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Sample records for bed htgr cores

  1. Gamma spectroscopic examination of Peach Bottom HTGR core components

    Energy Technology Data Exchange (ETDEWEB)

    Holzgraf, J.F.; McCord, F.; Wallroth, C.F.

    1978-04-01

    During discharge of Core 2 from the Peach Bottom High-Temperature Gas-Cooled Reactor (HTGR), 55 driver elements, 21 test elements, three reflector elements, and one control rod with sleeve were axially gamma scanned with a high-resolution Ge(Li) detector. The purpose of the exercise was to determine fission product distributions for use in burnup calculations, power profile determinations, and fission product release and redistribution studies. The results showed that the predicted and measured burnups had a +-7 percent root mean square deviation on an element-to-element basis and were within +-0.7 percent (1 sigma) on a core average basis. The element-to-element variation of +-7 percent is within the generally stated +-3 percent to 8 percent accuracy for nuclear predictions.

  2. Review of fatigue criteria development for HTGR core supports

    Energy Technology Data Exchange (ETDEWEB)

    Ho, F.H.; Vollman, R.E.

    1979-10-01

    Fatigue criteria for HTGR core support graphite structure are presented. The criteria takes into consideration the brittle nature of the material, and emphasizes the probabilistic approach in the treatment of strength data. The stress analysis is still deterministic. The conventional cumulative damage approach is adopted here. A specified minimum S-N curve is defined as the curve with 99% probability of survival at a 95% confidence level to accommodate random variability of the material strength. A constant life diagram is constructed to reconcile the effect of mean stress. The linear damage rule is assumed to account for the effect of random cycles. An additional factor of safety of three on cycles is recommended. The uniaxial S-N curve is modified in the medium-to-high cycle range (> 2 x 10/sup 3/ cycles) for mutiaxial fatigue effects.

  3. COCO: a computer program for seismic analysis of a single column of the HTGR core

    Energy Technology Data Exchange (ETDEWEB)

    Rickard, N.D.

    1978-02-01

    The document serves as a user's manual and theoretical manual for the COCO code. COCO is a nonlinear numerical integration program designed to analyze a single column of the HTGR core for seismic excitation. Output of the code includes dowel forces, collision forces, and a time history of the motion of the blocks.

  4. Further HTGR core support structure reliability studies. Interim report No. 1

    Energy Technology Data Exchange (ETDEWEB)

    Platus, D.L.

    1976-01-13

    Results of a continuing effort to investigate high temperature gas cooled reactor (HTGR) core support structure reliability are described. Graphite material and core support structure component physical, mechanical and strength properties required for the reliability analysis are identified. Also described are experimental and associated analytical techniques for determining the required properties, a procedure for determining number of tests required, properties that might be monitored by special surveillance of the core support structure to improve reliability predictions, and recommendations for further studies. Emphasis in the study is directed towards developing a basic understanding of graphite failure and strength degradation mechanisms; and validating analytical methods for predicting strength and strength degradation from basic material properties.

  5. IAEA CRP on HTGR Uncertainties in Modeling: Assessment of Phase I Lattice to Core Model Uncertainties

    Energy Technology Data Exchange (ETDEWEB)

    Rouxelin, Pascal Nicolas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Strydom, Gerhard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    Best-estimate plus uncertainty analysis of reactors is replacing the traditional conservative (stacked uncertainty) method for safety and licensing analysis. To facilitate uncertainty analysis applications, a comprehensive approach and methodology must be developed and applied. High temperature gas cooled reactors (HTGRs) have several features that require techniques not used in light-water reactor analysis (e.g., coated-particle design and large graphite quantities at high temperatures). The International Atomic Energy Agency has therefore launched the Coordinated Research Project on HTGR Uncertainty Analysis in Modeling to study uncertainty propagation in the HTGR analysis chain. The benchmark problem defined for the prismatic design is represented by the General Atomics Modular HTGR 350. The main focus of this report is the compilation and discussion of the results obtained for various permutations of Exercise I 2c and the use of the cross section data in Exercise II 1a of the prismatic benchmark, which is defined as the last and first steps of the lattice and core simulation phases, respectively. The report summarizes the Idaho National Laboratory (INL) best estimate results obtained for Exercise I 2a (fresh single-fuel block), Exercise I 2b (depleted single-fuel block), and Exercise I 2c (super cell) in addition to the first results of an investigation into the cross section generation effects for the super-cell problem. The two dimensional deterministic code known as the New ESC based Weighting Transport (NEWT) included in the Standardized Computer Analyses for Licensing Evaluation (SCALE) 6.1.2 package was used for the cross section evaluation, and the results obtained were compared to the three dimensional stochastic SCALE module KENO VI. The NEWT cross section libraries were generated for several permutations of the current benchmark super-cell geometry and were then provided as input to the Phase II core calculation of the stand alone neutronics Exercise

  6. Effect of steam corrosion on core post strength loss: I. Low, chronic steam ingress rates. [HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Wichner, R.P.

    1976-10-01

    The purpose of the study was to assess the effect of chronic, low levels of steam ingress into the primary system of the HTGR on the corrosion, and consequent strength loss of the core support posts. The assessment proceeded through the following three steps: (1) The impurity composition in the primary system was estimated as a function of a range of steady ingress rates of from 0.001 to 1.0 g/sec, both by means of an analysis of the Dragon steam ingress experiment and a computer code, TIMOX, which treats the primary system as a well-mixed pot. (2) The core post burnoffs which result from 40-year exposures to these determined impurity atmospheres were then estimated using a corrosion rate expression derived from published ATJ-graphite corrosion rate data. Burnoffs were determined for both the core posts at the nominal and the maximum sustained temperature, estimated to be 90/sup 0/C above nominal. (3) The final step involved assessment of the degree of strength loss resulting from the estimated burnoffs. An empirical equation was developed for this purpose which compares reasonably well with strength loss data for a number of different graphites and specimen geometries.

  7. Properties of unirradiated HTGR core support and permanent side reflector graphites: PGX, HLM, 2020, and H-440N

    Energy Technology Data Exchange (ETDEWEB)

    Engle, G.B.

    1977-05-01

    Candidate materials for HTGR core supports and permanent side reflectors--graphite grades 2020 (Stackpole Carbon Company), H-440N (Great Lakes Carbon Corporation), PGX (Union Carbide Corporation), and HLM (Great Lakes Carbon Corporation)--are described and property data are presented. Properties measured are bulk density; tensile properties including ultimate strength, modulus of elasticity, and strain at fracture; flexural strength; compressive properties including ultimate strength, modulus of elasticity, and strain at fracture; and chemical impurity content.

  8. Optimization of MOX Fuel Cycles in Pebble Bed HTGR%球床式高温气冷堆MOX燃料循环优化

    Institute of Scientific and Technical Information of China (English)

    位金锋; 李富; 孙玉良

    2013-01-01

    与压水堆相比,球床式高温气冷堆能在堆芯结构不做明显改变的情况下采用全堆芯装载混合氧化物(MOX)燃料元件.基于250 MW球床模块式高温气冷堆堆芯结构,设计了4种球床式高温气冷堆下MOX燃料循环方式,包括铀钚混合的燃料球和独立的钚球与铀球混合装载的等效方式,采用高温气冷堆设计程序VSOP进行分析,比较了初装堆的有效增殖因数、燃料元件在堆芯内滞留时间、卸料燃耗、温度系数等主要物理特性.结果表明:采用纯铀和纯钚两种分离燃料球且铀燃料球循环时间更长的方案,平均卸料燃耗较高,总体性能较其他循环方式优越.%Compared with light water reactor (LWR),the pebble bed high temperature gas-cooled reactor (HTGR) is able to operate in a full mixed oxide (MOX) fuelled core without significant change to core structure design. Based on a reference design of 250 MW pebble bed HTGR, four MOX fuel cycles were designed and evaluated by VSOP program package, including the mixed Pu-U fuel pebbles and mixed loading of separate Pu-pebbles and U-pebbles. Some important physics features were investigated and compared for these four cycles, such as the effective multiplication factor of initial core, the pebble residence time, discharge burnup, and temperature coefficients. Preliminary results show that the overall performance of one case is superior to other equivalent MOX fuel cycles on condition that uranium fuel elements and plutonium fuel elements are separated as the different fuel pebbles and that the uranium fuel elements are irradiated longer in the core than the plutonium fuel elements, and the average discharge burnup of this case is also higher than others.

  9. INVESTIGATION ON THERMAL-FLOW CHARACTERISTICS OF HTGR CORE USING THERMIX-KONVEK MODULE AND VSOP'94 CODE

    Directory of Open Access Journals (Sweden)

    Sudarmono Sudarmono

    2015-03-01

    Full Text Available The failure of heat removal system of water-cooled reactor such as PWR in Three Mile Islands and Fukushima Daiichi BWR makes nuclear society starting to consider the use of high temperature gas-cooled reactor (HTGR. Reactor Physics and Technology Division – Center for Nuclear Reactor Safety and Technology  (PTRKN has tasks to perform research and development on the conceptual design of cogeneration gas cooled reactor with medium power level of 200 MWt. HTGR is one of nuclear energy generation system, which has high energy efficiency, and has high and clean inherent safety level. The geometry and structure of the HTGR200 core are designed to produce the output of helium gas coolant temperature as high as 950 °C to be used for hydrogen production and other industrial processes in co-generative way. The output of very high temperature helium gas will cause thermal stress on the fuel pebble that threats the integrity of fission product confinement. Therefore, it is necessary to perform thermal-flow evaluation to determine the temperature distribution in the graphite and fuel pebble in the HTGR core. The evaluation was carried out by Thermix-Konvek module code that has been already integrated into VSOP'94 code. The HTGR core geometry was done using BIRGIT module code for 2-D model (RZ model with 5 channels of pebble flow in active core in the radial direction. The evaluation results showed that the highest and lowest temperatures in the reactor core are 999.3 °C and 886.5 °C, while the highest temperature of TRISO UO2 is 1510.20 °C in the position (z= 335.51 cm; r=0 cm. The analysis done based on reactor condition of 120 kg/s of coolant mass flow rate, 7 MPa of pressure and 200 MWth of power. Compared to the temperature distribution resulted between VSOP’94 code and fuel temperature limitation as high as 1600 oC, there is enough safety margin from melting or disintegrating. Keywords: Thermal-Flow, VSOP’94, Thermix-Konvek, HTGR, temperature

  10. Uncertainty and Sensitivity Analyses of a Pebble Bed HTGR Loss of Cooling Event

    Directory of Open Access Journals (Sweden)

    Gerhard Strydom

    2013-01-01

    Full Text Available The Very High Temperature Reactor Methods Development group at the Idaho National Laboratory identified the need for a defensible and systematic uncertainty and sensitivity approach in 2009. This paper summarizes the results of an uncertainty and sensitivity quantification investigation performed with the SUSA code, utilizing the International Atomic Energy Agency CRP 5 Pebble Bed Modular Reactor benchmark and the INL code suite PEBBED-THERMIX. Eight model input parameters were selected for inclusion in this study, and after the input parameters variations and probability density functions were specified, a total of 800 steady state and depressurized loss of forced cooling (DLOFC transient PEBBED-THERMIX calculations were performed. The six data sets were statistically analyzed to determine the 5% and 95% DLOFC peak fuel temperature tolerance intervals with 95% confidence levels. It was found that the uncertainties in the decay heat and graphite thermal conductivities were the most significant contributors to the propagated DLOFC peak fuel temperature uncertainty. No significant differences were observed between the results of Simple Random Sampling (SRS or Latin Hypercube Sampling (LHS data sets, and use of uniform or normal input parameter distributions also did not lead to any significant differences between these data sets.

  11. Gas-Cooled Reactor Programs annual progress report for period ending December 31, 1973. [HTGR fuel reprocessing, fuel fabrication, fuel irradiation, core materials, and fission product distribution; GCFR fuel irradiation and steam generator modeling

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.; Coobs, J.H.; Lotts, A.L.

    1976-04-01

    Progress is summarized in studies relating to HTGR fuel reprocessing, refabrication, and recycle; HTGR fuel materials development and performance testing; HTGR PCRV development; HTGR materials investigations; HTGR fuel chemistry; HTGR safety studies; and GCFR irradiation experiments and steam generator modeling.

  12. HTGR Fuel performance basis

    Energy Technology Data Exchange (ETDEWEB)

    Shamasundar, B.I.; Stansfield, O.M.; Jensen, D.D.

    1982-05-01

    The safety characteristics of the high-temperature gas-cooled reactor (HTGR) during normal and accident conditions are determined in part by HTGR fuel performance. During normal operation, less than 0.1% fuel failure occurs, primarily from defective particles. This low fuel failure fraction limits circulating activity to acceptable levels. During severe accidents, the radiological consequence is influenced by high-temperature fuel particle behavior. An empirical fuel failure model, supported by recent experimental data, is presented. The onset of significant fuel particle failure occurs at temperatures in excess of 1600/sup 0/C, and complete fuel failure occurs at 2660/sup 0/C. This indicates that the fuel is more retentive at higher temperatures than previously assumed. The more retentive nature of the fuel coupled with the high thermal capacitance of the core results in slow release of fission products from the core during severe accidents.

  13. Demonstration tests for HTGR fuel elements and core components with test sections in HENDEL

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Yoshiaki; Hino, Ryutaro; Inagaki, Yoshiyuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1995-03-01

    In the fuel stack test section (T{sub 1}) of the Helium Engineering Demonstration Loop (HENDEL), thermal and hydraulic performances of helium gas flows through a fuel rod channel and a fuel stack have been investigated for the High-Temperature Engineering Test Reactor (HTTR) core thermal design. The test data showed that the turbulent characteristics appearing in the Reynolds number above 2000: no typical behavior in the transition zone, and friction factors and heat transfer coefficients in the fuel channel were found to be higher than those in a smooth annular channel. Heat transfer behavior of gas flow in a fuel element channel with blockage and cross-flow through a gap between upper and lower fuel elements stacked was revealed using the mock-up models. On the other hand, demonstration tests have been performed to verify thermal and hydraulic characteristics and structural integrity related to the core bottom structure using a full-scale test facility named as the in-core structure test section (T{sub 2}). The sealing performance test revealed that the leakage of low-temperature helium gas through gaps between the permanent reflector blocks to the core was very low level compared with the HTTR design value and no change of the leakage flow rate were observed after a long term operation. The heat transfer tests including thermal transient at shutdown of gas circulators verified good insulating performance of core insulation structures in the core bottom structure and the hot gas duct; the temperature of the metal portion of these structure was below the design value. Examination of the thermal mixing characteristics indicated that the mixing of the hot helium gas started at a hot plenum and finished completely at downstream of the outlet hot gas duct. The present results obtained from these demonstration tests have been practically applied to the detailed design works and licensing procedures of the HTTR. (J.P.N.) 92 refs.

  14. Core Physics of Pebble Bed High Temperature Nuclear Reactors

    NARCIS (Netherlands)

    Auwerda, G.J.

    2014-01-01

    To more accurately predict the temperature distribution inside the reactor core of pebble bed type high temperature reactors, in this thesis we investigated the stochastic properties of randomly stacked beds and the effects of the non-homogeneity of these beds on the neutronics and thermal-hydraulic

  15. HTGR severe accident sequence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, R.M.; Ball, S.J.; Kornegay, F.C.

    1982-01-01

    Thermal-hydraulic, fission product transport, and atmospheric dispersion calculations are presented for hypothetical severe accident release paths at the Fort St. Vrain (FSV) high temperature gas cooled reactor (HTGR). Off-site radiation exposures are calculated for assumed release of 100% of the 24 hour post-shutdown core xenon and krypton inventory and 5.5% of the iodine inventory. The results show conditions under which dose avoidance measures would be desirable and demonstrate the importance of specific release characteristics such as effective release height. 7 tables.

  16. HTGR Fuel Technology Program. Semiannual report for the period ending March 31, 1983

    Energy Technology Data Exchange (ETDEWEB)

    1983-07-01

    This document reports the technical accomplishments of the HTGR Fuel Technology Program at GA Technologies Inc. during the first half of FY 83. The activities include the fuel process, fuel materials, fuel cycle, fission product transport, core component verification, and core technology transfer tasks necessary to support the design and development of a steam cycle/cogeneration (SC/C) version of the HTGR.

  17. HTGR fuel element structural design considerations

    Energy Technology Data Exchange (ETDEWEB)

    Alloway, R.; Gorholt, W.; Ho, F.; Vollman, R.; Yu, H.

    1986-09-01

    The structural design of the large HTGR prismatic core fuel elements involve the interaction of four engineering disciplines: nuclear physics, thermo-hydraulics, structural and material science. Fuel element stress analysis techniques and the development of structural criteria are discussed in the context of an overview of the entire design process. The core of the proposed 2240 MW(t) HTGR is described as an example where the design process was used. Probabalistic stress analysis techniques coupled with probabalistic risk analysis (PRA) to develop structural criteria to account for uncertainty are described. The PRA provides a means for ensuring that the proposed structural criteria are consistent with plant investment and safety risk goals. The evaluation of cracked fuel elements removed from the Fort St. Vrain reactor in the USA is discussed in the context of stress analysis uncertainty and structural criteria development.

  18. HTGR gas turbine program. Semiannual progress report, April 1-September 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1979-12-01

    This report describes work performed under the gas turbine HTGR (HTGR-GT) program, Department of Energy Contract DE-AT03-76-SF70046, during the period April 1, 1978 through September 30, 1978. The work reported covers the demonstration and commercial plant concept studies including plant layout, heat exchanger studies, turbomachine studies, systems analysis, and reactor core engineering.

  19. In-core fuel management for pebble-bed reactors

    Energy Technology Data Exchange (ETDEWEB)

    Milian Perez, Daniel; Rodriguez Garcia, Lorena; Garcia Hernandez, Carlos; Milian Lorenzo, Daniel, E-mail: dperez@instec.cu, E-mail: cgh@instec.cu, E-mail: dmilian@instec.cu [Higher Institute of Technologies and Applied Sciences, Havana (Cuba); Velasco, Abanades, E-mail: abanades@etsii.upm.es [Department of Simulation of Thermo Energy Systems, Polytechnic University of Madrid (Spain)

    2013-07-01

    In this paper a calculation procedure to reduce the power peak in the core of a Very High Temperature pebble bed Reactor is presented. This procedure combines the fuel depletion and the neutronic behavior of the fuel in the reactor core, modeling once-through-then-out cycles as well as cycles in which pebbles are recirculated through the core an arbitrary number of times, obtaining the asymptotic fuel-loading pattern. The procedure consists in several coupled computational codes, which are used iteratively until convergence is reached. The utilization of the MCNPX 2.6e, as one of these computational codes, is validated through the calculation of benchmarks announced by IAEA (IAEA-TECDOC-1249, 2001). To complete the verification of the calculation procedure a base case described in (Annals of Nuclear Energy 29 (2002) 1345-1364), was performed. The procedure has been applied to a model of Pebble Bed Modular Reactor (200 MW) design. (author)

  20. Core Optimization of a Deep-Burn Pebble Bed Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Brian Boer; Abderrafi M. Ougouag

    2010-06-01

    Achieving a high fuel burnup in the Deep-Burn (DB) pebble bed reactor design, while remaining within the limits for fuel temperature, power peaking and temperature reactivity feedback, is challenging. The high content of Pu and Minor Actinides in the Deep-Burn fuel significantly impacts the thermal neutron energy spectrum as compared to a ’standard’ UO2 fueled core. This can result in power and temperature peaking in the pebble bed core in locally thermalized regions near the graphite reflectors. Furthermore, the interplay of the Pu resonances of the neutron absorption cross sections at low-lying energies can lead to a positive temperature reactivity coefficient for the graphite moderator at certain operating conditions. The DB concept focuses on the destruction of spent fuel transuranics in TRISO coated particle fueled gas-cooled reactors with the aim of a fractional fuel burnup of 60-70% in fissions per initial metal atom (FIMA), using a single-pass, multi in-core fuel (re)cycling scheme. In principle, the DB pebble bed concept employs the same reactor designs as the present low enriched uranium core designs, i.e. the 400 MWth Pebble Bed Modular Reactor (PBMR-400). A Pu and Minor Actinide fueled PBMR-400 design serves as the starting point for a core optimization study. The fuel temperature, power peak, temperature reactivity coefficients, and burnup capabilities of the modified designs are analyzed with the PEBBED code. A code-to-code coupling with the PASTA code allows for the analysis of the TRISO fuel performance for both normal and Loss Of Forced Cooling conditions. An improved core design is sought, maximizing the fuel discharge burnup, while retaining negative temperature reactivity feedback coefficients for the entire temperature range and avoiding high fuel temperatures (fuel failure probabilities).

  1. Study on commercial HTGR hydrogen production system

    Energy Technology Data Exchange (ETDEWEB)

    Nishihara, Tetsuo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Hada, Kazuhiko [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Nishimura, Kuniyuki [Mitsubishi Research Institute, Tokyo (Japan)

    2000-07-01

    The Japanese energy demand in 2030 will increase up to 117% in comparison with one in 2000. We have to avoid a large consumption of fossil fuel that induces a large CO{sub 2} emission from viewpoint of global warming. Furthermore new energy resources expected to resolve global warming have difficulty to be introduced more because of their low energy density. As a result, nuclear power still has a possibility of large introduction to meet the increasing energy demand. On the other hand, in Japan, 40% of fossil fuels in the primary energy are utilized for power generation, and the remaining are utilized as a heat source. New clean energy is required to reduce the consumption of fossil fuels and hydrogen is expected as a alternative energy resource. Prediction of potential hydrogen demand in Japan is carried out and it is clarified that the demand will potentially increase up to 4% of total primary energy in 2050. In present, steam reforming method is the most economical among hydrogen generation processes and the cost of hydrogen production is about 7 to 8 yen/m{sup 3} in Europe and the United States and about 13 yen/m{sup 3} in Japan. JAERI has proposed for using the HTGR whose maximum core outlet temperature is at 950degC as a heat source in the steam reforming to reduced the consumption of fossil fuels and resulting CO{sub 2} emission. Based on the survey of the production rate and the required thermal energy in conventional industry, it is clarified that a hydrogen production system by the steam reforming is the best process for the commercial HTGR nuclear heat utilization. The HTGR steam reforming system and other candidate nuclear heat utilization systems are considered from viewpoint of system layout and economy. From the results, the hydrogen production cost in the HTGR stream reforming system is expected to be about 13.5 yen/m{sup 3} if the cost of nuclear heat of the HTGR is the same as one of the LWR. (author)

  2. HTGR-GT and electrical load integrated control

    Energy Technology Data Exchange (ETDEWEB)

    Chan, T.; Openshaw, F.; Pfremmer, D.

    1980-05-01

    A discussion of the control and operation of the HTGR-GT power plant is presented in terms of its closely coupled electrical load and core cooling functions. The system and its controls are briefly described and comparisons are made with more conventional plants. The results of analyses of selected transients are presented to illustrate the operation and control of the HTGR-GT. The events presented were specifically chosen to show the controllability of the plant and to highlight some of the unique characteristics inherent in this multiloop closed-cycle plant.

  3. HTGR spent fuel composition and fuel element block flow

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, C.J.; Holder, N.D.; Pierce, V.H.; Robertson, M.W.

    1976-07-01

    The High-Temperature Gas-Cooled Reactor (HTGR) utilizes the thorium-uranium fuel cycle. Fully enriched uranium fissile material and thorium fertile material are used in the initial reactor core and for makeup fuel in the recycle core loadings. Bred /sup 233/U and unburned /sup 235/U fissile materials are recovered from spent fuel elements, refabricated into recycle fuel elements, and used as part of the recycle core loading along with the makeup fuel elements. A typical HTGR employs a 4-yr fuel cycle with approximately one-fourth of the core discharged and reloaded annually. The fuel element composition, including heavy metals, impurity nuclides, fission products, and activation products, has been calculated for discharged spent fuel elements and for reload fresh fuel and recycle fuel elements for each cycle over the life of a typical HTGR. Fuel element compositions are presented for the conditions of equilibrium recycle. Data describing compositions for individual reloads throughout the reactor life are available in a detailed volume upon request. Fuel element block flow data have been compiled based on a forecast HTGR market. Annual block flows are presented for each type of fuel element discharged from the reactors for reprocessing and for refabrication.

  4. The Transient 3-D Transport Coupled Code TORT-TD/ATTICA3D for High-Fidelity Pebble-Bed HTGR Analyses

    Science.gov (United States)

    Seubert, Armin; Sureda, Antonio; Lapins, Janis; Bader, Johannes; Laurien, Eckart

    2012-01-01

    This article describes the 3D discrete ordinates-based coupled code system TORT-TD/ATTICA3D that aims at steady state and transient analyses of pebble-bed high-temperature gas cooled reactors. In view of increasing computing power, the application of time-dependent neutron transport methods becomes feasible for best estimate evaluations of safety margins. The calculation capabilities of TORT-TD/ATTICA3D are presented along with the coupling approach, with focus on the time-dependent neutron transport features of TORT-TD. Results obtained for the OECD/NEA/NSC PBMR-400 benchmark demonstrate the transient capabilities of TORT-TD/ATTICA3D.

  5. HTGR fuel and fuel cycle technology

    Energy Technology Data Exchange (ETDEWEB)

    Lotts, A.L.; Coobs, J.H.

    1976-08-01

    The status of fuel and fuel cycle technology for high-temperature gas-cooled reactors (HTGRs) is reviewed. The all-ceramic core of the HTGRs permits high temperatures compared with other reactors. Core outlet temperatures of 740/sup 0/C are now available for the steam cycle. For advanced HTGRs such as are required for direct-cycle power generation and for high-temperature process heat, coolant temperatures as high as 1000/sup 0/C may be expected. The paper discusses the variations of HTGR fuel designs that meet the performance requirements and the requirements of the isotopes to be used in the fuel cycle. Also discussed are the fuel cycle possibilities, which include the low-enrichment cycle, the Th-/sup 233/U cycle, and plutonium utilization in either cycle. The status of fuel and fuel cycle development is summarized.

  6. HTGR fuels and core development program. Quarterly progress report for the period ending November 30, 1976. [Graphite and fuel irradiations; fission product release

    Energy Technology Data Exchange (ETDEWEB)

    1976-12-27

    The work reported includes studies of reactions between core materials and coolant impurities, basic fission product transport mechanisms, core graphite development and testing, the development and testing of recyclable fuel systems, and physics and fuel management studies. Materials studies include irradiation capsule tests of both fuel and graphite. Experimental procedures and results are discussed and the data are presented in tables, graphs, and photographs.

  7. HTGR Fuels and Core Development Program. Quarterly progress report for the period ending August 31, 1977. [Graphite and fuel irradiation; fission product release

    Energy Technology Data Exchange (ETDEWEB)

    1977-09-01

    The work reported includes studies of reactions between core materials and coolant impurities, basic fission product transport mechanisms, core graphite development and testing, the development and testing of recyclable fuel systems, and physics and fuel management studies. Materials studies include irradiation capsule tests of both fuel and graphite. Experimental procedures and results are discussed and data are presented.

  8. Water column and bed-sediment core samples collected from Brownlee Reservoir near Oxbow, Oregon, 2012

    Science.gov (United States)

    Fosness, Ryan L.; Naymik, Jesse; Hopkins, Candice B.; DeWild, John F.

    2013-01-01

    The U.S. Geological Survey, in cooperation with Idaho Power Company, collected water-column and bed-sediment core samples from eight sites in Brownlee Reservoir near Oxbow, Oregon, during May 5–7, 2012. Water-column and bed-sediment core samples were collected at each of the eight sites and analyzed for total mercury and methylmercury. Additional bed-sediment core samples, collected from three of the eight sites, were analyzed for pesticides and other organic compounds, trace metals, and physical characteristics, such as particle size. Total mercury and methylmercury were detected in each of the water column and bed-sediment core samples. Only 17 of the 417 unique pesticide and organic compounds were detected in bed-sediment core samples. Concentrations of most organic wastewater compounds detected in bed sediment were less than the reporting level. Trace metals detected were greater than the reporting level in all the bed-sediment core samples submitted for analysis. The particle size distribution of bed-sediment core samples was predominantly clay mixed with silt.

  9. HTGR nuclear heat source component design and experience

    Energy Technology Data Exchange (ETDEWEB)

    Peinado, C.O.; Wunderlich, R.G.; Simon, W.A.

    1982-05-01

    The high-temperature gas-cooled reactor (HTGR) nuclear heat source components have been under design and development since the mid-1950's. Two power plants have been designed, constructed, and operated: the Peach Bottom Atomic Power Station and the Fort St. Vrain Nuclear Generating Station. Recently, development has focused on the primary system components for a 2240-MW(t) steam cycle HTGR capable of generating about 900 MW(e) electric power or alternately producing high-grade steam and cogenerating electric power. These components include the steam generators, core auxiliary heat exchangers, primary and auxiliary circulators, reactor internals, and thermal barrier system. A discussion of the design and operating experience of these components is included.

  10. HTGR fuels and core development program. Quarterly progress report for the period ending November 30, 1977. [Graphite and fuel irradiation; fission product release

    Energy Technology Data Exchange (ETDEWEB)

    1977-12-01

    The work reported here includes studies of basic fission product transport mechanisms, core graphite development and testing, and the development and testing of recyclable fuel systems. Materials studied include irradiation capsule tests of both fuel and graphite. Experimental procedures and results are discussed and data are presented.

  11. HTGR Cost Model Users' Manual

    Energy Technology Data Exchange (ETDEWEB)

    A.M. Gandrik

    2012-01-01

    The High Temperature Gas-Cooler Reactor (HTGR) Cost Model was developed at the Idaho National Laboratory for the Next Generation Nuclear Plant Project. The HTGR Cost Model calculates an estimate of the capital costs, annual operating and maintenance costs, and decommissioning costs for a high-temperature gas-cooled reactor. The user can generate these costs for multiple reactor outlet temperatures; with and without power cycles, including either a Brayton or Rankine cycle; for the demonstration plant, first of a kind, or nth of a kind project phases; for a single or four-pack configuration; and for a reactor size of 350 or 600 MWt. This users manual contains the mathematical models and operating instructions for the HTGR Cost Model. Instructions, screenshots, and examples are provided to guide the user through the HTGR Cost Model. This model was design for users who are familiar with the HTGR design and Excel. Modification of the HTGR Cost Model should only be performed by users familiar with Excel and Visual Basic.

  12. Thermal-hydraulic analysis techniques for axisymmetric pebble bed nuclear reactor cores. [PEBBLE code

    Energy Technology Data Exchange (ETDEWEB)

    Stroh, K.R.

    1979-03-01

    The pebble bed reactor's cylindrical core volume contains a random bed of small, spherical fuel-moderator elements. These graphite spheres, containing a central region of dispersed coated-particle fissile and fertile material, are cooled by high pressure helium flowing through the connected interstitial voids. A mathematical model and numerical solution technique have been developed which allow calculation of macroscopic values of thermal-hydraulic variables in an axisymmetric pebble bed nuclear reactor core. The computer program PEBBLE is based on a mathematical model which treats the bed macroscopically as a generating, conducting porous medium. The steady-state model uses a nonlinear Forchheimer-type relation between the coolant pressure gradient and mass flux, with newly derived coefficients for the linear and quadratic resistance terms. The remaining equations in the model make use of mass continuity, and thermal energy balances for the solid and fluid phases.

  13. Optimized core design and fuel management of a pebble-bed type nuclear reactor

    NARCIS (Netherlands)

    Boer, B.

    2009-01-01

    The core design of a pebble-bed type Very High Temperature Reactor (VHTR) is optimized, aiming for an increase of the coolant outlet temperature to 1000 C, while retaining its inherent safety features. The VHTR has been selected by the international Generation IV research initiative as one of the si

  14. Creation of a Test Bed Environment for Core Java Applications using White Box Testing Approaches

    Directory of Open Access Journals (Sweden)

    Priya R. L

    2012-10-01

    Full Text Available A Test Bed Environment allows for rigorous, transparent, and replicable testing of scientific theories. However, in software development these test beds can be specified hardware and software environment for the application under test. Though the existing open source test bed environments in Integrated Development Environment (IDEs are capable of supporting the development of Java application types, test reports are generated by third party developers. They do not enhance the utility and the performance of the system constructed. Our proposed system, we have created a customized test bed environment for core java application programs used to generate the test case report using generated control flow graph. This can be obtained by developing a new mini compiler with additional features.

  15. Modular HTGR Safety Basis and Approach

    Energy Technology Data Exchange (ETDEWEB)

    Thomas Hicks

    2011-08-01

    The Next Generation Nuclear Plant (NGNP) will be a licensed commercial high temperature gas-cooled reactor (HTGR) capable of producing electricity and/or high temperature process heat for industrial markets supporting a range of end-user applications. The NGNP Project has adopted the 10 CFR 52 Combined License (COL) process, as recommended in the NGNP Licensing Strategy - A Report to Congress, dated August 2008, as the foundation for the NGNP licensing strategy [DOE/NRC 2008]. Nuclear Regulatory Commission (NRC) licensing of the NGNP plant utilizing this process will demonstrate the efficacy for licensing future HTGRs for commercial industrial applications. This information paper is one in a series of submittals that address key generic issues of the priority licensing topics as part of the process for establishing HTGR regulatory requirements. This information paper provides a summary level introduction to HTGR history, public safety objectives, inherent and passive safety features, radionuclide release barriers, functional safety approach, and risk-informed safety approach. The information in this paper is intended to further the understanding of the modular HTGR safety approach with the NRC staff and public stakeholders. The NGNP project does not expect to receive comments on this information paper because other white papers are addressing key generic issues of the priority licensing topics in greater detail.

  16. Advanced Core Design And Fuel Management For Pebble-Bed Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hans D. Gougar; Abderrafi M. Ougouag; William K. Terry

    2004-10-01

    A method for designing and optimizing recirculating pebble-bed reactor cores is presented. At the heart of the method is a new reactor physics computer code, PEBBED, which accurately and efficiently computes the neutronic and material properties of the asymptotic (equilibrium) fuel cycle. This core state is shown to be unique for a given core geometry, power level, discharge burnup, and fuel circulation policy. Fuel circulation in the pebble-bed can be described in terms of a few well?defined parameters and expressed as a recirculation matrix. The implementation of a few heat?transfer relations suitable for high-temperature gas-cooled reactors allows for the rapid estimation of thermal properties critical for safe operation. Thus, modeling and design optimization of a given pebble-bed core can be performed quickly and efficiently via the manipulation of a limited number key parameters. Automation of the optimization process is achieved by manipulation of these parameters using a genetic algorithm. The end result is an economical, passively safe, proliferation-resistant nuclear power plant.

  17. CORE ANALYSIS, DESIGN AND OPTIMIZATION OF A DEEP-BURN PEBBLE BED REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    B. Boer; A. M. Ougouag

    2010-05-01

    Achieving a high burnup in the Deep-Burn pebble bed reactor design, while remaining within the limits for fuel temperature, power peaking and temperature reactivity feedback, is challenging. The high content of Pu and Minor Actinides in the Deep-Burn fuel significantly impacts the thermal neutron energy spectrum. This can result in power and temperature peaking in the pebble bed core in locally thermalized regions near the graphite reflectors. Furthermore, the interplay of the Pu resonances of the neutron absorption cross sections at low-lying energies can lead to a positive temperature reactivity coefficient for the graphite moderator at certain operating conditions. To investigate the aforementioned effects a code system using existing codes has been developed for neutronic, thermal-hydraulic and fuel depletion analysis of Deep-Burn pebble bed reactors. A core analysis of a Deep-Burn Pebble Bed Modular Reactor (400 MWth) design has been performed for two Deep-Burn fuel types and possible improvements of the design with regard to power peaking and temperature reactivity feedback are identified.

  18. Symbiotic Pu/Th fuel cycle for HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Girardi, Enrico; Lecarpentier, David [EDF R and D, Les Renardieres, 77818 Moret sur Loing cedex (France)

    2006-07-01

    HTGRs, loaded with uranium or plutonium fuel do not authorize high breeding ratios. Consequently, the Gen IV requirement of sustainability with respect to the use of fissile resources may be difficult to meet. Relying on the thorium conversion into fissile uranium 233, the use of thorium is promising regarding the breeding ratio. Accordingly, the symbiotic Pu/Th fuel cycle is an interesting way to optimize the energetic use of plutonium. In the first part of this paper, we compare the performances of HTRs with different types of fuel (15% enriched U, Pu alone, Th-Pu) on the resource consumption. Relying on HTGRs, a good conversion ratio (typically 0.8) is mandatory to satisfy high temperature needs in the long term. In the second part, we discuss the neutronic calculation scheme for a prismatic HTGR annular core (GTMHR like, with an internal graphite reflector), and for a large HTGR (modeled with an assembly calculation). In the last part of the paper, Pu/Th, U233/Th and Pu-U233/Th fuel cycle are studied for the two types of HTGRs. The performances in terms of conversion ratios are compared. For a given power of 300 Mwe, several compositions for the fuel are studied. The fraction of thorium in the fuel composition is varying from 0% to 99% and the total fuel mass charged in the core ranges from 1200 kg to 15,000 kg. We show that good conversion ratios are very difficult to obtain for annular HTGRs. New designs must be considered, with a larger core, and a smaller power density (to reach the passive evacuation of residual power). Finally, a preliminary strategy for the deployment of these fuel cycles is presented. (authors)

  19. HTGR generic technology program. Semiannual report ending March 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-05-01

    This document reports the technical accomplishments on the HTGR Generic Technology Program at General Atomic during the first half of FY-80. It covers a period when the design direction of the National HTGR Program is in the process of an overall review. The HTGR Generic Technology Program activities have continued so as to provide the basic technology required for all HTGR applications. The activities include the need to develop an MEU fuel and the need to qualify materials and components for the higher temperatures of the gas turbine and process heat plants.

  20. Fission-product retention in HTGR fuels

    Energy Technology Data Exchange (ETDEWEB)

    Homan, F.J.; Kania, M.J.; Tiegs, T.N.

    1982-01-01

    Retention data for gaseous and metallic fission products are presented for both Triso-coated and Biso-coated HTGR fuel particles. Performance trends are established that relate fission product retention to operating parameters, such as temperature, burnup, and neutron exposure. It is concluded that Biso-coated particles are not adequately retentive of fission gas or metallic cesium, and Triso-coated particles which retain cesium still lose silver. Design implications related to these performance trends are identified and discussed.

  1. HTGR Mechanistic Source Terms White Paper

    Energy Technology Data Exchange (ETDEWEB)

    Wayne Moe

    2010-07-01

    The primary purposes of this white paper are: (1) to describe the proposed approach for developing event specific mechanistic source terms for HTGR design and licensing, (2) to describe the technology development programs required to validate the design methods used to predict these mechanistic source terms and (3) to obtain agreement from the NRC that, subject to appropriate validation through the technology development program, the approach for developing event specific mechanistic source terms is acceptable

  2. New small HTGR power plant concept with inherently safe features - an engineering and economic challenge

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, C.F.; Sonn, D.L.

    1983-01-01

    Studies are in a very early design stage to establish a modular concept High-Temperature Gas-Cooled Reactor (HTGR) plant of about 100-MW(e) size to meet the special needs of small energy users in the industrialized and developing nations. The basic approach is to design a small system in which, even under the extreme conditions of loss of reactor pressure and loss of forced core cooling, the temperature would remain low enough so that the fuel would retain essentially all the fission products and the owner's investment would not be jeopardized. To realize economic goals, the designer faces the challenge of providing a standardized nuclear heat source, relying on a high percentage of factory fabrication to reduce site construction time, and keeping the system simple. While the proposed nuclear plant concept embodies new features, there is a large technology base to draw upon for the design of a small HTGR.

  3. 高温气冷堆和轻水堆超铀元素管理特性研究%Management Feature of Transuranic for HTGR and LWR

    Institute of Scientific and Technical Information of China (English)

    位金锋; 李富; 孙玉良

    2013-01-01

    Long-lived actinides from spent fuels can cause potential long-term environmental hazards.The generation and incineration of transuranic in different closed fuel cycles were studied.U and Pu were recycled from spent fuel in the 250 MW hightemperature gas-cooled reactor-pebble-bed-module (HTR-PM) U-Pu fuelled core,and then PuO2 and MOX fuel elements were designed based on this recycled U and Pu.These fuel elements were used to build up a new PuO2 or MOX fuelled core with the same geometry of the original reactor.Characteristics of transuranic incineration with HTGR open and closed fuel cycles were studied with VSOP code,and the corresponding results from the light water reactor were compared and analyzed.The transuranic generation with HTGR open fuel cycle is almost half of the corresponding result of the light water reactor.Thus,HTGR closed fuel cycles can effectively burn transuranic.%乏燃料中长寿命锕系元素对环境造成长期潜在危害,本文研究球床高温气冷堆不同燃料循环中超铀元素的产生和焚烧特性.在250 MW球床模块式高温气冷堆示范电站HTR-PM铀钚循环的乏燃料中提取铀和钚作为核燃料,设计了PuO2和MOX燃料元件,将新设计的燃料元件重新装入与HTR-PM相同结构和尺寸的堆芯,分别形成纯钚燃料循环和MOX燃料循环.采用高温气冷堆物理设计程序VSOP,研究了高温气冷堆一次通过燃料循环和不同闭式燃料循环的超铀元素焚烧特性,并与轻水堆燃料循环结果进行比较和分析.结果表明:高温气冷堆一次通过燃料循环超铀元素生成率约为轻水堆的1/2;高温气冷堆闭式燃料循环能有效嬗变超铀元素.

  4. Coring to the West Antarctic ice sheet bed with a new Deep Ice Sheet Coring (DISC) drill

    Science.gov (United States)

    Bentley, C. R.; Taylor, K. C.; Shturmakov, A. J.; Mason, W. P.; Emmel, G. R.; Lebar, D. A.

    2005-05-01

    As a contribution to IPY 2007-2008, the U.S. ice core research community, supported by the National Science Foundation, plans to core through the West Antarctic ice sheet (WAIS) at the ice-flow divide between the Ross Sea and Amundsen Sea drainage systems. The aim is to develop a unique series of interrelated climatic, ice-dynamic, and biologic records focused on understanding interactions among global earth systems. There will be approximately 15 separate but synergistic projects to analyze the ice and interpret the records. The most significant expected outcome of the WAIS Divide program will be climate records for the last ~40,000 years with an annually resolved chronology (through layer counting), comparable to the records from central Greenland. The data will also extend, at lower temporal resolution, to approximately 100,000 BP. These records will permit comparison of environmental conditions between the northern and southern hemispheres, and study of greenhouse gas concentrations in the paleoatmosphere, with unprecedented detail. To accomplish the coring, an innovative new Deep Ice Sheet Coring (DISC) drill is being built at the University of Wisconsin. The modular design of the bore-hole assembly (sonde) provides high flexibility for producing a 122 mm diameter ice core to depths of 4,000 m with maximum core lengths of 4 m. The DISC drill has a rotating outer barrel that can be used with or without an inner barrel designed to improve core recovery in brittle ice. Separate and independent motors for the drill and pump allow cutter speeds from 0 to 150 rpm and pump rates from 0 to 140 gpm. The high pumping rate should alleviate problems drilling in warm ice near the bed; it also helps make tripping speeds several times faster than with the old US drill. Other innovations include vibration and acoustic sensors for monitoring the drilling process, a segmented core barrel to avoid the formerly persistent problem of bent core barrels, and a high-speed data

  5. HTGR Application Economic Model Users' Manual

    Energy Technology Data Exchange (ETDEWEB)

    A.M. Gandrik

    2012-01-01

    The High Temperature Gas-Cooled Reactor (HTGR) Application Economic Model was developed at the Idaho National Laboratory for the Next Generation Nuclear Plant Project. The HTGR Application Economic Model calculates either the required selling price of power and/or heat for a given internal rate of return (IRR) or the IRR for power and/or heat being sold at the market price. The user can generate these economic results for a range of reactor outlet temperatures; with and without power cycles, including either a Brayton or Rankine cycle; for the demonstration plant, first of a kind, or nth of a kind project phases; for up to 16 reactor modules; and for module ratings of 200, 350, or 600 MWt. This users manual contains the mathematical models and operating instructions for the HTGR Application Economic Model. Instructions, screenshots, and examples are provided to guide the user through the HTGR Application Economic Model. This model was designed for users who are familiar with the HTGR design and Excel and engineering economics. Modification of the HTGR Application Economic Model should only be performed by users familiar with the HTGR and its applications, Excel, and Visual Basic.

  6. Results for Phase I of the IAEA Coordinated Research Program on HTGR Uncertainties

    Energy Technology Data Exchange (ETDEWEB)

    Strydom, Gerhard [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bostelmann, Friederike [Idaho National Lab. (INL), Idaho Falls, ID (United States); Yoon, Su Jong [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-01-01

    The quantification of uncertainties in design and safety analysis of reactors is today not only broadly accepted, but in many cases became the preferred way to replace traditional conservative analysis for safety and licensing analysis. The use of a more fundamental methodology is also consistent with the reliable high fidelity physics models and robust, efficient, and accurate codes available today. To facilitate uncertainty analysis applications a comprehensive approach and methodology must be developed and applied. High Temperature Gas-cooled Reactors (HTGR) has its own peculiarities, coated particle design, large graphite quantities, different materials and high temperatures that also require other simulation requirements. The IAEA has therefore launched a Coordinated Research Project (CRP) on the HTGR Uncertainty Analysis in Modeling (UAM) in 2013 to study uncertainty propagation specifically in the HTGR analysis chain. Two benchmark problems are defined, with the prismatic design represented by the General Atomics (GA) MHTGR-350 and a 250 MW modular pebble bed design similar to the HTR-PM (INET, China). This report summarizes the contributions of the HTGR Methods Simulation group at Idaho National Laboratory (INL) up to this point of the CRP. The activities at INL have been focused so far on creating the problem specifications for the prismatic design, as well as providing reference solutions for the exercises defined for Phase I. An overview is provided of the HTGR UAM objectives and scope, and the detailed specifications for Exercises I-1, I-2, I-3 and I-4 are also included here for completeness. The main focus of the report is the compilation and discussion of reference results for Phase I (i.e. for input parameters at their nominal or best-estimate values), which is defined as the first step of the uncertainty quantification process. These reference results can be used by other CRP participants for comparison with other codes or their own reference

  7. Computational Model for the Neutronic Simulation of Pebble Bed Reactor’s Core Using MCNPX

    Directory of Open Access Journals (Sweden)

    J. Rosales

    2014-01-01

    Full Text Available Very high temperature reactor (VHTR designs offer promising performance characteristics; they can provide sustainable energy, improved proliferation resistance, inherent safety, and high temperature heat supply. These designs also promise operation to high burnup and large margins to fuel failure with excellent fission product retention via the TRISO fuel design. The pebble bed reactor (PBR is a design of gas cooled high temperature reactor, candidate for Generation IV of Nuclear Energy Systems. This paper describes the features of a detailed geometric computational model for PBR whole core analysis using the MCNPX code. The validation of the model was carried out using the HTR-10 benchmark. Results were compared with experimental data and calculations of other authors. In addition, sensitivity analysis of several parameters that could have influenced the results and the accuracy of model was made.

  8. A simulation of a pebble bed reactor core by the MCNP-4C computer code

    Directory of Open Access Journals (Sweden)

    Bakhshayesh Moshkbar Khalil

    2009-01-01

    Full Text Available Lack of energy is a major crisis of our century; the irregular increase of fossil fuel costs has forced us to search for novel, cheaper, and safer sources of energy. Pebble bed reactors - an advanced new generation of reactors with specific advantages in safety and cost - might turn out to be the desired candidate for the role. The calculation of the critical height of a pebble bed reactor at room temperature, while using the MCNP-4C computer code, is the main goal of this paper. In order to reduce the MCNP computing time compared to the previously proposed schemes, we have devised a new simulation scheme. Different arrangements of kernels in fuel pebble simulations were investigated and the best arrangement to decrease the MCNP execution time (while keeping the accuracy of the results, chosen. The neutron flux distribution and control rods worth, as well as their shadowing effects, have also been considered in this paper. All calculations done for the HTR-10 reactor core are in good agreement with experimental results.

  9. HTGR Economic / Business Analysis and Trade Studies Market Analysis for HTGR Technologies and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Richards, Matt [Ultra Safe Nuclear Corporation, Los Alamos, NM (United States); Hamilton, Chris [Ultra Safe Nuclear Corporation, Los Alamos, NM (United States)

    2013-11-01

    This report provides supplemental information to the assessment of target markets provided in Appendix A of the 2012 Next Generation Nuclear Plant (NGNP) Industry Alliance (NIA) business plan [NIA 2012] for deployment of High Temperature Gas-Cooled Reactors (HTGRs) in the 2025 – 2050 time frame. This report largely reiterates the [NIA 2012] assessment for potential deployment of 400 to 800 HTGR modules (100 to 200 HTGR plants with 4 reactor modules) in the 600-MWt class in North America by 2050 for electricity generation, co-generation of steam and electricity, oil sands operations, hydrogen production, and synthetic fuels production (e.g., coal to liquids). As the result of increased natural gas supply from hydraulic fracturing, the current and historically low prices of natural gas remain a significant barrier to deployment of HTGRs and other nuclear reactor concepts in the U.S. However, based on U.S. Department of Energy (DOE) Energy Information Agency (EIA) data, U.S. natural gas prices are expected to increase by the 2030 – 2040 timeframe when a significant number of HTGR modules could be deployed. An evaluation of more recent EIA 2013 data confirms the assumptions in [NIA 2012] of future natural gas prices in the range of approximately $7/MMBtu to $10/MMBtu during the 2030 – 2040 timeframe. Natural gas prices in this range will make HTGR energy prices competitive with natural gas, even in the absence of carbon-emissions penalties. Exhibit ES-1 presents the North American projections in each market segment including a characterization of the market penetration logic. Adjustments made to the 2012 data (and reflected in Exhibit ES-1) include normalization to the slightly larger 625MWt reactor module, segregation between steam cycle and more advanced (higher outlet temperature) modules, and characterization of U.S. synthetic fuel process applications as a separate market segment.

  10. Using SA508/533 for the HTGR Vessel Material

    Energy Technology Data Exchange (ETDEWEB)

    Larry Demick

    2012-06-01

    This paper examines the influence of High Temperature Gas-cooled Reactor (HTGR) module power rating and normal operating temperatures on the use of SA508/533 material for the HTGR vessel system with emphasis on the calculated times at elevated temperatures approaching or exceeding ASME Code Service Limits (Levels B&C) to which the reactor pressure vessel could be exposed during postulated pressurized and depressurized conduction cooldown events over its design lifetime.

  11. HTGR Generic Technology Program. Semiannual report for the period ending March 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1979-06-01

    This document reports the technical accomplishments on the HTGR Generic Technology Program at General Atomic during the first half of FY-79. It covers a period when the major design direction of the National HTGR Program is in the process of changing from the HTGR-SC emphasis to an HTGR-GT emphasis in the near term. The HTGR Generic Technology Program activities have been redirected to ensure that the tasks covered are supportive of this changing emphasis in HTGR applications. The activities include the need to develop a medium enriched uranium (MEU) fuel, and the need to qualify materials and components for the higher temperatures of the gas turbine plant.

  12. HTGR Generic Technology Program. Semiannual report for the period ending September 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1979-11-01

    The technical accomplishments on the HTGR Generic Technology Program at General Atomic during the second half of FY-79 are reported. The report covers a period when the major design direction of the National HTGR Program is in the process of changing from the HTGR-SC emphasis to an HTGR-GT emphasis in the near term. The HTGR Generic Technology Program activities have been redirected to ensure that the tasks covered are supportive of this changing emphasis in HTGR applications. The activities include the need to develop an MEU fuel, and the need to qualify materials and components for the higher temperatures of the gas turbine plant.

  13. Two Step Procedure Using a 1-D Slab Spectral Geometry in a Pebble Bed Reactor Core Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Chul; Kim, Kang Seog; Noh, Jae Man; Joo, Hyung Kook [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2005-07-01

    A strong spectral interaction between the core and the reflector has been one of the main concerns in the analysis of pebble bed reactor cores. To resolve this problem, VSOP adopted iteration between the spectrum calculation in a spectral zone and the global core calculation. In VSOP, the whole problem domain is divided into many spectral zones in which the fine group spectrum is calculated using bucklings for fast groups and albedos for thermal groups from the global core calculation. The resulting spectrum in each spectral zone is used to generate broad group cross sections of the spectral zone for the global core calculation. In this paper, we demonstrate a two step procedure in a pebble bed reactor core analysis. In the first step, we generate equivalent cross sections from a 1-D slab spectral geometry model with the help of the equivalence theory. The equivalent cross sections generated in this way include the effect of the spectral interaction between the core and the reflector. In the second step, we perform a diffusion calculation using the equivalent cross sections generated in the first step. A simple benchmark problem derived from the PMBR-400 Reactor was introduced to verify this approach. We compared the two step solutions with the Monte Carlo (MC) solutions for the problem.

  14. The IAEA Coordinated Research Program on HTGR Uncertainty Analysis: Phase I Status and Initial Results

    Energy Technology Data Exchange (ETDEWEB)

    Strydom, Gerhard; Bostelmann, Friederike; Ivanov, Kostadin

    2014-10-01

    required confidence level. In order to address uncertainty propagation in analysis and methods in the HTGR community the IAEA initiated a Coordinated Research Project (CRP) on the HTGR Uncertainty Analysis in Modelling (UAM) that officially started in 2013. Although this project focuses specifically on the peculiarities of HTGR designs and its simulation requirements, many lessons can be learned from the LWR community and the significant progress already made towards a consistent methodology uncertainty analysis. In the case of LWRs the NRC has already in 1988 amended 10 CFR 50.46 to allow best-estimate (plus uncertainties) calculations of emergency core cooling system performance. The Nuclear Energy Agency (NEA) of the Organization for Economic Co-operation and Development (OECD) also established an Expert Group on "Uncertainty Analysis in Modelling" which finally led to the definition of the "Benchmark for Uncertainty Analysis in Modelling (UAM) for Design, Operation and Safety Analysis of LWRs". The CRP on HTGR UAM will follow as far as possible the on-going OECD Light Water Reactor UAM benchmark activity.

  15. Very High Temperature Reactor (VHTR) Deep Burn Core and Fuel Analysis -- Complete Design Selection for the Pebble Bed Reactor

    Energy Technology Data Exchange (ETDEWEB)

    B. Boer; A. M. Ougouag

    2010-09-01

    The Deep-Burn (DB) concept focuses on the destruction of transuranic nuclides from used light water reactor fuel. These transuranic nuclides are incorporated into TRISO coated fuel particles and used in gas-cooled reactors with the aim of a fractional fuel burnup of 60 to 70% in fissions per initial metal atom (FIMA). This high performance is expected through the use of multiple recirculation passes of the fuel in pebble form without any physical or chemical changes between passes. In particular, the concept does not call for reprocessing of the fuel between passes. In principle, the DB pebble bed concept employs the same reactor designs as the presently envisioned low-enriched uranium core designs, such as the 400 MWth Pebble Bed Modular Reactor (PBMR-400). Although it has been shown in the previous Fiscal Year (2009) that a PuO2 fueled pebble bed reactor concept is viable, achieving a high fuel burnup, while remaining within safety-imposed prescribed operational limits for fuel temperature, power peaking and temperature reactivity feedback coefficients for the entire temperature range, is challenging. The presence of the isotopes 239-Pu, 240-Pu and 241-Pu that have resonances in the thermal energy range significantly modifies the neutron thermal energy spectrum as compared to a ”standard,” UO2-fueled core. Therefore, the DB pebble bed core exhibits a relatively hard neutron energy spectrum. However, regions within the pebble bed that are near the graphite reflectors experience a locally softer spectrum. This can lead to power and temperature peaking in these regions. Furthermore, a shift of the thermal energy spectrum with increasing temperature can lead to increased absorption in the resonances of the fissile Pu isotopes. This can lead to a positive temperature reactivity coefficient for the graphite moderator under certain operating conditions. The effort of this task in FY 2010 has focused on the optimization of the core to maximize the pebble discharge

  16. Fixed-bed adsorption separation of xylene isomers over sio2/silicallite-1 core-shell adsorbents

    KAUST Repository

    Khan, Easir A.

    2013-12-29

    SiO2/Silicalite-1 core-shell material has been demonstrated as potential shape selective adsorbent in gas phase separation of p-xylene from a mixture of p/o-xylene isomers. The core-shell composite comprised of large silica core and thin polycrystalline silicalite-1 shell which was synthesized via a self-assembly of silicalite-1 nanocrystals on core silica surface followed by a secondary seeded growth method. The core materials, SiO2 used in this study has mesoporosity with an average pore diameter of 60Å and hence offers no shape selectivity for xylene isomers. However, the shell, silicalite-1 contains rigid pore structures and preferentially adsorbs p-xylene from their isomers mixtures. A series of adsorption fixed bed breakthrough adsorption/desorption experiment was performed to obtain the equilibrium isotherms and adsorption isotherm parameters of xylene isomers. The equilibrium isotherms of xylene isomers follow the Langmuir\\'s model. A chromatographic adsorption model has been used to describe the fixed-bed breakthrough profiles of xylene isomers. The model has successfully predicted the responses of the binary mixtures of p/o-xylene isomers. The SiO2/silicalite-1 core-shell adsorbents have shown para-selectivity as high as 15. © Bangladesh Uni. of Engg. & Tech.

  17. The effects of applying silicon carbide coating on core reactivity of pebble-bed HTR in water ingress accident

    Energy Technology Data Exchange (ETDEWEB)

    Zuhair, S.; Setiadipura, Topan [National Nuclear Energy Agency of Indonesia, Serpong Tagerang Selatan (Indonesia). Center for Nuclear Reactor Technology and Safety; Su' ud, Zaki [Bandung Institute of Technology (Indonesia). Dept. of Physics

    2017-03-15

    Graphite is used as the moderator, fuel barrier material, and core structure in High Temperature Reactors (HTRs). However, despite its good thermal and mechanical properties below the radiation and high temperatures, it cannot avoid corrosion as a consequence of an accident of water/air ingress. Degradation of graphite as a main HTR material and the formation of dangerous CO gas is a serious problem in HTR safety. One of the several steps that can be adopted to avoid or prevent the corrosion of graphite by the water/air ingress is the application of a thin layer of silicon carbide (SiC) on the surface of the fuel element. This study investigates the effect of applying SiC coating on the fuel surfaces of pebble-bed HTR in water ingress accident from the reactivity points of view. A series of reactivity calculations were done with the Monte Carlo transport code MCNPX and continuous energy nuclear data library ENDF/B-VII at temperature of 1200 K. Three options of UO{sub 2}, PuO{sub 2}, and ThO{sub 2}/UO{sub 2} fuel kernel were considered to obtain the inter comparison of the core reactivity of pebble-bed HTR in conditions of water/air ingress accident. The calculation results indicated that the UO{sub 2}-fueled pebble-bed HTR reactivity was slightly reduced and relatively more decreased when the thickness of the SiC coating increased. The reactivity characteristic of ThO{sub 2}/UO{sub 2}-fueled pebble-bed HTR showed a similar trend to that of UO{sub 2}, but did not show reactivity peak caused by water ingress. In contrast with UO{sub 2}- and ThO{sub 2}-fueled pebble-bed HTR, although the reactivity of PuO{sub 2}-fueled pebble-bed HTR was the lowest, its characteristics showed a very high reactivity peak (0.33 Δk/k) and this introduction of positive reactivity is difficult to control. SiC coating on the surface of the plutonium fuel pebble has no significant impact. From the comparison between reactivity characteristics of uranium, thorium and plutonium cores with 0

  18. High-temperature Gas Reactor (HTGR)

    Science.gov (United States)

    Abedi, Sajad

    2011-05-01

    General Atomics (GA) has over 35 years experience in prismatic block High-temperature Gas Reactor (HTGR) technology design. During this period, the design has recently involved into a modular have been performed to demonstrate its versatility. This versatility is directly related to refractory TRISO coated - particle fuel that can contain any type of fuel. This paper summarized GA's fuel cycle studies individually and compares each based upon its cycle sustainability, proliferation-resistance capabilities, and other performance data against pressurized water reactor (PWR) fuel cycle data. Fuel cycle studies LEU-NV;commercial HEU-Th;commercial LEU-Th;weapons-grade plutonium consumption; and burning of LWR waste including plutonium and minor actinides in the MHR. results show that all commercial MHR options, with the exception of HEU-TH, are more sustainable than a PWR fuel cycle. With LEU-NV being the most sustainable commercial options. In addition, all commercial MHR options out perform the PWR with regards to its proliferation-resistance, with thorium fuel cycle having the best proliferation-resistance characteristics.

  19. Inorganic nitrogen transformations in the bed of the Shingobee River, Minnesota: Integrating hydrologic and biological processes using sediment perfusion cores

    Science.gov (United States)

    Sheibley, R.W.; Duff, J.H.; Jackman, A.P.; Triska, F.J.

    2003-01-01

    Inorganic N transformations were examined in streambed sediments from the Shingobee River using sediment perfusion cores. The experimental design simulated groundwater-stream water mixing within sediment cores, which provided a well-defined one-dimensional representation of in situ hydrologic conditions. Two distinct hydrologic and chemical settings were preserved in the sediment cores: the lowermost sediments, perfused with groundwater, remained anaerobic during the incubations, whereas the uppermost sediments, perfused with oxic water pumped from the overlying water column, simulated stream water penetration into the bed. The maintenance of oxic and anoxic zones formed a biologically active aerobic-anaerobic interface. Ammonium (NH4+) dissolved in groundwater was transported conservatively through the lower core zone but was removed as it mixed with aerated recycle water. Concurrently, a small quantity of nitrate (NO3-) equaling ???25% of the NH4+ loss was produced in the upper sediments. The NH4+ and NO3- profiles in the uppermost sediments resulted from coupled nitrification-denitrification, because assimilation and sorption were negligible. We hypothesize that anaerobic microsites within the aerated upper sediments supported denitrification. Rates of nitrification and denitrification in the perfusion cores ranged 42-209 and 53-160 mg N m-2 day-1, respectively. The use of modified perfusion cores permitted the identification and quantification of N transformations and verified process control by surface water exchange into the shallow hyporheic zone of the Shingobee River.

  20. Estimation and control in HTGR fuel rod fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Downing, D J; Bailey, M J

    1980-01-01

    A control algorithm has been derived for a HTGR Fuel Rod Fabrication Process utilizing the method of Box and Jenkins. The estimator is a Kalman filter and is compared with a Least Square estimator and a standard control chart. The effects of system delays are presented.

  1. Physical Analysis of the Initial Core and Running-In Phase for Pebble-Bed Reactor HTR-PM

    Directory of Open Access Journals (Sweden)

    Jingyu Zhang

    2017-01-01

    Full Text Available The pebble-bed reactor HTR-PM is being built in China and is planned to be critical in one or two years. At present, one emphasis of engineering design is to determine the fuel management scheme of the initial core and running-in phase. There are many possible schemes, and many factors need to be considered in the process of scheme evaluation and analysis. Based on the experience from the constructed or designed pebble-bed reactors, the fuel enrichment and the ratio of fuel spheres to graphite spheres are important. In this paper, some relevant physical considerations of the initial core and running-in phase of HTR-PM are given. Then a typical scheme of the initial core and running-in phase is proposed and simulated with VSOP code, and some key physical parameters, such as the maximum power per fuel sphere, the maximum fuel temperature, the refueling rate, and the discharge burnup, are calculated. Results of the physical parameters all satisfy the relevant design requirements, which means the proposed scheme is safe and reliable and can provide support for the fuel management of HTR-PM in the future.

  2. The Pebble Bed Modular Reactor: An obituary

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Steve, E-mail: stephen.thomas@gre.ac.u [Public Services International Research Unit (PSIRU), Business School, University of Greenwich, 30 Park Row, London SE10 9LS (United Kingdom)

    2011-05-15

    The High Temperature Gas-cooled Reactor (HTGR) has exerted a peculiar attraction over nuclear engineers. Despite many unsuccessful attempts over half a century to develop it as a commercial power reactor, there is still a strong belief amongst many nuclear advocates that a highly successful HTGR technology will emerge. The most recent attempt to commercialize an HTGR design, the Pebble Bed Modular Reactor (PBMR), was abandoned in 2010 after 12 years of effort and the expenditure of a large amount of South African public money. This article reviews this latest attempt to commercialize an HTGR design and attempts to identify which issues have led to its failure and what lessons can be learnt from this experience. It concludes that any further attempts to develop HTGRs using Pebble Bed technology should only be undertaken if there is a clear understanding of why earlier attempts have failed and a high level of confidence that earlier problems have been overcome. It argues that the PBMR project has exposed serious weaknesses in accountability mechanisms for the expenditure of South African public money. - Research highlights: {yields} In this study we examine the reasons behind the failure of the South African PBMR programme. {yields} The study reviews the technical issues that have arisen and lessons for future reactor developments. {yields} The study also identifies weaknesses in the accountability mechanisms for public spending.

  3. KUGEL: a thermal, hydraulic, fuel performance, and gaseous fission product release code for pebble bed reactor core analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shamasundar, B.I.; Fehrenbach, M.E.

    1981-05-01

    The KUGEL computer code is designed to perform thermal/hydraulic analysis and coated-fuel particle performance calculations for axisymmetric pebble bed reactor (PBR) cores. This computer code was developed as part of a Department of Energy (DOE)-funded study designed to verify the published core performance data on PBRs. The KUGEL code is designed to interface directly with the 2DB code, a two-dimensional neutron diffusion code, to obtain distributions of thermal power, fission rate, fuel burnup, and fast neutron fluence, which are needed for thermal/hydraulic and fuel performance calculations. The code is variably dimensioned so that problem size can be easily varied. An interpolation routine allows variable mesh size to be used between the 2DB output and the two-dimensional thermal/hydraulic calculations.

  4. EFFECTS OF GRAPHITE SURFACE ROUGHNESS ON BYPASS FLOW COMPUTATIONS FOR AN HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Rich Johnson; Yu-Hsin Tung; Hiroyuki Sato

    2011-07-01

    Bypass flow in a prismatic high temperature gas reactor (HTGR) occurs between graphite blocks as they sit side by side in the core. Bypass flow is not intentionally designed to occur in the reactor, but is present because of tolerances in manufacture, imperfect installation and expansion and shrinkage of the blocks from heating and irradiation. It is desired to increase the knowledge of the effects of such flow, which has been estimated to be as much as 20% of the total helium coolant flow. Computational fluid dynamic (CFD) simulations can provide estimates of the scale and impacts of bypass flow. Previous CFD calculations have examined the effects of bypass gap width, level and distribution of heat generation and effects of shrinkage. The present contribution examines the effects of graphite surface roughness on the bypass flow for different relative roughness factors on three gap widths. Such calculations should be validated using specific bypass flow measurements. While such experiments are currently underway for the specific reference prismatic HTGR design for the next generation nuclear plant (NGNP) program of the U. S. Dept. of Energy, the data are not yet available. To enhance confidence in the present calculations, wall shear stress and heat transfer results for several turbulence models and their associated wall treatments are first compared for flow in a single tube that is representative of a coolant channel in the prismatic HTGR core. The results are compared to published correlations for wall shear stress and Nusselt number in turbulent pipe flow. Turbulence models that perform well are then used to make bypass flow calculations in a symmetric onetwelfth sector of a prismatic block that includes bypass flow. The comparison of shear stress and Nusselt number results with published correlations constitutes a partial validation of the CFD model. Calculations are also compared to ones made previously using a different CFD code. Results indicate that

  5. Innovative safety features of the modular HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Silady, F.A.; Simon, W.A.

    1992-04-01

    In this document the innovative safety features of the MHTGR are reviewed by examining the safety response to events challenging the functions relied on to retain radionuclides within the coated fuel particles. A broad range of challenges to core heat removal are examined, including a loss of helium pressure and a simultaneous loss of forced cool of the core.

  6. HTGR fuel recycle development program. Quarterly progress report for the period ending August 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1978-09-01

    The work reported includes the development of unit processes and equipment for reprocessing of High-Temperature Gas-Cooled Reactor (HTGR) fuel, the design and development of an integrated pilot line to demonstrate the head end of HTGR reprocessing using unirradiated fuel materials, and design work in support of Hot Engineering Tests (HET). Work is also described on tradeoff studies concerning the required design of facilities and equipment for the large-scale recycle of HTGR fuels in order to guide the development activities for HTGR fuel recycle.

  7. HTGR Generic Technology Program. Semiannual report for the period ending September 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-01

    This document reports the technical accomplishments on the HTGR Generic Technology Program at General Atomic during the second half of FY-80. It covers a period when the design direction of the National HTGR Program is in the process of an overall review. The HTGR Generic Technology Program activities have continued so as to provide the basic technology required for all HTGR applications. The activities include the need to develop an LEU fuel and the need to qualify materials and components for the higher temperatures of the gas turbines and process heat plants.

  8. Improved gas distributor for coating HTGR fuel particles

    Energy Technology Data Exchange (ETDEWEB)

    Lackey, W. J.; Stinton, D. P.; Sease, J. D.

    1977-01-01

    A new and improved gas distributor was developed for use in coating fuel particles for the HTGR. The coating gas enters the coating furnace through multiple thin regions of a porous plate. This more uniformly disperses the gas and leads to improved coating properties. High-quality carbon and SiC coatings have been deposited with the new distributor in both 13- and 24-cm-diam coating furnaces.

  9. IAEA Coordinated Research Project on HTGR Reactor Physics, Thermal-hydraulics and Depletion Uncertainty Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Strydom, Gerhard [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bostelmann, F. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    The continued development of High Temperature Gas Cooled Reactors (HTGRs) requires verification of HTGR design and safety features with reliable high fidelity physics models and robust, efficient, and accurate codes. The predictive capability of coupled neutronics/thermal-hydraulics and depletion simulations for reactor design and safety analysis can be assessed with sensitivity analysis (SA) and uncertainty analysis (UA) methods. Uncertainty originates from errors in physical data, manufacturing uncertainties, modelling and computational algorithms. (The interested reader is referred to the large body of published SA and UA literature for a more complete overview of the various types of uncertainties, methodologies and results obtained). SA is helpful for ranking the various sources of uncertainty and error in the results of core analyses. SA and UA are required to address cost, safety, and licensing needs and should be applied to all aspects of reactor multi-physics simulation. SA and UA can guide experimental, modelling, and algorithm research and development. Current SA and UA rely either on derivative-based methods such as stochastic sampling methods or on generalized perturbation theory to obtain sensitivity coefficients. Neither approach addresses all needs. In order to benefit from recent advances in modelling and simulation and the availability of new covariance data (nuclear data uncertainties) extensive sensitivity and uncertainty studies are needed for quantification of the impact of different sources of uncertainties on the design and safety parameters of HTGRs. Only a parallel effort in advanced simulation and in nuclear data improvement will be able to provide designers with more robust and well validated calculation tools to meet design target accuracies. In February 2009, the Technical Working Group on Gas-Cooled Reactors (TWG-GCR) of the International Atomic Energy Agency (IAEA) recommended that the proposed Coordinated Research Program (CRP) on

  10. Application of Dredged Materials and Steelmaking Slag as Basal Media to Restore and Create Seagrass Beds: Mesocosm and Core Incubation Experiments

    Science.gov (United States)

    Tsukasaki, A.; Suzumura, M.; Tsurushima, N.; Nakazato, T.; Huang, Y.; Tanimoto, T.; Yamada, N.; Nishijima, W.

    2016-02-01

    Seagrass beds stabilize bottom sediments, improve water quality and light conditions, enhance species diversity, and provide habitat complexity in coastal marine environments. Seagrass beds are now experiencing worldwide decline by rapid environmental changes. Possible options of seagrass bed restoration are civil engineering works including mounding to raise the bottom to elevations with suitable light for seagrass growth. Reuse or recycling of dredged materials (DM) and various industrial by-products including steelmaking slags is a beneficial option to restore and create seagrass beds. To evaluate the applicability of DM and dephosphorization slag (Slag) as basal media of seagrass beds, we carried out mesocosm experiments and core incubation experiments in a land-based flow-through seawater tank over a year. During the mesocosm experiment, no difference was found in growth of eelgrass (Zostera marina L.) and macrobenthic community structures between Slag-based sediments and sand-based control experiments, even though Slag-based sediments exhibited substantially higher pH than sand-based sediments. During the core incubation experiment, we investigated detailed variation and distributions of pH and nutrients, and diffusion fluxes of nutrients between the sediment/seawater interface. Though addition of Slag induced high pH up to 10.7 in deep layers (reported in natural coastal systems. It was suggested that the mixture of Slag and DM is applicable as basal media for construction of artificial seagrass beds.

  11. HTGR-INTEGRATED COAL TO LIQUIDS PRODUCTION ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Anastasia M Gandrik; Rick A Wood

    2010-10-01

    As part of the DOE’s Idaho National Laboratory (INL) nuclear energy development mission, the INL is leading a program to develop and design a high temperature gas-cooled reactor (HTGR), which has been selected as the base design for the Next Generation Nuclear Plant. Because an HTGR operates at a higher temperature, it can provide higher temperature process heat, more closely matched to chemical process temperatures, than a conventional light water reactor. Integrating HTGRs into conventional industrial processes would increase U.S. energy security and potentially reduce greenhouse gas emissions (GHG), particularly CO2. This paper focuses on the integration of HTGRs into a coal to liquids (CTL) process, for the production of synthetic diesel fuel, naphtha, and liquefied petroleum gas (LPG). The plant models for the CTL processes were developed using Aspen Plus. The models were constructed with plant production capacity set at 50,000 barrels per day of liquid products. Analysis of the conventional CTL case indicated a potential need for hydrogen supplementation from high temperature steam electrolysis (HTSE), with heat and power supplied by the HTGR. By supplementing the process with an external hydrogen source, the need to “shift” the syngas using conventional water-gas shift reactors was eliminated. HTGR electrical power generation efficiency was set at 40%, a reactor size of 600 MWth was specified, and it was assumed that heat in the form of hot helium could be delivered at a maximum temperature of 700°C to the processes. Results from the Aspen Plus model were used to perform a preliminary economic analysis and a life cycle emissions assessment. The following conclusions were drawn when evaluating the nuclear assisted CTL process against the conventional process: • 11 HTGRs (600 MWth each) are required to support production of a 50,000 barrel per day CTL facility. When compared to conventional CTL production, nuclear integration decreases coal

  12. Recent developments in graphite. [Use in HTGR and aerospace

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, J.E.

    1983-01-01

    Overall, the HTGR graphite situation is in excellent shape. In both of the critical requirements, fuel blocks and support structures, adequate graphites are at hand and improved grades are sufficiently far along in truncation. In the aerospace field, GraphNOL N3M permits vehicle performance with confidence in trajectories unobtainable with any other existing material. For fusion energy applications, no other graphite can simultaneously withstand both extreme thermal shock and neutron damage. Hence, the material promises to create new markets as well as to offer a better candidate material for existing applications.

  13. Project summary plan for HTGR recycle reference facility

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, B.J.

    1979-11-01

    A summary plan is introduced for completing conceptual definition of an HTGR Recycle Reference Facility (HRRF). The plan describes a generic project management concept, often referred to as the requirements approach to systems engineering. The plan begins with reference flow sheets and provides for the progressive evolution of HRRF requirements and definition through feasibility, preconceptual, and conceptual phases. The plan lays end-to-end all the important activities and elements to be treated during each phase of design. Identified activities and elements are further supported by technical guideline documents, which describe methodology, needed terminology, and where relevant a worked example.

  14. HTR-PROTEUS Pebble Bed Experimental Program Cores 1, 1A, 2, and 3: Hexagonal Close Packing with a 1:2 Moderator-to-Fuel Pebble Ratio

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Barbara H. Dolphin; James W. Sterbentz; Luka Snoj; Igor Lengar; Oliver Köberl

    2013-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. Four benchmark experiments were evaluated in this report: Cores 1, 1A, 2, and 3. These core configurations represent the hexagonal close packing (HCP) configurations of the HTR-PROTEUS experiment with a moderator-to-fuel pebble ratio of 1:2. Core 1 represents the only configuration utilizing ZEBRA control rods. Cores 1A, 2, and 3 use withdrawable, hollow, stainless steel control rods. Cores 1 and 1A are similar except for the use of different control rods; Core 1A also has one less layer of pebbles (21 layers instead of 22). Core 2 retains the first 16 layers of pebbles from Cores 1 and 1A and has 16 layers of moderator pebbles stacked above the fueled layers. Core 3 retains the first 17 layers of pebbles but has polyethylene rods inserted between pebbles to simulate water ingress. The additional partial pebble layer (layer 18) for Core 3 was not included as it was used for core operations and not the reported critical configuration. Cores 1, 1A, 2, and 3 were determined to be acceptable benchmark experiments.

  15. HTR-PROTEUS Pebble Bed Experimental Program Cores 1, 1A, 2, and 3: Hexagonal Close Packing with a 1:2 Moderator-to-Fuel Pebble Ratio

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Barbara H. Dolphin; James W. Sterbentz; Luka Snoj; Igor Lengar; Oliver Köberl

    2012-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. Four benchmark experiments were evaluated in this report: Cores 1, 1A, 2, and 3. These core configurations represent the hexagonal close packing (HCP) configurations of the HTR-PROTEUS experiment with a moderator-to-fuel pebble ratio of 1:2. Core 1 represents the only configuration utilizing ZEBRA control rods. Cores 1A, 2, and 3 use withdrawable, hollow, stainless steel control rods. Cores 1 and 1A are similar except for the use of different control rods; Core 1A also has one less layer of pebbles (21 layers instead of 22). Core 2 retains the first 16 layers of pebbles from Cores 1 and 1A and has 16 layers of moderator pebbles stacked above the fueled layers. Core 3 retains the first 17 layers of pebbles but has polyethylene rods inserted between pebbles to simulate water ingress. The additional partial pebble layer (layer 18) for Core 3 was not included as it was used for core operations and not the reported critical configuration. Cores 1, 1A, 2, and 3 were determined to be acceptable benchmark experiments.

  16. Preliminary Study of the Supercritical CO{sub 2} Hybrid Cycle for the HTGR Application

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Seong Jun; Ahn, Yoonhan; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    This study was conducted to explore the potential of Supercritical Carbon Dioxide (S-CO{sub 2}) Brayton cycle for the HTGR application. The S-CO{sub 2} cycle is being considered as a PCS due to its high thermal efficiency, simplicity, compactness and so on. Generally, the S-CO{sub 2} Brayton cycle is characterized as a highly recuperated cycle which means that to achieve high thermal efficiency, the cycle requires a highly effective recuperator. Argonne National Laboratory (ANL) showed that direct application of the standard S-CO{sub 2} recompressing Brayton cycle to the HTGR or the Very High Temperature Reactor (VHTR) is difficult to achieve high thermal efficiency due to the mismatch of the temperature difference between the temperature drop of helium as the primary reactor coolant and the temperature rise of CO{sub 2} as the PCS coolant through an Intermediate Heat Exchanger (IHX). Therefore, our research team suggests a novel S-CO{sub 2} cycle configuration, the S-CO{sub 2} Brayton and Rankine hybrid cycle, to solve this limitation. This S-CO{sub 2} hybrid concept is utilizing the waste heat of the S-CO{sub 2} Brayton cycle as heat input to the S-CO{sub 2} Rankine cycle. Dividing the thermal capacity of the heat source in to the Brayton cycle part and Rankine cycle part of the S-CO{sub 2} hybrid cycle appropriately, the temperature difference at the IHX could be reduced, therefore the net system performance and operating range can be improved. In this study, the ANL research is reviewed by the in-house cycle analysis codes developed by the Korea Advanced Institute of Science and Technology (KAIST) research team. And the S-CO{sub 2} Brayton and Rankine hybrid cycle is studied as a PCS for the VHTR condition which was utilized by ANL research team; it was assumed that the core outlet temperature to be 850 .deg. C and the core inlet temperature of 400 .deg. C.

  17. One-dimensional modeling of radial heat removal during depressurized heatup transients in modular pebble-bed and prismatic high temperature gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Savage, M.G.

    1984-07-01

    A one-dimensional computational model was developed to evaluate the heat removal capabilities of both prismatic-core and pebble-bed modular HTGRs during depressurized heatup transients. A correlation was incorporated to calculate the temperature- and neutron-fluence-dependent thermal conductivity of graphite. The modified Zehner-Schluender model was used to determine the effective thermal conductivity of a pebble bed, accounting for both conduction and radiation. Studies were performed for prismatic-core and pebble-bed modular HTGRs, and the results were compared to analyses performed by GA and GR, respectively. For the particular modular reactor design studied, the prismatic HTGR peak temperature was 2152.2/sup 0/C at 38 hours following the transient initiation, and the pebble-bed peak temperature was 1647.8/sup 0/C at 26 hours. These results compared favorably with those of GA and GE, with only slight differences caused by neglecting axial heat transfer in a one-dimensional radial model. This study found that the magnitude of the initial power density had a greater effect on the temperature excursion than did the initial temperature.

  18. Preliminary design of 600 MWt HTGR-gas turbine plant

    Energy Technology Data Exchange (ETDEWEB)

    Muto, Yasushi; Miyamoto, Yoshiaki; Shiozawa, Shusaku [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    1999-07-01

    In JAERI a feasibility study of the High Temperature Gas-cooled Reactor - Gas Turbine (HTGR-GT) system has been carried out since January, 1997 as an assigned work by the Science and Technology Agency. This paper describes a result of a preliminary design for a direct cycle plant of 600 MWt carried out in 1997 fiscal year within the framework of this feasibility study. A reactor inlet gas temperature of 460degC, a reactor outlet gas temperature of 850degC and a helium gas pressure of 6 MPa were selected. A power density of 6 MW/m{sup 3} and the maximum burnup of 10{sup 5} MWD/ton were achieved. A single-shaft horizontal turbomachine of 3600 rpm was selected and placed in a turbine vessel. A net thermal efficiency of 45.7% is expected to be achieved. (author)

  19. Chemical thermodynamics of iodine species in the HTGR fuel particle

    Energy Technology Data Exchange (ETDEWEB)

    Lindemer, T.B.

    1982-09-01

    The iodine-containing species in an intact fuel particle in the high-temperature gas-cooled reactor (HTGR) have been calculated. Assumptions include: (1) attainment of chemical thermodynamic equilibrium among all species in the open porosity of the particle, primarily in the buffer layer; and (2) fission-product concentrations in proportion to their yields. The primary gaseous species is calculated to be cesium iodide; in carbide-containing fuels, gaseous barium iodide may exhibit equivalent pressures. The condensed iodine-containing phase is usually cesium iodide, but in carbide-containing fuels, barium iodide may be stable instead. Absorption of elemental iodine on the carbon in the particle appears to be less than or equal to 10/sup -4/ ..mu..g I/g C. The fission-product-spectra excess of cesium over iodine would generally be adsorbed on the carbon, but may form Cs/sub 2/MoO/sub 4/ under some circumstances.

  20. Fort Saint Vrain HTGR (Th/U carbide) Fuel Characteristics for Disposal Criticality Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Larry Lorin

    2001-01-01

    DOE-owned spent nuclear fuels encompass many fuel types. In an effort to facilitate criticality analysis for these various fuel types, they were categorized into eight characteristic fuel groups with emphasis on fuel matrix composition. Out of each fuel group, a representative fuel type was chosen for analysis as a bounding case within that fuel group. Generally, burnup data, fissile enrichments and total fuel mass govern the selection of the representative or candidate fuel within that group. For the HTGR group, the Fort Saint Vrain (FSV) reactor fuel has been chosen for the evaluation of viability for waste co-disposal. The FSV reactor was operated by Public Service of Colorado as a licensed power reactor. The FSV fuel employs a U/Th carbide matrix in individually pyrolytic carbon-coated particles. These individual particles are in turn coated with silicon carbide (SiC) and contained within fuel compacts, that are in turn embedded in graphite blocks that comprised the structural core of the reactor.

  1. The reprocessing of reactor core materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing, E-mail: wang-jing@nuaa.edu.cn [State Key Laboratory of Mechanics and Control of Mechanial Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Liu, Bing; Shao, Youlin; Lu, Zhenming; Liu, Malin [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

    2014-05-01

    Generation IV high temperature gas-cooled reactors (HTGR) are preferentially fueled by spherical fuel elements, which are composed of a fuel zone of triso-coated uranium oxide (UO{sub 2}) particles and a matrix graphite layer. Unqualified coated particles and spherical fuel elements unavoidablely occur during the processing of coating UO{sub 2} kernels and embedding the coated particles into the graphite matrix. So it is necessary to reprocess the UO{sub 2} in the unqualified coated particles and spherical fuel elements to maximize the use of the reactor core materials. In this work, we present several methods to: (1) separate the coated particles from the graphite matrix and, (2) expose and recover the UO{sub 2} kernels from the coated particles. The comparison of different methods shows that the thermal oxidation of graphite by a fixed bed burner and the jet grinding of the unqualified coated particles are prosing in practice for the separation of coated particles from the graphite matrix and recovering the uranium dioxide kernels, respectively. Some other methods, such as etching the SiC layer with the active fluorine species in plasma generated by the dielectric barrier discharge (DBD) under the atmosphere also show their great potential values in the reprocessing of reactor core materials, especially for the activated and contaminated fuels.

  2. The IAEA Coordinated Research Program on HTGR Reactor Physics, Thermal-hydraulics and Depletion Uncertainty Analysis: Description of the Benchmark Test Cases and Phases

    Energy Technology Data Exchange (ETDEWEB)

    Frederik Reitsma; Gerhard Strydom; Bismark Tyobeka; Kostadin Ivanov

    2012-10-01

    The continued development of High Temperature Gas Cooled Reactors (HTGRs) requires verification of design and safety features with reliable high fidelity physics models and robust, efficient, and accurate codes. The uncertainties in the HTR analysis tools are today typically assessed with sensitivity analysis and then a few important input uncertainties (typically based on a PIRT process) are varied in the analysis to find a spread in the parameter of importance. However, one wish to apply a more fundamental approach to determine the predictive capability and accuracies of coupled neutronics/thermal-hydraulics and depletion simulations used for reactor design and safety assessment. Today there is a broader acceptance of the use of uncertainty analysis even in safety studies and it has been accepted by regulators in some cases to replace the traditional conservative analysis. Finally, there is also a renewed focus in supplying reliable covariance data (nuclear data uncertainties) that can then be used in uncertainty methods. Uncertainty and sensitivity studies are therefore becoming an essential component of any significant effort in data and simulation improvement. In order to address uncertainty in analysis and methods in the HTGR community the IAEA launched a Coordinated Research Project (CRP) on the HTGR Uncertainty Analysis in Modelling early in 2012. The project is built on the experience of the OECD/NEA Light Water Reactor (LWR) Uncertainty Analysis in Best-Estimate Modelling (UAM) benchmark activity, but focuses specifically on the peculiarities of HTGR designs and its simulation requirements. Two benchmark problems were defined with the prismatic type design represented by the MHTGR-350 design from General Atomics (GA) while a 250 MW modular pebble bed design, similar to the INET (China) and indirect-cycle PBMR (South Africa) designs are also included. In the paper more detail on the benchmark cases, the different specific phases and tasks and the latest

  3. A 454 survey reveals the community composition and core microbiome of the common bed bug (Cimex lectularius) across an Urban Landscape.

    Science.gov (United States)

    Meriweather, Matthew; Matthews, Sara; Rio, Rita; Baucom, Regina S

    2013-01-01

    Elucidating the spatial dynamic and core constituents of the microbial communities found in association with arthropod hosts is of crucial importance for insects that may vector human or agricultural pathogens. The hematophagous Cimex lectularius (Hemiptera: Cimicidae), known as the human bed bug, has made a recent resurgence in North America, as well as worldwide, potentially owing to increased travel, climate change and resistance to insecticides. A comprehensive survey of the bed bug microbiome has not been performed to date, nor has an assessment of the spatial dynamics of its microbiome. Here we present a survey of internal and external bed bug microbial communities by amplifying the V4-V6 hypervariable region of the 16S rDNA gene region followed by 454 Titanium sequencing using 31 individuals from eight distinct collection locations obtained from residences in Cincinnati, OH. Across all samples, 97% of the microbial community is made up of two dominant OTUs, previously identified as the α-proteobacterium Wolbachia and an unnamed γ-proteobacterium from the Enterobacteriaceae. Microbial communities varied among host locations for measures of community diversity and exhibited structure according to collection location. This broad survey represents the most in-depth assessment, to date, of the microbes that associate with bed bugs.

  4. A 454 survey reveals the community composition and core microbiome of the common bed bug (Cimex lectularius across an Urban Landscape.

    Directory of Open Access Journals (Sweden)

    Matthew Meriweather

    Full Text Available Elucidating the spatial dynamic and core constituents of the microbial communities found in association with arthropod hosts is of crucial importance for insects that may vector human or agricultural pathogens. The hematophagous Cimex lectularius (Hemiptera: Cimicidae, known as the human bed bug, has made a recent resurgence in North America, as well as worldwide, potentially owing to increased travel, climate change and resistance to insecticides. A comprehensive survey of the bed bug microbiome has not been performed to date, nor has an assessment of the spatial dynamics of its microbiome. Here we present a survey of internal and external bed bug microbial communities by amplifying the V4-V6 hypervariable region of the 16S rDNA gene region followed by 454 Titanium sequencing using 31 individuals from eight distinct collection locations obtained from residences in Cincinnati, OH. Across all samples, 97% of the microbial community is made up of two dominant OTUs, previously identified as the α-proteobacterium Wolbachia and an unnamed γ-proteobacterium from the Enterobacteriaceae. Microbial communities varied among host locations for measures of community diversity and exhibited structure according to collection location. This broad survey represents the most in-depth assessment, to date, of the microbes that associate with bed bugs.

  5. HTGR Technology Family Assessment for a Range of Fuel Cycle Missions

    Energy Technology Data Exchange (ETDEWEB)

    Steven J. Piet; Samuel E. Bays; Nick Soelberg

    2010-08-01

    This report examines how the HTGR technology family can provide options for the once through, modified open cycle (MOC), or full recycle fuel cycle strategies. The HTGR can serve all the fuel cycle missions that an LWR can; both are thermal reactors. Additional analyses are warranted to determine if HTGR “full recycle” service could provide improved consumption of transuranic (TRU) material than LWRs (as expected), to analyze the unique proliferation resistance issues associated with the “pebble bed” approach, and to further test and analyze methods to separate TRISO-coated fuel particles from graphite and/or to separate used HTGR fuel meat from its TRISO coating. The feasibility of these two separation issues is not in doubt, but further R&D could clarify and reduce the cost and enable options not adequately explored at present. The analyses here and the now-demonstrated higher fuel burnup tests (after the illustrative designs studied here) should enable future MOC and full recycle HTGR concepts to more rapidly consume TRU, thereby offering waste management advantages. Interest in “limited separation” or “minimum fuel treatment” separation approaches motivates study of impurity-tolerant fuel fabrication. Several issues are outside the scope of this report, including the following: thorium fuel cycles, gas-cooled fast reactors, the reliability of TRISO-coated particles (billions in a reactor), and how soon any new reactor or fuel type could be licensed and then deployed and therefore impact fuel cycle performance measures.

  6. Preliminary experiment design of graphite dust emission measurement under accident conditions for HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Wei, E-mail: pengwei@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China); Chen, Tao; Sun, Qi; Wang, Jie [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China); Yu, Suyuan, E-mail: suyuan@tsinghua.edu.cn [Center for Combustion Energy, The Key Laboratory for Thermal Science and Power Engineering, Ministry of Education, Tsinghua University, Beijing 100084 (China)

    2017-05-15

    Highlights: • A theoretical analysis is used to predict the total graphite dust release for an AVR LOCA. • Similarity criteria must be satisfied between the experiment and the actual HTGR system. • Model experiments should be conducted to predict the graphite dust resuspension rate. - Abstract: The graphite dust movement behavior is significant for the safety analyses of high-temperature gas cooled reactor (HTGR). The graphite dust release for accident conditions is an important source term for HTGR safety analyses. Depressurization release tests are not practical in HTGR because of a radioactivity release to the environment. Thus, a theoretical analysis and similarity principles were used to design a group of modeling experiments. Modeling experiments for fan start-up and depressurization process and actual experiments of helium circulator start-up in an HTGR were used to predict the rate of graphite dust resuspension and the graphite dust concentration, which can be used to predict the graphite dust release during accidents. The modeling experiments are easy to realize and the helium circulator start-up test does not harm the reactor system or the environment, so this experiment program is easily achieved. The revised Rock’n’Roll model was then used to calculate the AVR reactor release. The calculation results indicate that the total graphite dust releases during a LOCA will be about 0.65 g in AVR.

  7. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORE 4: RANDOM PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Leland M. Montierth

    2013-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. One benchmark experiment was evaluated in this report: Core 4. Core 4 represents the only configuration with random pebble packing in the HTR-PROTEUS series of experiments, and has a moderator-to-fuel pebble ratio of 1:1. Three random configurations were performed. The initial configuration, Core 4.1, was rejected because the method for pebble loading, separate delivery tubes for the moderator and fuel pebbles, may not have been completely random; this core loading was rejected by the experimenters. Cores 4.2 and 4.3 were loaded using a single delivery tube, eliminating the possibility for systematic ordering effects. The second and third cores differed slightly in the quantity of pebbles loaded (40 each of moderator and fuel pebbles), stacked height of the pebbles in the core cavity (0.02 m), withdrawn distance of the stainless steel control rods (20 mm), and withdrawn distance of the autorod (30 mm). The 34 coolant channels in the upper axial reflector and the 33 coolant channels in the lower axial reflector were open. Additionally, the axial graphite fillers used in all other HTR-PROTEUS configurations to create a 12-sided core cavity were not used in the randomly packed cores. Instead, graphite fillers were placed on the cavity floor, creating a funnel-like base, to discourage ordering

  8. HTR-proteus pebble bed experimental program core 4: random packing with a 1:1 moderator-to-fuel pebble ratio

    Energy Technology Data Exchange (ETDEWEB)

    Bess, John D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Montierth, Leland M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sterbentz, James W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Briggs, J. Blair [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gougar, Hans D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Snoj, Luka [Jozef Stefan Inst. (IJS), Ljubljana (Slovenia); Lengar, Igor [Jozef Stefan Inst. (IJS), Ljubljana (Slovenia); Koberl, Oliver [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    2014-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. One benchmark experiment was evaluated in this report: Core 4. Core 4 represents the only configuration with random pebble packing in the HTR-PROTEUS series of experiments, and has a moderator-to-fuel pebble ratio of 1:1. Three random configurations were performed. The initial configuration, Core 4.1, was rejected because the method for pebble loading, separate delivery tubes for the moderator and fuel pebbles, may not have been completely random; this core loading was rejected by the experimenters. Cores 4.2 and 4.3 were loaded using a single delivery tube, eliminating the possibility for systematic ordering effects. The second and third cores differed slightly in the quantity of pebbles loaded (40 each of moderator and fuel pebbles), stacked height of the pebbles in the core cavity (0.02 m), withdrawn distance of the stainless steel control rods (20 mm), and withdrawn distance of the autorod (30 mm). The 34 coolant channels in the upper axial reflector and the 33 coolant channels in the lower axial reflector were open. Additionally, the axial graphite fillers used in all other HTR-PROTEUS configurations to create a 12-sided core cavity were not used in the randomly packed cores. Instead, graphite fillers were placed on the cavity floor, creating a funnel-like base, to discourage ordering

  9. Probabilistic risk assessment of the modular HTGR plant. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Everline, C.J.; Bellis, E.A.; Vasquez, J.

    1986-06-01

    A preliminary probabilistic risk assessment (PRA) has been performed for the modular HTGR (MHTGR). This PRA is preliminary in the context that although it updates the PRA issued earlier to include a wider spectrum of events for Licensing Basis Events (LBE) selection, the final version will not be issued until later. The primary function of the assessment was to assure compliance with the NRC interim safety goals imposed by the top-level regulatory criteria, and utility/user requirements regarding public evacuation or sheltering. In addition, the assessment provides a basis for designer feedback regarding reliability allocations and barrier retention requirements as well as providing a basis for the selection of licensing basis events (LBEs) and the safety classification of structures, systems, and components. The assessment demonstrates that both the NRC interim safety goals and utility/user imposed sheltering/evacuation requirements are satisfied. Moreover, it is not anticipated that design changes introduced will jeopardize compliance with the interim safety goals or utility/user requirements. 61 refs., 48 figs., 24 tabs.

  10. Fission-product SiC reaction in HTGR fuel

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, F.

    1981-07-13

    The primary barrier to release of fission product from any of the fuel types into the primary circuit of the HTGR are the coatings on the fuel particles. Both pyrolytic carbon and silicon carbide coatings are very effective in retaining fission gases under normal operating conditions. One of the possible performance limitations which has been observed in irradiation tests of TRISO fuel is chemical interaction of the SiC layer with fission products. This reaction reduces the thickness of the SiC layer in TRISO particles and can lead to release of fission products from the particles if the SiC layer is completely penetrated. The experimental section of this report describes the results of work at General Atomic concerning the reaction of fission products with silicon carbide. The discussion section describes data obtained by various laboratories and includes (1) a description of the fission products which have been found to react with SiC; (2) a description of the kinetics of silicon carbide thinning caused by fission product reaction during out-of-pile thermal gradient heating and the application of these kinetics to in-pile irradiation; and (3) a comparison of silicon carbide thinning in LEU and HEU fuels.

  11. Chemical thermodynamics of iodine species in the HTGR fuel particle

    Energy Technology Data Exchange (ETDEWEB)

    Lindemer, T.B. (Oak Ridge National Lab., TN (USA))

    The iodine-containing species in an intact fuel particle in the high-temperature gas-cooled reactor (HTGR) have been calculated. Assumptions include: (i) attainment of chemical thermodynamic equilibrium among all species in the open porosity of the particle, primarily in the buffer layer; and (ii) fission-product concentrations in proportion to their yields. The primary gaseous species is calculated to be cesium iodide; in carbide-containing fuels, gaseous barium iodide may exhibit equivalent pressures. The condensed iodine-containing phase is usually cesium iodide, but in carbide-containing fuels, barium iodide may be stable instead. Adsorption of elemental iodine on the carbon in the particle appears to be < 10/sup -4/ ..mu..g I/g C. The fission-product-spectra excess of cesium over iodine would generally be adsorbed on the carbon, but may form Cs/sub 2/MoO/sub 4/ under some circumstances. Equilibria exterior fuel particle have not been analyzed, and may be considerably different from those given above.

  12. IAEA CRP on HTGR Uncertainty Analysis: Benchmark Definition and Test Cases

    Energy Technology Data Exchange (ETDEWEB)

    Gerhard Strydom; Frederik Reitsma; Hans Gougar; Bismark Tyobeka; Kostadin Ivanov

    2012-11-01

    Uncertainty and sensitivity studies are essential elements of the reactor simulation code verification and validation process. Although several international uncertainty quantification activities have been launched in recent years in the LWR, BWR and VVER domains (e.g. the OECD/NEA BEMUSE program [1], from which the current OECD/NEA LWR Uncertainty Analysis in Modelling (UAM) benchmark [2] effort was derived), the systematic propagation of uncertainties in cross-section, manufacturing and model parameters for High Temperature Reactor (HTGR) designs has not been attempted yet. This paper summarises the scope, objectives and exercise definitions of the IAEA Coordinated Research Project (CRP) on HTGR UAM [3]. Note that no results will be included here, as the HTGR UAM benchmark was only launched formally in April 2012, and the specification is currently still under development.

  13. Transport of Residual Nitrogen and Carbon through Intact Soil Cores Amended with Stockpiled Feedlot Manure with Wood-Chip or Straw Bedding.

    Science.gov (United States)

    Miller, J J; Beasley, B W; Drury, C F; Hao, X; Larney, F J

    2013-11-01

    The environmental impact of using wood chips instead of straw bedding with feedlot manure on transport and leaching potential from feedlot manure is unknown. Our main objective was to determine if transport of total N, total organic N, NO-N, and nonpurgeable organic C (NPOC) to subsurface soil was lower for soils amended with feedlot manure if combined with wood chips compared with straw. A secondary objective was to compare transport of N and NPOC with organic amendments versus inorganic fertilizer. Stockpiled feedlot manure (SM) with wood chip (SM-WD) or barley straw (SM-ST) bedding at 39 Mg (dry wt.) ha, and inorganic fertilizer (IN) at 100 kg N ha, was applied annually for 13 yr to a clay loam soil in a replicated field experiment in southern Alberta, Canada. Intact soil cores were taken in fall 2011 (0-30 cm depth) from the three treatments, and the residual N and NPOC were eluted from the soil cores. Total N, total organic N, and NPOC were determined on filtered (1.0 μm) effluent samples that are primarily dissolved fraction but may contain some small particulate N and C. Peak concentrations, flow-weighted mean concentrations, and mass loss of total N, total organic N, NO-N, and NPOC were significantly ( ≤ 0.05) lower by 35 to 86% for SM-WD compared with SM-ST. Mean recoveries were also significantly lower for SM-WD than SM-ST by 0.07 to 8% (absolute difference). The transport behavior was similar for SM-WD and IN treatment, but solute transport was greater for SM-ST than for IN. Application of stockpiled feedlot manure with wood chips instead of straw bedding may be a beneficial management practice to reduce transport and leaching potential of N fractions and NPOC.

  14. Development of a system code for transient analysis in a HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Tae Beom

    2004-02-15

    A GAMMA (GAs Multi-component Multi-dimensional Analysis) code is developed for transient analysis and air ingress analysis in High Temperature Gas-cooled Reactors (HTGR). The PBMR of ESKOM is selected as a reference plant for the High Temperature Gas-cooled Reactor here, which uses a direct helium cycle and pebble fuel. Physical models included in GAMMA are the pebble conduction model, radiation heat transfer model, point kinetics model, decay heat model, and component models for break flow, valve, pump, cooler, power conversion unit model. The temperature distribution and the flow distribution of the PBMR are calculated for initial and accident core in the present study. In the accident analysis, typical design basis accident (DBA), including the load transient accident and depressurization accident into the system are selected and analyzed in detail. The predictions by GAMMA for PBMR at 100% power are compared with those by VSOP and PBR{sub S}IM. It turns out that the temperature in the upper region in the third channel predicted by GAMMA is about 62 .deg. C at maximum higher than that by VSOP, but is pretty close to that by PBR{sub S}IM. The center temperature of the fuel shows that that predicted by considering swelling effect is higher than that without swelling effect by about 10 .deg. C. The net efficiency of direct system is higher than that of indirect system due to an effect of the circulator power. The transient capability of GAMMA is validated through analytical solution and PBR{sub S}IM analyzing the depressurization (Loss Of Coolant Accident, LOCA) and load transient accident. After the LOCA the system pressure decreases dramatically from 8MPa to 0.4MPa within 2 sec. After the PI (Proportional-plus-Integral) controller senses that the power shaft is over the set-point of 3,600 rpm, the bypass valve makes shaft speed back to the set-point.

  15. Methods for calculating group cross sections for doubly heterogeneous thermal reactor systems. [HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Stamatelatos, M G; LaBauve, R J

    1977-02-01

    The report discusses methods used at LASL for calculating group cross sections for doubly heterogeneous HTGR systems of the General Atomic design. These cross sections have been used for the neutronic safety analysis calculations of such HTGR systems at various points in reactor lifetime (e.g., beginning-of-life, end-of-equilibrium cycle). They were also compared with supplied General Atomic cross sections generated with General Atomic codes. The overall agreement between the LASL and the GA cross sections has been satisfactory.

  16. HTGR accident initiation and progression analysis status report. Volume V. AIPA fission product source terms

    Energy Technology Data Exchange (ETDEWEB)

    Alberstein, D.; Apperson, C.E. Jr.; Hanson, D.L.; Myers, B.F.; Pfeiffer, W.W.

    1976-02-01

    The primary objective of the Accident Initiation and Progression Analysis (AIPA) Program is to provide guidance for high-temperature gas-cooled reactor (HTGR) safety research and development. Among the parameters considered in estimating the uncertainties in site boundary doses are uncertainties in fission product source terms generated under normal operating conditions, i.e., fuel body inventories, circulating coolant activity, total plateout activity in the primary circuit, and plateout distributions. The volume presented documents the analyses of these source term uncertainties. The results are used for the detailed consequence evaluations, and they provide the basis for evaluation of fission products important for HTGR maintenance and shielding.

  17. Pebble bed modular reactor safeguards: developing new approaches and implementing safeguards by design

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, Brian David [Los Alamos National Laboratory; Beddingfield, David H [Los Alamos National Laboratory; Durst, Philip [INL; Bean, Robert [INL

    2010-01-01

    The design of the Pebble Bed Modular Reactor (PBMR) does not fit or seem appropriate to the IAEA safeguards approach under the categories of light water reactor (LWR), on-load refueled reactor (OLR, i.e. CANDU), or Other (prismatic HTGR) because the fuel is in a bulk form, rather than discrete items. Because the nuclear fuel is a collection of nuclear material inserted in tennis-ball sized spheres containing structural and moderating material and a PBMR core will contain a bulk load on the order of 500,000 spheres, it could be classified as a 'Bulk-Fuel Reactor.' Hence, the IAEA should develop unique safeguards criteria. In a multi-lab DOE study, it was found that an optimized blend of: (i) developing techniques to verify the plutonium content in spent fuel pebbles, (ii) improving burn-up computer codes for PBMR spent fuel to provide better understanding of the core and spent fuel makeup, and (iii) utilizing bulk verification techniques for PBMR spent fuel storage bins should be combined with the historic IAEA and South African approaches of containment and surveillance to verify and maintain continuity of knowledge of PBMR fuel. For all of these techniques to work the design of the reactor will need to accommodate safeguards and material accountancy measures to a far greater extent than has thus far been the case. The implementation of Safeguards-by-Design as the PBMR design progresses provides an approach to meets these safeguards and accountancy needs.

  18. SPOUTED BED DESIGN CONSIDERATIONS FOR COATED NUCLEAR FUEL PARTICLES

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Douglas W.

    2017-07-01

    High Temperature Gas Cooled Reactors (HTGRs) are fueled with tristructural isotropic (TRISO) coated nuclear fuel particles embedded in a carbon-graphite fuel body. TRISO coatings consist of four layers of pyrolytic carbon and silicon carbide that are deposited on uranium ceramic fuel kernels (350µm – 500µm diameters) in a concatenated series of batch depositions. Each layer has dedicated functions such that the finished fuel particle has its own integral containment to minimize and control the release of fission products into the fuel body and reactor core. The TRISO coatings are the primary containment structure in the HTGR reactor and must have very high uniformity and integrity. To ensure high quality TRISO coatings, the four layers are deposited by chemical vapor deposition (CVD) using high purity precursors and are applied in a concatenated succession of batch operations before the finished product is unloaded from the coating furnace. These depositions take place at temperatures ranging from 1230°C to 1550°C and use three different gas compositions, while the fuel particle diameters double, their density drops from 11.1 g/cm3 to 3.0 g/cm3, and the bed volume increases more than 8-fold. All this is accomplished without the aid of sight ports or internal instrumentation that could cause chemical contamination within the layers or mechanical damage to thin layers in the early stages of each layer deposition. The converging section of the furnace retort was specifically designed to prevent bed stagnation that would lead to unacceptably high defect fractions and facilitate bed circulation to avoid large variability in coating layer dimensions and properties. The gas injection nozzle was designed to protect precursor gases from becoming overheated prior to injection, to induce bed spouting and preclude bed stagnation in the bottom of the retort. Furthermore, the retort and injection nozzle designs minimize buildup of pyrocarbon and silicon carbide on the

  19. Facies And Bedding Analysis of Deep-Marine, Arc-Related, Sediementary Rocks Cored on International Ocean Drilling Program Expedition 351.

    Science.gov (United States)

    Johnson, K. E.; Marsaglia, K. M.

    2015-12-01

    The Izu-Bonin-Mariana (IBM) Arc System, south of Japan, hosts a multitude of active and extinct (remnant) arc volcanic sediment sources. Core extracted adjacent to the proto-IBM arc (Kyushu-Palau Ridge; KPR) in the Amami-Sankaku Basin on International Ocean Discovery Program (IODP) Expedition 351 contains evidence of the variety of sediment sources that have existed in the area as a result of changing tectonic regimes through arc development, backarc basin formation and remnant arc abandonment. Approximately 1000 meters of Eocene to Oligocene volcaniclastic sedimentary rocks were analyzed via shipboard core photos, core descriptions, and thin sections with the intention of understanding the depositional history at this site. These materials contain a crucial record of arc development complementary to the Neogene history preserved in the active reararc (Expedition 350) and compressed whole-arc record in the current forearc (Expedition 352). A database of stratigraphic columns was created to display grain size trends, facies changes, and bedding characteristics. Individual beds (depositional events) were classified using existing and slightly modified classification schemes for muddy, sandy and gravel-rich gravity flow deposits, as well as muddy debris flows and tuffs. Utilizing the deep marine facies classes presented by Pickering et al. (1986), up section changes are apparent. Through time, as the arc developed, facies and bedding types and their proportions change dramatically and relatively abruptly. Following arc initiation facies are primarily mud-rich with intercalated tuffaceous sand. In younger intervals, sand to gravel gravity-flow deposits dominate, becoming more mud-rich. Muddy gravity flow deposits, however, dominate farther upsection. The overall coarsening-upward pattern (Unit III) is consistent with building of the arc edifice. Farther upsection (Unit II) an abrupt fining-upward trend represents the onset of isolation of the KPR as backarc spreading

  20. Safety concerns and suggested design approaches to the HTGR Reformer process concept

    Energy Technology Data Exchange (ETDEWEB)

    Green, R.C.

    1981-09-01

    This report is a safety review of the High Temperature Gas-Cooled Reactor Reformer Application Study prepared by Gas-Cooled Reactor Associates (GCRA) of La Jolla, California. The objective of this review was to identify safety concerns and suggests design approaches to minimize risk in the High Temperature Gas-Cooled Reactor Reformer (HTGR-R) process concept.

  1. CORE

    DEFF Research Database (Denmark)

    Krigslund, Jeppe; Hansen, Jonas; Hundebøll, Martin

    2013-01-01

    different flows. Instead of maintaining these approaches separate, we propose a protocol (CORE) that brings together these coding mechanisms. Our protocol uses random linear network coding (RLNC) for intra- session coding but allows nodes in the network to setup inter- session coding regions where flows...... intersect. Routes for unicast sessions are agnostic to other sessions and setup beforehand, CORE will then discover and exploit intersecting routes. Our approach allows the inter-session regions to leverage RLNC to compensate for losses or failures in the overhearing or transmitting process. Thus, we...... increase the benefits of XORing by exploiting the underlying RLNC structure of individual flows. This goes beyond providing additional reliability to each individual session and beyond exploiting coding opportunistically. Our numerical results show that CORE outperforms both forwarding and COPE...

  2. CORE

    DEFF Research Database (Denmark)

    Krigslund, Jeppe; Hansen, Jonas; Hundebøll, Martin

    2013-01-01

    different flows. Instead of maintaining these approaches separate, we propose a protocol (CORE) that brings together these coding mechanisms. Our protocol uses random linear network coding (RLNC) for intra- session coding but allows nodes in the network to setup inter- session coding regions where flows...... intersect. Routes for unicast sessions are agnostic to other sessions and setup beforehand, CORE will then discover and exploit intersecting routes. Our approach allows the inter-session regions to leverage RLNC to compensate for losses or failures in the overhearing or transmitting process. Thus, we...... increase the benefits of XORing by exploiting the underlying RLNC structure of individual flows. This goes beyond providing additional reliability to each individual session and beyond exploiting coding opportunistically. Our numerical results show that CORE outperforms both forwarding and COPE...

  3. Development of evaluation method with X-ray tomography for material property of IG-430 graphite for VHTR/HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Sumita, Junya, E-mail: sumita.junya@jaea.go.jp [HTGR Design Group Nuclear Hydrogen and Heat Application Research Center, Japan Atomic Energy Agency, 4002 Oarai-machi, Higashiibaraki-gun, Ibaraki-ken 311-1393 (Japan); Shibata, Taiju [Graphite and Carbon Materials Characterization Special Group, Nuclear Engineering Research Collaboration Center, Japan Atomic Energy Agency, 4002 Oarai-machi, Higashiibaraki-gun, Ibaraki-ken, 311-1393 (Japan); Fujita, Ichiro; Kunimoto, Eiji; Yamaji, Masatoshi; Eto, Motokuni; Konishi, Takashi [Atomic Energy Section, Production Division, Toyo Tanso Co., Ltd., 2791 Matsuzaki, Takuma-cho, Mitoyoshi, Kagawa-ken, 769-1102 (Japan); Sawa, Kazuhiro [Department of HTTR, Japan Atomic Energy Agency, Higashiibaraki-gun, Ibaraki-ken 311-1393 (Japan)

    2014-05-01

    Graphite materials are used for the in-core components of High Temperature Gas-cooled Reactor (HTGR) which is a graphite-moderated and helium gas-cooled reactor. The HTGR is particularly attractive due to capability of producing high temperature helium gas, and its passive and inherent safety features. The Very High Temperature Reactor (VHTR) is one of the most promising candidates for the Generation-IV nuclear reactor systems. IG-110 graphite having high strength and resistance to oxidation is used in the HTTR of JAEA. IG-110 is a major candidate for the in-core graphite components of VHTR, too. From the standpoint of the safety at air ingress accident, it is important for graphite materials to have adequate resistance against oxidation damage. IG-430 graphite having higher strength and resistance to oxidation than IG-110 is an advanced candidate for the VHTR. Recently, X-ray tomography method is expected to apply the evaluation of neutron irradiation effects by measuring the irradiation-induced change of geometry of graphite grains and pores. This method is also applicable to evaluate the oxidation damage on graphite from the oxidation-induced change of grain/pore microstructures. In this study, in order to develop evaluation method for material properties and to evaluate the irradiation-induced property changes under higher neutron doses for IG-430, the oxidation and densification effects on elastic modulus of IG-430 were investigated. Moreover, the correlation of the microstructure based on the X-ray tomography images and the material properties was discussed. It was shown that the elastic modulus of the densified graphite depends on only the open pores and it is possible to evaluate the material properties of graphite by using X-ray tomography method. However, it is necessary to take into account of the change in the number and shape of closed pores in the grain to simulate the elastic modulus of the highly oxidized and irradiated materials by the

  4. Recent advances on thermohydraulic simulation of HTR-10 nuclear reactor core using realistic CFD approach

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Alexandro S., E-mail: alexandrossilva@ifba.edu.br [Instituto Federal de Educacao, Ciencia e Tecnologia da Bahia (IFBA), Vitoria da Conquista, BA (Brazil); Mazaira, Leorlen Y.R., E-mail: leored1984@gmail.com, E-mail: cgh@instec.cu [Instituto Superior de Tecnologias y Ciencias Aplicadas (INSTEC), La Habana (Cuba); Dominguez, Dany S.; Hernandez, Carlos R.G., E-mail: alexandrossilva@gmail.com, E-mail: dsdominguez@gmail.com [Universidade Estadual de Santa Cruz (UESC), Ilheus, BA (Brazil). Programa de Pos-Graduacao em Modelagem Computacional; Lira, Carlos A.B.O., E-mail: cabol@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2015-07-01

    High-temperature gas-cooled reactors (HTGRs) have the potential to be used as possible energy generation sources in the near future, owing to their inherently safe performance by using a large amount of graphite, low power density design, and high conversion efficiency. However, safety is the most important issue for its commercialization in nuclear energy industry. It is very important for safety design and operation of an HTGR to investigate its thermal-hydraulic characteristics. In this article, it was performed the thermal-hydraulic simulation of compressible flow inside the core of the pebble bed reactor HTR (High Temperature Reactor)-10 using Computational Fluid Dynamics (CFD). The realistic approach was used, where every closely packed pebble is realistically modelled considering a graphite layer and sphere of fuel. Due to the high computational cost is impossible simulate the full core; therefore, the geometry used is a FCC (Face Centered Cubic) cell with the half height of the core, with 21 layers and 95 pebbles. The input data used were taken from the thermal-hydraulic IAEA Bechmark. The results show the profiles of velocity and temperature of the coolant in the core, and the temperature distribution inside the pebbles. The maximum temperatures in the pebbles do not exceed the allowable limit for this type of nuclear fuel. (author)

  5. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORES 9 & 10: COLUMNAR HEXAGONAL POINT-ON-POINT PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess

    2014-03-01

    PROTEUS is a zero-power research reactor based on a cylindrical graphite annulus with a central cylindrical cavity. The graphite annulus remains basically the same for all experimental programs, but the contents of the central cavity are changed according to the type of reactor being investigated. Through most of its service history, PROTEUS has represented light-water reactors, but from 1992 to 1996 PROTEUS was configured as a pebble-bed reactor (PBR) critical facility and designated as HTR-PROTEUS. The nomenclature was used to indicate that this series consisted of High Temperature Reactor experiments performed in the PROTEUS assembly. During this period, seventeen critical configurations were assembled and various reactor physics experiments were conducted. These experiments included measurements of criticality, differential and integral control rod and safety rod worths, kinetics, reaction rates, water ingress effects, and small sample reactivity effects (Ref. 3). HTR-PROTEUS was constructed, and the experimental program was conducted, for the purpose of providing experimental benchmark data for assessment of reactor physics computer codes. Considerable effort was devoted to benchmark calculations as a part of the HTR-PROTEUS program. References 1 and 2 provide detailed data for use in constructing models for codes to be assessed. Reference 3 is a comprehensive summary of the HTR-PROTEUS experiments and the associated benchmark program. This document draws freely from these references. Only Cores 9 and 10 are evaluated in this benchmark report due to similarities in their construction. The other core configurations of the HTR-PROTEUS program are evaluated in their respective reports as outlined in Section 1.0. Cores 9 and 10 were evaluated and determined to be acceptable benchmark experiments.

  6. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORES 9 & 10: COLUMNAR HEXAGONAL POINT-ON-POINT PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess

    2013-03-01

    PROTEUS is a zero-power research reactor based on a cylindrical graphite annulus with a central cylindrical cavity. The graphite annulus remains basically the same for all experimental programs, but the contents of the central cavity are changed according to the type of reactor being investigated. Through most of its service history, PROTEUS has represented light-water reactors, but from 1992 to 1996 PROTEUS was configured as a pebble-bed reactor (PBR) critical facility and designated as HTR-PROTEUS. The nomenclature was used to indicate that this series consisted of High Temperature Reactor experiments performed in the PROTEUS assembly. During this period, seventeen critical configurations were assembled and various reactor physics experiments were conducted. These experiments included measurements of criticality, differential and integral control rod and safety rod worths, kinetics, reaction rates, water ingress effects, and small sample reactivity effects (Ref. 3). HTR-PROTEUS was constructed, and the experimental program was conducted, for the purpose of providing experimental benchmark data for assessment of reactor physics computer codes. Considerable effort was devoted to benchmark calculations as a part of the HTR-PROTEUS program. References 1 and 2 provide detailed data for use in constructing models for codes to be assessed. Reference 3 is a comprehensive summary of the HTR-PROTEUS experiments and the associated benchmark program. This document draws freely from these references. Only Cores 9 and 10 are evaluated in this benchmark report due to similarities in their construction. The other core configurations of the HTR-PROTEUS program are evaluated in their respective reports as outlined in Section 1.0. Cores 9 and 10 were evaluated and determined to be acceptable benchmark experiments.

  7. Reactivity considerations for the on-line refuelling of a pebble bed modular reactor-Illustrating safety for the most reactive core fuel load

    Energy Technology Data Exchange (ETDEWEB)

    Reitsma, Frederik, E-mail: Frederik.Reitsma@pbmr.co.za [Pebble Bed Modular Reactor (Pty) Ltd., PO Box 9396, Centurion 0043 (South Africa)

    2012-10-15

    In the multi-pass fuel management scheme employed for the pebble bed modular reactor the fuel pebbles are re-circulated until they reach the target burn-up. The rate at which fresh fuel is loaded and burned fuel is discharged is a result of the core neutronics cycle analysis but in practice (on the plant) this has to be controlled and managed by the fuel handling and storage system and use of the burnup measurement system. The excess reactivity is the additional reactivity available in the core during operating conditions that is the result of loading a fuel mixture in the core that is more reactive (less burned) than what is required to keep the reactor critical at full power operational conditions. The excess reactivity is balanced by the insertion of the control rods to keep the reactor critical. The excess reactivity allows flexibility in operations, for example to overcome the xenon build up when power is decreased as part of load follow. In order to limit reactivity excursions and to ensure safe shutdown the excess reactivity and thus the insertion depth of the control rods at normal operating conditions has to be managed. One way to do this is by operational procedures. The reactivity effect of long-term operation with the control rods inserted deeper than the design point is investigated and a control rod insertion limit is proposed that will not limit normal operations. The effects of other phenomena that can increase the power defect, such as higher-than-expected fuel temperatures, are also introduced. All of these cases are then evaluated by ensuring cold shutdown is still achievable and where appropriate by reactivity insertion accident analysis. These aspects are investigated on the PBMR 400 MW design.

  8. Innovative safety features of the modular HTGR. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Silady, F.A.; Simon, W.A.

    1992-04-01

    In this document the innovative safety features of the MHTGR are reviewed by examining the safety response to events challenging the functions relied on to retain radionuclides within the coated fuel particles. A broad range of challenges to core heat removal are examined, including a loss of helium pressure and a simultaneous loss of forced cool of the core.

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

    Energy Technology Data Exchange (ETDEWEB)

    In, W. K.; Lee, S. W.; Lim, H. S.; Lee, W. J. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2006-07-01

    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. A numerical study of helium-heated inorganic membrane reformer coupling to HTGR

    Institute of Scientific and Technical Information of China (English)

    YIN Huaqiang; JIANG Shengyao; JU Huaiming; ZHANG Youjie

    2007-01-01

    Based on one-dimensional quasi-homogeneous model,a steady-state model and its computer program were developed for helium-heated inorganic membrane reformer coupling to high temperature gas-cooled reactor (HTGR).The results show that the average heat flux of inorganic membrane reformer is 25% higher than that of the conventional one.A compact reformer can be designed,which is significant in making the system safer and more economical.A methane conversion rate of 95% can be achieved by inorganic membrane reformer with a little increase in pressure loss.With thinner membrane and higher sweep ratio,methane conversion rate increases with high reforming pressure,which will change the unfavorable condition of high pressure of HTGR methane reforming hydrogen production system into a favorable one.

  11. HTGR high temperature process heat design and cost status report. Volume II. Appendices

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-12-01

    Information is presented concerning the 850/sup 0/C IDC reactor vessel; primary cooling system; secondary helium system; steam generator; heat cycle evaluations for the 850/sup 0/C IDC plant; 950/sup 0/C DC reactor vessel; 950/sup 0/C DC steam generator; direct and indirect cycle reformers; methanation plant; thermochemical pipeline; methodology for screening candidate synfuel processes; ECCG process; project technical requirements; process gas explosion assessment; HTGR program economic guidelines; and vendor respones.

  12. A Small-Sized HTGR System Design for Multiple Heat Applications for Developing Countries

    Directory of Open Access Journals (Sweden)

    Hirofumi Ohashi

    2013-01-01

    Full Text Available Japan Atomic Energy Agency has conducted a conceptual design of a 50 MWt small-sized high temperature gas cooled reactor (HTGR for multiple heat applications, named HTR50S, with the reactor outlet coolant temperature of 750°C and 900°C. It is first-of-a-kind of the commercial plant or a demonstration plant of a small-sized HTGR system to be deployed in developing countries in the 2020s. The design concept of HTR50S is to satisfy the user requirements for multipurpose heat applications such as the district heating and process heat supply based on the steam turbine system and the demonstration of the power generation by helium gas turbine and the hydrogen production using the water splitting iodine-sulfur process, to upgrade its performance compared to that of HTTR without significant R&D utilizing the knowledge obtained by the HTTR design and operation, and to fulfill the high level of safety by utilizing the inherent features of HTGR and a passive decay heat removal system. The evaluation of technical feasibility shows that all design targets were satisfied by the design of each system and the preliminary safety analysis. This paper describes the conceptual design and the preliminary safety analysis of HTR50S.

  13. Prediction of Core-Annulus Solids Mass Transfer Coefficient in Gas-Solid Fluidized Bed Risers%气固循环流化床提升管环核区颗粒质量传递系数的估计

    Institute of Scientific and Technical Information of China (English)

    刘新华; 高士秋; 宋文立

    2005-01-01

    Based on analysis of energy dissipation in the core region of gas-solid fluidized bed risers, a simplified model for determination of core-annulus solids mass transfer coefficient was developed according to turbulent diffusion mechanism of particles. The simulation results are consistent with published experimental data. Core-annulus solids mass transfer coefficient decreases with increasing particle size, particle density and solids circulation rate,but generally increases with increasing superficial gas velocity and riser diameter. In the upper dilute region of gas-solid fluidized bed risers, core-annulus solids mass transfer coefficient was found to change little with the axial coordinate in the bed.

  14. Porosity Effect in the Core Thermal Hydraulics for Ultra High Temperature Gas-cooled Reactor

    Directory of Open Access Journals (Sweden)

    Motoo Fumizawa

    2008-12-01

    Full Text Available This study presents an experimental method of porosity evaluation and a predictive thermal-hydraulic analysis with packed spheres in a nuclear reactor core. The porosity experiments were carried out in both a fully shaken state with the closest possible packing and in a state of non-vibration. The predictive analysis considering the fixed porosity value was applied as a design condition for an Ultra High Temperature Reactor Experiment (UHTREX. The thermal-hydraulic computer code was developed and identified as PEBTEMP. The highest outlet coolant temperature of 1316 oC was achieved in the case of an UHTREX at Los Alamos Scientific Laboratory, which was a small scale UHTR. In the present study, the fuel was changed to a pebble type, a porous media. In order to compare the present pebble bed reactor and UHTREX, a calculation based on HTGR-GT300 was carried out in similar conditions with UHTREX; in other words, with an inlet coolant temperature of 871oC, system pressure of 3.45 MPa and power density of 1.3 w/cm3. As a result, the fuel temperature in the present pebble bed reactor showed an extremely lower value compared to that of UHTREX.

  15. Selected studies in HTGR reprocessing development. [KA2C process

    Energy Technology Data Exchange (ETDEWEB)

    Notz, K.J.

    1976-03-01

    Recent work at ORNL on hot cell studies, off-gas cleanup, and waste handling is reviewed. The work includes small-scale burning tests with irradiated fuels to study fission product release, development of the KALC process for the removal of /sup 85/Kr from a CO/sub 2/ stream, preliminary work on a nonfluidized bed burner, solvent extraction studies including computer modeling, characterization of reprocessing wastes, and initiation of a development program for the fixation of /sup 14/C as CaCO/sub 3/. (auth)

  16. 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.

  17. Creep-Rupture Properties and Corrosion Behaviour of 21/4 Cr-1 Mo Steel and Hastelloy X-Alloys in Simulated HTGR Environment

    DEFF Research Database (Denmark)

    Lystrup, Aage; Rittenhouse, P. L.; DiStefano, J. R.

    Hastelloy X and 2/sup 1///sub 4/ Cr-1 Mo steel are being considered as structural alloys for components of a High-Temperature Gas-Cooled Reactor (HTGR) system. Among other mechanical properties, the creep behavior of these materials in HTGR primary coolant helium must be established to form part ...

  18. An Online Non-Invasive Condition Monitoring Method for Stepping Motor CRDM in HTGR

    Directory of Open Access Journals (Sweden)

    S. Bakhri

    2016-12-01

    Full Text Available Control Rod Drive Mechanism (CRDM based on stepping motor is one of the components applied in High Temperature Gas Coold Reactor (HTGR to control the reactivity as well as to maintain the safety of reactor. The stepping motor requires a unique condition monitoring to avoid any failures especially due to the specific environments of CRDM in HTGR such as the allowable of high temperature, high radiation and the location of stepper motor inside a pressure shell. This research aims to demonstrate an online non-invasive condition monitoring method without direct access to the CRDM of HTGR based on voltage and stator current measurements. A simple stepping motor CRDM simulator is employed. The online condition monitoring is carried out by direct pattern matching of the output signals of logic generator block and the output signals of motor driver. The online method utilizes signature patterns of voltage and stator current signals of the healthy motor as a baseline for healthy motor. In addition, the method is applied to detect high-resistance problem on the connector between the motor driver block and the stepper motor to show the effectiveness and the applicability of this method. The online condition monitoring system demonstrates a capability to identify a minimum detectable simulated high-resistance for about 2.9% which decreases the measured stator current and motor’s torque for around 5.1% and 3.3%, respectively. The paper also points out signatures of healthy motor, including mutual inductions of the motor’s winding in voltage and current measurement which can be used as the fault symptom indicators for online monitoring purposes.

  19. Process behavior and environmental assessment of /sup 14/C releases from an HTGR fuel reprocessing facility

    Energy Technology Data Exchange (ETDEWEB)

    Snider, J.W.; Kaye, S.V.

    1976-01-01

    Large quantities of /sup 14/CO/sub 2/ will be evolved when graphite fuel blocks are burned during reprocessing of spent fuel from HTGR reactors. The possible release of some or all of this /sup 14/C to the environment is a matter of concern which is investigated in this paper. Various alternatives are considered in this study for decontaminating and releasing the process off-gas to the environment. Concomitant radiological analyses have been done for the waste process scenarios to supply the necessary feedbacks for process design.

  20. HTGR plant availability and reliability evaluations. Volume I. Summary of evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Cadwallader, G.J.; Hannaman, G.W.; Jacobsen, F.K.; Stokely, R.J.

    1976-12-01

    The report (1) describes a reliability assessment methodology for systematically locating and correcting areas which may contribute to unavailability of new and uniquely designed components and systems, (2) illustrates the methodology by applying it to such components in a high-temperature gas-cooled reactor (Public Service Company of Colorado's Fort St. Vrain 330-MW(e) HTGR), and (3) compares the results of the assessment with actual experience. The methodology can be applied to any component or system; however, it is particularly valuable for assessments of components or systems which provide essential functions, or the failure or mishandling of which could result in relatively large economic losses.

  1. Thermohydraulic simulation of HTR-10 nuclear reactor core using realistic CFD approach; Simulacao termohidraulica do nucleo do reator nuclear HTR-10 com o uso da abordagem realistica CFD

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Alexandro S.; Dominguez, Dany S., E-mail: alexandrossilva@gmail.com, E-mail: dsdominguez@gmail.com [Universidade Estadual de Santa Cruz (UESC), Ilheus, BA (Brazil); Mazaira, Leorlen Y. Rojas; Hernandez, Carlos R.G., E-mail: leored1984@gmail.com, E-mail: cgh@instec.cu [Instituto Superior de Tecnologias y Ciencias Aplicadas, La Habana (Cuba); Lira, Carlos Alberto Brayner de Oliveira, E-mail: cabol@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2015-07-01

    High-temperature gas-cooled reactors (HTGRs) have the potential to be used as possible energy generation sources in the near future, owing to their inherently safe performance by using a large amount of graphite, low power density design, and high conversion efficiency. However, safety is the most important issue for its commercialization in nuclear energy industry. It is very important for safety design and operation of an HTGR to investigate its thermal–hydraulic characteristics. In this article, it was performed the thermal–hydraulic simulation of compressible flow inside the core of the pebble bed reactor HTR (High Temperature Reactor)-10 using Computational Fluid Dynamics (CFD). The realistic approach was used, where every closely packed pebble is realistically modelled considering a graphite layer and sphere of fuel. Due to the high computational cost is impossible simulate the full core; therefore, the geometry used is a column of FCC (Face Centered Cubic) cells, with 41 layers and 82 pebbles. The input data used were taken from the thermohydraulic IAEA Benchmark (TECDOC-1694). The results show the profiles of velocity and temperature of the coolant in the core, and the temperature distribution inside the pebbles. The maximum temperatures in the pebbles do not exceed the allowable limit for this type of nuclear fuel. (author)

  2. Constitutive modeling and finite element procedure development for stress analysis of prismatic high temperature gas cooled reactor graphite core components

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish, E-mail: smohanty@anl.gov [Argonne National Laboratory, South Cass Avenue, Argonne, IL 60439 (United States); Majumdar, Saurindranath [Argonne National Laboratory, South Cass Avenue, Argonne, IL 60439 (United States); Srinivasan, Makuteswara [U.S. Nuclear Regulatory Commission, Washington, DC 20555 (United States)

    2013-07-15

    Highlights: • Finite element procedure developed for stress analysis of HTGR graphite component. • Realistic fluence profile and reflector brick shape considered for the simulation. • Also realistic H-451 grade material properties considered for simulation. • Typical outer reflector of a GT-MHR type reactor considered for numerical study. • Based on the simulation results replacement of graphite bricks can be scheduled. -- Abstract: High temperature gas cooled reactors, such as prismatic and pebble bed reactors, are increasingly becoming popular because of their inherent safety, high temperature process heat output, and high efficiency in nuclear power generation. In prismatic reactors, hexagonal graphite bricks are used as reflectors and fuel bricks. In the reactor environment, graphite bricks experience high temperature and neutron dose. This leads to dimensional changes (swelling and or shrinkage) of these bricks. Irradiation dimensional changes may affect the structural integrity of the individual bricks as well as of the overall core. The present paper presents a generic procedure for stress analysis of prismatic core graphite components using graphite reflector as an example. The procedure is demonstrated through commercially available ABAQUS finite element software using the option of user material subroutine (UMAT). This paper considers General Atomics Gas Turbine-Modular Helium Reactor (GT-MHR) as a bench mark design to perform the time integrated stress analysis of a typical reflector brick considering realistic geometry, flux distribution and realistic irradiation material properties of transversely isotropic H-451 grade graphite.

  3. 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.

  4. Analytical Results for 35 Mine-Waste Tailings Cores and Six Bed-Sediment Samples, and An Estimate of the Volume of Contaminated Material at Buckeye Meadow on Upper Basin Creek, Northern Jefferson County, Montana

    Science.gov (United States)

    Fey, David L.; Church, Stan E.; Finney, Christopher J.

    1999-01-01

    Metal-mining related wastes in the Boulder River basin study area in northern Jefferson County, Montana have been implicated in their detrimental effects on water quality with regard to acid-generation and toxic-metal solubilization. Flotation-mill tailings in the meadow below the Buckeye mine, hereafter referred to as the Buckeye mill-tailings site, have been identified as significant contributors to water quality degradation of Basin Creek, Montana. Basin Creek is one of three tributaries to the Boulder River in the study area; bed sediments and waters draining from the Buckeye mine have also been implicated. Geochemical analysis of 35 tailings cores and six bed-sediment samples was undertaken to determine the concentrations of Ag, As, Cd, Cu, Pb,and Zn present in these materials. These elements are environmentally significant, in that they can be toxic to fish and/or the invertebrate organisms that constitute their food. A suite of one-inch cores of dispersed flotation-mill tailings and underlying premining material was taken from a large, flat area north of Basin Creek near the site of the Buckeye mine. Thirty-five core samples were taken and divided into 204 subsamples. The samples were analyzed by ICP-AES (inductively coupled plasma-atomic emission spectroscopy) using a mixed-acid digestion. Results of the core analyses show that the elements listed above are present at moderate to very high concentrations (arsenic to 63,000 ppm, silver to 290 ppm, cadmium to 370 ppm, copper to 4,800 ppm, lead to 93,000 ppm, and zinc to 23,000 ppm). Volume calculations indicate that an estimated 8,400 metric tons of contaminated material are present at the site. Six bed-sediment samples were also subjected to the mixed-acid total digestion, and a warm (50°C) 2M HCl-1% H2O2 leach and analyzed by ICP-AES. Results indicate that bed sediments of Basin Creek are only slightly impacted by past mining above the Buckeye-Enterprise complex, moderately impacted at the upper (eastern

  5. Next Generation Nuclear Plant Project Evaluation of Siting a HTGR Co-generation Plant on an Operating Commercial Nuclear Power Plant Site

    Energy Technology Data Exchange (ETDEWEB)

    L.E. Demick

    2011-10-01

    This paper summarizes an evaluation by the Idaho National Laboratory (INL) Next Generation Nuclear Plant (NGNP) Project of siting a High Temperature Gas-cooled Reactor (HTGR) plant on an existing nuclear plant site that is located in an area of significant industrial activity. This is a co-generation application in which the HTGR Plant will be supplying steam and electricity to one or more of the nearby industrial plants.

  6. in Spouted Bed

    Directory of Open Access Journals (Sweden)

    Bronislaw Buczek

    2013-01-01

    Full Text Available Samples of active coke, fresh and spent after cleaning flue gases from communal waste incinerators, were investigated. The outer layers of both coke particles were separately removed by comminution in a spouted bed. The samples of both active cokes were analysed by means of densities, mercury porosimetry, and adsorption technique. Remaining cores were examined to determine the degree of consumption of coke by the sorption of hazardous emissions (SO2, HCl, and heavy metals through its bed. Differences in contamination levels within the porous structure of the particles were estimated. The study demonstrated the effectiveness of commercial active coke in the cleaning of flue gases.

  7. Next Generation Nuclear Plant (NGNP) Prismatic HTGR Conceptual Design Project - Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Saurwein, John

    2011-07-15

    This report is the Final Technical Report for the Next Generation Nuclear Plant (NGNP) Prismatic HTGR Conceptual Design Project conducted by a team led by General Atomics under DOE Award DE-NE0000245. The primary overall objective of the project was to develop and document a conceptual design for the Steam Cycle Modular Helium Reactor (SC-MHR), which is the reactor concept proposed by General Atomics for the NGNP Demonstration Plant. The report summarizes the project activities over the entire funding period, compares the accomplishments with the goals and objectives of the project, and discusses the benefits of the work. The report provides complete listings of the products developed under the award and the key documents delivered to the DOE.

  8. Thermochemical Water Splitting for Hydrogen Production Utilizing Nuclear Heat from an HTGR

    Institute of Scientific and Technical Information of China (English)

    WU Xinxin; ONUKI Kaoru

    2005-01-01

    A very promising technology to achieve a carbon free energy system is to produce hydrogen from water, rather than from fossil fuels. Iodine-sulfur (IS) thermochemical water decomposition is one promising process. The IS process can be used to efficiently produce hydrogen using the high temperature gas-cooled reactor (HTGR) as the energy source supplying gas at 1000℃. This paper describes that demonstration experiment for hydrogen production was carried out by an IS process at a laboratory scale. The results confirmed the feasibility of the closed-loop operation for recycling all the reactants besides the water, H2, and O2. Then the membrane technology was developed to enhance the decomposition efficiency. The maximum attainable one-pass conversion rate of HI exceeds 90% by membrane technology, whereas the equilibrium rate is about 20%.

  9. OVERVIEW OF MODULAR HTGR SAFETY CHARACTERIZATION AND POSTULATED ACCIDENT BEHAVIOR LICENSING STRATEGY

    Energy Technology Data Exchange (ETDEWEB)

    Ball, Sydney J [ORNL

    2014-06-01

    This report provides an update on modular high-temperature gas-cooled reactor (HTGR) accident analyses and risk assessments. One objective of this report is to improve the characterization of the safety case to better meet current regulatory practice, which is commonly geared to address features of today s light water reactors (LWRs). The approach makes use of surrogates for accident prevention and mitigation to make comparisons with LWRs. The safety related design features of modular HTGRs are described, along with the means for rigorously characterizing accident selection and progression methodologies. Approaches commonly used in the United States and elsewhere are described, along with detailed descriptions and comments on design basis (and beyond) postulated accident sequences.

  10. LABORATORY-SCALE PRODUCTION OF ADU GELS BY EXTERNAL GELATION FOR AN INTERMEDIATE HTGR NUCLEAR

    Directory of Open Access Journals (Sweden)

    S Simbolon

    2015-03-01

    Full Text Available LABORATORY-SCALE PRODUCTION OF ADU GELS BY EXTERNAL GELATION FOR AN INTERMEDIATE HTGR NUCLEAR. The The aim of this research is to produce thousands of microsphere ADU (Ammonium Diuranate gels by using external gelation for an intermediate HTGR (High Temperature Gas-cooled Reactor nuclear fuel in laboratory-scale. Microsphere ADU gels were based on sol-solution which was made from a homogeneous mixture of ADUN (Acid Deficient Uranyl Nitrate which was containing uranyl ion in high concentration, a water soluble organic compound PVA (Polyvinyl Alcohol and THFA (Tetrahydrofurfuryl Alcohol. The simple unified home made laboratory experimental machine was developed to replace test tube experiment method which was once used due to a tiny amount of microsphere ADU gels produced. It consists of four main parts: tank filled sol-solution connecting to peristaltic pump and vibrating nozzle, preliminary gelation and gelation column. The machine has successfully converted 150 mL sol-solution into thousands of drops which produced 120 - 130 drops in each minute in steady state in ammonia gas free sector. Preliminary gelation reaction was carried out in ammonia gas sector where drops react with ammonia gas in a bat an eye followed by gelation reaction in column containing ammonia solution 7 M. In ageing process, ADU gels were collected and submerged into a vessel containing ammonia solution which was shaken for 1 hour in a shaker device. Isopropyl alcohol (90% solution was used to wash ADU gels and a digital camera was used to measured spherical form of ADU gels. Diameters in spherical spheroid form were found between 1.8 mm until 2.2 mm. The spherical purity of ADU gels were 10% - 20% others were oblate, prolate spheroid and microsphere which have hugetiny of dimples on the surface.   PRODUKSI GEL ADU SKALA LABORATORIUM DENGAN MENGGUNAKAN GELASI EKSTERNAL UNTUK BAHAN BAKAR ANTARA HTGR. Penelitian ini bertujuan untuk membuat ribuan gel bulat ADU (Ammonium

  11. CFD simulations of separate effects in an HTGR lower plenum under air ingress condition

    Energy Technology Data Exchange (ETDEWEB)

    Gregor, Karel, E-mail: karel.gregor@fs.cvut.cz [Czech Technical University in Prague, Technicka 4, 160 00, Praha 6 (Czech Republic); Dostal, Vaclav [Czech Technical University in Prague, Technicka 4, 160 00, Praha 6 (Czech Republic)

    2012-10-15

    The local heat transfer in an HTGR lower plenum is investigated at the Czech Technical University (CTU) in Prague with collaboration with the U.S. Nuclear Regulatory Commission (NRC). NRC has initiated efforts to build a technical infrastructure necessary to support licensing activities for HTGR's. These efforts include the development and evaluation of computational fluid dynamics (CFD) tools to analyze the system during various conditions. In this case air ingress condition is investigated. The local heat transfer under air ingress condition is strongly affected by the physical phenomena such as molecular diffusion and natural circulation. These separate effects are not yet well understood. Therefore, in the first phase of research it is necessary to perform separate-effects simulations. The CFD solver is exercised and the results are compared with experimental data. The separate-effect benchmarking of the CFD code includes simulations of two separate phases of the JAERI experiments: isothermal molecular diffusion of a binary gas mixture and non-isothermal diffusion and natural circulation of a binary gas mixture. Computational model of experimental apparatus consists of a vertical inverted U-tube connected at the bottom to a cylindrical tank. Commercial CFD solver Fluent 6.3 was used for the simulations. The influence of the size of computational mesh and length of time step of unsteady solver was studied. For the simulation of isothermal molecular diffusion the coarser mesh with about 9000 hexahedral cells was suitable. The length of time step about 0.05 s seems to be optimal. The non-isothermal diffusion and natural circulation simulations were made and compared with experimental data. The onset time of the natural circulation was simulated in good agreement with experiment with small deviation of 2.3%.

  12. Comparison of Material Behavior of Matrix Graphite for HTGR Fuel Elements upon Irradiation: A literature Survey

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young-Woo; Yeo, Seunghwan; Cho, Moon Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The fuel elements for the HTGRs (i.e., spherical fuel element in pebble-bed type core design and fuel compact in prismatic core design) consists of coated fuel particles dispersed and bonded in a closely packed array within a carbonaceous matrix. This matrix is generally made by mixing fully graphitized natural and needle- or pitchcoke originated powders admixed with a binder material (pitch or phenolic resin), The resulting resinated graphite powder mixture, when compacted, may influence a number of material properties as well as its behavior under neutron irradiation during reactor operation. In the fabrication routes of these two different fuel element forms, different consolidation methods are employed; a quasi-isostatic pressing method is generally adopted to make pebbles while fuel compacts are fabricated by uni-axial pressing mode. The result showed that the hardness values obtained from the two directions showed an anisotropic behavior: The values obtained from the perpendicular section showed much higher micro hardness (176.6±10.5MPa in average) than from the parallel section ((125.6±MPa in average). This anisotropic behavior was concluded to be related to the microstructure of the matrix graphite. This may imply that the uni-axial pressing method to make compacts influence the microstructure of the matrix and hence the material properties of the matrix graphite.

  13. R and D status and requirements for PIE in the fields of the HTGR fuel and the innovative basic research on High-Temperature Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Sawa, Kazuhiro; Tobita, Tsutomu; Sumita, Junya [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Ishihara, Masahiro; Hayashi, Kimio; Hoshiya, Taiji; Sekino, Hajime; Ooeda, Etsurou

    1999-09-01

    The High Temperature Engineering Test Reactor (HTTR), which is the first high temperature gas-cooled reactor (HTGR) in Japan, achieved its first criticality in November 1998 at the Oarai Research Establishment of the Japan Atomic Energy Research Institute (JAERI). In the field of HTGR fuel development, JAERI will proceed research and development (R and D) works by the following steps: (STEP-1) confirmation of irradiation performance of the first-loading fuel of the HTTR, (STEP-2) study on irradiation performance of high burnup SiC-coated fuel particle and (STEP-3) development of ZrC-coated fuel particle. Requirements for post-irradiation examination (PIE) are different for each R and D step. In STEP-1, firstly, hot cells will be prepared in the HTTR reactor building to handle spent fuels. In parallel, general equipments such as those for deconsolidation of fuel compacts and for handling coated fuel particles will be installed in the Hot Laboratory at Oarai. In STEP-2, precise PIE techniques, for example, Raman spectroscopy for measurement of stress on irradiated SiC layer, will be investigated. In STEP-3, new PIE techniques should be developed to investigate irradiation behavior of ZrC-coated particle. In the field of the innovative basic research on high-temperature engineering, some preliminary tests have been made on the research areas of (1) new materials development, (2) fusion technology, (3) radiation chemistry and (4) high-temperature in-core instrumentation. Requirements for PIE are under investigation, in particular in the field of the new materials development. Besides more general apparatuses including transmission electron microscopy (TEM), some special apparatuses such as an electron spin resonance (ESR) spectrometer, a specific resistance/Hall coefficient measuring system and a differential scanning calorimeter (DSC) are planned to install in the Hot Laboratory at Oarai. Acquisition of advanced knowledge on the irradiation behavior is expected in

  14. Preliminary plan for the qualification of the LEU/Th fuel cycle for the Fort St. Vrain HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Gulden, T.D.; Gainey, B.W.; Altschwager, C.J. (comps.)

    1980-03-01

    This plan was prepared to ensure that low-enriched uranium/thorium (LEU/Th) would be available as a backup to the highly enriched uranium/thorium (HEU/Th) fuel cycle currently being used in the Fort St. Vrain (FSV) high-temperature gas-cooled reactor (HTGR) in the event that the US nonproliferation policies require it. It describes the program that would be required to develop, qualify, and introduce an LEU/Th fuel cycle into the FSV HTGR on the earliest possible and most optimistic schedule. The results of the study indicate that licensing of the LEU/Th fuel cycle for FSV could be completed and fuel manufacturing could begin about 4.5 years from inception of the program.

  15. Improvement of Modeling HTGR Neutron Physics by Uncertainty Analysis with the Use of Cross-Section Covariance Information

    Science.gov (United States)

    Boyarinov, V. F.; Grol, A. V.; Fomichenko, P. A.; Ternovykh, M. Yu

    2017-01-01

    This work is aimed at improvement of HTGR neutron physics design calculations by application of uncertainty analysis with the use of cross-section covariance information. Methodology and codes for preparation of multigroup libraries of covariance information for individual isotopes from the basic 44-group library of SCALE-6 code system were developed. A 69-group library of covariance information in a special format for main isotopes and elements typical for high temperature gas cooled reactors (HTGR) was generated. This library can be used for estimation of uncertainties, associated with nuclear data, in analysis of HTGR neutron physics with design codes. As an example, calculations of one-group cross-section uncertainties for fission and capture reactions for main isotopes of the MHTGR-350 benchmark, as well as uncertainties of the multiplication factor (k∞) for the MHTGR-350 fuel compact cell model and fuel block model were performed. These uncertainties were estimated by the developed technology with the use of WIMS-D code and modules of SCALE-6 code system, namely, by TSUNAMI, KENO-VI and SAMS. Eight most important reactions on isotopes for MHTGR-350 benchmark were identified, namely: 10B(capt), 238U(n,γ), ν5, 235U(n,γ), 238U(el), natC(el), 235U(fiss)-235U(n,γ), 235U(fiss).

  16. Granulation of core particles suitable for film coating by agitation fluidized bed III. Effect of scale, agitator rotational speed and blade shape on granule properties and development of a high accuracy scale-up theory.

    Science.gov (United States)

    Hamashita, Tomohiro; Ono, Tetsuo; Ono, Masaki; Tsunenari, Yoshinobu; Aketo, Takao; Watano, Satoru

    2009-04-01

    The preparation of core particles suitable for subsequent film coating was examined using different scales of agitation fluidized beds. Specifically, the effects of agitator rotational speed and agitator blade shape in different scales of granulators on granule properties such as mass median diameter, apparent density, friability and shape factor were studied. As the agitator rotational speed was increased or when the agitator blade height and angle were large, the mass median diameter and friability of the granules decreased, while the apparent density and shape factor increased, in a manner independent of the vessel size because the granules were subjected to greater compression, shearing and rolling effects. The same core particles could not be prepared using granulators with different vessel sizes by simply adopting a conventional scale-up theory(1,2)) based on kinetic energy similarity. Here, a novel scale-up theory that takes into account agitator blade shape factors is proposed.(3)) When the two scale-up theories were compared, our new theory was capable of predicting the granule properties more accurately than the conventional theory. By adopting this novel theory, the same core particles could be prepared under different operating conditions in any scale of granulator.

  17. Study of SiC Layer with Fine Grains in HTGR Coated Fuel Particles%HTGR 包覆燃料颗粒碳化硅层细晶化研究

    Institute of Scientific and Technical Information of China (English)

    刘荣正; 刘马林; 刘兵; 邵友林

    2015-01-01

    高温气冷堆(HTGR)是能适应未来能源市场的第四代先进核反应堆堆型之一,其固有安全性的第一道保障是使用的T RISO型包覆燃料颗粒。在T RISO型燃料颗粒4层包覆结构中,SiC包覆层是承受包覆燃料颗粒内压和阻挡裂变产物释放的关键层,制备高质量S iC包覆层是核燃料领域中的重大问题和关键技术之一。本文介绍高温气冷堆燃料颗粒的基本结构,详述制备S iC包覆层的流化床‐化学气相沉积过程,提出S iC层细晶化这一研究方向,并系统阐述包覆燃料颗粒S iC包覆层细晶化的优势。在细晶化S iC材料制备方法方面,系统分析S iC粉体、陶瓷、薄膜和厚膜材料的研究现状,并结合本实验室前期研究成果提出制备细晶S iC包覆层的可行制备策略。%High temperature gas‐cooled reactor (HTGR) with inherent safety character‐istics is considered as one of the attractive and competitive generation Ⅳ nuclear reactors in the future energy markets .Tristructural‐isotropic (TRISO)‐coated particle fuel is the most significant safety aspect in this nuclear reactor ,since it relies on the properties of the four coating layers surrounding the kernel fuel to hinder the release of harmful radio‐active material .Among these layers ,the silicon carbide (SiC) coating is considered the most important as it not only provides the TRISO particle with structural integrity but also retains fission products at elevated temperatures .The preparation of high quality SiC layers is one of significant issues and key technologies in nuclear fuel fabrication . T he basic structure of the T RISO‐coated fuel particles and the fluidized bed chemical vapor deposition (FBCVD) method to prepare SiC layers were introduced .The advanta‐ges of decreasing grain size of SiC layers were analyzed and the idea to prepare SiC layers with fine grain size was proposed .In the preparation strategies ,recent

  18. ICP-MS measurement of iodine diffusion in IG-110 graphite for HTGR/VHTR

    Science.gov (United States)

    Carter, L. M.; Brockman, J. D.; Robertson, J. D.; Loyalka, S. K.

    2016-05-01

    Graphite functions as a structural material and as a barrier to fission product release in HTGR/VHTR designs, and elucidation of transport parameters for fission products in reactor-grade graphite is thus required for reactor source terms calculations. We measured iodine diffusion in spheres of IG-110 graphite using a release method based on Fickain diffusion kinetics. Two sources of iodine were loaded into the graphite spheres; molecular iodine (I2) and cesium iodide (CsI). Measurements of the diffusion coefficient were made over a temperature range of 873-1293 K. We have obtained the following Arrhenius expressions for iodine diffusion:DI , CsI infused =(6 ×10-12 2/s) exp(30,000 J/mol RT) And,DI , I2 infused =(4 ×10-10 m2/s) exp(-11,000 J/mol RT ) The results indicate that iodine diffusion in IG-110 graphite is not well-described by Fickan diffusion kinetics. To our knowledge, these are the first measurements of iodine diffusion in IG-110 graphite.

  19. Thermophoretic and turbulent deposition of graphite dust in HTGR steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Wei, E-mail: pengwei@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China); Zhang, Tianqi; Sun, Xiaokai [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China); Yu, Suyuan, E-mail: suyuan@tsinghua.edu.cn [Center for Combustion Energy, The Key Laboratory for Thermal Science and Power Engineering, Ministry of Education, Tsinghua University, Beijing 100084 (China)

    2016-04-15

    Graphical abstract: Most of small graphite dust particles are deposited in steam generators at low reactor power levels, mostly small and large particles are deposited with few medium-size particles at high reactor power levels. - Highlights: • Thermophoretic deposition is the main mechanism for small particles. • Turbulent deposition is dominant for large particles. • Mostly small particles were deposited at low reactor power. • Both small and large particles are deposited at high reactor power. - Abstract: The present study calculated the graphite dust deposition in the steam generator of HTGR by using a thermophoretic deposition model and a turbulent deposition model based on the temperature and flow field distributions calculated by a computational fluid dynamics (CFD) model. The results showed that the heat flux along the heat transfer surface was not evenly distributed which affect the particle deposition. Thermophoretic deposition is the main factor causing small graphite dust particles to deposit on the surface while turbulent deposition plays the dominant role for large particle deposition. The results also indicate that the deposited particles are mainly small graphite dust particles in steam generator when the reactor is running at low power, with both small and large graphite dust particles at high reactor power levels with fewer medium size particles.

  20. Experiments on the dryout behavior of stratified debris beds

    Energy Technology Data Exchange (ETDEWEB)

    Leininger, Simon; Kulenovic, Rudi; Laurien, Eckart [Stuttgart Univ. (Germany). Inst. of Nuclear Technology and Energy Systems (IKE)

    2015-10-15

    In case of a severe accident with loss of coolant and core meltdown a particle bed (debris) can be formed. The removal of decay heat from the debris bed is of prime importance for the bed's long-term coolability to guarantee the integrity of the RPV. In contrast to previous experiments, the focus is on stratified beds. The experiments have pointed out that the bed's coolability is significantly affected.

  1. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORES 5, 6, 7, & 8: COLUMNAR HEXAGONAL POINT-ON-POINT PACKING WITH A 1:2 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess

    2013-03-01

    PROTEUS is a zero-power research reactor based on a cylindrical graphite annulus with a central cylindrical cavity. The graphite annulus remains basically the same for all experimental programs, but the contents of the central cavity are changed according to the type of reactor being investigated. Through most of its service history, PROTEUS has represented light-water reactors, but from 1992 to 1996 PROTEUS was configured as a pebble-bed reactor (PBR) critical facility and designated as HTR-PROTEUS. The nomenclature was used to indicate that this series consisted of High Temperature Reactor experiments performed in the PROTEUS assembly. During this period, seventeen critical configurations were assembled and various reactor physics experiments were conducted. These experiments included measurements of criticality, differential and integral control rod and safety rod worths, kinetics, reaction rates, water ingress effects, and small sample reactivity effects (Ref. 3). HTR-PROTEUS was constructed, and the experimental program was conducted, for the purpose of providing experimental benchmark data for assessment of reactor physics computer codes. Considerable effort was devoted to benchmark calculations as a part of the HTR-PROTEUS program. References 1 and 2 provide detailed data for use in constructing models for codes to be assessed. Reference 3 is a comprehensive summary of the HTR-PROTEUS experiments and the associated benchmark program. This document draws freely from these references. Only Cores 9 and 10 are evaluated in this benchmark report due to similarities in their construction. The other core configurations of the HTR-PROTEUS program are evaluated in their respective reports as outlined in Section 1.0. Cores 9 and 10 were evaluated and determined to be acceptable benchmark experiments.

  2. HTR-Proteus Pebble Bed Experimental Program Cores 5,6,7,&8: Columnar Hexagonal Point-on-Point Packing with a 1:2 Moderator-to-Fuel Pebble Ratio

    Energy Technology Data Exchange (ETDEWEB)

    Bess, John D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sterbentz, James W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Snoj, Luka [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lengar, Igor [Idaho National Lab. (INL), Idaho Falls, ID (United States); Koberl, Oliver [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    PROTEUS is a zero-power research reactor based on a cylindrical graphite annulus with a central cylindrical cavity. The graphite annulus remains basically the same for all experimental programs, but the contents of the central cavity are changed according to the type of reactor being investigated. Through most of its service history, PROTEUS has represented light-water reactors, but from 1992 to 1996 PROTEUS was configured as a pebble-bed reactor (PBR) critical facility and designated as HTR-PROTEUS. The nomenclature was used to indicate that this series consisted of High Temperature Reactor experiments performed in the PROTEUS assembly. During this period, seventeen critical configurations were assembled and various reactor physics experiments were conducted. These experiments included measurements of criticality, differential and integral control rod and safety rod worths, kinetics, reaction rates, water ingress effects, and small sample reactivity effects (Ref. 3). HTR-PROTEUS was constructed, and the experimental program was conducted, for the purpose of providing experimental benchmark data for assessment of reactor physics computer codes. Considerable effort was devoted to benchmark calculations as a part of the HTR-PROTEUS program. References 1 and 2 provide detailed data for use in constructing models for codes to be assessed. Reference 3 is a comprehensive summary of the HTR-PROTEUS experiments and the associated benchmark program. This document draws freely from these references. Only Cores 9 and 10 are evaluated in this benchmark report due to similarities in their construction. The other core configurations of the HTR-PROTEUS program are evaluated in their respective reports as outlined in Section 1.0. Cores 9 and 10 were evaluated and determined to be acceptable benchmark experiments.

  3. Irradiated-Microsphere Gamma Analyzer (IMGA): an integrated system for HTGR coated particle fuel performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Kania, M.J.; Valentine, K.H.

    1980-02-01

    The Irradiated-Microsphere Gamma Analyzer (IMGA) System, designed and built at ORNL, provides the capability of making statistically accurate failure fraction measurements on irradiated HTGR coated particle fuel. The IMGA records the gamma-ray energy spectra from fuel particles and performs quantitative analyses on these spectra; then, using chemical and physical properties of the gamma emitters it makes a failed-nonfailed decision concerning the ability of the coatings to retain fission products. Actual retention characteristics for the coatings are determined by measuring activity ratios for certain gamma emitters such as /sup 137/Cs//sup 95/Zr and /sup 144/Ce//sup 95/Zr for metallic fission product retention and /sup 134/Cs//sup 137/Cs for an indirect measure of gaseous fission product retention. Data from IMGA (which can be put in the form of n failures observed in N examinations) can be accurately described by the binomial probability distribution model. Using this model, a mathematical relationship between IMGA data (n,N), failure fraction, and confidence level was developed. To determine failure fractions of less than or equal to 1% at confidence levels near 95%, this model dictates that from several hundred to several thousand particles must be examined. The automated particle handler of the IMGA system provides this capability. As a demonstration of failure fraction determination, fuel rod C-3-1 from the OF-2 irradiation capsule was analyzed and failure fraction statistics were applied. Results showed that at the 1% failure fraction level, with a 95% confidence level, the fissile particle batch could not meet requirements; however, the fertile particle exceeded these requirements for the given irradiation temperature and burnup.

  4. 3D Nondestructive Visualization and Evaluation of TRISO Particles Distribution in HTGR Fuel Pebbles Using Cone-Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Gongyi Yu

    2017-01-01

    Full Text Available A nonuniform distribution of tristructural isotropic (TRISO particles within a high-temperature gas-cooled reactor (HTGR pebble may lead to excessive thermal gradients and nonuniform thermal expansion during operation. If the particles are closely clustered, local hotspots may form, leading to excessive stresses on particle layers and an increased probability of particle failure. Although X-ray digital radiography (DR is currently used to evaluate the TRISO distributions in pebbles, X-ray DR projection images are two-dimensional in nature, which would potentially miss some details for 3D evaluation. This paper proposes a method of 3D visualization and evaluation of the TRISO distribution in HTGR pebbles using cone-beam computed tomography (CBCT: first, a pebble is scanned on our high-resolution CBCT, and 2D cross-sectional images are reconstructed; secondly, all cross-sectional images are restructured to form the 3D model of the pebble; then, volume rendering is applied to segment and display the TRISO particles in 3D for visualization and distribution evaluation. For method validation, several pebbles were scanned and the 3D distributions of the TRISO particles within the pebbles were produced. Experiment results show that the proposed method provides more 3D than DR, which will facilitate pebble fabrication research and production quality control.

  5. Bed rest during pregnancy

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000581.htm Bed rest during pregnancy To use the sharing features on ... few days or weeks. This is called bed rest. Bed rest used to be recommended routinely for ...

  6. Simulated fission product-SiC interaction in Triso-coated LEU or MEU HTGR fuel particles

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, R.L.; Lindemer, T.B.; Beahm, E.C.

    1980-11-01

    Proliferation issues relating to the use of highly enriched uranium (HEU) have led to an evaluation of the fission product-SiC interaction problems that might arise if low enriched uranium (LEU) or medium enriched uranium (MEU) were used as fissile fuel in HTGR systems. Simulated Triso-coated UO/sub 2/, UC/sub 2/, and UO/sub 2//UC/sub 2/ particles mixed with varying amounts of Mo, Ru, Rh, Pd, Ag, and Cd were prepared. These fission products were chosen because, after full burnup, their concentrations are higher in LEU and MEU fuels than in HEU fuel. After the particles were heat treated in the laboratory, their behavior was examined by use of metallography, scanning electron microscopy, and electron microprobe x-ray analysis.

  7. Assesment of advanced step models for steady state Monte Carlo burnup calculations in application to prismatic HTGR

    Directory of Open Access Journals (Sweden)

    Kępisty Grzegorz

    2015-09-01

    Full Text Available In this paper, we compare the methodology of different time-step models in the context of Monte Carlo burnup calculations for nuclear reactors. We discuss the differences between staircase step model, slope model, bridge scheme and stochastic implicit Euler method proposed in literature. We focus on the spatial stability of depletion procedure and put additional emphasis on the problem of normalization of neutron source strength. Considered methodology has been implemented in our continuous energy Monte Carlo burnup code (MCB5. The burnup simulations have been performed using the simplified high temperature gas-cooled reactor (HTGR system with and without modeling of control rod withdrawal. Useful conclusions have been formulated on the basis of results.

  8. Effect of a flow-corrective insert on the flow pattern in a pebble bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yu; Gui, Nan; Yang, Xingtuan [Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084 (China); Tu, Jiyuan [Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084 (China); School of Aerospace, Mechanical & Manufacturing Engineering, RMIT University, Melbourne 3083, VIC (Australia); Jiang, Shengyao, E-mail: shengyaojiang@sina.com [Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084 (China)

    2016-04-15

    Highlights: • Effect of an insert on improving flow uniformity and eliminating stagnant zone is studied. • Three values concerned with the stagnant zone, radial uniformity and flow sequence are used. • Outlet diameter is a critical parameter that determines balancing mechanism of the insert. • Height/location is varied to let the insert work in unbalanced region and avoid adverse effect. - Abstract: A flow-corrective insert is adopted in the pebble-bed high temperature gas-cooled reactor (HTGR) to improve flow performance of the pebble flow for the first time. 3D discrete element method (DEM) modeling is employed to study this slow and dense granular flow. It is verified that locating a properly designed insert in the bed can help transform unsatisfactory flow field to the preferred flow pattern for pebble bed reactors. Three characteristic values on the stagnant zone, radial uniformity and flow sequence of pebble flow are defined to evaluate uniformity of the overall flow field quantitatively. The results demonstrate that the pebble bed equipped with an insert performs better than normal beds from all these three aspects. Moreover, based on numerical experiments, several universal tips for insert design on height, location and outlet diameter are suggested.

  9. HTGR Generic Technology Program: safety, systems and component design and development. Quarterly progress report for the period ending March 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1978-04-01

    The work documented includes HTGR safety and safety-related studies to better understand and more accurately define safety characteristics and safety margins of GCRs under postulated accident conditions. Also included are the design, analysis, and testing of th PCRV, liner, penetrations, thermal barrier, reactor internals, steam generator, CAHE, and rotating machinery. Design studies and analysis plus experimental procedures and results are discussed and, where appropriate, the data are presented in tables, graphs, and photographs.

  10. Apparatus for controlling molten core debris. [LMFBR

    Science.gov (United States)

    Golden, M.P.; Tilbrook, R.W.; Heylmun, N.F.

    1977-07-19

    Disclosed is an apparatus for containing, cooling, diluting, dispersing and maintaining subcritical the molten core debris assumed to melt through the bottom of a nuclear reactor pressure vessel in the unlikely event of a core meltdown. The apparatus is basically a sacrificial bed system which includes an inverted conical funnel, a core debris receptacle including a spherical dome, a spherically layered bed of primarily magnesia bricks, a cooling system of zig-zag piping in graphite blocks about and below the bed and a cylindrical liner surrounding the graphite blocks including a steel shell surrounded by firebrick. Tantalum absorber rods are used in the receptacle and bed. 9 claims, 22 figures.

  11. Deleterious Thermal Effects Due To Randomized Flow Paths in Pebble Bed, and Particle Bed Style Reactors

    Science.gov (United States)

    Moran, Robert P.

    2013-01-01

    A review of literature associated with Pebble Bed and Particle Bed reactor core research has revealed a systemic problem inherent to reactor core concepts which utilize randomized rather than structured coolant channel flow paths. For both the Pebble Bed and Particle Bed Reactor designs; case studies reveal that for indeterminate reasons, regions within the core would suffer from excessive heating leading to thermal runaway and localized fuel melting. A thermal Computational Fluid Dynamics model was utilized to verify that In both the Pebble Bed and Particle Bed Reactor concepts randomized coolant channel pathways combined with localized high temperature regions would work together to resist the flow of coolant diverting it away from where it is needed the most to cooler less resistive pathways where it is needed the least. In other words given the choice via randomized coolant pathways the reactor coolant will take the path of least resistance, and hot zones offer the highest resistance. Having identified the relationship between randomized coolant channel pathways and localized fuel melting it is now safe to assume that other reactor concepts that utilize randomized coolant pathways such as the foam core reactor are also susceptible to this phenomenon.

  12. Interactive simulations of gas-turbine modular HTGR transients and heatup accidents

    Energy Technology Data Exchange (ETDEWEB)

    Ball, S.J.; Nypaver, D.J.

    1994-06-01

    An interactive workstation-based simulator has been developed for performing analyses of modular high-temperature gas-cooled reactor (MHTGR) core transients and accidents. It was originally developed at Oak Ridge National Laboratory for the US Nuclear Regulatory Commission to assess the licensability of the US Department of Energy (DOE) steam cycle design 350-MW(t) MHTGR. Subsequently, the code was modified under DOE sponsorship to simulate the 450-MW(t) Gas Turbine (GT) design and to aid in development and design studies. Features of the code (MORECA-GT) include detailed modeling of 3-D core thermal-hydraulics, interactive workstation capabilities that allow user/analyst or ``operator`` involvement in accident scenarios, and options for studying anticipated transients without scram (ATWS) events. In addition to the detailed models for the core, MORECA includes models for the vessel, Shutdown Cooling System (SCS), and Reactor Cavity Cooling System (RCCS), and core point kinetics to accommodate ATWS events. The balance of plant (BOP) is currently not modeled. The interactive workstation features include options for on-line parameter plots and 3-D graphic temperature profiling. The studies to date show that the proposed MHTGR designs are very robust and can generally withstand the consequences of even the extremely low probability postulated accidents with little or no damage to the reactor`s fuel or metallic components.

  13. Investigation on the pebble bed flow model in VSOP

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hao, E-mail: haochen.heu@163.com; Fu, Li, E-mail: lifu@mail.tsinghua.edu.cn

    2014-05-01

    In pebble bed high temperature gas cooled reactor (HTR), the fuel pebbles will pass the reactor core several times, in order to flatten the power distribution, and to unify the discharging burnup. But the VSOP code approximates the pebble bed flow because of current computer capability. In order to simulate the pebble bed flow in HTR more realistically and to validate the approximation in pebble bed flow model in VSOP, a new code based on Monte Carlo method has been developed to analysis the characteristic of the pebble bed flow, particularly the average burnup distribution in the core, discharging burnup, and the number of pebble passes. Statistics analysis shows that several millions of Monte Carlo simulation can provide reasonable result and the VSOP treatment of the pebble bed flow model is reasonable. The Monte Carlo simulation can provide more information for the pebble flow and reactor operation.

  14. High temperature gas-cooled reactor (HTGR) graphite pebble fuel: Review of technologies for reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Mcwilliams, A. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-08

    This report reviews literature on reprocessing high temperature gas-cooled reactor graphite fuel components. A basic review of the various fuel components used in the pebble bed type reactors is provided along with a survey of synthesis methods for the fabrication of the fuel components. Several disposal options are considered for the graphite pebble fuel elements including the storage of intact pebbles, volume reduction by separating the graphite from fuel kernels, and complete processing of the pebbles for waste storage. Existing methods for graphite removal are presented and generally consist of mechanical separation techniques such as crushing and grinding chemical techniques through the use of acid digestion and oxidation. Potential methods for reprocessing the graphite pebbles include improvements to existing methods and novel technologies that have not previously been investigated for nuclear graphite waste applications. The best overall method will be dependent on the desired final waste form and needs to factor in the technical efficiency, political concerns, cost, and implementation.

  15. Bed Bugs - Multiple Languages

    Science.gov (United States)

    ... Are Here: Home → Multiple Languages → All Health Topics → Bed Bugs URL of this page: https://medlineplus.gov/languages/ ... V W XYZ List of All Topics All Bed Bugs - Multiple Languages To use the sharing features on ...

  16. Bed Bugs and Schools

    Science.gov (United States)

    Bed bugs have long been a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. They are successful hitchhikers, and can move from an infested site to furniture, bedding, baggage, boxes, and clothing.

  17. A hybrid HTGR system producing electricity, hydrogen and such other products as water demanded in the Middle East

    Energy Technology Data Exchange (ETDEWEB)

    Yan, X., E-mail: yan.xing@jaea.go.jp; Noguchi, H.; Sato, H.; Tachibana, Y.; Kunitomi, K.; Hino, R.

    2014-05-01

    Alternative energy products are being considered by the Middle East countries for both consumption and export. Electricity, water, and hydrogen produced not from oil and gas are amongst those desirable. A hybrid nuclear production system, GTHTR300C, under development in JAEA can achieve this regional strategic goal. The system is based on a 600 MWt HTGR and equipped to cogenerate electricity by gas turbine and seawater desalination by using only the nuclear plant waste heat. Hydrogen is produced via a thermochemical water-splitting process driven by the reactor's 950 °C heat. Additionally process steam may be produced for industrial uses. An example is shown of manufacturing soda ash, an internationally traded commodity, from using the steam produced and the brine discharged from desalination. The nuclear reactor satisfies nearly all energy requirements for the hybrid generations without emitting CO{sub 2}. The passive safety of the reactor as described in the paper permits proximity of siting the reactor with the production facilities to enhance energy transmission. Production flowsheet of the GTHTR300C is given for up to 300 MWe electricity, 58 t/day hydrogen, 56,000 m{sup 3}/day potable water, 3500 t/day steam, and 1000 t/day soda ash. The production thermal efficiency reaches 88%.

  18. Introduction to Bed Bugs

    Science.gov (United States)

    ... that there are ways to control bed bugs. Getting good, solid information is the first step in both prevention and control. While there is no chemical quick fix, there are effective strategies to control bed bugs involving both non-chemical and chemical methods. Bed bugs can be hard to find and ...

  19. 先进的规则床模块式高温气冷堆概念%Advanced ordered bed modular HTGR reactor concept

    Institute of Scientific and Technical Information of China (English)

    田嘉夫

    2008-01-01

    规则床模块堆是燃料球呈规则堆积的一种先进的模块式高温气冷堆设计.燃料球在平面上成正方形排列,四个球的中心是次一层球的位置,形成正四棱锥堆积.当燃料球落入被做成一定几何形状的堆芯空腔时,就自动形成规则堆积.燃料球可以从反应堆顶部装入和卸出,能够在较短的停堆时间内完成换料操作.规则床堆芯是一种密实体,具有很强的结构适应性和稳定性.在模块化设计中,保持非能动冷却和限制最高燃料温度的条件下,它能够提高输出功率和降低堆芯压降,同时还兼有球形燃料堆和柱状燃料堆的主要优点.本文介绍规则堆积床特性和预测规则床模块堆的设计性能.

  20. Collaborative Strategy on Bed Bugs

    Science.gov (United States)

    The Collaborative Strategy on Bed Bugs was developed by the Federal Bed Bug Workgroup to clarify the federal role in bed bug control and highlight ways that government, community, academia and private industry can work together on bed bug issues.

  1. Summary of Planned Implementation for the HTGR Lessons Learned Applicable to the NGNP

    Energy Technology Data Exchange (ETDEWEB)

    Ian Mckirdy

    2011-09-01

    This document presents a reconciliation of the lessons learned during a 2010 comprehensive evaluation of pertinent lessons learned from past and present high temperature gas-cooled reactors that apply to the Next Generation Nuclear Plant Project along with current and planned activities. The data used are from the latest Idaho National Laboratory research and development plans, the conceptual design report from General Atomics, and the pebble bed reactor technology readiness study from AREVA. Only those lessons related to the structures, systems, and components of the Next Generation Nuclear Plant (NGNP), as documented in the recently updated lessons learned report are addressed. These reconciliations are ordered according to plant area, followed by the affected system, subsystem, or component; lesson learned; and finally an NGNP implementation statement. This report (1) provides cross references to the original lessons learned document, (2) describes the lesson learned, (3) provides the current NGNP implementation status with design data needs associated with the lesson learned, (4) identifies the research and development being performed related to the lesson learned, and (5) summarizes with a status of how the lesson learned has been addressed by the NGNP Project.

  2. Progress report on evaluation of potential impact of /sup 14/C releases from an HTGR reprocessing facility

    Energy Technology Data Exchange (ETDEWEB)

    Killough, G.G.; Dixon, K.R.; Edwards, N.T.; Murphy, B.D.; Rohwer, P.S.; Harris, W.F.; Kaye, S.V.

    1976-07-01

    The potential radiological impacts of atmospheric releases of /sup 14/CO/sub 2/ are assessed for a model HTGR reprocessing facility. Two off-gas systems were considered: (1) a 300-ft stack with no thermal output, and (2) a 1000-ft stack with a stack gas temperature of 80/sup 0/C and heat output of 4.2 x 10/sup 7/ Btu/hr. Meteorological data for the Oak Ridge area were used with an assumed annual release rate of 5000 Ci as input to an atmospheric transport model, which in turn was used to predict air concentrations of /sup 14/C at points of habitation and food production in the local area (within 50 miles) of the facility. The total-body dose rates estimated for the average resident living in the local area were 0.107 mrem/yr for the 300-ft stack and 0.063 mrem/yr for the 1000-ft stack. Population doses were computed for a population of 10/sup 6/ individuals uniformly distributed within the 50-mile local area of the facility; these were 110 man-rem for the 300-ft stack and 63 man-rem for the 1000-ft stack. The results of these dose calculations suggest that a 1000-ft stack would be very effective in reducing the estimated doses. Plant growth carbon assimilation model was derived in order to investigate the adequacy of the assumption of tissue equilibration with time-averaged ambient specific activity as a basis for dose estimates. Simulation runs with these models suggest that in the presence of frequent fluctuations of large amplitude in the ambient air /sup 14/CO/sub 2/ concentrations, specific activity in plant tissue can exceed conventionally calculated time-averaged specific activity.

  3. Conceptual study of advanced PWR core design. Development of advanced PWR core neutronics analysis system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Hyo; Kim, Seung Cho; Kim, Taek Kyum; Cho, Jin Young; Lee, Hyun Cheol; Lee, Jung Hun; Jung, Gu Young [Seoul National University, Seoul (Korea, Republic of)

    1995-08-01

    The neutronics design system of the advanced PWR consists of (i) hexagonal cell and fuel assembly code for generation of homogenized few-group cross sections and (ii) global core neutronics analysis code for computations of steady-state pin-wise or assembly-wise core power distribution, core reactivity with fuel burnup, control rod worth and reactivity coefficients, transient core power, etc.. The major research target of the first year is to establish the numerical method and solution of multi-group diffusion equations for neutronics code development. Specifically, the following studies are planned; (i) Formulation of various numerical methods such as finite element method(FEM), analytical nodal method(ANM), analytic function expansion nodal(AFEN) method, polynomial expansion nodal(PEN) method that can be applicable for the hexagonal core geometry. (ii) Comparative evaluation of the numerical effectiveness of these methods based on numerical solutions to various hexagonal core neutronics benchmark problems. Results are follows: (i) Formulation of numerical solutions to multi-group diffusion equations based on numerical methods. (ii) Numerical computations by above methods for the hexagonal neutronics benchmark problems such as -VVER-1000 Problem Without Reflector -VVER-440 Problem I With Reflector -Modified IAEA PWR Problem Without Reflector -Modified IAEA PWR Problem With Reflector -ANL Large Heavy Water Reactor Problem -Small HTGR Problem -VVER-440 Problem II With Reactor (iii) Comparative evaluation on the numerical effectiveness of various numerical methods. (iv) Development of HEXFEM code, a multi-dimensional hexagonal core neutronics analysis code based on FEM. In the target year of this research, the spatial neutronics analysis code for hexagonal core geometry(called NEMSNAP-H temporarily) will be completed. Combination of NEMSNAP-H with hexagonal cell and assembly code will then equip us with hexagonal core neutronics design system. (Abstract Truncated)

  4. Gas-cooled reactor programs: High-Temperature Gas-Cooled Reactor Base-Technology Program. Annual progress report for period ending December 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1980-07-01

    Progress in HTGR studies is reported in the following areas: HTGR chemistry; fueled graphite development; prestressed concrete pressure vessel development; structural materials; HTGR graphite studies; and evaluation of the pebble-bed HTR.

  5. Closed Brayton Cycle power system with a high temperature pellet bed reactor heat source for NEP applications

    Science.gov (United States)

    Juhasz, Albert J.; El-Genk, Mohamed S.; Harper, William B., Jr.

    1992-01-01

    Capitalizing on past and future development of high temperature gas reactor (HTGR) technology, a low mass 15 MWe closed gas turbine cycle power system using a pellet bed reactor heating helium working fluid is proposed for Nuclear Electric Propulsion (NEP) applications. Although the design of this directly coupled system architecture, comprising the reactor/power system/space radiator subsystems, is presented in conceptual form, sufficient detail is included to permit an assessment of overall system performance and mass. Furthermore, an attempt is made to show how tailoring of the main subsystem design characteristics can be utilized to achieve synergistic system level advantages that can lead to improved reliability and enhanced system life while reducing the number of parasitic load driven peripheral subsystems.

  6. Distribution of fission products in Peach Bottom HTGR fuel element E11-07

    Energy Technology Data Exchange (ETDEWEB)

    Wichner, R.P.; Dyer, F.F.; Martin, W.J.; Bate, L.C.

    1977-04-01

    This is the second in a projected series of six post-irradiation examinations of Peach Bottom High-Temperature Gas-Cooled Reactor driver fuel elements. Element E11-07, the subject of this report, received an equivalent of 701 full-power days of irradiation prior to scheduled withdrawal. The examination procedures emphasized the determination of fission product distributions in the graphite portions of the fuel element. Continuous axial scans indicated a /sup 137/Cs inventory of 17 Ci in the graphite sleeve and 8.3 Ci in the spine at the time of element withdrawal from the core. In addition, the nuclides /sup 134/Cs, /sup 110m/Ag, /sup 60/Co, and /sup 154/Eu were found in the graphite portions of the fuel element in significant amounts. Radial distributions of these nuclides plus the distribution of the beta emitters /sup 3/H, /sup 14/C, and /sup 90/Sr were obtained at six axial locations, four within the fueled region and one each above and below. The radial dissection was accomplished by use of a manipulator-operated lathe in a hot cell. These profiles reveal an increased degree of penetration of /sup 134/Cs, relative to /sup 137/Cs, evidently due to a longer time spent as xenon precursor. In addition to fission product distribution, the appearance of the element components was recorded photographically, fuel compact and graphite dimensions were recorded at numerous locations, and metallographic examinations of the fuel were performed.

  7. STAT, GAPS, STRAIN, DRWDIM: a system of computer codes for analyzing HTGR fuel test element metrology data. User's manual

    Energy Technology Data Exchange (ETDEWEB)

    Saurwein, J.J.

    1977-08-01

    A system of computer codes has been developed to statistically reduce Peach Bottom fuel test element metrology data and to compare the material strains and fuel rod-fuel hole gaps computed from these data with HTGR design code predictions. The codes included in this system are STAT, STRAIN, GAPS, and DRWDIM. STAT statistically evaluates test element metrology data yielding fuel rod, fuel body, and sleeve irradiation-induced strains; fuel rod anisotropy; and additional data characterizing each analyzed fuel element. STRAIN compares test element fuel rod and fuel body irradiation-induced strains computed from metrology data with the corresponding design code predictions. GAPS compares test element fuel rod, fuel hole heat transfer gaps computed from metrology data with the corresponding design code predictions. DRWDIM plots the measured and predicted gaps and strains. Although specifically developed to expedite the analysis of Peach Bottom fuel test elements, this system can be applied, without extensive modification, to the analysis of Fort St. Vrain or other HTGR-type fuel test elements.

  8. THE COMPONENT TEST FACILITY – A NATIONAL USER FACILITY FOR TESTING OF HIGH TEMPERATURE GAS-COOLED REACTOR (HTGR) COMPONENTS AND SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    David S. Duncan; Vondell J. Balls; Stephanie L. Austad

    2008-09-01

    The Next Generation Nuclear Plant (NGNP) and other High-Temperature Gas-cooled Reactor (HTGR) Projects require research, development, design, construction, and operation of a nuclear plant intended for both high-efficiency electricity production and high-temperature industrial applications, including hydrogen production. During the life cycle stages of an HTGR, plant systems, structures and components (SSCs) will be developed to support this reactor technology. To mitigate technical, schedule, and project risk associated with development of these SSCs, a large-scale test facility is required to support design verification and qualification prior to operational implementation. As a full-scale helium test facility, the Component Test facility (CTF) will provide prototype testing and qualification of heat transfer system components (e.g., Intermediate Heat Exchanger, valves, hot gas ducts), reactor internals, and hydrogen generation processing. It will perform confirmation tests for large-scale effects, validate component performance requirements, perform transient effects tests, and provide production demonstration of hydrogen and other high-temperature applications. Sponsored wholly or in part by the U.S. Department of Energy, the CTF will support NGNP and will also act as a National User Facility to support worldwide development of High-Temperature Gas-cooled Reactor technologies.

  9. Fluidized bed calciner apparatus

    Science.gov (United States)

    Owen, Thomas J.; Klem, Jr., Michael J.; Cash, Robert J.

    1988-01-01

    An apparatus for remotely calcining a slurry or solution feed stream of toxic or hazardous material, such as ammonium diurante slurry or uranyl nitrate solution, is disclosed. The calcining apparatus includes a vertical substantially cylindrical inner shell disposed in a vertical substantially cylindrical outer shell, in which inner shell is disposed a fluidized bed comprising the feed stream material to be calcined and spherical beads to aid in heat transfer. Extending through the outer and inner shells is a feed nozzle for delivering feed material or a cleaning chemical to the beads. Disposed in and extending across the lower portion of the inner shell and upstream of the fluidized bed is a support member for supporting the fluidized bed, the support member having uniform slots for directing uniform gas flow to the fluidized bed from a fluidizing gas orifice disposed upstream of the support member. Disposed in the lower portion of the inner shell are a plurality of internal electric resistance heaters for heating the fluidized bed. Disposed circumferentially about the outside length of the inner shell are a plurality of external heaters for heating the inner shell thereby heating the fluidized bed. Further, connected to the internal and external heaters is a means for maintaining the fluidized bed temperature to within plus or minus approximately 25.degree. C. of a predetermined bed temperature. Disposed about the external heaters is the outer shell for providing radiative heat reflection back to the inner shell.

  10. A study of fuel failure behavior in high burnup HTGR fuel. Analysis by STRESS3 and STAPLE codes

    Energy Technology Data Exchange (ETDEWEB)

    Martin, David G.; Sawa, Kazuhiro; Ueta, Shouhei; Sumita, Junya [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    2001-05-01

    In current high temperature gas-cooled reactors (HTGRs), Tri-isotropic coated fuel particles are employed as fuel. In safety design of the HTGR fuels, it is important to retain fission products within particles so that their release to primary coolant does not exceed an acceptable level. From this point of view, the basic design criteria for the fuel are to minimize the failure fraction of as-fabricated fuel coating layers and to prevent significant additional fuel failures during operation. This report attempts to model fuel behavior in irradiation tests using the U.K. codes STRESS3 and STAPLE. Test results in 91F-1A and HRB-22 capsules irradiation tests, which were carried out at the Japan Materials Testing Reactor of JAERI and at the High Flux Isotope Reactor of Oak Ridge National Laboratory, respectively, were employed in the calculation. The maximum burnup and fast neutron fluence were about 10%FIMA and 3 x 10{sup 25} m{sup -2}, respectively. The fuel for the irradiation tests was called high burnup fuel, whose target burnup and fast neutron fluence were higher than those of the first-loading fuel of the High Temperature Engineering Test Reactor. The calculation results demonstrated that if only mean fracture stress values of PyC and SiC are used in the calculation it is not possible to predict any particle failures, by which is meant when all three load bearing layers have failed. By contrast, when statistical variations in the fracture stresses and particle specifications are taken into account, as is done in the STAPLE code, failures can be predicted. In the HRB-22 irradiation test, it was concluded that the first two particles which had failed were defective in some way, but that the third and fourth failures can be accounted for by the pressure vessel model. In the 91F-1A irradiation test, the result showed that 1 or 2 particles had failed towards the end of irradiation in the upper capsule and no particles failed in the lower capsule. (author)

  11. ANALISIS TRANSIEN PADA FIXED BED NUCLEAR REACTOR

    Directory of Open Access Journals (Sweden)

    M. Rizaal

    2015-03-01

    Full Text Available Desain teras Fixed Bed Nuclear Reactor (FBNR yang modular memungkinkan pengendalian daya dapat dilakukan dengan mengatur ketinggian suspended core dan laju aliran massa pendingin. Tujuan penelitian ini adalah mempelajari perubahan daya termal teras sebagai akibat perubahan laju aliran massa pendingin yang masuk ke teras reaktor dan perubahan ketinggian suspended core serta mempelajari karakteristik keselamatan melekat yang dimiliki FBNR saat terjadi kegagalan pelepasan kalor (loss of heat sink. Keadaan neutronik teras dimodelkan pada kondisi tunak dengan menggunakan paket program Standard Reactor Analysis Code (SRAC untuk memperoleh data fluks neutron, konstanta grup, fraksi neutron kasip, konstanta peluruhan prekursor neutron kasip, dan beberapa parameter teras penting lainnya. Selanjutnya data tersebut digunakan pada perhitungan transien sebagai syarat awal. Analisis transien dilakukan pada tiga kondisi, yaitu saat terjadi penurunan laju aliran massa pendingin, saat terjadi penurunan ketinggian suspended core, dan saat terjadi kegagalan sistem pelepasan kalor. Hasil yang diperoleh dari penelitian ini menunjukkan bahwa penurunan laju aliran massa pendingin sebesar 50%, dari kondisi normal, menyebabkan daya termal teras turun 28% dibanding daya sebelumnya. Penurunan ketinggian suspended core sebesar 30% dari ketinggian normal menyebabkan daya termal teras turun 17% dibanding daya sebelumnya. Sementara untuk kondisi kegagalan sistem pelepasan kalor, daya termal teras mengalami penurunan sebesar 76%. Dengan demikian, pengendalian daya pada FBNR dapat dilakukan dengan mengatur laju aliran massa pendingin dan ketinggian suspended core, serta keselamatan melekat yang handal pada kondisi kegagalan sistem pelepasan kalor. Kata kunci: FBNR, transien, daya, laju aliran massa, suspended core Modular in design enables Fixed Bed Nuclear Reactor (FBNR power controlled by the adjustment of suspended core and coolant flow rate. The main purposes of this paper

  12. Tapered bed bioreactor

    Science.gov (United States)

    Scott, Charles D.; Hancher, Charles W.

    1977-01-01

    A vertically oriented conically shaped column is used as a fluidized bed bioreactor wherein biologically catalyzed reactions are conducted in a continuous manner. The column utilizes a packing material a support having attached thereto a biologically active catalytic material.

  13. Bed Bugs FAQs

    Science.gov (United States)

    ... Bed bugs have been found in five-star hotels and resorts and their presence is not determined ... sleep. These areas include apartments, shelters, rooming houses, hotels, cruise ships, buses, trains, and dorm rooms. They ...

  14. Moving-bed sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Ayala, R.E.; Gupta, R.P.; Chuck, T.

    1995-12-01

    The objective of this program is to develop mixed-metal oxide sorbent formulations that are suitable for moving-bed, high-temperature, desulfurization of coal gas. Work continues on zinc titanates formulations and Z-sorb III sorbent.

  15. Bed Bug Information Clearinghouse

    Science.gov (United States)

    Its purpose is to help states, communities, and consumers in efforts to prevent and control bed bug infestations. Currently includes only reviewed material from federal/state/local government agencies, extension services, and universities.

  16. Bed Bug Tips

    Science.gov (United States)

    How to deal with bed bugs in one printable page. Ten tips include ensuring correct insect identification, reducing clutter, understand integrated pest management, using mattress and box spring encasements, and heat treatment.

  17. Proteomics Core

    Data.gov (United States)

    Federal Laboratory Consortium — Proteomics Core is the central resource for mass spectrometry based proteomics within the NHLBI. The Core staff help collaborators design proteomics experiments in a...

  18. Proteomics Core

    Data.gov (United States)

    Federal Laboratory Consortium — Proteomics Core is the central resource for mass spectrometry based proteomics within the NHLBI. The Core staff help collaborators design proteomics experiments in...

  19. MELCOR程序在HTGR事故分析中的最新进展%Latest Progress of HTGR Accident Analysis in MELCOR

    Institute of Scientific and Technical Information of China (English)

    周克峰; 陈召林; 冯进军; 高强; 李茂林; 刘运陶

    2013-01-01

    MELCOR程序是美国NRC在安全评审中使用的一体化系统分析程序,早期主要用于轻水堆严重事故分析.近年来,该程序逐渐用于高温气冷堆的石墨腐蚀、裂变产物行为和石墨粉尘等物理现象方面的研究.本文介绍了在最新版本的MELCOR 2.1程序中,针对高温气冷堆特点所进行的扩展和开发,以及MELCOR程序在高温气冷堆(HTGR)事故分析中的计算流程.

  20. Nuclear Safeguards Considerations For The Pebble Bed Modular Reactor (PBMR)

    Energy Technology Data Exchange (ETDEWEB)

    Phillip Casey Durst; David Beddingfield; Brian Boyer; Robert Bean; Michael Collins; Michael Ehinger; David Hanks; David L. Moses; Lee Refalo

    2009-10-01

    High temperature reactors (HTRs) have been considered since the 1940s, and have been constructed and demonstrated in the United Kingdom (Dragon), United States (Peach Bottom and Fort Saint Vrain), Japan (HTTR), Germany (AVR and THTR-300), and have been the subject of conceptual studies in Russia (VGM). The attraction to these reactors is that they can use a variety of reactor fuels, including abundant thorium, which upon reprocessing of the spent fuel can produce fissile U-233. Hence, they could extend the stocks of available uranium, provided the fuel is reprocessed. Another attractive attribute is that HTRs typically operate at a much higher temperature than conventional light water reactors (LWRs), because of the use of pyrolytic carbon and silicon carbide coated (TRISO) fuel particles embedded in ceramic graphite. Rather than simply discharge most of the unused heat from the working fluid in the power plant to the environment, engineers have been designing reactors for 40 years to recover this heat and make it available for district heating or chemical conversion plants. Demonstrating high-temperature nuclear energy conversion was the purpose behind Fort Saint Vrain in the United States, THTR-300 in Germany, HTTR in Japan, and HTR-10 and HTR-PM, being built in China. This resulted in nuclear reactors at least 30% or more thermodynamically efficient than conventional LWRs, especially if the waste heat can be effectively utilized in chemical processing plants. A modern variant of high temperature reactors is the Pebble Bed Modular Reactor (PBMR). Originally developed in the United States and Germany, it is now being redesigned and marketed by the Republic of South Africa and China. The team examined historical high temperature and high temperature gas reactors (HTR and HTGR) and reviewed safeguards considerations for this reactor. The following is a preliminary report on this topic prepared under the ASA-100 Advanced Safeguards Project in support of the NNSA Next

  1. Kinetics of Reduction Reaction in Micro-Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    LINYin-he; GUOZhan—cheng; TANGHui—qing; REN Shan; LIJing—wei

    2012-01-01

    Micro-fluidized bed reactor is a new research method for the reduction of iron ore fines. The reactor is op- erated as a differential reactor to ensure a constant gas concentration and temperature within the reactor volume. In order to understand the dynamic process of the reduction reaction in micro-fluidized bed, a series of kinetic experi- ments were designed. In the micro fluidized bed, the use of shrinking core model describes the dynamic behavior of reduction of iron ore. And the apparent activation energy is calculated in the range of 700--850 ~C while the initial atmosphere is 100% content of CO.

  2. Bed bug deterrence

    Directory of Open Access Journals (Sweden)

    Haynes Kenneth F

    2010-09-01

    Full Text Available Abstract A recent study in BMC Biology has determined that the immature stage of the bed bug (the nymph signals its reproductive status to adult males using pheromones and thus avoids the trauma associated with copulation in this species. The success of this nymphal strategy of deterrence is instructive. Against the background of increasing problems with bed bugs, this research raises the question whether pheromones might be used to control them. See research article http://www.biomedcentral.com/1741-7007/8/121

  3. The Safety of Hospital Beds

    Science.gov (United States)

    Gervais, Pierre; Pooler, Charlotte; Merryweather, Andrew; Doig, Alexa K.; Bloswick, Donald

    2015-01-01

    To explore the safety of the standard and the low hospital bed, we report on a microanalysis of 15 patients’ ability to ingress, move about the bed, and egress. The 15 participants were purposefully selected with various disabilities. Bed conditions were randomized with side rails up or down and one low bed with side rails down. We explored the patients’ use of the side rails, bed height, ability to lift their legs onto the mattress, and ability to turn, egress, and walk back to the chair. The standard bed was too high for some participants, both for ingress and egress. Side rails were used by most participants when entering, turning in bed, and exiting. We recommend that side rails be reconsidered as a means to facilitate in-bed movement, ingress, and egress. Furthermore, single deck height settings for all patients are not optimal. Low beds as a safety measure must be re-evaluated. PMID:28462302

  4. Hydrodynamic characterization of fluid bed cokers

    Energy Technology Data Exchange (ETDEWEB)

    Knapper, B. [Saskatchewan Univ., Saskatoon, SK (Canada); Berruti, F. [Western Ontario Univ., London, ON (Canada); Grace, J.R.; Bi, H.T.; Lim, C.J. [British Columbia Univ., Vancouver, BC (Canada)

    2002-07-01

    Syncrude Canada Ltd. uses fluid bed cokers for thermal conversion of bitumen from Northern Alberta tar sands into distillates. This paper presents the results of a study that examined the hydrodynamic characteristics of a geometrically and dynamically scaled-down cold flow model of an industrial fluid bed coker. The cold flow model was constructed with Plexiglass with a semi-circular geometry to enable flow visualization of the solid particles. Several operating conditions were examined and measured for key characteristic parameters. Local void fractions were measured with an optical fibre probe, and a suction probe was used to determine the local solids mass fluxes at varying radial and axial locations of the fluidized bed. It was determined that there are large axial and radial variations in both the local voidage and solids mass flux in terms of gas-solids flow. The core-annulus model for dilute riser flow gives unsatisfactory predictions because the model is not able to forecast radial variations in the annular region. A modified core-annulus flow model was developed to address this problem. The modified model has continuous profiles for the gas velocity and solids flux to significantly improve predictions.16 refs., 1 tab., 3 figs.

  5. Pressure Core Characterization

    Science.gov (United States)

    Santamarina, J. C.

    2014-12-01

    Natural gas hydrates form under high fluid pressure and low temperature, and are found in permafrost, deep lakes or ocean sediments. Hydrate dissociation by depressurization and/or heating is accompanied by a multifold hydrate volume expansion and host sediments with low permeability experience massive destructuration. Proper characterization requires coring, recovery, manipulation and testing under P-T conditions within the stability field. Pressure core technology allows for the reliable characterization of hydrate bearing sediments within the stability field in order to address scientific and engineering needs, including the measurement of parameters used in hydro-thermo-mechanical analyses, and the monitoring of hydrate dissociation under controlled pressure, temperature, effective stress and chemical conditions. Inherent sampling effects remain and need to be addressed in test protocols and data interpretation. Pressure core technology has been deployed to study hydrate bearing sediments at several locations around the world. In addition to pressure core testing, a comprehensive characterization program should include sediment analysis, testing of reconstituted specimens (with and without synthetic hydrate), and in situ testing. Pressure core characterization technology can be used to study other gas-charged formations such as deep sea sediments, coal bed methane and gas shales.

  6. MULTISTAGE FLUIDIZED BED REACTOR

    Science.gov (United States)

    Jonke, A.A.; Graae, J.E.A.; Levitz, N.M.

    1959-11-01

    A multistage fluidized bed reactor is described in which each of a number of stages is arranged with respect to an associated baffle so that a fluidizing gas flows upward and a granular solid downward through the stages and baffles, whereas the granular solid stopsflowing downward when the flow of fluidizing gas is shut off.

  7. Fluidized bed combustion chamber

    Energy Technology Data Exchange (ETDEWEB)

    Kullendorff, A.; Wikner, J.

    1985-03-25

    The chamber is confined in a pressure vessel. The lower part of the chamber has tilted parallel gutters up to the height of the fluidized bed. The slope of the gutter walls is 5 degrees-15 degrees and the top area of the gutters is 1.3 to 3 times larger than their bottom.

  8. Bed Bug Myths

    Science.gov (United States)

    Learn the truth about bed bugs, such as how easy they are to see with the naked eye, their preferred habitat, whether they transmit diseases, their public health effects, and whether pesticides are the best way to deal with an infestation.

  9. Surviving Bed Rest

    Science.gov (United States)

    ... your pregnancy — and your bed rest start a family tree that you can share with your child someday firm up your baby-name choices; use books and websites for ideas organize photo albums read anything — ... people (friends and family) whom you know will probably give gifts build ...

  10. Uncertainty and sensitivity analysis of filling fraction of pebble bed in pebble bed HTR

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hao, E-mail: haochen.heu@163.com [Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, College of Nuclear Science and Technology, Harbin Engineering University, Harbin (China); Institute of Nuclear and New Energy Technology (INET), Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing (China); Fu, Li; Jiong, Guo; Lidong, Wang [Institute of Nuclear and New Energy Technology (INET), Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing (China)

    2015-10-15

    Highlights: • An analysis approach is proposed to conduct SAU analysis of filling fraction of pebble bed core. • The contribution of uncertainty in filling fraction to key parameters of pebble bed core is quantified. • The primary drivers of the uncertainty in the key parameters are identified by sensitivity analysis. • Mechanism of effect of uncertainty in the filling fraction to key parameters is studied in depth. - Abstract: The filling fraction of pebble bed in each small region has some uncertainty, which will contribute to the total uncertainty in the key parameters of pebble bed core, such as power peak, axial offset, k{sub eff} and so on. In fact, the heavy metal content and graphite content of the corresponding region will change synchronously due to the perturbation of filling fraction but the ratio of atomic number density of moderator to the fuel (carbon–uranium) is still constant. To investigate these effects, the Chinese demonstration plant HTR-PM was selected as the research object and the VSOP code and CUSA package were used to conduct detailed analysis of the influence of the uncertainty in the filling fraction on the HTR-PM output variables of interest, based on the propagation of input uncertainties by using statistical sampling method to calculate uncertainty and sensitivity information from the simulation results. At the same time, uncertainty and sensitivity analysis of uranium loading had also been conducted for comparative analysis to study the mechanism of effect of uncertainty in the filling fraction to key parameters, and therefore only the heavy metal content of the corresponding region changes in the presence of perturbation of uranium loading. Finally, the propagated uncertainty in the power peak, axial offset and k{sub eff} of HTR-PM core was obtained and the primary drivers of the uncertainty in the key parameters were identified by sensitivity analysis.

  11. Numerical simulation of nuclear pebble bed configurations

    Energy Technology Data Exchange (ETDEWEB)

    Shams, A., E-mail: shams@nrg.eu [Nuclear Research and Consultancy Group (NRG), Petten (Netherlands); Roelofs, F., E-mail: roelofs@nrg.eu [Nuclear Research and Consultancy Group (NRG), Petten (Netherlands); Komen, E.M.J., E-mail: komen@nrg.eu [Nuclear Research and Consultancy Group (NRG), Petten (Netherlands); Baglietto, E., E-mail: emiliob@MIT.EDU [Massachusetts Institute of Technology (MIT) (United States)

    2015-08-15

    Highlights: • Numerical simulations of a single face cubic centred pebble bed are performed. • Wide range of turbulence modelling techniques are used to perform these calculations. • The methods include 1-DNS, 1-LES, 3-Hybrid (RANS/LES) and 3-RANS models, respectively. • The obtained results are extensively compared to provide guidelines for such flow regimes. • These guidelines are used to perform reference LES for a limited sized random pebble bed. - Abstract: High Temperature Reactors (HTRs) are being considered all over the world. An HTR uses helium gas as a coolant, while the moderator function is taken up by graphite. The fuel is embedded in the graphite moderator. A particular inherent safety advantage of HTR designs is that the graphite can withstand very high temperatures, that the fuel inside will stay inside the graphite pebble and cannot escape to the surroundings even in the event of loss of cooling. Generally, the core can be designed using a graphite pebble bed. Some experimental and demonstration reactors have been operated using a pebble bed design. The test reactors have shown safe and efficient operation, however questions have been raised about possible occurrence of local hot spots in the pebble bed which may affect the pebble integrity. Analysis of the fuel integrity requires detailed evaluation of local heat transport phenomena in a pebble bed, and since such phenomena cannot easily be modelled experimentally, numerical simulations are a useful tool. As a part of a European project, named Thermal Hydraulics of Innovative Nuclear Systems (THINS), a benchmarking quasi-direct numerical simulation (q-DNS) of a well-defined pebble bed configuration has been performed. This q-DNS will serve as a reference database in order to evaluate the prediction capabilities of different turbulence modelling approaches. A wide range of numerical simulations based on different available turbulence modelling approaches are performed and compared with

  12. Ice cores

    DEFF Research Database (Denmark)

    Svensson, Anders

    2014-01-01

    Ice cores from Antarctica, from Greenland, and from a number of smaller glaciers around the world yield a wealth of information on past climates and environments. Ice cores offer unique records on past temperatures, atmospheric composition (including greenhouse gases), volcanism, solar activity......, dustiness, and biomass burning, among others. In Antarctica, ice cores extend back more than 800,000 years before present (Jouzel et al. 2007), whereas. Greenland ice cores cover the last 130,000 years...

  13. Ice cores

    DEFF Research Database (Denmark)

    Svensson, Anders

    2014-01-01

    Ice cores from Antarctica, from Greenland, and from a number of smaller glaciers around the world yield a wealth of information on past climates and environments. Ice cores offer unique records on past temperatures, atmospheric composition (including greenhouse gases), volcanism, solar activity......, dustiness, and biomass burning, among others. In Antarctica, ice cores extend back more than 800,000 years before present (Jouzel et al. 2007), whereas. Greenland ice cores cover the last 130,000 years...

  14. Bathing a patient in bed

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000427.htm Bathing a patient in bed To use the sharing features on this page, please enable JavaScript. Some patients cannot safely leave their beds to bathe. For ...

  15. VA National Bed Control System

    Data.gov (United States)

    Department of Veterans Affairs — The VA National Bed Control System records the levels of operating, unavailable and authorized beds at each VAMC, and it tracks requests for changes in these levels....

  16. Thorium utilization program. Quarterly progress report for the period ending November 30, 1975. [Fuel element crushing, solids handling, fluidized bed combustion, aqueous separations, solvent extraction, systems design and drafting, alternative head-end reprocessing, and fuel recycle systems analysis

    Energy Technology Data Exchange (ETDEWEB)

    1975-12-31

    The development program for HTGR fuel reprocessing continues to emphasize the design and construction of a prototype head-end line. Design work on the multistage crushing system, the primary and secondary fluidized bed burners, the pneumatic transfer systems, and the ancillary fixtures for semiremote assembly and disassembly is essentially complete. Fabrication and receipt of all major components is under way, and auxiliary instrumentation and support systems are being installed. Studies of flow characteristics of granular solids in pneumatic transfer systems are continuing and data are being collected for use in design of systems for solids handling. Experimental work on the 20-cm primary fluidized bed burner verified the fines recycle operating mode in runs of greater than 24 hr. Twelve leaching runs were performed during the quarter using crushed, burned-back TRISO coated ThC/sub 2/ particles and burned-back BISO coated sol gel ThO/sub 2/ particles to examine the effect of varying the Thorex-to-thoria ratio to give product solutions ranging from 0.25M to 1M in thorium. Only minor effects were observed and reference values for facility operations were specified. Two-stage leaching runs with burned-back ThC/sub 2/ indicate there are no measurable differences in total dissolution time as compared to single-stage leaching. Bench-scale tests on oxidation of HTGR fuel boron carbide at 900/sup 0/C indicates that most if not all of the carbide will be converted to boron oxide in the fluidized bed burner. Eight solvent extraction runs were completed during the quarter. These runs represented the first cycle and second uranium cycle of the acid-Thorex flowsheet. A detailed calculation of spent fuel compositions by fuel block and particle type is being performed for better definition of process streams in a fuel reprocessing facility.

  17. Safety-related Innovative Nuclear Reactor Technology Elements R and D (SINTER) Network and Global HTGR R and D Network (GHTRN). Strategic benefits of international networking

    Energy Technology Data Exchange (ETDEWEB)

    Von Lensa, W. [Institut fuer Sicherheitsforschung und Reaktortechnik ISR, Forschungszentrum Juelich, Juelich (Germany)

    1998-09-01

    Action on `Safety-related Innovative Nuclear Reactor Technology Elements - R and D - (SINTER) Network` both aim at the identification of priority items for sustainable innovations of nuclear technologies and work-shared European collaboration structures. Such an approach can also be realised for future R and D on HTGR-related R and D under the umbrella of the IAEA as already proposed by the `International Working Group on Gas-Cooled Reactors (IWGGCR)` in 1996 and illustrated in this paper for the construction of a `Global HTGR R and D Network (GHTRN)`. 3 refs.

  18. Geomechanics of bedded salt

    Energy Technology Data Exchange (ETDEWEB)

    Serata, S.; Milnor, S.W.

    1979-06-08

    Creep data from the literature search is reinterpreted by SGI, resulting in a better understanding of the temperature and stress state dependence of the octahedral creep rate and the octahedral shear strength. The concept of a transition strength between the elastic and the plastic states is in agreement with the data. The elastic and rheological properties of salt are described, and a set of constitutive equations is presented. The dependence of material properties on parameters such as temperature is considered. Findings on the permeability of salt are summarized, and the in-situ behavior of openings in bedded salt is described based on extensive engineering experience. A stress measuring system utilizing a finite element computer code is discussed. Geological factors affecting the stability of salt openings are considered, and the Stress Control Technique for designing stable openings in bedded salt formations is explained.

  19. Fluidisation and dispersion behaviour of small high density pellicular expanded bed adsorbents

    DEFF Research Database (Denmark)

    Theodossiou, Irini; Elsner, H.D.; Thomas, Owen R. T.;

    2002-01-01

    The fluidisation and dispersion properties of various agarose-based expanded bed matrices-small high density stainless steel cored prototypes and standard commercial types-were studied in I-cm diameter expanded bed contactors in which fluid entering the column base is locally stirred. In all cases...

  20. Virtual Test Bed

    Science.gov (United States)

    2016-06-07

    project is to develop a benchmark system for evaluating models for predicting the characteristics of ocean wind waves. SCIENTIFIC OBJECTIVES A...transformation-scale models (i.e. models which treat the physics of waves propagating from offshore areas into the coastline). Each phase is further divided...to be assembled within the virtual test bed. Wind fields for running these tests will be obtained from Oceanweather, Inc. from a separate ONR

  1. Four Bed Molecular Sieve - Exploration (4BMS-X) Virtual Heater Design and Optimization

    Science.gov (United States)

    Schunk, R. Gregory; Peters, Warren T.; Thomas, John T., Jr.

    2017-01-01

    A 4BMS-X (Four Bed Molecular Sieve - Exploration) design and heater optimization study for CO2 sorbent beds in proposed exploration system architectures is presented. The primary objectives of the study are to reduce heater power and thermal gradients within the CO2 sorbent beds while minimizing channeling effects. Some of the notable changes from the ISS (International Space Station) CDRA (Carbon Dioxide Removal Assembly) to the proposed exploration system architecture include cylindrical beds, alternate sorbents and an improved heater core. Results from both 2D and 3D sorbent bed thermal models with integrated heaters are presented. The 2D sorbent bed models are used to optimize heater power and fin geometry while the 3D models address end effects in the beds for more realistic thermal gradient and heater power predictions.

  2. Gas turbine and advanced HTGR materials screening test program: 10,000-hour results and semiannual progress report for the period ending March 31, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Rosenwasser, S.N.; Johnson, W.R.

    1977-07-01

    Work on the Gas-Turbine and Advanced High-Temperature Gas-Cooled Reactor (HTGR) Materials Screening Test Program is documented. Emphasis is on the results and analyses of creep data to 11,000 hr and the detailed metallurgical evaluations performed on candidate alloy specimens tested for up to 10,000 hr. Long-term creep and unstressed aging data in controlled-impurity helium and in air at 650, 800, and 900/sup 0/C are reported for the original alloys in the program, including the vacuum-cast Ni-base superalloys, IN 100, Rene 100, IN 713, MM 004, M 21, and IN 738; the wrought solid-solution-strengthened Ni--Cr alloys, Hastelloy X and Inconel 617; the centrifugally-cast austenitic Fe--Ni--Cr alloy, IN 519; the oxide-dispersion-strengthened (ODS) Ni--Cr alloys, MA 753 and MA 754; and the wrought Mo-base alloy, MoTZM. Results at 650/sup 0/C and 10,000 hr for the precipitation-strengthened alloys Inconel 718, Inconel 706, and A 286 are also included. Similar, but much shorter term data at 800, 900, and 1000/sup 0/C for the recently added wrought alloys Hastelloy X (second heat), Hastelloy S, RA 333, and HD 556, and the additional centrifugally-cast alloys HK 40, Supertherm, Manaurite 36X, Manaurige 36XS, and Manaurite 900, are also reported.

  3. Understanding and predicting bed humidity in fluidized bed granulation.

    Science.gov (United States)

    Hu, Xinhui; Cunningham, John; Winstead, Denita

    2008-04-01

    Bed humidity is a critical parameter that needs to be controlled in a fluidized bed granulation to ensure reliability. To predict and control the bed humidity during the fluidized bed granulation process, a simple model based on the mass conservation of moisture was developed. The moisture mass balance model quantitatively simulates the effects of spray rate, binder solution concentration, airflow rate, inlet air temperature, and dew point on the bed humidity. The model was validated by a series of granulations performed in different scale granulators including Glatt GPCG-1, GPCG-15, and GPCG-60. Good agreement was observed between the theoretical prediction and the measured loss on drying (LOD). The model developed in the current work enables us to choose the appropriate parameters for the fluidized bed granulation and can be used as a valuable tool in process scaling-up.

  4. Coal Bed Methane Primer

    Energy Technology Data Exchange (ETDEWEB)

    Dan Arthur; Bruce Langhus; Jon Seekins

    2005-05-25

    During the second half of the 1990's Coal Bed Methane (CBM) production increased dramatically nationwide to represent a significant new source of income and natural gas for many independent and established producers. Matching these soaring production rates during this period was a heightened public awareness of environmental concerns. These concerns left unexplained and under-addressed have created a significant growth in public involvement generating literally thousands of unfocused project comments for various regional NEPA efforts resulting in the delayed development of public and fee lands. The accelerating interest in CBM development coupled to the growth in public involvement has prompted the conceptualization of this project for the development of a CBM Primer. The Primer is designed to serve as a summary document, which introduces and encapsulates information pertinent to the development of Coal Bed Methane (CBM), including focused discussions of coal deposits, methane as a natural formed gas, split mineral estates, development techniques, operational issues, producing methods, applicable regulatory frameworks, land and resource management, mitigation measures, preparation of project plans, data availability, Indian Trust issues and relevant environmental technologies. An important aspect of gaining access to federal, state, tribal, or fee lands involves education of a broad array of stakeholders, including land and mineral owners, regulators, conservationists, tribal governments, special interest groups, and numerous others that could be impacted by the development of coal bed methane. Perhaps the most crucial aspect of successfully developing CBM resources is stakeholder education. Currently, an inconsistent picture of CBM exists. There is a significant lack of understanding on the parts of nearly all stakeholders, including industry, government, special interest groups, and land owners. It is envisioned the Primer would being used by a variety of

  5. Bed Rest Muscular Atrophy

    Science.gov (United States)

    Greenleaf, John E.

    2000-01-01

    A major debilitating response from prolonged bed rest (BR) is muscle atrophy, defined as a "decrease in size of a part of tissue after full development has been attained: a wasting away of tissue as from disuse, old age, injury or disease". Part of the complicated mechanism for the dizziness, increased body instability, and exaggerated gait in patients who arise immediately after BR may be a result of not only foot pain, but also of muscular atrophy and associated reduction in lower limb strength. Also, there seems to be a close association between muscle atrophy and bone atrophy. A discussion of many facets of the total BR homeostatic syndrome has been published. The old adage that use determines form which promotes function of bone (Wolff's law) also applies to those people exposed to prolonged BR (without exercise training) in whom muscle atrophy is a consistent finding. An extreme case involved a 16-year-old boy who was ordered to bed by his mother in 1932: after 50 years in bed he had "a lily-white frame with limbs as thin as the legs of a ladder-back chair". These findings emphasize the close relationship between muscle atrophy and bone atrophy. In addition to loss of muscle mass during deconditioning, there is a significant loss of muscle strength and a decrease in protein synthesis. Because the decreases in force (strength) are proportionately greater than those in fiber size or muscle cross-sectional area, other contributory factors must be involved; muscle fiber dehydration may be important.

  6. Bed Rest Muscular Atrophy

    Science.gov (United States)

    Greenleaf, John E.

    2000-01-01

    A major debilitating response from prolonged bed rest (BR) is muscle atrophy, defined as a "decrease in size of a part of tissue after full development has been attained: a wasting away of tissue as from disuse, old age, injury or disease". Part of the complicated mechanism for the dizziness, increased body instability, and exaggerated gait in patients who arise immediately after BR may be a result of not only foot pain, but also of muscular atrophy and associated reduction in lower limb strength. Also, there seems to be a close association between muscle atrophy and bone atrophy. A discussion of many facets of the total BR homeostatic syndrome has been published. The old adage that use determines form which promotes function of bone (Wolff's law) also applies to those people exposed to prolonged BR (without exercise training) in whom muscle atrophy is a consistent finding. An extreme case involved a 16-year-old boy who was ordered to bed by his mother in 1932: after 50 years in bed he had "a lily-white frame with limbs as thin as the legs of a ladder-back chair". These findings emphasize the close relationship between muscle atrophy and bone atrophy. In addition to loss of muscle mass during deconditioning, there is a significant loss of muscle strength and a decrease in protein synthesis. Because the decreases in force (strength) are proportionately greater than those in fiber size or muscle cross-sectional area, other contributory factors must be involved; muscle fiber dehydration may be important.

  7. Racing for the Bed

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    No one knows when the people ofMacheng City began to employthe marriage custom of racingfor the bed, once a custom unique to theTujia ethnic minority. It is said that at the end of awedding, bride and bridegroom enter thebridal chamber together and race for thebed. The one who is the first to sit on thebed will be the master of the new familyIt sounds unreasonable, but quite anumber of people believe in it.Therefore, on the wedding night, manybrides and bridegrooms try their best to

  8. Biparticle fluidized bed reactor

    Science.gov (United States)

    Scott, C.D.

    1993-12-14

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase is described. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figures.

  9. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2010-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  10. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2008-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  11. 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

  12. 球床高温气冷堆闭式循环特性%Characteristics of closed fuel cycles in the pebble bed high temperature gas cooled reactor

    Institute of Scientific and Technical Information of China (English)

    位金锋; 孙玉良; 李富

    2012-01-01

    The reuse of uranium and plutonium from high temperature gas-cooled reactor(HTGR) spent fuel will improve resource usage and minimize waste.The characteristics of different closed fuel cycles were studied here for uranium and plutonium recycled from 250 MWth high-temperature gas-cooled reactor pebble-bed-module(HTR-PM) spent fuel from a U-Pu fueled core.PuO2 and MOX fuel elements using recycled plutonium and uranium were then used in new PuO2 or MOX fueled cores with the same geometry as the original reactor.PuO2 from LWR spent fuel was also evaluated.The characteristics of the fuel utilization and transuranic incineration in these closed fuel cycles were studied with the VSOP program.The natural uranium utilization closed fuel for these closed fuel cycle is increased by 6%,8% and 20%,while the plutonium burn rates are 40%,41% and 63%,respectively.Thus,these HTGR closed fuel cycles can effectively burn plutonium isotopes and increase natural uranium utilization.%从提高天然铀利用率和改进废物管理方面考虑,研究球床高温气冷堆乏燃料中铀钚的再利用和不同闭式燃料循环的特性。在250MW热功率球床模块式高温气冷堆示范电站铀钚循环的乏燃料中提取铀和钚为核燃料,设计了PuO2和混合氧化物(MOX)燃料元件,将新设计的燃料元件重新装入与示范电站有同样结构和尺寸的堆芯,分别形成纯钚燃料循环和MOX燃料循环。还研究了基于轻水堆级钚的燃料循环。采用了高温气冷堆物理设计程序VSOP,研究了高温气冷堆不同闭式循环的燃料利用和超铀元素焚烧特性。不同闭式循环钚消耗率分别为50%、46%和71%,天然铀的电利用率分别提高了6%、8%和20%。结果表明:高温气冷堆闭式燃料循环能有效焚烧钚同位素,适度提高天然铀的利用率。

  13. Variability of Bed Drag on Cohesive Beds under Wave Action

    Directory of Open Access Journals (Sweden)

    Ilgar Safak

    2016-04-01

    Full Text Available Drag force at the bed acting on water flow is a major control on water circulation and sediment transport. Bed drag has been thoroughly studied in sandy waters, but less so in muddy coastal waters. The variation of bed drag on a muddy shelf is investigated here using field observations of currents, waves, and sediment concentration collected during moderate wind and wave events. To estimate bottom shear stress and the bed drag coefficient, an indirect empirical method of logarithmic fitting to current velocity profiles (log-law, a bottom boundary layer model for combined wave-current flow, and a direct method that uses turbulent fluctuations of velocity are used. The overestimation by the log-law is significantly reduced by taking turbulence suppression due to sediment-induced stratification into account. The best agreement between the model and the direct estimates is obtained by using a hydraulic roughness of 10 - 4 m in the model. Direct estimate of bed drag on the muddy bed is found to have a decreasing trend with increasing current speed, and is estimated to be around 0.0025 in conditions where wave-induced flow is relatively weak. Bed drag shows an increase (up to fourfold with increasing wave energy. These findings can be used to test the bed drag parameterizations in hydrodynamic and sediment transport models and the skills of these models in predicting flows in muddy environments.

  14. Variability of bed drag on cohesive beds under wave action

    Science.gov (United States)

    Safak, Ilgar

    2016-01-01

    Drag force at the bed acting on water flow is a major control on water circulation and sediment transport. Bed drag has been thoroughly studied in sandy waters, but less so in muddy coastal waters. The variation of bed drag on a muddy shelf is investigated here using field observations of currents, waves, and sediment concentration collected during moderate wind and wave events. To estimate bottom shear stress and the bed drag coefficient, an indirect empirical method of logarithmic fitting to current velocity profiles (log-law), a bottom boundary layer model for combined wave-current flow, and a direct method that uses turbulent fluctuations of velocity are used. The overestimation by the log-law is significantly reduced by taking turbulence suppression due to sediment-induced stratification into account. The best agreement between the model and the direct estimates is obtained by using a hydraulic roughness of 10  m in the model. Direct estimate of bed drag on the muddy bed is found to have a decreasing trend with increasing current speed, and is estimated to be around 0.0025 in conditions where wave-induced flow is relatively weak. Bed drag shows an increase (up to fourfold) with increasing wave energy. These findings can be used to test the bed drag parameterizations in hydrodynamic and sediment transport models and the skills of these models in predicting flows in muddy environments.

  15. Ice Cores

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature, precipitation, atmospheric trace gases, and other aspects of climate and environment derived from ice cores drilled on glaciers and ice...

  16. Core BPEL

    DEFF Research Database (Denmark)

    Hallwyl, Tim; Højsgaard, Espen

    extensions. Combined with the fact that the language definition does not provide a formal semantics, it is an arduous task to work formally with the language (e.g. to give an implementation). In this paper we identify a core subset of the language, called Core BPEL, which has fewer and simpler constructs......, does not allow omissions, and does not contain ignorable elements. We do so by identifying syntactic sugar, including default values, and ignorable elements in WS-BPEL. The analysis results in a translation from the full language to the core subset. Thus, we reduce the effort needed for working...... formally with WS-BPEL, as one, without loss of generality, need only consider the much simpler Core BPEL. This report may also be viewed as an addendum to the WS-BPEL standard specification, which clarifies the WS-BPEL syntax and presents the essential elements of the language in a more concise way...

  17. Core BPEL

    DEFF Research Database (Denmark)

    Hallwyl, Tim; Højsgaard, Espen

    extensions. Combined with the fact that the language definition does not provide a formal semantics, it is an arduous task to work formally with the language (e.g. to give an implementation). In this paper we identify a core subset of the language, called Core BPEL, which has fewer and simpler constructs......, does not allow omissions, and does not contain ignorable elements. We do so by identifying syntactic sugar, including default values, and ignorable elements in WS-BPEL. The analysis results in a translation from the full language to the core subset. Thus, we reduce the effort needed for working...... formally with WS-BPEL, as one, without loss of generality, need only consider the much simpler Core BPEL. This report may also be viewed as an addendum to the WS-BPEL standard specification, which clarifies the WS-BPEL syntax and presents the essential elements of the language in a more concise way...

  18. Core benefits

    National Research Council Canada - National Science Library

    Keith, Brian W

    2010-01-01

    This SPEC Kit explores the core employment benefits of retirement, and life, health, and other insurance -benefits that are typically decided by the parent institution and often have significant governmental regulation...

  19. Multiscale Analysis of Pebble Bed Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hans Gougar; Woo Yoon; Abderrafi Ougouag

    2010-10-01

    – The PEBBED code was developed at the Idaho National Laboratory for design and analysis of pebble-bed high temperature reactors. The diffusion-depletion-pebble-mixing algorithm of the original PEBBED code was enhanced through coupling with the THERMIX-KONVEK code for thermal fluid analysis and by the COMBINE code for online cross section generation. The COMBINE code solves the B-1 or B-3 approximations to the transport equation for neutron slowing down and resonance interactions in a homogeneous medium with simple corrections for shadowing and thermal self-shielding. The number densities of materials within specified regions of the core are averaged and transferred to COMBINE from PEBBED for updating during the burnup iteration. The simple treatment of self-shielding in previous versions of COMBINE led to inaccurate results for cross sections and unsatisfactory core performance calculations. A new version of COMBINE has been developed that treats all levels of heterogeneity using the 1D transport code ANISN. In a 3-stage calculation, slowing down is performed in 167 groups for each homogeneous subregion (kernel, particle layers, graphite shell, control rod absorber annulus, etc.) Particles in a local average pebble are homogenized using ANISN then passed to the next (pebble) stage. A 1D transport solution is again performed over the pebble geometry and the homogenized pebble cross sections are passed to a 1-d radial model of a wedge of the pebble bed core. This wedge may also include homogeneous reflector regions and a control rod region composed of annuli of different absorbing regions. Radial leakage effects are therefore captured with discrete ordinates transport while axial and azimuthal effects are captured with a transverse buckling term. In this paper, results of various PBR models will be compared with comparable models from literature. Performance of the code will be assessed.

  20. Wave interaction with large roughness elements on an impermeable sloping bed

    DEFF Research Database (Denmark)

    Jensen, Bjarne; Christensen, Erik Damgaard; Sumer, B. Mutlu

    2012-01-01

    is on the details in the porous core flow and the armour layer flow i.e. the interaction between the two flow domains and the effect on the armour layer stability. In order to isolate the processes involved with the flow in the porous core the investigations are first carried out with a completely impermeable bed...

  1. Thorium utilization program. Quarterly progress report for the period ending May 31, 1976. [Fuel element crushing, solids handling, fluidized-bed combustion, aqueous separations, solvent extraction, off-gas studies, semiremote handling systems, alternative head-end processing, and fuel recycle design

    Energy Technology Data Exchange (ETDEWEB)

    1976-06-30

    The work reported includes the development of unit processes and equipment for reprocessing of High-Temperature Gas-Cooled Reactor (HTGR) fuel and the design and development of an integrated line to demonstrate the head end of HTGR reprocessing using unirradiated fuel materials. Work is also described on trade-off studies concerning the required design of recycle facilities for the large-scale recycle of HTGR fuels in order to guide the development activities for HTGR fuel recycle.

  2. Effectiveness of Bed Bug Pesticides

    Science.gov (United States)

    Before EPA allows a bed bug claim on a label, the product must be supported by data showing it will kill bed bugs when applied according to the label. Also consider factors such as extent of infestation, site preparation, and insect life stages.

  3. Bed Bug Laws and Regulations

    Science.gov (United States)

    21 states have some level of regulation with regard to bed bugs. Most of these requirements focus on hotels and landlords or other property managers. The Department of Housing and Urban Development has guidance on controlling bed bugs in public housing.

  4. PIV Visualization of Bubble Induced Flow Circulation in 2-D Rectangular Pool for Ex-Vessel Debris Bed Coolability

    Energy Technology Data Exchange (ETDEWEB)

    Han, Teayang; Kim, Eunho; Park, Hyun Sun; Moriyama, Kiyofumi [POSTECH, Pohang (Korea, Republic of)

    2015-10-15

    The previous research works demonstrated the debris bed formation on the flooded cavity floor in experiments. Even in the cases the core melt is once solidified, the debris bed can be re-melted due to the decay heat. If the debris bed is not cooled enough by the coolant, the re-melted debris bed will react with the concrete base mat. This situation is called the molten core-concrete interaction (MCCI) which threatens the integrity of the containment by generated gases which pressurize the containment. Therefore securing the long term coolability of the debris bed in the cavity is crucial. According to the previous research works, the natural convection driven by the rising bubbles affects the coolability and the formation of the debris bed. Therefore, clarification of the natural convection characteristics in and around the debris bed is important for evaluation of the coolability of the debris bed. In this study, two-phase flow around the debris bed in a 2D slice geometry is visualized by PIV method to obtain the velocity map of the flow. The DAVINCI-PIV was developed to investigate the flow around the debris bed. In order to simulate the boiling phenomena induced by the decay heat of the debris bed, the air was injected separately by the air chamber system which consists of the 14 air-flowmeters. The circulation flow developed by the rising bubbles was visualized by PIV method.

  5. Debris-bed friction of hard-bedded glaciers

    Science.gov (United States)

    Cohen, D.; Iverson, N.R.; Hooyer, T.S.; Fischer, U.H.; Jackson, M.; Moore, P.L.

    2005-01-01

    [1] Field measurements of debris-bed friction on a smooth rock tablet at the bed of Engabreen, a hard-bedded, temperate glacier in northern Norway, indicated that basal ice containing 10% debris by volume exerted local shear traction of up to 500 kPa. The corresponding bulk friction coefficient between the dirty basal ice and the tablet was between 0.05 and 0.08. A model of friction in which nonrotating spherical rock particles are held in frictional contact with the bed by bed-normal ice flow can account for these measurements if the power law exponent for ice flowing past large clasts is 1. A small exponent (n glacier sliding at 20 m a-1 with a geothermally induced melt rate of 0.006 m a-1 and an effective pressure of 300 kPa can exceed 100 kPa. Debris-bed friction can therefore be a major component of sliding resistance, contradicting the common assumption that debris-bed friction is negligible. Copyright 2005 by the American Geophysical Union.

  6. Exercise thermoregulation with bed rest, confinement, and immersion deconditioning

    Science.gov (United States)

    Greenleaf, J. E.

    1997-01-01

    Altered thermoregulation following exposure to prolonged (12-14 days) of bed rest and 6 hr of head-down thermoneutral water immersion in humans, and cage confinement (8 weeks) in male, mongrel dogs resulted in occasional increased core temperature (Tcore) at rest, but consistent "excessive" increase in Tcore during submaximal exercise. This excessive increase in Tcore in nonexercising and exercising subjects was independent of the mode (isometric or isotonic) of exercise training during bed rest, and was associated with the consistent hypovolemia in men but not in women taking estrogen supplementation (1.25 mg premarin/ day) which restored plasma volume during bed rest to ambulatory control levels. Post-bed rest exercise sweating (evaporative heat loss) was unchanged or higher than control levels; however, calculated tissue heat conductance was significantly lower in men, and forearm venoconstriction was greater (venous volume was reduced) in women during exercise after bed rest. Because sweating appeared proportional to the increased level of Tcore, these findings suggest that one major factor for the excessive hyperthermia is decreased core to periphery heat conduction. Exercising dogs respond like humans with excessive increase in both rectal (Tre) and exercising muscle temperatures (Tmu) after confinement and, after eight weeks of exercise training on a treadmill following confinement, they had an attenuated rate of increase of Tre even below ambulatory control levels. Intravenous infusion of glucose also attenuated not only the rise in Tre during exercise in normal dogs, but also the excessive rise in Tre and exercising Tmu after confinement. Oral glucose also appeared to reduce the rate of increase in excessive Tre in men after immersion deconditioning. There was a greater rate of rise in Tcore in two cosmonauts during supine submaximal exercise (65% VO2 max) on the fifth recovery day after the 115-day Mir 18 mission. Thus, the excessive rise in core

  7. Realistic packed bed generation using small numbers of spheres

    Energy Technology Data Exchange (ETDEWEB)

    Pavlidis, D., E-mail: dimitrios.pavlidis04@imperial.ac.uk; Lathouwers, D.

    2013-10-15

    Highlights: • A method for generating 3D, periodic, closely packed beds of small numbers (<50) of spheres is presented. • The method is able to reproduce characteristics for the entirety (including nearwall area) of a randomly stacked bed. • Results are in good agreement with reference numerical data. -- Abstract: A method for stochastically generating three-dimensional, periodic, closely packed beds of small numbers (less than 50) of spheres is presented. This is an essential and integral part of realistic modelling of fluid flow and heat transfer through packed beds. In order to be able to reproduce the entirety of these complex geometries (in the radial direction) using small numbers of spheres, they are divided into two regions: the near-wall region (up to 4–5 sphere diameters from the solid wall in the wall-normal direction) and the core region. Near-wall stackings are doubly periodic and include a solid wall, while core stackings are triply periodic. A computational method for generating such geometries is presented for each region. Both are based on overlap removal methods. Results are compared against reference numerical data. Diagnostics used to evaluate the models include average packing fractions and coordination numbers, porosity profiles and distributions of the angle between two spheres which touch a common neighbour. Results are in good qualitative and quantitative agreement with the available reference data.

  8. Torsion testing of bed joints

    DEFF Research Database (Denmark)

    Hansen, Klavs Feilberg; Pedersen, Carsten Mørk

    2008-01-01

    be carried out directly in a normal testing machine. The torsion strength is believed to be the most important parameter in out-of-plane resistance of masonry walls subjected to bending about an axis perpendicular to the bed joints. The paper also contains a few test results from bending of small walls about...... an axis perpendicular to the bed joints, which indicate the close connection between these results and results from torsion tests. These characteristics make the torsion strength well suited to act as substitute parameter for the bending strength of masonry about an axis perpendicular to the bed joints....

  9. An improved design of TRISO particle with porous SiC inner layer by fluidized bed-chemical vapor deposition

    Science.gov (United States)

    Liu, Rongzheng; Liu, Malin; Chang, Jiaxing; Shao, Youlin; Liu, Bing

    2015-12-01

    Tristructural-isotropic (TRISO) particle has been successful in high temperature gas cooled reactor (HTGR), but an improved design is required for future development. In this paper, the coating layers are reconsidered, and an improved design of TRISO particle with porous SiC inner layer is proposed. Three methods of preparing the porous SiC layer, called high methyltrichlorosilane (MTS) concentration method, high Ar concentration method and hexamethyldisilane (HMDS) method, are experimentally studied. It is indicated that porous SiC layer can be successfully prepared and the density of SiC layer can be adjusted by tuning the preparation parameters. Microstructure and characterization of the improved TRISO coated particle are given based on scanning electron microscope (SEM), X-ray diffraction (XRD), Raman scattering and energy dispersive X-ray (EDX) analysis. It can be found that the improved TRISO coated particle with porous SiC layer can be mass produced successfully. The formation mechanisms of porous SiC layer are also discussed based on the fluidized bed-chemical vapor deposition principle.

  10. Annular core liquid-salt cooled reactor with multiple fuel and blanket zones

    Science.gov (United States)

    Peterson, Per F.

    2013-05-14

    A liquid fluoride salt cooled, high temperature reactor having a reactor vessel with a pebble-bed reactor core. The reactor core comprises a pebble injection inlet located at a bottom end of the reactor core and a pebble defueling outlet located at a top end of the reactor core, an inner reflector, outer reflector, and an annular pebble-bed region disposed in between the inner reflector and outer reflector. The annular pebble-bed region comprises an annular channel configured for receiving pebble fuel at the pebble injection inlet, the pebble fuel comprising a combination of seed and blanket pebbles having a density lower than the coolant such that the pebbles have positive buoyancy and migrate upward in said annular pebble-bed region toward the defueling outlet. The annular pebble-bed region comprises alternating radial layers of seed pebbles and blanket pebbles.

  11. Bed Bugs: The Australian Response

    Science.gov (United States)

    Doggett, Stephen L.; Orton, Christopher J.; Lilly, David G.; Russell, Richard C.

    2011-01-01

    Australia has experienced a sudden and unexpected resurgence in bed bug infestations from both Cimex lectularius L. and Cimex hemipterus F. A survey in 2006 revealed that infestations had increased across the nation by an average of 4,500% since the start of the decade. In response, a multi-disciplinary approach to combat the rise of this public health pest was implemented and involved the coordinated efforts of several organizations. The key components of the strategy included the introduction of a pest management standard ‘A Code of Practice for the Control of Bed Bug Infestations in Australia’ that defines and promotes ‘best practice’ in bed bug eradication, the development of a policy and procedural guide for accommodation providers, education of stakeholders in best management practices, and research. These strategies continue to evolve with developments that lead to improvements in ‘best practice’ while bed bugs remain problematic in Australia. PMID:26467616

  12. Top Ten Bed Bug Tips

    Science.gov (United States)

    ... temperatures are necessary for successful heat treatment. Black plastic bags in the sun might work to kill bed ... Place the used bag in a tightly sealed plastic bag and in an outside garbage bin. 10. Turn ...

  13. Bed Bugs: The Australian Response

    Directory of Open Access Journals (Sweden)

    Richard C. Russell

    2011-04-01

    Full Text Available Australia has experienced a sudden and unexpected resurgence in bed bug infestations from both Cimex lectularius L. and Cimex hemipterus F. A survey in 2006 revealed that infestations had increased across the nation by an average of 4,500% since the start of the decade. In response, a multi-disciplinary approach to combat the rise of this public health pest was implemented and involved the coordinated efforts of several organizations. The key components of the strategy included the introduction of a pest management standard ‘A Code of Practice for the Control of Bed Bug Infestations in Australia’ that defines and promotes ‘best practice’ in bed bug eradication, the development of a policy and procedural guide for accommodation providers, education of stakeholders in best management practices, and research. These strategies continue to evolve with developments that lead to improvements in ‘best practice’ while bed bugs remain problematic in Australia.

  14. Bed Bugs: The Australian Response.

    Science.gov (United States)

    Doggett, Stephen L; Orton, Christopher J; Lilly, David G; Russell, Richard C

    2011-04-15

    Australia has experienced a sudden and unexpected resurgence in bed bug infestations from both Cimex lectularius L. and Cimex hemipterus F. A survey in 2006 revealed that infestations had increased across the nation by an average of 4,500% since the start of the decade. In response, a multi-disciplinary approach to combat the rise of this public health pest was implemented and involved the coordinated efforts of several organizations. The key components of the strategy included the introduction of a pest management standard 'A Code of Practice for the Control of Bed Bug Infestations in Australia' that defines and promotes 'best practice' in bed bug eradication, the development of a policy and procedural guide for accommodation providers, education of stakeholders in best management practices, and research. These strategies continue to evolve with developments that lead to improvements in 'best practice' while bed bugs remain problematic in Australia.

  15. Print a Bed Bug Card

    Science.gov (United States)

    Two sets of business card-sized lists of tips for prevention of bed bug infestations, one for general use around home, the other for travelers. Print a single card or a page of cards for distribution.

  16. Torsion testing of bed joints

    DEFF Research Database (Denmark)

    Hansen, Klavs Feilberg; Pedersen, Carsten Mørk

    2008-01-01

    This paper describes a simple test method for determining the torsion strength of a single bed joint between two bricks and presents results from testing using this test method. The setup for the torsion test is well defined, require minimal preparation of the test specimen and the test can...... be carried out directly in a normal testing machine. The torsion strength is believed to be the most important parameter in out-of-plane resistance of masonry walls subjected to bending about an axis perpendicular to the bed joints. The paper also contains a few test results from bending of small walls about...... an axis perpendicular to the bed joints, which indicate the close connection between these results and results from torsion tests. These characteristics make the torsion strength well suited to act as substitute parameter for the bending strength of masonry about an axis perpendicular to the bed joints....

  17. Better backs by better beds?

    DEFF Research Database (Denmark)

    Bergholdt, Kim; Fabricius, Rasmus N; Bendix, Tom

    2008-01-01

    using the probably most relevant "worst case" data. There were no relevant difference between the effects of the water bed and the foam bed. CONCLUSION: The Waterbed and foam mattress' did influence back symptoms, function and sleep more positively as apposed to the hard mattress, but the differences...... mattresses have a positive effect on LBP, and especially a hard mattress is commonly believed to have a positive effect. METHODS: One hundred sixty CLBP patients were randomized to 1 of 3 groups, having a mattress/bed mounted in their sleeping room for 1 month. The beds were: (1) waterbed (Akva), (2) body......-conforming foam mattress (Tempur), and (3) a hard mattress (Innovation Futon). At baseline and after 4 weeks, a blinded observer interviewed the patients on LBP levels (0-10), daily function (activities of daily living, 0-30), and on the amount of sleeping hours/night. RESULTS: Because of dropout of 19 patients...

  18. Sea bed mapping and inspection

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The conference has 24 presentations on the topics: Sea bed mapping, inspection, positioning, hydrography, marine archaeology, remote operation vehicles and computerized simulation technologies, oil field activities and plans, technological experiences and problems. (tk)

  19. Bed bugs in healthcare settings.

    Science.gov (United States)

    Munoz-Price, L Silvia; Safdar, Nasia; Beier, John C; Doggett, Stephen L

    2012-11-01

    Infestations caused by bed bugs have resurfaced during the past decade across all continents. Even though bed bugs primarily cause skin manifestations in humans, a major stigma is placed upon people or institutions found to carry them. It is important for healthcare facilities to be prepared for this pest by implementing policies, carefully selecting materials used for hospital furniture, and educating providers on early identification and control.

  20. Bedømmelsens kompleksitet

    Directory of Open Access Journals (Sweden)

    Elsa Schmidt

    2006-03-01

    Full Text Available I artiklen sammenholdes hverdagens bedømmelser af mennesker med de bedømmelser, der sker ved eksaminer. Der er forskelle på grund af det retlige grundlag, men også ligheder. Konkrete erfaringer med klage- og ankesager gennem 8 år fra faget psykologi på landsplan opsummeres. Nogle få praktiske løsninger beskrives.

  1. Discrete element modelling of pebble packing in pebble bed reactors

    Energy Technology Data Exchange (ETDEWEB)

    Suikkanen, Heikki, E-mail: heikki.suikkanen@lut.fi; Ritvanen, Jouni, E-mail: jouni.ritvanen@lut.fi; Jalali, Payman, E-mail: payman.jalali@lut.fi; Kyrki-Rajamäki, Riitta, E-mail: riitta.kyrki-rajamaki@lut.fi

    2014-07-01

    Highlights: • A discrete element method code is developed for pebble bed reactor analyses. • Methods are established to extract packing information at various spatial scales. • Packing simulations inside annular core geometry are done varying input parameters. • The restitution coefficient has the strongest effect on the resulting packing density. • Detailed analyses reveal local densification especially near the walls. - Abstract: It is important to understand the packing characteristics and behaviour of the randomly packed pebble bed to further analyse the reactor physical and thermal-hydraulic behaviour and to design a safe and economically feasible pebble bed reactor. The objective of this work was to establish methods to model and analyse the pebble packing in detail to provide useful tools and data for further analyses. Discrete element method (DEM) is a well acknowledged method for analysing granular materials, such as the fuel pebbles in a pebble bed reactor. In this work, a DEM computer code was written specifically for pebble bed analyses. Analysis methods were established to extract data at various spatial scales from the pebble beds resulting from the DEM simulations. A comparison with available experimental data was performed to validate the DEM implementation. To test the code implementation in full-scale reactor calculations, DEM packing simulations were done in annular geometry with 450,000 pebbles. Effects of the initial packing configuration, friction and restitution coefficients and pebble size distribution to the resulting pebble bed were investigated. The packing simulations revealed that from the investigated parameters the restitution coefficient had the largest effect on the resulting average packing density while other parameters had smaller effects. Detailed local packing density analysis of pebble beds with different average densities revealed local variations especially strong in the regions near the walls. The implemented DEM

  2. Dual Fluidized Bed Biomass Gasification

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-09-30

    The dual fluidized bed reactor is a recirculating system in which one half of the unit operates as a steam pyrolysis device for biomass. The pyrolysis occurs by introducing biomass and steam to a hot fluidized bed of inert material such as coarse sand. Syngas is produced during the pyrolysis and exits the top of the reactor with the steam. A crossover arm, fed by gravity, moves sand and char from the pyrolyzer to the second fluidized bed. This sand bed uses blown air to combust the char. The exit stream from this side of the reactor is carbon dioxide, water and ash. There is a second gravity fed crossover arm to return sand to the pyrolysis side. The recirculating action of the sand and the char is the key to the operation of the dual fluidized bed reactor. The objective of the project was to design and construct a dual fluidized bed prototype reactor from literature information and in discussion with established experts in the field. That would be appropriate in scale and operation to measure the relative performance of the gasification of biomass and low ranked coals to produce a high quality synthesis gas with no dilution from nitrogen or combustion products.

  3. Stratum energy of coal-bed gas reservoir and their control on the coal-bed gas reservoir formation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Stratum energy of coal-bed gas reservoir, including coal-radix flexibility energy, groundwater flexibility energy and gas flexibility energy (hereinafter "three energy"), depends on the energy homeostasis system, the core process of which is the effective transfer of energy and the geological selective process. Combining with the mechanics experimentations of coal samples, different flexibility energy has been analyzed and researched quantificationally, and a profound discussion to their controls on the coal-bed gas reservoir formation has been made. It is shown that when gas reservoir is surrounded by edge water and bottom water, the deposited energy in the early phase of forming gas reservoir is mostly coal-radix and gas flexibility energy, but the effect of groundwater flexibility energy increases while water-body increases. The deposited energy in the middle and later phase of forming gas reservoir is mostly gas flexibility energy, which is greater than 80% of all deposited energy. In the whole process, larger groundwater body exerts greater influences on gas accumulation. The paper indicated that higher stratum energy is more propitious to forming coal-bed gas reservoir. And higher coal-radix flexibility energy and gas flexibility energy are more propitious to higher yield of gas reservoirs, while higher groundwater flexibility energy is more propitious to stable yield of gas reservoirs. Therefore, the key to evaluating the coal-bed gas reservoir formation is the stratum energy of coal-bed gas reservoir.

  4. Influence of Ordovician carbonate reservoir beds in Tarim Basin by faulting

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The quality of the Ordovician carbonate reservoir beds in the Tarim Basin is closely related to the development of secondary pores,fractures and cavities. Karstification is important in improving the properties of reservoir beds,and karstification related to unconformity has caught wide attention. Compared with the recent research on the unconformity karst reservoir bed improvement,this paper shows a new way of carbonate reservoir bed transformation. Based on field survey,core and slices observation,transformation of Ordovician carbonate reservoir beds by faulting can be classified into three types: (1) Secondary faults and fracturs generated by faulting improved carbonate reservoir bed properties,which were named the Lunnan or Tazhong82 model; (2) upflow of deep geothermal fluids caused by faulting,with some components metasomatizing with carbonate and forming some secon-dary deposit,such as fluorite. It can improve carbonate reservoir bed properties obviously and is named the Tazhong 82 model; and (3) the faulting extending up to the surface increased the depth of supergene karstification and the thickness of reservoir bed. It is named the Hetianhe model. Trans-formation effect of carbonate reservoir beds by faulting was very significant,mainly distributed on the slopes or on the edge or plunging end of the uplift.

  5. Core Java

    CERN Document Server

    Horstmann, Cay S

    2013-01-01

    Fully updated to reflect Java SE 7 language changes, Core Java™, Volume I—Fundamentals, Ninth Edition, is the definitive guide to the Java platform. Designed for serious programmers, this reliable, unbiased, no-nonsense tutorial illuminates key Java language and library features with thoroughly tested code examples. As in previous editions, all code is easy to understand, reflects modern best practices, and is specifically designed to help jumpstart your projects. Volume I quickly brings you up-to-speed on Java SE 7 core language enhancements, including the diamond operator, improved resource handling, and catching of multiple exceptions. All of the code examples have been updated to reflect these enhancements, and complete descriptions of new SE 7 features are integrated with insightful explanations of fundamental Java concepts.

  6. 49 CFR 236.336 - Locking bed.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locking bed. 236.336 Section 236.336 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Instructions § 236.336 Locking bed. The various parts of the locking bed, locking bed supports, and tappet...

  7. Comprehensive Mathematical Model for Coal Combustion in a Circulating Fluidized Bed Combustor

    Institute of Scientific and Technical Information of China (English)

    金晓钟; 吕俊复; 杨海瑞; 刘青; 岳光溪; 冯俊凯

    2001-01-01

    Char combustion is on a special reducing condition in the dense bed of a circulating fluidized bedcombustor. Experimental findings were used to develop a comprehensive mathematical model to simulate thehydrodynamic and combustion processes in a circulating fluidized bed combustor. In the model, gas-solidinteraction was used to account for the mass transfer between the bubble phase and the emulsion phase in thedense bed, which contributes to the reducing atmosphere in the dense bed. A core-annular structure wasassumed in the dilute area rather than a one-dimensional model. The submodels were combined to build thecomprehensive model to analyze the combustion in a circulating fluidized bed combustor and the effect ofoperating parameters on the coal combustion. The model predictions agree well with experimental results.

  8. Rapid ignition of fluidized bed boiler

    Science.gov (United States)

    Osborn, Liman D.

    1976-12-14

    A fluidized bed boiler is started up by directing into the static bed of inert and carbonaceous granules a downwardly angled burner so that the hot gases cause spouting. Air is introduced into the bed at a rate insufficient to fluidize the entire bed. Three regions are now formed in the bed, a region of lowest gas resistance, a fluidized region and a static region with a mobile region at the interface of the fluidized and static regions. Particles are transferred by the spouting action to form a conical heap with the carbonaceous granules concentrated at the top. The hot burner gases ignite the carbonaceous matter on the top of the bed which becomes distributed in the bed by the spouting action and bed movement. Thereafter the rate of air introduction is increased to fluidize the entire bed, the spouter/burner is shut off, and the entire fluidized bed is ignited.

  9. Empirical closures for particulate debris bed spreading induced by gas–liquid flow

    Energy Technology Data Exchange (ETDEWEB)

    Basso, S., E-mail: simoneb@kth.se; Konovalenko, A.; Kudinov, P.

    2016-02-15

    Highlights: • Experimental study of the debris bed self-leveling phenomenon. • A scaling approach and a non-dimensional model to describe particle flow rate are proposed. • The model is validated against experiments with particles of different properties and at different gas injection conditions. - Abstract: Efficient removal of decay heat from the nuclear reactor core debris is paramount for termination of severe accident progression. One of the strategies is based on melt fragmentation, quenching and cooling in a deep pool of water under the reactor vessel. Geometrical configuration of the debris bed is among the important factors which determine possibility of removing the decay heat from the debris bed by natural circulation of the coolant. For instance, a tall mound-shape debris bed can be non-coolable, while the same debris can be coolable if spread uniformly. Decay heat generates a significant amount of thermal energy which goes to production of steam inside the debris bed. Two-phase flow escaping through the top layer of the bed becomes a source of mechanical energy which can move the particulate debris along the slope of the bed. The motion of the debris will lead to flattening of the bed. Such process is often called “self-leveling” phenomenon. Spreading of the debris bed by the self-leveling process can take significant time, depending on the initial debris bed configuration and other parameters. There is a competition between the time scales for reaching (i) a coolable configuration of the bed, and (ii) onset of dryout and re-melting of the debris. In the previous work we have demonstrated that the rate of particulate debris spreading is determined by local gas velocity and local slope angle of the bed. In this work we develop a scaling approach and a closure for prediction of debris spreading rate based on generalization of available experimental data. We demonstrate that introduced scaling criteria are universal for particles of different

  10. Investigation of the structure of debris beds formed from fuel rods fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Duc-Hanh; Fichot, Florian; Topin, Vincent, E-mail: vincent.topin@irsn.fr

    2017-03-15

    This paper is a study of debris beds that can form in the core of a nuclear power plant under severe accident conditions. Such beds are formed of fragments of pellets and cladding remnants, as observed in the TMI-2 core. Many important issues are related with the morphology of those debris beds: are they coolable in case of water injection and how does molten corium progress through them if they are not coolable? The answers to those questions depend on the structure of the debris bed: porosity, number and arrangement of particles. In order to obtain relevant information, a numerical simulation of the formation of the debris bed is proposed. It relies on a granular approach of the type called “Contact Dynamics” to simulate the collapse of debris and their accumulation. Two different schemes of fuel pellet fragmentation are considered and simulations for different degrees of fragmentation of the pellets are performed. The results show that the number of axial cracks on fuel pellets strongly influences the final porosity of the debris bed. Porosities vary between 31% (less coolable cases) and 45% (similar to TMI-2 observations), with a most probable configuration around 41%. The specific surface of the bed is also evaluated. In the last part, a simple model is used to estimate the impact of the variation in geometry of the numeric debris beds on their flow properties. We show that the permeability and passability can vary respectively with a range of 30% and 15% depending on the number of fragment per pellet. The other benefits of the approach are finally discussed. Among them, the possibility to print 3D samples from the calculated images of debris beds appears as a promising perspective to perform experiments with realistic debris beds.

  11. Gas-cooled reactor programs: High-Temperature Gas-cooled Reactor Base-Technology Program. Annual progress report for period ending December 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Homan, F.J.; Kasten, P.R.

    1979-06-01

    Progress in HTGR studies is reported in the following areas: fission product transport and coolant impurity effects, fueled graphite development, PCRV development, structural materials, characterization and standardization of graphite, and evaluation of the pebble-bed type HTGR.

  12. Experimental studies on the coolability of packed beds. Flooding of hot dry packed beds; Experimentelle Untersuchungen zur Kuehlbarkeit von Schuettbetten. Fluten heisser, trockener Schuettungen

    Energy Technology Data Exchange (ETDEWEB)

    Leininger, S.; Kulenovic, R.; Laurien, E. [Stuttgart Univ. (Germany). Inst. fuer Kernenergetik und Energiesysteme (IKE)

    2013-07-01

    In case of a severe accident in a nuclear power plant meltdown of the reactor core can occur and form a packed bed in the lower plenum of the reactor pressure vessel (RPV) after solidification due to contact with water. The removal of after-heat and the long-term coolability is of essential interest. The efficient injection of cooling water into the packed bed has to be assured without endangering the structural integrity of the reactor pressure vessel. The experiments performed aimed to study the dry-out and the quenching (flooding) of hot dry packed beds. Two different inflow variants, bottom- and top-flooding including the variation of the starting temperature of the packed bed and the injection rate were studied. In case of bottom flooding the quenching time increases with increasing packed bed temperature and decreasing injection rate. In case of top flooding the flow pattern is more complex, in a first phase the water flows preferentially toward the RPV wall, the flow paths conduct the water downwards. The flow resistance of the packed bed increases with increasing bed temperatures. The quenching temperatures increase significantly above average.

  13. High-temperature gas-cooled reactor technology development program. Annual progress report for period ending December 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1981-08-01

    Research activities are described concerning HTGR chemistry; fueled graphite development; prestressed concrete pressure vessel development; structural materials; HTGR graphite studies; HTR core evaluation; reactor physics; shielding; application and project assessments; and HTR Core Flow Test Loop studies.

  14. HTGR Resilient Control System Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Lynne M. Stevens

    2010-09-01

    A preeminent objective for corporate and government organizations is the protection of major investments, which is attained by achieving state awareness, a comprehensive understanding of security and safety, for critical infrastructures. Given the dependence of critical infrastructure on control systems for automation, the integrity of these systems and their ability to provide owner/operators a high degree of state awareness is essential in attaining a high degree of investment protection and public acceptance. Operators as well as government are therefore burdened to ensure they have a timely understanding of the status of their plant or all plants, respectively, to ensure efficient operations and investment and public protection. “This characterization is a significant objective that must consider many aspects of instrumentation, control, and intelligent systems in order to achieve the required result. These aspects include sensory, communication, analysis, decision, and human system interfaces necessary to achieve fusion of data and presentation of results that will provide an understanding of what issues are important and why.

  15. Designing a CR Test bed

    DEFF Research Database (Denmark)

    2014-01-01

    Research on intelligent and reconfigurable wireless systems is in continuous evolution. Nevertheless, in order to fix some keystones, more and more researchers are entering the idea of research-oriented test beds. Unfortunately, it is very difficult for a wide number of research groups to start w...

  16. Laboratory rearing of bed bugs

    Science.gov (United States)

    The resurgence of bed bugs Cimex lectularius L. in the United States and worldwide has resulted in an increase in research by university, government, and industry scientists directed at the biology and control of this blood-sucking pest. A need has subsequently arisen for producing sufficient biolog...

  17. How to Find Bed Bugs

    Science.gov (United States)

    Find and correctly identify an infestation early before it becomes widespread. Look for rusty or reddish stains and pinpoint dark spots on bed sheets or mattresses, and search for bugs near the piping, seams and tags of the mattress and box spring.

  18. Impact of different discharge patterns on bed occupancy rate and bed waiting time: a simulation approach.

    Science.gov (United States)

    Zhu, Zhecheng

    2011-01-01

    Beds are one of the most important resources in a healthcare system. How to manage beds efficiently is an important indicator of the efficiency of the healthcare system. Bed management is challenging to many healthcare service providers in many aspects. In recent years, population growth and aging society impose extra pressure on bed requirement. There are usually two key performance indicators of a bed management system: bed occupancy rate and bed waiting time. In this paper, different discharge patterns and their impacts on the bed occupancy rate and bed waiting time are studied. A discrete event simulation model is constructed to evaluate the existing discharge pattern in a Singapore regional hospital using actual hospital admission and discharge transaction data. Then different discharge patterns are tested in the same context. Simulation results show that a proper discharge pattern significantly smoothes the fluctuation of bed occupancy rate and reduce the bed waiting time.

  19. 球床式高温气冷堆的余热不确定性分析%Uncertainty Analysis on Decay Heat of Pebble-bed High Temperature Gas-cooled Reactor

    Institute of Scientific and Technical Information of China (English)

    贠相羽; 郑艳华; 经荥清; 李富

    2013-01-01

    反应堆在停堆后相当长时间内仍具有较高的剩余发热是核电站的重要特性,也是核电站安全分析的关键.因此,对反应堆余热及其不确定性进行分析,对于合理设计余热排出系统、研究论证燃料元件在事故后的安全特性等均具有重要意义.本工作结合德国针对球床式高温气冷堆制定的余热计算标准,介绍了球床式高温气冷堆剩余发热及其不确定性的计算方法,并结合200 MWe球床模块式高温气冷堆示范工程(HTR-PM)的初步物理设计,对长期运行在满功率平衡堆芯状态下的反应堆停堆后的余热及其不确定性进行了计算分析,为进一步的事故分析提供依据.%The large amount of decay heat in a quite long time after reactor shutdown,which is an important characteristic of the nuclear power plants,should be considered seriously during the safety analysis.Therefore,the study on the decay heat and its uncertainty analysis play an important role in the design of decay heat removal system,as well as in the safety verification of the fuel element during the accident.In referenced to the standard of Germany entitled "Decay Heat Power in Nuclear Fuels of Hightemperature Reactors with Spherical Fuel Elements" especially for pebble-bed high temperature gas-cooled reactor (HTGR),the calculation method of decay heat and its uncertainty of pebble-bed HTGR were introduced.On the basis of the preliminary physical design of Chinese 200 MWe high temperature gas-cooled reactor pebble-bed module (HTR-PM),the decay heat and its uncertainty after reactor shutdown from long-term operation at rated power were analyzed,so as to provide a basis for further accident analysis.

  20. Pulling a patient up in bed

    Science.gov (United States)

    Moving a patient in bed ... takes at least 2 people to safely move a patient up in bed. Friction from rubbing can ... A slide sheet is the best way to prevent friction. If you do not have one, you ...

  1. EMERGING TECHNOLOGY BULLETIN: SPOUTED BED REACTOR

    Science.gov (United States)

    The Spouted Bed Reactor (SBR) technology utilizes the unique attributes of the "spouting " fluidization regime, which can provide heat transfer rates comparable to traditional fluid beds, while providing robust circulation of highly heterogeneous solids, concurrent with very agg...

  2. Find a Bed Bug Pesticide Product

    Science.gov (United States)

    Introduces the Bed Bug Product Search Tool, to help consumers find EPA-registered pesticides for bed bug infestation control. Inclusion in this database is not an endorsement. Always follow label directions carefully.

  3. Bed Bug Guidance for School Nurses

    Science.gov (United States)

    School nurses are often called upon to provide vital information to students, parents, teachers, and administrators. These tips on identifying, managing and preventing bed bugs will help you to effectively respond if bed bugs appear in your school.

  4. Videos, Webinars, Blogs Related to Bed Bugs

    Science.gov (United States)

    These tools provide practical insight on issues such as integrated pest management (IPM) for schools, bed bug bites, how carpet beetles can help, bed bugs as hitchhikers, and preventing and controlling infestations.

  5. Chinese Bedding Technology Standard under Drafting

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    National Home Textile Standardization Technology Committee(NHTSTC)set up its Bedding Branch Committee. This will promote the work of Chinese bedding technology standardization and a symbol that China step up to meet the

  6. [Historical analysis of the hospital bed].

    Science.gov (United States)

    Fajardo-Ortiz, Guillermo; Fajardo-Dolci, Germán

    2010-01-01

    Until now the bed has been the basic physical resource in hospitals. This type of furniture has served to study and treat patients, through out the centuries it has undergone changes in the materials they are made of dimensions, functionality, accessories, aesthetic, and design. The hospital bed history is not well known, there are thousands of documents about the evolution of hospitals, but not enough is known about hospital beds, a link between the past and the present. The medical, anthropological, technological, social, and economic dynamics and knowledge have produced a variety of beds in general and hospital beds in particular. From instinctive, rustic, poor and irregular "sites" that have differed in shape and size they had evolved into ergonomic equipment. The history of the hospital bed reflects the culture, techniques and human thinking. Current hospital beds include several types: for adults, for children, for labor, for intensive therapy, emergency purposes, census and non census beds etc.

  7. Spatial and Temporal Patterns of Bed Mobility Revealed Through the Use of Hydrodynamic Modeling and Motion-Sensing Radio Tagged Particles in a Large Gravel-Bed River

    Science.gov (United States)

    May, C. L.; Smith Pryor, B.; Lisle, T. E.; Lang, M. M.

    2010-12-01

    Flow conditions that initiate bedload transport, and an understanding of the spatial and temporal variability in bed mobility, provide important insight into the dynamics of riverine habitat. However, quantifying these processes at the reach scale has been elusive, especially in large river systems. Our approach coupled hydrodynamic modeling and empirical measures of bed mobility based on traditional tracers and motion-sensing radio tagged particles to determine flow conditions at initial motion and the spatial extent of bed mobility in the Trinity River of northern California. High-resolution bathymetric surveying and grain size measurements were used as input for hydrodynamic modeling. A narrow band Acoustic Doppler Profiler positioned using a Real Time Kinematic global positioning system provided separate calibration and validation data during flood events. Model-predicted Shields stress identified spatially explicit zones of differential bed mobility and indicated that a potential zone of full mobility was limited to a central core that expanded with increasing flow strength. Model-predicted zones of full mobility were well validated by patches of traditional painted rock tracer particles. In addition to traditional tracers, motion-sensing radio tagged particles were used to identify the timing of initial motion. By simultaneously measuring discharge, and modeling bed forces at that discharge, shear stress at initial motion was calculated. These calculations revealed that initial motion of bed particles varied substantially between flood events. Temporal variability in the distribution of critical shear stress suggests that the sequence of flood events is an important determinant of bed strength and, thus, resistance to motion. The combined use of high-resolution instrumentation and flow modeling revealed important insight into the importance of bed conditioning by previous floods on bed mobility.

  8. Three-dimensional simulation of liquid injection, film formation and transport, in fluidized beds

    Institute of Scientific and Technical Information of China (English)

    Paul (Pinghua) Zhao; Peter J. O'Rourke; Dale Snider

    2009-01-01

    Liquid injection, and film formation and transport in dense-phase gas-solids fluidized beds are numerically simulated in three dimensions using a collisional exchange model that is based on the mechanism that collisions cause transfer of liquid mass, momentum, and energy between particles. In the model, each of the particles is represented by a solid core and a liquid film surrounding the core. The model is incorporated in the framework of the commercial code Barracuda developed by CPFD Software. The commercial software is an advanced CFD-based computational tool where the particles are treated as discrete entities, calculated by the MP-PIC method, and tracked using the Lagrangian method.Details of the collisional liquid transfer model have been previously presented in O'Rourke, Zhao, and Snider (2009); this paper presents new capabilities and proof-testing of the collision model and a new method to better quantify the penetration length. Example calculations of a fluidized bed without liquid injection show the expected effect of collisions on the reduction of granular temperature (fluctuational kinetic energy) of the bed. When applied to liquid injection into a dense-phase fluidized bed under different conditions, the model predicts liquid penetration lengths comparable to the experiments. In addition, the simulation reveals for the first time the dynamic mixing of the liquid droplets with the bed particles and the transient distribution of the droplets inside the bed.

  9. Numerical model of characteristics of a particulate debris bed coolability with single phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Je Whan

    2008-02-15

    Designed on the basis of defense-in-depth concept, liquid metal cooled fast reactor, such as KALIMER-600 (Korea Advanced Liquid Metal Reactor) is unlikely to undergo the HCDA (hypothetical core disruptive accident). Because of its inherent safety features, most of the incidents of abnormal operation end with reactor trip and no further progression. Under a postulated, very low probable core meltdown scenario without reactor trip, however, there exists a possibility of re-criticality and vessel melting and the status of debris generated plays an important role. For this reason, the analysis on the ability of post-accident heat removal (PAHR) should be preceded. As a part of this, single phase flow coolability analysis of the particulate debris bed formed at the top of core catcher has been performed to achieve in-vessel fuel retention. The analysis is based on the Ergun equation and Macdonald's work that describe the phenomena of flow through a porous media with Hardee and Nilson's study of temperature relationship of the debris beds. The forming process of particulate debris bed is described and single phase cooling model with numerical results are presented. The analysis was conducted in the condition of three cases, inner and inner+middle and whole core meltdown case. It was proved that the inner and inner+middle core meltdown case could be cooled down with single phase flow. The whole core meltdown case will need some other management. Also, parameter sensitivity test was done.

  10. Characteristics of fluidized-packed beds

    Science.gov (United States)

    Gabor, J. D.; Mecham, W. J.

    1968-01-01

    Study of fluidized-packed bed includes investigation of heat transfer, solids-gas mixing, and elutriation characteristics. A fluidized-packed bed is a system involving the fluidization of small particles in the voids of a packed bed of larger nonfluidized particles.

  11. Fluidization quality analyzer for fluidized beds

    Science.gov (United States)

    Daw, C. Stuart; Hawk, James A.

    1995-01-01

    A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence.

  12. Bed Bug Education for School Maintenance

    Science.gov (United States)

    Henriksen, Missy

    2012-01-01

    Bed bugs are a growing problem, not only in homes and hotels, but also in schools and colleges. Facility administrators and staff need to understand the bed bug resurgence and develop best practices to deal with an infestation. In this article, the author offers tips for preventing and treating bed bugs in school and university settings.

  13. Bed Bug Education for School Maintenance

    Science.gov (United States)

    Henriksen, Missy

    2012-01-01

    Bed bugs are a growing problem, not only in homes and hotels, but also in schools and colleges. Facility administrators and staff need to understand the bed bug resurgence and develop best practices to deal with an infestation. In this article, the author offers tips for preventing and treating bed bugs in school and university settings.

  14. 21 CFR 868.5180 - Rocking bed.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rocking bed. 868.5180 Section 868.5180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5180 Rocking bed. (a) Identification. A rocking bed is a...

  15. 21 CFR 880.6070 - Bed board.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bed board. 880.6070 Section 880.6070 Food and... GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Miscellaneous Devices § 880.6070 Bed board. (a) Identification. A bed board is a device intended for medical purposes that consists...

  16. Investigation of debris bed formation, spreading and coolability

    Energy Technology Data Exchange (ETDEWEB)

    Kudinov, P.; Konovalenko, A.; Grishchenko, D.; Yakush, S.; Basso, S.; Lubchenko, N.; Karbojian, A. [Royal Institute of Technology, KTH. Div. of Nuclear Power Safety, Stockholm (Sweden)

    2013-08-15

    The work is motivated by the severe accident management strategy adopted in Nordic type BWRs. It is assumed that core melt ejected from the vessel will fragment, quench and form a coolable debris bed in a deep water pool below the vessel. In this work we consider phenomena relevant to the debris bed formation and coolability. Several DEFOR-A (Debris Bed Formation - Agglomeration) tests have been carried out with new corium melt material and a melt releasing nozzle mockup. The influence of the melt material, melt superheat, jet free fall height on the (i) faction of agglomerated debris, (ii) particle size distribution, (iii) ablation/plugging of the nozzle mockup has been addressed. Results of the DECOSIM (Debris Coolability Simulator) code validation against available COOLOCE data are presented in the report. The dependence of DHF on system pressure from COOLOCE experiments can be reproduced quite accurately if either the effective particle diameter or debris bed porosity is increased. For a cylindrical debris bed, good agreement is achieved in DECOSIM simulations for the particle diameter 0.89 mm and porosity 0.4. The results obtained are consistent with MEWA simulation where larger particle diameters and porosities were found to be necessary to reproduce the experimental data on DHF. It is instructive to note that results of DHF prediction are in better agreement with POMECO-HT data obtained for the same particles. It is concluded that further clarification of the discrepancies between different experiments and model predictions. In total 13 exploratory tests were carried out in PDS (particulate debris spreading) facility to clarify potential influence of the COOLOCE (VTT) facility heaters and TCs on particle self-leveling process. Results of the preliminary analysis suggest that there is no significant influence of the pins on self-leveling, at least for the air superficial velocities ranging from 0.17 up to 0.52 m/s. Further confirmatory tests might be needed

  17. Advanced multi-dimensional deterministic transport computational capability for safety analysis of pebble-bed reactors

    Science.gov (United States)

    Tyobeka, Bismark Mzubanzi

    A coupled neutron transport thermal-hydraulics code system with both diffusion and transport theory capabilities is presented. At the heart of the coupled code is a powerful neutronics solver, based on a neutron transport theory approach, powered by the time-dependent extension of the well known DORT code, DORT-TD. DORT-TD uses a fully implicit time integration scheme and is coupled via a general interface to the thermal-hydraulics code THERMIX-DIREKT, an HTR-specific two dimensional core thermal-hydraulics code. Feedback is accounted for by interpolating multigroup cross sections from pre-generated libraries which are structured for user specified discrete sets of thermal-hydraulic parameters e.g. fuel and moderator temperatures. The coupled code system is applied to two HTGR designs, the PBMR 400MW and the PBMR 268MW. Steady-state and several design basis transients are modeled in an effort to discern with the adequacy of using neutron diffusion theory as against the more accurate but yet computationally expensive neutron transport theory. It turns out that there are small but significant differences in the results from using either of the two theories. It is concluded that diffusion theory can be used with a higher degree of confidence in the PBMR as long as more than two energy groups are used and that the result must be checked against lower order transport solution, especially for safety analysis purposes. The end product of this thesis is a high fidelity, state-of-the-art computer code system, with multiple capabilities to analyze all PBMR safety related transients in an accurate and efficient manner.

  18. Review of acute cancer beds.

    LENUS (Irish Health Repository)

    Evans, D S

    2012-01-01

    A review of admissions to cancer services at University Hospital Galway (UHG) was undertaken to assess the appropriateness of hospital usage. All cancer specialty patients admitted from 26-28 May 2009 were reviewed (n = 82). Chi square tests, Exact tests, and One-way ANOVA were utilised to analyse key issues emerging from the data. Fifty (61%) were classified as emergencies. Twenty three (67%) occupied a designated cancer bed with 24 (30%) in outlying non-oncology wards. The mean length of stay was 29.3 days. Possible alternatives to admission were identified for 15 (19%) patients. There was no evidence of discharge planning for 50 (60%) admissions. There is considerable potential to make more appropriate utilisation of UHG for cancer patients, particularly in terms of reducing bed days and length of stay and the proportion of emergency cancer admissions, and further developing integrated systems of discharge planning.

  19. Review of acute cancer beds.

    LENUS (Irish Health Repository)

    Evans, D S

    2012-01-01

    A review of admissions to cancer services at University Hospital Galway (UHG) was undertaken to assess the appropriateness of hospital usage. All cancer specialty patients admitted from 26-28 May 2009 were reviewed (n = 82). Chi square tests, Exact tests, and One-way ANOVA were utilised to analyse key issues emerging from the data. Fifty (61%) were classified as emergencies. Twenty three (67%) occupied a designated cancer bed with 24 (30%) in outlying non-oncology wards. The mean length of stay was 29.3 days. Possible alternatives to admission were identified for 15 (19%) patients. There was no evidence of discharge planning for 50 (60%) admissions. There is considerable potential to make more appropriate utilisation of UHG for cancer patients, particularly in terms of reducing bed days and length of stay and the proportion of emergency cancer admissions, and further developing integrated systems of discharge planning.

  20. THE BAUXITES AND JELAR - BEDS

    Directory of Open Access Journals (Sweden)

    Krešimir Sakač

    1993-12-01

    Full Text Available Minor bauxite deposits and occurrences were formed in technically disturbed environments in the middle part of the Adriatic geotectonic unit in Dinarides, contemporary with the clastic Jelar-beds in the Late Lutetian time. Uneven chemical composition of these Eocene bauxites, their sporadic occurrences in developed paleorelief as well as characteristic petrographic composition of the immediate overlying rocks point out at different genetical conditions (the paper is published in Croatian.

  1. [Structure and fluidization of an internally circulating fluidized bed for FGD process].

    Science.gov (United States)

    Yang, Liuchun; Yang, Wenqi; Tong, Zhiquan

    2003-09-01

    A new internally circulating fluidized bed for FGD process was developed, and different types of top and bottom structures were employed in the experiment to find out the best fluidized bed structure. Fluidizing status, the axial distribution of solid hold-up and the fluid mechanics under cold conditions were investigated. The results indicate that the unit can realize internally circulating of a large number of solid particles which presents an core-annulus structure when the velocity of fluidizing gas was at the range of 2.5 to 5 m/s, and that the solid density in the bed is higher than that in traditional equal diameter fluidized bed, which provide the equipment with potential for application in FGD process.

  2. Agglomeration-Free Distributor for Fluidized Beds

    Science.gov (United States)

    Ouyang, F.; Sinica, A.; Levenspiel, O.

    1986-01-01

    New gas distributor for fluidized beds prevents hot particles from reacting on it and forming hard crust. In reduction of iron ore in fluidized bed, ore particles do not sinter on distributor and perhaps clog it or otherwise interfere with gas flow. Distributor also relatively cool. In fluidized-bed production of silicon, inflowing silane does not decompose until within bed of hot silicon particles and deposits on them. Plates of spiral distributor arranged to direct incoming gas into spiral flow. Turbulence in flow reduces frequency of contact between fluidized-bed particles and distributor.

  3. Studies on IPTV over IMS test bed

    Directory of Open Access Journals (Sweden)

    K. Sundara Raja Raja Perumal

    2012-09-01

    Full Text Available IMS (IP Multimedia Subsystem is an architectural frame work which allows the convergence of Wireless, Wire line networks and internet thereby serving the use of a global platform for the delivery of IP multimedia applications. Thus IMS leads in the greater support of Next Generation Networks (NGN. The cause for IMS a high level technology’s design and origin is mainly for the 3rd Generation Partnership Projects (3GPP. The intension of the design and origin of such a subsystem is to enable the service providers to create and deliver value added services to the users on heterogeneous network. IMS is all about sending data (voice, video, files etc over an instrument using absolutely any kind of networks. The system has been configured to the real IP of 127.0.0.1 using the open source tool of OpenIMSCore. IMS has been configured between the hosts using OPEN IMS CORE test bed on an Open Source platform and initiate the calls between several IMS clients and its registration was evaluated. The traffic parameters of SIP IMS parameter has been verified using Wireshark network analyzer.

  4. FLUIDIZATION OF FINE POWDERS IN FLUIDIZED BEDS WITH AN UPWARD OR A DOWNWARD AIR JET

    Institute of Scientific and Technical Information of China (English)

    Ruoyu Hong; Jianmin Ding; Hongzhong Li

    2005-01-01

    The hydrodynamic behavior of fine powders in jet-fluidized beds was studied numerically and experimentally. The starting point of numerical simulation was the generalized Navier-Stokes (N-S) equations for the gas and solids phases. The κ-εturbulence model was used for high-speed gas jets in fluidized beds. Computation shows that a suitable turbulence model is necessary to obtain agreement between the simulation and literature experimental data for a high-speed gas jet. The model was applied to simulating the fluidization of fine powders in fluidized beds with an upward or a downward air jet. An empirical cohesion model was obtained by correlating the cohesive force between fine particles using a cohetester. The cohesion model was embedded into the two-fluid model to simulate the fluidization of fine powders in two-dimensional (2-D) beds. To study the fluidization behavior of fine and cohesive powders with a downward jet,experiments were performed in a 2-D bed. Agreement between the computed time-averaged porosity and measured data was obtained. With an upward jet in the bed center, the measured and computed porosities show a dilute central core, especially at very high jet velocities. Based on our experiments and computations, a downward jet located inside the bed is recommended to achieve better mixing and contacting of gas and solids.

  5. Relationship Between Faults Oriented Parallel and Oblique to Bedding in Neogene Massive Siliceous Mudstones at The Horonobe Underground Research Laboratory, Japan

    Science.gov (United States)

    Hayano, Akira; Ishii, Eiichi

    2016-10-01

    This study investigates the mechanical relationship between bedding-parallel and bedding-oblique faults in a Neogene massive siliceous mudstone at the site of the Horonobe Underground Research Laboratory (URL) in Hokkaido, Japan, on the basis of observations of drill-core recovered from pilot boreholes and fracture mapping on shaft and gallery walls. Four bedding-parallel faults with visible fault gouge, named respectively the MM Fault, the Last MM Fault, the S1 Fault, and the S2 Fault (stratigraphically, from the highest to the lowest), were observed in two pilot boreholes (PB-V01 and SAB-1). The distribution of the bedding-parallel faults at 350 m depth in the Horonobe URL indicates that these faults are spread over at least several tens of meters in parallel along a bedding plane. The observation that the bedding-oblique fault displaces the Last MM fault is consistent with the previous interpretation that the bedding- oblique faults formed after the bedding-parallel faults. In addition, the bedding-parallel faults terminate near the MM and S1 faults, indicating that the bedding-parallel faults with visible fault gouge act to terminate the propagation of younger bedding-oblique faults. In particular, the MM and S1 faults, which have a relatively thick fault gouge, appear to have had a stronger control on the propagation of bedding-oblique faults than did the Last MM fault, which has a relatively thin fault gouge.

  6. Equilibrium bed-concentration of nonuniform sediment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Knowledge of the equilibrium bed-concentration is vital to mathematical modeling of the river-bed deformation associated with suspended load but previous investigations only dealt with the reference concentration of uniform sediment because of difficulties in observation of the bed-concentration. This work is a first attempt to develop a theoretical formula for the equilibrium bed-concentration of any fraction of nonuniform sediment defined at the bed-surface. The formula is based on a stochastic-mechanistic model for the exchange of nonuniform sediment near the bed, and described as a function of incipient motion probability, non-ceasing probability, pick-up probability, and the ratio of the average single-step continuous motion time to static time. Comparison of bed-concentration calculated from the proposed formula with the measured data showed satisfactory agreement, indicating the present formula can be used for solving the differential equation governing the motion of suspended load.

  7. Dual-core antiresonant hollow core fibers.

    Science.gov (United States)

    Liu, Xuesong; Fan, Zhongwei; Shi, Zhaohui; Ma, Yunfeng; Yu, Jin; Zhang, Jing

    2016-07-25

    In this work, dual-core antiresonant hollow core fibers (AR-HCFs) are numerically demonstrated, based on our knowledge, for the first time. Two fiber structures are proposed. One is a composite of two single-core nested nodeless AR-HCFs, exhibiting low confinement loss and a circular mode profile in each core. The other has a relatively simple structure, with a whole elliptical outer jacket, presenting a uniform and wide transmission band. The modal couplings of the dual-core AR-HCFs rely on a unique mechanism that transfers power through the air. The core separation and the gap between the two cores influence the modal coupling strength. With proper designs, both of the dual-core fibers can have low phase birefringence and short modal coupling lengths of several centimeters.

  8. Effective medium theory expressions for the effective diffusion in chromatographic beds filled with porous, non-porous and porous-shell particles and cylinders. Part II: Numerical verification and quantitative effect of solid core on expected B-term band broadening.

    Science.gov (United States)

    Deridder, Sander; Desmet, Gert

    2011-01-07

    The results of a numerical simulation study of the diffusion and retention in fully porous spheres and cylinders are compared with some of the high order accuracy analytical solutions for the effective diffusion coefficient that have been derived from the effective medium theory (EMT) theory in part I of the present study. A variety of different ordered (spheres and cylinders) and disordered (cylinders) packings arrangements has been considered. The agreement between simulations and theory was always excellent, lying within the (very tight) accuracy limits of the simulations over the full range of retention factor and diffusion constant values that is practically relevant for most LC applications. Subsequently filling up the spheres and cylinders with a central solid core, while keeping the same packing geometry and the same mobile phase (same thermodynamic retention equilibrium), it was found that the core induces an additional obstruction which reduces the effective intra-particle diffusion coefficient exactly with a factor γ(part)=2/(2+ρ³) for spherical particles and γ(part)=1/(1+ρ²) for cylinders (ρ is the ratio of the core to the particle diameter, ρ=d(core)/d(part)). These expressions hold independently of the packing geometry, the value of the diffusion coefficients and the equilibrium constant or the size of the core. The expressions also imply that, if considering equal mobile phase conditions, the presence of the solid core will never reduce the particle contribution to the B-term band broadening with more than 33% (50% in case of cylindrical pillars). Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Hospital Bed Type, the Electronic Medical Record, and Safe Bed Elevation in the Intensive Care Setting.

    Science.gov (United States)

    Fitch, Zachary W; Duquaine, Damon; Ohkuma, Rika; Schneider, Eric B; Whitman, Glenn J R

    2016-01-01

    In mechanically ventilated patients, head of bed (HOB) elevation above 30° decreases the risk of ventilator-associated pneumonia. The research team studied (a) compliance with proper HOB elevation in their cardiac surgical intensive care unit, (b) the accuracy of HOB angles recorded in the electronic medical record (EMR), and (c) the effect of bed type on (a) and (b). Nurses were polled to discover how HOB angles were measured in practice. HOB angles were compliant in 80% of observations. Compliance was more frequent in beds with side-of-bed angle indicators (SBI) than beds with under-bed angle indicators (UBI; 88% vs 77%, P = .04). Charting in the EMR was accurate in 50% of SBI bed observations but only 20% of UBI bed observations (P bed type. Bedside indicators are underutilized. © The Author(s) 2014.

  10. The Safety of Hospital Beds: Ingress, Egress, and In-Bed Mobility.

    Science.gov (United States)

    Morse, Janice M; Gervais, Pierre; Pooler, Charlotte; Merryweather, Andrew; Doig, Alexa K; Bloswick, Donald

    2015-01-01

    To explore the safety of the standard and the low hospital bed, we report on a microanalysis of 15 patients' ability to ingress, move about the bed, and egress. The 15 participants were purposefully selected with various disabilities. Bed conditions were randomized with side rails up or down and one low bed with side rails down. We explored the patients' use of the side rails, bed height, ability to lift their legs onto the mattress, and ability to turn, egress, and walk back to the chair. The standard bed was too high for some participants, both for ingress and egress. Side rails were used by most participants when entering, turning in bed, and exiting. We recommend that side rails be reconsidered as a means to facilitate in-bed movement, ingress, and egress. Furthermore, single deck height settings for all patients are not optimal. Low beds as a safety measure must be re-evaluated.

  11. Modular Pebble-Bed Reactor Project: Laboratory-Directed Research and Development Program FY 2002 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Petti, David Andrew; Dolan, Thomas James; Miller, Gregory Kent; Moore, Richard Leroy; Terry, William Knox; Ougouag, Abderrafi Mohammed-El-Ami; Oh, Chang H; Gougar, Hans D

    2002-11-01

    This report documents the results of our research in FY-02 on pebble-bed reactor technology under our Laboratory Directed Research and Development (LDRD) project entitled the Modular Pebble-Bed Reactor. The MPBR is an advanced reactor concept that can meet the energy and environmental needs of future generations under DOE’s Generation IV initiative. Our work is focused in three areas: neutronics, core design and fuel cycle; reactor safety and thermal hydraulics; and fuel performance.

  12. Modular Pebble-Bed Reactor Project: Laboratory-Directed Research and Development Program FY 2002 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Petti, David Andrew; Dolan, Thomas James; Miller, Gregory Kent; Moore, Richard Leroy; Terry, William Knox; Ougouag, Abderrafi Mohammed-El-Ami; Oh, Chang H; Gougar, Hans D

    2002-11-01

    This report documents the results of our research in FY-02 on pebble-bed reactor technology under our Laboratory Directed Research and Development (LDRD) project entitled the Modular Pebble-Bed Reactor. The MPBR is an advanced reactor concept that can meet the energy and environmental needs of future generations under DOE’s Generation IV initiative. Our work is focused in three areas: neutronics, core design and fuel cycle; reactor safety and thermal hydraulics; and fuel performance.

  13. Pellet bed reactor concept for nuclear electric propulsion

    Science.gov (United States)

    El-Genk, Mohamed S.; Morley, Nicholas J.; Juhasz, Albert

    1993-01-01

    For Nuclear Electric Propulsion (NEP) applications, gas cooled nuclear reactors with dynamic energy conversion systems offer high specific power and low total mass. This paper describes the Pellet Bed Reactor (PeBR) concept for potential NEP missions to Mars. The helium cooled, 75-80 MWt PeBR, consists of a single annular fuel region filled with a randomly packed bed of spherical fuel pellets, is designed for multiple starts, and offers unique safety and operation features. Each fuel pellet, about 8-10 mm in diameter, is composed of hundreds of TRISO type fuel microspheres embedded in a graphite matrix for a full retention of fission products. To eliminate the likelihood of a single-point failure, the annular core of the PeBR is divided into three 120° sectors. Each sector is self contained and separate and capable of operating and being cooled on its own and in cooperation with either one or two other sectors. Each sector is coupled to a separate, 5 MWe Closed Brayton Cycle (CBC) energy conversion unit and is subcritical for safe handling and launching. In the event of a failure of the cooling system of a core sector, the reactor power level may be reduced, allowing adjacent sectors to convect the heat away using their own cooling system, thus maintaining reactor operation. Also, due to the absence of an internal core structure in the PeBR core, fueling of the reactor can easily be performed either at the launch facility or in orbit, and refueling can be accomplished in orbit as needed to extend the power system lifetime

  14. CHARACTERISTICS OF SELF-LEVELING BEHAVIOR OF DEBRIS BEDS IN A SERIES OF EXPERIMENTS

    Directory of Open Access Journals (Sweden)

    SONGBAI CHENG

    2013-06-01

    Full Text Available During a hypothetical core-disruptive accident (CDA in a sodium-cooled fast reactor (SFR, degraded core materials can form roughly conically-shaped debris beds over the core-support structure and/or in the lower inlet plenum of the reactor vessel from rapid quenching and fragmentation of the core material pool. However, coolant boiling may ultimately lead to leveling of the debris bed, which is crucial to the relocation of the molten core and heat-removal capability of the debris bed. To clarify the mechanisms underlying this self-leveling behavior, a large number of experiments were performed within a variety of conditions in recent years, under the constructive collaboration between the Japan Atomic Energy Agency (JAEA and Kyushu University (Japan. The present contribution synthesizes and gives detailed comparative analyses of those experiments. Effects of various experimental parameters that may have potential influence on the leveling process, such as boiling mode, particle size, particle density, particle shape, bubbling rate, water depth and column geometry, were investigated, thus giving a large palette of favorable data for the better understanding of CDAs, and improved verifications of computer models developed in advanced fast reactor safety analysis codes.

  15. The Berlin emissivity database (BED)

    Science.gov (United States)

    Maturilli, A.; Helbert, J.; Moroz, L.

    2008-03-01

    Remote-sensing infrared spectroscopy is the principal field of investigation for planetary surfaces composition. Past, present and future missions to the solar system bodies include in their payload, instruments measuring the emerging radiation in the infrared range. Apart from measuring the reflected radiance, more and more spacecrafts are equipped with instruments measuring directly the emitted radiation from the planetary surface. The emitted radiation is not only a function of the composition of the material but also of its texture and especially the grain size distribution. For the interpretation of the measured data an emissivity spectral library of planetary analogue materials in grain size fractions appropriate for planetary surfaces is needed. The Berlin emissivity database (BED) presented here is focused on relatively fine-grained size separates, providing thereby a realistic basis for the interpretation of thermal emission spectra of planetary regoliths. The BED is therefore complimentary to existing thermal emission libraries, like the ASU library for example. BED currently contains emissivity spectra of plagioclase and potassium feldspars, low Ca and high Ca pyroxenes, olivine, elemental sulfur, Martian analogue minerals and volcanic soils, and a lunar highland soil sample measured in the wavelength range from 7 to 22 μm as a function of particle size. For each sample we measured the spectra of four particle size separates ranging from <25 to 250 μm. The device we used is built at DLR (Berlin) and is coupled to a Fourier-transform infrared spectrometer Bruker IFS 88 purged with dry air and equipped with a nitrogen-cooled MCT detector. All spectra were acquired with a spectral resolution of 4 cm -1. We are currently working on upgrading our emissivity facility. A new spectrometer (Bruker VERTEX 80 V) and new detectors will allow us to measure the emissivity of samples in the wavelength range from 1 to 50 μm in a vacuum environment. This will be

  16. Combustion Model FOr Staged Circulating Fluidized Bed BOiler

    Institute of Scientific and Technical Information of China (English)

    FandJianhua; LuQinggang; 等

    1997-01-01

    A mathematical model for atmospheric staged circulating fluidized bed combustion,which takes fluid dynamics,combustion,heat transfer,pollutants formation and retention,into account was developed in the institute of Engineering Thermophysics(IET)recently.The model of gas solid flow at the bottom of the combustor was treated by the two-phase theory of fluidized bed and in the upper region as a core-annulus flow structure.The chemical species CO,CO2,H2,H2O,CH4,O2 and N2 were considered in the reaction process.The mathematical model consisted of sub-modeles of fluid namics,coal heterogeneous and gas homogeneous chemical reactions.heat transfer,particle fragmentation and attrition,mass and energy balance tec.The developed code was applied to simulate an operating staged circulating fluidized bed combustion boiler of early design and the results were in good agreement with the operating data.The main submodels and simulation results are given in this paoper.

  17. Numerical Analysis of Characteristics of a Particulate Debris Bed Coolability with Single Phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jew-han; Chang, Soon-heung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Cho, Chung-ho; Lee, Yong-bum [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-05-15

    Designed on the basis of defense-in-depth concept, liquid metal cooled reactor, such as KALIMER-600 is unlikely to undergo the hypothetical core disruptive accident (HCDA). However in case of accident, there exists a possibility of re-criticality and vessel melting when core melt-down occurs. For this reason, the analysis on the ability of post-accident heat removal (PAHR) should be preceded. As a part of this, single phase flow coolability analysis of the particulate debris bed formed at the top of core catcher has been performed to achieve in-vessel fuel retention. The forming process of particulate debris bed is described and single phase cooling model with numerical results are presented.

  18. Designing a CR Test bed

    DEFF Research Database (Denmark)

    2014-01-01

    with their own set up, since the potential costs and efforts could not pay back in term of expected research results. Software Defined Radio solutions offer an easy way to communication researchers for the development of customized research test beds. While several hardware products are commercially available......, the software is most of the times open source and ready to use for third party users. Even though the software solution developers claim complete easiness in the development of custom applications, in reality there are a number of practical hardware and software issues that research groups need to face, before...... inspiration to researchers on how to possibly build their own customized systems....

  19. [Special beds. Pulmonary therapy system].

    Science.gov (United States)

    Calixto Rodríguez, Joaquín; Rodríguez Martínez, Xavier; Marín i Vivó, Gemma; Paunellas Albert, Josep

    2008-10-01

    To be bedridden reduces one's capacity to move and produces muscular debility that affects the respiratory system leading to a decreased effectiveness in expectoration, the ability to spit up sputum. The pulmonary therapy system integrated in a bed is the result of applying motorized elements to the articulation points of the bad in order to achieve safe positions at therapeutic angles, which improve the breathing-perfusion (blood flow) relationship. This system also makes it possible to apply vibration waves to the patient which favor the elimination of bronchial-pulmonary secretions, the rehabilitation of the bedridden patient and decrease the work load for nursing personnel.

  20. Animal MRI Core

    Data.gov (United States)

    Federal Laboratory Consortium — The Animal Magnetic Resonance Imaging (MRI) Core develops and optimizes MRI methods for cardiovascular imaging of mice and rats. The Core provides imaging expertise,...

  1. Fluidized-Bed Coating with Sodium Sulfate and PVA-TiO2, 1. Review and Agglomeration Regime Maps

    DEFF Research Database (Denmark)

    Hede, Peter Dybdahl; Bach, Poul; Jensen, Anker Degn

    2009-01-01

    This paper, and two associated papers [Hede, P. D.; Jensen, A. D.; Bach, P. Ind. Eng. Chem. Res. 2009, 48, 1905 and 1914], address the fluid-bed coating of placebo enzyme granules (i.e., sodium sulfate cores, with a size range of 400-500 mu m) using two types of coatings: sodium sulfate and PVA-TiO......2. The coating experiments were conducted in a medium-scale top-spray MP-1 fluid bed, and many rheological experiments were performed on the coating formulations to support the interpretation of the fluid-bed coating results. In this first part of the study, a thorough introduction to the inorganic...

  2. Suicide following an infestation of bed bugs.

    Science.gov (United States)

    Burrows, Stephanie; Perron, Stéphane; Susser, Stephanie

    2013-01-01

    Male, 62. Bipolar disorder. Bordeline personality disorder. - Bed bug infestation. Psychiatry. Unusual clinical course. In the past decade, bed bug infestations have been increasingly common in high income countries. Psychological consequences of these infestations are rarely examined in the scientific literature. We present a case, based on a coroner's investigation report, of a woman with previous psychiatric morbidity who jumped to her death following repeated bed bug infestations in her apartment. Our case report shows that the bed bug infestations were the likely trigger for the onset a negative psychological state that ultimately led to suicide. Given the recent surge in infestations, rapid action needs to be taken not only in an attempt to control and eradicate the bed bugs but also to adequately care for those infested by bed bugs.

  3. Classifying bed inclination using pressure images.

    Science.gov (United States)

    Baran Pouyan, M; Ostadabbas, S; Nourani, M; Pompeo, M

    2014-01-01

    Pressure ulcer is one of the most prevalent problems for bed-bound patients in hospitals and nursing homes. Pressure ulcers are painful for patients and costly for healthcare systems. Accurate in-bed posture analysis can significantly help in preventing pressure ulcers. Specifically, bed inclination (back angle) is a factor contributing to pressure ulcer development. In this paper, an efficient methodology is proposed to classify bed inclination. Our approach uses pressure values collected from a commercial pressure mat system. Then, by applying a number of image processing and machine learning techniques, the approximate degree of bed is estimated and classified. The proposed algorithm was tested on 15 subjects with various sizes and weights. The experimental results indicate that our method predicts bed inclination in three classes with 80.3% average accuracy.

  4. Packed fluidized bed blanket for fusion reactor

    Science.gov (United States)

    Chi, John W. H.

    1984-01-01

    A packed fluidized bed blanket for a fusion reactor providing for efficient radiation absorption for energy recovery, efficient neutron absorption for nuclear transformations, ease of blanket removal, processing and replacement, and on-line fueling/refueling. The blanket of the reactor contains a bed of stationary particles during reactor operation, cooled by a radial flow of coolant. During fueling/refueling, an axial flow is introduced into the bed in stages at various axial locations to fluidize the bed. When desired, the fluidization flow can be used to remove particles from the blanket.

  5. Burning of spent fuel of an accelerator-driven modular HTGR in sub-critical condition%乏燃料在加速器驱动的次临界模块式HTGR中的燃烧

    Institute of Scientific and Technical Information of China (English)

    经荥清; 杨永伟; 常鸿; 吴宗鑫; 古玉祥

    2002-01-01

    环状模块式高温气冷堆(HTGR)采用包覆颗粒燃料,其乏燃料经过一段时间的堆外冷却后,可以再利用.研究了350 MW环状模块式HTGR乏燃料在加速器驱动的次临界堆中燃烧的物理可行性.给出了功率为30 MW次临界堆概念设计,利用MCNP程序模拟中子在次临界堆内的输运过程,利用ORIGEN2程序进行燃耗计算.结果表明: 加速器驱动的次临界气冷堆具有可靠的次临界度和低的功率密度,用于燃烧350 MW环状模块式HTGR乏燃料, 从能源利用的角度考虑,可以获得约20%的额外收益.

  6. CERTS Microgrid Laboratory Test Bed

    Energy Technology Data Exchange (ETDEWEB)

    Eto, Joe; Lasseter, Robert; Schenkman, Ben; Stevens, John; Klapp, Dave; Volkommer, Harry; Linton, Ed; Hurtado, Hector; Roy, Jean

    2009-06-18

    The objective of the CERTS Microgrid Test Bed project was to enhance the ease of integrating energy sources into a microgrid. The project accomplished this objective by developing and demonstrating three advanced techniques, collectively referred to as the CERTS Microgrid concept, that significantly reduce the level of custom field engineering needed to operate microgrids consisting of generating sources less than 100kW. The techniques comprising the CERTS Microgrid concept are: 1) a method for effecting automatic and seamless transitions between grid-connected and islanded modes of operation, islanding the microgrid's load from a disturbance, thereby maintaining a higher level of service, without impacting the integrity of the utility's electrical power grid; 2) an approach to electrical protection within a limited source microgrid that does not depend on high fault currents; and 3) a method for microgrid control that achieves voltage and frequency stability under islanded conditions without requiring high-speed communications between sources. These techniques were demonstrated at a full-scale test bed built near Columbus, Ohio and operated by American Electric Power. The testing fully confirmed earlier research that had been conducted initially through analytical simulations, then through laboratory emulations,and finally through factory acceptance testing of individual microgrid components. The islanding and resychronization method met all Institute of Electrical and Electronics Engineers Standard 1547 and power quality requirements. The electrical protection system was able to distinguish between normal and faulted operation. The controls were found to be robust under all conditions, including difficult motor starts and high impedance faults. The results from these tests are expected to lead to additional testing of enhancements to the basic techniques at the test bed to improve the business case for microgrid technologies, as well to field

  7. C. elegans BED domain transcription factor BED-3 controls lineage-specific cell proliferation during organogenesis

    OpenAIRE

    Inoue, Takao; Sternberg, Paul W.

    2010-01-01

    The control of cell division is critical to organogenesis, but how this control is achieved is not fully understood. We found that mutations in bed-3, encoding a BED Zn-finger domain transcription factor, confer a phenotype where a specific set of cell divisions during vulval organogenesis is lost. Unlike general cell cycle regulators in Caenorhabditis elegans, the function of bed-3 is restricted to specific lineages. Transcriptional reporters suggest that bed-3 is expressed in a limited numb...

  8. As thick as three in a bed.

    Science.gov (United States)

    Scheidegger, Christoph

    2016-07-01

    During the evolution of the lichen symbiosis, shifts from one main type of photobiont to another were infrequent (Miadlikowska et al. ) but some remarkable transitions from green algal to diazotrophic cyanobacterial photobionts are known from unrelated fungal clades within the ascomycetes. Cyanobacterial, including tripartite, associations (green algal and cyanobacterial photobionts in one lichen individual) facilitate these holobionts to live as C- and N-autotrophs. Tripartite lichens are among the most productive lichens, which provide N-fertilization to forest ecosystems under oceanic climates (Peltigerales) or deliver low, but ecologically significant N-input into subarctic and alpine soil communities (Lecanorales, Agyriales). In this issue of Molecular Ecology, Schneider et al. (2016) mapped morphometric data against an eight-locus fungal phylogeny across a transition of photobiont interactions from green algal to a tripartite association and used a phylogenetic comparative framework to explore the role of nitrogen-fixing cyanobacteria in size differences in the Trapelia-Placopsis clade (Agyriales). Within the group of tripartite species, the volume of cyanobacteria-containing structures (cephalodia) correlates with thallus thickness in both phylogenetic generalized least squares and phylogenetic generalized linear mixed-effects analyses, and the fruiting body core volume increased ninefold. The authors conclude that cyanobacterial symbiosis appears to have enabled lichens to overcome size constraints in oligotrophic environments such as rock surfaces. The Trapelia-Placopsis clade analyzed by Schneider et al. (2016) is an exciting example of interactions between ecology, phylogeny and lichen biology including development - from thin crustose green algal microlichens to thick placodioid, tripartite macrolichens: as thick as three in a bed (Scott ).

  9. Fluidized-bed combustion of gasification residue

    Energy Technology Data Exchange (ETDEWEB)

    Kudjoi, A.; Heinolainen, A.; Hippinen, I.; Lu, Y. [Helsinki University of Technology, Espoo (Finland). Lab. of Energy Economics and Power Plant Engineering

    1998-12-31

    Hybrid combined cycle processes have been presented as possibilities for power generation in the future. In the processes based on partial gasification of coal, the solid materials removed from a gasifier (i.e. fly ash and bed char) contain unburned fuel, which is burned either in an atmospheric or a pressurised fluidised-bed. Pressurised fluidised-bed (PFB) combustion of gasification residues were studied experimentally by Helsinki University of Technology. The gasification residues, i.e. cyclone fines and bed chars, came from pilot scale PFB gasification tests of bituminous coals. The combustion efficiency was high in cyclone fines combustion. The calcium sulphide oxidised effectively to calcium sulphate in the combustion of cyclone fines. In bed char combustion the residual sulphide contents in solids after combustion were still relatively high. In general, sulphur dioxide emissions in residue combustion were low. The recarbonation of calcium oxide was observed in bed char combustion. Fuel-N conversion to NO{sub x} during bed char combustion and in most of the test runs with cyclone fines was higher than in bituminous coal combustion. In bed char combustion the conversion was significantly higher than in cyclone fines combustion. NO{sub x} emissions increased with increasing excess air for both residues, as was expected. In bed char combustion the highest NO{sub x} emissions were measured at higher pressure. Calculated mass reactivity values of equal particle size of all bed chars studied had similar trends with burnout. The biggest particles had the lowest reactivity values throughout the combustion, while reactivity for finer particles was at considerably higher level and sharply increases with burnout. In the constant combustion conditions used in the tests, no significant differences were observed in rate-controlling mechanisms for bed char fractions studied. 25 refs., 13 figs., 15 tab.

  10. Flue gas desulfurization by rotating beds

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, N.; Keyvani, M.; Coskundeniz, A.

    1992-01-01

    The operating and mass transfer characteristics of rotating foam metal beds were studied to determine the potential for flue gas desulfurization. This is a final technical report on the work supported by DOE [number sign]FG22-87-PC79924. The report is divided into two sections, Part 1 deals primarily with the operating characteristics of rotating beds, and Part 2 covers the mass transfer characteristics of S0[sub 2] absorption in water-lime slurries. Rotating foam metal beds are in essence packed towers operated in high gravitational fields. The foam metal bed is in the form of a cylindrical donut, or torus, and is rotated to produced the high centrifugal forces. The liquid phase enters the bed at the inner surface of the torus and is pulled by the field through the bed. Gas flows countercurrent to the liquid. The bed packing can have a very large specific surface areas and not flood. Possible benefits include much smaller height of a transfer unit resulting in smaller equipment and supporting structures, reduced solvent inventory, faster response with improved process control, reduced pressure drop, and shorter startup and shut-down times. This work is concerned broadly with the operating characteristics of rotating beds, the objectives being to (1) determine the pressure drop through the rotating bed; (2) determine the power required to operate the beds, (3) investigate the residence time distribution of the liquid phase in the beds; and (4) determine the mass transfer coefficients of S0[sub 2] absorption. Three packings of differing specific surface areas were studied, with areas ranging from 656 to 2952 m[sub 2]/m[sub 3]. Liquid flow rates to 36 kg/s*m[sub 2], gas flow rate to 2.2 kg/s*m[sub 2], and gravitational fields to 300 g were covered in this study.

  11. CERTS Microgrid Laboratory Test Bed

    Energy Technology Data Exchange (ETDEWEB)

    ETO, J.; LASSETER, R.; SCHENKMAN, B.; STEVENS, J.; KLAPP, D.; VOLKOMMER, H.; LINTON, E.; HURTADO, H.; ROY, J.

    2010-06-08

    The objective of the CERTS Microgrid Test Bed project was to enhance the ease of integrating energy sources into a microgrid. The project accomplished this objective by developing and demonstrating three advanced techniques, collectively referred to as the CERTS Microgrid concept, that significantly reduce the level of custom field engineering needed to operate microgrids consisting of generating sources less than 100kW. The techniques comprising the CERTS Microgrid concept are: 1 a method for effecting automatic and seamless transitions between grid-connected and islanded modes of operation, islanding the microgrid's load from a disturbance, thereby maintaining a higher level of service, without impacting the integrity of the utility's electrical power grid; 2 an approach to electrical protection within a limited source microgrid that does not depend on high fault currents; and 3 a method for microgrid control that achieves voltage and frequency stability under islanded conditions without requiring high-speed communications between sources.

  12. Metabolic Resistance in Bed Bugs

    Directory of Open Access Journals (Sweden)

    Omprakash Mittapalli

    2011-03-01

    Full Text Available Blood-feeding insects have evolved resistance to various insecticides (organochlorines, pyrethroids, carbamates, etc. through gene mutations and increased metabolism. Bed bugs (Cimex lectularius are hematophagous ectoparasites that are poised to become one of the major pests in households throughout the United States. Currently, C. lectularius has attained a high global impact status due to its sudden and rampant resurgence. Resistance to pesticides is one factor implicated in this phenomenon. Although much emphasis has been placed on target sensitivity, little to no knowledge is available on the role of key metabolic players (e.g., cytochrome P450s and glutathione S-transferases towards pesticide resistance in C. lectularius. In this review, we discuss different modes of resistance (target sensitivity, penetration resistance, behavioral resistance, and metabolic resistance with more emphasis on metabolic resistance.

  13. Metabolic Resistance in Bed Bugs.

    Science.gov (United States)

    Mamidala, Praveen; Jones, Susan C; Mittapalli, Omprakash

    2011-03-18

    Blood-feeding insects have evolved resistance to various insecticides (organochlorines, pyrethroids, carbamates, etc.) through gene mutations and increased metabolism. Bed bugs (Cimex lectularius) are hematophagous ectoparasites that are poised to become one of the major pests in households throughout the United States. Currently, C. lectularius has attained a high global impact status due to its sudden and rampant resurgence. Resistance to pesticides is one factor implicated in this phenomenon. Although much emphasis has been placed on target sensitivity, little to no knowledge is available on the role of key metabolic players (e.g., cytochrome P450s and glutathione S-transferases) towards pesticide resistance in C. lectularius. In this review, we discuss different modes of resistance (target sensitivity, penetration resistance, behavioral resistance, and metabolic resistance) with more emphasis on metabolic resistance.

  14. Fluidized bed coal combustion reactor

    Science.gov (United States)

    Moynihan, P. I.; Young, D. L. (Inventor)

    1981-01-01

    A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

  15. Physician-patient communication in single-bedded versus four-bedded hospital rooms.

    NARCIS (Netherlands)

    Glind, I. van de; Dulmen, S. van; Goossensen, A.

    2008-01-01

    Objective: To examine whether physician-patient communication in multi-bedded rooms differs from communication in single rooms during ward rounds. Methods: Ward rounds in single bedded patient rooms and ward rounds in four bedded rooms were audiotaped and analyzed with an adapted version of MIARS.

  16. Pulsed atmospheric fluidized bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    1989-11-01

    In order to verify the technical feasibility of the MTCI Pulsed Atmospheric Fluidized Bed Combustor technology, a laboratory-scale system was designed, built and tested. Important aspects of the operational and performance parameters of the system were established experimentally. A considerable amount of the effort was invested in the initial task of constructing an AFBC that would represent a reasonable baseline against which the performance of the PAFBC could be compared. A summary comparison of the performance and emissions data from the MTCI 2 ft {times} 2 ft facility (AFBC and PAFBC modes) with those from conventional BFBC (taller freeboard and recycle operation) and circulating fluidized bed combustion (CFBC) units is given in Table ES-1. The comparison is for typical high-volatile bituminous coals and sorbents of average reactivity. The values indicated for BFBC and CFBC were based on published information. The AFBC unit that was designed to act as a baseline for the comparison was indeed representative of the larger units even at the smaller scale for which it was designed. The PAFBC mode exhibited superior performance in relation to the AFBC mode. The higher combustion efficiency translates into reduced coal consumption and lower system operating cost; the improvement in sulfur capture implies less sorbent requirement and waste generation and in turn lower operating cost; lower NO{sub x} and CO emissions mean ease of site permitting; and greater steam-generation rate translates into less heat exchange surface area and reduced capital cost. Also, the PAFBC performance generally surpasses those of conventional BFBC, is comparable to CFBC in combustion and NO{sub x} emissions, and is better than CFBC in sulfur capture and CO emissions even at the scaled-down size used for the experimental feasibility tests.

  17. Effect of Faulting on Ordovician Carbonate Buried-Hill Reservoir Beds in Hetianhe Gas Field,Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    Lü Xiuxiang; Bai Zhongkai; Li Jianjiao; Wang Weiguang; Fu Hui; Wang Qinghua

    2008-01-01

    Ordovician carbonate buried-hill reservoir beds in the Hetianhe (和田河) gas field,located in the Mazhatage (玛扎塔格) structural belt on the southern margin of the Bachu (巴楚) faulted uplift,southwestern Tarim basin,were studied.Based on field survey,core and slice observation,the general characteristics of carbonate buried-hill reservoir beds and specifically Ordovician carbonate buried-hill reservoir beds in the Hetianhe gas field were discussed.The karst zone of the reservoir beds in Hetianhe gas field was divided into superficial karst zone,vertical infiltration karst zone,lower subsurface flow karst zone,and deep sluggish flow zone from top to bottom.The effects of faulting on Ordovician carbonate buried-hill reservoir beds in the Hetianhe gas field were obvious.The faulting intensified the karstification and increased the depth of denudation.Faulting and subsequent fracture growth modified the reservoir beds and improved the physical property and quality of the reservoir beds.Moreover,faulting enhanced the development of the dissolution holes and fractures and increased the thickness of the effective reservoir beds.Meanwhile,faulting made the high porosity-permeability carbonate belts,which created conditions for the hydrocarbon accumulation,develop near the fault zone.

  18. Geologic, geotechnical, and geophysical properties of core from the Acme Fire-Pit-1 drill hole, Sheridan County, Wyoming

    Science.gov (United States)

    Collins, Donley S.

    1983-01-01

    A preliminary core study from the Acme Fire-Pit-1 drill hole, Sheridan County, Wyoming, revealed that the upper portion of the core had been baked by a fire confined to the underlying Monarch coal bed. The baked (clinkered) sediment above the Monarch coal bed was determined to have higher point-load strength values (greater than 2 MPa) than the sediment under the burned coal

  19. Effective Thermal Conductivity of Adsorbent Packed Beds

    Science.gov (United States)

    Mori, Hideo; Hamamoto, Yoshinori; Yoshida, Suguru

    The effective thermal conductivity of adsorbent packed beds of granular zeolite 13X and granular silica gel A in the presence of stagnant steam or air was measured under different conditions of the adsorbent bed temperature, particle size and filler-gas pressure. The measured effective thermal conductivity showed to become smaller with decreasing particle size or decreasing pressure, but it was nearly independent of the bed temperature. When steam was the filler-gas, the rise in the thermal conductivity of the adsorbent particles due to steam adsorption led to the increase in the effective thermal conductivity of the bed, and this effect was not negligible at high steam pressure for the bed of large particle size. It was found that both the predictions of the effective thermal conductivity by the Hayashi et al.'s model and the Bauer-Schlünder model generally agreed well with the measurements, by considering the particle thermal conductivity rise due to steam adsorption. The thermal conductivity of a consolidated bed of granular zeolite 13X was also measured, and it was found to be much larger than that of the packed bed especially at lower pressure. The above prediction models underestimated the effective thermal conductivity of the consolidated bed.

  20. Gruppebaseret behandling af BED - et faseopdelt behandlingstilbud

    DEFF Research Database (Denmark)

    Laust, Jakob; Lau, Marianne Engelbrecht; Waaddegaard, Mette

    2015-01-01

    konsekvenser. BED blev i 2013 optaget i DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) som en selvstændig diagnose og BED forventes medtaget i den forestående revision af det internationale diagnose system, ICD-11. Sundhedsstyrelsen gav på denne baggrund satspuljemidler til erfaringsopsamling...

  1. Particle Pressures in Fluidized Beds. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction): they impart to the bed. So rather than directly measure the particle pressure, we inferred the values of the elasticity from measurements of instability growth in liquid beds the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined)and then working backwards to determine the unknown coefficients, including the elasticity.

  2. Hipparions of the Laetolil Beds, Tanzania

    NARCIS (Netherlands)

    Hooijer, D.A.

    1979-01-01

    The Laetolil Beds in Tanzania, 20-30 miles south of Olduvai Gorge, have been extensively sampled by parties under the leadership of Mrs. Dr. Mary D. Leakey, who very kindly sent me Hipparion material collected in 1974, 1975, and 1976. In a restudy of proboscidean material from these beds described

  3. Particle pressures in fluidized beds. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction), they impart to the bed. So rather than directly measure the particle pressure, the authors inferred the values of the elasticity from measurements of instability growth in liquid beds; the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined) and then working backwards to determine the unknown coefficients, including the elasticity.

  4. Bed-levelling experiments with suspended load

    NARCIS (Netherlands)

    Talmon, A.M.; De Graaff, J.

    1991-01-01

    Bed-levelling experiments are conducted in a straight laboratory channel. The experiments involve a significant fraction of suspended sediment transport. The purpose of the experiments is to provide data for modelling of the direction of sediment transport on a transverse sloping alluvial river bed,

  5. Nonlinear dynamical characteristics of bed load motion

    Institute of Scientific and Technical Information of China (English)

    BAI; Yuchuan; XU; Haijue; XU; Dong

    2006-01-01

    Bed forms of various kinds that evolve naturally on the bottom of sandy coasts and rivers are a result of the kinematics of bed load transport. Based on the group motion of particles in the bed load within the bottom layer, a study on the nonlinear dynamics of bed load transport is presented in this paper. It is found that some development stages, such as the initiation, the equilibrium sediment transport, and the transition from a smooth bed to sand dunes, can be accounted for by different states in the nonlinear system of the bed load transport. It is verified by comparison with experimental data reported by Laboratoire Nationae D'Hydraulique, Chatou, France, that the evolution from a smooth bed to sand dunes is determined by mutation in the bed load transport. This paper presents results that may offer theoretical explanations to the experimental observations. It is also an attempt to apply the state-of-the-art nonlinear science to the classical sediment transport mechanics.

  6. Bed-levelling experiments with suspended load

    NARCIS (Netherlands)

    Talmon, A.M.; De Graaff, J.

    1991-01-01

    Bed-levelling experiments are conducted in a straight laboratory channel. The experiments involve a significant fraction of suspended sediment transport. The purpose of the experiments is to provide data for modelling of the direction of sediment transport on a transverse sloping alluvial river bed,

  7. Print a Bed Bug Card - (Single Cards)

    Science.gov (United States)

    Two sets of business-card-sized lists of tips for recognizing bed bugs and the signs of an infestation, including a photo of bed bugs to assist identification. One card is for general use around home or office, the other for travelers.

  8. Bed bugs: clinical relevance and control options.

    Science.gov (United States)

    Doggett, Stephen L; Dwyer, Dominic E; Peñas, Pablo F; Russell, Richard C

    2012-01-01

    Since the late 1990s, bed bugs of the species Cimex lectularius and Cimex hemipterus have undergone a worldwide resurgence. These bed bugs are blood-sucking insects that readily bite humans. Cutaneous reactions may occur and can start out as small macular lesions that can develop into distinctive wheals of around 5 cm in diameter, which are accompanied by intense itching. Occasionally, bullous eruptions may result. If bed bugs are numerous, the patient can present with widespread urticaria or eythematous rashes. Often, bites occur in lines along the limbs. Over 40 pathogens have been detected in bed bugs, but there is no definitive evidence that they transmit any disease-causing organisms to humans. Anemia may result when bed bugs are numerous, and their allergens can trigger asthmatic reactions. The misuse of chemicals and other technologies for controlling bed bugs has the potential to have a deleterious impact on human health, while the insect itself can be the cause of significant psychological trauma. The control of bed bugs is challenging and should encompass a multidisciplinary approach utilizing nonchemical means of control and the judicious use of insecticides. For accommodation providers, risk management procedures should be implemented to reduce the potential of bed bug infestations.

  9. Prevalence, Knowledge, and Concern About Bed Bugs.

    Science.gov (United States)

    Kaylor, Mary Beth; Wenning, Paul; Eddy, Christopher

    2015-01-01

    Recent research suggests that the resurgence of bed bugs in the U.S. has occurred at an alarming rate. Assumptions have been made that socioeconomic status is not associated with the prevalence of bed bug infestations. Little information is available at the local level, however, about the prevalence of bed bugs in private homes. The authors' pilot study aimed to identify prevalence, knowledge, and concern about bed bugs in one higher income village in Ohio utilizing survey methodology. Responses from 96 individuals who completed the Prevalence, Knowledge, and Concern About Bed Bugs survey were utilized for analysis. The majority of the sample respondents were white and 95% reported that they owned their residence. Only 6% knew someone with bed bugs. Additionally, 52% reported they were somewhat concerned about bed bugs. About 46% reported that they had changed their behavior. For a higher income area, the prevalence was dissimilar to the rate reported in the general public (about 20%). This suggests that bed bugs may be an environmental issue effecting low-income populations disproportionately. Further research is needed in areas of differing socioeconomic levels.

  10. Hipparions of the Laetolil Beds, Tanzania

    NARCIS (Netherlands)

    Hooijer, D.A.

    1979-01-01

    The Laetolil Beds in Tanzania, 20-30 miles south of Olduvai Gorge, have been extensively sampled by parties under the leadership of Mrs. Dr. Mary D. Leakey, who very kindly sent me Hipparion material collected in 1974, 1975, and 1976. In a restudy of proboscidean material from these beds described b

  11. International Standardization of Bed Rest Standard Measures

    Science.gov (United States)

    Cromwell, Ronita L.

    2010-01-01

    This slide presentation gives an overview of the standardization of bed rest measures. The International Countermeasures Working Group attempted to define and agree internationally on standard measurements for spaceflight based bed rest studies. The group identified the experts amongst several stakeholder agencys. It included information on exercise, muscle, neurological, psychological, bone and cardiovascular measures.

  12. Determination of true bed thickness using folded bed model and borehole data

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S.S.; Velasquillo-Martinez, L.G.; Grajales-Nishimura, J.M.; Murillo-Muneton, G. [Inst. Mexicano del Petroleo, Mexico City (Mexico); Garcia-Hernandez, J. [Petroleos Mexicanos Exploracion y Produccion, Tamaulipas (Mexico); Nieto-Samaniego, A.F. [Nacional Autonoma de Mexico Univ., Veracruz (Mexico). Centro de Geociencias

    2007-11-15

    The actual thickness of a given formation perpendicular to the bedding plane is known as the true bed thickness. Petroleum engineers rely on information regarding true bed thickness, particularly in dipping beds and in deviated holes because reservoir volume and isochore maps depend on these properties and not on the measured thickness. True bed thickness can be estimated from information gathered from well logs such as the dipmeter and borehole images. However, when deviations and dips exceed 10 degrees, corrections are needed. In this paper, a folded bed model was proposed to calculate the true bed thickness in the subsurface utilizing well log data. The value of true bed thickness (t) was shown to depend on the angle and the direction of the dip of the measured formation, as well as the drift angle and azimuth of the borehole. A case study from the Cantarell oil field in the southern Gulf of Mexico, offshore Campeche, was used to test the folded bed method. The model was shown to yield more uniform spatial change of the values of t, compared to the monoclinal bed model that often overestimates the average value of t. The maximum relative deviation of t from the monoclinal bed model reached 22.3 per cent and the maximum absolute deviation of t reached 34.5 m. The key factors that influence the values of t were found to be the bed dip, the dip difference between the top and base of the bed and the deviated angle of the well. The folded bed model yielded fewer changed values of the true bed thickness. 10 refs., 2 tabs., 9 figs.

  13. k-core covers and the core

    NARCIS (Netherlands)

    Sanchez-Rodriguez, E.; Borm, Peter; Estevez-Fernandez, A.; Fiestras-Janeiro, G.; Mosquera, M.A.

    2015-01-01

    This paper extends the notion of individual minimal rights for a transferable utility game (TU-game) to coalitional minimal rights using minimal balanced families of a specific type, thus defining a corresponding minimal rights game. It is shown that the core of a TU-game coincides with the core of

  14. Academic Rigor: The Core of the Core

    Science.gov (United States)

    Brunner, Judy

    2013-01-01

    Some educators see the Common Core State Standards as reason for stress, most recognize the positive possibilities associated with them and are willing to make the professional commitment to implementing them so that academic rigor for all students will increase. But business leaders, parents, and the authors of the Common Core are not the only…

  15. k-core covers and the core

    NARCIS (Netherlands)

    Sanchez-Rodriguez, E.; Borm, Peter; Estevez-Fernandez, A.; Fiestras-Janeiro, G.; Mosquera, M.A.

    This paper extends the notion of individual minimal rights for a transferable utility game (TU-game) to coalitional minimal rights using minimal balanced families of a specific type, thus defining a corresponding minimal rights game. It is shown that the core of a TU-game coincides with the core of

  16. Peering inside the granular bed: illuminating feedbacks between bed-load transport and bed-structure evolution

    Science.gov (United States)

    Houssais, M.; Jerolmack, D. J.; Martin, R. L.

    2013-12-01

    The threshold of motion is perhaps the most important quantity to determine for understanding rates of bed load transport, however it is a moving target. Decades of research show that it changes in space and in time within a river, and is highly variable among different systems; however, these differences are not mechanistically understood. Recent researchers have proposed that the critical Shields stress is strongly dependent on the local configuration of the sediment bed [Frey and Church, 2011]. Critical Shields stress has been observed to change following sediment-transporting flood events in natural rivers [e.g., Turowski et al., 2011], while small-scale laboratory experiments have produced declining bed load transport rates associated with slow bed compaction [Charru et al., 2004]. However, no direct measurements have been made of the evolving bed structure under bed load transport, so the connection between granular controls and the threshold of motion remains uncertain. A perspective we adopt is that granular effects determine the critical Shields stress, while the fluid supplies a distribution of driving stresses. In order to isolate the granular effect, we undertake laminar bed load transport experiments using plastic beads sheared by a viscous oil in a small, annular flume. The fluid and beads are refractive index matched, and the fluid impregnated with a fluorescing powder. When illuminated with a planar laser sheet, we are able to image slices of the granular bed while also tracking the overlying sediment transport. We present the first results showing how bed load transport influences granular packing, and how changes in packing influence the threshold of motion to feed back on bed load transport rates. This effect may account for much of the variability observed in the threshold of motion in natural streams, and by extension offers a plausible explanation for hysteresis in bed load transport rates observed during floods. Charru, F., H. Mouilleron, and

  17. Does Bedding Affect the Airway and Allergy?

    Directory of Open Access Journals (Sweden)

    J Crane

    2011-03-01

    Full Text Available Various cross-sectional and longitudinal studies have suggested that synthetic bedding is associated with asthma, allergic rhinitis and eczema while feather bedding seems to be protective. Synthetic bedding items have higher house dust mite allergen levels than feather bedding items. This is possibly the mechanism involved although fungal and bacterial proinflammatory compounds and volatile organic compounds may play a role. In this review we present and discuss the epidemiological evidence and suggest possible mechanisms. Primary intervention studies are required to show whether feather bedding is protective for the development of childhood asthma and allergic diseases while secondary intervention studies are required to potentially reduce symptoms and medication use in subjects with established disease.

  18. Incipient motion of gravel and coal beds

    Indian Academy of Sciences (India)

    Subhasish Dey; Uddaraju V Raju

    2002-10-01

    An experimental study on incipient motion of gravel and coal beds under unidirectional steady-uniform flow is presented. Experiments were carried out in a flume with various sizes of gravel and coal samples. The critical bed shear stresses for the experimental runs determined using side-wall correction show considerable disagreement with the standard curves. The characteristic parameters affecting the incipient motion of particles in rough-turbulent regime, identified based on physical reasoning and dimensional analysis, are the Shields parameter, particle Froude number, non-dimensional particle diameter and non-dimensional flow depth. Equations of critical bed shear stress for the initial movement of gravel and coal beds were obtained using experimental data. The method of application of critical bed shear stress equations is also mentioned.

  19. Bed bugs: they are back! The role of the school nurse in bed bug management.

    Science.gov (United States)

    Sciscione, Patricia

    2012-09-01

    Recently there has been a resurgence of bed bugs in all facets of our society. Bed bugs have even been found in schools, causing unnecessary exclusion of students and unfounded hysteria. School nurses are again called upon to be front-line sources of information to quell the hysteria and confusion related to this unsavory condition. By arming themselves with the best evidence regarding proper identification of bed bugs and their bites and information about integrated prevention measures to control transmission of infestations, school nurses can contribute to the control and management of bed bugs and aid in the overall battle against this "new and improved" invasion of the bed bugs.

  20. Spatially resolved measurement of rock core porosity.

    Science.gov (United States)

    Marica, F; Chen, Q; Hamilton, A; Hall, C; Al, T; Balcom, B J

    2006-01-01

    Density weighted, centric scan, Conical SPRITE MRI techniques are applied in the current work for local porosity measurements in fluid saturated porous media. The methodology is tested on a series of sandstone core samples. These samples vary in both porosity and degree of local heterogeneity due to bedding plane structure. The MRI porosity measurement is in good agreement with traditional gravimetric measurements of porosity. Spatially resolved porosity measurements reveal significant porosity variation in some samples. This novel MRI technique should have applications to the characterization of local porosity in a wide variety of porous media.

  1. Innovative Bed Load Measurement System for Large Alpine Gravel-Bed Rivers

    Science.gov (United States)

    Seitz, H.; Habersack, H. M.

    2009-04-01

    The aim of the work is to figure out the bed load transport processes using direct and surrogate measurement methods for the free flowing reach of the Drau River and its most important tributary Isel River, both large Alpine gravel-bed rivers, situated in the south western part of Austria. There are some techniques for bed load measurements in natural streams; we used collecting moving particles and indirectly determining transport intensity at the study sites. Former measurements in the study reach were performed also using mobile bed load samplers and fixed bed load samplers. Individually they all are adequate bed load measurement instruments - used in combination they are complementing one another, whereas each applied separately leads to specific deficits. The investigation payed special attention on results out of the geophone installations, whereas steel plate vibrations (the plates are mounted on top of concrete structures even with the river bed surface) caused by bed load particles with a diameter larger than about 20 mm are inducing a signal into the geophones. The signal above a defined threshold voltage than is recorded in a computer system as the sum of impacts during one minute intervals. The spatio-temporal distribution of the transported bed load material, its amount and the transport processes itself could be figured out for the first time out of continuous data collection since 2006 for large alpine gravel-bed rivers. Before building up the gauging stations there were no continuous recordings of bed load transport processes in large alpine rivers over their entire cross section, hence the investigation promises a better process understanding and the possibility to determine bed load transport rates and a rough approximation of the grain size distributions of the transported bed load material under different flow conditions. A relation between detected geophone records, the flow discharge and direct bed load sampling methods (Large Helley Smith

  2. On different regime relations between bed load transport and bed topography

    Science.gov (United States)

    Zhang, L.; Ma, H.; Fu, X.; Duan, J. G.

    2016-12-01

    Bed load transport is determined by the effective part of the total shear stress subtracting the form drag that arises from bed topography. Wang et al. (2004) quantified the overall topographic roughness of the channel bed with the parameter Sp and claimed that the increasing Sp corresponds with increasing flow resistance and decreasing bed load transport rate due to increasing form drag and decreasing skin friction. However, the flume experiments for non-uniform sediment transport on steep slope at the University of Arizona show opposite results that bed load transport increases with Sp. We investigate the physical reason of the contrasting results for the full understanding of the different regimes between bed load transport and bed topography. We develop the energy conveyance equation for water flow and bed load transport and apply it to the development of the equilibrium relation between bed load transport and energy dissipation due to the form drag. The energy theory for bed load transport shows that since our flume experiments achieved the equilibrium transport state with water and sediment circulating supplying, the bed topography Sp is determined by the flow and sediment grain size, and the bed load transport is positively related to the energy dissipation rate which is thus positively related to Sp. However, in the field experiment of Wang et al. (2004), at first, the referenced Sp is determined by the most recent significant flood whereas the bed load transport is always below the transport capacity with insufficient sediment supply. After one-time sediment feed, the bed load transport rapidly varies from ephemeral full capacity state to sediment starving state. In this process, the removal of relative fine sediment results in the rapid increment of Sp from the instant equilibrium state to the referenced Sp whereas the coarsen bed leads to decrement of bed load transport. Eventually, the sediment starving state results in the increasing Sp and decreasing

  3. Hydrogeochemistry and coal-associated bacterial populations from a methanogenic coal bed

    Science.gov (United States)

    Barnhart, Elliott P.; Weeks, Edwin P.; Jones, Elizabeth J.P.; Ritter, Daniel J.; McIntosh, Jennifer C.; Clark, Arthur C.; Ruppert, Leslie F.; Cunningham, Alfred B.; Vinson, David S.; Orem, William H.; Fields, Matthew W.

    2016-01-01

    Biogenic coalbed methane (CBM), a microbially-generated source of natural gas trapped within coal beds, is an important energy resource in many countries. Specific bacterial populations and enzymes involved in coal degradation, the potential rate-limiting step of CBM formation, are relatively unknown. The U.S. Geological Survey (USGS) has established a field site, (Birney test site), in an undeveloped area of the Powder River Basin (PRB), with four wells completed in the Flowers-Goodale coal bed, one in the overlying sandstone formation, and four in overlying and underlying coal beds (Knoblach, Nance, and Terret). The nine wells were positioned to characterize the hydraulic conductivity of the Flowers-Goodale coal bed and were selectively cored to investigate the hydrogeochemistry and microbiology associated with CBM production at the Birney test site. Aquifer-test results indicated the Flowers-Goodale coal bed, in a zone from about 112 to 120 m below land surface at the test site, had very low hydraulic conductivity (0.005 m/d) compared to other PRB coal beds examined. Consistent with microbial methanogenesis, groundwater in the coal bed and overlying sandstone contain dissolved methane (46 mg/L average) with low δ13C values (−67‰ average), high alkalinity values (22 meq/kg average), relatively positive δ13C-DIC values (4‰ average), and no detectable higher chain hydrocarbons, NO3−, or SO42−. Bioassay methane production was greatest at the upper interface of the Flowers-Goodale coal bed near the overlying sandstone. Pyrotag analysis identified Aeribacillus as a dominant in situbacterial community member in the coal near the sandstone and statistical analysis indicated Actinobacteria predominated coal core samples compared to claystone or sandstone cores. These bacteria, which previously have been correlated with hydrocarbon-containing environments such as oil reservoirs, have demonstrated the ability to produce biosurfactants to break down

  4. Numerical simulations on self-leveling behaviors with cylindrical debris bed

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Liancheng, E-mail: Liancheng.guo@kit.edu [Institute for Nuclear and Energy Technologies (IKET), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Morita, Koji, E-mail: morita@nucl.kyushu-u.ac.jp [Faculty of Engineering, Kyushu University, 2-3-7, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Tobita, Yoshiharu, E-mail: tobita.yoshiharu@jaea.go.jp [Fast Reactor Safety Technology Development Department, Japan Atomic Energy Agency, 4002 Narita, O-arai, Ibaraki 311-1393 (Japan)

    2017-04-15

    Highlights: • A 3D coupled method was developed by combining DEM with the multi-fluid model of SIMMER-IV code. • The method was validated by performing numerical simulations on a series of experiments with cylindrical particle bed. • Reasonable agreement can demonstrate the applicability of the method in reproducing the self-leveling behavior. • Sensitivity analysis on some model parameters was performed to assess their impacts. - Abstract: The postulated core disruptive accidents (CDAs) are regarded as particular difficulties in the safety analysis of liquid-metal fast reactors (LMFRs). In the CDAs, core debris may settle on the core-support structure and form conic bed mounds. Then debris bed can be levelled by the heat convection and vaporization of surrounding coolant sodium, which is named “self-leveling behavior”. The self-leveling behavior is a crucial issue in the safety analysis, due to its significant effect on the relocation of molten core and heat-removal capability of the debris bed. Considering its complicate multiphase mechanism, a comprehensive computational tool is needed to reasonably simulate transient particle behavior as well as thermal-hydraulic phenomenon of surrounding fluid phases. The SIMMER program is a successful computer code initially developed as an advanced tool for CDA analysis of LMFRs. It is a multi-velocity-field, multiphase, multicomponent, Eulerian, fluid dynamics code coupled with a fuel-pin model and a space- and energy-dependent neutron kinetics model. Until now, the code has been successfully applied in numerical simulations for reproducing key thermal-hydraulic phenomena involved in CDAs as well as performing reactor safety assessment. However, strong interactions between massive solid particles as well as particle characteristics in multiphase flows were not taken into consideration in its fluid-dynamics models. To solve this problem, a new method is developed by combining the discrete element method (DEM

  5. Modeling of sulfur oxide removal in circulating fluidized bed absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Mao, D.; Edwards, J.R.; Kuznetsov, A.V. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Mechanical and Aerospace Engineering; Srivastava, R. [U.S. Environmental Protection Agency, Research Triangle Park, NC (United States). Air Pollution Prevention and Control Division

    2002-07-01

    This paper presents a model to simulate a circulating fluidized bed absorber (CFBA) that combines flow, mixing, and reaction through residence time distribution (RTD). These parameters are often overlooked in existing simulation models. In addition, the paper presents a newly developed gas-solid reaction model for sulphur dioxide removal by limestone. For the reaction model that considers RTD inside the core and annulus regions of CFBA, the macrochemical reaction is simulated according to microchemical reaction dynamics. The proposed model can predict sulphur dioxide and limestone distributions inside the CFBA and calculate how much limestone is needed to remove an appropriate amount of sulphur dioxide. Sulphur dioxide concentration at the outlet of the CFBA decreases as the distance of the CFBA increases from the bottom of the core region. Limestone concentration varies only very slightly in the core region, suggesting that limestone in the CFBA is efficiently utilized to remove sulphur oxide. Sulphur dioxide partial pressure at the exit of the CFBA decreases as fresh limestone increases at the inlet to the CFBA. 16 refs., 8 figs.

  6. CERTS Microgrid Laboratory Test Bed

    Energy Technology Data Exchange (ETDEWEB)

    Lasseter, R. H.; Eto, J. H.; Schenkman, B.; Stevens, J.; Volkmmer, H.; Klapp, D.; Linton, E.; Hurtado, H.; Roy, J.

    2010-06-08

    CERTS Microgrid concept captures the emerging potential of distributed generation using a system approach. CERTS views generation and associated loads as a subsystem or a 'microgrid'. The sources can operate in parallel to the grid or can operate in island, providing UPS services. The system can disconnect from the utility during large events (i.e. faults, voltage collapses), but may also intentionally disconnect when the quality of power from the grid falls below certain standards. CERTS Microgrid concepts were demonstrated at a full-scale test bed built near Columbus, Ohio and operated by American Electric Power. The testing fully confirmed earlier research that had been conducted initially through analytical simulations, then through laboratory emulations, and finally through factory acceptance testing of individual microgrid components. The islanding and resynchronization method met all Institute of Electrical and Electronics Engineers Standard 1547 and power quality requirements. The electrical protection system was able to distinguish between normal and faulted operation. The controls were found to be robust under all conditions, including difficult motor starts and high impedance faults.

  7. Mix bed type desalting device

    Energy Technology Data Exchange (ETDEWEB)

    Hanaoka, Shuichi; Shiozawa, Yoshihiro; Kazama, Seiichi

    1998-12-18

    The present invention provides a condensate desalting device of a BWR type reactor capable of preventing degradation of ion exchange resins by water containing oxidative materials such as hydrogen peroxide thereby keeping reactor water at high purity. Namely, a mixed bed type desalting device comprises a desalting tower for removing impurities in water by ion exchange resins and a regeneration device for cleaning/regenerating the ion exchange resins. Means for loading iron cruds into water is disposed in the desalting tower. With such a constitution, oxidative materials such as hydrogen peroxide react with the iron cruds thereby enabling to suppress oxidative reaction during ion exchange. Since passage or cleaning/regeneration of water is conducted while loading the iron cruds between ion exchange resin particles and on the surface layer of an ion exchange resin layer by using the above-mentioned reaction, degradation of ion exchange performance of the ion exchange resins by hydrogen peroxide can be prevented upon condensate cleaning operation or resin cleaning/regeneration. As a result, degradation of quality of reactor water can be suppressed. (I.S.)

  8. Modeling nitrate removal in a denitrification bed.

    Science.gov (United States)

    Ghane, Ehsan; Fausey, Norman R; Brown, Larry C

    2015-03-15

    Denitrification beds are promoted to reduce nitrate load in agricultural subsurface drainage water to alleviate the adverse environmental effects associated with nitrate pollution of surface water. In this system, drainage water flows through a trench filled with a carbon media where nitrate is transformed into nitrogen gas under anaerobic conditions. The main objectives of this study were to model a denitrification bed treating drainage water and evaluate its adverse greenhouse gas emissions. Field experiments were conducted at an existing denitrification bed. Evaluations showed very low greenhouse gas emissions (mean N2O emission of 0.12 μg N m(-2) min(-1)) from the denitrification bed surface. Field experiments indicated that nitrate removal rate was described by Michaelis-Menten kinetics with the Michaelis-Menten constant of 7.2 mg N L(-1). We developed a novel denitrification bed model based on the governing equations for water flow and nitrate removal kinetics. The model evaluation statistics showed satisfactory prediction of bed outflow nitrate concentration during subsurface drainage flow. The model can be used to design denitrification beds with efficient nitrate removal which in turn leads to enhanced drainage water quality.

  9. Factors Associated With Infant Bed-Sharing

    Science.gov (United States)

    Heere, Megan; Moughan, Beth; Alfonsi, Joseph; Rodriguez, Jennifer; Aronoff, Stephen

    2017-01-01

    Objective: Bed-sharing is associated with sudden infant death syndrome and accidental suffocation and strangulation in bed. The purpose of this study was to identify risk factors for newborn bed-sharing. Methods: Postpartum mothers from a university maternity service were contacted by phone to complete a survey. Demographic and environmental data were collected; newborn bed-sharing and sleep environment were self-reported. Results: A total of 1261 mothers completed surveys; bed-sharing was reported by 79 mothers (6.3%). Multivariate logistic regression identified referral to a nurse (odds ratio [OR] = 10; 95% confidence interval [CI] = 4.5-30) and sleep location “other” than a crib, bassinet, or Pack and Play (OR = 7.1; 95% CI = 1.9-25.9) as factors associated with an increased risk of bed-sharing; formula feeding (OR = 0.4; 95% CI = 0.20-0.77) and crib sleeping (OR = 0.49; 95% CI = 0.26-0.86) reduced this risk. Conclusion: Infants with no identifiable places to sleep, significant health issues, and who are breastfed are more likely to bed-share. Interventional studies should be directed at these factors. PMID:28229101

  10. Heat and Mass Transfer Enforcement of Vibrating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    ChuZhide; YangJunhong; 等

    1994-01-01

    This paper briefly introduces the development of vibrating fluidized bed at home and abroad,elaborates the vibration properties of vibrating fluidized bed.the fluidizing velocity and pressure drop of the bed layer,it also deduces the non-steady state drying dynamic equations of vibrating fluidized bed,analyzes main factors which influence the drying rate and inquires into drying rules of fixed bed and vibrating fluidized bed.

  11. Experimental and theoretical study of large scale debris bed reflood in the PEARL facility

    Energy Technology Data Exchange (ETDEWEB)

    Chikhi, Nourdine, E-mail: nourdine.chikhi@irsn.fr; Fichot, F.

    2017-02-15

    Highlights: • Five reflooding tests have been carried out with an experimental bed, 500 mm in height and 500 mm in diameter, made of 4 mm stainless steel balls. • For the first time, such a large bed was heated practically homogenously. • The quench front velocity was determined according to thermocouple measurements inside the bed. • An analytical model, assuming a quasi-steady progression of the quench front, allows to predict the conversion ratio in most cases. • It appears that the efficiency of cooling can be increased only up to a certain limit when increasing the inlet water flow rate. - Abstract: During a severe accident in a nuclear power plant, the degradation of fuel rods and melting of materials lead to the accumulation of core materials, which are commonly, called “debris beds”. To stop core degradation and avoid the reactor vessel rupture, the main accident management procedure consists in injecting water. In the case of debris bed, the reflooding models used for Loss of Coolant Accident are not applicable. The IRSN has launched an experimental program on debris bed reflooding to develop new models and to validate severe accident codes. The PEARL facility has been designed to perform, for the first time, the reflooding of large scale debris bed (Ø540 mm, h = 500 mm and 500 kg of steel debris) in a pressurized containment. The bed is heated by means of an induction system. A specific instrumentation has been developed to measure the debris bed temperature, pressure drop inside the bed and the steam flow rate during the reflooding. In this paper, the results of the first integral reflooding tests performed in the PEARL facility at atmospheric pressure up to 700 °C are presented. Focus is made on the quench front propagation and on the steam flow rate during reflooding. The effect of water injection flow rate, debris initial temperature and residual power are also discussed. Finally, an analytical model providing the steam flow rate and

  12. Comodules over semiperfect corings

    CERN Document Server

    Caenepeel, S

    2011-01-01

    We discuss when the Rat functor associated to a coring satisfying the left $\\alpha$-condition is exact. We study the category of comodules over a semiperfect coring. We characterize semiperfect corings over artinian rings and over qF-rings.

  13. Coring Sample Acquisition Tool

    Science.gov (United States)

    Haddad, Nicolas E.; Murray, Saben D.; Walkemeyer, Phillip E.; Badescu, Mircea; Sherrit, Stewart; Bao, Xiaoqi; Kriechbaum, Kristopher L.; Richardson, Megan; Klein, Kerry J.

    2012-01-01

    A sample acquisition tool (SAT) has been developed that can be used autonomously to sample drill and capture rock cores. The tool is designed to accommodate core transfer using a sample tube to the IMSAH (integrated Mars sample acquisition and handling) SHEC (sample handling, encapsulation, and containerization) without ever touching the pristine core sample in the transfer process.

  14. CFD Analysis of Core Bypass Phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Richard W. Johnson; Hiroyuki Sato; Richard R. Schultz

    2010-03-01

    The U.S. Department of Energy is exploring the potential for the VHTR which will be either of a prismatic or a pebble-bed type. One important design consideration for the reactor core of a prismatic VHTR is coolant bypass flow which occurs in the interstitial regions between fuel blocks. Such gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The existence of the gaps induces a flow bias in the fuel blocks and results in unexpected increase of maximum fuel temperature. Traditionally, simplified methods such as flow network calculations employing experimental correlations are used to estimate flow and temperature distributions in the core design. However, the distribution of temperature in the fuel pins and graphite blocks as well as coolant outlet temperatures are strongly coupled with the local heat generation rate within fuel blocks which is not uniformly distributed in the core. Hence, it is crucial to establish mechanistic based methods which can be applied to the reactor core thermal hydraulic design and safety analysis. Computational Fluid Dynamics (CFD) codes, which have a capability of local physics based simulation, are widely used in various industrial fields. This study investigates core bypass flow phenomena with the assistance of commercial CFD codes and establishes a baseline for evaluation methods. A one-twelfth sector of the hexagonal block surface is modeled and extruded down to whole core length of 10.704m. The computational domain is divided vertically with an upper reflector, a fuel section and a lower reflector. Each side of the sector grid can be set as a symmetry boundary

  15. CFD Analysis of Core Bypass Phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Richard W. Johnson; Hiroyuki Sato; Richard R. Schultz

    2009-11-01

    The U.S. Department of Energy is exploring the potential for the VHTR which will be either of a prismatic or a pebble-bed type. One important design consideration for the reactor core of a prismatic VHTR is coolant bypass flow which occurs in the interstitial regions between fuel blocks. Such gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The existence of the gaps induces a flow bias in the fuel blocks and results in unexpected increase of maximum fuel temperature. Traditionally, simplified methods such as flow network calculations employing experimental correlations are used to estimate flow and temperature distributions in the core design. However, the distribution of temperature in the fuel pins and graphite blocks as well as coolant outlet temperatures are strongly coupled with the local heat generation rate within fuel blocks which is not uniformly distributed in the core. Hence, it is crucial to establish mechanistic based methods which can be applied to the reactor core thermal hydraulic design and safety analysis. Computational Fluid Dynamics (CFD) codes, which have a capability of local physics based simulation, are widely used in various industrial fields. This study investigates core bypass flow phenomena with the assistance of commercial CFD codes and establishes a baseline for evaluation methods. A one-twelfth sector of the hexagonal block surface is modeled and extruded down to whole core length of 10.704m. The computational domain is divided vertically with an upper reflector, a fuel section and a lower reflector. Each side of the one-twelfth grid can be set as a symmetry boundary

  16. Gas-turbine HTGR materials screening test program. Quarterly progress report, July 1, 1976--September 30, 1976. [IN 100; IN 713; MM004; M21; IN 738; RENE 100; MoTZM; Hastelloy X; Inconel 617; MA 753; IN 519, Inconel 706; Inconel 718; A286; 316 SS; Incoloy 800

    Energy Technology Data Exchange (ETDEWEB)

    Rosenwasser, S.N.; Johnson, W.R.

    1976-09-30

    The duration of controlled-impurity creep-screening tests and unstressed aging tests has reached 10,000 hr. Creep and weight change data from testing up to 9,000 hr and results from post-test metallurgical evaluations of several recently returned 3,000-hr specimens, including alloys IN519 and MoTZM, are presented. Preliminary materials requirements for key GT-HTGR 850/sup 0/C (1562/sup 0/F) reactor outlet temperature reference design components are documented.

  17. Free running droplets on packed powder beds

    Science.gov (United States)

    Whitby, Catherine P.; Bian, Xun; Sedev, Rossen

    2013-06-01

    We observed that water drops placed on horizontal beds of fine molybdenite particles move freely over the bed surface for about 1 second. The drops collect an irregular coating of unevenly distributed particles as they bounce and roll. We manipulated the distance that the drops travel, and hence the area of the droplet surface coated with particles, by varying the water surface tension and the kinetic energy of the initial droplet impact on the bed surface. Our results highlight the role of contact angle hysteresis in particle encapsulation of liquid drops.

  18. Fluidised-bed combustion of gasification residue

    Energy Technology Data Exchange (ETDEWEB)

    Korpela, T.; Kudjoi, A.; Hippinen, I.; Heinolainen, A.; Suominen, M.; Lu Yong [Helsinki Univ. of Technology (Finland). Lab of Energy Economics and Power Plant Engineering

    1996-12-01

    Partial gasification processes have been presented as possibilities for future power production. In the processes, the solid materials removed from a gasifier (i.e. fly ash and bed material) contain unburnt fuel and the fuel conversion is increased by burning this gasification residue either in an atmospheric or a pressurised fluidised-bed. In this project, which is a part of European JOULE 2 EXTENSION research programme, the main research objectives are the behaviour of calcium and sulphur compounds in solids and the emissions of sulphur dioxide and nitrogen oxides (NO{sub x} and N{sub 2}O) in pressurised fluidised-bed combustion of gasification residues. (author)

  19. Modelling the bed characteristics in fluidised-beds for top-spray coating processes

    Institute of Scientific and Technical Information of China (English)

    Mike Vanderroost; Frederik Ronsse; Koen Dewettinck; Jan G.Pieters

    2012-01-01

    A particle sub-model describing the bed characteristics of a bubbling fluidised bed is presented.Atomisation air,applied at high pressures via a nozzle positioned above the bed for s pray formation,is incorporated in the model since its presence has a profound influence on the bed characteristics,though the spray itself is not yet considered.A particle sub-model is developed using well-known empirical relations for particle drag force,bubble growth and velocity and particle distribution above the fluidised-bed surface.Simple but effective assumptions and abstractions were made concerning bubble distribution,particle ejection at the bed surface and the behaviour of atomisation air flow upon impacting the surface of a bubbling fluidised bed.The model was shown to be capable of predicting the fluidised bed characteristics in terms of bed heights,voidage distributions and solids volume fractions with good accuracy in less than 5 min of calculation time on a regular desktop PC.It is therefore suitable for incorporation into general process control models aimed at dynamic control for process efficiency and product quality in top-spray fluidised bed coating processes.

  20. Passive acoustic monitoring of bed load discharge in a large gravel bed river

    Science.gov (United States)

    Geay, T.; Belleudy, P.; Gervaise, C.; Habersack, H.; Aigner, J.; Kreisler, A.; Seitz, H.; Laronne, J. B.

    2017-02-01

    Surrogate technologies to monitor bed load discharge have been developed to supplement and ultimately take over traditional direct methods. Our research deals with passive acoustic monitoring of bed load flux using a hydrophone continuously deployed near a river bed. This passive acoustic technology senses any acoustic waves propagated in the river environment and particularly the sound due to interparticle collisions emitted during bed load movement. A data set has been acquired in the large Alpine gravel-bedded Drau River. Analysis of the short-term frequency response of acoustic signals allows us to determine the origin of recorded noises and to consider their frequency variations. Results are compared with ancillary field data of water depth and bed load transport inferred from the signals of a geophone array. Hydrophone and geophone signals are well correlated. Thanks to the large network of deployed geophones, analysis of the spatial resolution of hydrophone measurements shows that the sensor is sensitive to bed load motion not only locally but over distances of 5-10 m (10-20% of river width). Our results are promising in terms of the potential use of hydrophones for monitoring bed load transport in large gravel bed rivers: acoustic signals represent a large river bed area, rather than being local; hydrophones can be installed in large floods; they can be deployed at a low cost and provide continuous monitoring at high temporal resolution.

  1. Paediatric burn unit in Portugal: Beds needed using a bed-day approach.

    Science.gov (United States)

    Santos, João V; Viana, João; Amarante, José; Freitas, Alberto

    2017-03-01

    Despite the high burden of children with burns, there is not a paediatric burn unit (PBU) in Portugal. We aimed to estimate the Portuguese health care providing needs on paediatric burns. We performed a nation-wide retrospective study, between 2009 and 2013, among less than 16 years-old inpatients with burns that met the transfer criteria to a burn unit in Portugal. A bed-day approach was used, targeting an occupancy rate of 70-75%, and possible locations were studied. The primary outcome was the number of beds needed, and secondary outcomes were the overload and revenue for each possible number of beds in a PBU. A total of 1155 children met the transfer criteria to a burn unit, representing a total of 17,371 bed-days. Occupancy rates of 11-bed, 12-bed, 13-bed and 14-bed PBU were, respectively, 79.7%, 75.3%, 71.0% and 66.8%. The 13-bed PBU scenario would represent an overload of 523 bed-days, revenue of more than 5 million Euros and a ratio of 1 PBU bed per 123,409 children. Using a groundbreaking approach, the optimal number of PBU beds needed in Portugal is 13. However, as half of the patients who met burn transfer criteria are not transferred, this bed number might be overestimated if this pattern maintains, despite the underestimation with our method approach. If a PBU is to be created the preferable location is Porto. Cost-effectiveness studies should be performed. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

  2. The paleomagnetism of the Salt Pseudomorph Beds of Middle Cambrian age from the Salt Range, West Pakistan

    NARCIS (Netherlands)

    Wensink, H.

    1972-01-01

    Oriented cores for a paleomagnetic investigation were collected from ten sites in the sedimentary redbeds of the Salt Pseudomorph Beds of Middle Cambrian age in the Salt Range near Khewra. All samples were subjected to progressive, thermal demagnetization procedures which revealed the characteristic

  3. The paleomagnetism of the salt pseudomorph beds of middle cambrian age from the salt range, West Pakistan

    NARCIS (Netherlands)

    Wensink, H.

    1972-01-01

    Oriented cores for a paleomagnetic investigation were collected from ten sites in the sedimentary redbeds of the Salt Pseudomorph Beds of Middle Cambrian age m the Salt Range near Khcwra. All samples were subjected to progressive, thermal demagnetization procedures which revealed the characteristic

  4. Riser simulation and radial porosity distribution characterization for gas-fluidized bed of cork particles

    Science.gov (United States)

    Wu, Guorong; Ouyang, Jie; Li, Qiang

    2014-08-01

    Numerical simulations are carried out for gas-solid fluidized bed of cork particles, using discrete element method. Results exhibit the existence of a so-called anti core-annular porosity profile with lower porosity in the core and higher porosity near the wall for non-slugging fluidization. The tendency to form this unfamiliar anti core-annular porosity profile is stronger when the solid flux is higher. There exist multiple inflection points in the simulated axial solid volume fraction profile for non-slugging fluidization. Results also show that the familiar core-annular porosity profile still appears for slugging fluidization. In addition, the classical choking phenomenon can be captured at the superficial gas velocity slightly lower than the correlated transport velocity.

  5. Recent numerical simulations and experiments on coolability of debris beds during severe accidents of light water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Starflinger, J., E-mail: joerg.starflinger@ike.uni-stuttgart.de; Buck, M.; Hartmann, A.; Kulenovic, R.; Leininger, S.; Rahman, S.; Rashid, M.

    2015-12-01

    Highlights: • Investigation on coolability of three-dimensional debris beds has been performed. • Computer code MEWA (Melt Water) is introduced and described briefly. • Validation experiments have been carried out in DEBRIS facility. • Comparison of MEWA simulations and DEBRIS experiments show good agreement. • Example simulation on reactor scale was performed to explain the analysis method. - Abstract: In the course of a severe accident in light water reactors with core degradation, so-called debris beds can be formed inside the reactor pressure vessel or in the reactor cavity. The strategy to analyse the coolability of such debris beds with both experiments and numerical simulations is discussed. The numerical simulations are carried out with MEWA (MElt WAter) code, being developed at the institute for the prediction of the thermal-hydraulic conditions inside a debris bed, including the prediction of dryout heat flux. The simulations show good agreement with experimental data of the DEBRIS experiments.

  6. Experimental analysis of the effect of vegetation on flow and bed shear stress distribution in high-curvature bends

    Science.gov (United States)

    Termini, Donatella

    2016-12-01

    The cross-sectional circulation, which develops in meandering bends, exerts an important role in velocity and the boundary shear stress redistributions. This paper considers the effect of vegetation on cross-sectional flow and bed shear distribution along a high-curvature bend. The analysis is conducted with the aid of data collected in a large-amplitude meandering flume during a reference experiment without vegetation and an experiment with vegetation on the bed. The results show that the presence of vegetation modifies the curvature-induced flow pattern and the directionality of turbulent structures. In fact, in the presence of vegetation, the turbulent structures tend to develop within and between the vegetated elements. The pattern of cross-sectional flow, modified by the presence of vegetation, affects the bed shear stress distribution along the bend so that the core of the highest value of the bed shear stress does not reach the outer bank.

  7. Comparison of predicted and measured fission product behavior in the Fort St. Vrain HTGR during the first three cycles of operation

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, D.L.; Jovanovic, V.; Burnette, R.D.

    1985-10-01

    Fission product release from the reactor core has been predicted by the reference design methods and compared with reactor surveillance measurements and with the results of postirradiation examination (PIE) of spent FSV fuel elements. Overall, the predictive methods have been shown to be conservative: the predicted fission gas release at the end of Cycle 3 is about five times higher than observed. The dominant source of fission gas release is as-manufactured, heavy-metal contamination; in-service failure of the coated fuel particles appears to be negligible which is consistent with the PIE of spent fuel elements removed during the first two refuelings. The predicted releases of fission metals are insignificant compared to the release and subsequent decay of their gaseous precursors which is consistent with plateout probe measurements.

  8. Effects of Spatial Variations in Packing Fraction on Reactor Physics Parameters in Pebble-Bed Reactors

    Energy Technology Data Exchange (ETDEWEB)

    William K. Terry; A. M. Ougouag; Farzad Rahnema; Michael Scott McKinley

    2003-04-01

    The well-known spatial variation of packing fraction near the outer boundary of a pebble-bed reactor core is cited. The ramifications of this variation are explored with the MCNP computer code. It is found that the variation has negligible effects on the global reactor physics parameters extracted from the MCNP calculations for use in analysis by diffusion-theory codes, but for local reaction rates the effects of the variation are naturally important. Included is some preliminary work in using first-order perturbation theory for estimating the effect of the spatial variation of packing fraction on the core eigenvalue and the fision density distribution.

  9. Experimental Study and Modelling of Char Combustion under Fluidized Bed Conditions

    Institute of Scientific and Technical Information of China (English)

    ZhangYongzhe; ManfredC.Wirsum; 等

    1998-01-01

    The combustion behavior of chars from two Chinese coals has been investigated in a laboratory scale bubbling fludized bed system in Siegen University,Germany,Experimental equipment and method are introduced.The shrinking-core model and the “shrinking-particl” model were employed to evaluate the kinetic parameters.The results indicated that the char conversion process of these two coals can be well described by the two models.

  10. Banded transformer cores

    Science.gov (United States)

    Mclyman, C. W. T. (Inventor)

    1974-01-01

    A banded transformer core formed by positioning a pair of mated, similar core halves on a supporting pedestal. The core halves are encircled with a strap, selectively applying tension whereby a compressive force is applied to the core edge for reducing the innate air gap. A dc magnetic field is employed in supporting the core halves during initial phases of the banding operation, while an ac magnetic field subsequently is employed for detecting dimension changes occurring in the air gaps as tension is applied to the strap.

  11. Stress Analysis of Coated Particle Fuel in the Deep-Burn Pebble Bed Reactor Design

    Energy Technology Data Exchange (ETDEWEB)

    B. Boer; A. M. Ougouag

    2010-05-01

    High fuel temperatures and resulting fuel particle coating stresses can be expected in a Pu and minor actinide fueled Pebble Bed Modular Reactor (400 MWth) design as compared to the ’standard’ UO2 fueled core. The high discharge burnup aimed for in this Deep-Burn design results in increased power and temperature peaking in the pebble bed near the inner and outer reflector. Furthermore, the pebble power in a multi-pass in-core pebble recycling scheme is relatively high for pebbles that make their first core pass. This might result in an increase of the mechanical failure of the coatings, which serve as the containment of radioactive fission products in the PBMR design. To investigate the integrity of the particle fuel coatings as a function of the irradiation time (i.e. burnup), core position and during a Loss Of Forced Cooling (LOFC) incident the PArticle STress Analysis code (PASTA) has been coupled to the PEBBED code for neutronics, thermal-hydraulics and depletion analysis of the core. Two deep burn fuel types (Pu with or without initial MA fuel content) have been investigated with the new code system for normal and transient conditions including the effect of the statistical variation of thickness of the coating layers.

  12. Review of the Technical Status on the Debris Bed Cooling Model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eui Kwang; Cho, Chung Ho; Lee, Yong Bum

    2007-09-15

    Preliminary safety analyses of the KALIMER-600 design have shown that the design has inherent safety characteristics and is capable of accommodating double-fault initiators such as ATWS events without coolant boiling or fuel melting. However, for the future design of sodium cooled fast reactor, the evaluation of the safety performance and the determination of containment requirements may be worth due consideration of triple-fault accident sequences of extremely low probability of occurrence that leads to core melting. For any postulated accident sequence which leads to core melting, in-vessel retention of the core debris will be required as a design requirement for the future design of sodium cooled fast reactor. Also, proof of the capacity of the debris bed cooling is an essential condition to solve the problem of in-vessel retention of the core debris. In this study, review of the technical status on the debris bed cooling model was carried out for in-vessel retention of the core debris0.

  13. Numerical Model for the Analysis of Coolability of a Particulate Debris Bed with Single Phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Cho, C. H.; Jeong, H. Y.; Chang, W. P.; Kwon, Y. M.; Lee, Y. B

    2008-01-15

    Preliminary safety analyses of the KALIMER-600 design have shown that the design has inherent safety characteristics and is capable of accommodating double-fault initiators such as ATWS events without coolant boiling or fuel melting. However, for the future design of sodium cooled fast reactor, the evaluation of the safety performance and the determination of containment requirements may be worth due consideration of triple-fault accident sequences of extremely low probability of occurrence that leads to core melting. For any postulated accident sequence which leads to core melting, in-vessel retention of the core debris will be required as a design requirement for the future design of sodium cooled fast reactor. Also, proof of the capacity of the debris bed cooling is an essential condition to solve the problem of in-vessel retention of the core debris. Accordingly, Numerical model development for the Analysis of coolability of a particulate debris bed with single phase flow was carried out for in-vessel retention of the core debris.

  14. Revaluation of a Coolability of a Packed Debris Bed with a Single Phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chungho; Suk, S. D.; Jeong, H. Y.; Kwon, Y. M.; Lee, Y. B

    2008-09-15

    Preliminary safety analyses of the KALIMER-600 design have shown that the design has inherent safety characteristics and is capable of accommodating double-fault initiators such as ATWS events without coolant boiling or fuel melting. However, for the future design of sodium cooled fast reactor, the evaluation of the safety performance and the determination of containment requirements may be worth due consideration of triple-fault accident sequences of extremely low probability of occurrence that leads to core melting. For any postulated accident sequence which leads to core melting, in-vessel retention of the core debris will be required as a design requirement for the future design of sodium cooled fast reactor. Also, proof of the capacity of the debris bed cooling is an essential condition to solve the problem of in-vessel retention of the core debris. Accordingly, evaluation of coolability of a packed debris bed with single phase flow was carried out for proof of the in-vessel retention of the core debris.

  15. Bed Bug Infestations and Control Practices in China: Implications for Fighting the Global Bed Bug Resurgence

    Directory of Open Access Journals (Sweden)

    Changlu Wang

    2011-04-01

    Full Text Available The bed bug resurgence in North America, Europe, and Australia has elicited interest in investigating the causes of the widespread and increasing infestations and in developing more effective control strategies. In order to extend global perspectives on bed bug management, we reviewed bed bug literature in China by searching five Chinese language electronic databases. We also conducted telephone interviews of 68 pest control firms in two cities during March 2011. In addition, we conducted telephone interviews to 68 pest control companies within two cities in March 2011. Two species of bed bugs (Cimex lectularius L. and Cimex hemipterus (F. are known to occur in China. These were common urban pests before the early1980s. Nationwide “Four-Pest Elimination” campaigns (bed bugs being one of the targeted pests were implemented in China from 1960 to the early 1980s. These campaigns succeeded in the elimination of bed bug infestations in most communities. Commonly used bed bug control methods included applications of hot water, sealing of bed bug harborages, physical removal, and applications of residual insecticides (mainly organophosphate sprays or dusts. Although international and domestic travel has increased rapidly in China over the past decade (2000–2010, there have only been sporadic new infestations reported in recent years. During 1999–2009, all documented bed bug infestations were found in group living facilities (military dormitories, worker dormitories, and prisons, hotels, or trains. One city (Shenzhen city near Hong Kong experienced significantly higher number of bed bug infestations. This city is characterized by a high concentration of migratory factory workers. Current bed bug control practices include educating residents, washing, reducing clutter, putting items under the hot sun in summer, and applying insecticides (pyrethroids or organophosphates. There have not been any studies or reports on bed bug insecticide

  16. Ultra high temperature particle bed reactor design

    Science.gov (United States)

    Lazareth, Otto; Ludewig, Hans; Perkins, K.; Powell, J.

    1990-01-01

    A direct nuclear propulsion engine which could be used for a mission to Mars is designed. The main features of this reactor design are high values for I(sub sp) and very efficient cooling. This particle bed reactor consists of 37 cylindrical fuel elements embedded in a cylinder of beryllium which acts as a moderator and reflector. The fuel consists of a packed bed of spherical fissionable fuel particles. Gaseous H2 passes over the fuel bed, removes the heat, and is exhausted out of the rocket. The design was found to be neutronically critical and to have tolerable heating rates. Therefore, this particle bed reactor design is suitable as a propulsion unit for this mission.

  17. Is bed rest following embryo transfer necessary?

    Science.gov (United States)

    Sharif, K; Afnan, M; Lashen, H; Elgendy, M; Morgan, C; Sinclair, L

    1998-03-01

    To evaluate the effect of no bed rest following ET on the results of an IVF program. Historical cohort-control study. A University-based assisted conception unit. One thousand and nineteen (1019) IVF cycles were performed at our unit from June 1994 to August 1996. The historical control consisted of all the 19,697 IVF cycles reported in the United Kingdom national database from April 1994 to March 1995. No bed rest following ET in our patients. Pregnancy rate (PR) and clinical PR per cycles started and per ET procedure. The clinical PR per ET was significantly higher in our patients than in the national data (30% versus 22.9%), as was the clinical PR per cycle (23.5% versus 18.6%). The implantation rate in our patients was 17.2%. The favorable PR in our patients despite no bed rest following ET suggests the bed rest is not necessary.

  18. D7 debris-bed experiment. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, G W; Ottinger, C A; Lipinski, R J

    1983-08-01

    The D7 experiment investigated heat removal from a shallow, stratified bed of UO/sub 2/ particulate in sodium. The particle diameters ranged from 0.1 to 1.0 mm, with the largest particles at the bottom. The bed thickness was 74 mm and the average porosity was 41%. The incipient dryout power varied from 0.43 W/g to 0.25 W/g as the sodium subcooling (saturation temperature minus overlying pool temperature) was reduced from 390/sup 0/C to 170/sup 0/C. These powers were only slighlty above the incipient boiling powers. Such low dryout powers are believed due to the interaction of capillary force with bed stratification. With a subccoling of 130/sup 0/C several sudden decreases in the saturation temperature occurred. These are believed due to channel formation, which causes a reduction in the capillary pressure in the bed.

  19. Modular Electric Propulsion Test Bed Aircraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An all electric aircraft test bed is proposed to provide a dedicated development environment for the rigorous study and advancement of electrically powered aircraft....

  20. Protecting Your Home from Bed Bugs

    Science.gov (United States)

    ... bed bugs easier to see. Be sure to purchase a high quality encasement that will resist tearing ... Contact Us Hotlines FOIA Requests Frequent Questions Follow. Facebook Twitter YouTube Flickr Instagram Last updated on December ...

  1. IceBridge BedMachine Greenland

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains bed topography beneath the Greenland Ice Sheet based on mass conservation derived from airborne radar tracks and satellite radar. The data...

  2. Bed Bug Clearinghouse Publications in Other Languages

    Science.gov (United States)

    This information is intended to help states, communities, and consumers prevent and control bed bug infestations. These outreach materials are available in Spanish, Chinese, and French; and include action plans based on an IPM approach.

  3. Adult Bed-Wetting: A Concern?

    Science.gov (United States)

    ... D. Bed-wetting that starts in adulthood (secondary enuresis) is uncommon and requires medical evaluation. Causes of ... Erik P. Castle, M.D. References Adult nocturnal enuresis. National Association for Continence. http://www.nafc.org/ ...

  4. Bed Bugs are Public Health Pests

    Science.gov (United States)

    EPA and the Centers for Disease Control and Prevention (CDC) issued a joint statement on the public health impacts of bed bugs, which are blood-sucking ectoparasites (external parasites). EPA also has a pesticide registration notice on this topic.

  5. Do-it-yourself Bed Bug Control

    Science.gov (United States)

    Controlling bed bugs is complex. Using an integrated pest management (IPM) approach incorporates both non-chemical and pesticide methods. Success depends on the extent of the infestation, clutter on site, and resident participation.

  6. Modular Electric Propulsion Test Bed Aircraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A hybrid electric aircraft simulation system and test bed is proposed to provide a dedicated development environment for the rigorous study and advancement of hybrid...

  7. PRESSURE FLUCTUATIONS IN GAS-SOLIDS FLUIDIZED BEDS

    Institute of Scientific and Technical Information of China (English)

    Hsiaotao Bi; Aihua Chen

    2003-01-01

    Pressure fluctuation data measured in a series of fluidized beds with diameters of 0.05, 0.1, 0.29, 0.60 and 1.56 m showed that the maximum amplitude or standard deviation increased with increasing the superficial gas velocity and static bed height for relatively shallow beds and became insensitive to the increase in static bed height in relatively deep beds. The amplitude appeared to be less dependent on the measurement location in the dense bed. Predictions based on bubble passage, bubble eruption at the upper bed surface and bed oscillation all failed to explain all observed trends and underestimated the amplitude of pressure fluctuations, suggesting that the global pressure fluctuations in gas-solids bubbling fluidized beds are the superposition of local pressure variations, bed oscillations and pressure waves generated from the bubble formation in the distributor region, bubble coalescence during their rise and bubble eruption at the upper bed surface.

  8. The influence of fibrous bed bulk density on the bed properties

    Directory of Open Access Journals (Sweden)

    Šećerov-Sokolović Radmila M.

    2003-01-01

    Full Text Available The mean properties of seven different fibrous materials and the properties of their different bed bulk densities were investigated. The morphology of the surface, size and geometry were measured by optical microscopy. The bed porosity was measured by the weighing method. The experimental bed permeability, in a high range of bulk density, was calculated from the values of the sanitary water pressure drop at a constant temperature of 15°C, since the data followed Darcy's law. The Reynolds number for a fibrous bed was calculated using a relation from the literature. The Reynolds number was less than 1 for all ranges of fluid velocity. Three empirical relations for fibrous bed permeability were used and compared with the experimental data. It was determined that the empirical data depended on the fiber diameter and fraction of solid in the bed. The relative error linearly increased with increasing fiber diameter.

  9. The effect of vibration on bed voidage behaviors in fluidized beds with large particles

    Energy Technology Data Exchange (ETDEWEB)

    Jin, H.; Zhang, J.; Zhang, B.

    2007-07-01

    The effects of vibration parameters, operating conditions and material properties on bed voidage were investigated using an optical fiber probe approach in a vibrating fluidized bed with a diameter of 148 mm. Variables studied included frequency (0-282 s{sup -1}), amplitude (0 mm-1 mm), bed height (0.1 m-0.4 m) as well as four kinds of particles (belonging to Geldart's B and D groups). The axial and radial voidage distribution with vibration is compared with that without vibration, which shows vibration can aid in the fluidization behaviors of particles. For a larger vibration amplitude, the vibration seriously affects bed voidage. The vibration energy can damp out for particle layers with increasing the bed height. According to analysis of experimental data, an empirical correlation for predicting bed voidage, giving good agreement with the experimental data and a deviation within {+-}15%, was proposed. 20 refs., 8 figs., 2 tabs.

  10. Bed dynamics of gas-solid fluidized bed with rod promoter

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The dynamic characteristics of a gas-solid fluidized bed with different rod promoters have been investigated in terms of bed expansion and fluctuation, minimum fluidization velocity and distributor-to-bed pressure drop ratio at minimum fluidization velocity. Experimentation based on statistical design has been carried out and model equations using factorial design of experiments have been developed for the above mentioned quantities for a promoted gas-solid fluidized bed. The model equations have been tested with additional experimental data. The system variables include four types of rod promoters of varying blockage volume, bed particles of four sizes and four initial static bed heights. A comparison between the predicted values of the output variables using the proposed model equation with their corresponding experimental ones shows fairly good agreement.

  11. The effect of vibration on bed voidage behaviors in fluidized beds with large particles

    Directory of Open Access Journals (Sweden)

    H. Jin

    2007-09-01

    Full Text Available The effects of vibration parameters, operating conditions and material properties on bed voidage were investigated using an optical fiber probe approach in a vibrating fluidized bed with a diameter of 148 mm. Variables studied included frequency (0-282 s-1, amplitude (0 mm-1 mm, bed height (0.1 m-0.4 m as well as four kinds of particles (belonging to Geldart's B and D groups. The axial and radial voidage distribution with vibration is compared with that without vibration, which shows vibration can aid in the fluidization behaviors of particles. For a larger vibration amplitude, the vibration seriously affects bed voidage. The vibration energy can damp out for particle layers with increasing the bed height. According to analysis of experimental data, an empirical correlation for predicting bed voidage, giving good agreement with the experimental data and a deviation within ±15%, was proposed.

  12. Fission-product releases from a PHWR terminal debris bed

    Energy Technology Data Exchange (ETDEWEB)

    Brown, M.J.; Bailey, D.G., E-mail: morgan.brown@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2016-06-15

    During an unmitigated severe accident in a pressurized heavy water reactor (PHWR) with horizontal fuel channels, the core may disassemble and relocate to the bottom of the calandria vessel. The resulting heterogeneous in-vessel terminal debris bed (TDB) would likely be quenched by any remaining moderator, and some of the decay heat would be conducted through the calandria vessel shell to the surrounding reactor vault or shield tank water. As the moderator boiled off, the solid debris bed would transform into a more homogeneous molten corium pool located between top and bottom crusts. Until recently, the severe accident code MAAP-CANDU assumed that unreleased volatile and semi-volatile fission products remained in the TDB until after calandria vessel failure, due to low diffusivity through the top crust and the lack of gases or steam to flush released fission products from the debris. However, national and international experimental results indicate this assumption is unlikely; instead, high- and medium-volatility fission products would be released from a molten debris pool, and their volatility and transport should be taken into account in TDB modelling. The resulting change in the distribution of fission products within the reactor and containment, and the associated decay heat, can have significant effects upon the progression of the accident and fission-product releases to the environment. This article describes a postulated PHWR severe accident progression to generate a TDB and the effects of fission-product releases from the terminal debris, using the simple release model in the MAAP-CANDU severe accident code. It also provides insights from various experimental programs related to fission-product releases from core debris, and their applicability to the MAAP-CANDU TDB model. (author)

  13. Pressure fluctuations in gas fluidized beds

    OpenAIRE

    Leckner Bo.; Palchonok Genadij I.; Johnsson Filip

    2002-01-01

    The pressure fluctuations in a fluidized bed are a result of the actions of the bubbles. However, the bubbles may be influenced by the air supply system and by the pressure drop of the air distributor. These interactions are treated for low as well as for high velocity beds by means of a simple model of the principal frequency of the pressure fluctuations. The model includes the interaction with the air supply system and describes qualitatively two important bubbling regimes: the single bubbl...

  14. BNNT Growth in a Fluidized Bed Reactor

    Science.gov (United States)

    2016-06-24

    fluidized bed and plasma assisted nanotube synthesis for the growth of boron nitride nanotubes (BNNT). Within this context, we established new...bed and plasma assisted nanotube synthesis for the growth of boron nitride nanotubes (BNNT). Within this context, we established new laboratories to...the path of using plasma assistance to growth BNNT in a manner similar to that of researchers at the Canadian Research Council. With our combined

  15. Experimental investigation of the pebble bed structure by using gamma ray tomography

    Science.gov (United States)

    Ahmed, Fadha Shakir

    Pebble Bed Reactors offer a future for new nuclear energy plants. They are small, inherently safe, and can be competitive with fossil fuels. The fuel forms a randomly stacked pebble with non-uniform fuel densities. The thermal-mechanical behavior of pebble bed reactor core is depends strongly on the spatial variation of packing fraction in the bed and in particular on the number of contacts between pebbles, and between the pebbles and the blanket walls. To investigate these effects, experimental data to characterize bed structure are needed along with other numerical simulation and computational tools for validation. In this study, a powerful technique of high-energy gamma-ray computed tomography (CT scanner system) is employed for the first time for the quantification of the structure of pebble bed in term of the cross-sectional time-averaged void and distributions, it radial profiles and the statistical analysis. The alternative minimization (AM) iteration algorithm is used for image reconstruction. The spatial resolution of the CT scan is about 2 mm with 100 x 100 pixel used to reconstruct the cross-sectional image. Results of tomography with this advanced technique on three different pebble sizes at different axial levels are presented. The bed consisted of a glass spheres (Marbles) with a diameter d1= 1.27 cm, d2= 2.54 cm and d3= 5 cm in a Plexiglas cylinder with diameter D = 30.48 cm (D/d1 = 24, D/d2 = 12 and D/d3 = 6), and had an average void fraction epsilon1= 0.389, epsilon2 = 0.40 and epsilon 3 =0.43, respectively. The radial void fraction profile showed large oscillations with the bigger pebble diameters and the void fraction is higher on the wall with a minimum void fraction of 0.33 at 0.68 pebble diameter away from the wall. It was found that the void distribution in random packed bed depends strongly on the pebble diameter with respect to the bed diameter (D/d p) and the packing mode. The oscillation is quiet large with the smaller aspect ratio (D

  16. Water produced with coal-bed methane

    Science.gov (United States)

    ,

    2000-01-01

    Natural gas produced from coal beds (coal-bed methane, CBM) accounts for about 7.5 percent of the total natural gas production in the United States. Along with this gas, water is also brought to the surface. The amount of water produced from most CBM wells is relatively high compared to conventional natural gas wells because coal beds contain many fractures and pores that can contain and transmit large volumes of water. In some areas, coal beds may function as regional or local aquifers and important sources for ground water. The water in coal beds contributes to pressure in the reservoir that keeps methane gas adsorbed to the surface of the coal. This water must be removed by pumping in order to lower the pressure in the reservoir and stimulate desorption of methane from the coal (fi g. 1). Over time, volumes of pumped water typically decrease and the production of gas increases as coal beds near the well bore are dewatered.

  17. Calculating the need for intensive care beds.

    Science.gov (United States)

    Pearson, Gale A; Reynolds, Fiona; Stickley, John

    2012-11-01

    Prompted by high refused admission rates, we sought to model demand for our 20 bed paediatric intensive care unit. We analysed activity (admissions) and demand (admissions plus refused admissions). The recommended method for calculating the required number of intensive care beds assumes a Poisson distribution based upon the size of the local catchment population, the incidence of intensive care admission and the average length of stay. We compared it to the Monte Carlo method which would also include supra-regional referrals not otherwise accounted for but which, due to their complexity, tend to have a longer stay than average. For the new method we assigned data from randomly selected emergency admissions to the refused admissions. We then compared occupancy scenarios obtained by random sampling from the data with replacement. There was an increase in demand for intensive care over time. Therefore, in order to provide an up-to-date model, we restricted the final analysis to data from the two most recent years (2327 admissions and 324 refused admissions). The conventional method suggested 27 beds covers 95% of the year. The Monte Carlo method showed 95% compliance with 34 beds, with seasonal variation quantified as 30 beds needed in the summer and 38 in the winter. Both approaches suggest that the high refused admission rate is due to insufficient capacity. The Monte Carlo analysis is based upon the total workload (including supra-regional referrals) and predicts a greater bed requirement than the current recommended approach.

  18. WTP Pretreatment Facility Potential Design Deficiencies--Sliding Bed and Sliding Bed Erosion Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, E. K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-05-06

    This assessment is based on readily available literature and discusses both Newtonian and non-Newtonian slurries with respect to sliding beds and erosion due to sliding beds. This report does not quantify the size of the sliding beds or erosion rates due to sliding beds, but only assesses if they could be present. This assessment addresses process pipelines in the Pretreatment (PT) facility and the high level waste (HLW) transfer lines leaving the PT facility to the HLW vitrification facility concentrate receipt vessel.

  19. CFD-DEM study of effect of bed thickness for bubbling fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Tingwen, Li; Gopalakrishnan, Pradeep; Garg, Rahul; Shahnam, Mehrdad

    2011-10-01

    The effect of bed thickness in rectangular fluidized beds is investigated through the CFD–DEM simulations of small-scale systems. Numerical results are compared for bubbling fluidized beds of various bed thicknesses with respect to particle packing, bed expansion, bubble behavior, solids velocities, and particle kinetic energy. Good two-dimensional (2D) flow behavior is observed in the bed having a thickness of up to 20 particle diameters. However, a strong three-dimensional (3D) flow behavior is observed in beds with a thickness of 40 particle diameters, indicating the transition from 2D flow to 3D flow within the range of 20–40 particle diameters. Comparison of velocity profiles near the walls and at the center of the bed shows significant impact of the front and back walls on the flow hydrodynamics of pseudo-2D fluidized beds. Hence, for quantitative comparison with experiments in pseudo-2D columns, the effect of walls has to be accounted for in numerical simulations.

  20. Multiscale statistical characterization of migrating bed forms in gravel and sand bed rivers

    Science.gov (United States)

    Singh, Arvind; Lanzoni, Stefano; Wilcock, Peter R.; Foufoula-Georgiou, Efi

    2011-12-01

    Migrating bed forms strongly influence hydraulics, transport, and habitat in river environments. Their dynamics are exceedingly complex, making it difficult to predict their geometry and their interaction with sediment transport. Acoustic instrumentation now permits high-resolution observations of bed elevation as well as flow velocity. We present a space-time characterization of bed elevation series in laboratory experiments of sand and gravel transport in a large 84 m long, 2.75 m wide flume. We use a simple filtering and thresholding methodology to estimate bed form heights and report that the shape of their probability density function (pdf) remains invariant to discharge for both gravel and sand and has a positive tail slightly thicker than Gaussian. Using a wavelet decomposition, we quantify the presence of a rich multiscale statistical structure and estimate the scale-dependent celerity of migrating bed forms, showing the faster movement of smaller bed forms relative to the larger ones. The nonlinear dynamics of gravel and sand bed forms is also examined, and the predictability time, i.e., the interval over which one can typically forecast the system, is estimated. Our results demonstrate that flow rate as well as bed sediment composition exert a significant influence on the multiscale dynamics and degree of nonlinearity and complexity of bed form evolution.

  1. 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.

  2. CFD-DEM study of effect of bed thickness for bubbling fluidized beds

    Institute of Scientific and Technical Information of China (English)

    Tingwen Li; Pradeep Gopalakrishnana; Rahul Garg; Mehrdad Shahnam

    2012-01-01

    The effect of bed thickness in rectangular fluidized beds is investigated through the CFD-DEM simulations of small-scale systems.Numerical results are compared for bubbling fluidized beds of various bed thicknesses with respect to particle packing,bed expansion,bubble behavior,solids velocities,and particle kinetic energy.Good two-dimensional (2D) flow behavior is observed in the bed having a thickness of up to 20 particle diameters.However,a strong three-dimensional (3D) flow behavior is observed in beds with a thickness of 40 particle diameters,indicating the transition from 2D flow to 3D flow within the range of 20-40 particle diameters.Comparison of velocity profiles near the walls and at the center of the bed shows significant impact of the front and back walls on the flow hydrodynamics of pseudo-2D fluidized beds.Hence,for quantitative comparison with experiments in pseudo-2D columns,the effect of wails has to be accounted for in numerical simulations.

  3. Effects of bed height on the biomechanics of hospital bed entry and egress.

    Science.gov (United States)

    Merryweather, Andrew S; Morse, Janice M; Doig, Alexa K; Godfrey, Nathan W; Gervais, Pierre; Bloswick, Donald S

    2015-01-01

    Although a significant proportion of patient falls in hospitals occur in the vicinity of the hospital bed, little is known about the contribution of bed height to fall risk. To compare lower extremity joint torques and angles during hospital bed entry and egress at two bed heights. Twelve adults (age > 55) were purposively selected and had variety of strength and mobility limitations. Biomechanical data for this pilot study were collected with three digital video cameras and processed to obtain estimates for joint torques and included angles. At the low bed height, hip torque for bed entry was significantly higher, and hip, knee, and ankle flexion angles were significantly smaller. The absence of significant differences in knee and ankle torques were the result of a compensation strategy that shifts the center of mass forward by flexing the torso during low bed ingress. Torque data from the egress motion were similar, however 50% of participants were unable to rise from the low bed without assistance. Healthcare providers should be aware that low bed heights pose safety risks to the population for which they were designed-elderly persons at high risk for falling.

  4. Preliminary assessment of existing experimental data for validation ofreactor physics codes and data for NGNP design and analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Terry, W. K.; Jewell, J. K.; Briggs, J. B.; Taiwo, T. A.; Park, W.S.; Khalil, H. S.

    2005-10-25

    The Next Generation Nuclear Plant (NGNP), a demonstration reactor and hydrogen production facility proposed for construction at the INEEL, is expected to be a high-temperature gas-cooled reactor (HTGR). Computer codes used in design and safety analysis for the NGNP must be benchmarked against experimental data. The INEEL and ANL have examined information about several past and present experimental and prototypical facilities based on HTGR concepts to assess the potential of these facilities for use in this benchmarking effort. Both reactors and critical facilities applicable to pebble-bed and prismatic block-type cores have been considered. Four facilities--HTR-PROTEUS, HTR-10, ASTRA, and AVR--appear to have the greatest potential for use in benchmarking codes for pebble-bed reactors. Similarly, for the prismatic block-type reactor design, two experiments have been ranked as having the highest priority--HTTR and VHTRC.

  5. Experimental investigations on the coolability of prototypical particle beds with respect to reactor safety; Experimentelle Untersuchungen der Kuehlbarkeit prototypischer Schuettungskonfigurationen unter dem Aspekt der Reaktorsicherheit

    Energy Technology Data Exchange (ETDEWEB)

    Leininger, Simon

    2017-02-22

    In case of a severe accident in a light water reactor, continuous unavailability of cooling water to the reactor core may result in overheating of the fuel elements and finally the loss of core integrity. Under such conditions, a structure of heat-releasing particles of different size and shape may be formed by fragmentation of molten core material in several stages of the accident. The long-term coolability of such beds is of prime im-portance to avoid any damage to the reactor pressure vessel or even a release of fission products to the environment. In the frame of this work, specific experiments were con-ducted under prototypical conditions employing the existing DEBRIS test facility in order to gain further knowledge about the thermohydraulic behavior of such beds. In steady state boiling experiments, the pressure gradients in particle beds were meas-ured both for one- and multi-dimensional cooling water flow conditions and compared with one another in order to assess the flow behavior inside the bed. For these different flow conditions as well as for stratified bed configurations, the maximum removable heat flux densities were determined in the dryout experiments. E. g., it was found that an axial stratification of the permeability can significantly reduce the bed's coolability. For the first time, the quenching behavior of dry, superheated beds was investigated at elevated system pressure up to 0.5 MPa. In these experiments, the effect of system pressure on the coolability was quantified by means of the quenching time (time period to cool down the bed to saturation temperature). The investigated particle beds mainly consisted of non-spherical particles with well-defined geometry (cylinders and screws). It was shown that the effect of the particles geometry on the flow in a particle bed can be best estimated by using an equivalent particle diameter calculated for monodisperse particle beds from the product of the Sauter diameter and a shape factor and for

  6. 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

  7. Carbon dioxide fumigation for controlling bed bugs.

    Science.gov (United States)

    Wang, Changlu; Lü, Lihua; Xu, Ming

    2012-09-01

    We investigated the potential of carbon dioxide (CO2) fumigation as a method for controlling bed bugs, Cimex lectularius L. The effect of bed bug developmental stage, temperature, and CO2 concentration on the minimum time to kill 100% of bed bugs was determined. The minimum CO2 concentration lethal to all bed bug stages was approximately 30% with 24 h exposure time at 25 degrees C. The minimum fumigation time required to kill 100% of eggs using 100% CO2 at 20, 25, and 30 degrees C were 3, 7, and 8 h, respectively; the minimum fumigation time to kill 100% of adult males/nymphs were 8, 13, and 14 h, respectively. The minimum time to kill 100% of adult males/nymphs using 50 and 70% CO2 at 25 degrees C were 18 and 16 h, respectively. We found that eggs were not completely killed after 24 h fumigation when the CO2 concentration was lower than 80%. Thus, bed bug eggs were more susceptible to 100% CO2 fumigation than nymphs and adult males but more tolerant than nymphs and adult males with lower CO2 concentration (50-80%). There were no significant differences among nymphs, adult males, and adult females in their susceptibility to 100% CO2 fumigation. A 24 h fumigation in sealed 158 liter (42 gallon) heavy duty garbage bags filled 90% full with fabric materials and/or boxes and 1,350 g dry ice per bag was sufficient to kill all stages of bed bugs hidden in the materials at room temperature (23-24 degrees C). Sealed heavy duty garbage bags maintained > or = 94% CO2 for at least 24 h. Custom-made double zipper plastic bags (122 x 183 cm) were also used to evaluate the effectiveness of CO2 fumigation for controlling bed bugs. Each bag was filled with fabric and boxes to 50-90% full. Bed bugs were hidden in various locations of each bag. CO2 was introduced into the bags through a CO2 cylinder. CO2 fumigation lasting 24-48 h was sufficient to kill all stages of bed bugs at room temperature, depending on the quantity of materials placed in each bag and whether CO2 was

  8. 21 CFR 880.5120 - Manual adjustable hospital bed.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Manual adjustable hospital bed. 880.5120 Section... Therapeutic Devices § 880.5120 Manual adjustable hospital bed. (a) Identification. A manual adjustable hospital bed is a device intended for medical purposes that consists of a bed with a manual...

  9. 21 CFR 892.1350 - Nuclear scanning bed.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear scanning bed. 892.1350 Section 892.1350...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1350 Nuclear scanning bed. (a) Identification. A nuclear scanning bed is an adjustable bed intended to support a patient during a nuclear...

  10. Effectiveness of bed bug monitors for detecting and trapping bed bugs in apartments.

    Science.gov (United States)

    Wang, Changlu; Tsai, Wan-Tien; Cooper, Richard; White, Jeffrey

    2011-02-01

    Bed bugs, Cimex lectularius L., are now considered a serious urban pest in the United States. Because they are small and difficult to find, there has been strong interest in developing and using monitoring tools to detect bed bugs and evaluate the results of bed bug control efforts. Several bed bug monitoring devices were developed recently, but their effectiveness is unknown. We comparatively evaluated three active monitors that contain attractants: CDC3000, NightWatch, and a home-made dry ice trap. The Climbup Insect Interceptor, a passive monitor (without attractants), was used for estimating the bed bug numbers before and after placing active monitors. The results of the Interceptors also were compared with the results of the active monitors. In occupied apartments, the relative effectiveness of the active monitors was: dry ice trap > CDC3000 > NightWatch. In lightly infested apartments, the Interceptor (operated for 7 d) trapped similar number of bed bugs as the dry ice trap (operated for 1 d) and trapped more bed bugs than CDC3000 and NightWatch (operated for 1 d). The Interceptor was also more effective than visual inspections in detecting the presence of small numbers of bed bugs. CDC3000 and the dry ice trap operated for 1 d were equally as effective as the visual inspections for detecting very low level of infestations, whereas 1-d deployment of NightWatch detected significantly lower number of infestations compared with visual inspections. NightWatch was designed to be able to operate for several consecutive nights. When operated for four nights, NightWatch trapped similar number of bed bugs as the Interceptors operated for 10 d after deployment of NightWatch. We conclude these monitors are effective tools in detecting early bed bug infestations and evaluating the results of bed bug control programs.

  11. [Comparison of PAHs distribution in stabilized sludge by sludge drying bed and reed bed].

    Science.gov (United States)

    Cui, Yu-Bo; Sun, Hong-Jie; Ran, Chun-Qiu; Li, Jin-Feng; Xie, Yao

    2013-03-01

    The difference in the removal efficiencies of polycyclic aromatic hydrocarbons (PAHs) in planted and unplanted sludge drying bed was investigated. Pilot-scale sludge drying bed and reed bed had the same size of 3.0 m x 1.0 m x 1.3 m (L x W x H), and the bed height consisted of a 65 cm media layer and a 65 cm super height. Both beds had a ventilation pipe which was mounted on the drainage pipes. The experiment lasted for three years, and the first two years was the sludge loading period, and the third year was the natural stabilization period. In the first two years, a total thickness of 8.4 m of sludge was loaded and the average sludge loading rate was 41.3 kg x (m2 x a)(-1). After the three-year stabilization, the contents of the sixteen PAHs decreased with time in both the sludge drying bed and the reed bed. The total PAHs contents in the surface, middle and bottom sludge layers in the sludge drying bed were 4.161, 3.543 and 3.118 mg x kg(-1) (DW), corresponding to 26.91%, 37.77% and 45.23% of removal; and the values in the reed bed were 2.722, 1.648 and 1.218 mg x kg(-1) (DW), corresponding to 52.18%, 71.05% and 78.60% of removal. The average PAHs removal in the reed bed was 29.86% higher than that in the sludge drying bed. In the stabilized sludge, the removal of low-molecular-weight PAHs predominated. The results suggested that reed played a positive role in the removal of PAHs.

  12. The core paradox.

    Science.gov (United States)

    Kennedy, G. C.; Higgins, G. H.

    1973-01-01

    Rebuttal of suggestions from various critics attempting to provide an escape from the seeming paradox originated by Higgins and Kennedy's (1971) proposed possibility that the liquid in the outer core was thermally stably stratified and that this stratification might prove a powerful inhibitor to circulation of the outer core fluid of the kind postulated for the generation of the earth's magnetic field. These suggestions are examined and shown to provide no reasonable escape from the core paradox.

  13. K-core inflation

    OpenAIRE

    Alexander L. Wolman

    2011-01-01

    K-core inflation is a new class of underlying inflation measures. The two most popular measures of underlying inflation are core inflation and trimmed mean inflation. The former removes fixed categories of goods and services (food and energy) from the inflation calculation, and the latter removes fixed percentiles of the weighted distribution of price changes. In contrast, k-core inflation specifies a size of relative price change to be removed from the inflation calculation. Thus, the catego...

  14. Sediment Core Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides instrumentation and expertise for physical and geoacoustic characterization of marine sediments. DESCRIPTION: The multisensor core logger measures...

  15. Sediment Core Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides instrumentation and expertise for physical and geoacoustic characterization of marine sediments.DESCRIPTION: The multisensor core logger measures...

  16. Preliminary Assessment of a Debris Bed Cooling Performance for Demonstration Sodium-cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chung Ho; Park, Chang Gyu; Song, Hoon; Kim, Young Gyun; Jeong, Hae Yong; Chang, Jin Wook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    In the case of the sodium-cooled fast reactor such as KALIMER-600, Hypothetical Core Disruptive Accident (HCDA) attributed from mass nuclear fuel melting is unlikely to occur due to defense in depth concepts to meet requirements of redundancy and diversity. Multiple faults such as loss of flow, loss of heat sink, or transient overpower without scram are to lead rising the power level until cladding failure as reactivity increasing. The fact that metallic fuel melts at a lower temperature than the cladding allows significant in-pin- fuel motion to occur prior to cladding failure. Also, the combination of Doppler and axial expansion feedback and negative feedback associated with the in-pin fuel relocation prevents the reactivity from reaching prompt critical. Finally, the resulting reactivity and power reductions help prevent fuel temperatures from rising more than the fuel melting temperature. It is more difficult to occur HCDA in a metallic fueled core because reactor power and heat removal capability is maintained in balance by inherent safety characteristics However, for the future design of sodium-cooled fast reactor, the evaluation of the safety performance and the determination of containment requirements may be worth considering due to the triple-fault accident sequences of extremely low probability of occurrence that leads to core melting. For any postulated accident sequence which leads to core melting, in-vessel retention of the core debris will be required as a design requirement for the future design of sodium cooled fast reactor. Also, proof of the capacity of the debris bed cooling is an essential condition to solve the problem of in-vessel retention of the core debris. Accordingly, evaluation of a packed debris bed cooling performance with single phase flow for demonstration sodium-cooled fast reactor was carried out for proof of the in-vessel retention of the core debris

  17. Analysis of High Temperature Reactor Control Rod Worth for the Initial and Full Core

    Science.gov (United States)

    Oktajianto, Hammam; Setiawati, Evi; Anam, Khoirul; Sugito, Heri

    2017-01-01

    Control rod is one important component in a nuclear reactor. In nuclear reactor operations the control rod functions to shut down the reactor. This research analyses ten control rods worth of HTR (High Temperature Reactor) at initial and full core. The HTR in this research adopts HTR-10 China and HTR- of pebble bed. Core calculations are performed by using MCNPX code after modelling the entire parts of core in condition of ten control rods fully withdrawn, all control rods in with 20 cm ranges of depth and the use of one control rod. Pebble bed and moderator balls are distributed in the core zone using a Body Centred Cubic (BCC) lattice by ratio of 57:43. The research results are obtained that the use of one control rod will decrease the reactor criticality of 2.04±0.12 %Δk/k at initial core and 1.57±0.10 %Δk/k at full core. The deeper control rods are in, the lesser criticality of reactor is with reactivity of ten control rods of 16.41±0.11 %Δk/k at initial core and 15.43±0.11 %Δk/k at full core. The results show that the use of ten control rods at full core will keep achieving subcritical condition even though the reactivity is smaller than reactivity at initial core.

  18. Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge.

    Science.gov (United States)

    Kimura, Yuki

    2002-09-01

    The lithic analysis of the Bed I and II assemblages from Olduvai Gorge reveals both static and dynamic time trends in early hominids' technology from 1.8 to 1.2 m.y.a. The Bed I Oldowan (1.87-1.75 m.y.a.) is characterized by the least effort strategy in terms of raw material exploitation and tool production. The inclusion of new raw material, chert, for toolmaking in the following Developed Oldowan A (DOA, 1.65-1.53 m.y.a.) facilitated more distinctive and variable flaking strategies depending on the kind of raw materials. The unique characters of DOA are explainable by this raw material factor, rather than technological development of hominids. The disappearance of chert in the subsequent Developed Oldowan B and Acheulian (1.53-1.2 m.y.a.) necessitated a shift in tool production strategy more similar to that of Bed I Oldowan than DOA. However, the evidence suggests that Bed II hominids might have been more skillful toolmakers, intensive tool-users, and engaged in more active transport of stone tools than the Bed I predecessors. Koobi Fora hominids maintained a more static tool-using behavior than their Olduvai counterparts due mainly to a stable supply of raw materials. They differed from Olduvai hominids in terms of less battering of cores, consistent transport behavior, and few productions of side-struck flakes, indicating a regional variation of toolmaking and using practice. However, they shared with Olduvai hominids a temporal trend toward the production of larger flakes from larger cores after 1.6 m.y.a. Increased intake of animal resources and the expansion of ranging area of Homo ergaster would have led to the development of technological organization. Technological changes in the Oldowan industry are attested at Olduvai Gorge, Koobi Fora, and Sterkfontein, suggesting that it was a pan-African synchronous phenomenon, beginning at 1.5 m.y.a.

  19. NONUNIFORM OPEN CHANNEL FLOW WITH UPWARD SEEPAGE THROUGH LOOSE BEDS

    Institute of Scientific and Technical Information of China (English)

    Subhasish DEY

    2003-01-01

    The Reynolds stress and bed shear stress are important parameters in fluvial hydraulics. Steadynonuniform flow in open channels with streamwise sloping beds having upward seepage through loose beds is theoretically analyzed to estimate the Reynolds stress and bed shear stress. Equations of the Reynolds stress and bed shear stress are developed, assuming a modified logarithmic velocity distribution law due to upward seepage, and using the Reynolds and continuity equations of twodimensional flow in open channels.

  20. Bed Stability and Debris Flow Erosion: A Dynamic "Shields Criterion" Associated with Bed Structure

    Science.gov (United States)

    Longjas, A.; Hill, K. M.

    2015-12-01

    Debris flows are mass movements that play an important role in transporting sediment from steep uplands to rivers at lower slopes. As the debris flow moves downstream, it entrains materials such as loose boulders, gravel, sand and mud deposited locally by shorter flows such as slides and rockfalls. To capture the conditions under which debris flows entrain bed sediment, some models use something akin to the Shields' criterion and an excess shear stress of the flow. However, these models typically neglect granular-scale effects in the bed which can modify the conditions under which a debris flow is erosional or depositional. For example, it is well known that repeated shearing causes denser packing in loose dry soils, which undoubtedly changes their resistance to shear. Here, we present laboratory flume experiments showing that the conditions for entrainment by debris flows is significantly dependent on the aging of an erodible bed even for narrowly distributed spherical particles. We investigate this quantitatively using particle tracking measurements to quantify instantaneous erosion rates and the evolving bed structure or "fabric". With progressive experiments we find a signature that emerges in the bed fabric that is correlated with an increasing apparent "fragility" of the bed. Specifically, a system that is originally depositional may become erosional after repeated debris flow events, and an erodible bed becomes increasingly erodible with repeated flows. We hypothesize that related effects of bed aging at the field scale may be partly responsible for the increasing destructiveness of secondary flows of landslides and debris flows.

  1. C. elegans BED domain transcription factor BED-3 controls lineage-specific cell proliferation during organogenesis.

    Science.gov (United States)

    Inoue, Takao; Sternberg, Paul W

    2010-02-15

    The control of cell division is critical to organogenesis, but how this control is achieved is not fully understood. We found that mutations in bed-3, encoding a BED Zn-finger domain transcription factor, confer a phenotype where a specific set of cell divisions during vulval organogenesis is lost. Unlike general cell cycle regulators in Caenorhabditis elegans, the function of bed-3 is restricted to specific lineages. Transcriptional reporters suggest that bed-3 is expressed in a limited number of cell types including vulval cells whose divisions are affected in bed-3 mutants. A bed-3 mutation also affects the expression pattern of the cdh-3 cadherin gene in the vulva. The phenotype of bed-3 mutants is similar to the phenotype caused by mutations in cog-1 (Nkx6), a component of a gene regulatory network controlling cell type specific gene expression in the vulval lineage. These results suggest that bed-3 is a key component linking the gene regulatory network controlling cell-type specification to control of cell division during vulval organogenesis.

  2. Thermal Analysis of Fluidized Bed and Fixed Bed Latent Heat Thermal Storage System

    Science.gov (United States)

    Beemkumar, N.; Karthikeyan, A.; Shiva Keshava Reddy, Kota; Rajesh, Kona; Anderson, A.

    2017-05-01

    Thermal energy storage technology is essential because its stores available energy at low cost. Objective of the work is to store the thermal energy in a most efficient method. This work is deal with thermal analysis of fluidized bed and fixed bed latent heat thermal storage (LHTS) system with different encapsulation materials (aluminium, brass and copper). D-Mannitol has been used as phase change material (PCM). Encapsulation material which is in orbicular shape with 4 inch diameter and 2 mm thickness orbicular shaped product is used. Therminol-66 is used as a heat transfer fluid (HTF). Arrangement of encapsulation material is done in two ways namely fluidized bed and fixed bed thermal storage system. Comparison was made between the performance of fixed bed and fluidized bed with different encapsulation material. It is observed that from the economical point of view aluminium in fluidized bed LHTS System has highest efficiency than copper and brass. The thermal energy storage system can be analyzed with fixed bed by varying mass flow rate of oil paves a way to find effective heat energy transfer.

  3. Application of CaO-Based Bed Material for Dual Fluidized Bed Steam Biomass Gasification

    Science.gov (United States)

    Koppatz, S.; Pfeifer, C.; Kreuzeder, A.; Soukup, G.; Hofbauer, H.

    Gasification of biomass is a suitable option for decentralized energy supply based on renewable sources in the range of up to 50 MW fuel input. The paper presents the dual fluidized bed (DFB) steam gasification process, which is applied to generate high quality and nitrogen-free product gas. Essential part of the DFB process is the bed material used in the fluidized reactors, which has significant impact on the product gas quality. By the use of catalytically active bed materials the performance of the overall process is increased, since the bed material favors reactions of the steam gasification. In particular, tar reforming reactions are favored. Within the paper, the pilot plant based on the DFB process with 100kW fuel input at Vienna University of Technology, Austria is presented. Actual investigations with focus on CaO-based bed materials (limestone) as well as with natural olivine as bed material were carried out at the pilot plant. The application of CaO-based bed material shows mainly decreased tar content in the product gas in contrast to experiments with olivine as bed material. The paper presents the results of steam gasification experiments with limestone and olivine, whereby the product gas composition as well as the tar content and the tar composition are outlined.

  4. Comparison of packed bed and fluidized bed membrane reactors for methane reforming

    NARCIS (Netherlands)

    Gallucci, Fausto; Sint Annaland, van Martin; Kuipers, J.A.M.

    2009-01-01

    In this work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, have been compared for the reforming of methane for the production of ultra-pure hydrogen. Using detailed theoretical models, the required membrane area to reach a given conversi

  5. Theoretical comparison of packed bed and fluidized bed membrane reactors for methane reforming

    NARCIS (Netherlands)

    Gallucci, Fausto; Sint Annaland, van Martin; Kuipers, J.A.M.

    2010-01-01

    In this theoretical work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, has been compared for ultra-pure hydrogen production via methane reforming. Using detailed theoretical models, the required membrane area to reach a given conversion

  6. IHI-FW circulating fluidized bed boiler

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S.; Omata, K.; Ishimoto, R.; Asai, M. (Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan))

    1993-07-01

    The technology and application of the circulating fluidized bed boiler (IHI-FW) are outlined. Circulating fluidized bed boilers have various features as compared with bubbling fluidized bed boilers as follows; a high combustion efficiency, efficient use of limestone for desulfurization, low NOx emission, adaptability to various fuels and capability to cope with load change. The IHI-FW boiler is furthermore featured by water-wall furnace of all-welded structure, water-cooled/steam cooled cyclone, and simple circulating system. The 30 t/h circulating fluidized bed boiler was introduced into the Tsu Works, Omikenshi Co., Ltd., Japan for private power generation. The boiler equipped with a backup heavy oil burner mainly uses semi-anthracite coal, and besides sulfur capture and NOx reduction functions of a bed, a bag filter with a high dust collecting efficiency is installed in an exhaust gas system. The installation period was reduced to 2.5 months, a half of conventional ones, by more assembly in a factory followed by less field works. 7 figs., 2 tabs.

  7. Wear prediction in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, E.J. [USDOE Morgantown Energy Technology Center, WV (United States); Rogers, W.A. [EG and G Washington Analytical Services Center, Inc., Morgantown, WV (United States)

    1993-06-01

    A procedure to model the wear of surfaces exposed to a fluidized bed is formulated. A stochastic methodology adapting the kinetic theory of gases to granular flows is used to develop an impact wear model. This uses a single-particle wear model to account for impact wear from all possible-particle collisions. An adaptation of a single-particle abrasion model to describe the effects of many abrading particles is used to account for abrasive wear. Parameters describing granular flow within the fluidized bed, necessary for evaluation of the wear expressions, are determined by numerical solution of the fluidized bed hydrodynamic equations. Additional parameters, describing the contact between fluidized particles and the wearing surface, are determined by optimization based on wear measurements. The modeling procedure was used to analyze several bubbling and turbulent fluidized bed experiments with single-tube and tube bundle configurations. Quantitative agreement between the measured and predicted wear rates was found, with some exceptions for local wear predictions. This work demonstrates a methodology for wear predictions in fluidized beds.

  8. Grain Exchange Probabilities Within a Gravel Bed

    Science.gov (United States)

    Haschenburger, J.

    2008-12-01

    Sediment transfers in gravel-bed rivers involve the vertical exchange of sediments during floods. These exchanges regulate the virtual velocity of sediment and bed material texture. This study describes general tendencies in the vertical exchange of gravels within the substrate that result from multiple floods. Empirical observations come from Carnation Creek, a small gravel-bed river with large woody debris located on the west coast of Vancouver Island, British Columbia. Frequent floods and the relatively limited armor layer facilitate streambed activity and relatively high bedload transport rates, typically under partial sediment transport conditions. Over 2000 magnetically tagged stones, ranging in size from 16 to 180 mm, were deployed on the bed surface between 1991 and 1992. These tracers have been recovered 10 times over 12 flood seasons to quantify their vertical position in the streambed. For analysis, the bed is divided into layers based on armor layer thickness. Once tracers are well mixed within the streambed, grains in the surface layer are most likely to be mixed into the subsurface, while subsurface grains are most likely to persist within the subsurface. Fractional exchange probabilities approach size independence when the most active depth of the substrate is considered. Overall these results highlight vertical mixing as an important process in the dispersion of gravels.

  9. Nonlinear Mechanism of Bed Load Transport

    Institute of Scientific and Technical Information of China (English)

    XU Haijue; BAI Yuchuan; NG Chiu-On

    2009-01-01

    From the group movement of the bed load within the bottom layer, details of the nonlinear dynamic characteristics of bed load movement are discussed in this paper. Whether the sediment is initiated into motion cor-responds to whether the constant term in the equation is equal to zero. If constant term is zero and no dispersive force is considered, the equation represents the traditional Shields initiation curve, and if constant term is zero with-out the dispersive force being considered, then a new Shields curve which is much lower than the traditional one is got, The fixed point of the equation corresponds to the equilibrium sediment transport of bed load. In the mutation analysis, we have found that the inflection point is the demarcation point of breaking. In theory, the breaking point corresponds to the dividing boundary line, across which the bed form changes from flat bed to sand ripple or sand dune. Compared with the experimental data of Chatou Hydraulic Lab in France, the conclusions are verified.

  10. Measurement of powder bed density in powder bed fusion additive manufacturing processes

    Science.gov (United States)

    Jacob, G.; Donmez, A.; Slotwinski, J.; Moylan, S.

    2016-11-01

    Many factors influence the performance of additive manufacturing (AM) processes, resulting in a high degree of variation in process outcomes. Therefore, quantifying these factors and their correlations to process outcomes are important challenges to overcome to enable widespread adoption of emerging AM technologies. In the powder bed fusion AM process, the density of the powder layers in the powder bed is a key influencing factor. This paper introduces a method to determine the powder bed density (PBD) during the powder bed fusion (PBF) process. A complete uncertainty analysis associated with the measurement method was also described. The resulting expanded measurement uncertainty, U PBD (k  =  2), was determined as 0.004 g · cm-3. It was shown that this expanded measurement uncertainty is about three orders of magnitude smaller than the typical powder bed density. This method enables establishing correlations between the changes in PBD and the direction of motion of the powder recoating arm.

  11. Analytical results from samples collected during coal-bed methane exploration drilling in Caldwell Parish, Louisiana

    Science.gov (United States)

    Warwick, Peter D.; Breland, F. Clayton; Hackley, Paul C.; Dulong, Frank T.; Nichols, Douglas J.; Karlsen, Alexander W.; Bustin, R. Marc; Barker, Charles E.; Willett, Jason C.; Trippi, Michael H.

    2006-01-01

    In 2001, and 2002, the U.S. Geological Survey (USGS) and the Louisiana Geological Survey (LGS), through a Cooperative Research and Development Agreement (CRADA) with Devon SFS Operating, Inc. (Devon), participated in an exploratory drilling and coring program for coal-bed methane in north-central Louisiana. The USGS and LGS collected 25 coal core and cuttings samples from two coal-bed methane test wells that were drilled in west-central Caldwell Parish, Louisiana. The purpose of this report is to provide the results of the analytical program conducted on the USGS/LGS samples. The data generated from this project are summarized in various topical sections that include: 1. molecular and isotopic data from coal gas samples; 2. results of low-temperature ashing and X-ray analysis; 3. palynological data; 4. down-hole temperature data; 5. detailed core descriptions and selected core photographs; 6. coal physical and chemical analytical data; 7. coal gas desorption results; 8. methane and carbon dioxide coal sorption data; 9. coal petrographic results; and 10. geophysical logs.

  12. Analysis of Fluid Flow and Heat Transfer Model for the Pebble Bed High Temperature Gas Cooled Reactor

    Directory of Open Access Journals (Sweden)

    S. Yamoah

    2012-06-01

    Full Text Available The pebble bed type high temperature gas cooled nuclear reactor is a promising option for next generation reactor technology and has the potential to provide high efficiency and cost effective electricity generation. The reactor unit heat transfer poses a challenge due to the complexity associated with the thermalflow design. Therefore to reliably simulate the flow and heat transport of the pebble bed modular reactor necessitates a heat transfer model that deals with radiation as well as thermal convection and conduction. In this study, a model with the capability to simulate fluid flow and heat transfer in the pebble bed modular reactor core has been developed. The developed model was implemented on a personal computer using FORTRAN 95 programming language. Several important fluid flow and heat transfer parameters have been examined: including the pressure drop over the reactor core, the heat transfer coefficient, the Nusselt number and the effective thermal conductivity of the fuel pebbles. Results obtained from the simulation experiments show a uniform pressure in the radial direction for a core to fuel element diameter (D/d ratio>20 and the heat transfer coefficient increases with increasing temperature and coolant mass flow rate. The model can adequately account for the flow and heat transfer phenomenon and the loss of pressure through friction in the pebble bed type high temperature nuclear reactor.

  13. Ice Core Investigations

    Science.gov (United States)

    Krim, Jessica; Brody, Michael

    2008-01-01

    What can glaciers tell us about volcanoes and atmospheric conditions? How does this information relate to our understanding of climate change? Ice Core Investigations is an original and innovative activity that explores these types of questions. It brings together popular science issues such as research, climate change, ice core drilling, and air…

  14. Making an Ice Core.

    Science.gov (United States)

    Kopaska-Merkel, David C.

    1995-01-01

    Explains an activity in which students construct a simulated ice core. Materials required include only a freezer, food coloring, a bottle, and water. This hands-on exercise demonstrates how a glacier is formed, how ice cores are studied, and the nature of precision and accuracy in measurement. Suitable for grades three through eight. (Author/PVD)

  15. Ice Core Investigations

    Science.gov (United States)

    Krim, Jessica; Brody, Michael

    2008-01-01

    What can glaciers tell us about volcanoes and atmospheric conditions? How does this information relate to our understanding of climate change? Ice Core Investigations is an original and innovative activity that explores these types of questions. It brings together popular science issues such as research, climate change, ice core drilling, and air…

  16. Iowa Core Annual Report

    Science.gov (United States)

    Iowa Department of Education, 2015

    2015-01-01

    One central component of a great school system is a clear set of expectations, or standards, that educators help all students reach. In Iowa, that effort is known as the Iowa Core. The Iowa Core represents the statewide academic standards, which describe what students should know and be able to do in math, science, English language arts, and…

  17. Mercury's core evolution

    Science.gov (United States)

    Deproost, Marie-Hélène; Rivoldini, Attilio; Van Hoolst, Tim

    2016-10-01

    Remote sensing data of Mercury's surface by MESSENGER indicate that Mercury formed under reducing conditions. As a consequence, silicon is likely the main light element in the core together with a possible small fraction of sulfur. Compared to sulfur, which does almost not partition into solid iron at Mercury's core conditions and strongly decreases the melting temperature, silicon partitions almost equally well between solid and liquid iron and is not very effective at reducing the melting temperature of iron. Silicon as the major light element constituent instead of sulfur therefore implies a significantly higher core liquidus temperature and a decrease in the vigor of compositional convection generated by the release of light elements upon inner core formation.Due to the immiscibility in liquid Fe-Si-S at low pressure (below 15 GPa), the core might also not be homogeneous and consist of an inner S-poor Fe-Si core below a thinner Si-poor Fe-S layer. Here, we study the consequences of a silicon-rich core and the effect of the blanketing Fe-S layer on the thermal evolution of Mercury's core and on the generation of a magnetic field.

  18. Reservoir evaluation of thin-bedded turbidites and hydrocarbon pore thickness estimation for an accurate quantification of resource

    Science.gov (United States)

    Omoniyi, Bayonle; Stow, Dorrik

    2016-04-01

    One of the major challenges in the assessment of and production from turbidite reservoirs is to take full account of thin and medium-bedded turbidites (succession, they can go unnoticed by conventional analysis and so negatively impact on reserve estimation, particularly in fields producing from prolific thick-bedded turbidite reservoirs. Field development plans often take little note of such thin beds, which are therefore bypassed by mainstream production. In fact, the trapped and bypassed fluids can be vital where maximising field value and optimising production are key business drivers. We have studied in detail, a succession of thin-bedded turbidites associated with thicker-bedded reservoir facies in the North Brae Field, UKCS, using a combination of conventional logs and cores to assess the significance of thin-bedded turbidites in computing hydrocarbon pore thickness (HPT). This quantity, being an indirect measure of thickness, is critical for an accurate estimation of original-oil-in-place (OOIP). By using a combination of conventional and unconventional logging analysis techniques, we obtain three different results for the reservoir intervals studied. These results include estimated net sand thickness, average sand thickness, and their distribution trend within a 3D structural grid. The net sand thickness varies from 205 to 380 ft, and HPT ranges from 21.53 to 39.90 ft. We observe that an integrated approach (neutron-density cross plots conditioned to cores) to HPT quantification reduces the associated uncertainties significantly, resulting in estimation of 96% of actual HPT. Further work will focus on assessing the 3D dynamic connectivity of the low-pay sands with the surrounding thick-bedded turbidite facies.

  19. Mars' core and magnetism.

    Science.gov (United States)

    Stevenson, D J

    2001-07-12

    The detection of strongly magnetized ancient crust on Mars is one of the most surprising outcomes of recent Mars exploration, and provides important insight about the history and nature of the martian core. The iron-rich core probably formed during the hot accretion of Mars approximately 4.5 billion years ago and subsequently cooled at a rate dictated by the overlying mantle. A core dynamo operated much like Earth's current dynamo, but was probably limited in duration to several hundred million years. The early demise of the dynamo could have arisen through a change in the cooling rate of the mantle, or even a switch in convective style that led to mantle heating. Presently, Mars probably has a liquid, conductive outer core and might have a solid inner core like Earth.

  20. Neurogenetic and morphogenetic heterogeneity in the bed nucleus of the stria terminalis

    Energy Technology Data Exchange (ETDEWEB)

    Bayer, S.A.

    1987-11-01

    Neurogenesis and morphogenesis in the rat bed nucleus of the stria terminalis (strial bed nucleus) were examined with (/sup 3/H)thymidine autoradiography. For neurogenesis, the experimental animals were the offspring of pregnant females given an injection of (/sup 3/H)thymidine on 2 consecutive gestational days. Nine groups of embryos were exposed to (/sup 3/H)thymidine on E13-E14, E14-E15,... E21-E22, respectively. On P60, the percentage of labeled cells and the proportion of cells originating during 24-hour periods were quantified at six anteroposterior levels in the strial bed nucleus. On the basis of neurogenetic gradients, the strial bed nucleus was divided into anterior and posterior parts. The anterior strial bed nucleus shows a caudal (older) to rostral (younger) neurogenetic gradient. Cells in the vicinity of the anterior commissural decussation are generated mainly between E13 and E16, cells just posterior to the nucleus accumbens mainly between E15 and E17. Within each rostrocaudal level, neurons originate in combined dorsal to ventral and medial to lateral neurogenetic gradients so that the oldest cells are located ventromedially and the youngest cells dorsolaterally. The most caudal level has some small neurons adjacent to the internal capsule that originate between E17 and E20. In the posterior strial bed nucleus, neurons extend ventromedially into the posterior preoptic area. Cells are generated simultaneously along the rostrocaudal plane in a modified lateral (older) to medial (younger) neurogenetic gradient. Ventrolateral neurons originate mainly between E13 and E16, dorsolateral neurons mainly between E15 and E16, and medial neurons mainly between E15 and E17. The youngest neurons are clumped into a medial core area just ventral to the fornix.

  1. Rock bed heat accumulators. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Riaz, M.

    1977-12-01

    The principal objectives of the research program on rock bed heat accumulators (or RBHA) are: (1) to investigate the technical and economic feasibility of storing large amounts of thermal energy (in the tens of MWt range) at high temperature (up to 500/sup 0/C) over extended periods of time (up to 6 months) using native earth or rock materials; (2) to conduct studies to establish the performance characteristics of large rock bed heat accumulators at various power and temperature levels compatible with thermal conversion systems; and (3) to assess the materials and environmental problems associated with the operation of such large heat accumulators. Results of the study indicate that rock bed heat accumulators for seasonal storage are both technically and economically feasible, and hence could be exploited in various applications in which storage plays an essential role such as solar power and total energy systems, district and cogeneration heating systems.

  2. Methane desorption from a coal-bed

    Energy Technology Data Exchange (ETDEWEB)

    A.D. Alexeev; E.P. Feldman; T.A. Vasilenko [National Academy of Sciences of Ukraine, Donetsk (Ukraine). Donetsk Institute for Physics of Mining Processes

    2007-11-15

    We study the desorption of methane from a coal-bed. A model taking into account both methane diffusion in coal-blocks and its filtration through the system of open pores and cracks is developed. Methane pressure in the coal-bed is found for an arbitrary instant of time. Dependency of the rate of methane release upon the block size, open and closed porosity, viscosity, solubility, bed pressure and temperature is established. We derive the effective coefficient of diffusion of methane in blocks containing closed pores filled with gaseous methane. It is shown that at a hindered diffusion methane is distinctly divided into the 'quick' and the 'slow' one. 25 refs., 5 figs.

  3. Magnetohydrodynamic Flow Past a Permeable Bed

    Directory of Open Access Journals (Sweden)

    R. Venugopal

    1983-01-01

    Full Text Available The paper evaluates mass flow velocity heat transfer rates and velocity/temperature distributions in the viscous, incompressible and slightly conducting fluid past a permeable bed in three different configurations namely (1 Couette flow (2 Poiseuille flow and (3 free surface flow, under the influence of a uniform transverse magnetic field. To discuss the solution, the flow region is divided into two zones : Zone 1 (from the impermeable upper rigid plate to the permeable bed in which the flow is laminar and governed by Navier-Stokes equations, and Zone 2 (the permeable bed below the nominal surface in which the flow is governed by Darcy law. The paper also investigates the effects of magnetic field, porosity and Biot number on the physical quantities mentioned above.

  4. Tube erosion in bubbling fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Levy, E.K. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center; Stallings, J.W. [Electric Power Research Inst., Palo Alto, CA (United States)

    1991-12-31

    This paper reports on experimental and theoretical studies that were preformed of the interaction between bubbles and tubes and tube erosion in fluidized beds. The results are applicable to the erosion of horizontal tubes in the bottom row of a tube bundle in a bubbling bed. Cold model experimental data show that erosion is caused by the impact of bubble wakes on the tubes, with the rate of erosion increasing with the velocity of wake impact with the particle size. Wake impacts resulting from the vertical coalescence of pairs of bubbles directly beneath the tube result in particularly high rates of erosion damage. Theoretical results from a computer simulation of bubbling and erosion show very strong effects of the bed geometry and bubbling conditions on computed rates of erosion. These results show, for example, that the rate of erosion can be very sensitive to the vertical location of the bottom row of tubes with respect to the distributor.

  5. A safety re-evaluation of the AVR pebble bed reactor operation and its consequences for future HTR concepts

    Energy Technology Data Exchange (ETDEWEB)

    Moormann, R.

    2008-06-15

    The AVR pebble bed reactor (46 MW{sub th}) was operated 1967-88 at coolant outlet temperatures up to 990 C. A principle difference of pebble bed HTRs as AVR to conventional reactors is the continuous movement of fuel element pebbles through the core which complicates thermohydraulic, nuclear and safety estimations. Also because of a lack of other experience AVR operation is still a relevant basis for future pebble bed HTRs and thus requires careful examination. This paper deals mainly with some insufficiently published unresolved safety problems of AVR operation and of pebble bed HTRs but skips the widely known advantageous features of pebble bed HTRs. The AVR primary circuit is heavily contaminated with metallic fission products (Sr-90, Cs-137) which create problems in current dismantling. The amount of this contamination is not exactly known, but the evaluation of fission product deposition experiments indicates that the end of life contamination reached several percent of a single core inventory, which is some orders of magnitude more than precalculated and far more than in large LWRs. A major fraction of this contamination is bound on graphitic dust and thus partly mobile in depressurization accidents, which has to be considered in safety analyses of future reactors. A re-evaluation of the AVR contamination is performed here in order to quantify consequences for future HTRs (400 MW{sub th}). It leads to the conclusion that the AVR contamination was mainly caused by inadmissible high core temperatures, increasing fission product release rates, and not - as presumed in the past - by inadequate fuel quality only. The high AVR core temperatures were detected not earlier than one year before final AVR shut-down, because a pebble bed core cannot yet be equipped with instruments. The maximum core temperatures are still unknown but were more than 200 K higher than calculated. Further, azimuthal temperature differences at the active core margin of up to 200 K were

  6. Novel Simulated moving bed technologies

    Energy Technology Data Exchange (ETDEWEB)

    Purdue University

    2003-12-30

    Cellulose and hemicellulose from plants and other biomass can be hydrolyzed to produce sugars (i.e. glucose and xylose). Once these sugars are separated from other impurities, they can serve as feedstock in fermentation to produce ethanol (as fuels), lactic acid, or other valuable chemicals. The need for producing fuels and chemicals from renewable biomass has become abundantly clear over the last decade. However, the cost of producing fermentable sugars from biomass hydrolyzate using existing technology is relatively high and has been a major obstacle. The objective of this project is to develop an efficient and economical simulated moving bed (SMB) process to recover fermentable sugars from biomass hydrolyzate. Sulfuric acid can hydrolyze the cellulose and hemicellulose in biomass to sugars, but this process can generate byproducts such as acetic acid, and can lead to further degradation of the xylose to furfural and glucose to hydroxymethyl furfural (HMF). Also, lignin and other compounds in the biomass will degrade to various phenolic compounds. If the concentrations of these compounds exceed certain threshold levels, they will be toxic to the downstream fermentation, and will severely limit the usefulness of the derived sugars. Standard post-hydrolysis processing involves neutralization of sulfuric acid, usually with lime (calcium hydroxide). A study by Wooley et al.showed that the limed hydrolyzate gave a low ethanol yield in fermentation test (20% of theoretical yield compared to 77% of theoretical yield from fermentation of pure sugars). They showed that instead of adding lime, an ion exclusion chromatography process could be used to remove acids, as well as to isolate the sugars from the biomass hydrolyzate. In this project, we investigated the feasibility of developing an economical SMB process based on (1) a polymeric adsorbent, Dowex99, which was used by Wooley et al., (2) a second polymeric adsorbent, poly-4-vinyl pyridine (or PVP in short, Reilly

  7. Novel Simulated moving bed technologies

    Energy Technology Data Exchange (ETDEWEB)

    Purdue University

    2003-12-30

    Cellulose and hemicellulose from plants and other biomass can be hydrolyzed to produce sugars (i.e. glucose and xylose). Once these sugars are separated from other impurities, they can serve as feedstock in fermentation to produce ethanol (as fuels), lactic acid, or other valuable chemicals. The need for producing fuels and chemicals from renewable biomass has become abundantly clear over the last decade. However, the cost of producing fermentable sugars from biomass hydrolyzate using existing technology is relatively high and has been a major obstacle. The objective of this project is to develop an efficient and economical simulated moving bed (SMB) process to recover fermentable sugars from biomass hydrolyzate. Sulfuric acid can hydrolyze the cellulose and hemicellulose in biomass to sugars, but this process can generate byproducts such as acetic acid, and can lead to further degradation of the xylose to furfural and glucose to hydroxymethyl furfural (HMF). Also, lignin and other compounds in the biomass will degrade to various phenolic compounds. If the concentrations of these compounds exceed certain threshold levels, they will be toxic to the downstream fermentation, and will severely limit the usefulness of the derived sugars. Standard post-hydrolysis processing involves neutralization of sulfuric acid, usually with lime (calcium hydroxide). A study by Wooley et al.showed that the limed hydrolyzate gave a low ethanol yield in fermentation test (20% of theoretical yield compared to 77% of theoretical yield from fermentation of pure sugars). They showed that instead of adding lime, an ion exclusion chromatography process could be used to remove acids, as well as to isolate the sugars from the biomass hydrolyzate. In this project, we investigated the feasibility of developing an economical SMB process based on (1) a polymeric adsorbent, Dowex99, which was used by Wooley et al., (2) a second polymeric adsorbent, poly-4-vinyl pyridine (or PVP in short, Reilly

  8. Exercise countermeasures for bed-rest deconditioning

    Science.gov (United States)

    Greenleaf, John (Editor)

    1993-01-01

    The purpose for this 30-day bed rest study was to investigate the effects of short-term, high intensity isotonic and isokinetic exercise training on maintenance of working capacity (peak oxygen uptake), muscular strength and endurance, and on orthostatic tolerance, posture and gait. Other data were collected on muscle atrophy, bone mineralization and density, endocrine analyses concerning vasoactivity and fluid-electrolyte balance, muscle intermediary metabolism, and on performance and mood of the subjects. It was concluded that: The subjects maintained a relatively stable mood, high morale, and high esprit de corps throughout the study. Performance improved in nearly all tests in almost all the subjects. Isotonic training, as opposed to isokinetic exercise training, was associated more with decreasing levels of psychological tension, concentration, and motivation; and improvement in the quality of sleep. Working capacity (peak oxygen uptake) was maintained during bed rest with isotonic exercise training; it was not maintained with isokinetic or no exercise training. In general, there was no significant decrease in strength or endurance of arm or leg muscles during bed rest, in spite of some reduction in muscle size (atrophy) of some leg muscles. There was no effect of isotonic exercise training on orthostasis, since tilt-table tolerance was reduced similarly in all three groups following bed rest. Bed rest resulted in significant decreases of postural stability and self-selected step length, stride length, and walking velocity, which were not influenced by either exercise training regimen. Most pre-bed rest responses were restored by the fourth day of recovery.

  9. Forecasting of the content of the insoluble residue in clay layers of productive beds of the Verkhnekamskoe salt deposit

    Directory of Open Access Journals (Sweden)

    E. O. Bayandina

    2015-03-01

    Full Text Available Using data from the exploration drilling at the mines BKPRU-2 and BKPRU-3 of JSC Uralkali, the relationship equations between the content of insoluble residue in the productive sylvinite beds and thick interbedded clay layers at their top referred to as «korjʼs» are worked out. Knowledge of composition and thickness of clay layers is very important for rockfall protection during mining work. The results of analysis of drilling data are often not reliable because of the losses of clay material in the extracted core. The resulting equations are recommended for forecastingof insoluble residue in «korjʼs» of those beds.

  10. The t-core of an s-core

    OpenAIRE

    Fayers, Matthew

    2010-01-01

    We consider the $t$-core of an $s$-core partition, when $s$ and $t$ are coprime positive integers. Olsson has shown that the $t$-core of an $s$-core is again an $s$-core, and we examine certain actions of the affine symmetric group on $s$-cores which preserve the $t$-core of an $s$-core. Along the way, we give a new proof of Olsson's result. We also give a new proof of a result of Vandehey, showing that there is a simultaneous $s$- and $t$-core which contains all others.

  11. The t-core of an s-core

    OpenAIRE

    Fayers, Matthew

    2010-01-01

    We consider the $t$-core of an $s$-core partition, when $s$ and $t$ are coprime positive integers. Olsson has shown that the $t$-core of an $s$-core is again an $s$-core, and we examine certain actions of the affine symmetric group on $s$-cores which preserve the $t$-core of an $s$-core. Along the way, we give a new proof of Olsson's result. We also give a new proof of a result of Vandehey, showing that there is a simultaneous $s$- and $t$-core which contains all others.

  12. Development of a hover test bed

    Science.gov (United States)

    Williams, Jason Alan

    This research examines the development, validation, and verification of a hover test bed at the Missile Defense Agency's National Hover Test Facility located at the Air Force Research Laboratory on Edwards Air Force Base, California. This work's scope includes the development of a test bed for exoatmospheric kill vehicle testing in an integrated hover test arrangement. The approach involved reactivation of the facility, design of a risk reduction methodology, and vehicle performance verification. Details from a combustion stability issue on the divert engine is investigated, and changing the diameter of the injector reduced a first tangential combustion chamber mode combustion instability from 17.8% to 0.8%.

  13. Cardiac atrophy after bed rest and spaceflight

    Science.gov (United States)

    Perhonen, M. A.; Franco, F.; Lane, L. D.; Buckey, J. C.; Blomqvist, C. G.; Zerwekh, J. E.; Peshock, R. M.; Weatherall, P. T.; Levine, B. D.

    2001-01-01

    Cardiac muscle adapts well to changes in loading conditions. For example, left ventricular (LV) hypertrophy may be induced physiologically (via exercise training) or pathologically (via hypertension or valvular heart disease). If hypertension is treated, LV hypertrophy regresses, suggesting a sensitivity to LV work. However, whether physical inactivity in nonathletic populations causes adaptive changes in LV mass or even frank atrophy is not clear. We exposed previously sedentary men to 6 (n = 5) and 12 (n = 3) wk of horizontal bed rest. LV and right ventricular (RV) mass and end-diastolic volume were measured using cine magnetic resonance imaging (MRI) at 2, 6, and 12 wk of bed rest; five healthy men were also studied before and after at least 6 wk of routine daily activities as controls. In addition, four astronauts were exposed to the complete elimination of hydrostatic gradients during a spaceflight of 10 days. During bed rest, LV mass decreased by 8.0 +/- 2.2% (P = 0.005) after 6 wk with an additional atrophy of 7.6 +/- 2.3% in the subjects who remained in bed for 12 wk; there was no change in LV mass for the control subjects (153.0 +/- 12.2 vs. 153.4 +/- 12.1 g, P = 0.81). Mean wall thickness decreased (4 +/- 2.5%, P = 0.01) after 6 wk of bed rest associated with the decrease in LV mass, suggesting a physiological remodeling with respect to altered load. LV end-diastolic volume decreased by 14 +/- 1.7% (P = 0.002) after 2 wk of bed rest and changed minimally thereafter. After 6 wk of bed rest, RV free wall mass decreased by 10 +/- 2.7% (P = 0.06) and RV end-diastolic volume by 16 +/- 7.9% (P = 0.06). After spaceflight, LV mass decreased by 12 +/- 6.9% (P = 0.07). In conclusion, cardiac atrophy occurs during prolonged (6 wk) horizontal bed rest and may also occur after short-term spaceflight. We suggest that cardiac atrophy is due to a physiological adaptation to reduced myocardial load and work in real or simulated microgravity and demonstrates the plasticity

  14. Cardiac atrophy after bed rest and spaceflight

    Science.gov (United States)

    Perhonen, M. A.; Franco, F.; Lane, L. D.; Buckey, J. C.; Blomqvist, C. G.; Zerwekh, J. E.; Peshock, R. M.; Weatherall, P. T.; Levine, B. D.

    2001-01-01

    Cardiac muscle adapts well to changes in loading conditions. For example, left ventricular (LV) hypertrophy may be induced physiologically (via exercise training) or pathologically (via hypertension or valvular heart disease). If hypertension is treated, LV hypertrophy regresses, suggesting a sensitivity to LV work. However, whether physical inactivity in nonathletic populations causes adaptive changes in LV mass or even frank atrophy is not clear. We exposed previously sedentary men to 6 (n = 5) and 12 (n = 3) wk of horizontal bed rest. LV and right ventricular (RV) mass and end-diastolic volume were measured using cine magnetic resonance imaging (MRI) at 2, 6, and 12 wk of bed rest; five healthy men were also studied before and after at least 6 wk of routine daily activities as controls. In addition, four astronauts were exposed to the complete elimination of hydrostatic gradients during a spaceflight of 10 days. During bed rest, LV mass decreased by 8.0 +/- 2.2% (P = 0.005) after 6 wk with an additional atrophy of 7.6 +/- 2.3% in the subjects who remained in bed for 12 wk; there was no change in LV mass for the control subjects (153.0 +/- 12.2 vs. 153.4 +/- 12.1 g, P = 0.81). Mean wall thickness decreased (4 +/- 2.5%, P = 0.01) after 6 wk of bed rest associated with the decrease in LV mass, suggesting a physiological remodeling with respect to altered load. LV end-diastolic volume decreased by 14 +/- 1.7% (P = 0.002) after 2 wk of bed rest and changed minimally thereafter. After 6 wk of bed rest, RV free wall mass decreased by 10 +/- 2.7% (P = 0.06) and RV end-diastolic volume by 16 +/- 7.9% (P = 0.06). After spaceflight, LV mass decreased by 12 +/- 6.9% (P = 0.07). In conclusion, cardiac atrophy occurs during prolonged (6 wk) horizontal bed rest and may also occur after short-term spaceflight. We suggest that cardiac atrophy is due to a physiological adaptation to reduced myocardial load and work in real or simulated microgravity and demonstrates the plasticity

  15. South Africa slashes pebble-bed cash

    Science.gov (United States)

    Cartlidge, Edwin

    2010-04-01

    A novel modular technology that promised to make nuclear power cheaper and safer has suffered a serious blow following withdrawal of support from the South African government. It decided not to renew funding for the pebble-bed modular reactor beyond 31 March this year following a lack of interest from other investors and no customers for its product. The company developing the reactor concept - Pebble Bed Modular Reactor Ltd (PBMR) - is to axe three-quarters of its roughly 800 staff and its chief executive has resigned.

  16. Lake bed classification using acoustic data

    Science.gov (United States)

    Yin, Karen K.; Li, Xing; Bonde, John; Richards, Carl; Cholwek, Gary

    1998-01-01

    As part of our effort to identify the lake bed surficial substrates using remote sensing data, this work designs pattern classifiers by multivariate statistical methods. Probability distribution of the preprocessed acoustic signal is analyzed first. A confidence region approach is then adopted to improve the design of the existing classifier. A technique for further isolation is proposed which minimizes the expected loss from misclassification. The devices constructed are applicable for real-time lake bed categorization. A mimimax approach is suggested to treat more general cases where the a priori probability distribution of the substrate types is unknown. Comparison of the suggested methods with the traditional likelihood ratio tests is discussed.

  17. Korrelasjon mellom core styrke, core stabilitet og utholdende styrke i core

    OpenAIRE

    Berg-Olsen, Andrea Marie; Fugelsøy, Eivor; Maurstad, Ann-Louise

    2010-01-01

    Formålet med studien var å se hvilke korrelasjon det er mellom core styrke, core stabilitet og utholdende styrke i core. Testingen bestod av tre hoveddeler hvor vi testet core styrke, core stabilitet og utholdende styrke i core. Innenfor core styrke og utholdende styrke i core ble tre ulike tester utført. Ved måling av core stabilitet ble det gjennomført kun en test. I core styrke ble isometrisk abdominal fleksjon, isometrisk rygg ekstensjon og isometrisk lateral fleksjon testet. Sit-ups p...

  18. Korrelasjon mellom core styrke, core stabilitet og utholdende styrke i core

    OpenAIRE

    Berg-Olsen, Andrea Marie; Fugelsøy, Eivor; Maurstad, Ann-Louise

    2010-01-01

    Formålet med studien var å se hvilke korrelasjon det er mellom core styrke, core stabilitet og utholdende styrke i core. Testingen bestod av tre hoveddeler hvor vi testet core styrke, core stabilitet og utholdende styrke i core. Innenfor core styrke og utholdende styrke i core ble tre ulike tester utført. Ved måling av core stabilitet ble det gjennomført kun en test. I core styrke ble isometrisk abdominal fleksjon, isometrisk rygg ekstensjon og isometrisk lateral fleksjon testet. Sit-ups p...

  19. Earth's inner core: Innermost inner core or hemispherical variations?

    NARCIS (Netherlands)

    Lythgoe, K. H.; Deuss, A.; Rudge, J. F.; Neufeld, J. A.

    2014-01-01

    The structure of Earth's deep inner core has important implications for core evolution, since it is thought to be related to the early stages of core formation. Previous studies have suggested that there exists an innermost inner core with distinct anisotropy relative to the rest of the inner core.

  20. Earth's inner core: Innermost inner core or hemispherical variations?

    NARCIS (Netherlands)

    Lythgoe, K. H.; Deuss, A.; Rudge, J. F.; Neufeld, J. A.

    2014-01-01

    The structure of Earth's deep inner core has important implications for core evolution, since it is thought to be related to the early stages of core formation. Previous studies have suggested that there exists an innermost inner core with distinct anisotropy relative to the rest of the inner core.

  1. Critical conditions of bed sediment entrainment due to debris flow

    Directory of Open Access Journals (Sweden)

    M. Papa

    2004-01-01

    Full Text Available The present study describes entrainment characteristics of bed material into debris flow, based on flume tests, numerical and dimensional analyses. Flume tests are conducted to investigate influences of bed sediment size on erosion rate by supplying debris flows having unsaturated sediment concentration over erodible beds. Experimental results show that the erosion rate decreases monotonically with increase of sediment size, although erosion rate changes with sediment concentration of debris flow body. In order to evaluate critical condition of bed sediment entrainment, a length scale which measures an effective bed shear stress is introduced. The effective bed shear stress is defined as total shear stress minus yield stress on the bed surface. The results show that critical entrainment conditions can be evaluated well in terms of Shields curve using the effective bed shear stress instead of a usual bed shear stress.

  2. Perspectives for Fluidized Bed Nuclear Reactor Technology using Rotating Fluidized Beds in a Static Geometry

    Science.gov (United States)

    Broqueville, Axel De; Wilde, Juray De

    The new concept of a rotating fluidized bed in a static geometry opens perspectives for fluidized bed nuclear reactor technology and is experimentally and numerically investigated. With conventional fluidized bed technology, the maximum attainable power is rather limited and maximum at a certain fluidization gas flow rate. Using a rotating fluidized bed in a static geometry, the fluidization gas drives both the centrifugal force and the counteracting radial gas-solid drag force in a similar way. This allows operating the reactor at any chosen sufficiently high solids loading over a much wider fluidization gas flow rate range and in particular at much higher fluidization gas flow rates than with conventional fluidized bed reactor technology, offering increased flexibility with respect to cooling via the fluidization gas. Furthermore, the centrifugal force can be a multiple of earth gravity, allowing radial gas-solid slip velocities much higher than in conventional fluidized beds. The latter result in gas-solid heat transfer coefficients one or multiple orders of magnitude higher than in conventional fluidized beds. The combination of dense operation and high fluidization gas flow rates allows process intensification and a more compact reactor design.

  3. Loading and Unloading Weaned Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture

    Directory of Open Access Journals (Sweden)

    Arlene Garcia

    2014-12-01

    Full Text Available The use of non-slip surfaces during loading and unloading of weaned pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps below 20° to load and unload pigs. Three ramp angles (0°, 10° or 20°, five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay, two moistures (dry or wet bedding; >50% moisture over two seasons (>23.9 °C summer, <23.9 °C winter were assessed for slips/falls/vocalizations (n = 6,000 pig observations. “Score” was calculated by the sum of slips, falls, and vocalizations. With the exception of using feed as a bedding, all beddings provided some protection against elevated slips, falls, and vocalizations (P < 0.01. Providing bedding reduced (P < 0.05 scores regardless of whether the bedding was dry or wet. Scores increased as the slope increased (P < 0.01. Provision of bedding, other than feed, at slopes greater than zero, decreased slips, falls and vocalizations. The total time it took to load and unload pigs was

  4. From Modern Push-Button Hospital-beds to 20th Century Mechatronic Beds: A Review

    Science.gov (United States)

    Ghersi, I.; Mariño, M.; Miralles, M. T.

    2016-04-01

    The aim of this work is to present the different aspects of modern high complexity electric beds of the period 1940 until 2000 exclusively. The chronology of the product has been strictly divided into three big stages: electric and semi-electric beds (until the 90’s), mechatronic beds (90’s until 2000) and, mechatronic intelligent beds of the last 15 years. The latter are not considered in this work due to the extension for its analysis. The justification for classifying the product is presented under the concepts of medical, assistive and mobility devices. Relevant aspects of common immobility problems of the different types of patients for which the beds are mainly addressed are shown in detail. The basic functioning of the patient’s movement generator and the implementation of actuators, together with IT programs, specific accessories and connectivity means and network-communication shown in this work, were those that gave origin to current mechatronic beds. We present the historical evolution of high complexity electric beds by illustrating cases extracted from a meticulous time line, based on patents, inventions and publications in newspapers and magazines of the world. The criteria adopted to evaluate the innovation were: characteristics of controls; accessories (mattresses, lighting, siderails, etc.), aesthetic and morphologic properties and outstanding functionalities.

  5. Effect of bed particles to combustion of gases in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Raiko, R.; Wallen, V.; Etelaeaho, R.; Correia, S. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

    1997-10-01

    The objective of this project was to obtain experimental data on effects of sand particles to the combustion of gases. The effect of the surface area of the particles was tested using different sized particles. The fluidized bed reactor used in these experiments was a stainless-steel tube with an internal diameter of 42 mm surrounded by an electric heater. The test rig was built in the Laboratory of Energy and Process Engineering at Tampere University of Technology. In order to elucidate the possible changes of particle surface, microscopic and porosimetric studies were conducted with both fresh bed particles and used bed particles. These measurements indicate that carbon monoxide significantly reacts with oxygen in the particulate or emulsion phase of a fluidized bed, if the residence time is long enough. The reaction rate depends mainly on temperature, air coefficient, residence time and particle size of the solids. It seems that the combustion enhances if the average particle size increases. Whether this is caused by increased free path length or reduced specific surface area of the bed is yet unknown. The first might be more probable cause because the majority of reactions often took place in the freeboard right above the bed. It was clear that the bed hindered proper combustion in several cases. (orig.)

  6. Effects of bed-load movement on flow resistance over bed forms

    Indian Academy of Sciences (India)

    Mohammad Hossein Omid; Masoud Karbasi; Javad Farhoudi

    2010-12-01

    The effect of bed-load transport on flow resistance of alluvial channels with undulated bed was experimentally investigated. The experiments were carried out in a tilting flume 250 mm wide and 12·5 m long with glass-sides of rectangular cross-section and artificial dune shaped floor that was made from Plexi-glass. Steady flow of clear as against sediment-laden water with different flow depths and velocities were studied in the experiments with a fine sand ($d_{50} =$ 0·5 mm). The results indicate that the transport of fine particles ($d_{50} =$ 0·5 mm) can decrease the friction factor by 22% and 24% respectively for smooth and rough beds. Increasing the bed-load size ($d_{50} =$ 2·84 mm) can decrease the friction factor by 32% and 39% respectively for smooth and rough beds. The decrease in flow resistance is due to filling up of the troughs of dunes. This separation zone is responsible for increasing the flow resistance. On the upstream side of dunes condition is similar to plane bed. Presence of bed-load causes to increase the shear velocity and hence increasing flow resistance. But decreasing in flow resistance is more and it causes to decrease the total flow resistance. Grains saturated the troughs in the bed topography, effectively helping in smoothening of bed irregularities.

  7. A randomized trial to evaluate a launderable bed protection system for hospital beds.

    Science.gov (United States)

    Hooker, Edmond A; Allen, Steven; Gray, Larry; Kaufman, Cynthia

    2012-07-26

    Hospital beds are potential reservoirs of bacteria in hospitals. Preventing contamination of the bed and providing a cleaner surface should help prevent hospital-acquired infections (HAIs). Most hospital beds are cleaned between patients (terminal cleaning) using quaternary ammonia compounds (quats). The study had two objectives: identify levels of bacterial contamination on beds (including the mattress and bed deck) and evaluate a new launderable cover. Hospital beds on a bariatric surgery ward were randomized to either receive or not receive a launderable cover (Trinity Guardion, Batesville, IN). Bacterial counts on the surface of the mattress, the bed deck, and the launderable cover were then collected using Petrifilm™ Aerobic Count Plates (Petrifilm™, 3M™, St. Paul, MN, USA) (Petrifilm™) at three time periods (before patient use, after discharge, and after terminal cleaning). Standard hospital linen was used in all rooms. The launderable cover (n = 28) was significantly cleaner prior to patient use than were the cleaned mattresses (n = 38) (1.1 CFU/30 cm2 vs. 7.7 CFU/30 cm2; p = 0.0189). The mattresses without launderable covers became significantly contaminated during use (7.7 CFU/30 cm2 on admission vs. 79.1 CFU/30 cm2 after discharge; p bed deck was more contaminated (6.7 CFU/30 cm2 after discharge compared to 30.9 CFU/30 cm2 after terminal cleaning; p = 0.031). Terminal cleaning fails to eliminate bacteria from the surface of the hospital mattress. The launderable cover provides a cleaner surface than does terminal cleaning with quats, and the cover protects the bed from contamination during use.

  8. Modeling of structural effects in biomedical elements after titanium oxidation in fluidized bed

    Directory of Open Access Journals (Sweden)

    Mendzik K.

    2010-06-01

    Full Text Available Oxidation is one of the most employed methods to improve titanium and its alloys properties especially due to medical application. This process like most of the thermochemical treatment processes substantially influences on the characteristic of surface layers and the same on its mechanical and useful properties. Oxide coatings produced during titanium oxidation were examined due to their composition identification. Titanium was oxidized in fluidized bed in temperature range between 500÷700°C. Microstructures of titanium with a visible oxide coating on its surface after thermochemical treatment and changes of grain size in core of titanium samples are described. Moreover Xray phase analysis of obtained oxides coatings was made as well as microhardness measurements of titanium surface layers after oxidation process. Finally, the surfaces of titanium after oxidation in fluidized bed were measured by Auger electron spectroscopy. All research results are used to built numerical model of oxidation process in fluidized. Titanium oxidation process in fluidized bed is very complicated, because changes of parameters are non linear characteristics. This fact and lack of mathematical algorithms describing this process makes modeling properties of titanium elements by traditional numerical methods difficult or even impossible. In this case it is possible to try using artificial neural network. Using neural networks for modeling oxidizing in fluidized bed is caused by several nets' features: non linear character, ability to generalize the results of calculations for data out of training set, no need for mathematical algorithms describing influence changes input parameters on modeling materials properties.

  9. Discrete Fracture Networks Groundwater Modelling at Bedding Control Fractured Sedimentary Rock mass

    Science.gov (United States)

    Pin, Yeh; Yuan-Chieh, Wu

    2017-04-01

    Groundwater flow modelling in fractured rock mass is an important challenging work in predicting the transport of contamination. So far as we know about the numerical analysis method was consider for crystalline rock, which means discontinuous are treated as stochastic distribution in homogeneous rock mass. Based on the understanding of geology in Taiwan in past few decades, we know that the hydraulic conductivities of Quaternary and Tertiary system rock mass are strongly controlled by development of sedimentary structures (bedding plane). The main purpose of this study is to understand how Discrete Fracture Networks (DFN) affects numerical results in terms of hydraulic behavior using different DFN generation methods. Base on surface geology investigation and core drilling work (3 boreholes with a total length of 120m), small scale fracture properties with in Cho-lan formation (muddy sandstone) are defined, including gently dip of bedding and 2 sub-vertical joint sets. Two FracMan/MAFIC numerical modellings are conducted, using ECPM approach (Equivalent Continuum Porous Media); case A considered all fracture were Power law distribution with Poisson fracture center; case B considered all bedding plans penetrate into modelling region, and remove the bedding count to recalculate joint fracture parameters. Modelling results show that Case B gives stronger groundwater pathways than Case A and have impact on flow field. This preliminary modelling result implicates the groundwater flow modelling work in some fractured sedimentary rock mass, might be considerate to rock sedimentary structure development itself, discontinuous maybe not follow the same stochastic DFN parameter.

  10. NONUNIFORMITIES OF TWO-PHASE COOLANT DISTRIBUTION IN A HEAT GENERATING PARTICLES BED

    Directory of Open Access Journals (Sweden)

    V. V. Sorokin

    2014-01-01

    Full Text Available Sufficient atomic power generation safety increase may be done with microfuel adapting to reactor plants with water coolant. Microfuel particle is a millimeter size grain containing fission material core in a protecting coverage. The coverage protects fuel contact with coolant and provides isolation of fission products inside. Well thermophysical properties of microfuel bed in a direct contact with water coolant excludes fuel overheating when accidents. Microfuel use was suggested for a VVER, а direct flow reactor for superheat steam generation, a reactor with neutron spectra adjustment by the steam partial content varying in the coolant.Nonuniformities of two-phase coolant distribution in a heat generating particles bed are predicted by calculations in this text. The one is due to multiple-valuedness of pressure drop across the bed on the steam quality dependency. The nonuniformity decreases with flow rate and particle size growths absolute pressure diminishing while porosity effect is weak. The worse case is for pressure quality of order of one. Some pure steam filled pores appears parallel to steam water mixture filled pores, latter steam quality is less than the mean of the bed. Considering this regime for the direct flow reactor for superheat steam generation we predict some water drops at the exit flow. The two-phase coolant filtration with subcooled water feed is unstable to strong disturbance effects are found. Uniformity of two-phase coolant distribution is worse than for one-phase in the same radial type reactor.

  11. CFD-DEM simulation of a conceptual gas-cooled fluidized bed nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Lucilla C.; Su, Jian, E-mail: lucillalmeida@gmail.com, E-mail: sujian@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Aguirre, Joao, E-mail: aguirre@rocky-dem.com [Engineering Simulation and Scientific Software (ESSS), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Several conceptual designs of the fluidized-bed nuclear reactor have been proposed due to its many advantages over conventional nuclear reactors such as PWRs and BWRs. Amongst their characteristics, the enhanced heat transfer and mixing enables a more uniform temperature distribution, reducing the risk of hot-spot and excessive fuel temperature, in addition to resulting in a higher burnup of the fuel. Furthermore, the relationship between the bed height and reactor neutronics turns the coolant flow rate control into a power production mechanism. Moreover, the possibility of removing the fuel by gravity from the movable core in case of a loss-of-cooling accident increases its safety. High-accuracy modeling of particles and coolant flow in fluidized bed reactors is needed to evaluate reliably the thermal-hydraulic efficiency and safety margin. The two-way coupling between solid and fluid can account for high-fidelity solid-solid interaction and reasonable accuracy in fluid calculation and fluid-solid interaction. In the CFD-DEM model, the particles are modeled as a discrete phase, following the DEM approach, whereas the fluid flow is treated as a continuous phase, described by the averaged Navier-Stokes equations on a computational cell scale. In this work, the coupling methodology between Fluent and Rocky is described. The numerical approach was applied to the simulation of a bubbling fluidized bed and the results were compared to experimental data and showed good agreement. (author)

  12. IGCSE core mathematics

    CERN Document Server

    Wall, Terry

    2013-01-01

    Give your core level students the support and framework they require to get their best grades with this book dedicated to the core level content of the revised syllabus and written specifically to ensure a more appropriate pace. This title has been written for Core content of the revised Cambridge IGCSE Mathematics (0580) syllabus for first teaching from 2013. ? Gives students the practice they require to deepen their understanding through plenty of practice questions. ? Consolidates learning with unique digital resources on the CD, included free with every book. We are working with Cambridge

  13. Core shroud corner joints

    Science.gov (United States)

    Gilmore, Charles B.; Forsyth, David R.

    2013-09-10

    A core shroud is provided, which includes a number of planar members, a number of unitary corners, and a number of subassemblies each comprising a combination of the planar members and the unitary corners. Each unitary corner comprises a unitary extrusion including a first planar portion and a second planar portion disposed perpendicularly with respect to the first planar portion. At least one of the subassemblies comprises a plurality of the unitary corners disposed side-by-side in an alternating opposing relationship. A plurality of the subassemblies can be combined to form a quarter perimeter segment of the core shroud. Four quarter perimeter segments join together to form the core shroud.

  14. Mineral resources of the Devil's Garden Lava Bed, Squaw Ridge Lava Bed, and Four Craters Lava Bed Wilderness Study Areas, Lake County, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    Keith, W.J.; King, H.D.; Gettings, M.E. (Geological Survey, Reston, VA (USA)); Johnson, F.L. (US Bureau of Mines (US))

    1988-01-01

    The Devel's Garden lava Bed, Squaw Ridge Lava Bed, and Four Craters Lava Bed Wilderness Study Areas include approximately 70,940 acres and are underlain entirely by Pleistocene or Holocene lava flows and associated sediments. There is no evidence of hydrothermal alteration in the study areas. No resources were identified in the study areas, but there is low potential for perlite resources in the southern part of the Devil's Garden Lava Bed and the northern half of the Squaw Ridge Lava Bed areas. All three study areas have low potential for geothermal resources and for oil and gas resources.

  15. Three-dimensional flow structure and patterns of bed shear stress in an evolving compound meander bend

    Science.gov (United States)

    Engel, Frank; Rhoads, Bruce L.

    2016-01-01

    Compound meander bends with multiple lobes of maximum curvature are common in actively evolving lowland rivers. Interaction among spatial patterns of mean flow, turbulence, bed morphology, bank failures and channel migration in compound bends is poorly understood. In this paper, acoustic Doppler current profiler (ADCP) measurements of the three-dimensional (3D) flow velocities in a compound bend are examined to evaluate the influence of channel curvature and hydrologic variability on the structure of flow within the bend. Flow structure at various flow stages is related to changes in bed morphology over the study timeframe. Increases in local curvature within the upstream lobe of the bend reduce outer bank velocities at morphologically significant flows, creating a region that protects the bank from high momentum flow and high bed shear stresses. The dimensionless radius of curvature in the upstream lobe is one-third less than that of the downstream lobe, with average bank erosion rates less than half of the erosion rates for the downstream lobe. Higher bank erosion rates within the downstream lobe correspond to the shift in a core of high velocity and bed shear stresses toward the outer bank as flow moves through the two lobes. These erosion patterns provide a mechanism for continued migration of the downstream lobe in the near future. Bed material size distributions within the bend correspond to spatial patterns of bed shear stress magnitudes, indicating that bed material sorting within the bend is governed by bed shear stress. Results suggest that patterns of flow, sediment entrainment, and planform evolution in compound meander bends are more complex than in simple meander bends. Moreover, interactions among local influences on the flow, such as woody debris, local topographic steering, and locally high curvature, tend to cause compound bends to evolve toward increasing planform complexity over time rather than stable configurations.

  16. A COMPARISON OF PEBBLE MIXING AND DEPLETION ALGORITHMS USED IN PEBBLE-BED REACTOR EQUILIBRIUM CYCLE SIMULATION

    Energy Technology Data Exchange (ETDEWEB)

    Hans D. Gougar; Frederik Reitsma; Wessel Joubert

    2009-05-01

    Recirculating pebble-bed reactors are distinguished from all other reactor types by the downward movement through and reinsertion of fuel into the core during operation. Core simulators must account for this movement and mixing in order to capture the physics of the equilibrium cycle core. VSOP and PEBBED are two codes used to perform such simulations, but they do so using different methods. In this study, a simplified pebble-bed core with a specified flux profile and cross sections is used as the model for conducting analyses of two types of burnup schemes. The differences between the codes are described and related to the differences observed in the nuclide densities in pebbles discharged from the core. Differences in the methods for computing fission product buildup and average number densities lead to significant differences in the computed core power and eigenvalue. These test models provide a key component of an overall equilibrium cycle benchmark involving neutron transport, cross section generation, and fuel circulation.

  17. Monitoring nocturnal heart rate with bed sensor.

    Science.gov (United States)

    Migliorini, M; Kortelainen, J M; Pärkkä, J; Tenhunen, M; Himanen, S L; Bianchi, A M

    2014-01-01

    This article is part of the Focus Theme of Methods of Information in Medicine on "Biosignal Interpretation: Advanced Methods for Studying Cardiovascular and Respiratory Systems". The aim of this study is to assess the reliability of the estimated Nocturnal Heart Rate (HR), recorded through a bed sensor, compared with the one obtained from standard electrocardiography (ECG). Twenty-eight sleep deprived patients were recorded for one night each through matrix of piezoelectric sensors, integrated into the mattress, through polysomnography (PSG) simultaneously. The two recording methods have been compared in terms of signal quality and differences in heart beat detection. On average, coverage of 92.7% of the total sleep time was obtained for the bed sensor, testifying the good quality of the recordings. The average beat-to-beat error of the inter-beat intervals was 1.06%. These results suggest a good overall signal quality, however, considering fast heart rates (HR > 100 bpm), performances were worse: in fact, the sensitivity in the heart beat detection was 28.4% while the false positive rate was 3.8% which means that a large amount of fast beats were not detected. The accuracy of the measurements made using the bed sensor has less than 10% of failure rate especially in periods with HR lower than 70 bpm. For fast heart beats the uncertainty increases. This can be explained by the change in morphology of the bed sensor signal in correspondence of a higher HR.

  18. Control of fluidized bed tea drying

    NARCIS (Netherlands)

    Temple, S.J.

    2000-01-01

    Tea is a product made from the leaf of the tea bush by several processes, including drying. The drying stage is the most energy intensive, and has tight performance criteria. This project investigated the options for the control of a fluidized bed tea dryer. The work included establishing some of th

  19. Agglomeration in fluidized beds: detection and counteraction

    NARCIS (Netherlands)

    Bartels. M.

    2008-01-01

    Fluidized beds comprise a quantity of solid particles that is suspended by an upward flowing gas. They are used for a variety of processes in the chemical industry, such as catalytic reactions, drying, coating and energy conversion. A major problem in industrial practice is the occurrence of unwante

  20. Multiscale modeling of gas-fluidized beds

    NARCIS (Netherlands)

    van der Hoef, Martin Anton; van Sint Annaland, M.; Ye, M.; Andrews, A.T.; Sundaresan, S.; Kuipers, J.A.M.

    2006-01-01

    Numerical models of gas-fluidized beds have become an important tool in the design and scale up of gas-solid chemical reactors. However, a single numerical model which includes the solid-solid and solid-fluid interaction in full detail is not feasible for industrial-scale equipment, and for this

  1. Endogenous pancreatic polypeptide in different vascular beds

    DEFF Research Database (Denmark)

    Henriksen, J H; Schwartz, Tania; Bülow, J B

    1986-01-01

    The plasma concentration of pancreatic polypeptide (PP-like immunoreactivity) was measured in different vascular beds in order to determine regional kinetics of endogenous PP in fasting, supine subjects with normal or moderately decreased kidney function. Patients with kidney disease (n = 10) had...

  2. Wound bed preparation from a clinical perspective

    Directory of Open Access Journals (Sweden)

    A S Halim

    2012-01-01

    Full Text Available Wound bed preparation has been performed for over two decades, and the concept is well accepted. The ′TIME′ acronym, consisting of tissue debridement, i nfection or inflammation, moisture balance and edge effect, has assisted clinicians systematically in wound assessment and management. While the focus has usually been concentrated around the wound, the evolving concept of wound bed preparation promotes the treatment of the patient as a whole. This article discusses wound bed preparation and its clinical management components along with the principles of advanced wound care management at the present time. Management of tissue necrosis can be tailored according to the wound and local expertise. It ranges from simple to modern techniques like wet to dry dressing, enzymatic, biological and surgical debridement. Restoration of the bacterial balance is also an important element in managing chronic wounds that are critically colonized. Achieving a balance moist wound will hasten healing and correct biochemical imbalance by removing the excessive enzymes and growth factors. This can be achieved will multitude of dressing materials. The negative pressure wound therapy being one of the great breakthroughs. The progress and understanding on scientific basis of the wound bed preparation over the last two decades are discussed further in this article in the clinical perspectives.

  3. Cognitive nonlinear radar test-bed

    Science.gov (United States)

    Hedden, Abigail S.; Wikner, David A.; Martone, Anthony; McNamara, David

    2013-05-01

    Providing situational awareness to the warfighter requires radar, communications, and other electronic systems that operate in increasingly cluttered and dynamic electromagnetic environments. There is a growing need for cognitive RF systems that are capable of monitoring, adapting to, and learning from their environments in order to maintain their effectiveness and functionality. Additionally, radar systems are needed that are capable of adapting to an increased number of targets of interest. Cognitive nonlinear radar may offer critical solutions to these growing problems. This work focuses on ongoing efforts at the U.S. Army Research Laboratory (ARL) to develop a cognitive nonlinear radar test-bed. ARL is working toward developing a test-bed that uses spectrum sensing to monitor the RF environment and dynamically change the transmit waveforms to achieve detection of nonlinear targets with high confidence. This work presents the architecture of the test-bed system along with a discussion of its current capabilities and limitations. A brief outlook is presented for the project along with a discussion of a future cognitive nonlinear radar test-bed.

  4. Multiscale modeling of gas-fluidized beds

    NARCIS (Netherlands)

    Hoef, van der M.A.; Sint Annaland, van M.; Andrews, A.T.; Sundaresan, S.; Kuipers, J.A.M.

    2006-01-01

    Numerical models of gas-fluidized beds have become an important tool in the design and scale up of gas-solid chemical reactors. However, a single numerical model which includes the solid-solid and solid-fluid interaction in full detail is not feasible for industrial-scale equipment, and for this rea

  5. Exercise Training During Bed Rest Attenuates Deconditioning

    Science.gov (United States)

    Greenleaf, J. E.; Hargens, Alan R. (Technical Monitor)

    1995-01-01

    A 30-day 6 deg. head-down bed rest study was conducted to evaluate high-intensity, short-duration, alternating isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent isokinetic exercise (IKE) training regiments designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (acclimation) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volume, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (a) attenuated the decrease in peak VO2 by 50%, (b) attenuated loss of red cell volume by 40%, but had no effect on loss of plasma volume, (c) induced positive body water balance, (d) had no adverse effect on quality of sleep or concentration, and (e) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regiments, and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

  6. Bed roughness experiments in supply limited conditions

    NARCIS (Netherlands)

    Spekkers, Matthieu; Tuijnder, Arjan; Ribberink, Jan S.; Hulscher, Suzanne J.M.H.; Parsons, D.R.; Garlan, T.; Best, J.L.

    2008-01-01

    Reliable roughness models are of great importance, for example, when predicting water levels in rivers. The currently available roughness models are based on fully mobile bed conditions. However, in rivers where widely graded sediments are present more or less permanent armour layers can develop

  7. A curved flume bed-load experiment

    NARCIS (Netherlands)

    Talmon, A.M.; Marsman, E.R.A.

    1988-01-01

    In this report the results of a bed-load experiment in a curved flume are presented. The experiments have been carried out in the Laboratory of Fluid Mechanics (L.F.M.) at the Delft University of Technology. The main object of the experiments is to develop and to test data-acquisition procedures for

  8. Modelling of Devolatilization in Fluidized Bed Combustion

    DEFF Research Database (Denmark)

    Stenseng, Mette; Lin, Weigang; Johnsson, Jan Erik

    1997-01-01

    A mathematical model is developed to describe the devolatilization process in a circulating fluidized bed combustor. The model is a combination of two submodels: single particle devolatilization and fluid dynamics. The single particle model includes the influence of both chemical kinetics and hea...

  9. Cardiac atrophy in women following bed rest.

    Science.gov (United States)

    Dorfman, Todd A; Levine, Benjamin D; Tillery, Tommy; Peshock, Ronald M; Hastings, Jeff L; Schneider, Suzanne M; Macias, Brandon R; Biolo, Gianni; Hargens, Alan R

    2007-07-01

    Both chronic microgravity exposure and long-duration bed rest induce cardiac atrophy, which leads to reduced standing stroke volume and orthostatic intolerance. However, despite the fact that women appear to be more susceptible to postspaceflight presyncope and orthostatic hypotension than male astronauts, most previous high-resolution studies of cardiac morphology following microgravity have been performed only in men. Because female athletes have less physiological hypertrophy than male athletes, we reasoned that they also might have altered physiological cardiac atrophy after bed rest. Magnetic resonance imaging was performed in 24 healthy young women (32.1 +/- 4 yr) to measure left ventricular (LV) and right ventricular (RV) mass, volumes, and morphology accurately before and after 60 days of 6 degrees head-down tilt (HDT) bed rest. Subjects were matched and then randomly assigned to sedentary bed rest (controls, n = 8) or two treatment groups consisting of 1) exercise training using supine treadmill running within lower body negative pressure plus resistive training (n = 8), or 2) protein (0.45 g x kg(-1) x day(-1) increase) plus branched-chain amino acid (BCAA) (7.2 g/day) supplementation (n = 8). After sedentary bed rest without nutritional supplementation, there were significant reductions in LV (96 +/- 26 to 77 +/- 25 ml; P = 0.03) and RV volumes (104 +/- 33 to 86 +/- 25 ml; P = 0.02), LV (2.2 +/- 0.2 to 2.0 +/- 0.2 g/kg; P = 0.003) and RV masses (0.8 +/- 0.1 to 0.6 +/- 0.1 g/kg; P men (8.0%; Perhonen MA, Franco F, Lane LD, Buckey JC, Blomqvist Zerwekh JE, Peshock RM, Weatherall PT, Levine BD. J Appl Physiol 91: 645-653, 2001). In contrast, there were no significant reductions in LV or RV volumes in the exercise-trained group, and the length of the major axis was preserved. Moreover, there were significant increases in LV (1.9 +/- 0.4 to 2.3 +/- 0.3 g/kg; P women similar to men following sedentary 60 days HDT bed rest. However, exercise training and, to a

  10. Biospecimen Core Resource - TCGA

    Science.gov (United States)

    The Cancer Genome Atlas (TCGA) Biospecimen Core Resource centralized laboratory reviews and processes blood and tissue samples and their associated data using optimized standard operating procedures for the entire TCGA Research Network.

  11. NICHD Zebrafish Core

    Data.gov (United States)

    Federal Laboratory Consortium — The core[HTML_REMOVED]s goal is to help researchers of any expertise perform zebrafish experiments aimed at illuminating basic biology and human disease mechanisms,...

  12. iPSC Core

    Data.gov (United States)

    Federal Laboratory Consortium — The induced Pluripotent Stem Cells (iPSC) Core was created in 2011 to accelerate stem cell research in the NHLBI by providing investigators consultation, technical...

  13. Reference: -300CORE [PLACE

    Lifescience Database Archive (English)

    Full Text Available -300CORE Forde BG, Heyworth A, Pywell J, Kreis M Nucleotide sequence of a B1 hordein gene and the identifica...tion of possible upstream regulatory elements in endosperm storage protein genes fr

  14. INTEGRAL core programme

    Science.gov (United States)

    Gehrels, N.; Schoenfelder, V.; Ubertini, P.; Winkler, C.

    1997-01-01

    The International Gamma Ray Astrophysics Laboratory (INTEGRAL) mission is described with emphasis on the INTEGRAL core program. The progress made in the planning activities for the core program is reported on. The INTEGRAL mission has a nominal lifetime of two years with a five year extension option. The observing time will be divided between the core program (between 30 and 35 percent during the first two years) and general observations. The core program consists of three main elements: the deep survey of the Galactic plane in the central radian of the Galaxy; frequent scans of the Galactic plane in the search for transient sources, and pointed observations of several selected sources. The allocation of the observation time is detailed and the sensitivities of the observations are outlined.

  15. Focusing on Core Business

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    China is regulating state-owned enterprises that are investing outside of their core business realms, concerned that poor investment decisions could lead to loss of state-owned assets, but some doubt the effect of the new regulation

  16. Organizing Core Tasks

    DEFF Research Database (Denmark)

    Boll, Karen

    Civil servants conduct the work which makes welfare states functions on an everyday bases: Police men police, school teachers teach, and tax inspectors inspect. Focus in this paper is on the core tasks of tax inspectors. The paper argues that their core task of securing the collection of revenue...... has remained much the same within the last 10 years. However, how the core task has been organized has changed considerable under the influence of various “organizing devices”. The paper focusses on how organizing devices such as risk assessment, output-focus, effect orientation, and treatment...... projects influence the organization of core tasks within the tax administration. The paper shows that the organizational transformations based on the use of these devices have had consequences both for the overall collection of revenue and for the employees’ feeling of “making a difference”. All in all...

  17. Contribution to modeling of the reflooding of a severely damaged reactor core using PRELUDE experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Bachrata, A.; Fichot, F.; Repetto, G. [Institut de Radioprotection et de Surete Nucleaire IRSN, Cadarache (France); Quintard, M. [Universite de Toulouse, INPT, UPS, IMFT Institut de Mecanique des Fluides de Toulouse, Allee Camille Soula, F-31400 Toulouse (France); CNRS, IMFT, F-31400 Toulouse (France); Fleurot, J. [Institut de Radioprotection et de Surete Nucleaire IRSN, Cadarache (France)

    2012-07-01

    In case of accident at a nuclear power plant, water sources may not be available for a long period of time and the core heats up due to the residual power. The reflooding (injection of water into core) may be applied if the availability of safety injection is recovered during accident. If the injection becomes available only in the late phase of accident, water will enter a core configuration that will differ significantly from original rod-bundle geometry. Any attempt to inject water after significant core degradation can lead to further fragmentation of core material. The fragmentation of fuel rods may result in the formation of a 'debris bed'. The typical particle size in a debris bed might reach few millimeters (characteristic length-scale: 1 to 5 mm), i.e., a high permeability porous medium. The French 'Institut de Radioprotection et de Surete Nucleaire' is developing experimental programs (PEARL and PRELUDE) and simulation tools (ICARE-CATHARE and ASTEC) to study and optimize the severe accident management strategy and to assess the probabilities to stop the progress of in-vessel core degradation. It is shown that the quench front exhibits either a ID behaviour or a 2D one, depending on injection rate or bed characteristics. The PRELUDE experiment covers a rather large range of variation of parameters, for which the developed model appears to be quite predictive. (authors)

  18. Acute psychiatric beds: distribution and staffing in NSW and ACT.

    Science.gov (United States)

    Rosenman, S

    1995-06-01

    This study examined the availability and staffing of acute psychiatry beds in NSW and ACT. "Gazetted" acute psychiatry hospitals (which take compulsory admissions under mental health law) were polled directly for bed numbers, occupancy and staffing for the year 1990-1991. The NSW Department of Health provided beds numbers for non-gazetted and private hospitals. Four analyses sequentially reallocated beds according to the origin of patients to estimate acute bed availability and use by regional populations. Socio-demographic determinants of acute admission rates were measured. Acute "gazetted" beds averaged 13.2 per 100,000 population but ranged from 6.9 to 49.1 per 100,000 when cross-regional flows were considered. "Non-gazetted" beds raised the provision to 15.5 per 100,000 and private beds raised provision further to 24.5 per 100,000. Inner metropolitan provision was higher than rural or provincial provision. The only determinant of the admission rate to gazetted beds was the number of available beds. Bed availability did not affect either bed occupancy or referral of patients to remote hospitals. Nursing staffing of gazetted units was reasonably uniform, although smaller units had significantly more nurses per bed. Medical staffing was highly variable and appears determined by staff availability. The average provision of acute psychiatric beds approximates lowest levels seen in international models for psychiatric services. Average occupancy rates suggest that there is not an overall shortfall of acute psychiatric beds, but uneven bed distribution creates barriers to access. Referral of patients to remote hospitals is not related to actual bed provision in the regions, but appears to reflect attitudes to ensuring local care. Recommendations about current de facto standards are made. Current average nursing and medical staffing standards are reported.

  19. Atmospheric fluidized bed combustion advanced concept system

    Energy Technology Data Exchange (ETDEWEB)

    1992-05-01

    DONLEE Technologies Inc. is developing with support of the US Department of Energy an advanced circulating fluidized bed technology known as the Vortex{trademark} Fluidized Bed Combustor (VFBC). The unique feature of the VFBC is the injection of a significant portion of the combustion air into the cyclone. Since as much as one-half of the total combustion air is injected into the cyclone, the cross-sectional area of the circulating fluidized bed is considerably smaller than typical circulating fluidized beds. The technology is being developed for two applications: Industrial-scale boilers ranging from 20,000 to 100,000 pounds per hour steam generating capacity; and two-stage combustion in which a substoichiometric Vortex Fluidized Bed Combustor (2VFBC) or precombustor is used to generate a combustible gas for use primarily in boiler retrofit applications. This Level II analysis of these two applications indicates that both have merit. An industrial-scale VFBC boiler (60,000 lb/hr of steam) is projected to be economically attractive with coal prices as high as $40 per ton and gas prices between $4 and $5 per thousand cubic feet. The payback time is between 3 and 4 years. The 2VFBC system was evaluated at three capacities of application: 20,000; 60,000 and 100,000 lb/hr of steam. The payback times for these three capacities are 4.5, 2.1 and 1.55 years, respectively. The 2VFBC has potential applications for retrofit of existing pulverized coal-fired boilers or as a new large (utility) boiler. Pressurized operation of the 2VFBC has considerable potential for combined cycle power generation applications. Experimental development of both applications is presented here to demonstrate the potential of these two technologies.

  20. Multi-bed patient room architectural evaluation

    Directory of Open Access Journals (Sweden)

    Evangelia Sklavou

    2016-12-01

    Full Text Available Introduction: Leveraging the physical environment’s merits is crucial in healthcare settings towards fostering sustainable healing conditions. In the future, the need to retrofit hospitals already appears more probable than to build new facilities. In Greece, holistic healthcare architecture has significant potential and room to develop. Aim: The architectural research of multi-bed patient room environment. Method: A sample of multi-bed patient rooms of a Greek hospital was studied per architectural documentation and user evaluation survey. Beyond recording the existing situation and user experience, user group differences and the influence of window proximity were studied. The survey sample was based on convenience and comprised 160 patients and 136 visitors. Statistical analysis was performed in SPSS 20, using chi-square exact tests of independence. The chosen level of significance was p < 0.05. Results: Architectural documentation showed that the building morphology had a positive impact in patient rooms, with regard to sunlight penetration and view. Further solar daylight control was deemed necessary, to facilitate overall environmental comfort conditions. High spatial density and considerable disadvantages of the middle patient bed, compared to the one bedside the window and the one further in the back of the room, were also ascertained. User groups did not evaluate their surroundings significantly different, with the exception of ease of access to the view. Window proximity influenced both patients and visitors in evaluating ease of access to the view and visual discomfort. Patients were further affected on window size evaluation and visitors on view related aspects. Conclusions: Synergy between building form and function contributes in creating holistic sustainable healing environments. User evaluation can deviate from objective documentation. Patients and visitors experienced the patient room in a similar manner. The middle bed was