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Sample records for brookhaven high flux

  1. Rebuilding the Brookhaven high flux beam reactor: A feasibility study

    International Nuclear Information System (INIS)

    After nearly thirty years of operation, Brookhaven's High Flux Beam Reactor (HFBR) is still one of the world's premier steady-state neutron sources. A major center for condensed matter studies, it currently supports fifteen separate beamlines conducting research in fields as diverse as crystallography, solid-state, nuclear and surface physics, polymer physics and structural biology and will very likely be able to do so for perhaps another decade. But beyond that point the HFBR will be running on borrowed time. Unless appropriate remedial action is taken, progressive radiation-induced embrittlement problems will eventually shut it down. Recognizing the HFBR's value as a national scientific resource, members of the Laboratory's scientific and reactor operations staffs began earlier this year to consider what could be done both to extend its useful life and to assure that it continues to provide state-of-the-art research facilities for the scientific community. This report summarizes the findings of that study. It addresses two basic issues: (i) identification and replacement of lifetime-limiting components and (ii) modifications and additions that could expand and enhance the reactor's research capabilities

  2. Job and Task Analysis project at Brookhaven National Laboratory's high flux beam reactor

    International Nuclear Information System (INIS)

    The presenter discussed the Job and Task Analysis (JTA) project conducted at Brookhaven National Laboratory's High Flux Beam Reactor (HFBR). The project's goal was to provide JTA guidelines for use by DOE contractors, then, using the guidelines conduct a JTA for the reactor operator and supervisor positions at the HFBR. Details of the job analysis and job description preparation as well as details of the task selection and task analysis were given. Post JTA improvements to the HFBR training programs were covered. The presentation concluded with a listing of the costs and impacts of the project

  3. Structural biology facilities at Brookhaven National Laboratory`s high flux beam reactor

    Energy Technology Data Exchange (ETDEWEB)

    Korszun, Z.R.; Saxena, A.M.; Schneider, D.K. [Brookhaven National Laboratory, Upton, NY (United States)

    1994-12-31

    The techniques for determining the structure of biological molecules and larger biological assemblies depend on the extent of order in the particular system. At the High Flux Beam Reactor at the Brookhaven National Laboratory, the Biology Department operates three beam lines dedicated to biological structure studies. These beam lines span the resolution range from approximately 700{Angstrom} to approximately 1.5{Angstrom} and are designed to perform structural studies on a wide range of biological systems. Beam line H3A is dedicated to single crystal diffraction studies of macromolecules, while beam line H3B is designed to study diffraction from partially ordered systems such as biological membranes. Beam line H9B is located on the cold source and is designed for small angle scattering experiments on oligomeric biological systems.

  4. Technical Safety Requirement Violation at the High Flux Beam Reactor Decommissioning Project, Brookhaven, United States of America

    International Nuclear Information System (INIS)

    At Brookhaven National Laboratory (BNL) on 6 July 2009, a technical safety requirement (TSR) violation was declared at the high flux beam reactor (HFBR) project, which was a limited scope decontamination and decommissioning project associated with the permanently shutdown reactor. The violation extended from performing decommissioning activities within the facility under the incorrect mode. The draining of the spent fuel pool was performed in the warm standby mode when it should have been in the operation mode. The TSR was developed contrary to the United States Department of Energy (DOE) TSR guidance, which recommends that facility operations should only be carried out in the operation mode. The facility TSR allowed operations to be carried out in both modes. The HFBR operation mode focused on the removal of a small number of highly irradiated components with associated limited conditions of operation (LCO), while the warm standby mode focused on all other tasks in the facility and did not require entry into the LCO

  5. BROOKHAVEN: High energy gold

    International Nuclear Information System (INIS)

    On April 24, Brookhaven's Alternating Gradient Synchrotron (AGS) started to deliver gold ions at 11.4 GeV per nucleon (2,000 GeV per ion) to experimenters who were delighted not only to receive the world's highest energy gold beam but also to receive it on schedule

  6. Type A Verification Report For The High Flux Beam Reactor Stack And Grounds, Brookhaven National Laboratory, Upton, New York DCN: 5098-SR-08-0

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) Order 458.1 requires independent verification (IV) of DOE cleanup projects (DOE 2011). The Oak Ridge Institute for Science and Education (ORISE) has been designated as the responsible organization for IV of the High Flux Beam Reactor (HFBR) Stack and Grounds area at Brookhaven National Laboratory (BNL) in Upton, New York. The IV evaluation may consist of an in-process inspection with document and data reviews (Type A Verification) or a confirmatory survey of the site (Type B Verification). DOE and ORISE determined that a Type A verification of the documents and data for the HFBR Stack and Grounds: Survey Units (SU) 6, 7, and 8 was appropriate based on the initial survey unit classification, the walkover surveys, and the final analytical results provided by the Brookhaven Science Associates (BSA).

  7. Design of a high-flux epithermal neutron beam using 235U fission plates at the Brookhaven Medical Research Reactor.

    Science.gov (United States)

    Liu, H B; Brugger, R M; Rorer, D C; Tichler, P R; Hu, J P

    1994-10-01

    Beams of epithermal neutrons are being used in the development of boron neutron capture therapy for cancer. This report describes a design study in which 235U fission plates and moderators are used to produce an epithermal neutron beam with higher intensity and better quality than the beam currently in use at the Brookhaven Medical Research Reactor (BMRR). Monte Carlo calculations are used to predict the neutron and gamma fluxes and absorbed doses produced by the proposed design. Neutron flux measurements at the present epithermal treatment facility (ETF) were made to verify and compare with the computed results where feasible. The calculations indicate that an epithermal neutron beam produced by a fission-plate converter could have an epithermal neutron intensity of 1.2 x 10(10) n/cm2.s and a fast neutron dose per epithermal neutron of 2.8 x 10(-11) cGy.cm2/nepi plus being forward directed. This beam would be built into the beam shutter of the ETF at the BMRR. The feasibility of remodeling the facility is discussed. PMID:7869995

  8. INDEPENDENT VERIFICATION SURVEY OF THE HIGH FLUX BEAM REACTOR DECOMMISSIONING PROJECT OUTSIDE AREAS BROOKHAVEN NATIONAL LABORATORY UPTON, NEW YORK

    International Nuclear Information System (INIS)

    The objective of the verification survey was to obtain evidence by means of measurements and sampling to confirm that the final radiological conditions meet the established cleanup goals. This objective was achieved via multiple verification components including document reviews, instrument scans, and sample analysis to determine the accuracy and adequacy of FSS documentation. During the period between August 18 to 25 and September 24 to 29, 2010, ORISE conducted measurements and sampling of the HFBR 'Outside Areas' at the BNL site. ORISE performed gamma walkover scans in all eight SUs with SUs 2, 4, 6, 7, and 8 receiving high density scans of accessible areas. The remainder of SUs received low density scans. While scanning, ORISE team members observed a significant spike in count rate activity in SU 8. Just as quickly as the count rate increased the count rate decreased. A previous pass in the area did not identify any activity associated with soil contamination. The team determined that both detector instrument electronics functioned normally, and that the increased activity was due to a site activity. All individual sample concentrations and corresponding mean concentrations evaluated were determined to be below the established cleanup goal. A review of the data collected by ORISE has not identified any areas of contamination exceeding cleanup goals.

  9. PROJECT-SPECIFIC TYPE A VERIFICATION FOR THE HIGH FLUX BEAM REACTOR UNDERGROUND UTILITIES REMOVAL PHASE 3 TRENCH 5, BROOKHAVEN NATIONAL LABORATORY UPTON, NEW YORK

    International Nuclear Information System (INIS)

    The Oak Ridge Institute for Science and Education (ORISE) has reviewed the project documentation and data for the High Flux Beam Reactor (HFBR) Underground Utilities removal Phase 3; Trench 5 at Brookhaven National Laboratory (BNL) in Upton, New York. The Brookhaven Survey Group (BSG) has completed removal and performed Final Status Survey (FSS) of the concrete duct from Trench 5 from Building 801 to the Stack. Sample results have been submitted as required to demonstrate that the cleanup goal of (le)15 mrem/yr above background to a resident in 50 years has been met. Four rounds of sampling, from pre-excavation to FSS, were performed as specified in the Field Sampling Plan (FSP) (BNL 2010a). It is the policy of the U.S. Department of Energy (DOE) to perform independent verifications of decontamination and decommissioning activities conducted at DOE facilities. ORISE has been designated as the organization responsible for this task for the HFBR Underground Utilities. ORISE, together with DOE, determined that a Type A verification of Trench 5 was appropriate based on recent verification results from Trenches 2, 3, and 4, and the minimal potential for residual radioactivity in the area. The removal of underground utilities is being performed in three stages to decommission the HFBR facility and support structures. Phase 3 of this project included the removal of at least 200 feet of 36-inch to 42-inch pipe from the west side to the south side of Building 801, and the 14-inch diameter Acid Waste Line that spanned from 801 to the Stack within Trench 5. Based on the pre-excavation sample results of the soil overburden the potential for contamination of the soil surrounding the pipe is minimal (BNL 2010a). ORISE reviewed the BNL FSP and identified comments for consideration (ORISE 2010). BNL prepared a revised FSP that resolved each ORISE comment adequately (BNL 2010a). ORISE referred to the revised HFBR Underground Utilities FSP FSS data to conduct the Type A verification

  10. BROOKHAVEN

    International Nuclear Information System (INIS)

    Neutrino physics has been an integral part of the Brookhaven research programme for much of the Laboratory's 46-year history. Milestones have been the determination of the helicity of neutrinos (1958), the establishment of the existence of two kinds of neutrinos (1962) for which Leon Lederman, Mel Schwartz and Jack Steinberger were awarded the 1988 Nobel Physics Prize, the discovery of charmed baryons in the 7' Bubble Chamber in 1975, and the ongoing measurements by Ray Davis and collaborators of solar neutrinos, first reported in 1968. There have also been significant contributions to the understanding of neutral currents in exclusive hadron and electron channels. In addition some of the earliest, and to date best, accelerator limits on electron muon neutrino oscillations are from Brookhaven experiments. The Laboratory is also the 'B' in the IMB underground experiment, built to search for proton decay and which caught neutrinos from the SN 1987a supernova. At present Brookhaven is heavily involved in the Gallex project in the Gran Sasso and recently a new collaboration has received scientific approval for a long baseline experiment to search for muon neutrino oscillations via muon neutrino disappearance

  11. PROJECT-SPECIFIC TYPE A VERIFICATION FOR THE HIGH FLUX BEAM REACTOR UNDERGROUND UTILITIES REMOVAL PHASE 3 TRENCH 1, BROOKHAVEN NATIONAL LABORATORY UPTON, NEW YORK

    International Nuclear Information System (INIS)

    The Oak Ridge Institute for Science and Education (ORISE) has reviewed the project documentation and data for the High Flux Beam Reactor (HFBR) Underground Utilities removal Phase 3; Trench 1 at Brookhaven National Laboratory (BNL) in Upton, New York. The Brookhaven Survey Group (BSG) has completed removal and performed Final Status Survey (FSS) of the 42-inch duct and 14-inch line in Trench 1 from Building 801 to the Stack. Sample results have been submitted as required to demonstrate that the cleanup goal of (le)15 mrem/yr above background to a resident in 50 years has been met. Four rounds of sampling, from pre-excavation to FSS, were performed as specified in the Field Sampling Plan (FSP) (BNL 2010a). It is the policy of the U.S. Department of Energy (DOE) to perform independent verifications of decontamination and decommissioning activities conducted at DOE facilities. ORISE has been designated as the organization responsible for this task for the HFBR Underground Utilities. ORISE, together with DOE, determined that a Type A verification of Trench 1 was appropriate based on recent verification results from Trenches 2, 3, 4, and 5, and the minimal potential for residual radioactivity in the area. The removal of underground utilities has been performed in three stages to decommission the HFBR facility and support structures. Phase 3 of this project included the removal of at least 200 feet of 36-inch to 42-inch duct from the west side to the south side of Building 801, and the 14-inch diameter Acid Waste Line that spanned from 801 to the Stack within Trench 1. Based on the pre-excavation sample results of the soil overburden, the potential for contamination of the soil surrounding the pipe is minimal (BNL 2010a). ORISE reviewed the gamma spectroscopy results for 14 FSS soil samples, four core samples, and one duplicate sample collected from Trench 1. Sample results for the radionuclides of concern were below the established cleanup goals. However, in sample PH-3

  12. LETTER REPORT - INDEPENDENT VERIFICATION OF THE HIGH FLUX BEAM REACTOR DECOMMISSIONING PROJECT FAN HOUSE, BUILDING 704 BROOKHAVEN NATIONAL LABORATORY UPTON, NEW YORK

    International Nuclear Information System (INIS)

    Oak Ridge Institute for Science and Education (ORISE) personnel visited the Brookhaven National Laboratory (BNL) on August 17 through August 23, 2010 to perform visual inspections and conduct independent measurement and sampling of the 'Outside Areas' at the High Flux Beam Reactor (HFBR) decommissioning project. During this visit, ORISE was also able to evaluate Fan House, Building 704 survey units (SUs) 4 and 5, which are part of the Underground Utilities portion of the HFBR decommissioning project. ORISE performed limited alpha plus beta scans of the remaining Fan House foundation lower walls and remaining pedestals while collecting static measurements. Scans were performed using gas proportional detectors coupled to ratemeter-scalers with audible output and encompassed an area of approximately 1 square meter around the static measurement location. Alpha plus beta scans ranged from 120 to 460 cpm. Twenty smears for gross alpha and beta activity and tritium were collected at judgmentally selected locations on the walls and pedestals of the Fan House foundation. Attention was given to joints, cracks, and penetrations when determining each sample location. Removable concentrations ranged from -0.43 to 1.73 dpm/100 cm2 for alpha and -3.64 to 7.80 dpm/100 cm2 for beta. Tritium results for smears ranged from -1.9 to 9.0 pCi/g. On the concrete pad, 100% of accessible area was scanned using a large area alpha plus beta gas proportional detector coupled to a ratemeter-scaler. Gross scan count rates ranged from 800 to 1500 cpm using the large area detector. Three concrete samples were collected from the pad primarily for tritium analysis. Tritium concentrations in concrete samples ranged from 53.3 to 127.5 pCi/g. Gamma spectroscopy results of radionuclide concentrations in concrete samples ranged from 0.02 to 0.11 pCi/g for Cs-137 and 0.19 to 0.22 pCi/g for Ra-226. High density scans for gamma radiation levels were performed in accessible areas in each SU, Fan House

  13. Final Report Independent Verification Survey of the High Flux Beam Reactor, Building 802 Fan House Brookhaven National Laboratory Upton, New York

    Energy Technology Data Exchange (ETDEWEB)

    Harpeneau, Evan M. [Oak Ridge Institute for Science and Education, Oak Ridge, TN (United States). Independent Environmental Assessment and Verification Program

    2011-06-24

    On May 9, 2011, ORISE conducted verification survey activities including scans, sampling, and the collection of smears of the remaining soils and off-gas pipe associated with the 802 Fan House within the HFBR (High Flux Beam Reactor) Complex at BNL. ORISE is of the opinion, based on independent scan and sample results obtained during verification activities at the HFBR 802 Fan House, that the FSS (final status survey) unit meets the applicable site cleanup objectives established for as left radiological conditions.

  14. Final Report - Independent Verification Survey of the High Flux Beam Reactor, Building 802 Fan House Brookhaven National Laboratory Upton, New York

    International Nuclear Information System (INIS)

    On May 9, 2011, ORISE conducted verification survey activities including scans, sampling, and the collection of smears of the remaining soils and off-gas pipe associated with the 802 Fan House within the HFBR (High Flux Beam Reactor) Complex at BNL. ORISE is of the opinion, based on independent scan and sample results obtained during verification activities at the HFBR 802 Fan House, that the FSS (final status survey) unit meets the applicable site cleanup objectives established for as left radiological conditions

  15. PROJECT-SPECIFIC TYPE A VERIFICATION FOR THE HIGH FLUX BEAM REACTOR UNDERGROUND UTILITIES REMOVAL PHASE 2 D/F WASTE LINE REMOVAL, BROOKHAVEN NATIONAL LABORATORY UPTON, NEW YORK

    International Nuclear Information System (INIS)

    Oak Ridge Institute for Science and Education (ORISE) has reviewed the project documentation and data for the High Flux Beam Reactor (HFBR) Underground Utilities removal Phase 2; the D/F Waste Line removal at Brookhaven National Laboratory (BNL) in Upton, New York. The Brookhaven Survey Group (BSG) has completed removal and performed the final status survey (FSS) of the D/F Waste Line that provided the conduit for pumping waste from Building 750 to Building 801. Sample results have been submitted as required to demonstrate that the cleanup goals of 15 mrem/yr above background to a resident in 50 years have been met. Four rounds of sampling, from pre-excavation to final status survey (FSS), were performed as specified in the Field Sampling Plan (FSP) (BNL 2010a). It is the policy of the US Departmental of Energy (DOE) to perform independent verifications of decontamination and decomissioning activities conducted at DOE facilities. ORISE has been designated as the organization responsible for this task at the HFBR. ORISE together with DOE determined that a Type A verification of the D/F Waste Line was appropriate based on its method of construction and upon the minimal potential for residual radioactivity in the area. The removal of underground utilities is being performed in three stages in the process to decommission the HFBR facility and support structures. Phase 2 of this project included the grouting and removal of 1100 feet of 2-inch pipe and 640 feet of 4-inch pipe that served as the D/F Waste Line. Based on the pre-excavation sample results of the soil overburden, the potential for contamination of the soil surrounding the pipe is minimal (BNL 2010a). ORISE reviewed the BNL FSP and identified comments for consideration (ORISE 2010). BNL prepared a revised FSP that addressed each ORISE comment adequately (BNL 2010a). ORISE referred to the revised Phase 2 D/F Waste Line removal FSP FSS data to conduct the Type A verification and determine whether the intent odf

  16. SUMMARY AND RESULTS LETTER REPORT - INDEPENDENT VERIFICATION OF THE HIGH FLUX BEAM REACTOR UNDERGROUND UTILITIES REMOVAL PROJECT, PHASE 3: TRENCHES 2, 3, AND 4 BROOKHAVEN NATIONAL LABORATORY UPTON, NEW YORK

    International Nuclear Information System (INIS)

    Oak Ridge Institute for Science and Education (ORISE) personnel visited the Brookhaven National Laboratory (BNL) on September 7 through September 10, 2010, and September 20 through Seeptember 24, 2010. ORISE performed visual inspections, conducted independent measurement, and sampling of Trenches 2, 3, and 4, which are part of Phase 3 for the High Flux Beam Reactor (HFBR) Underground Utilities Removal Project. Trenches 2 and 3 were addressed during the first visit and Trench 4 during the second visit to BNL. Spatial orientation to Building 801 and minimal survey area inside Trenches 2 and 3 limited satellite reception and the ability to utilize a global positioning system (GPS) as real-time data capture for the gamma scan surveys in these trenches. However, Trench 4 provided suitable conditions in which gamma scan data could be collected using the GPS. ORISE performed high-density gamma scans of accessible surface areas using shielded sodium iodide detectors coupled to ratemeter-scalers with audible output. Scans for Trench 2 ranged from 4,000 to 22,000 gross counts per minute (cpm); Trench 3 from 3,000 to 5,000 gross cpm and Trench 4 from 2,600 to 9,500 gross cpm. ORISE personnel flagged the area where the elevated counts were observed in Trench 2 for further investigation. Additional scane valuations were performed on remaining pipes and associated end-caps in the trenches with no elevated activity detected. Eleven judgemental soil samples (5098M0041 through 5098M0051) were obtained throughout Trenches 2, 3, and 4. The sample locations were selected based on count rates observed during the scan survey or because of contamination potential from pipeline removal activities. ORISE personnel judgmentally selected the location for sample M0043 in response to the 22,000 cpm observed during the scan survey, and to ascertain whether the elevataed counts were a result of soil contamination or radioactive shine from the trench's spatial orientation to the Target Room in

  17. High energy physics at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    The high energy plans at BNL are centered around the AGS and ISABELLE, or a variant thereof. At present the AGS is maintaining a strong and varied program. This last year a total of 4 x 1019 protons were delivered on target in a period of approximately 20 weeks. Physics interest is very strong, half of the submitted proposals are rejected (thereby maintaining high quality experiments) and the program is full over the next two years. The future colliding beam facility will utilize the AGS as an injector and will be a dedicated facility. It will have six intersection regions, run > 107 sec/year, and explore a new domain of energy and luminosity. Common to all the considered alternatives is a large aperture proton ring. These possible choices involve pp, ep, and heavy ion variants. The long term philosophy is to run the AGS as much as possible, continuously to upgrade it in performance and reliability, and then to phase it down as the new collider begins operation

  18. Brookhaven highlights

    International Nuclear Information System (INIS)

    This publication provides a broad overview of the research programs and efforts being conducted, built, designed, and planned at Brookhaven National Laboratory. This work covers a broad range of scientific disciplines. Major facilities include the Alternating Gradient Synchrotron (AGS), with its newly completed booster, the National Synchrotron Light Source (NSLS), the High Flux Beam Reactor (HFBR), and the RHIC, which is under construction. Departments within the laboratory include the AGS department, accelerator development, physics, chemistry, biology, NSLS, medical, nuclear energy, and interdepartmental research efforts. Research ranges from the pure sciences, in nuclear physics and high energy physics as one example, to environmental work in applied science to study climatic effects, from efforts in biology which are a component of the human genome project to the study, production, and characterization of new materials. The paper provides an overview of the laboratory operations during 1992, including staffing, research, honors, funding, and general laboratory plans for the future

  19. Brookhaven highlights

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.S.; Cohen, A.; Greenberg, D.; Seubert, L. (eds.)

    1992-01-01

    This publication provides a broad overview of the research programs and efforts being conducted, built, designed, and planned at Brookhaven National Laboratory. This work covers a broad range of scientific disciplines. Major facilities include the Alternating Gradient Synchrotron (AGS), with its newly completed booster, the National Synchrotron Light Source (NSLS), the High Flux Beam Reactor (HFBR), and the RHIC, which is under construction. Departments within the laboratory include the AGS department, accelerator development, physics, chemistry, biology, NSLS, medical, nuclear energy, and interdepartmental research efforts. Research ranges from the pure sciences, in nuclear physics and high energy physics as one example, to environmental work in applied science to study climatic effects, from efforts in biology which are a component of the human genome project to the study, production, and characterization of new materials. The paper provides an overview of the laboratory operations during 1992, including staffing, research, honors, funding, and general laboratory plans for the future.

  20. Brookhaven leak reactor to close

    CERN Multimedia

    MacIlwain, C

    1999-01-01

    The DOE has announced that the High Flux Beam Reactor at Brookhaven is to close for good. Though the news was not unexpected researchers were angry the decision had been taken before the review to assess the impact of reopening the reactor had been concluded (1 page).

  1. HFBR handbook, 1992: High flux beam reactor

    International Nuclear Information System (INIS)

    Welcome to the High Flux Beam Reactor (HFBR), one of the world premier neutron research facilities. This manual is intended primarily to acquaint outside users (and new Brookhaven staff members) with (almost) everything they need to know to work at the HFBR and to help make the stay at Brookhaven pleasant as well as profitable. Safety Training Programs to comply with US Department of Energy (DOE) mandates are in progress at BNL. There are several safety training requirements which must be met before users can obtain unescorted access to the HFBR. The Reactor Division has prepared specific safety training manuals which are to be sent to experimenters well in advance of their expected arrival at BNL to conduct experiments. Please familiarize yourself with this material and carefully pay strict attention to all the safety and security procedures that are in force at the HFBR. Not only your safety, but the continued operation of the facility, depends upon compliance

  2. High field magnet program at Brookhaven National Laboratory

    CERN Document Server

    Ghosh, A; Muratore, J; Parker, B; Sampson, W; Wanderer, P J; Willen, E

    2000-01-01

    The magnet program at Brookhaven National Laboratory (BNL) is focussed on superconducting magnets for particle accelerators. The effort includes magnet production at the laboratory and in industry, magnet R&D, and test facilities for magnets and superconductors. Nearly 2000 magnets-dipoles, quadrupoles, sextupoles and correctors for the arc and insertion regions-were produced for the Relativistic Heavy Ion Collider (RHIC), which is being commissioned. Currently, production of helical dipoles for the polarized proton program at RHIC, insertion region dipoles for the Large Hadron Collider (LHC) at CERN, and an insertion magnet system for the Hadron-Elektron-Ring- Analage (HERA) collider at Deutsches Elektronen-Synchrotron (DESY) is underway. The R&D effort is exploring dipoles with fields above 10 T for use in post-LHC colliders. Brittle superconductors-Nb/sub 3/Sn or HTS-are being used for these magnets. The superconductor test facility measures short-sample currents and other characteristics of sample...

  3. Initial experiments with the Nevis Cyclotron, the Brookhaven Cosmotron, the Brookhaven AGS and their effects on high energy physics

    International Nuclear Information System (INIS)

    The first experiment at the Nevis Cyclotron by Bernardini, Booth and Lindenbaum demonstrated that nuclear stars are produced by a nucleon-nucleon cascade within the nucleon. This solved a long standing problem in Cosmic rays and made it clear that where they overlap cosmic ray investigation would not be competitive with accelerator investigations. The initial experiments at the Brookhaven Cosmotron by Lindenbaum and Yuan demonstrated that low energy pion nucleon scattering and pion production were unexpectedly mostly due to excitation of the isotopic spin = angular momentum = 3/2 isobaric state of the nucleon. This contradicted the Fermi statistical theory and led to the Isobar model proposed by the author and a collaborator. The initial experiments at the AGS by the author and collaborators demonstrated that the Pomeronchuck Theorem would not come true till at least several hundred GeV. These scattering experiments led to the development of the ''On-line Computer Technique'' by the author and collaborators which is now the almost universal technique in high energy physics. The first accomplishment which flowed from this technique led to contradiction of the Regge pole theory as a dynamical asymptotic theory, by the author and collaborators. The first critical experimental proof of the forward dispersion relation in strong interactions was accomplished by the author and collaborators. They were then used as a crystal ball to predict that ''Asymptopia''---the theoretically promised land where all asymptotic theorems come true---would not be reached till at least 25,000 BeV and probably not before 1,000,000 BeV. 26 refs., 11 figs., 2 tabs

  4. Brookhaven segment interconnect

    International Nuclear Information System (INIS)

    We have performed a high energy physics experiment using a multisegment Brookhaven FASTBUS system. The system was composed of three crate segments and two cable segments. We discuss the segment interconnect module which permits communication between the various segments

  5. Status of high current R and D Energy Recovery LINAC at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    An ampere class 20 MeV superconducting Energy Recovery Linac (ERL) is under construction at Brookhaven National Laboratory (BNL) for testing of concepts relevant for high-energy coherent electron cooling and electron-ion colliders. One of the goals is to demonstrate an electron beam with high charge per bunch (∼ 5 nC) and low normalized emittance (∼ 5 mm-mrad) at an energy of 20 MeV. Flexible lattice of ERL loop provides a test-bed for investigating issues of transverse and longitudinal instabilities, and diagnostics for intense CW e-beam. The superconducting 703 MHz RF photoinjector is considered as an electron source for such a facility. We will start with a straight pass (gun - 5 cell cavity - beam stop) test for the SRF Gun performance studies. Later, we will install and test a novel injection line concept for emittance preservation in a lower energy merger. In this paper we present the status and our plans for construction and commissioning of this facility.

  6. Brookhaven highlights

    International Nuclear Information System (INIS)

    This report highlights the research activities of Brookhaven National Laboratory during the period dating from October 1, 1992 through September 30, 1993. There are contributions to the report from different programs and departments within the laboratory. These include technology transfer, RHIC, Alternating Gradient Synchrotron, physics, biology, national synchrotron light source, applied science, medical science, advanced technology, chemistry, reactor physics, safety and environmental protection, instrumentation, and computing and communications

  7. Reliable operation of the Brookhaven EBIS for highly charged ion production for RHIC and NSRL

    Science.gov (United States)

    Beebe, E.; Alessi, J.; Binello, S.; Kanesue, T.; McCafferty, D.; Morris, J.; Okamura, M.; Pikin, A.; Ritter, J.; Schoepfer, R.

    2015-01-01

    An Electron Beam Ion Source for the Relativistic Heavy Ion Collider (RHIC EBIS) was commissioned at Brookhaven in September 2010 and since then it routinely supplies ions for RHIC and NASA Space Radiation Laboratory (NSRL) as the main source of highly charged ions from Helium to Uranium. Using three external primary ion sources for 1+ injection into the EBIS and an electrostatic injection beam line, ion species at the EBIS exit can be switched in 0.2 s. A total of 16 different ion species have been produced to date. The length and the capacity of the ion trap have been increased by 20% by extending the trap by two more drift tubes, compared with the original design. The fraction of Au32+ in the EBIS Au spectrum is approximately 12% for 70-80% electron beam neutralization and 8 pulses operation in a 5 Hertz train and 4-5 s super cycle. For single pulse per super cycle operation and 25% electron beam neutralization, the EBIS achieves the theoretical Au32+ fractional output of 18%. Long term stability has been very good with availability of the beam from RHIC EBIS during 2012 and 2014 RHIC runs approximately 99.8%.

  8. Reliable operation of the Brookhaven EBIS for highly charged ion production for RHIC and NSRL

    International Nuclear Information System (INIS)

    An Electron Beam Ion Source for the Relativistic Heavy Ion Collider (RHIC EBIS) was commissioned at Brookhaven in September 2010 and since then it routinely supplies ions for RHIC and NASA Space Radiation Laboratory (NSRL) as the main source of highly charged ions from Helium to Uranium. Using three external primary ion sources for 1+ injection into the EBIS and an electrostatic injection beam line, ion species at the EBIS exit can be switched in 0.2 s. A total of 16 different ion species have been produced to date. The length and the capacity of the ion trap have been increased by 20% by extending the trap by two more drift tubes, compared with the original design. The fraction of Au32+ in the EBIS Au spectrum is approximately 12% for 70-80% electron beam neutralization and 8 pulses operation in a 5 Hertz train and 4-5 s super cycle. For single pulse per super cycle operation and 25% electron beam neutralization, the EBIS achieves the theoretical Au32+ fractional output of 18%. Long term stability has been very good with availability of the beam from RHIC EBIS during 2012 and 2014 RHIC runs approximately 99.8%

  9. Brookhaven Highlights, January 1982-March 1983

    Energy Technology Data Exchange (ETDEWEB)

    Kuper, J.B.H.; Rustad, M.C. (eds.)

    1983-01-01

    Research at Brookhaven National Laboratory is summarized. Major headings are high energy physics, physics and chemistry, life sciences, applied energy science, support activities and administration. (GHT)

  10. Extraterrestrial high energy neutrino fluxes

    International Nuclear Information System (INIS)

    With the aid of using the most recent cosmic ray spectra up to 2x1020 eV, production spectra of high-energy neutrinos from cosmic ray interactions with interstellar gas and extragalactic interactions of ultrahigh-energy cosmic rays with 3K universal background photons are presented and discussed. Estimates of the fluxes from cosmic diffuse sources and the nearby quasar 3C273 are made using the generic relationship between secondary neutrinos and gammas and using recent gamma ray satellite data. These gamma ray data provide important upper limits on cosmological neutrinos. Quantitative estimates of the observability of high-energy neutrinos from the inner galaxy and 3C273 above atmospheric background for a DUMAND-type detector are discussed in the context of the Weinberg-Salam model with sin2 theta/sub ω/ = 0.2 and including the atmospheric background from the decay of charmed mesons. Constraints on cosmological high-energy neutrino production models are also discussed. It appears that important high-energy neutrino astronomy may be possible with DUMAND, but very long observing times are required

  11. Extraterrestrial high energy neutrino fluxes

    Science.gov (United States)

    Stecker, F. W.

    1979-01-01

    Using the most recent cosmic ray spectra up to 2x10 to the 20th power eV, production spectra of high energy neutrinos from cosmic ray interactions with interstellar gas and extragalactic interactions of ultrahigh energy cosmic rays with 3K universal background photons are presented and discussed. Estimates of the fluxes from cosmic diffuse sources and the nearby quasar 3C273 are made using the generic relationship between secondary neutrinos and gammas and using recent gamma ray satellite data. These gamma ray data provide important upper limits on cosmological neutrinos. Quantitative estimates of the observability of high energy neutrinos from the inner galaxy and 3C273 above atmospheric background for a DUMAND type detector are discussed in the context of the Weinberg-Salam model with sq sin theta omega = 0.2 and including the atmospheric background from the decay of charmed mesons. Constraints on cosmological high energy neutrino production models are also discussed. It appears that important high energy neutrino astronomy may be possible with DUMAND, but very long observing times are required.

  12. Extraterrestrial high energy neutrino fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Stecker, F.W.

    1979-06-01

    With the aid of using the most recent cosmic ray spectra up to 2x10/sup 20/ eV, production spectra of high-energy neutrinos from cosmic ray interactions with interstellar gas and extragalactic interactions of ultrahigh-energy cosmic rays with 3K universal background photons are presented and discussed. Estimates of the fluxes from cosmic diffuse sources and the nearby quasar 3C273 are made using the generic relationship between secondary neutrinos and gammas and using recent gamma ray satellite data. These gamma ray data provide important upper limits on cosmological neutrinos. Quantitative estimates of the observability of high-energy neutrinos from the inner galaxy and 3C273 above atmospheric background for a DUMAND-type detector are discussed in the context of the Weinberg-Salam model with sin/sup 2/ theta/sub ..omega../ = 0.2 and including the atmospheric background from the decay of charmed mesons. Constraints on cosmological high-energy neutrino production models are also discussed. It appears that important high-energy neutrino astronomy may be possible with DUMAND, but very long observing times are required.

  13. Advanced high temperature heat flux sensors

    Science.gov (United States)

    Atkinson, W.; Hobart, H. F.; Strange, R. R.

    1983-01-01

    To fully characterize advanced high temperature heat flux sensors, calibration and testing is required at full engine temperature. This required the development of unique high temperature heat flux test facilities. These facilities were developed, are in place, and are being used for advanced heat flux sensor development.

  14. Design and Fabrication of a Highly Integrated Silicon Detector for the STAR Experiment at Brookhaven National Laboratory

    CERN Document Server

    Buck, Benjamin; Bessuille, Jason; Cepeda, Mario; Johnson, Thomas; Kelsey, James; van Nieuwenhuizen, Gerrit; Visser, Gerard

    2014-01-01

    We present the design of a detector used as a particle tracking device in the STAR experiment at the RHIC collider of Brookhaven National Laboratories. The "stave," 24 of which make up the completed detector, is a highly mechanically integrated design comprised of 6 custom silicon sensors mounted on a Kapton substrate. 4608 wire bonds connect these sensors to 36 analog front-end chips which are mounted on the same substrate. Power and signal connectivity from the hybrid to the front-end chips is provided by wire bonds. The entire circuit is mounted on a carbon fiber base co-cured to the Kapton substrate. We present the unique design challenges for this detector and some novel techniques for overcoming them.

  15. High Flux Isotope Reactor (HFIR)

    Data.gov (United States)

    Federal Laboratory Consortium — The HFIR at Oak Ridge National Laboratory is a light-water cooled and moderated reactor that is the United States’ highest flux reactor-based neutron source. HFIR...

  16. Flux flow and flux dynamics in high-Tc superconductors

    Science.gov (United States)

    Bennett, L. H.; Turchinskaya, M.; Swartzendruber, L. J.; Roitburd, A.; Lundy, D.; Ritter, J.; Kaiser, D. L.

    1991-01-01

    Because high temperature superconductors, including BYCO and BSSCO, are type 2 superconductors with relatively low H(sub c 1) values and high H(sub c 2) values, they will be in a critical state for many of their applications. In the critical state, with the applied field between H(sub c 1) and H(sub c 2), flux lines have penetrated the material and can form a flux lattice and can be pinned by structural defects, chemical inhomogeneities, and impurities. A detailed knowledge of how flux penetrates the material and its behavior under the influence of applied fields and current flow, and the effect of material processing on these properties, is required in order to apply, and to improve the properties of these superconductors. When the applied field is changed rapidly, the time dependence of flux change can be divided into three regions, an initial region which occurs very rapidly, a second region in which the magnetization has a 1n(t) behavior, and a saturation region at very long times. A critical field is defined for depinning, H(sub c,p) as that field at which the hysteresis loop changes from irreversible to reversible. As a function of temperature, it is found that H(sub c,p) is well described by a power law with an exponent between 1.5 and 2.5. The behavior of H(sub c,p) for various materials and its relationship to flux flow and flux dynamics are discussed.

  17. Flux flow and flux dynamics in high-Tc superconductors

    International Nuclear Information System (INIS)

    Because high temperature superconductors, including BYCO and BSSCO, are type 2 superconductors with relatively low H(sub c 1) values and high H(sub c 2) values, they will be in a critical state for many of their applications. In the critical state, with the applied field between H(sub c 1) and H(sub c 2), flux lines have penetrated the material and can form a flux lattice and can be pinned by structural defects, chemical inhomogeneities, and impurities. A detailed knowledge of how flux penetrates the material and its behavior under the influence of applied fields and current flow, and the effect of material processing on these properties, is required in order to apply, and to improve the properties of these superconductors. When the applied field is changed rapidly, the time dependence of flux change can be divided into three regions, an initial region which occurs very rapidly, a second region in which the magnetization has a 1n(t) behavior, and a saturation region at very long times. A critical field is defined for depinning, H(sub c,p) as that field at which the hysteresis loop changes from irreversible to reversible. As a function of temperature, it is found that H(sub c,p) is well described by a power law with an exponent between 1.5 and 2.5. The behavior of H(sub c,p) for various materials and its relationship to flux flow and flux dynamics are discussed

  18. Brookhaven highlights, fiscal year 1985, October 1, 1984-September 30, 1985

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    Activities at Brookhaven National Laboratory are briefly discussed. These include work at the National Synchrotron Light Source, the High Flux Beam Reactor, and the Alternating Gradient Synchrotron. Areas of research include heavy ion reactions, neutrino oscillations, low-level waste, nuclear data, medicine, biology, chemistry, parallel computing, optics. Also provided are general and administrative news, a financial report. (LEW)

  19. Brookhaven highlights, fiscal year 1985, October 1, 1984-September 30, 1985

    International Nuclear Information System (INIS)

    Activities at Brookhaven National Laboratory are briefly discussed. These include work at the National Synchrotron Light Source, the High Flux Beam Reactor, and the Alternating Gradient Synchrotron. Areas of research include heavy ion reactions, neutrino oscillations, low-level waste, nuclear data, medicine, biology, chemistry, parallel computing, optics. Also provided are general and administrative news, a financial report

  20. The Brookhaven Accelerator Test Facility

    International Nuclear Information System (INIS)

    The Accelerator Test Facility (ATF), presently under construction at Brookhaven National laboratory, is described. It consists of a 50-MeV electron beam synchronizable to a high-peak power CO2 laser. The interaction of electrons with the laser field will be probed, with some emphasis on exploring laser-based acceleration techniques. 5 refs., 2 figs

  1. Flux attenuation at NREL's High-Flux Solar Furnace

    Science.gov (United States)

    Bingham, Carl E.; Scholl, Kent L.; Lewandowski, Allan A.

    1994-10-01

    The High-Flux Solar Furnace (HFSF) at the National Renewable Energy Laboratory (NREL) has a faceted primary concentrator and a long focal-length-to-diameter ratio (due to its off-axis design). Each primary facet can be aimed individually to produce different flux distributions at the target plane. Two different types of attenuators are used depending on the flux distribution. A sliding-plate attenuator is used primarily when the facets are aimed at the same target point. The alternate attenuator resembles a venetian blind. Both attenuators are located between the concentrator and the focal point. The venetian-blind attenuator is primarily used to control the levels of sunlight failing on a target when the primary concentrators are not focused to a single point. This paper will demonstrate the problem of using the sliding-plate attenuator with a faceted concentrator when the facets are not aimed at the same target point. We will show that although the alternate attenuator necessarily blocks a certain amount of incoming sunlight, even when fully open, it provides a more even attenuation of the flux for alternate aiming strategies.

  2. Brookhaven highlights, October 1978-September 1979

    International Nuclear Information System (INIS)

    These highlights present an overview of the major research and development achievements at Brookhaven National Laboratory from October 1978 to September 1979. Specific areas covered include: accelerator and high energy physics programs; high energy physics research; the AGS and improvements to the AGS; neutral beam development; heavy ion fusion; superconducting power cables; ISABELLE storage rings; the BNL Tandem accelerator; heavy ion experiments at the Tandem; the High Flux Beam Reactor; medium energy physics; nuclear theory; atomic and applied physics; solid state physics; neutron scattering studies; x-ray scattering studies; solid state theory; defects and disorder in solids; surface physics; the National Synchrotron Light Source ; Chemistry Department; Biology Department; Medical Department; energy sciences; environmental sciences; energy technology programs; National Center for Analysis of Energy Systems; advanced reactor systems; nuclear safety; National Nuclear Data Center; nuclear materials safeguards; Applied Mathematics Department; and support activities

  3. Brookhaven National Laboratory ADS concepts (USA)

    International Nuclear Information System (INIS)

    Three types of accelerator driven system have been investigated at Brookhaven National Laboratory: the accelerator driven energy producer (ADEP) which is intended for energy production, incineration of minor actinides (MA) and long-lived fission products (LLFP) using a small power accelerator; the Phoenix concept aimed at transmuting large amounts of MA and LLFP using a high current linear accelerator; the accelerator driven particle fuel transmutor (ADPF) which also transmutes the MA and LLFP at high rate by using a high neutron flux. The paper presents these three concepts and other related problems such as fuel and coolant materials, targets, subcriticality and safety issues, the use of Thorium cycle, and non-proliferation issue

  4. Brookhaven highlights - Brookhaven National Laboratory 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    This report highlights research conducted at Brookhaven National Laboratory in the following areas: alternating gradient synchrotron; physics; biology; national synchrotron light source; department of applied science; medical; chemistry; department of advanced technology; reactor; safety and environmental protection; instrumentation; and computing and communications.

  5. High flux expansion divertor studies in NSTX

    CERN Document Server

    Soukhanovskii, V A; Bell, R E; Gates, D A; Kaita, R; Kugel, H W; LeBlanc, B P; Maqueda, R; Menard, J E; Mueller, D; Paul, S F; Raman, R; Roquemore, A L

    2009-01-01

    High flux expansion divertor studies have been carried out in the National Spherical Torus Experiment using steady-state X-point height variations from 22 to 5-6 cm. Small-ELM H-mode confinement was maintained at all X-point heights. Divertor flux expansions from 6 to 26-28 were obtained, with associated reduction in X-point connection length from 5-6 m to 2 m. Peak divertor heat flux was reduced from 7-8 MW/m$^2$ to 1-2 MW/m$^2$. In low X-point configuration, outer strike point became nearly detached. Among factors affecting deposition of parallel heat flux in the divertor, the flux expansion factor appeared to be dominant

  6. Brookhaven fastbus/unibus interface

    Energy Technology Data Exchange (ETDEWEB)

    Benenson, G.; Bauernfeind, J.; Larsen, R.C.; Leipuner, L.B.; Morse, W.M.; Adair, R.K.; Black, J.K.; Campbell, S.R.; Kasha, H.; Schmidt, M.P.

    1983-01-01

    A typical high energy physics experiment requires both a high speed data acquisition and processing system, for data collection and reduction; and a general purpose computer to handle further reduction, bookkeeping and mass storage. Broad differences in architecture, format or technology, will often exist between these two systems, and interface design can become a formidable task. The PDP-11 series minicomputer is widely used in physics research, and the Brookhaven FASTBUS is the only standard high speed data acquisition system which is fully implemented in a current high energy physics experiment. This paper will describe the design and operation of an interface between these two systems. The major issues are elucidated by a preliminary discussion on the basic principles of Bus Systems, and their application to Brookhaven FASTBUS and UNIBUS.

  7. Brookhaven fastbus/unibus interface

    International Nuclear Information System (INIS)

    A typical high energy physics experiment requires both a high speed data acquisition and processing system, for data collection and reduction; and a general purpose computer to handle further reduction, bookkeeping and mass storage. Broad differences in architecture, format or technology, will often exist between these two systems, and interface design can become a formidable task. The PDP-11 series minicomputer is widely used in physics research, and the Brookhaven FASTBUS is the only standard high speed data acquisition system which is fully implemented in a current high energy physics experiment. This paper will describe the design and operation of an interface between these two systems. The major issues are elucidated by a preliminary discussion on the basic principles of Bus Systems, and their application to Brookhaven FASTBUS and UNIBUS

  8. Barrier Cavities in the Brookhaven AGS

    International Nuclear Information System (INIS)

    In collaboration with KEK two barrier cavities, each generating 40 kV per turn have been installed in the Brookhaven AGS. Machine studies are described and their implications for high intensity operations are discussed

  9. RHIC: The World's First High-Energy, Polarized-Proton Collider (423rd Brookhaven Lecture)

    International Nuclear Information System (INIS)

    The Relativistic Heavy Ion Collider (RHIC) at BNL has been colliding polarized proton at a beam energy of 100 billion electron volts (GeV) since 2001. In addition to reporting upon the progress of RHIC polarized-proton program, this talk will focus upon the mechanisms that cause the beam to depolarize and the strategies developed to overcome this. As the world first polarized-proton collider, RHIC is designed to collide polarized protons up to an energy of 250 GeV, thereby providing an unique opportunity to measure the contribution made by the gluon to a proton's spin and to study the spin structure of proton. Unlike other high-energy proton colliders, however, the challenge for RHIC is to overcome the mechanisms that cause partial or total loss of beam polarization, which is due to the interaction of the spin vector with the magnetic fields. In RHIC, two Siberian snakes have been used to avoid these spin depolarizing resonances, which are driven by vertical closed-orbit distortion and vertical betatron oscillations. As a result, polarized-proton beams have been accelerated to 100 GeV without polarization loss, although depolarization has been observed during acceleration from 100 GeV to 205 GeV.

  10. High flux source of cold rubidium atoms

    International Nuclear Information System (INIS)

    We report on the production of a continuous, slow, and cold beam of 87Rb atoms with an extremely high flux of 3.2x1012 atoms/s, a transverse temperature of 3 mK, and a longitudinal temperature of 90 mK. We describe the apparatus created to generate the atom beam. Hot atoms are emitted from a rubidium candlestick atomic beam source and transversely cooled and collimated by a 20 cm long atomic collimator section, boosting overall beam flux by a factor of 50. The Rb atomic beam is then decelerated and longitudinally cooled by a 1 m long Zeeman slower

  11. High flux source of cold rubidium atoms

    Science.gov (United States)

    Slowe, Christopher; Vernac, Laurent; Hau, Lene Vestergaard

    2005-10-01

    We report on the production of a continuous, slow, and cold beam of Rb87 atoms with an extremely high flux of 3.2×1012atoms/s, a transverse temperature of 3mK, and a longitudinal temperature of 90mK. We describe the apparatus created to generate the atom beam. Hot atoms are emitted from a rubidium candlestick atomic beam source and transversely cooled and collimated by a 20cm long atomic collimator section, boosting overall beam flux by a factor of 50. The Rb atomic beam is then decelerated and longitudinally cooled by a 1m long Zeeman slower.

  12. EU Development of High Heat Flux Components

    OpenAIRE

    Linke, J.; Lorenzetto, P.; Majerus, P.; Merola, M.; Pitzer, D.; Rödig, M.

    2005-01-01

    The development of plasma facing components for next step fusion devices in Europe is strongly focused to ITER. Here a wide spectrum of different design options for the divertor target and the first wall have been investigated with tungsten, CFC, and beryllium armor. Electron beam simulation experiments have been used to determine the performance of high heat flux components under ITER specific thermal loads. Beside thermal fatigue loads with power density levels up to 20MWm(-2), off normal e...

  13. BROOKHAVEN: Booster commissioned

    International Nuclear Information System (INIS)

    The construction and first commissioning phase of the Booster synchrotron to inject into Brookhaven's veteran Alternating Gradient Synchrotron (AGS) were completed last year. Scheduled to come into operation this year, the new Booster will extend the research capabilities AGS, and with its ability to accelerate partially stripped heavy ions will play an essential role in the chain of accelerators serving the Relativistic Heavy Ion Collider (RHIC)

  14. Burnout at very high heat fluxes

    International Nuclear Information System (INIS)

    The paper provides a brief overview of the present state-of-the art in the field of the critical heat flux (CHF) in subcooled flow conditions, with particular regard to high liquid velocity and highly subcooled conditions. These thermofluid-high values of the CHF (dynamic conditions to reach very (up to 80 MW/m2) as requested by fusion technology requirements. After reporting the general feature of the problems, some details are given about the main parameters affecting CHF in subcooled flow boiling (subcooling, pressure, duct diameter and length, fluid velocity, duct orientation and flow direction, heat flux distribution), and the respective knowledge and possible enhancement techniques for CHF (extended surfaces, hypervapotron, surface roughness, swirl flow, helically coiled wires) are reviewed. As fundamental aspects of highly subcooled flow boiling are not known and, on the other hand, such knowledge is necessary for any possible enhancement technique evalutation and for a theoretical modelling of the phenomenon, recent experiments carried out over the last five years on CHF in subcooled flow boiling are reviewed together with the main correlations and models curently used for data prediction, and suggestions for particular and general research guidelines are given. (orig.)

  15. Brookhaven highlights, October 1979-September 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    Highlights are given for the research areas of the Brookhaven National Laboratory. These areas include high energy physics, physics and chemistry, life sciences, applied energy science (energy and environment, and nuclear energy), and support activities (including mathematics, instrumentation, reactors, and safety). (GHT)

  16. Brookhaven highlights, October 1979-September 1980

    International Nuclear Information System (INIS)

    Highlights are given for the research areas of the Brookhaven National Laboratory. These areas include high energy physics, physics and chemistry, life sciences, applied energy science (energy and environment, and nuclear energy), and support activities (including mathematics, instrumentation, reactors, and safety)

  17. High-energy fluxes of atmospheric neutrinos

    CERN Document Server

    Sinegovskaya, T S; Sinegovsky, S I

    2013-01-01

    High-energy neutrinos from decays of mesons, produced in collisions of cosmic ray particles with air nuclei, form unavoidable background for detection of astrophysical neutrinos. More precise calculations of the high-energy neutrino spectrum are required since measurements in the IceCube experiment reach the intriguing energy region where a contribution of the prompt neutrinos and/or astrophysical ones should be discovered. Basing on the referent hadronic models QGSJET II-03, SIBYLL 2.1, we calculate high-energy spectra, both of the muon and electron atmospheric neutrinos, averaged over zenith-angles. The computation is made using three parameterizations of cosmic ray spectra which include the knee region. All calculations are compared with the atmospheric neutrino measurements by Frejus and IceCube. The prompt neutrino flux predictions obtained with thequark-gluon string model (QGSM) for the charm production by Kaidalov & Piskunova do not contradict to the IceCube measurements and upper limit on the astr...

  18. BROOKHAVEN: Booster boost

    International Nuclear Information System (INIS)

    After three months of intensive dedicated machine studies, Brookhaven's new Booster accelerated 5 x 1013 protons over four cycles, about 85% of the design intensity. This was made possible by careful matching of Linac beam into the Booster and by extensive resonance stop band corrections implemented during Booster acceleration. The best single cycle injection into the AGS Alternating Gradient Synchrotron was 1.14 x 1013 protons from the Booster. 1.05 x 1013 protons were kept in the AGS, a 92% combined efficiency of extraction, transfer, and injection. The maximum injected 1994 shutdown period, enabling the 1994 physics run to make use of the full Booster intensity and go for the stated AGS objective of 4x1013 protons per pulse

  19. High heat flux engineering in solar energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, C.P.

    1993-07-01

    Solar thermal energy systems can produce heat fluxes in excess of 10,000 kW/m{sup 2}. This paper provides an introduction to the solar concentrators that produce high heat flux, the receivers that convert the flux into usable thermal energy, and the instrumentation systems used to measure flux in the solar environment. References are incorporated to direct the reader to detailed technical information.

  20. A High Flux Source of Cold Rubidium

    CERN Document Server

    Slowe, C; Hau, L V; Slowe, Christopher; Vernac, Laurent; Hau, Lene Vestergaard

    2004-01-01

    We report the production of a continuous, slow, and cold beam of 87-Rb atoms with an unprecedented flux of 3.2 x 10^12 atoms/s and a temperature of a few milliKelvin. Hot atoms are emitted from a Rb candlestick atomic beam source and transversely cooled and collimated by a 20 cm long atomic collimator section, augmenting overall beam flux by a factor of 50. The atomic beam is then decelerated and longitudinally cooled by Zeeman slowing.

  1. Workshop on high heat flux materials for TFCX

    International Nuclear Information System (INIS)

    The workshop reviewed the performance requirements for high-heat-flux material in TFCX, summarized existing materials and materials technologies for meeting these requirements, identified critical near-term materials R and D for high-heat flux components, and reviewed the status of materials test facilities for performing the necessary R and D

  2. The Brookhaven National Laboratory Accelerator Test Facility

    International Nuclear Information System (INIS)

    The Brookhaven National Laboratory Accelerator Test Facility comprises a 50 MeV traveling wave electron linear accelerator utilizing a high gradient, photo-excited, raidofrequency electron gun as an injector and an experimental area for study of new acceleration methods or advanced radiation sources using free electron lasers. Early operation of the linear accelerator system including calculated and measured beam parameters are presented together with the experimental program for accelerator physics and free electron laser studies

  3. Biological Effects of Particles with Very High Energy Deposition on Mammalian Cells Utilizing the Brookhaven Tandem Van de Graaff Accelerator

    Science.gov (United States)

    Saha, Janapriya; Cucinotta, Francis A.; Wang, Minli

    2013-01-01

    High LET radiation from GCR (Galactic Cosmic Rays) consisting mainly of high charge and energy (HZE) nuclei and secondary protons and neutrons, and secondaries from protons in SPE (Solar Particle Event) pose a major health risk to astronauts due to induction of DNA damage and oxidative stress. Experiments with high energy particles mimicking the space environment for estimation of radiation risk are being performed at NASA Space Radiation Laboratory at BNL. Experiments with low energy particles comparing to high energy particles of similar LET are of interest for investigation of the role of track structure on biological effects. For this purpose, we report results utilizing the Tandem Van de Graaff accelerator at BNL. The primary objective of our studies is to elucidate the influence of high vs low energy deposition on track structure, delta ray contribution and resulting biological responses. These low energy ions are of special relevance as these energies may occur following absorption through the spacecraft and shielding materials in human tissues and nuclear fragments produced in tissues by high energy protons and neutrons. This study will help to verify the efficiency of these low energy particles and better understand how various cell types respond to them.

  4. The Brookhaven Radiation Effects Facility

    International Nuclear Information System (INIS)

    The Neutral Particle Beam (NPB) Radiation Effects Facility (REF), funded by the Strategic Defense Initiative Office (SDIO) through the Defense Nuclear Agency (DNA) and the Air Force Weapons Laboratory (AFWL), has been constructed at Brookhaven National Laboratory (BNL). Operation started in October 1986. The facility is capable of delivering pulsed H-, H/sup o/, and H+ beams of 100 to 200 MeV energy up to 30 mA peak current. Pulses can be adjusted from 5 μs to 500 μs length at a repetition rate of 5 pps. The beam spot on target is adjustable from 3 to 100 cm diameter (2 σ) resulting in a maximum dose of about 10 MRads (Si) per pulse (small beam spot). Experimental use of the REF is being primarily supported by the SDI lethality (LTH-4) program. The program has addressed ionization effects in electronics, both dose rate and total dose dependence, radiation-sensitive components, and dE/dx effects in energetic materials including propellants and high explosives (HE). This paper describes the facility, its capabilities and potential, and the experiments that have been carried out to date or are being planned. 2 refs., 10 figs

  5. Response of actinides to flux changes in high-flux systems

    International Nuclear Information System (INIS)

    When discussing the transmutation of actinides in accelerator-based transmutation of waste (ATW) systems, there has been some concern about the dynamics of the actinides under high transient fluxes. For a pure neptunium feed, it has been estimated that the 238Np/237Np ratio increase due to an increasing flux may lead to an unstable, positive reactivity growth. In this analysis, a perturbation method is used to calculate the response of the entire set of actinides in a general way that allows for more species than just neptunium. The time response of the system can be calculated; i.e., a plot of fuel composition and reactivity versus time after a change in flux can be made. The effects of fission products can also be included. The procedure is extremely accurate on short time scales (∼ 1000 s) for the flux levels we contemplate. Calculational results indicate that the reactivity insertions are always smaller than previously estimated

  6. Tensile and impact testing of an HFBR [High Flux Beam Reactor] control rod follower

    International Nuclear Information System (INIS)

    The Materials Technology Group of the Department of Nuclear Energy (DNE) at Brookhaven National Laboratory (BNL) undertook a program to machine and test specimens from a control rod follower from the High Flux Beam Reactor (HFBR). Tensile and Charpy impact specimens were machined and tested from non-irradiated aluminum alloys in addition to irradiated 6061-T6 from the HFBR. The tensile test results on irradiated material showed a two-fold increase in tensile strength to a maximum of 100.6 ksi. The impact resistance of the irradiated material showed a six-fold decrease in values (3 in-lb average) compared to similar non-irradiated material. Fracture toughness (KI) specimens were tested on an unirradiated compositionally and dimensionally similar (to HFBR follower) 6061 T-6 material with Kmax values of 24.8 ± 1.0 Ksi√in (average) being obtained. The report concludes that the specimens produced during the program yielded reproducible and believable results and that proper quality assurance was provided throughout the program. 9 figs., 6 tabs

  7. Miniaturized heat flux sensor for high enthalpy plasma flow characterization

    International Nuclear Information System (INIS)

    An improved miniaturized heat flux sensor is presented aiming at measuring extreme heat fluxes of plasma wind tunnel flows. The sensor concept is based on an in-depth thermocouple measurement with a miniaturized design and an advanced calibration approach. Moreover, a better spatial estimation of the heat flux profile along the flow cross section is realized with this improved small sensor design. Based on the linearity assumption, the heat flux is determined using the impulse response of the sensor relating the heat flux to the temperature of the embedded thermocouple. The non-integer system identification (NISI) procedure is applied that allows a calculation of the impulse response from transient calibration measurements with a known heat flux of a laser source. The results show that the new sensor leads to radially highly resolved heat flux measurement for a flow with only a few centimetres in diameter, the so far not understood non-symmetric heat flux profiles do not occur with the new sensor design. It is shown that this former effect is not a physical effect of the flow, but a drawback of the classical sensor design. (authors)

  8. Relation of middle molecules levels and oxidative stress to erythropoietin requirements in high-flux versus low-flux hemodialysis

    Directory of Open Access Journals (Sweden)

    Hala S El-Wakil

    2013-01-01

    Full Text Available The objective of this study is to investigate the serum beta-2-microglobulin (B2MG and advanced oxidation protein products (AOPP as middle molecule uremic toxins and protein carbonyl (PCO as oxidative stress marker in uremic patients undergoing high-flux versus low-flux hemodialysis (HD and to correlate their levels to the erythropoietin requirements for those patients. Twenty patients on chronic low-flux HD were recruited in the study. At the start of the study, all patients underwent high-flux HD for eight weeks, followed by low-flux HD for two weeks as a washout period. The patients were then subjected to another eight weeks of low-flux HD. Blood samples were obtained at the beginning and at the end of the high-flux period and the low-flux period. The mean erythropoietin dose for patients using high-flux HD was significantly lower than that for low-flux HD (P = 0.0062. Post-high flux, the B2MG and PCO levels were significantly lower than the pre-high-flux levels (P = 0.026 and 0.0005, respectively, but no significant change was observed in AOPP (P = 0.68. Post-low flux, the B2MG, AOPP and PCO were significantly higher than the pre-low-flux levels (P = 0.0002, 0.021 and <0.0001, respectively. Post-low flux, the B2MG and PCO were significantly higher than the post-high-flux levels (P <0.0001, but no significant difference was observed in AOPP (P = 0.11. High-flux HD results in reduction of some of the middle molecule toxins and PCO levels better than low-flux HD, and is associated with a better response to erythropoietin.

  9. High Torque Density Transverse Flux Machine without the Need to Use SMC Material for 3D Flux Paths

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Wu, Weimin

    2015-01-01

    This paper presents a new transverse flux permanent magnet machine. In a normal transverse flux machine, complicated 3-D flux paths often exist. Such 3-D flux paths would require the use of soft magnetic composites material instead of laminations for construction of the machine stator. In the new...... machine topology proposed in this paper, by advantageously utilizing the magnetic flux path provided by an additional rotor, use of laminations that allow 2-D flux paths only will be sufficient to accomplish the required 3-D flux paths. The machine also has a high torque density and is therefore an...

  10. Brookhaven highlights, 1986-1987

    International Nuclear Information System (INIS)

    The highlights of research conducted between October 1985 and September 1987 at Brookhaven National Laboratory are reviewed in this publication. Also covered are the administrative and financial status of the laboratory and a brief mention of meetings held and honors received. (FI)

  11. Hypernuclear physics research at Brookhaven

    International Nuclear Information System (INIS)

    This paper describes the results of a recently completed study of the hypernucleus 12/sub Λ/C. The observed formation of hypernuclear states at large momentum is compared with theoretical expectations. Future directions of the research program at Brookhaven are outlined

  12. Flux flow and flux dynamics in high-T(sub c) superconductors

    Science.gov (United States)

    Bennett, L. H.; Turchinskaya, M.; Roytburd, A.; Swartzendruber, L. J.

    1990-01-01

    Because high temperature superconductors, including BYCO and BSCCO, are type 2 superconductors with relatively low H(sub c 1) values and high H(sub c 2) values, they will be in a critical state for many of their applications. In the critical state, with the applied field between H(sub c 1) and H(sub c 2), flux lines have penetrated the material and can form a flux lattice and can be pinned by structural defects, chemical inhomogeneities, and impurities. A detailed knowledge of how flux penetrates the material and its behavior under the influence of applied fields and current flow, and the effect of material processing on these properties, is required in order to apply, and to improve the properties of, these superconductors. When the applied field is changed rapidly, the time dependence of flux change can be divided into three regions, an initial region which occurs very rapidly, a second region in which the magnetization has a 1n(t) behavior, and a saturation region at very long times. A critical field is defined for depinning, H(sub c,p) as that field at which the hysteresis loop changes from irreversible to reversible. As a function of temperature it is found that H(sub c,p) is well described by a power law with an exponent between 1.5 and 2.5. The behavior of H(sub c,p) for various materials and its relationship to flux flow and flux dynamics are discussed.

  13. On the cycle and neutron fluxes of the high flux reactor at ill Grenoble

    International Nuclear Information System (INIS)

    The fuel evolution and neutron fluxes of the high flux reactor at ILL Grenoble were investigated for the full fuel cycle. Two different code systems, namely MONTEBURNS and MCNP + CINDER'90, were employed for a realistic 3-D geometry description of the reactor core and experimental channels of interest. Both codes correctly reproduce the history of the fuel burn-up. Calculated neutron flux in the reactor core is 2.16 x 1015 n/s cm2 gym- and decreases down to 1.65 x 1015 n/s cm2 - and 6.7 x 1014 n/s cm2 in the experimental channels V4 and H9 respectively. Thermal neutron contribution is ∼85.2% in V4 and ∼98.3% in H9. We show that neutron fluxes in the experimental channels V4 and H9 are not perturbed/changed due to the burn-up of the fuel element and/or movement of the control rod. This result should simplify most of the irradiation experiments (and data analysis in particular), which employ the experimental channels as above. (authors)

  14. Control Rods in high-Flux Swimming-Pool Reactors

    International Nuclear Information System (INIS)

    Control-rod problems in open swimming-pool high-flux and high specific power research reactors are examined in the light of the calibrations and experiments made during the construction of the SILOE reactor. Control-rod operating experience for this reactor at 13 MW is also described. 2. The following are considered in turn: (a) Reactivity balances and reactivity values for the different types of rod tested (cadmium, B4C , rare earths and combinations of these different elements). (b) Flux peaks set up in the core by the presence of the control rods, their incidence on the specific power, the fast fluxes that can be obtained and means of increasing them. (c ) The technological problems involved in constructing the rods. (d) In-pile cooling, vibration, deformation and scram-time problems. 3. In conclusion, current studies on control rods in open swimming-pool reactors operating in the 10 - 30 1W range are briefly summarized. (author)

  15. The SINQ project. High flux without enrichment problems?

    International Nuclear Information System (INIS)

    A spallation neutron source (SINQ) designed for operation in a continuous mode is presently under construction at The Paul Scherrer Institute in Switzerland and is scheduled for completion in 1994. The waste beam from an isochronous proton cyclotron which is being upgraded to deliver around 1.5 mA of 590 MeV protons will be used after passing through two targets for meson production. The neutron flux in the D2O moderator surrounding the Pb-Bi spallation target is anticipated to amount to some 1014 n/cm2s per mA of beam current on target. This will put SINQ in the regime of most of the medium flux reactors which are presently being considered for operation with low fuel enrichment. Since SINQ will be the world's first spallation neutron source of that design and power level it is difficult to predict, how far the technology can be taken to build spallation neutron sources whose time average neutron flux would reach to level of advanced high flux reactors now possible with highly enriched uranium as fuel material. Another uncertainty factor is the reliability and operational stability of an accelerator needed to achieve such a high power source, which also has never been built so far. Taking everything together, it must be stated that at the very minimum a substantial development effort in a number of fields would be required, most likely leading over various intermediate stages before spallation neutron sources can compete in flux level with advanced high flux reactor designs. (orig.)

  16. ITER relevant high heat flux testing on plasma facing surfaces

    International Nuclear Information System (INIS)

    The current ITER design employs beryllium, carbon fiber reinforced composite and tungsten as plasma facing materials. Since these materials are exposed to high heat fluxes during the operation, it is essential to perform high heat flux for R and D of ITER components. Static heat loads corresponding to cycling loads during normal operation, are estimated to be up to 20 MW/m2 in the divertor targets and around 0.5 MW/m2 at the first wall in ITER. For the static high heat flux testing, tests in electron beam facilities, particle beam facilities, IR heater and in-pile tests have been performed. Another type, more critical heat loads, which have high power densities and short durations, corresponding to transient events, i.e. plasma disruption, vertical displacement events (VDEs) and edge localized modes (ELMs) deliver considerable heat flux onto the plasma facing materials. For this purpose, tests in electron beam (short pulses), plasma gun and high power laser facilities have been carried out. The present work summarizes the features of these facilities and recent experimental results as well as the current selection of ITER plasma facing components. (author)

  17. High quality flux control system for electron gun evaporation

    International Nuclear Information System (INIS)

    This paper reports on a high quality flux control system for electron gun evaporation developed and tested for the MBE growth of high temperature superconductors. The system can be applied to any electron gun without altering the electron gun itself. Essential elements of the system are a high bandwidth mass spectrometer, control electronics and a high voltage modulator to sweep the electron beam over the melt at high frequencies. the sweep amplitude of the electron beam is used to control the evaporation flux at high frequencies. The feedback loop of the system has a bandwidth of over 100 Hz, which makes it possible to grow superlattices and layered structures in a fast and precisely controlled manner

  18. Brookhaven: Spin result underlined

    International Nuclear Information System (INIS)

    A recent experiment looking at violent proton-proton elastic scattering confirms, with high precision, earlier data which puzzled many theorists. Most pictures of strong interactions based on perturbative quark-gluon field theory (Quantum Chromodynamics, QCD) suggested that spin effects should disappear with energy and as the collisions become more violent

  19. High-flux, extended-pulse accelerators: Final report

    International Nuclear Information System (INIS)

    The purpose of the program was to investigate physical phenomena associated with high flux ion beam generation and to develop technology for intense ion beam accelerators with pulselengths in the ms range. At the time the work was initiated, the chief area of application for the technology was ion implantation and materials modification

  20. The dynamics of flux tubes in a high beta plasma

    CERN Document Server

    Vishniac, E T

    1994-01-01

    We suggest a new model for the structure of a magnetic field embedded high \\beta turbulent plasma, based on the popular notion that the magnetic field will tend to separate into individual flux tubes. We point out that interactions between the flux tubes will be dominated by coherent effects stemming from the turbulent wakes created as the fluid streams by the flux tubes. Balancing the attraction caused by shielding effects with turbulent diffusion we find that flux tubes have typical radii comparable to the local Mach number squared times the large scale eddy length, are arranged in a one dimensional fractal pattern, have a radius of curvature comparable to the largest scale eddies in the turbulence, and have an internal magnetic pressure comparable to the ambient pressure. When the average magnetic energy density is much less than the turbulent energy density the radius, internal magnetic field and curvature scale of the flux tubes will be smaller than these estimates. Realistic resistivity does not alter t...

  1. Plasma–Surface Interactions Under High Heat and Particle Fluxes

    Directory of Open Access Journals (Sweden)

    Gregory De Temmerman

    2013-01-01

    Full Text Available The plasma-surface interactions expected in the divertor of a future fusion reactor are characterized by extreme heat and particle fluxes interacting with the plasma-facing surfaces. Powerful linear plasma generators are used to reproduce the expected plasma conditions and allow plasma-surface interactions studies under those very harsh conditions. While the ion energies on the divertor surfaces of a fusion device are comparable to those used in various plasma-assited deposition and etching techniques, the ion (and energy fluxes are up to four orders of magnitude higher. This large upscale in particle flux maintains the surface under highly non-equilibrium conditions and bring new effects to light, some of which will be described in this paper.

  2. Brookhaven - going for gold

    International Nuclear Information System (INIS)

    Experiments using polarized (spin oriented) protons have a promising future at the Laboratory. Polarized sources are being improved considerably, and the advent of the Booster will enable accumulation of polarized beams before injection into the main ring. Adding these factors together indicates the possibility of colliding polarized proton beams in the proposed RHIC collider (of which more later) with a luminosity as high as 1032 and an energy of 350 GeV. The newcomer to the programme at the AGS is the series of experiments with light ion beams drawn from the nearby tandem. These began last October with oxygen-8 and silicon-14 beams at energies up to 15 GeV per nucleon and 5x108 accelerated ions per pulse for oxygen. (orig./HSI).

  3. Fabrication and high heat flux test of divertor cooling elements

    International Nuclear Information System (INIS)

    The plasma facing components in ITER are subjected to a high heat flux from fusion plasma. The heat flux is not only higher than that of existing tokamaks but also has a longer pulse duration (burn time). To minimize a peaking of the heat flux, the thermal deformation towards the plasma should be restrained. One-meter-long monoblock divertor modules with a sliding support structure were fabricated and tested at JAERI. Two kinds of support mechanisms were provided to minimize the thermal deformation of the modules in the upward and downward directions ; one is a pin type sliding structure and the other is a rail type support structure. Both modules were tested on the electron beam HHF test facility, JEBIS (JAERI Electron Beam Irradiation System), in JAERI. The steady-state heat flux of 15 MW/m2 was applied to the surface of the modules to simulate the design condition of ITER CDA. As a result of the HHF test, the performance of the sliding support structures was successfully demonstrated. Three dimensional elastic stress analyses were conducted using a finite element method. The result shows that the relatively high thermal stress is observed at the cooling tube ; and that the maximum thermal stress at the cooling tube exceeds its yield strength. It is necessary to perform the lifetime evaluation of the copper cooling tube against cyclic thermal stresses. (author)

  4. Generation of field-reversed-configurations with high bias flux using controlled reconnection

    International Nuclear Information System (INIS)

    The magnitude of poloidal flux and the ultimate size of field-reversed-configurations formed in field-reversed-theta-pinches depends on the amount of initial bias flux which can be trapped. Operation at high bias fluxes results in violent axial contractions and severe flux loss, thus preventing the attainment of high poloidal flux toroids. The use of controlled reconnection techniques permits stable generation at higher bias fluxes, and thus the generation of more energetic field-reversed-configurations

  5. Awareness, Preference, Utilization, and Messaging Research for the Spallation Neutron Source and High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    Oak Ridge National Laboratory (ORNL) offers the scientific community unique access to two types of world-class neutron sources at a single site - the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR). The 85-MW HFIR provides one of the highest steady-state neutron fluxes of any research reactor in the world, and the SNS is one of the world's most intense pulsed neutron beams. Management of these two resources is the responsibility of the Neutron Sciences Directorate (NScD). NScD commissioned this survey research to develop baseline information regarding awareness of and perceptions about neutron science. Specific areas of investigative interest include the following: (1) awareness levels among those in the scientific community about the two neutron sources that ORNL offers; (2) the level of understanding members of various scientific communities have regarding benefits that neutron scattering techniques offer; and (3) any perceptions that negatively impact utilization of the facilities. NScD leadership identified users of two light sources in North America - the Advanced Photon Source (APS) at Argonne National Laboratory and the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory - as key publics. Given the type of research in which these scientists engage, they would quite likely benefit from including the neutron techniques available at SNS and HFIR among their scientific investigation tools. The objective of the survey of users of APS, NSLS, SNS, and HFIR was to explore awareness of and perceptions regarding SNS and HFIR among those in selected scientific communities. Perceptions of SNS and FHIR will provide a foundation for strategic communication plan development and for developing key educational messages. The survey was conducted in two phases. The first phase included qualitative methods of (1) key stakeholder meetings; (2) online interviews with user administrators of APS and NSLS; and (3) one-on-one interviews

  6. Awareness, Preference, Utilization, and Messaging Research for the Spallation Neutron Source and High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Rebecca [Bryant Research, LLC; Kszos, Lynn A [ORNL

    2011-03-01

    Oak Ridge National Laboratory (ORNL) offers the scientific community unique access to two types of world-class neutron sources at a single site - the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR). The 85-MW HFIR provides one of the highest steady-state neutron fluxes of any research reactor in the world, and the SNS is one of the world's most intense pulsed neutron beams. Management of these two resources is the responsibility of the Neutron Sciences Directorate (NScD). NScD commissioned this survey research to develop baseline information regarding awareness of and perceptions about neutron science. Specific areas of investigative interest include the following: (1) awareness levels among those in the scientific community about the two neutron sources that ORNL offers; (2) the level of understanding members of various scientific communities have regarding benefits that neutron scattering techniques offer; and (3) any perceptions that negatively impact utilization of the facilities. NScD leadership identified users of two light sources in North America - the Advanced Photon Source (APS) at Argonne National Laboratory and the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory - as key publics. Given the type of research in which these scientists engage, they would quite likely benefit from including the neutron techniques available at SNS and HFIR among their scientific investigation tools. The objective of the survey of users of APS, NSLS, SNS, and HFIR was to explore awareness of and perceptions regarding SNS and HFIR among those in selected scientific communities. Perceptions of SNS and FHIR will provide a foundation for strategic communication plan development and for developing key educational messages. The survey was conducted in two phases. The first phase included qualitative methods of (1) key stakeholder meetings; (2) online interviews with user administrators of APS and NSLS; and (3) one

  7. RELAP5 model of the high flux isotope reactor with low enriched fuel thermal flux profiles

    Energy Technology Data Exchange (ETDEWEB)

    Banfield, J.; Mervin, B.; Hart, S.; Ritchie, J.; Walker, S.; Ruggles, A.; Maldonado, G. I. [Dept. of Nuclear Engineering, Univ. of Tennessee Knoxville, Knoxville, TN 37996-2300 (United States)

    2012-07-01

    The High Flux Isotope Reactor (HFIR) currently uses highly enriched uranium (HEU) fabricated into involute-shaped fuel plates. It is desired that HFIR be able to use low enriched uranium (LEU) fuel while preserving the current performance capability for its diverse missions in material irradiation studies, isotope production, and the use of neutron beam lines for basic research. Preliminary neutronics and depletion simulations of HFIR with LEU fuel have arrived to feasible fuel loadings that maintain the neutronics performance of the reactor. This article illustrates preliminary models developed for the analysis of the thermal-hydraulic characteristics of the LEU core to ensure safe operation of the reactor. The beginning of life (BOL) LEU thermal flux profile has been modeled in RELAP5 to facilitate steady state simulation of the core cooling, and of anticipated and unanticipated transients. Steady state results are presented to validate the new thermal power profile inputs. A power ramp, slow depressurization at the outlet, and flow coast down transients are also evaluated. (authors)

  8. Variability of methane fluxes over high latitude permafrost wetlands

    OpenAIRE

    Andrei Serafimovich; Hartmann, J.; Eric Larmanou; Torsten Sachs

    2013-01-01

    Atmospheric methane plays an important role in the global climate system. Due to significant amounts of organic material stored in the upper layers of high latitude permafrost wetlands and a strong Arctic warming trend, there is concern about potentially large methane emissions from Arctic and sub-Arctic areas. The quantification of methane fluxes and their variability from these regions therefore plays an important role in understanding the Arctic carbon cycle and changes in atmo...

  9. High Tc Superconductor Theoretical Models and Electromagnetic Flux Characteristics

    Institute of Scientific and Technical Information of China (English)

    JIN Jian-xun

    2006-01-01

    High Tc Superconductors (HTS) have special electromagnetic characteristics and phenomena. Effort has been made in order to theoretically understand the applied HTS superconductivity and HTS behaviors for practical applications, various theoretical models related to the HTS electromagnetic properties have been developed. The theoretical models and analytic methods are summarized with regard to understanding the HTS magnetic flux characteristic which is one of the most critical issues related to HTS applications such as for HTS magnetic levitation application.

  10. Annual progress report 1988, operation of the high flux reactor

    International Nuclear Information System (INIS)

    In 1988 the High Flux Reactor Petten was routinely operated without any unforeseen event. The availability was 99% of scheduled operation. Utilization of the irradiation positions amounted to 80% of the practical occupation limit. The exploitation pattern comprised nuclear energy deployment, fundamental research with neutrons, and radioisotope production. General activities in support of running irradiation programmes progressed in the normal way. Development activities addressed upgrading of irradiation devices, neutron radiography and neutron capture therapy

  11. Brookhaven highlights, October 1978-September 1979. [October 1978 to September 1979

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    These highlights present an overview of the major research and development achievements at Brookhaven National Laboratory from October 1978 to September 1979. Specific areas covered include: accelerator and high energy physics programs; high energy physics research; the AGS and improvements to the AGS; neutral beam development; heavy ion fusion; superconducting power cables; ISABELLE storage rings; the BNL Tandem accelerator; heavy ion experiments at the Tandem; the High Flux Beam Reactor; medium energy physics; nuclear theory; atomic and applied physics; solid state physics; neutron scattering studies; x-ray scattering studies; solid state theory; defects and disorder in solids; surface physics; the National Synchrotron Light Source ; Chemistry Department; Biology Department; Medical Department; energy sciences; environmental sciences; energy technology programs; National Center for Analysis of Energy Systems; advanced reactor systems; nuclear safety; National Nuclear Data Center; nuclear materials safeguards; Applied Mathematics Department; and support activities. (GHT)

  12. Applicability of copper alloys for DEMO high heat flux components

    Science.gov (United States)

    Zinkle, Steven J.

    2016-02-01

    The current state of knowledge of the mechanical and thermal properties of high-strength, high conductivity Cu alloys relevant for fusion energy high heat flux applications is reviewed, including effects of thermomechanical and joining processes and neutron irradiation on precipitation- or dispersion-strengthened CuCrZr, Cu-Al2O3, CuNiBe, CuNiSiCr and CuCrNb (GRCop-84). The prospects for designing improved versions of wrought copper alloys and for utilizing advanced fabrication processes such as additive manufacturing based on electron beam and laser consolidation methods are discussed. The importance of developing improved structural materials design criteria is also noted.

  13. Design Analysis of High-Speed Axial-Flux Generator

    Directory of Open Access Journals (Sweden)

    M. Sadeghierad

    2008-01-01

    Full Text Available Problem Statement: Axial flux permanent magnet machines are regarded as compact high efficiency generators for micro-turbines employed in the distributed power generation systems. High-speed rotor of the generator causes some designing and modeling problems. Sensitivity analysis tasks of the machine parameters are difficult and completely different in comparison with the problems associated with conventional machines. Approach: This article presents a modeling procedure with some details for performance predictions of High-Speed Axial Flux Generator (HSAFG. The FEM results are employed to validate the proposed model. Proper values of inner diameter to outer diameter ratio, plus back iron thickness of two rotor discs located in two ends are serious design problem for a HSAFG. Results: Impacts of these two parameters on the performance characteristics of a HSAFG are investigated in this paper. Their optimum values are determined for the machine by somewhat precise considerations of the output voltage and efficiency. Conclusions/Recommendations: It has been found out that the optimum performance of HSAFG regarding the voltage and efficiency is achieved by the value of inner to outer diameter ratio sited between 0.5-0.65. Moreover, the thickness of the rotor back iron can be designed by trial method to produce sufficient air gap flux and resultant terminal voltage. Adding extra back iron would just increase the rotor inertia with no benefit.

  14. High Flux Metallic Membranes for Hydrogen Recovery and Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Buxbaum, Robert

    2010-06-30

    We made and tested over 250 new alloys for use as lower cost, higher flux hydrogen extraction membrane materials. Most of these were intermetallic, or contained significant intermetallic content, particularly based on B2 alloy compositions with at least one refractory component; B2 intermetallics resemble BCC alloys, in structure, but the atoms have relatively fixed positions, with one atom at the corners of the cube, the other at the centers. The target materals we were looking for would contain little or no expensive elements, no strongly toxic or radioactive elements, would have high flux to hydrogen, while being fabricable, brazable, and relatively immune to hydrogen embrittlement and corrosion in operation. The best combination of properties of the membrane materials we developed was, in my opinion, a Pd-coated membrane consisting of V -9 atomic % Pd. This material was relatively cheap, had 5 times the flux of Pd under the same pressure differential, was reasonably easy to fabricate and braze, and not bad in terms of embrittlement. Based on all these factors we project, about 1/3 the cost of Pd, on an area basis for a membrane designed to last 20 years, or 1/15 the cost on a flux basis. Alternatives to this membrane replaced significant fractions of the Pd with Ni and or Co. The cost for these membranes was lower, but so was the flux. We produced successful brazed products from the membrane materials, and made them into flat sheets. We tested, unsuccessfully, several means of fabricating thematerials into tubes, and eventually built a membrane reactor using a new, flat-plate design: a disc and doughnut arrangement, a design that seems well- suited to clean hydrogen production from coal. The membranes and reactor were tested successfully at Western Research. A larger equipment company (Chart Industries) produced similar results using a different flat-plate reactor design. Cost projections of the membrane are shown to be attractive.

  15. Status of the IDTF high-heat-flux test facility

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, V.; Gorbenko, A.; Davydov, V.; Kokoulin, A.; Komarov, A.; Mazul, I.; Mudyugin, B.; Ovchinnikov, I.; Stepanov, N.; Rulev, R.; Volodin, A., E-mail: volodin@sintez.niiefa.spb.su

    2014-10-15

    Highlights: • In the Efremov Institute the IDTF (ITER Divertor Test Facility) was created for the high heat flux tests (HHFT) of the PFUs of the ITER divertor. • In summer 2012, the IDTF had been qualified for the testing of the outer vertical full-scale prototypes. • The HHFT of the test assembly of the outer vertical target full-scale prototype – was completed at the end of 2012. - Abstract: The ITER Divertor Test Facility (IDTF) was designed for the high heat flux tests of outer vertical targets, inner vertical targets and domes of the ITER divertor. This facility was created in the Efremov Institute under the Procurement Arrangement 1.7.P2D.RF (high heat flux tests of the plasma facing units of the ITER divertor). The heat flux is generated by an electron-beam system (EBS), 800 kW power and 60 kV maximum accelerating voltage. The component to be tested is mounted on a manipulator in the vacuum chamber capable of testing objects up to 2.5 m long and 1.5 m wide. The pressure in the vacuum chamber is about 3*10{sup −3} Pa. The parameters of the cooling system and the water quality (deionized water) are similar to the cooling conditions of the ITER divertor. The integrated control system regulates all IDTF subsystems and data acquisition from all diagnostic devices, such as pyrometers, IR-cameras, video cameras, flow, pressure and temperature sensors. Started in 2008, the IDTF was commissioned in 2012 with the testing the outer vertical full-scale prototypes and the completion of the PA 1.7.P2D.RF task. This paper details the main characteristics of the IDTF.

  16. High Energy Atmospheric Neutrino Fluxes From a Realistic Primary Spectrum

    Science.gov (United States)

    Campos Penha, Felipe; Dembinski, Hans; Gaisser, Thomas K.; Tilav, Serap

    2016-03-01

    Atmospheric neutrino fluxes depend on the energy spectrum of primary nucleons entering the top of the atmosphere. Before the advent of AMANDA and the IceCube Neutrino Observatory, measurements of the neutrino fluxes were generally below ~ 1TeV , a regime in which a simple energy power law sufficed to describe the primary spectrum. Now, IceCube's muon neutrino data extends beyond 1PeV , including a combination of neutrinos from astrophysical sources with background from atmospheric neutrinos. At such high energies, the steepening at the knee of the primary spectrum must be accounted for. Here, we describe a semi-analytical approach for calculating the atmospheric differential neutrino fluxes at high energies. The input is a realistic primary spectrum consisting of 4 populations with distinct energy cutoffs, each with up to 7 representative nuclei, where the parameters were extracted from a global fit. We show the effect of each component on the atmospheric neutrino spectra, above 10TeV . The resulting features follow directly from recent air shower measurements included in the fit. Felipe Campos Penha gratefully acknowledges financial support from CAPES (Processo BEX 5348/14-5), CNPq (Processo 142180/2012-2), and the Bartol Research Institute.

  17. High flux lithium antineutrino source with variable hard spectrum

    CERN Document Server

    Lyashuk, V I

    2016-01-01

    The high flux antineutrino source with hard antineutrino spectrum based on neutron activation of 7Li and subsequent fast beta-decay (T 1/2 = 0.84 s) of the 8Li isotope with emission of antineutrino with energy up to 13 MeV - is discussed. Creation of the intensive isotope neutrino source of hard spectrum will allow to increase the detection statistics of neutrino interaction and it is especially urgent for oscillation experiments. The scheme of the proposed neutrino source is based on the continuous transport of the created 8Li to the neutrino detector, which moved away from the place of neutron activation. Analytical expressions for lithium antineutrino flux is obtained. The discussed source will ensure to increase the cross section for reactions with deuteron from several times to tens compare to the reactor antineutrino spectrum. An another unique feature of the installation is the possibility to vary smoothly the hardness of the antineutrino spectrum.

  18. High neutron flux quality for irradiation and BCNT conditions

    International Nuclear Information System (INIS)

    This paper presents methods for characterising the neutron field in irradiation and boron neutron capture therapy (BNCT) facilities, applications for which a high flux quality is needed. The irradiation facility considered consists of an isotopic (Am-Be) neutron source in a cylindrical cavity bored inside a solid paraffin cube measuring 51·51·51 cm, thus constituting a neutron Howitzer. The neutron flux distribution within the cavity above this source was investigated by measurements of aluminium foil activation and by calculations with the MCNP-4C code. The BNCT calculations were performed for different channel radii. Results from measurements and calculations are in good agreement despite the uncertainties in identifying the exact energies at which the two reactions measured, 27Al(n,γ)28Al and 27Al(n, p)27Mg, take place. The study provided useful information about the optimal irradiation and BNCT conditions. (author)

  19. Brookhaven highlights. [Fiscal year 1992, October 1, 1991--September 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.S.; Cohen, A.; Greenberg, D.; Seubert, L. [eds.

    1992-12-31

    This publication provides a broad overview of the research programs and efforts being conducted, built, designed, and planned at Brookhaven National Laboratory. This work covers a broad range of scientific disciplines. Major facilities include the Alternating Gradient Synchrotron (AGS), with its newly completed booster, the National Synchrotron Light Source (NSLS), the High Flux Beam Reactor (HFBR), and the RHIC, which is under construction. Departments within the laboratory include the AGS department, accelerator development, physics, chemistry, biology, NSLS, medical, nuclear energy, and interdepartmental research efforts. Research ranges from the pure sciences, in nuclear physics and high energy physics as one example, to environmental work in applied science to study climatic effects, from efforts in biology which are a component of the human genome project to the study, production, and characterization of new materials. The paper provides an overview of the laboratory operations during 1992, including staffing, research, honors, funding, and general laboratory plans for the future.

  20. Resistance, flux motion and pinning in high temperature superconductors

    International Nuclear Information System (INIS)

    Properties of a vortex systems in high-temperature superconductors are now under intense investigation. As observed by Muller et al. and Yeshurun and Malozemoff, the relaxation of magnetization supposes that flux creep plays an important role in magnetic measurements. The experiments by Palstra et al. clearly demonstrate the thermally activated nature of resistivity in a wide region below Tc. The activation energy depends on the magnetic field, the temperature, and the transport current. The current dependence of the activation energy is a very remarkable feature of a vortex state. If in the limit of small current the activation energy tends to infinity (flux creep), it can be considered a true superconducting state with zero ohmic resistivity. If the small current limit of the activation energy is finite, then ohmic resistivity exists and this region is called thermally assisted flux flow (TAFF). The transition between ohmic and non-ohmic resistivity was observed by Koch et al. Experiments by Yeshurun and Malozemoff, Palstra et al., Kim et al., and Brunner et al. give different magnetic field dependence of the activation energy. The theoretical study of the activation processes in a liquid state and the estimation of the activation energy as a function of the magnetic field and temperature are not a simple problem. Some approaches for the liquid state are here

  1. Flux flow in high-Tc Josephson junctions

    DEFF Research Database (Denmark)

    Filatrella, G.; Pedersen, Niels Falsig

    1993-01-01

    The possibility of achieving fluxon nucleation in nonhysteretic high-T(c) Josephson junctions due to the presence of inhomogeneities is investigated numerically. For a large range of parameters the I- V characteristics in presence of such discontinuities show a strong similarity with those obtained...... experimentally. The spatial inhomogeneities considered are on the scale of the Josephson penetration depth (mum). It is demonstrated that the topic is of interest for the construction of amplifiers. Thus when fluxons are generated the resulting flux flow regime proves to be much more sensitive than the uniform...

  2. Neutron scattering from the flux lattice in high temperature superconductors

    International Nuclear Information System (INIS)

    Neutron scattering has been used to observe diffraction from the flux-line lattice in high temperature superconductors. This technique is particularly useful in such systems as it allows observations to be made over a wide range of temperature and magnetic field. Experiments on the systems K0.4Ba0.6BiO3 and YBa2Cu3O7--8 will be described with applied magnetic fields of up to 4 Tesla and for temperatures from 2K to Tc

  3. Annual Report 1991. Operation of the high flux reactor

    International Nuclear Information System (INIS)

    In 1991 the operation of the High Flux Reactor was carried out as planned. The availability was more than 100% of scheduled operating time. The average utilization of the reactor was 69% of the practical limit. The reactor was utilized for research programmes in support of nuclear fission reactors and thermonuclear fusion, for fundamental research with neutrons, for radioisotope production, and for various smaller activities. Development activities addressed upgrading of irradiation devices, neutron capture therapy, neutron radiography and neutron transmutation doping of silicon. General activities in support of running irradiation programmes progressed in the normal way

  4. Annual report 1989 operation of the high flux reactor

    International Nuclear Information System (INIS)

    In 1989 the operation of the High Flux Reactor Petten was carried out as planned. The availability was more than 100% of scheduled operating time. The average occupation of the reactor by experimental devices was 72% of the practical occupation limit. The reactor was utilized for research programmes in support of nuclear fission reactors and thermonuclear fusion, for fundamental research with neutrons and for radioisotope production. General activities in support of running irradiation programmes progressed in the normal way. Development activities addressed upgrading of irradiation devices, neutron radiography and neutron capture therapy

  5. Enzymatically active high-flux selectively gas-permeable membranes

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Ying-Bing; Cecchi, Joseph L.; Rempe, Susan; FU, Yaqin; Brinker, C. Jeffrey

    2016-01-26

    An ultra-thin, catalyzed liquid transport medium-based membrane structure fabricated with a porous supporting substrate may be used for separating an object species such as a carbon dioxide object species. Carbon dioxide flux through this membrane structures may be several orders of magnitude higher than traditional polymer membranes with a high selectivity to carbon dioxide. Other gases such as molecular oxygen, molecular hydrogen, and other species including non-gaseous species, for example ionic materials, may be separated using variations to the membrane discussed.

  6. Annual report 1990. Operation of the high flux reactor

    International Nuclear Information System (INIS)

    In 1990 the operation of the High Flux Reactor was carried out as planned. The availability was 96% of scheduled operating time. The average utilization of the reactor was 71% of the practical limit. The reactor was utilized for research programmes in support of nuclear fission reactors and thermonuclear fusion, for fundamental research with neutrons, for radioisotope production, and for various smaller activities. General activities in support of running irradiation programmes progressed in the normal way. Development activities addressed upgrading of irradiation devices, neutron radiography and neutron capture therapy

  7. High-flux solar photon processes: Opportunities for applications

    Energy Technology Data Exchange (ETDEWEB)

    Steinfeld, J I; Coy, S L; Herzog, H; Shorter, J A; Schlamp, M; Tester, J W; Peters, W A [Massachusetts Inst. of Tech., Cambridge, MA (United States)

    1992-06-01

    The overall goal of this study was to identify new high-flux solar photon (HFSP) processes that show promise of being feasible and in the national interest. Electric power generation and hazardous waste destruction were excluded from this study at sponsor request. Our overall conclusion is that there is promise for new applications of concentrated solar photons, especially in certain aspects of materials processing and premium materials synthesis. Evaluation of the full potential of these and other possible applications, including opportunities for commercialization, requires further research and testing. 100 refs.

  8. BVOC ecosystem flux measurements at a high latitude wetland site

    Directory of Open Access Journals (Sweden)

    T. Holst

    2008-12-01

    Full Text Available In this study, we present summertime concentrations and fluxes of biogenic volatile organic compounds (BVOCs measured at a sub-arctic wetland in northern Sweden using a disjunct eddy-covariance (DEC technique based on a proton transfer reaction mass spectrometer (PTR-MS. The vegetation at the site was dominated by Sphagnum, Carex and Eriophorum spp. The performance of the DEC system was assessed by comparing H3O+-ion cluster formed with water molecules (H3O+(H2O at m37 with water vapour concentration measurements made using an adjacent humidity sensor, and from a comparison of sensible heat fluxes for high frequency and DEC data obtained from the sonic anemometer. These analyses showed no significant PTR-MS sensor drift over a period of several weeks and only a small flux-loss due to high-frequency spectrum omissions. This loss was within the range expected from other studies and the theoretical considerations.

    Standardised (20°C and 1000 μmol m−2 s−1 PAR summer isoprene emission rates of 323 μg C m−2 (ground area h−1 were comparable with findings from more southern boreal forests, and fen-like ecosystems. On a diel scale, measured fluxes indicated a stronger temperature dependence when compared with emissions from temperate or (subtropical ecosystems. For the first time, to our knowledge, we report ecosystem methanol fluxes from a sub-arctic ecosystem. Maximum daytime emission fluxes were around 270 μg m−2 h−1 (ca. 100 μg C m−2 h-1 and measurements indicated some nocturnal deposition.

    The measurements reported here covered a period of 50 days (1 August to 19 September 2006, approximately one half of the growing season at the site, and allowed to investigate the effect of vegetation senescence on daily BVOC fluxes and on their temperature and light

  9. High flux transmutation of fission products and actinides

    International Nuclear Information System (INIS)

    Long-lived fission products and minor actinides accumulated in spent nuclear fuel of power reactors comprise the major part of high level radwaste. Their incineration is important from the point of view of radwaste management. Transmutation of these nuclides by means of neutron irradiation can be performed either in conventional nuclear reactors, or in specialized transmutation reactors, or in ADS facilities with subcritical reactor and neutron source with application of proton accelerator. Different types of transmutation nuclear facilities can be used in order to insure optimal incineration conditions for radwaste. The choice of facility type for optimal transmutation should be based on the fundamental data in the physics of nuclide transformations. Transmutation of minor actinides leads to the increase of radiotoxicity during irradiation. It takes significant time compared to the lifetime of reactor facility to achieve equilibrium without effective transmutation. High flux nuclear facilities allow to minimize these draw-backs of conventional facilities with both thermal and fast neutron spectrum. They provide fast approach to equilibrium and low level of equilibrium mass and radiotoxicity of transmuted actinides. High flux facilities are advantageous also for transmutation of long-lived fission products as they provide short incineration time

  10. Blistering on tungsten surface exposed to high flux deuterium plasma

    Science.gov (United States)

    Xu, H. Y.; Liu, W.; Luo, G. N.; Yuan, Y.; Jia, Y. Z.; Fu, B. Q.; De Temmerman, G.

    2016-04-01

    The blistering behaviour of tungsten surfaces exposed to very high fluxes (1-2 × 1024/m2/s) of low energy (38 eV) deuterium plasmas was investigated as a function of ion fluence (0.2-7 × 1026 D/m2) and surface temperature (423-873 K). Blisters were observed under all conditions, especially up to temperatures of 873 K. The blister parameters are evaluated with blister size, blister density and surface coverage. The blister size always peaked at less than 0.5 μm and no blister larger than 10 μm is observed even at high fluence. The blister densities are found in high magnitude of 106 blisters/m2, with the surface coverages lower than 2%. The formation of cracks in the sub-surface region was observed by cross-section imaging. Changes in blister size and shape with fluence and temperature suggest processes of predominantly nucleation and subsequent growth of blisters. The smaller blister size is considered to be caused by a combination of flux-related effects such as enhanced defect formation in the near surface region, reduced deuterium diffusivity and relatively short exposure times.

  11. Neutronics modeling of the High Flux Isotope Reactor using COMSOL

    International Nuclear Information System (INIS)

    Highlights: → Neutron flux distributions in HFIR were calculated with SCALE v6 and COMSOL v3.5. → Diffusion theory employed in COMSOL coefficient partial differential equation mode. → Two-group 2D flux distributions compare well to benchmarked 3D stochastic models. → Adaptive mesh refinement algorithm used to refine mesh and improve accuracy. → First step in a long-term project to upgrade research reactor analytical methods. - Abstract: The High Flux Isotope Reactor located at the Oak Ridge National Laboratory is a versatile 85 MWth research reactor with cold and thermal neutron scattering, materials irradiation, isotope production, and neutron activation analysis capabilities. HFIR staff members are currently in the process of updating the thermal hydraulic and reactor transient modeling methodologies. COMSOL Multiphysics has been adopted for the thermal hydraulic analyses and has proven to be a powerful finite-element-based simulation tool for solving multiple physics-based systems of partial and ordinary differential equations. Modeling reactor transients is a challenging task because of the coupling of neutronics, heat transfer, and hydrodynamics. This paper presents a preliminary COMSOL-based neutronics study performed by creating a two-dimensional, two-group, diffusion neutronics model of HFIR to study the spatially-dependent, beginning-of-cycle fast and thermal neutron fluxes. The 238-group ENDF/B-VII neutron cross section library and NEWT, a two-dimensional, discrete-ordinates neutron transport code within the SCALE 6 code package, were used to calculate the two-group neutron cross sections required to solve the diffusion equations. The two-group diffusion equations were implemented in the COMSOL coefficient form PDE application mode and were solved via eigenvalue analysis using a direct (PARDISO) linear system solver. A COMSOL-provided adaptive mesh refinement algorithm was used to increase the number of elements in areas of largest numerical

  12. Development of a High Flux Research Reactor with Assembly- Integral Flux Traps

    International Nuclear Information System (INIS)

    In recent years, the demand for irradiation services has increased as research reactors face a number of challenges. These challenges include reduction in enrichment, the need for economical use of fuel, and the medical isotope crisis brought about by the temporary shutdowns of the NRU and HFR. These challenges have inspired the design of a revolutionary research reactor assembly concept making use of the new U-Mo monolithic fuel form. Each assembly consists of a trapezoidal plate-fueled region and integral triangular flux trap. When placed in a hexagonal core, this structure permits multiple orientations of the flux trap with respect to those surrounding it. As a result, multiple orientations, sizes and shapes of the flux trap are possible. These flux trap parameters can be adjusted to provide the spectra needed to meet ever-changing experimental needs. This assembly concept was applied to the development of a 5 MWth research reactor core, and optimized for peak thermal flux. During the design process, attention was given to making the design economical, manufacturable, and maintainable. The design was able to produce a maximum unperturbed thermal flux of 1.2 x 1014 neutrons/cm2 s, 70% higher than existing research reactors of the same power rating. Despite this optimization for thermal flux, the reactor is still capable of producing fast fluxes in excess of 1 x 1014 neutrons/cm2 s in other regions of the core. The response of the resulting core to thermal hydraulic transients was also analyzed. (author)

  13. Scientists at Brookhaven contribute to the development of a better electron accelerator

    CERN Multimedia

    2004-01-01

    Scientists working at Brookhaven have developed a compact linear accelerator called STELLA (Staged Electron Laser Acceleration). Highly efficient, it may help electron accelerators become practical tools for applications in industry and medicine, such as radiation therapy (1 page)

  14. Advanced Tethersonde for High-Speed Flux Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Flux measurements of trace gases and other quantities, such as latent heat, are of great importance in scientific field research. One typical flux measurement setup...

  15. Design of a high-gain flux-compression generator

    International Nuclear Information System (INIS)

    The current gain of a high-gain, high-explosive helical magnetic-flux-compression generator (HEG) is limited both by nonuniformities in stator expansion and by armature-stator misalignment. The authors report on their work to achieve three goals: first, an output current of at least 2 MA with a current gain greater than 1000 to drive a 150-to 300-nH load; second, a generator with an acceptably small volume and length; and finally, generator output of a reliable magnitude. To achieve these performance goals, the authors had to pay careful attention to design aspects of mechanical tolerances. They increased the diameter of the armature winding wire to limit the action integral at a given location along it to a value below the surface melting point

  16. Fuel management at the Petten high flux reactor

    International Nuclear Information System (INIS)

    Several years ago the shipment of spent fuel of the High Flux Reactor (HFR) at Petten has come to a standstill resulting in an ever growing stock of fuel elements that are labelled 'fully burnt up'. Examination of those elements showed that a reasonably number of them have a relatively high 235U mass left. A reactor physics analysis showed that the use of such elements in the peripheral core zone allows the loading of four instead of five fresh fuel elements in many cycle cores. For the assessment of safety and performance parameters of HFR cores a new calculational tool is being developed. It is based on AEA Technology's Reactor physics code suite Winfrith Improved Multigroup Scheme (WIMS). NRG produced pre- and post-processing facilities to feed input data into WIMS's 2D transport code CACTUS and to extract relevant parameters from the output. The processing facilities can be used for many different types of application. (author)

  17. BROOKHAVEN NATIONAL LABORATORY WILDLIFE MANAGEMENT PLAN.

    Energy Technology Data Exchange (ETDEWEB)

    NAIDU,J.R.

    2002-10-22

    The purpose of the Wildlife Management Plan (WMP) is to promote stewardship of the natural resources found at the Brookhaven National Laboratory (BNL), and to integrate their protection with pursuit of the Laboratory's mission.

  18. Dialyzer Reuse and Outcomes of High Flux Dialysis.

    Directory of Open Access Journals (Sweden)

    Christos Argyropoulos

    Full Text Available The bulk of randomized trial evidence for the expanding use of High Flux (HF hemodialysis worldwide comes from two randomized controlled trials, one of which (HEMODIALYSIS, HEMO allowed, while the other (Membrane Outcomes Permeability, MPO excluded, the reuse of membranes. It is not known whether dialyzer reuse has a differential impact on outcomes with HF vs low flyx (LF dialyzers.Proportional Hazards Models and Joint Models for longitudinal measures and survival outcomes were used in HEMO to analyze the relationship between β2-microglobulin (β2M concentration, flux, and reuse. Meta-analysis and regression techniques were used to synthesize the evidence for HF dialysis from HEMO and MPO.In HEMO, minimally reused (< 6 times HF dialyzers were associated with a hazard ratio (HR of 0.67 (95% confidence interval, 95%CI: 0.48-0.92, p = 0.015, 0.64 (95%CI: 0.44 - 0.95, p = 0.03, 0.61 (95%CI: 0.41 - 0.90, p = 0.012, 0.53 (95%CI: 0.28 - 1.02, p = 0.057 relative to minimally reused LF ones for all cause, cardiovascular, cardiac and infectious mortality respectively. These relationships reversed for extensively reused membranes (p for interaction between reuse and flux < 0.001, p = 0.005 for death from all cause and cardiovascular causes, while similar trends were noted for cardiac and infectious mortality (p of interaction between reuse and flux of 0.10 and 0.08 respectively. Reduction of β2M explained only 1/3 of the effect of minimally reused HF dialyzers on all cause mortality, while non-β2M related factors explained the apparent attenuation of the benefit with more extensively reused dialyzers. Meta-regression of HEMO and MPO estimated an adjusted HR of 0.63 (95% CI: 0.51-0.78 for non-reused HF dialyzers compared with non-reused LF membranes.This secondary analysis and synthesis of two large hemodialysis trials supports the widespread use of HF dialyzers in clinical hemodialysis over the last decade. A mechanistic understanding of the effects of

  19. Flux Creep and Giant Flux Creep in High Tc Hg,Pb-based Superconductors

    Science.gov (United States)

    Kirven, Douglas; Owens, Frank; Iqbal, Z.; Bleiweiss, M.; Lungu, A.; Datta, T.

    1996-03-01

    Dynamic behavior of the trapped flux in fields of up to 17.5 T was studied in a set of Hg-Pb based superconductors with a Tc in excess of 130 K. Depending on the experimental conditions, both creep and giant flux creep dynamics were observed. Results were analyzed using to standard models such as Anderson-Kim and giant-flux creep models (GFC). The plots of relaxation rate of remnant magnetization versus temperature show a peak below Tc. These results were compared with other Cu-O compounds. A distribution of activation energies was found from the magnetization rate. The activation energy distribution shows a peak around 50 K. The peak determines the temperature where the flux flow rate is a maximum. A universal relation of the resistive behavior was also found as a function of temperature and field. The zero-field/field-cooled results gave a reversibility curve that also obeyed a universal power relation.

  20. ATLAS Overview Week at Brookhaven

    CERN Multimedia

    Pilcher, J

    Over 200 ATLAS participants gathered at Brookhaven National Laboratory during the first week of June for our annual overview week. Some system communities arrived early and held meetings on Saturday and Sunday, and the detector interface group (DIG) and Technical Coordination also took advantage of the time to discuss issues of interest for all detector systems. Sunday was also marked by a workshop on the possibilities for heavy ion physics with ATLAS. Beginning on Monday, and for the rest of the week, sessions were held in common in the well equipped Berkner Hall auditorium complex. Laptop computers became the norm for presentations and a wireless network kept laptop owners well connected. Most lunches and dinners were held on the lawn outside Berkner Hall. The weather was very cooperative and it was an extremely pleasant setting. This picture shows most of the participants from a view on the roof of Berkner Hall. Technical Coordination and Integration issues started the reports on Monday and became a...

  1. Flux pinning and flux dynamics in (Tl/Pb)-(Sr/Ba)-Ca-Cu-O high temperature superconductors

    International Nuclear Information System (INIS)

    The following topics were dealt with: The structure of Tl-high temperature superconductors, flux line dynamics in HTSCs, the preparation of Tl-1223 and Tl-2223 (polycrystalline and single crystals), experimental characterization using microstructure and phase studies, magnetic susceptibility, magnetisation and relaxation measurements, transport current and resistance measurements, experimental results on flux creep including relaxation of the irreversible magnetisation for long and short times

  2. Developing a High-Flux Isolated Attosecond Pulse Source

    Science.gov (United States)

    Kamalov, Andrei; Ware, Matthew; Bucksbaum, Philip; Cryan, James

    2016-05-01

    High harmonic based light sources have proven to be valuable experimental tools that facilitate studies of electron dynamics at their natural timescale, the attosecond regime. The nature of driving laser sources used in high harmonic generation make it difficult to attain attosecond pulses that are both isolated in time and of a high intensity. We present our progress in commissioning a beamline designed to produce high-flux isolated attosecond pulses. A multistep amplification process provides us with 30 mJ, 25 fs pulses centered around 800 nm with 100 Hz repetition rate. These pulses are spatially split and focused into a gas cell. A non-collinear optical gating scheme is used to produce a lighthouse source of high harmonic radiation wherein each beamlet is an isolated attosecond pulse. A variable-depth grazing-incidence stepped mirror is fabricated to extend the optical path length of the older beamlets and thus overlap the beamlets in time. The combined beam is tightly focused and ensuing mechanics will be studied with an electron spectrometer as well as a xuv photon spectrometer. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division.

  3. Surveillance programme and upgrading of the High Flux Reactor Petten

    International Nuclear Information System (INIS)

    The High Flux Reactor (HFR) at Petten (The Netherlands), a 45 MW light water cooled and moderated research reactor in operation during more than 30 years, has been kept up to date by replacing ageing components. In 1984, the HFR was shut down for replacement of the aluminium. reactor vessel which had been irradiated during more than 20 years. The demonstration that the new vessel contains no critical defect requires knowledge of the material properties of the aluminium alloy Al 5154 with and without neutron irradiation and of the likely defect presence through the periodic in-service inspections. An irradiation damage surveillance programme has been started in 1985 for the new vessel material to provide information on fracture mechanics properties. After the vessel replacement, the existing process of continuous upgrading and replacement of ageing components was accelerated. A stepwise upgrade of the control room is presently under realization. (author)

  4. Neutron diffraction facilities at the high flux reactor, Petten

    Science.gov (United States)

    Ohms, C.; Youtsos, A. G.; Bontenbal, A.; Mulder, F. M.

    2000-03-01

    The High Flux Reactor in Petten is equipped with twelve beam tubes for the extraction of thermal neutrons for applications in materials and medical science. Beam tubes HB4 and HB5 are equipped with diffractometers for residual stress and powder investigations. Recently at HB4 the Large Component Neutron Diffraction Facility has been installed. It is a unique facility with respect to its capability of handling heavy components up to 1000 kg in residual stress testing. Its basic features are described and the first applications on thick piping welds are shown. The diffractometer at HB5 can be set up for powder and stress measurements. Recent applications include temperature dependent measurements on phase transitions in intermetallic compounds and on Li ion energy storage materials.

  5. Experience with high heat flux components in large tokamaks

    International Nuclear Information System (INIS)

    The large present day tokamaks. i.e.JET, TFTR, JT-60, DIII-D and Tore Supra are machines capable of sustaining plasma currents of several million amperes. Pulse durations range from a few seconds up to a minute. These large machines have been in operation for several years and there exists wide experience with materials for plasma facing components. Bare and coated metals, bare and coated graphites and beryllium were used for walls, limiters and divertors. High heat flux components are mainly radiation cooled, but stationary cooling for long pulse duration is also employed. This paper summarizes the experience gained in the large machines with respect to material selection, component design, problem areas, and plasma performance. 2 tabs., 26 figs., 50 refs

  6. Mechanism of a high-Tc superconducting flux pump: Using alternating magnetic field to trigger flux flow

    Science.gov (United States)

    Geng, Jianzhao; Coombs, T. A.

    2015-10-01

    High-Tc Superconducting (HTS) magnets operating in persistent current mode suffer a current decay due to flux creep of superconductor and joint resistance. Flux pumps are able to inject direct current into superconducting circuit to compensate the current decay, without the thermal loss caused by current leads. In this work, we proposed a flux pumping mechanism for HTS coils, with an experimental verification and an analytical model. The basic principle we have used is that flux flow can be triggered when the superconductor carrying a direct current is subjected to a perpendicular AC magnetic field. Low frequency alternating current is induced in a loop of YBCO tape using an AC field. A portion of the tape which we refer to as the "bridge" shorts a superconducting coil. A high frequency AC field is applied perpendicular to the bridge tape when alternating current in the tape reaches one polarity. This triggers a net flux flow and results in a current increase in the coil. The proposed flux pump has clear physics and is easily controllable, which may make it promising in practical use.

  7. Flux transformers made of commercial high critical temperature superconducting wires.

    Science.gov (United States)

    Dyvorne, H; Scola, J; Fermon, C; Jacquinot, J F; Pannetier-Lecoeur, M

    2008-02-01

    We have designed flux transformers made of commercial BiSCCO tapes closed by soldering with normal metal. The magnetic field transfer function of the flux transformer was calculated as a function of the resistance of the soldered contacts. The performances of different kinds of wires were investigated for signal delocalization and gradiometry. We also estimated the noise introduced by the resistance and showed that the flux transformer can be used efficiently for weak magnetic field detection down to 1 Hz. PMID:18315329

  8. High Flux Isotope Reactor cold neutron source reference design concept

    International Nuclear Information System (INIS)

    In February 1995, Oak Ridge National Laboratory's (ORNL's) deputy director formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. In May 1995, a team was formed to examine the feasibility of retrofitting a liquid hydrogen (LH2) cold source facility into an existing HFIR beam tube. The results of this feasibility study indicated that the most practical location for such a cold source was the HB-4 beam tube. This location provides a potential flux environment higher than the Institut Laue-Langevin (ILL) vertical cold source and maximizes the space available for a future cold neutron guide hall expansion. It was determined that this cold neutron beam would be comparable, in cold neutron brightness, to the best facilities in the world, and a decision was made to complete a preconceptual design study with the intention of proceeding with an activity to install a working LH2 cold source in the HFIR HB-4 beam tube. During the development of the reference design the liquid hydrogen concept was changed to a supercritical hydrogen system for a number of reasons. This report documents the reference supercritical hydrogen design and its performance. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and testing, (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the conceptual design phase and establishes the baseline reference concept

  9. High Flux Isotope Reactor cold neutron source reference design concept

    Energy Technology Data Exchange (ETDEWEB)

    Selby, D.L.; Lucas, A.T.; Hyman, C.R. [and others

    1998-05-01

    In February 1995, Oak Ridge National Laboratory`s (ORNL`s) deputy director formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. In May 1995, a team was formed to examine the feasibility of retrofitting a liquid hydrogen (LH{sub 2}) cold source facility into an existing HFIR beam tube. The results of this feasibility study indicated that the most practical location for such a cold source was the HB-4 beam tube. This location provides a potential flux environment higher than the Institut Laue-Langevin (ILL) vertical cold source and maximizes the space available for a future cold neutron guide hall expansion. It was determined that this cold neutron beam would be comparable, in cold neutron brightness, to the best facilities in the world, and a decision was made to complete a preconceptual design study with the intention of proceeding with an activity to install a working LH{sub 2} cold source in the HFIR HB-4 beam tube. During the development of the reference design the liquid hydrogen concept was changed to a supercritical hydrogen system for a number of reasons. This report documents the reference supercritical hydrogen design and its performance. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and testing, (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the conceptual design phase and establishes the baseline reference concept.

  10. Proceedings of the Oak Ridge National Laboratory/Brookhaven National Laboratory workshop on neutron scattering instrumentation at high-flux reactors

    International Nuclear Information System (INIS)

    For the first three decades following World War II, the US, which pioneered the field of neutron scattering research, enjoyed uncontested leadership in the field. By the mid-1970's, other countries, most notably through the West European consortium at Institut Laue-Langevin (ILL) in Grenoble, France, had begun funding neutron scattering on a scale unmatched in this country. By the early 1980's, observers charged with defining US scientific priorities began to stress the need for upgrading and expansion of US research reactor facilities. The conceptual design of the ANS facility is now well under way, and line-item funding for more advanced design is being sought for FY 1992. This should lead to a construction request in FY 1994 and start-up in FY 1999, assuming an optimal funding profile. While it may be too early to finalize designs for instruments whose construction is nearly a decade removed, it is imperative that we begin to develop the necessary concepts to ensure state-of-the-art instrumentation for the ANS. It is in this context that this Instrumentation Workshop was planned. The workshop touched upon many ideas that must be considered for the ANS, and as anticipated, several of the discussions and findings were relevant to the planning of the HFBR Upgrade. In addition, this report recognizes numerous opportunities for further breakthroughs on neutron instrumentation in areas such as improved detection schemes (including better tailored scintillation materials and image plates, and increased speed in both detection and data handling), in-beam monitors, transmission white beam polarizers, multilayers and supermirrors, and more. Each individual report has been cataloged separately

  11. Final Report Independent Verification Survey of the High Flux Beam Reactor, Building 802 Fan House Brookhaven National Laboratory Upton, New York

    Energy Technology Data Exchange (ETDEWEB)

    Evan Harpeneau

    2011-06-24

    The Separations Process Research Unit (SPRU) complex located on the Knolls Atomic Power Laboratory (KAPL) site in Niskayuna, New York, was constructed in the late 1940s to research the chemical separation of plutonium and uranium (Figure A-1). SPRU operated as a laboratory scale research facility between February 1950 and October 1953. The research activities ceased following the successful development of the reduction oxidation and plutonium/uranium extraction processes. The oxidation and extraction processes were subsequently developed for large scale use by the Hanford and Savannah River sites (aRc 2008a). Decommissioning of the SPRU facilities began in October 1953 and continued through the 1990s.

  12. Final Report Independent Verification Survey of the High Flux Beam Reactor, Building 802 Fan House Brookhaven National Laboratory Upton, New York DCN: 5098-SR-06-0

    International Nuclear Information System (INIS)

    The Separations Process Research Unit (SPRU) complex located on the Knolls Atomic Power Laboratory (KAPL) site in Niskayuna, New York, was constructed in the late 1940s to research the chemical separation of plutonium and uranium (Figure A-1). SPRU operated as a laboratory scale research facility between February 1950 and October 1953. The research activities ceased following the successful development of the reduction oxidation and plutonium/uranium extraction processes. The oxidation and extraction processes were subsequently developed for large scale use by the Hanford and Savannah River sites (aRc 2008a). Decommissioning of the SPRU facilities began in October 1953 and continued through the 1990s.

  13. A new high-flux solar furnace for high-temperature thermochemical research

    Energy Technology Data Exchange (ETDEWEB)

    Haueter, P.; Seitz, T.; Steinfeld, A. [Paul Scherrer Inst., Villigen (Switzerland). Solar Process Technology Group

    1999-02-01

    A new high-flux solar furnace, capable of delivering up to 40 kW at peak concentration ratios exceeding 5000, is operational at PSI. Its optical design characteristics, main engineering features, and operating performance are described. This solar concentrating facility will be used principally for investigating the thermochemical processing of solar fuels at temperatures as high as 2500 K.

  14. A Compact, High-Flux Cold Atom Beam Source

    Science.gov (United States)

    Kellogg, James R.; Kohel, James M.; Thompson, Robert J.; Aveline, David C.; Yu, Nan; Schlippert, Dennis

    2012-01-01

    The performance of cold atom experiments relying on three-dimensional magneto-optical trap techniques can be greatly enhanced by employing a highflux cold atom beam to obtain high atom loading rates while maintaining low background pressures in the UHV MOT (ultra-high vacuum magneto-optical trap) regions. Several techniques exist for generating slow beams of cold atoms. However, one of the technically simplest approaches is a two-dimensional (2D) MOT. Such an atom source typically employs at least two orthogonal trapping beams, plus an additional longitudinal "push" beam to yield maximum atomic flux. A 2D atom source was created with angled trapping collimators that not only traps atoms in two orthogonal directions, but also provides a longitudinal pushing component that eliminates the need for an additional push beam. This development reduces the overall package size, which in turn, makes the 2D trap simpler, and requires less total optical power. The atom source is more compact than a previously published effort, and has greater than an order of magnitude improved loading performance.

  15. Safety and quality management at the high flux reactor Petten

    International Nuclear Information System (INIS)

    The High Flux Reactor (HFR) is one high power multi-purpose materials testing research reactor of the tank-in-pool type, cooled and moderated by light-water. It is operated at 45 MW at a prescribed schedule of 11 cycles per year, each comprising 25 operation days and three shut-down days. Since the licence for the operation of HFR was granted in 1962, a total of 14 amendments to the original licence have been made following different modifications in the installations. In the meantime, international nuclear standards were developed, especially in the framework of the NUSS programme of the IAEA, which were adopted by the Dutch Licensing Authorities. In order to implement the new standards, the situation at the HFR was comprehensively reviewed in the course of an audit performed by the Dutch Licensing Authorities in 1988. This also resulted in formulating the task of setting-up an 'HFR - Integral Quality Assurance Handbook' (HFR-IQAD) involving both organizations JRCIAM and ECN, which had the unique framework and basic guideline to assure the safe and efficient operation and exploitation of the HFR and to promote safety and quality in all aspects of HFR related activities. The assurance of safe and efficient operation and exploitation of the HFR is condensed together under the concepts of safety and quality of services and is achieved through the safety and quality management. (orig.)

  16. Extraction of gadolinium from high flux isotope reactor control plates

    International Nuclear Information System (INIS)

    Gadolinium-153 is an important radioisotope used in the diagnosis of various bone disorders. Recent medical and technical developments in the detection and cure of osteoporosis, a bone disease affecting an estimated 50 million people, have greatly increased the demand for this isotope. The Oak Ridge National Laboratory (ORNL) has produced 153Gd since 1980 primarily through the irradiation of a natural europium-oxide powder followed by the chemical separation of the gadolinium fraction from the europium material. Due to the higher demand for 153Gd, an alternative production method to supplement this process has been investigated. This process involves the extraction of gadolinium from the europium-bearing region of highly radioactive, spent control plates used at the High Flux Isotope Reactor (HFIR) with a subsequent re-irradiation of the extracted material for the production of the 153Gd. Based on the results of experimental and calculational analyses, up to 25 grams of valuable gadolinium (≥60% enriched in 152Gd) resides in the europium-bearing region of the HFIR control components of which 70% is recoverable. At a specific activity yield of 40 curies of 153Gd for each gram of gadolinium re-irradiated, 700 one-curie sources can be produced from each control plate assayed

  17. Neutron scattering at the high-flux isotope reactor

    International Nuclear Information System (INIS)

    The title facilities offer the brightest source of neutrons in the national user program. Neutron scattering experiments probe the structure and dynamics of materials in unique and complementary ways as compared to x-ray scattering methods and provide fundamental data on materials of interest to solid state physicists, chemists, biologists, polymer scientists, colloid scientists, mineralogists, and metallurgists. Instrumentation at the High- Flux Isotope Reactor includes triple-axis spectrometers for inelastic scattering experiments, a single-crystal four diffractometer for crystal structural studies, a high-resolution powder diffractometer for nuclear and magnetic structure studies, a wide-angle diffractometer for dynamic powder studies and measurements of diffuse scattering in crystals, a small-angle neutron scattering (SANS) instrument used primarily to study structure-function relationships in polymers and biological macromolecules, a neutron reflectometer for studies of surface and thin-film structures, and residual stress instrumentation for determining macro- and micro-stresses in structural metals and ceramics. Research highlights of these areas will illustrate the current state of neutron science to study the physical properties of materials

  18. Nuclear medicine at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Atkins, H.L.

    1976-01-01

    The Nuclear Medicine Program at the Brookhaven National Laboratory seeks to develop new materials and methods for the investigation of human physiology and disease processes. Some aspects of this research are related to basic research of how radiopharmaceuticals work. Other aspects are directed toward direct applications as diagnostic agents. It is likely that cyclotron-produced positron emitting nuclides will assume greater importance in the next few years. This can be attributed to the ability to label biologically important molecules with high specific activity without affecting biological activity, using /sup 11/C, /sup 13/N, and /sup 15/O. Large quantities of these short-lived nuclides can be administered without excessive radiation dose and newer instrumentation will permit reconstructive axial tomography, providing truly quantitative display of distribution of radioactivity. The /sup 122/Xe-/sup 122/I generator has the potential for looking at rapid dynamic processes. Another generator, the /sup 68/Ge-/sup 68/Ga generator produces a positron emitter for the use of those far removed from cyclotrons. The possibilities for /sup 68/Ga radiopharmaceuticals are as numerous as those for /sup 99m/Tc diagnostic agents.

  19. Geothermal materials development at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kukacka, L.E. [Brookhaven National Lab., Upton, NY (United States)

    1997-12-31

    As part of the DOE/OGT response to recommendations and priorities established by industrial review of their overall R&D program, the Geothermal Materials Program at Brookhaven National Laboratory (BNL) is focusing on topics that can reduce O&M costs and increase competitiveness in foreign and domestic markets. Corrosion and scale control, well completion materials, and lost circulation control have high priorities. The first two topics are included in FY 1997 BNL activities, but work on lost circulation materials is constrained by budgetary limitations. The R&D, most of which is performed as cost-shared efforts with U.S. geothermal firms, is rapidly moving into field testing phases. FY 1996 and 1997 accomplishments in the development of lightweight CO{sub 2}-resistant cements for well completions; corrosion resistant, thermally conductive polymer matrix composites for heat exchange applications; and metallic, polymer and ceramic-based corrosion protective coatings are given in this paper. In addition, plans for work that commenced in March 1997 on thermally conductive cementitious grouting materials for use with geothermal heat pumps (GHP), are discussed.

  20. High flux and high resolution VUV beam line for synchrotron radiation

    International Nuclear Information System (INIS)

    A beam line has been optimized for high flux and high resolution in the wavelength range from 30 nm to 300 nm. Sample chambers for luminescence spectroscopy on gaseous, liquid and solid samples and for photoelectron spectroscopy have been integrated. The synchrotron radiation from the storage ring DORIS (at DESY, Hamburg) emitted into 50 mrad in horizontal and into 2.2 mrad in vertical direction is focused by a cylindrical and a plane elliptical mirror into the entrance slit of a 2m normal incidence monochromator. The light flux from the exit slit is focused by a rotational elliptic mirror onto the sample yielding a size of the light spot of 4 x 0.15 mm2. The light flux at the sample reaches 7 x 1012 photons nm-1s-1 at 8 eV photon energy for a current of 100 mA in DORIS. A resolution of 0.007 nm has been obtained. (orig.)

  1. Flux-measuring approach of high temperature metal liquid based on BP neural networks

    Institute of Scientific and Technical Information of China (English)

    胡燕瑜; 桂卫华; 李勇刚

    2003-01-01

    A soft-measuring approach is presented to measure the flux of liquid zinc with high temperature andcausticity. By constructing mathematical model based on neural networks, weighing the mass of liquid zinc, the fluxof liquid zinc is acquired indirectly, the measuring on line and flux control are realized. Simulation results and indus-trial practice demonstrate that the relative error between the estimated flux value and practical measured flux value islower than 1.5%, meeting the need of industrial process.

  2. Organic cooled high flux, heating element working under radiations

    International Nuclear Information System (INIS)

    Heating elements described in this report are heated by direct or alternative current in the wall cooled by the liquid. The element temperature can be 500 deg. C and the heat flux in the test section 100 Watts/sq.cm. The type of heating element used in a loop working under an accelerator is supplied by a low voltage high current (1500 amps). This type is relatively simple, robust and convenient for experiments. When the heating element is used in loop l aided near the core of a research reactor, it is supplied with a lower electric current (750 amps). This improved type is more complicate and fragile due to the conditions of working and the safety device necessary for a reactor. The heating stainless steel pipe has an outside diameter of 20 mm and a thickness of 0.15 mm. We give the elements of calculation for this heating elements, a description of the two types built, and a report of the tests made by the constructor on a technological test loop. (author)

  3. Fabrication of control rods for the High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    The High Flux Isotope Reactor (HFIR) is a research-type nuclear reactor that was designed and built in the early 1960s and has been in continuous operation since its initial criticality in 1965. Under current plans, the HFIR is expected to continue in operation until 2035. This report updates ORNL/TM-9365, Fabrication Procedure for HFIR Control Plates, which was mainly prepared in the early 1970's but was not issued until 1984, and reflects process changes, lessons learned in the latest control rod fabrication campaign, and suggested process improvements to be considered in future campaigns. Most of the personnel involved with the initial development of the processes and in part campaigns have retired or will retire soon. Because their unlikely availability in future campaigns, emphasis has been placed on providing some explanation of why the processes were selected and some discussions about the importance of controlling critical process parameters. Contained in this report is a description of the function of control rods in the reactor, the brief history of the development of control rod fabrication processes, and a description of procedures used in the fabrication of control rods. A listing of the controlled documents and procedures used in the last fabrication campaigns is referenced in Appendix A

  4. High Flux Isotope Reactor system RELAP5 input model

    International Nuclear Information System (INIS)

    A thermal-hydraulic computational model of the High Flux Isotope Reactor (HFIR) has been developed using the RELAP5 program. The purpose of the model is to provide a state-of-the art thermal-hydraulic simulation tool for analyzing selected hypothetical accident scenarios for a revised HFIR Safety Analysis Report (SAR). The model includes (1) a detailed representation of the reactor core and other vessel components, (2) three heat exchanger/pump cells, (3) pressurizing pumps and letdown valves, and (4) secondary coolant system (with less detail than the primary system). Data from HFIR operation, component tests, tests in facility mockups and the HFIR, HFIR specific experiments, and other pertinent experiments performed independent of HFIR were used to construct the model and validate it to the extent permitted by the data. The detailed version of the model has been used to simulate loss-of-coolant accidents (LOCAs), while the abbreviated version has been developed for the operational transients that allow use of a less detailed nodalization. Analysis of station blackout with core long-term decay heat removal via natural convection has been performed using the core and vessel portions of the detailed model

  5. High Flux Isotope Reactor system RELAP5 input model

    Energy Technology Data Exchange (ETDEWEB)

    Morris, D.G.; Wendel, M.W.

    1993-01-01

    A thermal-hydraulic computational model of the High Flux Isotope Reactor (HFIR) has been developed using the RELAP5 program. The purpose of the model is to provide a state-of-the art thermal-hydraulic simulation tool for analyzing selected hypothetical accident scenarios for a revised HFIR Safety Analysis Report (SAR). The model includes (1) a detailed representation of the reactor core and other vessel components, (2) three heat exchanger/pump cells, (3) pressurizing pumps and letdown valves, and (4) secondary coolant system (with less detail than the primary system). Data from HFIR operation, component tests, tests in facility mockups and the HFIR, HFIR specific experiments, and other pertinent experiments performed independent of HFIR were used to construct the model and validate it to the extent permitted by the data. The detailed version of the model has been used to simulate loss-of-coolant accidents (LOCAs), while the abbreviated version has been developed for the operational transients that allow use of a less detailed nodalization. Analysis of station blackout with core long-term decay heat removal via natural convection has been performed using the core and vessel portions of the detailed model.

  6. Operation of the High Flux Reactor. Annual report 1985

    International Nuclear Information System (INIS)

    This year was characterized by the end of a major rebuilding of the installation during which the reactor vessel and its peripheral components were replaced by new and redesigned equipment. Both operational safety and experimental use were largely improved by the replacement. The reactor went back to routine operation on February 14, 1985, and has been operating without problem since then. All performance parameters were met. Other upgrading actions started during the year concerned new heat exchangers and improvements to the reactor building complex. The experimental load of the High Flux Reactor reached a satisfactory level with an average of 57%. New developments aimed at future safety related irradiation tests and at novel applications of neutrons from the horizontal beam tubes. A unique remote encapsulation hot cell facility became available adding new possibilities for fast breeder fuel testing and for intermediate specimen examination. The HFR Programme hosted an international meeting on development and use of reduced enrichment fuel for research reactors. All aspects of core physics, manufacture technology, and licensing of novel, proliferation-free, research reactor fuel were debated

  7. Fabrication of control rods for the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sease, J.D.

    1998-03-01

    The High Flux Isotope Reactor (HFIR) is a research-type nuclear reactor that was designed and built in the early 1960s and has been in continuous operation since its initial criticality in 1965. Under current plans, the HFIR is expected to continue in operation until 2035. This report updates ORNL/TM-9365, Fabrication Procedure for HFIR Control Plates, which was mainly prepared in the early 1970's but was not issued until 1984, and reflects process changes, lessons learned in the latest control rod fabrication campaign, and suggested process improvements to be considered in future campaigns. Most of the personnel involved with the initial development of the processes and in part campaigns have retired or will retire soon. Because their unlikely availability in future campaigns, emphasis has been placed on providing some explanation of why the processes were selected and some discussions about the importance of controlling critical process parameters. Contained in this report is a description of the function of control rods in the reactor, the brief history of the development of control rod fabrication processes, and a description of procedures used in the fabrication of control rods. A listing of the controlled documents and procedures used in the last fabrication campaigns is referenced in Appendix A.

  8. Intergrain flux creep in high-Tc superconductors

    International Nuclear Information System (INIS)

    Equations describing the intergrain flux creep of ceramic superconductors are derived. They are based on the behavior of small superconducting loops closed by overdamped Josephson junctions. The elementary loops are formed around nonsuperconducting regions between the grains, the loops acting as pinning centers. Despite different pinning mechanisms the equations for the relaxation of the intergrain current density in a static and a slowly varying external magnetic field are formally similar to those of the classical flux-creep theory based on volume pinning

  9. The High Flux Reactor Petten, present status and prospects

    International Nuclear Information System (INIS)

    The High Flux Reactor (HFR) in Petten, The Netherlands, is a light water cooled and moderated multipurpose research reactor of the closed-tank in pool type. It is operated with highly enriched Uranium fuel at a power of 45 MW. The reactor is owned by the European Communities and operated under contract by the Dutch ECN. The HFR programme is funded by The Netherlands and Germany, a smaller share comes from the specific programmes of the Joint Research Centre (JRC) and from third party contract work. Since its first criticality in 1961 the reactor has been continuously upgraded by implementing developments in fuel element technology and increasing the power from 20 MW to the present 45 MV. In 1984 the reactor vessel was replaced by a new one with an improved accessibility for experiments. In the following years also other ageing equipment has been replaced (primary heat exchangers, pool heat exchanger, beryllium reflector elements, nuclear and process instrumentation, uninterruptable power supply). Control room upgrading is under preparation. A new safety analysis is near to completion and will form the basis for a renewed license. The reactor is used for nuclear energy related research (structural materials and fuel irradiations for LWR's, HTR's and FBR's, fusion materials irradiations). The beam tubes are used for nuclear physics as well as solid state and materials sciences. Radioisotope production at large scale, processing of gemstones and silicon with neutrons, neutron radiography and activation analysis are actively pursued. A clinical facility for boron neutron capture therapy is being designed at one of the large cross section beam tubes. It is foreseen to operate the reactor at least for a further decade. The exploitation pattern may undergo some changes depending on the requirements of the supporting countries and the JRC programmes. (author)

  10. Level 1 Tornado PRA for the High Flux Beam Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bozoki, G.E.; Conrad, C.S.

    1994-05-01

    This report describes a risk analysis primarily directed at providing an estimate for the frequency of tornado induced damage to the core of the High Flux Beam Reactor (HFBR), and thus it constitutes a Level 1 Probabilistic Risk Assessment (PRA) covering tornado induced accident sequences. The basic methodology of the risk analysis was to develop a ``tornado specific`` plant logic model that integrates the internal random hardware failures with failures caused externally by the tornado strike and includes operator errors worsened by the tornado modified environment. The tornado hazard frequency, as well as earlier prepared structural and equipment fragility data, were used as input data to the model. To keep modeling/calculational complexity as simple as reasonable a ``bounding`` type, slightly conservative, approach was applied. By a thorough screening process a single dominant initiating event was selected as a representative initiator, defined as: ``Tornado Induced Loss of Offsite Power.`` The frequency of this initiator was determined to be 6.37E-5/year. The safety response of the HFBR facility resulted in a total Conditional Core Damage Probability of .621. Thus, the point estimate of the HFBR`s Tornado Induced Core Damage Frequency (CDF) was found to be: (CDF){sub Tornado} = 3.96E-5/year. This value represents only 7.8% of the internal CDF and thus is considered to be a small contribution to the overall facility risk expressed in terms of total Core Damage Frequency. In addition to providing the estimate of (CDF){sub Tornado}, the report documents, the relative importance of various tornado induced system, component, and operator failures that contribute most to (CDF){sub Tornado}.

  11. High flux isotope reactor cold source preconceptual design study report

    International Nuclear Information System (INIS)

    In February 1995, the deputy director of Oak Ridge National Laboratory (ORNL) formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced Neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. The anticipated cold source will consist of a cryogenic LH2 moderator plug, a cryogenic pump system, a refrigerator that uses helium gas as a refrigerant, a heat exchanger to interface the refrigerant with the hydrogen loop, liquid hydrogen transfer lines, a gas handling system that includes vacuum lines, and an instrumentation and control system to provide constant system status monitoring and to maintain system stability. The scope of this project includes the development, design, safety analysis, procurement/fabrication, testing, and installation of all of the components necessary to produce a working cold source within an existing HFIR beam tube. This project will also include those activities necessary to transport the cold neutron beam to the front face of the present HFIR beam room. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and research and development (R and D), (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the preconceptual phase and establishes the concept feasibility. The information presented includes the project scope, the preliminary design requirements, the preliminary cost and schedule, the preliminary performance data, and an outline of the various plans for completing the project

  12. Automated calculation of surface energy fluxes with high-frequency lake buoy data

    Science.gov (United States)

    Woolway, R Iestyn; Jones, Ian D; Hamilton, David P.; Maberly, Stephen C; Muroaka, Kohji; Read, Jordan S.; Smyth, Robyn L; Winslow, Luke A.

    2015-01-01

    Lake Heat Flux Analyzer is a program used for calculating the surface energy fluxes in lakes according to established literature methodologies. The program was developed in MATLAB for the rapid analysis of high-frequency data from instrumented lake buoys in support of the emerging field of aquatic sensor network science. To calculate the surface energy fluxes, the program requires a number of input variables, such as air and water temperature, relative humidity, wind speed, and short-wave radiation. Available outputs for Lake Heat Flux Analyzer include the surface fluxes of momentum, sensible heat and latent heat and their corresponding transfer coefficients, incoming and outgoing long-wave radiation. Lake Heat Flux Analyzer is open source and can be used to process data from multiple lakes rapidly. It provides a means of calculating the surface fluxes using a consistent method, thereby facilitating global comparisons of high-frequency data from lake buoys.

  13. Autonomous, high-resolution observations of particle flux in the oligotrophic ocean

    Directory of Open Access Journals (Sweden)

    M. L. Estapa

    2013-08-01

    Full Text Available Observational gaps limit our understanding of particle flux attenuation through the upper mesopelagic because available measurements (sediment traps and radiochemical tracers have limited temporal resolution, are labor-intensive, and require ship support. Here, we conceptually evaluate an autonomous, optical proxy-based method for high-resolution observations of particle flux. We present four continuous records of particle flux collected with autonomous profiling floats in the western Sargasso Sea and the subtropical North Pacific, as well as one shorter record of depth-resolved particle flux near the Bermuda Atlantic Time-series Study (BATS and Oceanic Flux Program (OFP sites. These observations illustrate strong variability in particle flux over very short (~1-day timescales, but at longer timescales they reflect patterns of variability previously recorded during sediment trap time series. While particle flux attenuation at BATS/OFP agreed with the canonical power-law model when observations were averaged over a month, flux attenuation was highly variable on timescales of 1–3 days. Particle fluxes at different depths were decoupled from one another and from particle concentrations and chlorophyll fluorescence in the immediately overlying surface water, consistent with horizontal advection of settling particles. We finally present an approach for calibrating this optical proxy in units of carbon flux, discuss in detail the related, inherent physical and optical assumptions, and look forward toward the requirements for the quantitative application of this method in highly time-resolved studies of particle export and flux attenuation.

  14. Autonomous, high-resolution observations of particle flux in the oligotrophic ocean

    Directory of Open Access Journals (Sweden)

    M. L. Estapa

    2013-01-01

    Full Text Available Observational gaps limit our understanding of particle flux attenuation through the upper mesopelagic because available measurements (sediment traps and radiochemical tracers have limited temporal resolution, are labor-intensive, and require ship support. Here, we conceptually evaluate an autonomous, optical proxy-based method for high-resolution observations of particle flux. We present four continuous records of particle flux collected with autonomous, profiling floats in the western Sargasso Sea and the subtropical North Pacific, as well as one shorter record of depth-resolved particle flux near the Bermuda Atlantic Timeseries Study (BATS and Oceanic Flux Program (OFP sites. These observations illustrate strong variability in particle flux over very short (~1 day timescales, but at longer timescales they reflect patterns of variability previously recorded during sediment trap timeseries. While particle flux attenuation at BATS/OFP agreed with the canonical power-law model when observations were averaged over a month, flux attenuation was highly variable on timescales of 1–3 days. Particle fluxes at different depths were decoupled from one another and from particle concentrations and chlorophyll fluorescence in the immediately-overlying surface water, consistent with horizontal advection of settling particles. We finally present an approach for calibrating this optical proxy in units of carbon flux, discuss in detail the related, inherent physical and optical assumptions, and look forward toward the requirements for the quantitative application of this method in highly time-resolved studies of particle export and flux attenuation.

  15. Critical Heat Flux Phenomena at HighPressure & Low Mass Fluxes: NEUP Final Report Part I: Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Corradini, Michael [Univ. of Wisconsin, Madison, WI (United States); Wu, Qiao [Oregon State Univ., Corvallis, OR (United States)

    2015-04-30

    This report is a preliminary document presenting an overview of the Critical Heat Flux (CHF) phenomenon, the High Pressure Critical Heat Flux facility (HPCHF), preliminary CHF data acquired, and the future direction of the research. The HPCHF facility has been designed and built to study CHF at high pressure and low mass flux ranges in a rod bundle prototypical of conceptual Small Modular Reactor (SMR) designs. The rod bundle is comprised of four electrically heated rods in a 2x2 square rod bundle with a prototypic chopped-cosine axial power profile and equipped with thermocouples at various axial and circumferential positions embedded in each rod for CHF detection. Experimental test parameters for CHF detection range from pressures of ~80 – 160 bar, mass fluxes of ~400 – 1500 kg/m2s, and inlet water subcooling from ~30 – 70°C. The preliminary data base established will be further extended in the future along with comparisons to existing CHF correlations, models, etc. whose application ranges may be applicable to the conditions of SMRs.

  16. Search for a diffuse flux of high-energy $\

    CERN Document Server

    Aguilar, J A; Albert, A; André, M; Anghinolfi, M; Anton, G; Anvar, S; Ardid, M; Jesus, A C Assis; Astraatmadja, T; Aubert, J-J; Auer, R; Baret, B; Basa, S; Bazzotti, M; Bertin, V; Biagi, S; Bigongiari, C; Bogazzi, C; Bou-Cabo, M; Bouwhuis, M C; Brown, A M; Brunner, J; Busto, J; Camarena, F; Capone, A; Carloganu, C; Carminati, G; Carr, J; Cecchini, S; Charvis, Ph; Chiarusi, T; Circella, M; Coniglione, R; Costantini, H; Cottini, N; Coyle, P; Curtil, C; Decowski, M P; Dekeyser, I; Deschamps, A; Donzaud, C; Dornic, D; Dorosti, Q; Drouhin, D; Eberl, T; Emanuele, U; Ernenwein, J-P; Escoffier, S; Fehr, F; Flaminio, V; Folger, F; Fritsch, U; Fuda, J-L; Galata, S; Gay, P; Giacomelli, G; Gomez-Gonzalez, J P; Graf, K; Guillard, G; Halladjian, G; Hallewell, G; van Haren, H; Heijboer, A J; Hello, Y; Hernandez-Rey, J J; Herold, B; Hossl, J; Hsu, C C; de Jong, M; Kadler, M; Kalantar-Nayestanaki, N; Kalekin, O; Kappes, A; Katz, U; Kooijman, P; Kopper, C; Kouchner, A; Kulikovskiy, V; Lahmann, R; Lamare, P; Larosa, G; Lefèvre, D; Lim, G; Presti, D Lo; Loehner, H; Loucatos, S; Lucarelli, F; Mangano, S; Marcelin, M; Margiotta, A; Martinez-Mora, J A; Mazure, A; Meli, A; Montaruli, T; Morganti, M; Moscoso, L; Motz, H; Naumann, C; Neff, M; Palioselitis, D; Pavalas, G E; Payre, P; Petrovic, J; Piattelli, P; Picot-Clemente, N; Picq, C; Popa, V; Pradier, T; Presani, E; Racca, C; Reed, C; Riccobene, G; Richardt, C; Roensch, K; Rostovtsev, A; Rujoiu, M; Russo, G V; Salesa, F; Sapienza, P; Schock, F; Schuller, J-P; Shanidze, R; Simeone, F; Spies, A; Spurio, M; Steijger, J J M; Stolarczyk, Th; Taiuti, M; Tamburini, C; Tasca, L; Toscano, S; Vallage, B; Van Elewyck, V; Vannoni, G; Vecchi, M; Vernin, P; Wijnker, G; de Wolf, E; Yepes, H; Zaborov, D; Zornoza, J D; Zuniga, J

    2010-01-01

    A search for a diffuse flux of astrophysical muon neutrinos, using data collected by the ANTARES neutrino telescope is presented. A $(0.83\\times 2\\pi)$ sr sky was monitored for a total of 334 days of equivalent live time. The searched signal corresponds to an excess of events, produced by astrophysical sources, over the expected atmospheric neutrino background. The observed number of events is found compatible with the background expectation. Assuming an $E^{-2}$ flux spectrum, a 90% c.l. upper limit on the diffuse $\

  17. Elastic neutrino electron scattering at Brookhaven

    International Nuclear Information System (INIS)

    A progress report is given of Experiment 734 at Brookhaven, with a focus on the elastic reactions nu/sub μ/ + e- → nu/sub μ/ + e- and anti nu/sub μ/ + e- → anti nu/sub μ/ + e-. The present status, recent results, and future plans are discussed

  18. Dr. Praveen Chaudhari named director of Brookhaven National Laboratory

    CERN Multimedia

    2003-01-01

    "Brookhaven Science Associates announced today the selection of Dr. Praveen Chaudhari as Director of the U.S. Department of Energy's Brookhaven National Laboratory. Dr. Chaudhari, who will begin his new duties on April 1, joins Brookhaven Lab after 36 years of distinguished service at IBM as a scientist and senior manager of research" (1 page).

  19. Surface morphology and deuterium retention in tungsten exposed to high flux D plasma at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Y.Z. [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); De Temmerman, G. [FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Edisonbaan 14, 3439 MN Nieuwegein (Netherlands); ITER Organization, Route de Vinon-sur-Verdon-CS90046, 13067 St Paul Lez Durance Cedex (France); Luo, G.-N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Xu, H.Y. [Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang, Sichuan 621907 (China); Li, C.; Fu, B.Q. [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, W., E-mail: liuw@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2015-02-15

    Surface modifications and deuterium retention induced in tungsten by high fluxes (10{sup 24} m{sup −2} s{sup −1}) low energy (38 eV) deuterium ions were studied as a function of surface temperature. Blister formation was studied by scanning electron microscopy and electron backscatter diffraction, while deuterium retention was measured by thermal desorption spectroscopy. Blisters are observed on the surface exposed at different temperatures, ranging from 493 K to 1273 K. The blister density and D retention decrease with the increasing exposure temperature. The formation of blisters at high temperatures is attributed to the high flux of D plasma. At 943 K, with the increasing fluence, there is trend to the saturation of D retention and blister density. The defects caused by plasma exposure have an important effect on the D trapping and blistering behavior. The formation of blisters has a strong relationship with slipping system of tungsten.

  20. Proceedings of Brookhaven National Laboratory's fusion/synfuel workshop

    International Nuclear Information System (INIS)

    The fusion synfuels workshop held at Brookhaven National Laboratory (BNL) on August 27-29, 1979 examined the current status of candidate synfuel processes and the R and D required to develop the capability for fusion synfuel production. Participants divided into five working groups, covering the following areas: (1) economics and applications; (2) high-temperature electrolysis; (3) thermochemical processes (including hybrid thermo-electrochemical); (4) blanket and materials; and (5) high-efficiency power cycles. Each working group presented a summary of their conclusions and recommendations to all participants during the third day of the Workshop. These summaries are given

  1. High Flux Isotopes Reactor (HFIR) Cooling Towers Demolition Waste Management

    International Nuclear Information System (INIS)

    This paper describes the results of a joint initiative between Oak Ridge National Laboratory, operated by UT-Battelle, and Bechtel Jacobs Company, LLC (BJC) to characterize, package, transport, treat, and dispose of demolition waste from the High Flux Isotope Reactor (HFIR), Cooling Tower. The demolition and removal of waste from the site was the first critical step in the planned HFIR beryllium reflector replacement outage scheduled. The outage was scheduled to last a maximum of six months. Demolition and removal of the waste was critical because a new tower was to be constructed over the old concrete water basin. A detailed sampling and analysis plan was developed to characterize the hazardous and radiological constituents of the components of the Cooling Tower. Analyses were performed for Resource Conservation and Recovery Act (RCRA) heavy metals and semi-volatile constituents as defined by 40 CFR 261 and radiological parameters including gross alpha, gross beta, gross gamma, alpha-emitting isotopes and beta-emitting isotopes. Analysis of metals and semi-volatile constituents indicated no exceedances of regulatory limits. Analysis of radionuclides identified uranium and thorium and associated daughters. In addition 60Co, 99Tc, 226Rm, and 228Rm were identified. Most of the tower materials were determined to be low level radioactive waste. A small quantity was determined not to be radioactive, or could be decontaminated. The tower was dismantled October 2000 to January 2001 using a detailed step-by-step process to aid waste segregation and container loading. The volume of waste as packaged for treatment was approximately 1982 cubic meters (70,000 cubic feet). This volume was comprised of plastic (∼47%), wood (∼38%) and asbestos transite (∼14%). The remaining ∼1% consisted of the fire protection piping (contaminated with lead-based paint) and incidental metal from conduit, nails and braces/supports, and sludge from the basin. The waste, except for the

  2. Operational research on a high-T c rectifier-type superconducting flux pump

    Science.gov (United States)

    Geng, Jianzhao; Matsuda, K.; Fu, Lin; Shen, Boyang; Zhang, Xiuchang; Coombs, T. A.

    2016-03-01

    High-T c superconducting (HTS) flux pumps are capable of injecting flux into a superconducting circuit, which can achieve persistent current operation for HTS magnets. In this paper, we studied the operation of a rectifier-type HTS flux pump. The flux pump employs a transformer to generate high alternating current in its secondary winding, which is connected to an HTS load shorted by an HTS bridge. A high frequency ac field is intermittently applied perpendicular to the bridge, thus, generating flux flow. The dynamic resistance caused by the flux flow ‘rectifies’ the secondary current, resulting in a direct current in the load. We have found that the final load current can easily be controlled by changing the phase difference between the secondary current and the bridge field. The bridge field of frequency ranging from 10 to 40 Hz and magnitude ranging from 0 to 0.66 T was tested. Flux pumping was observed for field magnitudes of 50 mT or above. We have found that both higher field magnitude and higher field frequency result in a faster pumping speed and a higher final load current. This can be attributed to the influence of dynamic resistance. The dynamic resistance measured in the flux pump is comparable with the theoretical calculation. The experimental results fully support a first order circuit model. The flux pump is much more controllable than the traveling wave flux pumps based on permanent magnets, which makes it promising for practical use.

  3. Countercurrent flow limited (CCFL) heat flux in the high flux isotope reactor (HFIR) fuel element

    International Nuclear Information System (INIS)

    The countercurrent flow (CCF) performance in the fuel element region of the HFIR is examined experimentally and theoretically. The fuel element consists of two concentric annuli filled with aluminum clad fuel plates of 1.27 mm thickness separated by 1.27 mm flow channels. The plates are curved as they go radially outward to accomplish constant flow channel width and constant metal-to-coolant ratio. A full-scale HFIR fuel element mock-up is studied in an adiabatic air-water CCF experiment. A review of CCF models for narrow channels is presented along with the treatment of CCFs in system of parallel channels. The experimental results are related to the existing models and a mechanistic model for the ''annular'' CCF in a narrow channel is developed that captures the data trends well. The results of the experiment are used to calculate the CCFL heat flux of the HFIR fuel assembly. It was determined that the HFIR fuel assembly can reject 0.62 Mw of thermal power in the CCFL situation. 31 refs., 17 figs

  4. COMPARISON OF COOLING SCHEMES FOR HIGH HEAT FLUX COMPONENTS COOLING IN FUSION REACTORS

    OpenAIRE

    Phani Kumar Domalapally; Slavomir Entler

    2015-01-01

    Some components of the fusion reactor receives high heat fluxes either during the startup and shutdown or during the operation of the machine. This paper analyzes different ways of enhancing heat transfer using helium and water for cooling of these high heat flux components and then conclusions are drawn to decide the best choice of coolant, for usage in near and long term applications.

  5. Use of CMOS imagers to measure high fluxes of charged particles

    Science.gov (United States)

    Servoli, L.; Tucceri, P.

    2016-03-01

    The measurement of high flux charged particle beams, specifically at medical accelerators and with small fields, poses several challenges. In this work we propose a single particle counting method based on CMOS imagers optimized for visible light collection, exploiting their very high spatial segmentation (> 3 106 pixels/cm2) and almost full efficiency detection capability. An algorithm to measure the charged particle flux with a precision of ~ 1% for fluxes up to 40 MHz/cm2 has been developed, using a non-linear calibration algorithm, and several CMOS imagers with different characteristics have been compared to find their limits on flux measurement.

  6. Hydrodynamic transition delay in rectangular channels under high heat flux

    International Nuclear Information System (INIS)

    When upgrading a research nuclear reactor for a higher power output it can be expected that the cooling flow rate has to be increased. In the case of a reactor designed with a laminar cooling flow this upgrade may take the flow into the transition hydrodynamic regime. In this work we explore experimentally the laminar to turbulent transition in a rectangular channel with similar characteristics as the refrigerating passages between the fuel plates in a research reactor core. The measurements were performed under heat fluxes up to 10 W/cm2, which is similar to the heat flux found in pool type research reactors. Special care has been taken in the test section to minimize the entrance turbulence and to reproduce the superficial characteristics of the aluminium cladding of the nuclear fuel. We have measured the transition Reynolds number as the bulk Reynolds number at the point of minimum Nusselt number for each condition studied. It was observed that the bulk Reynolds number at which the transition to turbulence is detected depends on the heat flux at the walls. This result is in agreement with a recent theoretical analysis, which shows that property variations near the wall, particularly the reduction of viscosity, have a stabilizing effect on the flow.

  7. Performance of high-accuracy schemes in inviscid fluxes calculation

    International Nuclear Information System (INIS)

    In this paper performance of first, second and third order accurate methods for calculation of inviscid fluxes in fluid flow governing equations are investigated. Accuracy, convergence rate, and shock capturing of these methods are discussed and advantages of each one are compared with the others. For this purpose an upwind method based on Roe's scheme is applied to solve 2-dimensional Euler equations. To increase the accuracy of the method two different schemes are applied. The first one is a second and third order upwind-based algorithm with the MUSCL extrapolation Van Leer (1979), based on primitive variables. The second one is upwind-based algorithm with the Chakravarthy extrapolation to the fluxes of mass, momentum and energy. In the above mentioned methods Van Albada et. al. flux limiter (1982) and minmod slope-limiter is applied, respectively. To confirm the validation of the presented schemes two test cases have been carried out including supersonic flow over a bump and a compression ramp. The results are compared with the results of other references. It has been shown that the thickness of shock layer in the third order accuracy is less than its value in second order. Applying limiter eliminates the oscillations near the shock but the thickness of shock layer will be more in MUSCL method. While in Chakravarthy method limiters eliminate oscillations and thickness of the shock layer remains constant. (author)

  8. A novel high temperature superconducting magnetic flux pump for MRI magnets

    Science.gov (United States)

    Bai, Zhiming; Yan, Guo; Wu, Chunli; Ding, Shufang; Chen, Chuan

    2010-10-01

    This paper presents a kind of minitype magnetic flux pump made of high temperature superconductor. This kind of novel high temperature superconducting (HTS) flux pump has not any mechanical revolving parts or thermal switches. The excitation current of copper coils in magnetic pole system is controlled by a singlechip. The structure design and operational principle have been described. The operating performance of the new model magnetic flux pump has been preliminarily tested. The experiments show that the maximum pumping current is approximately 200 A for Bi2223 flux pump and 80 A for MgB 2 flux pump operating at 20 K. By comparison, it is discovered that the operating temperature range is wider, the ripple is smaller and the pumping frequency is higher in Bi2223 flux pump than those in MgB 2 flux pump. These results indicate that the newly developed Bi2223 magnetic flux pump may efficiently compensate the magnetic field decay in HTS magnet and make the magnet operate in persistent current mode, this point is significant to the magnetic resonance imaging (MRI) magnets. This new flux pump is under construction presently. It is expected that the Bi2223 flux pump would be applied to the superconducting MRI magnets by further optimizing structure and improving working process.

  9. Brookhaven National Laboratory site environmental report for calendar year 1990

    International Nuclear Information System (INIS)

    Brookhaven National Laboratory (BNL) carries out basic and applied research in the following fields: high-energy nuclear and solid state physics; fundamental material and structure properties and the interactions of matter; nuclear medicine, biomedical and environmental sciences; and selected energy technologies. In conducting these research activities, it is Laboratory policy to protect the health and safety of employees and the public, and to minimize the impact of BNL operations on the environment. This document is the BNL environmental report for the calendar year 1990 for the safety and Environmental Protection division and corners topics on effluents, surveillance, regulations, assessments, and compliance

  10. Effect of high-flux astronomical sources on the constellation-X microcalorimeter spectrometer

    International Nuclear Information System (INIS)

    We study the effects of high flux on transition-edge sensors by using a non-linear microcalorimeter model with parameters suitable for the Constellation-X mission. A photon event list was created that simulated the flux and spectrum of the Crab nebula incident on the detector when folded through the Constellation-X optics and filters. Simulations show that even at Crab levels of flux, the Con-X microcalorimeter does not 'latch' into the normal state

  11. Dhruva reactor -- a high flux facility for neutron beam research

    International Nuclear Information System (INIS)

    Dhruva reactor, the highest flux thermal neutron source in India has been operating at full power of 100 MW over the past two years. Several advanced facilities like the cold source, guides, etc. are being installed for neutron beam research in condensed matter. A large number and variety of neutron spectrometers are operational. This paper deals with the basic advantages that one can derive from neutron scattering investigations and gives a brief description of the instruments that are developed and commissioned at Dhruva for neutron beam research. (author). 3 figs

  12. The Amtex DAMA Project: The Brookhaven contribution

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, A.M.

    1995-01-01

    The Amtex Partnership organized in 1993 as a Technology Transfer Collaboration among members of the integrated textile industry, the DOE National Laboratories, a number of universities, and several research/education/technology transfer organizations (RETTs). Under the Amtex umbrella organization, a number of technology areas were defined and individual projects were launched addressing various aspects of improving the health and competitiveness of the American textile industry. The first and, to date, the largest of these has been the computer-based Demand Activated Manufacturing Architecture (DAMA) project. Brookhaven National Laboratory became involved in DAMA beginning in March of 1993 and remained an active participant through January of 1995. It was staffed almost exclusively with personnel of the Computing and Communications Division. This document summarizes the activities and accomplishments of the Brookhaven team in working with the larger collaboration. Detailed information about the Amtex Partnership, the DAMA Project, and specific BNL contributions are documented elsewhere.

  13. Electronic Instability at High Flux-Flow Velocities in High-Tc Superconducting Films

    DEFF Research Database (Denmark)

    Doettinger, S. G.; Huebener, R. P.; Gerdemann, R.;

    1994-01-01

    At high flux-flow velocities in type-II superconductors the nonequilibrium distribution of the quasiparticles leads to an electronic instability and an aburpt switching into a state with higher electric resistivity, as predicted by Larkin and Ovchinnikow (LO). We report the first obervation of this...... effect in a high-temperature superconductor, namely in epitaxial c-axis oriented films of YBa(2)Cu3O(7)-(delta). Using the LO therory, we have extracted from out results the inelastic quasiparticle scattering rare tau(in)(-1), which strongly decreases with decreasing temperature below T-c...

  14. Database activities at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Brookhaven National Laboratory is a multi-disciplinary lab in the DOE system of research laboratories. Database activities are correspondingly diverse within the restrictions imposed by the dominant relational database paradigm. The authors discuss related activities and tools used in RHIC and in the other major projects at BNL. The others are the Protein Data Bank being maintained by the Chemistry department, and a Geographical Information System (GIS)--a Superfund sponsored environmental monitoring project under development in the Office of Environmental Restoration

  15. The Brookhaven electron analogue, 1953--1957

    International Nuclear Information System (INIS)

    The following topics are discussed on the Brookhaven electron analogue: L.J. Haworth and E.L. VanHorn letters; Original G.K. Green outline for report; General description; Parameter list; Mechanical Assembly; Alignment; Degaussing; Vacuum System; Injection System; The pulsed inflector; RF System; Ferrite Cavity; Pick-up electrodes and preamplifiers; Radio Frequency power amplifier; Lens supply; Controls and Power; and RF acceleration summary

  16. BLIP. [Brookhaven Linac Isotope Producer (BLIP)

    Energy Technology Data Exchange (ETDEWEB)

    Stang, Jr, L G

    1976-01-01

    The operation of the Brookhaven Linac Isotope Producer (BLIP) is discussed. Topics covered include targets, target holders, linac specifications, beam transport, and current production performance. The use of the BLIP is confined exclusively to the development of radionuclides that are, or should be, of medical interest, and the facility is moving rapidly into a self-supporting state from the income of the products. (PMA)

  17. The Brookhaven electron analogue, 1953--1957

    Energy Technology Data Exchange (ETDEWEB)

    Plotkin, M.

    1991-12-18

    The following topics are discussed on the Brookhaven electron analogue: L.J. Haworth and E.L. VanHorn letters; Original G.K. Green outline for report; General description; Parameter list; Mechanical Assembly; Alignment; Degaussing; Vacuum System; Injection System; The pulsed inflector; RF System; Ferrite Cavity; Pick-up electrodes and preamplifiers; Radio Frequency power amplifier; Lens supply; Controls and Power; and RF acceleration summary.

  18. Translational symmetry of high order tokamak flux surface shaping in gyrokinetics

    CERN Document Server

    Ball, Justin; Barnes, Michael

    2015-01-01

    A particular translational symmetry of the local nonlinear $\\delta f$ gyrokinetic model is demonstrated analytically and verified numerically. This symmetry shows that poloidally translating all the flux surface shaping effects with large poloidal mode number by a single tilt angle has an exponentially small effect on the transport properties of a tokamak. This is shown using a generalization of the Miller local equilibrium model to specify an arbitrary flux surface geometry. With this geometry specification we find that, when performing an expansion in large flux surface shaping mode number, the governing equations of gyrokinetics are symmetric in the poloidal translation of the high order shaping effects. This allows us to take the fluxes from a single configuration and calculate the fluxes in any configuration that can be produced by translating the large mode number shaping effects. This creates a distinction between tokamaks with mirror symmetric flux surfaces and tokamaks without mirror symmetry, which ...

  19. A high-flux BEC source for mobile atom interferometers

    CERN Document Server

    Rudolph, Jan; Grzeschik, Christoph; Sternke, Tammo; Grote, Alexander; Popp, Manuel; Becker, Dennis; Müntinga, Hauke; Ahlers, Holger; Peters, Achim; Lämmerzahl, Claus; Sengstock, Klaus; Gaaloul, Naceur; Ertmer, Wolfgang; Rasel, Ernst M

    2015-01-01

    Quantum sensors based on coherent matter-waves are precise measurement devices whose ultimate accuracy is achieved with Bose-Einstein condensates (BEC) in extended free fall. This is ideally realized in microgravity environments such as drop towers, ballistic rockets and space platforms. However, the transition from lab-based BEC machines to robust and mobile sources with comparable performance is a technological challenge. Here we report on the realization of a miniaturized setup, generating a flux of $4 \\times 10^5$ quantum degenerate $^{87}$Rb atoms every 1.6 s. Ensembles of $1 \\times 10^5$ atoms can be produced at a 1 Hz rate. This is achieved by loading a cold atomic beam directly into a multi-layer atom chip that is designed for efficient transfer from laser-cooled to magnetically trapped clouds. The attained flux of degenerate atoms is on par with current lab-based experiments while offering significantly higher repetition rates. The compact and robust design allows for mobile operation in a variety of...

  20. Examination of W7-X target elements after high heat flux testing

    International Nuclear Information System (INIS)

    The reception tests performed on the pre-series high heat flux elements of WENDELSTEIN 7-X (W7-X) divertor by means of infrared thermography inspection and high heat flux thermal cycling tests, exhibited some tiles with thermal inhomogenities, which developed during high heat flux testing. To assess damage detection and to understand the behaviour of pre-series elements under heat loading, post-testing investigations were undertaken to discriminate the tiles with insufficient bonding. Metallographic studies showed a good correlation with the surface temperature rise measured during the thermal cycling tests and the results of non destructive post-examination.

  1. Examples of utilizing high flux, high dose irradiation in activation analysis

    International Nuclear Information System (INIS)

    The science group of Kanazawa University has carried out the analysis of the main trace elements in meteorites and geochemically interesting rocks and minerals by the activation process using reactor neutrons, 14 MeV neutrons and 30 - 100 MeV bremsstrahlung. Also it has taken part in the international joint analysis of geochemical standard rock samples. As for a number of the samples among those, the high flux, high dose irradiation in the KUR core and the JMTR has been required, and the many objectives of activation analysis can be attained easily. In this report, why and in what case is the irradiation like this necessary is shown by examples. The meaning of activation analysis includes both the case of the assay of formed radionuclides and the case of the assay of rare gas isotopes by mass analysis among the cases of formed nuclides being stable. In most of the case of activation analysis, the assay of formed radionuclides is carried out by gamma ray spectrometry using (n, gamma) reaction, and high flux, high dose irradiation is required by specific reasons. In the analysis of trace elements by rare gas-forming nuclides, 40Ar/39Ar method in K-Ar age measurement is a well known example. Those examples are shown. (K.I.)

  2. Landmarks in particle physics at Brookhaven National Laboratory: Brookhaven Lecture Series, Number 238

    International Nuclear Information System (INIS)

    Robert Adair's lecture on Landmarks in Particle Physics at Brookhaven National Laboratory (BNL) is a commemoration of the 40th Anniversary of Brookhaven National Laboratory. Adair describes ten researches in elementary particle physics at Brookhaven that had a revolutionary impact on the understanding of elementary particles. Two of the discoveries were made in 1952 and 1956 at the Cosmotron, BNL's first proton accelerator. Four were made in 1962 and 1964 at the Alternating Gradient Synchrotron, the Cosmotron's replacement. Two other discoveries in 1954 and 1956 were theoretical, and strong focusing (1952) is the only technical discovery. One discovery (1958) happened in an old barrack. Four of the discoveries were awarded the Nobel prize in Physics. Adair believes that all of the discoveries are worthy of the Nobel prize. 14 figs

  3. Possibilities for relativistic heavy ion collisions at Brookhaven

    International Nuclear Information System (INIS)

    Since 1980 there has been considerable interest at Brookhaven in exploiting the existence of the Colliding Beam Accelerator, CBA, earlier referred to as Isabelle, for the generation of heavy ion collisions at very high energies. The only requirement for a heavy ion collider would have been for an energy booster for the Tandem accelerator and a tunnel and magnet transport system to the AGS. For a few million dollars heavy ions up to nearly 200 GeV/amu could be collided with luminosities of 1027 to 1028/cm2 sec in experimental halls with ideal facilities for heavy ion physics studies. Although the CBA project has been stopped, it is still true that Brookhaven has in place enormous advantages for constructing a heavy ion collider. This paper describes a design that exploits those advantages. It uses the tunnel and other civil construction, the refrigerator, vacuum equipment, injection line components, and the magnet design for which there is expertise and a production facility in place. The result is a machine that appears quite different than would a machine designed from first principles without access to these resources but one which is of high performance and of very attractive cost

  4. Statistical similarity between high energy charged particle fluxes in near-earth space and earthquakes

    Science.gov (United States)

    Wang, P.; Chang, Z.; Wang, H.; Lu, H.

    2014-05-01

    It has long been noticed that rapid short-term variations of high energy charged particle fluxes in near-Earth space occur more frequently several hours before the main shock of earthquakes. Physicists wish that this observation supply a possible precursor of strong earthquakes. Based on DEMETER data, we investigate statistical behaviors of flux fluctuations for high energy charged particles in near-Earth space. Long-term clustering, scaling, and universality in the temporal occurrence are found. There is high degree statistical similarity between high energy charged particle fluxes in near-Earth space and earthquakes. Thus, the observations of the high energy particle fluxes in near-Earth space may supply a useful tool in the study of earthquakes.

  5. Nanostructures and pinholes on W surfaces exposed to high flux D plasma at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Y.Z., E-mail: jaja880816@aliyun.com [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, W., E-mail: liuw@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Xu, B. [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Luo, G.-N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Li, C.; Fu, B.Q. [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); De Temmerman, G. [FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Edisonbaan 14, 3439 MN Nieuwegein (Netherlands); ITER Organization, Route de Vinon-Sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France)

    2015-08-15

    Nanostructures and pinholes formed on tungsten surface exposed to high fluxes (10{sup 24} m{sup −2} s{sup −1}) deuterium ions at 943 K and 1073 K were studied by scanning electron microscopy and electron backscatter diffraction. Nanostructure formation is observed at 943 K and 1073 K, and exhibits a strong dependence on the surface orientation. With increasing fluence, pinholes appear on the surface and are mainly observed on grains with surface normal near [1 1 1]. The pinholes are speculated to be caused by the rupture of bubbles formed near the surface. The formation of pinholes has no obvious relationship with the surface nanostructures.

  6. RELAP5/MOD2.5 analysis of the HFBR [High Flux Beam Reactor] for a loss of power and coolant accident

    International Nuclear Information System (INIS)

    A set of postulated accidents were evaluated for the High Flux Beam Reactor (HFBR) at Brookhaven National Laboratory. A loss of power accident (LOPA) and a loss of coolant accident (LOCA) were analyzed. This work was performed in response to a DOE review that wanted to update the understanding of the thermal hydraulic behavior of the HFBR during these transients. These calculations were used to determine the margins to fuel damage at the 60 MW power level. The LOPA assumes all the backup power systems fail (although this event is highly unlikely). The reactor scrams, the depressurization valve opens, and the pumps coast down. The HFBR has down flow through the core during normal operation. To avoid fuel damage, the core normally goes through an extended period of forced down flow after a scram before natural circulation is allowed. During a LOPA, the core will go into flow reversal once the buoyancy forces are larger than the friction forces produced during the pump coast down. The flow will stagnate, reverse direction, and establish a buoyancy driven (natural circulation) flow around the core. Fuel damage would probably occur if the critical heat flux (CHF) limit is reached during the flow reversal event. The RELAP5/MOD2.5 code, with an option for heavy water, was used to model the HFBR and perform the LOPA calculation. The code was used to predict the time when the buoyancy forces overcome the friction forces and produce upward directed flow in the core. The Monde CHF correlation and experimental data taken for the HFBR during the design verification phase in 1963 were used to determine the fuel damage margin. 20 refs., 40 figs., 11 tabs

  7. Temperature measurements during high flux ion beam irradiations.

    Science.gov (United States)

    Crespillo, M L; Graham, J T; Zhang, Y; Weber, W J

    2016-02-01

    A systematic study of the ion beam heating effect was performed in a temperature range of -170 to 900 °C using a 10 MeV Au(3+) ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 10(12) cm(-2) s(-1). Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggests that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. A simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beam analysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect. PMID:26931879

  8. Temperature measurements during high flux ion beam irradiations

    Science.gov (United States)

    Crespillo, M. L.; Graham, J. T.; Zhang, Y.; Weber, W. J.

    2016-02-01

    A systematic study of the ion beam heating effect was performed in a temperature range of -170 to 900 °C using a 10 MeV Au3+ ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 1012 cm-2 s-1. Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggests that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. A simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beam analysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect.

  9. Properties of High Basicity Mold Fluxes for Peritectic Steel Slab Casting

    Institute of Scientific and Technical Information of China (English)

    LONG Xiao; HE Sheng-ping; XU Jian-fei; HUO Xu-ling; WANG Qian

    2012-01-01

    In high speed continuous casting of peritectic steel slabs, mold fluxes with high basicity are required for less surface defect product. However, the basicity of remaining liquid slag film tends to decrease in casting process because of the crystallization of 3CaO ·2SiO2 · CaF2. Thus, a way is put forward to improve mold fluxesr properties by raising the original basicity. In order to confirm the possibility of this method, the effect of rising original basicity on the properties of mold fluxes is discussed. Properties of high fluorine based mold fluxes with different basicities and contents of CaF2 , Na2 O, and MgO were measured, respectively. Then, properties of higher basicity mold fluxes were discussed and compared with traditional ones. The results show that increasing the basicity index can improve the melting and flow property of mold fluxes. With the increasing basicity, crystallization rate of mold fluxes increases obviously and crystallization temperature tends to decrease when the basicity exceeds 1.35. The method presen- ted before is proved as a potential way to resolve the contradiction between horizontal heat transfer controlling and solidified shell lubricating for peritectic steel slab casting. But further study on improving the flow property of liquid slag is needed. This work can be used to guide mold fluxes design for high speed continuous casting of peritectic steel slabs.

  10. Brookhaven National Laboratory site environmental report for calendar year 1994

    Energy Technology Data Exchange (ETDEWEB)

    Naidu, J.R.; Royce, B.A. [eds.

    1995-05-01

    This report documents the results of the Environmental Monitoring Program at Brookhaven National Laboratory and presents summary information about environmental compliance for 1994. To evaluate the effect of Brookhaven National Laboratory`s operations on the local environment, measurements of direct radiation, and a variety of radionuclides and chemical compounds in ambient air, soil, sewage effluent, surface water, groundwater, fauna and vegetation were made at the Brookhaven National Laboratory site and at sites adjacent to the Laboratory.

  11. Brookhaven National Laboratory site environmental report for calendar year 1994

    International Nuclear Information System (INIS)

    This report documents the results of the Environmental Monitoring Program at Brookhaven National Laboratory and presents summary information about environmental compliance for 1994. To evaluate the effect of Brookhaven National Laboratory's operations on the local environment, measurements of direct radiation, and a variety of radionuclides and chemical compounds in ambient air, soil, sewage effluent, surface water, groundwater, fauna and vegetation were made at the Brookhaven National Laboratory site and at sites adjacent to the Laboratory

  12. Overview of irradiation facilities and experiments currently in the Oak Ridge High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    The Oak Ridge High Flux Isotope Reactor (HFIR) is an 85 MW research reactor with a variety of irradiation facilities. The target region has the highest continuous thermal neutron flux available in the western world and facilities in the beryllium reflector provide opportunities to irradiate experiments of various sizes in a variety of neutron spectrums. Major programs utilizing these facilities include Fusion Materials, Advanced Neutron Source (ANS), New Production Reactor, and Modular High Temperature Gas-Cooled Reactor

  13. Plasma resonance and flux dynamics in layered high-Tc superconductors

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Sakai, S.

    2000-01-01

    Flux dynamics of layered high Tc superconductors are considered with special emphasis on the small oscillation modes. In particular we find the dispersion relation for the plasma modes and discuss the spectra to be observed in microwave experiments.......Flux dynamics of layered high Tc superconductors are considered with special emphasis on the small oscillation modes. In particular we find the dispersion relation for the plasma modes and discuss the spectra to be observed in microwave experiments....

  14. COMPARISON OF COOLING SCHEMES FOR HIGH HEAT FLUX COMPONENTS COOLING IN FUSION REACTORS

    Directory of Open Access Journals (Sweden)

    Phani Kumar Domalapally

    2015-04-01

    Full Text Available Some components of the fusion reactor receives high heat fluxes either during the startup and shutdown or during the operation of the machine. This paper analyzes different ways of enhancing heat transfer using helium and water for cooling of these high heat flux components and then conclusions are drawn to decide the best choice of coolant, for usage in near and long term applications.

  15. Brookhaven highlights, October 1, 1989--September 30, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.S.; Cohen, A.; Greenberg, D.; Seubert, L.; Kuper, J.B.H. (eds.)

    1990-01-01

    This report discusses research being conducted at Brookhaven National Laboratory. Highlights from all the department are illustrated. The main topics are on accelerator development and applications. (LSP)

  16. A neutronic feasibility study for LEU conversion of the Brookhaven Medical Research Reactor (BMRR)

    International Nuclear Information System (INIS)

    A neutronic feasibility study for converting the Brookhaven Medical Research Reactor from HEU to LEU fuel was performed at Argonne National Laboratory in cooperation with Brookhaven National Laboratory. Two possible LEU cores were identified that would provide nearly the same neutron flux and spectrum as the present HEU core at irradiation facilities that are used for Boron Neutron Capture Therapy and for animal research. One core has 17 and the other has 18 LEU MTR-type fuel assemblies with uranium densities of 2.5g U/cm3 or less in the fuel meat. This LEU fuel is fully-qualified for routine use. Thermal hydraulics and safety analyses need to be performed to complete the feasibility study. (author)

  17. Polarization in inclusive production at Brookhaven

    International Nuclear Information System (INIS)

    At Brookhaven, Λ's are produced polarized in p-p interactions perpendicular to a horizontal production plane defined by proton-unit vector x Λ-unit vector with their spins pointing down roughly twice as often as up, for a 1 GeV/c transverse Λ momentum. Such a large effect must indicate a simplicity in the underlying dynamics of particle production, even at low transverse momentum. Four BNL experiments are discussed in the context of experiments done at other energies with respect to present (lack of) understanding of the origin of the effect. 3 figures

  18. Transverse beam dampers for the Brookhaven AGS

    International Nuclear Information System (INIS)

    A wide band damper system has been developed for the Brookhaven Alternating Gradient Synchrotron (AGS). The system consists of two sets of PUE pickups, analog and digital processing electronics, four 500 Watt wide band power amplifiers, and two pairs of strip line deflectors. The system is currently used to damp transverse coherent instabilities and injection errors, in both planes, for protons and all species of Heavy Ions. This paper discusses the system design and operation, focusing on the engineering considerations and problems encountered in the actual implementation. Operational data from both protons and Heavy Ion beams is presented

  19. Control of Crystal Morphology for Mold Flux During High-Aluminum AHSS Continuous Casting Process

    Science.gov (United States)

    GUO, Jing; SEO, Myung-Duk; SHI, Cheng-Bin; CHO, Jung-Wook; KIM, Seon-Hyo

    2016-05-01

    In the present manuscript, the efforts to control the crystal morphology are carried out aiming at improving the lubrication of lime-alumina-based mold flux for casting advanced high-strength steel with high aluminum. Jackson α factors for crystals of melt crystallization in multi-component mold fluxes are established and reasonably evaluated by applying thermodynamic databases to understand the crystal morphology control both in lime-alumina-based and lime-silica-based mold fluxes. The results show that Jackson α factor and supercooling are the most critical factors to determine the crystal morphology in a mold flux. Crystals precipitating in mold fluxes appear with different morphologies due to their different Jackson α factors and are likely to be more faceted with higher Jackson α factor. In addition, there is a critical supercooling degree for crystal morphology dendritic transition. When the supercooling over the critical value, the crystals transform from faceted shape to dendritic ones in morphology as the kinetic roughening occurs. Typically, the critical supercooling degrees for cuspidine dendritic transition in the lime-silica-based mold fluxes are evaluated to be between 0.05 and 0.06. Finally, addition of a small amount of Li2O in the mold flux can increase the Jackson α factor and decrease the supercooling for cuspidine precipitation; thus, it is favorable to enhance a faceted cuspidine crystal.

  20. Fractal Pattern Growth in Ti-Implanted Steel with High Ion Flux

    Institute of Scientific and Technical Information of China (English)

    张通和; 吴瑜光; 刘安东

    2002-01-01

    We report on the formation of metal nanometre phase and fractal patterns in steel using metal vapour vacuum arc source ion implantation with high ion flux. The dense nanometre phases are cylindrical and well dispersed in the Ti-implanted layer with an ion flux up to 50μA/cm2. The collision fractal pattern is formed in Ti-implanted steel with an ion flux of 25μA/cm2 and the disconnected fractal pattern is observed with an ion flux of 50μA/cm2.The average density ofnanometre phases decreases from 1.2 × 1011/cm2 to 6.5 × 1010/cm2 as the ion flux increases from 25 μA/cm2 to 50 μA/cm2. Fractal pattern growth is in remarkable agreement with Sander's diffusion-limited aggregation model. The alloy clusters have diffused and aggregated in chains forming branches to grow a beautiful tree during Ti implantation with an ion flux ranging from 75μA/cm2 to 85μA/cm2. We discuss the model of fractal pattern growth during ion implantation with high ion flux.

  1. Effect of fluxes on high iron and low silica sintering

    Institute of Scientific and Technical Information of China (English)

    ZHU De-qing(朱德庆); ZHANG Ke-cheng(张克诚); PAN Jian(潘建); FAN Xiao-hui(范晓慧); HU You-ming(胡友名); John Clout

    2003-01-01

    Burnt lime and serpentine were incorporated into the sinter mix to improve high iron and low silica sinte-ring. Optimization of how to use burnt lime including dosage of burnt lime, moisture of sinter mix, hydrating andgranulation time was performed. Evaluations of sinter characteristics including sinter mineralogy, reducibility, lowtemperature reduction degradation, softening and melting down properties were carried out. Compared with the re-sults of traditional process in base case, the tumbling index (TI) is increased by 1.53%-2.33% through proportio-ning high ratio of burnt lime or adding serpentine in the sinter mix. It is shown that effective granulation, better per-meability and improved high temperature reactivity in the sinter bed are achieved, resulting in an increase in 3.13 %- 5.10% calcium ferrite occurring in acicular and columnar shape and decrease in glass phase, and with the reduc-ibility index(RI) being increased by 1.65%- 3.25%.

  2. A note on the general multi-moment constrained flux reconstruction formulation for high order schemes

    CERN Document Server

    Xiao, Feng; Chen, Chungang; Li, Xingliang

    2012-01-01

    This paper presents a general formulation to construct high order numerical schemes by using multi-moment constraint conditions on the flux function reconstruction. The new formulation, so called multi-moment constrained flux reconstruction (MMC-FR), distinguishes itself essentially from the flux reconstruction formulation (FR) of Huynh (2007) by imposing not only the continuity constraint conditions on the flux function at the cell boundary, but also other types constraints which may include those on the spatial derivatives or the point values. This formulation can be also interprated as a blend of Lagrange interpolation the Hermite interpolation, which provides a numerical framework to accomodate a wider spectrum of high order schemes. Some representative schemes will be presented and evaluated through Fourier analysis and numerical tests.

  3. The Flux Variability of Markarian 501 in Very High Energy Gamma Rays

    International Nuclear Information System (INIS)

    The BL Lacertae object Markarian 501 was identified as a source of γ-ray emission at the Whipple Observatory in 1995 March. Here we present a flux variability analysis on several timescales of the 233 hr data set accumulated over 213 nights (from March 1995 to July 1998) with the Whipple Observatory 10 m atmospheric Cerenkov imaging telescope. In 1995, with the exception of a single night, the flux from Markarian 501 was constant on daily and monthly timescales and had an average flux of only 10% that of the Crab Nebula, making it the weakest very high energy source detected to date. In 1996, the average flux was approximately twice the 1995 flux and showed significant month-to-month variability. No significant day-scale variations were detected. The average γ-ray flux above ∼350 GeV in the 1997 observing season rose to 1.4 times that of the Crab Nebula 14 times the 1995 discovery level allowing a search for variability on timescales shorter than 1 day. Significant hour-scale variability was present in the 1997 data, with the shortest, observed on MJD 50,607, having a doubling time of ∼2 hr. In 1998 the average emission level decreased considerably from that of 1997 (to ∼20% of the Crab Nebula flux), but two significant flaring events were observed. Thus the emission from Markarian 501 shows large amplitude and rapid flux variability at very high energies, as does Markarian 421. It also shows large mean flux level variations on year-to-year timescales, behavior that has not been seen from Markarian 421 so far. copyright copyright 1999. The American Astronomical Society

  4. The Flux Variability of Markarian 501 in Very High Energy Gamma Rays

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, J. (Fred Lawrence Whipple Observatory, Harvard-Smithsonian CfA, P.O. Box 97, Amado, AZ 85645-0097 (United States) Dept. of Experimental Physics, University College, Belfield, Dublin 4 (Ireland)); Bond, I.H. (Department of Physics, University of Leeds, Leeds, LS2 9JT, West Yorkshire, England (United Kingdom)); Boyle, P.J. (Department of Experimental Physics, University College, Belfield, Dublin 4 (Ireland)); Bradbury, S.M. (Department of Physics, University of Leeds, Leeds, LS2 9JT, West Yorkshire, England (United Kingdom)); Breslin, A.C. (Department of Experimental Physics, University College, Belfield, Dublin 4 (Ireland)); Buckley, J.H. (Department of Physics, Washington University, St. Louis, MO 63130 (United States)); Burdett, A.M. (Fred Lawrence Whipple Observatory, Harvard-Smithsonian CfA, P.O. Box 97, Amado, AZ 85645-0097 (United States) Department of Physics, University of Leeds, Leeds, LS2 9JT, West Yorkshire, England (United Kingdom)); Gordo, J.B. (Department of

    1999-06-01

    The BL Lacertae object Markarian 501 was identified as a source of [gamma]-ray emission at the Whipple Observatory in 1995 March. Here we present a flux variability analysis on several timescales of the 233 hr data set accumulated over 213 nights (from March 1995 to July 1998) with the Whipple Observatory 10 m atmospheric Cerenkov imaging telescope. In 1995, with the exception of a single night, the flux from Markarian 501 was constant on daily and monthly timescales and had an average flux of only 10[percent] that of the Crab Nebula, making it the weakest very high energy source detected to date. In 1996, the average flux was approximately twice the 1995 flux and showed significant month-to-month variability. No significant day-scale variations were detected. The average [gamma]-ray flux above [approximately]350 GeV in the 1997 observing season rose to 1.4 times that of the Crab Nebula[emdash]14 times the 1995 discovery level[emdash]allowing a search for variability on timescales shorter than 1 day. Significant hour-scale variability was present in the 1997 data, with the shortest, observed on MJD 50,607, having a doubling time of [approximately]2 hr. In 1998 the average emission level decreased considerably from that of 1997 (to [approximately]20[percent] of the Crab Nebula flux), but two significant flaring events were observed. Thus the emission from Markarian 501 shows large amplitude and rapid flux variability at very high energies, as does Markarian 421. It also shows large mean flux level variations on year-to-year timescales, behavior that has not been seen from Markarian 421 so far. [copyright] [ital [copyright] 1999.] [ital The American Astronomical Society

  5. Behavior of TPC`s in a high particle flux environment

    Energy Technology Data Exchange (ETDEWEB)

    Etkin, A.; Eiseman, S.E.; Foley, K.J.; Hackenburg, R.W.; Longacre, R.S.; Love, W.A.; Morris, T.W.; Platner, E.D.; Saulys, A.C.; Lindenbaum, S.J. [Brookhaven National Lab., Upton, NY (United States); Chan, C.S.; Kramer, M.A.; Zhao, K.H.; Zhu, Y. [City College of New York, New York (United States); Hallman, T.J.; Madansky, L. [Johns Hopkins Univ., Baltimore, MD (United States); Ahmad, S.; Bonner, B.E.; Buchanan, J.A.; Chiou, C.N.; Clement, J.M.; Mutchler, G.S.; Roberts, J.B. [Bonner Nuclear Lab., Houston, TX (United States)

    1991-12-31

    TPC`s (Time Projection Chamber) used in E-810 at the TAGS (Alternating Gradient Synchrotron) were exposed to fluxes equivalent to more than 10 minimum ionizing particles per second to find if such high fluxes cause gain changes or distortions of the electric field. Initial results of these and other tests are presented and the consequences for the RHIC (Relativistic Heavy Ion Collider) TPC-based experiments are discussed.

  6. Construction of Locally Conservative Fluxes for High Order Continuous Galerkin Finite Element Methods

    OpenAIRE

    Deng, Quanling; Ginting, Victor

    2016-01-01

    We propose a simple post-processing technique for linear and high order continuous Galerkin Finite Element Methods (CGFEMs) to obtain locally conservative flux field. The post-processing technique requires solving an auxiliary problem on each element independently which results in solving a linear algebra system whose size is low for any order CGFEM. The post-processing could have been done directly from the finite element solution that results in locally conservative flux on the element. How...

  7. Growth of a dry spot under a vapor bubble at high heat flux and high pressure

    CERN Document Server

    Nikolayev, Vadim; Lagier, G -L; Hegseth, J

    2016-01-01

    We report a 2D modeling of the thermal diffusion-controlled growth of a vapor bubble attached to a heating surface during saturated boiling. The heat conduction problem is solved in a liquid that surrounds a bubble with a free boundary and in a semi-infinite solid heater by the boundary element method. At high system pressure the bubble is assumed to grow slowly, its shape being defined by the surface tension and the vapor recoil force, a force coming from the liquid evaporating into the bubble. It is shown that at some typical time the dry spot under the bubble begins to grow rapidly under the action of the vapor recoil. Such a bubble can eventually spread into a vapor film that can separate the liquid from the heater thus triggering the boiling crisis (critical heat flux).

  8. Evaporation at microscopic scale and at high heat flux

    International Nuclear Information System (INIS)

    This thesis theoretically investigates the transport processes in the vicinity of the triple gas-liquid-solid contact line and its impact on macroscopic evaporation. In the first part of the thesis, the hydrodynamics close to the contact line at partial wetting is studied. Specifically, evaporation into the atmosphere of pure vapor driven by heating of the substrate is considered. The question of singularity relaxation is addressed. The main finding of the thesis is that the Kelvin effect (dependence of saturation temperature on pressure) is sufficient by itself to relax the hydrodynamic contact line singularity. The proposed microregion (the contact line vicinity) model for small interface slopes is solved numerically. Asymptotic solutions are found for some specific cases. The governing length scales of the problem are identified and the multi-scale nature of the phenomenon is addressed. Parametric studies revealing the role of the thermal resistance of vapor-liquid interface, slip length, thermo-capillary term, the vapor recoil and surface forces are also performed. An extension of the lubrication approximation for high slopes of the gas-liquid interface at evaporation is discussed. In the second part of the thesis, the previously established microregion model is coupled to a simplified single vapor bubble growth numerical simulation. The bubble departure from the heater at boiling is also studied. It was proposed in the thesis, that under high heat loads, the increase of the apparent contact angle causes the vapor bubble to spread over the heated substrate. Such a behavior may cause the heater dry-out that occurs during the boiling crisis. (author)

  9. Methods to assess high-resolution subsurface gas concentrations and gas fluxes in wetland ecosystems

    DEFF Research Database (Denmark)

    Elberling, Bo; Kühl, Michael; Glud, Ronnie N.;

    2013-01-01

    wetland and peat soils are highly heterogeneous, containing a mosaic of dynamic macropore systems created by both macrofauna and flora leading to distinct spatial and temporal variations in gas concentration on a scale of millimeters and minutes. Applications of these new methodologies allow measurements......The need for measurements of soil gas concentrations and surface fluxes of greenhouse gases at high temporal and spatial resolution in wetland ecosystem has lead to the introduction of several new analytical techniques and methods. In addition to the automated flux chamber methodology for high......-resolution estimates of greenhouse gas fluxes across the soil-atmosphere interface, these high-resolution methods include microsensors for quantification of spatiotemporal concentration dynamics in O2 and N2O at micrometer scales, fiber-optic optodes for long-term continuous point measurements of O2 concentrations...

  10. Investigation of high flux test module for the international fusion materials irradiation facilities (IFMIF)

    International Nuclear Information System (INIS)

    This report describes investigation on structure of a high neutron flux test module (HFTM) for the International Fusion Materials Irradiation Facilities (IFMIF). The HFTM is aimed for neutron irradiation of a specimen in a high neutron flux domain of the test cell for irradiation ground of IFMIF. We investigated the overall structure of the HFTM that was able to include specimens in a rig and thermocouple arrangement, an interface of control signal and support structure. Moreover, pressure and the amount of the bend in the module vessel (a rectangular section pressure vessel) were calculated. The module vessel did a rectangular section from limitation of a high neutron flux domain. Also, we investigated damage of thermocouples under neutron irradiation, which was a temperature sensor of irradiation materials temperature control demanded high precision. Based on these results, drawings on the HTFM structure. (author)

  11. A conceptual high flux reactor design with scope for use in ADS applications

    Indian Academy of Sciences (India)

    Usha Pal; V Jagannathan

    2007-02-01

    A 100 MWt reactor design has been conceived to support flux level of the order of 1015 n/cm2/s in selected flux trap zones. The physics design considers high enriched metallic alloy fuel in the form of annular plates placed in a D2O moderator tank in a hexagonal lattice arrangement. By choosing a tight lattice pitch in the central region and double the lattice pitch in the outer region, it is possible to have both high fast flux and thermal flux trap zones. By design the flux level in the seed fuel has been kept lower than in the high flux trap zones so that the burning rate of the seed is reduced. Another important objective of the design is to maximize the time interval of refueling. As against a typical refueling interval of a few weeks in such high flux reactor cores, it is desired to maximize this period to as much as six months or even one year. This is possible to achieve by eliminating the conventional control absorbers and replacing them with a suitable amount of fertile material loading in the reactor. Requisite number of seedless thorium–aluminum alloy plates are placed at regular lattice locations vacated by seed fuel in alternate fuel layers. It is seen that these thorium plates are capable of acquiring asymptotic fissile content of 14 g/kg in about 100 days of irradiation at a flux level of 8 × 1014 n/cm2 /s. In summary, the core has a relatively higher fast flux in the central region and high thermal flux in the outer region. The present physics design envisages a flat core excess reactivity for the longest possible cycle length of 6 months to one year. It is also possible to modify the design for constant subcriticality for about the same period or longer duration by considering neutron spallation source at the centre and curtailing the power density in the inner core region by shielding it with a layer of thoria fuel loading.

  12. Digital transverse beam dampers from the Brookhaven AGS

    International Nuclear Information System (INIS)

    A wide band, digital damper system has been developed and is in use at the Brookhaven Alternating Gradient Synchrotron (AGS). The system consists of vertical and horizontal capacitive pickups, analog and digital processing electronics, four 500 Watt wide band power amplifiers, and two pairs of strip line beam kickers. The system is currently used to damp transverse coherent instabilities and injection errors, in both planes, for protons and all species of heavy ions. This paper discusses the system design and operation, particularly with regard to stabilization of the high intensity proton beam. The analog and digital signal processing techniques used to achieve optimum results are discussed. Operational data showing the effect of the damping are presented

  13. First experiences with a fastbus system at Brookhaven

    International Nuclear Information System (INIS)

    A new concept in high energy data acquisition systems called Fastbus has been developed and implemented at Brookhaven. The system which is capable of sub-gigabit/sec speeds has been operating for some time now. A number of modules including an on-bus processor, a PDP11 interface, 32 channel coincidence latches, a 16 channel scaler, a 32 channel μ-clock device, a 60 nsec memory and a predetermined time module have been developed and built. Features of the system include extensive use of ECL logic and a water cooled crate with conduction heat transfer within a module. The system is used in an on-line experiment at the AGS. Operating experience will be discussed

  14. High isoprenoid flux Escherichia coli as a host for carotenoids production.

    Science.gov (United States)

    Suh, Wonchul

    2012-01-01

    A noncarotenogenic microbe E. coli was engineered for high production of carotenoids. To increase the isoprenoid flux, the chromosomal native promoters of the rate-controlling steps (dxs, idi and ispDispF) in the isoprenoid pathway were replaced with a strong bacteriophage T5 promoter (P(T5)) by using the λ-Red recombinase system in combination with the Flp/FRT site-specific recombination system for marker excision and P1 transduction for gene trait stacking. The resulting high isoprenoid flux E. coli can be used as a starting strain to produce various carotenoids by introducing heterologous carotenoid genes. In this study, the high isoprenoid flux E. coli was transformed with a plasmid carrying the β-carotene biosynthetic genes from Pantoea stewartii for β-carotene production. PMID:22144352

  15. Modeling high-energy cosmic ray induced terrestrial and atmospheric neutron flux: A lookup table

    CERN Document Server

    Overholt, Andrew; Atri, Dimitra

    2013-01-01

    Under current conditions, the cosmic ray spectrum incident on the Earth is dominated by particles with energies < 1 GeV. Astrophysical sources including high energy solar flares, supernovae and gamma ray bursts produce high energy cosmic rays (HECRs) with drastically higher energies. The Earth is likely episodically exposed to a greatly increased HECR flux from such events, some of which lasting thousands to millions of years. The air showers produced by HECRs ionize the atmosphere and produce harmful secondary particles such as muons and neutrons. Neutrons currently contribute a significant radiation dose at commercial passenger airplane altitude. With higher cosmic ray energies, these effects will be propagated to ground level. This work shows the results of Monte Carlo simulations quantifying the neutron flux due to high energy cosmic rays at various primary energies and altitudes. We provide here lookup tables that can be used to determine neutron fluxes from primaries with total energies 1 GeV - 1 PeV...

  16. The Influence of Non-Uniform High Heat Flux on Thermal Stress of Thermoelectric Power Generator

    Directory of Open Access Journals (Sweden)

    Tingzhen Ming

    2015-11-01

    Full Text Available A thermoelectric generator (TEG device which uses solar energy as heat source would achieve higher efficiency if there is a higher temperature difference between the hot-cold ends. However, higher temperature or higher heat flux being imposed upon the hot end will cause strong thermal stress, which will have a negative influence on the life cycle of the thermoelectric module. Meanwhile, in order to get high heat flux, a Fresnel lens is required to concentrate solar energy, which will cause non-uniformity of heat flux on the hot end of the TEG and further influence the thermal stress of the device. This phenomenon is very common in solar TEG devices but seldom research work has been reported. In this paper, numerical analysis on the heat transfer and thermal stress performance of a TEG module has been performed considering the variation on the power of the heat flux being imposed upon the hot-end; the influence of non-uniform high heat flux on thermal stress has also been analyzed. It is found that non-uniformity of high heat flux being imposed upon the hot end has a significant effect on the thermal stress of TEG and life expectation of the device. Taking the uniformity of 100% as standard, when the heating uniformity is 70%, 50%, 30%, and 10%, respectively, the maximum thermal stress of TEG module increased by 3%, 6%, 12%, and 22% respectively. If we increase the heat flux on the hot end, the influence of non-uniformity on the thermal stress will be more remarkable.

  17. Poloidal tilting symmetry of high order tokamak flux surface shaping in gyrokinetics

    Science.gov (United States)

    Ball, Justin; Parra, Felix I.; Barnes, Michael

    2016-04-01

    A poloidal tilting symmetry of the local nonlinear δ f gyrokinetic model is demonstrated analytically and verified numerically. This symmetry shows that poloidally rotating all the flux surface shaping effects with large poloidal mode number by a single tilt angle has an exponentially small effect on the transport properties of a tokamak. This is shown using a generalization of the Miller local equilibrium model to specify an arbitrary flux surface geometry. With this geometry specification we find that, when performing an expansion in large flux surface shaping mode number, the governing equations of gyrokinetics are symmetric in the poloidal tilt of the high order shaping effects. This allows us to take the fluxes from a single configuration and calculate the fluxes in any configuration that can be produced by tilting the large mode number shaping effects. This creates a distinction between tokamaks with mirror symmetric flux surfaces and tokamaks without mirror symmetry, which is expected to have important consequences for generating toroidal rotation using up-down asymmetry.

  18. High geothermal heat flux measured below the West Antarctic Ice Sheet.

    Science.gov (United States)

    Fisher, Andrew T; Mankoff, Kenneth D; Tulaczyk, Slawek M; Tyler, Scott W; Foley, Neil

    2015-07-01

    The geothermal heat flux is a critical thermal boundary condition that influences the melting, flow, and mass balance of ice sheets, but measurements of this parameter are difficult to make in ice-covered regions. We report the first direct measurement of geothermal heat flux into the base of the West Antarctic Ice Sheet (WAIS), below Subglacial Lake Whillans, determined from the thermal gradient and the thermal conductivity of sediment under the lake. The heat flux at this site is 285 ± 80 mW/m(2), significantly higher than the continental and regional averages estimated for this site using regional geophysical and glaciological models. Independent temperature measurements in the ice indicate an upward heat flux through the WAIS of 105 ± 13 mW/m(2). The difference between these heat flux values could contribute to basal melting and/or be advected from Subglacial Lake Whillans by flowing water. The high geothermal heat flux may help to explain why ice streams and subglacial lakes are so abundant and dynamic in this region. PMID:26601210

  19. Fractal pattern growth in Ti-implanted steel with high ion flux

    CERN Document Server

    Zhang Ton Ghe; Liu An Dong

    2002-01-01

    The author report on the formation of metal nano-metre phase and fractal patterns in steel using metal vapour vacuum arc source ion implantation with high ion flux. The dense nano-metre phases are cylindrical and well dispersed in the Ti-implanted layer with an ion flux up to 50 mu A/cm sup 2. The collision fractal pattern is formed in Ti-implanted steel with an ion flux of 25 mu A/cm sup 2 and the disconnected fractal pattern is observed with an ion flux of 50 mu A/cm sup 2. The average density of nano-metre phases decreases from 1.2 x 10 sup 1 sup 1 /cm sup 2 to 6.5 x 10 sup 1 sup 0 /cm sup 2 as the ion flux increases from 25 mu A/cm sup 2 to 50 mu A/cm sup 2. Fractal pattern growth is in remarkable agreement with Sander's diffusion-limited aggregation model. The alloy clusters have diffused and aggregated in chains forming branches to grow a beautiful tree during Ti implantation with an ion flux ranging from 75 mu A/cm sup 2 to 85 mu A/cm sup 2. The authors discuss the model of fractal pattern growth durin...

  20. Final report of the HFIR [High Flux Isotope Reactor] irradiation facilities improvement project

    International Nuclear Information System (INIS)

    The High-Flux Isotope Reactor (HFIR) has outstanding neutronics characteristics for materials irradiation, but some relatively minor aspects of its mechanical design severely limited its usefulness for that purpose. In particular, though the flux trap region in the center of the annular fuel elements has a very high neutron flux, it had no provision for instrumentation access to irradiation capsules. The irradiation positions in the beryllium reflector outside the fuel elements also have a high flux; however, although instrumented, they were too small and too few to replace the facilities of a materials testing reactor. To address these drawbacks, the HFIR Irradiation Facilities Improvement Project consisted of modifications to the reactor vessel cover, internal structures, and reflector. Two instrumented facilities were provided in the flux trap region, and the number of materials irradiation positions in the removable beryllium (RB) was increased from four to eight, each with almost twice the available experimental space of the previous ones. The instrumented target facilities were completed in August 1986, and the RB facilities were completed in June 1987

  1. How Big Science Came to Long Island: the Birth of Brookhaven Lab (429th Brookhaven Lecture)

    International Nuclear Information System (INIS)

    Robert P. Crease, historian for the U.S. Department of Energy's Brookhaven National Laboratory and Chair of the Philosophy Department at Stony Brook University, will give two talks on the Laboratory's history on October 31 and December 12. Crease's October 31 talk, titled 'How Big Science Came to Long Island: The Birth of Brookhaven Lab,' will cover the founding of the Laboratory soon after World War II as a peacetime facility to construct and maintain basic research facilities, such as nuclear reactors and particle accelerators, that were too large for single institutions to build and operate. He will discuss the key figures involved in starting the Laboratory, including Nobel laureates I.I. Rabi and Norman Ramsey, as well as Donald Dexter Van Slyke, one of the most renowned medical researchers in American history. Crease also will focus on the many problems that had to be overcome in creating the Laboratory and designing its first big machines, as well as the evolving relations of the Laboratory with the surrounding Long Island community and news media. Throughout his talk, Crease will tell fascinating stories about Brookhaven's scientists and their research.

  2. Magnetic control of laser ablation plasma for high-flux ion injectors

    International Nuclear Information System (INIS)

    We investigated the interaction of a laser ablation plasma with a longitudinal magnetic field aiming to create a directionally moving plasma for high-flux and low-emittance ion injectors. To study the plasma dynamics, time-of-flight measurements and energy analysis of the plasma ion flux were made as functions of the laser intensity and the magnetic field. Moderate magnetic field (∼0.2T) directed the fast and highly charged ions in the target normal. In addition, a slow peak appeared and increased with increasing the magnetic field. These results indicated that directional electric field is formed and recombination increases by the application of longitudinal magnetic field

  3. Microwave testing of high-Tc based direct current to a single flux quantum converter

    DEFF Research Database (Denmark)

    Kaplunenko, V. K.; Fischer, Gerd Michael; Ivanov, Z. G.;

    1994-01-01

    Design, simulation, and experimental investigations of a direct current to a single flux quantum converter loaded with a Josephson transmission line and driven by an external 70 GHz microwave oscillator are reported. The test circuit includes nine YBaCuO Josephson junctions aligned on the grain...... boundary of a 0°–32° asymmetric Y-ZrO2 bicrystal substrate. The performance of such converters is important for the development of the fast Josephson samplers required for testing of high-Tc rapid single flux quantum circuits in high-speed digital superconducting electronics. Journal of Applied Physics is...

  4. Research and development of metallic materials for plasma facing and high heat flux components

    International Nuclear Information System (INIS)

    This is a report of the meeting on research and developments of high Z metallic materials for plasma facing and high heat flux components, held at NIFS on March 8, 1994. Recent progress in research and developments of high Z metallic materials for plasma facing and high heat flux components is summarized. The following eight topics are included: 1) Recent experiment using high Z metals as plasma facing materials, 2) High Z divertor in helical system, 3) Hydrogen ion irradiation of tungsten, 4) Helium ion bombardment of molybdenum, 5) Thermal shock experiment of molybdenum, 6) Recent progress in fabrication of high Z materials, 7) Mechanical properties of molybdenum, 8) Neutron irradiation damage of molybdenum. (author)

  5. SPring-8 BL41XU, a high-flux macromolecular crystallography beamline

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Kazuya [SPring-8/JASRI, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Shimizu, Nobutaka [SPring-8/JASRI, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); KEK-PF, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Okumura, Hideo; Mizuno, Nobuhiro; Baba, Seiki [SPring-8/JASRI, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Hirata, Kunio [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Takeuchi, Tomoyuki; Yamazaki, Hiroshi; Senba, Yasunori; Ohashi, Haruhiko [SPring-8/JASRI, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Yamamoto, Masaki [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Kumasaka, Takashi, E-mail: kumasaka@spring8.or.jp [SPring-8/JASRI, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2013-11-01

    SPring-8 BL41XU provides a high-flux X-ray beam of size 10–50 µm, and enables high-quality diffraction data to be obtained from various types of protein crystals. Details of this beamline and an upgrade project are described. SPring-8 BL41XU is a high-flux macromolecular crystallography beamline using an in-vacuum undulator as a light source. The X-rays are monochromated by a liquid-nitrogen-cooling Si double-crystal monochromator, and focused by Kirkpatrick–Baez mirror optics. The focused beam size at the sample is 80 µm (H) × 22 µm (V) with a photon flux of 1.1 × 10{sup 13} photons s{sup −1}. A pinhole aperture is used to collimate the beam in the range 10–50 µm. This high-flux beam with variable size provides opportunities not only for micro-crystallography but also for data collection effectively making use of crystal volume. The beamline also provides high-energy X-rays covering 20.6–35.4 keV which allows ultra-high-resolution data to be obtained and anomalous diffraction using the K-edge of Xe and I. Upgrade of BL41XU for more rapid and accurate data collection is proceeding. Here, details of BL41XU are given and an outline of the upgrade project is documented.

  6. High-frequency fluxes of labile compounds in the central Ligurian Sea, northwestern Mediterranean

    Science.gov (United States)

    Goutx, M.; Momzikoff, A.; Striby, L.; Andersen, V.; Marty, J. C.; Vescovali, I.

    2000-03-01

    Sinking particles were collected every 4 h with drifting sediment traps deployed at 200 m depth in May 1995 in a 1-D vertical system during the DYNAPROC observations in the northwestern Mediterranean sea. POC, proteins, glucosamine and lipid classes were used as indicators of the intensity and quality of the particle flux. The roles of day/night cycle and wind on the particle flux were examined. The transient regime of production from late spring bloom to pre-oligotrophy determined the flux intensity and quality. POC fluxes decreased from, on average, 34 to 11 mg m -2 d -1, representing 6-14% of the primary production under late spring bloom conditions to 1-2% under pre-oligotrophic conditions. Total protein and chloroplast lipid fluxes correlated with POC and reflected the input of algal biomass into the traps. As the season proceeded, changes in the biochemical composition of the exported material were observed. The C/N ratio rose from 7.8 to 12. Increases of serine (10-28% of total proteins), total lipids (7-9 to 14-28% of POC) and reserve lipids (1-5 to 5-22% of total lipids) were noticeable, whereas total protein content in POC decreased (20-27 to 18-7%). N-acetyl glucosamine, a tracer of fecal pellet flux, showed that zooplankton grazing was a major vector of downward export during the decaying bloom. Against this background pattern, episodic events specifically increased the flux, modifying the quality and the settling velocity of particles. Day/night signals in biotracers (POC, N-acetyl glucosamine, protein and chloroplast lipids) showed that zooplankton migrations were responsible for sedimentation of fresh material through fast sinking particles ( V=170-180 m d -1) at night. Periodic signatures of re-processed material (high lipolysis and bacterial biomass indices) suggested that other zooplankton fecal pellets or small aggregates, probably of lower settling velocities ( V<170 m d -1), contributed to the flux during calm periods. At the beginning of the

  7. Enhanced modification of tungsten surface by nanostructure formation during high flux deuterium plasma exposure

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H.Y. [Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang, Sichuan 621907 (China); Luo, G.N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Schut, H. [Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Yuan, Y.; Fu, B.Q.; Godfrey, A. [Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, W., E-mail: liuw@mail.tsinghua.edu.cn [Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Temmerman, G.De. [FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research, Trilateral Euregio Cluster, Edisonbaan 14, 3439 MN Nieuwegein (Netherlands)

    2014-04-01

    The morphology changes induced by low energy deuterium ions on tungsten surfaces is studied for particle fluxes similar to those expected in the ITER divertor, as high as 10{sup 24} m{sup −2} s{sup −1}. A new type of surface modifications by formation of nanostructures is observed to occur under those conditions. The nanostructures formation is critically dependent on the particle flux and ion energy, and affected by surface temperature and particle fluence. It correlates with the formation of nano-cavities at a depth of about 40 nm below the surface. In addition, the positron annihilation Doppler broadening (PADB) measurements reveal a significant increase of defect concentration (mostly vacancy-type) after plasma exposure, and the evolution of defects is in line with the surface morphology changes with fluence and surface temperature. The possible mechanism of cyclic trap mutation and dislocation loop punching due to high flux D exposure is discussed.

  8. Enhanced modification of tungsten surface by nanostructure formation during high flux deuterium plasma exposure

    Science.gov (United States)

    Xu, H. Y.; Luo, G. N.; Schut, H.; Yuan, Y.; Fu, B. Q.; Godfrey, A.; Liu, W.; Temmerman, G. De.

    2014-04-01

    The morphology changes induced by low energy deuterium ions on tungsten surfaces is studied for particle fluxes similar to those expected in the ITER divertor, as high as 1024 m-2 s-1. A new type of surface modifications by formation of nanostructures is observed to occur under those conditions. The nanostructures formation is critically dependent on the particle flux and ion energy, and affected by surface temperature and particle fluence. It correlates with the formation of nano-cavities at a depth of about 40 nm below the surface. In addition, the positron annihilation Doppler broadening (PADB) measurements reveal a significant increase of defect concentration (mostly vacancy-type) after plasma exposure, and the evolution of defects is in line with the surface morphology changes with fluence and surface temperature. The possible mechanism of cyclic trap mutation and dislocation loop punching due to high flux D exposure is discussed.

  9. High diversity of methanotrophic bacteria in geothermal soils affected by high methane fluxes

    Science.gov (United States)

    D'Alessandro, Walter; Gagliano, Antonina Lisa; Quatrini, Paola; Parello, Francesco

    2014-05-01

    Volcanic and geothermal systems emit endogenous gases by widespread degassing from soils, including CH4, a greenhouse gas 25 times as potent as CO2. Recently, it has been demonstrated that volcanic/geothermal soils act as source, but also as biological filter for methane release to the atmosphere. For long time, volcanic/geothermal soils has been considered inhospitable for methanotrophic microorganisms, but new extremophile methanotrophs belonging to Verrucomicrobia were identified in three different areas (Pozzuoli, Italy; Hell's Gate, New Zealand; Kamchatka, Russia), explaining anomalous behaviours in methane leakages of several geothermal/volcanic sites. Our aim was to increase the knowledge of the relationship between methane emissions from volcanic/geothermal areas and biological methane oxidation, by investigating a geothermal site of Pantelleria island (Italy). Pantelleria Island hosts a high enthalpy geothermal system characterized by high temperature, high CH4 and very low H2S fluxes. Such characteristics are reflected in potentially great supply of methane for methanotrophs and scarce presence of inhibitors of their activity (H2S and NH3) in the Pantelleria soils. Potential methanotrophic activity within these soils was already evidenced by the CH4/CO2 ratio of the flux measurements which was lower than that of the respective fumarolic manifestations indicating a loss of CH4 during the gas travel towards the earth's surface. In this study laboratory incubation experiments using soils sampled at Favara Grande, the main hydrothermal area of Pantelleria, showed very high methane consumption rates (up to 9500 ng CH4 h-1 g-1). Furthermore, microbiological and culture-independent molecular analyses allowed to detect the presence of methanotrophs affiliated to Gamma- and Alpha-Proteobacteria and to the newly discovered acidothermophilic methanotrophs Verrucomicrobia. Culturable methanotrophic Alpha-proteobacteria of the genus Methylocystis were isolated by

  10. Prediction of forced gas flows in circular tubes at high heat fluxes accompanied by laminarization

    International Nuclear Information System (INIS)

    The application of high heat fluxes to turbulent gas flows causes significant variation of the gas properties due to the large temperature increase, invalidating the use of design relations such as the popular Dittus-Boelter correlation and of conventional turbulence models. To develop turbulence models for such flows, the predictive capabilities of a Reynolds stress equation model (RSM) with turbulence heat flux equations and of a k-kL-(u'v')-bar model were examined. We have employed the turbulence stress-thermal energy gradient production, in the pressure-temperature fluctuation gradient correlation, for the turbulence heat flux equations, in order to improve the accuracy of predictions for heat transfer accompanied by laminarization. The k-kL-(u'v')-bar model has already been validated for gas flows in annular tubes; in this study its applicability to a circular tube was examined. Validations were performed by comparison of predictions with constant fluid properties at fully-established conditions and to experimental measurements extending to laminarization conditions. The turbulence models both predict laminar and turbulent results and the approximate transition Reynolds number for the fully-established flow at low heat fluxes. The results predicted with both models also agreed well with data on laminarizing flows. Thus, the models presented here are capable of predicting the flow reasonably from low to high heat fluxes. (author)

  11. On the use of flat tile armour in high heat flux components

    International Nuclear Information System (INIS)

    The possibility to have a flat tile geometry for those high heat flux components subjected to a convective heat flux (namely the divertor dump target, lower vertical target, and the limiter) has been investigated. Because of the glancing incidence of the power load, if an armour tile falls off an extremely high heat flux hits the leading edge of the adjacent tile. As a result a rapid temperature increase occurs in the armour-heat sink joint. The heat flux to the water coolant also increases rapidly up to a factor of 1.7 and 2.3 for a beryllium and CFC armour, respectively, thus causing possible critical heat flux problems. Thermal stresses in the armour-heat sink joint double in less than 0.4 s and triplicate after 1 s thus leading to a possible cascade failure. Therefore the use of a flat tile geometry for these components does not seem to be appropriate. In this case a monoblock geometry gives a much more robust solution. (orig.)

  12. Brookhaven National Laboratory site environmental report for calendar year 1996

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, G.L.; Paquette, D.E.; Naidu, J.R.; Lee, R.J.; Briggs, S.L.K.

    1998-01-01

    This report documents the results of the Environmental Monitoring Program at Brookhaven National Laboratory and summarizes information about environmental compliance for 1996. To evaluate the effect of Brookhaven National Laboratory`s operations on the local environment, measurements of direct radiation, and of a variety of radionuclides and chemical compounds in the ambient air, soil, sewage effluent, surface water, groundwater, fauna, and vegetation were made at the Brookhaven National Laboratory site and at adjacent sites. The report also evaluates the Laboratory`s compliance with all applicable guides, standards, and limits for radiological and non-radiological emissions and effluents to the environment.

  13. Simulation of subcooled flow instability for high flux research reactors using the extended code ATHLET

    International Nuclear Information System (INIS)

    Covering the wide range of reactor safety analysis of power reactors, consisting of leak and transients, the thermohydraulic code ATHLET is being developed by the German Society for Plant and Reactor Safety (GRS). In order to extend the application range of the code to the safety analysis of low and medium flux research reactors, a model was developed and implemented permitting a description of the steam formation in the subcooled boiling regime. Considering the specific features of high flux research reactors given by both high heat flux and high flow velocity, further extension to the model of void condensation in subcooled flow has been extended and a new correlation of critical heat flux (CHF) is implemented. To validate the extended program, the thermal-hydraulic test loop (THTL) of oak ridge national laboratory (ORNL) was modeled and an extensive series of experiments concerning the onset of thermohydraulic flow instability (OFI) in subcooled boiling regime were calculated. The comparison between experiments and ATHLET post calculation shows that the extended code can accurately simulate the thermohydraulic conditions of flow instability in a wide range of heat flux up to 15 MW/m2 and inlet flow velocity up to 20 m/s. The thermohydraulic design limit characterized by the mass flux, at which the flow just becomes unstable (OFI), has been predicted in very good agreement with the experiment. However the calculated pressure drop at OFI is overestimated by a maximum deviation of about 25%. The calculated exit bulk temperature of subcooled coolant and the maximum wall temperature at OFI show a maximum deviation from experiment of 12% and 7% respectively. (author)

  14. High-Flux Hemodialysis and High-Volume Hemodiafiltration Improve Serum Calcification Propensity.

    Directory of Open Access Journals (Sweden)

    Marijke Dekker

    Full Text Available Calciprotein particles (CPPs may play an important role in the calcification process. The calcification propensity of serum (T50 is highly predictive of all-cause mortality in chronic kidney disease patients. Whether T50 is therapeutically improvable, by high-flux hemodialysis (HD or hemodiafiltration (HDF, has not been studied yet.We designed a cross-sectional single center study, and included stable prevalent in-center dialysis patients on HD or HDF. Patients were divided into two groups based on dialysis modality, were on a thrice-weekly schedule, had a dialysis vintage of > 3 months and vascular access providing a blood flow rate > 300 ml/min. Calcification propensity of serum was measured by the time of transformation from primary to secondary CPP (T50 test, by time-resolved nephelometry.We included 64 patients, mean convective volume was 21.7L (SD 3.3L. In the pooled analysis, T50 levels increased in both the HD and HDF group with pre- and post-dialysis (mean (SD of 244(64 - 301(57 and 253(55 - 304(61 min respectively (P = 0.43(HD vs. HDF. The mean increase in T50 was 26.29% for HD and 21.97% for HDF patients (P = 0.61 (HD vs. HDF. The delta values (Δ of calcium, phosphate and serum albumin were equal in both groups. Baseline T50 was negatively correlated with phosphate, and positively correlated with serum magnesium and fetuin-A. The ΔT50 was mostly influenced by Δ phosphate (r = -0.342; P = 0.002 HD and r = -0.396; P<0.001 HDF in both groups.HD and HDF patients present with same baseline T50 calcification propensity values pre-dialysis. Calcification propensity is significantly improved during both HD and HDF sessions without significant differences between both modalities.

  15. Production of high transient heat and particle fluxes in a linear plasma device

    NARCIS (Netherlands)

    De Temmerman, G.; Zielinski, J. J.; van der Meiden, H.; Melissen, W.; Rapp, J.

    2010-01-01

    We report on the generation of high transient heat and particle fluxes in a linear plasma device by pulsed operation of the plasma source. A capacitor bank is discharged into the source to transiently increase the discharge current up to 1.7 kA, allowing peak densities and temperature of 70x10(20) m

  16. A combined sensor for simultaneous high resolution 2-D imaging of oxygen and trace metals fluxes

    DEFF Research Database (Denmark)

    Stahl, Henrik; Warnken, Kent W.; Sochaczewski, Lukasz;

    2012-01-01

    (0.2 mu m) chelating resin and records the locally induced trace metal flux during the deployment, whereas the planar optode resolves the O-2 dynamic in near real time at the same location in the sediment. Despite its ultrathin composition, the DGT layer has high carrying capacity for trace metals...

  17. Operating manual for the High Flux Isotope Reactor. Volume I. Description of the facility

    International Nuclear Information System (INIS)

    This volume contains a comprehensive description of the High Flux Isotope Reactor Facility. Its primary purpose is to supplement the detailed operating procedures, providing the reactor operators with background information on the various HFIR systems. The detailed operating procdures are presented in another report

  18. The operating experience and incident analysis for High Flux Engineering Test Reactor

    International Nuclear Information System (INIS)

    The paper describes the incidents analysis for High Flux Engineering test reactor (HFETR) and introduces operating experience. Some suggestion have been made to reduce the incidents of HFETR. It is necessary to adopt new improvements which enhance the safety and reliability of operation. (author)

  19. Specifications for high flux isotope reactor fuel elements HFIR-FE-3

    International Nuclear Information System (INIS)

    This specification covers requirements for two types of aluminum-base fuel elements which together will be used as the fuel assembly in the High Flux Isotope Reactor (HFIR). Requirements are included for materials of construction, fabrication, assembly, inspection, and quality control to produce fuel elements in accordance with Company drawings

  20. Conceptual design of the high-flux VTA-2 test assembly for FMIT

    International Nuclear Information System (INIS)

    This report describes the conceptual design of the test module for the high neutron flux vertical test assembly (VTA-2). The description emphasizes the thermal control systems available for monitoring test specimen temperatures at any desired temperature within the range of 100 to 6500C. VTA-2 will be located in the Fusion Materials Irradiation Test Facility (FMIT) test cell directly behind VTA-1

  1. The inverse problem in zero linear ablation of aluminizing carbon composites under high heat flux

    Directory of Open Access Journals (Sweden)

    Huang Haiming

    2013-01-01

    Full Text Available The concept of zero linear ablation is introduced to describe the mass ablation without shape change, and it is employed to design thermal protection materials under an extreme thermal environment. Aluminizing carbon composites are used as a sample to study numerically the heat response. As indicated in the numerical results, the shape of the composites did not change under a high heat flux because the phase transition (melt or evaporation of aluminum can absorb a lot of energy before the ablation of carbon, and the zero linear ablation depends on not only the volume fraction of aluminum, but also the heating period and the heat flux.

  2. Gamma-ray-spectroscopy following high-flux 14-MeV neutron activation

    International Nuclear Information System (INIS)

    The Rotating Target Neutron Source (RTNS-I), a high-intensity source of 14-MeV neutrons at the Lawrence Livermore National Laboratory (LLNL), has been used for applications in activation analysis, inertial-confinement-fusion diagnostic development, and fission decay-heat studies. The fast-neutron flux from the RTNS-I is at least 50 times the maximum fluxes available from typical neutron generators, making these applications possible. Facilities and procedures necessary for gamma-ray spectroscopy of samples irradiated at the RTNS-I were developed

  3. High-flux beam source for cold, slow atoms or molecules

    OpenAIRE

    Maxwell, S. E.; Brahms, N.; deCarvalho, R.; Helton, J.; Nguyen, S V; Patterson, D; Doyle, J. M.; Glenn, D. R.; Petricka, J.; DeMille, D.

    2005-01-01

    We demonstrate and characterize a high-flux beam source for cold, slow atoms or molecules. The desired species is vaporized using laser ablation, then cooled by thermalization in a cryogenic cell of buffer gas. The beam is formed by particles exiting a hole in the buffer gas cell. We characterize the properties of the beam (flux, forward velocity, temperature) for both an atom (Na) and a molecule (PbO) under varying buffer gas density, and discuss conditions for optimizing these beam paramete...

  4. Development of high thermal flux components for continuous operation in Tokamaks

    International Nuclear Information System (INIS)

    High heat flux plasma facing components are under development and appropriate experimental evaluations have been carried out in order to operate during cycles of several hundred seconds. In Tore Supra, a large tokamak with a plasma nominal duration in excess of 30 seconds, solutions are tested that could be later applied to the NET/ITER tokamak, where peaked heat flux values of 15 MW/m2 on the divertor plates are foreseen. The proposed concept is a swirl square tube design protected with brazed CFC flat tiles. Development programs and validation tests are presented. The tests results are compared with calculations

  5. Gamma-ray-spectroscopy following high-flux 14-MeV neutron activation

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R.E.

    1981-10-12

    The Rotating Target Neutron Source (RTNS-I), a high-intensity source of 14-MeV neutrons at the Lawrence Livermore National Laboratory (LLNL), has been used for applications in activation analysis, inertial-confinement-fusion diagnostic development, and fission decay-heat studies. The fast-neutron flux from the RTNS-I is at least 50 times the maximum fluxes available from typical neutron generators, making these applications possible. Facilities and procedures necessary for gamma-ray spectroscopy of samples irradiated at the RTNS-I were developed.

  6. Neutron tomography experiments for the study of trapped flux distributions in high-Tc superconducting ceramics

    International Nuclear Information System (INIS)

    We describe a new version of Neutron Spin Echo, for the study of magnetic flux in high-Tc superconductors, which is based on the evolution of the echo group in the specimen which is installed in the third precession region. The polarization of the transmitted beam reflects the spin rotation in the internal field which can be found by Fourier transforming the data. It is required for example, in research on the flux self-organization in the critical state. Experiments on Y-Ba-Cu-O ceramics are discussed. (orig.)

  7. Magnetic-flux dynamics of high-Tc superconductors in weak magnetic fields

    DEFF Research Database (Denmark)

    Il’ichev, E. V.; Jacobsen, Claus Schelde

    1994-01-01

    Aspects of magnetic-flux dynamics in different types of samples of the high-temperature superconductor YBa2Cu3Ox have been investigated in magnetic fields below 1 Oe and at 77 K. The experiments were carried out in an arrangement including a field coil, a flat sample perpendicular to the field......, and a radio frequency-superconducting quantum interference device (RF-SQUID) along a common axis. For epitaxial thin films the Meissner effect was established. For a ceramic sample it was found that field changes of order 10(-2) Oe affect the flux distribution inside the sample. The observations can explain...

  8. Diffuse ultra-high energy neutrino fluxes and physics beyond the Standard Model

    International Nuclear Information System (INIS)

    We study spectral distortions of diffuse ultra-high energy (UHE) neutrino flavour fluxes resulting due to physics beyond the Standard Model (SM). Even large spectral differences between flavours at the source are massaged into a common shape at earth by SM oscillations, thus, any significant observed spectral differences are an indicator of new physics present in the oscillation probability during propagation. Lorentz symmetry violation (LV) and neutrino decay are examples, and result in significant distortion of the fluxes and of the well-known bounds on them, which may allow UHE detectors to probe LV parameters, lifetimes and the mass hierarchy over a broad range.

  9. Visualisation of flux distributions in high-temperature superconductors. Final report

    International Nuclear Information System (INIS)

    Theoretical calculation models for current, magnetic and electric field distributions in thin superconductors of arbitrary shape in perpendicular magnetic field were developed. Calculations were done for inhomogeneous and anisotropic critical currents and compared with magnetooptical observations of flux penetration. Nice agreement of theory and experiment was found. Flux-line depinning and motion in superconductors with linear defects was investigated by magneto-optics. Depinning mechanisms were deduced from observations of high-temperature superconductors which are irradiated with swift heavy ions parallel and crosswisely at various angles to the surface normal. Magneto-optical investigations of flux penetration into (Bi,Pb)2Sr2Ca2Cu3O10+δ multifilament tapes showed a strong dependence of the current capability on the microstructure of single filaments. The different filament textures which are caused by the inhomogeneous deformation of the tape during thermomechanical treatment results in critical current densities varying by about one order of magnitude. (orig.)

  10. PEAK FLUX DISTRIBUTIONS OF SOLAR RADIO TYPE-I BURSTS FROM HIGHLY RESOLVED SPECTRAL OBSERVATIONS

    International Nuclear Information System (INIS)

    Solar radio type-I bursts were observed on 2011 January 26 by high resolution observations with the radio telescope AMATERAS in order to derive their peak flux distributions. We have developed a two-dimensional auto burst detection algorithm that can distinguish each type-I burst element from complex noise storm spectra that include numerous instances of radio frequency interference (RFI). This algorithm removes RFI from the observed radio spectra by applying a moving median filter along the frequency axis. Burst and continuum components are distinguished by a two-dimensional maximum and minimum search of the radio dynamic spectra. The analysis result shows that each type-I burst element has one peak flux without double counts or missed counts. The peak flux distribution of type-I bursts derived using this algorithm follows a power law with a spectral index between 4 and 5.

  11. Peak Flux Distributions of Solar Radio Type-i Bursts from Highly Resolved Spectral Observations

    Science.gov (United States)

    Iwai, K.; Masuda, S.; Miyoshi, Y.; Tsuchiya, F.; Morioka, A.; Misawa, H.

    2013-05-01

    Solar radio type-I bursts were observed on 2011 January 26 by high resolution observations with the radio telescope AMATERAS in order to derive their peak flux distributions. We have developed a two-dimensional auto burst detection algorithm that can distinguish each type-I burst element from complex noise storm spectra that include numerous instances of radio frequency interference (RFI). This algorithm removes RFI from the observed radio spectra by applying a moving median filter along the frequency axis. Burst and continuum components are distinguished by a two-dimensional maximum and minimum search of the radio dynamic spectra. The analysis result shows that each type-I burst element has one peak flux without double counts or missed counts. The peak flux distribution of type-I bursts derived using this algorithm follows a power law with a spectral index between 4 and 5.

  12. Boiling transition and the possibility of spontaneous nucleation under high subcooling and high mass flux density flow in a tube

    International Nuclear Information System (INIS)

    Boiling transition and inverted annular heat transfer for R-113 have been investigated experimentally in a horizontal tube of 1.2 X 10/sup -3/ meter inner diameter with heating length over inner diameter ratio of 50. Experiments cover a high mass flux density range, a high local subcooling range and a wide local pressure range. Heat transfer characteristics were obtained by using heat flux control steady-state apparatus. Film boiling treated here is limited to the case of inverted annular heat transfer with very thin vapor film, on the order of 10/sup -6/ meter. Moreover, film boiling region is always limited to a certain downstream part, since the system has a pressure gradient along the flow direction. Discussions are presented on the parametric trends of boiling heat transfer characteristic curves and characteristic points. The possible existence is suggested of a spontaneous nucleation control surface boiling phenomena. And boiling transition heat flux and inverted annular heat transfer were correlated

  13. Fundamental aspects of deuterium retention in tungsten at high flux plasma exposure

    Energy Technology Data Exchange (ETDEWEB)

    Ogorodnikova, O. V., E-mail: igra32@rambler.ru [National Research Nuclear University “MEPHI,” Kashirskoe sh.31, 115409 Moscow (Russian Federation)

    2015-08-21

    An effect of enhanced trapping of deuterium in tungsten at high flux was discovered. It was shown analytically and confirmed experimentally that the deuterium trapping in a presence of high density of defects in tungsten (W) depends on the ion energy and ion flux. Newly developed analytical model explains experimentally observed discrepancy of deuterium trapping at radiation-induced defects in tungsten at different ion fluxes that significantly improves a prediction of hydrogen isotope accumulation in different plasma devices, including ITER and DEMO. The developed model can be used for many system of hydrogen in a metal in both normal and extreme environments (high fluxes, elevated temperatures, neutron irradiation, etc.). This new model allows, for the first time, to validate density function theory (DFT) predictions of multiple occupation of a defect with deuterium against experimental data that bridge the gap in length and time scale between DFT calculations and experiments. By comparing first-principle calculations based on DFT and semi-empirical “adsorption model,” it was proved that the mechanism of hydrogen isotope trapping in a vacancy cluster is similar to a chemisorption on a surface. Binding energies of deuterium with different types of defects in W were defined. Moreover, the surface barrier of deuterium to be chemisorbed on a clean W surface was found to be less than 1 eV and kinetics of deuterium release is limited by de-trapping from defects rather than to be limited by surface effects.

  14. Institute for High Heat Flux Removal (IHHFR). Phases I, II, and III

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Ronald D. [Prairie View A& M Univ., TX (United States)

    2014-08-31

    The IHHFR focused on interdisciplinary applications as it relates to high heat flux engineering issues and problems which arise due to engineering systems being miniaturized, optimized, or requiring increased high heat flux performance. The work in the IHHFR focused on water as a coolant and includes: (1) the development, design, and construction of the high heat flux flow loop and facility; (2) test section development, design, and fabrication; and, (3) single-side heat flux experiments to produce 2-D boiling curves and 3-D conjugate heat transfer measurements for single-side heated test sections. This work provides data for comparisons with previously developed and new single-side heated correlations and approaches that address the single-side heated effect on heat transfer. In addition, this work includes the addition of single-side heated circular TS and a monoblock test section with a helical wire insert. Finally, the present work includes: (1) data base expansion for the monoblock with a helical wire insert (only for the latter geometry), (2) prediction and verification using finite element, (3) monoblock model and methodology development analyses, and (4) an alternate model development for a hypervapotron and related conjugate heat transfer controlling parameters.

  15. Fundamental aspects of deuterium retention in tungsten at high flux plasma exposure

    International Nuclear Information System (INIS)

    An effect of enhanced trapping of deuterium in tungsten at high flux was discovered. It was shown analytically and confirmed experimentally that the deuterium trapping in a presence of high density of defects in tungsten (W) depends on the ion energy and ion flux. Newly developed analytical model explains experimentally observed discrepancy of deuterium trapping at radiation-induced defects in tungsten at different ion fluxes that significantly improves a prediction of hydrogen isotope accumulation in different plasma devices, including ITER and DEMO. The developed model can be used for many system of hydrogen in a metal in both normal and extreme environments (high fluxes, elevated temperatures, neutron irradiation, etc.). This new model allows, for the first time, to validate density function theory (DFT) predictions of multiple occupation of a defect with deuterium against experimental data that bridge the gap in length and time scale between DFT calculations and experiments. By comparing first-principle calculations based on DFT and semi-empirical “adsorption model,” it was proved that the mechanism of hydrogen isotope trapping in a vacancy cluster is similar to a chemisorption on a surface. Binding energies of deuterium with different types of defects in W were defined. Moreover, the surface barrier of deuterium to be chemisorbed on a clean W surface was found to be less than 1 eV and kinetics of deuterium release is limited by de-trapping from defects rather than to be limited by surface effects

  16. The Role and Detectability of the Charm Contribution to Ultra High Energy Neutrino Fluxes

    CERN Document Server

    Gandhi, Raj; Watanabe, Atsushi

    2009-01-01

    It is widely believed that charm meson production and decay may play an important role in high energy astrophysical sources of neutrinos, especially those that are baryon-rich, providing an environment conducive to pp interactions. Using slow-jet supernovae (SJS) as an example of such a source, we study the detectability of high-energy neutrinos, paying particular attention to those produced from charmed-mesons. We highlight important distinguishing features in the ultra-high energy neutrino flux which would act as markers for the role of charm in the source. In particular, charm leads to significant event rates at higher energies, after the conventional (pi, K) neutrino fluxes fall off. We calculate event rates both for a nearby single source and for diffuse SJS fluxes for an IceCube-like detector. By comparing muon event rates for the conventional and prompt fluxes in different energy bins, we demonstrate the striking energy dependence in the rates induced by the presence of charm. We also show that it lead...

  17. Characteristics of Magnetic Tribology on High Flux Pair of Magnetic Driving Mechanism

    Institute of Scientific and Technical Information of China (English)

    ZHOUQiang; XURui-qing; XUHong-qiu

    2004-01-01

    The rectangle-like pulsed magnetic field acted on the rubbing pair was presents through analyzing the exciting property in the reciprocationg travel the test of wear in NG-x tester shows that the wear between the electromagnetic core and down magnetic board distributes in the high veloctity slip region of reciprocating travel,an the adhesive wear in the low velocity slip region nearby up and down dead points is depressed owing to the presence of high flux magnetic field.the lubrication by magnetic fluid with high permeability effectively reduces the friction and wear of high flux rubbing pair and mproves the conductiong property of magnetic circuit constructed by the rubbing pair which is beneficial to increase the operation performance of magnetic driving mechanism.

  18. New Brookhaven chief seeks cross-cutting research

    CERN Multimedia

    Jones, D

    2003-01-01

    Brookhaven National Laboratory will pursue opportunities for promoting commercial development of energy systems and other technologies while focusing on the lab's primary mission of basic science research, according to the incoming BNL director, Praveen Chaudhari (1 page).

  19. Superlattice-based thin-film thermoelectric modules with high cooling fluxes

    OpenAIRE

    Bulman, Gary; Barletta, Phil; Lewis, Jay; Baldasaro, Nicholas; Manno, Michael; Bar-Cohen, Avram; Yang, Bao

    2016-01-01

    In present-day high-performance electronic components, the generated heat loads result in unacceptably high junction temperatures and reduced component lifetimes. Thermoelectric modules can, in principle, enhance heat removal and reduce the temperatures of such electronic devices. However, state-of-the-art bulk thermoelectric modules have a maximum cooling flux q max of only about 10 W cm−2, while state-of-the art commercial thin-film modules have a q max

  20. Brookhaven at 40 - looking forward as well as back

    International Nuclear Information System (INIS)

    In 1947, the famous Camp Upton Army Base on New York's Long Island switched to a new career as Brookhaven National Laboratory. The reputation the Laboratory has established as a world-class research centre and its continued attraction for scientists looking for exciting possibilities were highlighted on 9-11 September at a symposium and celebration marking forty years of Brookhaven and its parent organization, AUI (Associated Universities Inc)

  1. Report on the Brookhaven Solar Neutrino Experiment

    Science.gov (United States)

    Davis, R. Jr.; Evans, J. C. Jr.

    1976-09-22

    This report is intended as a brief statement of the recent developments and results of the Brookhaven Solar Neutrino Experiment communicated through Professor G. Kocharov to the Leningrad conference on active processes on the sun and the solar neutrino problem. The report summarizes the results of experiments performed over a period of 6 years, from April 1970 to January 1976. Neutrino detection depends upon the neutrino capture reaction /sup 37/Cl(..nu..,e/sup -/)/sup 37/Ar producing the isotope /sup 37/Ar (half life of 35 days). The detector contains 3.8 x 10/sup 5/ liters of C/sub 2/Cl/sub 4/ (2.2 x 10/sup 30/ atoms of /sup 37/Cl) and is located at a depth of 4400 meters of water equivalent (m.w.e.) in the Homestake Gold Mine at Lead, South Dakota, U.S.A. The procedures for extracting /sup 37/Ar and the counting techniques used were described in previous reports. The entire recovered argon sample was counted in a small gas proportional counter. Argon-37 decay events were characterized by the energy of the Auger electrons emitted following the electron capture decay and by the rise-time of the pulse. Counting measurements were continued for a period sufficiently long to observe the decay of /sup 37/Ar.

  2. Simulation of subcooled flow instability for high flux research reactors using the extended code ATHLET

    International Nuclear Information System (INIS)

    Covering the wide range of reactor safety analysis of power reactors, consisting of leak and transients, the thermohydraulic code ATHLET is being developed by the Gesellschaft for Anlagen- und Reaktorsicherheit (GRS-Society for Plant and Reactor Safety) (Lerchel, G., Austregesilo, H., 1998. ATHLET Mode 1.2 Cycle A, User's Manual, GRS-p-1/Vol. 1, Rev. 1, GRS). In order to extend the code's range of application to the safety analysis of research reactors, a model was developed and implemented permitting a description of the steam formation in the subcooled boiling regime (Hainoun, A., 1994. Modellierung des unterkuehlten Siedens in ATHLET und Anwendung in wassergekuehlten Forschungsreaktoren, D 294 Diss. Univ. Bochum, Juel-2961). Considering the specific features of high flux research reactors given by both high heat flux and high flow velocity, the model of void condensation in subcooled flow has been extended and a new correlation of critical heat flux (CHF) is implemented. To validate the extended program, the Thermal-Hydraulic Test Loop (THTL) of Oak Ridge National Laboratory (ORNL) was modeled with ATHLET and an extensive series of experiments concerning the onset of thermohydraulic flow instability (OFI) in subcooled boiling regime were calculated. The comparison between experiments and ATHLET-postcalculation shows that the extended code can accurately simulate the thermohydraulic conditions of flow instability in a wide range of heat flux up to 15 MW m-2 and inlet flow velocity up to 20 m s-1. The thermohydraulic design limit characterized by the mass flux, at which the flow just becomes unstable (OFI), has been predicted in very good agreement with the experiment. However the calculated pressure drop at OFI is overestimated by a maximum deviation of about 25%. The calculated exit bulk temperature of subcooled coolant and the maximum wall temperature at OFI show a maximum deviation from experiment of 12 and 7%, respectively

  3. Green house gas flux at high latitudes - constraints and susceptibility to a changing climate

    Science.gov (United States)

    Nilsson, M. B.

    2015-12-01

    High latitude boreal forests and peatlands contribute importantly to the land-atmosphere exchange of both carbon dioxide and methane. High latitude biomes are also identified as most vulnerable to changing climate. High latitudes are characterized by a strong seasonality in incoming solar radiation, weather conditions and biogeochemical processes. The strong seasonality in incoming solar radiation, not to change in response to a changing climate, constitute firm constraints on how changes in air temperature, evapotranspiration and precipitation will affect biogeochemical processes underlying the land atmosphere exchange of green house gases. Timing of the soil frost thaw and plant phenology thus constitutes two master controls on how fluxes of both CO2 and CH4 will be affected by weather conditions. In addition also the wintertime conditions importantly affect GHG fluxes both during winter time as well as during the succeeding summer. Examples will primarily be given for peatlands and coniferous forests.

  4. Deuterium-induced nanostructure formation on tungsten exposed to high-flux plasma

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H.Y., E-mail: donaxu@163.com [Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang, Sichuan 621907 (China); De Temmerman, G. [FOM Institute DIFFER, Dutch Institute For Fundamental Energy Research, Ass. EURATOM-FOM, Trilateral Euregio Cluster, Postbus 1207, 3430BE Nieuwegein (Netherlands); ITER Organization, Route de Vinon-sur-Verdon CS 90046-13067, St Paul Lez Durance Cedex (France); Luo, G.-N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Jia, Y.Z.; Yuan, Y.; Fu, B.Q.; Godfrey, A. [Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, W., E-mail: liuw@mail.tsinghua.edu.cn [Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2015-08-15

    Surface topography of polycrystalline tungsten (W) have been examined after exposure to a low-energy (38 eV/D), high-flux (∼1.1–1.5 × 10{sup 24} m{sup −2} s{sup −1}) deuterium plasma in the Pilot-PSI linear plasma device. The methods used were scanning electron microscopy (SEM), transmission electron microscopy (TEM), positron annihilation Doppler broadening (PADB) and grazing incident X-ray diffraction (GI-XRD). After exposure to high flux D plasma, blisters and nanostructures are formed on the W surface. Generation of defects was evidenced by PADB, while high stress and mixture of phases were detected in depth of 50 nm by GI-XRD. TEM observation revealed fluctuations and disordered microstructure on the outmost surface layer. Based on these results, surface reconstruction is considered as a possible mechanism for the formation of defects and nanostructures.

  5. Performance Test of High Heat Flux Test Facility for the Calorimetry and Beam Control

    International Nuclear Information System (INIS)

    The Korea Heat Load Test facility, KoHLT-EB (Electron Beam) has been operating for the plasma facing components to develop fusion engineering in Korea. The ITER Neutral Beam Duct Liner (NBDL) was fabricated and tested to qualify the thermocouple fixation method for the temperature measurement during a direct collision of the high-power neutral beam during ITER operation. The NBDL is CuCrZr panels, which are actively water cooled using deep drilled channels. To perform the profile test, the assessment for the possibility of an electron beam Gaussian power density profile and the result of absorbed power for that profile before the test start is needed. To assess the possibility of Gaussian profile, for the qualification test of a Gaussian heat load profile, small calorimetry was manufactured to simulate a real heat profile in the neutral beam duct liner, and this calorimetry has two cooling channel with five thermocouples, which is the same as NBDL. Preliminary analyses with ANSYSCFX using a 3D model were performed with the calorimetry model. The heating area was modeled to be 60 mm x 250 mm. The simulated heat flux is 0.5 - 1.2 MW/m''2 at 0.75 kg/sec of the water flow rate. A steady heat flux test was performed to measure the surface heat flux, surface temperature profile. With a thermohydraulic analysis and heat load test, the Gaussian heat profile will be confirmed for this calorimetry and NBDL mockup. The Korean heat load test facility will be used to qualify the specifications of various plasma facing components in fusion devices. To conduct a beam profile test, an assessment of the possibility of electron beam Gaussian power density profile and the results of the absorbed power for that profile before the test starts are needed. To assess the possibility of a Gaussian profile, for the qualification test of the Gaussian heat load profile, a calorimeter mockup and large Cu module were manufactured to simulate real heat. For this high-heat flux test

  6. Testing of research reactor fuel in the high flux reactor (Petten)

    International Nuclear Information System (INIS)

    The two types of fuel most frequently used by the main research reactors are metallic: highly enriched uranium (>90%) and silicide low enriched uranium (3. However, a need exists for research on new reactor fuel. This would permit some plants to convert without losses in flux or in cycle length and would allow new reactor projects to achieve higher possibilities especially in fluxes. In these cases research is made either on silicide with higher density, or on other types of fuel (UMo, etc.). In all cases when new fuel is proposed, there is a need, for safety reasons, to test it, especially regarding the mechanical evolution due to burn-up (swelling, etc.). Initially, such tests are often made with separate plates, but lately, using entire elements. Destructive examinations are often necessary. For this type of test, the High Flux Reactor, located in Petten (The Netherlands) has many specific advantages: a large core, providing a variety of interesting positions with high fluence rate; a downward coolant flow simplifies the engineering of the device; there exists easy access with all handling possibilities to the hot-cells; the high number of operating days (>280 days/year), together with the high flux, gives a possibility to reach quickly the high burn-up needs; an experienced engineering department capable of translating specific requirements to tailor-made experimental devices; a well equipped hot-cell laboratory on site to perform all necessary measurements (swelling, γ-scanning, profilometry) and all destructive examinations. In conclusion, the HFR reactor readily permits experimental research on specific fuels used for research reactors with all the necessary facilities on the Petten site. (author)

  7. Future management of hazardous wastes generated at Brookhaven National Laboratory, Upton, New York. Environmental assessment

    International Nuclear Information System (INIS)

    This document assesses the potential environmental impacts of a variety of alternatives which could provide a Resource Conservation and Recovery Act (RCRA) permitted waste packaging and storage facility that would handle all hazardous, radioactive, and mixed wastes generated at Brookhaven National Laboratory (BNL) and would operate in full compliance with all federal, state, and local laws and regulations. Location of the existing Hazardous Waste Management Facility (HWMF) with respect to ground water and the site boundary, technical and capacity limitations, inadequate utilities, and required remediation of the area make the existing facility environmentally unacceptable for long term continued use. This Environmental Assessment (EA) describes the need for action by the Department of Energy (DOE). It evaluates the alternatives for fulfilling that need, including the alternative preferred by DOE, a no-action alternative, and other reasonable alternatives. The EA provides a general description of BNL and the existing environment at the current HWMF and alternative locations considered for a new Waste Management Facility (WMF). Finally, the EA describes the potential environmental impacts of the alternatives considered. The preferred alternative, also identified as Alternative D, would be to construct and operate a new WMF on land formerly occupied by barracks during Camp Upton operations, in an area north of Building 830 and the High Flux Beam Reactor/Alternating Gradient Synchrotron (AGS) recharge basins, east of North Railroad Street, and south of East Fifth Avenue. The purpose of this new facility would be to move all storage and transfer activities inside buildings and on paved and curbed areas, consolidate facilities to improve operations management, and provide improved protection of the environment

  8. Superlattice-based thin-film thermoelectric modules with high cooling fluxes

    Science.gov (United States)

    Bulman, Gary; Barletta, Phil; Lewis, Jay; Baldasaro, Nicholas; Manno, Michael; Bar-Cohen, Avram; Yang, Bao

    2016-01-01

    In present-day high-performance electronic components, the generated heat loads result in unacceptably high junction temperatures and reduced component lifetimes. Thermoelectric modules can, in principle, enhance heat removal and reduce the temperatures of such electronic devices. However, state-of-the-art bulk thermoelectric modules have a maximum cooling flux qmax of only about 10 W cm-2, while state-of-the art commercial thin-film modules have a qmax management of modern high-power devices. Here we show that cooling fluxes of 258 W cm-2 can be achieved in thin-film Bi2Te3-based superlattice thermoelectric modules. These devices utilize a p-type Sb2Te3/Bi2Te3 superlattice and n-type δ-doped Bi2Te3-xSex, both of which are grown heteroepitaxially using metalorganic chemical vapour deposition. We anticipate that the demonstration of these high-cooling-flux modules will have far-reaching impacts in diverse applications, such as advanced computer processors, radio-frequency power devices, quantum cascade lasers and DNA micro-arrays.

  9. Status of design and validation tasks for the IFMIF high flux test module

    Energy Technology Data Exchange (ETDEWEB)

    Arbeiter, F.; Heinzel, V.; Scheel, N.; Heupel, T.; Dolensky, B.; Chen, Y.; Klein, C.; Stratmanns, E. [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (DE). Inst. fuer Neutronenphysik und Reaktortechnik (INR)

    2010-05-15

    The IFMIF High Flux Test Module (HFTM) is the dedicated assembly to bring material specimens into the high neutron flux region of the IFMIF neutron source [1] and maintain the specified irradiation conditions. The material specimens are destined for Post Irradiation Examination (PIE, for example mechanical or micro-structural testing) after an irradiation period of several months up to years. Irradiation conditions are specified by neutron flux, neutron energy spectrum, and temperature, as well as the spatial and temporal variations of these quantities. It is the objective of the HFTM to provide precise adherence to the specified irradiation conditions, and to maximize the irradiation performance, expressed as the multiplicity of specimens times their damage rates (displacements per atom per full power year, dpa/fpy). The HFTM and its components must also integrate with logistic processes (especially hot-cell operations), to reach a high availability of the IFMIF facility. Since the material temperature plays a major role in the progress of the radiation induced structural damage, a precise adherence to the prescribed irradiation temperature of any individual specimen set is stringently important in order to obtain high quality data for material research. The design of the HFTM assembly and its irradiation capsules has well advanced and is presented here for the status of December 2009. (orig.)

  10. Investigation of ionized metal flux in enhanced high power impulse magnetron sputtering discharges

    Energy Technology Data Exchange (ETDEWEB)

    Stranak, Vitezslav, E-mail: stranak@prf.jcu.cz [Faculty of Science, University of South Bohemia, Branisovska 31, 37005 Ceske Budejovice (Czech Republic); Hubicka, Zdenek; Cada, Martin [Institute of Physics v. v. i., Academy of Science of the Czech Republic, Na Slovance 2, 182 21 Prague (Czech Republic); Drache, Steffen; Hippler, Rainer [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); Tichy, Milan [Faculty of Mathematics and Physics, Charles University in Prague, V Holesovickach 2, 180 00 Prague (Czech Republic)

    2014-04-21

    The metal ionized flux fraction and production of double charged metal ions Me{sup 2+} of different materials (Al, Cu, Fe, Ti) by High Power Impulse Magnetron Sputtering (HiPIMS) operated with and without a pre-ionization assistance is compared in the paper. The Electron Cyclotron Wave Resonance (ECWR) discharge was employed as the pre-ionization agent providing a seed of charge in the idle time of HiPIMS pulses. A modified grid-free biased quartz crystal microbalance was used to estimate the metal ionized flux fraction ξ. The energy-resolved mass spectrometry served as a complementary method to distinguish particular ion contributions to the total ionized flux onto the substrate. The ratio between densities of doubly Me{sup 2+} and singly Me{sup +} charged metal ions was determined. It is shown that ECWR assistance enhances Me{sup 2+} production with respect of absorbed rf-power. The ECWR discharge also increases the metal ionized flux fraction of about 30% especially in the region of lower pressures. Further, the suppression of the gas rarefaction effect due to enhanced secondary electron emission of Me{sup 2+} was observed.

  11. Use of higher order signal moments and high speed digital sampling technique for neutron flux measurement

    International Nuclear Information System (INIS)

    The second (conventional variance or Campbell signal) , , , the third , and the modified fourth order - 3*2 etc. central signal moments associated with the amplified (K) and filtered currents [i1, i2, x = K * (i2-2>),] from two electrodes of an ex-core neutron sensitive fission detector have been measured versus the reactor power of the 1 MW TRIGA reactor in Mexico City. Two channels of a high speed (400 kHz) multiplexing data sampler and A/D converter with 12 bit resolution and one megawords buffer memory were used. The data were further retrieved into a PC and estimates for auto- and cross-correlation moments up to the fifth order, coherence (/√), skewness (/(√/)3), excess (/2 - 3) etc. quantities were calculated off-line. A five mode operation of the detector was achieved including the conventional counting rates and currents in agreement with the theory and the authors previous results with analogue techniques. The signals were proportional to the neutron flux and reactor power in some flux ranges. The suppression of background noise is improved and the lower limit of the measurement range is extended as the order of moment is increased, in agreement with the theory. On the other hand the statistical uncertainty is increased. At increasing flux levels it was statistically more difficult to obtain flux estimates based on the higher order (≥3) moments

  12. Qualification, commissioning and in situ monitoring of high heat flux plasma facing components

    International Nuclear Information System (INIS)

    Up-to-date development of actively cooled high heat flux (HHF) plasma facing components (PFC) prototypes only allows reduced margins with regards to the ITER thermal requirements. Additionally, perfect quality cannot be ensured along series manufacturing: the presence of flaws which impair the heat transfer capability of the component, in particular at the interface armour/heat sink appears to be statistically unavoidable. In order to ensure a successful series production, a qualification methodology of actively cooled high heat flux plasma facing components is proposed. Secondly, advanced non-destructive techniques developed for HHF PFC commissioning are detailed with definition of acceptance criteria. Finally, innovative diagnostics for in situ monitoring during plasma operations or tokamak shutdowns are investigated in order to prevent immediate damage (safety monitoring); or evaluate component degradation (health monitoring). This work takes into account the relevance to Tore Supra, and is applied to W7X and ITER Divertor HHF PFC

  13. Nanostructured fuzz growth on tungsten under low-energy and high-flux He irradiation

    Science.gov (United States)

    Yang, Qi; You, Yu-Wei; Liu, Lu; Fan, Hongyu; Ni, Weiyuan; Liu, Dongping; Liu, C. S.; Benstetter, Günther; Wang, Younian

    2015-06-01

    We report the formation of wave-like structures and nanostructured fuzzes in the polycrystalline tungsten (W) irradiated with high-flux and low-energy helium (He) ions. From conductive atomic force microscope measurements, we have simultaneously obtained the surface topography and current emission images of the irradiated W materials. Our measurements show that He-enriched and nanostructured strips are formed in W crystal grains when they are exposed to low-energy and high-flux He ions at a temperature of 1400 K. The experimental measurements are confirmed by theoretical calculations, where He atoms in W crystal grains are found to cluster in a close-packed arrangement between {101} planes and form He-enriched strips. The formations of wave-like structures and nanostructured fuzzes on the W surface can be attributed to the surface sputtering and swelling of He-enriched strips, respectively.

  14. B-mode generated by high-frequency gravitational waves and corresponding perturbative photon fluxes

    CERN Document Server

    Li, Fangyu; Fang, Zhenyun

    2015-01-01

    Interaction of very low-frequency primordial(relic) gravitational waves(GWs) to cosmic microwave background(CMB) can generate B-mode polarization. Here, for the first time we point out that the electromagnetic(EM) response to high-frequency GWs(HFGWs) would produce B-mode distribution of the perturbative photon fluxes, and study the duality and high complementarity between such two B-modes. Based on this B-mode in HFGWs, it is shown that the distinguishing and observing of HFGWs from the braneworld would be quite possible due to their large amplitude, higher frequency and very different physical behaviors between the perturbative photon fluxes and background photons, and the measurement of relic HFGWs may also be possible though face to enormous challenge.

  15. Cooling high heat flux micro-electronic systems using refrigerants in high aspect ratio multi-microchannel evaporators

    International Nuclear Information System (INIS)

    Improving the energy efficiency of cooling systems can contribute to reduce the emission of greenhouse gases. Currently, most microelectronic applications are air-cooled. Switching to two-phase cooling systems would decrease power consumption and allow for the reuse of the extracted heat. For this type of application, multi-microchannel evaporators are thought to be well adapted. However, such devices have not been tested for a wide range of operating conditions, such that their thermal response to the high non-uniform power map typically generated by microelectronics has not been studied. This research project aims at clarifying these gray areas by investigating the behavior of the two-phase flow of different refrigerants in silicon and copper multi-microchannel evaporators under uniform, non-uniform and transient heat fluxes operating conditions. The test elements use as a heat source a pseudo-chip able to mimic the behavior of a CPU. It is formed by 35 independent sub-heaters, each having its own temperature sensor, such that 35 temperature and 35 heat flux measurements can be made simultaneously. Careful measurements of each pressure drop component (inlet, microchannels and outlet) found in the micro-evaporators showed the importance of the inlet and outlet restriction pressure losses. The overall pressure drop levels found in the copper test section were low enough to possibly be driven by a thermosyphon system. The heat transfer coefficients measured for uniform heat flux conditions were very high and typically followed a V-shape curve. The first branch was associated to the slug flow regime and the second to the annular flow regime. By tracking the minimum level of heat transfer, a transition criteria between the regimes was established, which included the effect of heat flux on the transition. Then for each branch, a different prediction method was used to form the first flow pattern-based prediction method for two-phase heat transfer in microchannels. A

  16. Deuterium-induced nanostructure formation on tungsten exposed to high-flux plasma

    NARCIS (Netherlands)

    Xu, H.Y.; De Temmerman, G.; Luo, G. N.; Jia, Y. Z.; Yuan, Y.; Fu, B. Q.; Godfrey, A.; Liu, W.

    2015-01-01

    Surface topography of polycrystalline tungsten (W) have been examined after exposure to a low-energy (38 eV/D), high-flux (∼1.1–1.5 × 1024 m−2 s−1) deuterium plasma in the Pilot-PSI linear plasma device. The methods used were scanning electron microscopy

  17. Expected Number and Flux Distribution of Gamma-Ray-Burst Afterglows with High Redshifts

    OpenAIRE

    Ciardi, Benedetta; Loeb, Abraham

    2000-01-01

    If Gamma-Ray-Bursts (GRBs) occur at high redshifts, then their bright afterglow emission can be used to probe the ionization and metal enrichment histories of the intervening intergalactic medium during the epoch of reionization. In contrast to other sources, such as galaxies or quasars, which fade rapidly with increasing redshift, the observed infrared flux from a GRB afterglow at a fixed observed age is only a weak function of its redshift. This results from a combination of the spectral sl...

  18. Neutron Radiography Facility at IBR-2 High Flux Pulsed Reactor: First Results

    Science.gov (United States)

    Kozlenko, D. P.; Kichanov, S. E.; Lukin, E. V.; Rutkauskas, A. V.; Bokuchava, G. D.; Savenko, B. N.; Pakhnevich, A. V.; Rozanov, A. Yu.

    A neutron radiography and tomography facilityhave been developed recently at the IBR-2 high flux pulsed reactor. The facility is operated with the CCD-camera based detector having maximal field of view of 20x20 cm, and the L/D ratio can be varied in the range 200 - 2000. The first results of the radiography and tomography experiments with industrial materials and products, paleontological and geophysical objects, meteorites, are presented.

  19. Conceptual design of the high-flux VTA-2 test assembly for FMIT

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, M.A.

    1983-08-01

    This report describes the conceptual design of the test module for the high neutron flux vertical test assembly (VTA-2). The description emphasizes the thermal control systems available for monitoring test specimen temperatures at any desired temperature within the range of 100 to 650/sup 0/C. VTA-2 will be located in the Fusion Materials Irradiation Test Facility (FMIT) test cell directly behind VTA-1.

  20. Concepts for using trapped-flux bulk high-temperature superconductor in motors and generators

    International Nuclear Information System (INIS)

    We review previous concepts for using bulk high-temperature superconductors (HTSs) in motors and generators and discuss methods for using trapped-flux (TF) HTSs in motors and generators that have been recently investigated in our laboratory. We examine the expected performance of a brushless motor/generator that uses TF bulk HTSs to provide magnetomotive force, where the stator windings are used to create the TF. A key feature is the use of dysprosium for the stator and rotor cores.

  1. The response time analysis of high log neutron flux rate for heavy water reactors

    International Nuclear Information System (INIS)

    The heavy water reactor such as Wolssung no. 1 has a protection/safety system named special safety system. The system has four safety systems ; shutdown no. 1, shutdown no. 2, emergency core cooling system and containment system. In this paper, the response time of high log neutron flux rate, one of the reactor trip loops of shutdown no.1/no.2, was analysed based on the description of final safety analysis report and compared to the plant measurement

  2. Review of current status of high flux heat transfer techniques. Volume I. Text + Appendix A

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, W.H.; Gordon, H.S.; Lackner, H.; Mettling, J.R.; Miller, J.E.

    1980-09-01

    The scope of this work comprised two tasks. The first was to review high heat flux technology with consideration given to heat transfer panel configuration, diagnostics techniques and coolant supply. The second task was to prepare a report describing the findings of the review, to recommend the technology offering the least uncertainty for scale-up for the MFTF-B requirement and to recommend any new or perceived requirements for R and D effort.

  3. Review of current status of high flux heat transfer techniques. Volume I. Text + Appendix A

    International Nuclear Information System (INIS)

    The scope of this work comprised two tasks. The first was to review high heat flux technology with consideration given to heat transfer panel configuration, diagnostics techniques and coolant supply. The second task was to prepare a report describing the findings of the review, to recommend the technology offering the least uncertainty for scale-up for the MFTF-B requirement and to recommend any new or perceived requirements for R and D effort

  4. Fluxes of nitrates between snow surfaces and the atmosphere in the European high Arctic

    OpenAIRE

    H. J. Beine; Dominè, F.; Ianniello, A.; Nardino, M.; Allegrini, I.; K. Teinilä; Hillamo, R.

    2003-01-01

    Measurements of atmospheric and snow mixing ratios of nitrates and nitrites and their fluxes above the snow surface were made during two intensive campaigns during spring time 2001 at Ny-Ålesund, Svalbard as part of the EU project  "`The NItrogen Cycle and Effects on the oxidation of atmospheric trace species at high latitudes" (NICE). At this coastal site close to the unseasonably unfrozen fjord, of the measured nitrogen species, only ...

  5. Investigating the use of nanofluids to improve high heat flux cooling systems

    OpenAIRE

    Barrett, T R; Robinson, S.; Flinders, K; Sergis, A; Hardalupas, Y.

    2013-01-01

    The thermal performance of high heat flux components in a fusion reactor could be enhanced significantly by the use of nanofluid coolants, suspensions of a liquid with low concentrations of solid nanoparticles. However, before they are considered viable for fusion, the long-term behaviour of nanofluids must be investigated. This paper reports an experiment which is being prepared to provide data on nanofluid stability, settling and erosion in a HyperVapotron device. Procedures are demonstrate...

  6. Explanation for the Low Flux of High Energy Astrophysical Muon Neutrinos

    International Nuclear Information System (INIS)

    There has been some concern about the unexpected paucity of cosmic high energy muon neutrinos in detectors probing the energy region beyond 1 PeV. As a possible solution we consider the possibility that some exotic neutrino property is responsible for reducing the muon neutrino flux at high energies from distant sources; specifically, we consider: (i) neutrino decay and (ii) neutrinos being pseudo-Dirac particles. This would provide a mechanism for the reduction of high energy muon events in the IceCube detector, for example

  7. Advanced Multiphysics Thermal-Hydraulics Models for the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Prashant K [ORNL; Freels, James D [ORNL

    2015-01-01

    Engineering design studies to determine the feasibility of converting the High Flux Isotope Reactor (HFIR) from using highly enriched uranium (HEU) to low-enriched uranium (LEU) fuel are ongoing at Oak Ridge National Laboratory (ORNL). This work is part of an effort sponsored by the US Department of Energy (DOE) Reactor Conversion Program. HFIR is a very high flux pressurized light-water-cooled and moderated flux-trap type research reactor. HFIR s current missions are to support neutron scattering experiments, isotope production, and materials irradiation, including neutron activation analysis. Advanced three-dimensional multiphysics models of HFIR fuel were developed in COMSOL software for safety basis (worst case) operating conditions. Several types of physics including multilayer heat conduction, conjugate heat transfer, turbulent flows (RANS model) and structural mechanics were combined and solved for HFIR s inner and outer fuel elements. Alternate design features of the new LEU fuel were evaluated using these multiphysics models. This work led to a new, preliminary reference LEU design that combines a permanent absorber in the lower unfueled region of all of the fuel plates, a burnable absorber in the inner element side plates, and a relocated and reshaped (but still radially contoured) fuel zone. Preliminary results of estimated thermal safety margins are presented. Fuel design studies and model enhancement continue.

  8. High Temperature Erosion Wear of Cermet Particles Reinforced Self-Fluxing Alloy HVOF Sprayed Coatings

    Directory of Open Access Journals (Sweden)

    Andrei SURZHENKOV

    2015-09-01

    Full Text Available The resistance of high velocity oxy-fuel (HVOF sprayed TiC-NiMo and Cr3C2-Ni cermet particles reinforced NiCrSiB self-fluxing alloy coatings to high temperature erosion wear was studied. Microstructure of the coatings was examined by SEM, phase composition was determined by XRD. A four-channel centrifugal particle accelerator was applied to study the high temperature erosion wear of the coatings. The angles of impingement were 30º and 90º, initial particle velocity was 50 m/s, the average temperature of the test – 650 ºC. Volume wear of the coatings was calculated and compared to the respective values of the reference materials. Wear mechanisms were studied by SEM. HVOF sprayed coatings exhibited lower wear, than WC-15Co hardmetal and steel HARDOX 400, but higher wear than steel AISI 304. TiC-NiMo particles reinforced self-fluxing alloy coating demonstrated virtually the same wear resistance, as the Cr3C2-Ni particles reinforced self-fluxing alloy coating, at 30º and the better wear resistance at 90º.

  9. Optimization of Depletion Modeling and Simulation for the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Betzler, Benjamin R [ORNL; Ade, Brian J [ORNL; Chandler, David [ORNL; Ilas, Germina [ORNL; Sunny, Eva E [ORNL

    2015-01-01

    Monte Carlo based depletion tools used for the high-fidelity modeling and simulation of the High Flux Isotope Reactor (HFIR) come at a great computational cost; finding sufficient approximations is necessary to make the use of these tools feasible. The optimization of the neutronics and depletion model for the HFIR is based on two factors: (i) the explicit representation of the involute fuel plates with sets of polyhedra and (ii) the treatment of depletion mixtures and control element position during depletion calculations. A very fine representation (i.e., more polyhedra in the involute plate approximation) does not significantly improve simulation accuracy. The recommended representation closely represents the physical plates and ensures sufficient fidelity in regions with high flux gradients. Including the fissile targets in the central flux trap of the reactor as depletion mixtures has the greatest effect on the calculated cycle length, while localized effects (e.g., the burnup of specific isotopes or the power distribution evolution over the cycle) are more noticeable consequences of including a critical control element search or depleting burnable absorbers outside the fuel region.

  10. Coupling soil Carbon Fluxes, Soil Microbes, and High-Resolution Carbon Profiling in Permafrost Transitions

    Science.gov (United States)

    Anderson, C.; Stegen, J.; Bond-Lamberty, B. P.; Tfaily, M. M.; Huang, M.; Liu, Y.

    2015-12-01

    Microbial communities play a central role in the functioning of natural ecosystems by heavily influencing biogeochemical cycles. Understanding how shifts in the environment are tied to shifts in biogeochemical rates via changes in microbial communities is particularly relevant in high latitude terrestrial systems underlain by permafrost due to vast carbon stocks currently stored within thawing permafrost. There is limited understanding, however, of the interplay among soil-atmosphere CO2 fluxes, microbial communities, and SOM chemical composition. To address this knowledge gap, we leverage the distinct spatial transitions in permafrost-affected soils at the Caribou Poker Creek Research Watershed, a 104 km2 boreal watershed ~50 km north of Fairbanks, AK. We integrate a variety of data to gain new knowledge of the factors that govern observed patterns in the rates of soil CO2 fluxes associated with permafrost to non-permafrost transition zones. We show that nonlinearities in fluxes are influenced by depth to permafrost, tree stand structure, and soil C composition. Further, using 16S sequencing methods we explore microbial community assembly processes and their connection to CO2 flux across spatial scales, and suggest a path to more mechanistically link microbes to large-scale biogeochemical cycles. Lastly, we use the Community Land Model (CLM) to compare Earth System Model predictions of soil C cycling with empirical measurements. Deviations between CLM predictions and field observations of CO2 flux and soil C stocks will provide insight for how the model may be improved through inclusion of additional biotic (e.g., microbial community composition) and abiotic (e.g., organic carbon composition) features, which will be critical to improve the predictive power of climate models in permafrost-affected regions.

  11. A regional high-resolution carbon flux inversion of North America for 2004

    Science.gov (United States)

    Schuh, A. E.; Denning, A. S.; Corbin, K. D.; Baker, I. T.; Uliasz, M.; Parazoo, N.; Andrews, A. E.; Worthy, D. E. J.

    2010-05-01

    Resolving the discrepancies between NEE estimates based upon (1) ground studies and (2) atmospheric inversion results, demands increasingly sophisticated techniques. In this paper we present a high-resolution inversion based upon a regional meteorology model (RAMS) and an underlying biosphere (SiB3) model, both running on an identical 40 km grid over most of North America. Current operational systems like CarbonTracker as well as many previous global inversions including the Transcom suite of inversions have utilized inversion regions formed by collapsing biome-similar grid cells into larger aggregated regions. An extreme example of this might be where corrections to NEE imposed on forested regions on the east coast of the United States might be the same as that imposed on forests on the west coast of the United States while, in reality, there likely exist subtle differences in the two areas, both natural and anthropogenic. Our current inversion framework utilizes a combination of previously employed inversion techniques while allowing carbon flux corrections to be biome independent. Temporally and spatially high-resolution results utilizing biome-independent corrections provide insight into carbon dynamics in North America. In particular, we analyze hourly CO2 mixing ratio data from a sparse network of eight towers in North America for 2004. A prior estimate of carbon fluxes due to Gross Primary Productivity (GPP) and Ecosystem Respiration (ER) is constructed from the SiB3 biosphere model on a 40 km grid. A combination of transport from the RAMS and the Parameterized Chemical Transport Model (PCTM) models is used to forge a connection between upwind biosphere fluxes and downwind observed CO2 mixing ratio data. A Kalman filter procedure is used to estimate weekly corrections to biosphere fluxes based upon observed CO2. RMSE-weighted annual NEE estimates, over an ensemble of potential inversion parameter sets, show a mean estimate 0.57 Pg/yr sink in North America

  12. On the Relationship Between High Speed Solar Wind Streams and Radiation Belt Electron Fluxes

    Science.gov (United States)

    Zheng, Yihua

    2011-01-01

    Both past and recent research results indicate that solar wind speed has a close connection to radiation belt electron fluxes [e.g., Paulikas and Blake, 1979; Reeves et aI., 2011]: a higher solar wind speed is often associated with a higher level of radiation electron fluxes. But the relationship can be very complex [Reeves et aI., 2011]. The study presented here provides further corroboration of this viewpoint by emphasizing the importance of a global perspective and time history. We find that all the events during years 2010 and 2011 where the >0.8 MeV integral electron flux exceeds 10(exp 5) particles/sq cm/sr/s (pfu) at GEO orbit are associated with the high speed streams (HSS) following the onset of the Stream Interaction Region (SIR), with most of them belonging to the long-lasting Corotating Interaction Region (CIR). Our preliminary results indicate that during HSS events, a maximum speed of 700 km/s and above is a sufficient but not necessary condition for the > 0.8 MeV electron flux to reach 10(exp 5) pfu. But in the exception cases of HSS events where the electron flux level exceeds the 10(exp 5) pfu value but the maximum solar wind speed is less than 700 km/s, a prior impact can be noted either from a CME or a transient SIR within 3-4 days before the arrival of the HSS - stressing the importance of time history. Through superposed epoch analysis and studies providing comparisons with the CME events and the HSS events where the flux level fails to reach the 10(exp 5) pfu, we will present the quantitative assessment of behaviors and relationships of various quantities, such as the time it takes to reach the flux threshold value from the stream interface and its dependence on different physical parameters (e.g., duration of the HSS event, its maximum or average of the solar wind speed, IMF Bz, Kp). The ultimate goal is to apply what is derived to space weather forecasting.

  13. Reduced flux motion via flux creep annealing in high- Jc single-crystal Y1Ba2Cu3O7

    International Nuclear Information System (INIS)

    We investigated the stabilization of magnetic flux in a high-temperature superconductor (a proton-irradiated Y1Ba2Cu3O7 crystal), by operating with subcritical current density J. Using the thermal history to obtain an induced current density J≤Jc, we observed a drastically reduced relaxation rate dM/dt (M=magnetization), after ''flux creep annealing.'' The results show that the field gradient ∼J∼M determined the relaxation rate, independent of the sample's H-T history, in agreement with recent theory

  14. HOM identification by bead pulling in the Brookhaven ERL cavity

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, H., E-mail: hahnh@bnl.gov [Collider–Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Calaga, R. [Collider–Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); European Organization for Nuclear Research, 1211 Geneva (Switzerland); Jain, Puneet; Johnson, Elliott C. [Physics and Astronomy Department, Stony Brook University, Stony Brook, NY 117943 (United States); Xu, Wencan [Collider–Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2014-01-11

    Exploratory measurements of the Brookhaven Energy Recovery Linac (ERL) cavity at superconducting temperature produced a long list of high order modes (HOMs). The niobium 5-cell cavity is terminated at each end with HOM ferrite dampers that successfully reduce the Q-factors to levels required to avoid beam break up (BBU) instabilities. However, a number of un-damped resonances with Q≥10{sup 6} were found at 4 K and their mode identification forms the focus of this paper. The approach taken here consists of bead pulling on a copper (Cu) replica of the ERL cavity with dampers involving various network analyzer measurements. Several different S{sub 21} transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, others between beam-position monitor probes in the beam tubes, and also between probes placed into the cells. The bead pull technique suitable for HOM identification with a metallic needle or dielectric bead is detailed. This paper presents the results for HOMs in the first two dipole bands, the un-damped modes in the first quadrupole band, and the identification of several high-Q modes beyond.

  15. The program of the ALARA Center at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    In 1984 the Brookhaven National Laboratory was asked by the Nuclear Regulatory Commission to set up a Center to monitor dose-reduction efforts in the US and abroad and to focus the industry's attention on ALARA. The paper summarizes the main work of the ALARA Center between 1984 and 1992. The Center maintains nine data bases for the NRC and the Nuclear Power Industry. These databases are constantly updated and access to them is provided through a personal computer and a modem and by periodic publications in the form of a newsletter and NUREG reports. Also described briefly are eight other projects related to dose-reduction at nuclear power plants that the Center has carried out for the NRC. Among these are projects that analyze the cost-effectiveness of engineering modifications, look at worldwide activities at dose reduction and compare US and foreign dose experience, examine high-dose worker groups and high-dose jobs, develop optimum techniques to control contamination at nuclear plants, and look at the doses being received by men and women in all sectors of the nuclear industry

  16. Eddy covariance flux measurements of ammonia by high temperature chemical ionisation mass spectrometry

    Directory of Open Access Journals (Sweden)

    J. Sintermann

    2011-03-01

    Full Text Available A system for fast ammonia (NH3 measurements with chemical ionisation mass spectrometry (CIMS based on a commercial Proton Transfer Reaction-Mass Spectrometer (PTR-MS is presented. It uses electron transfer reaction as ionisation pathway and features a drift tube of polyetheretherketone (PEEK and silica-coated steel. Heating the instrumental inlet and the drift tube to 180 °C enabled an effective time resolution of ~1 s and made it possible to apply the instrument for eddy covariance (EC measurements. EC fluxes of NH3 were measured over two agricultural fields in Oensingen, Switzerland, following fertilisations with cattle slurry. Air was aspirated close to a sonic anemometer at a flow of 100 STP L min−1 and was directed through a 23 m long 1/2" PFA tube heated to 150 °C to an air-conditioned trailer where the gas was sub-sampled from the large bypass stream. This setup minimised damping of fast NH3 concentration changes between the sampling point and the actual measurement. High-frequency attenuation loss of the NH3 fluxes of 20 to 40% was quantified and corrected for using an empirical ogive method. The instrumental NH3 background signal showed a minor interference with H2O which was characterised in the laboratory. The resulting correction of the NH3 flux after slurry spreading was less than 1‰. The flux detection limit of the EC system was about 5 ng m−2 s−1 while the accuracy of individual flux measurements was estimated 16% for the high-flux regime during these experiments. The NH3 emissions after broad spreading of the slurry showed an initial maximum of 150 μg m−2 s−1 with a fast decline in the following hours.

  17. High-energy neutrino fluxes and flavor ratio in the Earth atmosphere

    CERN Document Server

    Sinegovskaya, T S; Sinegovsky, S I

    2014-01-01

    High-energy neutrinos from decays of mesons, produced in collisions of cosmic-ray particles with air nuclei, form unavoidable background for detection of astrophysical neutrinos. More precise calculations of the high-energy neutrino spectrum are required since measurements in the IceCube experiment reach the intriguing energy range where a contribution of the prompt neutrinos and/or astrophysical ones should be uncovered. The calculation of muon and electron neutrino fluxes in the energy range 100 GeV - 10 PeV is performed for three hadronic models, QGSJET II, SIBYll 2.1 and Kimel & Mokhov, taking into consideration the "knee" of the cosmic-ray spectrum. All calculations are compared with the atmospheric neutrino measurements by Frejus, AMANDA, IceCube and ANTARES. The prompt neutrino flux predictions obtained with the quark-gluon string model (QGSM) for the charm production by Kaidalov & Piskunova do not contradict to the measurements and upper limits on the astrophysical muon neutrino flux obtained ...

  18. The preparation of BP single crystals by high pressure flux method

    Science.gov (United States)

    Kumashiro, Y.; Misawa, S.; Gonda, S.

    1984-01-01

    Single crystals of BP, a III-V compound semiconductor, were obtained by the high pressure flux method. Cu3P and Ni12P5 powders were used as the flux, and mixed with BP powder. Two kinds of mixtures were prepared: (1) 1.8g (BP) + 35 G (Cu3P) and (2) 1.7 g (BP) + 25 g (Ni12P5). They were compressed into pellets, heated at 1300 C for 24 h in an induction furnace under a pressure of 1 MPa using Ar-P2 gas, and slowly cooled to room temperature. In case (1), BP single crystals grew along the (III) plane, and in case (2) they grew as an aggregate of crystallites. The cathodoluminescence spectra of the synthetic BP crystals showed peaks near 680 nm (1.82 eV) for case (1), and 500 nm (2.47 eV) for case (2). By using the high pressure flux method conventional sized crystals were obtained in a relatively short time.

  19. Double-cavity radiometer for high-flux density solar radiation measurements.

    Science.gov (United States)

    Parretta, A; Antonini, A; Armani, M; Nenna, G; Flaminio, G; Pellegrino, M

    2007-04-20

    A radiometric method has been developed, suitable for both total power and flux density profile measurement of concentrated solar radiation. The high-flux density radiation is collected by a first optical cavity, integrated, and driven to a second optical cavity, where, attenuated, it is measured by a conventional radiometer operating under a stationary irradiation regime. The attenuation factor is regulated by properly selecting the aperture areas in the two cavities. The radiometer has been calibrated by a pulsed solar simulator at concentration levels of hundreds of suns. An optical model and a ray-tracing study have also been developed and validated, by which the potentialities of the radiometer have been largely explored. PMID:17415384

  20. Limits on diffuse fluxes of high energy extraterrestrial neutrinos with the AMANDA-B10 detector

    International Nuclear Information System (INIS)

    Data from the AMANDA-B10 detector taken during the austral winter of 1997 have been searched for a diffuse flux of high energy extraterrestrial muon-neutrinos, as predicted from, e.g., the sum of all active galaxies in the universe. This search yielded no excess events above those expected from the background atmospheric neutrinos, leading to upper limits on the extraterrestrial neutrino flux. For an assumed E-2 spectrum, a 90 percent classical confidence level upper limit has been placed at a level E2 Phi(E) = 8.4 x 10-7 GeV cm-2 s-11 sr-1 (for a predominant neutrino energy range 6-1000 TeV) which is the most restrictive bound placed by any neutrino detector. When specific predicted spectral forms are considered, it is found that some are excluded

  1. Calculations for HFIR [High Flux Isotope Reactor] fuel plate non- bonding and fuel segregation uncertainty factors

    International Nuclear Information System (INIS)

    The effects of non-bonds and of fuel segregation on the package factors of the heat flux in the High Flux Isotope Reactor (HFIR) are examined. The effects of the two defects are examined both separately and together. It is concluded that the peaking factors that are used in the present HFIR thermal analysis code are conservative and thus no changes in the peaking factors are necessary to continue to ensure that HFIR is safe. A study was made of the effect of the non-bond spot diameter on the peaking factor. The conclusion is that the spot can have diameter more than three times the maximum value allowed by the specifications before the peaking factor is greater than the maximum value specified in the present HFIR thermal analysis code. 6 refs., 7 figs., 8 tabs

  2. Alize 3 - first critical experiment for the franco-german high flux reactor - calculations

    International Nuclear Information System (INIS)

    The results of experiments in the light water cooled D2O reflected critical assembly ALIZE III have been compared to calculations. A diffusion model was used with 3 fast and epithermal groups and two overlapping thermal groups, which leads to good agreement of calculated and measured power maps, even in the case of strong variations of the neutron spectrum in the core. The difference of calculated and measured keff was smaller than 0.5 per cent δk/k. Calculations of void and structure material coefficients of the reactivity of 'black' rods in the reflector, of spectrum variations (Cd-ratio, Pu-U-ratio) and to the delayed photoneutron fraction in the D2O reflector were made. Measurements of the influence of beam tubes on reactivity and flux distribution in the reflector were interpreted with regard to an optimum beam tube arrangement for the Franco- German High Flux Reactor. (author)

  3. Molecular dynamic simulation of tungsten ablation under transient high heat flux

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Sha, E-mail: syan@pku.edu.cn [Institute of Heavy Ion Physics, State Key Laboratory of Nuclear Science and Technology, Peking University, Beijing 100871 (China); Zhu, Yizhou; Xue, Jianming [Institute of Heavy Ion Physics, State Key Laboratory of Nuclear Science and Technology, Peking University, Beijing 100871 (China); Zhang, Jie; Qu, Miao; Le, Xiaoyun [School of Physical Science and Nuclear Engineering, Beihang University, Beijing 100191 (China)

    2015-08-15

    Molecular dynamic (MD) method is used to simulation the tungsten ablation under transient high heat flux generated by energetic ions. A model including 363,600 W atoms was built based on Finnis–Sinclair potential. The results show that the ablation threshold is much lower than the one of boiling. So the ablation effects might be underestimated if using energy threshold of boiling instead of that of ablation. Particle size distribution of ablation products follows a power decay law with an exponent around −2.5, which does not affect by the incident heat flux. The transverse velocities of particles obey normal distribution, and a stream speed is added to the random movement for the longitudinal velocity. As the ablation start up, the recoiled impulse can induce shock wave in remained target, which is supported by experimental pressure wave measurements.

  4. High-flux water desalination with interfacial salt sieving effect in nanoporous carbon composite membranes

    CERN Document Server

    Chen, Wei; Zhang, Qiang; Fan, Zhongli; Huang, Kuo-Wei; Zhang, Xixiang; Lai, Zhiping; Sheng, Ping

    2016-01-01

    Nanoporous carbon composite membranes, comprising a layer of porous carbon fiber structures with an average channel width of 30-60 nm grown on a porous ceramic substrate, are found to exhibit robust desalination effect with high freshwater flux. In three different membrane processes of vacuum membrane distillation, reverse osmosis and forward osmosis, the carbon composite membrane showed 100% salt rejection with 3.5 to 20 times higher freshwater flux compared to existing polymeric membranes. Thermal accounting experiments found that at least 80% of the freshwater pass through the carbon composite membrane with no phase change. Molecular dynamics simulations revealed a unique salt rejection mechanism. When seawater is interfaced with either vapor or the surface of carbon, one to three interfacial atomic layers contain no salt ions. Below the liquid entry pressure, the salt solution is stopped at the openings to the porous channels and forms a meniscus, while the surface layer of freshwater can feed the surface...

  5. Optical design of a high radiative flux solar furnace for Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Riveros-Rosas, D.; Perez-Rabago, C.A.; Arancibia-Bulnes, C.A.; Jaramillo, O.A.; Estrada, C.A. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Av. Xochicalco s/n, A.P. 34, Temixco, 62580 Morelos (Mexico); Herrera-Vazquez, J.; Vazquez-Montiel, S.; Granados-Agustin, F. [Instituto Nacional de Astrofisica, Optica y Electronica, Luis Enrique Erro 1, Tonantzintla, A.P. 216, 72000 Puebla (Mexico); Sanchez-Gonzalez, M. [Centro Nacional de Energias Renovables, Calle Somera 7-9, 28026 Madrid (Spain)

    2010-05-15

    In the present work, the optical design of a new high radiative flux solar furnace is described. Several optical configurations for the concentrator of the system have been considered. Ray tracing simulations were carried out in order to determine the concentrated radiative flux distributions in the focal zone of the system, for comparing the different proposals. The best configuration was chosen in terms of maximum peak concentration, but also in terms of economical and other practical considerations. It consists of an arrangement of 409 first surface spherical facets with hexagonal shape, mounted on a spherical frame. The individual orientation of the facets is corrected in order to compensate for aberrations. The design considers an intercepted power of 30 kW and a target peak concentration above 10,000 suns. The effect of optical errors was also considered in the simulations. (author)

  6. High-accuracy determination of the neutron flux at n{sub T}OF

    Energy Technology Data Exchange (ETDEWEB)

    Barbagallo, M.; Colonna, N.; Mastromarco, M.; Meaze, M.; Tagliente, G.; Variale, V. [Sezione di Bari, INFN, Bari (Italy); Guerrero, C.; Andriamonje, S.; Boccone, V.; Brugger, M.; Calviani, M.; Cerutti, F.; Chin, M.; Ferrari, A.; Kadi, Y.; Losito, R.; Versaci, R.; Vlachoudis, V. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Tsinganis, A. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); National Technical University of Athens (NTUA), Athens (Greece); Tarrio, D.; Duran, I.; Leal-Cidoncha, E.; Paradela, C. [Universidade de Santiago de Compostela, Santiago (Spain); Altstadt, S.; Goebel, K.; Langer, C.; Reifarth, R.; Schmidt, S.; Weigand, M. [Johann-Wolfgang-Goethe Universitaet, Frankfurt (Germany); Andrzejewski, J.; Marganiec, J.; Perkowski, J. [Uniwersytet Lodzki, Lodz (Poland); Audouin, L.; Leong, L.S.; Tassan-Got, L. [Centre National de la Recherche Scientifique/IN2P3 - IPN, Orsay (France); Becares, V.; Cano-Ott, D.; Garcia, A.R.; Gonzalez-Romero, E.; Martinez, T.; Mendoza, E. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain); Becvar, F.; Krticka, M.; Kroll, J.; Valenta, S. [Charles University, Prague (Czech Republic); Belloni, F.; Fraval, K.; Gunsing, F.; Lampoudis, C.; Papaevangelou, T. [Commissariata l' Energie Atomique (CEA) Saclay - Irfu, Gif-sur-Yvette (France); Berthoumieux, E.; Chiaveri, E. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Commissariata l' Energie Atomique (CEA) Saclay - Irfu, Gif-sur-Yvette (France); Billowes, J.; Ware, T.; Wright, T. [University of Manchester, Manchester (United Kingdom); Bosnar, D.; Zugec, P. [University of Zagreb, Department of Physics, Faculty of Science, Zagreb (Croatia); Calvino, F.; Cortes, G.; Gomez-Hornillos, M.B.; Riego, A. [Universitat Politecnica de Catalunya, Barcelona (Spain); Carrapico, C.; Goncalves, I.F.; Sarmento, R.; Vaz, P. [Universidade Tecnica de Lisboa, Instituto Tecnologico e Nuclear, Instituto Superior Tecnico, Lisboa (Portugal); Cortes-Giraldo, M.A.; Praena, J.; Quesada, J.M.; Sabate-Gilarte, M. [Universidad de Sevilla, Sevilla (Spain); Diakaki, M.; Karadimos, D.; Kokkoris, M.; Vlastou, R. [National Technical University of Athens (NTUA), Athens (Greece); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. [CSIC-Universidad de Valencia, Instituto de Fisica Corpuscular, Valencia (Spain); Dressler, R.; Kivel, N.; Schumann, D.; Steinegger, P. [Paul Scherrer Institut, Villigen PSI (Switzerland); Dzysiuk, N.; Mastinu, P.F. [Laboratori Nazionali di Legnaro, INFN, Rome (Italy); Eleftheriadis, C.; Manousos, A. [Aristotle University of Thessaloniki, Thessaloniki (Greece); Ganesan, S.; Gurusamy, P.; Saxena, A. [Bhabha Atomic Research Centre (BARC), Mumbai (IN); Griesmayer, E.; Jericha, E.; Leeb, H. [Technische Universitaet Wien, Atominstitut, Wien (AT); Hernandez-Prieto, A. [European Organization for Nuclear Research (CERN), Geneva (CH); Universitat Politecnica de Catalunya, Barcelona (ES); Jenkins, D.G.; Vermeulen, M.J. [University of York, Heslington, York (GB); Kaeppeler, F. [Institut fuer Kernphysik, Karlsruhe Institute of Technology, Campus Nord, Karlsruhe (DE); Koehler, P. [Oak Ridge National Laboratory (ORNL), Oak Ridge (US); Lederer, C. [Johann-Wolfgang-Goethe Universitaet, Frankfurt (DE); University of Vienna, Faculty of Physics, Vienna (AT); Massimi, C.; Mingrone, F.; Vannini, G. [Universita di Bologna (IT); INFN, Sezione di Bologna, Dipartimento di Fisica, Bologna (IT); Mengoni, A.; Ventura, A. [Agenzia nazionale per le nuove tecnologie, l' energia e lo sviluppo economico sostenibile (ENEA), Bologna (IT); Milazzo, P.M. [Sezione di Trieste, INFN, Trieste (IT); Mirea, M. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN HH, Bucharest - Magurele (RO); Mondalaers, W.; Plompen, A.; Schillebeeckx, P. [Institute for Reference Materials and Measurements, European Commission JRC, Geel (BE); Pavlik, A.; Wallner, A. [University of Vienna, Faculty of Physics, Vienna (AT); Rauscher, T. [University of Basel, Department of Physics and Astronomy, Basel (CH); Roman, F. [European Organization for Nuclear Research (CERN), Geneva (CH); Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN HH, Bucharest - Magurele (RO); Rubbia, C. [European Organization for Nuclear Research (CERN), Geneva (CH); Laboratori Nazionali del Gran Sasso dell' INFN, Assergi (AQ) (IT); Weiss, C. [European Organization for Nuclear Research (CERN), Geneva (CH); Johann-Wolfgang-Goethe Universitaet, Frankfurt (DE)

    2013-12-15

    The neutron flux of the n{sub T}OF facility at CERN was measured, after installation of the new spallation target, with four different systems based on three neutron-converting reactions, which represent accepted cross sections standards in different energy regions. A careful comparison and combination of the different measurements allowed us to reach an unprecedented accuracy on the energy dependence of the neutron flux in the very wide range (thermal to 1 GeV) that characterizes the n{sub T}OF neutron beam. This is a pre-requisite for the high accuracy of cross section measurements at n{sub T}OF. An unexpected anomaly in the neutron-induced fission cross section of {sup 235}U is observed in the energy region between 10 and 30keV, hinting at a possible overestimation of this important cross section, well above currently assigned uncertainties. (orig.)

  7. High luminous flux from single crystal phosphor-converted laser-based white lighting system

    KAUST Repository

    Cantore, Michael

    2015-12-14

    The efficiency droop of light emitting diodes (LEDs) with increasing current density limits the amount of light emitted per wafer area. Since low current densities are required for high efficiency operation, many LED die are needed for high power white light illumination systems. In contrast, the carrier density of laser diodes (LDs) clamps at threshold, so the efficiency of LDs does not droop above threshold and high efficiencies can be achieved at very high current densities. The use of a high power blue GaN-based LD coupled with a single crystal Ce-doped yttrium aluminum garnet (YAG:Ce) sample was investigated for white light illumination applications. Under CW operation, a single phosphor-converted LD (pc-LD) die produced a peak luminous efficacy of 86.7 lm/W at 1.4 A and 4.24 V and a peak luminous flux of 1100 lm at 3.0 A and 4.85 V with a luminous efficacy of 75.6 lm/W. Simulations of a pc-LD confirm that the single crystal YAG:Ce sample did not experience thermal quenching at peak LD operating efficiency. These results show that a single pc-LD die is capable of emitting enough luminous flux for use in a high power white light illumination system.

  8. Realization of a flux-flow DC-transformer using high temperature superconductors

    International Nuclear Information System (INIS)

    This paper reports on the first realization using high temperature superconducting films of the device proposed in 1965 by Giaever: the DC-DC transformer, which involves flux-flow vortex motion in two superimposed thin films, separated by a thin insulating layer. The device was fabricated using the ramp based multilayer technology from an YBa2Cu3O7 based SIS structure grown by pulsed laser deposition. Transport measurements exhibiting the coupling and decoupling phenomena between the two vortex arrays are obtained. We discuss the possibility of widening the working range of this device, which constitutes an important result in the effort to use high temperature superconductors for electronics. (orig.)

  9. Calculation of critical experiment parameters for the High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    Six critical experiments were performed shortly before the initial ascension to power of the High Flux Isotope Reactor (HFIR). Critical configurations were determined at various control rod positions by varying the soluble boron content in the light water coolant. Calculated k-effective was 2% high at beginning-of-life (BOL) typical conditions, but was 1.0 at end-of-life (EOL) typical conditions. Axially averaged power distributions for a given radial location were frequently within experimental error. At specific r,z locations with the core, the calculated power densities were significantly different from the experimentally derived values. A reassessment of the foil activation data seems desirable

  10. Design of a high-flux instrument for ultrafast electron diffraction and microscopy

    Science.gov (United States)

    Filippetto, D.; Qian, H.

    2016-05-01

    We present the design and optimization of a new instrument for ultrafast electron diffraction and imaging. The proposed instrument merges the high peak current and relativistic electron energies of radio-frequency guns, with the high average electron flux of static electron microscopes, extending the beam parameter space achievable with relativistic electrons by many orders of magnitude. An immediate consequence of this work is a broader range of accessible science by using electron probes, enabling techniques as femtosecond nano-diffraction and coherent diffraction imaging, and paving the way to direct observation of ultrafast dynamics in complex and isolated samples, from nanocrystals, to nano/micro droplets and organic molecules.

  11. Response of aluminium and its alloys to exposure in the high flux isotope reactor

    International Nuclear Information System (INIS)

    Pure aluminum and some aluminum alloys were irradiated to very high neutron fluences in the cooling water at 328 K in the high flux region of HFIR. Displacement levels of 270 dpa and transmutation-produced silicon levels of 7.15 wt% were reached. Damage microstructures consisted of dislocations, cavities and precipitates which caused substantial strengthening and associated loss in ductility. Formation of cavities and related swelling were considerably reduced by alloying elements and by the presence of fine Mg2Si precipitate. (author)

  12. In vivo neutron activation facility at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Ma, R.; Yasumura, Seiichi; Dilmanian, F.A.

    1997-11-01

    Seven important body elements, C, N, Ca, P, K, Na, and Cl, can be measured with great precision and accuracy in the in vivo neutron activation facilities at Brookhaven National Laboratory. The facilities include the delayed-gamma neutron activation, the prompt-gamma neutron activation, and the inelastic neutron scattering systems. In conjunction with measurements of total body water by the tritiated-water dilution method several body compartments can be defined from the contents of these elements, also with high precision. In particular, body fat mass is derived from total body carbon together with total body calcium and nitrogen; body protein mass is derived from total body nitrogen; extracellular fluid volume is derived from total body sodium and chlorine; lean body mass and body cell mass are derived from total body potassium; and, skeletal mass is derived from total body calcium. Thus, we suggest that neutron activation analysis may be valuable for calibrating some of the instruments routinely used in clinical studies of body composition. The instruments that would benefit from absolute calibration against neutron activation analysis are bioelectric impedance analysis, infrared interactance, transmission ultrasound, and dual energy x-ray/photon absorptiometry.

  13. HOM identification by bead pulling in the Brookhaven ERL cavity

    Energy Technology Data Exchange (ETDEWEB)

    Hahn H.; Calaga, R.; Jain, P.; Johnson, E.C.; Xu, W.

    2012-06-25

    Several past measurements of the Brookhaven ERL at superconducting temperature produced a long list of higher order modes (HOMs). The Niobium 5-cell cavity is terminated with HOM ferrite dampers that successfully reduce the Q-factors to tolerable levels. However, a number of undamped resonances with Q {ge} 10{sup 6} were found at 4 K and their mode identification remained as a goal for this paper. The approach taken here consists in taking different S{sub 21} measurements on a copper cavity replica of the ERL which can be compared with the actual data and also with Microwave Studio computer simulations. Several different S{sub 21} transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, between probes in a single cell, and between beam-position monitor probes in the beam tubes. Mode identification is supported by bead pulling with a metallic needle or a dielectric sphere that are calibrated in the fundamental mode. This paper presents results for HOMs in the first two dipole bands with the prototypical 958 MHz trapped mode, the lowest beam tube resonances, and high-Q modes in the first quadrupole band and beyond.

  14. Design of the beryllium window for Brookhaven Linac Isotope Producer

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Mapes, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Raparia, D. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-11-01

    In the Brookhaven Linac Isotope Producer (BLIP) beam line, there were two Beryllium (Be) windows with an air gap to separate the high vacuum upstream side from low vacuum downstream side. There had been frequent window failures in the past which affected the machine productivity and increased the radiation dose received by workers due to unplanned maintenance. To improve the window life, design of Be window is reexamined. Detailed structural and thermal simulations are carried out on Be window for different design parameters and loading conditions to come up with better design to improve the window life. The new design removed the air gap and connect the both beam lines with a Be window in-between. The new design has multiple advantages such as 1) reduces the beam energy loss (because of one window with no air gap), 2) reduces air activation due to nuclear radiation and 3) increased the machine reliability as there is no direct pressure load during operation. For quick replacement of this window, an aluminum bellow coupled with load binder was designed. There hasn’t been a single window failure since the new design was implemented in 2012.

  15. Design of the beryllium window for Brookhaven Linac Isotope Producer

    International Nuclear Information System (INIS)

    In the Brookhaven Linac Isotope Producer (BLIP) beam line, there were two Beryllium (Be) windows with an air gap to separate the high vacuum upstream side from low vacuum downstream side. There had been frequent window failures in the past which affected the machine productivity and increased the radiation dose received by workers due to unplanned maintenance. To improve the window life, design of Be window is reexamined. Detailed structural and thermal simulations are carried out on Be window for different design parameters and loading conditions to come up with better design to improve the window life. The new design removed the air gap and connect the both beam lines with a Be window in-between. The new design has multiple advantages such as 1) reduces the beam energy loss (because of one window with no air gap), 2) reduces air activation due to nuclear radiation and 3) increased the machine reliability as there is no direct pressure load during operation. For quick replacement of this window, an aluminum bellow coupled with load binder was designed. There hasn't been a single window failure since the new design was implemented in 2012.

  16. HOM identification by bead pulling in the Brookhaven ERL cavity

    CERN Document Server

    Hahn, H; Jain, Puneet; Johnson, Elliott C; Xu, Wencan

    2014-01-01

    Exploratory measurements of the Brookhaven Energy Recovery Linac (ERL) cavity at superconducting temperature produced a long list of high order modes (HOMs). The niobium 5-cell cavity is terminated at each end with HOM ferrite dampers that successfully reduce the Q-factors to levels required to avoid beam break up (BBU) instabilities. However, a number of un-damped resonances with Q≥106 were found at 4 K and their mode identification forms the focus of this paper. The approach taken here consists of bead pulling on a copper (Cu) replica of the ERL cavity with dampers involving various network analyzer measurements. Several different S21 transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, others between beam-position monitor probes in the beam tubes, and also between probes placed into the cells. The bead pull technique suitable for HOM identification with a metallic needle or dielectric bead is detailed. This paper presents the...

  17. Loading beryllium targets to extend the high flux isotope reactor's cycle length

    International Nuclear Information System (INIS)

    Various arrangements of beryllium loadings to create an internal neutron reflector in the flux trap region of the Oak Ridge National Laboratory's High Flux Isotope Reactor (HFIR) have been investigated. In particular, the impact upon fuel cycle length has been studied by performing calculations using the HFIR MCNP-based model HFV4.0. This study included examining perturbations in reactivity, flux, and power distribution caused by the various beryllium loadings. The HFIR Cycle 400 core configuration was used as a reference to calculate the impact of beryllium loadings upon cycle length. Three different configurations of beryllium loadings were investigated and compared against the Cycle 400 benchmark calculations; Cases 1 through 3 modeled combinations of 12 and 18 beryllium rods loaded into unused experimental sites. Calculated eigenvalues have shown that potential increases in reactivity between 0.56 and 0.79 dollars are attainable, depending on the various beryllium configurations. These results correspond to possible increases in fuel cycle length ranging between 2.3% and 3.3%. On the basis of their practicality, cost versus benefit, and greater potential for implementation, Cases 2 and 3 (both with 18 beryllium rods) were studied further and are herein reported in greater detail. Neutron flux distributions for Cases 2 and 3 were calculated at the horizontal mid-plane of the flux trap region, which showed no significant changes in the thermal flux magnitude and radial profile in comparison to Cycle 400. Likewise, safety analysis related parameters were contrasted, revealing power increments of up to 2% near the inside edge of the inner fuel element, well below the maximum acceptable value of 9%, a standing guideline employed for experiments at the HFIR. Additionally, the average neutron heat generation rate in beryllium rods and the maximum heat generation rate were evaluated to confirm that the design provides adequate coolant flow inside the rod and around the

  18. Response of materials to high heat fluxes during operation in fusion reactors

    International Nuclear Information System (INIS)

    Very high energy deposition on first wall and other components of a fusion reactor is expected due to plasma instabilities during both normal and off-normal operating conditions. Off-normal operating conditions result from plasma disruptions where the plasma loses confinement and dumps its energy on the reactor components. High heat flux may also result from normal operating conditions due to fluctuations in plasma edge conditions. This high energy dump in a short time results in very high surface temperatures and may consequently cause melting and vaporization of these materials. The net erosion rates resulting from melting and vaporization are very important to estimate the lifetime of such components. The response of different candidate materials to this high heat fluxes is determined for different energy densities and deposition times. The analysis used a previously developed model to solve the heat conduction equation in two moving boundaries. One moving boundary is at the surface to account for surface recession due to vaporization and the second moving boundary is to account for the solid-liquid interface inside the material. The calculations are done parametrically for both the expected energy deposited and the deposition time. These ranges of energy and time are based on recent experimental observations in current fusion devices. The candidate materials analyzed are stainless steel, carbon, and tungsten. 8 refs., 9 figs

  19. High heat flux actively cooled plasma facing components development, realization and first results in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Grosman, A. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

    2004-07-01

    The development, design, manufacture and testing of actively cooled high heat flux plasma facing components (PFC) has been an essential stage towards long powerful tokamak operations for Tore-Supra, it lasted about 10 years. This paper deals with the toroidal pumped limiter (TPL) that is able to sustain up to 10 MW/m{sup 2} of nominal heat flux. This device is based on hardened copper alloy heat sink structures covered by a carbon fiber composite armour, it resulted in the manufacturing of 600 elementary components, called finger elements, to achieve the 7.6 m{sup 2} TPL. This assembly has been operating in Tore-Supra since spring 2002. Some difficulties occurred during the manufacturing phase, the valuable industrial experience is summarized in the section 2. The permanent monitoring of PFC surface temperature all along the discharge is performed by a set of 6 actively cooled infrared endoscopes. The heat flux monitoring and control issue but also the progress made in our understanding of the deuterium retention in long discharges are described in the section 3. (A.C.)

  20. High heat flux actively cooled plasma facing components development, realization and first results in Tore Supra

    International Nuclear Information System (INIS)

    The development, design, manufacture and testing of actively cooled high heat flux plasma facing components (PFC) has been an essential stage towards long powerful tokamak operations for Tore-Supra, it lasted about 10 years. This paper deals with the toroidal pumped limiter (TPL) that is able to sustain up to 10 MW/m2 of nominal heat flux. This device is based on hardened copper alloy heat sink structures covered by a carbon fiber composite armour, it resulted in the manufacturing of 600 elementary components, called finger elements, to achieve the 7.6 m2 TPL. This assembly has been operating in Tore-Supra since spring 2002. Some difficulties occurred during the manufacturing phase, the valuable industrial experience is summarized in the section 2. The permanent monitoring of PFC surface temperature all along the discharge is performed by a set of 6 actively cooled infrared endoscopes. The heat flux monitoring and control issue but also the progress made in our understanding of the deuterium retention in long discharges are described in the section 3. (A.C.)

  1. Improved Gamma-Ray Flux Monitoring at the High Intensity Gamma-Ray Source (HIGS)

    Science.gov (United States)

    Reynolds, Robert

    2002-10-01

    An improved gamma-ray beam flux monitor has been built for use at the High Intensity Gamma-Ray Source at the Duke University Free Electron Laser Laboratories. It is important to know precisely the gamma-ray flux of this beam. It is also important to limit beam attenuation to a minimum while making an accurate flux measurement. The improvements from a more accurate gamma-ray intensity monitor will allow for more precise cross-section measurements and will be valuable to many of the experiments conducted at HIGS. The detector consists of a thin scintillator optically coupled to two photomultiplier tubes, a thin foil, and then another thin scintillator attached to two photomultiplier tubes. The front scintillator is used to veto counts from charged particles emitted upstream in the beam-line. The preliminary tests of the monitor show very promising results and after slight adjustments and calibrations, the detector will be ready to acquire accurate beam intensity measurements while contributing very little to beam attenuation.

  2. Surface modification of molten W exposed to high heat flux helium neutral beams

    International Nuclear Information System (INIS)

    High heat flux tests with central heat flux of 10.5 MW/m2 using helium neutral beams have been carried out on rolled tungsten. The energy of helium particles is 33 keV and the particle flux is 2 × 1021 m−2 s−1. An 80 × 65 × 3 mm3 rolled tungsten plate is firstly exposed to a 4.6 s pulse resulting in partially molten surfaces. Thereafter the tungsten plate is irradiated by several helium pulses with fluences of 1.2–2.5 × 1022/m2 and peak temperatures from 1450 to 2590 °C. The experiments show that: (1) helium-induced surface modification of the resolidified tungsten surface is very different from that of the non-molten surface; (2) the surface morphology of molten surface is closely related to the orientation of the resolidified grain; (3) the evolution of surface modifications, for both of the molten and non-molten tungsten surfaces, indicates a strong dependence on the surface temperature and local helium fluence

  3. Experimental and analytical studies of high heat flux components for fusion experimental reactor

    International Nuclear Information System (INIS)

    In this report, the experimental and analytical results concerning the development of plasma facing components of ITER are described. With respect to developing high heat removal structures for the divertor plates, an externally-finned swirl tube was developed based on the results of critical heat flux (CHF) experiments on various tube structures. As the result, the burnout heat flux, which also indicates incident CHF, of 41 ± 1 MW/m2 was achieved in the externally-finned swirl tube. The applicability of existing CHF correlations based on uniform heating conditions was evaluated by comparing the CHF experimental data with the smooth and the externally-finned tubes under one-sided heating condition. As the results, experimentally determined CHF data for straight tube show good agreement, for the externally-finned tube, no existing correlations are available for prediction of the CHF. With respect to the evaluation of the bonds between carbon-based material and heat sink metal, results of brazing tests were compared with the analytical results by three dimensional model with temperature-dependent thermal and mechanical properties. Analytical results showed that residual stresses from brazing can be estimated by the analytical three directional stress values instead of the equivalent stress value applied. In the analytical study on the separatrix sweeping for effectively reducing surface heat fluxes on the divertor plate, thermal response of the divertor plate has been analyzed under ITER relevant heat flux conditions and has been tested. As the result, it has been demonstrated that application of the sweeping technique is very effective for improvement in the power handling capability of the divertor plate and that the divertor mock-up has withstood a large number of additional cyclic heat loads. (J.P.N.) 62 refs

  4. Methane fluxes in the high northern latitudes estimated using a Bayesian atmospheric inversion

    Science.gov (United States)

    Thompson, Rona; Stohl, Andreas; Myhre, Cathrine Lund; Sasakawa, Motoki; Machida, Toshinobu; Aalto, Tuula; Dlugokencky, Edward; Worthy, Douglas; Skorokhod, Andrey

    2016-04-01

    Methane (CH4) is the second most important anthropogenic greenhouse gas after CO2. Atmospheric CH4 increased from pre-industrial concentrations of around 850 ppb (parts-per-billion) to 1773 ppb in the late 1990s and then remained approximately stable until the mid 2000s. However, since 2006 atmospheric CH4 has begun to increase again. The reasons for the stabilization and subsequent increase are likely to be a combination of changes in anthropogenic emissions such as from fossil fuels, as well as natural wetland sources. While global atmospheric inversions indicate that natural wetland sources in the tropics and subtropics have contributed to the recent increase, land surface and ecosystem models generally indicate no increase in these sources. Another potential source for the change in CH4 concentration could be wetlands in the high northern latitudes, which comprise about 44% of global wetland area. These latitudes are also undergoing rapid warming, which will impact wetland emissions of CH4. We present CH4 fluxes for the high northern latitudes (>50°N) from 2005 to 2012 estimated from a Bayesian atmospheric inversion. The inversion incorporates observations from 17 in-situ and 6 discrete-sample sites across North America and Northern Eurasia. Atmospheric transport is based on the Lagrangian particle dispersion model, FLEXPART, run with ECMWF meteorological analyses. Emissions were optimized monthly and on a spatial grid of variable resolution (from 1°×1° to 4°×4°). Background concentrations were estimated by coupling FLEXPART to monthly global 2-D fields of CH4 concentration from a bivariate interpolation of smoothed data from the NOAA ESRL network. We estimate the total mean North American flux (>50°N) to be 18 -- 27 Tg y-1, and the total mean Northern Eurasian flux (>50°N) to be 55 -- 66 Tg y-1, both substantially higher than the prior (based on LPX-Bern for wetland and EDGAR-4.2FT2010 for anthropogenic fluxes). We also find a small trend in the

  5. Compton scattering for spectroscopic detection of ultra-fast, high flux, broad energy range X-rays

    International Nuclear Information System (INIS)

    Compton side-scattering has been used to simultaneously downshift the energy of keV to MeV energy range photons while attenuating their flux to enable single-shot, spectrally resolved, measurements of high flux X-ray sources to be undertaken. To demonstrate the technique a 1 mm thick pixelated cadmium telluride detector has been used to measure spectra of Compton side-scattered radiation from a Cobalt-60 laboratory source and a high flux, high peak brilliance X-ray source of betatron radiation from a laser-plasma wakefield accelerator

  6. A High-Flux, Flexible Membrane with Parylene-encapsulated Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Park, H G; In, J; Kim, S; Fornasiero, F; Holt, J K; Grigoropoulos, C P; Noy, A; Bakajin, O

    2008-03-14

    We present fabrication and characterization of a membrane based on carbon nanotubes (CNTs) and parylene. Carbon nanotubes have shown orders of magnitude enhancement in gas and water permeability compared to estimates generated by conventional theories [1, 2]. Large area membranes that exhibit flux enhancement characteristics of carbon nanotubes may provide an economical solution to a variety of technologies including water desalination [3] and gas sequestration [4]. We report a novel method of making carbon nanotube-based, robust membranes with large areas. A vertically aligned dense carbon nanotube array is infiltrated with parylene. Parylene polymer creates a pinhole free transparent film by exhibiting high surface conformity and excellent crevice penetration. Using this moisture-, chemical- and solvent-resistant polymer creates carbon nanotube membranes that promise to exhibit high stability and biocompatibility. CNT membranes are formed by releasing a free-standing film that consists of parylene-infiltrated CNTs, followed by CNT uncapping on both sides of the composite material. Thus fabricated membranes show flexibility and ductility due to the parylene matrix material, as well as high permeability attributed to embedded carbon nanotubes. These membranes have a potential for applications that may require high flux, flexibility and durability.

  7. Resolving mass flux at high spatial and temporal resolution using GRACE intersatellite measurements

    DEFF Research Database (Denmark)

    Rowlands, D. D.; Luthcke, S. B.; Klosko, S. M.; Lemoine, F. G. R.; Chinn, D. S.; McCarthy, J. J.; Cox, C. M.; Andersen, Ole Baltazar

    2005-01-01

    The GRACE mission is designed to monitor mass flux on the Earth's surface at one month and high spatial resolution through the estimation of monthly gravity fields. Although this approach has been largely successful, information at submonthly time scales can be lost or even aliased through the es...... resolution. Using 4° × 4° blocks at 10-day intervals, we estimate the mass of surplus or deficit water over a 52° × 60° grid centered on the Amazon basin for July 2003. We demonstrate that the recovered signals are coherent and correlate well with the expected hydrological signal....

  8. Giant flux creep through surface barriers and the irreversibility line in high-temperature superconductors

    International Nuclear Information System (INIS)

    Magnetic and transport phenomena in high-temperature superconductors due to magnetic flux relaxation and transport over the surface barrier are investigated. Vortex dynamics controlled by the penetration both of pancake vortices and vortex lines is discussed. The penetration field Hp for pancakes decays exponentially with temperature. The size of the magnetization loop is determined by the decay of Hp during the process of relaxation, but its shape remains unchanged. The irreversibility line associated with the pancake penetration is given by Hirr ∝exp(-2T/T0) and may lie both above and below the melting line

  9. High-Flux Beamline for Ultraviolet and Vacuum-Ultraviolet Circular Dichroism at NSRL

    International Nuclear Information System (INIS)

    This paper describes the commissioning and characterization of an NSRL bending magnet beamline constructed for the measurement of vacuum-ultraviolet circular dichroism on biological and other materials. The beamline provides high fluxes of ultraviolet and vacuum-ultraviolet radiation, which is converted into plane polarized light using a polarizer and subsequently converted into circularly polarized light using a photoelastic modulator with a switching frequency of 50 kHz. The beamline has the best wavelength resolution of 0.3 nm and stray light levels better than 0.03%. Example spectra of (1s)-(+)-10-camphorsulphonic acid (CSA) and myoglobin are given

  10. Magnetization and flux pinning in high-Tc cuprates: Irradiated and oxygen deficient materials

    International Nuclear Information System (INIS)

    This work surveys recent studies of the intragrain current density J and vortex pinning in high Tc superconductors. Materials include Y1Ba2Cu3O7-δ and Bi2Sr2Ca1Cu2O8 single crystals and aligned polycrystals. To probe the flux pinning, we modified the strength, number, and morphology of defects. Varying the oxygen content (7-δ) in YBa2Cu3O7-δ or irradiating the materials with ions, having either light or heavy masses, gives systematic changes in the character of the all-important defects

  11. EPR detection of the flux distribution in ceramic high-T c superconductors

    Science.gov (United States)

    Rakvin, B.; Požek, M.; Dulčić, A.

    1989-10-01

    EPR measurements were made on adsorbed diphenyl picrylhydrazil (DPPH) at the surface of a ceramic high- T c superconductor YBa 2Cu 3O 7. A significant broadening of the EPR linewidth was observed below the superconducting transition temperature T c. It is interpreted as a broadening due to the spatial distribution of the flux in the superconducting mixed state which is developed at the resonant magnetic field H 0 (H Cl ≪ H 0 ≪ H C2). The penetration depth of the magnetic field can be determined by this simple technique.

  12. Burnout in a high heat-flux boiling system with an impinging jet

    International Nuclear Information System (INIS)

    An experimental study has been made on the fully-developed nucleate boiling at atmospheric pressure in a simple forced-convection boiling system, which consists of a heated flat surface and a small, high-speed jet of water or of freon-113 impinging on the heated surface. A generalized correlation for burnout heat flux data, that is applied to either water or freon-113 is successfully evolved, and it is shown that surface tension has an important role for the onset of burnout phenomenon, not only in the ordinary pool boiling, but also in the present boiling system with a forced flow. (author)

  13. The impact of nebular emission on the broadband fluxes of high-redshift galaxies

    CERN Document Server

    Zackrisson, E; Leitet, E

    2008-01-01

    A substantial fraction of the light emitted from young or star-forming galaxies at ultraviolet to near-infrared wavelengths comes from the ionized interstellar medium in the form of emission lines and a nebular continuum. At high redshifts, star formation rates are on average higher and stellar populations younger than in the local Universe. Both of these effects act to boost the impact of nebular emission on the overall spectrum of galaxies. Even so, the broadband fluxes and colours of high-redshift galaxies are routinely analyzed under the assumption that the light observed originates directly from stars. Here, we assess the impact of nebular emission on broadband fluxes in Johnson/Cousins BVRIJHK, Sloan Digital Sky Survey griz and Spitzer IRAC/MIPS filters as a function of observed redshift (up to z=15) for galaxies with different star formation histories. We find that nebular emission may account for a non-negligible fraction of the light received from high-redshift galaxies. The ages and masses inferred ...

  14. Ultra-high energy cosmic rays and the extragalactic gamma ray flux

    CERN Document Server

    Erlykin, A D

    2014-01-01

    Ultra-high energy cosmic rays interacting with the radiation fields in the universe cause electromagnetic cascades resulting in a flux of extragalactic gamma rays, detectable to some 100 GeV. Recent precise measurements of the extragalactic gamma ray flux by Fermi-LAT, coupled with estimates of the background from active galactic nuclei of various types, allows limits to be set on the cascade component. By comparison with prediction and, making various assumptions, ie taking a particular model, limits can be set on the maximum energy to which ultra-high energy particle can be accelerated. If our model is correct, it is unlikely that the maximum energy is above 100 EeV, in turn, the apparent 'GZK' cut-off in the measured ultra-high energy spectrum could instead be due to a fall-off in the intrinsic emergent particle spectrum. However, it is not plausible to be dogmatic at the present time because of uncertainty in many of the parameters involved. We have used recent estimates of the range of parameters and hav...

  15. Total Reflection X-ray Fluorescence Analysis (TXRF) using the high flux SAXS camera

    CERN Document Server

    Wobrauschek, P; Pepponi, G; Bergmann, A; Glatter, O

    2002-01-01

    Combining the high photon flux from a rotating anode X-ray tube with an X-ray optical component to focus and monochromatize the X-ray beam is the most promising instrumentation for best detection limits in the modern XRF laboratory. This is realized by using the design of a high flux SAXS camera in combination with a 4 kW high brilliant rotating Cu anode X-ray tube with a graded elliptically bent multilayer and including a new designed module for excitation in total reflection geometry within the beam path. The system can be evacuated thus reducing absorption and scattering of air and removing the argon peak in the spectra. Another novelty is the use of a Peltier cooled drift detector with an energy resolution of 148 eV at 5.9 keV and 5 mm sup 2 area. For Co detection limits of about 300 fg determined by a single element standard have been achieved. Testing a real sample NIST 1643d led to detection limits in the range of 300 ng/l for the medium Z.

  16. Toward an estimation of daily european CO2 fluxes at high spatial resolution by inversion of atmospheric transport

    International Nuclear Information System (INIS)

    over Europe. To study the potential of this method, we used synthetic data generated from forward simulations of LMDZt (driven by flux fields generated from the biosphere model ORCHIDEE). We have found that the current network is not dense enough to constrain fluxes at model resolution. However, fluxes that are aggregated spatially over a region of 850 x 850 km in the Western Europe and temporally over 8-10 days compare very well with the ORCHIDEE fluxes. Preliminary inversion results using real data indicate that synoptic variations of estimated fluxes are in phase with the variations of the ORCHIDEE biosphere model flux and the variations observed in atmospheric concentrations. However, the quality of the flux estimates are highly dependant on transport model errors and in particular, on the quality of modelling small scale transport. Moreover, fossil fuel emissions are prescribed in this inverse model and the quality of their distribution is shown to be crucial. Data selection also has a large impact on estimated fluxes. The use of the daytime only data to calculate daily averaged concentrations greatly improves the estimated fluxes by reducing bias inferred from model transport errors. (author)

  17. Clinical evaluation of four different high-flux hemodialyzers under conventional conditions in vivo.

    Science.gov (United States)

    Sombolos, K; Tsitamidou, Z; Kyriazis, G; Karagianni, A; Kantaropoulou, M; Progia, E

    1997-01-01

    Four types of high-flux hemodialyzers, Primus 2000 (high-flux polysulfone 2.0 m2), Altra-Flux 170 G (cellulose diacetate 1.7 m2), FLX-15 GW (polyester-polymer alloy 1.5 m2) and PAN-85 DX (polyacrylonitrile 1.7 m2) were evaluated in vivo. A total of 12 stable chronic hemodialysis patients participated in the study and each type of dialyzer was tested once in 9 of them. Blood samples for the measurement of BUN, creatinine, phosphate, uric acid, albumin and beta2-microglobulin (beta2M) were drawn before and 5 min after the end of the study dialysis. During dialysis, which was performed in all patients with a blood flow rate of 250 ml/min for 240 min, the dialysate (550-600 ml/min) was collected every hour and samples were drawn for the measurements of all the above substances. The mean total amount of low-molecular substances removed per session by each dialyzer was very close to 19.5 g for urea, 2.0 g for creatinine, 0.9 g for phosphate and 1 g for uric acid. The one-third (30-33%) of the above amounts were removed during the first hour of dialysis. Dialyzers' clearances for creatinine and uric acid were significantly higher in Primus dialyzer comparing to FLX-15 GW (p borderline significance (p = 0.055). No difference was found either among Altra-Flux 170 G, FLX-15 GW and PAN-85 DX or between Primus and PAN-85 DX dialyzers. Phosphate clearance did not show any difference among the four dialyzers. The lowest amount of albumin removed per session was 0.75 g by PAN-85 DX and the highest 1.8 g by FLX-15 GW, while the equivalents for beta2M were 80 mg by Altra-Flux 170 G and 142 mg by PAN-85 DX. A significant adsorption of beta2M on these dialysis membranes was indicated by the combination of a satisfactory serum beta2M reduction ratio (post-/predialysis values = 0.52, 0.77, 0.60, 0.55) with a reduced beta2M clearance (23.9, 13.6, 20.2, 25.1 ml/min). During the first hour of dialysis, in comparison to the following time, the highest amounts of albumin and beta2M

  18. A high sensitivity momentum flux measuring instrument for plasma thruster exhausts and diffusive plasmas

    International Nuclear Information System (INIS)

    A high sensitivity momentum flux measuring instrument based on a compound pendulum has been developed for use with electric propulsion devices and radio frequency driven plasmas. A laser displacement system, which builds upon techniques used by the materials science community for surface stress measurements, is used to measure with high sensitivity the displacement of a target plate placed in a plasma thruster exhaust. The instrument has been installed inside a vacuum chamber and calibrated via two different methods and is able to measure forces in the range of 0.02-0.5 mN with a resolution of 15 μN. Measurements have been made of the force produced from the cold gas flow and with a discharge ignited using argon propellant. The plasma is generated using a Helicon Double Layer Thruster prototype. The instrument target is placed about 1 mean free path for ion-neutral charge exchange collisions downstream of the thruster exit. At this position, the plasma consists of a low density ion beam (10%) and a much larger downstream component (90%). The results are in good agreement with those determined from the plasma parameters measured with diagnostic probes. Measurements at various flow rates show that variations in ion beam velocity and plasma density and the resulting momentum flux can be measured with this instrument. The instrument target is a simple, low cost device, and since the laser displacement system used is located outside the vacuum chamber, the measurement technique is free from radio frequency interference and thermal effects. It could be used to measure the thrust in the exhaust of other electric propulsion devices and the momentum flux of ion beams formed by expanding plasmas or fusion experiments.

  19. HIGH TEMPERATURE EROSION WEAR OF CERMET PARTICLES REINFORCED SELF-FLUXING ALLOY MATRIX HVOF SPRAYED COATINGS

    Directory of Open Access Journals (Sweden)

    Andrei Surzhenkov

    2015-09-01

    Full Text Available In the present paper, the resistance of high velocity oxy-fuel (HVOF sprayed TiC-NiMo and Cr3C2-Ni cermet particles reinforced NiCrSiB self-fluxing alloy matrix coatings to high temperature erosion wear is studied. Microstructure of the coatings was examined by SEM, phase composition was determined by XRD. A four-channel centrifugal particle accelerator was applied to study the high temperature erosion wear of the coatings. The impact angles were 30 and 90 degrees, initial particle velocity was 50 m/s, temperature of the test - 650 degrees. Volume wear of the coatings was calculated and compared to the respective values of the reference materials. Wear mechanisms were studied by SEM.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7617

  20. Calibration of high-heat-flux sensors in a solar furnace

    International Nuclear Information System (INIS)

    The most common sensors used for the measurement of high solar irradiance are the Gardon gauges, which are usually calibrated using a black body at a certain temperature as the radiant source. This calibration procedure is assumed to produce a systematic error when solar irradiance measurements are taken using these sensors. This paper demonstrates a calorimetric method for calibrating these high-heat-flux gauges in a solar furnace. This procedure has enabled these sensors to be calibrated under concentrated solar radiation at higher irradiances under non-laboratory conditions in the CIEMAT solar furnace at the Plataforma Solar de Almeria. Working at higher irradiances has allowed the uncertainty in the calibration constant of these sensors to be reduced. This work experimentally confirms the predicted systematic errors committed when measuring high solar irradiances using Gardon sensors calibrated with a black body. (authors)

  1. High-energy neutrino fluxes from AGN populations inferred from X-ray surveys

    CERN Document Server

    Jacobsen, Idunn B; On, Alvina Y L; Saxton, Curtis J

    2015-01-01

    High-energy neutrinos and photons are complementary messengers, probing violent astrophysical processes and structural evolution of the Universe. X-ray and neutrino observations jointly constrain conditions in active galactic nuclei (AGN) jets: their baryonic and leptonic contents, and particle production efficiency. Testing two standard neutrino production models for local source Cen A \\citep{KT2008,BB2009}, we calculate the high-energy neutrino spectra of single AGN sources and derive the flux of high-energy neutrinos expected for the current epoch. Assuming that accretion determines both X-rays and particle creation, our parametric scaling relations predict neutrino yield in various AGN classes. We derive redshift-dependent number densities of each class, from {\\it Chandra} and {\\it Swift}/BAT X-ray luminosity functions \\citep{SGB2008,ACS2009}. We integrate the neutrino spectrum expected from the cumulative history of AGN (correcting for cosmological and source effects, e.g. jet orientation and beaming). B...

  2. Modeling of a heat sink and high heat flux vapor chamber

    Science.gov (United States)

    Vadnjal, Aleksander

    An increasing demand for a higher heat flux removal capability within a smaller volume for high power electronics led us to focus on a novel cold plate design. A high heat flux evaporator and micro channel heat sink are the main components of a cold plate which is capable of removing couple of 100 W/cm2. In order to describe performance of such porous media device a proper modeling has to be addressed. A universal approach based on the volume average theory (VAT) to transport phenomena in porous media is shown. An approach on how to treat the closure for momentum and energy equations is addressed and a proper definition for friction factors and heat transfer coefficients are discussed. A numerical scheme using a solution to Navier-Stokes equations over a representative elementary volume (REV) and the use of VAT is developed to show how to compute friction factors and heat transfer coefficients. The calculation show good agreement with the experimental data. For the heat transfer coefficient closure, a proper average for both fluid and solid is investigated. Different types of heating are also investigated in order to determine how it influences the heat transfer coefficient. A higher heat fluxes in small area condensers led us to the micro channels in contrast to the classical heat fin design. A micro channel can have various shapes to enhance heat transfer, but the shape that will lead to a higher heat flux removal with a moderate pumping power needs to be determined. The standard micro-channel terminology is usually used for channels with a simple cross section, e.g. square, round, triangle, etc., but here the micro channel cross section is going to be expanded to describe more complicated and interconnected micro scale channel cross sections. The micro channel geometries explored are pin fins (in-line and staggered) and sintered porous micro channels. The problem solved here is a conjugate problem involving two heat transfer mechanisms; (1) porous media

  3. Development of candidate high heat flux components for steady state operation of the EAST device

    International Nuclear Information System (INIS)

    EAST is a full superconducting tokamak, as a National project in ASIPP, which will operate in high power and steady state, and impose severe requirements on plasma facing components (PFC). There are three aspects important: 1) PFM has high enough thermal conductivity, which can fulfill the criteria to exhaust the high power deposit on PFC and can meet the requirements of surface temperature constraints; 2) Erosion resistance is also very important, which directly related to the lifetime of plasma facing components and plasma recycling control. 3) Integration behavior of PFC under actively water-cooled conditions. A series of multi-element doped graphite has been developed for the first wall, and a super carbon sheet has been chosen as compliant layer to improve the thermal contact and minimize the surface temperature; Contrary to CBM, SiC has much lower chemical and high-temperature sputtering, is capable of oxygen gettering and lower hydrogen recycling. The behavior of thick SiC gradient coatings on different CBM under steady state and pulsed high heat flux, and HT-7 limiter plasma irradiation was investigated. Tungsten is now under development being considered as one of the promising candidate materials for the divertor plate of EAST device, several joining Methods have been developed, 2mm thick tungsten tile brazed or direct by blast compound to copper alloy heat sink with functionally gradient layer, a modeling for residual stress analysis has been established and high heat flux experiments have also been finished, a small mock-up possess good performance, a large module is now under way. In the above experiments, the samples were examined with respect to the temperature distribution, changes of surface morphology, surface atomic composition and etc. (authors)

  4. Monitoring Delamination of Thermal Barrier Coatings During Interrupted High-Heat-Flux Laser Testing using Luminescence Imaging

    Science.gov (United States)

    Eldridge, Jeffrey I.; Zhu, Dongming; Wolfe, Douglas E.

    2011-01-01

    This presentation showed progress made in extending luminescence-base delamination monitoring to TBCs exposed to high heat fluxes, which is an environment that much better simulates actual turbine engine conditions. This was done by performing upconversion luminescence imaging during interruptions in laser testing, where a high-power CO2 laser was employed to create the desired heat flux. Upconverison luminescence refers to luminescence where the emission is at a higher energy (shorter wavelength) than the excitation. Since there will be negligible background emission at higher energies than the excitation, this methods produces superb contrast. Delamination contrast is produced because both the excitation and emission wavelengths are reflected at delamination cracks so that substantially higher luminescence intensity is observed in regions containing delamination cracks. Erbium was selected as the dopant for luminescence specifically because it exhibits upconversion luminescence. The high power CO2 10.6 micron wavelength laser facility at NASA GRC was used to produce the heat flux in combination with forced air backside cooling. Testing was performed at a lower (95 W/sq cm) and higher (125 W/sq cm) heat flux as well as furnace cycling at 1163C for comparison. The lower heat flux showed the same general behavior as furnace cycling, a gradual, "spotty" increase in luminescence associated with debond progression; however, a significant difference was a pronounced incubation period followed by acceleration delamination progression. These results indicate that extrapolating behavior from furnace cycling measurements will grossly overestimate remaining life under high heat flux conditions. The higher heat flux results were not only accelerated, but much different in character. Extreme bond coat rumpling occurred, and delamination propagation extended over much larger areas before precipitating macroscopic TBC failure. This indicates that under the higher heat flux (and

  5. Soil CO2 flux and photoautotrophic community composition in high-elevation, 'barren' soil.

    Science.gov (United States)

    Freeman, Kristen R; Pescador, Monte Y; Reed, Sasha C; Costello, Elizabeth K; Robeson, Michael S; Schmidt, Steven K

    2009-03-01

    Soil-dominated ecosystems, with little or no plant cover (i.e. deserts, polar regions, high-elevation areas and zones of glacial retreat), are often described as 'barren', despite their potential to host photoautotrophic microbial communities. In high-elevation, subnival zone soil (i.e. elevations higher than the zone of continuous vegetation), the structure and function of these photoautotrophic microbial communities remains essentially unknown. We measured soil CO(2) flux at three sites (above 3600 m) and used molecular techniques to determine the composition and distribution of soil photoautotrophs in the Colorado Front Range. Soil CO(2) flux data from 2002 and 2007 indicate that light-driven CO(2) uptake occurred on most dates. A diverse community of Cyanobacteria, Chloroflexi and eukaryotic algae was present in the top 2 cm of the soil, whereas these clades were nearly absent in deeper soils (2-4 cm). Cyanobacterial communities were composed of lineages most closely related to Microcoleus vaginatus and Phormidium murrayi, eukaryotic photoautotrophs were dominated by green algae, and three novel clades of Chloroflexi were also abundant in the surface soil. During the light hours of the 2007 snow-free measurement period, CO(2) uptake was conservatively estimated to be 23.7 g C m(-2) season(-1). Our study reveals that photoautotrophic microbial communities play an important role in the biogeochemical cycling of subnival zone soil. PMID:19187281

  6. High Resolution Modeling of Anthropogenic and Biogenic Carbon Dioxide Fluxes From the Portland Oregon Metropolitan Area

    Science.gov (United States)

    Butenhoff, C. L.; Powell, J.; Tran, D.; Rice, A. L.

    2013-12-01

    The future of the North American carbon cycle is heavily dependent on urban ecosystems and their development. Around 75-80% of the current U.S. population is urbanized and this percentage is likely to increase in the future. Despite the lack of national climate policy, cities nationwide are developing their own plans to reduce carbon dioxide (CO2) emissions. The city of Portland OR for example (along with Multnomah County) has in place an ambitious goal of reducing CO2 emissions by 80% by the year 2050. Monitoring and verifying emission reductions will be integral to the successful operation of this and other mitigation policies. To do so requires both the modeling and measurement of CO2 at high spatial and temporal resolution. To this effort we developed gridded inventories of anthropogenic and biogenic fluxes of CO2 from Portland and the surrounding metropolitan region at 1-km resolution and at hourly time steps. Mobile emissions were estimated using traffic count data, a land-use regression model, and the EPA MOVES model. Biogenic fluxes of CO2 were calculated using high resolution remote sensing vegetation maps and the Vegetation Photosynthesis and Respiration Model coupled to the Weather Research and Forecasting Model (WRF-VPRM). This is part of an on-going effort to constrain emission estimates using measurements of CO2 from throughout the region. Here we compare simulated concentrations of CO2 with data available from three sites, representing upwind, downwind, and city center conditions.

  7. ANL ITER high-heat-flux blanket-module heat transfer experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kasza, K.E.

    1992-02-01

    An Argonne National Laboratory facility for conducting tests on multilayered slab models of fusion blanket designs is being developed; some of its features are described. This facility will allow testing under prototypic high heat fluxes, high temperatures, thermal gradients, and variable mechanical loadings in a helium gas environment. Steady and transient heat flux tests are possible. Electrical heating by a two-sided, thin stainless steel (SS) plate electrical resistance heater and SS water-cooled cold panels placed symmetrically on both sides of the heater allow achievement of global one-dimensional heat transfer across blanket specimen layers sandwiched between the hot and cold plates. The heat transfer characteristics at interfaces, as well as macroscale and microscale thermomechanical interactions between layers, can be studied in support of the ITER engineering design effort. The engineering design of the test apparatus has shown that it is important to use multidimensional thermomechanical analysis of sandwich-type composites to adequately analyze heat transfer. This fact will also be true for the engineering design of ITER.

  8. ANL ITER high-heat-flux blanket-module heat transfer experiments. Fusion Power Program

    Energy Technology Data Exchange (ETDEWEB)

    Kasza, K.E.

    1992-02-01

    An Argonne National Laboratory facility for conducting tests on multilayered slab models of fusion blanket designs is being developed; some of its features are described. This facility will allow testing under prototypic high heat fluxes, high temperatures, thermal gradients, and variable mechanical loadings in a helium gas environment. Steady and transient heat flux tests are possible. Electrical heating by a two-sided, thin stainless steel (SS) plate electrical resistance heater and SS water-cooled cold panels placed symmetrically on both sides of the heater allow achievement of global one-dimensional heat transfer across blanket specimen layers sandwiched between the hot and cold plates. The heat transfer characteristics at interfaces, as well as macroscale and microscale thermomechanical interactions between layers, can be studied in support of the ITER engineering design effort. The engineering design of the test apparatus has shown that it is important to use multidimensional thermomechanical analysis of sandwich-type composites to adequately analyze heat transfer. This fact will also be true for the engineering design of ITER.

  9. Microsystem for remote sensing of high energy radiation with associated extremely low photon flux densities

    Science.gov (United States)

    Otten, A.; Jain, V. K.

    2015-08-01

    This paper presents a microsystem for remote sensing of high energy radiation in extremely low flux density conditions. With wide deployment in mind, potential applications range from nuclear non-proliferation, to hospital radiation-safety. The daunting challenge is the low level of photon flux densities - emerging from a Scintillation Crystal (SC) on to a ~1 mm-square detector, which are a factor of 10000 or so lower than those acceptable to recently reported photonic chips (including `single-photon detection' chips), due to a combination of low Lux, small detector size, and short duration SC output pulses - on the order of 1 μs. These challenges are attempted to be overcome by the design of an innovative `System on a Chip' type microchip, with high detector sensitivity, and effective coupling from the SC to the photodetector. The microchip houses a tiny n+ diff p-epi photodiode (PD) as well as the associated analog amplification and other related circuitry, all fabricated in 0.5micron, 3-metal 2-poly CMOS technology. The amplification, together with pulse-shaping of the photocurrent-induced voltage signal, is achieved through a tandem of two capacitively coupled, double-cascode amplifiers. Included in the paper are theoretical estimates and experimental results.

  10. 7Be(p, γ)8B and the high-energy solar neutrino flux

    International Nuclear Information System (INIS)

    Despite thirty years of extensive experimental and theoretical work, the predicted solar neutrino flux is still in sharp disagreement with measurements. The solar neutrino measurements strongly suggest that the problem cannot be solved within the standard electroweak and astrophysical theories. Thus, the solar neutrino problem constitutes the strongest evidence for physics beyond the Standard Model. Whatever the solution of the solar neutrino problem turns out to be, it is of paramount importance that the input parameters of the underlying electroweak and solar theories rest upon solid ground. The most uncertain nuclear input parameter in standard solar models is the low-energy 7Be(p, γ)8B radiative capture cross section. This reaction produces 8B in the Sun, whose β+ decay is the main source of the high-energy solar neutrinos. Here, the importance of the 7Be(p, γ)8B reaction in predicting the high energy solar neutrino flux is discussed. The author presents a microscopic eight-body model and a potential model for the calculation of the 7Be(p, γ)8B cross section

  11. Novel polymer derived ceramic-high temperature heat flux sensor for gas turbine environment

    Science.gov (United States)

    Nagaiah, N. R.; Kapat, J. S.; An, L.; Chow, L.

    2006-04-01

    This paper attempts to prove the feasibility of a novel High Temperature Heat Flux (HTHF) sensor for gas turbine environment. Based on the latest improvement in a new type of Polymer-Derived Ceramic (PDC) material, the authors present the design and development of a HTHF sensor based on PDC material, and show that such a sensor is indeed feasible. The PDC-HTHF sensor is fabricated using newly developed polymer derived SiCN, whose conductivity is controlled by proper composition and treatment condition. Direct measurements and characterization of the relevant material properties are presented. Electrical conductivity can be varied from 0 (insulator) to 100 (ohm.cm)-1; in addition a value of 4000 ppm/°C (at 600 K) is obtained for temperature coefficient of resistance. This novel sensor is found to perform quite satisfactorily at about 1400 °C for long term as compared to conventional heat flux sensors available commercially. This type of PDC-HTHF sensor can be used in harsh environments due to its high temperature resistance and resistance to oxidation. This paper also discusses lithography as a microfabrication technique to manufacture the proposed PDC-HTHF sensor. In our current design, the sensor dimensions are 2.5mm in diameter and 250 µm thickness.

  12. Novel polymer derived ceramic-high temperature heat flux sensor for gas turbine environment

    International Nuclear Information System (INIS)

    This paper attempts to prove the feasibility of a novel High Temperature Heat Flux (HTHF) sensor for gas turbine environment. Based on the latest improvement in a new type of Polymer-Derived Ceramic (PDC) material, the authors present the design and development of a HTHF sensor based on PDC material, and show that such a sensor is indeed feasible. The PDC-HTHF sensor is fabricated using newly developed polymer derived SiCN, whose conductivity is controlled by proper composition and treatment condition. Direct measurements and characterization of the relevant material properties are presented. Electrical conductivity can be varied from 0 (insulator) to 100 (ohm.cm)-1; in addition a value of 4000 ppm/0C (at 600 K) is obtained for temperature coefficient of resistance. This novel sensor is found to perform quite satisfactorily at about 1400 0C for long term as compared to conventional heat flux sensors available commercially. This type of PDC-HTHF sensor can be used in harsh environments due to its high temperature resistance and resistance to oxidation. This paper also discusses lithography as a microfabrication technique to manufacture the proposed PDC-HTHF sensor. In our current design, the sensor dimensions are 2.5mm in diameter and 250 μm thickness

  13. Estimation of HFIR [High-Flux Isotope Reactor] core flow rate using a back propagation network

    International Nuclear Information System (INIS)

    The corrosion of aluminum dispersion fuel of Oak Ridge National Laboratory's High-Flux Isotope Reactor (HFIR) has recently been under review. The surface temperature of the fuel under high-flux conditions increases as the oxide layer grows or crud deposits on the fuel. This additional temperature rise in turn speeds the oxide buildup creating an unstable situation. Since the low thermal conductivity of the corrosion product film may compromise the thermal limits of the reactor, and also, erosion of the aluminum plates may lead to leakage of fission products from the plates, a careful monitoring of corrosion would be useful for the HFIR. In addition, an examination of HFIR operating data indicates that excessive corrosion has a noticeable effect on core flow rate and pressure drop. Typically, as the thickness of oxide layer increases, the flow rate gradually decreases and the pressure drop increases; therefore, it has been recommended that the core pressure drop and flow characteristics be monitored during each fuel cycle. The purpose of this study is to investigate the feasibility of applying neural networks to predict the flow rate in the HFIR core using a set of other HFIR operating data. The back propagation network (BPN) is a multilayer, fully connected heteroassociative network. During the training stage, the BPN learning algorithm computes the weights between pairs such that the difference between the actual output and the network output is minimized in a least-squares sense

  14. IFMIF High Flux Test Module-Recent progress in design and manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Leichtle, D. [Association FZK-EURATOM, Forschungszentrum Karlsruhe, Institut fuer Reaktorsicherheit, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)], E-mail: leichtle@irs.fzk.de; Arbeiter, F.; Dolensky, B.; Fischer, U.; Gordeev, S.; Heinzel, V.; Ihli, T.; Lang, K.-H. [Association FZK-EURATOM, Forschungszentrum Karlsruhe, Institut fuer Reaktorsicherheit, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Moeslang, A. [Association FZK-EURATOM, Forschungszentrum Karlsruhe, Institut fuer Materialforschung, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Simakov, S.P.; Slobodchuk, V.; Stratmanns, E. [Association FZK-EURATOM, Forschungszentrum Karlsruhe, Institut fuer Reaktorsicherheit, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2008-12-15

    The International Fusion Material Irradiation Facility (IFMIF) is an accelerator driven neutron source for irradiation tests of candidate fusion reactor materials. Within the High Flux Test Module (HFTM) a testing volume of 0.5 l filled by qualified small scale specimens will be irradiated at displacement rates of 20-50 dpa/fpy in structural materials. The Forschungszentrum Karlsruhe (FZK) has developed a HFTM design which closely follows the design premise of maximising the space available for irradiation specimens in the IFMIF high flux zone and in addition allows keeping the temperature nearly constant in the rigs containing the specimen. Complementary analyses on nuclear, thermo-hydraulics and mechanical performance of the HFTM were performed to optimize the design. The present paper highlights the main design characteristics as well as recent progress achieved in this area. The contribution also includes (i) recommendations for the use of container, rig and capsule materials, and (ii) a description of the fabrication routes for the entire HFTM including brazing and filling procedures which are currently under development at the Forschungszentrum Karlsruhe.

  15. Thermal and hydrodynamic study of a whirling liquid hydrogen layer under high heat flux

    International Nuclear Information System (INIS)

    In order to achieve a cold neutrons source (λ ≥ 4.10-10 m) in a high flux reactor (∼ 1015 neutrons/cm2.s), a whirling liquid hydrogen layer (145 mm OD, effective thickness 15 mm, height about 180 mm) was formed, out-of-pile, in a cylindrical transparent glass vessel. The whirling motion was obtained by tangential injection of the liquid, near the wall. Thermal and hydrodynamical conditions of formation and laws of similarity of such a layer were studied. The characteristics of this whirling flow were observed as a function of mass flow rate (5 to 27 g/s; 4.3 to 23 l/mn), and of spillway width (18 and 25 mm). Six different nozzles were used : 1.0; 1.5; 1.9; 2.25; 2.65 and 3.0 mm ID. The total heat influx was found between 8.6 and 10.4 kW. The heat flux density was about 9.4 W/cm2 and the mean layer density around 80 per cent of that of the liquid hydrogen at 20.4 Kelvin. High speed movies were used to analyze the boiling regime. (author)

  16. Operational characteristics of the high flux plasma generator Magnum-PSI

    International Nuclear Information System (INIS)

    Highlights: •We have described the design and capabilities of the plasma experiment Magnum-PSI. •The plasma conditions are well suited for PSI studies in support of ITER. •Quasi steady state heat fluxes over 10 MW m−2 have been achieved. •Transient heat and particle loads can be generated to simulate ELM instabilities. •Lithium coating can be applied to the surfaces of samples under vacuum. -- Abstract: In Magnum-PSI (MAgnetized plasma Generator and NUMerical modeling for Plasma Surface Interactions), the high density, low temperature plasma of a wall stabilized dc cascaded arc is confined to a magnetized plasma beam by a quasi-steady state axial magnetic field up to 1.3 T. It aims at conditions that enable fundamental studies of plasma–surface interactions in the regime relevant for fusion reactors such as ITER: 1023–1025 m−2 s−1 hydrogen plasma flux densities at 1–5 eV. To study the effects of transient heat loads on a plasma-facing surface, a high power pulsed magnetized arc discharge has been developed. Additionally, the target surface can be transiently heated with a pulsed laser system during plasma exposure. In this contribution, the current status, capabilities and performance of Magnum-PSI are presented

  17. Status of research reactor fuel test in the High Flux Reactor (Petten)

    Energy Technology Data Exchange (ETDEWEB)

    Guidez, J.; Casalta, S. [European Commission, JRC, NL-1755 ZG Petten (Netherlands); Wijtsma, F.J.; Thijssen, P.J.M.; Hendriks, J.A.; Dassei, G. [NRG Petten (Netherlands); Vacelet, H. [Cerca Framatome, F-26104 Romans (France); Languille, A. [CEA Cadarache, F-13108 Saint Paul Lez Durance (France)

    2001-07-01

    Even if the research reactors are using very well known MTR-fuel, a need exists for research in this field mainly for the reasons of industrial qualification of fuel assemblies (built with qualified fuel), improvement or modifications on a qualified fuel ( e.g. increase of density), and qualification of a new fuels such as UMo. For these types of tests, the High Flux Reactor located in Petten (the Netherlands) has a lot of specific advantages: 1) a large core with various interesting positions ranging from high to low fluence rate; 2) a high number of operating days (>280 days/year) that gives - with the high flux available - a possibility to reach quickly high burnup; 3) a downward coolant flow that simplifies the device engineering; 4) all possibilities of non-destructive and destructive examinations in the hot-cells (visual inspection, swelling, {gamma}-scanning, macro- and light microscopy, SEM and EPMA examinations, tomography). Two types of tests can be performed at the plant: either a full-scale test or a test of plates in dedicated devices. A presentation is made of the irradiation test on four UMo plates, begun in March 2000 in the device UMUS. A status report is provided of the full-scale test to be done in the near future, especially the UMo tests to begin the next year. In conclusion it appears that the HFR, that had already given an excellent contribution to silicide fuel qualification in the 1980s, will also give a significant contribution to the current UMo qualification programs. (author)

  18. Brookhaven Lab and Argonne Lab scientists invent a plasma valve

    CERN Multimedia

    2003-01-01

    Scientists from Brookhaven National Laboratory and Argonne National Laboratory have received U.S. patent number 6,528,948 for a device that shuts off airflow into a vacuum about one million times faster than mechanical valves or shutters that are currently in use (1 page).

  19. From heavy ions to light sources at Brookhaven

    International Nuclear Information System (INIS)

    The Brookhaven National Laboratory, recovered from the debacle of the cancelled CBA proton-proton collider project, is now more than busy with an excellent physics programme at the 33 GeV Alternating Gradient Synchrotron and with solid projects for the years to come. (orig.).

  20. Brookhaven National Laboratory site environmental report for calendar year 1995

    Energy Technology Data Exchange (ETDEWEB)

    Naidu, J.R.; Paquette, D.E.; Schroeder, G.L. [eds.] [and others

    1996-12-01

    This report documents the results of the Environmental Monitoring Program at Brookhaven National Laboratory and summarizes information about environmental compliance for 1995. To evaluate the effect of Brookhaven National Laboratory`s operations on the local environment, measurements of direct radiation, and of a variety of radionuclides and chemical compounds in the ambient air, soil, sewage effluent, surface water, groundwater, fauna, and vegetation were made at the Brookhaven National Laboratory site and at adjacent sites. The report also evaluates the Laboratory`s compliance with all applicable guides, standards, and limits for radiological and nonradiological emissions and effluents to the environment. Areas of known contamination are subject to Remedial Investigation/Feasibility Studies under the Inter Agency Agreement established by the Department of Energy, Environmental Protection Agency and the New York Department of Environmental Conservation. Except for identified areas of soil and groundwater contamination, the environmental monitoring data has continued to demonstrate that compliance was achieved with the applicable environmental laws and regulations governing emission and discharge of materials to the environment. Also, the data show that the environmental impacts at Brookhaven National Laboratory are minimal and pose no threat to the public nor to the environment. This report meets the requirements of Department of Energy Orders 5484.1, Environmental Protection, Safety, and Health Protection Information reporting requirements and 5400.1, General Environmental Protection Programs.

  1. Vertical velocity variances and Reynold stresses at Brookhaven

    DEFF Research Database (Denmark)

    Busch, Niels E.; Brown, R.M.; Frizzola, J.A.

    1970-01-01

    Results of wind tunnel tests of the Brookhaven annular bivane are presented. The energy transfer functions describing the instrument response and the numerical filter employed in the data reduction process have been used to obtain corrected values of the normalized variance of the vertical wind...

  2. COMPUTATIONAL SCIENCE AT BROOKHAVEN NATIONAL LABORATORY: THREE SELECTED TOPICS.

    Energy Technology Data Exchange (ETDEWEB)

    DAVENPORT,J.W.DENG,Y.GLIMM,J.SAMULYAK,R.

    2003-09-15

    We present an overview of computational science at Brookhaven National Laboratory (BNL), with selections from three areas: fluids, nanoscience, and biology. The work at BNL in each of these areas is itself very broad, and we select a few topics for presentation within each of them.

  3. Brookhaven National Laboratory moves to the fast lane

    CERN Multimedia

    2006-01-01

    "The U.S. Department of Energy's energy sciences network (ESnet) continues to roll out its next-generation architecture on schedule with the March 14 completion of the Long Island Metropolitan Area Network, connecting Brookhaven National Laboratory (BNL) to the ESnet point of presente (PO) 60 miles away in New York City." (1 page)

  4. Fluxes of nitrates between snow surfaces and the atmosphere in the European high Arctic

    Directory of Open Access Journals (Sweden)

    H. J. Beine

    2003-01-01

    Full Text Available Measurements of atmospheric and snow mixing ratios of nitrates and nitrites and their fluxes above the snow surface were made during two intensive campaigns during spring time 2001 at Ny-Ålesund, Svalbard as part of the EU project  "`The NItrogen Cycle and Effects on the oxidation of atmospheric trace species at high latitudes' (NICE. At this coastal site close to the unseasonably unfrozen fjord, of the measured nitrogen species, only HNO3 showed a significant flux on to the snow surface; a mean deposition of -8.7 nmol h-1 m-2 was observed in late April / early May 2001. These fluxes may be due to the reaction of HNO3 with sea salt, and especially NaCl, or may be simply uptake of HNO3 by ice, which is alkaline because of the sea salt in our marine environment. During snowfall periods dry deposition of HNO3 may contribute up to 10% of the N budget in the snow; however, the main source for N is wet deposition in falling snow. The surface snow at Ny-Ålesund showed very complex stratigraphy; the NO3- mixing ratio in snow varied between 65 and 520 ng g-1, the total NO3- content of the snowpack was on the order of 2700 ng cm-2. In comparison the atmospheric boundary layer column showed a NO3- content of only 8 ng cm-2. The limited exchange, however, between the snow and the atmosphere was attributed to low mobility of NO3- in the observed snow. Contrary to other Arctic sites (i.e. Alert, Nunavut or Summit, Greenland deposition of sea salt and crustal aerosols in this marine environment made the surface snow alkaline; snow NO3- was associated with heavier cations and was not readily available for physical exchange or photochemical reactions.

  5. Development of the high sensitivity real-time neutron radiography for low-flux neutron sources

    International Nuclear Information System (INIS)

    The authors have developed a high-sensitivity real-time neutron radiography (NR) system by the use of the low power reactor of Kinki University. The system was constructed with a high efficiency neutron-photon converter, an image intensifier and a SIT TELEVISION camera. Some digital image processing techniques were applied for improving the quality of the real-time neutron images. By the use of this system, dynamic neutron imaging was performed successfully under the condition of a weak neutron field that was about two orders of magnitude lower than that of the standard NR system. The neutron flux, calculated from the fluctuation of the neutron response of the images, was nearly equal to the value measured by the foil activation method. From this fact, the efficiency for the neutron detection of the imaging system was estimated to be almost 100%. For the purpose of developing a system with higher sensitivity, consideration of neutron statistics would be important. (author)

  6. Establishing Specifications for Low Enriched Uranium Fuel Operations Conducted Outside the High Flux Isotope Reactor Site

    Energy Technology Data Exchange (ETDEWEB)

    Pinkston, Daniel [ORNL; Primm, Trent [ORNL; Renfro, David G [ORNL; Sease, John D [ORNL

    2010-10-01

    The National Nuclear Security Administration (NNSA) has funded staff at Oak Ridge National Laboratory (ORNL) to study the conversion of the High Flux Isotope Reactor (HFIR) from the current, high enriched uranium fuel to low enriched uranium fuel. The LEU fuel form is a metal alloy that has never been used in HFIR or any HFIR-like reactor. This report provides documentation of a process for the creation of a fuel specification that will meet all applicable regulations and guidelines to which UT-Battelle, LLC (UTB) the operating contractor for ORNL - must adhere. This process will allow UTB to purchase LEU fuel for HFIR and be assured of the quality of the fuel being procured.

  7. Diffusion regime of the magnetic flux penetration in high-temperature superconductors

    International Nuclear Information System (INIS)

    The magnetic flux penetration dynamics in superconductors of type II in the viscous flux regime is studied by analytically solving the nonlinear diffusion equation for the magnetic flux induction, using a power-law dependence of the differential resistivity on the magnetic field induction. An exact solution of nonlinear diffusion equation for the magnetic induction is obtained. (authors)

  8. Carbon dioxide in northern high latitude oceans: Anthropogenic increase and air-sea flux variability

    International Nuclear Information System (INIS)

    The aim of this thesis is to further our knowledge of carbon dioxide in the northern high latitude oceans (northern North Atlantic, Barents Sea, and Arctic Ocean) by studying the anthropogenic change in the oceanic CO2, the inter-annual variability of the air-sea CO2 flux, and the relationship between this variability and changes in other oceanic processes. An introductory chapter and four papers are presented. Descriptions of the seawater carbonate system parameters, air-sea exchange of CO2, and related processes are given in the introduction chapter. The anthropogenic increase in partial pressure of CO2 (pCO2) in the surface water of the Barents Sea is evaluated in paper I. The effect of alternations of the Barents Sea climate between cold and warm modes on the annual cycles of seawater fugacity and air-sea flux of CO2 is investigated in paper II. Oceanic uptake of atmospheric CO2 associated with the seasonal formation of sea ice in Storfjorden and the implication for the entire Arctic Ocean is studied in paper III. An assessment of the variations of the air-sea flux of CO2 in the northern North Atlantic for 20 winters (1981-2001) is carried out in paper IV. PCO2 in the surface water of the Barents Sea is shown to have increased parallel with the atmospheric pCO2 between 1967 and 2000-2001 (paper I). This was determined by comparing seawater pCO2 from 1967 with that from 2000-2001. The former was estimated from surface seawater temperature (SST) while the latter was computed from data of total dissolved inorganic carbon and alkalinity. A procedure which accounts for the natural variability was applied and the difference between seawater pC02 of 1967 and that of 2000-2001 is attributed to the uptake of excess CO2. In the Atlantic sector of the Barents Sea, the surface seawater fugacity of CO2 (fCO s''w) is shown to be lower than the atmospheric fCO2 throughout the year, implying that the area is an annual sink of atmospheric CO2 (paper II). Additionally, changes

  9. Carbon dioxide in northern high latitude oceans: Anthropogenic increase and air-sea flux variability

    Energy Technology Data Exchange (ETDEWEB)

    Omar, Abdirahman M.

    2003-07-01

    The aim of this thesis is to further our knowledge of carbon dioxide in the northern high latitude oceans (northern North Atlantic, Barents Sea, and Arctic Ocean) by studying the anthropogenic change in the oceanic CO2, the inter-annual variability of the air-sea CO2 flux, and the relationship between this variability and changes in other oceanic processes. An introductory chapter and four papers are presented. Descriptions of the seawater carbonate system parameters, air-sea exchange of CO2, and related processes are given in the introduction chapter. The anthropogenic increase in partial pressure of CO2 (pCO2) in the surface water of the Barents Sea is evaluated in paper I. The effect of alternations of the Barents Sea climate between cold and warm modes on the annual cycles of seawater fugacity and air-sea flux of CO2 is investigated in paper II. Oceanic uptake of atmospheric CO2 associated with the seasonal formation of sea ice in Storfjorden and the implication for the entire Arctic Ocean is studied in paper III. An assessment of the variations of the air-sea flux of CO2 in the northern North Atlantic for 20 winters (1981-2001) is carried out in paper IV. PCO2 in the surface water of the Barents Sea is shown to have increased parallel with the atmospheric pCO2 between 1967 and 2000-2001 (paper I). This was determined by comparing seawater pCO2 from 1967 with that from 2000-2001. The former was estimated from surface seawater temperature (SST) while the latter was computed from data of total dissolved inorganic carbon and alkalinity. A procedure which accounts for the natural variability was applied and the difference between seawater pC02 of 1967 and that of 2000-2001 is attributed to the uptake of excess CO2. In the Atlantic sector of the Barents Sea, the surface seawater fugacity of CO2 (fCO s''w) is shown to be lower than the atmospheric fCO2 throughout the year, implying that the area is an annual sink of atmospheric CO2 (paper II). Additionally

  10. High Time Resolution Measurements of Methane Fluxes From Enteric Fermentation in Cattle Rumen

    Science.gov (United States)

    Floerchinger, C. R.; Herndon, S.; Fortner, E.; Roscioli, J. R.; Kolb, C. E.; Knighton, W. B.; Molina, L. T.; Zavala, M.; Castelán, O.; Ku Vera, J.; Castillo, E.

    2013-12-01

    Methane accounts for roughly 20% of the global radiative climate forcing in the last two and a half centuries. Methane emissions arise from a number of anthropogenic and biogenic sources. In some areas enteric fermentation in livestock produces over 90% of agricultural methane. In the spring of 2013, as a part of the Short Lived Climate Forcer-Mexico field campaign, the Aerodyne Mobile Laboratory in partnership with the Molina Center for the Environment studied methane production associated with enteric fermentation in the rumen of cattle. A variety of different breeds and stocks being raised in two agricultural and veterinary research facilities located in different areas of Mexico were examined. Methane fluxes were quantified using two methods: 1) an atmospherically stable gaseous tracer release was collocated with small herds in a pasture, allowing tracer ratio flux measurements; 2) respiratory CO2 was measured in tandem with methane in the breath of individual animals allowing methane production to be related to metabolism. The use of an extensive suite of very high time response instruments allows for differentiation of individual methane producing rumination events and respiratory CO2 from possible background interferences. The results of these studies will be presented and compared to data from traditional chamber experiments.

  11. Constraints on the flux of Ultra-High Energy neutrinos from WSRT observations

    CERN Document Server

    Buitink, S; Bacelar, J; Braun, R; de Bruyn, A G; Falcke, H; Singh, K; Stappers, B; Strom, R G; Yahyaoui, R al

    2010-01-01

    Ultra-high energy (UHE) neutrinos and cosmic rays initiate particle cascades underneath the Moon's surface. These cascades have a negative charge excess and radiate Cherenkov radio emission in a process known as the Askaryan effect. The optimal frequency window for observation of these pulses with radio telescopes on the Earth is around 150 MHz. By observing the Moon with the Westerbork Synthesis Radio Telescope array we are able to set a new limit on the UHE neutrino flux. The PuMa II backend is used to monitor the Moon in 4 frequency bands between 113 and 175 MHz with a sampling frequency of 40 MHz. The narrowband radio interference is digitally filtered out and the dispersive effect of the Earth's ionosphere is compensated for. A trigger system is implemented to search for short pulses. By inserting simulated pulses in the raw data, the detection efficiency for pulses of various strength is calculated. With 47.6 hours of observation time, we are able to set a limit on the UHE neutrino flux. This new limit ...

  12. Reliable MOSFET operation using two-phase microfluidics in the presence of high heat flux transients

    International Nuclear Information System (INIS)

    Randomly generated heat flux transients affect the reliability of advanced integrated circuits and can induce severe nonlinearity in the device response, resulting in the degradation of a gate dielectric in metal oxide field effect transistors (MOSFETs). The effect of high heat flux transients on MOSFET operation and mitigation, using single-phase and two-phase on-chip microfluidics, is reported in this paper. A prototype comprising monolithically integrated MOSFETs, resistance temperature detector (RTD) arrays, simulated transient source (microheaters) and microfluidic networks was developed. The application of a 10 s transient (153 W cm−2) led to the degradation of subthreshold swing (S) from 120 to 240 mV/decade. However, in the presence of water flow, effective mitigation of S (up to 75%) is observed. The rate of mitigation is higher at lower flow rates because of the higher heat-transfer efficiency for two-phase flow. Thus, an appropriate selection of flow parameters can lead to optimized cooling. Additionally, we propose a strategy to localize the transient heat sources based on the temperature profiles generated using an on-chip, distributed RTD sensor array. The proposed methodology can be applied in practical integrated circuits for localization and characterization of heat sources leading to modifications in the circuit design or process integration steps.

  13. A dispersive nanoSQUID magnetometer for ultra-low noise, high bandwidth flux detection

    International Nuclear Information System (INIS)

    We describe a dispersive nanoSQUID (nanoscale superconducting quantum interference device) magnetometer comprised of two variable thickness aluminum weak-link Josephson junctions shunted in parallel with an on-chip capacitor. This arrangement forms a nonlinear oscillator with a tunable 4–8 GHz resonant frequency with a quality factor Q = 30 when coupled directly to a 50 Ω transmission line. In the presence of a near-resonant microwave carrier signal, a low frequency flux input generates sidebands that are readily detected using microwave reflectometry. If the carrier excitation is sufficiently strong, then the magnetometer also exhibits parametric gain, resulting in a minimum effective flux noise of 30 nΦ0 Hz−1/2 with 20 MHz of instantaneous bandwidth. If the magnetometer is followed with a near-quantum-noise-limited Josephson parametric amplifier, we can increase the bandwidth to 60 MHz without compromising sensitivity. This combination of high sensitivity and wide bandwidth with no on-chip dissipation makes this device ideal for local sensing of spin dynamics, both classical and quantum. (paper)

  14. Complete flux jump in bulk MgB2 sintered under high pressure

    International Nuclear Information System (INIS)

    Sintered MgB2 system was prepared under 3.5 GPa in the WC cubic anvil cell above 1100 deg. C for 1 h from the commercial MgB2. In this system, a few large flux jumps (FJ) were observed in the magnetization curve at 5 K on the field increasing process. Especially, the complete FJ occurred near 0 field. The number of large FJ decreased at higher temperature of 20 K. We estimated the flux density difference between the center and surface of the sample from the extended critical state model and magnetization data. The generation condition of FJ was discussed using Schwartz-Bean's theory and Wipf's theory. The FJ was suppressed at 20 K by the MgCu2 doping. We assumed that the present large FJ's were induced by the enlarged sample thickness by high pressure sintering. A few mol% of MgCu2 impurities reduced the thickness of MgB2 phase or enhanced the thermal conductivity of HP sample

  15. High flux testing reactor Petten. Replacement of the reactor vessel and connected components. Overall report

    International Nuclear Information System (INIS)

    The project of replacing the HFR originated in 1974 when results of several research programmes confirmed severe neutron embrittlement of aluminium alloys suggesting a limited life of the existing facility. This report contains the detailed chronology of events concerning preparation and execution of the replacement. After a 14 months' outage the reactor resumed routine operation on 14th February, 1985. At the end of several years of planning and preparation the reconstruction proceded in the following steps: unloading of the old core, decay of short-lived radioactivity in December 1983, removal of the old tank and of its peripheral equipment in January-February 1984, segmentation and waste disposal of the removed components in March-April, decontamination of the pools, bottom penetration overhauling in May-June, installation of the new tank and other new components in July-September, testing and commissioning, including minor modifications in October-December, and, trials runs and start-up preparation in January-February 1985. The new HFR Petten features increased and improved experimental facilities. Among others the obsolete thermal columns was replaced by two high flux beam tubes. Moreover the new plant has been designed for future increases of reactor power and neutron fluxes. For the next three to four years the reactor has to cope with a large irradiation programme, claiming its capacity to nearly 100%

  16. Evaluation of HFIR [High Flux Isotope Reactor] pressure-vessel integrity considering radiation embrittlement

    International Nuclear Information System (INIS)

    The High Flux Isotope Reactor (HFIR) pressure vessel has been in service for 20 years, and during this time, radiation damage was monitored with a vessel-material surveillance program. In mid-November 1986, data from this program indicated that the radiation-induced reduction in fracture toughness was greater than expected. As a result, a reevaluation of vessel integrity was undertaken. Updated methods of fracture-mechanics analysis were applied, and an accelerated irradiations program was conducted using the Oak Ridge Research Reactor. Results of these efforts indicate that (1) the vessel life can be extended 10 years if the reactor power level is reduced 15% and if the vessel is subjected to a hydrostatic proof test each year; (2) during the 10-year life extension, significant radiation damage will be limited to a rather small area around the beam tubes; and (3) the greater-than-expected damage rate is the result of the very low neutron flux in the HFIR vessel relative to that in samples of material irradiated in materials-testing reactors (a factor of ∼104 less), that is, a rate effect

  17. Characterization of the irradiation parameters in the IFMIF high flux test region

    Science.gov (United States)

    Daum, E.; Wilson, P. P. H.; Fischer, U.; Ehrlich, K.

    1998-10-01

    The purpose of the international fusion materials irradiation facility (IFMIF) is to provide typical D-T fusion irradiation conditions for future material testing and material development. In order to demonstrate the suitability of IFMIF for irradiation experiments a comprehensive characterization of the neutronics of the high flux test region (HFTR) has been carried out. For Fe, the neutron flux density was found to range between 4 × 10 14 and 10 15 n/s cm 2 which corresponds to 20-55 DPA/FPY in a maximum volume of 550 ± 180 cm 3. Gas production rates were calculated and a H/DPA ratio of 35-50 appm/DPA and a He/DPA ratio of 10-12 appm/DPA were found, which are very similar to those of a DEMO D-T fusion reactor. Additionally, an analysis of the primary knock-on spectra has been performed and a displacement damage characteristic in IFMIF almost ideal to the first wall of DEMO was found. IFMIF therefore provides an adequate environment for the simulation of D-T fusion reactor irradiation conditions.

  18. Characterization of the irradiation parameters in the IFMIF high flux test region

    International Nuclear Information System (INIS)

    The purpose of the international fusion materials irradiation facility (IFMIF) is to provide typical D-T fusion irradiation conditions for future material testing and material development. In order to demonstrate the suitability of IFMIF for irradiation experiments a comprehensive characterization of the neutronics of the high flux test region (HFTR) has been carried out. For Fe, the neutron flux density was found to range between 4 x 1014 and 1015 n/s cm2 which corresponds to 20-55 DPA/FPY in a maximum volume of 550 ± 180 cm3. Gas production rates were calculated and a H/DPA ratio of 35-50 appm/DPA and a He/DPA ratio of 10-12 appm/DPA were found, which are very similar to those of a DEMO D-T fusion reactor. Additionally, an analysis of the primary knock-on spectra has been performed and a displacement damage characteristic in IFMIF almost ideal to the first wall of DEMO was found. IFMIF therefore provides an adequate environment for the simulation of D-T fusion reactor irradiation conditions. (orig.)

  19. Molecular Imprinted Membrane with High Flux by Surface Photo-grafting Copolymerization

    Institute of Scientific and Technical Information of China (English)

    李爽; 张凤宝; 张国亮; 王燕

    2005-01-01

    Molecular imprinted polymer membranes (MIM) combine the merits of molecular imprint and membrane technology. In this work, a very thin of imprinted polymer that can specifically and selectively absorb the basic template (adenine) was grafted on the surface of polyvinylidene fluoride membrane by photo-grafting copolymerization. Because the molecular imprinted polymer is grafted on the surface of the matrix membrane without blocking the membrane pores, the resultant MIMs have high flux as microfiltration membrane (0.26 mol·m-2·h-1 of template and flux for distilled water was 3.6 ml·mim-1·cm-2 at 0.8 MPa). Moreover, the MIMs can absorb/desorb template molecules rapidly. Usually, it only takes several minutes for MIMs to absorb more than 75% of the template (adenine) in aqueous solution. And the influences of the type and amount of the functional monomers, the amount of the cross-linker on the absorption capability are discussed to determine the optimal preparation conditions。

  20. Constraints on the flux of Ultra-High Energy neutrinos from WSRT observations

    Energy Technology Data Exchange (ETDEWEB)

    Scholten, O; Bacelar, J; Braun, R; de Bruyn, A G; Falcke, H; Singh, K; Stappers, B; Strom, R G; al Yahyaoui, R

    2010-04-02

    Context. Ultra-high energy (UHE) neutrinos and cosmic rays initiate particle cascades underneath the Moon's surface. These cascades have a negative charge excess and radiate Cherenkov radio emission in a process known as the Askaryan effect. The optimal frequency window for observation of these pulses with radio telescopes on the Earth is around 150 MHz. Aims. By observing the Moon with the Westerbork Synthesis Radio Telescope array we are able to set a new limit on the UHEneutrino flux. Methods. The PuMa II backend is used to monitor the Moon in 4 frequency bands between 113 and 175 MHz with a sampling frequency of 40 MHz. The narrow band radio interference is digitally filtered out and the dispersive effect of the Earth?s ionosphere is compensated for. A trigger system is implemented to search for short pulses. By inserting simulated pulses in the raw data, the detection efficiency for pulses of various strength is calculated. Results. With 47.6 hours of observation time, we are able to set a limit on the UHE neutrino flux. This new limit is an order of magnitude lower than existing limits. In the near future, the digital radio array LOFAR will be used to achieve an even lower limit.

  1. Modeling the reduction of gross lithium erosion observed under high-flux deuterium bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Abrams, T., E-mail: tabrams@pppl.gov [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Jaworski, M.A.; Kaita, R.; Nichols, J.H.; Stotler, D.P. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); De Temmerman, G.; Berg, M.A. van den; Meiden, H.J. van der; Morgan, T.W. [FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research, Trilateral Euregio Cluster, Associate EURATOM-FOM, BL-3430 BE Nieuwegein (Netherlands)

    2015-08-15

    Both thin (<1 μm) and thick (∼500 μm) lithium films under high-flux deuterium and neon plasma bombardment were studied in the linear plasma device Magnum-PSI at ion fluxes >10{sup 24} m{sup −2} s{sup −1} and surface temperatures <700 °C. During Ne plasma exposures, Li erosion rates inferred from measurements of Li–I radiation exceed Langmuir Law evaporation, but no previous results exist to benchmark the binary collision approximation (BCA) and thermal sputtering measurements. Measured Li erosion rates during D plasma bombardment were compared to the adatom-evaporation model of thermal sputtering with an additional reduction term to account for the relative D/Li composition of the Li film. This model captures the qualitative evolution of the Li erosion yield but still overestimates the measured erosion by a factor of 5–10. This suggests that additional refinements to the mixed-material model are needed.

  2. Physics design for the Brookhaven Medical Research Reactor epithermal neutron source

    International Nuclear Information System (INIS)

    A collaborative effort by researchers at the Idaho National Engineering Laboratory and the Brookhaven National Laboratory has resulted in the design and implementation of an epithermal-neutron source at the Brookhaven Medical Research Reactor (BMRR). Large aluminum containers, filled with aluminum oxide tiles and aluminum spacers, were tailored to pre-existing compartments on the animal side of the reactor facility. A layer of cadmium was used to minimize the thermal-neutron component. Additional bismuth was added to the pre-existing bismuth shield to minimize the gamma component of the beam. Lead was also added to reduce gamma streaming around the bismuth. The physics design methods are outlined in this paper. Information available to date shows close agreement between calculated and measured beam parameters. The neutron spectrum is predominantly in the intermediate energy range (0.5 eV - 10 keV). The peak flux intensity is 6.4E + 12 n/(m2.s.MW) at the center of the beam on the outer surface of the final gamma shield. The corresponding neutron current is 3.8E + 12 n/(m2.s.MW). Presently, the core operates at a maximum of 3 MW. The fast-neutron KERMA is 3.6E-15 cGy/(n/m2) and the gamma KERMA is 5.0E-16 cGY/(n/m2) for the unperturbed beam. The neutron intensity falls off rapidly with distance from the outer shield and the thermal flux realized in phantom or tissue is strongly dependent on the beam-delimiter and target geometry

  3. High-frequency analysis of the complex linkage between soil CO(2) fluxes, photosynthesis and environmental variables.

    Science.gov (United States)

    Martin, Jonathan G; Phillips, Claire L; Schmidt, Andres; Irvine, James; Law, Beverly E

    2012-01-01

    High-frequency soil CO(2) flux data are valuable for providing new insights into the processes of soil CO(2) production. A record of hourly soil CO(2) fluxes from a semi-arid ponderosa pine stand was spatially and temporally deconstructed in attempts to determine if variation could be explained by logical drivers using (i) CO(2) production depths, (ii) relationships and lags between fluxes and soil temperatures, or (iii) the role of canopy assimilation in soil CO(2) flux variation. Relationships between temperature and soil fluxes were difficult to establish at the hourly scale because diel cycles of soil fluxes varied seasonally, with the peak of flux rates occurring later in the day as soil water content decreased. Using a simple heat transport/gas diffusion model to estimate the time and depth of CO(2) flux production, we determined that the variation in diel soil CO(2) flux patterns could not be explained by changes in diffusion rates or production from deeper soil profiles. We tested for the effect of gross ecosystem productivity (GEP) by minimizing soil flux covariance with temperature and moisture using only data from discrete bins of environmental conditions (±1 °C soil temperature at multiple depths, precipitation-free periods and stable soil moisture). Gross ecosystem productivity was identified as a possible driver of variability at the hourly scale during the growing season, with multiple lags between ~5, 15 and 23 days. Additionally, the chamber-specific lags between GEP and soil CO(2) fluxes appeared to relate to combined path length for carbon flow (top of tree to chamber center). In this sparse and heterogeneous forested system, the potential link between CO(2) assimilation and soil CO(2) flux may be quite variable both temporally and spatially. For model applications, it is important to note that soil CO(2) fluxes are influenced by many biophysical factors, which may confound or obscure relationships with logical environmental drivers and act at

  4. Flux-line entanglement as the mechanism of melting transition in high-temperature superconductors in a magnetic field

    OpenAIRE

    Nonomura, Yoshihiko; Hu, Xiao; TACHIKI, Masashi

    1998-01-01

    The mechanism of the flux-line-lattice (FLL) melting in anisotropic high-T_c superconductors in ${\\bf B}\\parallel {\\bf \\hat{c}}$ is clarified by Monte Carlo simulations of the 3D frustrated XY model. The percentage of entangled flux lines abruptly changes at the melting temperature T_m, while no sharp change can be found in the number and size distribution of vortex loops around T_m. Therefore, the origin of this melting transition is the entanglement of flux lines. Scaling behaviors of physi...

  5. Seasonal and diurnal variability of the meteor flux at high latitudes observed using PFISR

    Science.gov (United States)

    Sparks, J. J.; Janches, D.; Nicolls, M. J.; Heinselman, C. J.

    2009-05-01

    We report in this and a companion paper [Fentzke, J.T., Janches, D., Sparks, J.J., 2008. Latitudinal and seasonal variability of the micrometeor input function: A study using model predictions and observations from Arecibo and PFISR. Journal of Atmospheric and Solar-Terrestrial Physics, this issue, doi:10.1016/j.jastp.2008.07.015] a complete seasonal study of the micrometeor input function (MIF) at high latitudes using meteor head-echo radar observations performed with the Poker Flat Incoherent Scatter Radar (PFISR). This flux is responsible for a number of atmospheric phenomena; for example, it could be the source of meteoric smoke that is thought to act as condensation nuclei in the formation of ice particles in the polar mesosphere. The observations presented here were performed for full 24-h periods near the summer and winter solstices and spring and autumn equinoxes, times at which the seasonal variability of the MIF is predicted to be large at high latitudes [Janches, D., Heinselman, C.J., Chau, J.L., Chandran, A., Woodman, R., 2006. Modeling of the micrometeor input function in the upper atmosphere observed by High Power and Large Aperture Radars, JGR, 11, A07317, doi:10.1029/2006JA011628]. Precise altitude and radar instantaneous line-of-sight (radial) Doppler velocity information are obtained for each of the hundreds of events detected every day. We show that meteor rates, altitude, and radial velocity distributions have a large seasonal dependence. This seasonal variability can be explained by a change in the relative location of the meteoroid sources with respect to the observer. Our results show that the meteor flux into the upper atmosphere is strongly anisotropic and its characteristics must be accounted for when including this flux into models attempting to explain related aeronomical phenomena. In addition, the measured acceleration and received signal strength distribution do not seem to depend on season; which may suggest that these observed

  6. IFMIF high flux test module - recent progress in design and manufacturing

    International Nuclear Information System (INIS)

    The International Fusion Material Irradiation Facility (IFMIF) is an accelerator driven neutron source for irradiation tests of candidate fusion reactor materials. Two 40 MeV deuterium beams with 125 mA each strike a liquid lithium jet target, producing a high intensity neutron flux up to 55 MeV, which penetrates the adjacent test modules. Within the High Flux Test Module (HFTM) a testing volume of 0.5 litres filled by qualified small scale specimens will be irradiated at displacement rates of 20-50 dpa/fpy in structural materials. The HFTM will also provide helium and hydrogen production to dpa ratios that reflect within the uncertainties the values expected in a DEMO fusion reactor The Forschungszentrum Karlsruhe (FZK) has developed a HFTM design which closely follows the design premise of maximising the space available for irradiation specimens in the IFMIF high flux zone and in addition allows keeping the temperature nearly constant in the rigs containing the specimen. Within the entire specimen stack the temperature deviation will be below about 15 K. The main design principles applied are (i) filling the gaps between the specimens with liquid metal, (ii) winding three separately controlled heater sections on the inner capsules and (iii) dividing the test rigs in a hot inner and a cold outer zone, which a separated by a gap filled with stagnant helium that serves as a thermal insulator. Channels between the outer covers (the cold parts) are cooled by helium gas at moderate pressure (3 bars at inlet) and temperature (50 C). 12 identical rigs holding the specimen capsules which are heated by segmented helically wound electrical heaters ensure a flexible loading scheme during IFMIF operation. Complementary analyses on nuclear, thermo-hydraulics and mechanical performance of the HFTM were performed to optimize the design. The present paper highlights the main design characteristics as well as recent progress achieved in this area. This includes the stiffening of

  7. Microscopic Deformation of Tungsten Surfaces by High Energy and High Flux Helium/Hydrogen Particle Bombardment with Short Pulses

    Science.gov (United States)

    Tokitani, Masayuki; Yoshida, Naoaki; Tokunaga, Kazutoshi; Sakakita, Hajime; Kiyama, Satoru; Koguchi, Haruhisa; Hirano, Yoichi; Masuzaki, Suguru

    The neutral beam injection facility in the National Institute of Advanced Industrial Science and Technology was used to irradiate a polycrystalline tungsten specimen with high energy and high flux helium and hydrogen particles. The incidence energy and flux of the beam shot were 25 keV and 8.8 × 1022 particles/m2 s, respectively. The duration of each shot was approximately 30 ms, with 6 min intervals between each shot. Surface temperatures over 1800 K were attained. In the two cases of helium irradiation, total fluence of either 1.5 × 1022 He/m2 or 4.0 × 1022 He/m2 was selected. In the former case, large sized blisters with diameter of 500 nm were densely observed. While, the latter case, the blisters were disappeared and fine nanobranch structures appeared instead. Cross-sectional observations using a transmission electron microscope (TEM) with the focused ion beam (FIB) technique were performed. According to the TEM image, after irradiation with a beam shot of total fluence 4.0 × 1022 He/m2 , there were very dense fine helium bubbles in the tungsten of sizes 1-50 nm. As the helium bubbles grew the density of the tungsten matrix drastically decreased as a result of void swelling. These effects were not seen in hydrogen irradiation case.

  8. High resolution powder neutron diffraction at a low-flux reactor

    International Nuclear Information System (INIS)

    Complete text of publication follows. The high resolution powder neutron diffractometer, PUS, was installed at the 2 MW JEEP II reactor at Institute for Energy Technology, Kjeller in 1997. Flexibility and optimisation of the relationship between intensity (signal/noise ratio) and resolution were keywords for the design of the instrument [1]. Wavelengths in the range 0.7 - 2.6 A are available from the focussing composite Ge monochromator. Different Soller slit collimators in the incident neutron beam allow either a high resolution or a high intensity mode. The detector system consists of two units position units, each covering 20 deg in 2Θ, and a complete 120 degrees powder pattern are collected from measurements with the detector-units in three different positions. The presentation focus is on some selected examples, like crystal and magnetic structures of metal hydrides, high TC-superconductors and perovskite related oxides, to show the potential of high resolution powder neutron diffraction at a low-flux reactor, like the JEEP II reactor at Kjeller. (author) [1] B.C. Hauback, H. Fjellvag, O. Steinsvoll, K. Johansson, O.T. Buset and J. Jorgensen, to be submitted (1999)

  9. A combined maximum-likelihood analysis of the high-energy astrophysical neutrino flux measured with IceCube

    CERN Document Server

    Aartsen, M G; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Ahrens, M; Altmann, D; Anderson, T; Archinger, M; Arguelles, C; Arlen, T C; Auffenberg, J; Bai, X; Barwick, S W; Baum, V; Bay, R; Beatty, J J; Tjus, J Becker; Becker, K -H; Beiser, E; BenZvi, S; Berghaus, P; Berley, D; Bernardini, E; Bernhard, A; Besson, D Z; Binder, G; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohm, C; Börner, M; Bos, F; Bose, D; Böser, S; Botner, O; Braun, J; Brayeur, L; Bretz, H -P; Brown, A M; Buzinsky, N; Casey, J; Casier, M; Cheung, E; Chirkin, D; Christov, A; Christy, B; Clark, K; Classen, L; Coenders, S; Cowen, D F; Silva, A H Cruz; Daughhetee, J; Davis, J C; Day, M; de André, J P A M; De Clercq, C; Dembinski, H; De Ridder, S; Desiati, P; de Vries, K D; de Wasseige, G; de With, M; DeYoung, T; Díaz-Vélez, J C; Dumm, J P; Dunkman, M; Eagan, R; Eberhardt, B; Ehrhardt, T; Eichmann, B; Euler, S; Evenson, P A; Fadiran, O; Fahey, S; Fazely, A R; Fedynitch, A; Feintzeig, J; Felde, J; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Fuchs, T; Gaisser, T K; Gaior, R; Gallagher, J; Gerhardt, L; Ghorbani, K; Gier, D; Gladstone, L; Glagla, M; Glüsenkamp, T; Goldschmidt, A; Golup, G; Gonzalez, J G; Goodman, J A; Góra, D; Grant, D; Gretskov, P; Groh, J C; Groß, A; Ha, C; Haack, C; Ismail, A Haj; Hallgren, A; Halzen, F; Hansmann, B; Hanson, K; Hebecker, D; Heereman, D; Helbing, K; Hellauer, R; Hellwig, D; Hickford, S; Hignight, J; Hill, G C; Hoffman, K D; Hoffmann, R; Holzapfel, K; Homeier, A; Hoshina, K; Huang, F; Huber, M; Huelsnitz, W; Hulth, P O; Hultqvist, K; In, S; Ishihara, A; Jacobi, E; Japaridze, G S; Jero, K; Jurkovic, M; Kaminsky, B; Kappes, A; Karg, T; Karle, A; Kauer, M; Keivani, A; Kelley, J L; Kemp, J; Kheirandish, A; Kiryluk, J; Kläs, J; Klein, S R; Kohnen, G; Kolanoski, H; Konietz, R; Koob, A; Köpke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krings, K; Kroll, G; Kroll, M; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Lanfranchi, J L; Larson, M J; Lesiak-Bzdak, M; Leuermann, M; Leuner, J; Lünemann, J; Madsen, J; Maggi, G; Mahn, K B M; Maruyama, R; Mase, K; Matis, H S; Maunu, R; McNally, F; Meagher, K; Medici, M; Meli, A; Menne, T; Merino, G; Meures, T; Miarecki, S; Middell, E; Middlemas, E; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Niederhausen, H; Nowicki, S C; Nygren, D R; Obertacke, A; Olivas, A; Omairat, A; O'Murchadha, A; Palczewski, T; Paul, L; Pepper, J A; Heros, C Pérez de los; Pfendner, C; Pieloth, D; Pinat, E; Posselt, J; Price, P B; Przybylski, G T; Pütz, J; Quinnan, M; Rädel, L; Rameez, M; Rawlins, K; Redl, P; Reimann, R; Relich, M; Resconi, E; Rhode, W; Richman, M; Richter, S; Riedel, B; Robertson, S; Rongen, M; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Sabbatini, L; Sander, H -G; Sandrock, A; Sandroos, J; Sarkar, S; Schatto, K; Scheriau, F; Schimp, M; Schmidt, T; Schmitz, M; Schoenen, S; Schöneberg, S; Schönwald, A; Schukraft, A; Schulte, L; Seckel, D; Seunarine, S; Shanidze, R; Smith, M W E; Soldin, D; Spiczak, G M; Spiering, C; Stahlberg, M; Stamatikos, M; Stanev, T; Stanisha, N A; Stasik, A; Stezelberger, T; Stokstad, R G; Stößl, A; Strahler, E A; Ström, R; Strotjohann, N L; Sullivan, G W; Sutherland, M; Taavola, H; Taboada, I; Ter-Antonyan, S; Terliuk, A; Tešić, G; Tilav, S; Toale, P A; Tobin, M N; Tosi, D; Tselengidou, M; Unger, E; Usner, M; Vallecorsa, S; Vandenbroucke, J; van Eijndhoven, N; Vanheule, S; van Santen, J; Veenkamp, J; Vehring, M; Voge, M; Vraeghe, M; Walck, C; Wallace, A; Wallraff, M; Wandkowsky, N; Weaver, C; Wendt, C; Westerhoff, S; Whelan, B J; Whitehorn, N; Wichary, C; Wiebe, K; Wiebusch, C H; Wille, L; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, D L; Xu, X W; Xu, Y; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Zoll, M

    2015-01-01

    Evidence for an extraterrestrial flux of high-energy neutrinos has now been found in multiple searches with the IceCube detector. The first solid evidence was provided by a search for neutrino events with deposited energies $\\gtrsim30$~TeV and interaction vertices inside the instrumented volume. Recent analyses suggest that the extraterrestrial flux extends to lower energies and is also visible with throughgoing, $\

  10. Implications of ultra-high energy neutrino flux constraints for Lorentz-invariance violating cosmogenic neutrinos

    CERN Document Server

    Gorham, P W; Allison, P; Beatty, J J; Belov, K; Besson, D Z; Binns, W R; Chen, P; Clem, J M; Hoover, S; Israel, M H; Nam, J; Saltzberg, D; Varner, G S; Vieregg, A G

    2012-01-01

    We consider the implications of Lorentz-invariance violation (LIV) on cosmogenic neutrino observations, with particular focus on the constraints imposed on several well-developed models for ultra-high energy cosmogenic neutrino production by recent results from the Antarctic Impulsive Transient Antenna (ANITA) long-duration balloon payload, and Radio Ice Cherenkov Experiment (RICE) at the South Pole. Under a scenario proposed originally by Coleman and Glashow, each lepton family may attain maximum velocities that can exceed the speed of light, leading to energy-loss through several interaction channels during propagation. We show that future observations of cosmogenic neutrinos will provide by far the most stringent limit on LIV in the neutrino sector. We derive the implied level of LIV required to suppress observation of predicted fluxes from several mainstream cosmogenic neutrino models, and specifically those recently constrained by the ANITA and RICE experiments. We simulate via detailed Monte Carlo code ...

  11. New Limits on the Ultra-high Energy Cosmic Neutrino Flux from the ANITA Experiment

    CERN Document Server

    Gorham, P; Beatty, J; Besson, D; Binns, W; Chen, C; Chen, P; Clem, J; Connolly, A; Dowkontt, P; DuVernois, M; Field, R; Goldstein, D; Goodhue, A; Hast, C; Hebert, C; Hoover, S; Israel, M; Kowalski, J; Learned, J; Liewer, K; Link, J; Lusczek, E; Matsuno, S; Mercurio, B; Miki, C; Miocinovic, P; Nam, J; Naudet, C; Nichol, R; Palladino, K; Reil, K; Romero-Wolf, A; Rosen, M; Ruckman, L; Saltzberg, D; Seckel, D; Varner, G; Walz, D; Wang, Y; Wu, F

    2008-01-01

    We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA-1) 2006-2007 Long Duration Balloon flight, which searched for evidence of a diffuse flux of cosmic neutrinos above energies of 3 EeV. ANITA-1 flew for 35 days looking for radio impulses due to the Askaryan effect in neutrino-induced electromagnetic showers within the Antarctic ice sheets. We report here on our initial analysis, which was performed as a blind search of the data. No neutrino candidates are seen, with no detected physics background. We set model-independent limits based on this result. Upper limits derived from our analysis rule out the highest cosmogenic neutrino models. In a background horizontal-polarization channel, we also detect six events consistent with radio impulses from ultra-high energy extensive air showers.

  12. Surface hardening induced by high flux plasma in tungsten revealed by nano-indentation

    Science.gov (United States)

    Terentyev, D.; Bakaeva, A.; Pardoen, T.; Favache, A.; Zhurkin, E. E.

    2016-08-01

    Surface hardness of tungsten after high flux deuterium plasma exposure has been characterized by nanoindentation. The effect of plasma exposure was rationalized on the basis of available theoretical models. Resistance to plastic penetration is enhanced within the 100 nm sub-surface region, attributed to the pinning of geometrically necessary dislocations on nanometric deuterium cavities - signature of plasma-induced defects and deuterium retention. Sub-surface extension of thereby registered plasma-induced damage is in excellent agreement with the results of alternative measurements. The study demonstrates suitability of nano-indentation to probe the impact of deposition of plasma-induced defects in tungsten on near surface plasticity under ITER-relevant plasma exposure conditions.

  13. Searches for high frequency variations in the 8-B neutrino flux at the Sudbury neutrino observatory

    Energy Technology Data Exchange (ETDEWEB)

    Rielage, Keith [Los Alamos National Laboratory; Seibert, Stanley R [Los Alamos National Laboratory; Hime, Andrew [Los Alamos National Laboratory; Elliott, Steven R [Los Alamos National Laboratory; Stonehill, L C [Los Alamos National Laboratory; Wouters, J M [Los Alamos National Laboratory; Aharmim, B [LAURENTIAN UNIV; Ahmed, S N [QUEEN' S UNIV; Anthony, A E [UNIV OF TEXAS; Barros, N [PORTUGAL; Beier, E W [UNIV OF PA; Bellerive, A [CARLETON UNIV; Belttran, B [UNIV OF ALBERTA; Bergevin, M [LBNL; Biller, S D [UNIV OF OXFORD; Boudjemline, K [CARLETON UNIV; Burritt, T H [UNIV OF WASHINGTON; Cai, B [QUEEN' S UNIV; Chan, Y D [LBNL; Chauhan, D [LAURENTIAN UNIV; Chen, M [QUEEN' S UNIV; Cleveland, B T [UNIV OF OXFORD; Cox - Mobrand, G A [UNIV OF WASHINGTON; Dai, X [QUEEN' S UNIV; Deng, H [UNIV OF PA; Detwiler, J [LBNL; Dimarco, M [QUEEN' S UNIV; Doe, P J [UNIV OF WASHINGTON; Drouin, P - L [CARLTON UNIV; Duba, C A [UNIV OF WASHINGTON; Duncan, F A [SNOLAB, SUDBURY; Dunford, M [UNIV OF PA; Earle, E D [QUEEN' S UNIV; Evans, H C [QUEEN' S UNIV; Ewan, G T [QUEEN' S UNIV; Farine, J [LAURENTTIAN UNIV; Fergani, H [UNIV OF OXFORD; Fleurot, F [LAURENTIAN UNIV; Ford, R J [SNOLAB, SUDBURY; Formaggilo, J A [MASSACHUSETTS INST. OF TECH.; Gagnon, N [UNIV OF WASHINGTON; Goon, J Tm [LOUISIANA STATE UNIV; Guillian, E [QUEEN' S UNIV; Habib, S [UNIV OF ALBERTA; Hahn, R L [BNL; Hallin, A L [UNIV OF ALBERTA; Hallman, E D [LAURENTIAN UNIV; Harvey, P J [QUEEN' S UNIV; Hazama, R [UNIV OF WASHINGTON; Heintzelman, W J [UNIV OF PA; Heise, J [SNOLAB, SUDBURY; Helmer, R L [TRIUMF; Howard, C [UNIV OF ALBERTA; Howe, M A [UNIV OF WASHINGTON; Huang, M [UNIV OF TEXAS; Jamieson, B [UNIV OF BRITISH COLUMBIA; Jelley, N A [UNIV OF OXFORD; Keeter, K J [SNOLAB, SUDBURY; Klein, J R [UNIV OF TEXAS; Kos, M [QUEEN' S UNIV; Kraus, C [QUEEN' S UNIV; Krauss, C B [UNIV OF ALBERTA; Kutter, T [LOUISIANA STATE UNIV; Kyba, C C M [UNIV OF PA; Law, J [UNIV OF GUELPH; Lawson, I T [SNOLAB, SUDBURY; Lesko, K T [LBNL; Leslie, J R [QUEEN' S UNIV; Loach, J C [UNIV OF OXFORD; Maclellan, R [QUEEN' S UNIV; Majerus, S [UNIV OF OXFORD; Mak, H B [QUEEN' S UNIV; Maneira, J [PORTUGAL; Martin, R [QUEEN' S UNIV; Mccauley, N [UNIV OF PA; Mc Donald, A B [QUEEN' S UNIV; Mcgee, S [UNIV OF WASHINGTON; Miffin, C [CARLETON UNIV; Miller, M L [MASSACHUSETTS INST. OF TECH.; Monreal, B [MASSACHUSETTS INST. OF TECH.; Monroe, J [MASSACHUSETTS INST. OF TECH; Morissette, B [SNOLAB, SUDBURY; Nickel, B G [UNIV OF GUELPH; Noble, A J [QUEEN' S UNIV; O' Keeffe, H M [UNIV OF OXFORD; Oblath, N S [UNIV OF WASHINGTON; Orebi Gann, G D [UNIV OF OXFORD; Oser, S M [UNIV OF BRITISH COLUMBIA; Ott, R A [MASSACHUSETTS INST. OF TECH.; Peeters, S J M [UNIV OF OXFORD; Poon, A W P [LBNL; Prior, G [LBNL; Reitzner, S D [UNIV OF GUELPH; Robertson, B C [QUEEN' S UNIV; Robertson, R G H [UNIV OF WASHINGTON; Rollin, E [CARLETON UNIV; Schwendener, M H [LAURENTIAN UNIV; Secrest, J A [UNIV OF PA; Seibert, S R [UNIV OF TEXAS; Simard, O [CARLETON UNIV; Sinclair, D [CARLETON UNIV; Sinclair, L [CARLETON UNIV; Skensved, P [QUEEN' S UNIV; Sonley, T J [MASSACHUSETTS INST. OF TECH.; Tesic, G [CARLETON UNIV; Tolich, N [UNIV OF WASHINGTON; Tsui, T [UNIV OF BRITISH COLUMBIA; Tunnell, C D [UNIV OF TEXAS; Van Berg, R [UNIV OF PA; Van Devender, B A [UNIV OF WASHINGTON; Virtue, C J [LAURENTIAN UNIV; Wall, B L [UNIV OF WASHINGTON; Waller, D [CARLETON UNIV; Wan Chan Tseung, H [UNIV OF OXFORD; West, N [UNIV OF OXFORD; Wilkerson, J F [UNIV OF WASHINGTON; Wilson, J R [UNIV OF OXFORD; Wright, A [QUEEN' S UNIV; Yeh, M [BNL; Zhang, F [CARLETON UNIV; Zuber, K [UNIV OF OXFORD

    2009-01-01

    We have peformed three searches for high-frequency signals in the solar neutrino flux measured by the Sudbury Neutrino Observatory (SNO), motivated by the possibility that solar g-mode oscillations could affect the production or propagation of solar {sup 8}B neutrinos. The first search looked for any significant peak in the frequency range l/day to 144/day, with a sensitivity to sinusoidal signals with amplitudes of 12% or greater. The second search focused on regions in which g-mode signals have been claimed by experiments aboard the SoHO satellite, and was sensitive to signals with amplitudes of 10% or greater. The third search looked for extra power across the entire frequency band. No statistically significant signal was detected in any of the three searches.

  14. High flux cold Rubidium atomic beam for strongly coupled Cavity QED

    CERN Document Server

    Roy, Basudev

    2012-01-01

    This paper presents a setup capable of producing a high-flux continuous beam of cold rubidium atoms for cavity QED experiments in the regime of strong coupling. A 2 $D^+$ MOT, loaded by rubidium getters in a dry film coated vapor cell, fed a secondary moving-molasses MOT (MM-MOT) at a rate of 1.5 x $10^{10}$ atoms/sec. The MM-MOT provided a continuous beam with tunable velocity. This beam was then directed through the waist of a 280 $\\mu$m cavity resulting in a Rabi splitting of more than +/- 10 MHz. The presence of sufficient number of atoms in the cavity mode also enabled splitting in the polarization perpendicular to the input. The cavity was in the strong coupling regime, with parameters (g, $\\kappa$, $\\gamma$)/2$\\pi$ equal to (7, 3, 6)/ 2$\\pi$ MHz.

  15. Can magnetic noise from Kondo traps explain high frequency flux noise in superconducting qubits?

    Science.gov (United States)

    Dias da Silva, Luis; de Sousa, Rogerio

    2015-03-01

    In solid state devices, charge and magnetic noise have common microscopic origin. Both occur due to the presence of Kondo traps nearby metallic wires. We use numerical renormalization group calculations to show that, despite their common origin, charge and magnetic noise have opposing behavior controlled by completely different energy scales. While magnetic noise follows an universal scaling with the Kondo temperature, charge noise remains well described by non-interacting theory even when the trap is deep into the Kondo regime. We show how these results may explain the high frequency (f= 1-10 GHz) Ohmic flux noise observed in SQUIDs and superconducting qubits. LGDS acknowledges support from Brazilian agencies FAPESP (2013/50220-7), CNPq (307107/2013-2) and PRP-USP NAP-QNano. RdS acknowledges support from the Canadian program NSERC-Discovery and a FAPESP-UVic exchange award.

  16. Dynamic response of the high flux isotope reactor structure caused by nearby heavy load drop

    International Nuclear Information System (INIS)

    A heavy load of 50,000 lb is assumed to drop from 10 ft above the bottom of the High Flux Isotope Reactor (HFIR) pool at the loading station. The consequences of the dynamic impact to the bottom slab of the pool and to the nearby HFIR reactor vessel are analyzed by applying the ABAQUS computer code The results show that both the BM vessel structure and its supporting legs are subjected to elastic disturbances only and, therefore, will not be damaged. The bottom slab of the pool, however, will be damaged to about half of the slab thickness. The velocity response spectrum at the concrete floor next to the HFIR vessel as a result of the vibration caused by the impact is obtained. It is concluded, that the damage caused by heavy load drop at the loading station is controlled by the slab damage and the nearby HFIR vessel and the supporting legs will not be damaged

  17. Searches for high frequency variations in the 8-B neutrino flux at the Sudbury neutrino observatory

    International Nuclear Information System (INIS)

    We have peformed three searches for high-frequency signals in the solar neutrino flux measured by the Sudbury Neutrino Observatory (SNO), motivated by the possibility that solar g-mode oscillations could affect the production or propagation of solar 8B neutrinos. The first search looked for any significant peak in the frequency range l/day to 144/day, with a sensitivity to sinusoidal signals with amplitudes of 12% or greater. The second search focused on regions in which g-mode signals have been claimed by experiments aboard the SoHO satellite, and was sensitive to signals with amplitudes of 10% or greater. The third search looked for extra power across the entire frequency band. No statistically significant signal was detected in any of the three searches.

  18. Calculational study on irradiation of americium fuel samples in the Petten High Flux Reactor

    International Nuclear Information System (INIS)

    A calculational study on the irradiation of americium samples in the Petten High Flux Reactor (HFR) has been performed. This has been done in the framework of the international EFTTRA cooperation. For several reasons the americium in the samples is supposed to be diluted with a neutron inert matrix, but the main reason is to limit the power density in the sample. The low americium nuclide density in the sample (10 weight % americium oxide) leads to a low radial dependence of the burnup. Three different calculational methods have been used to calculate the burnup in the americium sample: Two-dimensional calculations with WIMS-6, one-dimensional calculations with WIMS-6, and one-dimensional calculations with SCALE. The results of the different methods agree fairly well. It is concluded that the radiotoxicity of the americium sample can be reduced upon irradiation in our scenario. This is especially the case for the radiotoxicity between 100 and 1000 years after storage. (orig.)

  19. Large break loss-of-coolant accident analyses for the high flux isotope reactor

    International Nuclear Information System (INIS)

    The US Department of Energy's High Flux Isotope Reactor (HFIR) was analyzed to evaluate it's response to a spectrum of loss-of-coolant accidents (LOCAs) with potential for leading to core damage. The MELCOR severe accident analysis code (version 1.7.1) was used to evaluate the overall dynamic response of HFIR. Before conducting LOCA analyses, the steady-state thermal-hydraulic parameters evaluated by MELCOR for various loop sections were verified against steady-state operating data. Thereafter, HFIR depressurization tests were simulated to evaluate the system pressure change for a given depletion in coolant inventory. Interesting and important safety-related phenomena were observed. The current analyses (which should be considered preliminary) that occur over a period from 1 to 3 seconds do not lead to core wide fuel melting. Core fluid flashing during the initial rapid depressurization does cause fuel temperature excursions due to adiabatic-like heatup. 3 refs., 4 figs

  20. Observation of high heat flux boiling structures in a horizontal pool by a total reflection technique

    International Nuclear Information System (INIS)

    The experiments were carried out for a horizontal pool boiling of saturated water using a transparent ITO heating surface. Details of boiling structure near the heated surface have been clearly observed by applying the total reflection and diagonal view techniques in a synchronized manner. Mechanisms for the bubble coalescence and dry area expansion processes were clearly identified. The base of the large massive bubble was mostly dry with some trapped liquid. The appearance of this large dry area at high heat flux close to CHF was basically resulted from the multiple steps of bubble coalescences which occur while the bubbles are growing, attached to the boiling surface not before they depart from the boiling surface. The thin liquid layer with distributed vapor stems was not observed under the large massive bubble. (author)

  1. Efforts to Reduce Radioactive Wastes at High Flux Advanced Neutron Application Reactor (HANARO) in Korea

    International Nuclear Information System (INIS)

    The High-flux Advanced Neutron Application Reactor (HANARO) has the equipment to treat the gaseous radioactive waste generated within itself but it does not have proper ways to treat the waste in either a liquid or solid form. For the last 5 years, every effort has been made to reduce the radioactive wastes in HANARO. Improvements of the equipment and operating procedures regarding the generation of radioactive waste in the field have resulted in an effective reduction of the radioactive waste. In addition, as an outgrowth of the research efforts in connection with the demand in the field, several new methods have been developed to effectively treat the radioactive waste. Efforts to reduce and treat the radioactive waste in HANARO will continue and that will contribute greatly to an improvement of the reliability and safety of HANARO. (authors)

  2. Facility modification for severe accident mitigation at the High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    As a part of the recently completed Safety Analysis Report (SAR) for the High Flux Isotope Reactor (HFIR), a detailed MELCOR model was developed for use in the analysis of selected events that lead to core damage. This detailed MELCOR model included the HFIR's reactor coolant system, dynamic confinement, building and yard piping, and a model of the outside waste collection storage tanks. Analyses of several accident sequences involving large breaks in the cold leg piping in the heat exchanger cells and pipe tunnel were conducted with the model. From the results of these simulations, a need for modification of the HFIR confinement was identified. These confinement modifications resulted in over a 12 hour delay in the release of primary system water (an any fission products it contains) outside of the HFIR confinement. This delay would provide valuable time to prevent or mitigate any releases to the environment due to a break in the primary system of the HFIR

  3. Reactor vessel dismantling at the high flux materials testing reactor Petten

    International Nuclear Information System (INIS)

    The project of replacing the reactor vessel of the high flux materials testing reactor (HFR) originated in 1974 when results of several research programs confirmed severe neutron embrittlement of aluminium alloys suggesting a limited life of the existing facility. This report describes the dismantling philosophy and organisation, the design of special underwater equipment, the dismantling of the reactor vessel and thermal column, and the conditioning and shielding activities resulting in a working area for the installation of the new vessel with no access limitations due to radiation. Finally an overview of the segmentation, waste disposal and radiation exposure is given. The total dismantling, segmentation and conditioning activities resulted in a total collective radiation dose of 300 mSv. (orig.)

  4. Flow and heat transfer characteristics of helium cooled IFMIF High Flux Test Module

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yuming, E-mail: Yuming.chen@kit.edu [Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Arbeiter, Frederik [Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2012-08-15

    The International Fusion Materials Irradiation Facility (IFMIF) is designated to generate a materials irradiation database for the future fusion reactors. The High Flux Test Module (HFTM) is located behind the lithium target where a structural damage rate of more than 20 dpa/fpy in steel specimen will be achieved in a volume of about 0.5 l. This paper concerns the thermo-hydraulic simulations of the HFTM with Ansys-CFX. The simulation domain consists of the whole HFTM with short fluid inlet and outlet sections. The turbulence models were assessed by comparing the simulations with in-house annular channel experiments. The flow distributions and heat transfer characteristics among various HFTM sub-channels are the main focuses of this study.

  5. Lay-out activities for the IFMIF high flux test module

    International Nuclear Information System (INIS)

    Nuclear and thermal-hydraulic analyses have been performed with the objective to further optimise the high-flux-test-module (HFTM) design. The nuclear analyses showed that the volume of 0.5 l with a damage rate dpa/fpy>20 can be achieved, if the HFTM has a contour like a semi ellipsoid. The thermal-hydraulic analyses focused on the experimental validation of the helium cooling concept. Integral heat transfer experiments revealed that the specimens can be kept at temperatures up to 600 deg. C. Dedicated experiments are being designed with the objective to provide data for the validation of the direct numeric FE simulation of the helium flow field, the heat transfer and the pressure losses

  6. Flow and heat transfer characteristics of helium cooled IFMIF High Flux Test Module

    International Nuclear Information System (INIS)

    The International Fusion Materials Irradiation Facility (IFMIF) is designated to generate a materials irradiation database for the future fusion reactors. The High Flux Test Module (HFTM) is located behind the lithium target where a structural damage rate of more than 20 dpa/fpy in steel specimen will be achieved in a volume of about 0.5 l. This paper concerns the thermo-hydraulic simulations of the HFTM with Ansys-CFX. The simulation domain consists of the whole HFTM with short fluid inlet and outlet sections. The turbulence models were assessed by comparing the simulations with in-house annular channel experiments. The flow distributions and heat transfer characteristics among various HFTM sub-channels are the main focuses of this study.

  7. Aging, maintenance and modernization of instrumentation at the ORNL High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    This paper describes actions taken at ORNL to upgrade and modernize systems associated with the High Flux Isotope Reactor (HFIR). Three systems are described. The first is a redesigned resistance temperature device commonly used as a temperature detector at HFIR. The aging of existing devices, and lack of spare devices prompted the redesign of new temperature sensors which used commercial grade sensors in a redesigned assembly which allows easier maintenance. The second is a newly designed neutron detector system to replace existing aging devices. The new design uses commercial ionization chambers, in a cheaper, simpler, and less complicated design which could fit in the previous space, and provide monitoring for control and for protection. The third is the development and implementation of a new test procedure for checking the safety performance of the magnetic safety rod release system. This new procedure allows for electronic testing of the modules with considerably lessened chances that a rod will be dropped during the weekly testing

  8. Investigating the use of nanofluids to improve high heat flux cooling systems

    CERN Document Server

    Barrett, T R; Flinders, K; Sergis, A; Hardalupas, Y

    2013-01-01

    The thermal performance of high heat flux components in a fusion reactor could be enhanced significantly by the use of nanofluid coolants, suspensions of a liquid with low concentrations of solid nanoparticles. However, before they are considered viable for fusion, the long-term behaviour of nanofluids must be investigated. This paper reports an experiment which is being prepared to provide data on nanofluid stability, settling and erosion in a HyperVapotron device. Procedures are demonstrated for nanofluid synthesis and quality assessment, and the fluid sample analysis methods are described. The end results from this long-running experiment are expected to allow an initial assessment of the suitability of nanofluids as coolants in a fusion reactor.

  9. High-latitude poynting flux from combined Iridium and SuperDARN data

    Directory of Open Access Journals (Sweden)

    C. L. Waters

    2004-09-01

    Full Text Available Field-aligned currents convey stress between the magnetosphere and ionosphere, and the associated low altitude magnetic and electric fields reflect the flow of electromagnetic energy to the polar ionosphere. We introduce a new technique to measure the global distribution of high latitude Poynting flux, S||, by combining electric field estimates from the Super Dual Auroral Radar Network (SuperDARN with magnetic perturbations derived using magnetometer data from the Iridium satellite constellation. Spherical harmonic methods are used to merge the data sets and calculate S|| for any magnetic local time (MLT from the pole to 60° magnetic latitude (MLAT. The effective spatial resolutions are 2° MLAT, 2h MLT, and the time resolution is about one hour due to the telemetry rate of the Iridium magnetometer data. The technique allows for the assessment of high-latitude net S|| and its spatial distribution on one hour time scales with two key advantages: (1 it yields the net S|| including the contribution of neutral winds; and (2 the results are obtained without recourse to estimates of ionosphere conductivity. We present two examples, 23 November 1999, 14:00-15:00 UT, and 11 March 2000, 16:00-17:00 UT, to test the accuracy of the technique and to illustrate the distributions of S|| that it gives. Comparisons with in-situ S|| estimates from DMSP satellites show agreement to a few mW/m2 and in the locations of S|| enhancements to within the technique's resolution. The total electromagnetic energy flux was 50GW for these events. At auroral latitudes, S|| tends to maximize in the morning and afternoon in regions less than 5° in MLAT by two hours in MLT having S||=10 to 20mW/m2 and total power up to 10GW. The power poleward of the Region 1 currents is about one

  10. High-latitude electromagnetic and particle energy flux during an event with sustained strongly northward IMF

    Directory of Open Access Journals (Sweden)

    H. Korth

    2005-06-01

    Full Text Available We present a case study of a prolonged interval of strongly northward orientation of the interplanetary magnetic field on 16 July 2000, 16:00-19:00 UT to characterize the energy exchange between the magnetosphere and ionosphere for conditions associated with minimum solar wind-magnetosphere coupling. With reconnection occurring tailward of the cusp under northward IMF conditions, the reconnection dynamo should be separated from the viscous dynamo, presumably driven by the Kelvin-Helmholtz (KH instability. Thus, these conditions are also ideal for evaluating the contribution of a viscous interaction to the coupling process. We derive the two-dimensional distribution of the Poynting vector radial component in the northern sunlit polar ionosphere from magnetic field observations by the constellation of Iridium satellites together with drift meter and magnetometer observations from the Defense Meteorological Satellite Program (DMSP F13 and F15 satellites. The electromagnetic energy flux is then compared with the particle energy flux obtained from auroral images taken by the far-ultraviolet (FUV instrument on the Imager for Magnetopause to Aurora Global Exploration (IMAGE spacecraft. The electromagnetic energy input to the ionosphere of 51 GW calculated from the Iridium/DMSP observations is eight times larger than the 6 GW due to particle precipitation all poleward of 78° MLAT. This result indicates that the energy transport is significant, particularly as it is concentrated in a small region near the magnetic pole, even under conditions traditionally considered to be quiet and is dominated by the electromagnetic flux. We estimate the contributions of the high and mid-latitude dynamos to both the Birkeland currents and electric potentials finding that high-latitude reconnection accounts for 0.8 MA and 45kV while we attribute <0.2MA and ~5kV to an interaction at lower latitudes having the sense of a viscous interaction. Given that these

  11. The High Flux Isotope Reactor (HFIR) cold source project at ORNL

    International Nuclear Information System (INIS)

    Following the decision to cancel the Advanced Neutron Source (ANS) Project at Oak Ridge National Laboratory (ORNL), it was determined that a hydrogen cold source should be retrofitted into an existing beam tube of the High Flux Isotope Reactor (HFIR) at ORNL. The preliminary design of this system has been completed and an 'approval in principle' of the design has been obtained from the internal ORNL safety review committees and the U.S. Department of Energy (DOE) safety review committee. The cold source concept is basically a closed loop forced flow supercritical hydrogen system. The supercritical approach was chosen because of its enhanced stability in the proposed high heat flux regions. Neutron and gamma physics of the moderator have been analyzed using the 3D Monte Carlo code MCNP1 A D structural analysis model of the moderator vessel, vacuum tube, and beam tube was completed to evaluate stress loadings and to examine the impact of hydrogen detonations in the beam tube. A detailed ATHENA2 system model of the hydrogen system has been developed to simulate loop performance under normal and off-normal transient conditions. Semi-prototypic hydrogen loop tests of the system have been performed at the Arnold Engineering Design Center (AEDC) located in Tullahoma, Tennessee to verify the design and benchmark the analytical system model. A 3.5 kW refrigerator system has been ordered and is expected to be delivered to ORNL by the end of this calendar year. Our present schedule shows the assembling of the cold source loop on site during the fall of 1999 for final testing before insertion of the moderator plug assembly into the reactor beam tube during the end of the year 2000. (author)

  12. Heat transfer augmentation for high heat flux removal in rib-roughened narrow channels

    International Nuclear Information System (INIS)

    Heat transfer augmentation in narrow rectangular channels in a target system is a very important method to remove high heat flux up to 12 MW/m2 generated at target plates of a high-intensity proton accelerator of 1.5 GeV and 1 mA with a proton beam power of 1.5 MW. In this report, heat transfer coefficients and friction factors in narrow rectangular channels with one-sided rib-roughened surface were evaluated for fully developed flows in the range of the Reynolds number from 6,000 to 1,00,000; the rib pitch-to-height ratios (p/k) were 10,20 and 30; the rib height-to-equivalent diameter ratios (k/De) were 0.025, 0.03 and 0.1 by means of previous existing experimental correlations. The rib-roughened surface augmented heat transfer coefficients approximately 4 times higher than the smooth surface at Re=10,000, p/k=10 and k/De=0.1; friction factors increase around 22 times higher. In this case, higher heat flux up to 12 MW/m2 could be removed from the rib-roughened surface without flow boiling which induces flow instability; but pressure drop reaches about 1.8 MPa. Correlations obtained by air-flow experiments have showed lower heat transfer performance with the water-flow conditions. The experimental apparatus was proposed for further investigation on heat transfer augmentation in very narrow channels under water-flow conditions. This report presents the evaluation results and an outline of the test apparatus. (author)

  13. Elaboration of mini plates with U-Mo for irradiation in a high flux reactor

    International Nuclear Information System (INIS)

    Full text: International new efforts for the reconversion of HEU in research, testing and radioisotopes production reactors, have greatly incremented U-Mo fuels qualification activities. These qualifications require the resolution of undesired interaction at high fluxes between UMo particles and the aluminum matrix in the case of dispersed fuels and the development of U-Mo monolithic fuels. These efforts are being manifested in the planning and execution of additional series of irradiation tests of mini plates and full size plates. Recently, CNEA has elaborated mini plates with different proposals for the irradiation at the ATR reactor (250 MWTH, maximum thermal neutron flux 1015 n.cm-2.seg-1) at Idaho National Laboratory, USA. Uranium 7% (w/w) molybdenum (U-7Mo) particles were coated with silicon. Chemical vapour deposition (CVD) of silane and high temperature diffusion of silicon were used. Hydrided, milled and dehydrated (HMD) particles heat treated at 1000 C degrees during four hours and centrifugal atomized powder were coated and the results compared. Mini plates were elaborated with both kinds of particles. Mini plates were also elaborated with U-7Mo and silicon particles dispersed in the aluminium matrix. Monolithic mini plates were also developed by co lamination of U-7Mo with a Zircaloy-4 cladding. The different steps of this process are detailed and the method is shown to be versatile, can be easily scaled up and is performed with small modifications of usual equipment in fuel plants. The irradiation experiment is called RERTR-7A, includes a total of 32 mini plates and it is planed to finalize by mid 2006. (author)

  14. High heat flux actively cooled plasma facing components development, realisation and first results in Tore Supra

    International Nuclear Information System (INIS)

    The development, design, manufacture and testing of actively cooled high heat flux (HHF) plasma facing components (PFCs) has been an essential part of the Tore Supra programme towards long powerful tokamak operation. The Tore Supra PFC programme has culminated in the installation and operation of a toroidal pump limiter, since 2002, which already allowed to reach new world records in steady state operation (1 GJ injected in a 6 min discharge). The HHF PFCs development and manufacturing was achieved through a long lead development and industrialisation programme (about 10 years) marked out with a number of challenges. The major technical topics cope with bonding technology analysis involving an adequate material selection and procurement, repair processes development and implementation, development of destructive and non-destructive testing methods, and more generally industrialisation assessment. All these lessons are relevant to the ITER divertor PFCs manufacturing, although the technical solution adopted for Tore Supra (flat tiles concept) is different from the one proposed for the ITER divertor (monoblock concept). The routine operation of the actively cooled toroidal pumped limiter (TPL), capable to sustain up to 10 MW m-2 of nominal convected heat flux, is described. Up to now, the limiter fulfills its objectives in terms of heat exhaust. However, the thermographic monitoring exhibits unexpected behavior of the surface temperature. Particle exhaust control displays a complex pattern, due to the high fraction of the injected deuterium, which remains in the wall. The first experimental results with a full actively cooled wall gives access to ITER relevant information on wall conditioning, hydrogen plasma density and vacuum vessel inventory control, carbon erosion and redeposition and capability of in situ monitoring in a completely actively cooled environment

  15. Carbon-carbon composite and copper-composite bond damages for high flux component controlled fusion

    International Nuclear Information System (INIS)

    Plasma facing components constitute the first wall in contact with plasma in fusion machines such as Tore Supra and ITER. These components have to sustain high heat flux and consequently elevated temperatures. They are made up of an armour material, the carbon-carbon composite, a heat sink structure material, the copper chromium zirconium, and a material, the OFHC copper, which is used as a compliant layer between the carbon-carbon composite and the copper chromium zirconium. Using different materials leads to the apparition of strong residual stresses during manufacturing, because of the thermal expansion mismatch between the materials, and compromises the lasting operation of fusion machines as damage which appeared during manufacturing may propagate. The objective of this study is to understand the damage mechanisms of the carbon-carbon composite and the composite-copper bond under solicitations that plasma facing components may suffer during their life. The mechanical behaviours of carbon-carbon composite and composite-copper bond were studied in order to define the most suitable models to describe these behaviours. With these models, thermomechanical calculations were performed on plasma facing components with the finite element code Cast3M. The manufacturing of the components induces high stresses which damage the carbon-carbon composite and the composite-copper bond. The damage propagates during the cooling down to room temperature and not under heat flux. Alternative geometries for the plasma facing components were studied to reduce damage. The relation between the damage of the carbon-carbon composite and its thermal conductivity was also demonstrated. (author)

  16. Status of the visible Free-Electron Laser at the Brookhaven Accelerator Test Facility

    International Nuclear Information System (INIS)

    The 500 nm Free-Electron Laser (ATF) of the Brookhaven National Laboratory is reviewed. We present an overview of the ATF, a high-brightness, 50-MeV, electron accelerator and laser complex which is a users' facility for accelerator and beam physics. A number of laser acceleration and FEL experiments are under construction at the ATF. The visible FEL experiment is based on a novel superferric 8.8 mm period undulator. The electron beam parameters, the undulator, the optical resonator, optical and electron beam diagnostics are discussed. The operational status of the experiment is presented. 22 refs., 7 figs

  17. Superconducting magnet program for X-Ray Lithography source at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Brookhaven National Laboratory is funded by DOD-DARPA to develop a compact electron storage ring to be used as a X-Ray source for producing high density computer chips. The circumference of this machine is 8.5 meters, the machine lattice consists of four quadrupoles, two sextupoles and a pair of air-core combined function 3.87 Tesla superconducting dipoles. BNL is developing the superconducting dipoles in collaboration with its industrial partners GDSSD and GSED. This paper will describe the field characteristics and engineering realization of these magnets and present the current status of the program

  18. Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion sourcea)

    Science.gov (United States)

    Kondo, K.; Yamamoto, T.; Sekine, M.; Okamura, M.

    2012-02-01

    The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (˜100 μA) with high charge (˜10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

  19. Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion source

    International Nuclear Information System (INIS)

    The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (∼100 μA) with high charge (∼10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

  20. Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion source.

    Science.gov (United States)

    Kondo, K; Yamamoto, T; Sekine, M; Okamura, M

    2012-02-01

    The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (∼100 μA) with high charge (∼10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline. PMID:22380298

  1. Thermoresponsive Ultrathin Membranes with Precisely Tuned Nanopores for High-Flux Separation.

    Science.gov (United States)

    Zhu, Yuzhang; Gao, Shoujian; Hu, Liang; Jin, Jian

    2016-06-01

    With the growing demand for small- and large-scale bioprocesses, advanced membranes with high energy efficiency are highly required. However, conventional polymer-based membranes often have to sacrifice selectivity for permeability. In this work, we report the fabrication of a thermoresponsive composite ultrathin membrane with precisely controlled nanopores for high-throughput separation. The composite membrane is made by grafting a PEG analogue thermoresponsive copolymer onto an ultrathin single-wall carbon nanotubes (SWCNTs) membrane via π-π interaction with no use of the common "grafting from" synthesis approach. The composite membrane exhibits ultrahigh water permeation flux as high as 6430 L m(-2) h(-1) at 40 °C, and more importantly, the pore size of the membrane could be finely adjusted by utilizing the thermoresponsive property of the grafted copolymer. With the temperature changing below and above the lower critical solution temperature (LCST) of the copolymer, the effective pore size of the membrane can be tuned precisely between approximately 12 and 14 nm, which could be applied to effectively separate materials with very small size differences through size sieving. PMID:27177239

  2. Design and performance of vacuum system for high heat flux test facility

    International Nuclear Information System (INIS)

    High heat flux test facility (HHFTF) at IPR is used for testing thermal performance of plasma facing material or components. It consists of various subsystems like vacuum system, high power electron beam system, diagnostic and calibration system, data acquisition and control system and high pressure high temperature water circulation system. Vacuum system consists of large D-shaped chamber, target handling system, pumping systems and support structure. The net volume of vacuum chamber is 5m3 was maintained at the base pressure of the order of 10-6 mbar for operation of electron gun with minimum beam diameter. Inorder to achieve the ultimate vacuum, turbo-molecular pump (TMP) and cryo pump are installed. Each TMP and cryo-pump unit has an electro-pneumatic gate valve of respective size to isolate the pump in the case of either vacuum break in the D-shaped chamber or in case of the pump failure to protect each in either condition. A variable conductance gate valve is used for maintaining required vacuum in the chamber. Initial pumping of the chamber was carried out by using suitable rotary and root pumps. PXI and PLC based faster real time data acquisition and control system is implemented for performing the various operations like remote operation, online vacuum data measurements, display and status indication of all vacuum equipments. This paper describes in detail the design and implementation of various vacuum subsystems including relevant experimental details. (author)

  3. Design of small-animal thermal neutron irradiation facility at the Brookhaven Medical Research Reactor

    International Nuclear Information System (INIS)

    The broad beam facility (BBF) at the Brookhaven Medical Research Reactor (BMRR) can provide a thermal neutron beam with flux intensity and quality comparable to the beam currently used for research on neutron capture therapy using cell-culture and small-animal irradiations. Monte Carlo computations were made, first, to compare with the dosimetric measurements at the existing BBF and, second, to calculate the neutron and gamma fluxes and doses expected at the proposed BBF. Multiple cell cultures or small animals could be irradiated simultaneously at the so-modified BBF under conditions similar to or better than those individual animals irradiated at the existing thermal neutron irradiation Facility (TNIF) of the BMRR. The flux intensity of the collimated thermal neutron beam at the proposed BBF would be 1.7 x 1010 n/cm2·s at 3-MW reactor power, the same as at the TNIF. However, the proposed collimated beam would have much lower gamma (0.89 x 10-11 cGy·cm2/nth) and fast neutron (0.58 x 10-11 cGy·cm2/nth) contaminations, 64 and 19% of those at the TNIF, respectively. The feasibility of remodeling the facility is discussed

  4. Development of a high-heat-flux target for multimegawatt, multisecond neutral beams at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Combs, S.K.; Milora, S.L.; Bush, C.E.; Foster, C.A.; Haselton, H.H.; Hayes, P.H.; Menon, M.M.; Moeller, J.A.; Sluss, F.; Tsai, C.C.

    1984-01-01

    A high-heat-flux target has been developed for intercepting multimegawatt, multisecond neutral beam power at the Oak Ridge National Laboratory (ORNL). Water-cooled copper swirl tubes are used for the heat transfer medium; these tubes exhibit an enhancement in burnout heat flux over conventional axial-flow tubes. The target consists of 126 swirl tubes (each 0.95 cm in outside diameter with 0.16-cm-thick walls and approx. =1 m long) arranged in a V-shape. Two arrays of parallel tubes inclined at an angle ..cap alpha.. to the beam axis form the V-shape, and this geometry reduces the surface heat flux by a factor of 1/sin ..cap alpha.. (for the present design, ..cap alpha.. =13/sup 0/ and 21/sup 0/). In tests with the ORNL long-pulse ion source (13- by 43-cm grid), the target has handled up to 3-MW, 30-s beam pulses with no deleterious effects. The peak power density was estimated at approx. =15 kW/cm/sup 2/ normal to the beam axis (5.4 kW/cm/sup 2/ maximum on tube surfaces). The water flow rate through the target was 41.6 L/s (660 gpm) or 0.33 L/s (5.2 gpm) per tube (axial flow velocity = 11.6 m/s). The corresponding pressure drop across the target was 1.14 MPa (165 psi) with an inlet pressure of 1.45 MPa (210 psia). Data are also presented from backup experiments in which individual tubes were heated by a small ion source (10-cm-diam grid) to characterize tube performance. These results suggest that the target should handle peak power densities in the range 25 to 30 kW/cm/sup 2/ normal to the beam axis (approx. =10 kW/cm/sup 2/ maximum on tube surfaces) with the present flow parameters. This translates to beam power levels of 5 to 6 MW for equivalent beam optics.

  5. Effects of Temperature Gradients and Heat Fluxes on High-Temperature Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, G.R.

    2008-04-01

    The effects of a temperature gradient and heat flux on point defect diffusion in protective oxide scales were examined. Irreversible thermodynamics were used to expand Fick’s first law of diffusion to include a heat-flux term—a Soret effect. Oxidation kinetics were developed for the oxidation of cobalt and of nickel doped with chromium. Research is described to verify the effects of a heat flux by oxidizing pure cobalt in a temperature gradient at 900 °C, and comparing the kinetics to isothermal oxidation. No evidence of a heat flux effect was found.

  6. Calculation of the neutron flux variation and the reactivity by high order perturbation theory

    International Nuclear Information System (INIS)

    A perturbative formulation, independent of time, with approximation to higher orders is presented. Equations are obtained for the reactivity and neutron flux variations to any desired order, through the use of neutron flux difference equations (perturbed flux minus imperturbed flux ) and the application of the expansion in power series method. The solution of these equations is obtained using the neutron-life-cycle technique. Tests were made to verify the relevance of the higher-order terms contribution to the reactivity variation for a given perturbation and for a steady-state PWR reactor, fueled with UO2, with 2.6% of enrichment. (E.G.)

  7. Direct relationship between trapped magnetic flux characteristics and percolation transition temperature in a practical sized bulk high-temperature superconductor

    International Nuclear Information System (INIS)

    The trapped magnetic flux characteristics of a Gd-system bulk high-Tc superconductor (HTS) near the so-called percolation transition temperature was investigated experimentally. The percolation transition temperature was directly determined from the temperature dependence of the E-J characteristics with a bar-shaped HTS. Next, the disc-shaped bulk HTS sample was magnetized by means of a field-cooling process, and then the decay of the trapped magnetic flux density was monitored for 30 min after the exciting current of the electromagnet was cut off. It was shown that the decay rate of trapped magnetic flux changed considerably around the percolation transition temperature. Furthermore, the trapped flux showed stepwise decay, and these phenomena could explain the percolation mechanism of the depinning process. From our study, the percolation temperature may be utilized for the limit parameter in order to design application systems with a practical sized bulk HTS

  8. Application of the AN-17M and AN-43 fluxes to welding of high-tensile steels

    International Nuclear Information System (INIS)

    The application experience of low-siliceous fluxes with an increased content of iron oxides used for welding the steels of the increased and high strength is considered. It is shown that in combination with certain grades of welding wire the considered fluxes ensure sufficient mechanical properties and impact viscosity in the course of welding carbon, chromium-molybdenum and nickel-chromium steels. In a number of cases the welded joints made by these fluxes without additional heat treatment are equal to the base metal in all the characteristics including fracture toughness and resistance to a spreading crack at negative temperature. The fluxes proved to be good at the welding of parogenerator casing for nuclear energy plants, pipe-lines, pressure vessels and also heavy-loaded constructions

  9. High Heat flux (HHF) elements for Negative Ion Systems on ITER

    International Nuclear Information System (INIS)

    Negative Ion Neutral Beam systems on ITER will require actively cooled scrapers and dumps to process and shape the beam before injection into the tokamak. The scale of the systems is much larger than any presently operating, bringing challenges for designers in terms of available sub cooling, total pressure drop, deflection and mandatory remote maintenance. In common with Positive Ion systems, flux densities in the order of 15-20 MW/m2 are commonplace but with much longer pulses. A pulse length in excess of 3000 seconds and the anticipated beam breakdown rate pose new challenges in terms of stress and fatigue life. The cooling system specification (up to 26 bar, 80 oC) adds further constraints impacting the material choice and operating temperature. The DDD designs, based on swirl tubes, have been reviewed as part of the design process and recommendations made. Additionally, alternative designs have been proposed based on the Hypervapotron high heat flux elements with modified geometry and drawing upon a vast background knowledge of large scale equipment procurement and integration. Existing operational and design experience has been applied to give a simple, robust and low maintenance alternative. A full thermomechanical analysis of all HHF components has been undertaken based on ITER design criteria and the limited material data available. The results of this analysis will be presented, highlighting areas where further R(and)D is necessary to reach the operating limits set out in the functional specification. Extensive comparison of these analyses is made with the large operational database of existing JET beamline components for benchmarking purposes. A particular feature of the thermo-mechanical analyses is a fully self-consistent description in which ageing characteristics are related to the local temperature, and the components' power loading takes into account the thermal distortion. The advantages and disadvantages of all designs will be presented and

  10. Bidirectional flux of cholesterol between cells and lipoproteins. Effects of phospholipid depletion of high density lipoprotein

    International Nuclear Information System (INIS)

    The bidirectional surface transfer of free cholesterol (FC) between Fu5AH rat hepatoma cells and human high density lipoprotein (HDL) was studied. Cells and HDL were prelabeled with [4-14C]FC and [7-3H]FC, respectively. Influx and efflux of FC were measured simultaneously from the appearance of 3H counts in cells and 14C counts in medium. Results were analyzed by a computerized procedure which fitted sets of kinetic data to a model assuming that cell and HDL FC populations each formed a single homogeneous pool and that together the pools formed a closed system. This analysis yielded values for the first-order rate constants of FC influx and efflux (ki and ke), from which influx and efflux of FC mass (Fi and Fe) could be calculated. With normal HDL, the uptake and release of FC tracers conformed well to the above-described model; Fi and Fe were approximately equal, suggesting an exchange of FC between cells and HDL. HDL was depleted of phospholipid (PL) by treatment with either phospholipase A2 or heparin-releasable rat hepatic lipase, followed by incubation with bovine serum albumin. PL depletion of HDL had little or no effect on ki, but reduced ke, indicating that PL-deficient HDL is a relatively poor acceptor of cell cholesterol. The reduction in ke resulted in initial Fi greater than Fe and, thus, in net uptake of FC by the cells. This result explained previous results demonstrating net uptake of FC from PL-depleted HDL. In the presence of an inhibitor of acyl coenzyme A:cholesterol acyltransferase, the steady state distribution of FC mass between cells and HDL was accurately predicted by the ratio of rate constants for FC flux. This result provided additional validation for describing FC flux in terms of first-order rate constants and homogeneous cell and HDL FC pools

  11. Hard Pomeron Enhanced Cascade Production and Flux Shadowing in High-Energy Neutrino Astrophysics

    CERN Document Server

    Gazizov, A Z

    2002-01-01

    Various implications of new, non-perturbative pomeron inspired enhancement of small-x neutrino-nucleon structure functions for high-energy neutrino astrophysics are discussed. At x larger than 10^{-5} these functions are given by perturbative QCD, while at lower x they are determined by a specific generalization of F_2^{ep}(x,Q^2) description, proposed by A. Donnachie and P. V. Landshoff (their two-component model comprises hard and soft pomerons), to neutrino-nucleon scattering case. We found that i) such enhancement causes the most rapid growth of neutrino-nucleon cross-sections at high energies, ii) pomeron effects may be perceptible in the rates of neutrino induced events in future giant detectors and iii) the rate of high-energy neutrino flux evolution (due to absorption (CC+NC) and regeneration (NC)) on its pass through a large column depth of matter may be subjected to additional influence of hard pomeron. Solving transport equations for the initially power-law decreasing neutrino spectra, we have eval...

  12. Next generation fuel irradiation capability in the High Flux Reactor Petten

    International Nuclear Information System (INIS)

    This paper describes selected equipment and expertise on fuel irradiation testing at the High Flux Reactor (HFR) in Petten, The Netherlands. The reactor went critical in 1961 and holds an operating license up to at least 2015. While HFR has initially focused on Light Water Reactor fuel and materials, it also played a decisive role since the 1970s in the German High Temperature Reactor (HTR) development program. A variety of tests related to fast reactor development in Europe were carried out for next generation fuel and materials, in particular for Very High Temperature Reactor (V/HTR) fuel, fuel for closed fuel cycles (U-Pu and Th-U fuel cycle) and transmutation, as well as for other innovative fuel types. The HFR constitutes a significant European infrastructure tool for the development of next generation reactors. Experimental facilities addressed include V/HTR fuel tests, a coated particle irradiation rig, and tests on fast reactor, transmutation and thorium fuel. The rationales for these tests are given, results are provided and further work is outlined.

  13. Industrialization of nanocrystalline Fe-Si-B-P-Cu alloys for high magnetic flux density cores

    Science.gov (United States)

    Takenaka, Kana; Setyawan, Albertus D.; Sharma, Parmanand; Nishiyama, Nobuyuki; Makino, Akihiro

    2016-03-01

    Nanocrystalline Fe-Si-B-P-Cu alloys exhibit high saturation magnetic flux density (Bs) and extremely low magnetic core loss (W), simultaneously. Low amorphous-forming ability of these alloys hinders their application potential in power transformers and motors. Here we report a solution to this problem. Minor addition of C is found to be effective in increasing the amorphous-forming ability of Fe-Si-B-P-Cu alloys. It allows fabrication of 120 mm wide ribbons (which was limited to less than 40 mm) without noticeable degradation in magnetic properties. The nanocrystalline (Fe85.7Si0.5B9.5P3.5Cu0.8)99C1 ribbons exhibit low coercivity (Hc)~4.5 A/m, high Bs~1.83 T and low W~0.27 W/kg (@ 1.5 T and 50 Hz). Success in fabrication of long (60-100 m) and wide (~120 mm) ribbons, which are made up of low cost elements is promising for mass production of energy efficient high power transformers and motors

  14. The use of intelligent modules in Brookhaven FASTBUS

    International Nuclear Information System (INIS)

    Many considerations go into the design of modules for data acquisition. I address some of the more general aspects of this rather than the specifics of a particular design. The experience gained from using Brookhaven Fastbus in two finished experiments and one eminent one is used as a guide for these remarks. The physical size of modules used by Brookhaven Fastbus is such that the number of channels that can be handled is generally limited by front panel space, or front end layout logistics rather than area. One of the effects of large scale integrated circuits is that the cost of computational elements is relatively small. This, plus the space consideration, allows the assignment of low level data processing to the acquisition modules. Since these elements operate in parallel there is an obvious speed advantage

  15. BROOKHAVEN NATIONAL LABORATORY INSTITUTIONAL PLAN FY2003-2007.

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-06-10

    This document presents the vision for Brookhaven National Laboratory (BNL) for the next five years, and a roadmap for implementing that vision. Brookhaven is a multidisciplinary science-based laboratory operated for the U.S. Department of Energy (DOE), supported primarily by programs sponsored by the DOE's Office of Science. As the third-largest funding agency for science in the U.S., one of the DOE's goals is ''to advance basic research and the instruments of science that are the foundations for DOE's applied missions, a base for U.S. technology innovation, and a source of remarkable insights into our physical and biological world, and the nature of matter and energy'' (DOE Office of Science Strategic Plan, 2000 http://www.osti.gov/portfolio/science.htm). BNL shapes its vision according to this plan.

  16. Brookhaven Accelerator Test Facility photocathode gun and transport beamline

    International Nuclear Information System (INIS)

    We present an analysis of the electron beam emitted from a laser driven photocathode injector (Gun, operating at 2856 MHZ), through a Transport beamline, to the LINAC entrance for the Brookhaven Accelerator Test Facility (ATF). The beam parameters including beam energy, and emittance are calculated. Some of our results, are tabulated and the phase plots of the beam parameters, from Cathode, through the Transport line elements, to the LINAC entrance, are shown

  17. Operation of the Brookhaven AGS with the Booster

    International Nuclear Information System (INIS)

    The Brookhaven Alternating Gradient Synchrotron (AGS) received protons directly from a Linac and heavy ions directly from a Tandem Van de Graaff before 1992. The newly constructed Booster has been brought on line to serve as an injector for the AGS. The operational status of the acceleration of proton and heavy ions through the Booster and the AGS is reviewed. Accelerator improvement programs to increase proton intensity for physics research and to prepare heavy ion beams for RHIC injection are discussed

  18. Brookhaven National Laboratory's multiparticle spectrometer drift chamber system

    International Nuclear Information System (INIS)

    A system of drift chambers is being built to replace the present spark chambers in the Brookhaven National Laboratory's Multiparticle Spectrometer. This system will handle a beam of approx. 3 million particles per second and have a resolution of 200 μm. A summary of the status of the chambers and the custom integrated circuits is presented. The data acquisition system is described. Prototype chambers have been built and tested with results that are consistent with the expected chamber properties

  19. Carbon flux from plants to soil microbes is highly sensitive to nitrogen addition and biochar amendment

    Science.gov (United States)

    Kaiser, C.; Solaiman, Z. M.; Kilburn, M. R.; Clode, P. L.; Fuchslueger, L.; Koranda, M.; Murphy, D. V.

    2012-04-01

    material, microbial biomass and dissolved organic matter by IRMS, 13C and 15N in plant roots cells and intraradical mycorrhizal hyphae by NanoSims). Our results show that (1) C assimilated by plants was delivered within 4 hours to the soil microbial community both via roots and the mycorrhizal network (2) N addition during the labeling period strongly and rapidly increased the 13C flux of recently assimilated carbohydrates to the soil microbial biomass (3) the effect of N addition was not as rapid but was of the same magnitude when N was delivered to the plant exclusively by mycorrhizal hyphae as compared to taken up by roots (4) soils which had been amended with biochar (which were characterized by an increased abundance of mycorrhizal fungi) also showed a significant increase of C flux from plants to the soil. We conclude that plant belowground C allocation is highly sensitive to alterations of microbial community structure and nutritional status in the soil. Moreover, our results indicate that plants respond rapidly (within hours) to changing soil N availability by altering the rate of C transported belowground. Our results emphasise the ecological significance of plant-belowground interactions for ecosystem C cycling.

  20. Approach to development of high flux research reactor with pebble-bed core

    International Nuclear Information System (INIS)

    Full text: The research nuclear reactor of a basin-type IRT with the designed power of 1 MW was put into operation in 'Sosny' settlement not far from Minsk-city in the Republic of Belarus in 1962. In 1971 after its modernization the power was increased up to 4 MW and maximum density of neutron flux in the core was: Thermal 5·1013 neutr./cm2.s Fast (E>0.8 MeV) 2·1013 neutr./cm2.s The reactor has been used for carrying out investigations in the field of solid-state physics, radiation construction materials, radiobiology, gaseous chemically reacting coolants and others. After the Chernobyl NPP accident, in the former USSR the requirements on safety of nuclear reactors have become sufficiently stricter. As to some parameters these requirements became the same as for reactors of nuclear power plants. In this connection the reactor in 'Sosny' settlement did not answer these new requirements by a number of performances such as seismicity of building, efficiency of control and protection system, corrosion in the reactor vessel and others, and it was shutdown in 1987 and its decommissioning was performed during 1988-1999. At the Joint Institute of Power and Nuclear Research -'SOSNY' have been carried out investigations on feasibility of creation of the research reactor with pebble-bed core. The concept of such reactor supposes using the following technical approaches: - Using as fuel the brought sphere micro fuel elements with the diameter of 500-750 mkm to an industrial level; - Organization of reactor operation in the regime with minimum possible fueling with 235U; - Implementation of hydraulic loading - unloading of micro fuel elements with the frequency of one or several days. Physical calculations of the core were carried out with the help of MCU-RFFI program based on the Monte-Carlo method. Two configurations of the pebble-bed core in the high flux reactor have been considered. The first configuration is the core with a neutron trap and an annular fuel layer formed

  1. Generation of high-photon flux-coherent soft x-ray radiation with few-cycle pulses.

    Science.gov (United States)

    Demmler, Stefan; Rothhardt, Jan; Hädrich, Steffen; Krebs, Manuel; Hage, Arvid; Limpert, Jens; Tünnermann, Andreas

    2013-12-01

    We present a tabletop source of coherent soft x-ray radiation with high-photon flux. Two-cycle pulses delivered by a fiber-laser-pumped optical parametric chirped-pulse amplifier operating at 180 kHz repetition rate are upconverted via high harmonic generation in neon to photon energies beyond 200 eV. A maximum photon flux of 1.3·10(8) photons/s is achieved within a 1% bandwidth at 125 eV photon energy. This corresponds to a conversion efficiency of ~10(-9), which can be reached due to a gas jet simultaneously providing a high target density and phase matching. Further scaling potential toward higher photon flux as well as higher photon energies are discussed. PMID:24281507

  2. Temperature dependence of swelling in Type 316 stainless steel irradiated in HFIR [High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    The temperature dependence of swelling was investigated in solution-annealed (SA) and 20% cold-worked (CW) type 316 stainless steel irradiated to 30 dpa at 300 to 6000C in the High Flux Isotope Reactor (HFIR). At irradiation temperatures ≤ 4000C, a high concentration (2 to 4 x 1023 m-3) of small bubbles (1.5 to 4.5 nm diam) formed uniformly in the matrix. Swelling was low (0C. At 5000C, there was a mixture of bubbles and voids, but at 6000C, most of the cavities were voids. Maximum swelling (∼5%) occurred at 5000C. By contrast, cavities in 20% CW specimens were much smaller, with diameters of 6 and 9 nm at 500 and 6000C, respectively, suggesting that they were primarily bubbles. The cavity number density in the CW 316 at both 500 and 6000C (∼1 x 1022 m-3) was about one order of magnitude less than at 4000C. Swelling increased slightly as irradiation temperature increased, peaking at 6000C (0.3%). These results indicate that SA 316 swells more than CW 316 at 500 and 6000C, but both SA and CW 316 are resistant to void swelling in HFIR at 4000C and below to 30 dpa. 15 refs

  3. Extraction of gadolinium from high flux isotope reactor control plates. [Alternative method

    Energy Technology Data Exchange (ETDEWEB)

    Kohring, M.W.

    1987-04-01

    Gadolinium-153 is an important radioisotope used in the diagnosis of various bone disorders. Recent medical and technical developments in the detection and cure of osteoporosis, a bone disease affecting an estimated 50 million people, have greatly increased the demand for this isotope. The Oak Ridge National Laboratory (ORNL) has produced /sup 153/Gd since 1980 primarily through the irradiation of a natural europium-oxide powder followed by the chemical separation of the gadolinium fraction from the europium material. Due to the higher demand for /sup 153/Gd, an alternative production method to supplement this process has been investigated. This process involves the extraction of gadolinium from the europium-bearing region of highly radioactive, spent control plates used at the High Flux Isotope Reactor (HFIR) with a subsequent re-irradiation of the extracted material for the production of the /sup 153/Gd. Based on the results of experimental and calculational analyses, up to 25 grams of valuable gadolinium (greater than or equal to60% enriched in /sup 152/Gd) resides in the europium-bearing region of the HFIR control components of which 70% is recoverable. At a specific activity yield of 40 curies of /sup 153/Gd for each gram of gadolinium re-irradiated, 700 one-curie sources can be produced from each control plate assayed.

  4. Non-destructive methods for the defect detection in the ITER high heat flux components

    Energy Technology Data Exchange (ETDEWEB)

    Roccella, S., E-mail: selanna.roccella@enea.it [Associazione ENEA-Euratom sulla Fusione C.R.Frascati - 00044-Frascati, RM (Italy); Burrasca, G.; Cacciotti, E. [Associazione ENEA-Euratom sulla Fusione C.R.Frascati - 00044-Frascati, RM (Italy); Castillo, A. [Associazione Euratom-ENEA sulla Fusione, C.R.Casaccia, Via Anguillarese 301-00123 S. Maria di Galeria, RM (Italy); Universidad Politecnica de Valencia, Valencia (Spain); Mancini, A.; Pizzuto, A. [Associazione ENEA-Euratom sulla Fusione C.R.Frascati - 00044-Frascati, RM (Italy); Tati, A. [Associazione Euratom-ENEA sulla Fusione, C.R.Casaccia, Via Anguillarese 301-00123 S. Maria di Galeria, RM (Italy); Visca, E. [Associazione ENEA-Euratom sulla Fusione C.R.Frascati - 00044-Frascati, RM (Italy)

    2011-10-15

    This paper discusses the application of non-destructive testing (NDT) by ultrasonic technique for the control of the joining interfaces of the ITER divertor vertical target plasma facing units. The defect detection capability has to be proved for both metal to metal and metal to carbon/carbon fibre composite (CFC) joints because these two types of joints have to be realized for the manufacturing of the high heat flux units. In this paper the UT results coming from the investigation performed during the manufacturing, but also after the thermal fatigue testing (up to 20 MW/m{sup 2}) of six mock-ups manufactured using the Hot Radial Pressure technology (HRP) in ENEA labs are presented and compared with the evidences from the final destructive examination. Regarding the Cu/CFC joint, the effectiveness of the ultrasonic test has been deeply studied due to the high acoustic attenuation of CFC to ultrasonic waves. To investigate the possibility to use the ultrasonic technique for this type of joint, an 'ad hoc' flat Cu/CFC joint sample, that reproduces the actual annular joint interfaces, was manufactured. This flat sample has the advantage of being easily tested by probes with different geometry and frequency. UT results are compared with X-ray and eddy current testing of the same sample.

  5. Partial Safety Analysis for a Reduced Uranium Enrichment Core for the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Primm, Trent [ORNL; Gehin, Jess C [ORNL

    2009-04-01

    A computational model of the reactor core of the High Flux Isotope Rector (HFIR) was developed in order to analyze non-destructive accidents caused by transients during reactor operation. The reactor model was built for the latest version of the nuclear analysis software package called Program for the Analysis of Reactor Transients (PARET). Analyses performed with the model constructed were compared with previous data obtained with other tools in order to benchmark the code. Finally, the model was used to analyze the behavior of the reactor under transients using a different nuclear fuel with lower enrichment of uranium (LEU) than the fuel currently used, which has a high enrichment of uranium (HEU). The study shows that the presence of fertile isotopes in LEU fuel, which increases the neutron resonance absorption, reduces the impact of transients on the fuel and enhances the negative reactivity feedback, thus, within the limitations of this study, making LEU fuel appear to be a safe alternative fuel for the reactor core.

  6. Non-destructive methods for the defect detection in the ITER high heat flux components

    International Nuclear Information System (INIS)

    This paper discusses the application of non-destructive testing (NDT) by ultrasonic technique for the control of the joining interfaces of the ITER divertor vertical target plasma facing units. The defect detection capability has to be proved for both metal to metal and metal to carbon/carbon fibre composite (CFC) joints because these two types of joints have to be realized for the manufacturing of the high heat flux units. In this paper the UT results coming from the investigation performed during the manufacturing, but also after the thermal fatigue testing (up to 20 MW/m2) of six mock-ups manufactured using the Hot Radial Pressure technology (HRP) in ENEA labs are presented and compared with the evidences from the final destructive examination. Regarding the Cu/CFC joint, the effectiveness of the ultrasonic test has been deeply studied due to the high acoustic attenuation of CFC to ultrasonic waves. To investigate the possibility to use the ultrasonic technique for this type of joint, an 'ad hoc' flat Cu/CFC joint sample, that reproduces the actual annular joint interfaces, was manufactured. This flat sample has the advantage of being easily tested by probes with different geometry and frequency. UT results are compared with X-ray and eddy current testing of the same sample.

  7. Changes of composition and microstructure of joint interface of tungsten coated carbon by high heat flux

    International Nuclear Information System (INIS)

    Tungsten coatings of 0.5 and 1 mm thickness were successfully deposited by the vacuum plasma spraying (VPS) technique on carbon/carbon fiber composite (CFC), CX-2002U and isotropic fine grained graphite, IG-430U. High heat flux experiments by irradiation of electron beam with uniform profile were performed on the coated samples in order to prove the suitability and load limit of such coating materials. The cross-sectional composition and structure of the interface of VPS-W and carbon material samples were investigated. Compositional analyses showed that the Re/W multi-layer acts as diffusion barrier for carbon and suppresses tungsten carbide formation in the VPS-W layer at high temperature about 1300 deg. C. Microstructure of the joint interface of the sample changed in the case of a peak temperature of about 2800 deg. C. The multi-layer structure completely disappeared and compositional distribution was almost uniform in the interface of the sample after melting and resolidification. The diffusion barrier for carbon is not expected to act in this stage

  8. Phosphoglycerate Mutase Is a Highly Efficient Enzyme without Flux Control in Lactococcus lactis

    DEFF Research Database (Denmark)

    Solem, Christian; Petranovic, D.; Købmann, Brian;

    2010-01-01

    The glycolytic enzyme phosphoglycerate mutase (PGM), which catalyzes the conversion of 3-phosphoglycerate to 2-phosphoglycerate, was examined in Lactococcus lactis with respect to its function, kinetics and glycolytic flux control. A library of strains with PGM activities ranging between 15-465% of....... lactis PGM was dependent on 2,3-bisphosphoglyceric acid for activity, which showed that the enzyme is of the dPGM type in accordance with its predicted homology to dPGM enzymes from other organisms. In conclusion, PGM from L. lactis is a highly efficient catalyst, which partially explains why this enzyme...... at highly reduced PGM activities. At the wild-type level PGM operated very far from V-max. Consequently, in a strain with only 15% PGM activity, the catalytic rate of PGM was almost six times higher than in the wildtype. K-m of PGM for 3-phosphoglycerate was 1.0 m M and k(cat) was 3,200 s(-1). The L...

  9. Status of FeCrAl ODS Irradiations in the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD)

    2016-08-19

    FeCrAl oxide-dispersion strengthened (ODS) alloys are an attractive sub-set alloy class of the more global FeCrAl material class for nuclear applications due to their high temperature steam oxidation resistance and hypothesized enhanced radiation tolerance. A need currently exists to determine the radiation tolerance of these newly developed alloys. To address this need, a preliminary study was conducted using the High Flux Isotope Reactor (HFIR) to irradiate an early generation FeCrAl ODS alloy, 125YF. Preliminary post-irradiation examination (PIE) on these irradiated specimens have shown good radiation tolerance at elevated temperatures (≥330°C) but possible radiation-induced hardening and embrittlement at irradiations of 200°C to a damage level of 1.9 displacement per atom (dpa). Building on this experience, a new series of irradiations are currently being conceptualized. This irradiation series called the FCAD irradiation program will irradiate the latest generation FeCrAl ODS and FeCr ODS alloys to significantly higher doses. These experiments will provide the necessary information to determine the mechanical performance of irradiated FeCrAl ODS alloys at light water reactor and fast reactor conditions.

  10. External event probabilistic risk assessment for the High Flux Isotope Reactor (HFIR)

    International Nuclear Information System (INIS)

    The High Flux Isotope Reactor (HFIR) is a high performance isotope production and research reactor which has been in operation at Oak Ridge National Laboratory (ORNL) since 1965. In late 1986 the reactor was shut down as a result of discovery of unexpected neutron embrittlement of the reactor vessel. In January of 1988 a level 1 Probabilistic Risk Assessment (PRA) (excluding external events) was published as part of the response to the many reviews that followed the shutdown and for use by ORNL to prioritize action items intended to upgrade the safety of the reactor. A conservative estimate of the core damage frequency initiated by internal events for HFIR was 3.11 x 10-4. In June 1989 a draft external events initiated PRA was published. The dominant contributions from external events came from seismic, wind, and fires. The overall external event contribution to core damage frequency is about 50% of the internal event initiated contribution and is dominated by seismic events

  11. High Performance of Space Vector Modulation Direct Torque Control SVM-DTC Based on Amplitude Voltage and Stator Flux Angle

    Directory of Open Access Journals (Sweden)

    Hassan Farhan Rashag

    2013-04-01

    Full Text Available Various aspects related to controlling induction motor are investigated. Direct torque control is an original high performance control strategy in the field of AC drive. In this proposed method, the control system is based on Space Vector Modulation (SVM, amplitude of voltage in direct- quadrature reference frame (d-q reference and angle of stator flux. Amplitude of stator voltage is controlled by PI torque and PI flux controller. The stator flux angle is adjusted by rotor angular frequency and slip angular frequency. Then, the reference torque and the estimated torque is applied to the input of PI torque controller and the control quadrature axis voltage is determined. The control d-axis voltage is determined from the flux calculator. These q and d axis voltage are converted into amplitude voltage. By applying polar to Cartesian on amplitude voltage and stator flux angle, direct voltage and quadratures voltage are generated. The reference stator voltages in d-q are calculated based on forcing the stator voltage error to zero at next sampling period. By applying inverse park transformation on d-q voltages, the stator voltages in &alpha and &beta frame are generated and apply to SVM. From the output of SVM, the motor control signal is generated and the speed of the induction motor regulated toward the rated speed. The simulation Results have demonstrated exceptional performance in steady and transient states and shows that decrease of torque and flux ripples is achieved in a complete speed range.

  12. High Heat Flux Testing of a Helium-Cooled Tungsten Tube with Porous Foam

    International Nuclear Information System (INIS)

    Utramet, Inc. fabricated refractory heat exchanger tubes of chemical vapor deposited (CVD) tungsten with an integrally bonded core of open-cell CVD tungsten foam. The 10 pores-per-inch, 20% dense foam is very open (80% porous) with a structure of joined ligaments that combines a relatively low resistance to flow and a large area for heat transfer. Sandia National Laboratories tested the helium-cooled tungsten foam tubes in Sandia's Electron Beam Test Stand (EBTS), a 30 kW electron beam high heat flux facility that includes a closed helium cooling loop. The specimens were 12.7 mm ID x 16.2 mm OD W tubes with W foam centered along 38 mm of the axial length. CVD niobium coating of the ends of the tubes permitted the use of compression fittings to join the specimens to the piping of the helium loop. The fabrication and testing of the specimens were funded through a Phase I grant by the US Department of Energy's Small Business Innovation Research Program. We also tested an open CVD tungsten tube without the porous foam for comparison. Tests were performed in EBTS at progressively higher heat loads. With the foam sample, the maximum absorbed heat load was ∼ 22 MW/m2 with helium at 4 MPa, flowing at 27 g/s and with inlet and outlet temperatures of 40 oC and 91 oC and a pressure drop of ∼ 92 kPa. The helium removed over 7100 W steady state from the part at the highest heat flux. The part failed and fragmented during the cool down after exposure to this heat load. While the fragmentation of the sample indicates that development of more robust W or Mo alloy components will ultimately be required, which are feasible via CVD and part of proposed Phase II work, the very high heat load obtained in these tests is an impressive result for the potential of helium-cooled refractory systems for plasma facing components in fusion devices. The paper reports details of the test, including the surface temperature distributions indicated by an infrared camera and pyrometers, the

  13. BROOKHAVEN NATIONAL LABORATORY SITE ENVIRONMENTAL REPORT FOR CALENDAR YEAR 1994.

    Energy Technology Data Exchange (ETDEWEB)

    NAIDU,J.R.; ROYCE,B.A.

    1995-05-01

    This report documents the results of the Environmental Monitoring Program at Brookhaven National Laboratory and presents summary information about environmental compliance for 1994. To evaluate the effect of Brookhaven National Laboratory's operations on the local environment, measurements of direct radiation, and a variety of radionuclides and chemical compounds in ambient air, soil, sewage effluent, surface water, groundwater, fauna and vegetation were made at the Brookhaven National Laboratory site and at sites adjacent to the Laboratory. Brookhaven National Laboratory's compliance with all applicable guides, standards, and limits for radiological and nonradiological emissions and effluents to the environment were evaluated. Among the permitted facilities, two instances of pH exceedances were observed at recharge basins, possibly related to rain-water run-off to these recharge basins. Also, the discharge from the Sewage Treatment Plant to the Peconic River exceeded. on ten occasions, one each for fecal coliform and 5-day Biochemical Oxygen Demand (avg.) and eight for ammonia nitrogen. The ammonia and Biochemical Oxygen Demand exceedances were attributed to the cold winter and the routine cultivation of the sand filter beds which resulted in the hydraulic overloading of the filter beds and the possible destruction of nitrifying bacteria. The on-set of warm weather and increased aeration of the filter beds via cultivation helped to alleviate this condition. The discharge of fecal coliform may also be linked to this occurrence, in that the increase in fecal coliform coincided with the increased cultivation of the sand filter beds. The environmental monitoring data has identified site-specific contamination of groundwater and soil. These areas are subject to Remedial Investigation/Feasibility Studies under the Inter Agency Agreement. Except for the above, the environmental monitoring data has continued to demonstrate that compliance was achieved with

  14. High heat flux components in fusion devices: from nowadays experience in Tore Supra towards the ITER challenge

    International Nuclear Information System (INIS)

    A pioneering activity has been developed by CEA and the European industry in the field of actively cooled high heat flux plasma facing components in Tore Supra operation, which is today culminating with the routine operation of an actively cooled toroidal pumped limiter (TPL) capable to sustain up to 10 MW.m-2 of nominal convected heat flux. This success is the result of a long lead development and industrialization program (about 10 years) marked out with a number of technical and managerial challenges that were taken up and has allowed us to build up an unique experience feedback database. This is illustrated in this paper with the specific example of the development of high heat flux CFC-on-CuCrZr (carbon-carbon fibre composite on hardened copper alloy CuCrZr) component from design phase to tokamak operation. (authors)

  15. Blister bursting and deuterium bursting release from tungsten exposed to high fluences of high flux and low energy deuterium plasma

    International Nuclear Information System (INIS)

    Deuterium retention and blistering in the near-surface region of tungsten exposed to high fluences (up to 1027 D m-2) of high flux (1022D+ m-2 s-1) and low energy (38 eV) deuterium plasma were examined with scanning electron microscopy, focused ion beam and thermal desorption spectroscopy (TDS). Two kinds of blisters appeared at the recrystallized tungsten exposed to the plasma at 520 K. One is the large blisters with sizes of a few tens of micrometres and varying ratios of height against width (up to 0.6), and the other is the small blisters with sizes of less than a few micrometres and a large ratio of height against diameter (about 0.7). A peculiar phenomenon of blister bursting with a tail, or partially opened or fully opened lid was found on some grains after plasma exposure or TDS experiment. In addition, bursting release of deuterium with sudden peaks was observed in the TDS curve below 700 K at a heating rate of 0.5 K s-1. A new model named 'step-cascade model' was proposed to explain the blister bursting. Furthermore, the origin of deuterium retention and blistering as well as future work on high-Z materials were discussed

  16. Investigating the suitability of GaAs:Cr material for high flux X-ray imaging

    Science.gov (United States)

    Veale, M. C.; Bell, S. J.; Duarte, D. D.; French, M. J.; Hart, M.; Schneider, A.; Seller, P.; Wilson, M. D.; Kachkanov, V.; Lozinskaya, A. D.; Novikov, V. A.; Tolbanov, O. P.; Tyazhev, A.; Zarubin, A. N.

    2014-12-01

    Semi-insulating wafers of GaAs material with a thickness of 500μm have been compensated with chromium by Tomsk State University. Initial measurements have shown the material to have high resistivity (3 × 109Ωcm) and tests with pixel detectors on a 250 μm pitch produced uniform spectroscopic performance across an 80 × 80 pixel array. At present, there is a lack of detectors that are capable of operating at high X-ray fluxes (> 108 photons s-1 mm-2) in the energy range 5-50 keV. Under these conditions, the poor stopping power of silicon, as well as issues with radiation hardness, severely degrade the performance of traditional detectors. While high-Z materials such as CdTe and CdZnTe may have much greater stopping power, the formation of space charge within these detectors degrades detector performance. Initial measurements made with GaAs:Cr detectors suggest that many of its material properties make it suitable for these challenging conditions. In this paper the radiation hardness of the GaAs:Cr material has been measured on the B16 beam line at the Diamond Light Source synchrotron. Small pixel detectors were bonded to the STFC Hexitec ASIC and were irradiated with 3 × 108 photons s-1 mm-2 monochromatic 12 keV X-rays up to a maximum dose of 0.6 MGy. Measurements of the spectroscopic performance before and after irradiation have been used to assess the extent of the radiation damage.

  17. High rates of energy expenditure and water flux in free-ranging Point Reyes mountain beavers Aplodontia rufa phaea

    Science.gov (United States)

    Crocker, D.E.; Kofahl, N.; Fellers, G.D.; Gates, N.B.; Houser, D.S.

    2007-01-01

    We measured water flux and energy expenditure in free-ranging Point Reyes mountain beavers Aplodontia rufa phaea by using the doubly labeled water method. Previous laboratory investigations have suggested weak urinary concentrating ability, high rates of water flux, and low basal metabolic rates in this species. However, free-ranging measurements from hygric mammals are rare, and it is not known how these features interact in the environment. Rates of water flux (210 ?? 32 mL d-1) and field metabolic rates (1,488 ?? 486 kJ d-1) were 159% and 265%, respectively, of values predicted by allometric equations for similar-sized herbivores. Mountain beavers can likely meet their water needs through metabolic water production and preformed water in food and thus remain in water balance without access to free water. Arginine-vasopressin levels were strongly correlated with rates of water flux and plasma urea : creatinine ratios, suggesting an important role for this hormone in regulating urinary water loss in mountain beavers. High field metabolic rates may result from cool burrow temperatures that are well below lower critical temperatures measured in previous laboratory studies and suggest that thermoregulation costs may strongly influence field energetics and water flux in semifossorial mammals. ?? 2007 by The University of Chicago. All rights reserved.

  18. Radiation-induced swelling and softening in magnesium aluminate spinel irradiated with high-flux Cu{sup -} ions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.G. E-mail: cglee@clear.tokai.jaeri.go.jp; Ohmura, T.; Takeda, Y.; Matsuoka, S.; Kishimoto, N

    2004-03-15

    Magnesium aluminate spinel of single crystal was irradiated with 60 keV Cu{sup -} at a flux up to 6.2 x 10{sup 18} ions/m{sup 2} s, to a total fluence of 3 x 10{sup 20} ions/m{sup 2}, in order to study changes in hardness and step-height swelling by high-flux implantation. Hardness determined by nano-indentation measurements steeply decreased with implantation. There is a strong negative correlation between flux dependences of the hardness and the step-height swelling: the former decreases as the latter increases. The Rutherford backscattering spectrometry (RBS)/channeling measurements showed that the spinel is not completely amorphized over the flux range in this study, and the radiation-induced softening observed is not due to amorphization. Results of optical absorbance suggested that radiation-induced point defects and their clusters on the anion sublattices of the spinel played an important role in the radiation-induced swelling under high-flux ion implantation.

  19. Radiation-induced swelling and softening in magnesium aluminate spinel irradiated with high-flux Cu- ions

    International Nuclear Information System (INIS)

    Magnesium aluminate spinel of single crystal was irradiated with 60 keV Cu- at a flux up to 6.2 x 1018 ions/m2 s, to a total fluence of 3 x 1020 ions/m2, in order to study changes in hardness and step-height swelling by high-flux implantation. Hardness determined by nano-indentation measurements steeply decreased with implantation. There is a strong negative correlation between flux dependences of the hardness and the step-height swelling: the former decreases as the latter increases. The Rutherford backscattering spectrometry (RBS)/channeling measurements showed that the spinel is not completely amorphized over the flux range in this study, and the radiation-induced softening observed is not due to amorphization. Results of optical absorbance suggested that radiation-induced point defects and their clusters on the anion sublattices of the spinel played an important role in the radiation-induced swelling under high-flux ion implantation

  20. Radiation-induced swelling and softening in magnesium aluminate spinel irradiated with high-flux Cu - ions

    Science.gov (United States)

    Lee, C. G.; Ohmura, T.; Takeda, Y.; Matsuoka, S.; Kishimoto, N.

    2004-03-01

    Magnesium aluminate spinel of single crystal was irradiated with 60 keV Cu - at a flux up to 6.2 × 10 18 ions/m 2 s, to a total fluence of 3 × 10 20 ions/m 2, in order to study changes in hardness and step-height swelling by high-flux implantation. Hardness determined by nano-indentation measurements steeply decreased with implantation. There is a strong negative correlation between flux dependences of the hardness and the step-height swelling: the former decreases as the latter increases. The Rutherford backscattering spectrometry (RBS)/channeling measurements showed that the spinel is not completely amorphized over the flux range in this study, and the radiation-induced softening observed is not due to amorphization. Results of optical absorbance suggested that radiation-induced point defects and their clusters on the anion sublattices of the spinel played an important role in the radiation-induced swelling under high-flux ion implantation.

  1. Tritium trapping in silicon carbide in contact with solid breeder under high flux isotope reactor irradiation

    International Nuclear Information System (INIS)

    The trapping of tritium in silicon carbide (SiC) injected from ceramic breeding materials was examined via tritium measurements using imaging plate (IP) techniques. Monolithic SiC in contact with ternary lithium oxide (lithium titanate and lithium aluminate) as a ceramic breeder was irradiated in the High Flux Isotope Reactor (HFIR) in Oak Ridge, Tennessee, USA. The distribution of photo-stimulated luminescence (PSL) of tritium in SiC was successfully obtained, which separated the contribution of 14C β-rays to the PSL. The tritium incident from ceramic breeders was retained in the vicinity of the SiC surface even after irradiation at 1073 K over the duration of ∼3000 h, while trapping of tritium was not observed in the bulk region. The PSL intensity near the SiC surface in contact with lithium titanate was higher than that obtained with lithium aluminate. The amount of the incident tritium and/or the formation of a Li2SiO3 phase on SiC due to the reaction with lithium aluminate under irradiation likely were responsible for this observation

  2. High-flux cold rubidium atomic beam for strongly-coupled cavity QED

    International Nuclear Information System (INIS)

    This paper presents a setup capable of producing a high-flux continuous beam of cold rubidium atoms for cavity quantum electrodynamics experiments in the region of strong coupling. A 2D+ magneto-optical trap (MOT), loaded with rubidium getters in a dry-film-coated vapor cell, fed a secondary moving-molasses MOT (MM-MOT) at a rate greater than 2 x 1010 atoms/s. The MM-MOT provided a continuous beam with a tunable velocity. This beam was then directed through the waist of a cavity with a length of 280 μm, resulting in a vacuum Rabi splitting of more than ±10 MHz. The presence of a sufficient number of atoms in the cavity mode also enabled splitting in the polarization perpendicular to the input. The cavity was in the strong coupling region, with an atom-photon dipole coupling coefficient g of 7 MHz, a cavity mode decay rate κ of 3 MHz, and a spontaneous emission decay rate γ of 6 MHz.

  3. Biological implications of high-energy cosmic ray induced muon flux in the extragalactic shock model

    CERN Document Server

    Atri, Dimitra

    2011-01-01

    A ~ 62 My periodicity in fossil biodiversity has been observed in independent studies of paleobiology databases going back 542 My. The period and phase of this biodiversity cycle coincides with the motion of our solar system in the galactic disk that oscillates perpendicular to the galactic plane with an amplitude of about 70 parsecs and a period of 63.6 My. Our Galaxy is falling toward the Virgo cluster due to its gravitational pull, forming a galactic shock at the north end of our galaxy due to this motion, capable of accelerating particles and exposing our galaxy's northern side to a higher flux of cosmic rays. These high-energy particles strike the Earth's atmosphere initiating extensive air showers, ionizing the atmosphere by producing charged secondary particles. Secondary particles such as muons produced as a result of nuclear interactions are able to reach the ground, enhancing the biological radiation dose, causing DNA damage and increasing mutation rates, which can have serious biological implicatio...

  4. Proposed Fuel Pin Irradiation Facilities for the High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    The Global Nuclear Energy Partnership (GNEP) is proposing to develop a sodium-cooled fast-spectrum reactor (SFR) to transmute and consume actinides from spent nuclear fuel. The proposed fuels include metal and oxide mixed actinides (U-Np-Pu-Am-Cm) as well as target concepts with perhaps only Am-Cm. The High Flux Isotope Reactor was built for the purpose of transmuting plutonium to various higher actinides including Am, Cm, and Cf. Since a fast-spectrum irradiation facility does not exist in the United States, HFIR can fulfill a first step in the GNEP mission; that being to establish a near-term capability to irradiate materials in a fast neutron spectrum in addition to efforts to gain access to international facilities through partnering arrangements. Modifications to the HFIR central target region to accomplish this goal are described. A second on-going project for HFIR is to design capsules and installation tools and procedures to irradiate short rods of innovative nuclear fuel types and cladding materials under prototypic LWR operating conditions at an accelerated rate relative to expected reactor performance. This second proposal would be for a facility representative of thermal reactor conditions rather than the GNEP concept. In order to maintain power densities within the fuel at levels normally seen by LWR reactors, an entirely new experiment and test capsule design will be needed than has been available in the past

  5. Proposed fuel pin irradiation facilities for the high flux isotope reactor

    International Nuclear Information System (INIS)

    The Global Nuclear Energy Partnership (GNEP) is proposing to develop a sodium-cooled fast-spectrum reactor (SFR) to transmute and consume actinides from spent nuclear fuel. The proposed fuels include metal and oxide forms mixed actinides (U-Np-Pu-Am-Cm) as well as target concepts with perhaps both Am-Cm. The High Flux Isotope Reactor (HFIR) was built for the purpose of transmuting plutonium to various higher actinides including Am, Cm, and Cf Since a fast-spectrum irradiation facility does not exist in the United States, HFIR can fulfill a first step in the GNEP- mission that being to establish a near-term domestic capability to irradiate materials in a fast neutron spectrum. Modifications to the HFIR central target region to accomplish this goal are described. A second ongoing project for HFIR is to design capsules and installation tools and procedures to irradiate short rods of innovative nuclear fuel types and cladding materials under prototypic light water reactor (LWR) operating conditions at an accelerated rate relative to expected reactor performance. This second proposal would be for a facility representative of thermal reactor conditions rather than the GNEP concept. In order to maintain power densities within the fuel at levels normally seen by LWR reactors, an entirely new experiment and test capsule design will be needed. (authors)

  6. Deuterium retention and surface modifications of nanocrystalline tungsten films exposed to high-flux plasma

    International Nuclear Information System (INIS)

    Highlights: • The films withstand the intense plasma exposure maintaining overall integrity. • An increase of deuterium retention was observed with decreasing tungsten density. • Formation of micrometer-sized blisters as well as structures on the nanometer scale depending on the layer type. - Abstract: Deuterium retention studies are presented for nanostructured tungsten films exposed to high-flux deuterium plasmas. Thin tungsten films of ∼1 μm thickness were deposited with pulsed laser deposition (PLD) on bulk tungsten. Surface modifications were studied with scanning electron microscopy and deuterium retention with thermal desorption spectroscopy. Three types of PLD films with different densities and crystallinity were studied after exposure to deuterium plasmas. The surface temperature ranged from about 460 K at the periphery to about 520 K in the centre of the targets. The films withstand the intense plasma exposure well and maintain their overall integrity. An increase of deuterium retention is observed with decreasing tungsten density and crystallite size. We found that the filling of these thin films with deuterium is significantly faster than for pre-damaged polycrystalline tungsten. We observed formation of micrometer-sized blisters as well as structures on the nanometer scale, both depending on the layer type

  7. Water flow characteristics of Baumkuchen type fuel elements for Kyoto University high neutron flux reactor

    International Nuclear Information System (INIS)

    The Kyoto University high neutron flux reactor is a light water-moderated and cooled, divided core type reactor with heavy water reflector. In the core, six inside fuel elements and twelve outside fuel elements are arranged in double ring form, and two cylindrical, divided cores are placed at 15 cm distance. The flow rate distribution and pressure loss in the fuel elements constitute the base of the thermo-hydraulic design of the core, therefore the model fuel elements of full size were made, and the water flow experiment was carried out to examine their characteristics. It was found that the flow velocity in channels was strongly affected by the accuracy of channel gaps. The calculation of pressure loss in fuel elements, the experiments on inside fuel elements and outside fuel elements, and the results of experiments such as the calibration of the cooling channels in outside fuel elements, the relation between total flow rate and pressure loss, and the characteristics of flow at the time of reverse flow are reported. The general characteristics of flow in fuel elements were in good agreement with the prediction. In the pressure loss in fuel elements, the friction between fuel plates and the resistance of nozzles were the controlling factors under the rated operating conditions of the HFR. (Kako, I.)

  8. High heat flux testing of CFC composites for the tokamak physics experiment

    Science.gov (United States)

    Valentine, P. G.; Nygren, R. E.; Burns, R. W.; Rocket, P. D.; Colleraine, A. P.; Lederich, R. J.; Bradley, J. T.

    1996-10-01

    High heat flux (HHF) testing of carbon fiber reinforced carbon composites (CFC's) was conducted under the General Atomics program to develop plasma-facing components (PFC's) for Princeton Plasma Physics Laboratory's tokamak physics experiment (TPX). As part of the process of selecting TPX CFC materials, a series of HHF tests were conducted with the 30 kW electron beam test system (EBTS) facility at Sandia National Laboratories, and with the plasma disruption simulator I (PLADIS-I) facility at the University of New Mexico. The purpose of the tests was to make assessments of the thermal performance and erosion behavior of CFC materials. Tests were conducted with 42 different CFC materials. In general, the CFC materials withstood the rapid thermal pulse environments without fracturing, delaminating, or degrading in a non-uniform manner; significant differences in thermal performance, erosion behavior, vapor evolution, etc. were observed and preliminary findings are presented below. The CFC's exposed to the hydrogen plasma pulses in PLADIS-I exhibited greater erosion rates than the CFC materials exposed to the electron-beam pulses in EBTS. The results obtained support the continued consideration of a variety of CFC composites for TPX PFC components.

  9. High-flux cold rubidium atomic beam for strongly-coupled cavity QED

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Basudev [Indian Institute of Science Education and Research, Kolkata (India); University of Maryland, MD (United States); Scholten, Michael [University of Maryland, MD (United States)

    2012-08-15

    This paper presents a setup capable of producing a high-flux continuous beam of cold rubidium atoms for cavity quantum electrodynamics experiments in the region of strong coupling. A 2D{sup +} magneto-optical trap (MOT), loaded with rubidium getters in a dry-film-coated vapor cell, fed a secondary moving-molasses MOT (MM-MOT) at a rate greater than 2 x 10{sup 10} atoms/s. The MM-MOT provided a continuous beam with a tunable velocity. This beam was then directed through the waist of a cavity with a length of 280 μm, resulting in a vacuum Rabi splitting of more than ±10 MHz. The presence of a sufficient number of atoms in the cavity mode also enabled splitting in the polarization perpendicular to the input. The cavity was in the strong coupling region, with an atom-photon dipole coupling coefficient g of 7 MHz, a cavity mode decay rate κ of 3 MHz, and a spontaneous emission decay rate γ of 6 MHz.

  10. The method of life extension for the High Flux Isotope Reactor vessel

    International Nuclear Information System (INIS)

    The state of the vessel steel embrittlement as a result of neutron irradiation can be measured by its increase in the nil ductility temperature (NDT). This temperature is sometimes referred to as the brittle-ductile transition temperature (DBT) for fracture. The life extension of the High Flux Isotope Reactor (HFIR) vessel is calculated by using the method of fracture mechanics. A hydrostatic pressure test (hydrotest) is performed in order to determine a safe vessel static pressure. It is then followed by using fracture mechanics to project the reactor life from the safe hydrostatic pressure. The life extension calculation provides the following information on the remaining life of the reactor as a function of the nil ductility temperature increase: (1) the probability of vessel fracture due to hydrotest vs vessel life at several hydrotest pressures, (2) the hydrotest time interval vs the uncertainty of the nil ductility temperature increase rate, and (3) the hydrotest pressure vs the uncertainty of the nil ductility temperature increase rate. It is understood that the use of a complete range of uncertainties of the nil ductility temperature increase is equivalent to the entire range of radiation damage that can be experienced by the vessel steel. From the numerical values for the probabilities of the vessel fracture as a result of hydrotest, it is estimated that the reactor vessel life can be extended up to 50 EFPY (100 MW) with the minimum vessel operating temperature equal to 85 F

  11. Total quality management for addressing suspect parts at the Oak Ridge High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    Martin Marietta Energy System (MMES) Research Reactors Division (RRD), operator of the High Flux Isotope Reactor (HFIR) recently embarked on an aggressive Program to address the issue of suspect Parts and to enhance their procurement process. Through the application of TQM process improvement, RRD has already achieved improved efficiency in specifying, procuring, and accepting replacement items for its largest research reactor. These process improvements have significantly decreased the risk of installing suspect parts in the HFIR safety systems. To date, a systematic plan has been implemented, which includes the following elements: Process assessment and procedure review; Procedural enhancements; On-site training and technology transfer; Enhanced receiving inspections; Performance supplier evaluations and source verifications integrated processes for utilizing commercial grade products in nuclear safety-related applications. This paper will describe the above elements, how a partnership between MMES and Gilbert/Commonwealth facilitated the execution of the plan, and how process enhancements were applied. We will also present measures for improved efficiency and productivity, that MMES intends to continually address with Quality Action Teams

  12. Postirradiation properties of the 6061-T6 aluminum High Flux Isotope Reactor hydraulic tube

    International Nuclear Information System (INIS)

    A tube of 6061 aluminum alloy in a T6 temper, precipitation-hardened with Mg2Si, was examined after irradiation in the core of the High Flux Isotope Reactor to fluences up to 1.3 x 1023 neutrons (n)/cm2 (0.1 MeV) and 3.1 x 1023 n/cm2 (thermal) in contact with the cooling water at a temperature of about 550C. The alloy displayed up to 2.5 percent swelling due mainly to a precipitate of transmutation-produced silicon of which more than 6 weight percent was formed. Some cavities were also observed. Tension tests in the temperature range 55 to 2000C showed radiation-induced increases in yield stresses and ultimate stresses of 50 to 80 percent; elongation was reduced from the range 10 to 15 percent to about 5 percent at 550C and to about 3 percent at test temperatures above 1000C. The fracture mode was changed from transgranular tearing around inclusions to a mixture of transgranular tearing and ductile intergranular separation. These changes are attributed primarily to the radiation-induced silicon precipitate. A rim of intergranular cracks formed at the originally oxidized surfaces of the tube duringtension testing and became deeper with increasing neutron irradiation and increasing temperature

  13. Postirradiation properties of the 6061-T6 aluminum high flux isotope reactor hydraulic tube

    International Nuclear Information System (INIS)

    A tube of 6061 aluminum alloy in a T6 temper, precipitation-hardened with Mg2Si, was examined after irradiation in the core of the High Flux Isotope Reactor to fluences up to 1.3 x 1023 neutrons (n)/cm2 (0.1 MeV) and 3.1 x 1023 n/cm2 (thermal) in contact with the cooling water at a temperature of about 550C. The alloy displayed up to 2.5 percent swelling due mainly to a precipitate of transmutaion-produced silicon of which more than 6 weight perent was formed. Some cavities were also observed. Tension tests in the temperature range 55 to 2000C showed radiation-induced increases in yield stresses and ultimate stresses of 50 to 80 percent; elongation was reduced from the range 10 to 15 percent to about 5 percent at 55C0 and to about 3 percent at test temperatures above 100C0. The fracture mode was changed from transgranular tearing around inclusions to a mixture of transgranular tearing and ductile intergradular separation. These changes are attributed primarily to the radiation-induced silicon precipitate. A rim of intergranular cracks formed at the originally oxidized surfaces of the tube during tension testing and became deeper with increasing neutron irradiation and increasing temperature

  14. Manufacturing and thermomechanical testing of actively cooled all beryllium high heat flux test pieces

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, N.N.; Sokolov, Yu.A.; Shatalov, G.E. [and others

    1995-09-01

    One of the problems affiliated to ITER high heat flux elements development is a problem of interface of beryllium protection with heat sink routinely made of copper alloys. To get rid of this problem all beryllium elements could be used as heat receivers in places of enhanced thermal loads. In accordance with this objectives four beryllium test pieces of two types have been manufactured in {open_quotes}Institute of Beryllium{close_quotes} for succeeding thermomechanical testing. Two of them were manufactured in accordance with JET team design; they are round {open_quotes}hypervapotron type{close_quotes} test pieces. Another two ones are rectangular test sections with a twisted tape installed inside of the circular channel. Preliminary stress-strain analysis have been performed for both type of the test pieces. Hypervapotrons have been shipped to JET where they were tested on JET test bed. Thermomechanical testing of pieces of the type of {open_quotes}swirl tape inside of tube{close_quotes} have been performed on Kurchatov Institute test bed. Chosen beryllium grade properties, some details of manufacturing, results of preliminary stress-strain analysis and thermomechanical testing of the test pieces {open_quotes}swirl tape inside of tube{close_quotes} type are given in this report.

  15. High density flux of Co nanoparticles produced by a simple gas aggregation apparatus

    International Nuclear Information System (INIS)

    Gas aggregation is a well known method used to produce clusters of different materials with good size control, reduced dispersion, and precise stoichiometry. The cost of these systems is relatively high and they are generally dedicated apparatuses. Furthermore, the usual sample production speed of these systems is not as fast as physical vapor deposition devices posing a problem when thick samples are needed. In this paper we describe the development of a multipurpose gas aggregation system constructed as an adaptation to a magnetron sputtering system. The cost of this adaptation is negligible and its installation and operation are both remarkably simple. The gas flow for flux in the range of 60-130 SCCM (SCCM denotes cubic centimeter per minute at STP) is able to completely collimate all the sputtered material, producing spherical nanoparticles. Co nanoparticles were produced and characterized using electron microscopy techniques and Rutherford back-scattering analysis. The size of the particles is around 10 nm with around 75 nm/min of deposition rate at the center of a Gaussian profile nanoparticle beam.

  16. Deuterium retention and surface modifications of nanocrystalline tungsten films exposed to high-flux plasma

    Energy Technology Data Exchange (ETDEWEB)

    Hoen, M.H.J. ' t [FOM Institute DIFFER (Dutch Institute for Fundamental Energy Research), Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, 3439 MN Nieuwegein (Netherlands); Dellasega, D.; Pezzoli, A.; Passoni, M. [Politecnico di Milano, EURATOM-ENEA-CNR Association, Milano (Italy); Kleyn, A.W., E-mail: A.W.Kleijn@uva.nl [FOM Institute DIFFER (Dutch Institute for Fundamental Energy Research), Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, 3439 MN Nieuwegein (Netherlands); University of Amsterdam, Science Park 904, NL-1098 XH Amsterdam (Netherlands); Center of Interface Dynamics for Sustainability, CDCST, CAEP, Chengdu, Sichuan 610207 (China); Zeijlmans van Emmichoven, P.A. [FOM Institute DIFFER (Dutch Institute for Fundamental Energy Research), Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, 3439 MN Nieuwegein (Netherlands)

    2015-08-15

    Highlights: • The films withstand the intense plasma exposure maintaining overall integrity. • An increase of deuterium retention was observed with decreasing tungsten density. • Formation of micrometer-sized blisters as well as structures on the nanometer scale depending on the layer type. - Abstract: Deuterium retention studies are presented for nanostructured tungsten films exposed to high-flux deuterium plasmas. Thin tungsten films of ∼1 μm thickness were deposited with pulsed laser deposition (PLD) on bulk tungsten. Surface modifications were studied with scanning electron microscopy and deuterium retention with thermal desorption spectroscopy. Three types of PLD films with different densities and crystallinity were studied after exposure to deuterium plasmas. The surface temperature ranged from about 460 K at the periphery to about 520 K in the centre of the targets. The films withstand the intense plasma exposure well and maintain their overall integrity. An increase of deuterium retention is observed with decreasing tungsten density and crystallite size. We found that the filling of these thin films with deuterium is significantly faster than for pre-damaged polycrystalline tungsten. We observed formation of micrometer-sized blisters as well as structures on the nanometer scale, both depending on the layer type.

  17. A Photographic study of subcooled flow boiling burnout at high heat flux and velocity

    Energy Technology Data Exchange (ETDEWEB)

    Celata, G.P.; Mariani, A.; Zummo, G. [ENEA, National Institute of Thermal-Fluid Dynamics, Rome (Italy); Cumo, M. [University of Rome (Italy); Gallo, D. [University of Palermo (Italy). Department of Nuclear Engineering

    2007-01-15

    The present paper reports the results of a visualization study of the burnout in subcooled flow boiling of water, with square cross section annular geometry (formed by a central heater rod contained in a duct characterized by a square cross section). The coolant velocity is in the range 3-10m/s. High speed movies of flow pattern in subcooled flow boiling of water from the onset of nucleate boiling up to physical burnout of the heater are recorded. From video images (single frames taken with a stroboscope light and an exposure time of 1{mu}s), the following general behaviour of vapour bubbles was observed: when the rate of bubble generation is increasing, with bubbles growing in the superheated layer close to the heating wall, their coalescence produces a type of elongated bubble called vapour blanket. One of the main features of the vapour blanket is that it is rooted to the nucleation site on the heated surface. Bubble dimensions are given as a function of thermal-hydraulic tested conditions for the whole range of velocity until the burnout region. A qualitative analysis of the behaviour of four stainless steel heater wires with different macroscopic surface finishes is also presented, showing the importance of this parameter on the dynamics of the bubbles and on the critical heat flux. (author)

  18. STATUS OF HIGH FLUX ISOTOPE REACTOR IRRADIATION OF SILICON CARBIDE/SILICON CARBIDE JOINTS

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, Yutai [ORNL; Koyanagi, Takaaki [ORNL; Kiggans, Jim [ORNL; Cetiner, Nesrin [ORNL; McDuffee, Joel [ORNL

    2014-09-01

    Development of silicon carbide (SiC) joints that retain adequate structural and functional properties in the anticipated service conditions is a critical milestone toward establishment of advanced SiC composite technology for the accident-tolerant light water reactor (LWR) fuels and core structures. Neutron irradiation is among the most critical factors that define the harsh service condition of LWR fuel during the normal operation. The overarching goal of the present joining and irradiation studies is to establish technologies for joining SiC-based materials for use as the LWR fuel cladding. The purpose of this work is to fabricate SiC joint specimens, characterize those joints in an unirradiated condition, and prepare rabbit capsules for neutron irradiation study on the fabricated specimens in the High Flux Isotope Reactor (HFIR). Torsional shear test specimens of chemically vapor-deposited SiC were prepared by seven different joining methods either at Oak Ridge National Laboratory or by industrial partners. The joint test specimens were characterized for shear strength and microstructures in an unirradiated condition. Rabbit irradiation capsules were designed and fabricated for neutron irradiation of these joint specimens at an LWR-relevant temperature. These rabbit capsules, already started irradiation in HFIR, are scheduled to complete irradiation to an LWR-relevant dose level in early 2015.

  19. A U.S. high-flux neutron facility for fusion materials development

    Energy Technology Data Exchange (ETDEWEB)

    Rei, Donald J [Los Alamos National Laboratory

    2010-01-01

    Materials for a fusion reactor first wall and blanket structure must be able to reliably function in an extreme environment that includes 10-15 MW-year/m{sup 2} neutron and heat fluences. The various materials and structural challenges are as difficult and important as achieving a burning plasma. Overcoming radiation damage degradation is the rate-controlling step in fusion materials development. Recent advances with oxide dispersion strengthened ferritic steels show promise in meeting reactor requirements, while multi-timescale atomistic simulations of defect-grain boundary interactions in model copper systems reveal surprising self-annealing phenomenon. While these results are promising, simultaneous evaluation of radiation effects displacement damage ({le} 200 dpa) and in-situ He generation ({le} 2000 appm) at prototypical reactor temperatures and chemical environments is still required. There is currently no experimental facility in the U.S. that can meet these requirements for macroscopic samples. The E.U. and U.S. fusion communities have recently concluded that a fusion-relevant, high-flux neutron source for accelerated characterization of the effects of radiation damage to materials is a top priority for the next decade. Data from this source will be needed to validate designs for the multi-$B next-generation fusion facilities such as the CTF, ETF, and DEMO, that are envisioned to follow ITER and NIF.

  20. Carbon and Water Vapor Fluxes of Dedicated Bioenergy Feedstocks: Switchgrass and High Biomass Sorghum

    Science.gov (United States)

    Wagle, P.; Kakani, V. G.; Huhnke, R.

    2015-12-01

    We compared eddy covariance measurements of carbon and water vapor fluxes from co-located two major dedicated lignocellulosic feedstocks, Switchgrass (Panicum virgatum L.) and high biomass sorghum (Sorghum bicolor L. Moench), in Oklahoma during the 2012 and 2013 growing seasons. Monthly ensemble averaged net ecosystem CO2 exchange (NEE) reached seasonal peak values of 36-37 μmol m-2 s-1 in both ecosystems. Similar magnitudes (weekly average of daily integrated values) of NEE (10-11 g C m-2 d-1), gross primary production (GPP, 19-20 g C m-2 d-1), ecosystem respiration (ER, 10-12 g C m-2 d-1), and evapotranspiration (ET, 6.2-6.7 mm d-1) were observed in both ecosystems. Carbon and water vapor fluxes of both ecosystems had similar response to air temperature (Ta) and vapor pressure deficit (VPD). An optimum Ta was slightly over 30 °C for NEE and approximately 35 °C for ET, and an optimum VPD was approximately 3 kPa for NEE and ET in both ecosystems. The switchgrass field was a larger carbon sink, with a cumulative seasonal carbon uptake of 406-490 g C m-2 compared to 261-330 g C m-2 by the sorghum field. Despite similar water use patterns during the active growing period, seasonal cumulative ET was higher in switchgrass than in sorghum. The ratio of seasonal sums of GPP to ET yielded ecosystem water use efficiency (EWUE) of 9.41-11.32 and 8.98-9.17 g CO2 mm-1 ET in switchgrass and sorghum, respectively. The ratio of seasonal sums of net ecosystem production (NEP) to ET was 2.75-2.81 and 2.06-2.18 g CO2 mm-1 ET in switchgrass and sorghum, respectively. The switchgrass stand was a net carbon sink for four to five months (April/May-August), while sorghum was a net carbon sink only for three months (June-August). Our results imply that the difference in carbon sink strength and water use between two ecosystems was driven mainly by the length of the growing season.

  1. Brookhaven highlights, July 1976-September 1978

    International Nuclear Information System (INIS)

    Some of the most significant research accomplishments during this 27-month period are presented. Although some data are given, this report is primarily descriptive in outlook; detailed information on completed work should be sought from the references cited herein or from the usual sources of physics research information. The report is organized as follows: High-energy Physics (general introduction, physics research, accelerators, ISABELLE); Nuclear and Solid State Physics, and Chemistry; Life Sciences (biology, medicine); Applied Energy Science (energy and the environment, reactor systems and safety, National Nuclear Data Center, nuclear materials safeguards); Support Activities (applied mathematics, instrumentation, reactors, safety and environmental protection); and General and Administrative. 117 figures, 16 tables, 315 references

  2. OPTIMIZATION OF THE EPITHERMAL NEUTRON BEAM FOR BORON NEUTRON CAPTURE THERAPY AT THE BROOKHAVEN MEDICAL RESEARCH REACTOR

    International Nuclear Information System (INIS)

    Clinical trials of Boron Neutron Capture Therapy for patients with malignant brain tumor had been carried out for half a decade, using an epithermal neutron beam at the Brookhaven's Medical Reactor. The decision to permanently close this reactor in 2000 cut short the efforts to implement a new conceptual design to optimize this beam in preparation for use with possible new protocols. Details of the conceptual design to produce a higher intensity, more forward-directed neutron beam with less contamination from gamma rays, fast and thermal neutrons are presented here for their potential applicability to other reactor facilities. Monte Carlo calculations were used to predict the flux and absorbed dose produced by the proposed design. The results were benchmarked by the dose rate and flux measurements taken at the facility then in use

  3. Surface Catalysis and Oxidation on Stagnation Point Heat Flux Measurements in High Enthalpy Arc Jets

    Science.gov (United States)

    Nawaz, Anuscheh; Driver, David M.; Terrazas-Salinas

    2013-01-01

    Heat flux sensors are routinely used in arc jet facilities to determine heat transfer rates from plasma plume. The goal of this study is to assess the impact of surface composition changes on these heat flux sensors. Surface compositions can change due to oxidation and material deposition from the arc jet. Systematic surface analyses of the sensors were conducted before and after exposure to plasma. Currently copper is commonly used as surface material. Other surface materials were studied including nickel, constantan gold, platinum and silicon dioxide. The surfaces were exposed to plasma between 0.3 seconds and 3 seconds. Surface changes due to oxidation as well as copper deposition from the arc jets were observed. Results from changes in measured heat flux as a function of surface catalycity is given, along with a first assessment of enthalpy for these measurements. The use of cupric oxide is recommended for future heat flux measurements, due to its consistent surface composition arc jets.

  4. Divertor Heat Flux Mitigation in High-Performance H-mode Discharges in the National Spherical Torus Experiment.

    Energy Technology Data Exchange (ETDEWEB)

    Soukhanovskii, V A; Maingi, R; Gates, D; Menard, J

    2008-12-31

    Experiments conducted in high-performance 1.0 MA and 1.2 MA 6 MW NBI-heated H-mode discharges with a high magnetic flux expansion radiative divertor in NSTX demonstrate that significant divertor peak heat flux reduction and access to detachment may be facilitated naturally in a highly-shaped spherical torus (ST) configuration. Improved plasma performance with high {beta}{sub t} = 15-25%, a high bootstrap current fraction f{sub BS} = 45-50%, longer plasma pulses, and an H-mode regime with smaller ELMs has been achieved in the strongly-shaped lower single null configuration with elongation {kappa} = 2.2-2.4 and triangularity {delta} = 0.6-0.8. Divertor peak heat fluxes were reduced from 6-12 MW/m{sup 2} to 0.5-2 MW/m{sup 2} in ELMy H-mode discharges using the inherently high magnetic flux expansion f{sub m} = 16-25 and the partial detachment of the outer strike point at several D{sub 2} injection rates. A good core confinement and pedestal characteristics were maintained, while the core carbon concentration and the associated Z{sub eff} were reduced. The partially detached divertor regime was characterized by an increase in divertor radiated power, a reduction of ion flux to the plate, and a large neutral compression ratio. Spectroscopic measurements indicated a formation of a high-density, low temperature region adjacent to the outer strike point, where substantial increases in the volume recombination rate and CII, CIII emission rates was measured.

  5. High speed operation design considerations for fractional slot axial flux PMSM

    OpenAIRE

    Mohammed Abdelmoneam Hemeida, Ahmed; Taha Elsayed Ahmed Abdelkader, Mohamed; Sergeant, Peter

    2015-01-01

    This paper discusses intensively the design considerations for the fractional slot axial flux permanent magnet synchronous (AFPMSMs) in order to work efficiently in the constant power speed range, also known as the field weakening (FW) region. The dominant parameter in the constant power speed region is called the characteristic current which equals the ratio of the magnet flux linkage over the synchronous inductance (− ψm/Ls). Several machine parameters is affecting the characteristic curren...

  6. A flux-scaling scenario for high-scale moduli stabilization in string theory

    OpenAIRE

    Ralph Blumenhagen; Anamaría Font; Michael Fuchs; Daniela Herschmann; Erik Plauschinn; Yuta Sekiguchi; Florian Wolf

    2015-01-01

    Tree-level moduli stabilization via geometric and non-geometric fluxes in type IIB orientifolds on Calabi-Yau manifolds is investigated. The focus is on stable non-supersymmetric minima, where all moduli are fixed except for some massless axions. The scenario includes the purely axionic orientifold-odd moduli. A set of vacua allowing for parametric control over the moduli vacuum expectation values and their masses is presented, featuring a specific scaling with the fluxes. Uplift mechanisms a...

  7. The Flux Variability of Markarian 501 in Very High Energy Gamma Rays

    CERN Document Server

    Quinn, J; Boyle, P J; Bradbury, S M; Breslin, A C; Buckley, J H; Burdett, A M; Gordo, J B; Carter-Lewis, D A; Catanese, M; Cawley, M F; Fegan, D J; Finley, J P; Gaidos, J A; Hall, T; Hillas, A M; Krennrich, F; Lamb, R C; Lessard, R W; Masterson, C; McEnery, J E; Moriarty, P; Rodgers, A J; Rose, H J; Samuelson, F W; Sembroski, G H; Srinivasan, R; Vasilev, V; Weekes, T C

    1999-01-01

    The BL Lacertae object Markarian 501 was identified as a source of gamma-ray emission at the Whipple Observatory in March 1995. Here we present a flux variability analysis on several times-scales of the 233 hour data set accumulated over 213 nights (from March 1995 to July 1998) with the Whipple Observatory 10 m atmospheric Cherenkov imaging telescope. In 1995, with the exception of a single night, the flux from Markarian 501 was constant on daily and monthly time-scales and had an average flux of only 10% that of the Crab Nebula, making it the weakest VHE source detected to date. In 1996, the average flux was approximately twice the 1995 flux and showed significant month-to-month variability. No significant day-scale variations were detected. The average gamma-ray flux above ~350 GeV in the 1997 observing season rose to 1.4 times that of the Crab Nebula -- 14 times the 1995 discovery level -- allowing a search for variability on time-scales shorter than one day. Significant hour-scale variability was present...

  8. Brookhaven highlights, July 1976-September 1978

    Energy Technology Data Exchange (ETDEWEB)

    1979-11-01

    Some of the most significant research accomplishments during this 27-month period are presented. Although some data are given, this report is primarily descriptive in outlook; detailed information on completed work should be sought from the references cited herein or from the usual sources of physics research information. The report is organized as follows: High-energy Physics (general introduction, physics research, accelerators, ISABELLE); Nuclear and Solid State Physics, and Chemistry; Life Sciences (biology, medicine); Applied Energy Science (energy and the environment, reactor systems and safety, National Nuclear Data Center, nuclear materials safeguards); Support Activities (applied mathematics, instrumentation, reactors, safety and environmental protection); and General and Administrative. 117 figures, 16 tables, 315 references. (RWR)

  9. Neutron spectrum measurements in the aluminum oxide filtered beam facility at the Brookhaven Medical Research Reactor

    International Nuclear Information System (INIS)

    Neutron spectrum measurements were performed on the aluminum oxide filter installed in the Brookhaven Medical Research Reactor (BMRR). For these measurements, activation foils were irradiated at the exit port of the beam facility. A technique based on dominant resonances in selected activation reactions was used to measure the epithermal neutron spectrum. The fast and intermediate-energy ranges of the neutron spectrum were measured by threshold reactions and 10B-shielded 235U fission reactions. Neutron spectral data were derived from the activation data by two approaches: (1) a short analysis which yields neutron flux values at the energies of the dominant or primary resonances in the epithermal activation reactions and integral flux data for neutrons above corresponding threshold or pseudo-threshold energies, and (2) the longer analysis which utilized all the activation data in a full-spectrum, unfolding process using the FERRET spectrum adjustment code. This paper gives a brief description of the measurement techniques, analysis methods, and the results obtained

  10. High time resolution studies of flux transfer events at the Earth's dayside magnetopause using Cluster data

    Science.gov (United States)

    Varsani, Ali; Owen, Christopher J.; Fazakerley, Andrew N.; Forsyth, Colin; Walsh, Andrew P.; Andre, Mats; Dandouras, Iannis; Lucek, Elizabeth

    2013-04-01

    Since launch in 2000, the four ESA Cluster spacecraft have each crossed the dayside magnetopause region thousands of times. Many previous studies presenting analysis of data from the mission, have contributed to a better understanding of the structure and dynamics of that interface and its associated boundary layers. While 2D electron pitch angle distributions (PAD) are routinely produced by the PEACE sensors on Cluster at spacecraft spin resolution (4s), the structures in this region are known to undergo changes on faster timescales than this, in response to both external drivers and internal dynamic processes. However, in certain circumstances, near-complete pitch angle distributions can be obtained at higher time resolution using Cluster burst mode data, facilitating a more detailed analysis of the particle behaviour near the magnetopause. In this paper we present an event during which the four spacecraft made outbound crossings through the low latitude boundary layer while the magnetic field orientation allowed a full pitch angle distribution of electrons to be constructed (every 1/8 s). The four Cluster spacecraft were in the 'multi-scale' formation with separations between individual pairs of spacecraft of either ~8000 or ~800 km. During the event in question, the Cluster spacecraft observed two flux transfer events (FTEs) and made a rapid (~16s) crossing of the magnetopause. The first FTE was most prominent in the C1 data a few minutes before the spacecraft crossed the magnetopause; and the second FTE was observed by C2 just before its magnetopause crossing. Additionally, C1 detected the signature associated with the second FTE in the magnetosheath, and the data from C3 show a disturbance in the low latitude boundary layer that also appears to be related to this FTE. We have utilized the high time resolution pitch angle distributions of electrons along with the high time resolution electric & magnetic data and ion distributions, to study in detail the

  11. Design and development of high flux pulsed neutron source for applications

    International Nuclear Information System (INIS)

    A dense plasma focus device based high flux pulsed neutron source has recently been made operational at Energetics and Electromagnetics Division, BARC Facility, Visakhapatnam. The 15kJ pulsed power system of this plasma focus device comprises of six modules (of ∼2.5 kJ each) and cumulatively delivers peak current in the range of 200kA to 500kA (depending upon load and operating parameters) in a quarter time period of about 5 μs. The major objective of preliminary phase of experiments was to investigate the neutron yield performance of this device at various deuterium filling gas pressures. At ∼10kJ operation, the average neutron yield has been found to be in the order of 109 neutrons/pulse in 4πsr for the deuterium filling gas pressure range of 4 to 6 mbar. The diagnostics used during these experiments were: 3He detector for the neutron yield measurements, plastic scintillator-photomultiplier detector for gathering the time resolved information of hard X-ray and neutron emission, and Rogowski coil for di/dt, current measurements. The main application objective of this high neutron yield dense plasma focus device development is: (i) to explore the feasibility study towards development Pulsed Fast Neutron Analysis (PFNA) system for explosive and contraband material detection and (ii) to conduct novel fusion reactor material studies, by investigating their suitability as plasma facing component materials in large upcoming fusion facilities. Detailed characterization experiments of this device are presently underway and will be reported in the conference. (author)

  12. Utilization of the High Flux Isotope Reactor at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Selby, Douglas L [ORNL; Bilheux, Hassina Z [ORNL; Meilleur, Flora [ORNL; Jones, Amy [ORNL; Bailey, William Barton [ORNL; Vandergriff, David H [ORNL

    2015-01-01

    This paper addresses several aspects of the scientific utilization of the Oak Ridge National Laboratory High Flux Isotope Reactor (HFIR). Topics to be covered will include: 1) HFIR neutron scattering instruments and the formal instrument user program; 2) Recent upgrades to the neutron scattering instrument stations at the reactor, and 3) eMod a new tool for addressing instrument modifications and providing configuration control and design process for scientific instruments at HFIR and the Spallation Neutron Source (SNS). There are 15 operating neutron instrument stations at HFIR with 12 of them organized into a formal user program. Since the last presentation on HFIR instruments at IGORR we have installed a Single Crystal Quasi-Laue Diffractometer instrument called IMAGINE; and we have made significant upgrades to HFIR neutron scattering instruments including the Cold Triple Axis Instrument, the Wide Angle Neutron Diffractometer, the Powder Diffractometer, and the Neutron Imaging station. In addition, we have initiated upgrades to the Thermal Triple Axis Instrument and the Bio-SANS cold neutron instrument detector system. All of these upgrades are tied to a continuous effort to maintain a high level neutron scattering user program at the HFIR. For the purpose of tracking modifications such as those mentioned and configuration control we have been developing an electronic system for entering instrument modification requests that follows a modification or instrument project through concept development, design, fabrication, installation, and commissioning. This system, which we call eMod, electronically leads the task leader through a series of questions and checklists that then identifies such things as ES&H and radiological issues and then automatically designates specific individuals for the activity review process. The system has been in use for less than a year and we are still working out some of the inefficiencies, but we believe that this will become a very

  13. Modeling and Simulations for the High Flux Isotope Reactor Cycle 400

    Energy Technology Data Exchange (ETDEWEB)

    Ilas, Germina [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); Chandler, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); Ade, Brian J [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); Sunny, Eva E [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); Betzler, Benjamin R [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); Pinkston, Daniel [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)

    2015-03-01

    A concerted effort over the past few years has been focused on enhancing the core model for the High Flux Isotope Reactor (HFIR), as part of a comprehensive study for HFIR conversion from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel. At this time, the core model used to perform analyses in support of HFIR operation is an MCNP model for the beginning of Cycle 400, which was documented in detail in a 2005 technical report. A HFIR core depletion model that is based on current state-of-the-art methods and nuclear data was needed to serve as reference for the design of an LEU fuel for HFIR. The recent enhancements in modeling and simulations for HFIR that are discussed in the present report include: (1) revision of the 2005 MCNP model for the beginning of Cycle 400 to improve the modeling data and assumptions as necessary based on appropriate primary reference sources HFIR drawings and reports; (2) improvement of the fuel region model, including an explicit representation for the involute fuel plate geometry that is characteristic to HFIR fuel; and (3) revision of the Monte Carlo-based depletion model for HFIR in use since 2009 but never documented in detail, with the development of a new depletion model for the HFIR explicit fuel plate representation. The new HFIR models for Cycle 400 are used to determine various metrics of relevance to reactor performance and safety assessments. The calculated metrics are compared, where possible, with measurement data from preconstruction critical experiments at HFIR, data included in the current HFIR safety analysis report, and/or data from previous calculations performed with different methods or codes. The results of the analyses show that the models presented in this report provide a robust and reliable basis for HFIR analyses.

  14. Study on high heat flux cooling by air-water flow driven by high speed air flow

    International Nuclear Information System (INIS)

    The effect of air injection into a subcooled water flow on boiling heat transfer and a critical heat flux (CHF) was examined experimentally. Experiments were conducted in the range of subcooling of 50 K, a superficial velocity of water and air Ul = 0,17 3,4 and Ug= 0 15,2 m/s, respectively. A test heat transfer surface was a 5 mm wide, 40 mm long and 0,2 mm thick stainless steel sheet embedded on the bottom wall of a 10 mm high and 20 mm wide rectangular flow channel. Nine times enhancement of the heat transfer in the non-boiling region was attained at the most by introducing an air flow into a water single-phase flow. The heat transfer augmentation in the non-boiling region was attained by less power increase than that in the case that only the water flow rate was increased. From the aspect of the power consumption and the heat transfer enhancement, the small air introduction in the low water flow rate region seemed more profitable, although the air introduction in the high water flow rate region and also the large air introduction were still effective in the augmentation of the heat transfer in the non-boiling region. (author)

  15. Establishing a Cost Basis for Converting the High Flux Isotope Reactor from High Enriched to Low Enriched Uranium Fuel

    International Nuclear Information System (INIS)

    Under the auspices of the Global Threat Reduction Initiative Reduced Enrichment for Research and Test Reactors Program, the National Nuclear Security Administration/Department of Energy (NNSA/DOE) has, as a goal, to convert research reactors worldwide from weapons grade to non-weapons grade uranium. The High Flux Isotope Reactor (HFIR) at Oak Ridge National Lab (ORNL) is one of the candidates for conversion of fuel from high enriched uranium (HEU) to low enriched uranium (LEU). A well documented business model, including tasks, costs, and schedules was developed to plan the conversion of HFIR. Using Microsoft Project, a detailed outline of the conversion program was established and consists of LEU fuel design activities, a fresh fuel shipping cask, improvements to the HFIR reactor building, and spent fuel operations. Current-value costs total $76 million dollars, include over 100 subtasks, and will take over 10 years to complete. The model and schedule follows the path of the fuel from receipt from fuel fabricator to delivery to spent fuel storage and illustrates the duration, start, and completion dates of each subtask to be completed. Assumptions that form the basis of the cost estimate have significant impact on cost and schedule.

  16. Establishing a Cost Basis for Converting the High Flux Isotope Reactor from High Enriched to Low Enriched Uranium Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Primm, Trent [ORNL; Guida, Tracey [University of Pittsburgh

    2010-02-01

    Under the auspices of the Global Threat Reduction Initiative Reduced Enrichment for Research and Test Reactors Program, the National Nuclear Security Administration /Department of Energy (NNSA/DOE) has, as a goal, to convert research reactors worldwide from weapons grade to non-weapons grade uranium. The High Flux Isotope Reactor (HFIR) at Oak Ridge National Lab (ORNL) is one of the candidates for conversion of fuel from high enriched uranium (HEU) to low enriched uranium (LEU). A well documented business model, including tasks, costs, and schedules was developed to plan the conversion of HFIR. Using Microsoft Project, a detailed outline of the conversion program was established and consists of LEU fuel design activities, a fresh fuel shipping cask, improvements to the HFIR reactor building, and spent fuel operations. Current-value costs total $76 million dollars, include over 100 subtasks, and will take over 10 years to complete. The model and schedule follows the path of the fuel from receipt from fuel fabricator to delivery to spent fuel storage and illustrates the duration, start, and completion dates of each subtask to be completed. Assumptions that form the basis of the cost estimate have significant impact on cost and schedule.

  17. Particulate generation during disruption simulation on the SIRENS high heat flux facility

    Science.gov (United States)

    Sharpe, John Phillip

    2000-12-01

    Successful implementation of advanced electrical power generation technology into the global marketplace requires at least two fundamental ideals: cost effectiveness and the guarantee of public safety. One general area of concern for fusion devices is the production of particulate, often referred to as dust or aerosol, from material exposed to high energy density fusion plasma. This dust may be radiologically activated and/or chemically toxic, and, if released to the environment, could become a hazard to the public. The goal of this investigation was to provide insight into the production and transport of particulate generated during the event of extreme heat loads to surfaces directly exposed to high energy density plasma. A step towards achieving this goal was an experiment campaign carried out with the S&barbelow;urface I&barbelow;nteṞaction E&barbelow;xperiment at Ṉorth Carolina S&barbelow;tate (SIRENS), a facility used for high heat flux experiments. These experiments involved exposing various materials, including copper, stainless steel 316, tungsten, aluminum, graphite (carbon), and mixtures of carbon and metals, to the high energy density plasma of the SIRENS source section. Comparison of simulation results with experiment observations provides an understanding of the physical mechanisms forming the particulate and indicates if mechanisms other than those in the model were present in the experiment. Key results from this comparison were: the predicted amount of mass mobilized from the source section was generally much lower than that measured, the calculated and measured particle count median diameters were similar at various locations in the expansion chamber, and the measured standard deviations were larger than those predicted by the model. These results implicate that other mechanisms (e.g., mobilization of melted material) in addition to ablation were responsible for mass removal in the source section, a large number of the measured particles were

  18. The effect of hygroscopicity on sea-spray aerosol fluxes: a comparison of high-rate and bulk correction methods

    Directory of Open Access Journals (Sweden)

    D. A. J. Sproson

    2012-09-01

    Full Text Available The eddy covariance technique is the most direct of the methods that have been used to measure the flux of sea-spray aerosol between the ocean and atmosphere, but has been applied in only a handful of studies. However, unless the aerosol is dried before the eddy covariance measurements are made, the hygroscopic nature of sea-spray may combine with a relative humidity flux to result in a bias in the calculated aerosol flux. "Bulk" methods have been presented to account for this bias, however they rely on assumptions of the shape of the aerosol spectra which may not be valid for near-surface measurements of sea-spray.

    Here we describe a method of correcting aerosol spectra for relative humidity induced size variations at the high frequency (10 Hz measurement timescale, where counting statistics are poor and the spectral shape cannot be well represented by a simple power law. Such a correction allows the effects of hygroscopicity and relative humidity flux on the aerosol flux to be explicitly evaluated and compared to the bulk corrections, both in their original form and once reformulated to better represent the measured mean aerosol spectra. In general, the bulk corrections – particularly when reformulated for the measured mean aerosol spectra – perform relatively well, producing flux corrections of the right sign and approximate magnitude. However, there are times when the bulk methods either significantly over- or underestimate the required flux correction. We thus conclude that, where possible, relative humidity corrections should be made at the measurement frequency.

  19. Job/task analysis for I ampersand C [Instrumentation and Controls] instrument technicians at the High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    To comply with Department of Energy Order 5480.XX (Draft), a job/task analysis was initiated by the Maintenance Management Department at Oak Ridge National Laboratory (ORNL). The analysis was applicable to instrument technicians working at the ORNL High Flux Isotope Reactor (HFIR). This document presents the procedures and results of that analysis. 2 refs., 2 figs

  20. US-Japan workshop Q-181 on high heat flux components and plasma-surface interactions for next devices: Proceedings

    International Nuclear Information System (INIS)

    This report contain viewgraphs of papers from the following sessions: plasma facing components issues for future machines; recent PMI results from several tokamaks; high heat flux technology; plasma facing components design and applications; plasma facing component materials and irradiation damage; boundary layer plasma; plasma disruptions; conditioning and tritium; and erosion/redeposition