-cross-section describing an infinite medium made of graphite filled by TRISO particles. We considered only the resolved resonances with a statistical spin factor equal to one and we took into account 267, 72, 212 resonances in the range 1.057-5692, 6.674-14485, 21.78-3472 eV for 240 Pu, 238 U and 232 Th, respectively, for investigating the influence on the fuel temperature reactivity coefficient of the variation of the TRISO kernel radius and TRISO particles packing fraction from 100, 200 to 300 μm and from 10% to 50%, respectively. Finally, in the pebble bed core, we varied the radius of the pebble for setting a fuel temperature reactivity coefficient similar to the one of a prismatic core

  12. Pebble Bed Reactors Design Optimization Methods and their Application to the Pebble Bed Fluoride Salt Cooled High Temperature Reactor (PB-FHR)

    Science.gov (United States)

    Cisneros, Anselmo Tomas, Jr.

    The Fluoride salt cooled High temperature Reactor (FHR) is a class of advanced nuclear reactors that combine the robust coated particle fuel form from high temperature gas cooled reactors, direct reactor auxillary cooling system (DRACS) passive decay removal of liquid metal fast reactors, and the transparent, high volumetric heat capacitance liquid fluoride salt working fluids---flibe (33%7Li2F-67%BeF)---from molten salt reactors. This combination of fuel and coolant enables FHRs to operate in a high-temperature low-pressure design space that has beneficial safety and economic implications. In 2012, UC Berkeley was charged with developing a pre-conceptual design of a commercial prototype FHR---the Pebble Bed- Fluoride Salt Cooled High Temperature Reactor (PB-FHR)---as part of the Nuclear Energy University Programs' (NEUP) integrated research project. The Mark 1 design of the PB-FHR (Mk1 PB-FHR) is 236 MWt flibe cooled pebble bed nuclear heat source that drives an open-air Brayton combine-cycle power conversion system. The PB-FHR's pebble bed consists of a 19.8% enriched uranium fuel core surrounded by an inert graphite pebble reflector that shields the outer solid graphite reflector, core barrel and reactor vessel. The fuel reaches an average burnup of 178000 MWt-d/MT. The Mk1 PB-FHR exhibits strong negative temperature reactivity feedback from the fuel, graphite moderator and the flibe coolant but a small positive temperature reactivity feedback of the inner reflector and from the outer graphite pebble reflector. A novel neutronics and depletion methodology---the multiple burnup state methodology was developed for an accurate and efficient search for the equilibrium composition of an arbitrary continuously refueled pebble bed reactor core. The Burnup Equilibrium Analysis Utility (BEAU) computer program was developed to implement this methodology. BEAU was successfully benchmarked against published results generated with existing equilibrium depletion codes VSOP

  13. Gas Turbine High Temperature Gas (Helium) Reactor Using Pebble Bed Fuel Derived from Spent Fuel

    International Nuclear Information System (INIS)

    Cole, Quentin

    2013-01-01

    Project goals: Build on the $1B investment spent during the NGNP Project for the only true Inherently Safe Small Modular Reactor Design – the only SMR design that can make this claim due to negative temperature coefficient of reactivity - no containment required – less construction cost. NPMC in Partnership with Pebble Bed Modular Group, a fully owned subsidiary of Eskom, RSA to Factory Build Complete Plant in Modular Sections at Factory Site in Oswego, NY for transport to site by rail or shipping for world wide export. NPMC will provide Project and Construction Management of all new builds from plant sites through construction, commissioning and startup using local labor. License and Construct ion of spent fuel processing facility in both NY and South Africa using Proven Technology. Ultimate goals of project: 1. Award of the 2013 US DOE Innovative SMR $452M cost share grant for US NRC License Certification 2.Build Full Scale Demonstration Plant at Koeburg, RSA with World Bank Funding managed by NPMC in collaboration with our legal firm, Haynes and Boone LLP 3. Take Plant Orders Immediately (10% Down Payment) 4. Form Strategic Alliance with Domestic and/or International Utility

  14. A kinetic study of gaseous potassium capture by coal minerals in a high temperature fixed-bed reactor

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

    2008-01-01

    The reactions between gaseous potassium chloride and coal minerals were investigated in a lab-scale high temperature fixed-bed reactor using single sorbent pellets. The applied coal minerals included kaolin, mullite, silica, alumina, bituminous coal ash, and lignite coal ash that were formed...... into long cylindrical pellets. Kaolin and bituminous coal ash that both have significant amounts of Si and Al show superior potassium capture characteristics. Experimental results show that capture of potassium by kaolin is independent of the gas oxygen content. Kaolin releases water and forms metakaolin...... when heated at temperatures above 450°C. The amounts of potassium captured by metakaolin pellet decreases with increasing reaction temperature in the range of 900-1300°C and increases again with further increasing the temperature up to 1500°C. There is no reaction of pre-made mullite with KCl...

  15. Theoretical and experimental research of natural convection in the core of the high temperature pebble bed reactor

    International Nuclear Information System (INIS)

    Schuerenkraemer, M.

    1984-04-01

    The physical model of the developed THERMIX-2D-code for computing thermohydraulic behaviour of the core of high temperature pebble bed reactors is verified by experiments with natural convection flow. Such fluid flow behaviour can be of very high importance for the real reactor in the case of natural heat removal decay. The experiments are performed in a special set up testing-stand with pressures up to 30 bars and temperatures up to 300 0 C by using air and helium as fluid. In comparison with the experimental data the numerical results show that a good and useful simulation is given by the program. Pure natural convection flow in packed pebble beds is calculated with a very high degree of reliability. The investigation of flow stability demonstrate that radial-symmetric relations are not given temporarily when national convection is overlayed by forced convection flow. In the discussion it is explained when and to what extent the program leds to useful results in such situations. The test of the effective heat conductivity lambdasub(eff) results in an improvement of the lambdasub(eff)-data used so far for temperatures below 1300 0 C. (orig.) [de

  16. The influence of thorium on the temperature reactivity coefficient in a 400 MWth pebble bed high temperature plutonium incinerating reactor

    International Nuclear Information System (INIS)

    Richards, Guy A.; Serfontein, Dawid E.

    2014-01-01

    This article investigates advanced fuel cycles containing thorium and reactor grade plutonium (Pu(PWR)) in a 400 MW th Pebble Bed Modular Reactor (PBMR) Demonstration Power Plant. Results presented were determined from coupled neutronics and thermo-hydraulic simulations of the VSOP 99/05 diffusion codes. In a previous study impressive burn-ups (601 MWd/kg heavy metal (HM)) and thus plutonium destruction rates (69.2 %) were obtained with pure plutonium fuel with mass loadings of 3 g Pu(PWR)/fuel sphere or less. However the safety performance was poor in that the limit on the maximum fuel temperature during equilibrium operation was exceeded and positive Uniform Temperature Reactivity Coefficients (UTCs) were obtained. In the present study fuel cycles containing mixtures of thorium and plutonium achieved negative maximum UTCs. Plutonium only fuel cycles also achieved negative maximum UTCs, provided that much higher mass loadings are used. It is proposed that the lower thermal neutron flux was responsible for this effect. The plutonium only fuel cycle with 12 g Pu(PWR)/fuel sphere also achieved the adopted safety limits for the PBMR DPP-400 in that the maximum fuel temperature and the maximum power density did not exceed 1130°C or 4.5 kW/sphere respectively. This design would thus be licensable and could potentially be economically feasible. However the burn-up was much lower at 181 MWd/kgHM and thus the plutonium destruction fraction was also much lower at 24.5%, which may be sub-optimal with respect to proliferation and waste disposal objectives and therefore further optimisation studies are proposed. (author)

  17. Analytical calculation of the fuel temperature reactivity coefficient for pebble bed and prismatic high temperature reactors for plutonium and uranium-thorium fuels

    Energy Technology Data Exchange (ETDEWEB)

    Talamo, Alberto [Department of Nuclear and Reactor Physics, Royal Institute of Technology - KTH, Roslagstullsbacken 21, S-10691 Stockholm (Sweden)]. E-mail: alby@anl.gov

    2007-01-15

    We analytically evaluated the fuel coefficient of temperature both for pebble bed and prismatic high temperature reactors when they utilize as fuel plutonium and minor actinides from light water reactors spent fuel or a mixture of 50% uranium, enriched 20% in {sup 235}U, and 50% thorium. In both cores the calculation involves the evaluation of the resonances integrals of the high absorbers fuel nuclides {sup 240}Pu, {sup 238}U and {sup 232}Th and it requires the esteem of the Dancoff-Ginsburg factor for a pebble bed or prismatic core. The Dancoff-Ginsburg factor represents the only discriminating parameter in the results for the two different reactors types; in fact, both the pebble bed and the prismatic reactors share the same the pseudo-cross-section describing an infinite medium made of graphite filled by TRISO particles. We considered only the resolved resonances with a statistical spin factor equal to one and we took into account 267, 72, 212 resonances in the range 1.057-5692, 6.674-14485, 21.78-3472 eV for {sup 240}Pu, {sup 238}U and {sup 232}Th, respectively, for investigating the influence on the fuel temperature reactivity coefficient of the variation of the TRISO kernel radius and TRISO particles packing fraction from 100, 200 to 300 {mu}m and from 10% to 50%, respectively. Finally, in the pebble bed core, we varied the radius of the pebble for setting a fuel temperature reactivity coefficient similar to the one of a prismatic core.

  18. Random detailed model for probabilistic neutronic calculation in pebble bed Very High Temperature Reactors

    International Nuclear Information System (INIS)

    Perez Curbelo, J.; Rosales, J.; Garcia, L.; Garcia, C.; Brayner, C.

    2013-01-01

    The pebble bed nuclear reactor is one of the main candidates for the next generation of nuclear power plants. In pebble bed type HTRs, the fuel is contained within graphite pebbles in the form of TRISO particles, which form a randomly packed bed inside a graphite-walled cylindrical cavity. Pebble bed reactors (PBR) offer the opportunity to meet the sustainability requirements, such as nuclear safety, economic competitiveness, proliferation resistance and a minimal production of radioactive waste. In order to simulate PBRs correctly, the double heterogeneity of the system must be considered. It consists on randomly located pebbles into the core and TRISO particles into the fuel pebbles. These features are often neglected due to the difficulty to model with MCPN code. The main reason is that there is a limited number of cells and surfaces to be defined. In this study, a computational tool which allows getting a new geometrical model of fuel pebbles for neutronic calculations with MCNPX code, was developed. The heterogeneity of system is considered, and also the randomly located TRISO particles inside the pebble. Four proposed fuel pebble models were compared regarding their effective multiplication factor and energy liberation profiles. Such models are: Homogeneous Pebble, Five Zone Homogeneous Pebble, Detailed Geometry, and Randomly Detailed Geometry. (Author)

  19. Pore Scale Thermal Hydraulics Investigations of Molten Salt Cooled Pebble Bed High Temperature Reactor with BCC and FCC Configurations

    Directory of Open Access Journals (Sweden)

    Shixiong Song

    2014-01-01

    CFD results and empirical correlations’ predictions of pressure drop and local Nusselt numbers. Local pebble surface temperature distributions in several default conditions are investigated. Thermal removal capacities of molten salt are confirmed in the case of nominal condition; the pebble surface temperature under the condition of local power distortion shows the tolerance of pebble in extreme neutron dose exposure. The numerical experiments of local pebble insufficient cooling indicate that in the molten salt cooled pebble bed reactor, the pebble surface temperature is not very sensitive to loss of partial coolant. The methods and results of this paper would be useful for optimum designs and safety analysis of molten salt cooled pebble bed reactors.

  20. US/FRG joint report on the pebble bed high temperature reactor resource conservation potential and associated fuel cycle costs

    International Nuclear Information System (INIS)

    Teuchert, E.; Ruetten, H.J.; Worley, B.A.; Vondy, D.R.

    1979-11-01

    Independent analyses at ORNL and KFA have led to the general conclusion that the flexibility in design and operation of a high-temperature gas-cooled pebble-bed reactor (PBR) can result in favorable ore utilization and fuel costs in comparison with other reactor types, in particular, with light-water reactors (LWRs). Fuel reprocessign and recycle show considerable promise for reducing ore consumption, and even the PBR throwaway cycle is competitive with fuel recycle in an LWR. The best performance results from the use of highly enriched fuel. Proliferation-resistant measures can be taken using medium-enriched fuel at a modest ore penalty, while use of low-enriched fuel would incur further ore penalty. Breeding is possible but net generation of fuel at a significant rate would be expensive, becoming more feasible as ore costs increase substantially. The 233 U inventory for a breeder could be produced by prebreeders using 235 U fuel

  1. Physics of the pebble-bed high temperature reactor in massive water ingress accidents

    International Nuclear Information System (INIS)

    Scherer, W.

    1989-10-01

    A point-kinetics model was developed to describe qualitatively hypothetical water ingress transients in the primary loop of High Temperature Reactors. Neutron kinetics, heat-flow balance and the chemical reaction of graphite corrosion together with their mutual influence are included. The qualitative behaviour of the transients is calculated and discussed for two fictitious examples, namely the long-term water ingress into a medium sized HTR (HTR-500) and the 'startup' of a small HTR after an intensive water flooding of the core. The model developed and the computer code KINKOR are thought to be tools for the general understanding of the water ingress phenomena and should be looked at as basis for more elaborated systems. (orig./HP) [de

  2. Simulation in CFD of a Pebble Bed: Advanced high temperature reactor core using OpenFOAM

    International Nuclear Information System (INIS)

    Dahl, Pamela M.; Su, Jian

    2017-01-01

    Numerical simulations of a Pebble Bed nuclear reactor core are presented using the multi-physics tool-kit OpenFOAM. The HTR-PM is modeled using the porous media approach, accounting both for viscous and inertial effects through the Darcy and Forchheimer model. Initially, cylindrical 2D and 3D simulations are compared, in order to evaluate their differences and decide if the 2D simulations carry enough of the sought information, considering the savings in computational costs. The porous medium is considered to be isotropic, with the whole length of the packed bed occupied homogeneously with the spherical fuel elements. Steady-state simulations for normal equilibrium operation are performed, using a semi sine function of the power density along the vertical axis as the source term for the energy balance equation.Total pressure drop is calculated and compared with that obtained from literature for a similar case. At a second stage, transient simulations are performed, where relevant parameters are calculated and compared to those of the literature. (author)

  3. Simulation in CFD of a Pebble Bed: Advanced high temperature reactor core using OpenFOAM

    Energy Technology Data Exchange (ETDEWEB)

    Dahl, Pamela M.; Su, Jian, E-mail: sujian@nuclear.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2017-07-01

    Numerical simulations of a Pebble Bed nuclear reactor core are presented using the multi-physics tool-kit OpenFOAM. The HTR-PM is modeled using the porous media approach, accounting both for viscous and inertial effects through the Darcy and Forchheimer model. Initially, cylindrical 2D and 3D simulations are compared, in order to evaluate their differences and decide if the 2D simulations carry enough of the sought information, considering the savings in computational costs. The porous medium is considered to be isotropic, with the whole length of the packed bed occupied homogeneously with the spherical fuel elements. Steady-state simulations for normal equilibrium operation are performed, using a semi sine function of the power density along the vertical axis as the source term for the energy balance equation.Total pressure drop is calculated and compared with that obtained from literature for a similar case. At a second stage, transient simulations are performed, where relevant parameters are calculated and compared to those of the literature. (author)

  4. Experimental investigation on feasibility of two-region-designed pebble-bed high-temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Yang Xingtuan; Hu Wenping; Jiang Shengyao

    2009-01-01

    Phenomenological experiments were performed on a 2-dimensional scaled model of the two-region designed pebble-bed high-temperature gas-cooled reactor core consisting of the distinct fuel pebble region and graphite pebble region. Issues with respect to the feasibility of the two-region design, including the establishment of the two-region arrangement, the mixing zone between the two regions, and the stagnant zone existence, were investigated. Three equilibrium conditions were proposed to evaluate the stable two-region arrangement formation. The general characteristics of the flow of the pebble bed were analyzed on basis of the observed phenomenon. It was found that a stable two-region arrangement was formed under the experimental conditions: the pebbles' motion was to some extent random but also confined by the neighbors of pebbles so that the mixing zone is constrained to a reasonable size. Guide plates utilized to improve mixing are proved to be effective without noticeable effect on the two-region arrangement features. Stagnant zones were observed under the experimental conditions and they were expected to be avoided by improving the design of the experimental setup. (author)

  5. Water-ingress analysis for the 200 MWe pebble-bed modular high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Zheng Yanhua; Shi Lei; Wang Yan

    2010-01-01

    Water ingress into the primary circuit is generally recognized as one of the severe accidents with potential hazard to the modular high temperature gas-cooled reactor adopting steam-turbine cycle, which will cause a positive reactivity introduction, as well as the chemical corrosion of graphite fuel elements and reflector structure material. Besides, increase of the primary pressure may result in the opening of the safety valves, consequently leading the release of radioactive isotopes and flammable water gas. The analysis of such a kind of important and particular accident is significant to verify the inherent safety characteristics of the modular HTR plants. Based on the preliminary design of the 200 MWe high temperature gas-cooled reactor pebble-bed modular (HTR-PM), the design basis accident of a double-ended guillotine break of one heating tube and the beyond design basis accident of a large break of the main steam collection plate have been analyzed by using TINTE code, which is a special transient analysis program for high temperature gas-cooled reactors. Some safety relevant concerns, such as the fuel temperature, the primary loop pressure, the graphite corrosion, the water gas releasing amount, as well as the natural convection influence on the condition of failing to close the blower flaps, have been studied in detail. The calculation results indicate that even under some severe hypothetical postulates, the HTR-PM is able to keep the inherent safeties of the modular high temperature gas-cooled reactor and has a relatively good natural plant response, which will not result in environmental radiation hazard.

  6. Long-term, high frequency in situ measurements of intertidal mussel bed temperatures using biomimetic sensors

    Science.gov (United States)

    Helmuth, Brian; Choi, Francis; Matzelle, Allison; Torossian, Jessica L.; Morello, Scott L.; Mislan, K.A.S.; Yamane, Lauren; Strickland, Denise; Szathmary, P. Lauren; Gilman, Sarah E.; Tockstein, Alyson; Hilbish, Thomas J.; Burrows, Michael T.; Power, Anne Marie; Gosling, Elizabeth; Mieszkowska, Nova; Harley, Christopher D.G.; Nishizaki, Michael; Carrington, Emily; Menge, Bruce; Petes, Laura; Foley, Melissa M.; Johnson, Angela; Poole, Megan; Noble, Mae M.; Richmond, Erin L.; Robart, Matt; Robinson, Jonathan; Sapp, Jerod; Sones, Jackie; Broitman, Bernardo R.; Denny, Mark W.; Mach, Katharine J.; Miller, Luke P.; O’Donnell, Michael; Ross, Philip; Hofmann, Gretchen E.; Zippay, Mackenzie; Blanchette, Carol; Macfarlan, J.A.; Carpizo-Ituarte, Eugenio; Ruttenberg, Benjamin; Peña Mejía, Carlos E.; McQuaid, Christopher D.; Lathlean, Justin; Monaco, Cristián J.; Nicastro, Katy R.; Zardi, Gerardo

    2016-01-01

    At a proximal level, the physiological impacts of global climate change on ectothermic organisms are manifest as changes in body temperatures. Especially for plants and animals exposed to direct solar radiation, body temperatures can be substantially different from air temperatures. We deployed biomimetic sensors that approximate the thermal characteristics of intertidal mussels at 71 sites worldwide, from 1998-present. Loggers recorded temperatures at 10–30 min intervals nearly continuously at multiple intertidal elevations. Comparisons against direct measurements of mussel tissue temperature indicated errors of ~2.0–2.5 °C, during daily fluctuations that often exceeded 15°–20 °C. Geographic patterns in thermal stress based on biomimetic logger measurements were generally far more complex than anticipated based only on ‘habitat-level’ measurements of air or sea surface temperature. This unique data set provides an opportunity to link physiological measurements with spatially- and temporally-explicit field observations of body temperature. PMID:27727238

  7. SHOVAV-JUEL. A one dimensional space-time kinetic code for pebble-bed high-temperature reactors with temperature and Xenon feedback

    International Nuclear Information System (INIS)

    Nabbi, R.; Meister, G.; Finken, R.; Haben, M.

    1982-09-01

    The present report describes the modelling basis and the structure of the neutron kinetics-code SHOVAV-Juel. Information for users is given regarding the application of the code and the generation of the input data. SHOVAV-Juel is a one-dimensional space-time-code based on a multigroup diffusion approach for four energy groups and six groups of delayed neutrons. It has been developed for the analysis of the transient behaviour of high temperature reactors with pebble-bed core. The reactor core is modelled by horizontal segments to which different materials compositions can be assigned. The temperature dependence of the reactivity is taken into account by using temperature dependent neutron cross sections. For the simulation of transients in an extended time range the time dependence of the reactivity absorption by Xenon-135 is taken into account. (orig./RW)

  8. High temperature fluidized bed zero valent iron process for flue gas nitrogen monoxide removal

    International Nuclear Information System (INIS)

    Cheng, C.Y.; Chen, S.S.; Tang, C.H.; Chang, Y.M.; Cheng, H.H.; Liu, H.L.

    2008-01-01

    Nitrogen oxides (NO x ) are generated from a variety of sources, and are critical components of photochemical smog. Zero valent iron (ZVI) has been used to remove NO x in a number of studies. The ZVI process requires no extra chemicals or catalysts. In this study, a fluidized ZVI process for removing NO x from flue gases was proposed. The study examined the effects of temperature, ZVI dosage and influent NO concentrations, and observed the kinetic effects between the fluidized ZVI and NO x . A life cycle analysis of the process was also provided. The parametric analysis was conducted in a series of column studies using a continuous emissions monitoring system. Minimum fluidization velocity equations were provided, and the drag coefficient was determined. Capacities of ZVI for NO removal at different temperatures were calculated. Results of the study suggested that temperature, influent concentrations, and flow rates all influenced kinetic coefficients. Different temperatures resulted in different rates of NO removal. It was concluded that between 673 K and 773 K, almost complete NO removals were achieved. 14 refs., 2 tabs., 9 figs

  9. A systems CFD model of a packed bed high temperature gas-cooled nuclear reactor

    International Nuclear Information System (INIS)

    Du Toit, C.G.; Rousseau, P.G.; Greyvenstein, G.P.; Landman, W.A.

    2006-01-01

    The theoretical basis and conceptual formulation of a comprehensive reactor model to simulate the thermal-fluid phenomena of the PBMR reactor core and core structures is given. Through a rigorous analysis the fundamental equations are recast in a form that is suitable for incorporation in a systems CFD code. The formulation of the equations results in a collection of one-dimensional elements (models) that can be used to construct a comprehensive multi-dimensional network model of the reactor. The elements account for the pressure drop through the reactor; the convective heat transport by the gas; the convection heat transfer between the gas and the solids; the radiative, contact and convection heat transfer between the pebbles and the heat conduction in the pebbles. Results from the numerical model are compared with that of experiments conducted on the SANA facility covering a range of temperatures as well as two different fluids and different heating configurations. The good comparison obtained between the simulated and measured results show that the systems CFD approach sufficiently accounts for all of the important phenomena encountered in the quasi-steady natural convection driven flows that will prevail after critical events in a reactor. The fact that the computer simulation time for all of the simulations was less than three seconds on a standard notebook computer also indicates that the new model indeed achieves a fine balance between accuracy and simplicity. The new model can therefore be used with confidence and still allow quick integrated plant simulations. (authors)

  10. Localization of the Hot Spot in the Gap of Pebble Bed of Very High Temperature Gas Cooled Reactor(VHTGR)

    International Nuclear Information System (INIS)

    Lee, Sa Ya; Hong, Sung Je; Lee, Jae Young

    2010-01-01

    Pebble Bed Reactor(PBR) has been investigated intensively due to its benefits in management, but its complicated flow geometry requests reliable analytical methods. Hassan and Lee et al. have been made three dimensional computational methods. Hassan also measured local velocity fields with Particle Tracking Velocimetry(PTV), in small sized packed bed using liquid coolant, and Lee et al. measured flow field in the 2-dimensional wind tunnel with a hot wire system. In the present study, we develop the scaled up wind tunnel of pebble bed to use air as coolant in the same Reynolds number condition, as 21614, of the PBMR-250MWth. In order to measure the local surface temperature, the heating system and temperature measurement system were installed and heat transfer analogy was performed. The local surface temperature data shows that the predicted hot spots by Lee et al. at the top and bottom of the pebble by the velocity field measurement are reasonable, but the heat conduction is prior than contact effect at contact points

  11. Sustainability of thorium-uranium in pebble-bed fluoride salt-cooled High Temperature Reactor - 15171

    International Nuclear Information System (INIS)

    Zhu, G.; Zou, Y.; Xu, Hongjie

    2015-01-01

    Sustainability of thorium fuel in a pebble-bed fluoride salt-cooled high temperature reactor (PB-FHR) is investigated to find the feasible region of high discharge burnup and negative FLiBe (2LiF-BeF 2 ) salt temperature reactivity coefficient (TRC). Dispersion fuel or pellet fuel with SiC cladding and SiC matrix is used to replace the tri-structural-isotropic (TRISO) coated particle system for increasing heavy metal loading and decreasing excessive moderation. In order to analyze the neutronic characteristics, an equilibrium calculation method of thorium fuel self-sustainability is developed. We have compared 2 refueling schemes (mixing flow pattern and directional flow pattern) and 2 kinds of reflector materials (SiC and graphite). This method has found that the feasible regions of breeding and negative FLiBe TRC is between 20 vol% and 62 vol% heavy metal loading in the fuel. A discharge burnup could be achieved up to about 200 MWd/kgHM. The case with directional flow pattern and SiC reflector showed superior burnup characteristics but the worst radial power peak factor, while the case with mixing flow pattern and SiC reflector, which was the best tradeoff between discharge burnup and radial power peak factor, could provide burnup of 140 MWd/kgHM and about 1.4 radial power peak factor with 50 vol% dispersion fuel. In addition, FLiBe salt displays good neutron properties as a coolant of quasi-fast reactors due to the strong 9 Be(n,2n) reaction and low neutron absorption of 6 Li (even at 1000 ppm) in fast spectrum. Preliminary thermal hydraulic calculation shows good safety margins. The greatest challenge of this reactor may be the very long irradiation time of the pebble fuel. (authors)

  12. Numerical investigation of the 3-dimensional steady-state temperature- and flow distribution in the core of a pebble bed high temperature reactor

    International Nuclear Information System (INIS)

    Verfondern, K.

    1983-01-01

    This work presents a computer model determining the steady-state temperature- and flow field in 3 dimensions in the core of a pebble bed high temperature reactor. The numerical sprinkler method, basind on the Thermix-model, allows to describe the thermo-hydraulics of a non-rotational-symmetric core-geometry. The AVR-reactor in Juelich, in operation since 1967, represents a suitable investigation-object for the computer model of Thermix-3D. It is in a 3D-mesh-structure to reproduce very precisely the so called ''graphite noses'', in which the shut-down rods are conducted as well as the filling cones in the inner and outer area. The results of the final calculation of the normal operation condition for the AVR-reactor unambiguously show, that within the core reproduced in 3 dimensions there are evident deviations in the flow profile and in the temperatures of the cooling gas in contrast to a 2D-handling. (orig.) [de

  13. Methodology of the On-Iine FoIIow Simulation of Pebble-bed High-temperature Reactors

    International Nuclear Information System (INIS)

    Xia Bing; Li Fu; Wei Chunlin; Zheng Yanhua; Chen Fubing; Zhang Jian; Guo Jiong

    2014-01-01

    The on-line fuel management is an essential feature of the pebble-bed high-temperature reactors (PB-HTRs), which is strongly coupled with the normal operation of the reactor. For the purpose of on-line analysis of the continuous shuffling scheme of numerous fuel pebbles, the follow simulation upon the real operation is necessary for the PB-HTRs. In this work, the on-line follow simulation methodology of the PB-HTRs’ operation is described, featured by the parallel treatments of both neutronics analysis and fuel cycling simulation. During the simulation, the operation history of the reactor is divided into a series of burn-up cycles according to the behavior of operation data, in which the steady-state neutron transport equations are solved and the diffusion theory is utilized to determine the physical features of the reactor core. The burn-up equations of heavy metals, fission products and neutron poisons including B-10, decoupled from the pebble flow term, are solved to analyze the burn-up process within a single burn-up cycle. The effect of pebble flow is simulated separately through a discrete fuel shuffling pattern confined by curved pebble flow channels, and the effect of multiple pass of the fuel is represented by logical batches within each spatial region of the core. The on-line thermal-hydraulics feedback is implemented for each bur-up cycle by using the real thermal-hydraulics data of the core operation. The treatment of control rods and absorber balls is carried out by utilizing a coupled neutron transport-diffusion calculation along with discontinuity factors. The physical models mentioned above are established mainly by using a revised version of the V.S.O.P program system. The real operation data of HTR-10 is utilized to verify the methodology presented in this work, which gives good agreement between simulation results and operation data. (author)

  14. Modeling and Application of Pneumatic Conveying for Spherical Fuel Element in Pebble-Bed Modular High-Temperature Gas-Cooled Reactor

    International Nuclear Information System (INIS)

    Zhou Shuyong; Wang Junsan; Wang Yuding; Cai Ruizhong; Zhang Xuan; Cao Jianting

    2014-01-01

    The fuel handling system is an important system for on-load refueling in pebble-bed modular high-temperature gas-cooled reactor. A dynamic model of pneumatic conveying for spherical fuel element in fuel handling system was established to describe the pneumatically conveying process. The motion characteristics of fuel elements in pipeline and the effect of fuel elements on gas velocity were studied using the model. The results show that the theoretical analyses are consistent with the experimental. The research has been used in developing full scope simulator for pebble-bed modular high-temperature gas-cooled reactor, also provides references for the design and optimization of the fuel handling system. (author)

  15. Development and application of a high-temperature sampling probe for burning chamber conditions of fluidized-bed combustion; Korkean laempoetilan naeytteenottosondin kehittaeminen ja soveltaminen leijukerrospolton tulipesaeolosuhteisiin

    Energy Technology Data Exchange (ETDEWEB)

    Larjava, K.; Paerkkae, M.; Jormanainen, P.; Roine, J.; Paakkinen, K. [VTT Chemistry, Espoo (Finland); Linna, V. [VTT Energy, Jyvaeskylae (Finland)

    1996-12-01

    A sampling probe for the burning chamber conditions of fluidized-bed combustion will be developed in this project. The probe will be suitable for sampling vaporous heavy and alkali metals and other condensing compounds (e.g. chlorides) as well combustion gases and alternatively also flue gas particles at high temperatures. The knowledge gained with the probe will help understanding, developing and modeling combustion processes and will thus aid the manufacturers of the boilers. (author)

  16. FY 1974 Report on results of Sunshine Project. Feasibility study on digging high-temperature beds; 1974 nendo koon chiso kussaku ni kansuru feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1975-03-31

    The desired target geothermal conditions for which the digging equipment is to be developed are 3,000 to 5,000 m as depth, 400 degrees C as temperature and 500 kg/cm{sup 2} as pressure. As the first phase, the study is conducted on feasibility of development of techniques for digging high-temperature beds under a temperature condition of 250 degrees C, where the rotary table type digger is mainly studied. It is most widely used for digging oil wells as well as geothermal wells. The current rotary table B type digger is studied as the equipment serviceable at 250 degrees C as the target temperature level for the moment for digging high-temperature beds. The studied items include the problems involved in the digger body, pipes, bits and other members, and also measures to expand its possibility. Also studied/surveyed are applicability of the new digging techniques now under development to geothermal wells, and techniques for fracturing high-temperature rocks. This report summarizes to help select the methods desired to be developed in the future, and plan development of the digging systems. (NEDO)

  17. Temperature distribution in spouted bed and heat transfer

    International Nuclear Information System (INIS)

    Takeda, Hiroshi; Yamamoto, Yutaka

    1976-01-01

    Temperature distribution in spouted bed was measured by using brass and graphite spouted beds so as to investigate heat transfer characteristic of spouted bed applied to an apparatus of PyC coating. These spouted beds are batch type and are spouted by air or nitrogen gas of room temperature, and the outer wall of beds are heated by nichrome or graphite heater. Particles used for experiments are alumina spherical particles and the diameter is 0.80 -- 1.12 mm. Temperature condition is in the range of 400 -- 1,400 0 C. In the neighborhood of 400 0 C, the spouting condition is stable, while the spouting condition becomes unstable in the case of above 1,000 0 C. This is caused by abrupt temperature increase of spouting gas. It was found that heat transfer coefficient h sub(w) of our low temperature experiments was closer to the calculated from Malek et al.'s equation, h sub(p) of our experiments was several times greater than the calculated from Uemaki et al.'s equation. On the other hand, h sub(p) of high temperature experiments was compared with an experimental relation for convective heat transfer of fluidized bed, it was found that Nu sub(p) of our experiments was nearly equal to or greater than the calculated from the relation, this would be caused by radiant heat transfer. (auth.)

  18. Development and application of a high-temperature sampling probe for burning chamber conditions in fluidized-bed combustion; Korkean laempoetilan naeytteenottosondin kehittaeminen ja soveltaminen leijukerrospolton tulipesaeolosuhteisiin

    Energy Technology Data Exchange (ETDEWEB)

    Larjava, K.; Paerkkae, M. [VTT Chemical Technology, Espoo (Finland); Linna, V. [VTT Energy, Jyvaeskylae (Finland). Environmental Technology

    1997-10-01

    Determination of heavy and alkali metals and other condensing compounds (e.g. chlorides) in combustion chamber conditions is limited by the poor suitability of traditional methods for sampling at high temperatures. IFRF has developed a high-temperature sampling probe for sampling HCN and NH{sub 3}, which has been tested for sampling of NH{sub 3} by Chalmers University of Technology in Sweden. VTT Chemical Technology and Chalmers University of Technology have in their preliminary experiments determined contents of vaporous heavy metals in the combustion chamber of a 12 MW circulating fluidized-bed boiler using this probe. According to the results, the modified probe is suitable for heavy metal determination in combustion chamber. Based on this series of experiments, modification of the probe has been started on the own financing of VTT Chemical Technology and a field measurement was performed in November 1994 to test the present version of the probe. Based on the results of that measurement, the probe has been modified further on as a part of this LIEKKI 2 project. Similar kind of a principle has been applied in the probe which has been developed by VTT Energy during 1994. The probe is built for determination of gas composition of fluidized bed in full-scale boilers. The purpose of this project is to develop and test a sampling probe for fluidized bed combustion. The main advantage of the probe is that condensation losses in sampling due to high temperature gradients can be avoided. Thus, the probe is very suitable for sampling vaporous heavy and alkali metals and other condensing species as well as burning gases and alternatively also solids at high temperatures

  19. Predicted peak temperature-rises around a high-level radioactive waste canister emplaced in the deep ocean bed

    International Nuclear Information System (INIS)

    Kipp, K.L.

    1978-06-01

    A simple mathematical model of heat conduction was used to evaluate the peak temperature-rise along the wall of a canister of high-level radioactive waste buried in deep ocean sediment. Three different amounts of vitrified waste, corresponding to standard Harvest, large Harvest, and AVM canisters, and three different waste loadings were studied. Peak temperature-rise was computed for the nine cases as a function of canister geometry and storage time between reprocessing and burial. Lower waste loadings or longer storage times than initially envisaged are necessary to prevent the peak temperature-rise from exceeding 200 0 C. The use of longer, thinner cylinders only modestly reduces the storage time for a given peak temperature. Effects of stacking of waste canisters and of close-packing were also studied. (author)

  20. On natural circulation in High Temperature Gas-Cooled Reactors and pebble bed reactors for different flow regimes and various coolant gases

    International Nuclear Information System (INIS)

    Melesed'Hospital, G.

    1983-01-01

    The use of CO 2 or N 2 (heavy gas) instead of helium during natural circulation leads to improved performance in both High Temperature Gas-Cooled Reactors (HTGR) and in Pebble Bed Reactors (PBR). For instance, the coolant temperature rise corresponding to a coolant pressure level and a rate of afterheat removal could be only 18% with CO 2 as compared to He, for laminar flow in HTGR; this value would be 40% in PBR. There is less difference between HTGR and PBR for turbulent flows; CO 2 is found to be always better than N 2 . These types of results derived from relationships between coolant properties, coolant flow, temperature rise, pressure, afterheat levels and core geometry, are obtained for HTGR and PBR for various flow regimes, both within the core and in the primary loop

  1. Use of plutonium and minor actinides as fuel in high temperature pebble bed reactors for waste minimization

    International Nuclear Information System (INIS)

    Meier, Astrid; Bernnat, Wolfgang; Lohnert, Guenther

    2009-01-01

    Energy production by nuclear fission gives rise to longlived radionuclides, such as plutonium and americium. The ''PuMA'' (Plutonium and Minor Actinides Waste Management) research project within the 6th Framework Program of the European Union serves to minimize waste arisings and transmute plutonium and minor actinides from spent LWR fuel elements by means of modular high-temperature reactors (HTR). Coating the fuel, which consists of kernels approx. 250 μm in radius and surrounded by graphite as the moderator material, allows very high operating and accident temperatures and very high burnups. One point examined is whether the inherent safety characteristics known for uranium oxide also exist for (PuO 2 + MAO 2 ) fuel. On the basis of a reference reactor similar to the South African PBMR-400, various loading strategies at maximum burnup are considered with a view to the inherent safety of the HTR. (orig.)

  2. The pebble-bed high-temperature reactor as a source of nuclear process heat. Vol. 3

    International Nuclear Information System (INIS)

    Kugeler, K.; Schulten, R.; Kugeler, M.; Niessen, H.F.; Roeth-Kamat, M.; Hohn, H.; Woike, O.; Germer, J.H.

    1974-08-01

    The characteristic questions concerning a process heat reactor with high helium outlet temperatures are dealt with in this volume like e.g. fuel element design, corrosion, and fission product release. Furthermore, some possibilities of the technical realization of the hot-gas ducting and intermediate heat exchangers are described. Important parameters for the design of the reactor such as core power density, helium inlet and outlet temperatures, helium pressure and fuel cycle burn-up and conversion and the effect of these on the primary circuit are investigated. The important question regarding which reactor vessel is to be chosen for nuclear process heat plants is discussed with the aid of the integrated and non-integrated concepts using prestressed concrete, cast iron and cast steel. Thereafter, considerations on the safety of the nuclear plant are given. Finally, mention is made of the availability of the nuclear plant and of the status of development of the HTR technology. (orig.) [de

  3. User's manual for ASTERIX-2: A two-dimensional modular code system for the steady state and xenon transient analysis of a pebble bed high temperature reactor

    International Nuclear Information System (INIS)

    Wu, T.; Cowan, C.L.; Lauer, A.; Schwiegk, H.J.

    1982-03-01

    The ASTERIX modular code package was developed at KFA Laboratory-Juelich for the steady state and xenon transient analysis of a pebble bed high temperature reactor. The code package was implemented on the Stanford Linear Accelerator Center Computer in August, 1980, and a user's manual for the current version of the code, identified as ASTERIX-2, was prepared as a cooperative effort by KFA Laboratory and GE-ARSD. The material in the manual includes the requirements for accessing the program, a description of the major subroutines, a listing of the input options, and a listing of the input data for a sample problem. The material is provided in sufficient detail for the user to carry out a wide range of analysis from steady state operations to the xenon induced power transients in which the local xenon, temperature, buckling and control feedback effects have been incorporated in the problem solution. (orig.)

  4. The pebble-bed high-temperature reactor as a source of nuclear process heat. Vol. 10

    International Nuclear Information System (INIS)

    Schulten, R.; Kugeler, K.; Kugeler, M.; Niessen, H.F.; Roeth-Kamat, M.; Woike, O.

    1974-08-01

    The necessary development steps, which have to be taken for the construction of a prototype plant for nuclear process heat, are enumerated. In particular, the work which is involved for the development of the nuclear steam-reforming technique, for the further development of the ball-shaped fuel elements at high gas outlet temperatures and for the reactor components, is described in detail. A brief survey of the needs of development of the IHX (intermediate heat exchanger) is given. An attempt is made to give overall time and cost estimates. (orig.) [de

  5. Calcium oxide/carbon dioxide reactivity in a packed bed reactor of a chemical heat pump for high-temperature gas reactors

    International Nuclear Information System (INIS)

    Kato, Yukitaka; Yamada, Mitsuteru; Kanie, Toshihiro; Yoshizawa, Yoshio

    2001-01-01

    The thermal performance of a chemical heat pump that uses a calcium oxide/carbon dioxide reaction system was discussed as a heat storage system for utilizing heat output from high temperature gas reactors (HTGR). Calcium oxide/carbon dioxide reactivity for the heat pump was measured using a packed bed reactor containing 1.0 kg of reactant. The reactor was capable of storing heat at 900 deg. C by decarbonation of calcium carbonate and generating up to 997 deg. C by carbonation of calcium oxide. The amount of stored heat in the reactor was 800-900 kJ kg -1 . The output temperature of the reactor could be controlled by regulating the carbonation pressure. The thermal storage performance of the reactor was superior to that of conventional sensible heat storage systems. A heat pump using this CaO/CO 2 reactor is expected to contribute to thermal load leveling and to realize highly efficient utilization of HTGR output due to the high heat storage density and high-quality temperature output of the heat pump

  6. Mathematical modeling of a fluidized bed gasifier for steam gasification of coal using high-temperature nuclear reactor heat

    International Nuclear Information System (INIS)

    Kubiak, H.; vanHeek, K.-H.; Juntgen, H.

    1986-01-01

    Coal gasification is a well-known technique and has already been developed and used since a long time. In the last few years, forced by the energy situation, new efforts have been made to improve known processes and to start new developments. Conventional gasification processes use coal not only as feedstock to be gasified but also for supply of energy for reaction heat, steam production, and other purposes. With a nuclear high temperature reactor (HTR) as a source for process heat, it is possible to transform the whole of the feed coal into gas. This concept offers advantages over existing gasification processes: saving of coal, as more gas can be produced from coal; less emission of pollutants, as the HTR is used for the production of steam and electricity instead of a coal-fired boiler; and lower production costs for the gas

  7. Neutron physical investigations on the shutdown effect of small boronated absorbing spheres for pebble-bed high-temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Sgouridis, S.; Schurrer, F.; Muller, H.; Ninaus, W.; Oswald, K.; Neef, R.D.; Schaal, H.

    1987-01-01

    An emergency shutdown system for high-temperature gas-cooled pebble-bed reactors is proposed in addition to the common absorber rod shutdown system. This system is based on the strongly absorbing effect of small boronated graphite spheres (called KLAK), which trickle in case of emergency by gravity from the top reflector into the reactor core. The inner reflector of the Siemens-Argonaut reactor was substituted by an assembly of spherical Arbeitsgemeinschaft Versuchsreaktor fuel elements, and the shutdown effect was examined by installing well-defined KLAK nests inside this assembly. The purpose was to develop and prove a calculational procedure for determining criticality values for assemblies of large fuel spheres and small absorbing spheres

  8. Control of the Bed Temperature of a Circulating Fluidized Bed Boiler by using Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    AYGUN, H.

    2012-05-01

    Full Text Available Circulating fluidized bed boilers are increasingly used in the power generation due to their higher combustion efficiency and lower pollutant emissions. Such boilers require an effective control of the bed temperature, because it influences the boiler combustion efficiency and the rate of harmful emissions. A Particle-Swarm-Optimization-Proportional-Integrative-Derivative (PSO-PID controller for the bed temperature of a circulating fluidized bed boiler is presented. In order to prove the capability of the proposed controller, its performances are compared at different boiler loads with those of a Fuzzy Logic (FL controller. The simulation results demonstrate some advantages of the proposed controller.

  9. Studies on high-performance ceramic heat exchanger for ultra high temperature. 2nd Report. Heat transfer of finned tube bundle immersed in fluidized bed; Chokoon`yo koseino ceramic netsu kokanki ni kansuru kenkyu. 2. Ryudo sonai no rin kangun no netsudentatsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Himeji, Y; Kumada, M [Gifu University, Gifu (Japan). Faculty of Engineering

    1998-03-25

    Studies were carried out to develop a high-performance ceramic heat exchanger for ultra high temperatures using a fluidized bed. In the former study, Heat transfer coefficient had been improved by applying fluidized bed to the heat exchanger for high temperature with smooth ceramic tubes. In this study, finned ceramic tubes were applied instead of smooth tubes for more improvement of heat transfer and experiments were performed on condition that the maximum bed temperature was 1100degC. Fluidization remained stable and the bed temperature uniform in the bed similarly as the case of smooth tube. A heat transfer coefficient of finned tube was evaluated and it was improved about 3 times as large as that of smooth tube. The performance of the heat exchanger was also evaluated using temperature efficiency and exergy efficiency. 4 refs., 11 figs., 1 tab.

  10. Feasibility study - Lowered bed temperature in Fluidised Bed boilers for waste; Foerstudie - Saenkt baeddtemperatur i FB-pannor foer avfallsfoerbraenning

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Fredrik

    2009-01-15

    Waste incineration generally serves two purposes; 1) dispose of waste and 2) generation of heat and power. In the process of power production from waste fuels, the steam temperatures in super heaters are generally limited by the severe fouling and corrosion that occurs at elevated material temperatures, caused by high concentrations of alkali metals and chloride in the flue gas and fly ash. The overall aim of a continuation of present project is to determine if a reduced temperature of the bed zone in a fluidized bed waste incinerator reduces the amount of alkali chlorides in the flue gas. If so, a reduced bed temperature might enable increased steam temperature in super heaters, or, at unchanged steam temperature, improve the lifespan of the super heaters. The results from the project are of interest for plant owners wishing to improve performance of existing plants. The results may also be used to modify the design of future plants by boiler manufacturers. The aim of present pre-study was to determine how far the bed temperature can be reduced in a waste fired fluidized bed boiler in Boraas while maintaining a stable operation with sufficient combustion temperature in the freeboard to fulfil the directives of waste incineration. A continuation of the project will be based on the results from present study. The work is based on experiments at the test boiler. During the present study, no other measurements were performed apart from some sampling of bed material and ashes at different modes of operation. The experiments show that it is possible to alter the air and recycled flue gas in such a manner that the bed temperature is reduced from about 870 deg C to 700 deg C at 100% load and normal fuel mixture, while fulfilling the directive of 850 deg C at 2 seconds. Within normal variations of the fuel properties, however, the bed temperature increases to somewhat above 700 deg C if the fuel turns dry, while it falls below 650 deg C when the fuel turns wet. With

  11. FY 1975 Report on results of Sunshine Project. Development of techniques of digging high-temperature beds (Feasibility study on digging high-temperature beds); 1975 nendo koon chiso kussaku gijutsu no kaihatsu seika hokokusho. Koon chiso kussaku ni kansuru feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1976-03-31

    The environmental conditions for which the digging techniques are to be developed have been set at 3,000 to 5,000 m as depth, 400 degrees C as temperature and 500 kg/cm{sup 2} as pressure. The environmental temperature was set at 250 degrees C as the first phase in the previous year. In this year, the temperature level is increased to 400 degrees C for the feasibility study on technological development. For development of the high-temperature bed digging apparatuses, masts, sub-structures, drawworks, slurry pumps, and pipe addition handling are studied as the problems involved in the rotary table method. Also studied are the related themes, e.g., drill pipes, drill collars, casing pipes, slurry, cementing and instruments to be installed in geothermal wells. For development of the bits, various problems to be solved are studied, including slurry circulation systems, bit diameter and speed of rotation, and bit configurations as those involved in the digging systems; heat-resistant materials, bit tooth forms, hardening of the edges, bearing configurations and cooling mechanisms as those involved in the bit structures; and optimum service conditions and selective use standards for roller cutter and solid bits. Other items studied include structures of the apparatuses for geothermal well mouth, and wear of digging tools for the air drilling method. (NEDO)

  12. High power density reactors based on direct cooled particle beds

    Science.gov (United States)

    Powell, J. R.; Horn, F. L.

    Reactors based on direct cooled High Temperature Gas Cooled Reactor (HTGR) type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out along the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBRs) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed.

  13. Finite difference program for calculating hydride bed wall temperature profiles

    International Nuclear Information System (INIS)

    Klein, J.E.

    1992-01-01

    A QuickBASIC finite difference program was written for calculating one dimensional temperature profiles in up to two media with flat, cylindrical, or spherical geometries. The development of the program was motivated by the need to calculate maximum temperature differences across the walls of the Tritium metal hydrides beds for thermal fatigue analysis. The purpose of this report is to document the equations and the computer program used to calculate transient wall temperatures in stainless steel hydride vessels. The development of the computer code was motivated by the need to calculate maximum temperature differences across the walls of the hydrides beds in the Tritium Facility for thermal fatigue analysis

  14. Analysis of the delayed afterheat removal for a pebble-bed high temperature reactor concept as a contribution to the possibility for limitation of hypothetical accidents

    International Nuclear Information System (INIS)

    Rehm, W.

    1980-02-01

    The report presents the analysis of thermodynamic transients for a pebble-bed HTR concept which occur during the delayed after-heat removal of an overheated HTR-core. The consequences of the temperature behaviour are considered for the components of the circuit and the heat exchanger. The analysis is based on a core heatup following a depressurization of the primary circuit and a hypothetical loss of all the redundant cooling systems. By means of calculations it is demonstrated that a regular core structure and a coolable circuit geometry remain. In addition, it appears that the efficiency of the first fission product barrier is not impaired. The slow temperature transients of 2 0 C/min allow the possibility to restart failed afterheat loops to limit the temperature excursion. Provided that certain design and control features are incorporated, the afterheat removal systems can be restarted successfully even after long delay periods. During corresponding emergency procedures the heat exchangers are not demaged. The problems arising from failure limits for specific concepts must be solved. The consequences of total failure of afterheat removal systems are discussed. These consequences can be limited by taking into account the characteristic features of the HTR-system together with additional counter-measures. (orig.) [de

  15. High power density reactors based on direct cooled particle beds

    International Nuclear Information System (INIS)

    Powell, J.R.; Horn, F.L.

    1985-01-01

    Reactors based on direct cooled HTGR type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out long the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBR's) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed. 12 figs

  16. Effect of heat source shape on the thermal field in the pebble bed core of High Temperature Gas-cooled Reactor (HTGR)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Leisheng; Lee, Jaeyoung [Handong Global University, Pohang (Korea, Republic of)

    2015-10-15

    In this study, in order to minimize the error brought by non-uniform heat flux, the spherical heaters are employed as heat source; subsequently, thermal field and heat transfer characteristics of the pebbles are investigated. The thermal field of the pebble surface in PBR is measured with heat source in different shapes. The HTGR design concept exhibits excellent safety features due to the low power density and the large amount of graphite present in the core which gives a large thermal inertia in an accident such as loss of coolant. However, the possible appearance of hot spots in the pebble bed cores of HTGR may affect the integrity of the pebbles, which has drawn the attention of many scientists to investigate the thermal field and to predict the maximum temperature locations in the pebbles using CFD method, Lee et.al has also done some experimental work on measuring the surface temperature of the pebbles as well as visualizing flow patterns of the coolant gas, and it was found that the temperature near the contacting points between pebbles was not higher than the flow stagnation points due to the higher thermal conductivity of the pebble. Certain error of temperature measurement might occur because of not very uniform heat flux in the pebbles since heater in cylindrical shape was utilized as heat source in previous experiment. More uniform heat flux and more complicated thermal profile are found in the result obtained using spherical heaters. The result shows that the temperature in contact point is higher than that in the top point, which is different from the previous results. The complex thermal phenomena observed in the lower-half side-sphere can be explained by the flow pattern near the surface.

  17. FY 1975 Report on results of Sunshine Project. Development of techniques of digging high-temperature beds (Conceptual designs of automatic digging systems); 1975 nendo koon chiso kussaku gijutsu no kaihatsu seika hokokusho. Jido kussaku system no gainen sekkei

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1976-03-31

    This project is aimed at development of automatic rotary table type digging apparatus capable of digging high-temperature beds of 3,000 to 5,000 m in depth, 400 degrees C and 500 kg/cm{sup 2}. The automatic excavation apparatus is designed based on the concept that the driller is separated from the running drawworks side for other works. However, it is operated manually in a traditional manner, when the bed for which it is to be used is under complex conditions, or when the bed properties require frequent changes in digging conditions with respect to bit load and speed of rotation. The apparatus works, when the bed is considered to be under essentially constant conditions at a fairly high depth, in such a way that a combination of bit load and speed of rotation is set by the driller, and the work line wound on the drawworks drum is let out to keep the bit load constant. It is equipped with, e.g., a controller, converter and brake operating device, detecting suspension load by the controller, when it increases, increasing speed of air motor after comparing the load with the reference level, and relaxing the brake, to keep the suspension load at the set level. When the suspension load decreases, on the other hand, the air motor is decelerated to tighten the brake. (NEDO)

  18. Report on research and development achievements in fiscal 1980 in Sunshine Project. Development of a high-temperature bed drilling technology (Feasibility study on high-temperature bed drilling); 1980 nendo koon chiso kusaku gijutsu no kaihatsu seika hokokusho. Koon chiso kussaku ni kansuru feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1981-03-01

    Discussions were given on feasibility of a technology to drill efficiently a high-temperature bed (350 degrees C and 400 kg/cm{sup 2}) to 3 to 5 km. This paper summarizes the bit items for development (bearings, cutters, blade tips, sealing materials, a tip retaining method and structures). The roller cutter bit had the retaining power of the mother cutter material strengthened by using improved carbonized steel and heat treatment. A bit bearing using heat resistant material showed a life of 40 hours or longer at 350 degrees C. The solid bit using a two-layered ultra hard blade tip achieved a drilling rate of 0.84 m/h without any breakage. Studies were also advanced on the air friction drilling method. This paper also dwelled on heat and corrosion resistant blade tips, materials, enhancement of heat resistance in powder sintered cutters, and studies on the bit sealing. In addition to discussions on the percussion drilling as a new drilling method, discussions were given on slanted drilling, air drilling and multi-leg drilling. The paper summarizes these discussions together with development problems to be solved in the future. Research and development works were carried out also on an explosion preventing device, a roll packer, and a rotating head prevent device. (NEDO)

  19. Ash behavior and de-fluidization in low temperature circulating fluidized bed biomass gasifier

    DEFF Research Database (Denmark)

    Narayan, Vikas

    ensures that high-alkali biomass fuels can be used without risks of bed de-fluidization. This thesis aims to understand the behavior of alkali metals and ash in the LTCFB system. The thesis work involved measurements made on bed material and product gas dust samples on a 100kW LTCFB gasifier placed......Biomass is increasingly used as a fuel for power generation. Herbaceous fuels however, contain high amounts of alkali metals which get volatilized at high temperatures and forms salts with low melting points and thus condense on pipelines, reactor surfaces and may cause de-fluidization. A Low......-Temperature Circulating Fluidized Bed System (LTCFB) gasifier allows pyrolysis and gasification of biomass to occur at low temperatures thereby improving the retention of alkali and other ash species within the system and minimizing the amount of ash species in the product gas. In addition, the low reactor temperature...

  20. A scaled experimental study of control blade insertion dynamics in Pebble-Bed Fluoride-Salt-Cooled High-Temperature Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Buster, Grant C., E-mail: grant.buster@gmail.com; Laufer, Michael R.; Peterson, Per F.

    2016-07-15

    Highlights: • A granular dynamics scaling methodology is discussed. • Control blade insertion in a representative pebble-bed core is experimentally studied. • Control blade insertion forces and pebble displacements are experimentally measured. • X-ray tomography techniques are used to observe pebble displacement distributions. - Abstract: Direct control element insertion into a pebble-bed reactor core is proposed as a viable control system in molten-salt-cooled pebble-bed reactors. Unlike helium-cooled pebble-bed reactors, this reactor type uses spherical fuel elements with near-neutral buoyancy in the molten-salt coolant, thus reducing contact forces on the fuel elements. This study uses the X-ray Pebble Bed Recirculation Experiment facility to measure the force required to insert a control element directly into a scaled pebble-bed. The required control element insertion force, and therefore the contact force on fuel elements, is measured to be well below recommended limits. Additionally, X-ray tomography is used to observe how the direct insertion of a control element physically displaces spherical fuel elements. The tomography results further support the viability of direct control element insertion into molten-salt-cooled pebble-bed reactor cores.

  1. User's manual for ASTERIX-2: a two-dimensional modular-code system for the steady-state and xenon-transient analysis of a pebble-bed high-temperature reactor

    International Nuclear Information System (INIS)

    Lauer, A.; Schwiegk, H.J.; Wu, T.; Cowan, C.L.

    1982-03-01

    The ASTERIX modular code package was developed at KFA Laboratory-Juelich for the steady state and xenon transient analysis of a pebble bed high temperature reactor. The code package was implemented on the Stanford Linear Accelerator Center Computer in August, 1980, and a user's manual for the current version of the code, identified as ASTERIX-2, was prepared as a cooperative effort by KFA Laboratory and GE-ARSD. The material in the manual includes the requirements for accessing the program, a description of the major subroutines, a listing of the input options, and a listing of the input data for a sample problem. The material is provided in sufficient detail for the user to carry out a wide range of analyses from steady state operations to the xenon induced power transients in which the local xenon, temperature, buckling and control feedback effects have been incorporated in the problem solution

  2. 10 years of current generation in the AVR reactor. The high-temperature pebble-bed reactor - a hot tip for our future

    Energy Technology Data Exchange (ETDEWEB)

    Schenk, P [Arbeitsgemeinschaft Versuchs-Reaktor G.m.b.H., Juelich (Germany, F.R.); A G, Stadtwerke Duesseldorf [Germany, F.R.; Vereinigung Deutscher Elektrizitaetswerke e.V. (VDEW), Frankfurt am Main (Germany, F.R.)); Nehrling, H [Ministerium fuer Wirtschaft, Mittelstand und Verkehr des Landes Nordrhein-Westfalen, Duesseldorf (Germany, F.R.); Daeunert, U [Bundesministerium fuer Forschung und Technologie, Bonn-Bad Godesberg (Germany, F.R.); Schulten, R [Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.). Inst. fuer Reaktorentwicklung; Mattick, W [Brown, Boveri und Cie A.G., Mannheim (Germany, F.R.)

    1978-02-01

    On 17th December 1967, the experimental nuclear power plant (AVR) in Juelich supplied RWE network with power for the first time. With the start of the power operation of the first German high-temperature reactor (HTR), a milestone was reached in the development of this new and progressive line of construction. On the same day exactly 10 years later, the successful work with the hottest nuclear reactor in the world was reviewed in the presence of 15 associates of the Arbeitsgemeinschaft Versuchsreaktor (AVR) Ltd. and the personnel of the experimental nuclear power plant at a festival event in the main auditorium of the nuclear power plant at Juelich before some 300 guests from central and local government, the board of control, representatives of the population of the Dueren area and the town of Juelich, as well as bodies of the power producing industry.

  3. Temperature and pressure distributions in a 400 kW{sub t} fluidized bed straw gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Erguedenler, A.; Ghaly, A.E.; Hamdullahpur, F. [Technical Univ. of Nova Scotia, Halifax (Canada)

    1993-12-31

    The temperature and pressure distribution characteristics of a 400 kW (thermal) dual-distributor type fluidized bed straw gasifier were investigated. The effects of the bed height, equivalence ratio (actual air-fuel ratio:stoichiometric air-fuel ratio) and fluidization velocity on the temperature and pressure variations in the gasifier were studied. Generally, the bed temperature reached the steady state condition within 15--20 minutes. The average temperature of the dense bed ranged from 649{degrees}C to 875{degrees}C depending on the levels of operating parameters used. The bed temperature increased linearly with increases in the equivalence ratio, higher bed temperatures were observed with lower bed height and no clear trend for the bed temperature with respect to variations in fluidization velocity was observed. The bed height, equivalence ratio and fluidization velocity affected the pressure drop in the fluidized bed gasifier. Increasing the fluidization velocity and/or decreasing the equivalence ratio resulted in higher pressure drops in the dense bed and the freeboard regions whereas increasing the bed height increased the pressure drop only in the dense bed.

  4. Use of a fluidized bed combustor and thermogravimetric analyzer for the study of coal ignition temperature

    International Nuclear Information System (INIS)

    Ávila, Ivonete; Crnkovic, Paula M.; Luna, Carlos M.R.; Milioli, Fernando E.

    2017-01-01

    Highlights: • Coal ignition tests were conducted in a fluidized bed and thermogravimetric conditions. • The use of two different ignition criteria showed a similar coal ignition temperature. • Coal ignition temperature was obtained by the changes of gas concentrations in FBC. • Ignition temperatures were associated with the activation energy of coal combustion. - Abstract: Ignition experiments with two bituminous coals were carried out in an atmospheric bubbling fluidized bed combustor (FBC) and a thermogravimetric analyzer (TGA). In the FBC tests, the rapid increase in O_2, CO_2, and SO_2 concentrations is an indication of the coal ignition. In the TGA technique, the ignition temperature was determined by the evaluation of the TGA curves in both combustion and pyrolysis processes. Model-Free Kinetics was applied and the coal ignition temperatures were associated with changes in the activation energy values during the combustion process. The results show the coal with the lowest activation energy also showed the lowest ignition temperature, highest values of volatile content and a higher heating value. The application of two different ignition criteria (TGA and FBC) resulted in similar ignition temperatures. The FBC curves indicated the high volatile coal ignites in the freeboard, i.e. during the feeding in the reactor, whereas the low volatile coal ignites in the bed. Finally, the physicochemical characteristics of the investigated coal types were correlated with their reactivities for the prediction of the ignition temperatures behaviors under different operating conditions as those in FBC.

  5. Development of local heat transfer and pressure drop models for pebble bed high temperature gas-cooled reactor cores - HTR2008-58296

    International Nuclear Information System (INIS)

    McLaughlin, B.; Worsley, M.; Stainsby, R.; Grief, A.; Dennier, A.; Macintosh, S.; Van Heerden, E.

    2008-01-01

    This paper describes pressure drop and heat transfer coefficient predictions for a typical coolant flow within the core of a pebble bed reactor (PBR) by examining a representative group of pebbles remote from the reflector region. The three- dimensional steady state flow and heat transfer predictions utilized in this work are obtained from a computational fluid dynamics (CFD) model created in the commercial software ANSYS FLUENT TM . This work utilizes three RANS turbulence models and the Chilton-Colburn analogy for heat transfer. A methodology is included in this paper for creating a quality unstructured mesh with prismatic surface layers on a random arrangement of touching pebbles. The results of the model are validated by comparing them with the correlations of the German KTA rules for a PBR. (authors)

  6. Modelling of HTR (High Temperature Reactor Pebble-Bed 10 MW to Determine Criticality as A Variations of Enrichment and Radius of the Fuel (Kernel With the Monte Carlo Code MCNP4C

    Directory of Open Access Journals (Sweden)

    Hammam Oktajianto

    2014-12-01

    Full Text Available Gas-cooled nuclear reactor is a Generation IV reactor which has been receiving significant attention due to many desired characteristics such as inherent safety, modularity, relatively low cost, short construction period, and easy financing. High temperature reactor (HTR pebble-bed as one of type of gas-cooled reactor concept is getting attention. In HTR pebble-bed design, radius and enrichment of the fuel kernel are the key parameter that can be chosen freely to determine the desired value of criticality. This paper models HTR pebble-bed 10 MW and determines an effective of enrichment and radius of the fuel (Kernel to get criticality value of reactor. The TRISO particle coated fuel particle which was modelled explicitly and distributed in the fuelled region of the fuel pebbles using a Simple-Cubic (SC lattice. The pebble-bed balls and moderator balls distributed in the core zone using a Body-Centred Cubic lattice with assumption of a fresh fuel by the fuel enrichment was 7-17% at 1% range and the size of the fuel radius was 175-300 µm at 25 µm ranges. The geometrical model of the full reactor is obtained by using lattice and universe facilities provided by MCNP4C. The details of model are discussed with necessary simplifications. Criticality calculations were conducted by Monte Carlo transport code MCNP4C and continuous energy nuclear data library ENDF/B-VI. From calculation results can be concluded that an effective of enrichment and radius of fuel (Kernel to achieve a critical condition was the enrichment of 15-17% at a radius of 200 µm, the enrichment of 13-17% at a radius of 225 µm, the enrichments of 12-15% at radius of 250 µm, the enrichments of 11-14% at a radius of 275 µm and the enrichment of 10-13% at a radius of 300 µm, so that the effective of enrichments and radii of fuel (Kernel can be considered in the HTR 10 MW. Keywords—MCNP4C, HTR, enrichment, radius, criticality 

  7. Experimental measurement of variation of heat transfer coefficient and temperature gradients in 16'' deep fluidised beds

    International Nuclear Information System (INIS)

    Blacker, P.T.; McLain, D.R.

    1962-04-01

    The object of the experiments was to choose suitable particulate materials for a fluidised bed cooler, to test a deep fluidised bed for uniformity of heat transfer coefficient, and to explore the temperature distribution in a centrally heated annular fluidised bed. This memorandum records the techniques used and some of the practical aspects involved, together with the performance results obtained, for the assistance of other experimenters who may wish to use fluidised beds as a laboratory technique. Mathematical correlation of the results has not been attempted since some of the properties of the bed material were not known and to determine them was beyond the scope of the work programme. Rather, we have compared our results with those of other experimenters. Graphite tubes, for use in steady state thermal stress experiments, are to be heated by a graphite radiant heater situated in the bore and cooled on the outer surface. The tubes are 2 cm. bore, 8 cm. outside diameter and 48 cm. long. The outside temperature of the tubes is to be between 500 deg. C. and 1500 deg. C. It is estimated that the heat transfer rate required for fracture at the outer surface is 30 watts/cm 2 . This could readily be achieved by cooling with liquid metals, water or high velocity gas. However, serious problems of either materials compatibility or mechanical complexity make these undesirable. A water-cooled fluidised bed of compatible solids fluidised with nitrogen gas can overcome most of these problems and give heat transfer coefficients close to that required, vis. about 0.1 w/cm C . A coolant bed about 20'' long would be required and an annulus of about 2'' radial width round the specimen was considered to be practicable

  8. Experimental measurement of variation of heat transfer coefficient and temperature gradients in 16'' deep fluidised beds

    Energy Technology Data Exchange (ETDEWEB)

    Blacker, P T; McLain, D R [Reactor Development Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

    1962-04-15

    The object of the experiments was to choose suitable particulate materials for a fluidised bed cooler, to test a deep fluidised bed for uniformity of heat transfer coefficient, and to explore the temperature distribution in a centrally heated annular fluidised bed. This memorandum records the techniques used and some of the practical aspects involved, together with the performance results obtained, for the assistance of other experimenters who may wish to use fluidised beds as a laboratory technique. Mathematical correlation of the results has not been attempted since some of the properties of the bed material were not known and to determine them was beyond the scope of the work programme. Rather, we have compared our results with those of other experimenters. Graphite tubes, for use in steady state thermal stress experiments, are to be heated by a graphite radiant heater situated in the bore and cooled on the outer surface. The tubes are 2 cm. bore, 8 cm. outside diameter and 48 cm. long. The outside temperature of the tubes is to be between 500 deg. C. and 1500 deg. C. It is estimated that the heat transfer rate required for fracture at the outer surface is 30 watts/cm{sup 2}. This could readily be achieved by cooling with liquid metals, water or high velocity gas. However, serious problems of either materials compatibility or mechanical complexity make these undesirable. A water-cooled fluidised bed of compatible solids fluidised with nitrogen gas can overcome most of these problems and give heat transfer coefficients close to that required, vis. about 0.1 w/cm C . A coolant bed about 20'' long would be required and an annulus of about 2'' radial width round the specimen was considered to be practicable.

  9. Engineering solutions for a reflector change concept in the high-temperature reactor with pebble bed core and OTTO-fueling

    International Nuclear Information System (INIS)

    Kasper, K.J.

    1975-06-01

    In the field of reactor engineering an increasing tendency is visible towards a 'repairable reactor'. In the construction of the HTR with spherical fuel elements this fact should already be taken into account at an early stage. Additionally it is possible that in connection with the OTTO-fueling load conditions for the graphite reflector could result which are locally not far away from limiting values. Therefore the removability of the reflector is included in the reactor construction as an accompanying technical step of the physical lay-out of the core. The core arrangements, realized for HTR until recently, are discussed as well as the properties of the graphites used and the operating conditions in the reactors are stated. At the example of the PR 3,000 proposals are offered for the construction of a removable side and top reflector for a pebble bed reactor. Hereby a solution was found which, on one hand allows the changing of the reflector and on the other hand requires no significant increase of the costs for the reactor assembly. Moreover the requirements of reactor operation and of repairability are satisfied in an optimal manner. (orig.) [de

  10. High Maturity Is Not a Procrustean Bed

    Science.gov (United States)

    2014-07-01

    for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT In Greek mythology , Procrustes was a rogue smith and bandit who...Institute of Technology Jo Ann Lane, University of Southern California Supannika Koolmanojwong, University of Southern California Abstract. In Greek ... mythology , Procrustes was a rogue smith and bandit who invited travellers to rest in his “perfectly sized bed.” When they accepted, he forcibly bound

  11. Supersymmetry at high temperatures

    International Nuclear Information System (INIS)

    Das, A.; Kaku, M.

    1978-01-01

    We investigate the properties of Green's functions in a spontaneously broken supersymmetric model at high temperatures. We show that, even at high temperatures, we do not get restoration of supersymmetry, at least in the one-loop approximation

  12. Preliminary Neutronic Design of High Burnup OTTO Cycle Pebble Bed Reactor

    OpenAIRE

    Setiadipura, T; Irwanto, D; Zuhair, Zuhair

    2015-01-01

    The pebble bed type High Temperature Gas-cooled Reactor (HTGR) is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR) which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO) cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor ...

  13. Quasi-direct numerical simulation of a pebble bed configuration, Part-II: Temperature field analysis

    International Nuclear Information System (INIS)

    Shams, A.; Roelofs, F.; Komen, E.M.J.; Baglietto, E.

    2013-01-01

    Highlights: ► Quasi direct numerical simulations (q-DNSs) of a pebble bed configuration have been performed. ► This q-DNS database may serve as a reference for the validation of different turbulence modeling approaches. ► A wide range of qualitative and quantitative data throughout the computational domain has been generated. ► Results for mean, RMS of temperature and respective turbulent heat fluxes are extensively reported in this paper. -- Abstract: Good prediction of the flow and heat transfer phenomena in the pebble bed core of a high temperature reactor (HTR) is a challenge for available turbulence models, which still require to be validated. While experimental data are generally desirable in this validation process, due to the complex geometric configuration and measurement difficulties, a very limited amount of data is currently available. On the other hand, direct numerical simulation (DNS) is considered an accurate simulation technique, which may serve as an alternative for validating turbulence models. In the framework of the present study, quasi-direct numerical simulation (q-DNS) of a single face cubic centered pebble bed is performed, which will serve as a reference for the validation of different turbulence modeling approaches in order to perform calculations for a randomly arranged pebble bed. These simulations were performed at a Reynolds number of 3088, based on pebble diameter, with a porosity level of 0.42. Results related to flow field (mean, RMS and covariance of velocity) have been presented in Part-I, whereas, in the present article, we focus our attention to the analysis of the temperature field. A wide range of qualitative and quantitative data for the thermal field (mean, RMS and turbulent heat flux) has been generated

  14. Tracking channel bed resiliency in forested mountain catchments using high temporal resolution channel bed movement

    Science.gov (United States)

    Martin, Sarah E.; Conklin, Martha H.

    2018-01-01

    This study uses continuous-recording load cell pressure sensors in four, high-elevation (1500-1800 m), Sierra Nevada headwater streams to collect high-temporal-resolution, bedload-movement data for investigating the channel bed movement patterns within these streams for water years 2012-2014. Data show an annual pattern where channel bed material in the thalweg starts to build up in early fall, peaks around peak snow melt, and scours back to baseline levels during hydrograph drawdown and base flow. This pattern is punctuated by disturbance and recovery of channel bed material associated with short-term storm events. A conceptual model, linking sediment sources at the channel margins to patterns of channel bed fill and scour in the thalweg, is proposed building on the results of Martin et al. (2014). The material in the thalweg represents a balance between sediment supply from the channel margins and sporadic, conveyor-belt-like downstream transport in the thalweg. The conceptual model highlights not only the importance of production and transport rates but also that seasonal connectedness between the margins and thalweg is a key sediment control, determining the accumulation rate of sediment stores at the margins and the redistribution of sediment from margins to thalweg that feeds the conveyor belt. Disturbance and recovery cycles are observed at multiple temporal scales; but long term, the channel beds are stable, suggesting that the beds act as short-term storage for sediment but are in equilibrium interannually. The feasibility of use for these sensors in forested mountain stream environments is tested. Despite a high failure rate (50%), load cell pressure sensors show potential for high-temporal-resolution bedload measurements, allowing for the collection of channel bed movement data to move beyond time-integrated change measurements - where many of the subtleties of bedload movement patterns may be missed - to continuous and/or real-time measurements. This

  15. Study on Characteristic of Temperature Coefficient of Reactivity for Plutonium Core of Pebbled Bed Reactor

    Science.gov (United States)

    Zuhair; Suwoto; Setiadipura, T.; Bakhri, S.; Sunaryo, G. R.

    2018-02-01

    As a part of the solution searching for possibility to control the plutonium, a current effort is focused on mechanisms to maximize consumption of plutonium. Plutonium core solution is a unique case in the high temperature reactor which is intended to reduce the accumulation of plutonium. However, the safety performance of the plutonium core which tends to produce a positive temperature coefficient of reactivity should be examined. The pebble bed inherent safety features which are characterized by a negative temperature coefficient of reactivity must be maintained under any circumstances. The purpose of this study is to investigate the characteristic of temperature coefficient of reactivity for plutonium core of pebble bed reactor. A series of calculations with plutonium loading varied from 0.5 g to 1.5 g per fuel pebble were performed by the MCNPX code and ENDF/B-VII library. The calculation results show that the k eff curve of 0.5 g Pu/pebble declines sharply with the increase in fuel burnup while the greater Pu loading per pebble yields k eff curve declines slighter. The fuel with high Pu content per pebble may reach long burnup cycle. From the temperature coefficient point of view, it is concluded that the reactor containing 0.5 g-1.25 g Pu/pebble at high burnup has less favorable safety features if it is operated at high temperature. The use of fuel with Pu content of 1.5 g/pebble at high burnup should be considered carefully from core safety aspect because it could affect transient behavior into a fatal accident situation.

  16. High temperature refrigerator

    International Nuclear Information System (INIS)

    Steyert, W.A. Jr.

    1978-01-01

    A high temperature magnetic refrigerator is described which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle the working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir. The magnetic refrigeration cycle operates at an efficiency 70% of Carnot

  17. Fusion blanket high-temperature heat transfer

    International Nuclear Information System (INIS)

    Fillo, J.A.

    1983-01-01

    Deep penetration of 14 MeV neutrons makes two-temperature region blankets feasible. A relatively low-temperature (approx. 300 0 C) metallic structure is the vacuum/coolant pressure boundary, while the interior of the blanket, which is a simple packed bed of nonstructural material, operates at very high temperatures (>1000 0 C). The water-cooled shell structure is thermally insulated from the steam-cooled interior. High-temperature steam can dramatically increase the efficiency of electric power generation, as well as produce hydrogen and oxygen-based synthetic fuels at high-efficiency

  18. High-temperature superconductivity

    International Nuclear Information System (INIS)

    Lynn, J.W.

    1990-01-01

    This book discusses development in oxide materials with high superconducting transition temperature. Systems with Tc well above liquid nitrogen temperature are already a reality and higher Tc's are anticipated. The author discusses how the idea of a room-temperature superconductor appears to be a distinctly possible outcome of materials research

  19. Highly efficient high temperature electrolysis

    DEFF Research Database (Denmark)

    Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard

    2008-01-01

    High temperature electrolysis of water and steam may provide an efficient, cost effective and environmentally friendly production of H-2 Using electricity produced from sustainable, non-fossil energy sources. To achieve cost competitive electrolysis cells that are both high performing i.e. minimum...... internal resistance of the cell, and long-term stable, it is critical to develop electrode materials that are optimal for steam electrolysis. In this article electrolysis cells for electrolysis of water or steam at temperatures above 200 degrees C for production of H-2 are reviewed. High temperature...... electrolysis is favourable from a thermodynamic point of view, because a part of the required energy can be supplied as thermal heat, and the activation barrier is lowered increasing the H-2 production rate. Only two types of cells operating at high temperature (above 200 degrees C) have been described...

  20. High temperature fusion reactor design

    International Nuclear Information System (INIS)

    Harkness, S.D.; dePaz, J.F.; Gohar, M.Y.; Stevens, H.C.

    1979-01-01

    Fusion energy may have unique advantages over other systems as a source for high temperature process heat. A conceptual design of a blanket for a 7 m tokamak reactor has been developed that is capable of producing 1100 0 C process heat at a pressure of approximately 10 atmospheres. The design is based on the use of a falling bed of MgO spheres as the high temperature heat transfer system. By preheating the spheres with energy taken from the low temperature tritium breeding part of the blanket, 1086 MW of energy can be generated at 1100 0 C from a system that produces 3000 MW of total energy while sustaining a tritium breeding ratio of 1.07. The tritium breeding is accomplished using Li 2 O modules both in front of (6 cm thick) and behind (50 cm thick) the high temperature ducts. Steam is used as the first wall and front tritium breeding module coolant while helium is used in the rear tritium breeding region. The system produces 600 MW of net electricity for use on the grid

  1. Temperature Measurements to Characterize Dispersion Within Pressure Swing Adsorption (PSA) Beds

    National Research Council Canada - National Science Library

    Buettner, L

    1997-01-01

    ...) as the feed contaminant and air as the carrier. In-bed, vapor-phase concentrations at each axial position were measured and correlated to the magnitude of the temperature swings during a cycle...

  2. Hybrid Molten Bed Gasifier for High Hydrogen Syngas Production

    Energy Technology Data Exchange (ETDEWEB)

    Rue, David [Gas Technology Institute, Des Plaines, IL (United States)

    2017-05-23

    was stable over the full oxygen to fuel firing range (0.8 to 1.05 of fuel gas stoichiometry) and with all fuel gases (natural gas and two syngas compositions), with steam, and without steam. The lower Btu content of the syngases presented no combustion difficulties. The molten bed was stable throughout testing. The molten bed was easily established as a bed of molten glass. As the composition changed from glass cullet to cullet with slag, no instabilities were encountered. The bed temperature and product syngas temperature remained stable throughout testing, demonstrating that the bed serves as a good heat sink for the gasification process. Product syngas temperature measured above the bed was stable at ~1600ºF. Testing found that syngas quality measured as H2/CO ratio increased with decreasing oxygen to fuel gas stoichiometric ratio, higher steam to inlet carbon ratio, higher temperature, and syngas compared with natural gas. The highest H2/CO ratios achieved were in the range of 0.70 to 0.78. These values are well below the targets of 1.5 to 2.0 that were expected and were predicted by modeling. The team, however, is encouraged that the HMB process can and will achieve H2/CO ratios up to 2.0. Changes needed include direct injection of coal into the molten bed of slag to prevent coal particle bypass into the product gas stream, elevation of the molten bed temperature to approximately 2500ºF, and further decrease of the oxygen to fuel gas ratio to well below the 0.85 minimum ratio used in the testing in this project.

  3. Parametric study for high conversion pebble bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Teuchert, E.; Ruetten, H. J.

    1975-06-15

    Tables are presented of fuel cycle costs, conversion ratios and accompanying variations in fuel element designs for a 3,00 MWth high conversion pebble bed reactor with initial high enriched uranium/thorium cycle and subsequent recycling of U-233, Pu-239 and Pu-241.

  4. Numerical study on influences of bed resettling, breeding zone orientation, and purge gas on temperatures in solid breeders

    Energy Technology Data Exchange (ETDEWEB)

    Van Lew, Jon T., E-mail: jtvanlew@fusion.ucla.edu; Ying, Alice; Abdou, Mohamed

    2016-11-01

    Highlights: • Volume-conserving pebble fragmentation model in DEM to study thermomechanical responses to crushed pebbles in ensembles. • Parametric studies of ITER-relevant pebble beds with coupled CFD-DEM models. • Finding breeder temperatures are complex functions of orientation, fragmentation size, and packing fraction. • Recommendations of breeder unit orientation are given in terms of material selection. - Abstract: We apply coupled computational fluid dynamics and discrete element method (CFD-DEM) modeling tools with new numerical implementations of pebble fragmentation to study the combined effects of granular crushing and ensemble restructuring, granular fragment size, and initial packing for different breeder volume configurations. In typical solid breeder modules, heat removal from beds relies on maintaining pebble–pebble and pebble–wall contact integrity. However, contact is disrupted when an ensemble responds to individually crushed pebbles. Furthermore, restructuring of metastable packings after crushing events are, in part, dependent on gravity forces acting upon the pebbles. We investigate two representative pebble bed configurations under constant volumetric heat sources; modeling heat removed from beds via inter-particle conduction, purge gas convection, and contact between pebble beds and containers. In one configuration, heat is removed from at walls oriented parallel to the gravity vector (no gap formation possible); in the second, heat is removed at walls perpendicular to gravity, allowing for the possibility of gap formation between bed and wall. Judging beds on increase in maximum temperatures as a function of crushed pebble amount, we find that both pebble bed configurations to have advantageous features that manifest at different stages of pebble crushing. However, all configurations benefit from achieving high initial packing fractions.

  5. High Power Fiber Laser Test Bed

    Data.gov (United States)

    Federal Laboratory Consortium — This facility, unique within DoD, power-combines numerous cutting-edge fiber-coupled laser diode modules (FCLDM) to integrate pumping of high power rare earth-doped...

  6. High temperature battery. Hochtemperaturbatterie

    Energy Technology Data Exchange (ETDEWEB)

    Bulling, M.

    1992-06-04

    To prevent heat losses of a high temperature battery, it is proposed to make the incoming current leads in the area of their penetration through the double-walled insulating housing as thermal throttle, particularly spiral ones.

  7. The high-temperature reactor

    International Nuclear Information System (INIS)

    Kirchner, U.

    1991-01-01

    The book deals with the development of the German high-temperature reactor (pebble-bed), the design of a prototype plant and its (at least provisional) shut-down in 1989. While there is a lot of material on the HTR's competitor, the fast breeder, literature is very incomplete on HTRs. The author describes HTR's history as a development which was characterised by structural divergencies but not effectively steered and monitored. There was no project-oriented 'community' such as there was for the fast breeder. Also, the new technology was difficult to control there were situations where no one quite knew what was going on. The technical conditions however were not taken as facts but as a basis for interpretation, wishes and reservations. The HTR gives an opportunity to consider the conditions under which large technical projects can be carried out today. (orig.) [de

  8. High temperature structural silicides

    International Nuclear Information System (INIS)

    Petrovic, J.J.

    1997-01-01

    Structural silicides have important high temperature applications in oxidizing and aggressive environments. Most prominent are MoSi 2 -based materials, which are borderline ceramic-intermetallic compounds. MoSi 2 single crystals exhibit macroscopic compressive ductility at temperatures below room temperature in some orientations. Polycrystalline MoSi 2 possesses elevated temperature creep behavior which is highly sensitive to grain size. MoSi 2 -Si 3 N 4 composites show an important combination of oxidation resistance, creep resistance, and low temperature fracture toughness. Current potential applications of MoSi 2 -based materials include furnace heating elements, molten metal lances, industrial gas burners, aerospace turbine engine components, diesel engine glow plugs, and materials for glass processing

  9. Effects of high salinity wastewater on methanogenic sludge bed systems

    NARCIS (Netherlands)

    Ismail, S.; Gonzalez-Contreras, P.A.; Jeison, D.A.; Lier, van J.B.

    2008-01-01

    The attainable loading potentials of anaerobic sludge bed systems are strongly dependent on the growth of granular biomass with a particular wastewater. Experiments were conducted to determine the effects of high salinity wastewater on the biological and physical properties of methanogenic sludge.

  10. Thermal conductivity and diffusivity of Permian Basin bedded salt at elevated pressure and temperature

    International Nuclear Information System (INIS)

    Durham, W.B.; Boro, C.O.; Beiriger, J.M.; Montan, D.N.

    1983-10-01

    Measurements of thermal conductivity and diffusivity were made on five core samples of bedded rock salt from the Permian Basin in Texas to determine its suitability as an underground nuclear waste repository. The sample size was 100 mm in diameter by 250 mm in length. Measurements were conducted under confining pressures ranging from 3.8 to 31.0 MPa and temperatures from room temperature to 473 K. Conductivity showed no dependence on confining pressure but evidenced a monotonic, negative temperature dependence. Four of the five samples showed conductivities clustered in a range of 5.6 +- 0.5 W/m.K at room temperature, falling to 3.6 +- 0.3 W/m.K at 473 K. These values are approximately 20% below those for pure halite, reflecting perhaps the 5 to 20%-nonhalite component of the samples. Diffusivity also showed a monotonic, negative temperature dependence, with four of the five samples clustered in a range of 2.7 +- 0.4 x 10 -6 m 2 /s at room temperature, and 1.5 +- 0.3 x 10 -6 m 2 /s at 473 K, all roughly 33% below the values for pure halite. One sample showed an unusually high conductivity (it also had the highest diffusivity), about 20% higher than the others; and one sample showed an unusually low diffusivity (it also had the lowest conductivity), roughly a factor of 2 lower than the others. 27 references, 8 figures, 4 tables

  11. Addition of Bacillus sp. inoculums in bedding for swine on a pilot scale: effect on microbial population and bedding temperature.

    Science.gov (United States)

    Corrêa, E K; Ulguim, R R; Corrêa, L B; Castilhos, D D; Bianchi, I; Gil-Turnes, C; Lucia, T

    2012-10-01

    Thermal and microbiological characteristics of beddings for swine were compared according to their depth and of addition of inoculums. Bedding was added to boxes at 0.25 (25D) and 0.50 m (50D), with three treatments: control (no inoculums); T1, with 250 g of Bacillus cereus var. toyoii at 8.4 × 10(7) CFU; and T2, with 250 g of a pool of B. subtilis, Bacillus licheniformis and Bacillus polymyxa at 8.4 × 10(7) CFU (250 g for 25D and 500 g for 50D). Mean temperatures were 28.5 ± 3.9 at the surface and 35.2 ± 8.9 inside the beddings. The most probable number (MPN) of thermophilic bacteria was higher for T1 and T2 than for the control (P<0.05). The MPN of thermophilic bacteria and fungi was greater for D50 than for D25 (P<0.05). The use of 25D without inoculums is recommended due to the reduction of thermophilic microbiota. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. High temperature reaction kinetics

    International Nuclear Information System (INIS)

    Jonah, C.D.; Beno, M.F.; Mulac, W.A.; Bartels, D.

    1985-01-01

    During the last year the dependence of the apparent rate of OD + CO on water pressure was measured at 305, 570, 865 and 1223 K. An explanation was found and tested for the H 2 O dependence of the apparent rate of OH(OD) + CO at high temperatures. The isotope effect for OH(D) with CO was determined over the temperature range 330 K to 1225 K. The reason for the water dependence of the rate of OH(OD) + CO near room temperatures has been investigated but no clear explanation has been found. 1 figure

  13. High-temperature superconductivity

    International Nuclear Information System (INIS)

    Ginzburg, V.L.

    1987-07-01

    After a short account of the history of experimental studies on superconductivity, the microscopic theory of superconductivity, the calculation of the control temperature and its possible maximum value are presented. An explanation of the mechanism of superconductivity in recently discovered superconducting metal oxide ceramics and the perspectives for the realization of new high-temperature superconducting materials are discussed. 56 refs, 2 figs, 3 tabs

  14. High temperature pipeline design

    Energy Technology Data Exchange (ETDEWEB)

    Greenslade, J.G. [Colt Engineering, Calgary, AB (Canada). Pipelines Dept.; Nixon, J.F. [Nixon Geotech Ltd., Calgary, AB (Canada); Dyck, D.W. [Stress Tech Engineering Inc., Calgary, AB (Canada)

    2004-07-01

    It is impractical to transport bitumen and heavy oil by pipelines at ambient temperature unless diluents are added to reduce the viscosity. A diluted bitumen pipeline is commonly referred to as a dilbit pipeline. The diluent routinely used is natural gas condensate. Since natural gas condensate is limited in supply, it must be recovered and reused at high cost. This paper presented an alternative to the use of diluent to reduce the viscosity of heavy oil or bitumen. The following two basic design issues for a hot bitumen (hotbit) pipeline were presented: (1) modelling the restart problem, and, (2) establishing the maximum practical operating temperature. The transient behaviour during restart of a high temperature pipeline carrying viscous fluids was modelled using the concept of flow capacity. Although the design conditions were hypothetical, they could be encountered in the Athabasca oilsands. It was shown that environmental disturbances occur when the fluid is cooled during shut down because the ground temperature near the pipeline rises. This can change growing conditions, even near deeply buried insulated pipelines. Axial thermal loads also constrain the design and operation of a buried pipeline as higher operating temperatures are considered. As such, strain based design provides the opportunity to design for higher operating temperature than allowable stress based design methods. Expansion loops can partially relieve the thermal stress at a given temperature. As the design temperature increase, there is a point at which above grade pipelines become attractive options, although the materials and welding procedures must be suitable for low temperature service. 3 refs., 1 tab., 10 figs.

  15. Pressure drop in packed beds of spherical particles at ambient and elevated air temperatures

    Directory of Open Access Journals (Sweden)

    Pešić Radojica

    2015-01-01

    Full Text Available The aim of this work was the experimental investigation of the particle friction factor for air flow through packed bed of particles at ambient and elevated temperatures. The experiments were performed by measuring the pressure drop across the packed bed, heated to the desired temperature by hot air. Glass spherical particles of seven different diameters were used. The temperature range of the air flowing through the packed bed was from 20ºC to 350ºC and the bed voidages were from 0.3574 to 0.4303. The obtained results were correlated using a number of available literature correlations. The overall best fit of all of the experimental data was obtained using Ergun [1] equation, with mean absolute deviation of 10.90%. Ergun`s equation gave somewhat better results in correlating the data at ambient temperature with mean absolute deviation of 9.77%, while correlation of the data at elevated temperatures gave mean absolute deviation of 12.38%. The vast majority of the correlations used gave better results when applied to ambient temperature data than to the data at elevated temperatures. Based on the results obtained, Ergun [1] equation is proposed for friction factor calculation both at ambient and at elevated temperatures. [Projekat Ministarstva nauke Republike Srbije, br. ON172022

  16. Ultra-high temperature direct propulsion

    International Nuclear Information System (INIS)

    Araj, K.J.; Slovik, G.; Powell, J.R.; Ludewig, H.

    1987-01-01

    Potential advantages of ultra-high exhaust temperature (3000 K - 4000 K) direct propulsion nuclear rockets are explored. Modifications to the Particle Bed Reactor (PBR) to achieve these temperatures are described. Benefits of ultra-high temperature propulsion are discussed for two missions - orbit transfer (ΔV = 5546 m/s) and interplanetary exploration (ΔV = 20000 m/s). For such missions ultra-high temperatures appear to be worth the additional complexity. Thrust levels are reduced substantially for a given power level, due to the higher enthalpy caused by partial disassociation of the hydrogen propellant. Though technically challenging, it appears potentially feasible to achieve such ultra high temperatures using the PBR

  17. Advanced control system for temperature control in the pressurized fluid bed of Escatron Thermal Plant Power; Sistema de Control Avanzado para Control de la Temperatura del Lecho Fluido a Presion de la Central Termica de Escatron

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    In the P. F-B. C a small problem appears, particularly in Escatron the bed temperature gradient is very high. Such gradient very occasionally reaches 50 degree centigree in a same plane. With the reduction of bed difference of temperature, the average bed temperature could be increased with the result steam cycle benefit, at the same time combustion gases would go at a higher temperature to the gas turbine, increasing therefore its performance. The SCAP system will allow to face the resolution of the injection of combustible problem and in this manner achieve the homogenization of bed temperature in Escatron PFBC Thermal Power Station. (Author)

  18. High temperature storage loop :

    Energy Technology Data Exchange (ETDEWEB)

    Gill, David Dennis; Kolb, William J.

    2013-07-01

    A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort

  19. High flux Particle Bed Reactor systems for rapid transmutation of actinides and long lived fission products

    International Nuclear Information System (INIS)

    Powell, J.; Ludewig, H.; Maise, G.; Steinberg, M.; Todosow, M.

    1993-01-01

    An initial assessment of several actinide/LLFP burner concepts based on the Particle Bed Reactor (PBR) is described. The high power density/flux level achievable with the PBR make it an attractive candidate for this application. The PBR based actinide burner concept also possesses a number of safety and economic benefits relative to other reactor based transmutation approaches including a low inventory of radionuclides, and high integrity, coated fuel particles which can withstand extremely high in temperatures while retaining virtually all fission products. In addition the reactor also posesses a number of ''engineered safety features,'' which, along with the use of high temperature capable materials further enhance its safety characteristics

  20. High temperature niobium alloys

    International Nuclear Information System (INIS)

    Wojcik, C.C.

    1991-01-01

    Niobium alloys are currently being used in various high temperature applications such as rocket propulsion, turbine engines and lighting systems. This paper presents an overview of the various commercial niobium alloys, including basic manufacturing processes, properties and applications. Current activities for new applications include powder metallurgy, coating development and fabrication of advanced porous structures for lithium cooled heat pipes

  1. High Temperature Electrolysis

    DEFF Research Database (Denmark)

    Elder, Rachael; Cumming, Denis; Mogensen, Mogens Bjerg

    2015-01-01

    High temperature electrolysis of carbon dioxide, or co-electrolysis of carbon dioxide and steam, has a great potential for carbon dioxide utilisation. A solid oxide electrolysis cell (SOEC), operating between 500 and 900. °C, is used to reduce carbon dioxide to carbon monoxide. If steam is also i...

  2. High temperature thermometric phosphors

    Science.gov (United States)

    Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.y) wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

  3. Temperature effects on biohydrogen production in a granular sludge bed induced by activated carbon carriers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kuo-Shing [Department of Safety Health and Environmental Engineering, Chung tai Institute of Health Sciences and Technology, Taichung (China); Lin, Ping-Jei [Department of Chemical Engineering, Feng Chia University, Taichung (China); Chang, Jo-Shu [Department of Chemical Engineering, National Cheng Kung University, Tainan (China)

    2006-03-15

    Temperature effects on H{sub 2} production performance of a novel carrier-induced granular sludge bed (CIGSB) reactor were investigated. Using sucrose-based synthetic wastewater as the feed, the CIGSB system was operated at 30-45 {sup 0}C to identify the optimal working temperature. It was found that H{sub 2} production was the most efficient at 40 {sup 0}C, especially when it was operated at a low hydraulic retention time (HRT) of 0.5h. The overall maximal hydrogen production rate and yield were 7.66l/h/l and 3.88mol H{sub 2}/mol sucrose, respectively, both of them occurred at 40 {sup 0}C. The biomass content tended to decrease as the temperature was increased, suggesting that granular sludge formation may be inhibited at high temperatures. However, increasing temperature gave better specific H{sub 2} production rate, signifying that the average cellular activity for H{sub 2} production may be enhanced as the temperature was increased. The H{sub 2} yield and gas phase H{sub 2} content did not vary considerably regardless of changes in temperature and HRT. This reflects that the CIGSB was a relatively stable H{sub 2}-producing system. The major soluble products from hydrogen fermentation were butyric acid and acetic acid, accounting for 46+-3% and 28+-2% of total soluble microbial products (SMP), respectively. Thus, the dominant H{sub 2} producers in the mixed culture belonged to acidogenic bacteria that underwent butyrate-type fermentation. (author)

  4. High temperature materials characterization

    Science.gov (United States)

    Workman, Gary L.

    1990-01-01

    A lab facility for measuring elastic moduli up to 1700 C was constructed and delivered. It was shown that the ultrasonic method can be used to determine elastic constants of materials from room temperature to their melting points. The ease in coupling high frequency acoustic energy is still a difficult task. Even now, new coupling materials and higher power ultrasonic pulsers are being suggested. The surface was only scratched in terms of showing the full capabilities of either technique used, especially since there is such a large learning curve in developing proper methodologies to take measurements into the high temperature region. The laser acoustic system does not seem to have sufficient precision at this time to replace the normal buffer rod methodology.

  5. High temperature materials

    International Nuclear Information System (INIS)

    2003-01-01

    The aim of this workshop is to share the needs of high temperature and nuclear fuel materials for future nuclear systems, to take stock of the status of researches in this domain and to propose some cooperation works between the different research organisations. The future nuclear systems are the very high temperature (850 to 1200 deg. C) gas cooled reactors (GCR) and the molten salt reactors (MSR). These systems include not only the reactor but also the fabrication and reprocessing of the spent fuel. This document brings together the transparencies of 13 communications among the 25 given at the workshop: 1) characteristics and needs of future systems: specifications, materials and fuel needs for fast spectrum GCR and very high temperature GCR; 2) high temperature materials out of neutron flux: thermal barriers: materials, resistance, lifetimes; nickel-base metal alloys: status of knowledge, mechanical behaviour, possible applications; corrosion linked with the gas coolant: knowledge and problems to be solved; super-alloys for turbines: alloys for blades and discs; corrosion linked with MSR: knowledge and problems to be solved; 3) materials for reactor core structure: nuclear graphite and carbon; fuel assembly structure materials of the GCR with fast neutron spectrum: status of knowledge and ceramics and cermets needs; silicon carbide as fuel confinement material, study of irradiation induced defects; migration of fission products, I and Cs in SiC; 4) materials for hydrogen production: status of the knowledge and needs for the thermochemical cycle; 5) technologies: GCR components and the associated material needs: compact exchangers, pumps, turbines; MSR components: valves, exchangers, pumps. (J.S.)

  6. High temperature radioisotope capsule

    International Nuclear Information System (INIS)

    Bradshaw, G.B.

    1976-01-01

    A high temperature radioisotope capsule made up of three concentric cylinders, with the isotope fuel located within the innermost cylinder is described. The innermost cylinder has hemispherical ends and is constructed of a tantalum alloy. The intermediate cylinder is made of a molybdenum alloy and is capable of withstanding the pressure generated by the alpha particle decay of the fuel. The outer cylinder is made of a platinum alloy of high resistance to corrosion. A gas separates the innermost cylinder from the intermediate cylinder and the intermediate cylinder from the outer cylinder

  7. High-temperature uncertainty

    International Nuclear Information System (INIS)

    Timusk, T.

    2005-01-01

    Recent experiments reveal that the mechanism responsible for the superconducting properties of cuprate materials is even more mysterious than we thought. Two decades ago, Georg Bednorz and Alex Mueller of IBM's research laboratory in Zurich rocked the world of physics when they discovered a material that lost all resistance to electrical current at the record temperature of 36 K. Until then, superconductivity was thought to be a strictly low-temperature phenomenon that required costly refrigeration. Moreover, the IBM discovery - for which Bednorz and Mueller were awarded the 1987 Nobel Prize for Physics - was made in a ceramic copper-oxide material that nobody expected to be particularly special. Proposed applications for these 'cuprates' abounded. High-temperature superconductivity, particularly if it could be extended to room temperature, offered the promise of levitating trains, ultra-efficient power cables, and even supercomputers based on superconducting quantum interference devices. But these applications have been slow to materialize. Moreover, almost 20 years on, the physics behind this strange state of matter remains a mystery. (U.K.)

  8. Low-temperature nitriding of austenitic steel in a vibrofluidized bed

    Science.gov (United States)

    Baraz, V. R.; Grachev, S. V.

    1999-11-01

    The prospects for use of a vibrofluidized bed (VFB) for low-temperature nitrogen saturation of high-strength austenitic steel based on Cr-Ni-Mn (12Kh17N8G2S2MF) are considered. The positive effect of preliminary plastic deformation on the intensity of nitriding is described. The temperature and time parameters of nitriding in a VFB for strain-aging austenitic steel 12Kh17N8G2S2MF are shown to be adequate for the regimes of the final heat-treatment operation of aging. This creates the possibility of combining the operations of surface alloying and strain aging into a single cycle. This combined treatment increases substantially the resistance of the steel to cyclic loads while preserving the strength parameters. It is shown that the presented method of low-temperature nitriding in a VFB is expedient for improving the service characteristics of austenitic steel 12Kh17N8G2S2MF used for production of force springs of automobile brake systems.

  9. High Temperature Piezoelectric Drill

    Science.gov (United States)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom

    2012-01-01

    Venus is one of the planets in the solar systems that are considered for potential future exploration missions. It has extreme environment where the average temperature is 460 deg C and its ambient pressure is about 90 atm. Since the existing actuation technology cannot maintain functionality under the harsh conditions of Venus, it is a challenge to perform sampling and other tasks that require the use of moving parts. Specifically, the currently available electromagnetic actuators are limited in their ability to produce sufficiently high stroke, torque, or force. In contrast, advances in developing electro-mechanical materials (such as piezoelectric and electrostrictive) have enabled potential actuation capabilities that can be used to support such missions. Taking advantage of these materials, we developed a piezoelectric actuated drill that operates at the temperature range up to 500 deg C and the mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) configuration. The detailed results of our study are presented in this paper

  10. Effect of temperature in fluidized bed fast pyrolysis of biomass: oil quality assessment in test units

    NARCIS (Netherlands)

    Westerhof, Roel Johannes Maria; Brilman, Derk Willem Frederik; van Swaaij, Willibrordus Petrus Maria; Kersten, Sascha R.A.

    2010-01-01

    Pine wood was pyrolyzed in a 1 kg/h fluidized bed fast pyrolysis reactor that allows a residence time of pine wood particles up to 25 min. The reactor temperature was varied between 330 and 580 °C to study the effect on product yields and oil composition. Apart from the physical−chemical analysis, a

  11. Performance and metallography of a uranium tritide bed operated at elevated temperatures and tritium pressures

    International Nuclear Information System (INIS)

    Mote, M.W. Jr.; Mintz, J.M.

    1986-12-01

    A uranium gettering bed was cycled between room temperature/zero pressure and 600C/275 psi (D 2 ) for 210 cycles over a period of 8 months. Metallographic examination of the hardware revealed an acceptable amount of reaction between the uranium and the stainless steel container. This exposure is estimated to represent about ten years of normal use

  12. High temperature materials and mechanisms

    CERN Document Server

    2014-01-01

    The use of high-temperature materials in current and future applications, including silicone materials for handling hot foods and metal alloys for developing high-speed aircraft and spacecraft systems, has generated a growing interest in high-temperature technologies. High Temperature Materials and Mechanisms explores a broad range of issues related to high-temperature materials and mechanisms that operate in harsh conditions. While some applications involve the use of materials at high temperatures, others require materials processed at high temperatures for use at room temperature. High-temperature materials must also be resistant to related causes of damage, such as oxidation and corrosion, which are accelerated with increased temperatures. This book examines high-temperature materials and mechanisms from many angles. It covers the topics of processes, materials characterization methods, and the nondestructive evaluation and health monitoring of high-temperature materials and structures. It describes the ...

  13. High temperature superconductors

    CERN Document Server

    Paranthaman, Parans

    2010-01-01

    This essential reference provides the most comprehensive presentation of the state of the art in the field of high temperature superconductors. This growing field of research and applications is currently being supported by numerous governmental and industrial initiatives in the United States, Asia and Europe to overcome grid energy distribution issues. The technology is particularly intended for densely populated areas. It is now being commercialized for power-delivery devices, such as power transmission lines and cables, motors and generators. Applications in electric utilities include current limiters, long transmission lines and energy-storage devices that will help industries avoid dips in electric power.

  14. Experimental Simulation of Methane Hydrate Extraction at High Pressure Conditions: Influence of the Sediment Bed

    Science.gov (United States)

    Agudo, J. R.; Park, J.; Luzi, G.; Williams, M.; Rauh, C.; Wierschem, A.; Delgado, A.

    2017-10-01

    Being a clean alternative to other fossil fuels, Methane Hydrate (MH) is currently considered as one of the most important potential sources for hydrocarbon fuels [1]. In addition, the high energy density of MH and its stability at higher temperatures as compared to LNG (Liquefied Natural Gas) makes MH a potential greener method for energy transportation. At the same time, the low thermodynamic stability of MH strongly questions the future exploitation of gas hydrate deposits, turning its extraction into a possible geohazard [2]. Fluctuations in pressure, temperature, salinity, degree of saturation or sediment bed properties may cause methane gas release from the water lattice. We experimentally study the influence of the sediment bed geometry during formation-dissociation of MH. For this purpose, MH is synthesized within regular substrates in a 93 cm3 high pressure vessel. The regular substrates are triangular and quadratic arrangements of identical glass spheres with a diameter of 2 and 5 mm, respectively. MH formation within regular substrate reduces the possibility of spontaneous nucleation to a unique geometrical configuration. This fact permits us to characterize the kinetics of MH formation-dissociation as a function of the sediment bed geometry. Preliminary experimental results reveal a strong dependence of MH formation on the geometry of the regular substrate. For instance, under the same pressure and temperature, the kinetics of MH production is found to change by a factor 3 solely depending on the substrate symmetry, i.e. triangular or quadratic.

  15. Gasification of high ash, high ash fusion temperature bituminous coals

    Science.gov (United States)

    Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

    2015-11-13

    This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

  16. High temperature interface superconductivity

    International Nuclear Information System (INIS)

    Gozar, A.; Bozovic, I.

    2016-01-01

    Highlight: • This review article covers the topic of high temperature interface superconductivity. • New materials and techniques used for achieving interface superconductivity are discussed. • We emphasize the role played by the differences in structure and electronic properties at the interface with respect to the bulk of the constituents. - Abstract: High-T_c superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-T_c Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both ‘passive’ hetero-structures as well as surface-induced effects by external gating are discussed. We conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

  17. High temperature metallic recuperator

    Science.gov (United States)

    Ward, M. E.; Solmon, N. G.; Smeltzer, C. E.

    1981-06-01

    An industrial 4.5 MM Btu/hr axial counterflow recuperator, fabricated to deliver 1600 F combustion air, was designed to handle rapid cyclic loading, a long life, acceptable costs, and a low maintenance requirement. A cost benefit anlysis of a high temperature waste heat recovery system utilizing the recurperator and components capable of 1600 F combustion air preheat shows that this system would have a payback period of less than two years. Fifteen companies and industrial associations were interviewed and expressed great interest in recuperation in large energy consuming industries. Determination of long term environmental effects on candidate recuperator tubing alloys was completed. Alloys found to be acceptable in the 2200 F flue gas environment of a steel billet reheat furnace, were identified.

  18. High Temperature Particle Filtration Technology; TOPICAL

    International Nuclear Information System (INIS)

    Besmann, T.M.

    2001-01-01

    High temperature filtration can serve to improve the economic, environmental, and energy performance of chemical processes. This project was designed to evaluate the stability of filtration materials in the environments of the production of dimethyldichlorosilane (DDS). In cooperation with Dow Corning, chemical environments for the fluidized bed reactor where silicon is converted to DDS and the incinerator where vents are cornbusted were characterized. At Oak Ridge National Laboratory (ORNL) an exposure system was developed that could simulate these two environments. Filter samples obtained from third parties were exposed to the environments for periods up to 1000 hours. Mechanical properties before and after exposure were determined by burst-testing rings of filter material. The results indicated that several types of filter materials would likely perform well in the fluid bed environment, and two materials would be good candidates for the incinerator environment

  19. Report on research and development achievements in fiscal 1980 in Sunshine Project. Development of a high-temperature bed drilling technology (Research and development of bit materials); 1980 nendo koon chiso kussaku gijutsu no kaihatsu seika hokokusho. Bit zairyo no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1981-03-01

    Development is made on bit materials that can efficiently drill high-temperature ground bed to 3,000 to 5,000 m under geothermal conditions of 350 degrees C and 400 kg/cm{sup 2}. Alloy composition excellent in corrosion resistance, oxidation resistance, high-temperature hardness, and repulsion resistance without decreasing damage resistance lower than the existing products is Cr{sub 3}C{sub 2} amount of 1%, WC of 2.5 microns, and Co/(Co + Ni) of 50%. Dispersion strengthening is most suitable for a metallurgically sintered powder cutter. Adding carbide of 5% by volume or metal as dispersion strengthening particles enhances hardness almost without damaging tenacity. Compression yield has also increased. Good dispersion strengthened materials include W and WC. On cutter materials for rock drilling bits used under severe conditions of high temperatures, high pressures, and corrosion environment, natures nearly close to the target were provided, and prospect for shape provision was obtained. These natures include mechanical properties at elevated temperatures, corrosion and wear resistance, an inside strengthening method, and a surface hardening method. Dispersion strengthening by adding micro fine hard powder to the inside strengthening method was used to have obtained the intended achievement. Positioning of the metallurgically sintered powder was made clear. (NEDO)

  20. Corn Drying with Zeolite in The Fluidized Bed Dryer under Medium Temperature

    Directory of Open Access Journals (Sweden)

    Mohamad Djaeni

    2013-08-01

    Full Text Available Drying is an important step to find high quality of corn. Based on Standard of National Industry, populer as SNI, number 01-3920-1995, the corn was well stored at moisture content 14% or below (wet basis. However, conventional corn drying dealed with in-efficient energy process and corn quality degradation. This research evaluated the performance of corn drying assisted by zeolite as moisture adsorbent. In this process, the zeolite and corn were placed in the dryer fluidized by warm air as drying medium under 40 - 50oC. The air evaporated water product from corn, and at same time the zeolite adsorbed moisture in air. So, the relative humidity of air in dryer can be kept low in which enhanced the driving force for drying. Beside that, the moisture adsoprtion by zeolite was exothermic process that can supply the energy for drying or keep the dryer temperature. Thus, the drying rate can be faster. This work foccussed to observe the effect of drying temperature, air velocity, and corn to zeolite ratio on drying time as well as corn quality. As indicators, the drying rate was estimated and the proxymates content such as protein, fat, and carbohydrate content were analyzed. The results showed that compared with conventional fluidised bed dryer, corn drying with zeolite, can speed up drying time as well as improving the constant of drying rate. In addition, the corn proximate nutrition content can be well retained. At operating temperature 40oC, air velocity 9 m.s-1, and zeolite to corn ratio 1:2, the drying time can be 60 minutes shorter compared to that without zeolite.

  1. Morphological characteristics of overdeepenings in high-mountain glacier beds

    Science.gov (United States)

    Haeberli, Wilfried; Cochachin, Alejo; Fischer, Urs; Giráldez, Claudia; Linsbauer, Andreas; Salazar, Cesar

    2014-05-01

    Overdeepenings, i.e. closed topographic depressions with adverse slopes in the flow direction, are characteristic for glacier beds and glacially sculpted landscapes. Besides their importance as geomorphological landforms, groundwater bodies and sedimentary archives, they are of increasing interest in relation to climate-induced lake formation in de-glaciating landscapes and to depth erosion under ice age conditions in connection with the long-term safety of radioactive waste repositories in some mid-latitude countries. Quantitative predictions of their shape, distribution and conditions of occurrence, however, remain difficult. One major problem thereby relates to the still unsatisfactory treatment in glacier erosion theory of sediment evacuation at glacier beds, especially by subglacial meltwater. An alternative way of searching for realistic/empirical quantitative estimates is, therefore, to analyse the geometry of well-documented overdeepenings. The present study attempts to do this by combining statistical analyses of (a) detailed bathymetries from recently exposed lakes in the Peruvian Andes, (b) numerous bed overdeepenigs below still existing glaciers of the Swiss Alps and the Himalaya-Karakoram region modelled with a robust shear stress approximation linking surface slope to ice thickness at high resolution, and (c, for comparison) reconstructed overdeepenings produced by ice age glaciers in the Swiss Plateau based on numerous drillings and geophysical soundings. The sample of (a) has the advantage that geometries are exactly measured and only subject to young/small sedimentation effects. Sample (b) allows for a comparison with a modern model calculation and with known glacier characteristics. Sample (c) may provide some insights into the question how safely results from high mountain topography can be transferred to sites with markedly different topographic, climatic and glaciological controls (cold-arid lowland). Where possible, mean and maximum values of

  2. Fluidized bed system for calcination of high level radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Pande, D P; Prasad, T L; Yadgiri, N K; Theyyunni, T K [Process Engineering and Systems Development Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    During the operation of nuclear facilities significant quantities of radiochemical liquid effluents of different concentrations and varying chemical compositions are generated. These effluents contain activated radionuclides, corrosion products and fission products. The advantage of feeding the waste in solid form into the vitrifying equipment are multifold. Efforts are therefore made in many countries to calcine the high level waste, and obtain waste in the oxide form before the same is mixed with glass forming additives and fed into the melter unit. An experimental rig for fluidized bed calcination is constructed for carrying out the detailed investigation of this process, in order to adopt the same for plant scale application. To achieve better gas-solid contact and avoid raining down of solids, a distributor of bubble cap type was designed. A review of existing experience at various laboratories and design of new experimental facility for development of calciners are given. (author). 11 refs., 5 figs.

  3. RESEARCH ON THE INFLUENCE OF TEMPERATURE ON THE ACTIVATION OF SELECTED POROUS MNO2 BEDS

    Directory of Open Access Journals (Sweden)

    Iwona Skoczko

    2016-09-01

    Full Text Available Rising demands concerning water treatment and conservation make it necessary to search for more effective as well as cheap and ecologically safe solutions. During the filtration process quartz sand is replaced by filter materials which also have a strong effect on account of reactions taking place on a bed’s surface. Today’s technologies for groundwater and seepage water treatment in rapid filters make use of oxidation beds. They are able to effectively remove manganese (II and iron (II compounds based on heterogeneous oxidation catalysis. The main catalyst of the manganese removal process in terms of its catalytic oxidation in filtration beds is manganese dioxide. This compound is used as an oxidizing agent in many processes. The research conducted as part of this paper was aimed at creating a product with the qualities similar to a popular Greensand bed protected by patent. The authors tested washed quartz sand varying in granulation which was subject to activation in 10% KMnO4 solution. Grains of quartz sand after covering them with a permanent coat of manganese oxide developed the superficial oxidation layer. While performing the tests, a temperature of the process served as a variable. The beds produced as a result of the experiment enable the removal of iron and manganese from water without prior alkylation. Furthermore, they are an effective method of purifying water of organic pollutants and ammoniacal nitrogen. They function as oxidizing and filtering masses.

  4. Advances in high temperature chemistry

    CERN Document Server

    Eyring, Leroy

    1969-01-01

    Advances in High Temperature Chemistry, Volume 2 covers the advances in the knowledge of the high temperature behavior of materials and the complex and unfamiliar characteristics of matter at high temperature. The book discusses the dissociation energies and free energy functions of gaseous monoxides; the matrix-isolation technique applied to high temperature molecules; and the main features, the techniques for the production, detection, and diagnosis, and the applications of molecular beams in high temperatures. The text also describes the chemical research in streaming thermal plasmas, as w

  5. FY 1975 Report on results of Sunshine Project. Development of techniques of digging high-temperature beds (Researches on roller cutter bits); 1975 nendo koon chiso kussaku gijutsu no kaihatsu. Roller cutter bit no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1976-03-31

    It is necessary to establish the techniques for digging bedrocks under elevated temperature and pressure for development and utilization of geothermal energy. This project is aimed at development of heat- and wear-resistant bit cutters, which have efficient tooth edge forms and arrangements. Another factor that determines bit serviceability is the bearing built in a cutter, and this project is also aimed at development of long-serviceable bit bearings by improving their resistance to heat. Four types of bits were developed, on a trial basis, and tested (size: 8.625 inches, two types of tooth forms, different shapes and arrangements of insert tips). They were tested for, e.g., their excavation rate, under the conditions of 5 tons as load and 100 rpm. It is found that their excavation rate vary with load, speed of rotation, tooth height and tooth form. Excavation torque increases in almost proportion to load. The sliding bearings of silver and its alloy were tested, to confirm the effects of silver. It is necessary to conduct the field tests in an actual geothermal area of high rock temperature and the ground tests with test machines to dig heated rocks in and after FY 1975, for overall evaluation of the bits developed. (NEDO)

  6. Lay-out and construction of a pressure vessel built-up of cast steel segments for a pebble-bed high temperature reactor with a thermal power of 3000 MW

    International Nuclear Information System (INIS)

    Voigt, J.

    1978-03-01

    The prestressed cast vessel is an alternative to the prestressed concrete vessel for big high temperature reactors. In this report different cast steel vessel concepts for an HTR for generation of current with 3000 MW(th) are compared concerning their realization and economy. The most favourable variant serves as a base for the lay-out of the single vessel components as cast steel segments, bracing, cooling and outer sealing. Hereby the actual available possibilities of production and transport are considered. For the concept worked out possibilities of inspection and repair are suggested. A comparison of costs with adequate proposititons of the industry for a prestressed concrete and a cast iron pressure vessel investigates the economical competition. (orig.) [de

  7. Two stage, low temperature, catalyzed fluidized bed incineration with in situ neutralization for radioactive mixed wastes

    International Nuclear Information System (INIS)

    Wade, J.F.; Williams, P.M.

    1995-01-01

    A two stage, low temperature, catalyzed fluidized bed incineration process is proving successful at incinerating hazardous wastes containing nuclear material. The process operates at 550 degrees C and 650 degrees C in its two stages. Acid gas neutralization takes place in situ using sodium carbonate as a sorbent in the first stage bed. The feed material to the incinerator is hazardous waste-as defined by the Resource Conservation and Recovery Act-mixed with radioactive materials. The radioactive materials are plutonium, uranium, and americium that are byproducts of nuclear weapons production. Despite its low temperature operation, this system successfully destroyed poly-chlorinated biphenyls at a 99.99992% destruction and removal efficiency. Radionuclides and volatile heavy metals leave the fluidized beds and enter the air pollution control system in minimal amounts. Recently collected modeling and experimental data show the process minimizes dioxin and furan production. The report also discusses air pollution, ash solidification, and other data collected from pilot- and demonstration-scale testing. The testing took place at Rocky Flats Environmental Technology Site, a US Department of Energy facility, in the 1970s, 1980s, and 1990s

  8. High-Temperature Piezoelectric Sensing

    Directory of Open Access Journals (Sweden)

    Xiaoning Jiang

    2013-12-01

    Full Text Available Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented.

  9. High temperature superconductor accelerator magnets

    NARCIS (Netherlands)

    van Nugteren, J.

    2016-01-01

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding 20T. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and

  10. Endurance and failure of an alumina-based monopropellant microthruster with integrated heater, catalytic bed and temperature sensors

    Science.gov (United States)

    Khaji, Zahra; Klintberg, Lena; Barbade, Dhananjay; Palmer, Kristoffer; Thornell, Greger

    2017-05-01

    Monopropellant ceramic microthrusters with an integrated heater, catalytic bed and two temperature sensors, but of various designs, were manufactured by milling a fluidic channel and chamber, and a nozzle, and screen printing platinum patterns on green tapes of alumina that were stacked and laminated before sintering. In order to increase the surface area of the catalytic bed, the platinum paste was mixed with a sacrificial paste that disappeared during sintering, to leave behind a porous and rough layer. As an early development level in manufacturing robust and high-temperature tolerant microthrusters, the influence of design on the temperature gradients and dry temperature tolerance of the devices was studied. On average, the small reaction chambers showed a more than 1.5 times higher dry temperature tolerance (in centigrade) compared to devices with larger chambers, independent of the heater and device size. However, for a given temperature, big devices consumed on average 2.9 times more power than the small ones. It was also found that over the same area and under the same heating conditions, devices with small chambers were subjected to approximately 40% smaller temperature differences. A pressure test done on two small devices with small chambers revealed that pressures of at least 26.3 bar could be tolerated. Above this pressure, the interfaces failed but the devices were not damaged. To investigate the cooling effect of the micropropellant, the endurance of a full thruster was also studied under wet testing where it was fed with 31 wt.% hydrogen peroxide. The thruster demonstrated complete evaporation and/or full decomposition at a power above 3.7 W for a propellant flow of 50 µl min-1. At this power, the catalytic bed locally reached a temperature of 147 °C. The component was successfully heated to an operating temperature of 307 °C, where it cracked. Under these firing conditions, and assuming complete decomposition, calculations give a thrust and

  11. Influence of various chlorine additives on the partitioning of heavy metals during low-temperature two-stage fluidized bed incineration.

    Science.gov (United States)

    Peng, Tzu-Huan; Lin, Chiou-Liang

    2014-12-15

    In this study, a pilot-scale low-temperature two-stage fluidized bed incinerator was evaluated for the control of heavy metal emissions using various chlorine (Cl) additives. Artificial waste containing heavy metals was selected to simulate municipal solid waste (MSW). Operating parameters considered included the first-stage combustion temperature, gas velocity, and different kinds of Cl additives. Results showed that the low-temperature two-stage fluidized bed reactor can be an effective system for the treatment of MSW because of its low NO(x), CO, HCl, and heavy metal emissions. The NO(x) and HCl emissions could be decreased by 42% and 70%, respectively. Further, the results showed that heavy metal emissions were reduced by bed material adsorption and filtration in the second stage. Regarding the Cl addition, although the Cl addition would reduce the metal capture in the first-stage sand bed, but those emitted metals could be effectively captured by the filtration of second stage. No matter choose what kind of additive, metal emissions in the low-temperature two-stage system are still lower than in a traditional high-temperature one-stage system. The results also showed that metal emissions depend not only on the combustion temperature but also on the physicochemical properties of the different metal species. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Bed mixing dryer for high moisture content fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hulkkonen, S; Heinonen, O. [Imatran Voima Oy, Vantaa (Finland)

    1998-12-31

    Bed mixing dryer is a new type of fuel drying technology for fluidized bed combustion. The idea is to extract hot bed material from the fluidized bed and use it as a heat source for drying the fuel. Drying occurs at steam atmosphere which makes it possible to recover the latent heat of evaporation to process. This improves the thermal efficiency of the power plant process considerably, especially in combined heat and power applications. Imatran Voima Oy (IVO) has developed the Bed Mixing Dryer technology since early 1990s. The first pilot plant was built in 1994 to IVO`s Kuusamo peat and wood fired power plant. The capacity of the plant is 6 MW{sub e} and 20 MW of district heat. In Kuusamo the dryer is connected to a bubbling fluidized bed. Since it`s commissioning the dryer has been used successfully for about 3000 hours during the heating season in wintertime. The second application of the technology will be a demonstration project in Oerebro (S). IVO Power Engineering Ltd will supply in 1997 a dryer to Oerebro Energi`s peat, wood and coal fired CHP plant equipped with circulating fluidized bed boiler. The fuel to be dried is sawdust with fuel input of about 60 MW. In Kuusamo the dryer produces 3 MW of additional district heat and in Oerebro 6 MW. The fuels in Kuusamo are peat, saw dust and bark. In addition to the municipal heat production this type of drying technology has its benefits in pulp and paper industry processes. Disposal of paper mill sludges is becoming more difficult and costly which has resulted in need of alternative treatment. Drying of the sludge before combustion in a boiler for power production is an attractive option. At the moment IVO is carrying out several studies to apply the Bed Mixing Dryer in pulp and paper industry processes. Economy of drying the sludge looks promising

  13. Bed mixing dryer for high moisture content fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hulkkonen, S.; Heinonen, O. [Imatran Voima Oy, Vantaa (Finland)

    1997-12-31

    Bed mixing dryer is a new type of fuel drying technology for fluidized bed combustion. The idea is to extract hot bed material from the fluidized bed and use it as a heat source for drying the fuel. Drying occurs at steam atmosphere which makes it possible to recover the latent heat of evaporation to process. This improves the thermal efficiency of the power plant process considerably, especially in combined heat and power applications. Imatran Voima Oy (IVO) has developed the Bed Mixing Dryer technology since early 1990s. The first pilot plant was built in 1994 to IVO`s Kuusamo peat and wood fired power plant. The capacity of the plant is 6 MW{sub e} and 20 MW of district heat. In Kuusamo the dryer is connected to a bubbling fluidized bed. Since it`s commissioning the dryer has been used successfully for about 3000 hours during the heating season in wintertime. The second application of the technology will be a demonstration project in Oerebro (S). IVO Power Engineering Ltd will supply in 1997 a dryer to Oerebro Energi`s peat, wood and coal fired CHP plant equipped with circulating fluidized bed boiler. The fuel to be dried is sawdust with fuel input of about 60 MW. In Kuusamo the dryer produces 3 MW of additional district heat and in Oerebro 6 MW. The fuels in Kuusamo are peat, saw dust and bark. In addition to the municipal heat production this type of drying technology has its benefits in pulp and paper industry processes. Disposal of paper mill sludges is becoming more difficult and costly which has resulted in need of alternative treatment. Drying of the sludge before combustion in a boiler for power production is an attractive option. At the moment IVO is carrying out several studies to apply the Bed Mixing Dryer in pulp and paper industry processes. Economy of drying the sludge looks promising

  14. High temperature materials; Materiaux a hautes temperatures

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    The aim of this workshop is to share the needs of high temperature and nuclear fuel materials for future nuclear systems, to take stock of the status of researches in this domain and to propose some cooperation works between the different research organisations. The future nuclear systems are the very high temperature (850 to 1200 deg. C) gas cooled reactors (GCR) and the molten salt reactors (MSR). These systems include not only the reactor but also the fabrication and reprocessing of the spent fuel. This document brings together the transparencies of 13 communications among the 25 given at the workshop: 1) characteristics and needs of future systems: specifications, materials and fuel needs for fast spectrum GCR and very high temperature GCR; 2) high temperature materials out of neutron flux: thermal barriers: materials, resistance, lifetimes; nickel-base metal alloys: status of knowledge, mechanical behaviour, possible applications; corrosion linked with the gas coolant: knowledge and problems to be solved; super-alloys for turbines: alloys for blades and discs; corrosion linked with MSR: knowledge and problems to be solved; 3) materials for reactor core structure: nuclear graphite and carbon; fuel assembly structure materials of the GCR with fast neutron spectrum: status of knowledge and ceramics and cermets needs; silicon carbide as fuel confinement material, study of irradiation induced defects; migration of fission products, I and Cs in SiC; 4) materials for hydrogen production: status of the knowledge and needs for the thermochemical cycle; 5) technologies: GCR components and the associated material needs: compact exchangers, pumps, turbines; MSR components: valves, exchangers, pumps. (J.S.)

  15. A nonintrusive temperature measuring system for estimating deep body temperature in bed.

    Science.gov (United States)

    Sim, S Y; Lee, W K; Baek, H J; Park, K S

    2012-01-01

    Deep body temperature is an important indicator that reflects human being's overall physiological states. Existing deep body temperature monitoring systems are too invasive to apply to awake patients for a long time. Therefore, we proposed a nonintrusive deep body temperature measuring system. To estimate deep body temperature nonintrusively, a dual-heat-flux probe and double-sensor probes were embedded in a neck pillow. When a patient uses the neck pillow to rest, the deep body temperature can be assessed using one of the thermometer probes embedded in the neck pillow. We could estimate deep body temperature in 3 different sleep positions. Also, to reduce the initial response time of dual-heat-flux thermometer which measures body temperature in supine position, we employed the curve-fitting method to one subject. And thereby, we could obtain the deep body temperature in a minute. This result shows the possibility that the system can be used as practical temperature monitoring system with appropriate curve-fitting model. In the next study, we would try to establish a general fitting model that can be applied to all of the subjects. In addition, we are planning to extract meaningful health information such as sleep structure analysis from deep body temperature data which are acquired from this system.

  16. High Temperature Superconductor Resonator Detectors

    Data.gov (United States)

    National Aeronautics and Space Administration — High Temperature Superconductor (HTS) infrared detectors were studied for years but never matured sufficiently for infusion into instruments. Several recent...

  17. High Temperature Superconductor Machine Prototype

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Træholt, Chresten

    2011-01-01

    A versatile testing platform for a High Temperature Superconductor (HTS) machine has been constructed. The stationary HTS field winding can carry up to 10 coils and it is operated at a temperature of 77K. The rotating armature is at room temperature. Test results and performance for the HTS field...

  18. Low-temperature gasification of waste tire in a fluidized bed

    International Nuclear Information System (INIS)

    Xiao Gang; Ni Mingjiang; Chi Yong; Cen Kefa

    2008-01-01

    In order to recovery energy and materials from waste tire efficiently, low-temperature gasification is proposed. Experiments are carried out in a lab-scale fluidized bed at 400-800 deg. C when equivalence ratio (ER) is 0.2-0.6. Low heat value (LHV) of syngas increases with increasing temperature or decreasing ER, and the yield is in proportion to ER linearly. The yield of carbon black decreases with increasing temperature or ER lightly. When temperature is over 600 deg. C, characteristics of carbon black is similar. When temperature is over 700 deg. C, LHV of syngas rises up lightly with increasing temperature, which indicates that it hardly facilitates gasification any more. It is suitable for tire gasification when temperature is 650-700 deg. C and ER is 0.2-0.4. Under this condition, LHV and yield of syngas are about 4000-9000 kJ/Nm 3 and 1.8-3.7 Nm 3 /kg, respectively; surface area and yield of carbon black lie in range of 20-30 m 3 /g and 550-650 g/kg, respectively. The carbon balance of these experiments achieves 85-95% when temperature is over 600 deg. C

  19. High Temperature Fluoride Salt Test Loop

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, Adam M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cunningham, Richard Burns [Univ. of Tennessee, Knoxville, TN (United States); Fugate, David L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holcomb, David Eugene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kisner, Roger A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peretz, Fred J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wilson, Dane F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yoder, Jr, Graydon L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    Effective high-temperature thermal energy exchange and delivery at temperatures over 600°C has the potential of significant impact by reducing both the capital and operating cost of energy conversion and transport systems. It is one of the key technologies necessary for efficient hydrogen production and could potentially enhance efficiencies of high-temperature solar systems. Today, there are no standard commercially available high-performance heat transfer fluids above 600°C. High pressures associated with water and gaseous coolants (such as helium) at elevated temperatures impose limiting design conditions for the materials in most energy systems. Liquid salts offer high-temperature capabilities at low vapor pressures, good heat transport properties, and reasonable costs and are therefore leading candidate fluids for next-generation energy production. Liquid-fluoride-salt-cooled, graphite-moderated reactors, referred to as Fluoride Salt Reactors (FHRs), are specifically designed to exploit the excellent heat transfer properties of liquid fluoride salts while maximizing their thermal efficiency and minimizing cost. The FHR s outstanding heat transfer properties, combined with its fully passive safety, make this reactor the most technologically desirable nuclear power reactor class for next-generation energy production. Multiple FHR designs are presently being considered. These range from the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) [1] design originally developed by UC-Berkeley to the Small Advanced High-Temperature Reactor (SmAHTR) and the large scale FHR both being developed at ORNL [2]. The value of high-temperature, molten-salt-cooled reactors is also recognized internationally, and Czechoslovakia, France, India, and China all have salt-cooled reactor development under way. The liquid salt experiment presently being developed uses the PB-AHTR as its focus. One core design of the PB-AHTR features multiple 20 cm diameter, 3.2 m long fuel channels

  20. HTR-2002: Proceedings of the conference on high temperature reactors

    International Nuclear Information System (INIS)

    2002-01-01

    High temperature reactors are considered as future inherently safe and efficient energy sources. The presentations covered all the relevant aspects of the existing HTGRs and/or helium cooled pebble bed reactors. They were sorted into 7 sessions: HTR Projects and Programmes; Fuel and Fuel Cycle; Physics and Neutronics; Thermohydraulic Calculation; Engineering, Design and Applications; Materials and Components; Safety and Licensing

  1. Modeling of river bed deformation composed of frozen sediments with increasing environmental temperature

    Directory of Open Access Journals (Sweden)

    E. I. Debolskaya

    2013-01-01

    Full Text Available This paper is devoted to investigation of the influence of river flow and of the temperature rise on the deformation of the coastal slopes composed of permafrost with the inclusion of ice layer. The method of investigation is the laboratory and mathematical modeling. The laboratory experiments have shown that an increase in water and air temperature changes in a laboratory analogue of permafrost causes deformation of the channel even without wave action, i.e. at steady-state flow and non-erosive water flow velocity. The previously developed model of the bed deformation was improved to account for long-term changes of soil structure with increasing temperature. The three-dimensional mathematical model of coastal slopes thermoerosion of the rivers flowing in permafrost regions, and its verification was based on the results of laboratory experiments conducted in the hydraulic tray. Analysis of the results of mathematical and laboratory modeling showed that bed deformation of the rivers flowing in the permafrost zone, significantly different from the deformation of channels composed of soils not susceptible to the influence of the phase transition «water-ice», and can occur even under the non-erosive velocity of the water flow.

  2. FY 1975 Report on results of Sunshine Project. Development of techniques of digging high-temperature beds (Development of solid bits and air-friction bearings); 1975 nendo koon chiso kussaku gijutsu no kaihatsu. Solid bit oyobi air friction bearing no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1976-03-31

    A combination of superhard alloy and diamond powder has been widely used as the solid type edge. The solid type with only a superhard alloy edge is no better than the traditional metal bit. It is ironical to admit that one of the most important items in the development of solid bits for digging high-temperature beds is not related to high temperature itself but development of highly efficient, long serviceable bits, growing out of the inefficient digging mechanisms for the conventional solid bits. It is considered that use of a superhard alloy edge is disadvantageous for digging hard rocks in the so-called scratching manner, for the two major reasons: (1) a superhard alloy is certainly resistant to wear, but nothing to that of diamond, and (2) it is homogeneous and lacks directional properties, such as the cleavage plane of diamond, which is effective for cutting. This project is aimed at development, on a trial basis, and eventual commercialization of new types of solid bits serviceable for extended periods by drastically improving suerhard alloys to provide them with new structures, e.g., those corresponding to the crystal axes of diamond, and also introducing a concept of crushing. (NEDO)

  3. The influence of temperature on limestone sulfation and attrition under fluidized bed combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Montagnaro, Fabio [Dipartimento di Chimica - Universita degli Studi di Napoli Federico II, Complesso Universitario del Monte di Sant' Angelo, 80126 Napoli (Italy); Salatino, Piero [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Scala, Fabrizio [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy)

    2010-04-15

    The influence of temperature on attrition of two limestones during desulfurization in a fluidized bed reactor was investigated. Differences in the microstructure of the two limestones were reflected by a different thickness of the sulfate shell formed upon sulfation and by a different value of the ultimate calcium conversion degree. Particle attrition and fragmentation were fairly small under moderately bubbling fluidization conditions for both limestones. An increase of temperature from 850 C to 900 C led to an increase of the attrition rate, most likely because of a particle weakening effect caused by a faster CO{sub 2} evolution during calcination. This weakening effect, however, was not sufficiently strong to enhance particle fragmentation in the bed. The progress of sulfation, associated to the build-up of a hard sulfate shell around the particles, led in any case to a decrease of the extent of attrition. Sulfation at 900 C was less effective than at 850 C, and this was shown to be related to the porosimetric features of the different samples. (author)

  4. Water and sediment temperatures at mussel beds in the upper Mississippi River basin

    Science.gov (United States)

    Newton, Teresa J.; Sauer, Jennifer; Karns, Byron

    2013-01-01

    Native freshwater mussels are in global decline and urgently need protection and conservation. Declines in the abundance and diversity of North American mussels have been attributed to human activities that cause pollution, waterquality degradation, and habitat destruction. Recent studies suggest that effects of climate change may also endanger native mussel assemblages, as many mussel species are living close to their upper thermal tolerances. Adult and juvenile mussels spend a large fraction of their lives burrowed into sediments of rivers and lakes. Our objective was to measure surface water and sediment temperatures at known mussel beds in the Upper Mississippi (UMR) and St. Croix (SCR) rivers to estimate the potential for sediments to serve as thermal refugia. Across four mussel beds in the UMR and SCR, surface waters were generally warmer than sediments in summer, and were cooler than sediments in winter. This suggests that sediments may act as a thermal buffer for mussels in these large rivers. Although the magnitude of this effect was usually cause mortality in laboratory studies. These data suggest that elevated water temperatures resulting from global warming, thermal discharges, water extraction, and/or droughts have the potential to adversely affect native mussel assemblages.

  5. On equivalent roughness of mobile bed at high shear stress

    Czech Academy of Sciences Publication Activity Database

    Matoušek, Václav; Krupička, Jan

    2009-01-01

    Roč. 57, č. 3 (2009), s. 191-199 ISSN 0042-790X R&D Projects: GA ČR GA103/06/0428 Institutional research plan: CEZ:AV0Z20600510 Keywords : bed shear * experiment * hydraulic transport * sediment transport Subject RIV: BK - Fluid Dynamics Impact factor: 1.000, year: 2009

  6. Advanced High Temperature Structural Seals

    Science.gov (United States)

    Newquist, Charles W.; Verzemnieks, Juris; Keller, Peter C.; Rorabaugh, Michael; Shorey, Mark

    2002-10-01

    This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 pound payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs.

  7. Effect of Different Operating Temperatures on the Biological Hydrogen Methanation in Trickle Bed Reactors

    Directory of Open Access Journals (Sweden)

    Andreas Lemmer

    2018-05-01

    Full Text Available To improve the reactor efficiency, this study investigated the influence of temperature on the biological hydrogen methanation (BHM in trickle-bed reactors (TBR. Rising temperatures increase the metabolic activity of methanogenic microorganisms, thus leading to higher reactor specific methane formation rates (MFR. In order to quantify the potential for improved performance, experiments with four different operating temperatures ranging from 40 to 55 °C were carried out. Methane content increased from 88.29 ± 2.12 vol % at 40 °C to 94.99 ± 0.81 vol % at 55 °C with a stable biological process. Furthermore, a reactor specific methane formation rate (MFR of up to 8.85 ± 0.45 m3 m−3 d−1 was achieved. It could be shown that the microorganisms were able to adapt to higher temperatures within hours. The tests showed that TBR performance with regard to BHM can be significantly increased by increasing the operating temperature.

  8. HIGH TEMPERATURE POLYMER FUEL CELLS

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Qingfeng, Li; He, Ronghuan

    2003-01-01

    This paper will report recent results from our group on polymer fuel cells (PEMFC) based on the temperature resistant polymer polybenzimidazole (PBI), which allow working temperatures up to 200°C. The membrane has a water drag number near zero and need no water management at all. The high working...

  9. High Temperature Materials Laboratory (HTML)

    Data.gov (United States)

    Federal Laboratory Consortium — The six user centers in the High Temperature Materials Laboratory (HTML), a DOE User Facility, are dedicated to solving materials problems that limit the efficiency...

  10. Barriers to high conversion operations in an ebullated bed unit -- Relationship between sedimentation and operability

    Energy Technology Data Exchange (ETDEWEB)

    Sherwood, D. [Criterion Catalysts Company L.P., Houston, TX (United States)

    2000-07-01

    Ebullated-Bed (EB) catalytic processes are high temperature, high pressure residue hydrocrackers, which transform sour feeds into light, sweet products. EB processes typically involve one or more trains, with one, two, or three EB reactors in series. The key to operating any EB process is to control the 'sediment' which tends to increase with increasing level of conversion. Sediment problems are generally attributed to the catalyst. While this is true in some cases, there are certain problems that occur regardless of the catalyst used, whereas in some situations sediments from the EB process can actually be controlled by the catalyst. This paper describes two typical sedimentation patterns; one in which the sediment increases, and another in which sediment decreases as the EB products move through the recovery section. The benefits of sediment control are illustrated for the latter sedimentation pattern.

  11. High temperature divertor plasma operation

    International Nuclear Information System (INIS)

    Ohyabu, Nobuyoshi.

    1991-02-01

    High temperature divertor plasma operation has been proposed, which is expected to enhance the core energy confinement and eliminates the heat removal problem. In this approach, the heat flux is guided through divertor channel to a remote area with a large target surface, resulting in low heat load on the target plate. This allows pumping of the particles escaping from the core and hence maintaining of the high divertor temperature, which is comparable to the core temperature. The energy confinement is then determined by the diffusion coefficient of the core plasma, which has been observed to be much lower than the thermal diffusivity. (author)

  12. High temperature high vacuum creep testing facilities

    International Nuclear Information System (INIS)

    Matta, M.K.

    1985-01-01

    Creep is the term used to describe time-dependent plastic flow of metals under conditions of constant load or stress at constant high temperature. Creep has an important considerations for materials operating under stresses at high temperatures for long time such as cladding materials, pressure vessels, steam turbines, boilers,...etc. These two creep machines measures the creep of materials and alloys at high temperature under high vacuum at constant stress. By the two chart recorders attached to the system one could register time and temperature versus strain during the test . This report consists of three chapters, chapter I is the introduction, chapter II is the technical description of the creep machines while chapter III discuss some experimental data on the creep behaviour. Of helium implanted stainless steel. 13 fig., 3 tab

  13. High temperature corrosion of metals

    International Nuclear Information System (INIS)

    Quadakkers, W.J.; Schuster, H.; Ennis, P.J.

    1988-08-01

    This paper covers three main topics: 1. high temperature oxidation of metals and alloys, 2. corrosion in sulfur containing environments and 3. structural changes caused by corrosion. The following 21 subjects are discussed: Influence of implanted yttrium and lanthanum on the oxidation behaviour of beta-NiA1; influence of reactive elements on the adherence and protective properties of alumina scales; problems related to the application of very fine markers in studying the mechanism of thin scale formation; oxidation behaviour of chromia forming Co-Cr-Al alloys with or without reactive element additions; growth and properties of chromia-scales on high-temperature alloys; quantification of the depletion zone in high temperature alloys after oxidation in process gas; effects of HC1 and of N2 in the oxidation of Fe-20Cr; investigation under nuclear safety aspects of Zircaloy-4 oxidation kinetics at high temperatures in air; on the sulfide corrosion of metallic materials; high temperature sulfide corrosion of Mn, Nb and Nb-Si alloys; corrosion behaviour or NiCrAl-based alloys in air and air-SO2 gas mixtures; sulfidation of cobalt at high temperatures; preoxidation for sulfidation protection; fireside corrosion and application of additives in electric utility boilers; transport properties of scales with complex defect structures; observations of whiskers and pyramids during high temperature corrosion of iron in SO2; corrosion and creep of alloy 800H under simulated coal gasification conditions; microstructural changes of HK 40 cast alloy caused by exploitation in tubes in steam reformer installation; microstructural changes during exposure in corrosive environments and their effect on mechanical properties; coatings against carburization; mathematical modeling of carbon diffusion and carbide precipitation in Ni-Cr-based alloys. (MM)

  14. Dehydration/hydration of granular beds for thermal storage applications: a combined NMR and temperature study

    NARCIS (Netherlands)

    Donkers, P.A.J.; Pel, L.; Adan, O.C.G.

    For heat/cold storage systems a granular bed of salt hydrates is studied during dehydration/hydration. The water density in these beds are measured with help of NMR. Diffusion based dehydration of a granular bed of Na2SO4·10H2O is shown to be internally limited as larger grains dehydrate faster than

  15. Fluidized bed combustion of single coal char particles at high CO{sub 2} concentration

    Energy Technology Data Exchange (ETDEWEB)

    Scala, F.; Chirone, R. [CNR, Naples (Italy)

    2010-12-15

    Combustion of single coal char particles was studied at 850{sup o}C in a lab-scale fluidized bed at high CO{sub 2} concentration, typical of oxyfiring conditions. The burning rate of the particles was followed as a function of time by continuously measuring the outlet CO and O{sub 2} concentrations. Some preliminary evaluations on the significance of homogeneous CO oxidation in the reactor and of carbon gasification by CO{sub 2} in the char were also carried out. Results showed that the carbon burning rate increases with oxygen concentration and char particle size. The particle temperature is approximately equal to that of the bed up to an oxygen concentration of 2%, but it is considerably higher for larger oxygen concentrations. Both CO{sub 2} gasification of char and homogeneous CO oxidation are not negligible. The gasification reaction rate is slow and it is likely to be controlled by intrinsic kinetics. During purely gasification conditions the extent of carbon loss due to particle attrition by abrasion (estimated from the carbon mass balance) appears to be much more important than under combustion conditions.

  16. High temperature electronic gain device

    International Nuclear Information System (INIS)

    McCormick, J.B.; Depp, S.W.; Hamilton, D.J.; Kerwin, W.J.

    1979-01-01

    An integrated thermionic device suitable for use in high temperature, high radiation environments is described. Cathode and control electrodes are deposited on a first substrate facing an anode on a second substrate. The substrates are sealed to a refractory wall and evacuated to form an integrated triode vacuum tube

  17. RPC operation at high temperature

    CERN Document Server

    Aielli, G; Cardarelli, R; Di Ciaccio, A; Di Stante, L; Liberti, B; Paoloni, A; Pastori, E; Santonico, R

    2003-01-01

    The resistive electrodes of RPCs utilised in several current experiments (ATLAS, CMS, ALICE, BABAR and ARGO) are made of phenolic /melaminic polymers, with room temperature resistivities ranging from 10**1**0 Omega cm, for high rate operation in avalanche mode, to 5 multiplied by 10**1**1 Omega cm, for streamer mode operation at low rate. The resistivity has however a strong temperature dependence, decreasing exponentially with increasing temperature. We have tested several RPCs with different electrode resistivities in avalanche as well as in streamer mode operation. The behaviours of the operating current and of the counting rate have been studied at different temperatures. Long-term operation has also been studied at T = 45 degree C and 35 degree C, respectively, for high and low resistivity electrodes RPCs.

  18. HIgh Temperature Photocatalysis over Semiconductors

    Science.gov (United States)

    Westrich, Thomas A.

    Due in large part to in prevalence of solar energy, increasing demand of energy production (from all sources), and the uncertain future of petroleum energy feedstocks, solar energy harvesting and other photochemical systems will play a major role in the developing energy market. This dissertation focuses on a novel photochemical reaction process: high temperature photocatalysis (i.e., photocatalysis conducted above ambient temperatures, T ≥ 100°C). The overarching hypothesis of this process is that photo-generated charge carriers are able to constructively participate in thermo-catalytic chemical reactions, thereby increasing catalytic rates at one temperature, or maintaining catalytic rates at lower temperatures. The photocatalytic oxidation of carbon deposits in an operational hydrocarbon reformer is one envisioned application of high temperature photocatalysis. Carbon build-up during hydrocarbon reforming results in catalyst deactivation, in the worst cases, this was shown to happen in a period of minutes with a liquid hydrocarbon. In the presence of steam, oxygen, and above-ambient temperatures, carbonaceous deposits were photocatalytically oxidized over very long periods (t ≥ 24 hours). This initial experiment exemplified the necessity of a fundamental assessment of high temperature photocatalytic activity. Fundamental understanding of the mechanisms that affect photocatalytic activity as a function of temperatures was achieved using an ethylene photocatalytic oxidation probe reaction. Maximum ethylene photocatalytic oxidation rates were observed between 100 °C and 200 °C; the maximum photocatalytic rates were approximately a factor of 2 larger than photocatalytic rates at ambient temperatures. The loss of photocatalytic activity at temperatures above 200 °C is due to a non-radiative multi-phonon recombination mechanism. Further, it was shown that the fundamental rate of recombination (as a function of temperature) can be effectively modeled as a

  19. High temperature thermoelectric energy conversion

    International Nuclear Information System (INIS)

    Wood, C.

    1986-01-01

    Considerable advances were made in the late '50's and early early '60's in the theory and development of materials for high-temperature thermoelectric energy conversion. This early work culminated in a variety of materials, spanning a range of temperatures, with the product of the figure of merit, Z, and temperature, T, i.e., the dimensionless figure of merit, ZT, of the order of one. This experimental limitation appeared to be universal and led a number of investigators to explore the possibility that a ZT - also represents a theoretical limitation. It was found not to be so

  20. Simulation of a high efficiency multi-bed adsorption heat pump

    International Nuclear Information System (INIS)

    TeGrotenhuis, W.E.; Humble, P.H.; Sweeney, J.B.

    2012-01-01

    Attaining high energy efficiency with adsorption heat pumps is challenging due to thermodynamic losses that occur when the sorbent beds are thermally cycled without effective heat recuperation. The multi-bed concept described here enables high efficiency by effectively transferring heat from beds being cooled to beds being heated. A simplified lumped-parameter model and detailed finite element analysis are used to simulate a sorption compressor, which is used to project the overall heat pump coefficient of performance. Results are presented for ammonia refrigerant and a nano-structured monolithic carbon sorbent specifically modified for the application. The effects of bed geometry and number of beds on system performance are explored, and the majority of the performance benefit is obtained with four beds. Results indicate that a COP of 1.24 based on heat input is feasible at AHRI standard test conditions for residential HVAC equipment. When compared on a basis of primary energy input, performance equivalent to SEER 13 or 14 are theoretically attainable with this system. - Highlights: ► A multi-bed concept for adsorption heat pumps is capable of high efficiency. ► Modeling is used to simulate sorption compressor and overall heat pump performance. ► Results are presented for ammonia refrigerant and a nano-structured monolithic carbon sorbent. ► The majority of the efficiency benefit is obtained with four beds. ► Predicted COP as high as 1.24 for cooling is comparable to SEER 13 or 14 for electric heat pumps.

  1. High Temperature Transparent Furnace Development

    Science.gov (United States)

    Bates, Stephen C.

    1997-01-01

    This report describes the use of novel techniques for heat containment that could be used to build a high temperature transparent furnace. The primary objective of the work was to experimentally demonstrate transparent furnace operation at 1200 C. Secondary objectives were to understand furnace operation and furnace component specification to enable the design and construction of a low power prototype furnace for delivery to NASA in a follow-up project. The basic approach of the research was to couple high temperature component design with simple concept demonstration experiments that modify a commercially available transparent furnace rated at lower temperature. A detailed energy balance of the operating transparent furnace was performed, calculating heat losses through the furnace components as a result of conduction, radiation, and convection. The transparent furnace shells and furnace components were redesigned to permit furnace operation at at least 1200 C. Techniques were developed that are expected to lead to significantly improved heat containment compared with current transparent furnaces. The design of a thermal profile in a multizone high temperature transparent furnace design was also addressed. Experiments were performed to verify the energy balance analysis, to demonstrate some of the major furnace improvement techniques developed, and to demonstrate the overall feasibility of a high temperature transparent furnace. The important objective of the research was achieved: to demonstrate the feasibility of operating a transparent furnace at 1200 C.

  2. "Green" High-Temperature Polymers

    Science.gov (United States)

    Meador, Michael A.

    1998-01-01

    PMR-15 is a processable, high-temperature polymer developed at the NASA Lewis Research Center in the 1970's principally for aeropropulsion applications. Use of fiber-reinforced polymer matrix composites in these applications can lead to substantial weight savings, thereby leading to improved fuel economy, increased passenger and payload capacity, and better maneuverability. PMR-15 is used fairly extensively in military and commercial aircraft engines components seeing service temperatures as high as 500 F (260 C), such as the outer bypass duct for the F-404 engine. The current world-wide market for PMR-15 materials (resins, adhesives, and composites) is on the order of $6 to 10 million annually.

  3. High-temperature metallography setup

    International Nuclear Information System (INIS)

    Blumenfeld, M.; Shmarjahu, D.; Elfassy, S.

    1979-06-01

    A high-temperature metallography setup is presented. In this setup the observation of processes such as that of copper recrystallization was made possible, and the structure of metals such as uranium could be revealed. A brief historical review of part of the research works that have been done with the help of high temperature metallographical observation technique since the beginning of this century is included. Detailed description of metallographical specimen preparation technique and theoretical criteria based on the rate of evaporation of materials present on the polished surface of the specimens are given

  4. High temperature corrosion in gasifiers

    Directory of Open Access Journals (Sweden)

    Bakker Wate

    2004-01-01

    Full Text Available Several commercial scale coal gasification combined cycle power plants have been built and successfully operated during the last 5-10 years. Supporting research on materials of construction has been carried out for the last 20 years by EPRI and others. Emphasis was on metallic alloys for heat exchangers and other components in contact with hot corrosive gases at high temperatures. In this paper major high temperature corrosion mechanisms, materials performance in presently operating gasifiers and future research needs will be discussed.

  5. Establishing Bedding Requirements during Transport and Monitoring Skin Temperature during Cold and Mild Seasons after Transport for Finishing Pigs

    Directory of Open Access Journals (Sweden)

    John McGlone

    2014-05-01

    Full Text Available The broad aim of this study was to determine whether bedding level in the transport trailer influenced pig performance and welfare. Specifically, the objective was to define the bedding requirements of pigs during transportation in commercial settings during cold and mild weather. Animals (n = 112,078 pigs on 572 trailers used were raised in commercial finishing sites and transported in trailers to commercial processing plants. Dead on arrival (DOA, non-ambulatory (NA, and total dead and down (D&D data were collected and skin surface temperatures of the pigs were measured by infrared thermography. Data were collected during winter (Experiment 1 and fall/spring (Experiment 2. Total D&D percent showed no interaction between bedding level and outside air temperature in any experiments. Average skin surface temperature during unloading increased with outside air temperature linearly in both experiments (P < 0.01. In conclusion, over-use of bedding may be economically inefficient. Pig skin surface temperature could be a useful measure of pig welfare during or after transport.

  6. Bed agglomeration characteristics of palm shell and corncob combustion in fluidized bed

    International Nuclear Information System (INIS)

    Chaivatamaset, Pawin; Sricharoon, Panchan; Tia, Suvit

    2011-01-01

    Bed particle agglomeration was studied experimentally in an atmospheric laboratory scale fluidized bed combustor using quartz sand as bed material. Palm shell and corncob were tested. The objectives of the study were (i) to describe the contributions of the biomass ash properties and the operating conditions on the bed agglomeration tendency in term of the bed defluidization time (t def ) and the extent of potassium accumulation in the bed (K/Bed) and (ii) to further elucidate the ash inorganic behaviors and the governing bed agglomeration mechanisms. Defluidization caused by the bed agglomeration was experienced in all experiments during combustion of these biomasses, as a consequence of the presence of potassium in biomass. The experimental results indicated that biomass ash characteristics were the significant influence on the bed agglomeration. The increasing bed temperature, bed particle size and static bed height and the decreasing fluidizing air velocity enhanced the bed agglomeration tendency. The SEM/EDS analyses on the agglomerates confirmed that the agglomeration was attributed to the formation of potassium silicate liquid enriched on the surface of quartz sand particles in conjunction with the high surface temperature of the burning biomass char particles. Thermodynamic examination based on the phase diagram analysis confirmed that the molten phase formation was responsible for the agglomeration. In this study, the high molten ash fraction resulting from the high potassium content in biomass promoted the agglomeration and thus defluidization. - Highlights: → Palm shell and corncob of Thailand are tested their bed agglomeration behaviors during fluidized bed combustion. → The increase of bed temperature, bed particle size and static bed height and the decrease of air velocity enhance bed agglomeration. → The formation of ash derived potassium silicate melts enriched on sand surface is the key process. → The collision between char and sand

  7. High temperature creep of vanadium

    International Nuclear Information System (INIS)

    Juhasz, A.; Kovacs, I.

    1978-01-01

    The creep behaviour of polycrystalline vanadium of 99.7% purity has been investigated in the temperature range 790-880 0 C in a high temperature microscope. It was found that the creep properties depend strongly on the history of the sample. To take this fact into account some additional properties such as the dependence of the yield stress and the microhardness on the pre-annealing treatment have also been studied. Samples used in creep measurements were selected on the basis of their microhardness. The activation energy of creep depends on the microhardness and on the creep temperature. In samples annealed at 1250 0 C for one hour (HV=160 kgf mm -2 ) the rate of creep is controlled by vacancy diffusion in the temperature range 820-880 0 C with an activation energy of 78+-8 kcal mol -1 . (Auth.)

  8. An Experimental Study on Axial Temperature Distribution of Combustion of Dewatered Poultry Sludge in Fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    Abbas A.H.

    2016-01-01

    Full Text Available A laboratory scale bubbling fluidized bed combustor was designed and fabricated to study the combustion of dewatered poultry sludge at different operational parameters. This paper present a study on the influence of equivalent ratio, secondary to primary air ratio and the fuel feed rate on the temperature distribution along the combustor. The equivalent ratio has been changed between 0.8 to 1.4% under poultry sludge feed rate of 10 kg/h and from 0.8 to 1 under poultry sludge feed rate of 15 kg/h. The secondary to primary air ratio was varied from 0.1 to 0.5 at 0.65 m injection height and 1.25 equivalent ratio. The results showed that these factors had a significant influence on the combustion characteristics of poultry sludge. The temperature distribution along the combustor was found to be strongly dependent on the fuel feed rate and the equivalent ratio and it increased when these two factors increased. However, the secondary air ratio increased the temperature in the lower region of the combustor while no significant effect was observed at the upper region of the combustor. The results suggested that the poultry sludge can be used as a fuel with high thermal combustor efficiency.

  9. Three-Dimensional Analysis of the Hot-Spot Fuel Temperature in Pebble Bed and Prismatic Modular Reactors

    International Nuclear Information System (INIS)

    In, W. K.; Lee, S. W.; Lim, H. S.; Lee, W. J.

    2006-01-01

    High temperature gas-cooled reactors(HTGR) have been reviewed as potential sources for future energy needs, particularly for a hydrogen production. Among the HTGRs, the pebble bed reactor(PBR) and a prismatic modular reactor(PMR) are considered as the nuclear heat source in Korea's nuclear hydrogen development and demonstration project. PBR uses coated fuel particles embedded in spherical graphite fuel pebbles. The fuel pebbles flow down through the core during an operation. PMR uses graphite fuel blocks which contain cylindrical fuel compacts consisting of the fuel particles. The fuel blocks also contain coolant passages and locations for absorber and control material. The maximum fuel temperature in the core hot spot is one of the important design parameters for both a PBR and a PMR. The objective of this study is to predict the hot-spot fuel temperature distributions in a PBR and a PMR at a steady state. The computational fluid dynamics(CFD) code, CFX-10 is used to perform the three-dimensional analysis. The latest design data was used here based on the reference reactor designs, PBMR400 and GTMHR60

  10. High-temperature plasma physics

    International Nuclear Information System (INIS)

    Furth, H.P.

    1988-03-01

    Both magnetic and inertial confinement research are entering the plasma parameter range of fusion reactor interest. This paper reviews the individual and common technical problems of these two approaches to the generation of thermonuclear plasmas, and describes some related applications of high-temperature plasma physics

  11. High-Temperature Vibration Damper

    Science.gov (United States)

    Clarke, Alan; Litwin, Joel; Krauss, Harold

    1987-01-01

    Device for damping vibrations functions at temperatures up to 400 degrees F. Dampens vibrational torque loads as high as 1,000 lb-in. but compact enough to be part of helicopter rotor hub. Rotary damper absorbs energy from vibrating rod, dissipating it in turbulent motion of viscous hydraulic fluid forced by moving vanes through small orifices.

  12. Containment of high temperature plasmas

    International Nuclear Information System (INIS)

    Bass, R.W.; Ferguson, H.R.P.; Fletcher, H. Jr.; Gardner, J.; Harrison, B.K.; Larsen, K.M.

    1973-01-01

    Apparatus is described for confining a high temperature plasma which comprises: 1) envelope means shaped to form a toroidal hollow chamber containing a plasma, 2) magnetic field line generating means for confining the plasma in a smooth toroidal shape without cusps. (R.L.)

  13. Chemistry of high temperature superconductors

    CERN Document Server

    1991-01-01

    This review volume contains the most up-to-date articles on the chemical aspects of high temperature oxide superconductors. These articles are written by some of the leading scientists in the field and includes a comprehensive list of references. This is an essential volume for researchers working in the fields of ceramics, materials science and chemistry.

  14. Properties of high temperature SQUIDS

    International Nuclear Information System (INIS)

    Falco, C.M.; Wu, C.T.

    1978-01-01

    A review is given of the present status of weak links and dc and rf biased SQUIDs made with high temperature superconductors. A method for producing reliable, reproducible devices using Nb 3 Sn is outlined, and comments are made on directions future work should take

  15. High temperature component life assessment

    CERN Document Server

    Webster, G A

    1994-01-01

    The aim of this book is to investigate and explain the rapid advances in the characterization of high temperature crack growth behaviour which have been made in recent years, with reference to industrial applications. Complicated mathematics has been minimized with the emphasis placed instead on finding solutions using simplified procedures without the need for complex numerical analysis.

  16. Modelling of Effects of Operating Conditions and Coal Reactivity on Temperature of Burning Particles in Fluidized Bed Combustion

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Karel; Hartman, Miloslav; Pohořelý, Michael; Trnka, Otakar

    2004-01-01

    Roč. 1, č. 2 (2004), s. 261-274 ISSN 1211-1910 R&D Projects: GA AV ČR IAA4072201; GA AV ČR IAA4072001 Institutional research plan: CEZ:AV0Z4072921 Keywords : fluidized bed combustion * char temperature * modelling Subject RIV: DI - Air Pollution ; Quality

  17. High Temperature, High Power Piezoelectric Composite Transducers

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  18. Preliminary neutronic design of high burnup OTTO cycle pebble bed reactor

    International Nuclear Information System (INIS)

    Setiadipura, T.; Zuhair; Irwanto, D.

    2015-01-01

    The pebble bed type High Temperature Gas-cooled Reactor (HTGR) is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR) which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO) cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor design in general, is improving the nuclear fuel utilization which is shown by attaining a higher burnup value. This study performed a preliminary neutronic design study of a 200 MWt OTTO cycle PBR with high burnup while fulfilling the safety criteria of the PBR design.The safety criteria of the design was represented by the per-fuel-pebble maximum power generation of 4.5 kW/pebble. The maximum burnup value was also limited by the tested maximum burnup value which maintained the integrity of the pebble fuel. Parametric surveys were performed to obtain the optimized parameters used in this study, which are the fuel enrichment, per-pebble heavy metal (HM) loading, and the average axial speed of the fuel. An optimum design with burnup value of 131.1 MWd/Kg-HM was achieved in this study which is much higher compare to the burnup of the reference design HTR-MODUL and a previously proposed OTTO-cycle PBR design. This optimum design uses 17% U-235 enrichment with 4 g HM-loading per fuel pebble. (author)

  19. Preliminary Neutronic Design of High Burnup OTTO Cycle Pebble Bed Reactor

    Directory of Open Access Journals (Sweden)

    T. Setiadipura

    2015-04-01

    Full Text Available The pebble bed type High Temperature Gas-cooled Reactor (HTGR is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor design in general, is improving the nuclear fuel utilization which is shown by attaining a higher burnup value. This study performed a preliminary neutronic design study of a 200 MWt OTTO cycle PBR with high burnup while fulfilling the safety criteria of the PBR design.The safety criteria of the design was represented by the per-fuel-pebble maximum power generation of 4.5 kW/pebble. The maximum burnup value was also limited by the tested maximum burnup value which maintained the integrity of the pebble fuel. Parametric surveys were performed to obtain the optimized parameters used in this study, which are the fuel enrichment, per-pebble heavy metal (HM loading, and the average axial speed of the fuel. An optimum design with burnup value of 131.1 MWd/Kg-HM was achieved in this study which is much higher compare to the burnup of the reference design HTR-MODUL and a previously proposed OTTO-cycle PBR design. This optimum design uses 17% U-235 enrichment with 4 g HM-loading per fuel pebble

  20. Summary: High Temperature Downhole Motor

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, David W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-10-01

    Directional drilling can be used to enable multi-lateral completions from a single well pad to improve well productivity and decrease environmental impact. Downhole rotation is typically developed with a motor in the Bottom Hole Assembly (BHA) that develops drilling power (speed and torque) necessary to drive rock reduction mechanisms (i.e., the bit) apart from the rotation developed by the surface rig. Historically, wellbore deviation has been introduced by a “bent-sub,” located in the BHA, that introduces a small angular deviation, typically less than 3 degrees, to allow the bit to drill off-axis with orientation of the BHA controlled at the surface. The development of a high temperature downhole motor would allow reliable use of bent subs for geothermal directional drilling. Sandia National Laboratories is pursuing the development of a high temperature motor that will operate on either drilling fluid (water-based mud) or compressed air to enable drilling high temperature, high strength, fractured rock. The project consists of designing a power section based upon geothermal drilling requirements; modeling and analysis of potential solutions; and design, development and testing of prototype hardware to validate the concept. Drilling costs contribute substantially to geothermal electricity production costs. The present development will result in more reliable access to deep, hot geothermal resources and allow preferential wellbore trajectories to be achieved. This will enable development of geothermal wells with multi-lateral completions resulting in improved geothermal resource recovery, decreased environmental impact and enhanced well construction economics.

  1. NSTX High Temperature Sensor Systems

    International Nuclear Information System (INIS)

    McCormack, B.; Kugel, H.W.; Goranson, P.; Kaita, R.

    1999-01-01

    The design of the more than 300 in-vessel sensor systems for the National Spherical Torus Experiment (NSTX) has encountered several challenging fusion reactor diagnostic issues involving high temperatures and space constraints. This has resulted in unique miniature, high temperature in-vessel sensor systems mounted in small spaces behind plasma facing armor tiles, and they are prototypical of possible high power reactor first-wall applications. In the Center Stack, Divertor, Passive Plate, and vessel wall regions, the small magnetic sensors, large magnetic sensors, flux loops, Rogowski Coils, thermocouples, and Langmuir Probes are qualified for 600 degrees C operation. This rating will accommodate both peak rear-face graphite tile temperatures during operations and the 350 degrees C bake-out conditions. Similar sensor systems including flux loops, on other vacuum vessel regions are qualified for 350 degrees C operation. Cabling from the sensors embedded in the graphite tiles follows narrow routes to exit the vessel. The detailed sensor design and installation methods of these diagnostic systems developed for high-powered ST operation are discussed

  2. Development of high temperature turbine

    Energy Technology Data Exchange (ETDEWEB)

    Takahara, Kitao; Nouse, Hiroyuki; Yoshida, Toyoaki; Minoda, Mitsuhiro; Matsusue, Katsutoshi; Yanagi, Ryoji

    1988-07-01

    For the contribution to the development of FJR710, high by-pass ratio turbofan engine, with the study for many years of the development of high efficiency turbine for the jet engine, the first technical prize from the Energy Resource Research Committee was awarded in April, 1988. This report introduced its technical contents. In order to improve the thermal efficiency and enlarge the output, it is very effective to raise the gas temperature at the inlet of gas turbine. For its purpose, by cooling the nozzle and moving blades and having those blades operate at lower temperature than that of the working limitation, they realized, for the first time in Japan, the technique of cooling turbine to heighten the operational gas temperature. By that technique, it was enabled to raise the gas temperature at the inlet of turbine, to 1,350/sup 0/C from 850/sup 0/C. This report explain many important points of study covering the basic test, visualizing flow experiment, material discussion and structural design in the process of development. (9 figs)

  3. High temperature structural sandwich panels

    Science.gov (United States)

    Papakonstantinou, Christos G.

    High strength composites are being used for making lightweight structural panels that are being employed in aerospace, naval and automotive structures. Recently, there is renewed interest in use of these panels. The major problem of most commercial available sandwich panels is the fire resistance. A recently developed inorganic matrix is investigated for use in cases where fire and high temperature resistance are necessary. The focus of this dissertation is the development of a fireproof composite structural system. Sandwich panels made with polysialate matrices have an excellent potential for use in applications where exposure to high temperatures or fire is a concern. Commercial available sandwich panels will soften and lose nearly all of their compressive strength temperatures lower than 400°C. This dissertation consists of the state of the art, the experimental investigation and the analytical modeling. The state of the art covers the performance of existing high temperature composites, sandwich panels and reinforced concrete beams strengthened with Fiber Reinforced Polymers (FRP). The experimental part consists of four major components: (i) Development of a fireproof syntactic foam with maximum specific strength, (ii) Development of a lightweight syntactic foam based on polystyrene spheres, (iii) Development of the composite system for the skins. The variables are the skin thickness, modulus of elasticity of skin and high temperature resistance, and (iv) Experimental evaluation of the flexural behavior of sandwich panels. Analytical modeling consists of a model for the flexural behavior of lightweight sandwich panels, and a model for deflection calculations of reinforced concrete beams strengthened with FRP subjected to fatigue loading. The experimental and analytical results show that sandwich panels made with polysialate matrices and ceramic spheres do not lose their load bearing capability during severe fire exposure, where temperatures reach several

  4. Ceramics for high temperature applications

    International Nuclear Information System (INIS)

    Mocellin, A.

    1977-01-01

    Problems related to materials, their fabrication, properties, handling, improvements are examined. Silicium nitride and silicium carbide are obtained by vacuum hot-pressing, reaction sintering and chemical vapour deposition. Micrographs are shown. Mechanical properties i.e. room and high temperature strength, creep resistance fracture mechanics and fatigue resistance. Recent developments of pressureless sintered Si C and the Si-Al-O-N quaternary system are mentioned

  5. High-temperature geothermal cableheads

    Science.gov (United States)

    Coquat, J. A.; Eifert, R. W.

    1981-11-01

    Two high temperature, corrosion resistant logging cable heads which use metal seals and a stable fluid to achieve proper electrical terminations and cable sonde interfacings are described. A tensile bar provides a calibrated yield point, and a cone assembly anchors the cable armor to the head. Electrical problems of the sort generally ascribable to the cable sonde interface were absent during demonstration hostile environment loggings in which these cable heads were used.

  6. Application of Distributed Temperature Sensing for coupled mapping of sedimentation processes and spatio-temporal variability of groundwater discharge in soft-bedded streams

    DEFF Research Database (Denmark)

    Sebok, Eva; Duque, C; Engesgaard, Peter

    2015-01-01

    , maximum and mean streambed temperatures as well as the daily amplitude and standard deviation of temperatures. The identified potential high-discharge areas were mostly located near the channel banks, also showing temporal variability because of the scouring and redistribution of streambed sediments......The delineation of groundwater discharge areas based on Distributed Temperature Sensing (DTS) data of the streambed can be difficult in soft-bedded streams where sedimentation and scouring processes constantly change the position of the fibre optic cable relative to the streambed. Deposition...... variability in streambed temperatures between October 2011 and January 2012. Detailed monthly streambed elevation surveys were carried out to monitor the position of the fibre optic cable relative to the streambed and to quantify the effect of sedimentation processes on streambed temperatures. Based...

  7. Effect of temperature, hydraulic residence time and elevated PCO2 on acid neutralization within a pulsed limestone bed reactor

    Science.gov (United States)

    Watten, B.J.; Lee, P.C.; Sibrell, P.L.; Timmons, M.B.

    2007-01-01

    Limestone has potential for reducing reagent costs and sludge volume associated with treatment of acid mine drainage, but its use is restricted by slow dissolution rates and the deposition of Fe, Al and Mn-based hydrolysis products on reactive surfaces. We evaluated a pulsed limestone bed (PLB) reactor (15 L/min capacity) that uses a CO2 pretreatment step to accelerate dissolution and hydraulic shearing forces provided by intermittent fluidization to abrade and carry away surface scales. We established the effects of hydraulic residence time (HRT, 5.1-15.9 min), temperature (T, 12-22 ??C) and CO2 tension (PCO2, 34.5-206.8 kPa) on effluent quality when inlet acidity (Acy) was fixed at 440 mg/L (pH=2.48) with H2SO4. The PLB reactor neutralized all H+ acidity (N=80) while concurrently providing unusually high levels of effluent alkalinity (247-1028 mg/L as CaCO3) that allow for side-stream treatment with blending. Alkalinity (Alk) yields rose with increases in PCO2, HRT and settled bed height (BH, cm) and decreased with T following the relationship (R2=0.926; p<0.001): (Alk)non-filtered=-548.726+33.571??(PCO2)0.5+33.671??(HRT)+7.734??(BH)-5.197??(T). Numerical modeling showed CO2 feed requirements for a target Alk yield decrease with increases in HRT, T and the efficiency of off-gas (CO2) recycling. ?? 2007 Elsevier Ltd. All rights reserved.

  8. Nuclear graphite for high temperature reactors

    International Nuclear Information System (INIS)

    Marsden, B.J.

    2001-01-01

    The cores and reflectors in modern High Temperature Gas Cooled Reactors (HTRs) are constructed from graphite components. There are two main designs; the Pebble Bed design and the Prism design. In both of these designs the graphite not only acts as a moderator, but is also a major structural component that may provide channels for the fuel and coolant gas, channels for control and safety shut off devices and provide thermal and neutron shielding. In addition, graphite components may act as a heat sink or conduction path during reactor trips and transients. During reactor operation, many of the graphite component physical properties are significantly changed by irradiation. These changes lead to the generation of significant internal shrinkage stresses and thermal shut down stresses that could lead to component failure. In addition, if the graphite is irradiated to a very high irradiation dose, irradiation swelling can lead to a rapid reduction in modulus and strength, making the component friable.The irradiation behaviour of graphite is strongly dependent on its virgin microstructure, which is determined by the manufacturing route. Nevertheless, there are available, irradiation data on many obsolete graphites of known microstructures. There is also a well-developed physical understanding of the process of irradiation damage in graphite. This paper proposes a specification for graphite suitable for modern HTRs. (author)

  9. High temperature PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jianlu; Xie, Zhong; Zhang, Jiujun; Tang, Yanghua; Song, Chaojie; Navessin, Titichai; Shi, Zhiqing; Song, Datong; Wang, Haijiang; Wilkinson, David P.; Liu, Zhong-Sheng; Holdcroft, Steven [Institute for Fuel Cell Innovation, National Research Council Canada, Vancouver, BC (Canada V6T 1W5)

    2006-10-06

    There are several compelling technological and commercial reasons for operating H{sub 2}/air PEM fuel cells at temperatures above 100{sup o}C. Rates of electrochemical kinetics are enhanced, water management and cooling is simplified, useful waste heat can be recovered, and lower quality reformed hydrogen may be used as the fuel. This review paper provides a concise review of high temperature PEM fuel cells (HT-PEMFCs) from the perspective of HT-specific materials, designs, and testing/diagnostics. The review describes the motivation for HT-PEMFC development, the technology gaps, and recent advances. HT-membrane development accounts for {approx}90% of the published research in the field of HT-PEMFCs. Despite this, the status of membrane development for high temperature/low humidity operation is less than satisfactory. A weakness in the development of HT-PEMFC technology is the deficiency in HT-specific fuel cell architectures, test station designs, and testing protocols, and an understanding of the underlying fundamental principles behind these areas. The development of HT-specific PEMFC designs is of key importance that may help mitigate issues of membrane dehydration and MEA degradation. (author)

  10. Fluidized-bed calcination of simulated commercial high-level radioactive wastes

    International Nuclear Information System (INIS)

    Freeby, W.A.

    1975-11-01

    Work is in progress at the Idaho Chemical Processing Plant to verify process flowsheets for converting simulated commercial high-level liquid wastes to granular solids using the fluidized-bed calcination process. Primary emphasis in the series of runs reported was to define flowsheets for calcining simulated Allied-General Nuclear Services (AGNS) waste and to evaluate product properties significant to calcination, solids storage, or post treatment. Pilot-plant studies using simulated high-level acid wastes representative of those to be produced by Nuclear Fuel Services, Inc. (NFS) are also included. Combined AGNS high-level and intermediate-level waste (0.26 M Na in blend) was successfully calcined when powdered iron was added (to result in a Na/Fe mole ratio of 1.0) to the feed to prevent particle agglomeration due to sodium nitrate. Long-term runs (approximately 100 hours) showed that calcination of the combined waste is practical. Concentrated AGNS waste containing sodium at concentrations less than 0.2 M were calcined successfully; concentrated waste containing 1.13 M Na calcined successfully when powdered iron was added to the feed to suppress sodium nitrate formation. Calcination of dilute AGNS waste by conventional fluid-bed techniques was unsuccessful due to the inability to control bed particle size--both particle size and bed level decreased. Fluid-bed solidification of AGNS dilute waste at conditions in which most of the calcined solids left the calciner vessel with the off-gas was successful. In such a concept, the steady-state composition of the bed material would be approximately 22 wt percent calcined solids deposited on inert particles. Calcination of simulated NFS acid waste indicated that solidification by the fluid-bed process is feasible

  11. Temperature uniformity mapping in a high pressure high temperature reactor using a temperature sensitive indicator

    NARCIS (Netherlands)

    Grauwet, T.; Plancken, van der I.; Vervoort, L.; Matser, A.M.; Hendrickx, M.; Loey, van A.

    2011-01-01

    Recently, the first prototype ovomucoid-based pressure–temperature–time indicator (pTTI) for high pressure high temperature (HPHT) processing was described. However, for temperature uniformity mapping of high pressure (HP) vessels under HPHT sterilization conditions, this prototype needs to be

  12. Fluidised bed heat exchangers

    International Nuclear Information System (INIS)

    Elliott, D.E.; Healey, E.M.; Roberts, A.G.

    1974-01-01

    Problems that have arisen during the initial stages of development of fluidised bed boilers in which heat transfer surfaces are immersed in fluidised solids are discussed. The very high heat transfer coefficients that are obtained under these conditions can be exploited to reduce the total heat transfer surface to a fraction of that in normal boilers. However, with the high heat flux levels involved, tube stressing becomes more important and it is advantageous to use smaller diameter tubes. One of the initial problems was that the pumping power absorbed by the fluidised bed appeared to be high. The relative influence of the fluidising velocity (and the corresponding bed area), tube diameter, tube spacing, heat transfer coefficient and bed temperature on pumping power and overall cost was determined. This showed the importance of close tube packing and research was undertaken to see if this would adversely affect the heat transfer coefficient. Pressure operation also reduces the pumping power. Fouling and corrosion tests in beds burning coal suggest that higher temperatures could be reached reliably and cost studies show that, provided the better refractory metals are used, the cost of achieving higher temperatures is not unduly high. It now remains to demonstrate at large scale that the proposed systems are viable and that the methods incorporated to overcome start up and part lead running problems are satisfactory. The promising role of these heat transfer techniques in other applications is briefly discussed

  13. Temperature prediction in a coal fired boiler with a fixed bed by fuzzy logic based on numerical solution

    International Nuclear Information System (INIS)

    Biyikoglu, A.; Akcayol, M.A.; Oezdemir, V.; Sivrioglu, M.

    2005-01-01

    In this study, steady state combustion in boilers with a fixed bed has been investigated. Temperature distributions in the combustion chamber of a coal fired boiler with a fixed bed are predicted using fuzzy logic based on data obtained from the numerical solution method for various coal and air feeding rates. The numerical solution method and the discretization of the governing equations of two dimensional turbulent flow in the combustion chamber and one dimensional coal combustion in the fixed bed are explained. Control Volume and Finite Difference Methods are used in the discretization of the equations in the combustion chamber and in the fixed bed, respectively. Results are presented as contours within the solution domain and compared with numerical ones. Comparison of the results shows that the difference between the numerical solution and fuzzy logic prediction throughout the computational domain is less than 1.5%. The statistical coefficient of multiple determinations for the investigated cases is about 0.9993 to 0.9998. This accuracy degree is acceptable in predicting the temperature values. So, it can be concluded that fuzzy logic provides a feasible method for defining the system properties

  14. Reduced bed temperature at thermo-chemical conversion of difficult fuels; Saenkt baeddtemperatur vid termokemisk omvandling av svaara braenslen

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Fredrik; Haraldsson, Conny; Johansson, Andreas; Claesson, Frida; Baefver, Linda; Ryde, Daniel

    2010-05-15

    This work investigates the prospect of reducing the concentrations of alkali chlorides in the flue gas by lowering the temperature in the bottom zone of a fluidized bed (FB) furnace below the often used 850 deg C. The directive of a retention time of at least two seconds above 850 deg C is fulfilled by the raise of the flue gas temperature that follows the combustion of unburned gases at the point of injection of secondary and tertiary air, above the bottom bed zone. The aim of the present experiments is to determine the dependency between the temperature and the amount of alkali metals leaving the bottom bed for some selected waste and biomass fuels. The results are intended for plant owners as well as boiler manufacturers. The experiments were performed in an FB-reactor, which was externally heated to specific temperatures between 550 and 850 deg C. The reactor is made of a quartz glass tube with an inner diameter of 60 mm and a length of 1.2 m. The fluidized bed rests upon a porous plate of sintered quartz. The bed material used was 180 gram purified sea sand with particle sizes between 0.1 and 0.3 mm. The fluidizing gas was a mixture of nitrogen and air, introduced in the bottom of the reactor by mass flow controllers. At the outlet of the reactor, the flue gas was divided between conventional gas analyzers and an ICP-MS instrument. The gas flow to the ICP-MS instrument was cooled before a slip stream was sucked out via a capillary to a nebulizer from which the sample gas was led to the ICP-MS instrument. The function of the nebulizer is normally to form an aerosol of liquids, but here it was used solely as a pump. In addition, a known flow of krypton was added into the nebulizer to be used as an internal standard. The novel technique to measure the amount of alkali metals on-line from a batch fired FB-reactor has been shown to work in practice and to provide interesting results, which so far is qualitative only. Further development and calibration work is

  15. Hydrogen production from water gas shift reaction in a high gravity (Higee) environment using a rotating packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Hsin; Syu, Yu-Jhih [Department of Greenergy, National University of Tainan, Tainan 700 (China)

    2010-10-15

    Hydrogen production via the water gas shift reaction (WGSR) was investigated in a high gravity environment. A rotating packed bed (RPB) reactor containing a Cu-Zn catalyst and spinning in the range of 0-1800 rpm was used to create high centrifugal force. The reaction temperature and the steam/CO ratio ranged from 250 to 350 C and 2 to 8, respectively. A dimensionless parameter, the G number, was derived to account for the effect of centrifugal force on the enhancement of the WGSR. With the rotor speed of 1800 rpm, the induced centrifugal force acting on the reactants was as high as 234 g on average in the RPB. As a result, the CO conversion from the WGSR was increased up to 70% compared to that without rotation. This clearly revealed that the centrifugal force was conducive to hydrogen production, resulting from intensifying mass transfer and elongating the path of the reactants in the catalyst bed. From Le Chatelier's principle, a higher reaction temperature or a lower steam/CO ratio disfavors CO conversion; however, under such a situation the enhancement of the centrifugal force on hydrogen production from the WGSR tended to become more significant. Accordingly, a correlation between the enhancement of CO conversion and the G number was established. As a whole, the higher the reaction temperature and the lower the steam/CO ratio, the higher the exponent of the G number function and the better the centrifugal force on the WGSR. (author)

  16. Passivation of high temperature superconductors

    Science.gov (United States)

    Vasquez, Richard P. (Inventor)

    1991-01-01

    The surface of high temperature superconductors such as YBa2Cu3O(7-x) are passivated by reacting the native Y, Ba and Cu metal ions with an anion such as sulfate or oxalate to form a surface film that is impervious to water and has a solubility in water of no more than 10(exp -3) M. The passivating treatment is preferably conducted by immersing the surface in dilute aqueous acid solution since more soluble species dissolve into the solution. The treatment does not degrade the superconducting properties of the bulk material.

  17. CONFINEMENT OF HIGH TEMPERATURE PLASMA

    Science.gov (United States)

    Koenig, H.R.

    1963-05-01

    The confinement of a high temperature plasma in a stellarator in which the magnetic confinement has tended to shift the plasma from the center of the curved, U-shaped end loops is described. Magnetic means are provided for counteracting this tendency of the plasma to be shifted away from the center of the end loops, and in one embodiment this magnetic means is a longitudinally extending magnetic field such as is provided by two sets of parallel conductors bent to follow the U-shaped curvature of the end loops and energized oppositely on the inside and outside of this curvature. (AEC)

  18. High temperature superconductors and method

    International Nuclear Information System (INIS)

    Ruvalds, J.J.

    1977-01-01

    This invention comprises a superconductive compound having the formula: Ni/sub 1-x/M/sub x/Z/sub y/ wherein M is a metal which will destroy the magnetic character of nickel (preferably copper, silver or gold); Z is hydrogen or deuterium; x is 0.1 to 0.9; and y, correspondingly, 0.9 to 0.1, and method of conducting electric current with no resistance at relatively high temperature of T>1 0 K comprising a conductor consisting essentially of the superconducting compound noted above

  19. High temperature thermal energy storage in moving sand

    Science.gov (United States)

    Turner, R. H.; Awaya, H. I.

    1978-01-01

    Several high-temperature (to 500 C) heat-storage systems using sand as the storage medium are described. The advantages of sand as a storage medium include low cost for sand, widespread availability, non-toxicity, non-degradation characteristics, easy containment, and safety. The systems considered include: stationary sand with closely spaced tubes throughout the volume, the use of a fluidized bed, use of conveyor belt transporter, and the use of a blower rapid transport system. For a stationary sand bed, very close spacing of heat transfer tubes throughout the volume is required, manifesting as high power related system cost. The suggestion of moving sand past or around pipes is intended to reduce the power related costs at the penalty of added system complexity. Preliminary system cost estimates are offered. These rough calculations indicate that mobile sand heat storage systems cost less than the stationary sand approach.

  20. Development of high temperature gas cooled reactor in China

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Wentao [Paul Scherrer Institute, Villigen (Switzerland). Dept. of Nuclear Energy and Safety; Schorer, Michael [Swiss Nuclear Forum, Olten (Switzerland)

    2018-02-15

    High temperature gas cooled reactor (HTGR) is one of the six Generation IV reactor types put forward by Generation IV International Forum (GIF) in 2002. This type of reactor has high outlet temperature. It uses Helium as coolant and graphite as moderator. Pebble fuel and ceramic reactor core are adopted. Inherit safety, good economy, high generating efficiency are the advantages of HTGR. According to the comprehensive evaluation from the international nuclear community, HTGR has already been given the priority to the research and development for commercial use. A demonstration project of the High Temperature Reactor-Pebble-�bed Modules (HTR-PM) in Shidao Bay nuclear power plant in China is under construction. In this paper, the development history of HTGR in China and the current situation of HTR-PM will be introduced. The experiences from China may be taken as a reference by the international nuclear community.

  1. Modular high-temperature reactor launched (and wallchart)

    International Nuclear Information System (INIS)

    Steinwarz, W.

    1987-01-01

    In view of the need for a technically unsophisticated, safe and economic reactor system, the KWU group has integrated the experience gained from German light-water reactor engineering and from successful operation of the German AVR experimental high-temperature reactor into the development of the High-Temperature Reactor (HTR)-module. The main components are illustrated and explained and technical data for the HTR-module is given. Safety is also considered. This includes graphs of core heat-up temperature for pebble-bed HTR and a graph of the temperature load of the fuel elements. The operation, control and applications are considered. The latter includes use in combined heat and power generation and community heating. Feasibility studies have shown that the HTR-module is cheaper, comparatively, than coal-fired power stations. (U.K.)

  2. High Levels Of Bed Occupancy Associated With Increased Inpatient And Thirty-Day Hospital Mortality In Denmark

    DEFF Research Database (Denmark)

    Madsen, Flemming; Ladelund, Steen; Linneberg, Allan

    2014-01-01

    to low bed occupancy rates. Being admitted to a hospital outside of normal working hours or on a weekend or holiday was also significantly associated with increased mortality. The health risks of bed shortages, including mortality, could be better documented as a priority health issue. Resources should......High bed occupancy rates have been considered a matter of reduced patient comfort and privacy and an indicator of high productivity for hospitals. Hospitals with bed occupancy rates of above 85 percent are generally considered to have bed shortages. Little attention has been paid to the impact...... be allocated to researching the causes and effects of bed shortages, with the aim of creating greater interest in exploring new methods to avoid or reduce bed shortages....

  3. Application of a high density adsorbent in expanded bed adsorption ...

    African Journals Online (AJOL)

    PRECIOUS

    2010-01-11

    Jan 11, 2010 ... bent, the EBA process can be performed at high flow velocity or high particulate ... were done by (Gao et al., 2007) for understanding the interaction ..... used was not strong enough to dissociate hydrophobic bond presence or ...

  4. Modern high-temperature superconductivity

    International Nuclear Information System (INIS)

    Ching Wu Chu

    1988-01-01

    Ever since the discovery of superconductivity in 1911, its unusual scientific challenge and great technological potential have been recognized. For the past three-quarters of a century, superconductivity has done well on the science front. This is because sueprconductivity is interesting not only just in its own right but also in its ability to act as a probe to many exciting nonsuperconducting phenomena. For instance, it has continued to provide bases for vigorous activities in condensed matter science. Among the more recent examples are heavy-fermion systems and organic superconductors. During this same period of time, superconductivity has also performed admirably in the applied area. Many ideas have been conceived and tested, making use of the unique characteristics of superconductivity - zero resistivity, quantum interference phenomena, and the Meissner effect. In fact, it was not until late January 1987 that it became possible to achieve superconductivity with the mere use of liquid nitrogen - which is plentiful, cheap, efficient, and easy to handle - following the discovery of supercondictivity above 90 K in Y-Ba-Cu-O, the first genuine quaternary superconductor. Superconductivity above 90 K poses scientific and technological challenges not previously encountered: no existing theories can adequately describe superconductivity above 40 K and no known techniques can economically process the materials for full-scale applications. In this paper, therefore, the author recalls a few events leading to the discovery of the new class of quaternary compounds with a superconducting transition temperature T c in the 90 K range, describes the current experimental status of high-temperature superconductivity and, finally, discusses the prospect of very-high-temperature superconductivity, i.e., with a T c substantially higher than 100 K. 97 refs., 7 figs

  5. Bed rest from the perspective of the high-risk pregnant woman.

    Science.gov (United States)

    Gupton, A; Heaman, M; Ashcroft, T

    1997-01-01

    To describe the experience of prolonged bed rest from the perspective of women during high-risk pregnancies. A focused ethnographic study that used interviews, participant diaries, and field notes as data sources. Participants were obtained from an acute-care hospital antepartum unit and an antepartum home care program. Twenty-four women with complications of pregnancy requiring prolonged bed rest (range, 7-50 days). A model of the stress process in pregnant women on bed rest emerged from the data analysis. Stressors were grouped into situational (sick role, lack of control, uncertainty, concerns regarding fetus's well-being, and being tired of waiting), environmental (feeling like a prisoner, being bored, and having a sense of missing out), and family (role reversal and worry about older children) categories. Two main mediators of stress were social support and coping. Families, friends, and professionals were perceived as sources of support. Women used coping strategies, such as keeping a positive attitude, taking it 1 day at a time, doing it for the baby, getting used to it, setting goals, and keeping busy. Manifestations of stress were evidenced by adverse physical symptoms, emotional reactions, and altered social relationships. Prolonged bed rest is a stressful experience for pregnant women at high risk. Understanding the stress process in pregnant women confined to bed rest may assist nurses in developing interventions to reduce stressors and enhance mediators.

  6. Studies of high temperature superconductors

    International Nuclear Information System (INIS)

    Narlikar, A.

    1989-01-01

    The high temperature superconductors (HTSCs) discovered are from the family of ceramic oxides. Their large scale utilization in electrical utilities and in microelectronic devices are the frontal challenges which can perhaps be effectively met only through consolidated efforts and expertise of a multidisciplinary nature. During the last two years the growth of the new field has occurred on an international scale and perhaps has been more rapid than in most other fields. There has been an extraordinary rush of data and results which are continually being published as short texts dispersed in many excellent journals, some of which were started to ensure rapid publication exclusively in this field. As a result, the literature on HTSCs has indeed become so massive and so diffuse that it is becoming increasingly difficult to keep abreast with the important and reliable facets of this fast-growing field. This provided the motivation to evolve a process whereby both professional investigators and students can have ready access to up-to- date in-depth accounts of major technical advances happening in this field. The present series Studies of High Temperature Superconductors has been launched to, at least in part, fulfill this need

  7. High temperature superconductor current leads

    International Nuclear Information System (INIS)

    Zeimetz, B.; Liu, H.K.; Dou, S.X.

    1996-01-01

    Full text: The use of superconductors in high electrical current applications (magnets, transformers, generators etc.) usually requires cooling with liquid Helium, which is very expensive. The superconductor itself produces no heat, and the design of Helium dewars is very advanced. Therefore most of the heat loss, i.e. Helium consumption, comes from the current lead which connects the superconductor with its power source at room temperature. The current lead usually consists of a pair of thick copper wires. The discovery of the High Temperature Superconductors makes it possible to replace a part of the copper with superconducting material. This drastically reduces the heat losses because a) the superconductor generates no resistive heat and b) it is a very poor thermal conductor compared with the copper. In this work silver-sheathed superconducting tapes are used as current lead components. The work comprises both the production of the tapes and the overall design of the leads, in order to a) maximize the current capacity ('critical current') of the superconductor, b) minimize the thermal conductivity of the silver clad, and c) optimize the cooling conditions

  8. Container floor at high temperatures

    International Nuclear Information System (INIS)

    Reutler, H.; Klapperich, H.J.; Mueller-Frank, U.

    1978-01-01

    The invention describes a floor for container which is stressed at high, changing temperatures and is intended for use in gas-cooled nuclear reactors. Due to the downward cooling gas flow in these types of reactor, the reactor floor is subjected to considerable dimensional changes during switching on and off. In the heating stage, the whole graphite structure of the reactor core and floor expands. In order to avoid arising constraining forces, sufficiently large expansion spaces must be allowed for furthermore restoring forces must be present to close the gaps again in the cooling phase. These restoring forces must be permanently present to prevent loosening of the core cuits amongst one another and thus uncontrollable relative movement. Spring elements are not suitable due to fast fatigue as a result of high temperatures and radiation exposure. It is suggested to have the floor elements supported on rollers whose rolling planes are downwards inclined to a fixed point for support. The construction is described in detail by means of drawings. (GL) [de

  9. High Temperature Radio Frequency Loads

    CERN Document Server

    Federmann, S; Grudiev, A; Montesinos, E; Syratchev, I

    2011-01-01

    In the context of energy saving and recovery requirements the design of reliable and robust RF power loads which permit a high outlet temperature and high pressure of the cooling water is desirable. Cooling water arriving at the outlet withmore than 150 ◦C and high pressure has a higher value than water with 50 ◦C under low pressure. Conventional RF power loads containing dielectric and magnetic materials as well as sensitive ceramic windows usually do not permit going much higher than 90 ◦C. Here we present and discuss several design concepts for "metal only" RF high power loads. One concept is the application of magnetic steel corrugated waveguides near cutoff – this concept could find practical use above several GHz. Another solution are resonant structures made of steel to be installed in large waveguides for frequencies of 500 MHz or lower. Similar resonant structures above 100 MHz taking advantage of the rather high losses of normal steel may also be used in coaxial line geometries with large di...

  10. High concentration agglomerate dynamics at high temperatures.

    Science.gov (United States)

    Heine, M C; Pratsinis, S E

    2006-11-21

    The dynamics of agglomerate aerosols are investigated at high solids concentrations that are typical in industrial scale manufacture of fine particles (precursor mole fraction larger than 10 mol %). In particular, formation and growth of fumed silica at such concentrations by chemical reaction, coagulation, and sintering is simulated at nonisothermal conditions and compared to limited experimental data and commercial product specifications. Using recent chemical kinetics for silica formation by SiCl4 hydrolysis and neglecting aerosol polydispersity, the evolution of the diameter of primary particles (specific surface area, SSA), hard- and soft-agglomerates, along with agglomerate effective volume fraction (volume occupied by agglomerate) is investigated. Classic Smoluchowski theory is fundamentally limited for description of soft-agglomerate Brownian coagulation at high solids concentrations. In fact, these high concentrations affect little the primary particle diameter (or SSA) but dominate the soft-agglomerate diameter, structure, and volume fraction, leading to gelation consistent with experimental data. This indicates that restructuring and fragmentation should affect product particle characteristics during high-temperature synthesis of nanostructured particles at high concentrations in aerosol flow reactors.

  11. Effect of heat bed temperature of 3D bioprinter to hardness and compressive strength of scaffold bovine hydroxyapatite

    Science.gov (United States)

    Triyono, Joko; Pratama, Aditya; Sukanto, Heru; Nugroho, Yohanes; Wijayanta, Agung Tri

    2018-02-01

    This study aimed to investigate the effect of heat bed temperature of 3D bioprinter toward compressive strength and hardness bovine bone hydroxyapatite scaffold for bone filler applications. BHA-glycerin mixed with a ratio of 1:1, and keep it for 24 hours. After the homogenization process acquired, bio-Ink with shaped slurry will be used as a material for a 3D printer. The printing process with a temperature variation have performed by setting up heat bed temperature. After printing process was completed, the 3D scaffold was detained on the heat bed for 10 minutes before being picked up. The test results in this study had the lowest hardness value of 9.82±0.62 VHN and the highest number of 24.32±0.99 VHN. The compressive strength testing had the lowest value of 1.62±0.16 MPa with the highest number of 5.67±0.39 MPa. Pore observation using a scanning electron microscope. The result shows that the size of the pores were not much different, that was ±100-200 µm. This observation also indicated that the pore form was square pores.

  12. METHOD OF CALCULATION OF THE NON-STATIONARY TEMPERATURE FIELD INSIDE OF THERMAL PACKED BED ENERGY STORAGE

    Directory of Open Access Journals (Sweden)

    Ermuratschii V.V.

    2014-04-01

    Full Text Available e paper presents a method of the approximate calculation of the non-stationary temperature field inside of thermal packed bed energy storages with feasible and latent heat. Applying thermoelectric models and computational methods in electrical engineering, the task of computing non-stationary heat transfer is resolved with respect to third type boundary conditions without applying differential equations of the heat transfer. For sub-volumes of the energy storage the method is executed iteratively in spatiotemporal domain. Single-body heating is modeled for each sub-volume, and modeling conditions are assumed to be identical for remained bod-ies, located in the same sub-volume. For each iteration step the boundary conditions will be represented by re-sults at the previous step. The fulfillment of the first law of thermodynamics for system “energy storage - body” is obtained by the iterative search of the mean temperature of the energy storage. Under variable boundary con-ditions the proposed method maybe applied to calculating temperature field inside of energy storages with packed beds consisted of solid material, liquid and phase-change material. The method may also be employed to compute transient, power and performance characteristics of packed bed energy storages.

  13. High-Temperature Thermal Energy Storage for electrification and district heating

    DEFF Research Database (Denmark)

    Pedersen, A. Schrøder; Engelbrecht, K.; Soprani, S.

    stability upon thermal cycling. The most promising material consists of basalt, diabase, and magnetite, whereas the less suited rocks contain larger proportions of quartz and mica. An HT-TES system, containing 1.5 m3 of rock pieces, was constructed. The rock bed was heated to 600 ˚C using an electric heater......The present work describes development of a High Temperature Thermal Energy Storage (HT-TES) system based on rock bed technology. A selection of rocks was investigated by thermal analysis in the range 20-800 ˚C. Subsequently, a shortlist was defined primarily based on mechanical and chemical...... to simulate thermal charging from wind energy. After complete heating of the rock bed it was left fully charged for hours to simulate actual storage conditions. Subsequently the bed discharging was performed by leading cold air through the rock bed whereby the air was heated and led to an exhaust. The results...

  14. High Temperature Superconductor Accelerator Magnets

    CERN Document Server

    AUTHOR|(CDS)2079328; de Rijk, Gijs; Dhalle, Marc

    2016-11-10

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding $20T$. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and development before they can be applied in a practical accelerator magnet. In order to study HTS in detail, a five tesla demonstrator magnet named Feather-M2 is designed and constructed. The magnet is based on ReBCO coated conductor, which is assembled into a $10kA$ class Roebel cable. A new and optimized Aligned Block layout is used, which takes advantage of the anisotropy of the conductor. This is achieved by providing local alignment of the Roebel cable in the coil windings with the magnetic field lines. A new Network Model capable of analyzing transient electro-magnetic and thermal phenomena in coated conductor cables and coils is developed. This model is necessary to solve critical issues in coated conductor ac...

  15. High temperature industrial heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Berghmans, J. (Louvain Univ., Heverlee (Belgium). Inst. Mechanica)

    1990-01-01

    The present report intends to describe the state of the art of high temperature industrial heat pumps. A description is given of present systems on the market. In addition the research and development efforts on this subject are described. Compression (open as well as closed cycle) systems, as well as absorption heat pumps (including transformers), are considered. This state of the art description is based upon literature studies performed by a team of researchers from the Katholieke Universiteit Leuven, Belgium. The research team also analysed the economics of heat pumps of different types under the present economic conditions. The heat pumps are compared with conventional heating systems. This analysis was performed in order to evaluate the present condition of the heat pump in the European industry.

  16. Faraday imaging at high temperatures

    Science.gov (United States)

    Hackel, Lloyd A.; Reichert, Patrick

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid.

  17. Faraday imaging at high temperatures

    International Nuclear Information System (INIS)

    Hackel, L.A.; Reichert, P.

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid. 3 figs

  18. High School Students’ Use of Sunscreen and Tanning Beds

    Centers for Disease Control (CDC) Podcasts

    This podcast is an interview with Corey Basch, EdD, MPH, assistant professor in the Department of Public Health at William Paterson University. Dr. Basch discusses her study on high school students’ use of sunscreen and tanning beds between 2001 and 2011.

  19. High temperature incineration. Densification of granules from high temperature incineration

    International Nuclear Information System (INIS)

    Voorde, N. van de; Claes, J.; Taeymans, A.; Hennart, D.; Gijbels, J.; Balleux, W.; Geenen, G.; Vangeel, J.

    1982-01-01

    The incineration system of radioactive waste discussed in this report, is an ''integral'' system, which directly transforms a definite mixture of burnable and unburnable radioactive waste in a final product with a sufficient insolubility to be safely disposed of. At the same time, a significant volume reduction occurs by this treatment. The essential part of the system is a high temperature incinerator. The construction of this oven started in 1974, and while different tests with simulated inactive or very low-level active waste were carried out, the whole system was progressively and continuously extended and adapted, ending finally in an installation with completely remote control, enclosed in an alpha-tight room. In this report, a whole description of the plant and of its auxiliary installations will be given; then the already gained experimental results will be summarized. Finally, the planning for industrial operation will be briefly outlined. An extended test with radioactive waste, which was carried out in March 1981, will be discussed in the appendix

  20. Effects of Temperature and Residence Time on the Emissions of PIC and Fine Particles during Fixed Bed Combustion of Conifer Stemwood Pellets

    Energy Technology Data Exchange (ETDEWEB)

    Boman, Christoffer; Lindmark, Fredrik; Oehman, Marcus; Nordin, Anders [Umeaa Univ. (Sweden). Energy Technology and Thermal Process Chemistry; Pettersson, Esbjoern [Energy Technology Centre, Piteaa (Sweden); Westerholm, Roger [Stockholm Univ., Arrhenius Laboratory (Sweden). Dept. of Analytical Chemistry

    2006-07-15

    The use of wood fuel Pellets has proved to be well suited for the small-scale market enabling controlled and efficient combustion with low emission of products of incomplete combustion (PIC). Still a potential for further emission reduction exists and a thorough understanding of the influence of combustion conditions on the emission characteristics of air pollutants like PAH and particulate matter (PM) is important. The objective was to determine the effects of temperature and residence time on the emission performance and characteristics with focus on hydrocarbons and PM during combustion of conifer stemwood Pellets in a laboratory fixed bed reactor (<5 kW). Temperature and residence time after the bed section were varied according to statistical experimental designs (650-970 deg C and 0.5-3.5 s) with the emission responses; CO, organic gaseous carbon, NO, 20 VOC compounds, 43 PAH compounds, PM{sub tot}, fine particle mass/count median diameter (MMD and CMD) and number concentration. Temperature was negatively correlated with the emissions of all studied PIC with limited effects of residence time. The PM{sub tot} emissions of 15-20 mg/MJ was in all cases dominated by fine (<1 {mu}m) particles of K, Na, S, Cl, C, O and Zn. Increased residence time resulted in increased fine particle sizes (i.e. MMD and CMD) and decreased number concentrations. The importance of high temperature (>850 deg C) in the bed zone with intensive, air rich and well mixed isothermal conditions for 0.5-1.0 s in the post combustion zone was illustrated for wood Pellets combustion with almost a total depletion of all studied PIC. The results emphasize the need for further verification studies and technology development work.

  1. Accelerated carbonation of steelmaking slags in a high-gravity rotating packed bed

    International Nuclear Information System (INIS)

    Chang, E-E; Pan, Shu-Yuan; Chen, Yi-Hung; Tan, Chung-Sung; Chiang, Pen-Chi

    2012-01-01

    Highlights: ► The carbonation conversion in a RPB was higher than that in traditional reactors. ► The optimum conditions were operated at 750 rpm and 65 °C for 30 min. ► The product on BOF slag was identified as crystallized calcite based on SEM and XRD. ► The diffusivity ranged from 10 −7 to 10 −6 cm 2 s −1 based on the shrinking core model. - Abstract: Carbon dioxide (CO 2 ) sequestration using the accelerated carbonation of basic oxygen furnace (BOF) slag in a high-gravity rotating packed bed (RPB) under various operational conditions was investigated. The effects of reaction time, reaction temperature, rotation speed and slurry flow rate on the CO 2 sequestration process were evaluated. The samples of reacted slurry were analyzed quantitatively using thermogravimetric analysis (TGA) and atomic absorption spectrometry (AAS) and qualitatively using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and transmission electron microscopy (TEM). The sequestration experiments were performed at a liquid-to-solid ratio of 20:1 with a flow rate of 2.5 L min −1 of a pure CO 2 stream under atmospheric temperature and pressure. The results show that a maximum conversion of BOF slag was 93.5% at a reaction time of 30 min and a rotation speed of 750 rpm at 65 °C. The experimental data were utilized to determine the rate-limiting mechanism based on the shrinking core model (SCM), which was validated by the observations of SEM and TEM. Accelerated carbonation in a RPB was confirmed to be a viable method due to its higher mass-transfer rate.

  2. The Metabolic Cost of a High Intensity Exercise Program During Bed Rest

    Science.gov (United States)

    Hackney, Kyle; Everett, Meghan; Guined, Jamie; Cunningham, Daid

    2012-01-01

    Background: Given that disuse-related skeletal muscle atrophy may be exacerbated by an imbalance between energy intake and output, the amount of energy required to complete exercise countermeasures is an important consideration in the well being of subject health during bed rest and spaceflight. Objective: To evaluate the energy cost of a high intensity exercise program performed during short duration bed rest. Methods: 9 subjects (8 male and 1 female; 34.5 +/- 8.2 years) underwent 14 days of bed rest and exercise countermeasures. Exercise energy expenditure and excess post exercise oxygen consumption (EPOC) were collected once in each of 5 different exercise protocols (30 second, 2 minute and 4 minute intervals, continuous aerobic and a variety of resistance exercises) during bed rest. Body mass, basal metabolic rate (BMR), upper and lower leg muscle, subcutaneous, and intramuscular adipose tissue (IMAT) volumes were assessed before and at the end of bed rest. Results: There were no significant differences in body mass (pre: 75.1 +/- 10.5 kg; post: 75.2 +/- 10.1 kg), BMR (pre: 1649 +/- 216 kcal; post: 1657 +/- 177 kcal), muscle subcutaneous, or IMAT volumes (Table 2) after 14 days of bed rest and exercise. Body mass was maintained with an average daily intake of 2710 +/- 262 kcal (36.2 +/- 2.1 kcal/kg/day), while average daily energy expenditure was 2579 +/-311 kcal (34.5 +/- 3.6 kcal/kg/day). Exercise energy expenditure was significantly greater as a result of continuous aerobic exercise than all other exercise protocols.

  3. Latitude, temperature, and habitat complexity predict predation pressure in eelgrass beds across the Northern Hemisphere.

    Science.gov (United States)

    Reynolds, Pamela L; Stachowicz, John J; Hovel, Kevin; Boström, Christoffer; Boyer, Katharyn; Cusson, Mathieu; Eklöf, Johan S; Engel, Friederike G; Engelen, Aschwin H; Eriksson, Britas Klemens; Fodrie, F Joel; Griffin, John N; Hereu, Clara M; Hori, Masakazu; Hanley, Torrance C; Ivanov, Mikhail; Jorgensen, Pablo; Kruschel, Claudia; Lee, Kun-Seop; McGlathery, Karen; Moksnes, Per-Olav; Nakaoka, Masahiro; O'Connor, Mary I; O'Connor, Nessa E; Orth, Robert J; Rossi, Francesca; Ruesink, Jennifer; Sotka, Erik E; Thormar, Jonas; Tomas, Fiona; Unsworth, Richard K F; Whalen, Matthew A; Duffy, J Emmett

    2018-01-01

    Latitudinal gradients in species interactions are widely cited as potential causes or consequences of global patterns of biodiversity. However, mechanistic studies documenting changes in interactions across broad geographic ranges are limited. We surveyed predation intensity on common prey (live amphipods and gastropods) in communities of eelgrass (Zostera marina) at 48 sites across its Northern Hemisphere range, encompassing over 37° of latitude and four continental coastlines. Predation on amphipods declined with latitude on all coasts but declined more strongly along western ocean margins where temperature gradients are steeper. Whereas in situ water temperature at the time of the experiments was uncorrelated with predation, mean annual temperature strongly positively predicted predation, suggesting a more complex mechanism than simply increased metabolic activity at the time of predation. This large-scale biogeographic pattern was modified by local habitat characteristics; predation declined with higher shoot density both among and within sites. Predation rates on gastropods, by contrast, were uniformly low and varied little among sites. The high replication and geographic extent of our study not only provides additional evidence to support biogeographic variation in predation intensity, but also insight into the mechanisms that relate temperature and biogeographic gradients in species interactions. © 2017 by the Ecological Society of America.

  4. Fluidized bed gasification of high tonnage sorghum, cotton gin trash and beef cattle manure: Evaluation of synthesis gas production

    International Nuclear Information System (INIS)

    Maglinao, Amado L.; Capareda, Sergio C.; Nam, Hyungseok

    2015-01-01

    Highlights: • High tonnage sorghum, cotton gin trash and beef cattle manure were characterized and gasified in a fluidized bed reactor. • Biomass gasification at 730 °C and ER = 0.35 produced synthesis gas with an average energy content of 4.19 MJ Nm −3 . • Synthesis gas heating value and yield were relatively constant at reaction temperatures from 730 °C to 800 °C. • Optimum hydrogen production on HTS gasification was achieved at 780 °C temperature and ER of 0.4. - Abstract: Fluidized bed gasification using high-tonnage sorghum, cotton gin trash and beef cattle manure was performed in a pilot scale bubbling fluidized bed reactor equipped with the necessary feedback control system. Characterization of biomass showed that the high-tonnage sorghum had the highest energy and carbon content of 19.58 MJ kg −1 and 42.29% wt , respectively among the three feed stocks. At 730 °C reaction temperature and equivalence ratio of 0.35, comparable yields of methane, nitrogen and carbon dioxide (within ± 1.4% vol ) were observed in all three feed stocks. The gasification system produced synthesis gas with an average heating value of 4.19 ± 0.09 MJ Nm −3 and an average yield of 1.98 ± 0.1 Nm 3 kg −1 of biomass. Carbon conversion and gasification efficiencies indicated that most of the carbon was converted to gaseous products (85% average ) while 48% average of the energy from the biomass was converted into combustible gas. The production of hydrogen was significantly affected by the biomass used during gasification. The synthesis gas heating value and yield were relatively constant at reaction temperatures from 730 °C to 800 °C. Utilizing high-tonnage sorghum, the optimum hydrogen production during gasification was achieved at a reaction temperature of 780 °C and an equivalence ratio of 0.40.

  5. Unsteady void measurements within debris beds using high speed X-ray tomography

    Energy Technology Data Exchange (ETDEWEB)

    Laurien, E., E-mail: Laurien@ike.uni-stuttgart.de; Stürzel, T., E-mail: thilo.stuerzel@stihl.de; Zhou, M., E-mail: mi.zhou@ike.uni-stuttgart.de

    2017-02-15

    Highlights: • A high speed X-ray tomography facility has been built for the investigation on two-phase flow. • The two-phase flow through beds of packed plastic spheres has been investigated in the facility. • 3D-reconstructions from the measurements show the fluxes in the two-phase flow. • The gas fraction has been calculated from the reconstruction and used for validation of the modeling. • A new bed with closest regular spheres arrangement has been manufactured by 3D-plotter and used in the measurement. - Abstract: Two-phase flow and boiling within debris beds representing a destroyed reactor core after a severe accident with core fragmentation can be simulated by using the porous media approach. In this approach, a local pressure drop and the heat transfer between the solid debris particles and the two-phase flow is modelled with the help flow-pattern maps, in which the boundaries between bubbly, slug, and annular flow are assumed. In order to support further understanding of these flows we have developed a very fast X-ray measurement device to visualize the 3D-void distribution within particle beds or porous media, which are otherwise un-accessible internally. The experimental setup uses a scanned electron beam directed in circles on a tungsten target to generate the X-rays. The particle bed, which has a diameter of 70 mm, is located between this target and a field of 256 X-ray detectors, which are arranged on a circle concentric to the target. The void distribution is reconstructed numerically from the attenuation of signals, which penetrates the particle bed and the two-phase flow inside. A 3D frame rate of up to 1000 Hz can be reached. The spatial resolution is such that bubbles with a diameter > 1.7 mm can be detected. We have investigated two-phase flows air/water through beds of packed plastic spheres (diameter between 3 and 15 mm) as well as through plastic beds, which were manufactured using a ‘3D-plotter’. Flow patterns can be

  6. High Temperature Superconducting Underground Cable

    International Nuclear Information System (INIS)

    Farrell, Roger A.

    2010-01-01

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the worlds first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  7. High-temperature axion potential

    International Nuclear Information System (INIS)

    Dowrick, N.J.; McDougall, N.A.

    1989-01-01

    We investigate the possibility of new terms in the high-temperature axion potential arising from the dynamical nature of the axion field and from higher-order corrections to the θ dependence in the free energy of the quark-gluon plasma. We find that the dynamical nature of the axion field does not affect the potential but that the higher-order effects lead to new terms in the potential which are larger than the term previously considered. However, neither the magnitude nor the sign of the potential can be calculated by a perturbative expansion of the free energy since the coupling is too large. We show that a change in the magnitude of the potential does not significantly affect the bound on the axion decay constant but that the sign of the potential is of crucial importance. By investigating the formal properties of the functional integral within the instanton dilute-gas approximation, we find that the sign of the potential does not change and that the minimum remains at θ=0. We conclude that the standard calculation of the axion energy today is not significantly modified by this investigation

  8. Creep of high temperature composites

    International Nuclear Information System (INIS)

    Sadananda, K.; Feng, C.R.

    1993-01-01

    High temperature creep deformation of composites is examined. Creep of composites depends on the interplay of many factors. One of the basic issues in the design of the creep resistant composites is the ability to predict their creep behavior from the knowledge of the creep behavior of the individual components. In this report, the existing theoretical models based on continuum mechanics principles are reviewed. These models are evaluated using extensive experimental data on molydisilicide-silicon carbide composites obtained by the authors. The analysis shows that the rule of mixture based on isostrain and isostress provides two limiting bounds wherein all other theoretical predictions fall. For molydisilicide composites, the creep is predominantly governed by the creep of the majority phase, i.e. the matrix with fibers deforming elastically. The role of back stresses both on creep rates and activation energies are shown to be minimum. Kinetics of creep in MoSi 2 is shown to be controlled by the process of dislocation glide with climb involving the diffusion of Mo atoms

  9. Heat exchangers for high-temperature thermodynamic cycles

    International Nuclear Information System (INIS)

    Fraas, A.P.

    1975-01-01

    The special requirements of heat exchangers for high temperature thermodynamic cycles are outlined and discussed with particular emphasis on cost and thermal stress problems. Typical approaches that have been taken to a comprehensive solution intended to meet all of the many boundary conditions are then considered by examining seven typical designs including liquid-to-liquid heat exchangers for nuclear plants, a heater for a closed cycle gas turbine coupled to a fluidized bed coal combustion chamber, steam generators for nuclear plants, a fossil fuel-fired potassium boiler, and a potassium condenser-steam generator. (auth)

  10. High Temperature Chemistry at NASA: Hot Topics

    Science.gov (United States)

    Jacobson, Nathan S.

    2014-01-01

    High Temperature issues in aircraft engines Hot section: Ni and Co based Superalloys Oxidation and Corrosion (Durability) at high temperatures. Thermal protection system (TPS) and RCC (Reinforced Carbon-Carbon) on the Space Shuttle Orbiter. High temperatures in other worlds: Planets close to their stars.

  11. High temperature vapors science and technology

    CERN Document Server

    Hastie, John

    2012-01-01

    High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

  12. Evaluation of high temperature pressure sensors

    International Nuclear Information System (INIS)

    Choi, In-Mook; Woo, Sam-Yong; Kim, Yong-Kyu

    2011-01-01

    It is becoming more important to measure the pressure in high temperature environments in many industrial fields. However, there is no appropriate evaluation system and compensation method for high temperature pressure sensors since most pressure standards have been established at room temperature. In order to evaluate the high temperature pressure sensors used in harsh environments, such as high temperatures above 250 deg. C, a specialized system has been constructed and evaluated in this study. The pressure standard established at room temperature is connected to a high temperature pressure sensor through a chiller. The sensor can be evaluated in conditions of changing standard pressures at constant temperatures and of changing temperatures at constant pressures. According to the evaluation conditions, two compensation methods are proposed to eliminate deviation due to sensitivity changes and nonlinear behaviors except thermal hysteresis.

  13. Characterization of fluidization regime in circulating fluidized bed reactor with high solid particle concentration using computational fluid dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Chalermsinsuwan, Benjapon; Thummakul, Theeranan; Piumsomboon, Pornpote [Chulalongkorn University, Bangkok (Thailand); Gidaspow, Dimitri [Armour College of Engineering, Chicago (United States)

    2014-02-15

    The hydrodynamics inside a high solid particle concentration circulating fluidized bed reactor was investigated using computational fluid dynamics simulation. Compared to a low solid particle reactor, all the conventional fluidization regimes were observed. In addition, two unconventional fluidization regimes, circulating-turbulent and dense suspension bypassing regimes, were found with only primary gas injection. The circulating-turbulent fluidization regime showed uniformly dense solid particle distribution in all the system directions, while the dense suspension bypassing fluidization regime exhibited the flow of solid particles at only one side system wall. Then, comprehensive fluidization regime clarification and mapping were evaluated using in-depth system parameters. In the circulating-turbulent fluidization regime, the total granular temperature was low compared to the adjacent fluidization regimes. In the dense suspension bypassing fluidization regime, the highest total granular temperature was obtained. The circulating-turbulent and dense suspension bypassing fluidization regimes are suitable for sorption and transportation applications, respectively.

  14. High temperature nuclear heat for isothermal reformer

    International Nuclear Information System (INIS)

    Epstein, M.

    2000-01-01

    High temperature nuclear heat can be used to operate a reformer with various feedstock materials. The product synthesis gas can be used not only as a source for hydrogen and as a feedstock for many essential chemical industries, such as ammonia and other products, but also for methanol and synthetic fuels. It can also be burnt directly in a combustion chamber of a gas turbine in an efficient combined cycle and generate electricity. In addition, it can be used as fuel for fuel cells. The reforming reaction is endothermic and the contribution of the nuclear energy to the calorific value of the final product (synthesis gas) is about 25%, compared to the calorific value of the feedstock reactants. If the feedstock is from fossil origin, the nuclear energy contributes to a substantial reduction in CO 2 emission to the atmosphere. The catalytic steam reforming of natural gas is the most common process. However, other feedstock materials, such as biogas, landfill gas and CO 2 -contaminated natural gas, can be reformed as well, either directly or with the addition of steam. The industrial steam reformers are generally fixed bed reactors, and their performance is strongly affected by the heat transfer from the furnace to the catalyst tubes. In top-fired as well as side-fired industrial configurations of steam reformers, the radiation is the main mechanism of heat transfer and convection heat transfer is negligible. The flames and the furnace gas constitute the main sources of the heat. In the nuclear reformers developed primarily in Germany, in connection with the EVA-ADAM project (closed cycle), the nuclear heat is transferred from the nuclear reactor coolant gas by convection, using a heating jacket around the reformer tubes. In this presentation it is proposed that the helium in a secondary loop, used to cool the nuclear reactor, will be employed to evaporate intermediate medium, such as sodium, zinc and aluminum chloride. Then, the vapors of the medium material transfer

  15. Investigation on catalytic gasification of high-ash coal with mixing-gas in a small-scale fluidised bed

    Energy Technology Data Exchange (ETDEWEB)

    Chen, X.; Zhang, J.; Lin, J. [Fuzhou University, Fuzhou (China)

    2005-10-15

    The experimental study on the Yangquan high-ash coal catalytic gasification with mixing gas by using solid alkali or waste liquid of viscose fiber as the catalyst in a small-scale fluidized bed with 28 mm i.d. was carried out. The loading saturation levels of two catalysts in Yangquan high-ash coal are about 6%. Under the gasification temperature ranging from 830 to 900{sup o}C and from 900 to 920{sup o}C, the apparent reaction order of Yangquan high-ash coal with respect to the unreacted carbon fraction approximates to 2.3 and 1/3 for the non-catalyst case, respectively. Also, the different values of apparent reaction order in the two temperature ranges are presented for the case with 3% solid alkali catalyst loaded. At the low temperature ranging from 830 to 860{sup o}C, the apparent reaction order of catalytic gasification is 1 since enough active carbon sites on the coal surface are formed during the catalytic gasification by solid alkali. But at the high temperature ranging from 860 to 920{sup o}C, the sodium carbonate produced by the reaction of solid alkali with carbon dioxide can be easily fused, transferred and re-distributed, which affects the gasification reaction rate, and the apparent reaction order of catalytic gasification is reduced to 1.3. 10 refs., 9 figs., 4 tab s.

  16. High temperature turbine engine structure

    Energy Technology Data Exchange (ETDEWEB)

    Carruthers, W.D.; Boyd, G.L.

    1993-07-20

    A hybrid ceramic/metallic gas turbine is described comprising; a housing defining an inlet, an outlet, and a flow path communicating the inlet with the outlet for conveying a flow of fluid through the housing, a rotor member journaled by the housing in the flow path, the rotor member including a compressor rotor portion rotatively inducting ambient air via the inlet and delivering this air pressurized to the flow path downstream of the compressor rotor, a combustor disposed in the flow path downstream of the compressor receiving the pressurized air along with a supply of fuel to maintain combustion providing a flow of high temperature pressurized combustion products in the flow path downstream thereof, the rotor member including a turbine rotor portion disposed in the flow path downstream of the combustor and rotatively expanding the combustion products toward ambient for flow from the turbine engine via the outlet, the turbine rotor portion providing shaft power driving the compressor rotor portion and an output shaft portion of the rotor member, a disk-like metallic housing portion journaling the rotor member to define a rotational axis therefore, and a disk-like annular ceramic turbine shroud member bounding the flow path downstream of the combustor and circumscribing the turbine rotor portion to define a running clearance therewith, the disk-like ceramic turbine shroud member having a reference axis coaxial with the rotational axis and being spaced axially from the metallic housing portion in mutually parallel concentric relation therewith and a plurality of spacers disposed between ceramic disk-like shroud member and the metallic disk-like housing portion and circumferentially spaced apart, each of the spacers having a first and second end portion having an end surface adjacent the shroud member and the housing portion respectively, the end surfaces having a cylindrical curvature extending transversely relative to the shroud member and the housing portion.

  17. RESEARCH ON THE INFLUENCE OF TEMPERATURE ON THE ACTIVATION OF SELECTED POROUS MNO2 BEDS

    OpenAIRE

    Iwona Skoczko; Agnieszka Kisło

    2016-01-01

    Rising demands concerning water treatment and conservation make it necessary to search for more effective as well as cheap and ecologically safe solutions. During the filtration process quartz sand is replaced by filter materials which also have a strong effect on account of reactions taking place on a bed’s surface. Today’s technologies for groundwater and seepage water treatment in rapid filters make use of oxidation beds. They are able to effectively remove manganese (II) and iron (II) com...

  18. Dynamic model development and validation for a nitrifying moving bed biofilter: Effect of temperature and influent load on the performance

    DEFF Research Database (Denmark)

    Sin, Gürkan; Weijma, Jan; Spanjers, Henri

    2008-01-01

    A mathematical model with adequate complexity integrating hydraulics, biofilm and microbial conversion processes is successfully developed for a continuously moving bed biofilter performing tertiary nitrification. The model was calibrated and validated using data from Nether Stowey pilot plant...... on the ammonium removal efficiency, doubling nitrification capacity every 5 degrees C increase. However, at temperatures higher than 20 degrees C, the biofilm thickness starts to decrease due to increased decay rate. The influent nitrogen load was also found to be influential on the filter performance, while...... the hydraulic loading had relatively negligible impact. Overall, the calibrated model can now reliably be used for design and process optimization purposes....

  19. Women's experience of hospitalized bed rest during high-risk pregnancy.

    Science.gov (United States)

    Rubarth, Lori Baas; Schoening, Anne M; Cosimano, Amy; Sandhurst, Holly

    2012-01-01

    To describe the lived experience of the hospitalized pregnant woman on bed rest. A qualitative, phenomenological design. Three high-risk antepartum units in the midwestern United States. A self-selected, convenience sample of 11 high-risk pregnant women. Phenomenological study using thematic analysis of completed handwritten journals and/or online blogs. Women described the battles that they fought each day for the lives of their unborn children. Using an imagery of war, three categories emerged: (a) the war within, (b) fighting each battle, and (c) bringing in reinforcements. Women experience many different emotions and stressors during restricted bed rest. A nurse's understanding of this experience is essential to provide adequate care and coping strategies for women at this time. © 2012 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses.

  20. Gas distributor for fluidized bed coal gasifier

    Science.gov (United States)

    Worley, Arthur C.; Zboray, James A.

    1980-01-01

    A gas distributor for distributing high temperature reaction gases to a fluidized bed of coal particles in a coal gasification process. The distributor includes a pipe with a refractory reinforced lining and a plurality of openings in the lining through which gas is fed into the bed. These feed openings have an expanding tapered shape in the downstream or exhaust direction which aids in reducing the velocity of the gas jets as they enter the bed.

  1. Design and development of fluidized bed reactor system for production of trichlorosilane as a precursor for high purity silicon

    International Nuclear Information System (INIS)

    Kumar, Rajesh; Mohan, Sadhana; Bhanja, K.; Nayak, S.; Bhattacharya, S.K.

    2009-01-01

    Trichlorosilane is widely used as precursor material for production of high purity silicon. It is mainly produced by reaction of metallurgical grade silicon with anhydrous HCl gas in a fluidized bed reactor. To develop this process on commercial scale a pilot size fluidized bed reactor system was designed and developed and successfully operated. This paper discusses the critical issues related to these activities. (author)

  2. High School Students’ Use of Sunscreen and Tanning Beds

    Centers for Disease Control (CDC) Podcasts

    2014-08-20

    This podcast is an interview with Corey Basch, EdD, MPH, assistant professor in the Department of Public Health at William Paterson University. Dr. Basch discusses her study on high school students’ use of sunscreen and tanning beds between 2001 and 2011.  Created: 8/20/2014 by Preventing Chronic Disease (PCD), National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 8/20/2014.

  3. High temperature water chemistry monitoring

    International Nuclear Information System (INIS)

    Aaltonen, P.

    1992-01-01

    Almost all corrosion phenomena in nuclear power plants can be prevented or at least damped by water chemistry control or by the change of water chemistry control or by the change of water chemistry. Successful water chemistry control needs regular and continuous monitoring of such water chemistry parameters like dissolved oxygen content, pH, conductivity and impurity contents. Conventionally the monitoring is carried out at low pressures and temperatures, which method, however, has some shortcomings. Recently electrodes have been developed which enables the direct monitoring at operating pressures and temperatures. (author). 2 refs, 5 figs

  4. Effect of Bed Temperature on the Laser Energy Required to Sinter Copper Nanoparticles

    Science.gov (United States)

    Roy, N. K.; Dibua, O. G.; Cullinan, M. A.

    2018-03-01

    Copper nanoparticles (NPs), due to their high electrical conductivity, low cost, and easy availability, provide an excellent alternative to other metal NPs such as gold, silver, and aluminum in applications ranging from direct printing of conductive patterns on metal and flexible substrates for printed electronics applications to making three-dimensional freeform structures for interconnect fabrication for chip-packaging applications. Lack of research on identification of optimum sintering parameters such as fluence/irradiance requirements for sintering of Cu NPs serves as the primary motivation for this study. This article focuses on the identification of a good sintering irradiance window for Cu NPs on an aluminum substrate using a continuous wave (CW) laser. The study also includes the comparison of CW laser sintering irradiance windows obtained with substrates at different initial temperatures. The irradiance requirements for sintering of Cu NPs with the substrate at 150-200°C were found to be 5-17 times smaller than the irradiance requirements for sintering with the substrate at room temperature. These findings were also compared against the results obtained with a nanosecond (ns) laser and a femtosecond (fs) laser.

  5. High temperature soldering of graphite

    International Nuclear Information System (INIS)

    Anikin, L.T.; Kravetskij, G.A.; Dergunova, V.S.

    1977-01-01

    The effect is studied of the brazing temperature on the strength of the brazed joint of graphite materials. In one case, iron and nickel are used as solder, and in another, molybdenum. The contact heating of the iron and nickel with the graphite has been studied in the temperature range of 1400-2400 ged C, and molybdenum, 2200-2600 deg C. The quality of the joints has been judged by the tensile strength at temperatures of 2500-2800 deg C and by the microstructure. An investigation into the kinetics of carbon dissolution in molten iron has shown that the failure of the graphite in contact with the iron melt is due to the incorporation of iron atoms in the interbase planes. The strength of a joint formed with the participation of the vapour-gas phase is 2.5 times higher than that of a joint obtained by graphite recrystallization through the carbon-containing metal melt. The critical temperatures are determined of graphite brazing with nickel, iron, and molybdenum interlayers, which sharply increase the strength of the brazed joint as a result of the formation of a vapour-gas phase and deposition of fine-crystal carbon

  6. Resonance integral calculations for high temperature reactors

    International Nuclear Information System (INIS)

    Blake, J.P.H.

    1960-02-01

    Methods of calculation of resonance integrals of finite dilution and temperature are given for both, homogeneous and heterogeneous geometries, together with results obtained from these methods as applied to the design of high temperature reactors. (author)

  7. Hot nuclei: high temperatures, high angular momenta

    International Nuclear Information System (INIS)

    Guerreau, D.

    1991-01-01

    A review is made of the present status concerning the production of hot nuclei above 5 MeV temperature, concentrating mainly on the possible experimental evidences for the attainment of a critical temperature, on the existence of dynamical limitations to the energy deposition and on the experimental signatures for the formation of hot spinning nuclei. The data strongly suggest a nuclear disassembly in collisions involving very heavy ions at moderate incident velocities. Furthermore, hot nuclei seem to be quite stable against rotation on a short time scale. (author) 26 refs.; 12 figs

  8. Deep Trek High Temperature Electronics Project

    Energy Technology Data Exchange (ETDEWEB)

    Bruce Ohme

    2007-07-31

    This report summarizes technical progress achieved during the cooperative research agreement between Honeywell and U.S. Department of Energy to develop high-temperature electronics. Objects of this development included Silicon-on-Insulator (SOI) wafer process development for high temperature, supporting design tools and libraries, and high temperature integrated circuit component development including FPGA, EEPROM, high-resolution A-to-D converter, and a precision amplifier.

  9. In Developping a Bench-Scale Circulating Fluidized Bed Combustor to Burn High Ash Brazilian Coal-Dolomites Mixtures

    Science.gov (United States)

    Ramírez Behainne, Jhon Jairo; Hory, Rogério Ishikawa; Goldstein, Leonardo; Bernárdez Pécora, Araí Augusta

    This work considers some of the questions in burning high ash Brazilian coal-dolomite mixtures in a bench-scale circulating fluidized bed combustor (CFBC). Experimental tests were performed with the CE4500 coal from Santa Catarina State, in southern Brazil, with a Sauter mean diameter d p =43 μm. The coal particles were mixed with dolomite particles of d p = 111 μm and this fuel mixture was fed into the circulating fluidized reactor, previously loaded with quartz sand particles of d p =353 μm. This inert material was previously heated by the combustion of liquefied petroleum gas up to the ignition temperature of the fuel mixture. The CFBC unit has a 100mm internal diameter riser, 4.0m high, as well as a 62.8mm internal diameter downcomer. The loop has a cyclone, a sampling valve to collect particles and a 62.8mm internal diameter L-valve to recirculate the particles in the loop. A screw feeder with a rotation control system was used to feed the fuel mixture to the reactor. The operational conditions were monitored by pressure taps and thermocouples installed along the loop. A data acquisition system showed the main operational conditions to control. Experimental tests performed put in evidence the problems found during bed operation, with special attention to the solids feed device, to the L-valve operation, to particle size, solids inventory, fluidized gas velocity, fuel mixture and recirculated solids feeding positions.

  10. Modeling of laser radiation transport in powder beds with high-dispersive metal particles

    Energy Technology Data Exchange (ETDEWEB)

    Kharanzhevskiy, Evgeny, E-mail: eh@udsu.ru [Udmurt State University, 426034 Universitetskaya St., 1, Izhevsk (Russian Federation); Kostenkov, Sergey [Udmurt State University, 426034 Universitetskaya St., 1, Izhevsk (Russian Federation)

    2014-02-15

    Highlights: ► Transport of laser energy in dispersive powder beds was numerically simulated. ► The results of simulating are compared with physicals experiments. ► We established the dependence of the extinction coefficient from powder properties. ► A confirmation of a geometric optic approach for monodisperse powders was proposed. -- Abstract: Two-dimensional transfer of laser radiation in a high-dispersive powder heterogeneous media is numerically calculated. The size of particles is comparable with the wave length of laser radiation so the model takes into account all known physical effects that are occurred on the vacuum–metal surface interface. It is shown that in case of small particles size both morphology of powder particles and porosity of beds influence on absorptance by the solid phase and laser radiation penetrate deep into the area of geometric shadow. Intensity of laser radiation may be described as a function corresponded to the Beer–Lambert–Bouguer law.

  11. Modeling of laser radiation transport in powder beds with high-dispersive metal particles

    International Nuclear Information System (INIS)

    Kharanzhevskiy, Evgeny; Kostenkov, Sergey

    2014-01-01

    Highlights: ► Transport of laser energy in dispersive powder beds was numerically simulated. ► The results of simulating are compared with physicals experiments. ► We established the dependence of the extinction coefficient from powder properties. ► A confirmation of a geometric optic approach for monodisperse powders was proposed. -- Abstract: Two-dimensional transfer of laser radiation in a high-dispersive powder heterogeneous media is numerically calculated. The size of particles is comparable with the wave length of laser radiation so the model takes into account all known physical effects that are occurred on the vacuum–metal surface interface. It is shown that in case of small particles size both morphology of powder particles and porosity of beds influence on absorptance by the solid phase and laser radiation penetrate deep into the area of geometric shadow. Intensity of laser radiation may be described as a function corresponded to the Beer–Lambert–Bouguer law

  12. High temperature alloys and ceramic heat exchanger

    International Nuclear Information System (INIS)

    Okamoto, Masaharu

    1984-04-01

    From the standpoint of energy saving, the future operating temperatures of process heat and gas turbine plants will become higher. For this purpose, ceramics is the most promissing candidate material in strength for application to high-temperature heat exchangers. This report deals with a servey of characteristics of several high-temperature metallic materials and ceramics as temperature-resistant materials; including a servey of the state-of-the-art of ceramic heat exchanger technologies developed outside of Japan, and a study of their application to the intermediate heat exchanger of VHTR (a very-high-temperature gas-cooled reactor). (author)

  13. High-temperature peridotites - lithospheric or asthenospheric?

    International Nuclear Information System (INIS)

    Hops, J.J.; Gurney, J.J.

    1990-01-01

    High-temperature peridotites by definition yield equilibration temperatures greater than 1100 degrees C. On the basis of temperature and pressure calculations, these high-temperature peridotites are amongst the deepest samples entrained by kimberlites on route to the surface. Conflicting models proposing either a lithospheric or asthenospheric origin for the high-temperature peridotites have been suggested. A detailed study of these xenoliths from a single locality, the Jagersfontein kimberlite in the Orange Free State, has been completed as a means of resolving this controversy. 10 refs., 2 figs

  14. Impact of temperature on ammonium and nitrite removal rates in RAS moving bed biofilters

    DEFF Research Database (Denmark)

    Kinyage, John Peter Hewa; Pedersen, Lars-Flemming

    2016-01-01

    The impact of temperature on bacterial processes is well known; however temperature related data on nitrification rates in aquaculture systems are fragmented and compiled from different studies. We sought to determine ammonium and nitrite removal kinetics over a temperature range from 6 to 36 °C...

  15. High temperature phase equilibria and phase diagrams

    CERN Document Server

    Kuo, Chu-Kun; Yan, Dong-Sheng

    2013-01-01

    High temperature phase equilibria studies play an increasingly important role in materials science and engineering. It is especially significant in the research into the properties of the material and the ways in which they can be improved. This is achieved by observing equilibrium and by examining the phase relationships at high temperature. The study of high temperature phase diagrams of nonmetallic systems began in the early 1900s when silica and mineral systems containing silica were focussed upon. Since then technical ceramics emerged and more emphasis has been placed on high temperature

  16. Development of High Temperature Solid Lubricant Coatings

    National Research Council Canada - National Science Library

    Bhattacharya, Rabi

    1999-01-01

    ... environment. To test this approach, UES and Cleveland State University have conducted experiments to form cesium oxythiotungstate, a high temperature lubricant, on Inconel 718 surface from composite coatings...

  17. Advances in high temperature chemistry 1

    CERN Document Server

    Eyring, Leroy

    2013-01-01

    Advances in High Temperature Chemistry, Volume 1 describes the complexities and special and changing characteristics of high temperature chemistry. After providing a brief definition of high temperature chemistry, this nine-chapter book goes on describing the experiments and calculations of diatomic transition metal molecules, as well as the advances in applied wave mechanics that may contribute to an understanding of the bonding, structure, and spectra of the molecules of high temperature interest. The next chapter provides a summary of gaseous ternary compounds of the alkali metals used in

  18. High temperature mechanical properties of iron aluminides

    International Nuclear Information System (INIS)

    Morris, D. G.; Munoz-Morris, M. A.

    2001-01-01

    Considerable attention has been given to the iron aluminide family of intermetallics over the past years since they offer considerable potential as engineering materials for intermediate to high temperature applications, particularly in cases where extreme oxidation or corrosion resistance is required. Despite efforts at alloy development, however, high temperature strength remains low and creep resistance poor. Reasons for the poor high-temperature strength of iron aluminides will be discussed, based on the ordered crystal structure, the dislocation structure found in the materials, and the mechanisms of dislocation pinning operating. Alternative ways of improving high temperature strength by microstructural modification and the inclusion of second phase particles will also be considered. (Author)

  19. Investigations into High Temperature Components and Packaging

    Energy Technology Data Exchange (ETDEWEB)

    Marlino, L.D.; Seiber, L.E.; Scudiere, M.B.; M.S. Chinthavali, M.S.; McCluskey, F.P.

    2007-12-31

    The purpose of this report is to document the work that was performed at the Oak Ridge National Laboratory (ORNL) in support of the development of high temperature power electronics and components with monies remaining from the Semikron High Temperature Inverter Project managed by the National Energy Technology Laboratory (NETL). High temperature electronic components are needed to allow inverters to operate in more extreme operating conditions as required in advanced traction drive applications. The trend to try to eliminate secondary cooling loops and utilize the internal combustion (IC) cooling system, which operates with approximately 105 C water/ethylene glycol coolant at the output of the radiator, is necessary to further reduce vehicle costs and weight. The activity documented in this report includes development and testing of high temperature components, activities in support of high temperature testing, an assessment of several component packaging methods, and how elevated operating temperatures would impact their reliability. This report is organized with testing of new high temperature capacitors in Section 2 and testing of new 150 C junction temperature trench insulated gate bipolar transistor (IGBTs) in Section 3. Section 4 addresses some operational OPAL-GT information, which was necessary for developing module level tests. Section 5 summarizes calibration of equipment needed for the high temperature testing. Section 6 details some additional work that was funded on silicon carbide (SiC) device testing for high temperature use, and Section 7 is the complete text of a report funded from this effort summarizing packaging methods and their reliability issues for use in high temperature power electronics. Components were tested to evaluate the performance characteristics of the component at different operating temperatures. The temperature of the component is determined by the ambient temperature (i.e., temperature surrounding the device) plus the

  20. High temperature humidity sensing materials

    International Nuclear Information System (INIS)

    Tsai, P.P.; Tanase, S.; Greenblatt, M.

    1989-01-01

    This paper reports on new proton conducting materials prepared and characterized for potential applications in humidity sensing at temperatures higher than 100 degrees C by complex impedance or galvanic cell type techniques. Calcium metaphosphate, β-Ca(PO 3 ) 2 as a galvanic cell type sensor material yields reproducible signals in the range from 5 to 200 mm Hg water vapor pressure at 578 degrees C, with short response time (∼ 30 sec). Polycrystalline samples of α-Zr(HPO 4 ) 2 and KMo 3 P 5.8 Si 2 O 25 , and the gel converted ceramic, 0.10Li 2 O-0.25P 2 O 5 -0.65SiO 2 as impedance sensor materials show decreases in impedance with increasing humidity in the range from 9 mm Hg to 1 atm water vapor pressure at 179 degrees C

  1. Design of Jet lower hybrid current drive generator and operation of high power test bed

    International Nuclear Information System (INIS)

    Dobbing, J.A.; Bosia, G.; Brandon, M.; Gammelin, M.; Gormezano, C.; Jacquinot, J.; Jessop, G.; Lennholm, M.; Pain, M.; Sibley, A.

    1989-01-01

    The JET Lower Hybrid Current Drive (LHCD) generator consists of 24 klystrons each rated for 650 KW operating at 3.7 GHz, giving a nominal generator power of 15.6 MW for 10 seconds or 12 MW for 20 seconds. This power will be transmitted through 24 waveguides to a phased array launcher on one of the main ports of the JET machine. In addition, two klystrons are currently being operated on a high power test bed to establish reliable operation of the generators components and test high power microwave components prior to their installation

  2. Spin Hall magnetoresistance at high temperatures

    International Nuclear Information System (INIS)

    Uchida, Ken-ichi; Qiu, Zhiyong; Kikkawa, Takashi; Iguchi, Ryo; Saitoh, Eiji

    2015-01-01

    The temperature dependence of spin Hall magnetoresistance (SMR) in Pt/Y 3 Fe 5 O 12 (YIG) bilayer films has been investigated in a high temperature range from room temperature to near the Curie temperature of YIG. The experimental results show that the magnitude of the magnetoresistance ratio induced by the SMR monotonically decreases with increasing the temperature and almost disappears near the Curie temperature. We found that, near the Curie temperature, the temperature dependence of the SMR in the Pt/YIG film is steeper than that of a magnetization curve of the YIG; the critical exponent of the magnetoresistance ratio is estimated to be 0.9. This critical behavior of the SMR is attributed mainly to the temperature dependence of the spin-mixing conductance at the Pt/YIG interface

  3. Nuclear fuels for very high temperature applications

    International Nuclear Information System (INIS)

    Lundberg, L.B.; Hobbins, R.R.

    1992-01-01

    The success of the development of nuclear thermal propulsion devices and thermionic space nuclear power generation systems depends on the successful utilization of nuclear fuel materials at temperatures in the range 2000 to 3500 K. Problems associated with the utilization of uranium bearing fuel materials at these very high temperatures while maintaining them in the solid state for the required operating times are addressed. The critical issues addressed include evaporation, melting, reactor neutron spectrum, high temperature chemical stability, fabrication, fission induced swelling, fission product release, high temperature creep, thermal shock resistance, and fuel density, both mass and fissile atom. Candidate fuel materials for this temperature range are based on UO 2 or uranium carbides. Evaporation suppression, such as a sealed cladding, is required for either fuel base. Nuclear performance data needed for design are sparse for all candidate fuel forms in this temperature range, especially at the higher temperatures

  4. Corrosion Resistant Coatings for High Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Besman, T.M.; Cooley, K.M.; Haynes, J.A.; Lee, W.Y.; Vaubert, V.M.

    1998-12-01

    Efforts to increase efficiency of energy conversion devices have required their operation at ever higher temperatures. This will force the substitution of higher-temperature structural ceramics for lower temperature materials, largely metals. Yet, many of these ceramics will require protection from high temperature corrosion caused by combustion gases, atmospheric contaminants, or the operating medium. This paper discusses examples of the initial development of such coatings and materials for potential application in combustion, aluminum smelting, and other harsh environments.

  5. High Temperature Calcination - MACT Upgrade Equipment Pilot Plant Test

    Energy Technology Data Exchange (ETDEWEB)

    Richard D. Boardman; B. H. O& #39; Brien; N. R. Soelberg; S. O. Bates; R. A. Wood; C. St. Michel

    2004-02-01

    About one million gallons of acidic, hazardous, and radioactive sodium-bearing waste are stored in stainless steel tanks at the Idaho Nuclear Technology and Engineering Center (INTEC), which is a major operating facility of the Idaho National Engineering and Environmental Laboratory. Calcination at high-temperature conditions (600 C, with alumina nitrate and calcium nitrate chemical addition to the feed) is one of four options currently being considered by the Department of Energy for treatment of the remaining tank wastes. If calcination is selected for future processing of the sodium-bearing waste, it will be necessary to install new off-gas control equipment in the New Waste Calcining Facility (NWCF) to comply with the Maximum Achievable Control Technology (MACT) standards for hazardous waste combustors and incinerators. This will require, as a minimum, installing a carbon bed to reduce mercury emissions from their current level of up to 7,500 to <45 {micro}g/dscm, and a staged combustor to reduce unburned kerosene fuel in the off-gas discharge to <100 ppm CO and <10 ppm hydrocarbons. The staged combustor will also reduce NOx concentrations of about 35,000 ppm by 90-95%. A pilot-plant calcination test was completed in a newly constructed 15-cm diameter calciner vessel. The pilot-plant facility was equipped with a prototype MACT off-gas control system, including a highly efficient cyclone separator and off-gas quench/venturi scrubber for particulate removal, a staged combustor for unburned hydrocarbon and NOx destruction, and a packed activated carbon bed for mercury removal and residual chloride capture. Pilot-plant testing was performed during a 50-hour system operability test January 14-16, followed by a 100-hour high-temperature calcination pilot-plant calcination run January 19-23. Two flowsheet blends were tested: a 50-hour test with an aluminum-to-alkali metal molar ratio (AAR) of 2.25, and a 50-hour test with an AAR of 1.75. Results of the testing

  6. Aspects of high temperature superconductivity

    International Nuclear Information System (INIS)

    Deutscher, G.

    1989-01-01

    We present some remarks on special features that distinguish the phenomenology of the new high T c oxides from that of the conventional superconductors. They include a measurable width of the critical region and a high sensitivity to crystallographic defects. A consistent Landau Ginsburg interpretation is possible, with a short coherence length <15 A and a penetration depth <900 A. The latter is somewhat smaller than the currently accepted value, and implies a broad band scheme

  7. Borehole Stability in High-Temperature Formations

    Science.gov (United States)

    Yan, Chuanliang; Deng, Jingen; Yu, Baohua; Li, Wenliang; Chen, Zijian; Hu, Lianbo; Li, Yang

    2014-11-01

    In oil and gas drilling or geothermal well drilling, the temperature difference between the drilling fluid and formation will lead to an apparent temperature change around the borehole, which will influence the stress state around the borehole and tend to cause borehole instability in high geothermal gradient formations. The thermal effect is usually not considered as a factor in most of the conventional borehole stability models. In this research, in order to solve the borehole instability in high-temperature formations, a calculation model of the temperature field around the borehole during drilling is established. The effects of drilling fluid circulation, drilling fluid density, and mud displacement on the temperature field are analyzed. Besides these effects, the effect of temperature change on the stress around the borehole is analyzed based on thermoelasticity theory. In addition, the relationships between temperature and strength of four types of rocks are respectively established based on experimental results, and thermal expansion coefficients are also tested. On this basis, a borehole stability model is established considering thermal effects and the effect of temperature change on borehole stability is also analyzed. The results show that the fracture pressure and collapse pressure will both increase as the temperature of borehole rises, and vice versa. The fracture pressure is more sensitive to temperature. Temperature has different effects on collapse pressures due to different lithological characters; however, the variation of fracture pressure is unrelated to lithology. The research results can provide a reference for the design of drilling fluid density in high-temperature wells.

  8. Scale hierarchy in high-temperature QCD

    CERN Document Server

    Akerlund, Oscar

    2013-01-01

    Because of asymptotic freedom, QCD becomes weakly interacting at high temperature: this is the reason for the transition to a deconfined phase in Yang-Mills theory at temperature $T_c$. At high temperature $T \\gg T_c$, the smallness of the running coupling $g$ induces a hierachy betwen the "hard", "soft" and "ultrasoft" energy scales $T$, $g T$ and $g^2 T$. This hierarchy allows for a very successful effective treatment where the "hard" and the "soft" modes are successively integrated out. However, it is not clear how high a temperature is necessary to achieve such a scale hierarchy. By numerical simulations, we show that the required temperatures are extremely high. Thus, the quantitative success of the effective theory down to temperatures of a few $T_c$ appears surprising a posteriori.

  9. High temperature oxidation behavior of ODS steels

    Science.gov (United States)

    Kaito, T.; Narita, T.; Ukai, S.; Matsuda, Y.

    2004-08-01

    Oxide dispersion strengthened (ODS) steels are being developing for application as advanced fast reactor cladding and fusion blanket materials, in order to allow increased operation temperature. Oxidation testing of ODS steel was conducted under a controlled dry air atmosphere to evaluate the high temperature oxidation behavior. This showed that 9Cr-ODS martensitic steels and 12Cr-ODS ferritic steels have superior high temperature oxidation resistance compared to 11 mass% Cr PNC-FMS and 17 mass% Cr ferritic stainless steel. This high temperature resistance is attributed to earlier formation of the protective α-Cr 2O 3 on the outer surface of ODS steels.

  10. Quantum electrodynamics at high temperature. 2

    International Nuclear Information System (INIS)

    Alvarez-Estrada, R.F.

    1988-01-01

    The photon sector of QED in d = 3 spatial dimensions is analyzed at high temperature thereby generalizing nontrivially a previous study for d = 1. The imaginary time formalism and an improved renormalized perturbation theory which incorporates second order Debye screening are used. General results are presented for the leading high temperature contributions to all renormalized connected photon Green's functions for fixed external momenta (much smaller than the temperature) to all orders in the improved perturbation theory. Those leading contributions are ultraviolet finite, infrared convergent and gauge invariant, and display an interesting form of dimensional reduction at high temperature. A new path integral representations is given for the high temperature partition function with an external photon source, which is shown to generate all leading high temperature Green's functions mentioned above, and, so, it displays neatly the kind of dimensional reduction which makes QED to become simpler at high temperature. This limiting partition function corresponds to an imaginary time dependent electron positron field interacting with an electromagnetic field at zero imaginary time, and it depends on the renormalized electron mass and electric charge, the second order contribution to the usual renormalization constant Z 3 and a new mass term, which is associated to the photon field with vanishing Lorentz index. The new mass term corresponds to a finite number of diagrams in the high temperature improved perturbation theory and carriers ultraviolet divergences which are compensated for by other contributions (so that the leading high temperature Green's functions referred to above are ultraviolet finite). The dominant high temperature contributions to the renormalized thermodynamic potential to all perturbative orders: i) are given in terms of the above leading high-temperature contributions to the photon Green's functions (except for a few diagrams of low order in the

  11. Theory of high temperature superconductivity

    International Nuclear Information System (INIS)

    Srivastava, C.M.

    1989-01-01

    This paper develops a semi-empirical electronic band structure for a high T c superconductor like YBa 2 Cu 3 O 6 - δ . The author accounts for the electrical transport properties on the model based on the correlated electron transfer arising from the electron-phonon interaction. The momentum pairing leading to the superconducting phase amongst the mobile charge carriers is shown

  12. The influence of channel bed disturbance on benthic Chlorophyll a: A high resolution perspective

    Science.gov (United States)

    Katz, Scott B.; Segura, Catalina; Warren, Dana R.

    2018-03-01

    This study explores how spatial dynamics and frequency of bed mobility events in a headwater stream affect the spatial and temporal variability in stream benthic algal abundance and ultimately the resilience of benthic algae to stream scouring events of different magnitudes. We characterized spatial variability in sediment transport for nine separate flow events (0.1-1.7 of bankfull flow), coupling high resolution (level categories defined based on the relative movement of the median grain size on 14 occasions. However, low disturbance locations were not always associated with higher Chl-a. The algal Chl-a biomass at any given time was a function of the stage of algal recovery following a high flow event and the magnitude of the disturbance itself - impacting algal loss during the event. Resistance of the algal communities to bed disturbance and resilience to recovery following a flow event varied spatially. Areas with low shear stress were less susceptible to scour during moderate disturbance events but were slower to recover when scour occurred. In contrast, high shear stress areas responded rapidly to flood events with rapid declines, but also recovered more quickly and appeared to have high potential for maximum accrual within our study reach. Ultimately, timing along with the inverse relationship between resiliency and disturbance frequency highlights the complexity of these processes and the importance of studying the interactions between geomorphic and ecological processes with high resolution across spatial and temporal scales.

  13. High temperature reactor development in the Netherlands

    International Nuclear Information System (INIS)

    Heek, A.I. van

    1996-01-01

    This year, some clear design choices have been made in the WHITE Reactor development programme. The activities will be concentrated at the development of a small size pebble bed HTR for combined heat and power production with a closed cycle gas turbine. Objective of the development is threefold: 1. restoring social support; 2. establishing commercial viability after market introduction; and 3. making the market introduction itself feasible, i.e. limited development and first-of-a-kind costs. This design is based on the peu-a-peu design of KFA Juelich and will be optimized. The computer codes necessary for this are being prepared for this work. The dynamic neutronics code PANTHER is being coupled to the thermal hydraulics code THERMIX-DIREKT. For this reactor type, fuel temperatures are maximal in the scenario of depressurization with recriticality. Even for this scenario, fuel temperatures of the 20MWth PAP-GT do not exceed 1300 deg. C, so there should be room for upscaling for economic reasons. On the other hand, it would be convenient to fuel the reactor batchwise instead of continuously, and the use of thorium could be required. These two features may lead to a larger temperature margin. The optimal design must unite these features in the best acceptable way. To gain expertise in calculations on gas cooled graphite moderate reactors, benchmark calculations are being performed in parallel with international partners. Parallel to this, special expertise is being built up on HTR fuel and HTR reactor vessels. (author). 3 refs

  14. High temperature resistant cermet and ceramic compositions

    Science.gov (United States)

    Phillips, W. M. (Inventor)

    1978-01-01

    Cermet compositions having high temperature oxidation resistance, high hardness and high abrasion and wear resistance, and particularly adapted for production of high temperature resistant cermet insulator bodies are presented. The compositions are comprised of a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Also disclosed are novel ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride.

  15. Fluid-bed process for SYNROC production

    International Nuclear Information System (INIS)

    Ackerman, F.J.; Grens, J.Z.; Ryerson, F.J.; Hoenig, C.L.; Bazan, F.; Peters, P.E.; Smith, R.; Campbell, J.H.

    1983-01-01

    SYNROC is a titanate-based ceramic waste developed for the immobilization of high-level nuclear reactor waste. Lawrence Livermore National Laboratory (LLNL) has investigated a fluid-bed technique for the large-scale production of SYNROC precursor powders. Making SYNROC in a fluid bed permits slurry drying, calcination and reduction-oxidation reactions to be carried out in a single unit. We present the results of SYNROC fluid-bed studies from two fluid-bed units 10 cm in diameter: an internally heated fluid-bed unit developed by Exxon Idaho and an externally heated unit constructed at LLNL. Bed operation over a range of temperatures, feed rates, fluidizing rates, and redox conditions indicate that SYNROC powders of a high density and a uniform particle size can be produced. These powders facilitate the densification step and yield dense ceramics (greater than 95% theoretical density) with well-developed phases and low leaching rates

  16. High Temperature Electrostrictive Ceramics, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — TRS Technologies proposes to develop high temperature electrostrictors from bismuth-based ferroelectrics. These materials will exhibit high strain and low loss in...

  17. High temperature solar selective coatings

    Science.gov (United States)

    Kennedy, Cheryl E

    2014-11-25

    Improved solar collectors (40) comprising glass tubing (42) attached to bellows (44) by airtight seals (56) enclose solar absorber tubes (50) inside an annular evacuated space (54. The exterior surfaces of the solar absorber tubes (50) are coated with improved solar selective coatings {48} which provide higher absorbance, lower emittance and resistance to atmospheric oxidation at elevated temperatures. The coatings are multilayered structures comprising solar absorbent layers (26) applied to the meta surface of the absorber tubes (50), typically stainless steel, topped with antireflective Savers (28) comprising at least two layers 30, 32) of refractory metal or metalloid oxides (such as titania and silica) with substantially differing indices of refraction in adjacent layers. Optionally, at least one layer of a noble metal such as platinum can be included between some of the layers. The absorbent layers cars include cermet materials comprising particles of metal compounds is a matrix, which can contain oxides of refractory metals or metalloids such as silicon. Reflective layers within the coating layers can comprise refractory metal silicides and related compounds characterized by the formulas TiSi. Ti.sub.3SiC.sub.2, TiAlSi, TiAN and similar compounds for Zr and Hf. The titania can be characterized by the formulas TiO.sub.2, Ti.sub.3O.sub.5. TiOx or TiO.sub.xN.sub.1-x with x 0 to 1. The silica can be at least one of SiO.sub.2, SiO.sub.2x or SiO.sub.2xN.sub.1-x with x=0 to 1.

  18. Development of a low-temperature two-stage fluidized bed incinerator for controlling heavy-metal emission in flue gases

    International Nuclear Information System (INIS)

    Peng, Tzu-Huan; Lin, Chiou-Liang; Wey, Ming-Yen

    2014-01-01

    This study develops a low-temperature two-stage fluidized bed system for treating municipal solid waste. This new system can decrease the emission of heavy metals, has low construction costs, and can save energy owing to its lower operating temperature. To confirm the treatment efficiency of this system, the combustion efficiency and heavy-metal emission were determined. An artificial waste containing heavy metals (chromium, lead, and cadmium) was used in this study. The tested parameters included first-stage temperature and system gas velocity. Results obtained using a thermogravimetric analyzer with a differential scanning calorimeter indicated that the first-stage temperature should be controlled to at least 400 °C. Although, a large amount of carbon monoxide was emitted after the first stage, it was efficiently consumed in the second. Loss of the ignition values of ash residues were between 0.005% and 0.166%, and they exhibited a negative correlation with temperature and gas velocity. Furthermore, the emission concentration of heavy metals in the two-stage system was lower than that of the traditional one-stage fluidized bed system. The heavy-metal emissions can be decreased by between 16% and 82% using the low-temperature operating process, silica sand adsorption, and the filtration of the secondary stage. -- Graphical abstract: Heavy-metal emission concentrations in flue gases under different temperatures and gas velocities (dashed line: average of the heavy-metal emission in flue gases in the one-stage fluidized-bed incinerator). Highlights: • Low temperature two-stage system is developed to control heavy metal. • The different first-stage temperatures affect the combustion efficiency. • Surplus CO was destroyed efficiently by the secondary fluidized bed combustor. • Metal emission in two-stage system is lower than in the traditional system. • Temperature, bed adsorption, and filtration are the main control mechanisms

  19. Recrystallization of high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kouzoudis, Dimitris [Iowa State Univ., Ames, IA (United States)

    1996-05-09

    Currently one of the most widely used high Tc superconductors is the Bi-based compounds Bi2Sr2CaCu2Oz and Bi2Sr2Ca2Cu3Oz (known as BSCCO 2212 and 2223 compounds) with Tc values of about 85 K and 110 K respectively. Lengths of high performance conductors ranging from 100 to 1000 m long are routinely fabricated and some test magnets have been wound. An additional difficulty here is that although Bi-2212 and Bi-2223 phases exist over a wide range of stoichiometries, neither has been prepared in phase-pure form. So far the most successful method of constructing reliable and robust wires or tapes is the so called powder-in-tube (PIT) technique [1, 2, 3, 4, 5, 6, 7] in which oxide powder of the appropriate stoichiometry and phase content is placed inside a metal tube, deformed into the desired geometry (round wire or flat tape), and annealed to produce the desired superconducting properties. Intermediate anneals are often incorporated between successive deformation steps. Silver is the metal used in this process because it is the most compatible with the reacting phase. In all of the commercial processes for BSCCO, Ag seems to play a special catalytic role promoting the growth of high performance aligned grains that grow in the first few micrometers near the Ag/BSCCO interface. Adjacent to the Ag, the grain alignment is more perfect and the current density is higher than in the center of the tape. It is known that Ag lowers the melting point of several of the phases but the detailed mechanism for growth of these high performance grains is not clearly understood. The purpose of this work is to study the nucleation and growth of the high performance material at this interface.

  20. Integrated Testing of a 4-Bed Molecular Sieve, Air-Cooled Temperature Swing Adsorption Compressor, and Sabatier Engineering Development Unit

    Science.gov (United States)

    Knox, James C.; Miller, Lee; Campbell, Melissa; Mulloth, Lila; Varghese, Mini

    2006-01-01

    Accumulation and subsequent compression of carbon dioxide that is removed from the space cabin are two important processes involved in a closed-loop air revitalization scheme of the International Space Station (ISS). The 4-Bed Molecular Sieve (4BMS) of ISS currently operates in an open loop mode without a compressor. The Sabatier Engineering Development Unit (EDU) processes waste CO2 to provide water to the crew. This paper reports the integrated 4BMS, air-cooled Temperature Swing Adsorption Compressor (TSAC), and Sabatier EDU testing. The TSAC prototype was developed at NASA Ames Research Center (ARC). The 4BMS was modified to a functionally flight-like condition at NASA Marshall Space Flight Center (MSFC). Testing was conducted at MSFC. The paper provides details of the TSAC operation at various CO2 loadings and corresponding performance of the 4BMS and Sabatier.

  1. Soil application of ash produced by low-temperature fluidized bed gasification: effects on soil nutrient dynamics and crop response

    DEFF Research Database (Denmark)

    Müller-Stöver, Dorette Sophie; Ahrenfeldt, Jesper; Holm, Jens Kai

    2012-01-01

    not significantly altered after ash application. SA was generally able to increase the levels of Olsen-P and of the ammonium acetate/acetic acid-extractable K in soil as well as to improve the yield of barley and maize, whereas faba bean did not react positively to ash amendment. CP did not show beneficial effects......Recycling of residual products of bioenergy conversion processes is important for adding value to the technologies and as a potential beneficial soil fertility amendment. In this study, two different ash materials originating from low temperature circulating fluidized bed (LT-CFB) gasification...... of either wheat straw (SA) or residue fibers mainly from citrus peels (CP) were tested regarding their potential to be used as fertilizer on agricultural soils. A soil incubation study, a greenhouse experiment with barley and faba bean, and an accompanying outdoor experiment with maize were carried out...

  2. Is high-resolution inverse characterization of heterogeneous river bed hydraulic conductivities needed and possible?

    Directory of Open Access Journals (Sweden)

    W. Kurtz

    2013-10-01

    Full Text Available River–aquifer exchange fluxes influence local and regional water balances and affect groundwater and river water quality and quantity. Unfortunately, river–aquifer exchange fluxes tend to be strongly spatially variable, and it is an open research question to which degree river bed heterogeneity has to be represented in a model in order to achieve reliable estimates of river–aquifer exchange fluxes. This research question is addressed in this paper with the help of synthetic simulation experiments, which mimic the Limmat aquifer in Zurich (Switzerland, where river–aquifer exchange fluxes and groundwater management activities play an important role. The solution of the unsaturated–saturated subsurface hydrological flow problem including river–aquifer interaction is calculated for ten different synthetic realities where the strongly heterogeneous river bed hydraulic conductivities (L are perfectly known. Hydraulic head data (100 in the default scenario are sampled from the synthetic realities. In subsequent data assimilation experiments, where L is unknown now, the hydraulic head data are used as conditioning information, with the help of the ensemble Kalman filter (EnKF. For each of the ten synthetic realities, four different ensembles of L are tested in the experiments with EnKF; one ensemble estimates high-resolution L fields with different L values for each element, and the other three ensembles estimate effective L values for 5, 3 or 2 zones. The calibration of higher-resolution L fields (i.e. fully heterogeneous or 5 zones gives better results than the calibration of L for only 3 or 2 zones in terms of reproduction of states, stream–aquifer exchange fluxes and parameters. Effective L for a limited number of zones cannot always reproduce the true states and fluxes well and results in biased estimates of net exchange fluxes between aquifer and stream. Also in case only 10 head data are used for conditioning, the high

  3. Application of High Temperature Superconductors to Accelerators

    CERN Document Server

    Ballarino, A

    2000-01-01

    Since the discovery of high temperature superconductivity, a large effort has been made by the scientific community to investigate this field towards a possible application of the new oxide superconductors to different devices like SMES, magnetic bearings, flywheels energy storage, magnetic shielding, transmission cables, fault current limiters, etc. However, all present day large scale applications using superconductivity in accelerator technology are based on conventional materials operating at liquid helium temperatures. Poor mechanical properties, low critical current density and sensitivity to the magnetic field at high temperature are the key parameters whose improvement is essential for a large scale application of high temperature superconductors to such devices. Current leads, used for transferring currents from the power converters, working at room temperature, into the liquid helium environment, where the magnets are operating, represent an immediate application of the emerging technology of high t...

  4. Dynamic Model of High Temperature PEM Fuel Cell Stack Temperature

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen

    2007-01-01

    cathode air cooled 30 cell HTPEM fuel cell stack developed at the Institute of Energy Technology at Aalborg University. This fuel cell stack uses PEMEAS Celtec P-1000 membranes, runs on pure hydrogen in a dead end anode configuration with a purge valve. The cooling of the stack is managed by running......The present work involves the development of a model for predicting the dynamic temperature of a high temperature PEM (HTPEM) fuel cell stack. The model is developed to test different thermal control strategies before implementing them in the actual system. The test system consists of a prototype...... the stack at a high stoichiometric air flow. This is possible because of the PBI fuel cell membranes used, and the very low pressure drop in the stack. The model consists of a discrete thermal model dividing the stack into three parts: inlet, middle and end and predicting the temperatures in these three...

  5. Experience in a 6.2 MW{sub e} pressurized fluidized bed gasifier with high ash Indian coals

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, G.; Rajasekaran, A.; Periyakaruppan, V.; Krishnamoorthy, S. [Bharat Heavy Electricals Ltd., Tiruchirappalli (India)

    2006-07-01

    Bharat Heavy Electrical Limited has installed a 165 tons/day air-blown pressurized fluidized bed gasifier (PFBG) as an add-on to their 6.2 MW IGCC demonstration plant and has operated it for more than 4000 hours. Improvements in the gasifier refractory lining, ash extraction and cooling devices, air distribution and temperature measuring devices were incorporated to improve the reliability and performance. Coal with 30-42% ash and high calorific value in the range of 15-20 MJ/kg was used during these operations with crushed coal of 1-4 mm as well as -6 mm coal with fines. Tests were conducted at gasifier pressure of 0.3-1.0 MPa, fluidized bed temperature of 980-1050{sup o}C and at various fluidized velocities and air to steam ratios. Once through carbon conversion efficiency of 90%, cold gas efficiency of 69% and dry gas calorific value of 4.4-4.6 MJ/Nm{sup 3} were obtained. About 15% char in fly ash (with 40% ash coal) was established by TGA. Seal pot system was added for recyling fly ash from the first cyclone to enhance carbon conversion, other parameters and to reduce the char in fly ash to acceptable level. Trends and correlations were established for constituents of gas, carbon conversion efficiency, cold gas efficiency, calorific value of gas and gas yield. BHEL is currently working with a partner to install a 125 MW IGCC plant. The paper elaborates the schematic and constructional details of the PFBG, operating experience and performance. 3 refs., 9 figs.

  6. Metaphysics methods development for high temperature gas cooled reactor analysis

    International Nuclear Information System (INIS)

    Seker, V.; Downar, T. J.

    2007-01-01

    Gas cooled reactors have been characterized as one of the most promising nuclear reactor concepts in the Generation-IV technology road map. Considerable research has been performed on the design and safety analysis of these reactors. However, the calculational tools being used to perform these analyses are not state-of-the-art and are not capable of performing detailed three-dimensional analyses. This paper presents the results of an effort to develop an improved thermal-hydraulic solver for the pebble bed type high temperature gas cooled reactors. The solution method is based on the porous medium approach and the momentum equation including the modified Ergun's resistance model for pebble bed is solved in three-dimensional geometry. The heat transfer in the pebble bed is modeled considering the local thermal non-equilibrium between the solid and gas, which results in two separate energy equations for each medium. The effective thermal conductivity of the pebble-bed can be calculated both from Zehner-Schluender and Robold correlations. Both the fluid flow and the heat transfer are modeled in three dimensional cylindrical coordinates and can be solved in steady-state and time dependent. The spatial discretization is performed using the finite volume method and the theta-method is used in the temporal discretization. A preliminary verification was performed by comparing the results with the experiments conducted at the SANA test facility. This facility is located at the Institute for Safety Research and Reactor Technology (ISR), Julich, Germany. Various experimental cases are modeled and good agreement in the gas and solid temperatures is observed. An on-going effort is to model the control rod ejection scenarios as described in the OECD/NEA/NSC PBMR-400 benchmark problem. In order to perform these analyses PARCS reactor simulator code will be coupled with the new thermal-hydraulic solver. Furthermore, some of the other anticipated accident scenarios in the benchmark

  7. Sandia_HighTemperatureComponentEvaluation_2015

    Energy Technology Data Exchange (ETDEWEB)

    Cashion, Avery T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    The objective of this project is to perform independent evaluation of high temperature components to determine their suitability for use in high temperature geothermal tools. Development of high temperature components has been increasing rapidly due to demand from the high temperature oil and gas exploration and aerospace industries. Many of these new components are at the late prototype or first production stage of development and could benefit from third party evaluation of functionality and lifetime at elevated temperatures. In addition to independent testing of new components, this project recognizes that there is a paucity of commercial-off-the-shelf COTS components rated for geothermal temperatures. As such, high-temperature circuit designers often must dedicate considerable time and resources to determine if a component exists that they may be able to knead performance out of to meet their requirements. This project aids tool developers by characterization of select COTS component performances beyond published temperature specifications. The process for selecting components includes public announcements of project intent (e.g., FedBizOps), direct discussions with candidate manufacturers,and coordination with other DOE funded programs.

  8. Materials corrosion and protection at high temperatures

    International Nuclear Information System (INIS)

    Balbaud, F.; Desgranges, Clara; Martinelli, Laure; Rouillard, Fabien; Duhamel, Cecile; Marchetti, Loic; Perrin, Stephane; Molins, Regine; Chevalier, S.; Heintz, O.; David, N.; Fiorani, J.M.; Vilasi, M.; Wouters, Y.; Galerie, A.; Mangelinck, D.; Viguier, B.; Monceau, D.; Soustelle, M.; Pijolat, M.; Favergeon, J.; Brancherie, D.; Moulin, G.; Dawi, K.; Wolski, K.; Barnier, V.; Rebillat, F.; Lavigne, O.; Brossard, J.M.; Ropital, F.; Mougin, J.

    2011-01-01

    This book was made from the lectures given in 2010 at the thematic school on 'materials corrosion and protection at high temperatures'. It gathers the contributions from scientists and engineers coming from various communities and presents a state-of-the-art of the scientific and technological developments concerning the behaviour of materials at high temperature, in aggressive environments and in various domains (aerospace, nuclear, energy valorization, and chemical industries). It supplies pedagogical tools to grasp high temperature corrosion thanks to the understanding of oxidation mechanisms. It proposes some protection solutions for materials and structures. Content: 1 - corrosion costs; macro-economical and metallurgical approach; 2 - basic concepts of thermo-chemistry; 3 - introduction to the Calphad (calculation of phase diagrams) method; 4 - use of the thermodynamic tool: application to pack-cementation; 5 - elements of crystallography and of real solids description; 6 - diffusion in solids; 7 - notions of mechanics inside crystals; 8 - high temperature corrosion: phenomena, models, simulations; 9 - pseudo-stationary regime in heterogeneous kinetics; 10 - nucleation, growth and kinetic models; 11 - test experiments in heterogeneous kinetics; 12 - mechanical aspects of metal/oxide systems; 13 - coupling phenomena in high temperature oxidation; 14 - other corrosion types; 15 - methods of oxidized surfaces analysis at micro- and nano-scales; 16 - use of SIMS in the study of high temperature corrosion of metals and alloys; 17 - oxidation of ceramics and of ceramic matrix composite materials; 18 - protective coatings against corrosion and oxidation; 19 - high temperature corrosion in the 4. generation of nuclear reactor systems; 20 - heat exchangers corrosion in municipal waste energy valorization facilities; 21 - high temperature corrosion in oil refining and petrochemistry; 22 - high temperature corrosion in new energies industry. (J.S.)

  9. High temperature thermometric phosphors for use in a temperature sensor

    Science.gov (United States)

    Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

    1998-01-01

    A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.(y), wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

  10. Viscoelastic creep of high-temperature concrete

    International Nuclear Information System (INIS)

    Pfeiffer, P.A.; Marchertas, A.H.; Bazant, Z.P.

    1985-01-01

    Presented in this report is the analytical model for analysis of high temperature creep response of concrete. The creep law used is linear (viscoelastic), the temperature and moisture effects on the creep rate and also aging are included. Both constant and transient temperature as well as constant and transient moisture conditions are considered. Examples are presented to correlate experimental data with parameters of the analytical model by the use of a finite element scheme

  11. High temperature tests for graphite materials

    OpenAIRE

    Zhmurikov, Evgenij

    2015-01-01

    This study was performed within the framework of the EURISOL for facilities SPIRAL-II (GANIL, France) and SPES (LNL, Italy), and aims to investigate the anticipated strength properties of fine-grained graphite at elevated temperatures. It appears that the major parameters that affect to the lifetime of a graphite target of this IP are the temperature and heating time. High temperature tests were conducted to simulate the heating under the influence of a beam of heavy particles by passing thro...

  12. Extension of PIV for measuring granular temperature field in dense fluidized beds.

    NARCIS (Netherlands)

    Dijkhuizen, W.; Bokkers, G.A.; Deen, N.G.; van Sint Annaland, M.; Kuipers, J.A.M.

    2007-01-01

    In this work a particle image velocimetry (PIV) technique has been extended to enable the simultaneous measurement of the instantaneous velocity and granular temperature fields. The PIV algorithm has been specifically optimized for dense granular systems and has been thoroughly tested with

  13. EFFECT OF CAGE BEDDING ON TEMPERATURE REGULATION AND METABOLISM OF GROUP-HOUSED FEMALE MICE.

    Science.gov (United States)

    This manuscript examines how methods used to house and study laboratory rodents could affect the variability and quality of toxicological data. The key finding is that there is likely to be more instability in body temperature and metabolism in mice when housed on conventional be...

  14. Thermohydraulic modeling of very high temperature reactors in regimes with loss of coolant using CFD

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Uebert G.; Dominguez, Dany S. [Universidade Estadual de Santa Cruz (UESC), Ilh´eus, BA (Brazil). Programa de P´os-Graduacao em Modelagem Computacional em Ciencia e Tecnologia; Mazaira, Leorlen Y.R.; Lira, Carlos A.B.O. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Hernandez, Carlos R.G., E-mail: uebert.gmoreira@gmail.com, E-mail: dsdominguez@gmail.com, E-mail: leored1984@gmail.com, E-mail: cabol@ufpe.br, E-mail: cgh@instec.cu [Instituto Superior de Tecnologas y Ciencias Aplicadas (InSTEC), La Habana (Cuba)

    2017-07-01

    The nuclear energy is a good alternative to meet the continuous increase in world energy demand. In this perspective, VHTRs (Very High Temperature Reactors) are serious candidates for energy generation due to its inherently safe performance, low power density and high conversion efficiency. However, the viability of these reactors depends on an efficient safety system in the operation of nuclear plants. The HTR (High Temperature Reactor)-10 model, an experimental reactor of the pebble bed type, is used as a case study in this work to perform the thermohydraulic simulation. Due to the complex patterns flow that appear in the pebble bed reactor core, and advances in computational capacity, CFD (Computational Fluid Dynamics) techniques are used to simulate these reactors. A realistic approach is adopted to simulate the central annular column of the reactor core, which each pebble bed element is modeled in detail. As geometrical model of the fuel elements was selected the BCC (Body Centered Cubic) arrangement. Previous works indicate this arrangement as the configuration that obtain higher fuel temperatures inside the core. Parameters considered for reactor design are available in the technical report of benchmark issues by IAEA (TECDOC-1694). Among the results obtained, we obtained the temperature profiles with different mass flow rates for the coolant. In general, the temperature distributions calculated are consistent with phenomenological behaviour. Even without consider the reactivity changes to reduce the reactor power or other safety procedures, the maximum temperatures do not exceed the recommended limits for fuel elements. (author)

  15. Thermohydraulic modeling of very high temperature reactors in regimes with loss of coolant using CFD

    International Nuclear Information System (INIS)

    Moreira, Uebert G.; Dominguez, Dany S.

    2017-01-01

    The nuclear energy is a good alternative to meet the continuous increase in world energy demand. In this perspective, VHTRs (Very High Temperature Reactors) are serious candidates for energy generation due to its inherently safe performance, low power density and high conversion efficiency. However, the viability of these reactors depends on an efficient safety system in the operation of nuclear plants. The HTR (High Temperature Reactor)-10 model, an experimental reactor of the pebble bed type, is used as a case study in this work to perform the thermohydraulic simulation. Due to the complex patterns flow that appear in the pebble bed reactor core, and advances in computational capacity, CFD (Computational Fluid Dynamics) techniques are used to simulate these reactors. A realistic approach is adopted to simulate the central annular column of the reactor core, which each pebble bed element is modeled in detail. As geometrical model of the fuel elements was selected the BCC (Body Centered Cubic) arrangement. Previous works indicate this arrangement as the configuration that obtain higher fuel temperatures inside the core. Parameters considered for reactor design are available in the technical report of benchmark issues by IAEA (TECDOC-1694). Among the results obtained, we obtained the temperature profiles with different mass flow rates for the coolant. In general, the temperature distributions calculated are consistent with phenomenological behaviour. Even without consider the reactivity changes to reduce the reactor power or other safety procedures, the maximum temperatures do not exceed the recommended limits for fuel elements. (author)

  16. Symposium on high temperature and materials chemistry

    International Nuclear Information System (INIS)

    1989-10-01

    This volume contains the written proceedings of the Symposium on High Temperature and Materials Chemistry held in Berkeley, California on October 24--25, 1989. The Symposium was sponsored by the Materials and Chemical Sciences Division of Lawrence Berkeley Laboratory and by the College of Chemistry of the University of California at Berkeley to discuss directions, trends, and accomplishments in the field of high temperature and materials chemistry. Its purpose was to provide a snapshot of high temperature and materials chemistry and, in so doing, to define status and directions

  17. Symposium on high temperature and materials chemistry

    Energy Technology Data Exchange (ETDEWEB)

    1989-10-01

    This volume contains the written proceedings of the Symposium on High Temperature and Materials Chemistry held in Berkeley, California on October 24--25, 1989. The Symposium was sponsored by the Materials and Chemical Sciences Division of Lawrence Berkeley Laboratory and by the College of Chemistry of the University of California at Berkeley to discuss directions, trends, and accomplishments in the field of high temperature and materials chemistry. Its purpose was to provide a snapshot of high temperature and materials chemistry and, in so doing, to define status and directions.

  18. High-temperature materials and structural ceramics

    International Nuclear Information System (INIS)

    1990-01-01

    This report gives a survey of research work in the area of high-temperature materials and structural ceramics of the KFA (Juelich Nuclear Research Center). The following topics are treated: (1) For energy facilities: ODS materials for gas turbine blades and heat exchangers; assessment of the remaining life of main steam pipes, material characterization and material stress limits for First-Wall components; metallic and graphitic materials for high-temperature reactors. (2) For process engineering plants: composites for reformer tubes and cracking tubes; ceramic/ceramic joints and metal/ceramic and metal/metal joints; Composites and alloys for rolling bearing and sliding systems up to application temperatures of 1000deg C; high-temperature corrosion of metal and ceramic material; porous ceramic high-temperature filters and moulding coat-mix techniques; electrically conducting ceramic material (superconductors, fuel cells, solid electrolytes); high-temperature light sources (high-temperature chemistry); oil vapor engines with caramic components; ODS materials for components in diesel engines and vehicle gas turbines. (MM) [de

  19. On high temperature strength of carbon steels

    International Nuclear Information System (INIS)

    Ichinose, Hiroyuki; Tamura, Manabu; Kanero, Takahiro; Ihara, Yoshihito

    1977-01-01

    In the steels for high temperature use, the oxidation resistance is regarded as important, but carbon steels show enough oxidation resistance to be used continuously at the temperature up to 500 deg. C if the strength is left out of consideration, and up to 450 deg. C even when the strength is taken into account. Moreover, the production is easy, the workability and weldability are good, and the price is cheap in carbon steels as compared with alloy steels. In the boilers for large thermal power stations, 0.15-0.30% C steels are used for reheater tubes, main feed water tubes, steam headers, wall water tubes, economizer tubes, bypass pipings and others, and they account for 70% of all steel materials used for the boilers of 350 MW class and 30% in 1000 MW class. The JIS standard for the carbon steels for high temperature use and the related standards in foreign countries are shown. The high temperature strength of carbon steels changes according to the trace elements, melting and heat treatment as well as the main compositions of C, Si and Mn. Al and N affect the high temperature strength largely. The characteristics of carbon steels after the heating for hours, the factors controlling the microstructure and high temperature strength, and the measures to improve the high temperature strength of carbon steels are explained. (Kako, I.)

  20. High performance biological methanation in a thermophilic anaerobic trickle bed reactor.

    Science.gov (United States)

    Strübing, Dietmar; Huber, Bettina; Lebuhn, Michael; Drewes, Jörg E; Koch, Konrad

    2017-12-01

    In order to enhance energy efficiency of biological methanation of CO 2 and H 2 , this study investigated the performance of a thermophilic (55°C) anaerobic trickle bed reactor (ATBR) (58.1L) at ambient pressure. With a methane production rate of up to 15.4m 3 CH4 /(m 3 trickle bed ·d) at methane concentrations above 98%, the ATBR can easily compete with the performance of other mixed culture methanation reactors. Control of pH and nutrient supply turned out to be crucial for stable operation and was affected significantly by dilution due to metabolic water production, especially during demand-orientated operation. Considering practical applications, inoculation with digested sludge, containing a diverse biocenosis, showed high adaptive capacity due to intrinsic biological diversity. However, no macroscopic biofilm formation was observed at thermophilic conditions even after 313days of operation. The applied approach illustrates the high potential of thermophilic ATBRs as a very efficient energy conversion and storage technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. New deployment of high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Sekimoto, Hiroshi; Tsuchie, Yasuo; Kunitomi, Kazuhiko; Shiozawa, Shusaku; Konuki, Kaoru; Inagaki, Yoshiyuki; Hayakawa, Hitoshi

    2002-01-01

    The high temperature gas-cooled reactor (HTGR) is now under a condition difficult to know it well, because of considering not only power generation, but also diverse applications of its nuclear heat, of having extremely different safe principle from that of conventional reactors, of having two types of pebble-bed and block which are extremely different types, of promoting its construction plan in South Africa, of including its application to disposition of Russian surplus weapons plutonium of less reporting HTTR in Japan in spite of its full operation, and so on. However, HTGR is expected for an extremely important nuclear reactor aiming at the next coming one of LWR. HTGR which is late started and developed under complete private leading, is strongly conscious at environmental problem since its beginning. Before 30 years when large scale HTGR was expected to operate, it advertised a merit to reduce wasted heat because of its high temperature. As ratio occupied by electricity expands among application of energies, ratio occupied by the other energies are larger. When considering applications except electric power, high temperature thermal energy from HTGR can be thought wider applications than that from LWR and so on. (G.K.)

  2. High temperature brazing of reactor materials

    International Nuclear Information System (INIS)

    Orlov, A.V.; Nechaev, V.A.; Rybkin, B.V.; Ponimash, I.D.

    1990-01-01

    Application of high-temperature brazing for joining products of such materials as molybdenum, tungsten, zirconium, beryllium, magnesium, nickel and aluminium alloys, graphite ceramics etc. is described. Brazing materials composition and brazed joints properties are presented. A satisfactory strength of brazed joints is detected under reactor operation temperatures and coolant and irradiation effect

  3. High-Resolution Adaptive Optics Test-Bed for Vision Science

    International Nuclear Information System (INIS)

    Wilks, S.C.; Thomspon, C.A.; Olivier, S.S.; Bauman, B.J.; Barnes, T.; Werner, J.S.

    2001-01-01

    We discuss the design and implementation of a low-cost, high-resolution adaptive optics test-bed for vision research. It is well known that high-order aberrations in the human eye reduce optical resolution and limit visual acuity. However, the effects of aberration-free eyesight on vision are only now beginning to be studied using adaptive optics to sense and correct the aberrations in the eye. We are developing a high-resolution adaptive optics system for this purpose using a Hamamatsu Parallel Aligned Nematic Liquid Crystal Spatial Light Modulator. Phase-wrapping is used to extend the effective stroke of the device, and the wavefront sensing and wavefront correction are done at different wavelengths. Issues associated with these techniques will be discussed

  4. Technology development for high temperature logging tools

    Energy Technology Data Exchange (ETDEWEB)

    Veneruso, A.F.; Coquat, J.A.

    1979-01-01

    A set of prototype, high temperature logging tools (temperature, pressure and flow) were tested successfully to temperatures up to 275/sup 0/C in a Union geothermal well during November 1978 as part of the Geothermal Logging Instrumentation Development Program. This program is being conducted by Sandia Laboratories for the Department of Energy's Division of Geothermal Energy. The progress and plans of this industry based program to develop and apply the high temperature instrumentation technology needed to make reliable geothermal borehole measurements are described. Specifically, this program is upgrading existing sondes for improved high temperature performance, as well as applying new materials (elastomers, polymers, metals and ceramics) and developing component technology such as high temperature cables, cableheads and electronics to make borehole measurements such as formation temperature, flow rate, high resolution pressure and fracture mapping. In order to satisfy critical existing needs, the near term goal is for operation up to 275/sup 0/C and 7000 psi by the end of FY80. The long term goal is for operation up to 350/sup 0/C and 20,000 psi by the end of FY84.

  5. High Temperature Superconductor Bolometers for Planetary Science

    Data.gov (United States)

    National Aeronautics and Space Administration — This work is a design study of an instrument optimized for JPL's novel high temperature superconductor bolometers. The work involves designing an imaging...

  6. Some theories of high temperature superconductivity

    International Nuclear Information System (INIS)

    Cohen, M.L.

    1990-01-01

    In this paper a brief review is given of some historical aspects of theoretical research on superconductivity including a discussion of BCS theory and some theoretical proposals for mechanisms which can cause superconductivity at high temperatures

  7. Panel report on high temperature ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Nolet, T C [ed.

    1979-01-01

    Fundamental research is reported concerning high temperature ceramics for application in turbines, engines, batteries, gasifiers, MHD, fuel cells, heat exchangers, and hot wall combustors. Ceramics microstructure and behavior are included. (FS)

  8. Novel High Temperature Strain Gauge, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced high-temperature sensor technology and bonding methods are of great interests in designing and developing advanced future aircraft. Current state-of-the-art...

  9. High-temperature turbopump assembly for space nuclear thermal propulsion

    Science.gov (United States)

    Overholt, David M.

    1993-01-01

    The development of a practical, high-performance nuclear rocket by the U.S. Air Force Space Nuclear Thermal Propulsion (SNTP) program places high priority on maximizing specific impulse (ISP) and thrust-to-weight ratio. The operating parameters arising from these goals drive the propellant-pump design. The liquid hydrogen propellant is pressurized and pumped to the reactor inlet by the turbopump assembly (TPA). Rocket propulsion is effected by rapid heating of the propellant from 100 K to thousands of degrees in the particle-bed reactor (PBR). The exhausted propellant is then expanded through a high-temperature nozzle. One approach to achieve high performance is to use an uncooled carbon-carbon nozzle and duct turbine inlet. The high-temperature capability is obtained by using carbon-carbon throughout the TPA hot section. Carbon-carbon components in development include structural parts, turbine nozzles/stators, and turbine rotors. The technology spinoff is applicable to conventional liquid propulsion engines plus a wide variety of other turbomachinery applications.

  10. High-temperature turbopump assembly for space nuclear thermal propulsion

    International Nuclear Information System (INIS)

    Overholt, D.M.

    1993-01-01

    The development of a practical, high-performance nuclear rocket by the U.S. Air Force Space Nuclear Thermal Propulsion (SNTP) program places high priority on maximizing specific impulse (ISP) and thrust-to-weight ratio. The operating parameters arising from these goals drive the propellant-pump design. The liquid hydrogen propellant is pressurized and pumped to the reactor inlet by the turbopump assembly (TPA). Rocket propulsion is effected by rapid heating of the propellant from 100 K to thousands of degrees in the particle-bed reactor (PBR). The exhausted propellant is then expanded through a high-temperature nozzle. One approach to achieve high performance is to use an uncooled carbon-carbon nozzle and duct turbine inlet. The high-temperature capability is obtained by using carbon-carbon throughout the TPA hot section. Carbon-carbon components in development include structural parts, turbine nozzles/stators, and turbine rotors. The technology spinoff is applicable to conventional liquid propulsion engines plus a wide variety of other turbomachinery applications

  11. High temperature superconductors and other superfluids

    CERN Document Server

    Alexandrov, A S

    2017-01-01

    Written by eminent researchers in the field, this text describes the theory of superconductivity and superfluidity starting from liquid helium and a charged Bose-gas. It also discusses the modern bipolaron theory of strongly coupled superconductors, which explains the basic physical properties of high-temperature superconductors. This book will be of interest to fourth year graduate and postgraduate students, specialist libraries, information centres and chemists working in high-temperature superconductivity.

  12. PLA recycling by hydrolysis at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Cristina, Annesini Maria; Rosaria, Augelletti; Sara, Frattari, E-mail: sara.frattari@uniroma1.it; Fausto, Gironi [Department of Chemical Engineering Materials Environment, University of Rome “La Sapienza”, Via Eudossiana 18– 00184 Roma (Italy)

    2016-05-18

    In this work the process of PLA hydrolysis at high temperature was studied, in order to evaluate the possibility of chemical recycling of this polymer bio-based. In particular, the possibility to obtain the monomer of lactic acid from PLA degradation was investigated. The results of some preliminary tests, performed in a laboratory batch reactor at high temperature, are presented: the experimental results show that the complete degradation of PLA can be obtained in relatively low reaction times.

  13. High-temperature reactor developments in the Netherlands

    International Nuclear Information System (INIS)

    Schram, R.P.C.; Cordfunke, E.H.P.; Heek, A.I. van.

    1996-01-01

    The high-temperature reactor development in the Netherland is embedded in the WHITE reactor program, in which several Dutch research institutes and engineering companies participate. The activities within the WHITE program are focused on the development of a small scale HTS for combined heat and power generation. In 1995, design choices for a pebble bed reactor were made at ECN. The first concept HTR will gave a closed cycle helium turbine and a power level of 40 MWth. It is intended to make the market introduction of a commercially competitive HTR feasible. The design will be an optimization of the Peu-a-Peu (PAP) concept of KFA Juelich. Computer codes necessary for the evaluation of reactor physics aspects of this reactor are developed in cooperation with international partners. An evaluation of a 20 MWth PAP concept showed that the maximum fuel termmperature after depressurization does not exceed 1300 C. (orig.)

  14. Close-Spaced High Temperature Knudsen Flow.

    Science.gov (United States)

    1986-07-15

    radiant heat source assembly was substituted for the brazed molybdenum one in order to achieve higher radiant heater temperatures . 2.1.4 Experimental...at very high temperature , and ground flat. The molybdenum is then chemically etched to the desired depth using an etchant which does not affect...RiB6 295 -CLSE PCED HIGH TEMPERATURE KNUDSEN FLOU(U) RASOR I AiASSOCIATES INC SUNNYVALE CA J 8 MCVEY 15 JUL 86 NSR-224 AFOSR-TR-87-1258 F49628-83-C

  15. High throughput photo-oxidations in a packed bed reactor system.

    Science.gov (United States)

    Kong, Caleb J; Fisher, Daniel; Desai, Bimbisar K; Yang, Yuan; Ahmad, Saeed; Belecki, Katherine; Gupton, B Frank

    2017-12-01

    The efficiency gains produced by continuous-flow systems in conducting photochemical transformations have been extensively demonstrated. Recently, these systems have been used in developing safe and efficient methods for photo-oxidations using singlet oxygen generated by photosensitizers. Much of the previous work has focused on the use of homogeneous photocatalysts. The development of a unique, packed-bed photoreactor system using immobilized rose bengal expands these capabilities as this robust photocatalyst allows access to and elaboration from these highly useful building blocks without the need for further purification. With this platform we were able to demonstrate a wide scope of singlet oxygen ene, [4+2] cycloadditions and heteroatom oxidations. Furthermore, we applied this method as a strategic element in the synthesis of the high-volume antimalarial artemisinin. Copyright © 2017. Published by Elsevier Ltd.

  16. High-rate wastewater treatment combining a moving bed biofilm reactor and enhanced particle separation.

    Science.gov (United States)

    Helness, H; Melin, E; Ulgenes, Y; Järvinen, P; Rasmussen, V; Odegaard, H

    2005-01-01

    Many cities around the world are looking for compact wastewater treatment alternatives since space for treatment plants is becoming scarce. In this paper development of a new compact, high-rate treatment concept with results from experiments in lab-scale and pilot-scale are presented. The idea behind the treatment concept is that coagulation/floc separation may be used to separate suspended and colloidal matter (resulting in > 70% organic matter removal in normal wastewater) while a high-rate biofilm process (based on Moving Bed biofilm reactors) may be used for removing low molecular weight, easily biodegradable, soluble organic matter. By using flotation for floc/biomass separation, the total residence time for a plant according to this concept will normally be treatment) and sufficient P-removal.

  17. Melt processed high-temperature superconductors

    CERN Document Server

    1993-01-01

    The achievement of large critical currents is critical to the applications of high-temperature superconductors. Recent developments have shown that melt processing is suitable for producing high J c oxide superconductors. Using magnetic forces between such high J c oxide superconductors and magnets, a person could be levitated.This book has grown largely out of research works on melt processing of high-temperature superconductors conducted at ISTEC Superconductivity Research Laboratory. The chapters build on melt processing, microstructural characterization, fundamentals of flux pinning, criti

  18. High Temperature, Wireless Seismometer Sensor for Venus

    Science.gov (United States)

    Ponchak, George E.; Scardelletti, Maximilian C.; Taylor, Brandt; Beard, Steve; Meredith, Roger D.; Beheim, Glenn M.; Hunter Gary W.; Kiefer, Walter S.

    2012-01-01

    Space agency mission plans state the need to measure the seismic activity on Venus. Because of the high temperature on Venus (462? C average surface temperature) and the difficulty in placing and wiring multiple sensors using robots, a high temperature, wireless sensor using a wide bandgap semiconductor is an attractive option. This paper presents the description and proof of concept measurements of a high temperature, wireless seismometer sensor for Venus. A variation in inductance of a coil caused by the movement of an aluminum probe held in the coil and attached to a balanced leaf-spring seismometer causes a variation of 700 Hz in the transmitted signal from the oscillator/sensor system at 426? C. This result indicates that the concept may be used on Venus.

  19. High temperature microscope (1961); Microscopie a haute temperature (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-06-15

    The purpose of this work is the realization of an apparatus for observation of radioactive metallic samples at high temperature and low pressure. The operating conditions are as follows: to limit oxidation of the metal, pressure of about 10{sup -6} mm of Hg is maintained in the furnace. In case the oxidation of the sample would be too important, on ultra vacuum. device could be used; working temperatures range between room temperature and 1200 deg. C; furnace temperature is regulated; observation is done ever in polarized light or interference contrast; to insure protection of the operator, the apparatus is placed in a glove-box. With that apparatus, we have observed the {alpha}{yields}{beta}, {beta}{yields}{gamma} transformations of uranium. A movie has been done. (author) [French] Le but de ce travail est la realisation d'une appareillage permettant l'observation a chaud et sous vide d'echantillons metalliques radioactifs. Cet appareillage fonctionne dans les conditions suivantes: l'echantillon est chauffe sous une pression de l'ordre de 10{sup -6} mm de mercure afin de limiter l'oxydation du materiau examine. L'utilisation eventuelle d'un groupe de pompage pour ultra vide est prevue; l'echantillon peut etre porte a une temperature comprise entre quelques degres et 1200 deg. C; la temperature du four est regulee; l'observation s'effectue soit en lumiere polarisee soit en contraste interferentiel; l'appareil est dipose dans une boite a gants afin d'assurer la protection de l'operateur contre les poussieres radioactives; Les transformations {alpha}{yields}{beta}, {beta}{yields}{gamma} de l'uranium ont ete observees. Un film a ete realise. (auteur)

  20. High-temperature granulites and supercontinents

    Directory of Open Access Journals (Sweden)

    J.L.R. Touret

    2016-01-01

    Full Text Available The formation of continents involves a combination of magmatic and metamorphic processes. These processes become indistinguishable at the crust-mantle interface, where the pressure-temperature (P-T conditions of (ultra high-temperature granulites and magmatic rocks are similar. Continents grow laterally, by magmatic activity above oceanic subduction zones (high-pressure metamorphic setting, and vertically by accumulation of mantle-derived magmas at the base of the crust (high-temperature metamorphic setting. Both events are separated from each other in time; the vertical accretion postdating lateral growth by several tens of millions of years. Fluid inclusion data indicate that during the high-temperature metamorphic episode the granulite lower crust is invaded by large amounts of low H2O-activity fluids including high-density CO2 and concentrated saline solutions (brines. These fluids are expelled from the lower crust to higher crustal levels at the end of the high-grade metamorphic event. The final amalgamation of supercontinents corresponds to episodes of ultra-high temperature metamorphism involving large-scale accumulation of these low-water activity fluids in the lower crust. This accumulation causes tectonic instability, which together with the heat input from the sub-continental lithospheric mantle, leads to the disruption of supercontinents. Thus, the fragmentation of a supercontinent is already programmed at the time of its amalgamation.

  1. Graphite for high-temperature reactors

    International Nuclear Information System (INIS)

    Hammer, W.; Leushacke, D.F.; Nickel, H.; Theymann, W.

    1976-01-01

    The different graphites necessary for HTRs are being developed, produced and tested within the Federal German ''Development Programme Nuclear Graphite''. Up to now, batches of the following graphite grades have been manufactured and fully characterized by the SIGRI Company to demonstrate reproducibility: pitch coke graphite AS2-500 for the hexagonal fuel elements and exchangeable reflector blocks; special pitch coke graphite ASI2-500 for reflector blocks of the pebble-bed reactor and as back-up material for the hexagonal fuel elements; graphite for core support columns. The material data obtained fulfill most of the requirements under present specifications. Production of large-size blocks for the permanent side reflector and the core support blocks is under way. The test programme covers all areas important for characterizing and judging HTR-graphites. In-pile testing comprises evaluation of the material for irradiation-induced changes of dimensions, mechanical and thermal properties - including behaviour under temperature cycling and creep behaviour - as well as irradiating fuel element segments and blocks. Testing out-of-pile includes: evaluation of corrosion rates and influence of corrosion on strength; strength measurements; including failure criteria. The test programme has been carried out extensively on the AS2-graphite, and the results obtained show that this graphite is suitable as HTGR fuel element graphite. (author)

  2. High-entropy alloys as high-temperature thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Shafeie, Samrand [Surface and Microstructure Engineering Group, Materials and Manufacturing Technology, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Guo, Sheng, E-mail: sheng.guo@chalmers.se [Surface and Microstructure Engineering Group, Materials and Manufacturing Technology, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Hu, Qiang [Institute of Applied Physics, Jiangxi Academy of Sciences, Nanchang 330029 (China); Fahlquist, Henrik [Bruker AXS Nordic AB, 17067 Solna (Sweden); Erhart, Paul [Department of Applied Physics, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Palmqvist, Anders, E-mail: anders.palmqvist@chalmers.se [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg (Sweden)

    2015-11-14

    Thermoelectric (TE) generators that efficiently recycle a large portion of waste heat will be an important complementary energy technology in the future. While many efficient TE materials exist in the lower temperature region, few are efficient at high temperatures. Here, we present the high temperature properties of high-entropy alloys (HEAs), as a potential new class of high temperature TE materials. We show that their TE properties can be controlled significantly by changing the valence electron concentration (VEC) of the system with appropriate substitutional elements. Both the electrical and thermal transport properties in this system were found to decrease with a lower VEC number. Overall, the large microstructural complexity and lower average VEC in these types of alloys can potentially be used to lower both the total and the lattice thermal conductivity. These findings highlight the possibility to exploit HEAs as a new class of future high temperature TE materials.

  3. High-temperature superconducting conductors and cables

    International Nuclear Information System (INIS)

    Peterson, D.E.; Maley, M.P.; Boulaevskii, L.; Willis, J.O.; Coulter, J.Y.; Ullmann, J.L.; Cho, Jin; Fleshler, S.

    1996-01-01

    This is the final report of a 3-year LDRD project at LANL. High-temperature superconductivity (HTS) promises more efficient and powerful electrical devices such as motors, generators, and power transmission cables; however this depends on developing HTS conductors that sustain high current densities J c in high magnetic fields at temperatures near liq. N2's bp. Our early work concentrated on Cu oxides but at present, long wire and tape conductors can be best made from BSCCO compounds with high J c at low temperatures, but which are degraded severely at temperatures of interest. This problem is associated with thermally activated motion of magnetic flux lines in BSCCO. Reducing these dc losses at higher temperatures will require a high density of microscopic defects that will pin flux lines and inhibit their motion. Recently it was shown that optimum defects can be produced by small tracks formed by passage of energetic heavy ions. Such defects result when Bi is bombarded with high energy protons. The longer range of protons in matter suggests the possibility of application to tape conductors. AC losses are a major limitation in many applications of superconductivity such as power transmission. The improved pinning of flux lines reduces ac losses, but optimization also involves other factors. Measuring and characterizing these losses with respect to material parameters and conductor design is essential to successful development of ac devices

  4. High-temperature reactor developments in the Netherlands

    International Nuclear Information System (INIS)

    Schram, R.P.C.; Cordfunke, E.H.P.; Heek, A.I. van

    1996-01-01

    The high-temperature reactor development in the Netherlands is embedded in the WHITE reactor program, in which several Dutch research institutes and engineering companies participate. The activities within the WHITE program are focused on the development of a small scale HTR for combined heat and power generation. In 1995, design choices for a pebble bed reactor were made at ECN. The first concept HTR will have a closed cycle helium turbine and a power level of 40 MWth. It is intended to make the market introduction of a commercially competitive HTR feasible. As a part of the HTR program at ECN, chemical aspects of HTR fuel and coated particles are studied. Experimental work on the oxidation resistance of coating materials and fission product attack on coating materials as well as thermochemical calculations of the fuel particles are done at ECN. The concept-HTR of ECN is fuelled with UO 2 , but the use of thorium is considered. The composition of the fuel determines the oxygen potential, which plays a key role in chemical safety of the fuel. Thermochemical calculations of the chemical form of cesium inside the HTR fuel particles were performed for a wide oxygen potential range. The chemical form of cesium determines the cesium pressure inside the fuel particle, which in turn determines the release behavior of Cs from defective particles. At normal operating temperatures and low oxygen potentials, the chemical form of cesium is C 60 Cs. It is known that cesium carbon compounds decompose above 650degC in vacuum. The stability of these compounds in the fuel particles at high temperatures(1000-1600degC) is questioned. Decomposition of these compounds may result in high cesium pressures even at normal operating conditions. Experimental work on the thermodynamic properties of cesium compounds at high temperatures is currently performed. (J.P.N.)

  5. High-temperature bulk acoustic wave sensors

    International Nuclear Information System (INIS)

    Fritze, Holger

    2011-01-01

    Piezoelectric crystals like langasite (La 3 Ga 5 SiO 14 , LGS) and gallium orthophosphate (GaPO 4 ) exhibit piezoelectrically excited bulk acoustic waves at temperatures of up to at least 1450 °C and 900 °C, respectively. Consequently, resonant sensors based on those materials enable new sensing approaches. Thereby, resonant high-temperature microbalances are of particular interest. They correlate very small mass changes during film deposition onto resonators or gas composition-dependent stoichiometry changes of thin films already deposited onto the resonators with the resonance frequency shift of such devices. Consequently, the objective of the work is to review the high-temperature properties, the operation limits and the measurement principles of such resonators. The electromechanical properties of high-temperature bulk acoustic wave resonators such as mechanical stiffness, piezoelectric and dielectric constant, effective viscosity and electrical conductivity are described using a one-dimensional physical model and determined accurately up to temperatures as close as possible to their ultimate limit. Insights from defect chemical models are correlated with the electromechanical properties of the resonators. Thereby, crucial properties for stable operation as a sensor under harsh conditions are identified to be the formation of oxygen vacancies and the bulk conductivity. Operation limits concerning temperature, oxygen partial pressure and water vapor pressure are given. Further, application-relevant aspects such as temperature coefficients, temperature compensation and mass sensitivity are evaluated. In addition, approximations are introduced which make the exact model handy for routine data evaluation. An equivalent electrical circuit for high-temperature resonator devices is derived based on the one-dimensional physical model. Low- and high-temperature approximations are introduced. Thereby, the structure of the equivalent circuit corresponds to the

  6. High-temperature bulk acoustic wave sensors

    Science.gov (United States)

    Fritze, Holger

    2011-01-01

    Piezoelectric crystals like langasite (La3Ga5SiO14, LGS) and gallium orthophosphate (GaPO4) exhibit piezoelectrically excited bulk acoustic waves at temperatures of up to at least 1450 °C and 900 °C, respectively. Consequently, resonant sensors based on those materials enable new sensing approaches. Thereby, resonant high-temperature microbalances are of particular interest. They correlate very small mass changes during film deposition onto resonators or gas composition-dependent stoichiometry changes of thin films already deposited onto the resonators with the resonance frequency shift of such devices. Consequently, the objective of the work is to review the high-temperature properties, the operation limits and the measurement principles of such resonators. The electromechanical properties of high-temperature bulk acoustic wave resonators such as mechanical stiffness, piezoelectric and dielectric constant, effective viscosity and electrical conductivity are described using a one-dimensional physical model and determined accurately up to temperatures as close as possible to their ultimate limit. Insights from defect chemical models are correlated with the electromechanical properties of the resonators. Thereby, crucial properties for stable operation as a sensor under harsh conditions are identified to be the formation of oxygen vacancies and the bulk conductivity. Operation limits concerning temperature, oxygen partial pressure and water vapor pressure are given. Further, application-relevant aspects such as temperature coefficients, temperature compensation and mass sensitivity are evaluated. In addition, approximations are introduced which make the exact model handy for routine data evaluation. An equivalent electrical circuit for high-temperature resonator devices is derived based on the one-dimensional physical model. Low- and high-temperature approximations are introduced. Thereby, the structure of the equivalent circuit corresponds to the Butterworth

  7. Programmes and projects for high-temperature reactor development

    International Nuclear Information System (INIS)

    Bogusch, Edgar; Hittner, Dominique

    2009-01-01

    An increasing attention has to be recognised worldwide on the development of High-Temperature Reactors (HTR) which has started in Germany and other countries in the 1970ies. While pebble bed reactors with spherical fuel elements have been developed and constructed in Germany, countries such as France, the US and Russia investigated HTR concepts with prismatic block-type fuel elements. The concept of a modular HTR formerly developed by Areva NP was an essential basis for the HTR-10 in China. A pebble bed HTR for electricity production is developed in South Africa. The construction is planned after the completion of the licensing procedure. Also the US is planning an HTR under the NGNP (Next Generation Nuclear Plant) Project. Due to the high temperature level of the helium coolant, the HTR can be used not only for electricity production but also for supply of process heat. Including its inherent safety features the HTR is an attractive candidate for heat supply to various types of plants e.g. for hydrogen production or coal liquefactions. The conceptual design of an HTR with prismatic fuel elements for the cogeneration of electricity and process heat has been developed by Areva NP. On the European scale the HTR development is promoted by the RAPHAEL (ReActor for Process heat, Hydrogen And ELectricity generation) project. RAPHAEL is an Integrated Project of the Euratom 6th Framework Programme for the development of technologies towards a Very High-Temperature Reactor (VHTR) for the production of electricity and heat. It is financed jointly by the European Commission and the partners of the HTR Technology Network (HTR-TN) and coordinated by Areva NP. The RAPHAEL project not only promotes HTR development but also the cooperation with other European projects such as the material programme EXTREMAT. Furthermore HTR technology is investigated in the frame of Generation IV International Forum (GIF). The development of a VHTR with helium temperatures above 900 C for the

  8. High temperature gas cleaning for pressurized gasification. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Alden, H.; Hagstroem, P.; Hallgren, A.; Waldheim, L. [TPS Termiska Processer AB, Nykoeping (Sweden)

    2000-04-01

    The purpose of the project was to build an apparatus to study pressurized, high temperature gas cleaning of raw gasification gas generated from biomass. A flexible and easy to operate pressurized apparatus was designed and installed for the investigations in high temperature gas cleaning by means of thermal, catalytic or chemical procedures. A semi continuos fuel feeding concept, at a maximum rate of 700 g/h, allowed a very constant formation of a gas product at 700 deg C. The gas product was subsequently introduced into a fixed bed secondary reactor where the actual gas cleanup or reformation was fulfilled. The installation work was divided into four work periods and apart from a few delays the work was carried out according to the time plan. During the first work period (January - June 1994) the technical design, drawings etc. of the reactor and additional parts were completed. All material for the construction was ordered and the installation work was started. The second work period (July - December 1994) was dedicated to the construction and the installation of the different components. Initial tests with the electrical heating elements, control system and gas supply were assigned to the third work period (January - June 1995). After the commissioning and the resulting modifications, initial pyrolysis and tar decomposition experiments were performed. During the fourth and final work period, (June - December 1995) encouraging results from first tests allowed the experimental part of the project work to commence, however in a slightly reduced program. The experimental part of the project work comparatively studied tar decomposition as a function of the process conditions as well as of the choice of catalyst. Two different catalysts, dolomite and a commercial Ni-based catalyst, were evaluated in the unit. Their tar cracking ability in the pressure interval 1 - 20 bar and at cracker bed temperatures between 800 - 900 deg C was compared. Long term tests to study

  9. Ion filter for high temperature cleaning

    International Nuclear Information System (INIS)

    Kutomi, Yasuhiro; Nakamori, Masaharu.

    1994-01-01

    A porous ceramic pipe mainly comprising alumina is used as a base pipe, and then crud and radioactive ion adsorbing materials in high temperature and high pressure water mainly comprising a FeTiO 3 compound are flame-coated on the outer surface thereof to a film thickness of about 100 to 300μ m as an aimed value by an acetylene flame-coating method. The flame-coated FeTiO 3 layer is also porous, so that high temperature and high pressure water to be cleaned can pass through from the inside to the outside of the pipe. Cruds can be removed and radioactive ions can be adsorbed during passage. Since all the operations can be conducted at high temperature and high pressure state, cooling is no more necessary for the high temperature and high pressure water to be cleaned, heat efficiency of the plant can be improved and a cooling facility can be saved. Further, since the flame-coating of FeTiO 3 to the porous ceramic pipe can be conducted extremely easily compared with production of a sintering product, cost for the production of filter elements can be saved remarkably. (T.M.)

  10. High temperature phase transitions without infrared divergences

    International Nuclear Information System (INIS)

    Tetradis, N.; Wetterich, C.

    1993-09-01

    The most commonly used method for the study of high temperature phase transitions is based on the perturbative evaluation of the temperature dependent effective potential. This method becomes unreliable in the case of a second order or weakly first order phase transition, due to the appearance of infrared divergences. These divergences can be controlled through the method of the effective average action which employs renormalization group ideas. We report on the study of the high temperature phase transition for the N-component φ 4 theory. A detailed quantitative picture of the second order phase transition is presented, including the critical exponents for the behaviour in the vicinity of the critical temperature. An independent check of the results is obtained in the large N limit, and contact with the perturbative approach is established through the study of the Schwinger-Dyson equations. (orig.)

  11. Low temperature circulating fluidized bed gasification and co-gasification of municipal sewage sludge

    DEFF Research Database (Denmark)

    Thomsen, Tobias Pape; Hauggaard-Nielsen, Henrik; Gøbel, Benny

    2017-01-01

    to the mono-sludge ashes, thereby showing the best fertilizer qualities among all assessed materials. It was also found that bottom ashes from the char reactor contained even less heavy metals than cyclone ashes. It is concluded that LT-CFB gasification and co-gasification is a highly effective way to purify...

  12. High temperature estimation through computer vision

    International Nuclear Information System (INIS)

    Segovia de los R, J.A.

    1996-01-01

    The form recognition process has between his purposes to conceive and to analyze the classification algorithms applied to the image representations, sounds or signals of any kind. In a process with a thermal plasma reactor in which cannot be employed conventional dispositives or methods for the measurement of the very high temperatures. The goal of this work was to determine these temperatures in an indirect way. (Author)

  13. Applications of high-temperature superconductivity

    International Nuclear Information System (INIS)

    Malozemoff, A.P.; Gallagher, W.J.; Schwall, R.E.

    1987-01-01

    The new high temperature superconductors open up possibilities for applications in magnets, power transmission, computer interconnections, Josephson devices and instrumentation, among many others. The success of these applications hinges on many interlocking factors, including critical current density, critical fields, allowable processing temperatures, mechanical properties and chemical stability. An analysis of some of these factors suggests which applications may be the easiest to realize and which may have the greatest potential

  14. Modeling of concrete response at high temperature

    International Nuclear Information System (INIS)

    Pfeiffer, P.; Marchertas, A.

    1984-01-01

    A rate-type creep law is implemented into the computer code TEMP-STRESS for high temperature concrete analysis. The disposition of temperature, pore pressure and moisture for the particular structure in question is provided as input for the thermo-mechanical code. The loss of moisture from concrete also induces material shrinkage which is accounted for in the analytical model. Examples are given to illustrate the numerical results

  15. Fluidized-bed calciner with combustion nozzle and shroud

    International Nuclear Information System (INIS)

    Wielang, J.A.; Palmer, W.B.; Kerr, W.B.

    1977-01-01

    A nozzle employed as a burner within a fluidized bed is coaxially enclosed within a tubular shroud that extends beyond the nozzle length into the fluidized bed. The open-ended shroud portion beyond the nozzle end provides an antechamber for mixture and combustion of atomized fuel with an oxygen-containing gas. The arrangement provides improved combustion efficiency and excludes bed particles from the high-velocity, high-temperature portions of the flame to reduce particle attrition. 4 claims, 2 figures

  16. Raman spectroscopy in high temperature chemistry

    International Nuclear Information System (INIS)

    Drake, M.C.; Rosenblatt, G.M.

    1979-01-01

    Raman spectroscopy (largely because of advances in laser and detector technology) is assuming a rapidly expanding role in many areas of research. This paper reviews the contribution of Raman spectroscopy in high temperature chemistry including molecular spectroscopy on static systems and gas diagnostic measurements on reactive systems. An important aspect of high temperature chemistry has been the identification and study of the new, and often unusual, gaseous molecules which form at high temperatures. Particularly important is the investigation of vibrational-rotational energy levels and electronic states which determine thermodynamic properties and describe chemical bonding. Some advantages and disadvantages of high temperature Raman spectrosocpy for molecular studies on static systems are compared: (1) Raman vs infrared; (2) gas-phase vs condensed in matries; and (3) atmospheric pressure Raman vs low pressure techniques, including mass spectroscopy, matrix isolation, and molecular beams. Raman studies on molecular properties of gases, melts, and surfaces are presented with emphasis on work not covered in previous reviews of high temperature and matrix isolation Raman spectroscopy

  17. Raman spectroscopy in high temperature chemistry

    International Nuclear Information System (INIS)

    Drake, M.C.; Rosenblatt, G.M.

    1979-01-01

    Raman spectroscopy (largely because of advances in laser and detector technology) is assuming a rapidly expanding role in many areas of research. This paper reviews the contribution of Raman spectroscopy in high temperature chemistry including molecular spectroscopy on static systems and gas diagnostic measurements on reactive systems. An important aspect of high temperature chemistry has been the identification and study of the new, and often unusual, gaseous molecules which form at high temperatures. Particularly important is the investigation of vibrational-rotational energy levels and electronic states which determine thermodynamic properties and describe chemical bonding. Some advantages and disadvantages of high temperature Raman spectrosocpy for molecular studies on static systems are compared: (1) Raman vs infrared; (2) gas-phase vs condensed in matrices; and (3) atmospheric pressure Raman vs low pressure techniques, including mass spectroscopy, matrix isolation, and molecular beams. Raman studies on molecular properties of gases, melts, and surfaces are presented with emphasis on work not covered in previous reviews of high temperature and matrix isolation Raman spectroscopy

  18. CFD Analysis of the Fuel Temperature in High Temperature Gas-Cooled Reactors

    International Nuclear Information System (INIS)

    In, W. K.; Chun, T. H.; Lee, W. J.; Chang, J. H.

    2005-01-01

    High temperature gas-cooled reactors (HTGR) have received a renewed interest as potential sources for future energy needs, particularly for a hydrogen production. Among the HTGRs, the pebble bed reactor (PBR) and a prismatic modular reactor (PMR) are considered as the nuclear heat source in Korea's nuclear hydrogen development and demonstration project. PBR uses coated fuel particles embedded in spherical graphite fuel pebbles. The fuel pebbles flow down through the core during an operation. PMR uses graphite fuel blocks which contain cylindrical fuel compacts consisting of the fuel particles. The fuel blocks also contain coolant passages and locations for absorber and control material. The maximum fuel temperature in the core hot spot is one of the important design parameters for both PBR and PMR. The objective of this study is to predict the fuel temperature distributions in PBR and PMR using a computational fluid dynamics(CFD) code, CFX-5. The reference reactor designs used in this analysis are PBMR400 and GT-MHR600

  19. Thermal treatment of high-caloric waste in fluidized bed incineration plants in Austria

    International Nuclear Information System (INIS)

    Ragossnig, A.M.

    2001-05-01

    The importance of thermal treatment of waste and residues in Austria is expected to rise due to the current changes of the legal situation in waste management. Assessing the rank order of different thermal treatment processes for waste management it has been shown that - especially caused by the rising importance of the mechanical treatment step in the mechanical-biological residual waste treatment and the subsequent necessity of the thermal treatment of a high-caloric preprocessed waste stream - the importance of the fluidized bed technology will increase. The main advantages are the high existing capacities as well as the flexibility of this technology in regard of fuel properties and further on the fact of the lacking influence of the ash towards the quality of a product. This is true although the thermal treatment in fluidized bed incinerators requires some processing of the waste. This doctoral thesis also contains a thorough physical and chemical characterization of various waste fuels - especially those which have been used during full scale incineration experiments. This characterization includes a comparison with fossil fuel. The practical part contains the documentation and balancing of full scale incineration experiments. A comparison of a reference experiment with experiments when waste fuel has been thermally utilized showed that a significant increase of emissions to the atmosphere has not been observed. Based on the incineration experiments conclusions in regard of waste fuels as well as different categories of thermal treatment plants are being stated. Finally, a recommendation of the assignation of various waste streams to different categories of thermal treatment plants is being made. (author)

  20. Potentialities of high temperature reactors (HTR)

    International Nuclear Information System (INIS)

    Hittner, D.

    2001-01-01

    This articles reviews the assets of high temperature reactors concerning the amount of radioactive wastes produced. 2 factors favors HTR-type reactors: high thermal efficiency and high burn-ups. The high thermal efficiency is due to the high temperature of the coolant, in the case of the GT-MHR project (a cooperation between General Atomic, Minatom, Framatome, and Fuji Electric) designed to burn Russian military plutonium, the expected yield will be 47% with an outlet helium temperature of 850 Celsius degrees. The high temperature of the coolant favors a lot of uses of the heat generated by the reactor: urban heating, chemical processes, or desalination of sea water.The use of a HTR-type reactor in a co-generating way can value up to 90% of the energy produced. The high burn-up is due to the technology of HTR-type fuel that is based on encapsulation of fuel balls with heat-resisting materials. The nuclear fuel of Fort-Saint-Vrain unit (Usa) has reached values of burn-ups from 100.000 to 120.000 MWj/t. It is shown that the quantity of unloaded spent fuel can be divided by 4 for the same amount of electricity produced, in the case of the GT-MHR project in comparison with a light water reactor. (A.C.)

  1. High resolution field study of sediment dynamics on a strongly heterogeneous bed

    Science.gov (United States)

    Bailly Du Bois, P.; Blanpain, O.; Lafite, R.; Cugier, P.; Lunven, M.

    2010-12-01

    Extensive field measurements have been carried out at several stations in a macrotidal inner continental shelf in the English Channel (around 25 m depth) during spring tide period. The strong tidal current measured (up to 1.6 m.s-1) allowed sediment dynamics on a bed characterised by a mixture of size with coarse grains to be dominant. Data acquired in such hydro-sedimentary conditions are scarce. A new instrument, the DYnamic Sediment Profile Imagery (DySPI) system, was specifically conceived and implemented in-situ to observe and measure, with a high temporal resolution, the dynamics of a strongly heterogeneous mixture of particles in a grain-size scale. The data collected covered: 1) grain size range (side scan sonar, video observations, Shipeck grab samples, DySPI images) and vertical sorting (stratigraphic sampling by divers) of sediment cover, 2) hydrodynamic features (acoustic Doppler velocimeter, acoustic Doppler profiler), 3) suspended load nature and dynamics (optical backscatter, chlorophyll fluorometer, particle size analyser, Niskin bottles, scanning electron microscopy), 4) sand and gravel bedload transport estimates (DySPI image processing), 5) transfer dynamics of fine grains within a coarse matrix and their depth of penetration (radionuclides measurements in stratigraphic samples). The four stations present different grain size vertical sorting from a quasi-permanent armouring to a homogenous distribution. The sediment cover condition is directly linked to hydrodynamic capacity and sediment availability. Fine grain ratio within deep sediment layers (up to 10 cm) is higher when the bed armouring is durable. However, fine sediments are not permanently depth trapped: deep layers are composed of few years-old radionuclide tracers fixed on fine grains and a vertical mixing coefficient has been evaluated for each sediment cover. Fine grain dynamics within a coarse matrix is inversely proportional to the robustness of the armour layer. For current

  2. High temperature superconductivity the road to higher critical temperature

    CERN Document Server

    Uchida, Shin-ichi

    2015-01-01

    This book presents an overview of material-specific factors that influence Tc and give rise to diverse Tc values for copper oxides and iron-based high- Tc superconductors on the basis of more than 25 years of experimental data, to most of which the author has made important contributions. The book then explains why both compounds are distinct from others with similar crystal structure and whether or not one can enhance Tc, which in turn gives a hint on the unresolved pairing mechanism. This is an unprecedented new approach to the problem of high-temperature superconductivity and thus will be inspiring to both specialists and non-specialists interested in this field.   Readers will receive in-depth information on the past, present, and future of high-temperature superconductors, along with special, updated information on what the real highest Tc values are and particularly on the possibility of enhancing Tc for each member material, which is important for application. At this time, the highest Tc has not been...

  3. High transition temperature superconducting integrated circuit

    International Nuclear Information System (INIS)

    DiIorio, M.S.

    1985-01-01

    This thesis describes the design and fabrication of the first superconducting integrated circuit capable of operating at over 10K. The primary component of the circuit is a dc SQUID (Superconducting QUantum Interference Device) which is extremely sensitive to magnetic fields. The dc SQUID consists of two superconductor-normal metal-superconductor (SNS) Josephson microbridges that are fabricated using a novel step-edge process which permits the use of high transition temperature superconductors. By utilizing electron-beam lithography in conjunction with ion-beam etching, very small microbridges can be produced. Such microbridges lead to high performance dc SQUIDs with products of the critical current and normal resistance reaching 1 mV at 4.2 K. These SQUIDs have been extensively characterized, and exhibit excellent electrical characteristics over a wide temperature range. In order to couple electrical signals into the SQUID in a practical fashion, a planar input coil was integrated for efficient coupling. A process was developed to incorporate the technologically important high transition temperature superconducting materials, Nb-Sn and Nb-Ge, using integrated circuit techniques. The primary obstacles were presented by the metallurgical idiosyncrasies of the various materials, such as the need to deposit the superconductors at elevated temperatures, 800-900 0 C, in order to achieve a high transition temperature

  4. Bed Agglomeration During the Steam Gasification of a High Lignin Corn Stover Simultaneous Saccharification and Fermentation (SSF) Digester Residue

    Energy Technology Data Exchange (ETDEWEB)

    Howe, Daniel T.; Taasevigen, Danny J.; Gerber, Mark A.; Gray, Michel J.; Fernandez, Carlos A.; Saraf, Laxmikant; Garcia-Perez, Manuel; Wolcott, Michael P.

    2015-11-13

    This research investigates the bed agglomeration phenomena during the steam gasification of a high lignin residue produced from the simultaneous saccharification and fermentation (SSF) of corn stover in a bubbling fluidized bed. The studies were conducted at 895°C using alumina as bed material. Biomass was fed at 1.5 kg/hr, while steam was fed to give a velocity equal to 2.5 times the minimum fluidization velocity, with a steam/carbon ratio of 0.9. The pelletized feedstock was co-fed with a cooling nitrogen stream to mitigate feed line plugging issues. Tar production was high at 50.3 g/Nm3, and the fraction of C10+ compounds was greater than that seen in the gasification of traditional lignocellulosic feedstocks. Carbon closures over 94 % were achieved for all experiments. Bed agglomeration was found to be problematic, indicated by pressure drop increases observed below the bed and upstream of the feed line. Two size categories of solids were recovered from the reactor, +60 mesh and -60 mesh. After a 2.75-hour experiment, 61.7 wt % was recovered as -60 mesh particles and 38.2 wt% of the recovered reactor solids were +60 mesh. A sizeable percentage, 31.8 wt%, was +20 mesh. The -60 mesh particles were mainly formed by the initial bed material (Al2O3). Almost 50 wt. % of the + 20 mesh particles was found to be formed by organics. The unreacted carbon remaining in the reactor resulted in a low conversion rate to product gas. ICP-AES, SEM, SEM-EDS, and XRD confirmed that the large agglomerates (+ 20 mesh) were not encapsulated bed material but rather un-gasified feedstock pellets with sand particles attached to it.

  5. Bed Bugs

    Science.gov (United States)

    Prevent, identify, and treat bed bug infestations using EPA’s step-by-step guides, based on IPM principles. Find pesticides approved for bed bug control, check out the information clearinghouse, and dispel bed bug myths.

  6. EXPERIMENTAL STUDY OF HIGH LEVELS OF SO2 REMOVAL IN ATMOSPHERIC-PRESSURE FUIDIZED-BED COMBUSTORS

    Science.gov (United States)

    The report describes tests conducted in an atmospheric-pressure-fluidized-bed combustor (FBC) with a cross-section of 1 x 1.6 m) to demonstrate high levels of S02 removal when burning a high-sulfur coal and feeding limestone sorbent for S02 removal. The goal was to achieve 90-plu...

  7. Highly demanding resistive vibration exercise program is tolerated during 56 days of strict bed-rest.

    NARCIS (Netherlands)

    Rittweger, J.; Belavy, D.; Hunek, P.; Gast, U.; Boerst, H.; Feilcke, B.; Armbrecht, G.; Mulder, E.R.; Schubert, H.; Richardson, C.; de Haan, A.; Stegeman, D.F.; Schiessl, H.; Felsenberg, D.

    2006-01-01

    Several studies have tried to find countermeasures against musculoskeletal de-conditioning during bed rest, but none of them yielded decisive results. We hypothesised that resistive vibration exercise (RVE) might be a suitable training modality. We have therefore carried out a bed-rest study to

  8. Highly demanding resistive vibration exercise program is tolerated during 56 days of strict bed-rest.

    NARCIS (Netherlands)

    Rittweger, J.; Belavy, D.; Hunek, P.; Gast, U.; Boerst, H.; Feilcke, B.; Armbrecht, G.; Mulder, E.; Schubert, H.; Richardson, C.; Haan, A. de; Stegeman, D.F.; Schiessl, H.; Felsenberg, D.

    2006-01-01

    Several studies have tried to find countermeasures against musculoskeletal de-conditioning during bed-rest, but none of them yielded decisive results. We hypothesised that resistive vibration exercise (RVE) might be a suitable training modality. We have therefore carried out a bed-rest study to

  9. Brazing, high temperature brazing and diffusion welding

    International Nuclear Information System (INIS)

    1989-01-01

    Brazing and high temperature brazing is a major joining technology within the economically important fields of energy technology, aerospace and automotive engineering, that play a leading role for technical development everywhere in the world. Moreover diffusion welding has gained a strong position especially in advanced technologies due to its specific advantages. Topics of the conference are: 1. high-temperature brazing in application; 2. basis of brazing technology; 3. brazing of light metals; 4. nondestructive testing; 5. diffusion welding; 6. brazing of hard metals and other hard materials; and 7. ceramic-metal brazing. 28 of 20 lectures and 20 posters were recorded separately for the database ENERGY. (orig./MM) [de

  10. Materials for high-temperature fuel cells

    CERN Document Server

    Jiang, San Ping; Lu, Max

    2013-01-01

    There are a large number of books available on fuel cells; however, the majority are on specific types of fuel cells such as solid oxide fuel cells, proton exchange membrane fuel cells, or on specific technical aspects of fuel cells, e.g., the system or stack engineering. Thus, there is a need for a book focused on materials requirements in fuel cells. Key Materials in High-Temperature Fuel Cells is a concise source of the most important and key materials and catalysts in high-temperature fuel cells with emphasis on the most important solid oxide fuel cells. A related book will cover key mater

  11. Initial stages of high temperature metal oxidation

    International Nuclear Information System (INIS)

    Yang, C.Y.; O'Grady, W.E.

    1981-01-01

    The application of XPS and UPS to the study of the initial stages of high temperature (> 350 0 C) electrochemical oxidation of iron and nickel is discussed. In the high temperature experiments, iron and nickel electrodes were electrochemically oxidized in contact with a solid oxide electrolyte in the uhv system. The great advantages of this technique are that the oxygen activity at the interface may be precisely controlled and the ability to run the reactions in uhv allows the simultaneous observation of the reactions by XPS

  12. High temperature giant dipole and isoscalar resonances

    International Nuclear Information System (INIS)

    Navarro, J.; Barranco, M.; Garcias, F.; Suraud, E.

    1990-01-01

    We present a systematic study of the Giant Dipole Resonance (GDR) at high temperatures (T > ∼ 4 MeV) in the framework of a semi-classical approximation that uses the m 1 and m 3 RPA sum rules to estimate the GDR mean energy. We focus on the evolution with T of the collective nature of the GDR and of the L = 0,2,3 and 4 isoscalar resonances. We find that the GDR remains particularly collective at high T, suggesting that it might be possible to observe it experimentally even at temperatures close to the maximum one a nucleus can sustain

  13. Thermal treatment of soil co-contaminated with lube oil and heavy metals in a low-temperature two-stage fluidized bed incinerator

    International Nuclear Information System (INIS)

    Samaksaman, Ukrit; Peng, Tzu-Huan; Kuo, Jia-Hong; Lu, Chien-Hsing; Wey, Ming-Yen

    2016-01-01

    Highlights: • Low-temperature two-stage fluidized bed incineration was applied for soil remediation. • Co-firing of polyethylene with co-contaminated soil was studied. • Co-firing of polyethylene in soil remediation can promote residue quality. • The leachability of heavy metals passed the regulatory threshold values. - Abstract: This study presents the application of a low-temperature two-stage fluidized bed incinerator to remediate contaminants in the soil. The system was designed to control emissions of both gaseous pollutants and heavy metals during combustion. Soil co-contaminated with lube oil and heavy metals such as cadmium, chromium, copper, and lead was examined. Experiments were conducted by estimating various parameters such as operating temperature in the first-stage reactor (500–700 °C), ratio of sand bed height/diameter in the second-stage reactor (H/D: 3, 4, 6), and gas velocity (0.21–0.29 m/s). Heavy metal and gaseous pollutant emissions were also investigated during contaminated soil co-firing with polyethylene. The experimental results indicated that the destruction and removal efficiency of lube oil in treated soil products ranged from 98.27 to 99.93%. On the other hand, leaching tests of bottom ashes illustrated that heavy metals such as chromium, copper, and lead in leachates were complied with the regulations. For gaseous emissions, carbon monoxide concentrations decreased apparently with increasing ratio of sand bed height/diameter in the second-stage reactor. The increase of gas velocity had significant potential to generate the lowest carbon monoxide and particulate matter emissions. Nevertheless, during co-firing with polyethylene, emissions of organic pollutants such as benzene, toluene, ethylbenzene, and xylene and polycyclic aromatic hydrocarbons decrease by using the low-temperature two-stage fluidized bed incineration system.

  14. Defluidization in fluidized bed gasifiers using high-alkali content fuels

    DEFF Research Database (Denmark)

    Narayan, Vikas; Jensen, Peter Arendt; Henriksen, Ulrik Birk

    2016-01-01

    samples,agglomeration could be attributed to viscous silicate melts formed from reaction of inorganic alkalineand alkali earth species with silica from the bed particles. A mathematical model that addresses the defluidization behavior of alkali-rich samples was developed based on the experiments performed...... and calcium, which may form viscous melts that adhere on the surface of the colliding bed particles and bind them to form agglomerates. In this paper, studies were made to understand the behavior of inorganic elements (mainly K, Si and Ca) on agglomeration and de-fluidization of alkali rich bed...... in the bench-scale fluidized bed reactor as well as on results from literature. The model was then used topredict the de-fluidization behavior of alkali-rich bed material in a large-scale LTCFB gasifier....

  15. High temperature experiment for accelerator inertial fusion

    International Nuclear Information System (INIS)

    Lee, E.P.

    1985-01-01

    The High Temperature Experiment (HTE) is intended to produce temperatures of 50-100 eV in solid density targets driven by heavy ion beams from a multiple beam induction linac. The fundamental variables (particle species, energy number of beamlets, current and pulse length) must be fixed to achieve the temperature at minimum cost, subject to criteria of technical feasibility and relevance to the development of a Fusion Driver. The conceptual design begins with an assumed (radiation-limited) target temperature and uses limitations due to particle range, beamlet perveance, and target disassembly to bound the allowable values of mass number (A) and energy (E). An accelerator model is then applied to determine the minimum length accelerator, which is a guide to total cost. The accelerator model takes into account limits on transportable charge, maximum gradient, core mass per linear meter, and head-to-tail momentum variation within a pulse

  16. High temperature reactors for cogeneration applications

    Energy Technology Data Exchange (ETDEWEB)

    Verfondern, Karl [Forschungszentrum Juelich (Germany). IEK-6; Allelein, Hans-Josef [Forschungszentrum Juelich (Germany). IEK-6; RWTH Aachen (Germany). Lehrstuhl fuer Reaktorsicherheit und -technik (LRST)

    2016-05-15

    There is a large potential for nuclear energy also in the non-electric heat market. Many industrial sectors have a high demand for process heat and steam at various levels of temperature and pressure to be provided for desalination of seawater, district heating, or chemical processes. The future generation of nuclear plants will be capable to enter the wide field of cogeneration of heat and power (CHP), to reduce waste heat and to increase efficiency. This requires an adjustment to multiple needs of the customers in terms of size and application. All Generation-IV concepts proposed are designed for coolant outlet temperatures above 500 C, which allow applications in the low and medium temperature range. A VHTR would even be able to cover the whole temperature range up to approx. 1 000 C.

  17. High-Temperature Shape Memory Polymers

    Science.gov (United States)

    Yoonessi, Mitra; Weiss, Robert A.

    2012-01-01

    physical conformation changes when exposed to an external stimulus, such as a change in temperature. Such materials have a permanent shape, but can be reshaped above a critical temperature and fixed into a temporary shape when cooled under stress to below the critical temperature. When reheated above the critical temperature (Tc, also sometimes called the triggering or switching temperature), the materials revert to the permanent shape. The current innovation involves a chemically treated (sulfonated, carboxylated, phosphonated, or other polar function group), high-temperature, semicrystalline thermoplastic poly(ether ether ketone) (Tg .140 C, Tm = 340 C) mix containing organometallic complexes (Zn++, Li+, or other metal, ammonium, or phosphonium salts), or high-temperature ionic liquids (e.g. hexafluorosilicate salt with 1-propyl-3- methyl imidazolium, Tm = 210 C) to form a network where dipolar or ionic interactions between the polymer and the low-molecular-weight or inorganic compound forms a complex that provides a physical crosslink. Hereafter, these compounds will be referred to as "additives". The polymer is semicrystalline, and the high-melt-point crystals provide a temporary crosslink that acts as a permanent crosslink just so long as the melting temperature is not exceeded. In this example case, the melting point is .340 C, and the shape memory critical temperature is between 150 and 250 C. PEEK is an engineering thermoplastic with a high Young fs modulus, nominally 3.6 GPa. An important aspect of the invention is the control of the PEEK functionalization (in this example, the sulfonation degree), and the thermal properties (i.e. melting point) of the additive, which determines the switching temperature. Because the compound is thermoplastic, it can be formed into the "permanent" shape by conventional plastics processing operations. In addition, the compound may be covalently cross - linked after forming the permanent shape by S-PEEK by applying ionizing

  18. HTGR fuel behavior at very high temperature

    International Nuclear Information System (INIS)

    Kashimura, Satoru; Ogawa, Touru; Fukuda, Kousaku; Iwamoto, Kazumi

    1986-03-01

    Fuel behavior at very high temperature simulating abnormal transient of the reactor operation and accidents have been investigated on TRISO coating LEU oxide particle fuels at JAERI. The test simulating the abnormal transient was carried out by irradiation of loose coated particles above 1600 deg C. The irradiation test indicated that particle failure was principally caused by kernel migration. For simulation of the core heat-up accident, two experiments of out-of-pile heating were made. Survival temperature limits were measured and fuel performance at very high temperature were investigated by the heatings. Study on the fuel behavior under reactivity initiated accident was made by NSRR(Nuclear Safety Research Reactor) pulse irradiation, where maximum temperature was higher than 2800 deg C. It was found in the pulse irradiation experiments that the coated particles incorporated in the compacts did not so severely fail unlike the loose coated particles at ultra high temperature above 2800 deg C. In the former particles UO 2 material at the center of the kernel vaporized, leaving a spherical void. (author)

  19. Positron annihilation studies on high temperature superconductors

    International Nuclear Information System (INIS)

    Sundar, C.S.; Bharathi, A.

    1991-01-01

    The results of positron annihilation measurements as a function of temperature, across Tc, in a variety of high temperature superconductors such as Y-Ba-Cu-O (Y1237), Y-Ba-Cu-O (Y1248), Bi-Sr-Ca-Cu-O, Tl-Ba-Ca-Cu-O, Ba-K-Bi-O and Nd-Ce-Cu-O are presented. It is shown that the variation of annihilation parameters in the superconducting state is correlated with the diposition of the positron density distribution with respect to the superconducting CuO planes. An increase in positron lifetime is observed below Tc when the positrons probe the CuO planes whereas a decrease in lifetime is observed when the positron density overlaps predominantly with the apical oxygen atom. With this correlation, the different temperature variation of annihilation parameters, seen in the various high temperature superconductors, is understood in terms of a local charge transfer from the planar oxygen atom to the apical oxygen atom. The significance of these results in the context of various theoretical models of high temperature superconductivity is discussed. In addition, the application of positron annihilation spectroscopy to the study of oxygen defects in the Y-Ba-Cu-O, Bi-Sr-Ca-Cu-O and Nd-Ce-Cu-O is presented. (author). 53 refs., 17 figs., 2 tabs

  20. Bimodular high temperature planar oxygen gas sensor

    Directory of Open Access Journals (Sweden)

    Xiangcheng eSun

    2014-08-01

    Full Text Available A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs thin film coated yttria-stabilized zirconia (YSZ substrate. The thin film was prepared by radio frequency (r.f. magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO nanoparticles film was characterized by atomic force microscopy (AFM and scanning electron microscopy (SEM. X-ray diffraction (XRD patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500 °C, 600 °C and 800 °C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors.

  1. Pt-catalyzed ozonation of aqueous phenol solution using high-gravity rotating packed bed

    International Nuclear Information System (INIS)

    Chang, Chia-Chi; Chiu, Chun-Yu; Chang, Ching-Yuan; Chang, Chiung-Fen; Chen, Yi-Hung; Ji, Dar-Ren; Tseng, Jyi-Yeong; Yu, Yue-Hwa

    2009-01-01

    In this study, a high-gravity rotating packed bed (HGRPB or HG) was used as a catalytic ozonation (Cat-OZ) reactor to decompose phenol. The operation of HGRPB system was carried out in a semi-batch apparatus which combines two major parts, namely the rotating packed bed (RPB) and photo-reactor (PR). The high rotating speed of RPB can give a high volumetric gas-liquid mass transfer coefficient with one or two orders of magnitude higher than those in the conventional packed beds. The platinum-containing catalyst (Dash 220N, Pt/γ-Al 2 O 3 ) and activated alumina (γ-Al 2 O 3 ) were packed in the RPB respectively to adsorb molecular ozone and the target pollutant of phenol on the surface to catalyze the oxidation of phenol. An ultra violet (UV) lamp (applicable wavelength λ = 200-280 nm) was installed in the PR to enhance the self-decomposition of molecular ozone in water to form high reactive radical species. Different combinations of advanced oxidation processes (AOPs) with the HGRPB for the degradation of phenol were tested. These included high-gravity OZ (HG-OZ), HG catalytic OZ (HG-Cat-OZ), HG photolysis OZ (HG-UV-OZ) and HG-Cat-OZ with UV (HG-Cat-UV-OZ). The decomposition efficiency of total organic compound (η TOC ) of HG-UV-OZ with power of UV (P UV ) of 16 W is 54% at applied dosage of ozone per volume sample m A,in = 1200 mg L -1 (reaction time t = 20 min), while that of HG-OZ without the UV irradiation is 24%. After 80 min oxidation (m A,in = 4800 mg L -1 ), the η TOC of HG-UV-OZ is as high as 94% compared to 82% of HG-OZ process. The values of η TOC for HG-Cat-OZ process with m S = 42 g are 56% and 87% at m A,in = 1200 and 4800 mg L -1 , respectively. By increasing the catalyst mass to 77 g, the η TOC for the HG-Cat-OZ process reaches 71% and 90% at m A,in = 1200 and 4800 mg L -1 , respectively. The introduction of Pt/γ-Al 2 O 3 as well as UV irradiation in the HG-OZ process can enhance the η TOC of phenol significantly, while γ-Al 2 O 3 exhibits

  2. Effect of process temperature on morphology of CNTs grown in a vertically fluidized bed reactor with Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Shukrullah, Shazia, E-mail: zshukrullah@gmail.com; Mohamed, Norani Muti, E-mail: noranimuti-mohamed@petronas.com.my; Shaharun, Maizatul Shima, E-mail: maizats@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    Carbon nanotubes (CNTs) are one of the most researched materials due to their exceptional mechanical and electrical properties. Among the various techniques, catalytic chemical vapor deposition in a fluidized bed reactor is the most promising technique for bulk production of CNTs. To meet the demand of good quality along with the bulk production of CNTs, the effect of reaction temperature on the micro structures, morphology, diameter, quality and quantity of CNTs was investigated in these studies. CNTs were synthesized at process temperature ranging from 700-850°C by catalytic decomposition of C{sub 2}H{sub 4} on Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst a vertical fluidized bed reactor. The microstructures of the grown CNTs at different reaction temperatures were investigated by using scanning electron microscope. The results of this study depicted a positive correlation between the average diameter of CNTs and reaction temperature. Narrow diameters (35∼40 nm) of CNTs with fewer defects were found at the low and mild temperatures, in particular 800°C. At this temperature, a dynamic equilibrium between the rate of C{sub 2}H{sub 4} decomposition and CNTs quantity was found due to maximum carbon diffusion over catalyst. The CNTs produced with Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst wer e also exhibiting high quality with relatively small mean outer diameter and fewer surface defects.

  3. High temperature and high pressure equation of state of gold

    International Nuclear Information System (INIS)

    Matsui, Masanori

    2010-01-01

    High-temperature and high-pressure equation of state (EOS) of Au has been developed using measured data from shock compression up to 240 GPa, volume thermal expansion between 100 and 1300 K and 0 GPa, and temperature dependence of bulk modulus at 0 GPa from ultrasonic measurements. The lattice thermal pressures at high temperatures have been estimated based on the Mie-Grueneisen-Debye type treatment with the Vinet isothermal EOS. The contribution of electronic thermal pressure at high temperatures, which is relatively insignificant for Au, has also been included here. The optimized EOS parameters are K' 0T = 6.0 and q = 1.6 with fixed K 0T = 167 GPa, γ 0 = 2.97, and Θ 0 = 170 K from previous investigations. We propose the present EOS to be used as a reliable pressure standard for static experiments up to 3000K and 300 GPa.

  4. High Temperature Materials Interim Data Qualification Report

    International Nuclear Information System (INIS)

    Lybeck, Nancy

    2010-01-01

    Projects for the very high temperature reactor (VHTR) Technology Development Office provide data in support of Nuclear Regulatory Commission licensing of the VHTR. Fuel and materials to be used in the reactor are tested and characterized to quantify performance in high temperature and high fluence environments. The VHTR program has established the NGNP Data Management and Analysis System (NDMAS) to ensure that VHTR data are qualified for use, stored in a readily accessible electronic form, and analyzed to extract useful results. This document focuses on the first NDMAS objective. It describes the High Temperature Materials characterization data stream, the processing of these data within NDMAS, and reports the interim FY2010 qualification status of the data. Data qualification activities within NDMAS for specific types of data are determined by the data qualification category assigned by the data generator. The High Temperature Materials data are being collected under NQA-1 guidelines, and will be qualified data. For NQA-1 qualified data, the qualification activities include: (1) capture testing, to confirm that the data stored within NDMAS are identical to the raw data supplied, (2) accuracy testing to confirm that the data are an accurate representation of the system or object being measured, and (3) documenting that the data were collected under an NQA-1 or equivalent Quality Assurance program. Currently, data from two test series within the High Temperature Materials data stream have been entered into the NDMAS vault: (1) Tensile Tests for Sm (i.e., Allowable Stress) Confirmatory Testing - 1,403,994 records have been inserted into the NDMAS database. Capture testing is in process. (2) Creep-Fatigue Testing to Support Determination of Creep-Fatigue Interaction Diagram - 918,854 records have been processed and inserted into the NDMAS database. Capture testing is in process.

  5. Dynamics of Gauge Fields at High Temperature

    NARCIS (Netherlands)

    Nauta, B.J.

    2000-01-01

    An effective description of dynamical Bose fields is provided by the classical (high-temperature) limit of thermal field theory. The main subject of this thesis is to improve the ensuing classical field theory, that is, to include the dominant quantum corrections and to add counter terms for the

  6. High temperature oxidation resistant cermet compositions

    Science.gov (United States)

    Phillips, W. M. (Inventor)

    1976-01-01

    Cermet compositions are designed to provide high temperature resistant refractory coatings on stainless steel or molybdenum substrates. A ceramic mixture of chromium oxide and aluminum oxide form a coating of chromium oxide as an oxidation barrier around the metal particles, to provide oxidation resistance for the metal particles.

  7. Dense high-temperature plasma transport processes

    International Nuclear Information System (INIS)

    Giniyatova, Sh.G.

    2002-01-01

    In this work the transport processes in dense high-temperature semiclassical plasma are studied on the base of the kinetic equation, where the semiclassical potential was used, in its collision integral. The coefficient of plasma electrical conductivity, viscosity and thermal conductivity were received. There were compared with the other authors' results. The Grad's method was used obtaining of viscosity and thermal coefficients. (author)

  8. Nuclear and quark matter at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Biro, Tamas S. [H.A.S. Wigner Research Centre for Physics, Budapest (Hungary); Jakovac, Antal [Roland Eotvos University, Budapest (Hungary); Schram, Zsolt [University of Debrecen, Institute for Theoretical Physics, Debrecen (Hungary)

    2017-03-15

    We review important ideas on nuclear and quark matter description on the basis of high-temperature field theory concepts, like resummation, dimensional reduction, interaction scale separation and spectral function modification in media. Statistical and thermodynamical concepts are spotted in the light of these methods concentrating on the -partially still open- problems of the hadronization process. (orig.)

  9. The discovery of high temperature superconductivity

    International Nuclear Information System (INIS)

    Muller, K. A.; Bednorz, J.G.

    1988-01-01

    This article recalls the different stages which led to the display of high temperature superconductivity for Ba, La, Cu, O and the following avalanche of discoveries for other oxides; the numerous theoretical models which tentatively explain the current experimental results are also reviewed. 30 refs

  10. The discovery of high temperature superconductivity

    International Nuclear Information System (INIS)

    Muller, K.A.; Bednorz, J.G.

    1988-01-01

    This article recalls the different stages which led to the display of high temperature superconductivity for Ba La Cu O, and the following avalanche of discoveries for other oxides; the numerous theoretical models which tentatively explain the current experimental results are also reviewed [fr

  11. High temperature applications of nuclear energy

    International Nuclear Information System (INIS)

    1994-08-01

    The meeting was organized to review industry/user needs designs, status of technology and the associated economics for high temperature applications. It was attended by approximately 100 participants from nine countries. The participants presented 17 papers. A separate abstract was prepared for each of these papers. Refs, figs and tabs

  12. Potential applications of high temperature helium

    International Nuclear Information System (INIS)

    Schleicher, R.W. Jr.; Kennedy, A.J.

    1992-09-01

    This paper discusses the DOE MHTGR-SC program's recent activity to improve the economics of the MHTGR without sacrificing safety performance and two potential applications of high temperature helium, the MHTGR gas turbine plant and a process heat application for methanol production from coal

  13. HYFIRE: fusion-high temperature electrolysis system

    International Nuclear Information System (INIS)

    Fillo, J.A.; Powell, J.R.; Steinberg, M.; Benenati, R.; Dang, V.D.; Horn, F.; Isaacs, H.; Lazareth, O.; Makowitz, H.; Usher, J.

    1980-01-01

    The Brookhaven National Laboratory (BNL) is carrying out a comprehensive conceptual design study called HYFIRE of a commercial fusion Tokamak reactor, high-temperature electrolysis system. The study is placing particular emphasis on the adaptability of the STARFIRE power reactor to a synfuel application. The HYFIRE blanket must perform three functions: (a) provide high-temperature (approx. 1400 0 C) process steam at moderate pressures (in the range of 10 to 30 atm) to the high-temperature electrolysis (HTE) units; (b) provide high-temperature (approx. 700 to 800 0 C) heat to a thermal power cycle for generation of electricity to the HTE units; and (c) breed enough tritium to sustain the D-T fuel cycle. In addition to thermal energy for the decomposition of steam into its constitutents, H 2 and O 2 , electrical input is required. Power cycle efficiencies of approx. 40% require He cooling for steam superheat. Fourteen hundred degree steam coupled with 40% power cycle efficiency results in a process efficiency (conversion of fusion energy to hydrogen chemical energy) of 50%

  14. High Temperature Corrosion in Biomass Incineration Plants

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Maahn, Ernst emanuel; Gotthjælp, K.

    1997-01-01

    The aim of the project is to study the role of ash deposits in high temperature corrosion of superheater materials in biomass and refuse fire combined heat and power plants. The project has included the two main activities: a) A chemical characterisation of ash deposits collected from a major...

  15. Thermoelastic properties of minerals at high temperature

    Indian Academy of Sciences (India)

    In our present study, we have investigated the thermophysical properties of two minerals (pyrope-rich garnet and MgAl2O4) under high temperatures and calculated the second-order elastic constant () and bulk modulus (T) of the above minerals, in two cases first by taking Anderson–Gruneisen parameter (T) as ...

  16. Theory of high temperature plasmas. Final report

    International Nuclear Information System (INIS)

    Davidson, R.C.; Liu, C.S.

    1977-01-01

    This is a report on the technical progress in our analytic studies of high-temperature fusion plasmas. We also emphasize that the research summarized here makes extensive use of computational methods and therefore forms a strong interface with our numerical modeling program which is discussed later in the report

  17. Combined photolysis and catalytic ozonation of dimethyl phthalate in a high-gravity rotating packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.-C. [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 106, Taiwan (China); Chiu, C.-Y. [Department of Cosmetic Science and Application, Lan-Yang Institute of Technology, I-Lan 261, Taiwan (China); Chang, C.-Y. [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 106, Taiwan (China)], E-mail: cychang3@ntu.edu.tw; Chang, C.-F. [Department of Environmental Science and Engineering, Tunghai University, Taichung 407, Taiwan (China); Chen, Y.-H. [Department of Chemical and Material Engineering, National Kaohsiung University of Applied Science, Kaohsiung City 807, Taiwan (China); Ji, D.-R.; Yu, Y.-H.; Chiang, P.-C. [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 106, Taiwan (China)

    2009-01-15

    In this study, a high-gravity rotating packed bed (HGRPB) was used as a catalytic ozonation reactor to decompose dimethyl phthalate (DMP), an endocrine disrupting chemical commonly encountered. The HGRPB is an effective gas-liquid mixing equipment which can enhance the ozone mass transfer coefficient. Platinum-containing catalyst (Pt/-Al{sub 2}O{sub 3}) of Dash 220N and ultra violet (UV) lamp were combined in the high-gravity ozonation (HG-OZ) system to enhance the self-decomposition of molecular ozone in liquid to form highly reactive radical species. Different combinations of HG-OZ with Dash 220N and UV for the degradation of DMP were tested. These include HG-OZ, HG catalytic OZ (HG-Pt-OZ), HG photolysis OZ (HG-UV-OZ) and HG-UV-Pt-OZ. The result indicated that all the above four ozonation processes result in significant decomposition of DMP and mineralization of total organic carbon (TOC) at the applied ozone dosage per volume of liquid sample of 1.2 g L{sup -1}. The UV and Pt/{gamma}-Al{sub 2}O{sub 3} combined in HG-OZ can enhance the TOC mineralization efficiency ({eta}{sub TOC}) to 56% (via HG-UV-OZ) and 57% (via HG-Pt-OZ), respectively, while only 45% with ozone only. The process of HG-UV-Pt-OZ offers the highest {eta}{sub TOC} of about 68%.

  18. Nuclear shell effects at high temperatures

    International Nuclear Information System (INIS)

    Davidson, N.J.; Miller, H.G.

    1993-01-01

    In discussing the disappearance of nuclear shell effects at high temperatures, it is important to distinguish between the ''smearing out'' of the single-particle spectrum with increasing temperature and the vanishing of shell related structures in many-body quantities such as the excitation energy per nucleon. We propose a semiempirical method to obtain an upper bound on the temperature required to smooth the single-particle spectrum, and point out that shell effects in many-body parameters may persist above this temperature. We find that the temperature required to smear out the single-particle spectrum is approximately 1 MeV for heavy nuclei (A approx-gt 150) and about 3--4 MeV for light nuclei (A approx-lt 50), in reasonable agreement with the estimate of 41/πA 1/3 obtained from calculations with harmonic oscillator potentials. These temperatures correspond to many-body excitation energies of approximately 20 and 60 MeV, respectively

  19. High temperature reactor safety and environment

    International Nuclear Information System (INIS)

    Brisbois, J.; Charles, J.

    1975-01-01

    High-temperature reactors are endowed with favorable safety and environmental factors resulting from inherent design, main-component safety margins, and conventional safety systems. The combination of such characteristics, along with high yields, prove in addition, that such reactors are plagued with few problems, can be installed near users, and broaden the recourse to specific power, therefore fitting well within a natural environment [fr

  20. High-pressure-high-temperature treatment of natural diamonds

    CERN Document Server

    Royen, J V

    2002-01-01

    The results are reported of high-pressure-high-temperature (HPHT) treatment experiments on natural diamonds of different origins and with different impurity contents. The diamonds are annealed in a temperature range up to 2000 sup o C at stabilizing pressures up to 7 GPa. The evolution is studied of different defects in the diamond crystal lattice. The influence of substitutional nitrogen atoms, plastic deformation and the combination of these is discussed. Diamonds are characterized at room and liquid nitrogen temperature using UV-visible spectrophotometry, Fourier transform infrared spectrophotometry and photoluminescence spectrometry. The economic implications of diamond HPHT treatments are discussed.

  1. New Waste Calciner High Temperature Operation

    International Nuclear Information System (INIS)

    Swenson, M.C.

    2000-01-01

    A new Calciner flowsheet has been developed to process the sodium-bearing waste (SBW) in the INTEC Tank Farm. The new flowsheet increases the normal Calciner operating temperature from 500 C to 600 C. At the elevated temperature, sodium in the waste forms stable aluminates, instead of nitrates that melt at calcining temperatures. From March through May 2000, the new high-temperature flowsheet was tested in the New Waste Calcining Facility (NWCF) Calciner. Specific test criteria for various Calciner systems (feed, fuel, quench, off-gas, etc.) were established to evaluate the long-term operability of the high-temperature flowsheet. This report compares in detail the Calciner process data with the test criteria. The Calciner systems met or exceeded all test criteria. The new flowsheet is a visible, long-term method of calcining SBW. Implementation of the flowsheet will significantly increase the calcining rate of SBW and reduce the amount of calcine produced by reducing the amount of chemical additives to the Calciner. This will help meet the future waste processing milestones and regulatory needs such as emptying the Tank Farm

  2. A high temperature reactor for ship propulsion

    International Nuclear Information System (INIS)

    Lobet, P.; Seigel, R.; Thompson, A.C.; Beadnell, R.M.; Beeley, P.A.

    2002-01-01

    The initial thermal hydraulic and physics design of a high temperature gas cooled reactor for ship propulsion is described. The choice of thermodynamic cycle and thermal power is made to suit the marine application. Several configurations of a Helium cooled, Graphite moderated reactor are then analysed using the WIMS and MONK codes from AEA Technology. Two geometries of fuel elements formed using micro spheres in prismatic blocks, and various arrangements of control rods and poison rods are examined. Reactivity calculations through life are made and a pattern of rod insertion to flatten the flux is proposed and analysed. Thermal hydraulic calculations are made to find maximum fuel temperature under high power with optimized flow distribution. Maximum temperature after loss of flow and temperatures in the reactor vessel are also computed. The temperatures are significantly below the known limits for the type of fuel proposed. It is concluded that the reactor can provide the required power and lifetime between refueling within likely space and weight constraints. (author)

  3. High temperature superconductors applications in telecommunications

    International Nuclear Information System (INIS)

    Kumar, A.A.; Li, J.; Zhang, M.F.

    1994-01-01

    The purpose of this paper is twofold: to discuss high temperature superconductors with specific reference to their employment in telecommunications applications; and to discuss a few of the limitations of the normally employed two-fluid model. While the debate on the actual usage of high temperature superconductors in the design of electronic and telecommunications devices-obvious advantages versus practical difficulties-needs to be settled in the near future, it is of great interest to investigate the parameters and the assumptions that will be employed in such designs. This paper deals with the issue of providing the microwave design engineer with performance data for such superconducting waveguides. The values of conductivity and surface resistance, which are the primary determining factors of a waveguide performance, are computed based on the two-fluid model. A comparison between two models-a theoretical one in terms of microscopic parameters (termed Model A) and an experimental fit in terms of macroscopic parameters (termed Model B)-shows the limitations and the resulting ambiguities of the two-fluid model at high frequencies and at temperatures close to the transition temperature. The validity of the two-fluid model is then discussed. Our preliminary results show that the electrical transport description in the normal and superconducting phases as they are formulated in the two-fluid model needs to be modified to incorporate the new and special features of high temperature superconductors. Parameters describing the waveguide performance-conductivity, surface resistance and attenuation constant-will be computed. Potential applications in communications networks and large scale integrated circuits will be discussed. Some of the ongoing work will be reported. In particular, a brief proposal is made to investigate of the effects of electromagnetic interference and the concomitant notion of electromagnetic compatibility (EMI/EMC) of high T c superconductors

  4. High temperature superconductors applications in telecommunications

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A.A.; Li, J.; Zhang, M.F. [Prairie View A& M Univ., Texas (United States)

    1994-12-31

    The purpose of this paper is twofold: to discuss high temperature superconductors with specific reference to their employment in telecommunications applications; and to discuss a few of the limitations of the normally employed two-fluid model. While the debate on the actual usage of high temperature superconductors in the design of electronic and telecommunications devices-obvious advantages versus practical difficulties-needs to be settled in the near future, it is of great interest to investigate the parameters and the assumptions that will be employed in such designs. This paper deals with the issue of providing the microwave design engineer with performance data for such superconducting waveguides. The values of conductivity and surface resistance, which are the primary determining factors of a waveguide performance, are computed based on the two-fluid model. A comparison between two models-a theoretical one in terms of microscopic parameters (termed Model A) and an experimental fit in terms of macroscopic parameters (termed Model B)-shows the limitations and the resulting ambiguities of the two-fluid model at high frequencies and at temperatures close to the transition temperature. The validity of the two-fluid model is then discussed. Our preliminary results show that the electrical transport description in the normal and superconducting phases as they are formulated in the two-fluid model needs to be modified to incorporate the new and special features of high temperature superconductors. Parameters describing the waveguide performance-conductivity, surface resistance and attenuation constant-will be computed. Potential applications in communications networks and large scale integrated circuits will be discussed. Some of the ongoing work will be reported. In particular, a brief proposal is made to investigate of the effects of electromagnetic interference and the concomitant notion of electromagnetic compatibility (EMI/EMC) of high T{sub c} superconductors.

  5. Sodium immersible high temperature microphone design description

    International Nuclear Information System (INIS)

    Gavin, A.P.; Anderson, T.T.; Janicek, J.J.

    1975-02-01

    Argonne National Laboratory has developed a rugged high-temperature (HT) microphone for use as a sodium-immersed acoustic monitor in Liquid Metal Fast Breeder Reactors (LMFBRs). Microphones of this design have been extensively tested in room temperature water, in air up to 1200 0 F, and in sodium up to 1200 0 F. They have been successfully installed and employed as acoustic monitors in several operating liquid metal systems. The design, construction sequence, calibration, and testing of these microphones are described. 6 references. (U.S.)

  6. High temperature aircraft research furnace facilities

    Science.gov (United States)

    Smith, James E., Jr.; Cashon, John L.

    1992-01-01

    Focus is on the design, fabrication, and development of the High Temperature Aircraft Research Furnace Facilities (HTARFF). The HTARFF was developed to process electrically conductive materials with high melting points in a low gravity environment. The basic principle of operation is to accurately translate a high temperature arc-plasma gas front as it orbits around a cylindrical sample, thereby making it possible to precisely traverse the entire surface of a sample. The furnace utilizes the gas-tungsten-arc-welding (GTAW) process, also commonly referred to as Tungsten-Inert-Gas (TIG). The HTARFF was developed to further research efforts in the areas of directional solidification, float-zone processing, welding in a low-gravity environment, and segregation effects in metals. The furnace is intended for use aboard the NASA-JSC Reduced Gravity Program KC-135A Aircraft.

  7. High-Temperature Graphite/Phenolic Composite

    Science.gov (United States)

    Seal, Ellis C.; Bodepudi, Venu P.; Biggs, Robert W., Jr.; Cranston, John A.

    1995-01-01

    Graphite-fiber/phenolic-resin composite material retains relatively high strength and modulus of elasticity at temperatures as high as 1,000 degrees F. Costs only 5 to 20 percent as much as refractory materials. Fabrication composite includes curing process in which application of full autoclave pressure delayed until after phenolic resin gels. Curing process allows moisture to escape, so when composite subsequently heated in service, much less expansion of absorbed moisture and much less tendency toward delamination. Developed for nose cone of external fuel tank of Space Shuttle. Other potential aerospace applications for material include leading edges, parts of nozzles, parts of aircraft engines, and heat shields. Terrestrial and aerospace applications include structural firewalls and secondary structures in aircraft, spacecraft, and ships. Modified curing process adapted to composites of phenolic with other fiber reinforcements like glass or quartz. Useful as high-temperature circuit boards and electrical insulators.

  8. The metallurgy of high temperature alloys

    Science.gov (United States)

    Tien, J. K.; Purushothaman, S.

    1976-01-01

    Nickel-base, cobalt-base, and high nickel and chromium iron-base alloys are dissected, and their microstructural and chemical components are assessed with respect to the various functions expected of high temperature structural materials. These functions include the maintenance of mechanical integrity over the strain-rate spectrum from creep resistance through fatigue crack growth resistance, and such alloy stability expectations as microstructural coarsening resistance, phase instability resistance and oxidation and corrosion resistance. Special attention will be given to the perennial conflict and trade-off between strength, ductility and corrosion and oxidation resistance. The newest developments in the constitution of high temperature alloys will also be discussed, including aspects relating to materials conservation.

  9. High temperature sensors for exhaust diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Svenningstorp, Henrik

    2000-07-01

    One of the largest problems that we will have to deal with on this planet this millennium is to stop the pollution of our environment. In many of the ongoing works to reduce toxic emissions, gas sensors capable of enduring rough environments and high temperatures, would be a great tool. The different applications where sensors like this would be useful vary between everything from online measurement in the paper industry and food industry to measurement in the exhaust pipe of a car. In my project we have tested Schottky diodes and MlSiCFET sensor as gas sensors operating at high temperatures. The measurement condition in the exhaust pipe of a car is extremely tough, not only is the temperature high and the different gases quite harmful, there are also a lot of particles that can affect the sensors in an undesirable way. In my project we have been testing Schottky diodes and MlSiCFET sensors based on SiC as high temperature sensors, both in the laboratory with simulated exhaust and after a real engine. In this thesis we conclude that these sensors can work in the hostile environment of an engines exhaust. It is shown that when measuring in a gas mixture with a fixed I below one, where the I-value is controlled by the O{sub 2} concentration, a sensor with a catalytic gate metal as sensitive material respond more to the increased O{sub 2} concentration than the increased HC concentration when varying the two correspondingly. A number of different sensors have been tested in simulated exhaust towards NO{sub x}. It was shown that resistivity changes in the thin gate metal influenced the gas response. Tests have been performed where sensors were a part of a SCR system with promising results concerning NH{sub 3} sensitivity. With a working temperature of 300 deg C there is no contamination of the metal surface.

  10. Treatment of thin stillage in a high-rate anaerobic fluidized bed bioreactor (AFBR).

    Science.gov (United States)

    Andalib, Mehran; Hafez, Hisham; Elbeshbishy, Elsayed; Nakhla, George; Zhu, Jesse

    2012-10-01

    The primary objective of this work was to investigate the treatability of thin stillage as a by-product of bioethanol production plants using an anaerobic fluidized bed bioreactor (AFBR) employing zeolite with average diameter of (d(m)) of 425-610 μm and specific surface area (SSA) of 26.5m(2)/g as the carrier media. Despite the very high strength of thin stillage with chemical oxygen demand of 130,000 mg TCOD/L and suspended solids of 47,000 mg TSS/L, the AFBR showed up to 88% TCOD and 78% TSS removal at very high organic and solids loading rates (OLR and SLR) of 29 kg COD/m(3)d and 10.5 kg TSS/m(3)d respectively and hydraulic retention time (HRT) of 3.5 days. Methane production rates of up to 160 L/d at the steady state equivalent to 40 L(CH4)/L(thin stillage)d and biogas production rate per reactor volume of 15.8L(gas)/L(reactor)d were achieved. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. High-resolution ice thickness and bed topography of a land-terminating section of the Greenland Ice Sheet

    DEFF Research Database (Denmark)

    Lindbäck, K.; Pettersson, R.; Doyle, S. H.

    2014-01-01

    We present ice thickness and bed topography maps with high spatial resolution (250 to 500 m) of a and-terminating section of the Greenland Ice Sheet derived from combined ground-based and airborne radar surveys. The data have a total area of ~12000 km2 and cover the whole ablation area of the out...

  12. Temperature profile in a fix-bed reactor and with cylindrical geometry by the method of orthogonal collocation

    International Nuclear Information System (INIS)

    Basta, C.

    1982-01-01

    Using the method of orthogonal colocation the boundary problem for a fix bed with cylindrical geometry was solved. The axial disposal term was despicable and the results were compared with those the explicit finite difference method. (E.G.) [pt

  13. Thermoelectric properties by high temperature annealing

    Science.gov (United States)

    Ren, Zhifeng (Inventor); Chen, Gang (Inventor); Kumar, Shankar (Inventor); Lee, Hohyun (Inventor)

    2009-01-01

    The present invention generally provides methods of improving thermoelectric properties of alloys by subjecting them to one or more high temperature annealing steps, performed at temperatures at which the alloys exhibit a mixed solid/liquid phase, followed by cooling steps. For example, in one aspect, such a method of the invention can include subjecting an alloy sample to a temperature that is sufficiently elevated to cause partial melting of at least some of the grains. The sample can then be cooled so as to solidify the melted grain portions such that each solidified grain portion exhibits an average chemical composition, characterized by a relative concentration of elements forming the alloy, that is different than that of the remainder of the grain.

  14. High temperature superconductivity and cold fusion

    International Nuclear Information System (INIS)

    Rabinowitz, M.

    1990-01-01

    There are numerous historical and scientific parallels between high temperature superconductivity (HTSC) and the newly emerging field of cold fusion (CF). Just as the charge carrier effective mass plays an important role in SC, the deuteron effective mass may play a vital role in CF. A new theory including effects of proximity, electron shielding, and decreased effective mass of the fusing nuclei can account for the reported CF results. A quantum-gas model that covers the range from low temperature to superhigh temperature SC indicates an increased T c with reduced dimensionality. A reduced dimensionality effect may also enhance CF. A relation is shown between CF and the significant cluster-impact fusion experiments

  15. Positron annihilation studies on high temperature superconductors

    International Nuclear Information System (INIS)

    Sundar, C.S.; Bharathi, A.

    1996-01-01

    A survey of the positron annihilation studies on high temperature superconductors (HTSC), with results drawn mainly from our work, is presented. These include results of the studies on the temperature dependence of positron lifetime across T c , which have been carried out in the whole gamut of oxide superconductors. These experimental results are discussed in conjunction with the results of theoretically calculated positron density distribution, and it is shown that the observed temperature dependence of lifetime is intimately linked to the probing of the Cu-O network by the positrons. Results on the investigation of oxygen defects, which play a crucial role in HTSC, are presented. The most significant contribution of positrons to HTSC relates to the investigation of Fermi surface and the results of these studies, drawn from literature, are indicated. Some of our recent results in other novel superconducting materials, viz., the fullerenes and borocarbides are also presented. (author). 69 refs., 15 figs

  16. High temperature ceramic-tubed reformer

    Science.gov (United States)

    Williams, Joseph J.; Rosenberg, Robert A.; McDonough, Lane J.

    1990-03-01

    The overall objective of the HiPHES project is to develop an advanced high-pressure heat exchanger for a convective steam/methane reformer. The HiPHES steam/methane reformer is a convective, shell and tube type, catalytic reactor. The use of ceramic tubes will allow reaction temperature higher than the current state-of-the-art outlet temperatures of about 1600 F using metal tubes. Higher reaction temperatures increase feedstock conversion to synthesis gas and reduce energy requirements compared to currently available radiant-box type reformers using metal tubes. Reforming of natural gas is the principal method used to produce synthesis gas (primarily hydrogen and carbon monoxide, H2 and CO) which is used to produce hydrogen (for refinery upgrading), methanol, as well as several other important materials. The HiPHES reformer development is an extension of Stone and Webster's efforts to develop a metal-tubed convective reformer integrated with a gas turbine cycle.

  17. Toroidal microinstability studies of high temperature tokamaks

    International Nuclear Information System (INIS)

    Rewoldt, G.; Tang, W.M.

    1989-07-01

    Results from comprehensive kinetic microinstability calculations are presented showing the effects of toroidicity on the ion temperature gradient mode and its relationship to the trapped-electron mode in high-temperature tokamak plasmas. The corresponding particle and energy fluxes have also been computed. It is found that, although drift-type microinstabilities persist over a wide range of values of the ion temperature gradient parameter η i ≡ (dlnT i /dr)/(dlnn i /dr), the characteristic features of the dominant mode are those of the η i -type instability when η i > η ic ∼1.2 to 1.4 and of the trapped-electron mode when η i ic . 16 refs., 7 figs

  18. High gradient magnetic separation versus expanded bed adsorption: a first principle comparison

    DEFF Research Database (Denmark)

    Hubbuch, Jürgen; Matthiesen, D.B.; Hobley, Timothy John

    2001-01-01

    A robust new adsorptive separation technique specifically designed for direct product capture from crude bioprocess feedstreams is introduced and compared with the current bench mark technique, expanded bed adsorption. The method employs product adsorption onto sub-micron sized non...

  19. High temperature deformation of silicon steel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Calvillo, Pablo, E-mail: pablo.rodriguez@ctm.com.es [CTM - Technologic Centre, Materials Technology Area, Manresa, Cataluna (Spain); Department of Materials Science and Metallurgical Engineering, Universidad Politecnica de Cataluna, Barcelona (Spain); Houbaert, Yvan, E-mail: Yvan.Houbaert@UGent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Petrov, Roumen, E-mail: Roumen.Petrov@ugent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Kestens, Leo, E-mail: Leo.kestens@ugent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Colas, Rafael, E-mail: rafael.colas@uanl.edu.mx [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia, Universidad Autonoma de Nuevo Leon (Mexico)

    2012-10-15

    The microstructure and texture development during high temperature plane strain compression of 2% in weight silicon steel was studied. The tests were carried out at a constant strain rate of 5 s{sup -1} with reductions of 25, 35 and 75% at temperatures varying from 800 to 1100 Degree-Sign C. The changes in microstructure and texture were studied by means of scanning electron microscopy and electron backscattered diffraction. The microstructure close to the surface of the samples was equiaxed, which is attributed to the shear caused by friction, whereas that at the centre of the specimens was made of a mixture of elongated and fine equiaxed grains, the last ones attributed to the action of dynamic recovery followed by recrystallization. It was found that the volume fraction of these equiaxed grains augmented as reduction and temperature increased; a 0.7 volume fraction was accomplished with a 75% reduction at 1100 Degree-Sign C. The texture of the equiaxed and elongated grains was found to vary with the increase of deformation and temperature, as the {gamma}-fibre tends to disappear and the {alpha}-fibre to increase towards the higher temperature range. -- Highlights: Black-Right-Pointing-Pointer The plastic deformation of a silicon containing steel is studied by plane strain compression. Black-Right-Pointing-Pointer Equiaxed and elongated grains develop in different regions of the sample due to recrystallization. Black-Right-Pointing-Pointer Texture, by EBSD, is revealed to be similar in either type of grains.

  20. High temperature deformation of silicon steel

    International Nuclear Information System (INIS)

    Rodríguez-Calvillo, Pablo; Houbaert, Yvan; Petrov, Roumen; Kestens, Leo; Colás, Rafael

    2012-01-01

    The microstructure and texture development during high temperature plane strain compression of 2% in weight silicon steel was studied. The tests were carried out at a constant strain rate of 5 s −1 with reductions of 25, 35 and 75% at temperatures varying from 800 to 1100 °C. The changes in microstructure and texture were studied by means of scanning electron microscopy and electron backscattered diffraction. The microstructure close to the surface of the samples was equiaxed, which is attributed to the shear caused by friction, whereas that at the centre of the specimens was made of a mixture of elongated and fine equiaxed grains, the last ones attributed to the action of dynamic recovery followed by recrystallization. It was found that the volume fraction of these equiaxed grains augmented as reduction and temperature increased; a 0.7 volume fraction was accomplished with a 75% reduction at 1100 °C. The texture of the equiaxed and elongated grains was found to vary with the increase of deformation and temperature, as the γ-fibre tends to disappear and the α-fibre to increase towards the higher temperature range. -- Highlights: ► The plastic deformation of a silicon containing steel is studied by plane strain compression. ► Equiaxed and elongated grains develop in different regions of the sample due to recrystallization. ► Texture, by EBSD, is revealed to be similar in either type of grains.

  1. Energy storage via high temperature superconductivity (SMES)

    Energy Technology Data Exchange (ETDEWEB)

    Mikkonen, R. [Tampere Univ. of Technology (Finland)

    1998-10-01

    The technology concerning high temperature superconductors (HTS) is matured to enabling different kind of prototype applications including SMES. Nowadays when speaking about HTS systems, attention is focused on the operating temperature of 20-30 K, where the critical current and flux density are fairly close to 4.2 K values. In addition by defining the ratio of the energy content of a novel HTS magnetic system and the required power to keep the system at the desired temperature, the optimum settles to the above mentioned temperature range. In the frame of these viewpoints a 5 kJ HTS SMES system has been designed and tested at Tampere University of Technology with a coil manufactured by American Superconductor (AMSC). The HTS magnet has inside and outside diameters of 252 mm and 317 mm, respectively and axial length of 66 mm. It operates at 160 A and carries a total of 160 kA-turns to store the required amount of energy. The effective magnetic inductance is 0.4 H and the peak axial field is 1.7 T. The magnet is cooled to the operating temperature of 20 K with a two stage Gifford-McMahon type cryocooler with a cooling power of 60 W at 77 K and 8 W at 20 K. The magnetic system has been demonstrated to compensate a short term loss of power of a sensitive consumer

  2. FLUIDIZED BED STEAM REFORMING MINERALIZATION FOR HIGH ORGANIC AND NITRATE WASTE STREAMS FOR THE GLOBAL NUCLEAR ENERGY PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C; Michael Williams, M

    2008-01-11

    Waste streams that may be generated by the Global Nuclear Energy Partnership (GNEP) Advanced Energy Initiative may contain significant quantities of organics (0-53 wt%) and/or nitrates (0-56 wt%). Decomposition of high nitrate streams requires reducing conditions, e.g. organic additives such as sugar or coal, to reduce the NO{sub x} in the off-gas to N{sub 2} to meet the Clean Air Act (CAA) standards during processing. Thus, organics will be present during waste form stabilization regardless of which GNEP processes are chosen, e.g. organics in the feed or organics for nitrate destruction. High organic containing wastes cannot be stabilized with the existing HLW Best Developed Available Technology (BDAT) which is HLW vitrification (HLVIT) unless the organics are removed by preprocessing. Alternative waste stabilization processes such as Fluidized Bed Steam Reforming (FBSR) operate at moderate temperatures (650-750 C) compared to vitrification (1150-1300 C). FBSR converts organics to CAA compliant gases, creates no secondary liquid waste streams, and creates a stable mineral waste form that is as durable as glass. For application to the high Cs-137 and Sr-90 containing GNEP waste streams a single phase mineralized Cs-mica phase was made by co-reacting illite clay and GNEP simulated waste. The Cs-mica accommodates up to 30% wt% Cs{sub 2}O and all the GNEP waste species, Ba, Sr, Rb including the Cs-137 transmutation to Ba-137. For reference, the cesium mineral pollucite (CsAlSi{sub 2}O{sub 6}), currently being studied for GNEP applications, can only be fabricated at {ge} 1000 C. Pollucite mineralization creates secondary aqueous waste streams and NO{sub x}. Pollucite is not tolerant of high concentrations of Ba, Sr or Rb and forces the divalent species into different mineral host phases. The pollucite can accommodate up to 33% wt% Cs{sub 2}O.

  3. Application of high temperature superconductors for fusion

    International Nuclear Information System (INIS)

    Fietz, W.H.; Heller, R.; Schlachter, S.I.; Goldacker, W.

    2011-01-01

    The use of High Temperature Superconductor (HTS) materials in future fusion machines can increase the efficiency drastically. For ITER, W7-X and JT-60SA the economic benefit of HTS current leads was recognized after a 70 kA HTS current lead demonstrator was designed, fabricated and successfully tested by Karlsruhe Institute of Technology (KIT, which is a merge of former Forschungszentrum Karlsruhe and University of Karlsruhe). For ITER, the Chinese Domestic Agency will provide the current leads as a part of the superconducting feeder system. KIT is in charge of design, construction and test of HTS current leads for W7-X and JT-60SA. For W7-X 14 current leads with a maximum current of 18.2 kA are required that are oriented with the room temperature end at the bottom. JT60-SA will need 26 current leads (20 leads - 20 kA and 6 leads - 25.7 kA) which are mounted in vertical, normal position. These current leads are based on BiSCCO HTS superconductors, demonstrating that HTS material is now state of the art for highly efficient current leads. With respect to future fusion reactors, it would be very promising to use HTS material not only in current leads but also in coils. This would allow a large increase of efficiency if the coils could be operated at temperatures ≥65 K. With such a high temperature it would be possible to omit the radiation shield of the coils, resulting in a less complex cryostat and a size reduction of the machine. In addition less refrigeration power is needed saving investment and operating costs. However, to come to an HTS fusion coil it is necessary to develop low ac loss HTS cables for currents well above 20 kA at high fields well above 10 T. The high field rules BiSCCO superconductors out at temperatures above 50 K, but RE-123 superconductors are promising. The development of a high current, high field RE-123 HTS fusion cable will not be targeted outside fusion community and has to be in the frame of a long term development programme for

  4. Computer code validation by high temperature chemistry

    International Nuclear Information System (INIS)

    Alexander, C.A.; Ogden, J.S.

    1988-01-01

    At least five of the computer codes utilized in analysis of severe fuel damage-type events are directly dependent upon or can be verified by high temperature chemistry. These codes are ORIGEN, CORSOR, CORCON, VICTORIA, and VANESA. With the exemption of CORCON and VANESA, it is necessary that verification experiments be performed on real irradiated fuel. For ORIGEN, the familiar knudsen effusion cell is the best choice and a small piece of known mass and known burn-up is selected and volatilized completely into the mass spectrometer. The mass spectrometer is used in the integral mode to integrate the entire signal from preselected radionuclides, and from this integrated signal the total mass of the respective nuclides can be determined. For CORSOR and VICTORIA, experiments with flowing high pressure hydrogen/steam must flow over the irradiated fuel and then enter the mass spectrometer. For these experiments, a high pressure-high temperature molecular beam inlet must be employed. Finally, in support of VANESA-CORCON, the very highest temperature and molten fuels must be contained and analyzed. Results from all types of experiments will be discussed and their applicability to present and future code development will also be covered

  5. Deformation of high-temperature superconductors

    International Nuclear Information System (INIS)

    Goretta, K.C.; Routbort, J.L.; Miller, D.J.; Chen, N.; Dominguez-Rodriguez, A.; Jimenez-Melendo, M.; De Arellano-Lopez, A.R.

    1994-08-01

    Of the many families of high-temperature superconductors, only the properties of those discovered prior to 1989 - Y-Ba-Cu-O, Tl-Ba(Sr)-Ca-Cu-O, and Bi(Pb)-Sr-Ca-Cu-O - have been studied extensively. Deformation tests have been performed on YBa 2 Cu 3 O x (Y-123), YBa 2 Cu 4 O x (Y-124), TlBa 2 Ca 2 Cu 3 O x (Bi-2223). The tests have revealed that plasticity is generally limited in these compounds and that the rate-controlling diffusional kinetics for creep are very slow. Nevertheless, hot forming has proved to be quite successful for fabrication of bulk high-temperature superconductors, so long as deformation rates are low or large hydrostatic stresses are applied. Steady-state creep data have proved to be useful in designing optimal heat treatments for superconductors and in support of more-fundamental diffusion experiments. The high-temperature superconductors are highly complex oxides, and it is a challenge to understand their deformation responses. In this paper, results of interest and operant creep mechanisms will be reviewed

  6. High temperature cogeneration with thermionic burners

    International Nuclear Information System (INIS)

    Fitzpatrick, G.O.; Britt, E.J.; Dick, R.S.

    1981-01-01

    The thermionic cogeneration combustor was conceived to meet industrial requirements for high-temperature direct heat, typically in the form of gas at temperatures from 800 to 1900 K, while at the same time supplying electricity. The thermionic combustor is entirely self-contained, with heat from the combustion region absorbed by the emitters of thermionic converters to be converted to electric power and the high-temperature reject heat from the converters used to preheat the air used for combustion. Depending on the temperature of the process gas produced, energy savings of around 10% with respect to that used to produce the same amount of electricity and heat without cogeneration are possible with present technology, and savings of up to 20% may be possible with advanced converters. Possible thermionic combustor designs currently under investigation include a configuration in which heat is collected by heat pipes lining the periphery of the combustion region, and a fire-tube converter in which combustion occurs within the cylindrical emitter of each converter. Preliminary component tests of these designs have been encouraging

  7. Medium Deep High Temperature Heat Storage

    Science.gov (United States)

    Bär, Kristian; Rühaak, Wolfram; Schulte, Daniel; Welsch, Bastian; Chauhan, Swarup; Homuth, Sebastian; Sass, Ingo

    2015-04-01

    Heating of buildings requires more than 25 % of the total end energy consumption in Germany. Shallow geothermal systems for indirect use as well as shallow geothermal heat storage systems like aquifer thermal energy storage (ATES) or borehole thermal energy storage (BTES) typically provide low exergy heat. The temperature levels and ranges typically require a coupling with heat pumps. By storing hot water from solar panels or thermal power stations with temperatures of up to 110 °C a medium deep high temperature heat storage (MDHTS) can be operated on relatively high temperature levels of more than 45 °C. Storage depths of 500 m to 1,500 m below surface avoid conflicts with groundwater use for drinking water or other purposes. Permeability is typically also decreasing with greater depth; especially in the crystalline basement therefore conduction becomes the dominant heat transport process. Solar-thermal charging of a MDHTS is a very beneficial option for supplying heat in urban and rural systems. Feasibility and design criteria of different system configurations (depth, distance and number of BHE) are discussed. One system is designed to store and supply heat (300 kW) for an office building. The required boreholes are located in granodioritic bedrock. Resulting from this setup several challenges have to be addressed. The drilling and completion has to be planned carefully under consideration of the geological and tectonical situation at the specific site.

  8. Evaluation of high temperature capacitor dielectrics

    Science.gov (United States)

    Hammoud, Ahmad N.; Myers, Ira T.

    1992-01-01

    Experiments were carried out to evaluate four candidate materials for high temperature capacitor dielectric applications. The materials investigated were polybenzimidazole polymer and three aramid papers: Voltex 450, Nomex 410, and Nomex M 418, an aramid paper containing 50 percent mica. The samples were heat treated for six hours at 60 C and the direct current and 60 Hz alternating current breakdown voltages of both dry and impregnated samples were obtained in a temperature range of 20 to 250 C. The samples were also characterized in terms of their dielectric constant, dielectric loss, and conductivity over this temperature range with an electrical stress of 60 Hz, 50 V/mil present. Additional measurements are underway to determine the volume resistivity, thermal shrinkage, and weight loss of the materials. Preliminary data indicate that the heat treatment of the films slightly improves the dielectric properties with no influence on their breakdown behavior. Impregnation of the samples leads to significant increases in both alternating and direct current breakdown strength. The results are discussed and conclusions made concerning their suitability as high temperature capacitor dielectrics.

  9. High temperature cogeneration with thermionic burners

    Science.gov (United States)

    Fitzpatrick, G. O.; Britt, E. J.; Dick, R. S.

    The thermionic cogeneration combustor was conceived to meet industrial requirements for high-temperature direct heat, typically in the form of gas at temperatures from 800 to 1900 K, while at the same time supplying electricity. The thermionic combustor is entirely self-contained, with heat from the combustion region absorbed by the emitters of thermionic converters to be converted to electric power and the high-temperature reject heat from the converters used to preheat the air used for combustion. Depending on the temperature of the process gas produced, energy savings of around 10% with respect to that used to produce the same amount of electricity and heat without cogeneration are possible with present technology, and savings of up to 20% may be possible with advanced converters. Possible thermionic combustor designs currently under investigation include a configuration in which heat is collected by heat pipes lining the periphery of the combustion region, and a fire-tube converter in which combustion occurs within the cylindrical emitter of each converter. Preliminary component tests of these designs have been encouraging.

  10. On-line temperature control of fluidized bed incinerator using fuzzy algorithm; Fuzzu seigyo donyu ni yoru ryudosogata shokyakuro unten no jidoka

    Energy Technology Data Exchange (ETDEWEB)

    Okayasu, S.; Kuratani, T.; Imai, H. [Ajinomoto Co. Inc., Tokyo (Japan)

    1995-03-15

    Automatic control of incinerators for their stable operation has been desired for the preservation of the environment in the factory. An on-line fuzzy control system has been successfully introduced for temperature control of the fluidized bed of incinerator for industrial wastes. In this case, manual control can be applied to the plant instead of a PID control system, because of the complexity of the waste materials and the large delay in detection of the temperature change in the fluidized bed sand. On the basis of analyzing the dynamic performance of the process and the know-how of skilled operators, membership functions and fuzzy control rules are selected, then determined carefully for the system. Introduction of the system resulted in almost the same performance as manual control. Subsequently the operators are freed from manual operation in the control room for an hour. 6 refs., 5 figs., 4 tabs.

  11. Low temperature circulating fluidized bed gasification and co-gasification of municipal sewage sludge. Part 1: Process performance and gas product characterization

    DEFF Research Database (Denmark)

    Thomsen, Tobias Pape; Sárossy, Zsuzsa; Gøbel, Benny

    2017-01-01

    Results from five experimental campaigns with Low Temperature Circulating Fluidized Bed (LT-CFB) gasification of straw and/or municipal sewage sludge (MSS) from three different Danish municipal waste water treatment plants in pilot and demonstration scale are analyzed and compared. The gasification...... process is characterized with respect to process stability, process performance and gas product characteristics. All experimental campaigns were conducted at maximum temperatures below 750°C, with air equivalence ratios around 0.12 and with pure silica sand as start-up bed material. A total of 8600kg...... particles in the system. Co-gasification of MSS with sufficient amounts of cereal straw was found to be an effective way to mitigate these issues as well as eliminate thermal MSS drying requirements. Characterization of gas products and process performance showed that even though gas composition varied...

  12. High Molecular Weight Polybenzimidazole Membranes for High Temperature PEMFC

    DEFF Research Database (Denmark)

    Yang, Jingshuai; Cleemann, Lars Nilausen; Steenberg, T.

    2014-01-01

    High temperature operation of proton exchange membrane fuel cells under ambient pressure has been achieved by using phosphoric acid doped polybenzimidazole (PBI) membranes. To optimize the membrane and fuel cells, high performance polymers were synthesized of molecular weights from 30 to 94 kDa w...

  13. Mechanical properties of concrete for power reactor at high temperatures

    International Nuclear Information System (INIS)

    Kawase, Kiyotaka; Tanaka, Hitoshi; Nakano, Masayuki

    1985-01-01

    The purpose of this study is to investigate the mechanical properties of concrete for power reactor at high temperature. This paper presents the creep behavior of concrete at high temperature and the cause by which a specified aggregate is broken at a specified high temperature. The creep coefficient at high temperature is smaller than that at ordinary temperature. (author)

  14. Thermodynamic Temperatures of High-Temperature Fixed Points: Uncertainties Due to Temperature Drop and Emissivity

    Science.gov (United States)

    Castro, P.; Machin, G.; Bloembergen, P.; Lowe, D.; Whittam, A.

    2014-07-01

    This study forms part of the European Metrology Research Programme project implementing the New Kelvin to assign thermodynamic temperatures to a selected set of high-temperature fixed points (HTFPs), Cu, Co-C, Pt-C, and Re-C. A realistic thermal model of these HTFPs, developed in finite volume software ANSYS FLUENT, was constructed to quantify the uncertainty associated with the temperature drop across the back wall of the cell. In addition, the widely applied software package, STEEP3 was used to investigate the influence of cell emissivity. The temperature drop, , relates to the temperature difference due to the net loss of heat from the aperture of the cavity between the back wall of the cavity, viewed by the thermometer, defining the radiance temperature, and the solid-liquid interface of the alloy, defining the transition temperature of the HTFP. The actual value of can be used either as a correction (with associated uncertainty) to thermodynamic temperature evaluations of HTFPs, or as an uncertainty contribution to the overall estimated uncertainty. In addition, the effect of a range of furnace temperature profiles on the temperature drop was calculated and found to be negligible for Cu, Co-C, and Pt-C and small only for Re-C. The effective isothermal emissivity is calculated over the wavelength range from 450 nm to 850 nm for different assumed values of surface emissivity. Even when furnace temperature profiles are taken into account, the estimated emissivities change only slightly from the effective isothermal emissivity of the bare cell. These emissivity calculations are used to estimate the uncertainty in the temperature assignment due to the uncertainty in the emissivity of the blackbody.

  15. High temperature gas cooled nuclear reactor

    International Nuclear Information System (INIS)

    Hosegood, S.B.; Lockett, G.E.

    1975-01-01

    For high-temperature gas cooled reactors it is considered advantageous to design the core so that the moderator blocks can be removed and replaced by some means of standpipes normally situated in the top of the reactor vessel. An arrangement is here described to facilitate these operations. The blocks have end faces shaped as irregular hexagons with three long sides of equal length and three short sides also of equal length, one short side being located between each pair of adjacent long sides, and the long sides being inclined towards one another at 60 0 . The block defines a number of coolant channels located parallel to its sides. Application of the arrangement to a high temperature gas-cooled reactor with refuelling standpipes is described. The standpipes are located in the top of the reactor vessel above the tops of the columns and are disposed coaxially above the hexagonal channels, with diameters that allow the passage of the blocks. (U.K.)

  16. Atomic processes in high temperature plasmas

    International Nuclear Information System (INIS)

    Hahn, Y.

    1990-03-01

    Much theoretical and experimental efforts have been expended in recent years to study those atomic processes which are specially relevant to understanding high temperature laboratory plasmas. For magnetically confined fusion plasmas, the temperature range of interest spans from the hundreds of eV at plasma edges to 10 keV at the center of the plasma, where most of the impurity ions are nearly fully ionized. These highly stripped ions interact strongly with electrons in the plasma, leading to further excitation and ionization of the ions, as well as electron capture. Radiations are emitted during these processes, which easily escape to plasma container walls, thus cooling the plasma. One of the dominant modes of radiation emission has been identified with dielectronic recombination. This paper reviews this work

  17. Metallic Membranes for High Temperature Hydrogen Separation

    DEFF Research Database (Denmark)

    Ma, Y.H.; Catalano, Jacopo; Guazzone, Federico

    2013-01-01

    membrane fabrication methods have matured over the last decades, and the deposition of very thin films (1–5 µm) of Pd over porous ceramics or modified porous metal supports is quite common. The H2 permeances and the selectivities achieved at 400–500 °C were in the order of 50–100 Nm3/m/h/bar0.5 and greater......Composite palladium membranes have extensively been studied in laboratories and, more recently, in small pilot industrial applications for the high temperature separation of hydrogen from reactant mixtures such as water-gas shift (WGS) reaction or methane steam reforming (MSR). Composite Pd...... than 1000, respectively. This chapter describes in detail composite Pd-based membrane preparation methods, which consist of the grading of the support and the deposition of the dense metal layer, their performances, and their applications in catalytic membrane reactors (CMRs) at high temperatures (400...

  18. High temperature superconducting YBCO microwave filters

    Science.gov (United States)

    Aghabagheri, S.; Rasti, M.; Mohammadizadeh, M. R.; Kameli, P.; Salamati, H.; Mohammadpour-Aghdam, K.; Faraji-Dana, R.

    2018-06-01

    Epitaxial thin films of YBCO high temperature superconductor are widely used in telecommunication technology such as microwave filter, antenna, coupler and etc., due to their lower surface resistance and lower microwave loss than their normal conductor counterparts. Thin films of YBCO were fabricated by PLD technique on LAO substrate. Transition temperature and width were 88 K and 3 K, respectively. A filter pattern was designed and implemented by wet photolithography method on the films. Characterization of the filter at 77 K has been compared with the simulation results and the results for a made gold filter. Both YBCO and gold filters show high microwave loss. For YBCO filter, the reason may be due to the improper contacts on the feedlines and for gold filter, low thickness of the gold film has caused the loss increased.

  19. Refractiry metal monocrystals in high temperature thermometry

    International Nuclear Information System (INIS)

    Kuritnyk, I.P.

    1988-01-01

    The regularities of changes in thermoelectric properties of refractory metals in a wide temperature range (300-2300 K) depending on their structural state and impurities, are generalized. It is found that the main reasons for changes in thermo-e.m.f. of refractory metals during their operation in various media are diffusion processes and local microvoltages appearing in nonhomogeneous thermoelectrodes. It is shown that microstructure formation and control of impurities in thermometric materials permit to improve considerably the metrologic parameters of thermal transformers. Tungsten and molybdenum with monocrystalline structure with their high stability of properties, easy to manufacture and opening new possibilities in high-temperature contact measurement are used in thermometry for the first time

  20. Preparation of silver doped high temperature superconductors

    International Nuclear Information System (INIS)

    Stavek, Jiri; Zapletal, Vladimir

    1989-01-01

    High temperature superconductors were prepared by the controlled double-jet precipitation to manipulate the chemical composition, composition gradients, average grain size, grain size distribution, and other factors which contribute to the actual properties and performance of HTSC. The cations (Y-Ba-Cu or Bi-Pb-Ca-Sr-Cu) and oxalic anions solutions were simultaneously separately introduced to the crystallizer with a stirred solution of gelatin under conditions where the temperature, excess of oxalic anions in solution, pH, reactant addition rate, and other reaction conditions were tightly controlled to prepare the high sinterability powder. To increase the sinterability of submicron particles of produced precursor, the silver ions were introduced at the end of the controlled double-jet precipitation. This approach improves the electrical and mechanical properties of produced HTSC specimens. The controlled double jet precipitation provides a viable technique for preparation of oxide superconductors and the process is amenable for scaling up

  1. High Temperature Phenomena in Shock Waves

    CERN Document Server

    2012-01-01

    The high temperatures generated in gases by shock waves give rise to physical and chemical phenomena such as molecular vibrational excitation, dissociation, ionization, chemical reactions and inherently related radiation. In continuum regime, these processes start from the wave front, so that generally the gaseous media behind shock waves may be in a thermodynamic and chemical non-equilibrium state. This book presents the state of knowledge of these phenomena. Thus, the thermodynamic properties of high temperature gases, including the plasma state are described, as well as the kinetics of the various chemical phenomena cited above. Numerous results of measurement and computation of vibrational relaxation times, dissociation and reaction rate constants are given, and various ionization and radiative mechanisms and processes are presented. The coupling between these different phenomena is taken into account as well as their interaction with the flow-field. Particular points such as the case of rarefied flows an...

  2. Gas cleaning with hot char beds studied by stable isotopes

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Ahrenfeldt, Jesper; Ambus, Per

    2014-01-01

    The chemistry taking place in a high temperature char bed used for binding aromatic tar compounds has been studied in detail. 13C labelled tar compounds were used to trace the incorporation into the char bed using isotope ratio mass spectrometry (IRMS) and GC-MS. Furthermore, compounds labelled...

  3. HIGH ASPECT RATIO ION EXCHANGE RESIN BED - HYDRAULIC RESULTS FOR SPERICAL RESIN BEADS

    International Nuclear Information System (INIS)

    Duignan, M; Charles Nash, C; Timothy Punch, T

    2007-01-01

    A principal role of the DOE Savannah River Site is to safely dispose of a large volume of liquid nuclear waste held in many storage tanks. An in-tank ion exchange unit is being considered for cesium removal to accelerate waste processing. This unit is planned to have a relatively high bed height to diameter ratio (10:1). Complicating the design is the need to cool the ion exchange media; therefore, the ion exchange column will have a central cooling core making the flow path annular. To separate cesium from waste the media being considered is made of resorcinol formaldehyde resin deposited on spherical plastic beads and is a substitute for a previously tested resin made of crystalline silicotitanate. This spherical media not only has an advantage of being mechanically robust, but, unlike its predecessor, it is also reusable, that is, loaded cesium can be removed through elution and regeneration. Resin regeneration leads to more efficient operation and less spent resin waste, but its hydraulic performance in the planned ion exchange column was unknown. Moreover, the recycling process of this spherical resorcinol formaldehyde causes its volume to significantly shrink and swell. To determine the spherical media's hydraulic demand a linearly scaled column was designed and tested. The waste simulant used was prototypic of the wastes' viscosity and density. This paper discusses the hydraulic performance of the media that will be used to assist in the design of a full-scale unit

  4. Bed agglomeration in fluidized combustor fueled by wood and rice straw blends

    DEFF Research Database (Denmark)

    Thy, Peter; Jenkins, Brian; Williams, R.B.

    2010-01-01

    Abstract Petrographic techniques have been used to examine bed materials from fluidized bed combustion experiments that utilized wood and rice straw fuel blends. The experiments were conducted using a laboratory-scale combustor with mullite sand beds, firing temperatures of 840 to 1030 °C, and run...... areas between bed particles, ultimately led to bed agglomeration. The interfaces and the presence of gas bubbles in the cement suggest a bonding material with a high surface tension and a liquid state. The cement films originate by filling of irregularities on individual and partially agglomerated bed...

  5. High Temperature Studies of La-Monazite

    Science.gov (United States)

    2004-07-01

    Hay, E. Boakeye, M. D. Petry, Y. Berta, K. Von Lehmden, and J. Welch, " 5 A. Meldrum , L. A. Boatner, and R. C. Ewing, "Electron-Irradiation-Induced... Meldrum , L. A. Boatner, and R. C. Ewing, "A Comparison of Radiation Alumina-based Fiber for High Temperature Composite Reinforcement," Ceram. Eng... acid . The processing included procedures that allowed the La/P ratio to be controlled to be very close to the stoichiometric value of unity (within less

  6. Passivation Of High-Temperature Superconductors

    Science.gov (United States)

    Vasquez, Richard P.

    1991-01-01

    Surfaces of high-temperature superconductors passivated with native iodides, sulfides, or sulfates formed by chemical treatments after superconductors grown. Passivating compounds nearly insoluble in and unreactive with water and protect underlying superconductors from effects of moisture. Layers of cuprous iodide and of barium sulfate grown. Other candidate passivating surface films: iodides and sulfides of bismuth, strontium, and thallium. Other proposed techniques for formation of passivating layers include deposition and gas-phase reaction.

  7. High Temperature Perforating System for Geothermal Applications

    Energy Technology Data Exchange (ETDEWEB)

    Smart, Moises E. [Schlumberger Technology Corporation, Sugar Land, TX (United States)

    2017-02-28

    The objective of this project is to develop a perforating system consisting of all the explosive components and hardware, capable of reliable performance in high temperatures geothermal wells (>200 ºC). In this light we will focused on engineering development of these components, characterization of the explosive raw powder and developing the internal infrastructure to increase the production of the explosive from laboratory scale to industrial scale.

  8. Intermetallic-Based High-Temperature Materials

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    1999-04-25

    The intermetallic-based alloys for high-temperature applications are introduced. General characteristics of intermetallics are followed by identification of nickel and iron aluminides as the most practical alloys for commercial applications. An overview of the alloy compositions, melting processes, and mechanical properties for nickel and iron aluminizes are presented. The current applications and commercial producers of nickel and iron aluminizes are given. A brief description of the future prospects of intermetallic-based alloys is also given.

  9. The modular high temperature gas cooled reactor

    International Nuclear Information System (INIS)

    Lutz, D.E.; Lipps, A.J.

    1984-01-01

    Due to relatively high operating temperatures, the gas-cooled reactor has the potential to serve a wide variety of energy applications. This paper discusses the energy applications which can be served by the modular HTGR, the magnitude of the potential markets, and the HTGR product cost incentives relative to fossil fuel competition. Advantages of the HTGR modular systems are presented along with a description of the design features and performance characteristics of the current reference HTGR modular systems

  10. Establishment of Harrop, High-Temperature Viscometer

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.F.

    1999-11-05

    This report explains how the Harrop, High-Temperature Viscometer was installed, calibrated, and operated. This report includes assembly and alignment of the furnace, viscometer, and spindle, and explains the operation of the Brookfield Viscometer, the Harrop furnace, and the UDC furnace controller. Calibration data and the development of the spindle constant from NIST standard reference glasses is presented. A simple operational procedure is included.

  11. Apparatus for distilling dry solids. [high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Constant, M

    1873-09-09

    In the proposed system under the action of high temperature, the vapors commence to form, and on account of their density go toward the lower part of the retort, where they take the place of air; then they find the exit prepared for them and run out literally by their weight as they are formed and enter the coil where all that can are completely condensed into oil.

  12. Internal modes in high-temperature plasmas

    International Nuclear Information System (INIS)

    Crew, G.B.

    1983-02-01

    The linear stability of current-carrying toroidal plamsas is examined to determine the possibility of exciting global internal modes. The ideal magnetohydrodynamic (MHD) theory provides a useful framework for the analysis of these modes, which involve a kinking of the central portion of the plasma column. Non-ideal effects can also be important, and these are treated for high-temperature regimes where the plasma is collisionless

  13. High-temperature flaw assessment procedure

    International Nuclear Information System (INIS)

    Ruggles, M.B.; Takahashi, Y.; Ainsworth, R.A.

    1989-08-01

    The current program represents a joint effort between the Electric Power Research Institute (EPRI) in the USA, the Central Research Institute of Electric Power Industry (CRIEPI) in Japan, and the Central Electricity Generating Board (CEGB) in the UK. The goal is to develop an interim high-temperature flaw assessment procedure for high-temperature reactor components. This is to be accomplished through exploratory experimental and analytical studies of high-temperature crack growth. The state-of-the-art assessment and the fracture mechanics database for both types 304 and 316 stainless steels, completed in 1988, serve as a foundation for the present work. Work in the three participating organizations is progressing roughly on schedule. Results to-date are presented in this document. Fundamental tests results are discussed in Section 2. Section 3 focuses on results of exploratory subcritical crack growth tests. Progress in subcritical crack growth modeling is reported in Section 4. Exploratory failure tests are outlined in Section 5. 21 refs., 70 figs., 7 tabs

  14. Elasticity of fluorite at high temperatures

    Science.gov (United States)

    Eke, J.; Tennakoon, S.; Mookherjee, M.

    2017-12-01

    Fluorite (CaF2) is a simple halide with cubic space group symmetry (Fm-3m) and is often used as an internal pressure calibrant in moderate high-pressure/high-temperature experiments [1]. In order to gain insight into the elastic behavior of fluorite, we have conducted Resonant Ultrasound Spectroscopy (RUS) on a single crystal of fluorite with rectangular parallelepiped geometry. Using single crystal X-ray diffraction, we aligned the edges of the rectangular parallelepiped with [-1 1 1], [-1 1 -2], and [-1 -1 0] crystallographic directions. We conducted the RUS measurements up to 620 K. RUS spectra are influenced by the geometry, density, and the full elastic moduli tensor of the material. In our high-temperature RUS experiments, the geometry and density were constrained using thermal expansion from previous studies [2]. We determined the elasticity by minimizing the difference between observed resonance and calculated Eigen frequency using Rayleigh-Ritz method [3]. We found that at room temperature, the single crystal elastic moduli for fluorite are 170, 49, and 33 GPa for C11, C12, and C44 respectively. At room temperatures, the aggregate bulk modulus (K) is 90 GPa and the shear modulus (G) is 43 GPa. We note that the elastic moduli and sound wave velocities decrease linearly as a function of temperature with dVP /dT and dVS /dT being -9.6 ×10-4 and -5.0 ×10-4 km/s/K respectively. Our high-temperature RUS results are in good agreement with previous studies on fluorite using both Ultrasonic methods and Brillouin scattering [4,5]. Acknowledgement: This study is supported by US NSF awards EAR-1639552 and EAR-1634422. References: [1] Speziale, S., Duffy, T. S. 2002, Phys. Chem. Miner., 29, 465-472; [2] Roberts, R. B., White, G. K., 1986, J. Phys. C: Solid State Phys., 19, 7167-7172. [3] Migliori, A., Maynard, J. D., 2005, Rev. Sci. Instrum., 76, 121301. [4] Catlow, C. R. A., Comins, J. D., Germano, F. A., Harley, R. T., Hayes, W., 1978, J. Phys. C Solid State Phys

  15. An in situ spatially resolved analytical technique to simultaneously probe gas phase reactions and temperature within the packed bed of a plug flow reactor.

    Science.gov (United States)

    Touitou, Jamal; Burch, Robbie; Hardacre, Christopher; McManus, Colin; Morgan, Kevin; Sá, Jacinto; Goguet, Alexandre

    2013-05-21

    This paper reports the detailed description and validation of a fully automated, computer controlled analytical method to spatially probe the gas composition and thermal characteristics in packed bed systems. As an exemplar, we have examined a heterogeneously catalysed gas phase reaction within the bed of a powdered oxide supported metal catalyst. The design of the gas sampling and the temperature recording systems are disclosed. A stationary capillary with holes drilled in its wall and a moveable reactor coupled with a mass spectrometer are used to enable sampling and analysis. This method has been designed to limit the invasiveness of the probe on the reactor by using the smallest combination of thermocouple and capillary which can be employed practically. An 80 μm (O.D.) thermocouple has been inserted in a 250 μm (O.D.) capillary. The thermocouple is aligned with the sampling holes to enable both the gas composition and temperature profiles to be simultaneously measured at equivalent spatially resolved positions. This analysis technique has been validated by studying CO oxidation over a 1% Pt/Al2O3 catalyst and the spatial resolution profiles of chemical species concentrations and temperature as a function of the axial position within the catalyst bed are reported.

  16. Fluidized-bed nuclear reactor

    International Nuclear Information System (INIS)

    Grimmett, E.S.; Kunze, J.F.

    1975-01-01

    A reactor vessel containing a fluidized-bed region of particulate material including both a neutron-moderating and a fertile substance is described. A gas flow including fissile material passes through the vessel at a sufficient rate to fluidize the particulate material and at a sufficient density to support a thermal fission reaction within the fluidized-bed region. The high-temperature portion of a heat transfer system is located within the fluidized-bed region of the reactor vessel in direct contact with the fluidized particles. Heat released by fission is thereby transferred at an enhanced rate to a coolant circulating within the heat transfer system. Fission products are continuously removed from the gas flow and supplemental fissile material added during the reactor operation. (U.S.)

  17. High energy nuclear database: a test-bed for nuclear data information technology

    International Nuclear Information System (INIS)

    Brown, D.A.; Vogt, R.; Beck, B.; Pruet, J.; Vogt, R.

    2008-01-01

    We describe the development of an on-line high-energy heavy-ion experimental database. When completed, the database will be searchable and cross-indexed with relevant publications, including published detector descriptions. While this effort is relatively new, it will eventually contain all published data from older heavy-ion programs as well as published data from current and future facilities. These data include all measured observables in proton-proton, proton-nucleus and nucleus-nucleus collisions. Once in general use, this database will have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models for a broad range of experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for inertial confinement fusion, target and source development for upcoming facilities such as the International Linear Collider and homeland security. This database is part of a larger proposal that includes the production of periodic data evaluations and topical reviews. These reviews would provide an alternative and impartial mechanism to resolve discrepancies between published data from rival experiments and between theory and experiment. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support. This project serves as a test-bed for the further development of an object-oriented nuclear data format and database system. By using 'off-the-shelf' software tools and techniques, the system is simple, robust, and extensible. Eventually we envision a 'Grand Unified Nuclear Format' encapsulating data types used in the ENSDF, Endf/B, EXFOR, NSR and other formats, including processed data formats. (authors)

  18. Low temperature circulating fluidized bed gasification and co-gasification of municipal sewage sludge. Part 2: Evaluation of ash materials as phosphorus fertilizer.

    Science.gov (United States)

    Thomsen, Tobias Pape; Hauggaard-Nielsen, Henrik; Gøbel, Benny; Stoholm, Peder; Ahrenfeldt, Jesper; Henriksen, Ulrik B; Müller-Stöver, Dorette Sophie

    2017-08-01

    The study is part 2 of 2 in an investigation of gasification and co-gasification of municipal sewage sludge in low temperature gasifiers. In this work, solid residuals from thermal gasification and co-gasification of municipal sewage sludge were investigated for their potential use as fertilizer. Ashes from five different low temperature circulating fluidized bed (LT-CFB) gasification campaigns including two mono-sludge campaigns, two sludge/straw mixed fuels campaigns and a straw reference campaign were compared. Experiments were conducted on two different LT-CFBs with thermal capacities of 100kW and 6MW, respectively. The assessment included: (i) Elemental composition and recovery of key elements and heavy metals; (ii) content of total carbon (C) and total nitrogen (N); (iii) pH; (iv) water extractability of phosphorus after incubation in soil; and (v) plant phosphorus response measured in a pot experiment with the most promising ash material. Co-gasification of straw and sludge in LT-CFB gasifiers produced ashes with a high content of recalcitrant C, phosphorus (P) and potassium (K), a low content of heavy metals (especially cadmium) and an improved plant P availability compared to the mono-sludge ashes, thereby showing the best fertilizer qualities among all assessed materials. It was also found that bottom ashes from the char reactor contained even less heavy metals than cyclone ashes. It is concluded that LT-CFB gasification and co-gasification is a highly effective way to purify and sanitize sewage sludge for subsequent use in agricultural systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. High temperature aqueous stress corrosion testing device

    International Nuclear Information System (INIS)

    Bornstein, A.N.; Indig, M.E.

    1975-01-01

    A description is given of a device for stressing tensile samples contained within a high temperature, high pressure aqueous environment, thereby permitting determination of stress corrosion susceptibility of materials in a simple way. The stressing device couples an external piston to an internal tensile sample via a pull rod, with stresses being applied to the sample by pressurizing the piston. The device contains a fitting/seal arrangement including Teflon and weld seals which allow sealing of the internal system pressure and the external piston pressure. The fitting/seal arrangement allows free movement of the pull rod and the piston

  20. Structural relationships in high temperature superconductors

    International Nuclear Information System (INIS)

    Schuller, I.K.; Segre, C.U.; Hinks, D.G.; Jorgensen, J.D.; Soderholm, L.; Beno, M.; Zhang, K.

    1987-09-01

    The recent discovery of two types of metallic copper oxide compounds which are superconducting to above 90 0 K has renewed interest in the search for new high temperature superconducting materials. It is significant that both classes of compounds, La/sub 2-x/Sr/sub x/CuO/sub 4-y/ and YBa 2 Cu 3 O/sub 7-δ/ are intimately related to the extensively studied perovskite family. Both compounds contain highly oxidized, covalently bonded Cu-O sublattices, however, they differ in geometry. In this paper we discuss the relationship of these features to the superconducting properties. 30 refs., 6 figs

  1. Preparation and characterization of thin-film Pd–Ag supported membranes for high-temperature applications

    NARCIS (Netherlands)

    Fernandez Gesalaga, Ekain; Coenen, Kai; Helmi Siasi Farimani, Arash; Melendez, J.; Zuniga, Jon; Pacheco Tanaka, David Alfredo; van Sint Annaland, Martin; Gallucci, Fausto

    2015-01-01

    This paper reports the preparation, characterization and stability tests of thin-film Pd–Ag supported membranes for high-temperature fluidized bed membrane reactor applications. Various thin-film supported membranes have been prepared by simultaneous Pd–Ag electroless plating and have been initially

  2. Effects of water vapor pretreatment time and reaction temperature on CO(2) capture characteristics of a sodium-based solid sorbent in a bubbling fluidized-bed reactor.

    Science.gov (United States)

    Seo, Yongwon; Jo, Sung-Ho; Ryu, Chong Kul; Yi, Chang-Keun

    2007-10-01

    CO(2) capture from flue gas using a sodium-based solid sorbent was investigated in a bubbling fluidized-bed reactor. Carbonation and regeneration temperature on CO(2) removal was determined. The extent of the chemical reactivity after carbonation or regeneration was characterized via (13)C NMR. In addition, the physical properties of the sorbent such as pore size, pore volume, and surface area after carbonation or regeneration were measured by gas adsorption method (BET). With water vapor pretreatment, near complete CO(2) removal was initially achieved and maintained for about 1-2min at 50 degrees C with 2s gas residence time, while without proper water vapor pretreatment CO(2) removal abruptly decreased from the beginning. Carbonation was effective at the lower temperature over the 50-70 degrees C temperature range, while regeneration more effective at the higher temperature over the 135-300 degrees C temperature range. To maintain the initial 90% CO(2) removal, it would be necessary to keep the regeneration temperature higher than about 135 degrees C. The results obtained in this study can be used as basic data for designing and operating a large scale CO(2) capture process with two fluidized-bed reactors.

  3. High temperature measurement of water vapor absorption

    Science.gov (United States)

    Keefer, Dennis; Lewis, J. W. L.; Eskridge, Richard

    1985-01-01

    An investigation was undertaken to measure the absorption coefficient, at a wavelength of 10.6 microns, for mixtures of water vapor and a diluent gas at high temperature and pressure. The experimental concept was to create the desired conditions of temperature and pressure in a laser absorption wave, similar to that which would be created in a laser propulsion system. A simplified numerical model was developed to predict the characteristics of the absorption wave and to estimate the laser intensity threshold for initiation. A non-intrusive method for temperature measurement utilizing optical laser-beam deflection (OLD) and optical spark breakdown produced by an excimer laser, was thoroughly investigated and found suitable for the non-equilibrium conditions expected in the wave. Experiments were performed to verify the temperature measurement technique, to screen possible materials for surface initiation of the laser absorption wave and to attempt to initiate an absorption wave using the 1.5 kW carbon dioxide laser. The OLD technique was proven for air and for argon, but spark breakdown could not be produced in helium. It was not possible to initiate a laser absorption wave in mixtures of water and helium or water and argon using the 1.5 kW laser, a result which was consistent with the model prediction.

  4. Process heat cogeneration using a high temperature reactor

    International Nuclear Information System (INIS)

    Alonso, Gustavo; Ramirez, Ramon; Valle, Edmundo del; Castillo, Rogelio

    2014-01-01

    Highlights: • HTR feasibility for process heat cogeneration is assessed. • A cogeneration coupling for HTR is proposed and process heat cost is evaluated. • A CCGT process heat cogeneration set up is also assessed. • Technical comparison between both sources of cogeneration is performed. • Economical competitiveness of the HTR for process heat cogeneration is analyzed. - Abstract: High temperature nuclear reactors offer the possibility to generate process heat that could be used in the oil industry, particularly in refineries for gasoline production. These technologies are still under development and none of them has shown how this can be possible and what will be the penalty in electricity generation to have this additional product and if the cost of this subproduct will be competitive with other alternatives. The current study assesses the likeliness of generating process heat from Pebble Bed Modular Reactor to be used for a refinery showing different plant balances and alternatives to produce and use that process heat. An actual practical example is presented to demonstrate the cogeneration viability using the fact that the PBMR is a modular small reactor where the cycle configuration to transport the heat of the reactor to the process plant plays an important role in the cycle efficiency and in the plant economics. The results of this study show that the PBMR would be most competitive when capital discount rates are low (5%), carbon prices are high (>30 US$/ton), and competing natural gas prices are at least 8 US$/mmBTU

  5. Process heat cogeneration using a high temperature reactor

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, Gustavo, E-mail: gustavoalonso3@gmail.com [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico); Instituto Politécnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Ed. 9, Lindavista, D.F. 07300 (Mexico); Ramirez, Ramon [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico); Valle, Edmundo del [Instituto Politécnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Ed. 9, Lindavista, D.F. 07300 (Mexico); Castillo, Rogelio [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico)

    2014-12-15

    Highlights: • HTR feasibility for process heat cogeneration is assessed. • A cogeneration coupling for HTR is proposed and process heat cost is evaluated. • A CCGT process heat cogeneration set up is also assessed. • Technical comparison between both sources of cogeneration is performed. • Economical competitiveness of the HTR for process heat cogeneration is analyzed. - Abstract: High temperature nuclear reactors offer the possibility to generate process heat that could be used in the oil industry, particularly in refineries for gasoline production. These technologies are still under development and none of them has shown how this can be possible and what will be the penalty in electricity generation to have this additional product and if the cost of this subproduct will be competitive with other alternatives. The current study assesses the likeliness of generating process heat from Pebble Bed Modular Reactor to be used for a refinery showing different plant balances and alternatives to produce and use that process heat. An actual practical example is presented to demonstrate the cogeneration viability using the fact that the PBMR is a modular small reactor where the cycle configuration to transport the heat of the reactor to the process plant plays an important role in the cycle efficiency and in the plant economics. The results of this study show that the PBMR would be most competitive when capital discount rates are low (5%), carbon prices are high (>30 US$/ton), and competing natural gas prices are at least 8 US$/mmBTU.

  6. High-temperature helium-loop facility

    International Nuclear Information System (INIS)

    Tokarz, R.D.

    1981-09-01

    The high-temperature helium loop is a facility for materials testing in ultrapure helium gas at high temperatures. The closed loop system is capable of recirculating high-purity helium or helium with controlled impurities. The gas loop maximum operating conditions are as follows: 300 psi pressure, 500 lb/h flow rate, and 2100 0 F temperature. The two test sections can accept samples up to 3.5 in. diameter and 5 ft long. The gas loop is fully instrumented to continuously monitor all parameters of loop operation as well as helium impurities. The loop is fully automated to operate continuously and requires only a daily servicing by a qualified operator to replenish recorder charts and helium makeup gas. Because of its versatility and high degree of parameter control, the helium loop is applicable to many types of materials research. This report describes the test apparatus, operating parameters, peripheral systems, and instrumentation system. The experimental capabilities and test conand presents the results that have been obtained. The study has been conducted using a four-phase approach. The first phase develops the solution to the steady-state radon-diffusion equation in one-dimensieered barriers; disposal charge analysis; analysis of spent fuel policy implementation; spent f water. Field measurements and observations are reported for each site. Analytical data and field measurements are presented in tables and maps. Uranium concentrations in the sediments which were above detection limits ranged from 0.10 t 51.2 ppM. The mean of the logarithms of the uranium concentrations was 0.53. A group of high uranium concentrations occurs near the junctions of quadrangles AB, AC, BB, a 200 mK. In case 2), x-ray studies of isotopic phase separation in 3 He-- 4 He bcc solids were carried out by B. A. Fraass

  7. Weak links in high critical temperature superconductors

    Science.gov (United States)

    Tafuri, Francesco; Kirtley, John R.

    2005-11-01

    The traditional distinction between tunnel and highly transmissive barriers does not currently hold for high critical temperature superconducting Josephson junctions, both because of complicated materials issues and the intrinsic properties of high temperature superconductors (HTS). An intermediate regime, typical of both artificial superconductor-barrier-superconductor structures and of grain boundaries, spans several orders of magnitude in the critical current density and specific resistivity. The physics taking place at HTS surfaces and interfaces is rich, primarily because of phenomena associated with d-wave order parameter (OP) symmetry. These phenomena include Andreev bound states, the presence of the second harmonic in the critical current versus phase relation, a doubly degenerate state, time reversal symmetry breaking and the possible presence of an imaginary component of the OP. All these effects are regulated by a series of transport mechanisms, whose rules of interplay and relative activation are unknown. Some transport mechanisms probably have common roots, which are not completely clear and possibly related to the intrinsic nature of high-TC superconductivity. The d-wave OP symmetry gives unique properties to HTS weak links, which do not have any analogy with systems based on other superconductors. Even if the HTS structures are not optimal, compared with low critical temperature superconductor Josephson junctions, the state of the art allows the realization of weak links with unexpectedly high quality quantum properties, which open interesting perspectives for the future. The observation of macroscopic quantum tunnelling and the qubit proposals represent significant achievements in this direction. In this review we attempt to encompass all the above aspects, attached to a solid experimental basis of junction concepts and basic properties, along with a flexible phenomenological background, which collects ideas on the Josephson effect in the presence

  8. Weak links in high critical temperature superconductors

    International Nuclear Information System (INIS)

    Tafuri, Francesco; Kirtley, John R

    2005-01-01

    The traditional distinction between tunnel and highly transmissive barriers does not currently hold for high critical temperature superconducting Josephson junctions, both because of complicated materials issues and the intrinsic properties of high temperature superconductors (HTS). An intermediate regime, typical of both artificial superconductor-barrier-superconductor structures and of grain boundaries, spans several orders of magnitude in the critical current density and specific resistivity. The physics taking place at HTS surfaces and interfaces is rich, primarily because of phenomena associated with d-wave order parameter (OP) symmetry. These phenomena include Andreev bound states, the presence of the second harmonic in the critical current versus phase relation, a doubly degenerate state, time reversal symmetry breaking and the possible presence of an imaginary component of the OP. All these effects are regulated by a series of transport mechanisms, whose rules of interplay and relative activation are unknown. Some transport mechanisms probably have common roots, which are not completely clear and possibly related to the intrinsic nature of high-T C superconductivity. The d-wave OP symmetry gives unique properties to HTS weak links, which do not have any analogy with systems based on other superconductors. Even if the HTS structures are not optimal, compared with low critical temperature superconductor Josephson junctions, the state of the art allows the realization of weak links with unexpectedly high quality quantum properties, which open interesting perspectives for the future. The observation of macroscopic quantum tunnelling and the qubit proposals represent significant achievements in this direction. In this review we attempt to encompass all the above aspects, attached to a solid experimental basis of junction concepts and basic properties, along with a flexible phenomenological background, which collects ideas on the Josephson effect in the presence

  9. Malaria in pregnant women in an area with sustained high coverage of insecticide-treated bed nets

    Directory of Open Access Journals (Sweden)

    Mshinda Hassan

    2008-07-01

    Full Text Available Abstract Background Since 2000, the World Health Organization has recommended a package of interventions to prevent malaria during pregnancy and its sequelae that includes the promotion of insecticide-treated bed nets (ITNs, intermittent preventive treatment in pregnancy (IPTp, and effective case management of malarial illness. It is recommended that pregnant women in malaria-endemic areas receive at least two doses of sulphadoxine-pyrimethamine in the second and third trimesters of pregnancy. This study assessed the prevalence of placental malaria at delivery in women during 1st or 2nd pregnancy, who did not receive intermittent preventive treatment for malaria (IPTp in a malaria-endemic area with high bed net coverage. Methods A hospital-based cross-sectional study was done in Ifakara, Tanzania, where bed net coverage is high. Primi- and secundigravid women, who presented to the labour ward and who reported not using IPTp were included in the study. Self-report data were collected by questionnaire; whereas neonatal birth weight and placenta parasitaemia were measured directly at the time of delivery. Results Overall, 413 pregnant women were enrolled of which 91% reported to have slept under a bed net at home the previous night, 43% reported history of fever and 62% were primigravid. Malaria parasites were detected in 8% of the placenta samples; the geometric mean (95%CI placental parasite density was 3,457 (1,060–11,271 parasites/μl in primigravid women and 2,178 (881–5,383 parasites/μl in secundigravid women. Fifteen percent of newborns weighed Conclusion The observed incidence of LBW and prevalence of placental parasitaemia at delivery suggests that malaria remains a problem in pregnancy in this area with high bed net coverage when eligible women do not receive IPTp. Delivery of IPTp should be emphasized at all levels of implementation to achieve maximum community coverage.

  10. High-temperature brushless DC motor controller

    Science.gov (United States)

    Cieslewski, Crzegorz; Lindblom, Scott C.; Maldonado, Frank J.; Eckert, Michael Nathan

    2017-05-16

    A motor control system for deployment in high temperature environments includes a controller; a first half-bridge circuit that includes a first high-side switching element and a first low-side switching element; a second half-bridge circuit that includes a second high-side switching element and a second low-side switching element; and a third half-bridge circuit that includes a third high-side switching element and a third; low-side switching element. The motor controller is arranged to apply a pulse width modulation (PWM) scheme to switch the first half-bridge circuit, second half-bridge circuit, and third half-bridge circuit to power a motor.

  11. The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17°C and 22°C

    Directory of Open Access Journals (Sweden)

    Shin M

    2016-04-01

    Full Text Available Mirim Shin,1 Mark Halaki,1 Paul Swan,2 Angus Ireland,2 Chin Moi Chow1 1Exercise, Health and Performance Research Group, Faculty of Health Sciences, The University of Sydney, Lidcombe, 2Australian Wool Innovation Limited, The Woolmark Company, Sydney, NSW, Australia Abstract: The fibers used in clothing and bedding have different thermal properties. This study aimed to investigate the influences of textile fabrics on sleep under different ambient temperature (Ta conditions. Seventeen healthy young participants (ten males underwent nine nights of polysomnography testing including an adaptation night. Participants were randomized to each of the three binary factors: sleepwear (cotton vs wool, bedding (polyester vs wool, and Ta (17°C vs 22°C with relative humidity set at 60%. Skin temperature (Tsk and core temperature (Tc were monitored throughout the sleep period. Sleep onset latency (SOL was significantly shortened when sleeping in wool with trends of increased total sleep time and sleep efficiency compared to cotton sleepwear. At 17°C, the proportion of sleep stages 1 (%N1 and 3 (%N3 and rapid eye movement sleep was higher, but %N2 was lower than at 22°C. Interaction effects (sleepwear × Ta showed a significantly shorter SOL for wool than cotton at 17°C but lower %N3 for wool than cotton at 22°C. A significantly lower %N2 but higher %N3 was observed for wool at 17°C than at 22°C. There was no bedding effect on sleep. Several temperature variables predicted the sleep findings in a stepwise multiple regression analysis and explained 67.8% of the variance in SOL and to a lesser degree the %N2 and %N3. These findings suggest that sleepwear played a contributory role to sleep outcomes and participants slept better at 17°C than at 22°C.Keywords: cotton, polyester, wool, polysomnography, skin temperature, core body temperature

  12. Microstructural Evolution and Mechanical Behavior of High Temperature Solders: Effects of High Temperature Aging

    Science.gov (United States)

    Hasnine, M.; Tolla, B.; Vahora, N.

    2018-04-01

    This paper explores the effects of aging on the mechanical behavior, microstructure evolution and IMC formation on different surface finishes of two high temperature solders, Sn-5 wt.% Ag and Sn-5 wt.% Sb. High temperature aging showed significant degradation of Sn-5 wt.% Ag solder hardness (34%) while aging has little effect on Sn-5 wt.% Sb solder. Sn-5 wt.% Ag experienced rapid grain growth as well as the coarsening of particles during aging. Sn-5 wt.% Sb showed a stable microstructure due to solid solution strengthening and the stable nature of SnSb precipitates. The increase of intermetallic compound (IMC) thickness during aging follows a parabolic relationship with time. Regression analysis (time exponent, n) indicated that IMC growth kinetics is controlled by a diffusion mechanism. The results have important implications in the selection of high temperature solders used in high temperature applications.

  13. High temperature measurement by noise thermometry

    International Nuclear Information System (INIS)

    Decreton, M.C.

    1982-06-01

    Noise thermometry has received a lot of attention for measurements of temperatures in the high range around 1000-2000 deg. K. For these measurements, laboratory type experiments have been mostly performed. These have shown the interest of the technique when long term stability, high precision and insensibility to external conditions are concerned. This is particularly true for measurements in nuclear reactors where important drifts due to irradiation effects are experienced with other measurement techniques, as thermocouple for instance. Industrial noise thermometer experiments have not been performed extensively up to now. The subject of the present study is the development of a 1800 deg. K noise thermometer for nuclear applications. The measurement method is based on a generalized noise power approach. The rms noise voltage (Vsub(s)) and noise current (Isub(s)) are successively measured on the resistive sensor. The same quantities are also measured on a dummy short circuited probe (Vsub(d) and Isub(d)). The temperature is then deduced from these measured values by the following formula: cTsub(s) = (Vsub(s) 2 - Vsub(d) 2 )(Vsub(s)/Isub(s) - Vsub(d)/Isub(d)) - 1 , where c is a constant and Tsub(s) the absolute temperature of the sensor. This approach has the particular advantage of greatly reducing the sensibility to environmental perturbations on the leads and to the influence of amplifier noise sources. It also eliminates the necessity of resistance measurement and keeps the electronic circuits as simple as possible

  14. Development of Very High Temperature Reactor Technology

    International Nuclear Information System (INIS)

    Lee, Won Jae; Noh, J. M.; Kim, Y. H.

    2009-04-01

    For an efficient production of nuclear hydrogen, the VHTR (Very High Temperature Gas-cooled Reactor) of 950 .deg. C outlet temperature and the interfacing system for the hydrogen production are required. We have developed various evaluation technologies for the performance and safety of VHTR through the accomplishment of this project. First, to evaluate the performance of VHTR, a series of analyses has been performed such as core characteristics at 950 .deg. C, applicability of cooled-vessel, intermediate loop system and high temperature structural integrity. Through the analyses of major accidents such as HPCC and LPCC and the analysis of the risk/performance-informed method, VHTR safety evaluation has been also performed. In addition, various design analysis codes have been developed for a nuclear design, system loop design, system performance analysis, air-ingress accident analysis, fission product/tritium transport analysis, graphite structure seismic analysis and hydrogen explosion analysis, and they are being verified and validated through a lot of international collaborations

  15. High Pressure and Temperature Effects in Polymers

    Science.gov (United States)

    Bucknall, David; Arrighi, Valeria; Johnston, Kim; Condie, Iain

    Elastomers are widely exploited as the basis for seals in gas and fluid pipelines. The underlying behaviour of these elastomer at the high pressure, elevated temperatures they experience in operation is poorly understood. Consequently, the duty cycle of these materials is often deliberately limited to a few hours, and in order to prevent failure, production is stopped in order to change the seals in critical joints. The result is significant time lost due to bringing down production to change the seals as well as knock on financial costs. In order to address the fundamental nature of the elastomers at their intended operating conditions, we are studying the gas permeation behaviour of hydrogenated natural butyl rubber (HNBR) and fluorinated elastomers (FKM) at a high pressure and elevated temperature. We have developed a pressure system that permits gas permeation studies at gas pressures of up to 5000 psi and operating temperatures up to 150° C. In this paper, we will discuss the nature of the permeation behaviour at these extreme operating conditions, and how this relates to the changes in the polymer structure. We will also discuss the use of graphene-polymer thin layer coatings to modify the gas permeation behaviour of the elastomers.

  16. High temperature engineering research facilities and experiments in China

    International Nuclear Information System (INIS)

    Xu, Yuanhui; Liu, Meisheng; Yao, Huizhong; Ju, Huaiming

    1998-01-01

    June 14, 1995, the construction of a pebble bed type high temperature gas-cooled reactor (HTGR) started in China. It is a test reactor with 10 MW thermal power output (termed HTR- 10). The test reactor is located on the site of Institute of Nuclear Energy Technology (INET) of Tsinghua University in the northwest suburb of Beijing, about 40 km away from the city. Design of the HTR-10 test reactor represents the features of HTR-Modular design: 'side-by-side' arrangement, spherical fuel elements with 'multi-pass' loading scheme, completely passive decay heat removal, reactor shutdown systems in the side reflector, etc. However, in the HTR-10 design some modifications from the HTR-Module were made to satisfy Chinese conditions. For example, the steam generator is composed of a number of modular helical tubes with small diameter, pulse pneumatic discharging apparatus are used in the fuel handling system and step motor driving control rods are designed. These modifications would cause some uncertainty in our design. It is necessary to do engineering experiments to prove these new or modified ideas. Therefore, a program of engineering experiments for HTR-10 key technologies is being conducted at INET. The main aims of these engineering experiments are to verify the designed characteristics and performance of the components and systems, to feedback on design and to obtain operational experiences. Those engineering experiments are depressurization test of the hot gas duct at room temperature and operating pressure, performance test of the hot gas duct at operating helium temperature and pressure, performance test of the pulse pneumatic fuel handling system, test of the control rods driving apparatus, two phase flow stability test for the once through steam generator and cross mixture test at the bottom of the reactor core

  17. High temperature resistive phase transition in A15 high temperature superconductors

    International Nuclear Information System (INIS)

    Chu, C.W.; Huang, C.Y.; Schmidt, P.H.; Sugawara, K.

    1976-01-01

    Resistive measurements were made on A15 high temperature superconductors. Anomalies indicative of a phase transition were observed at 433 0 K in a single crystal Nb 3 Sn and at 485 0 K in an unbacked Nb 3 Ge sputtered thin film. Results are compared with the high temperature transmission electron diffraction studies of Nb 3 Ge films by Schmidt et al. A possible instability in the electron energy spectrum is discussed

  18. Permanent magnets composed of high temperature superconductors

    Science.gov (United States)

    Weinstein, Roy; Chen, In-Gann; Liu, Jay; Lau, Kwong

    1991-01-01

    A study of persistent, trapped magnetic field has been pursued with high-temperature superconducting (HTS) materials. The main effort is to study the feasibility of utilization of HTS to fabricate magnets for various devices. The trapped field, when not in saturation, is proportional to the applied field. Thus, it should be possible to replicate complicated field configurations with melt-textured YBa2Cu3O7 (MT-Y123) material, bypassing the need for HTS wires. Presently, materials have been developed from which magnets of 1.5 T, at 77 K, can be fabricated. Much higher field is available at lower operating temperature. Stability of a few percent per year is readily attainable. Results of studies on prototype motors and minimagnets are reported.

  19. Operational Modelling of High Temperature Electrolysis (HTE)

    International Nuclear Information System (INIS)

    Patrick Lovera; Franck Blein; Julien Vulliet

    2006-01-01

    Solid Oxide Fuel Cells (SOFC) and High Temperature Electrolysis (HTE) work on two opposite processes. The basic equations (Nernst equation, corrected by a term of over-voltage) are thus very similar, only a few signs are different. An operational model, based on measurable quantities, was finalized for HTE process, and adapted to SOFCs. The model is analytical, which requires some complementary assumptions (proportionality of over-tensions to the current density, linearization of the logarithmic term in Nernst equation). It allows determining hydrogen production by HTE using a limited number of parameters. At a given temperature, only one macroscopic parameter, related to over-voltages, is needed for adjusting the model to the experimental results (SOFC), in a wide range of hydrogen flow-rates. For a given cell, this parameter follows an Arrhenius law with a satisfactory precision. The prevision in HTE process is compared to the available experimental results. (authors)

  20. Creep resistant high temperature martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Jablonski, Paul D.; Cowen, Christopher J.

    2017-01-31

    The disclosure provides a creep resistant alloy having an overall composition comprised of iron, chromium, molybdenum, carbon, manganese, silicon, nickel, vanadium, niobium, nitrogen, tungsten, cobalt, tantalum, boron, copper, and potentially additional elements. In an embodiment, the creep resistant alloy has a molybdenum equivalent Mo(eq) from 1.475 to 1.700 wt. % and a quantity (C+N) from 0.145 to 0.205. The overall composition ameliorates sources of microstructural instability such as coarsening of M.sub.23C.sub.6carbides and MX precipitates, and mitigates or eliminates Laves and Z-phase formation. A creep resistant martensitic steel may be fabricated by preparing a melt comprised of the overall composition followed by at least austenizing and tempering. The creep resistant alloy exhibits improved high-temperature creep strength in the temperature environment of around 650.degree. C.

  1. Materials for advanced high temperature reactors

    International Nuclear Information System (INIS)

    Graham, L.W.

    1976-01-01

    The results recently obtained from the Dragon program are presented to illustrate materials behavior: (a) effect of temperature on oxidation and carburisation in HTR helium (variation in oxide depth and in C content of AISI 321 after 5000 hours in HTR helium; effect of temperature on surface scale formation in the γ' strengthened alloys Nimonic 80A and 713LC); (b) effect of alloy composition on oxidation and carburisation behavior (influence of Nb and Ti on the corrosion of austenitic steels; influence of Ti and Al in IN-102; weight gain of cast high Ni alloys); (c) effect of environment on creep strength (results of tests for hastelloy X, grade I inconel 625, grade II inconel 625 and inconel 617 in He and air between 750 and 800 0 C)

  2. High Temperature Polymer Electrolyte Fuel Cells

    DEFF Research Database (Denmark)

    Fleige, Michael

    This thesis presents the development and application of electrochemical half-cell setups to study the catalytic reactions taking place in High Temperature Polymer Electrolyte Fuel Cells (HTPEM-FCs): (i) a pressurized electrochemical cell with integrated magnetically coupled rotating disk electrode...... oxidation of ethanol is in principle a promising concept to supply HTPEM-FCs with a sustainable and on large scale available fuel (ethanol from biomass). However, the intermediate temperature tests in the GDE setup show that even on Pt-based catalysts the reaction rates become first significant...... at potentials, which approach the usual cathode potentials of HTPEM-FCs. Therefore, it seems that H3PO4-based fuel cells are not much suited to efficiently convert ethanol in accordance with findings in earlier research papers. Given that HTPEM-FCs can tolerate CO containing reformate gas, focusing research...

  3. FY16 ASME High Temperature Code Activities

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, M. J. [Chromtech Inc., Oak Ridge, TN (United States); Jetter, R. I. [R. I Jetter Consulting, Pebble Beach, CA (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    One of the objectives of the ASME high temperature Code activities is to develop and validate both improvements and the basic features of Section III, Division 5, Subsection HB, Subpart B (HBB). The overall scope of this task is to develop a computer program to be used to assess whether or not a specific component under specified loading conditions will satisfy the elevated temperature design requirements for Class A components in Section III, Division 5, Subsection HB, Subpart B (HBB). There are many features and alternative paths of varying complexity in HBB. The initial focus of this task is a basic path through the various options for a single reference material, 316H stainless steel. However, the program will be structured for eventual incorporation all the features and permitted materials of HBB. Since this task has recently been initiated, this report focuses on the description of the initial path forward and an overall description of the approach to computer program development.

  4. Creep resistant high temperature martensitic steel

    Science.gov (United States)

    Hawk, Jeffrey A.; Jablonski, Paul D.; Cowen, Christopher J.

    2015-11-13

    The disclosure provides a creep resistant alloy having an overall composition comprised of iron, chromium, molybdenum, carbon, manganese, silicon, nickel, vanadium, niobium, nitrogen, tungsten, cobalt, tantalum, boron, and potentially additional elements. In an embodiment, the creep resistant alloy has a molybdenum equivalent Mo(eq) from 1.475 to 1.700 wt. % and a quantity (C+N) from 0.145 to 0.205. The overall composition ameliorates sources of microstructural instability such as coarsening of M.sub.23C.sub.6 carbides and MX precipitates, and mitigates or eliminates Laves and Z-phase formation. A creep resistant martensitic steel may be fabricated by preparing a melt comprised of the overall composition followed by at least austenizing and tempering. The creep resistant alloy exhibits improved high-temperature creep strength in the temperature environment of around 650.degree. C.

  5. Effect of bed configuration on pebble flow uniformity and stagnation in the pebble bed reactor

    International Nuclear Information System (INIS)

    Gui, Nan; Yang, Xingtuan; Tu, Jiyuan; Jiang, Shengyao

    2014-01-01

    Highlights: • Pebble flow uniformity and stagnation characteristics are very important for HTR-PM. • Arc- and brachistochrone-shaped configuration effects are studied by DEM simulation. • Best bed configurations with uniform flow and no stagnated pebbles are suggested. • Detailed quantified characteristics of bed configuration effects are shown for explanation. - Abstract: Pebble flow uniformity and stagnation characteristics are very important for the design of pebble bed high temperature gas-cooled reactor. Pebble flows inside some specifically designed contraction configurations of pebble bed are studied by discrete element method. The results show the characteristics of stagnation rates, recycling rates, radial distribution of pebble velocity and residence time. It is demonstrated clearly that the bed with a brachistochrone-shaped configuration achieves optimum levels of flow uniformity and recycling rate concentration, and almost no pebbles are stagnated in the bed. Moreover, the optimum choice among the arc-shaped bed configurations is demonstrated too. Detailed information shows the quantified characteristics of bed configuration effects on flow uniformity. In addition, a good design of the pebble bed configuration is suggested

  6. High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Turnquist, Norman [GE Global Research, Munchen (Germany); Qi, Xuele [GE Global Research, Munchen (Germany); Raminosoa, Tsarafidy [GE Global Research, Munchen (Germany); Salas, Ken [GE Global Research, Munchen (Germany); Samudrala, Omprakash [GE Global Research, Munchen (Germany); Shah, Manoj [GE Global Research, Munchen (Germany); Van Dam, Jeremy [GE Global Research, Munchen (Germany); Yin, Weijun [GE Global Research, Munchen (Germany); Zia, Jalal [GE Global Research, Munchen (Germany)

    2013-12-20

    This report summarizes the progress made during the April 01, 2010 – December 30, 2013 period under Cooperative Agreement DE-EE0002752 for the U.S. Department of Energy entitled “High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems.” The overall objective of this program is to advance the technology for well fluids lifting systems to meet the foreseeable pressure, temperature, and longevity needs of the Enhanced Geothermal Systems (EGS) industry for the coming ten years. In this program, lifting system requirements for EGS wells were established via consultation with industry experts and site visits. A number of artificial lift technologies were evaluated with regard to their applicability to EGS applications; it was determined that a system based on electric submersible pump (ESP) technology was best suited to EGS. Technical barriers were identified and a component-level technology development program was undertaken to address each barrier, with the most challenging being the development of a power-dense, small diameter motor that can operate reliably in a 300°C environment for up to three years. Some of the targeted individual component technologies include permanent magnet motor construction, high-temperature insulation, dielectrics, bearings, seals, thrust washers, and pump impellers/diffusers. Advances were also made in thermal management of electric motors. In addition to the overall system design for a full-scale EGS application, a subscale prototype was designed and fabricated. Like the full-scale design, the subscale prototype features a novel “flow-through-the-bore” permanent magnet electric motor that combines the use of high temperature materials with an internal cooling scheme that limits peak internal temperatures to <330°C. While the full-scale high-volume multi-stage pump is designed to lift up to 80 kg/s of process water, the subscale prototype is based on a production design that can pump 20 kg/s and has been modified

  7. Climate effect of an integrated wheat production and bioenergy system with Low Temperature Circulating Fluidized Bed gasifier

    International Nuclear Information System (INIS)

    Sigurjonsson, Hafthor Ægir; Elmegaard, Brian; Clausen, Lasse Røngaard; Ahrenfeldt, Jesper

    2015-01-01

    Highlights: • Wheat straw removal from agricultural system has considerable GWP effect. • Changing the carbon conv. in the gasifier to 0.8–0.86 mitigates those effects. • Considerable difference is between sequestration potential of straw and biochar. • Lowering the carbon conversion improves GWP, but depends on subst. technology. - Abstract: When removing biomass residues from the agriculture for bioenergy utilization, the nutrients and carbon stored within these “residual resources” are removed as-well. To mitigate these issues the energy industry must try to conserve and not destroy the nutrients. The paper analyses a novel integration between the agricultural system and the energy system through the Low Temperature Circulating Fluidized Bed (LT-CFB) gasifier from the perspective of wheat grain production and electricity generation using wheat straw, where the effects of removing the straw from the agricultural system are assessed along with the effects of recycling the nutrients and carbon back to the agricultural system. The methods used to assess the integration was Life Cycle Assessment (LCA) with IPCC’s 2013 100 year global warming potential (GWP) as impact assessment method. The boundary was set from cradle to gate with two different functional units, kg grain and kW h electricity produced in Zealand, Denmark. Two cases were used in the analysis: 1. nutrient balances are regulated by mineral fertilization and 2. the nutrient balances are regulated by yield. The analysis compare three scenarios of gasifier operation based on carbon conversion to two references, no straw removal and straw combustion. The results show that the climate effect of removing the straws are mitigated by the carbon soil sequestration with biochar, and electricity and district heat substitution. Maximum biochar production outperforms maximum heat and power generation for most substituted electricity and district heating scenarios. Irrespective of the substituted

  8. High-temperature superconductors make major progress

    CERN Multimedia

    CERN Bulletin

    2014-01-01

    This month's Nature Materials featured an important breakthrough for high-temperature superconductors. A new method has been found for processing Bi-2212 high-temperature superconducting round wire in order to drastically increase its critical current density. The result confirms that this conductor is a serious candidate for future very-high-field magnets.   This image shows the cross-section of two Bi-2212 wires. The bottom wire has less leakage and void porosity due to a heat treatment done at an overpressure of 100 bar - about 100 times the pressure used to produce the top wire (image from [Nature Materials, Vol. 13 (2014), 10.1038/nmat3887]). The workhorse for building superconducting accelerator magnets has been, so far, the Niobium-Titanium (Nb-Ti) alloy superconductor. But with Nb-Ti having reached its full potential, other conductors must be used to operate in higher magnetic fields beyond those reached with the LHC magnets. Today, the intermetallic Niobium-Tin (Nb3Sn) is th...

  9. Transient quenching of superheated debris beds during bottom reflood

    International Nuclear Information System (INIS)

    Tutu, N.K.; Ginsberg, T.; Klein, J.; Schwarz, C.E.; Klages, J.

    1984-01-01

    The experimental data suggest that for small liquid supply rate and low initial particle temperature, the bed quench process is a one-dimensional frontal phenomenon. The bed heat flux is constant during most of the duration of the quench period. The range of conditions which display one-dimensional frontal cooling characteristics is identified as the deep bed regime of bed quenching, and a limiting mathematical model was developed to describe the observed behavior. For large liquid supply rate and high initial bed temperature, the bed quench process is a complex phenomenon. Under these conditions, the bed heat flux displays a nonuniform time dependence. In order to characterize this shallow bed regime, it was necessary to develop a detailed transient model of the coolant-debris interaction. This model, while developed for the shallow bed regime, also applies to the deep bed regime. Numerical computations clearly demonstrate the importance of developing a general reliable model for the solid-fluid heat transfer coefficients

  10. High temperature creep-fatigue design

    International Nuclear Information System (INIS)

    Tavassoli, A. A. F.; Fournier, B.; Sauzay, M.

    2010-01-01

    Generation IV fission and future fusion reactors envisage development of more efficient high temperature concepts where materials performances are key to their success. This paper examines different types of high temperature creep-fatigue interactions and their implications on design rules for the structural materials retained in both programmes. More precisely, the paper examines current status of design rules for the stainless steel type 316L(N), the conventional Modified 9Cr-1Mo martensitic steel and the low activation Eurofer steel. Results obtained from extensive high temperature creep, fatigue and creep-fatigue tests performed on these materials and their welded joints are presented. These include sequential creep-fatigue and relaxation creep-fatigue tests with hold times in tension, in compression or in both. Effects of larger plastic deformations on fatigue properties are studied through cyclic creep tests or fatigue tests with extended hold time in creep. In most cases, mechanical test results are accompanied with microstructural and fractographic observations. In the case of martensitic steels, the effect of oxidation is examined by performing creep-fatigue tests on identical specimens in vacuum. Results obtained are analyzed and their implications on design allowable and creep-fatigue interaction diagrams are presented. While reasonable confidence is found in predicting creep-fatigue damage through existing code procedures for austenitic stainless steels, effects of cyclic softening and coarsening of microstructure of martensitic steels throughout the fatigue life on materials properties need to be taken into account for more precise damage calculations. In the long-term, development of ferritic/martensitic steels with stable microstructure, such as ODS steels, is proposed. (authors)

  11. High temperature creep-fatigue design

    Energy Technology Data Exchange (ETDEWEB)

    Tavassoli, A. A. F.; Fournier, B.; Sauzay, M. [CEA Saclay, DEN DMN, F-91191 Gif Sur Yvette (France)

    2010-07-01

    Generation IV fission and future fusion reactors envisage development of more efficient high temperature concepts where materials performances are key to their success. This paper examines different types of high temperature creep-fatigue interactions and their implications on design rules for the structural materials retained in both programmes. More precisely, the paper examines current status of design rules for the stainless steel type 316L(N), the conventional Modified 9Cr-1Mo martensitic steel and the low activation Eurofer steel. Results obtained from extensive high temperature creep, fatigue and creep-fatigue tests performed on these materials and their welded joints are presented. These include sequential creep-fatigue and relaxation creep-fatigue tests with hold times in tension, in compression or in both. Effects of larger plastic deformations on fatigue properties are studied through cyclic creep tests or fatigue tests with extended hold time in creep. In most cases, mechanical test results are accompanied with microstructural and fractographic observations. In the case of martensitic steels, the effect of oxidation is examined by performing creep-fatigue tests on identical specimens in vacuum. Results obtained are analyzed and their implications on design allowable and creep-fatigue interaction diagrams are presented. While reasonable confidence is found in predicting creep-fatigue damage through existing code procedures for austenitic stainless steels, effects of cyclic softening and coarsening of microstructure of martensitic steels throughout the fatigue life on materials properties need to be taken into account for more precise damage calculations. In the long-term, development of ferritic/martensitic steels with stable microstructure, such as ODS steels, is proposed. (authors)

  12. Variations in pore characteristics in high volatile bituminous coals: Implications for coal bed gas content

    Science.gov (United States)

    Mastalerz, Maria; Drobniak, A.; Strapoc, D.; Solano-Acosta, W.; Rupp, J.

    2008-01-01

    The Seelyville Coal Member of the Linton Formation (Pennsylvanian) in Indiana was studied to: 1) understand variations in pore characteristics within a coal seam at a single location and compare these variations with changes occurring between the same coal at different locations, 2) elaborate on the influence of mineral-matter and maceral composition on mesopore and micropore characteristics, and 3) discuss implications of these variations for coal bed gas content. The coal is high volatile bituminous rank with R0 ranging from 0.57% to 0.60%. BET specific surface areas (determined by nitrogen adsorption) of the coals samples studied range from 1.8 to 22.9??m2/g, BJH adsorption mesopore volumes from 0.0041 to 0.0339??cm3/g, and micropore volumes (determined by carbon dioxide adsorption) from 0.0315 to 0.0540??cm3/g. The coals that had the largest specific surface areas and largest mesopore volumes occur at the shallowest depths, whereas the smallest values for these two parameters occur in the deepest coals. Micropore volumes, in contrast, are not depth-dependent. In the coal samples examined for this study, mineral-matter content influenced both specific surface area as well as mesopore and micropore volumes. It is especially clear in the case of micropores, where an increase in mineral-matter content parallels the decrease of micropore volume of the coal. No obvious relationships were observed between the total vitrinite content and pore characteristics but, after splitting vitrinite into individual macerals, we see that collotelinite influences both meso- and micropore volume positively, whereas collodetrinite contributes to the reduction of mesopore and micropore volumes. There are large variations in gas content within a single coal at a single location. Because of this variability, the entire thickness of the coal must be desorbed in order to determine gas content reliably and to accurately calculate the level of gas saturation. ?? 2008 Elsevier B.V. All

  13. Investigation of gadolinium monophosphide at high temperatures

    International Nuclear Information System (INIS)

    Gordienko, S.P.; Gol'nik, V.F.; Mironov, K.E.

    1982-01-01

    Gadolinium monophosphide has been studied in vacuum at high temperatures using mass-spectrometric, chemical, X-ray phase and derivatographical analyses. It is established that gadolinium monophosphide at 2080-2465 K dissociates into atomic gadolinium, phosphorus and, P 2 molecules. According to Vant-Hoff and Gibbs-Helmholtz equations standard enthalpy of atomization ΔHsub(at) deg (298)=1027.3 kJ/mol and of formation ΔHsub(f) deg (298)=313.8 kJ/mol of gadolinium monophosphide are determined

  14. Encapsulation of high temperature molten salts

    Science.gov (United States)

    Oxley, James D.; Mathur, Anoop Kumar

    2017-05-16

    The present disclosure relates to a method of encapsulating microcapsules containing relatively high temperature phase change materials and the microcapsules so produced. The microcapsules are coated with an inorganic binder, film former and an inorganic filler. The microcapsules may include a sacrificial layer that is disposed between the particle and the coating. The microcapsules may also include an inner coating layer, sacrificial layer and outer coating layer. The microcapsules are particularly useful for thermal energy storage in connection with, e.g., heat collected from concentrating solar collectors.

  15. High Temperature Materials Laboratory third annual report

    Energy Technology Data Exchange (ETDEWEB)

    Tennery, V.J.; Foust, F.M.

    1990-12-01

    The High Temperature Materials Laboratory has completed its third year of operation as a designated DOE User Facility at the Oak Ridge National Laboratory. Growth of the user program is evidenced by the number of outside institutions who have executed user agreements since the facility began operation in 1987. A total of 88 nonproprietary agreements (40 university and 48 industry) and 20 proprietary agreements (1 university, 19 industry) are now in effect. Sixty-eight nonproprietary research proposals (39 from university, 28 from industry, and 1 other government facility) and 8 proprietary proposals were considered during this reporting period. Research projects active in FY 1990 are summarized.

  16. Experimental needs of high temperature concrete

    International Nuclear Information System (INIS)

    Chern, J.C.; Marchertas, A.H.

    1985-01-01

    The needs of experimental data on concrete structures under high temperature, ranging up to about 370 0 C for operating reactor conditions and to about 900 0 C and beyond for hypothetical accident conditions, are described. This information is required to supplement analytical methods which are being implemented into the finite element code TEMP-STRESS to treat reinforced concrete structures. Recommended research ranges from material properties of reinforced/prestressed concrete, direct testing of analytical models used in the computer codes, to investigations of certain aspects of concrete behavior, the phenomenology of which is not well understood. 10 refs

  17. Modeling forces in high-temperature superconductors

    International Nuclear Information System (INIS)

    Turner, L. R.; Foster, M. W.

    1997-01-01

    We have developed a simple model that uses computed shielding currents to determine the forces acting on a high-temperature superconductor (HTS). The model has been applied to measurements of the force between HTS and permanent magnets (PM). Results show the expected hysteretic variation of force as the HTS moves first toward and then away from a permanent magnet, including the reversal of the sign of the force. Optimization of the shielding currents is carried out through a simulated annealing algorithm in a C++ program that repeatedly calls a commercial electromagnetic software code. Agreement with measured forces is encouraging

  18. Multichannel euv spectroscopy of high temperature plasmas

    International Nuclear Information System (INIS)

    Fonck, R.J.

    1983-11-01

    Spectroscopy of magnetically confined high temperature plasmas in the visible through x-ray spectral ranges deals primarily with the study of impurity line radiation or continuum radiation. Detailed knowledge of absolute intensities, temporal behavior, and spatial distributions of the emitted radiation is desired. As tokamak facilities become more complex, larger, and less accessible, there has been an increased emphasis on developing new instrumentation to provide such information in a minimum number of discharges. The availability of spatially-imaging detectors for use in the vacuum ultraviolet region (especially the intensified photodiode array) has generated the development of a variety of multichannel spectrometers for applications on tokamak facilities

  19. High-temperature superconducting current leads

    Science.gov (United States)

    Hull, J. R.

    1992-07-01

    The use of high-temperature superconductors (HTSs) for current leads to deliver power to devices at liquid helium temperature is near commercial realization. The use of HTSs in this application has the potential to reduce refrigeration requirements and helium boiloff to values significantly lower than the theoretical best achievable with conventional leads. Considerable advantage is achieved by operating these leads with an intermediate temperature heat sink. The HTS part of the lead can be made from pressed and sintered powder. Powder-in-tube fabrication is also possible, however, the normal metal part of the lead acts as a thermal short and cannot provide much stabilization without increasing the refrigeration required. Lead stability favors designs with low current density. Such leads can be manufactured with today's technology, and lower refrigeration results from the same allowable burnout time. Higher current densities result in lower boiloff for the same lead length, but bumout times can be very short. In comparing experiment to theory, the density of helium vapor needs to be accounted for in calculating the expected boiloff. For very low-loss leads, two-dimensional heat transfer and the state of the dewar near the leads may play a dominant role in lead performance.

  20. The moon as a high temperature condensate.

    Science.gov (United States)

    Anderson, D. L.

    1973-01-01

    The accretion during condensation mechanism, if it occurs during the early over-luminous stage of the sun, can explain the differences in composition of the terrestrial planets and the moon. An important factor is the variation of pressure and temperature with distance from the sun, and in the case of the moon and captured satellites of other planets, with distance from the median plane. Current estimates of the temperature and pressure in the solar nebula suggest that condensation will not be complete in the vicinity of the terrestrial planets, and that depending on location, iron, magnesium silicates and the volatiles will be at least partially held in the gaseous phase and subject to separation from the dust by solar wind and magnetic effects associated with the transfer of angular momentum just before the sun joins the Main Sequence. Many of the properties of the moon, including the 'enrichment' in Ca, Al, Ti, U, Th, Ba, Sr and the REE and the 'depletion' in Fe, Rb, K, Na and other volatiles can be understood if the moon represents a high temperature condensate from the solar nebula.