Sample records for thermonuclear experimental reactor

  1. TRANSP simulations of International Thermonuclear Experimental Reactor plasmas

    E-Print Network [OSTI]

    Budny, Robert

    TRANSP simulations of International Thermonuclear Experimental Reactor plasmas R. V. Budny, D. C-consistent models for plasmas within the separatrix surface in the International Thermonuclear Experimental Reactor. INTRODUCTION One of the goals for the International Thermonuclear Experimental Reactor ITER is the production

  2. Industrial opportunities on the International Thermonuclear Experimental Reactor (ITER) project

    SciTech Connect (OSTI)

    Ellis, W.R. [Raytheon Engineers and Constructors, New York, NY (United States)

    1996-12-01T23:59:59.000Z

    Industry has been a long-term contributor to the magnetic fusion program, playing a variety of important roles over the years. Manufacturing firms, engineering-construction companies, and the electric utility industry should all be regarded as legitimate stakeholders in the fusion energy program. In a program focused primarily on energy production, industry`s future roles should follow in a natural way, leading to the commercialization of the technology. In a program focused primarily on science and technology, industry`s roles, in the near term, should be, in addition to operating existing research facilities, largely devoted to providing industrial support to the International Thermonuclear Experimental Reactor (ITER) Project. Industrial opportunities on the ITER Project will be guided by the amount of funding available to magnetic fusion generally, since ITER is funded as a component of that program. The ITER Project can conveniently be discussed in terms of its phases, namely, the present Engineering Design Activities (EDA) phase, and the future (as yet not approved) construction phase. 2 refs., 3 tabs.

  3. ITER: The International Thermonuclear Experimental Reactor and the Nuclear Weapons Proliferation Implications of Thermonuclear-Fusion Energy Systems

    E-Print Network [OSTI]

    André Gsponer; Jean-pierre Hurni

    2004-01-01T23:59:59.000Z

    This paper contains two parts: (I) A list of “points ” highlighting the strategic-political and militarytechnical reasons and implications of the very probable siting of ITER (the International Thermonuclear Experimental Reactor) in Japan, which should be confirmed sometimes in early 2004. (II) A technical analysis of the nuclear weapons proliferation implications of inertial- and magnetic-confinement fusion systems substantiating the technical points highlighted in the first part, and showing that while full access to the physics of thermonuclear weapons is the main implication of ICF, full access to large-scale tritium technology is the main proliferation impact of MCF. The conclusion of the paper is that siting ITER in a country such as Japan, which already has a large separated-plutonium stockpile, and an ambitious laser-driven ICF program (comparable in size and quality to those of the United States or France) will considerably increase its latent (or virtual) nuclear weapons proliferation status, and foster further nuclear proliferation throughout the world. The safety and environmental problems related to the operation of largescale fusion facilities such as ITER (which contain massive amounts of hazardous and/or radioactive materials such as tritium, lithium, and beryllium, as well as neutron-activated structural materials) are not addressed in this paper.

  4. US ITER (International Thermonuclear Experimental Reactor) shield and blanket design activities

    SciTech Connect (OSTI)

    Baker, C.C.

    1988-08-01T23:59:59.000Z

    This paper summarizes nuclear-related work in support of the US effort for the International Thermonuclear Experimental Reactor (ITER) Study. Primary tasks carried out during the past year include design improvements of the inboard shield developed for the TIBER concept, scoping studies of a variety of tritium breeding blanket options, development of necessary design guidelines and evaluation criteria for the blanket options, further safety considerations related to nuclear components, and issues regarding structural materials for an ITER device. The blanket concepts considered are the aqueous/Li salt solution, a water-cooled, solid breeder blanket, a helium-cooled, solid-breeder blanket, a blanket cooled by helium containing lithium-bearing particulates, and a blanket concept based on breeding tritium from He/sup 3/. 1 ref., 2 tabs.

  5. Review of the International Thermonuclear Experimental Reactor (ITER) detailed design report

    SciTech Connect (OSTI)

    NONE

    1997-04-18T23:59:59.000Z

    Dr. Martha Krebs, Director, Office of Energy Research at the US Department of Energy (DOE), wrote to the Fusion Energy Sciences Advisory Committee (FESAC), in letters dated September 23 and November 6, 1996, requesting that FESAC review the International Thermonuclear Experimental Reactor (ITER) Detailed Design Report (DDR) and provide its view of the adequacy of the DDR as part of the basis for the United States decision to enter negotiations with the other interested Parties regarding the terms and conditions for an agreement for the construction, operations, exploitation and decommissioning of ITER. The letter from Dr. Krebs, referred to as the Charge Letter, provided context for the review and a set of questions of specific interest.

  6. The Japan Times Printer Friendly Articles France has won the competition to host the International Thermonuclear Experimental Reactor (ITER), the world's first nuclear-

    E-Print Network [OSTI]

    the International Thermonuclear Experimental Reactor (ITER), the world's first nuclear- fusion reactor. Japan fought wins by withdrawing ITER bid Thermonuclear fusion utilizes the same process that powers the sun -- nuclear-fusion reactions -- to produce energy. Scientists at the ITER plant will create nuclear-fusion

  7. Economic impacts on the United States of siting decisions for the international thermonuclear experimental reactor

    SciTech Connect (OSTI)

    Peerenboom, J.P.; Hanson, M.E.; Huddleston, J.R. [and others

    1996-08-01T23:59:59.000Z

    This report presents the results of a study that examines and compares the probable short-term economic impacts of the International Thermonuclear Experimental Reactor (ITER) on the United States (U.S.) if (1) ITER were to be sited in the U.S., or (2) ITER were to be sited in one of the other countries that, along with the U.S., is currently participating in the ITER program. Life-cycle costs associated with ITER construction, operation, and decommissioning are analyzed to assess their economic impact. A number of possible U.S. host and U.S. non-host technology and cost-sharing arrangements with the other ITER Parties are examined, although cost-sharing arrangements and the process by which the Parties will select a host country and an ITER site remain open issues. Both national and local/regional economic impacts, as measured by gross domestic product, regional output, employment, net exports, and income, are considered. These impacts represent a portion of the complex, interrelated set of economic considerations that characterize U.S. host and U.S. non-host participation in ITER. A number of other potentially important economic and noneconomic considerations are discussed qualitatively.

  8. Thermonuclear Reflect AB-Reactor

    E-Print Network [OSTI]

    Alexander Bolonkin

    2008-03-26T23:59:59.000Z

    The author offers a new kind of thermonuclear reflect reactor. The remarkable feature of this new reactor is a three net AB reflector, which confines the high temperature plasma. The plasma loses part of its energy when it contacts with the net but this loss can be compensated by an additional permanent plasma heating. When the plasma is rarefied (has a small density), the heat flow to the AB reflector is not large and the temperature in the triple reflector net is lower than 2000 - 3000 K. This offered AB-reactor has significantly less power then the currently contemplated power reactors with magnetic or inertial confinement (hundreds-thousands of kW, not millions of kW). But it is enough for many vehicles and ships and particularly valuable for tunnelers, subs and space apparatus, where air to burn chemical fuel is at a premium or simply not available. The author has made a number of innovations in this reactor, researched its theory, developed methods of computation, made a sample computation of typical project. The main point of preference for the offered reactor is its likely cheapness as a power source. Key words: Micro-thermonuclear reactor, Multi-reflex AB-thermonuclear reactor, Self-magnetic AB-thermonuclear reactor, aerospace thermonuclear engine.

  9. First operation with the JET International Thermonuclear Experimental Reactor-like wall

    SciTech Connect (OSTI)

    Neu, R. [EFDA-CSU, Boltzmannstr. 2, 85748 Garching (Germany) [EFDA-CSU, Boltzmannstr. 2, 85748 Garching (Germany); Max-Planck-Institut für Plasmaphysik, Euratom Association, Boltzmannstr. 2, 85748 Garching (Germany); Arnoux, G.; Beurskens, M.; Challis, C.; Giroud, C.; Lomas, P.; Maddison, G.; Matthews, G.; Mayoral, M.-L.; Meigs, A.; Rimini, F. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)] [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Bobkov, V.; Dux, R.; Hobirk, J.; Lang, P.; Maggi, C.; Pütterich, T.; Sertoli, M.; Sieglin, B. [Max-Planck-Institut für Plasmaphysik, Euratom Association, Boltzmannstr. 2, 85748 Garching (Germany)] [Max-Planck-Institut für Plasmaphysik, Euratom Association, Boltzmannstr. 2, 85748 Garching (Germany); Brezinsek, S. [IEK-4, Association EURATOM/Forschungszentrum Jülich GmbH, Jülich 52425 (Germany)] [IEK-4, Association EURATOM/Forschungszentrum Jülich GmbH, Jülich 52425 (Germany); and others

    2013-05-15T23:59:59.000Z

    To consolidate International Thermonuclear Experimental Reactor (ITER) design choices and prepare for its operation, Joint European Torus (JET) has implemented ITER's plasma facing materials, namely, Be for the main wall and W in the divertor. In addition, protection systems, diagnostics, and the vertical stability control were upgraded and the heating capability of the neutral beams was increased to over 30 MW. First results confirm the expected benefits and the limitations of all metal plasma facing components (PFCs) but also yield understanding of operational issues directly relating to ITER. H-retention is lower by at least a factor of 10 in all operational scenarios compared to that with C PFCs. The lower C content (? factor 10) has led to much lower radiation during the plasma burn-through phase eliminating breakdown failures. Similarly, the intrinsic radiation observed during disruptions is very low, leading to high power loads and to a slow current quench. Massive gas injection using a D{sub 2}/Ar mixture restores levels of radiation and vessel forces similar to those of mitigated disruptions with the C wall. Dedicated L-H transition experiments indicate a 30% power threshold reduction, a distinct minimum density, and a pronounced shape dependence. The L-mode density limit was found to be up to 30% higher than for C allowing stable detached divertor operation over a larger density range. Stable H-modes as well as the hybrid scenario could be re-established only when using gas puff levels of a few 10{sup 21} es{sup ?1}. On average, the confinement is lower with the new PFCs, but nevertheless, H factors up to 1 (H-Mode) and 1.3 (at ?{sub N}?3, hybrids) have been achieved with W concentrations well below the maximum acceptable level.

  10. ITER: The International Thermonuclear Experimental Reactor and the Nuclear Weapons Proliferation

    E-Print Network [OSTI]

    André Gsponer; Jean-pierre Hurni

    2004-01-01T23:59:59.000Z

    militarytechnical reasons and implications of the very probable siting of ITER (the International Thermonuclear

  11. 03/01/2006 09:51 AMLoading "People's Daily Online --Chinese experimental thermonuclear reactor on discharge test in July" Page 1 of 1http://english.people.com.cn/200603/01/print20060301_247035.html

    E-Print Network [OSTI]

    experimental thermonuclear reactor on discharge test in July China's new generation experimental Tokamak fusion03/01/2006 09:51 AMLoading "People's Daily Online -- Chinese experimental thermonuclear reactor successful, it would be the world's first experimental nuclear fusion device to come into operation. Li

  12. A E Costley, US/ITER Town meeting, San Diego, 22 April 2004 N 55 IP 57 04-04-30 F 1 International Thermonuclear Experimental Reactor

    E-Print Network [OSTI]

    Thermonuclear Experimental Reactor Overview of ITER Diagnostics and Progress Towards Procurement A E Costley/C) Reflectometers for Divertor Plasma Optical/IR Systems Fast Wave Reflectometry (N/C) Thomson Scattering (Core Interferom./Polarimetric System Residual Gas Analyzers Polarimetric System (Pol. Field Meas) IR Thermography

  13. Thermonuclear reactor may begin to be built 2004 21.02.2004, 00.55

    E-Print Network [OSTI]

    Thermonuclear reactor may begin to be built 2004 21.02.2004, 00.55 MOSCOW, February 20 (Itar-Tass) -- Construction of what may become the world's first-ever thermonuclear experimental reactor (ITER) may begin Institute, which developed the thermonuclear reactor, Yevgeny Velikhov said. The Russian panel at the Vienna

  14. ITER --"INTERNATIONAL THERMONUCLEAR EXPERIMENTAL RESEARCH PROGRAM".

    E-Print Network [OSTI]

    ITER -- "INTERNATIONAL THERMONUCLEAR EXPERIMENTAL RESEARCH PROGRAM". ORGANIZATION TO DIRECT WORLD plasmas and thermonuclear burn processes (cost -$1.5-36)2. (2) An expanded, more ambitious international Thermonuclear Experimental Research Program" by L. J. Perkins #12;NORMAL-CONDUCTING COPPER OPTIONS FOR THE ITER

  15. PUBLISHED VERSION Design, performance, and grounding aspects of the International Thermonuclear Experimental

    E-Print Network [OSTI]

    PUBLISHED VERSION Design, performance, and grounding aspects of the International Thermonuclear, performance, and grounding aspects of the International Thermonuclear Experimental Reactor ion cyclotron range Thermonuclear Experimental Reactor ion cyclotron range of frequencies antenna F. Durodie,1,a) P. Dumortier,1 M

  16. Micro -Thermonuclear AB-Reactors for Aerospace

    E-Print Network [OSTI]

    Alexander Bolonkin

    2007-01-08T23:59:59.000Z

    The author offers several innovations that he first suggested publicly early in 1983 for the AB multi-reflex engine, space propulsion, getting energy from plasma, etc. (see: A. Bolonkin, Non-Rocket Space Launch and Flight, Elsevier, London, 2006, Chapters 12, 3A). It is the micro-thermonuclear AB-Reactors. That is new micro-thermonuclear reactor with very small fuel pellet that uses plasma confinement generated by multi-reflection of laser beam or its own magnetic field. The Lawson criterion increases by hundreds of times. The author also suggests a new method of heating the power-making fuel pellet by outer electric current as well as new direct method of transformation of ion kinetic energy into harvestable electricity. These offered innovations dramatically decrease the size, weight and cost of thermonuclear reactor, installation, propulsion system and electric generator. Non-industrial countries can produce these researches and constructions. Currently, the author is researching the efficiency of these innovations for two types of the micro-thermonuclear reactors: multi-reflection reactor (ICF) and self-magnetic reactor (MCF).

  17. New AB-Thermonuclear Reactor for Aerospace

    E-Print Network [OSTI]

    Alexander Bolonkin

    2007-06-14T23:59:59.000Z

    There are two main methods of nulcear fusion: inertial confinement fusion (ICF) and magnetic confinement fusion (MCF). Existing thermonuclear reactors are very complex, expensive, large, and heavy. They cannot achieve the Lawson creterion. The author offers an innovation. ICF has on the inside surface of the shell-shaped combustion chamber a covering of small Prism Reflectors (PR) and plasma reflector. These prism reflectors have a noteworthy advantage, in comparison with conventional mirror and especially with conventional shell: they multi-reflect the heat and laser radiation exactly back into collision with the fuel target capsule (pellet). The plasma reflector reflects the Bremsstrahlung radiation. The offered innovation decreases radiation losses, creates significant radiation pressure and increases the reaction time. The Lawson criterion increases by hundreds of times. The size, cost, and weight of a typical installation will decrease by tens of times. The author is researching the efficiency of these innovations. Keywords: Thermonuclear reactor, Multi-reflex AB-thermonuclear reactor, aerospace thermonuclear engine. This work is presented as paper AIAA-2006-7225 to Space-2006 Conference, 19-21 September, 2006, San Jose, CA, USA.

  18. New material for thermonuclear fusion reactors | EurekAlert! Science News

    E-Print Network [OSTI]

    ... Jan-2012 New material for thermonuclear fusion reactors ... to develop new materials for thermonuclear fusion reactors. Their research focuses ... to develop new materials for thermonuclear fusion reactors. Their research focuses ...

  19. Recent Steps Towards a Controlled Thermonuclear Fusion Reactor with Results from the JET Tokamak Device

    E-Print Network [OSTI]

    Recent Steps Towards a Controlled Thermonuclear Fusion Reactor with Results from the JET Tokamak Device

  20. Iran cannot have claimed to be building a thermonuclear reactor -To build a thermonuclear reactor by its own efforts is a task absolutely beyond Iran's

    E-Print Network [OSTI]

    Iran cannot have claimed to be building a thermonuclear reactor - expert To build a thermonuclear at the Institute of Nuclear Fusion of the Russian Research Center Kurchatov Institute, said: "Our specialists misunderstood." Work to create a thermonuclear reactor has been pursued in all leading countries for several

  1. Radiation-Resistant WDM Optical Link for Thermonuclear Fusion Reactor Instrumentation

    E-Print Network [OSTI]

    A. Fernandez Fernandez; Ez Fern; P. Borgermans; B. Brichard; P. Borgermans; A. I. Gusarov; M. Van Uffelen; P. Megret; M. Decréton; M. Blondel; A. Delchambre

    2001-01-01T23:59:59.000Z

    The future International Thermonuclear Experimental Reactor (ITER) is a complex installation that will require permanent monitoring and frequent maintenance operations. The high-gamma dose rates, the high neutron fluence, and other radiological hazards call for the use of remote-handled equipment

  2. alamos thermonuclear weapon: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Thermonuclear Experimental Reactor and the Nuclear Weapons Proliferation Implications of Thermonuclear-Fusion Energy Systems CiteSeer Summary: This paper contains two parts: (I) A...

  3. http://www3.nhk.or.jp/news/2003/12/27/k20031227000018.html 3 national visits related to proposed site for experimental reactor

    E-Print Network [OSTI]

    Minister communication meeting on Japanese Proposed site for Thermonuclear fusion experimental reactor realize the Japanese proposed site for the international thermonuclear fusion experimental reactor (ITER international support for experimental reactor ITER of the fusion centering on proposed site in Aomori

  4. Thermonuclear Fusion Research Progress and the Way to the Reactor

    SciTech Connect (OSTI)

    Koch, Raymond [Laboratory for Plasma Physics, Royal Military Academy, Association EURATOM - Belgian State, 1000 Brussels (Belgium)

    2006-06-08T23:59:59.000Z

    The paper reviews the progress of fusion research and its prospects for electricity generation. It starts with a reminder of the principles of thermonuclear fusion and a brief discussion of its potential role in the future of the world energy production. The reactions allowing energy production by fusion of nuclei in stars and on earth and the conditions required to sustain them are reviewed. At the high temperatures required for fusion (hundred millions kelvins), matter is completely ionized and has reached what is called its 4th state: the plasma state. The possible means to achieve these extreme temperatures is discussed. The remainder of the paper focuses on the most promising of these approaches, magnetic confinement. The operating principles of the presently most efficient machine of this type -- the tokamak -- is described in some detail. On the road to producing energy with fusion, a number of obstacles have to be overcome. The plasma, a fluid that reacts to electromagnetic forces and carries currents and charges, is a complex medium. Fusion plasma is strongly heated and is therefore a good example of a system far from equilibrium. A wide variety of instabilities can grow in this system and lead to self-organized structures and spontaneous cycles. Turbulence is generated that degrades the confinement and hinders easy achievement of long lasting hot plasmas. Physicists have learned how to quench turbulence, thereby creating sort of insulating bottles inside the plasma itself to circumvent this problem. The recent history of fusion performance is outlined and the prospect of achieving power generation by fusion in a near future is discussed in the light of the development of the 'International Tokamak Experimental Reactor' project ITER.

  5. ROLE OF FUSION ENERGY FOR THE 21 CENTURY ENERGY MARKET AND DEVELOPMENT STRATEGY WITH INTERNATIONAL THERMONUCLEAR EXPERIMENTAL

    E-Print Network [OSTI]

    THERMONUCLEAR EXPERIMENTAL REACTOR Rôle de l'énergie de fusion dans la production énergétique du 21 e siècle etROLE OF FUSION ENERGY FOR THE 21 CENTURY ENERGY MARKET AND DEVELOPMENT STRATEGY WITH INTERNATIONAL be improved to contribute to this issue. Fusion is an energy source of the Sun and the Star. It is a quite

  6. Stars as thermonuclear reactors: their fuels and ashes

    E-Print Network [OSTI]

    A. Ray

    2004-05-28T23:59:59.000Z

    Atomic nuclei are transformed into each other in the cosmos by nuclear reactions inside stars: -- the process of nucleosynthesis. The basic concepts of determining nuclear reaction rates inside stars and how they manage to burn their fuel so slowly most of the time are discussed. Thermonuclear reactions involving protons in the hydrostatic burning of hydrogen in stars are discussed first. This is followed by triple alpha reactions in the helium burning stage and the issues of survival of carbon and oxygen in red giant stars connected with nuclear structure of oxygen and neon. Advanced stages of nuclear burning in quiescent reactions involving carbon, neon, oxygen and silicon are discussed. The role of neutron induced reactions in nucleosynthesis beyond iron is discussed briefly, as also the experimental detection of neutrinos from SN 1987A which confirmed broadly the ideas concerning gravitational collapse leading to a supernova.

  7. Application of variational techniques for parametric studies of steady-state controlled thermonuclear reactor blankets 

    E-Print Network [OSTI]

    Pearce, James David

    1975-01-01T23:59:59.000Z

    APPLICATION OF VARIATIONAL TECHNIQUES FOR PARAMETRIC STUDIES OF STEADY-STATE CONTROLLED THERMONUCLEAR REACTOR BLANKETS A Thesis JAMES DAVID PEARCE Submitted to the Graduate College of Texas A6M University in partial fulfillment... of the requirement for the degree of MASTER OP SCIENCE May 1975 Ma)or Subject: Nuclear Engineering APPLICATION OF VARIATIONAL TECHNIQUES FOR PARAMETRIC STUDIES OF STEADY-STATE CONTROLLED THERMONUCLEAR REACTOR BLANKETS A Thesis by JAMES DAVID PEARCE Approved...

  8. Application of variational techniques for parametric studies of steady-state controlled thermonuclear reactor blankets

    E-Print Network [OSTI]

    Pearce, James David

    1975-01-01T23:59:59.000Z

    APPLICATION OF VARIATIONAL TECHNIQUES FOR PARAMETRIC STUDIES OF STEADY-STATE CONTROLLED THERMONUCLEAR REACTOR BLANKETS A Thesis JAMES DAVID PEARCE Submitted to the Graduate College of Texas A6M University in partial fulfillment... of the requirement for the degree of MASTER OP SCIENCE May 1975 Ma)or Subject: Nuclear Engineering APPLICATION OF VARIATIONAL TECHNIQUES FOR PARAMETRIC STUDIES OF STEADY-STATE CONTROLLED THERMONUCLEAR REACTOR BLANKETS A Thesis by JAMES DAVID PEARCE Approved...

  9. anaerobic reactor systems: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Thermonuclear Experimental Reactor and the Nuclear Weapons Proliferation Implications of Thermonuclear-Fusion Energy Systems CiteSeer Summary: This paper contains two parts: (I) A...

  10. advanced converter reactors: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CERN Preprints Summary: The International Thermonuclear Experimental Reactor (ITER) is a thermonuclear fusion experiment designed to provide long deuterium tritium burning...

  11. annular reactor system: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Thermonuclear Experimental Reactor and the Nuclear Weapons Proliferation Implications of Thermonuclear-Fusion Energy Systems CiteSeer Summary: This paper contains two parts: (I) A...

  12. Astrophysical thermonuclear functions

    E-Print Network [OSTI]

    William J. Anderson; Hans J. Haubold; Arak Mathai Mathai

    1993-08-23T23:59:59.000Z

    Stars are gravitationally stabilized fusion reactors changing their chemical composition while transforming light atomic nuclei into heavy ones. The atomic nuclei are supposed to be in thermal equilibrium with the ambient plasma. The majority of reactions among nuclei leading to a nuclear transformation are inhibited by the necessity for the charged participants to tunnel through their mutual Coulomb barrier. As theoretical knowledge and experimental verification of nuclear cross sections increases it becomes possible to refine analytic representations for nuclear reaction rates. Over the years various approaches have been made to derive closed-form representations of thermonuclear reaction rates (Critchfield 1972, Haubold and John 1978, Haubold, Mathai and Anderson 1987). They show that the reaction rate contains the astrophysical cross section factor and its derivatives which has to be determined experimentally, and an integral part of the thermonuclear reaction rate independent from experimental results which can be treated by closed-form representation techniques in terms of generalized hypergeometric functions. In this paper mathematical/statistical techniques for deriving closed-form representations of thermonuclear functions will be summarized and numerical results for them will be given. The separation of thermonuclear functions from thermonuclear reaction rates is our preferred result. The purpose of the paper is also to compare numerical results for approximate and closed-form representations of thermonuclear functions. This paper completes the work of Haubold, Mathai, and Anderson (1987).

  13. Thermonuclear inverse magnetic pumping power cycle for stellarator reactor

    DOE Patents [OSTI]

    Ho, Darwin D. (Pleasanton, CA); Kulsrud, Russell M. (Princeton, NJ)

    1991-01-01T23:59:59.000Z

    The plasma column in a stellarator is compressed and expanded alternatively in minor radius. First a plasma in thermal balance is compressed adiabatically. The volume of the compressed plasma is maintained until the plasma reaches a new thermal equilibrium. The plasma is then expanded to its original volume. As a result of the way a stellarator works, the plasma pressure during compression is less than the corresponding pressure during expansion. Therefore, negative work is done on the plasma over a complete cycle. This work manifests itself as a back-voltage in the toroidal field coils. Direct electrical energy is obtained from this voltage. Alternatively, after the compression step, the plasma can be expanded at constant pressure. The cycle can be made self-sustaining by operating a system of two stellarator reactors in tandem. Part of the energy derived from the expansion phase of a first stellarator reactor is used to compress the plasma in a second stellarator reactor.

  14. EU to build experimental fusion reactor Associated Press, THE JERUSALEM POST Sep 25, 2006

    E-Print Network [OSTI]

    EU to build experimental fusion reactor Associated Press, THE JERUSALEM POST Sep 25, 2006 European Union nations on Monday endorsed a pact to build an experimental fusion reactor with the aim, China, Japan, South Korea and Russia - also aim to ratify the International Thermonuclear Experimental

  15. Lower hybrid current drive at plasma densities required for thermonuclear reactors

    SciTech Connect (OSTI)

    Cesario, R.; Cardinali, A.; Castaldo, C.; Tuccillo, A. A.; Amicucci, L. [Associazione EURATOM/ENEA sulla Fusione, Centro Ricerche Frascati, 00044 Frascati (Italy)

    2011-12-23T23:59:59.000Z

    Driving current in high-density plasmas is essential for the progress of thermonuclear fusion energy research based on the tokamak concept. The lower hybrid current drive (LHCD) effect, is potentially the most suitable tool for driving current at large plasma radii, consistent with the needs of ITER steady state scenario. Unfortunately, experiments at reactor grade high plasma densities with kinetic profiles approaching those required for ITER, have shown problems in penetration of the LH power into the core plasma. These plasmas represent a basic reference for designing possible methods useful for assessing the LHCD concept in ITER. On the basis of the phenomenology observed during LHCD experiments carried out in different machines, and model of the spectral broadening effect due to parametric instability, an interpretation and possible solution of the related important problem is presented.

  16. Lower hybrid current drive at densities required for thermonuclear reactors R. Cesario 1), L. Amicucci 2), M. L. Apicella 1), G. Calabr 1), A. Cardinali 1), C. Castaldo 1),

    E-Print Network [OSTI]

    Vlad, Gregorio

    EXW/P7-02 Lower hybrid current drive at densities required for thermonuclear reactors R@frascati.enea.it Abstract. For the progress of the thermonuclear fusion energy research based on the tokamak concept in ITER (International Thermonuclear Experiment Reactor) at relatively high plasma densities also

  17. advanced fusion reactors: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Collaborators 7 China To Build Its Own Fusion Reactor ENERGY TECH Plasma Physics and Fusion Websites Summary: Thermonuclear Experimental Reactor project reached agreement in...

  18. Feedback control of major disruptions in International Thermonuclear Experimental Reactor

    SciTech Connect (OSTI)

    Sen, A. K. [Plasma Physics Laboratory, Columbia University, New York, New York 10026 (United States)

    2011-08-15T23:59:59.000Z

    It is argued that major disruptions in ITER can be avoided by the feedback control of the causative MHD precursors. The sensors will be 2D-arrays of ECE detectors and the suppressors will be modulated ECH beams injected radially to produce non-thermal radial pressures to counter the radial dynamics of MHD modes. The appropriate amplitude and phase of this signal can stabilize the relevant MHD modes and prevent their evolution to a major disruption. For multimode MHD precursors, an optimal feedback scheme with a Kalman filter is discussed.

  19. E-Print Network 3.0 - advanced research reactor Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to build the world's most advanced nuclear fusion reactor... ) International Thermonuclear Experimental Reactor (ITER), which will be built at Cadarache, near the...

  20. Thermonuclear fusion

    E-Print Network [OSTI]

    Thermonuclear fusion is a way to achieve nuclear fusion by using extremely high temperatures. There are two forms of thermonuclear fusion: uncontrolled, in which the resulting energy is released in an uncontrolled manner, as it is in thermonuclear weapon...

  1. arsenal production reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to total production in India V. Dinesh Kumar 42 TRANSP simulations of International Thermonuclear Experimental Reactor plasmas Plasma Physics and Fusion Websites Summary:...

  2. Astrophysical thermonuclear functions

    E-Print Network [OSTI]

    W. J. Anderson; H. J. Haubold; A. M. Mathai

    1994-02-08T23:59:59.000Z

    As theoretical knowledge and experimental verification of nuclear cross sections increases it becomes possible to refine analytic representations for nuclear reaction rates. In this paper mathematical/statistical techniques for deriving closed-form representations of thermonuclear functions are summarized and numerical results for them are given.The purpose of the paper is also to compare numerical results for approximate and closed-form representations of thermonuclear functions.

  3. E-Print Network 3.0 - atomic reactors chaines Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to join round-the-world computer network ring. 28.01.2004, 21.08 Summary: thermonuclear experimental reactor (ITER) project have an opportunity to offer technical...

  4. E-Print Network 3.0 - auxiliary reactor area-1 Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    plans eyed for fusion project site Summary: said. The six parties involved in the Thermonuclear Experimental Reactor (ITER) project have been... unable to agree where to locate...

  5. E-Print Network 3.0 - advanced reactor technology Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Op-ed Letters... to iron out their differences over the site of the International Thermonuclear Experimental Reactor... . Russia sticks to its guns, backs France for fusion...

  6. Concept of a thermonuclear reactor based on gravity retention of high-temperature plasma

    E-Print Network [OSTI]

    S. I. Fisenko; I. S. Fisenko

    2007-05-27T23:59:59.000Z

    In the present paper the realization of the obtained results in relation to the dense high- temperature plasma of multivalent ions including experimental data interpretation is discussed.

  7. Radiation Hardness of Passive Fibre Optic Components for the Future Thermonuclear Fusion Reactor

    E-Print Network [OSTI]

    A. Fernandez Fernandez F. Berghmans; A. Fern; Ez Fern; M. Decréton; P. Mégret; M. Blondel; A. Delchambre; Ez A; F. Berghmans A; B. Brichard; M. Van Uffelen

    2001-01-01T23:59:59.000Z

    thermon uclearfusion reactor ITER will require remote-hanA#0 equipmen t to monNNfl its operation an to allow hazard-freemand-freexAN durin itsfrequen tmain ten3# periods. Heavy shielded umbilicals will be required tocon5N3 thesen2A5 an the actuators with theirinrx0flNj tation Multiplexin sen#0 signfl3 turn out to beessen tial to ease the umbilicalmancalx5 t. We arecon33NxF0# fibre optic technxfljN , with its in trinfl# wavelenflfl multiplexin (WDM) capabilities, tohanA5 these ITER multiplexin issues. We propose anA anAN2 data lin design for low-banjxF0N sennj an actuators basedon commercialo #-the-shelf (COTS) fiber optic compon5 ts. We relyon passive compon0 ts such as WDM couplersan fibre Bragggratin2 (FBG) to build a radiationfl0#NxnN t an5#j datalin0 WDM couplers remain operationx up to a 13 MGy gamma total dose. Aradiation53AxnA chan#/ drift is observed. The refractive inflNN han3 un33 ion33jj radiation is proposed as the degradation mechan30j FBG filters con tin ue to operate satisfactorily up to a 150 MGy total gamma dosean an505/3 fluen2 of about 10 15nx0 2 . Our resultson these COTS all-fibre passive compon5 ts open perspectives to build a radiation#A2/xn t an/5/ optical data lin compatible with the ITERrequiremen ts.

  8. China To Build Its Own Fusion Reactor ENERGY TECH

    E-Print Network [OSTI]

    Thermonuclear Experimental Reactor project reached agreement in Moscow Tuesday to construct the first fusion devices in thermonuclear reaction," and that "Chinese scientists started to develop a fusion operationChina To Build Its Own Fusion Reactor ENERGY TECH by Edward Lanfranco Beijing (UPI) July 1, 2005

  9. Method and system to directly produce electrical power within the lithium blanket region of a magnetically confined, deuterium-tritium (DT) fueled, thermonuclear fusion reactor

    DOE Patents [OSTI]

    Woolley, Robert D. (Belle Mead, NJ)

    1999-01-01T23:59:59.000Z

    A method for integrating liquid metal magnetohydrodynamic power generation with fusion blanket technology to produce electrical power from a thermonuclear fusion reactor located within a confining magnetic field and within a toroidal structure. A hot liquid metal flows from a liquid metal blanket region into a pump duct of an electromagnetic pump which moves the liquid metal to a mixer where a gas of predetermined pressure is mixed with the pressurized liquid metal to form a Froth mixture. Electrical power is generated by flowing the Froth mixture between electrodes in a generator duct. When the Froth mixture exits the generator the gas is separated from the liquid metal and both are recycled.

  10. Thermonuclear Supernovae

    E-Print Network [OSTI]

    F. K. Roepke

    2008-04-14T23:59:59.000Z

    The application of Type Ia supernovae (SNe Ia) as distance indicators in cosmology calls for a sound understanding of these objects. Recent years have seen a brisk development of astrophysical models which explain SNe Ia as thermonuclear explosions of white dwarf stars. While the evolution of the progenitor is still uncertain, the explosion mechanism certainly involves the propagation of a thermonuclear flame through the white dwarf star. Three-dimensional hydrodynamical simulations allowed to study a wide variety of possibilities involving subsonic flame propagation (deflagrations), flames accelerated by turbulence, and supersonic detonations. These possibilities lead to a variety of scenarios. I review the currently discussed approaches and present some recent results from simulations of the turbulent deflagration model and the delayed detonation model.

  11. How far is a Fusion Power Reactor from an Experimental Reactor?

    E-Print Network [OSTI]

    1 How far is a Fusion Power Reactor from an Experimental Reactor? R. Toschi(1) , P. Barabaschi(2 September 2000 Madrid, Spain #12;2 How far is a fusion power reactor from an experimental reactor? R. Toschi To support a request of very substantial resources to build and operate an experimental reactor such as ITER

  12. acid immunoaffinity reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    sludge blanket reactors (more) Ning, Zuojun. 2009-01-01 8 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  13. ASTROPHYSICAL THERMONUCLEAR FUNCTIONS

    E-Print Network [OSTI]

    W. J. Anderson; H. J. Haubold; A. M. Mathai

    1993-01-01T23:59:59.000Z

    approaches have been made to derive closed-form representations of thermonuclear reaction rates (Critchfield

  14. Physics modeling support for the International Thermonuclear Experimental Reactor: Final report

    SciTech Connect (OSTI)

    Not Available

    1988-09-30T23:59:59.000Z

    There are two major sections to this report. The first section of the report is an executive summary of the work done this year. For each task, the major results are condensed for the reader's convenience. The major result of each memo, report or presentation is summarized briefly in this section. The second section of the report is a collection of appendices containing reports, memos, and presentations written this year. Here, the interested reader can investigate any topic discussed in the summary in more detail. The documentation is presented in chronological order, and we would like to note that the content of later documents may supercede that of earlier ones. The summaries are divided into sections, corresponding to the tasks outlined in the original proposal for the work. These sections are: MUMAK code development and application; Alfven wave stability problem; TETRA systems code development and application; lower hybrid heating and current drive; and advanced blanket modeling.

  15. ITER vacuum vessel fabrication plan and cost study (D 68) for the international thermonuclear experimental reactor

    SciTech Connect (OSTI)

    NONE

    1995-01-01T23:59:59.000Z

    ITER Task No. 8, Vacuum Vessel Fabrication Plan and Cost Study (D68), was initiated to assess ITER vacuum vessel fabrication, assembly, and cost. The industrial team of Raytheon Engineers & Constructors and Chicago Bridge & Iron (Raytheon/CB&I) reviewed the current vessel basis and prepared a manufacturing plan, assembly plan, and cost estimate commensurate with the present design. The guidance for the Raytheon/CB&I assessment activities was prepared by the ITER Garching Work Site. This guidance provided in the form of work descriptions, sketches, drawings, and costing guidelines for each of the presently identified vacuum vessel Work Breakdown Structure (WBS) elements was compiled in ITER Garching Joint Work Site Memo (Draft No. 9 - G 15 MD 01 94-17-05 W 1). A copy of this document is provided as Appendix 1 to this report. Additional information and clarifications required for the Raytheon/CB&I assessments were coordinated through the US Home Team (USHT) and its technical representative. Design details considered essential to the Task 8 assessments but not available from the ITER Joint Central Team (JCT) were generated by Raytheon/CB&I and documented accordingly.

  16. Progress in preparing scenarios for operation of the International Thermonuclear Experimental Reactor

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sips, A. C. C.; Giruzzi, G.; Ide, S.; Kessel, C.; Luce, T. C.; Snipes, J. A.; Stober, J. K.

    2015-02-01T23:59:59.000Z

    The development of operating scenarios is one of the key issues in the research for ITER which aims to achieve a fusion gain (Q) of ~10, while producing 500MW of fusion power for ?300 s. The ITER Research plan proposes a success oriented schedule starting in hydrogen and helium, to be followed by a nuclear operation phase with a rapid development towards Q ~ 10 in deuterium/tritium. The Integrated Operation Scenarios Topical Group of the International Tokamak Physics Activity initiates joint activities among worldwide institutions and experiments to prepare ITER operation. Plasma formation studies report robust plasma breakdown in devicesmore »with metal walls over a wide range of conditions, while other experiments use an inclined EC launch angle at plasma formation to mimic the conditions in ITER. Simulations of the plasma burn-through predict that at least 4MW of Electron Cyclotron heating (EC) assist would be required in ITER. For H-modes at q??~ 3, many experiments have demonstrated operation with scaled parameters for the ITER baseline scenario at ne/nGW ~ 0.85. Most experiments, however, obtain stable discharges at H??(y,2) ~ 1.0 only for bN = 2.0–2.2. For the rampup in ITER, early X-point formation is recommended, allowing auxiliary heating to reduce the flux consumption. A range of plasma inductance (li(3)) can be obtained from 0.65 to 1.0, with the lowest values obtained in H-mode operation. For the rampdown, the plasma should stay diverted maintaining H-mode together with a reduction of the elongation from 1.85 to 1.4. Simulations show that the proposed rampup and rampdown schemes developed since 2007 are compatible with the present ITER design for the poloidal field coils. At 13–15 MA and densities down to ne/nGW ~ 0.5, long pulse operation (>1000 s) in ITER is possible at Q ~ 5, useful to provide neutron fluence for Test Blanket Module assessments. ITER scenario preparation in hydrogen and helium requires high input power (>50 MW). H-mode operation in helium may be possible at input powers above 35MW at a toroidal field of 2.65T, for studying H-modes and ELM mitigation. In hydrogen, H-mode operation is expected to be marginal, even at 2.65T with 60MW of input power. Simulation code benchmark studies using hybrid and steady state scenario parameters have proved to be a very challenging and lengthy task of testing suites of codes, consisting of tens of sophisticated modules. Nevertheless, the general basis of the modelling appears sound, with substantial consistency among codes developed by different groups. For a hybrid scenario at 12 MA, the code simulations give a range for Q = 6.5–8.3, using 30MW neutral beam injection and 20MW ICRH. For non-inductive operation at 7–9 MA, the simulation results show more variation. At high edge pedestal pressure (Tped ~ 7 keV), the codes predict Q = 3.3–3.8 using 33MW NB, 20MW EC, and 20MW ion cyclotron to demonstrate the feasibility of steady-state operation with the day-1 heating systems in ITER. Simulations using a lower edge pedestal temperature (~3 keV) but improved core confinement obtain Q = 5–6.5, when ECCD is concentrated at mid-radius and ~ 20MW off-axis current drive (ECCD or LHCD) is added. Several issues remain to be studied, including plasmas with dominant electron heating, mitigation of transient heat loads integrated in scenario demonstrations and (burn) control simulations in ITER scenarios.« less

  17. Experimental and Computational Study of Fluid Dynamics in Solar Reactor

    E-Print Network [OSTI]

    Chien, Min-Hsiu

    2014-02-19T23:59:59.000Z

    The experimental simulation and a computational validation of a methane-cracking solar reactor powered by solar energy is the focus of this article. A solar cyclone reactor operates at over 1000 °C where the methane decomposition reaction takes...

  18. Elastic-plastic analysis of the transition divertor joint for high performance divertor target plate

    E-Print Network [OSTI]

    Navaei, Dara

    2011-01-01T23:59:59.000Z

    CER) 8. International Thermonuclear Experimental Reactor (to International Thermonuclear Experimental Reactor (International Thermonuclear Experimental Reactor (ITER) is a

  19. ardennes reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    d'un parasite cycle Paris-Sud XI, Universit de 12 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  20. aprf reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of the specimen. The sensitivity Paris-Sud XI, Universit de 6 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  1. a-2 reactor bohunice: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Barbara Ricci; Virginia Strati; Gerti Xhixha 2014-11-24 7 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  2. a-1 reactor bohunice: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of degree one rather than rational points. Nguyen Le Dang Thi 7 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  3. Experimental measurements of the O15(alpha,gamma)Ne19 reaction rate and the stability of thermonuclear burning on accreting neutron stars

    E-Print Network [OSTI]

    Jacob Lund Fisker; Wanpeng Tan; Joachim Goerres; Michael Wiescher; Randall L. Cooper

    2007-05-07T23:59:59.000Z

    Neutron stars in close binary star systems often accrete matter from their companion stars. Thermonuclear ignition of the accreted material in the atmosphere of the neutron star leads to a thermonuclear explosion which is observed as an X-ray burst occurring periodically between hours and days depending on the accretion rate. The ignition conditions are characterized by a sensitive interplay between the accretion rate of the fuel supply and its depletion rate by nuclear burning in the hot CNO cycle and the rp-process. For accretion rates close to stable burning the burst ignition therefore depends critically on the hot CNO breakout reaction, O15(alpha,gamma)Ne19, that regulates the flow between the hot CNO cycle and the rapid proton capture process. Until recently, the O15(alpha,gamma)Ne19-reaction rate was not known experimentally and the theoretical estimates carried significant uncertainties. In this paper we perform a parameter study of the uncertainty of this reaction rate and determine the astrophysical consequences of the first measurement of this reaction rate. Our results corroborate earlier predictions and show that theoretically burning remains unstable up to accretion rates near the Eddington limit, in contrast to astronomical observations.

  4. Experimental Measurements of Fluence Distribution in a UV Reactor

    E-Print Network [OSTI]

    Bohrer, Gil

    Experimental Measurements of Fluence Distribution in a UV Reactor Using Fluorescent Microspheres Z Carolina State University, Raleigh, North Carolina 27695 One concern with current techniques of UV reactor distribution of a UV reactor is measured through the use of photo- chemically active fluorescent microspheres

  5. Japan Denies Report It Dropped Proposal to Host Fusion Reactor

    E-Print Network [OSTI]

    Print Japan Denies Report It Dropped Proposal to Host Fusion Reactor June 22 (Bloomberg) -- Japan fusion reactor, a decision that would end a standoff with France to site the 4.6 billion-euro ($5 the International Thermonuclear Experimental Reactor in return for assurances it will manage the project in France

  6. astrophysical thermonuclear reactions: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    well as experimental investigations are motivated. T. Rauscher 1998-10-15 4 Astrophysical thermonuclear functions Astrophysics (arXiv) Summary: Stars are gravitationally stabilized...

  7. Thermonuclear Fusion Energy : Assessment and Next Step Ren Pellat

    E-Print Network [OSTI]

    Thermonuclear Fusion Energy : Assessment and Next Step René Pellat High Commissioner at the French 2000, Rome Abstract Fifty years of thermonuclear fusion work with no insurmountable road blocks have allowed to continuously progress towards the fusion reactor which stays a physics and technology ambitious

  8. Simplest AB-Thermonuclear Space Propulsion and Electric Generator

    E-Print Network [OSTI]

    Alexander Bolonkin

    2007-01-19T23:59:59.000Z

    The author applies, develops and researches mini-sized Micro- AB Thermonuclear Reactors for space propulsion and space power systems. These small engines directly convert the high speed charged particles produced in the thermonuclear reactor into vehicle thrust or vehicle electricity with maximum efficiency. The simplest AB-thermonuclear propulsion offered allows spaceships to reach speeds of 20,000 50,000 km/s (1/6 of light speed) for fuel ratio 0.1 and produces a huge amount of useful electric energy. Offered propulsion system permits flight to any planet of our Solar system in short time and to the nearest non-Sun stars by E-being or intellectual robots during a single human life period. Key words: AB-propulsion, thermonuclear propulsion, space propulsion, thermonuclear power system.

  9. Space power reactor ground test in the Experimental Gas Cooled Reactor (EGCR) at Oak Ridge

    SciTech Connect (OSTI)

    Fontana, M.H.; Holcomb, R.S.; Cooper, R.H.

    1992-08-01T23:59:59.000Z

    The Experimental Gas Cooled Reactor (EGCR) facility and the supporting technical infrastructure at the Oak Ridge National Laboratory have the capabilities of performing ground tests of space nuclear power reactor systems. A candidate test would be a 10 MWt lithium cooled reactor, generating potassium vapor that would drive a power turbine. The facility is a large containment vessel originally intended to test the EGCR. Large, contained, and shielded spaces are available for testing, assembly, disassembly, and post-test examination.

  10. June 28, 2005 France to Be Site of World's First Nuclear Fusion Reactor

    E-Print Network [OSTI]

    June 28, 2005 France to Be Site of World's First Nuclear Fusion Reactor By CRAIG S. SMITH PARIS fusion reactor, an estimated $12 billion project that many scientists see as essential to solving chose the country as the site for the International Thermonuclear Experimental Reactor. Japan, which had

  11. | |SAVE THIS EMAIL THIS Close Japan ups bid for fusion reactor site

    E-Print Network [OSTI]

    Powered by | |SAVE THIS EMAIL THIS Close Japan ups bid for fusion reactor site TOKYO, Japan (AP billion if the project's sponsors build the reactor in Japan, a newspaper reported Wednesday. Construction of the U.S. $12 billion International Thermonuclear Experimental Reactor, or ITER, which would run

  12. Macroscopic implications from phase space dynamics of tokamak turbulence : relaxation, transport, and flow generation

    E-Print Network [OSTI]

    Kosuga, Yusuke

    2012-01-01T23:59:59.000Z

    for the International Thermonuclear Experimental Reactor (for the International Thermonuclear Experimental Reactor (

  13. anaerobic hybrid reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    required for thermonuclear reactors R@frascati.enea.it Abstract. For the progress of the thermonuclear fusion energy research based on the tokamak concept in ITER (International...

  14. Nucleosynthesis in Thermonuclear Supernovae

    SciTech Connect (OSTI)

    Claudia, Travaglio [Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Torino; Hix, William Raphael [ORNL

    2013-01-01T23:59:59.000Z

    We review our understanding of the nucleosynthesis that occurs in thermonuclear supernovae and their contribution to Galactic Chemical evolution. We discuss the prospects to improve the modeling of the nucleosynthesis within simulations of these events.

  15. Fusion reactor control

    SciTech Connect (OSTI)

    Plummer, D.A.

    1995-12-31T23:59:59.000Z

    The plasma kinetic temperature and density changes, each per an injected fuel density rate increment, control the energy supplied by a thermonuclear fusion reactor in a power production cycle. This could include simultaneously coupled control objectives for plasma current, horizontal and vertical position, shape and burn control. The minimum number of measurements required, use of indirect (not plasma parameters) system measurements, and distributed control procedures for burn control are to be verifiable in a time dependent systems code. The International Thermonuclear Experimental Reactor (ITER) has the need to feedback control both the fusion output power and the driven plasma current, while avoiding damage to diverter plates. The system engineering of fusion reactors must be performed to assure their development expeditiously and effectively by considering reliability, availability, maintainability, environmental impact, health and safety, and cost.

  16. Prediction of Thermonuclear Reaction Rates in Astrophysics

    E-Print Network [OSTI]

    T. Rauscher

    1998-10-15T23:59:59.000Z

    Recent improvements and remaining problems in the prediction of thermonuclear rates are reviewed. The main emphasis is on statistical model calculations, but the challenge to include direct reactions close to the driplines is also briefly addressed. Further theoretical as well as experimental investigations are motivated.

  17. Thermonuclear Ignition of Dark Galaxies

    E-Print Network [OSTI]

    J. Marvin Herndon

    2006-01-01T23:59:59.000Z

    thermonuclear ignition of stars by nuclear fission, and the corollary, non-ignition of stars. The possibility of

  18. Incipient Transient Detection in Reactor Systems: Experimental and Theoretical Investigation

    SciTech Connect (OSTI)

    Lefteri H. Tsoukalas; S.T. Revankar; X Wang; R. Sattuluri

    2005-09-27T23:59:59.000Z

    The main goal of this research was to develop a method for detecting reactor system transients at the earliest possible time through a comprehensive experimental, testing and benchmarking program. This approach holds strong promise for developing new diagnostic technologies that are non-intrusive, generic and highly portable across different systems. It will help in the design of new generation nuclear power reactors, which utilize passive safety systems with a reliable and non-intrusive multiphase flow diagnostic system to monitor the function of the passive safety systems. The main objective of this research was to develop an improved fuzzy logic based detection method based on a comprehensive experimental testing program to detect reactor transients at the earliest possible time, practically at their birth moment. A fuzzy logic and neural network based transient identification methodology and implemented in a computer code called PROTREN was considered in this research and was compared with SPRT (Sequentially Probability Ratio Testing) decision and Bayesian inference. The project involved experiment, theoretical modeling and a thermal-hydraulic code assessment. It involved graduate and undergraduate students participation providing them with exposure and training in advanced reactor concepts and safety systems. In this final report, main tasks performed during the project period are summarized and the selected results are presented. Detailed descriptions for the tasks and the results are presented in previous yearly reports (Revankar et al 2003 and Revankar et al 2004).

  19. A high-speed beam of lithium droplets for collecting diverted energy and particles in ITER (International Thermonuclear Experimental Reactor)

    SciTech Connect (OSTI)

    Werley, K.A.

    1989-01-01T23:59:59.000Z

    A high-speed (160m/s) beam (0.14 {times} 0.86m) of liquid-lithium droplets passing through the divertor region(s) below (and above) the main plasma has the potential to replace and out-perform conventional'' solid divertor plates in both heat and particle removal. In addition to superior heat-collection properties, the lithium beam would: remove impurities; require low power to circulate the lithium; exhibit low-recycle divertor operation compatible with lower-hybrid current drive, H-mode plasma confinement, and no flow reversal in the edge plasma; be insensitive to plasma shifts; and finally protect solid structures from the plasma thermal energy for those disruptions that deposit energy preferentially into the divertor while simultaneously being rapidly re-established after a major disruption. Scoping calculations identifying the beam configuration and the droplet dynamics, including formation, MHD effects, gravitational effects, thermal response and hydrodynamics, are presented. Limitations and uncertainties are also discussed. 20 refs., 6 figs., 3 tabs.

  20. A Study of Reactor Neutrino Monitoring at Experimental Fast Reactor JOYO

    E-Print Network [OSTI]

    Furuta, H; Hara, T; Haruna, T; Ishihara, N; Ishitsuka, M; Ito, C; Katsumata, M; Kawasaki, T; Konno, T; Kuze, M; Maeda, J; Matsubara, T; Miyata, H; Nagasaka, Y; Nitta, K; Sakamoto, Y; Suekane, F; Sumiyoshi, T; Tabata, H; Takamatsu, M; Tamura, N

    2011-01-01T23:59:59.000Z

    We carried out a study of neutrino detection at the experimental fast reactor JOYO using a 0.76 tons gadolinium loaded liquid scintillator detector. The detector was set up on the ground level at 24.3m from the JOYO reactor core of 140MW thermal power. The measured neutrino event rate from reactor on-off comparison was 1.11\\pm1.24(stat.)\\pm0.46(syst.)events/day. Although the statistical significance of the measurement was not enough, the background in such a compact detector at the ground level was studied in detail and MC simulation was found to describe the data well. A study for improvement of the detector for future such experiments is also shown.

  1. A Study of Reactor Neutrino Monitoring at Experimental Fast Reactor JOYO

    E-Print Network [OSTI]

    H. Furuta; Y. Fukuda; T. Hara; T. Haruna; N. Ishihara; M. Ishitsuka; C. Ito; M. Katsumata; T. Kawasaki; T. Konno; M. Kuze; J. Maeda; T. Matsubara; H. Miyata; Y. Nagasaka; K. Nitta; Y. Sakamoto; F. Suekane; T. Sumiyoshi; H. Tabata; M. Takamatsu; N. Tamura

    2011-08-14T23:59:59.000Z

    We carried out a study of neutrino detection at the experimental fast reactor JOYO using a 0.76 tons gadolinium loaded liquid scintillator detector. The detector was set up on the ground level at 24.3m from the JOYO reactor core of 140MW thermal power. The measured neutrino event rate from reactor on-off comparison was 1.11\\pm1.24(stat.)\\pm0.46(syst.)events/day. Although the statistical significance of the measurement was not enough, the background in such a compact detector at the ground level was studied in detail and MC simulation was found to describe the data well. A study for improvement of the detector for future such experiments is also shown.

  2. Selective hydrogenation in trickle-bed reactor. Experimental and modelling including partial wetting.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    reactor; selective hydrogenation; trickle-bed modelling. 1. Introduction Fixed-bed reactors with down1/12 Selective hydrogenation in trickle-bed reactor. Experimental and modelling including partial / ENSIACET 118 route de Narbonne 31077 TOULOUSE cedex Abstract A steady state model of a trickle bed reactor

  3. atucha-2 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  4. atucha-1 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  5. acpr reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  6. atlantic-1 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 6 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  7. arbus reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  8. akm reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 9 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  9. argonaut reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 14 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  10. argonaut lemont reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 15 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  11. arkansas-2 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  12. apra reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 7 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  13. apsara reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 6 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  14. asco-1 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  15. atlantic-2 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  16. akr-1 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 6 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  17. akm muehleberg reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 9 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  18. arsi reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 12 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  19. aipfr reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  20. asco-2 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  1. argonauta rien-1 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 6 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  2. ahfr reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  3. almaraz-2 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  4. aarr reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  5. almaraz-1 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  6. arkansas-1 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 6 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  7. akw1 rheinsberg reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 6 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  8. aguirre-1 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 11 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  9. arbi reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 7 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  10. agesta reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  11. acrr reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  12. affri reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  13. afsr reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  14. atsr reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 7 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  15. alrr reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 6 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  16. Ceramic breeder blanket development for fusion experimental reactor in JAERI

    SciTech Connect (OSTI)

    Kurasawa, T.; Takatsu, H.; Sato, S. [JAERI, Ibaraki-ken (Japan)] [and others

    1994-12-31T23:59:59.000Z

    Ceramic breeding blanket is a promising breeding blanket concept for the fusion experimental reactor, and world-wide efforts have been devoted to the design and R&D. Irradiation damages of both of breeding materials and neutron multipliers are one of the critical issues for this type of blanket, and usage of these materials as a form of small pebbles has been proposed so as to accommodate expected irradiation damages without degradation of breeding capability. The present paper outlines the progress of the design of layered pebble bed breeding blanket and also shows preliminary results of concept development related to higher fusion power accommodation and convertible blanket.

  17. Experimental Breeder Reactor-II Primary Tank System Wash Water Workshop

    Broader source: Energy.gov [DOE]

    In 1994 Congress ordered the shutdown of the Experimental Breeder Reactor-II (EBR-II) and a closure project was initiated.

  18. Implications of Thermonuclear-Fusion Energy Systems

    E-Print Network [OSTI]

    André Gsponer; Jean-pierre Hurni

    2004-01-01T23:59:59.000Z

    militarytechnical reasons and implications of the very probable siting of ITER (the International Thermonuclear

  19. Electron Screening Effect on Stellar Thermonuclear Fusion

    E-Print Network [OSTI]

    K. -h. Spatschek; M. Bonitz; T. Klinger; U. Ebert; C. Franck; A. V. Keudell; D. Naujoks; M. Dewitz; A. Y. Potekhin; G. Chabrier

    2012-01-01T23:59:59.000Z

    thermonuclear fusions and show that these scenarios do not apply to stellar conditions. c ? 2013 WILEY

  20. Programmable AC power supply for simulating power transient expected in fusion reactor

    SciTech Connect (OSTI)

    Halimi, B. [Seoul National Univ., Seoul 151-744 (Korea, Republic of); Suh, K. Y. [Seoul National Univ., Seoul 151-744 (Korea, Republic of); PHILOSOPHIA, 1 Gwanak Ro, Gwanak Gu, Seoul 151-744 (Korea, Republic of)

    2012-07-01T23:59:59.000Z

    This paper focus on control engineering of the programmable AC power source which has capability to simulate power transient expected in fusion reactor. To generate the programmable power source, AC-AC power electronics converter is adopted to control the power of a set of heaters to represent the transient phenomena of heat exchangers or heat sources of a fusion reactor. The International Thermonuclear Experimental Reactor (ITER) plasma operation scenario is used as the basic reference for producing this transient power source. (authors)

  1. Simulation-Based Design and Experimental Evaluation of a Spatially Controllable CVD Reactor

    E-Print Network [OSTI]

    Rubloff, Gary W.

    Simulation-Based Design and Experimental Evaluation of a Spatially Controllable CVD Reactor Jae CVD reactor system has been developed that can explicitly control the spatial profile of gas, opening the door to a new class of flexible and highly controllable CVD reactor designs. © 2005 American

  2. Removal of volatile organic compounds from polluted air in a reverse flow reactor: An experimental study

    SciTech Connect (OSTI)

    Beld, B. van de; Borman, R.A.; Derkx, O.R.; Woezik, B.A.A. van; Westerterp, K.R. (Univ. of Twente, Enschede (Netherlands). Dept. of Chemical Engineering)

    1994-12-01T23:59:59.000Z

    An experimental study of the reverse flow reactor for the purification of contaminated air has been carried out. An experimental reactor with an inner diameter of 0.145 m has been constructed. It almost completely reached the goal of an adiabatically operating system. The influence of several operating parameters such as gas velocity, cycle period, chemical character, and concentration of the pollutants and reactor pressure are discussed. The reactor could be operated autothermally provided that the inlet concentrations were sufficiently high. If a mixture of contaminants is fed to the reactor, it might be necessary to increase the total hydrocarbon concentration to assure an autothermal process. Increasing the reactor pressure will hardly change the axial temperature profiles, if the mass flux is kept constant. Increasing the mass flow rate will lead to a higher plateau temperature. Not only the reactor behavior at fixed operating conditions, but also the response of the reactor toward variations in inlet conditions is reported.

  3. advanced passive reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Thomas 2006-01-01 12 Radiation Hardness of Passive Fibre Optic Components for the Future Thermonuclear Fusion Reactor CiteSeer Summary: thermon uclearfusion reactor ITER will...

  4. Decommissioning of Experimental Breeder Reactor - II Complex, Post Sodium Draining

    SciTech Connect (OSTI)

    J. A. (Bart) Michelbacher; S. Paul Henslee; Collin J. Knight; Steven R. sherman

    2005-09-01T23:59:59.000Z

    The Experimental Breeder Reactor - II (EBR-II) was shutdown in September 1994 as mandated by the United States Department of Energy. This sodium-cooled reactor had been in service since 1964. The bulk sodium was drained from the primary and secondary systems and processed. Residual sodium remaining in the systems after draining was converted into sodium bicarbonate using humid carbon dioxide. This technique was tested at Argonne National Laboratory in Illinois under controlled conditions, then demonstrated on a larger scale by treating residual sodium within the EBR-II secondary cooling system, followed by the primary tank. This process, terminated in 2002, was used to place a layer of sodium bicarbonate over all exposed surfaces of sodium. Treatment of the remaining EBR-II sodium is governed by the Resource Conservation and Recovery Act (RCRA). The Idaho Department of Environmental Quality issued a RCRA Operating Permit in 2002, mandating that all hazardous materials be removed from EBR-II within a 10 year period, with the ability to extend the permit and treatment period for another 10 years. A preliminary plan has been formulated to remove the remaining sodium and NaK from the primary and secondary systems using moist carbon dioxide, steam and nitrogen, and a water flush. The moist carbon dioxide treatment was resumed in May 2004. As of August 2005, approximately 60% of the residual sodium within the EBR-II primary tank had been treated. This process will continue through the end of 2005, when it is forecast that the process will become increasingly ineffective. At that time, subsequent treatment processes will be planned and initiated. It should be noted that the processes and anticipated costs associated with these processes are preliminary. Detailed engineering has not been performed, and approval for these methods has not been obtained from the regulator or the sponsors.

  5. aeg-pr-10 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  6. ao-phai-1 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  7. alma-ata wwr-k reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  8. are-rr-1 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  9. ai-l-77 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  10. airos-2a space-independent reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 6 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  11. adsorbent-membrane reactor hamr: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 10 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  12. agesta-r3 reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  13. almaty wwr-k reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the flux calculation and recent progresses. Jun Cao 2012-03-08 5 Inexpensive Mini Thermonuclear Reactor CiteSeer Summary: This proposed design for a mini thermonuclear reactor...

  14. COMPUTATIONAL AND EXPERIMENTAL MODELING OF SLURRY BUBBLE COLUMN REACTORS

    SciTech Connect (OSTI)

    Paul Lam; Dimitri Gidaspow

    2001-08-01T23:59:59.000Z

    This project is a collaborative effort between the University of Akron, Illinois Institute of Technology and two industries: UOP and Energy International. The tasks involve the development of transient two and three dimensional computer codes for slurry bubble column reactors, optimization, comparison to data, and measurement of input parameters, such as the viscosity and restitution coefficients. To understand turbulence, measurements were done in the riser with 530 micron glass beads using a PIV technique. This report summarizes the measurements and simulations completed as described in details in the attached paper, ''Computational and Experimental Modeling of Three-Phase Slurry-Bubble Column Reactor.'' The Particle Image Velocimetry method described elsewhere (Gidaspow and Huilin, 1996) was used to measure the axial and tangential velocities of the particles. This method was modified with the use of a rotating colored transparent disk. The velocity distributions obtained with this method shows that the distribution is close to Maxwellian. From the velocity measurements the normal and the shear stresses were computed. Also with the use of the CCD camera a technique was developed to measure the solids volume fraction. The granular temperature profile follows the solids volume fraction profile. As predicted by theory, the granular temperature is highest at the center of the tube. The normal stress in the direction of the flow is approximately 10 times larger than that in the tangential direction. The <{nu}{prime}{sub z}{nu}{prime}{sub z}> is lower at the center where the <{nu}{prime}{sub {theta}}{nu}{prime}{sub {theta}}> is higher at that point. The Reynolds shear stress was small, producing a restitution coefficient near unity. The normal Reynolds stress in the direction of flow is large due to the fact that it is produced by the large gradient of velocity in the direction of flow compared to the small gradient in the {theta} and r directions. The kinetic theory gives values of viscosity that agree with our previous measurements (Gidaspow, Wu and Mostofi, 1999). The values of viscosity obtained from pressure drop minus weight of bed measurements agree at the center of the tube.

  15. Measurement of neutron capture on $^{48}$Ca at thermal and thermonuclear energies

    E-Print Network [OSTI]

    H. Beer; C. Coceva; P. V. Sedyshev; Yu. P. Popov; H. Herndl; R. Hofinger; P. Mohr; H. Oberhummer

    1996-08-07T23:59:59.000Z

    At the Karlsruhe pulsed 3.75\\,MV Van de Graaff accelerator the thermonuclear $^{48}$Ca(n,$\\gamma$)$^{49}$Ca(8.72\\,min) cross section was measured by the fast cyclic activation technique via the 3084.5\\,keV $\\gamma$-ray line of the $^{49}$Ca-decay. Samples of CaCO$_3$ enriched in $^{48}$Ca by 77.87\\,\\% were irradiated between two gold foils which served as capture standards. The capture cross-section was measured at the neutron energies 25, 151, 176, and 218\\,keV, respectively. Additionally, the thermal capture cross-section was measured at the reactor BR1 in Mol, Belgium, via the prompt and decay $\\gamma$-ray lines using the same target material. The $^{48}$Ca(n,$\\gamma$)$^{49}$Ca cross-section in the thermonuclear and thermal energy range has been calculated using the direct-capture model combined with folding potentials. The potential strengths are adjusted to the scattering length and the binding energies of the final states in $^{49}$Ca. The small coherent elastic cross section of $^{48}$Ca+n is explained through the nuclear Ramsauer effect. Spectroscopic factors of $^{49}$Ca have been extracted from the thermal capture cross-section with better accuracy than from a recent (d,p) experiment. Within the uncertainties both results are in agreement. The non-resonant thermal and thermonuclear experimental data for this reaction can be reproduced using the direct-capture model. A possible interference with a resonant contribution is discussed. The neutron spectroscopic factors of $^{49}$Ca determined from shell-model calculations are compared with the values extracted from the experimental cross sections for $^{48}$Ca(d,p)$^{49}$Ca and $^{48}$Ca(n,$\\gamma$)$^{49}$Ca.

  16. President Truman Orders Development of Thermonuclear Weapon ...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Orders Development of Thermonuclear Weapon | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile Preventing...

  17. Approaches to modeling thermonuclear flames

    E-Print Network [OSTI]

    J. C. Niemeyer; W. K. Bushe; G. R. Ruetsch

    Turbulence-flame interactions of thermonuclear fusion flames occurring in Type Ia Supernovae were studied by means of incompressible DNS with a highly simplified flame description. The flame is treated as a single diffusive scalar field with a nonlinear source term. It is characterized by its

  18. New Views of Thermonuclear Bursts

    E-Print Network [OSTI]

    Tod Strohmayer; Lars Bildsten

    2003-05-06T23:59:59.000Z

    Since the advent of powerful new X-ray observatories, NASA's Rossi X-ray Timing Explorer (RXTE), the Italian - Dutch BeppoSAX mission, XMM-Newton and Chandra, a number of entirely new phenomena associated with thermonuclear burning on neutron stars have been discovered. These include: (i) the discovery of millisecond (300 - 600 Hz) oscillations during bursts, so called ``burst oscillations'', (ii) a new regime of nuclear burning on neutron stars which manifests itself through the generation of hours long flares about once a decade, now referred to as ``superbursts'',(iii) discoveries of bursts from low accretion rate neutron stars, and (iv) new evidence for discrete spectral features from bursting neutron stars. In this article we review our current understanding of thermonuclear bursts on neutron stars, with a focus on these new phenomena.

  19. Thermonuclear Ignition of Dark Galaxies

    E-Print Network [OSTI]

    J. Marvin Herndon

    2006-04-13T23:59:59.000Z

    Dark matter is thought to be at least an order of magnitude more abundant than luminous matter in the Universe, but there has yet to be an unambiguous identification of a wholly dark, galactic-scale structure. There is, however, increasing evidence that VIRGOHI 21 may be a dark galaxy. If VIRGOHI 21 turns out to be composed of dark stars, having approximately the same mass of stars found in luminous galaxies, it will pose an enigma within the framework of current astrophysical models, but will provide strong support for my concept, published in 1994 in the Proceedings of the Royal Society of London, of the thermonuclear ignition of stars by nuclear fission, and the corollary, non-ignition of stars. The possibility of galactic thermonuclear ignition is discussed from that framework and leads to my suggestion that the distribution of luminous stars in a galaxy may simply be a reflection of the galactic distribution of the heavy elements.

  20. Experimental Highlights - 2014

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    weapons as they age or are subjected to the immense pressures and temperatures of a thermonuclear explosion. By providing experimental data to compare to computer models of...

  1. 4/20/14 12:35 PMSenators Request GAO Investigation of Costs at Experimental Fusion React...tems -Newsroom -U.S. Senate Committee on Energy and Natural Resources Page 1 of 2http://www.energy.senate.gov/public/index.cfm/featured-items?ID=854ad0a0-fe2a-4a04-

    E-Print Network [OSTI]

    Thermonuclear Experimental Reactor and its effect on U.S. fusion programs. Senators Ron Wyden, D-Ore., Lisa4/20/14 12:35 PMSenators Request GAO Investigation of Costs at Experimental Fusion React.S. fusion energy science programs and user facilities have, and may continue to be, cut to pay

  2. aerospace system test reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    methods of nulcear fusion: inertial confinement fusion (ICF) and magnetic confinement fusion (MCF). Existing thermonuclear reactors are very complex, expensive, large, and...

  3. anuclear research reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    methods of nulcear fusion: inertial confinement fusion (ICF) and magnetic confinement fusion (MCF). Existing thermonuclear reactors are very complex, expensive, large, and...

  4. atypical thermonuclear supernovae: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Websites Summary: White dwarf mergers,White dwarf mergers, thermonuclear supernovae,thermonuclear supernovae fusion is ignited. Degenerate, hence runaway. 12;CO white dwarf...

  5. Workshop on Thermonuclear Reaction Rates for Astrophysics Applications

    E-Print Network [OSTI]

    Workshop on Thermonuclear Reaction Rates for Astrophysics Applications 24-25 November 2011, Athensrd and final circular for the Workshop on Thermonuclear Reaction Rates for Astrophysics Applications

  6. Experimental Studies of NGNP Reactor Cavity Cooling System With Water

    SciTech Connect (OSTI)

    Corradini, Michael; Anderson, Mark; Hassan, Yassin; Tokuhiro, Akira

    2013-01-16T23:59:59.000Z

    This project will investigate the flow behavior that can occur in the reactor cavity cooling system (RCCS) with water coolant under the passive cooling-mode of operation. The team will conduct separate-effects tests and develop associated scaling analyses, and provide system-level phenomenological and computational models that describe key flow phenomena during RCCS operation, from forced to natural circulation, single-phase flow and two-phase flow and flashing. The project consists of the following tasks: Task 1. Conduct separate-effects, single-phase flow experiments and develop scaling analyses for comparison to system-level computational modeling for the RCCS standpipe design. A transition from forced to natural convection cooling occurs in the standpipe under accident conditions. These tests will measure global flow behavior and local flow velocities, as well as develop instrumentation for use in larger scale tests, thereby providing proper flow distribution among standpipes for decay heat removal. Task 2. Conduct separate-effects experiments for the RCCS standpipe design as two-phase flashing occurs and flow develops. As natural circulation cooling continues without an ultimate heat sink, water within the system will heat to temperatures approaching saturation , at which point two-phase flashing and flow will begin. The focus is to develop a phenomenological model from these tests that will describe the flashing and flow stability phenomena. In addition, one could determine the efficiency of phase separation in the RCCS storage tank as the two-phase flashing phenomena ensues and the storage tank vents the steam produced. Task 3. Develop a system-level computational model that will describe the overall RCCS behavior as it transitions from forced flow to natural circulation and eventual two-phase flow in the passive cooling-mode of operation. This modeling can then be used to test the phenomenological models developed as a function of scale.

  7. Toward the Development of Radiation-Tolerant Instrumentation Data Links for Thermonuclear Fusion Experiments

    E-Print Network [OSTI]

    Alberto Fernandez Fernandez; Ez Fern; F. Berghmans; B. Brichard; M. Decreton

    2002-01-01T23:59:59.000Z

    Thermonuclear reactors will require permanent monitoring under high-gamma dose rates and high neutron flux. We propose to get rid of the digital data transmission limitations in highly radioactive environments by implementing an analog fiber-optic link based on directly modulated vertical

  8. On thermonuclear ignition criterion at the National Ignition Facility

    SciTech Connect (OSTI)

    Cheng, Baolian; Kwan, Thomas J. T.; Wang, Yi-Ming; Batha, Steven H. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-10-15T23:59:59.000Z

    Sustained thermonuclear fusion at the National Ignition Facility remains elusive. Although recent experiments approached or exceeded the anticipated ignition thresholds, the nuclear performance of the laser-driven capsules was well below predictions in terms of energy and neutron production. Such discrepancies between expectations and reality motivate a reassessment of the physics of ignition. We have developed a predictive analytical model from fundamental physics principles. Based on the model, we obtained a general thermonuclear ignition criterion in terms of the areal density and temperature of the hot fuel. This newly derived ignition threshold and its alternative forms explicitly show the minimum requirements of the hot fuel pressure, mass, areal density, and burn fraction for achieving ignition. Comparison of our criterion with existing theories, simulations, and the experimental data shows that our ignition threshold is more stringent than those in the existing literature and that our results are consistent with the experiments.

  9. Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations

    E-Print Network [OSTI]

    Iliadis, Christian; Coc, Alain; Timmes, F X; Champagne, Art E

    2014-01-01T23:59:59.000Z

    Rigorous statistical methods for estimating thermonuclear reaction rates and nucleosynthesis are becoming increasingly established in nuclear astrophysics. The main challenge being faced is that experimental reaction rates are highly complex quantities derived from a multitude of different measured nuclear parameters (e.g., astrophysical S-factors, resonance energies and strengths, particle and gamma-ray partial widths). We discuss the application of the Monte Carlo method to two distinct, but related, questions. First, given a set of measured nuclear parameters, how can one best estimate the resulting thermonuclear reaction rates and associated uncertainties? Second, given a set of appropriate reaction rates, how can one best estimate the abundances from nucleosynthesis (i.e., reaction network) calculations? The techniques described here provide probability density functions that can be used to derive statistically meaningful reaction rates and final abundances for any desired coverage probability. Examples ...

  10. CO{sub 2} adsorption: Experimental investigation with kinetics verification and CFD reactor model validation

    SciTech Connect (OSTI)

    Breault, Ronald W, [U.S. DOE; Huckaby, Ernest D. [U.S. DOE; Shadle, Lawrence J [U.S. DOE; Spenik, James L. [REM Engineering PLLC

    2013-01-01T23:59:59.000Z

    The National Energy Technology Laboratory is investigating a new process for CO{sub 2} capture from large sources such as utility power generation facilities as an alternative to liquid amine based absorption processes. Many, but not all of these advanced dry processes are based upon sorbents composed of supported polyamines. In this analysis, experiments have been conducted in a small facility at different temperatures and compared to CFD reactor predictions using kinetics obtained from TGA tests. This particular investigation compares the predicted performance and the experimental performance of one of these new class of sorbents in a fluidized bed reactor. In the experiment, the sorbent absorbs CO{sub 2} from simulated flue gas in a riser reactor, separates the carbonated particles from the de-carbonated flue gas in a cyclone and then regenerates the sorbent, creating a concentrated stream of pure CO{sub 2} for sequestration. In this work, experimental measurements of adsorption are compared to predictions from a 3-dimensional non-isothermal reacting multiphase flow model. The effects of the gas flow rate and reactor temperature are explored. It is shown that the time duration for CO{sub 2} adsorption decreased for an increase in the gas flow. The details of the experimental facility and the model as well as the comparative analysis between the data and the simulation results are discussed.

  11. Thermonuclear burst physics with RXTE

    E-Print Network [OSTI]

    D. K. Galloway; D. Chakrabarty; A. Cumming; E. Kuulkers; L. Bildsten; R. Rothschild

    2004-04-22T23:59:59.000Z

    Recently we have made measurements of thermonuclear burst energetics and recurrence times which are unprecedented in their precision, largely thanks to the sensitivity of the Rossi X-ray Timing Explorer. In the "Clocked Burster", GS 1826-24, hydrogen burns during the burst via the rapid-proton (rp) process, which has received particular attention in recent years through theoretical and modelling studies. The burst energies and the measured variation of alpha (the ratio of persistent to burst flux) with accretion rate strongly suggests solar metallicity in the neutron star atmosphere, although this is not consistent with the corresponding variation of the recurrence time. Possible explanations include extra heating between the bursts, or a change in the fraction of the neutron star over which accretion takes place. I also present results from 4U 1746-37, which exhibits regular burst trains which are interrupted by "out of phase" bursts.

  12. Experimental study of Siphon breaker about size effect in real scale reactor design

    SciTech Connect (OSTI)

    Kang, S. H. [Mechanical Engineering Dept., POSTECH, Pohang, 790-784 (Korea, Republic of); Ahn, H. S. [Div. of Advanced Nuclear Engineering, POSTECH, Pohang, 790-784 (Korea, Republic of); Kim, J. M. [Mechanical Engineering Dept., POSTECH, Pohang, 790-784 (Korea, Republic of); Joo, H. M. [Dept. of Nuclear Engineering, Hanyang Univ., Seoul, 133-791 (Korea, Republic of); Lee, K. Y.; Seo, K.; Chi, D. Y. [KAERI, Yuseong, Daejeon, 305-353 (Korea, Republic of); Kim, M. H. [Div. of Advanced Nuclear Engineering, POSTECH, Pohang, 790-784 (Korea, Republic of)

    2012-07-01T23:59:59.000Z

    Rupture accident within the pipe of a nuclear reactor is one of the main causes of a loss of coolant accident (LOCA). Siphon-breaking is a passive method that can prevent a LOCA. In this study, either a line or a hole is used as a siphon-breaker, and the effect of various parameters, such as the siphon-breaker size, pipe rupture point, pipe rupture size, and the presence of an orifice, are investigated using an experimental facility similar in size to a full-scale reactor. (authors)

  13. Tidally-induced thermonuclear Supernovae

    E-Print Network [OSTI]

    S. Rosswog; E. Ramirez-Ruiz; W. R. Hix

    2008-11-13T23:59:59.000Z

    We discuss the results of 3D simulations of tidal disruptions of white dwarfs by moderate-mass black holes as they may exist in the cores of globular clusters or dwarf galaxies. Our simulations follow self-consistently the hydrodynamic and nuclear evolution from the initial parabolic orbit over the disruption to the build-up of an accretion disk around the black hole. For strong enough encounters (pericentre distances smaller than about 1/3 of the tidal radius) the tidal compression is reversed by a shock and finally results in a thermonuclear explosion. These explosions are not restricted to progenitor masses close to the Chandrasekhar limit, we find exploding examples throughout the whole white dwarf mass range. There is, however, a restriction on the masses of the involved black holes: black holes more massive than $2\\times 10^5$ M$_\\odot$ swallow a typical 0.6 M$_\\odot$ dwarf before their tidal forces can overwhelm the star's self-gravity. Therefore, this mechanism is characteristic for black holes of moderate masses. The material that remains bound to the black hole settles into an accretion disk and produces an X-ray flare close to the Eddington limit of $L_{\\rm Edd} \\simeq 10^{41} {\\rm erg/s} M_{\\rm bh}/1000 M$_\\odot$), typically lasting for a few months. The combination of a peculiar thermonuclear supernova together with an X-ray flare thus whistle-blows the existence of such moderate-mass black holes. The next generation of wide field space-based instruments should be able to detect such events.

  14. Electron screening effect on stellar thermonuclear fusion

    E-Print Network [OSTI]

    Potekhin, A Y

    2013-01-01T23:59:59.000Z

    We study the impact of plasma correlation effects on nonresonant thermonuclear reactions for various stellar objects, namely in the liquid envelopes of neutron stars, and the interiors of white dwarfs, low-mass stars, and substellar objects. We examine in particular the effect of electron screening on the enhancement of thermonuclear reactions in dense plasmas within and beyond the linear mixing rule approximation as well as the corrections due to quantum effects at high density. In addition, we examine some recent unconventional (Yukawa-potential and "quantum-tail") theoretical results on stellar thermonuclear fusions and show that these scenarios do not apply to stellar conditions.

  15. The physics of antimatter induced fusion and thermonuclear explosions

    E-Print Network [OSTI]

    Andre Gsponer; Jean-pierre Hurni

    triggering large scale thermonuclear explosions is investigated. The number of antiproton annihilations

  16. Workshop on Thermonuclear Reaction Rates for Astrophysics Applications

    E-Print Network [OSTI]

    Workshop on Thermonuclear Reaction Rates for Astrophysics Applications 24-25 November 2011, Athens circular for the Workshop on Thermonuclear Reaction Rates for Astrophysics Applications, to be held of thermonuclear reaction rates. The topics of the workshop, in relation with thermonuclear reaction rates

  17. Material unaccounted for at the Southwest Experimental Fast Oxide Reactor: The SEFOR MUF

    SciTech Connect (OSTI)

    Higinbotham, W.A.

    1994-11-07T23:59:59.000Z

    The U.S. Atomic Energy Commission contracted with the General Electric Company to design, construct, and operate the Southwest Experimental Fast Oxide Reactor (SEFOR) to measure the Doppler effect for fast neutron breeder reactors. It contracted with Nuclear Fuel Services to fabricate the fuel rods for the reactor. When the reactor went critical in May, 1969, it appeared that some of the mixed uranium-plutonium oxide (MOX) fuel rods did not contain the specified quantity of plutonium. The SEFOR operators soon found several fuel rods which appeared to be low in plutonium. The safeguards group at Brookhaven was asked to look into the problem and, if possible, determine how much plutonium was missing from the unirradiated rods and from the larger number which had been slightly irradiated in the reactor. It was decided that the plutonium content of the unirradiated and irradiated rods could be measured relative to a reference rod using a high resolution gamma-ray detector and also by neutron measurements using an auto-correlation circuit recently developed at the Naval Research Laboratory (NRL). During the next two years, Brookhaven personnel and C.V. Strain of NRL made several trips to the SEFOR reactor. About 250 of the 775 rods were measured by two or more methods, using a sodium-iodide detector, a high-resolution germanium detector, a neutron detector, or the reactor (to measure reactivity). The research team concluded that 4.6 {+-} 0.46 kg of plutonium was missing out of the 433 kg that the rods should have contained. This report describes the SEFOR experiment and the procedures used to determine the material unaccounted for, or MUF.

  18. Computational and experimental prediction of dust production in pebble bed reactors, Part II

    SciTech Connect (OSTI)

    Mie Hiruta; Gannon Johnson; Maziar Rostamian; Gabriel P. Potirniche; Abderrafi M. Ougouag; Massimo Bertino; Louis Franzel; Akira Tokuhiro

    2013-10-01T23:59:59.000Z

    This paper is the continuation of Part I, which describes the high temperature and high pressure helium environment wear tests of graphite–graphite in frictional contact. In the present work, it has been attempted to simulate a Pebble Bed Reactor core environment as compared to Part I. The experimental apparatus, which is a custom-designed tribometer, is capable of performing wear tests at PBR relevant higher temperatures and pressures under a helium environment. This environment facilitates prediction of wear mass loss of graphite as dust particulates from the pebble bed. The experimental results of high temperature helium environment are used to anticipate the amount of wear mass produced in a pebble bed nuclear reactor.

  19. UV Light Curves of Thermonuclear Supernovae

    E-Print Network [OSTI]

    S. I. Blinnikov; E. I. Sorokina

    2000-03-17T23:59:59.000Z

    Ultraviolet light curves are calculated for several thermonuclear supernova models using a multifrequency radiation hydrodynamic code. It is found that Chandrasekhar-mass models produce very similar light curves both for detonation and deflagration. Sub-Chandrasekhar-mass models essentially differ from ``normal'' Chandrasekhar ones regarding behaviour of their UV fluxes. Differences in absolute brightness and in shape of light curves of thermonuclear supernovae could be detectable up to 300 Mpc with modern UV space telescopes.

  20. An Experimental Test Facility to Support Development of the Fluoride Salt Cooled High Temperature Reactor

    SciTech Connect (OSTI)

    Yoder Jr, Graydon L [ORNL] [ORNL; Aaron, Adam M [ORNL] [ORNL; Cunningham, Richard Burns [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Fugate, David L [ORNL] [ORNL; Holcomb, David Eugene [ORNL] [ORNL; Kisner, Roger A [ORNL] [ORNL; Peretz, Fred J [ORNL] [ORNL; Robb, Kevin R [ORNL] [ORNL; Wilgen, John B [ORNL] [ORNL; Wilson, Dane F [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    The need for high-temperature (greater than 600 C) energy exchange and delivery systems is significantly increasing as the world strives to improve energy efficiency and develop alternatives to petroleum-based fuels. Liquid fluoride salts are one of the few energy transport fluids that have the capability of operating at high temperatures in combination with low system pressures. The Fluoride Salt-Cooled High-Temperature Reactor design uses fluoride salt to remove core heat and interface with a power conversion system. Although a significant amount of experimentation has been performed with these salts, specific aspects of this reactor concept will require experimental confirmation during the development process. The experimental facility described here has been constructed to support the development of the Fluoride Salt Cooled High Temperature Reactor concept. The facility is capable of operating at up to 700 C and incorporates a centrifugal pump to circulate FLiNaK salt through a removable test section. A unique inductive heating technique is used to apply heat to the test section, allowing heat transfer testing to be performed. An air-cooled heat exchanger removes added heat. Supporting loop infrastructure includes a pressure control system; trace heating system; and a complement of instrumentation to measure salt flow, temperatures, and pressures around the loop. The initial experiment is aimed at measuring fluoride salt heat transfer inside a heated pebble bed similar to that used for the core of the pebble bed advanced high-temperature reactor. This document describes the details of the loop design, auxiliary systems used to support the facility, the inductive heating system, and facility capabilities.

  1. White dwarf mergers,White dwarf mergers, thermonuclear supernovae,thermonuclear supernovae,

    E-Print Network [OSTI]

    Hinton, Jim

    White dwarf mergers,White dwarf mergers, thermonuclear supernovae,thermonuclear supernovae fusion is ignited. Degenerate, hence runaway. #12;CO white dwarf accretes, either from companion, or from disk after merger. As it approaches maximum mass, C fusion is ignited. Degenerate, hence runaway. SN Ia

  2. Thermal-Hydraulic Analysis of an Experimental Reactor Cavity Cooling System with Air

    SciTech Connect (OSTI)

    Corradin, Michael; Hassan, Yassin; Tokuhiro, Akira

    2014-10-15T23:59:59.000Z

    This experimental study investigates the thermal hydraulic behavior and the heat removal performance for a scaled Reactor Cavity Cooling System (RCCS) with air. A quarter-scale RCCS facility was designed and built based on a full-scale General Atomics (GA) RCCS design concept for the Modular High Temperature Gas Reactor (MHTGR). The GA RCCS is a passive cooling system that draws in air to use as the cooling fluid to remove heat radiated from the reactor pressure vessel to the air-cooled riser tubes and discharged the heated air into the atmosphere. Scaling laws were used to preserve key aspects and to maintain similarity. The scaled air RCCS facility at UW-Madison is a quarter-scale reduced length experiment housing six riser ducts that represent a 9.5° sector slice of the full-scale GA air RCCS concept. Radiant heaters were used to simulate the heat radiation from the reactor pressure vessel. The maximum power that can be achieved with the radiant heaters is 40 kW with a peak heat flux of 25 kW per meter squared. The quarter-scale RCCS was run under different heat loading cases and operated successfully. Instabilities were observed in some experiments in which one of the two exhaust ducts experienced a flow reversal for a period of time. The data and analysis presented show that the RCCS has promising potential to be a decay heat removal system during an accident scenario.

  3. aries-rs fusion reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and Utilization Websites Summary: FF (1984) Introduction to plasma physics and controlled thermonuclear fusion. Plenum, New York If cheaper fusion reactors were developed, such as...

  4. Frequency response testing at Experimental Breeder Reactor II using discrete-level periodic signals

    SciTech Connect (OSTI)

    Rhodes, W.D.; Larson, H.A. (Idaho State Univ., Pocatello, ID (USA). Coll. of Engineering); Dean, E.M. (Argonne National Lab., Idaho Falls, ID (USA))

    1990-01-01T23:59:59.000Z

    The Experimental Breeder Reactor 2 (EBR-2) reactivity-to-power frequency-response function was measured with pseudo-random, discrete-level, periodic signals. The reactor power deviation was small with insignificant perturbation of normal operation and in-place irradiation experiments. Comparison of results with measured rod oscillator data and with theoretical predictions show good agreement. Moreover, measures of input signal quality (autocorrelation function and energy spectra) confirm the ability to enable this type of frequency response determination at EBR-2. Measurements were made with the pseudo-random binary sequence, quadratic residue binary sequence, pseudo-random ternary sequence, and the multifrequency binary sequence. 10 refs., 7 figs., 3 tabs.

  5. Antimatter induced fusion and thermonuclear explosions

    E-Print Network [OSTI]

    Gsponer, A; Gsponer, Andre; Hurni, Jean-Pierre

    1987-01-01T23:59:59.000Z

    The feasibility of using antihydrogen for igniting inertial confinement fusion pellets or triggering large scale thermonuclear explosions is investigated. The number of antiproton annihilations required to start a thermonuclear burn wave in either DT or Li_2DT is found to be about 10^{21}/k^2, where k is the compression factor of the fuel to be ignited. In the second part, the technologies for producing antiprotons with high energy accelerator systems and the means for manipulating and storing microgram amounts of antihydrogen are examined. While there seems to be no theoretical obstacles to the production of 10^{18} antiprotons per day (the amount required for triggering one thermonuclear bomb), the construction of such a plant involves several techniques which are between 3 and 4 orders of magnitude away from present day technology.

  6. Convective heating analysis of an IFE target in a high temperature, low Reynolds number xenon environment

    E-Print Network [OSTI]

    Holdener, Dain Steffen

    2011-01-01T23:59:59.000Z

    conditions required for thermonuclear burn lies on the edgeThe International Thermonuclear Experimental Reactor (ITER)is successful in achieving thermonuclear burn. While NIF is

  7. Experimental Evaluation of the Thermal Performance of a Water Shield for a Surface Power Reactor

    SciTech Connect (OSTI)

    Pearson, J. Boise; Stewart, Eric T. [NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Reid, Robert S. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States)

    2007-01-30T23:59:59.000Z

    Water based reactor shielding is being investigated for use on initial lunar surface power systems. A water shield may lower overall cost (as compared to development cost for other materials) and simplify operations in the setup and handling. The thermal hydraulic performance of the shield is of significant interest. The mechanism for transferring heat through the shield is natural convection. Natural convection in a 100 kWt lunar surface reactor shield design is evaluated with 2 kW power input to the water in the Water Shield Testbed (WST) at the NASA Marshall Space Flight Center. The experimental data from the WST is used to validate a CFD model. Performance of the water shield on the lunar surface is then predicted with a CFD model anchored to test data. The experiment had a maximum water temperature of 75 deg. C. The CFD model with 1/6-g predicts a maximum water temperature of 88 deg. C with the same heat load and external boundary conditions. This difference in maximum temperature does not greatly affect the structural design of the shield, and demonstrates that it may be possible to use water for a lunar reactor shield.

  8. Modeling and Experimental Studies of Mercury Oxidation and Adsorption in a Fixed-Bed Reactor

    SciTech Connect (OSTI)

    Paula A. Buitrago, Mike Morrill, JoAnn S. Lighty, Geoffrey D.; Silcox,

    2009-06-15T23:59:59.000Z

    This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300- W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150oC. All methane, air, SO2, and halogen species were introduced through the burner to produce a radical pool representative of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150°C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO2, and NO2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and intraparticle diffusion. The Freundlich isotherm more accurately described in-flight mercury capture. Using these parameters, very little intraparticle diffusion was evident. Consistent with other data, smaller particles resulted in higher mercury uptake due to available surface area. Therefore, it is important to capture the particle size distribution in the model. At typical full-scale sorbent feed rates, the calculations underpredicted adsorption, suggesting that wall effects can account for as much as 50 percent of the removal, making it an important factor in entrained-mercury adsorption models.

  9. THE POSSIBILITY OF PRODUCING THERMONUCLEAR REACTIONS IN A GASEOUS DISCHARGE*

    E-Print Network [OSTI]

    THE POSSIBILITY OF PRODUCING THERMONUCLEAR REACTIONS IN A GASEOUS DISCHARGE* I.V. Kurchatov of the energy of thermonuclear reactions. Physicists the world over are attracted by the extraordinarily interest- ing and very difficult task of controlling thermonuclear reactiom. Investigations in this field

  10. Introduction to Magnetic Thermonuclear Fusion and

    E-Print Network [OSTI]

    Shihadeh, Alan

    Introduction to Magnetic Thermonuclear Fusion and Related Research Projects Ghassan Antar Fusion 2. Research on Turbulence (Theory and Experiment) 3. Research on Disruptions 4. Research on Plasma Facing Components #12;Ghassan Y. ANTAR 3 Fusion Occurs when Two Nuclei Unite to Form One The Energy

  11. Resonances and the thermonuclear reaction rate

    E-Print Network [OSTI]

    M. S. Hussein; M. Ueda; A. J. Sargeant; M. P. Pato

    2003-07-21T23:59:59.000Z

    We present an approximate analytic expression for thermonuclear reaction rate of charged particles when the cross section contains a single narrow or wide resonance described by a Breit-Wigner shape. The resulting expression is uniformly valid as the effective energy and resonance energy coalesce. We use our expressions to calculate the reaction rate for $^{12}$C(p,$\\gamma$)$^{13}$N.

  12. Condensed hydrogen for thermonuclear fusion

    SciTech Connect (OSTI)

    Kucheyev, S. O.; Hamza, A. V. [Nanoscale Synthesis and Characterization Laboratory, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2010-11-15T23:59:59.000Z

    Inertial confinement fusion (ICF) power, in either pure fusion or fission-fusion hybrid reactors, is a possible solution for future world's energy demands. Formation of uniform layers of a condensed hydrogen fuel in ICF targets has been a long standing materials physics challenge. Here, we review the progress in this field. After a brief discussion of the major ICF target designs and the basic properties of condensed hydrogens, we review both liquid and solid layering methods, physical mechanisms causing layer nonuniformity, growth of hydrogen single crystals, attempts to prepare amorphous and nanostructured hydrogens, and mechanical deformation behavior. Emphasis is given to current challenges defining future research areas in the field of condensed hydrogens for fusion energy applications.

  13. alkaline tungsten matrix: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Thermonuclear Experimental Reactor Organization, Cadarache, FRANCE 3 Plasma Science and Fusion Thermonuclear Experimental Reactor). Tungsten (W) is the plasma-facing material of...

  14. anthocyanins facilitate tungsten: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Thermonuclear Experimental Reactor Organization, Cadarache, FRANCE 3 Plasma Science and Fusion Thermonuclear Experimental Reactor). Tungsten (W) is the plasma-facing material of...

  15. DEPARTMENT OF ENERGY Since 2001, the Administration

    E-Print Network [OSTI]

    Gen, the Carbon Sequestration Leadership Forum, and the International Thermonuclear Experimental Reactor fusion to the International Thermonuclear Experimental Reactor fusion energy project. Accelerating Breakthroughs

  16. IAEA-CN-SO/F-I-4 ITER: CONCEPT DEFINITION*

    E-Print Network [OSTI]

    way. 1. INTRODUCTION The activity of the International Thermonuclear Experimental Reactor (ITER. * The activity of the International Thermonuclear Experimental Reactor (ITER) is conducted under the auspices

  17. Senate Appropriations Committee Report FY04 Energy and Water Development Act

    E-Print Network [OSTI]

    as a viable energy source. International Thermonuclear Experimental Reactor - The Committee recommendation negotiations aimed at building the International Thermonuclear Experimental Reactor (ITER), a burning plasma

  18. Neutron capture of 26Mg at thermonuclear energies

    E-Print Network [OSTI]

    P. Mohr; H. Beer; H. Oberhummer; G. Staudt

    1998-05-20T23:59:59.000Z

    The neutron capture cross section of 26Mg was measured relative to the known gold cross section at thermonuclear energies using the fast cyclic activation technique. The experiment was performed at the 3.75 MV Van-de-Graaff accelerator, Forschungszentrum Karlsruhe. The experimental capture cross section is the sum of resonant and direct contributions. For the resonance at E(n,lab) = 220 keV our new results are in disagreement with the data from Weigmann et al. An improved Maxwellian averaged capture cross section is derived from the new experimental data taking into account s- and p-wave capture and resonant contributions. The properties of so-called potential resonances which influence the p-wave neutron capture of 26}Mg are discussed in detail.

  19. Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations

    E-Print Network [OSTI]

    Christian Iliadis; Richard Longland; Alain Coc; F. X. Timmes; Art E. Champagne

    2014-09-19T23:59:59.000Z

    Rigorous statistical methods for estimating thermonuclear reaction rates and nucleosynthesis are becoming increasingly established in nuclear astrophysics. The main challenge being faced is that experimental reaction rates are highly complex quantities derived from a multitude of different measured nuclear parameters (e.g., astrophysical S-factors, resonance energies and strengths, particle and gamma-ray partial widths). We discuss the application of the Monte Carlo method to two distinct, but related, questions. First, given a set of measured nuclear parameters, how can one best estimate the resulting thermonuclear reaction rates and associated uncertainties? Second, given a set of appropriate reaction rates, how can one best estimate the abundances from nucleosynthesis (i.e., reaction network) calculations? The techniques described here provide probability density functions that can be used to derive statistically meaningful reaction rates and final abundances for any desired coverage probability. Examples are given for applications to s-process neutron sources, core-collapse supernovae, classical novae, and big bang nucleosynthesis.

  20. Formulation and experimental evaluation of closed-form control laws for the rapid maneuvering of reactor neutronic power

    SciTech Connect (OSTI)

    Bernard, J.A. (Massachusetts Inst. of Tech., Cambridge, MA (USA). Nuclear Reactor Lab.)

    1989-09-01T23:59:59.000Z

    This report describes both the theoretical development and the experimental evaluation of a novel, robust methodology for the time-optimal adjustment of a reactor's neutronic power under conditions of closed-loop digital control. Central to the approach are the MIT-SNL Period-Generated Minimum Time Control Laws' which determine the rate at which reactivity should be changed in order to cause a reactor's neutronic power to conform to a specified trajectory. Using these laws, reactor power can be safely raised by five to seven orders of magnitude in a few seconds. The MIT-SNL laws were developed to facilitate rapid increases of neutronic power on spacecraft reactors operating in an SDI environment. However, these laws are generic and have other applications including the rapid recovery of research and test reactors subsequent to an unanticipated shutdown, power increases following the achievement of criticality on commercial reactors, power adjustments on commercial reactors so as to minimize thermal stress, and automated startups. The work reported here was performed by the Massachusetts Institute of Technology under contract to the Sandia National Laboratories. Support was also provided by the US Department of Energy's Division of University and Industry Programs. The work described in this report is significant in that a novel solution to the problem of time-optimal control of neutronic power was identified, in that a rigorous description of a reactor's dynamics was derived in that the rate of change of reactivity was recognized as the proper control signal, and in that extensive experimental trials were conducted of these newly developed concepts on actual nuclear reactors. 43 refs., 118 figs., 11 tabs.

  1. Merging White Dwarfs and Thermonuclear Supernovae

    E-Print Network [OSTI]

    van Kerkwijk, Marten H

    2012-01-01T23:59:59.000Z

    Thermonuclear supernovae result when interaction with a companion reignites nuclear fusion in a carbon-oxygen white dwarf, causing a thermonuclear runaway, a catastrophic gain in pressure, and the disintegration of the whole white dwarf. It is usually thought that fusion is reignited in near-pycnonuclear conditions when the white dwarf approaches the Chandrasekhar mass. I briefly describe two long-standing problems faced by this scenario, and our suggestion that these supernovae instead result from mergers of carbon-oxygen white dwarfs, including those that produce sub-Chandrasekhar mass remnants. I then turn to possible observational tests, in particular those that test the absence or presence of electron captures during the burning.

  2. Solar Models and NACRE thermonuclear reaction rates

    E-Print Network [OSTI]

    P. Morel; B. Pichon; J. Provost; G. Berthomieu

    1999-07-27T23:59:59.000Z

    Using the most recent updated physics, calibrated solar models have been computed with the new thermonuclear reaction rates of NACRE, the recently available European compilation. Comparisons with models computed with the reaction rates of Caughlan & Fowler (\\cite{cf88}) and of Adelberger et al. (\\cite{a98}) are made for global structure, expected neutrinos fluxes, chemical composition and sound speed profiles, helioseismological properties of p-modes and g-modes.

  3. Thermonuclear processes of the Universe

    E-Print Network [OSTI]

    Sergey B. Dubovichenko

    2011-08-12T23:59:59.000Z

    The book considers some theoretical questions of nuclear astro-physics thermal energies and light atomic nuclei. For the analysis of re-actions is used potential two cluster model of light nuclei with classifica-tion of states by orbital schemes. On its basis photonuclear processes in p2H, p3H, p6Li, p7Li, p9Be and p12C, and also 2H4He, 3H4He, 3He4He and 4He12C channels are considered and astrophysical S - factors corre-sponding to them are calculated. It is shown, that used methods allow to describe well available experimental data in the field of astrophysical energies. This Book is written in Russian, but will perhaps present certain interest.

  4. Argonne's rich scientific heritage Argonne's Experimental Breeder Reactor-I in Idaho lit this string of four

    E-Print Network [OSTI]

    Kemner, Ken

    Argonne's rich scientific heritage Argonne's Experimental Breeder Reactor-I in Idaho lit was December 20, 1951. Argonne National Laboratory is a U.S. Department of Energy laboratory managed by UChicago Argonne, LLC October 2010Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439

  5. Experimental and Analytic Study on the Core Bypass Flow in a Very High Temperature Reactor

    SciTech Connect (OSTI)

    Richard Schultz

    2012-04-01T23:59:59.000Z

    Core bypass flow has been one of key issues in the very high temperature reactor (VHTR) design for securing core thermal margins and achieving target temperatures at the core exit. The bypass flow in a prismatic VHTR core occurs through the control element holes and the radial and axial gaps between the graphite blocks for manufacturing and refueling tolerances. These gaps vary with the core life cycles because of the irradiation swelling/shrinkage characteristic of the graphite blocks such as fuel and reflector blocks, which are main components of a core's structure. Thus, the core bypass flow occurs in a complicated multidimensional way. The accurate prediction of this bypass flow and counter-measures to minimize it are thus of major importance in assuring core thermal margins and securing higher core efficiency. Even with this importance, there has not been much effort in quantifying and accurately modeling the effect of the core bypass flow. The main objectives of this project were to generate experimental data for validating the software to be used to calculate the bypass flow in a prismatic VHTR core, validate thermofluid analysis tools and their model improvements, and identify and assess measures for reducing the bypass flow. To achieve these objectives, tasks were defined to (1) design and construct experiments to generate validation data for software analysis tools, (2) determine the experimental conditions and define the measurement requirements and techniques, (3) generate and analyze the experimental data, (4) validate and improve the thermofluid analysis tools, and (5) identify measures to control the bypass flow and assess its performance in the experiment.

  6. Analysis of Experimental Data for High Burnup PWR Spent Fuel Isotopic Validation - Vandellos II Reactor

    SciTech Connect (OSTI)

    Ilas, Germina [ORNL; Gauld, Ian C [ORNL

    2011-01-01T23:59:59.000Z

    This report is one of the several recent NUREG/CR reports documenting benchmark-quality radiochemical assay data and the use of the data to validate computer code predictions of isotopic composition for spent nuclear fuel, to establish the uncertainty and bias associated with code predictions. The experimental data analyzed in the current report were acquired from a high-burnup fuel program coordinated by Spanish organizations. The measurements included extensive actinide and fission product data of importance to spent fuel safety applications, including burnup credit, decay heat, and radiation source terms. Six unique spent fuel samples from three uranium oxide fuel rods were analyzed. The fuel rods had a 4.5 wt % {sup 235}U initial enrichment and were irradiated in the Vandellos II pressurized water reactor operated in Spain. The burnups of the fuel samples range from 42 to 78 GWd/MTU. The measurements were used to validate the two-dimensional depletion sequence TRITON in the SCALE computer code system.

  7. Probing thermonuclear supernova explosions with neutrinos

    E-Print Network [OSTI]

    A. Odrzywolek; T. Plewa

    2011-03-27T23:59:59.000Z

    Aims: We present neutrino light curves and energy spectra for two representative type Ia supernova explosion models: a pure deflagration and a delayed detonation. Methods: We calculate the neutrino flux from $\\beta$ processes using nuclear statistical equilibrium abundances convoluted with approximate neutrino spectra of the individual nuclei and the thermal neutrino spectrum (pair+plasma). Results: Although the two considered thermonuclear supernova explosion scenarios are expected to produce almost identical electromagnetic output, their neutrino signatures appear vastly different, which allow an unambiguous identification of the explosion mechanism: a pure deflagration produces a single peak in the neutrino light curve, while the addition of the second maximum characterizes a delayed-detonation. We identified the following main contributors to the neutrino signal: (1) weak electron neutrino emission from electron captures (in particular on the protons Co55 and Ni56) and numerous beta-active nuclei produced by the thermonuclear flame and/or detonation front, (2) electron antineutrinos from positron captures on neutrons, and (3) the thermal emission from pair annihilation. We estimate that a pure deflagration supernova explosion at a distance of 1 kpc would trigger about 14 events in the future 50 kt liquid scintillator detector and some 19 events in a 0.5 Mt water Cherenkov-type detector. Conclusions: While in contrast to core-collapse supernovae neutrinos carry only a very small fraction of the energy produced in the thermonuclear supernova explosion, the SN Ia neutrino signal provides information that allows us to unambiguously distinguish between different possible explosion scenarios. These studies will become feasible with the next generation of proposed neutrino observatories.

  8. The Fractional Kinetic Equation and Thermonuclear Functions

    E-Print Network [OSTI]

    H. J. Haubold; A. M. Mathai

    2000-01-16T23:59:59.000Z

    The paper discusses the solution of a simple kinetic equation of the type used for the computation of the change of the chemical composition in stars like the Sun. Starting from the standard form of the kinetic equation it is generalized to a fractional kinetic equation and its solutions in terms of H-functions are obtained. The role of thermonuclear functions, which are also represented in terms of G- and H-functions, in such a fractional kinetic equation is emphasized. Results contained in this paper are related to recent investigations of possible astrophysical solutions of the solar neutrino problem.

  9. NASA's RXTE captures thermonuclear behavior of unique neutron star | EurekAlert! Science ..

    E-Print Network [OSTI]

    ... 2012 NASA's RXTE captures thermonuclear behavior of unique neutron star ... powered by a barrage of thermonuclear explosions on the star's ... minutes and caused by a thermonuclear explosion on the neutron star ...

  10. Experimental Results from an Antineutrino Detector for Cooperative Monitoring of Nuclear Reactors

    SciTech Connect (OSTI)

    Bowden, N S; Bernstein, A; Allen, M; Brennan, J S; Cunningham, M; Estrada, J K; Greaves, C R; Hagmann, C; Lund, J; Mengesha, W; Weinbeck, T D; Winant, C D

    2006-09-18T23:59:59.000Z

    Our collaboration has designed, installed, and operated a compact antineutrino detector at a nuclear power station, for the purpose of monitoring the power and plutonium content of the reactor core. This paper focuses on the basic properties and performance of the detector. We describe the site, the reactor source, and the detector, and provide data that clearly show the expected antineutrino signal. Our data and experience demonstrate that it is possible to operate a simple, relatively small, antineutrino detector near a reactor, in a non-intrusive and unattended mode for months to years at a time, from outside the reactor containment, with no disruption of day-to-day operations at the reactor site. This unique real-time cooperative monitoring capability may be of interest for the International Atomic Energy Agency (IAEA) reactor safeguards program and similar regimes.

  11. Control of tearing modes in toroidal fusion experiments using ``designer'' error fields

    E-Print Network [OSTI]

    Rossi, Enrico

    experimental results strongly suggest that further progress in obtaining thermonuclear reactor grade plasmas, placing feedback coils this close to a thermonuclear plasma is essentially impossible in a reactor

  12. anaerobic reactor star: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    1 Introduction About the Next Three Sets of Class Notes Prestwich, Ken 6 Stars as thermonuclear reactors: their fuels and ashes Nuclear Theory (arXiv) Summary: Atomic nuclei are...

  13. aspects experimental developments: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Amit 10 PUBLISHED VERSION Design, performance, and grounding aspects of the International Thermonuclear Experimental Plasma Physics and Fusion Websites Summary: PUBLISHED VERSION...

  14. Oscillations During Thermonuclear X-ray Bursts

    E-Print Network [OSTI]

    Tod E. Strohmayer

    2001-01-12T23:59:59.000Z

    High amplitude, nearly coherent X-ray brightness oscillations during thermonuclear X-ray bursts were discovered with the Rossi X-ray Timing Explorer (RXTE) in early 1996. Spectral and timing evidence strongly supports the conclusion that these oscillations are caused by rotational modulation of the burst emission and that they reveal the spin frequency of neutron stars in low mass X-ray binaries, a long sought goal of X-ray astronomy. Studies carried out over the past year have led to the discovery of burst oscillations in four new sources, bringing to ten the number with confirmed burst oscillations. I review the status of our knowledge of these oscillations and indicate how they can be used to probe the physics of neutron stars. For a few burst oscillation sources it has been proposed that the strongest and most ubiquitous frequency is actually the first overtone of the spin frequency and hence that two nearly antipodal hot spots are present on the neutron star. This inference has important implications for both the physics of thermonuclear burning as well as the mass - radius relation for neutron stars, so its confirmation is crucial. I discuss recent attempts to confirm this hypothesis for 4U 1636-53, the source for which a signal at the putative fundamental (290 Hz) has been claimed.

  15. The physics of antimatter induced fusion and thermonuclear explosions

    E-Print Network [OSTI]

    Andre Gsponer; Jean-pierre Hurni

    The feasibility of using antihydrogen for igniting inertial confinement fusion pellets or triggering large scale thermonuclear explosions is investigated. The number of antiproton annihilations required to start a thermonuclear burn wave in either DT or Li2DT is found to be about 10 21 /k 2, where

  16. Wideband Heterodyne QWIP Receiver Development for Thermonuclear Fusion Measurements

    SciTech Connect (OSTI)

    Bennett, C.A.; Buchanan, M.; Hutchinson, D.P.; Liu, H.C.; Richards, R.K.; Simpson, M.L.

    1998-11-01T23:59:59.000Z

    Oak Ridge National Laboratory (ORNL) has been developing heterodyne receivers for plasma diagnostic applications for over 20 years. One area of this work has been the development of a diagnostic system for the measurement of the energy of alpha particles created in a thermonuclear fusion reactor. These particles originate with an energy of 3.5 MeV and cool to the thermal energy of the plasma (around 15 keV) after several seconds. To measure the velocity distribution of these alpha particles, a Thomson scattering diagnostic is under development based on a high power CO{sub 2} laser at 10 microns with a heterodyne receiver. The Doppler shift generated by Thomson scattering of the alpha particles requires a wideband heterodyne receiver (greater than 10 GHz). Because Mercury-Cadimum-Telluride (MCT) detectors are limited to a bandwidth of approximately 2 GHz, a Quantum Well Infrared Photodetector (QWIP) detector was obtained from the National Research Council of Canada (NRC) and evaluated for its heterodyne performance using the heterodyne testing facility developed at ORNL.

  17. Short Term Irradiation Test of Fuel Containing Minor Actinides Using the Experimental Fast Reactor Joyo

    SciTech Connect (OSTI)

    Sekine, Takashi; Soga, Tomonori; Koyama, Shin-ichi; Aoyama, Takafumi [Oarai Research and Development Center, Japan Atomic Energy Agency. 4002 Narita, Oarai, Ibaraki 311-1393 (Japan); Wootan, David [Pacific Northwest National Laboratoy, M/S K8-34, P.O. Box 999 Richland, WA 99352 (United States)

    2007-07-01T23:59:59.000Z

    A mixed oxide containing minor actinides (MA-MOX) fuel irradiation program is being conducted using the experimental fast rector Joyo of the Japan Atomic Energy Agency to research early thermal behavior of MA-MOX fuel. Two irradiation experiments were conducted as part of the short-term phase of this program in May and August 2006. Six prepared fuel pins included MOX fuel containing 3% or 5% americium (Am-MOX), and MOX fuel containing 2% americium and 2% neptunium (Np/Am-MOX). The first test was conducted with high linear heat rates of approximately 430 W/cm maintained during only 10 minutes. After 10 minutes irradiation test, the test subassembly was transferred to the hot cell facility and an Am-MOX pin and a Np/Am-MOX pin were replaced with dummy pins with neutron dosimeters. The test subassembly loaded with the remaining four fuel pins was re-irradiated in Joyo for 24-hours in August 2006 at nearly the same linear power to obtain re-distribution data on MA-MOX fuel. The linear heat rate for each MA-MOX test fuel pin was calculated using the Monte Carlo calculation code MCNP. The calculated fission rates were compared with the measured data based on the Nd-148 method. The maximum linear heat rate was approximately 444{+-}19 W/cm at the actual reactor power of 119.6 MWt. Post irradiation examination of these pins to confirm the absence of fuel melting and the local concentration under irradiation of NpO{sub 2-x} or AmO{sub 2-x}, in the (U,Pu)0{sub 2-x}, fuel are underway. The test results are expected to reduce uncertainties on the margin in the thermal design for MA-MOX fuel. (authors)

  18. Experimental and Thermalhydraulic Code Assessment of the Transient Behavior of the Passive Condenser System in an Advanced Boiling Water Reactor

    SciTech Connect (OSTI)

    S.T. Revankar; W. Zhou; Gavin Henderson

    2008-07-08T23:59:59.000Z

    The main goal of the project was to study analytically and experimentally the condensation heat transfer for the passive condenser system such as GE Economic Simplified Boiling Water Reactor (ESBWR). The effect of noncondensable gas in condenser tube and the reduction of secondary pool water level to the condensation heat transfer coefficient was the main focus in this research. The objectives of this research were to : 1) obtain experimental data on the local and tube averaged condensation heat transfer rates for the PCCS with non-condensable and with change in the secondary pool water, 2) assess the RELAP5 and TRACE computer code against the experimental data, and 3) develop mathematical model and ehat transfer correlation for the condensation phenomena for system code application. The project involves experimentation, theoretical model development and verification, and thermal- hydraulic codes assessment.

  19. INERTIAL FUSION DRIVEN BY INTENSE HEAVY-ION BEAMS

    E-Print Network [OSTI]

    Sharp, W. M.

    2011-01-01T23:59:59.000Z

    Thermonuclear Experimental Reactor), now being constructed in Caderache, France [5]. In contrast, inertial fusion

  20. 70 IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 18, NO. 2, JUNE 2008 High Field Superconducting Solenoids Via High

    E-Print Network [OSTI]

    an essential role in fusion devices, including the Interna- tional Thermonuclear Experimental Reactor [6], [7

  1. Ris-R-1276(EN) Final Report

    E-Print Network [OSTI]

    Thermonuclear Experimental Reactor) [1,2]. Since very little was known about the effect of irradiation

  2. The development and operational testing of an experimental reactor for gas-liquid-solid reaction systems at high temperatures and pressures

    E-Print Network [OSTI]

    Hess, Richard Kenneth

    1985-01-01T23:59:59.000Z

    THE DEVELOPMENT AND OPERATIONAL TESTING OF AN EXPERIMENTAL REACTOR FOR GAS-LIQUID-SOLID REACTION SYSTEMS AT HIGH TEMPERATURES AND PRESSURES A Thesis by RICHARD KENNETH HESS Submitted to the Graduate College of Texas A&M University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1985 Major Subject: Chemical Engineering THE DEVELOPMENT AND OPERATIONAL TESTING OF AN EXPERIMENTAL REACTOR FOR GAS-LIQUID-SOLID REACTION SYSTEMS AT HIGH TEMPERATURES...

  3. The physics of antimatter induced fusion and thermonuclear explosions

    E-Print Network [OSTI]

    Gsponer, A; Gsponer, Andre; Hurni, Jean-Pierre

    1987-01-01T23:59:59.000Z

    The possibility of using antihydrogen for igniting inertial confinement fusion pellets or triggering large scale thermonuclear explosions is investigated. The number of antiproton annihilations required to start a thermonuclear burn wave in either D or Li_2DT is found to be about 10^{21}/k^2, where k is the compression factor of the fuel to be ignited. We conclude that the financial and energy investments needed to produce such amounts of antiprotons would confine applications of antimatter triggered thermonuclear devices to the military domain.

  4. Numerical simulations of welds of thick steel pieces of interest for the thermonuclear fusion ITER machine

    E-Print Network [OSTI]

    Carmignani, B

    2005-01-01T23:59:59.000Z

    Numerical simulations of welds of thick steel pieces of interest for the thermonuclear fusion ITER machine

  5. explosion: Role of hydrogen thermonuclear explosion in support of cometary hypothesis

    E-Print Network [OSTI]

    Y. E. Kim

    2008-01-01T23:59:59.000Z

    deuteron fusion rates and that a thermonuclear explosion may compete with a thermo-chemical explosion

  6. EXTENSION OF THERMONUCLEAR FUNCTIONS THROUGH THE PATHWAY MODEL INCLUDING MAXWELL-BOLTZMANN AND

    E-Print Network [OSTI]

    H. J. Haubold

    of respective thermonuclear functions is being conducted with the help of statistical techniques. The

  7. Measurement of the Fractional Thermonuclear Neutron Yield during Deuterium Neutral-Beam Injection into Deuterium Plasmas

    E-Print Network [OSTI]

    Measurement of the Fractional Thermonuclear Neutron Yield during Deuterium Neutral-Beam Injection into Deuterium Plasmas

  8. Japan considers conceding ITER site to France TOKYO, May 4, Kyodo -(EDS: UPDATING WITH MACHIMURA MEETING WITH BARNIER IN

    E-Print Network [OSTI]

    the planned International Thermonuclear Experimental Reactor in Rokkasho, Aomori Prefecture, and bowing out plant is an experimental facility of thermonuclear fusion, at which nuclear fusion reactions that occur

  9. Thermonuclear 42Ti(p,gamma)43V rate in type I X-ray bursts

    E-Print Network [OSTI]

    He, J J; Brown, B A; Rauscher, T; Hou, S Q; Zhang, Y H; Zhou, X H; Xu, H S

    2014-01-01T23:59:59.000Z

    The thermonuclear rate of the $^{42}$Ti($p$,$\\gamma$)$^{43}$V reaction has been reevaluated based on a recent precise proton separation energy measurement of $S_p$($^{43}$V)=83$\\pm$43 keV. The astrophysical impact of our new rates has been investigated through one-zone postprocessing type I x-ray burst calculations. It shows that the new experimental value of $S_p$ significantly affects the yields of species between A$\\approx$40--45. As well, the precision of the recent experimental $S_p$ value constrains these yields to better than a factor of three.

  10. Thermonuclear Reaction Rate of 23Mg(p,gamma)24$Al

    E-Print Network [OSTI]

    H. Herndl; M. Fantini; C. Iliades; P. M. Endt; H. Oberhummer

    1998-06-05T23:59:59.000Z

    Updated stellar rates for the reaction 23Mg(p,gamma)24Al are calculated by using all available experimental information on 24Al excitation energies. Proton and gamma-ray partial widths for astrophysically important resonances are derived from shell model calculations. Correspondences of experimentally observed 24Al levels with shell model states are based on application of the isobaric multiplet mass equation. Our new rates suggest that the 23Mg(p,gamma)24Al reaction influences the nucleosynthesis in the mass A>20 region during thermonuclear runaways on massive white dwarfs.

  11. Thermonuclear 42Ti(p,gamma)43V rate in type I X-ray bursts

    E-Print Network [OSTI]

    J. J. He; A. Parikh; B. A. Brown; T. Rauscher; S. Q. Hou; Y. H. Zhang; X. H. Zhou; H. S. Xu

    2014-03-10T23:59:59.000Z

    The thermonuclear rate of the $^{42}$Ti($p$,$\\gamma$)$^{43}$V reaction has been reevaluated based on a recent precise proton separation energy measurement of $S_p$($^{43}$V)=83$\\pm$43 keV. The astrophysical impact of our new rates has been investigated through one-zone postprocessing type I x-ray burst calculations. It shows that the new experimental value of $S_p$ significantly affects the yields of species between A$\\approx$40--45. As well, the precision of the recent experimental $S_p$ value constrains these yields to better than a factor of three.

  12. Experimental reactor system for investigation of indirect liquefaction catalysts in slurry phase operation

    SciTech Connect (OSTI)

    Zarochak, M.F.; Pennline, H.W.; Schehl, R.R.

    1984-02-01T23:59:59.000Z

    A detailed description of the slurry (three-phase) reactor scheme employed at the Pittsburgh Energy Technology Center for Fischer-Tropsch synthesis is reported. Emphasis is placed on materials of construction, equipment operation, and product collection and analysis. The unit's functional limits and safety features are also provided. Operational problems and the resolving remedial action are discussed. The reactor scheme now operates such that near isothermal conditions exist over the reactor internal length. Thus, with excellent temperature control assured, reliable information for evaluation of potential catalyst candidates for slurry phase Fischer-Tropsch synthesis is possible within a wide range of operating conditions. Test results with a fused-iron catalyst suspended in a paraffinic liquid medium are given as an example.

  13. Modeling Combustion in Current Candidate Scenarios for Thermonuclear...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Combustion in Current Candidate Scenarios for Thermonuclear Supernovae Mar 26 2015 03:00 PM - 04:00 PM Dean M. Townsley, The University of Alabama, Tuscaloosa Physics Division...

  14. Thermonuclear Burning on Rapidly Accreting Neutron Stars

    E-Print Network [OSTI]

    Lars Bildsten

    1997-09-10T23:59:59.000Z

    Neutron stars in mass-transferring binaries are accreting the hydrogen and helium rich matter from the surfaces of their companions. This article simply explains the physics associated with how that material eventually fuses to form heavier nuclei and the observations of the time dependent phenomena (such as Type I X-ray bursts) associated with the thermally unstable thermonuclear reactions. We explain how the outcome depends on the composition of the accreting matter, the accretion rate and the mass, radius and thermal state of the neutron star. We also introduce many new analytic relations that are convenient for comparisons to both observations and computational results. After explaining nuclear burning for spherically symmetric accretion onto neutron stars, we discuss the possibility of asymmetric burning. In particular, we discuss some of the mysteries from EXOSAT observations of Type I X-Ray bursts and how the solution to these puzzles may lie in considering the lateral propagation of nuclear burning fronts around the star. Fully understanding this problem requires knowledge of parameters previously neglected such as the distribution of fresh fuel on the star, the magnetic field strength, and the stellar rotation. Recent RXTE observations of bursters may finally tell us some of these parameters.

  15. Thermonuclear supernova simulations with stochastic ignition

    E-Print Network [OSTI]

    W. Schmidt; J. C. Niemeyer

    2005-10-14T23:59:59.000Z

    We apply an ad hoc model for dynamical ignition in three-dimensional numerical simulations of thermonuclear supernovae assuming pure deflagrations. The model makes use of the statistical description of temperature fluctuations in the pre-supernova core proposed by Wunsch & Woosley (2004). Randomness in time is implemented by means of a Poisson process. We are able to vary the explosion energy and nucleosynthesis depending on the free parameter of the model which controls the rapidity of the ignition process. However, beyond a certain threshold, the strength of the explosion saturates and the outcome appears to be robust with respect to number of ignitions. In the most energetic explosions, we find about 0.75 solar masses of iron group elements. Other than in simulations with simultaneous multi-spot ignition, the amount of unburned carbon and oxygen at radial velocities of a few 1000 km/s tends to be reduced for an ever increasing number of ignition events and, accordingly, more pronounced layering results.

  16. Experimental Study of the Thermal-Hydraulic Phenomena in the Reactor Cavity Cooling System and Analysis of the Effects of Graphite Dispersion 

    E-Print Network [OSTI]

    Vaghetto, Rodolfo

    2012-07-16T23:59:59.000Z

    An experimental activity was performed to observe and study the effects of graphite dispersion and deposition on thermal hydraulic phenomena in a Reactor Cavity Cooling System (RCCS). The small scale RCCS experimental facility (16.5cm x 16.5cm x 30...

  17. Modeling and Experimental Studies of Mercury Oxidation and Adsorption in a Fixed-Bed and Entrained-Flow Reactor

    SciTech Connect (OSTI)

    Buitrago, Paula A; Morrill, Mike; Lighty, JoAnn S; Silcox, Geoffrey D

    2014-08-20T23:59:59.000Z

    This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300-W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150oC. All methane, air, SO2, and halogen species were introduced through the burner to produce a radical pool representative of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150?C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO2, and NO2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and intraparticle diffusion. The Freundlich isotherm more accurately described in-flight mercury capture. Using these parameters, very little intraparticle diffusion was evident. Consistent with other data, smaller particles resulted in higher mercury uptake due to available surface area. Therefore, it is important to capture the particle size distribution in the model. At typical full-scale sorbent feed rates, the calculations underpredicted adsorption, suggesting that wall effects can account for as much as 50 percent of the removal, making it an important factor in entrained-mercury adsorption models.

  18. Development and experimental validation of a calculation scheme for nuclear heating evaluation in the core of the OSIRIS material testing reactor

    SciTech Connect (OSTI)

    Malouch, F. [Saclay Center CEA, DEN/DANS/DM2S/SERMA, F-91191 Gif-sur-Yvette Cedex (France)

    2011-07-01T23:59:59.000Z

    The control of the temperature in material samples irradiated in a material testing reactor requires the knowledge of the nuclear heating caused by the energy deposition by neutrons and photons interacting in the irradiation device structures. Thus, a neutron-photonic three-dimensional calculation scheme has been developed to evaluate the nuclear heating in experimental devices irradiated in the core of the OSIRIS MTR reactor (CEA/Saclay Center). The aim is to obtain a predictive tool for the nuclear heating estimation in irradiation devices. This calculation scheme is mainly based on the TRIPOLI-4 three-dimensional continuous-energy Monte Carlo transport code, developed by CEA (Saclay Center). An experimental validation has been carried out on the basis of nuclear heating measurements performed in the OSIRIS core. After an overview of the experimental devices irradiated in the OSIRIS reactor, we present the calculation scheme and the first results of the experimental validation. (authors)

  19. Automated operator procedure prompting for startup of Experimental Breeder Reactor-2

    SciTech Connect (OSTI)

    Renshaw, A.W.; Ball, S.J.; Ford, C.E.

    1990-11-01T23:59:59.000Z

    This report describes the development of an operator procedure prompting aid for startup of a nuclear reactor. This operator aid is a preliminary design for a similar aid that eventually will be used with the Advanced Liquid Metal Reactor (ALMR) presently in the design stage. Two approaches were used to develop this operator procedure prompting aid. One method uses an expert system software shell, and the other method uses database software. The preliminary requirements strongly pointed toward features traditionally associated with both database and expert systems software. Database software usually provides data manipulation flexibility and user interface tools, and expert systems tools offer sophisticated data representation and reasoning capabilities. Both methods, including software and associated hardware, are described in this report. Proposals for future enhancements to improve the expert system approach to procedure prompting and for developing other operator aids are also offered. 25 refs., 14 figs.

  20. Experimental Study of the Effect of Graphite Dispersion on the Heat Transfer Phenomena in a Reactor Cavity Cooling System

    SciTech Connect (OSTI)

    Rodolfo Vaghetto; Luigi Capone; Yassin A. Hassan

    2011-05-31T23:59:59.000Z

    An experimental activity was performed to observe and study the effects of graphite dispersion and deposition on thermal-hydraulic phenomena in a reactor cavity cooling system (RCCS). The small-scale RCCS experimental facility (16.5 x 16.5 x 30.4 cm) used for this activity represents half of the reactor cavity with an electrically heated vessel. Water flowing through five vertical pipes removes the heat produced in the vessel and releases it into the environment by mixing with cold water in a large tank. The particle image velocimetry technique was used to study the velocity field of the air inside the cavity. A set of 52 thermocouples was installed in the facility to monitor the temperature profiles of the vessel, pipe walls, and air. Ten grams of a fine graphite powder (average particle size 2 m) was injected into the cavity through a spraying nozzle placed at the bottom of the vessel. The temperatures and air velocity field were recorded and compared with the measurements obtained before the graphite dispersion, showing a decrease of the temperature surfaces that was related to an increase in their emissivity. The results contribute to the understanding of RCCS capability in an accident scenario.

  1. Experimental investigation into fast pyrolysis of biomass using an entrained-flow reactor

    SciTech Connect (OSTI)

    Bohn, M.; Benham, C.

    1981-02-01T23:59:59.000Z

    Pyrolysis experiments were performed using 30 and 90cm entrained-flow reactors, with steam as a carrier gas and two different feedstocks - wheat straw and powdered material drived from municipal solid waste (ECO-II TM). Reactor wall temperature was varied from 700/sup 0/ to 1400/sup 0/C. Gas composition data from the ECO-II tests were comparable to previously reported data but ethylene yield appeared to vary with reactor wall temperature and residence time. The important conclusion from the wheat straw tests is that olefin yields are about one half that obtained from ECO-II. Evidence was found that high olefin yields from ECO-II are due to the presence of plastics in the feedstock. Batch experiments were run on wheat straw using a Pyroprobe/sup TM/. The samples were heated at a high rate (20,000/sup 0/ C/sec) to 1000/sup 0/ and held at 1000/sup 0/C for a variable period of time from 0.05 to 4.95s. For times up to 0.15s volume fractions of ethylene, propylene, and methane increase while that of carbon dioxide decreases. Subsequently, only carbon monoxide and hydrogen are produced. The change may be related to poor thermal contact and suggests caution in using the Pyroprobe.

  2. Thermonuclear reaction rate of $^{18}$Ne($?$,$p$)$^{21}$Na from Monte-Carlo calculations

    E-Print Network [OSTI]

    P. Mohr; R. Longland; C. Iliadis

    2014-12-14T23:59:59.000Z

    The $^{18}$Ne($\\alpha$,$p$)$^{21}$Na reaction impacts the break-out from the hot CNO-cycles to the $rp$-process in type I X-ray bursts. We present a revised thermonuclear reaction rate, which is based on the latest experimental data. The new rate is derived from Monte-Carlo calculations, taking into account the uncertainties of all nuclear physics input quantities. In addition, we present the reaction rate uncertainty and probability density versus temperature. Our results are also consistent with estimates obtained using different indirect approaches.

  3. Thermonuclear reaction rate of $^{18}$Ne($\\alpha$,$p$)$^{21}$Na from Monte-Carlo calculations

    E-Print Network [OSTI]

    Mohr, P; Iliadis, C

    2014-01-01T23:59:59.000Z

    The $^{18}$Ne($\\alpha$,$p$)$^{21}$Na reaction impacts the break-out from the hot CNO-cycles to the $rp$-process in type I X-ray bursts. We present a revised thermonuclear reaction rate, which is based on the latest experimental data. The new rate is derived from Monte-Carlo calculations, taking into account the uncertainties of all nuclear physics input quantities. In addition, we present the reaction rate uncertainty and probability density versus temperature. Our results are also consistent with estimates obtained using different indirect approaches.

  4. Experimental Development and Demonstration of Ultrasonic Measurement Diagnostics for Sodium Fast Reactor Thermal-hydraulics

    SciTech Connect (OSTI)

    Tokuhiro, Akira; Jones, Byron

    2013-09-13T23:59:59.000Z

    This research project will address some of the principal technology issues related to sodium-cooled fast reactors (SFR), primarily the development and demonstration of ultrasonic measurement diagnostics linked to effective thermal convective sensing under normatl and off-normal conditions. Sodium is well-suited as a heat transfer medium for the SFR. However, because it is chemically reactive and optically opaque, it presents engineering accessibility constraints relative to operations and maintenance (O&M) and in-service inspection (ISI) technologies that are currently used for light water reactors. Thus, there are limited sensing options for conducting thermohydraulic measurements under normal conditions and off-normal events (maintenance, unanticipated events). Acoustic methods, primarily ultrasonics, are a key measurement technology with applications in non-destructive testing, component imaging, thermometry, and velocimetry. THis project would have yielded a better quantitative and qualitative understanding of the thermohydraulic condition of solium under varied flow conditions. THe scope of work will evaluate and demonstrate ultrasonic technologies and define instrumentation options for the SFR.

  5. Experimental characterization of an Ion Transport Membrane (ITM) reactor for methane oxyfuel combustion

    E-Print Network [OSTI]

    Apo, Daniel Jolomi

    2012-01-01T23:59:59.000Z

    Ion Transport Membranes (ITM) which conduct both electrons and oxygen ions have been investigated experimentally for oxygen separation and fuel (mostly methane) conversion purposes over the last three decades. The fuel ...

  6. army weapon systems: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Thermonuclear Experimental Reactor and the Nuclear Weapons Proliferation Implications of Thermonuclear-Fusion Energy Systems CiteSeer Summary: This paper contains two parts: (I) A...

  7. arabidopsis converts benzaldehyde: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CERN Preprints Summary: The International Thermonuclear Experimental Reactor (ITER) is a thermonuclear fusion experiment designed to provide long deuterium tritium burning...

  8. ac-line matrix-reactance converter: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CERN Preprints Summary: The International Thermonuclear Experimental Reactor (ITER) is a thermonuclear fusion experiment designed to provide long deuterium tritium burning...

  9. alpha converting enzyme: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CERN Preprints Summary: The International Thermonuclear Experimental Reactor (ITER) is a thermonuclear fusion experiment designed to provide long deuterium tritium burning...

  10. MASSACHUSETTS INSTITUTE OF TECHNOLOGY PLASMA FUSI0.N CENTER

    E-Print Network [OSTI]

    . The International Thermonuclear Experimental Reactor (ITER), a superconducting device, is being designed to achieve transport processes and alpha heating effectiveness,[2] at the re- quired thermonuclear conditions

  11. Ris-R-1007(EN) Influence of Composition, Heat

    E-Print Network [OSTI]

    Thermonuclear Experimental Reactor). The alloys have undergone different pre-irradiation heat treatments which- eration for their applications in the structural components of ITER (Inter- national Thermonuclear

  12. Magnetic Braids Anthony Yeates

    E-Print Network [OSTI]

    Dundee, University of

    flux function Main result Conclusion 2. Thermonuclear confinement devices. ITER (Internat'l Thermonuclear Experimental Reactor). Inside the KSTAR tokamak. Correspond to periodic magnetic braids. 4 / 22

  13. Thermonuclear Fusion with the Sheared Flow Stabilized Z-Pinch

    E-Print Network [OSTI]

    Winterberg, F

    2008-01-01T23:59:59.000Z

    Two basic approaches to producing thermonuclear fusion with a sheared flow stabilized z-pinch are considered. One consists of heating the entire length of the z-pinch column to the required temperatures. The other basic approach considered here involves the concept of fast ignition. A localized "hot-spot" is produced under the proper conditions to ignite a thermonuclear burn wave in the z-pinch plasma. Here we demonstrate that sheared flow stabilization is more efficient in the fast-ignition method with isentropic compression then in a z-pinch where the entire plasma column is heated.

  14. Thermonuclear Supernovae: Simulations of the Deflagration Stage and Their Implications

    E-Print Network [OSTI]

    V. N. Gamezo; A. M. Khokhlov; E. S. Oran; A. Y. Chtchelkanova; R. O. Rosenberg

    2002-12-03T23:59:59.000Z

    Large-scale three-dimensional numerical simulations of the deflagration stage of a thermonuclear supernova explosion show the formation and evolution of a highly convoluted turbulent flame in a gravitational field of an expanding carbon-oxygen white dwarf. The flame dynamics is dominated by the gravity-induced Rayleigh-Taylor instability that controls the burning rate. The thermonuclear deflagration releases enough energy to produce a healthy explosion. The turbulent flame, however, leaves large amounts of unburnt and partially burnt material near the star center, whereas observations imply these materials only in outer layers. This disagreement could be resolved if the deflagration triggers a detonation.

  15. Thermonuclear explosions of Chandrasekhar-mass C+O white dwarfs

    E-Print Network [OSTI]

    M. Reinecke; W. Hillebrandt

    1998-01-01T23:59:59.000Z

    thermonuclear burning, by means of a new two-dimensional numerical code. Since in the interior of such a massive

  16. First direct evidence that filament fracture accompanies degradation of superconducting cables designed for the

    E-Print Network [OSTI]

    Weston, Ken

    designed for the International Thermonuclear Experimental Reactor (ITER) ­ The tokomak fusion reactor ITER generation from nuclear fusion. Eighteen toroidal field coils, each weighing 363 tons, will confine High Magnetic Field Laboratory; 2. International Thermonuclear Experimental Reactor (ITER) Organization

  17. Thermonuclear Supernovae: Simulations of the Deflagration Stage and Their Implications

    E-Print Network [OSTI]

    V. N. Gamezo; A. M. Khokhlov; E. S. Oran; A. Y. Chtchelkanova; R. O. Rosenberg

    2003-01-01T23:59:59.000Z

    Large-scale three-dimensional numerical simulations of the deflagration stage of a thermonuclear supernova explosion show the formation and evolution of a highly convoluted turbulent flame in a gravitational field of an expanding carbon-oxygen white dwarf. The flame dynamics is dominated by the

  18. The LOFT perspective on neutron star thermonuclear bursts

    E-Print Network [OSTI]

    Zand, J J M in 't; Ballantyne, D R; Bhattacharyya, S; Brown, E F; Cavecchi, Y; Chakrabarty, D; Chenevez, J; Cumming, A; Degenaar, N; Falanga, M; Galloway, D K; Heger, A; José, J; Keek, L; Linares, M; Mahmoodifar, S; Malone, C M; Méndez, M; Miller, M C; Paerels, F B S; Poutanen, J; Rózanska, A; Schatz, H; Serino, M; Strohmayer, T E; Suleimanov, V F; Thielemann, F -K; Watts, A L; Weinberg, N N; Woosley, S E; Yu, W; Zhang, S; Zingale, M

    2015-01-01T23:59:59.000Z

    This is a White Paper in support of the mission concept of the Large Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We discuss the potential of LOFT for the study of thermonuclear X-ray bursts on accreting neutron stars. For a summary, we refer to the paper.

  19. Millisecond oscillations during thermonuclear X-ray bursts

    E-Print Network [OSTI]

    Muno, Michael Patrick, 1975-

    2002-01-01T23:59:59.000Z

    I analyze 68 oscillation trains detected in a search of 159 thermonuclear bursts from eight neutron star X-ray binaries observed with the Rossi X-ray Timing Explorer. I use all data that were public as of September 2001. ...

  20. Radiation Damage in Nuclear Fuel for Advanced Burner Reactors: Modeling and Experimental Validation

    SciTech Connect (OSTI)

    Jensen, Niels Gronbech; Asta, Mark; Ozolins, Nigel Browning'Vidvuds; de Walle, Axel van; Wolverton, Christopher

    2011-12-29T23:59:59.000Z

    The consortium has completed its existence and we are here highlighting work and accomplishments. As outlined in the proposal, the objective of the work was to advance the theoretical understanding of advanced nuclear fuel materials (oxides) toward a comprehensive modeling strategy that incorporates the different relevant scales involved in radiation damage in oxide fuels. Approaching this we set out to investigate and develop a set of directions: 1) Fission fragment and ion trajectory studies through advanced molecular dynamics methods that allow for statistical multi-scale simulations. This work also includes an investigation of appropriate interatomic force fields useful for the energetic multi-scale phenomena of high energy collisions; 2) Studies of defect and gas bubble formation through electronic structure and Monte Carlo simulations; and 3) an experimental component for the characterization of materials such that comparisons can be obtained between theory and experiment.

  1. France gets nuclear fusion plant France will get to host the project to build a 10bn-euro (6.6bn) nuclear fusion reactor, in

    E-Print Network [OSTI]

    ) nuclear fusion reactor, in the face of strong competition from Japan. The International Thermonuclear division, which is responsible for the UK's thermonuclear fusion programme, said the decisionFrance gets nuclear fusion plant France will get to host the project to build a 10bn-euro (£6.6bn

  2. The Effects of Thermonuclear Reaction Rate Variations on Nova Nucleosynthesis: A Sensitivity Study

    E-Print Network [OSTI]

    Christian Iliadis; Art Champagne; Jordi Jose; Sumner Starrfield; Paul Tupper

    2002-06-03T23:59:59.000Z

    We investigate the effects of thermonuclear reaction rate uncertainties on nova nucleosynthesis. One-zone nucleosynthesis calculations have been performed by adopting temperature-density-time profiles of the hottest hydrogen-burning zone (i.e., the region in which most of the nucleosynthesis takes place). We obtain our profiles from 7 different, recently published, hydrodynamic nova simulations covering peak temperatures in the range from Tpeak=0.145-0.418 GK. For each of these profiles, we individually varied the rates of 175 reactions within their associated errors and analyzed the resulting abundance changes of 142 isotopes in the mass range below A=40. In total, we performed 7350 nuclear reaction network calculations. We use the most recent thermonuclear reaction rate evaluations for the mass ranges A=1-20 and A=20-40. For the theoretical astrophysicist, our results indicate the extent to which nova nucleosynthesis calculations depend on presently uncertain nuclear physics input, while for the experimental nuclear physicist our results represent at least a qualitative guide for future measurements at stable and radioactive ion beam facilities. We find that present reaction rate estimates are reliable for predictions of Li, Be, C and N abundances in nova nucleosynthesis. However, rate uncertainties of several reactions have to be reduced significantly in order to predict more reliable O, F, Ne, Na, Mg, Al, Si, S, Cl and Ar abundances. Results are presented in tabular form for each adopted nova simulation.

  3. Comparison and validation of HEU and LEU modeling results to HEU experimental benchmark data for the Massachusetts Institute of Technology MITR reactor.

    SciTech Connect (OSTI)

    Newton, T. H.; Wilson, E. H; Bergeron, A.; Horelik, N.; Stevens, J. (Nuclear Engineering Division); (MIT Nuclear Reactor Lab.)

    2011-03-02T23:59:59.000Z

    The Massachusetts Institute of Technology Reactor (MITR-II) is a research reactor in Cambridge, Massachusetts designed primarily for experiments using neutron beam and in-core irradiation facilities. It delivers a neutron flux comparable to current LWR power reactors in a compact 6 MW core using Highly Enriched Uranium (HEU) fuel. In the framework of its non-proliferation policies, the international community presently aims to minimize the amount of nuclear material available that could be used for nuclear weapons. In this geopolitical context, most research and test reactors both domestic and international have started a program of conversion to the use of Low Enriched Uranium (LEU) fuel. A new type of LEU fuel based on an alloy of uranium and molybdenum (UMo) is expected to allow the conversion of U.S. domestic high performance reactors like the MITR-II reactor. Towards this goal, comparisons of MCNP5 Monte Carlo neutronic modeling results for HEU and LEU cores have been performed. Validation of the model has been based upon comparison to HEU experimental benchmark data for the MITR-II. The objective of this work was to demonstrate a model which could represent the experimental HEU data, and therefore could provide a basis to demonstrate LEU core performance. This report presents an overview of MITR-II model geometry and material definitions which have been verified, and updated as required during the course of validation to represent the specifications of the MITR-II reactor. Results of calculations are presented for comparisons to historical HEU start-up data from 1975-1976, and to other experimental benchmark data available for the MITR-II Reactor through 2009. This report also presents results of steady state neutronic analysis of an all-fresh LEU fueled core. Where possible, HEU and LEU calculations were performed for conditions equivalent to HEU experiments, which serves as a starting point for safety analyses for conversion of MITR-II from the use of HEU fuel to the use of UMo LEU fuel.

  4. Strong plasma screening in thermonuclear reactions: Electron drop model

    E-Print Network [OSTI]

    Kravchuk, P A

    2014-01-01T23:59:59.000Z

    We analyze enhancement of thermonuclear fusion reactions due to strong plasma screening in dense matter using a simple electron drop model. The model assumes fusion in a potential that is screened by an effective electron cloud around colliding nuclei (extended Salpeter ion-sphere model). We calculate the mean field screened Coulomb potentials for atomic nuclei with equal and nonequal charges, appropriate astrophysical S factors, and enhancement factors of reaction rates. As a byproduct, we study analytic behavior of the screening potential at small separations between the reactants. In this model, astrophysical S factors depend not only on nuclear physics but on plasma screening as well. The enhancement factors are in good agreement with calculations by other methods. This allows us to formulate the combined, pure analytic model of strong plasma screening in thermonuclear reactions. The results can be useful for simulating nuclear burning in white dwarfs and neutron stars.

  5. Strong plasma screening in thermonuclear reactions: Electron drop model

    E-Print Network [OSTI]

    P. A. Kravchuk; D. G. Yakovlev

    2014-01-11T23:59:59.000Z

    We analyze enhancement of thermonuclear fusion reactions due to strong plasma screening in dense matter using a simple electron drop model. The model assumes fusion in a potential that is screened by an effective electron cloud around colliding nuclei (extended Salpeter ion-sphere model). We calculate the mean field screened Coulomb potentials for atomic nuclei with equal and nonequal charges, appropriate astrophysical S factors, and enhancement factors of reaction rates. As a byproduct, we study analytic behavior of the screening potential at small separations between the reactants. In this model, astrophysical S factors depend not only on nuclear physics but on plasma screening as well. The enhancement factors are in good agreement with calculations by other methods. This allows us to formulate the combined, pure analytic model of strong plasma screening in thermonuclear reactions. The results can be useful for simulating nuclear burning in white dwarfs and neutron stars.

  6. Method of achieving the controlled release of thermonuclear energy

    DOE Patents [OSTI]

    Brueckner, Keith A. (Ann Arbor, MI)

    1986-01-01T23:59:59.000Z

    A method of achieving the controlled release of thermonuclear energy by illuminating a minute, solid density, hollow shell of a mixture of material such as deuterium and tritium with a high intensity, uniformly converging laser wave to effect an extremely rapid build-up of energy in inwardly traveling shock waves to implode the shell creating thermonuclear conditions causing a reaction of deuterons and tritons and a resultant high energy thermonuclear burn. Utilizing the resulting energy as a thermal source and to breed tritium or plutonium. The invention also contemplates a laser source wherein the flux level is increased with time to reduce the initial shock heating of fuel and provide maximum compression after implosion; and, in addition, computations and an equation are provided to enable the selection of a design having a high degree of stability and a dependable fusion performance by establishing a proper relationship between the laser energy input and the size and character of the selected material for the fusion capsule.

  7. Relativistic outflow from two thermonuclear shell flashes on neutron stars

    E-Print Network [OSTI]

    Zand, Jean in 't; Cavecchi, Yuri

    2014-01-01T23:59:59.000Z

    We study the exceptionally short (32-41 ms) precursors of two intermediate-duration thermonuclear X-ray bursts observed with RXTE from the neutron stars in 4U 0614+09 and 2S 0918-549. They exhibit photon fluxes that surpass those at the Eddington limit later in the burst by factors of 2.6 to 3.1. We are able to explain both the short duration and the super-Eddington flux by mildly relativistic outflow velocities of 0.1$c$ to 0.3$c$ subsequent to the thermonuclear shell flashes on the neutron stars. These are the highest velocities ever measured from any thermonuclear flash. The precursor rise times are also exceptionally short: about 1 ms. This is inconsistent with predictions for nuclear flames spreading laterally as deflagrations and suggests detonations instead. This is the first time that a detonation is suggested for such a shallow ignition column depth ($y_{\\rm ign}$ = 10$^{10}$ g cm$^{-2}$). The detonation would possibly require a faster nuclear reaction chain, such as bypassing the alpha-capture on $^...

  8. English home Forum Photo Gallery Features Newsletter Archive About US Help Site Map languages Culture/Life

    E-Print Network [OSTI]

    to build its own thermonuclear experimental reactor A leading Chinese plasma physicist said Thursday China might build its own thermonuclear experimental reactor, which would be expected to supply sustained in thermonuclear reaction, Chinese scientists have already participated in the International Thermonuclear

  9. Brussels advocates a lone rider for ITER 09/22/2004 Edition

    E-Print Network [OSTI]

    can advance alone to establish the thermonuclear reactor experimental ITER in Cadarache. France in the construction of the future experimental thermonuclear reactor ITER, if Brussels does not manage to convince

  10. A meeting is planned Tuesday

    E-Print Network [OSTI]

    Thermonuclear Experimental Reactor (ITER) -- a test bed for what is being billed as a safe and inexhaustible | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Google It: International Thermonuclear Spokesman Fabio Fabbi Questions Eu Optimism Experimental Reactor

  11. Extension of thermonuclear functions through the pathway model including Maxwell-Boltzmann and Tsallis distributions

    E-Print Network [OSTI]

    H. J. Haubold; D. Kumar

    2007-08-16T23:59:59.000Z

    The Maxwell-Boltzmannian approach to nuclear reaction rate theory is extended to cover Tsallis statistics (Tsallis, 1988) and more general cases of distribution functions. An analytical study of respective thermonuclear functions is being conducted with the help of statistical techniques. The pathway model, recently introduced by Mathai (2005), is utilized for thermonuclear functions and closed-form representations are obtained in terms of H-functions and G-functions. Maxwell-Boltzmannian thermonuclear functions become particular cases of the extended thermonuclear functions. A brief review on the development of the theory of analytic representations of nuclear reaction rates is given.

  12. An experimental system for the n-butyl-lithium initiated polymerization of styrene in a multi-sampled batch reactor

    E-Print Network [OSTI]

    Cox, James Harvey

    1974-01-01T23:59:59.000Z

    temperature gradients and thereby causing concentration gradients due to increased reaction rates. No method has yet been reported for monitoring the internal temperature of such a soft-drink bottle reactor, or of providing any kind of dy- namic... and Bywater [I] showed that the initial rate of heat generation by the polymerization reac- tion would be so high that the thermal resistance of the reactor bowl would prevent isothermal operations. By using the manufacturer's stainless steel internal...

  13. U.S. Department of Energy Office of Inspector General Annual...

    Broader source: Energy.gov (indexed) [DOE]

    Carbon Fiber Technology Center The Department of Energy's International Thermonuclear Experimental Reactor (ITER) Responsibilities Depleted Uranium Operations at...

  14. Thermonuclear Explosions of Chandrasekhar-Mass White Dwarfs

    E-Print Network [OSTI]

    W. Hillebrandt; M. Reinecke; J. C. Niemeyer

    2000-05-16T23:59:59.000Z

    We present a new way of modeling turbulent thermonuclear deflagration fronts in Chandrasekhar-mass white dwarfs, consisting of carbon and oxygen, undergoing a type Ia supernova explosion. Our approach is a front capturing/tracking hybrid scheme, based on a level set method, which treats the front as a mathematical discontinuity and allows for full coupling between the front geometry and the flow field. First results of the method applied to the problem of type Ia supernovae are discussed. It will be shown that even in 2-D and even with a physically motivated sub-grid model numerically ``converged'' results are difficult to obtain.

  15. Accepted Manuscript Making Tungsten Work

    E-Print Network [OSTI]

    Raffray, A. René

    Thermonuclear Experimental Reactor Organization, Cadarache, FRANCE 3 Plasma Science and Fusion Center at MIT International Thermonuclear Experimental Reactor Organization, Cadarache, FRANCE 3 Plasma Science and Fusion Thermonuclear Experimental Reactor). Tungsten (W) is the plasma-facing material of choice in several design

  16. Simulations of Turbulent Thermonuclear Burning in Type Ia Supernovae

    E-Print Network [OSTI]

    W. Hillebrandt; M. Reinecke; W. Schmidt; F. K. Roepke; C. Travaglio; J. C. Niemeyer

    2004-05-11T23:59:59.000Z

    Type Ia supernovae have recently received considerable attention because it appears that they can be used as "standard candles" to measure cosmic distances out to billions of light years away from us. Observations of type Ia supernovae seem to indicate that we are living in a universe that started to accelerate its expansion when it was about half its present age. These conclusions rest primarily on phenomenological models which, however, lack proper theoretical understanding, mainly because the explosion process, initiated by thermonuclear fusion of carbon and oxygen into heavier elements, is difficult to simulate even on supercomputers. Here, we investigate a new way of modeling turbulent thermonuclear deflagration fronts in white dwarfs undergoing a type Ia supernova explosion. Our approach is based on a level set method which treats the front as a mathematical discontinuity and allows for full coupling between the front geometry and the flow field. New results of the method applied to the problem of type Ia supernovae are obtained. It is shown that in 2-D with high spatial resolution and a physically motivated subgrid scale model for the nuclear flames numerically "converged" results can be obtained, but for most initial conditions the stars do not explode. In contrast, simulations in 3-D, do give the desired explosions and many of their properties, such as the explosion energies, lightcurves and nucleosynthesis products, are in very good agreement with observed type Ia supernovae.

  17. On the Evolution of Thermonuclear Flames on Large Scales

    E-Print Network [OSTI]

    Ju Zhang; O. E. Bronson Messer; Alexei M. Khokhlov; Tomasz Plewa

    2006-10-05T23:59:59.000Z

    The thermonuclear explosion of a massive white dwarf in a Type Ia supernova explosion is characterized by vastly disparate spatial and temporal scales. The extreme dynamic range inherent to the problem prevents the use of direct numerical simulation and forces modelers to resort to subgrid models to describe physical processes taking place on unresolved scales. We consider the evolution of a model thermonuclear flame in a constant gravitational field on a periodic domain. The gravitational acceleration is aligned with the overall direction of the flame propagation, making the flame surface subject to the Rayleigh-Taylor instability. The flame evolution is followed through an extended initial transient phase well into the steady-state regime. The properties of the evolution of flame surface are examined. We confirm the form of the governing equation of the evolution suggested by Khokhlov (1995). The mechanism of vorticity production and the interaction between vortices and the flame surface are discussed. The results of our investigation provide the bases for revising and extending previous subgrid-scale model.

  18. Thermonuclear supernova models, and observations of Type Ia supernovae

    E-Print Network [OSTI]

    E. Bravo; C. Badenes; D. Garcia-Senz

    2004-12-07T23:59:59.000Z

    In this paper, we review the present state of theoretical models of thermonuclear supernovae, and compare their predicitions with the constraints derived from observations of Type Ia supernovae. The diversity of explosion mechanisms usually found in one-dimensional simulations is a direct consequence of the impossibility to resolve the flame structure under the assumption of spherical symmetry. Spherically symmetric models have been successful in explaining many of the observational features of Type Ia supernovae, but they rely on two kinds of empirical models: one that describes the behaviour of the flame on the scales unresolved by the code, and another that takes account of the evolution of the flame shape. In contrast, three-dimensional simulations are able to compute the flame shape in a self-consistent way, but they still need a model for the propagation of the flame in the scales unresolved by the code. Furthermore, in three dimensions the number of degrees of freedom of the initial configuration of the white dwarf at runaway is much larger than in one dimension. Recent simulations have shown that the sensitivity of the explosion output to the initial conditions can be extremely large. New paradigms of thermonuclear supernovae have emerged from this situation, as the Pulsating Reverse Detonation. The resolution of all these issues must rely on the predictions of observational properties of the models, and their comparison with current Type Ia supernova data, including X-ray spectra of Type Ia supernova remnants.

  19. Faint Thermonuclear Supernovae from AM Canum Venaticorum Binaries

    E-Print Network [OSTI]

    Lars Bildsten; Ken J. Shen; Nevin N. Weinberg; Gijs Nelemans

    2007-05-06T23:59:59.000Z

    Helium that accretes onto a Carbon/Oxygen white dwarf in the double white dwarf AM Canum Venaticorum (AM CVn) binaries undergoes unstable thermonuclear flashes when the orbital period is in the 3.5-25 minute range. At the shortest orbital periods (and highest accretion rates, Mdot > 10^-7 Msol/yr), the flashes are weak and likely lead to the Helium equivalent of classical nova outbursts. However, as the orbit widens and Mdot drops, the mass required for the unstable ignition increases, leading to progressively more violent flashes up to a final flash with Helium shell mass ~ 0.02-0.1 Msol. The high pressures of these last flashes allow the burning to produce the radioactive elements 48Cr, 52Fe, and 56Ni that power a faint (M_V in the range of -15 to -18) and rapidly rising (few days) thermonuclear supernova. Current galactic AM CVn space densities imply one such explosion every 5,000-15,000 years in 10^11 Msol of old stars (~ 2-6% of the Type Ia rate in E/SO galaxies). These ".Ia" supernovae (one-tenth as bright for one-tenth the time as a Type Ia supernovae) are excellent targets for deep (e.g. V=24) searches with nightly cadences, potentially yielding an all-sky rate of 1,000 per year.

  20. Cosmic and Galactic Neutrino Backgrounds from Thermonuclear Sources

    E-Print Network [OSTI]

    Cristiano Porciani; Silvia Petroni; Giovanni Fiorentini

    2003-11-20T23:59:59.000Z

    We estimate energy spectra and fluxes at the Earth's surface of the cosmic and Galactic neutrino backgrounds produced by thermonuclear reactions in stars. The extra-galactic component is obtained by combining the most recent estimates of the cosmic star formation history and the stellar initial mass function with accurate theoretical predictions of the neutrino yields all over the thermonuclear lifetime of stars of different masses. Models of the structure and evolution of the Milky Way are used to derive maps of the expected flux generated by Galactic sources as a function of sky direction. The predicted neutrino backgrounds depend only slightly on model parameters. In the relevant 50 keV-10 MeV window, the total flux of cosmic neutrinos ranges between 20 and 65 particles per square cm per s. Neutrinos reaching the Earth today have been typically emitted at redshift z~2. Their energy spectrum peaks at E~0.1-0.3 MeV. The energy and entropy densities of the cosmic background are negligible with respect to the thermal contribution of relic neutrinos originated in the early universe. In every sky direction, the cosmic background is outnumbered by the Galactic one, whose integrated flux amounts to 300-1000 particles per square cm per s. The emission from stars in the Galactic disk contributes more than 95 per cent of the signal.

  1. A time-delay approach for the modeling and control of plasma instabilities in thermonuclear fusion

    E-Print Network [OSTI]

    Sipahi, Rifat

    for thermonuclear fusion plasmas. Indeed, advanced plasma confinement scenarios, such as the ones considered1 A time-delay approach for the modeling and control of plasma instabilities in thermonuclear fusion Emmanuel WITRANT, Erik OLOFSSON, Silviu-Iulian NICULESCU, March 13, 2009. Abstract This letter

  2. On the thermonuclear runaway in Type Ia supernovae: How to run away

    E-Print Network [OSTI]

    P. Höflich; J. Stein

    2002-01-01T23:59:59.000Z

    Type Ia Supernovae are thought to be thermonuclear explosions of massive white dwarfs (WD). We present the first study of multi-dimensional effects during the final hours prior to the thermonuclear runaway which leads to the explosion. The calculations utilize an implicit, 2-D hydrodynamical code

  3. Astrophysical Thermonuclear Functions for Boltzmann-Gibbs Statistics and Tsallis Statistics

    E-Print Network [OSTI]

    R. K. Saxena; A. M. Mathai; H. J. Haubold

    2004-06-22T23:59:59.000Z

    We present an analytic proof of the integrals for astrophysical thermonuclear functions which are derived on the basis of Boltzmann-Gibbs statistical mechanics. Among the four different cases of astrophysical thermonuclear functions, those with a depleted high-energy tail and a cut-off at high energies find a natural interpretation in q-statistics.

  4. A Systematic Approach to the Design of a Large Scale Detritiation System for Controlled Thermonuclear Fusion Experiments

    E-Print Network [OSTI]

    A Systematic Approach to the Design of a Large Scale Detritiation System for Controlled Thermonuclear Fusion Experiments

  5. Thermonuclear rates of the 28Si(p, y) reaction M. Kicinska-Habior and T. Matulewicz

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1881 Thermonuclear rates of the 28Si(p, y) reaction M. Kicinska-Habior and T. Matulewicz Institute Thermonuclear reaction rates NA av > are the quan- tities of essential importance for models of stellar in a much more extended energy range. The thermonuclear rates of the 28Si(p, y) reaction, although it does

  6. Tidally-induced thermonuclear Supernovae Stephan Rosswog1, Enrico Ramirez-Ruiz2, W. Raphael Hix3

    E-Print Network [OSTI]

    Rosswog, Stephan

    Tidally-induced thermonuclear Supernovae Stephan Rosswog1, Enrico Ramirez-Ruiz2, W. Raphael Hix3 1 in a thermonuclear explosion. These explosions are not restricted to progenitor masses close to the Chandrasekhar thermonuclear supernova together with an X-ray flare thus whistle-blows the existence of such moderate

  7. State of Advancement of the International REVE Project: Computational Modelling of Irradiation-Induced Hardening in Reactor Pressure Vessel Steels and Relevant Experimental Validation Programme

    SciTech Connect (OSTI)

    Malerba, Lorenzo; Van Walle, Eric [SCK.CEN, Boeretang 200, 2400 Mol (Belgium); Domain, Christophe; Jumel, Stephanie; Van Duysen, Jean-Claude [EDR R and D (France)

    2002-07-01T23:59:59.000Z

    The REVE (Reactor for Virtual Experiments) project is an international joint effort aimed at developing multi-scale modelling computational toolboxes capable of simulating the behaviour of materials under irradiation at different time and length scales. Well grounded numerical techniques such as molecular dynamics (MD) and Monte Carlo (MC) algorithms, as well as rate equation (RE) and dislocation-defect interaction theory, form the basis on which the project is built. The goal is to put together a suite of integrated codes capable of deducing the changes in macroscopic properties starting from a detailed simulation of the microstructural changes produced by irradiation in materials. To achieve this objective, several European laboratories are closely collaborating, while exchanging data with American and Japanese laboratories currently pursuing similar approaches. The material chosen for the first phase of this project is reactor pressure vessel (RPV) steel, the target macroscopic magnitude to be predicted being the yield strength increase ({delta}{sigma}y) due, essentially, to irradiation-enhanced formation of intragranular solute atom precipitates or clouds, as well as irradiation induced defects in the matrix, such as point defect clusters and dislocation loops. A description of the methodological approach used in the project and its current state is given in the paper. The development of the simulation tools requires a continuous feedback from ad hoc experimental data. In the framework of the REVE project SCK EN has therefore performed a neutron irradiation campaign of model alloys of growing complexity (from pure Fe to binary and ternary systems and a real RPV steel) in the Belgian test reactor BR2 and is currently carrying on the subsequent materials characterisation using its hot cell facilities. The paper gives the details of this experimental programme - probably the first large-scale one devoted to the validation of numerical simulation tools - and presents and discusses the first available results, with a view to their use as feedback for the improvement of the computational modelling. (authors)

  8. Composite Materials under Extreme Radiation and Temperature Environments of the Next Generation Nuclear Reactors

    SciTech Connect (OSTI)

    Simos, N.

    2011-05-01T23:59:59.000Z

    In the nuclear energy renaissance, driven by fission reactor concepts utilizing very high temperatures and fast neutron spectra, materials with enhanced performance that exceeds are expected to play a central role. With the operating temperatures of the Generation III reactors bringing the classical reactor materials close to their performance limits there is an urgent need to develop and qualify new alloys and composites. Efforts have been focused on the intricate relations and the high demands placed on materials at the anticipated extreme states within the next generation fusion and fission reactors which combine high radiation fluxes, elevated temperatures and aggressive environments. While nuclear reactors have been in operation for several decades, the structural materials associated with the next generation options need to endure much higher temperatures (1200 C), higher neutron doses (tens of displacements per atom, dpa), and extremely corrosive environments, which are beyond the experience on materials accumulated to-date. The most important consideration is the performance and reliability of structural materials for both in-core and out-of-core functions. While there exists a great body of nuclear materials research and operating experience/performance from fission reactors where epithermal and thermal neutrons interact with materials and alter their physio-mechanical properties, a process that is well understood by now, there are no operating or even experimental facilities that will facilitate the extreme conditions of flux and temperature anticipated and thus provide insights into the behaviour of these well understood materials. Materials, however, still need to be developed and their interaction and damage potential or lifetime to be quantified for the next generation nuclear energy. Based on material development advances, composites, and in particular ceramic composites, seem to inherently possess properties suitable for key functions within the operating envelope of both fission and fusion reactors. In advanced fission reactors composite materials are being designed in an effort to extend the life and improve the reliability of fuel rod cladding as well as structural materials. Composites are being considered for use as core internals in the next generation of gas-cooled reactors. Further, next-generation plasma-fusion reactors, such as the International Thermonuclear Experimental Reactor (ITER) will rely on the capabilities of advanced composites to safely withstand extremely high neutron fluxes while providing superior thermal shock resistance.

  9. On the stability of thermonuclear shell sources in stars

    E-Print Network [OSTI]

    S. -C. Yoon; N. Langer; M. van der Sluys

    2004-06-07T23:59:59.000Z

    We present a quantitative criterion for the thermal stability of thermonuclear shell sources. We find the thermal stability of shell sources to depend on exactly three factors: they are more stable when they are geometrically thicker, less degenerate and hotter. This confirms and unifies previously obtained results in terms of the geometry, temperature and density of the shell source, by a simplified but quantitative approach to the physics of shell nuclear burning. We present instability diagrams in the temperature-density plane for hydrogen and helium shell burning, which allow a simple evaluation of the stability conditions of such shell sources in stellar models. The performance of our stability criterion is demonstrated in various numerical models: in a 3 Msun AGB star, in helium accreting CO white dwarfs, in a helium white dwarf which is covered by a thin hydrogen envelope, and in a 1.0 Msun giant.

  10. The Periods Discovered by RXTE in Thermonuclear Flash Bursts

    E-Print Network [OSTI]

    T. E. Strohmayer; J. H. Swank; W. Zhang

    1998-01-23T23:59:59.000Z

    Oscillations in the X-ray flux of thermonuclear X-ray bursts have been observed with RXTE from at least 6 low-mass binaries, at frequencies from 330 Hz to 589 Hz. There appear to be preferred relations between the frequencies present during the bursts and those seen in the persistent flux. The amplitude of the oscillations can exceed 50 % near burst onset. Except for a systematic increase in oscillation frequency as the burst progresses, the frequency is stable. Time resolved spectra track increases in the X-ray emitting area due to propagation of the burning front over the neutron star surface, as well as radiation driven expansion of the photosphere. The neutron star mass, radius, and distance can be inferred when spectra are compared to theoretical expectations.

  11. Screening in Thermonuclear Reaction Rates in the Sun

    E-Print Network [OSTI]

    Andrei V. Gruzinov; John N. Bahcall

    1998-01-20T23:59:59.000Z

    We evaluate the effect of electrostatic screening by ions and electrons on low-Z thermonuclear reactions in the sun. We use a mean field formalism and calculate the electron density of the screening cloud using the appropriate density matrix equation of quantum statistical mechanics. Because of well understood physical effects that are included for the first time in our treatment, the calculated enhancement of reaction rates does not agree with the frequently used interpolation formulae. Our result does agree, within small uncertainties, with Salpeter's weak screening formula. If weak screening is used instead of the commonly employed screening prescription of Graboske et al., the predicted $^8$B neutrino flux is increased by 7% and the predicted chlorine rate is increased by 0.4 SNU.

  12. A Study and Comparison of SCR Reaction Kinetics from Reactor...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    A Study and Comparison of SCR Reaction Kinetics from Reactor and Engine Experimental Data A Study and Comparison of SCR Reaction Kinetics from Reactor and Engine Experimental Data...

  13. Measurement of neutron capture on 50Ti at thermonuclear energies

    E-Print Network [OSTI]

    P. V. Sedyshev; P. Mohr; H. Beer; H. Oberhummer; Yu. P. Popov; W. Rochow

    1999-07-28T23:59:59.000Z

    At the Karlsruhe and Tuebingen 3.75 MV Van de Graaff accelerators the thermonuclear 50Ti(n,gamma)51Ti(5.8 min) cross section was measured by the fast cyclic activation technique via the 320.852 and 928.65 keV gamma-ray lines of the 51Ti-decay. Metallic Ti samples of natural isotopic composition and samples of TiO2 enriched in 50Ti by 67.53 % were irradiated between two gold foils which served as capture standards. The capture cross-section was measured at the neutron energies 25, 30, 52, and 145 keV, respectively. The direct capture cross section was determined to be 0.387 +/- 0.011 mbarn at 30 keV. We found evidence for a bound state s-wave resonance with an estimated radiative width of 0.34 eV which destructively interfers with direct capture. The strength of a suggested s-wave resonance at 146.8 keV was determined. The present data served to calculate, in addition to the directly measured Maxwellian averaged capture cross sections at 25 and 52 keV, an improved stellar 50Ti(n,gamma)51Ti rate in the thermonuclear energy region from 1 to 250 keV. The new stellar rate leads at low temperatures to much higher values than the previously recommended rate, e.g., at kT=8 keV the increase amounts to about 50 %. The new reaction rate therefore reduces the abundance of 50Ti due to s-processing in AGB stars.

  14. Detonating Failed Deflagration Model of Thermonuclear Supernovae I. Explosion Dynamics

    E-Print Network [OSTI]

    Tomasz Plewa

    2006-11-24T23:59:59.000Z

    We present a detonating failed deflagration model of Type Ia supernovae. In this model, the thermonuclear explosion of a massive white dwarf follows an off-center deflagration. We conduct a survey of asymmetric ignition configurations initiated at various distances from the stellar center. In all cases studied, we find that only a small amount of stellar fuel is consumed during deflagration phase, no explosion is obtained, and the released energy is mostly wasted on expanding the progenitor. Products of the failed deflagration quickly reach the stellar surface, polluting and strongly disturbing it. These disturbances eventually evolve into small and isolated shock-dominated regions which are rich in fuel. We consider these regions as seeds capable of forming self-sustained detonations that, ultimately, result in the thermonuclear supernova explosion. Preliminary nucleosynthesis results indicate the model supernova ejecta are typically composed of about 0.1-0.25 Msun of silicon group elements, 0.9-1.2 Msun of iron group elements, and are essentially carbon-free. The ejecta have a composite morphology, are chemically stratified, and display a modest amount of intrinsic asymmetry. The innermost layers are slightly egg-shaped with the axis ratio ~1.2-1.3 and dominated by the products of silicon burning. This central region is surrounded by a shell of silicon-group elements. The outermost layers of ejecta are highly inhomogeneous and contain products of incomplete oxygen burning with only small admixture of unburned stellar material. The explosion energies are ~1.3-1.5 10^51 erg.

  15. Energy limits on runaway electrons in tokamak plasmas J. R. Martin-Solisa)

    E-Print Network [OSTI]

    Martín-Solís, José Ramón

    runaway electrons in JET and the projected International Thermonuclear Experimental Reactor ITER ITER EDA International Thermonuclear Experi- mental Reactor ITER 1 where larger amounts of runaway electrons than those

  16. Experimental study of curved guide tubes for pellet injection

    SciTech Connect (OSTI)

    Combs, S.K.; Baylor, L.R.; Foust, C.R.; Gouge, M.J.; Jernigan, T.C.; Milora, S.L.

    1997-12-01T23:59:59.000Z

    The use of curved guide tubes for transporting frozen hydrogen pellets offers great flexibility for pellet injection into plasma devices. While this technique has been previously employed, an increased interest in its applicability has been generated with the recent ASDEX Upgrade experimental data for magnetic high-field side (HFS) pellet injection. In these innovative experiments, the pellet penetration appeared to be significantly deeper than for the standard magnetic low-field side injection scheme, along with corresponding greater fueling efficiencies. Thus, some of the major experimental fusion devices are planning experiments with HFS pellet injection. Because of the complex geometries of experimental fusion devices, installations with multiple curved guide tube sections will be required for HFS pellet injection. To more thoroughly understand and document the capability of curved guide tubes, an experimental study is under way at the Oak Ridge National Laboratory (ORNL). In particular, configurations and pellet parameters applicable for the DIII-D tokamak and the International Thermonuclear Experimental Reactor (ITER) were simulated in laboratory experiments. Initial test results with nominal 2.7- and 10-mm-diam deuterium pellets are presented and discussed.

  17. Repair welding of fusion reactor components. Final technical report

    SciTech Connect (OSTI)

    Chin, B.A.; Wang, C.A.

    1997-09-30T23:59:59.000Z

    The exposure of metallic materials, such as structural components of the first wall and blanket of a fusion reactor, to neutron irradiation will induce changes in both the material composition and microstructure. Along with these changes can come a corresponding deterioration in mechanical properties resulting in premature failure. It is, therefore, essential to expect that the repair and replacement of the degraded components will be necessary. Such repairs may require the joining of irradiated materials through the use of fusion welding processes. The present ITER (International Thermonuclear Experimental Reactor) conceptual design is anticipated to have about 5 km of longitudinal welds and ten thousand pipe butt welds in the blanket structure. A recent study by Buende et al. predict that a failure is most likely to occur in a weld. The study is based on data from other large structures, particularly nuclear reactors. The data used also appear to be consistent with the operating experience of the Fast Flux Test Facility (FFTF). This reactor has a fuel pin area comparable with the area of the ITER first wall and has experienced one unanticipated fuel pin failure after two years of operation. The repair of irradiated structures using fusion welding will be difficult due to the entrapped helium. Due to its extremely low solubility in metals, helium will diffuse and agglomerate to form helium bubbles after being trapped at point defects, dislocations, and grain boundaries. Welding of neutron-irradiated type 304 stainless steels has been reported with varying degree of heat-affected zone cracking (HAZ). The objectives of this study were to determine the threshold helium concentrations required to cause HAZ cracking and to investigate techniques that might be used to eliminate the HAZ cracking in welding of helium-containing materials.

  18. Design of an experimental loop for post-LOCA heat transfer regimes in a Gas-cooled Fast Reactor

    E-Print Network [OSTI]

    Cochran, Peter A. (Peter Andrew)

    2005-01-01T23:59:59.000Z

    The goal of this thesis is to design an experimental thermal-hydraulic loop capable of generating accurate, reliable data in various convection heat transfer regimes for use in the formulation of a comprehensive convection ...

  19. 11/21/2006 07:40 AMITAR-TASS Page 1 of 2http://www.itar-tass.com/eng/prnt.html?NewsID=11003725

    E-Print Network [OSTI]

    by means of thermonuclear fusion at new power plants. The total cost of the project, in which approximately thermonuclear experimental reactor (ITER) was signed at the Elysee Palace here on Tuesday. Representatives the thermonuclear synthesis and had carried out a broad range of experimental works on "Tokamak" thermonuclear

  20. A bright thermonuclear X-ray burst simultaneously observed with Chandra and RXTE

    E-Print Network [OSTI]

    in ’t Zand, J. J. M.

    The prototypical accretion-powered millisecond pulsar SAX J1808.4?3658 was observed simultaneously with Chandra-LETGS and RXTE-PCA near the peak of a transient outburst in November 2011. A single thermonuclear (type-I) ...

  1. Plasma-material Interactions in Current Tokamaks and their Implications for Next-step Fusion Reactors

    SciTech Connect (OSTI)

    Federici, G.; Skinner, C.H.; Brooks, J.N.; Coad, J.P.; Grisolia, C. [and others

    2001-01-10T23:59:59.000Z

    The major increase in discharge duration and plasma energy in a next-step DT [deuterium-tritium] fusion reactor will give rise to important plasma-material effects that will critically influence its operation, safety, and performance. Erosion will increase to a scale of several centimeters from being barely measurable at a micron scale in today's tokamaks. Tritium co-deposited with carbon will strongly affect the operation of machines with carbon plasma-facing components. Controlling plasma wall interactions is critical to achieving high performance in present-day tokamaks and this is likely to continue to be the case in the approach to practical fusion reactors. Recognition of the important consequences of these phenomena has stimulated an internationally coordinated effort in the field of plasma-surface interactions supporting the Engineering Design Activities of the International Thermonuclear Experimental Reactor (ITER) project and significant progress has been made in better under standing these issues. This paper reviews the underlying physical processes and the existing experimental database of plasma-material interactions both in tokamaks and laboratory simulation facilities for conditions of direct relevance to next-step fusion reactors. Two main topical groups of interactions are considered: (i) erosion/redeposition from plasma sputtering and disruptions, including dust and flake generation, (ii) tritium retention and removal. The use of modeling tools to interpret the experimental results and make projections for conditions expected in future devices is explained. Outstanding technical issues and specific recommendations on potential R and D [Research and Development] avenues for their resolution are presented.

  2. Three-dimensional neutronics optimization of helium-cooled blanket for multi-functional experimental fusion-fission hybrid reactor (FDS-MFX)

    SciTech Connect (OSTI)

    Jiang, J.; Yuan, B.; Jin, M.; Wang, M.; Long, P.; Hu, L. [Inst. of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Univ. of Science and Technology of China, Hefei, Anhui, 230031 (China); School of Nuclear Science and Technology, Univ. of Science and Technology of China, No.350 Shushanhu Road, Shushan District, Hefei, Anhui, 230031 (China)

    2012-07-01T23:59:59.000Z

    Three-dimensional neutronics optimization calculations were performed to analyse the parameters of Tritium Breeding Ratio (TBR) and maximum average Power Density (PDmax) in a helium-cooled multi-functional experimental fusion-fission hybrid reactor named FDS (Fusion-Driven hybrid System)-MFX (Multi-Functional experimental) blanket. Three-stage tests will be carried out successively, in which the tritium breeding blanket, uranium-fueled blanket and spent-fuel-fueled blanket will be utilized respectively. In this contribution, the most significant and main goal of the FDS-MFX blanket is to achieve the PDmax of about 100 MW/m3 with self-sustaining tritium (TBR {>=} 1.05) based on the second-stage test with uranium-fueled blanket to check and validate the demonstrator reactor blanket relevant technologies based on the viable fusion and fission technologies. Four different enriched uranium materials were taken into account to evaluate PDmax in subcritical blanket: (i) natural uranium, (ii) 3.2% enriched uranium, (iii) 19.75% enriched uranium, and (iv) 64.4% enriched uranium carbide. These calculations and analyses were performed using a home-developed code VisualBUS and Hybrid Evaluated Nuclear Data Library (HENDL). The results showed that the performance of the blanket loaded with 64.4% enriched uranium was the most attractive and it could be promising to effectively obtain tritium self-sufficiency (TBR-1.05) and a high maximum average power density ({approx}100 MW/m{sup 3}) when the blanket was loaded with the mass of {sup 235}U about 1 ton. (authors)

  3. Reaction Rate and Composition Dependence of the Stability of Thermonuclear Burning on Accreting Neutron Stars

    E-Print Network [OSTI]

    Keek, L; Heger, A

    2014-01-01T23:59:59.000Z

    The stability of thermonuclear burning of hydrogen and helium accreted onto neutron stars is strongly dependent on the mass accretion rate. The burning behavior is observed to change from Type I X-ray bursts to stable burning, with oscillatory burning occurring at the transition. Simulations predict the transition at a ten times higher mass accretion rate than observed. Using numerical models we investigate how the transition depends on the hydrogen, helium, and CNO mass fractions of the accreted material, as well as on the nuclear reaction rates of triple alpha and the hot-CNO breakout reactions 15O(a,g)19Ne and 18Ne(a,p)21Na. For a lower hydrogen content the transition is at higher accretion rates. Furthermore, most experimentally allowed reaction rate variations change the transition accretion rate by at most 10%. A factor ten decrease of the 15O(a,g)19Ne rate, however, produces an increase of the transition accretion rate of 35%. None of our models reproduce the transition at the observed rate, and depend...

  4. Struct Multidisc Optim (2006) 32: 473484 DOI 10.1007/s00158-006-0022-1

    E-Print Network [OSTI]

    Vel, Senthil

    2006-01-01T23:59:59.000Z

    for fusion reactors, and in critical engine components, such as intake and exhaust valves. Several studies investigated for plasma facing components of the International Thermonuclear Experimental Reactor (Ueda

  5. Experimental Investigation on the Effects of Coolant Concentration on Sub-Cooled Boiling and Crud Deposition on Reactor Cladding at Prototypical PWR Operating Conditions

    SciTech Connect (OSTI)

    Schultis, J., Kenneth; Fenton, Donald, L.

    2006-10-20T23:59:59.000Z

    Increasing demand for energy necessitates nuclear power units to increase power limits. This implies significant changes in the design of the core of the nuclear power units, therefore providing better performance and safety in operations. A major hindrance to the increase of nuclear reactor performance especially in Pressurized Deionized water Reactors (PWR) is Axial Offset Anomaly (AOA)--the unexpected change in the core axial power distribution during operation from the predicted distribution. This problem is thought to be occur because of precipitation and deposition of lithiated compounds like boric acid (H{sub 2}BO{sub 3}) and lithium metaborate (LiBO{sub 2}) on the fuel rod cladding. Deposited boron absorbs neutrons thereby affecting the total power distribution inside the reactor. AOA is thought to occur when there is sufficient build-up of crud deposits on the cladding during subcooled nucleate boiling. Predicting AOA is difficult as there is very little information regarding the heat and mass transfer during subcooled nucleate boiling. An experimental investigation was conducted to study the heat transfer characteristics during subcooled nucleate boiling at prototypical PWR conditions. Pool boiling tests were conducted with varying concentrations of lithium metaborate (LiBO{sub 2}) and boric acid (H{sub 2}BO{sub 3}) solutions in deionized water. The experimental data collected includes the effect of coolant concentration, subcooling, system pressure and heat flux on pool the boiling heat transfer coefficient. The analysis of particulate deposits formed on the fuel cladding surface during subcooled nucleate boiling was also performed. The results indicate that the pool boiling heat transfer coefficient degrades in the presence of boric acid and lithium metaborate compared to pure deionized water due to lesser nucleation. The pool boiling heat transfer coefficients decreased by about 24% for 5000 ppm concentrated boric acid solution and by 27% for 5000 ppm lithium metaborate solution respectively at the saturation temperature for 1000 psi (68.9 bar) coolant pressure. Boiling tests also revealed the formation of fine deposits of boron and lithium on the cladding surface which degraded the heat transfer rates. The boron and lithium metaborate precipitates after a 5 day test at 5000 ppm concentration and 1000 psi (68.9 bar) operating pressure reduced the heat transfer rate 21% and 30%, respectively for the two solutions.

  6. Nucleosynthesis in type Ia supernovae driven by asymmetric thermonuclear ignition

    SciTech Connect (OSTI)

    Maeda, Keiichi [Institute for the Physics and Mathematics of the Universe (IPMU), Todai Institutes for Advanced Study (TODIAS), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)

    2012-11-12T23:59:59.000Z

    Type Ia Supernovae (SNe Ia) are believed to be thermonuclear explosions of a white dwarf. They can be used as mature cosmological standardized candles, leading to the discovery of the accelerating expansion of the Universe. However, the explosion mechanism has not yet been fully clarified. In this paper, we first present nucleosynthetic features of a leading explosion scenario, namely a delayed-detonation scenario. Based on this, we propose a new and strong observational constraint on the explosion mechanism through emission lines from neutron-rich Fe-peaks. Especially, we show that an asymmetry in the explosion is likely a generic feature. We further argue that the diversity arising from various viewing angles can be an origin of observational diversities of SNe Ia seen in their spectral features (suspected possible biases in cosmology) and colors (related to the extinction estimate in cosmology). Using these new insights could open up a possibility of using SNe Ia as more precise distance indicators than currently employed.

  7. The cooling rate of neutron stars after thermonuclear shell flashes

    E-Print Network [OSTI]

    Zand, J J M in 't; Triemstra, T L; Mateijsen, R A D A; Bagnoli, T

    2013-01-01T23:59:59.000Z

    Thermonuclear shell flashes on neutron stars are detected as bright X-ray bursts. Traditionally, their decay is modeled with an exponential function. However, this is not what theory predicts. The expected functional form for luminosities below the Eddington limit, at times when there is no significant nuclear burning, is a power law. We tested the exponential and power-law functional forms against the best data available: bursts measured with the high-throughput Proportional Counter Array (PCA) on board the Rossi X-ray Timing Explorer. We selected a sample of 35 'clean' and ordinary (i.e., shorter than a few minutes) bursts from 14 different neutron stars that 1) show a large dynamic range in luminosity, 2) are the least affected by disturbances by the accretion disk and 3) lack prolonged nuclear burning through the rp-process. We find indeed that for every burst a power law is a better description than an exponential function. We also find that the decay index is steep, 1.8 on average, and different for eve...

  8. The NACRE Thermonuclear Reaction Compilation and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Richard H. Cyburt; Brian D. Fields; Keith A. Olive

    2001-05-17T23:59:59.000Z

    The theoretical predictions of big bang nucleosynthesis (BBN) are dominated by uncertainties in the input nuclear reaction cross sections. In this paper, we examine the impact on BBN of the recent compilation of nuclear data and thermonuclear reactions rates by the NACRE collaboration. We confirm that the adopted rates do not make large overall changes in central values of predictions, but do affect the magnitude of the uncertainties in these predictions. Therefore, we then examine in detail the uncertainties in the individual reaction rates considered by NACRE. When the error estimates by NACRE are treated as 1\\sigma limits, the resulting BBN error budget is similar to those of previous tabulations. We propose two new procedures for deriving reaction rate uncertainties from the nuclear data: one which sets lower limits to the error, and one which we believe is a reasonable description of the present error budget. We propagate these uncertainty estimates through the BBN code, and find that when the nuclear data errors are described most accurately, the resulting light element uncertainties are notably smaller than in some previous tabulations, but larger than others. Using these results, we derive limits on the cosmic baryon-to-photon ratio $\\eta$, and compare this to independent limits on $\\eta$ from recent balloon-borne measurements of the cosmic microwave background radiation (CMB). We discuss means to improve the BBN results via key nuclear reaction measurements and light element observations.

  9. Thermonuclear X-ray Bursts: Theory vs. Observations

    E-Print Network [OSTI]

    Andrew Cumming

    2003-11-18T23:59:59.000Z

    I review our theoretical understanding of thermonuclear flashes on accreting neutron stars, concentrating on comparisons to observations. Sequences of regular Type I X-ray bursts from GS 1826-24 and 4U 1820-30 are very well described by the theory. I discuss recent work which attempts to use the observed burst properties in these sources to constrain the composition of the accreted material. For GS 1826-24, variations in the burst energetics with accretion rate indicate that the accreted material has solar metallicity; for 4U 1820-30, future observations should constrain the hydrogen fraction, testing evolutionary models. I briefly discuss the global bursting behavior of burst sources, which continues to be a major puzzle. Finally, I turn to superbursts, which naturally fit into the picture as unstable carbon ignition in a thick layer of heavy elements. I present new time-dependent models of the cooling tails of superbursts, and discuss the various interactions between superbursts and normal Type I bursts, and what can be learned from them.

  10. Laser-fusion targets for reactors

    DOE Patents [OSTI]

    Nuckolls, John H. (Livermore, CA); Thiessen, Albert R. (Livermore, CA)

    1987-01-01T23:59:59.000Z

    A laser target comprising a thermonuclear fuel capsule composed of a centrally located quantity of fuel surrounded by at least one or more layers or shells of material for forming an atmosphere around the capsule by a low energy laser prepulse. The fuel may be formed as a solid core or hollow shell, and, under certain applications, a pusher-layer or shell is located intermediate the fuel and the atmosphere forming material. The fuel is ignited by symmetrical implosion via energy produced by a laser, or other energy sources such as an electron beam machine or ion beam machine, whereby thermonuclear burn of the fuel capsule creates energy for applications such as generation of electricity via a laser fusion reactor.

  11. Experimental Investigation of the Root Cause Mechanism and Effectiveness of Mitigating Actions for Axial Offset Anomaly in Pressurized Water Reactors

    SciTech Connect (OSTI)

    Said Abdel-Khalik

    2005-07-02T23:59:59.000Z

    Axial offset anomaly (AOA) in pressurized water reactors refers to the presence of a significantly larger measured negative axial offset deviation than predicted by core design calculations. The neutron flux depression in the upper half of high-power rods experiencing significant subcooled boiling is believed to be caused by the concentration of boron species within the crud layer formed on the cladding surface. Recent investigations of the root-cause mechanism for AOA [1,2] suggest that boron build-up on the fuel is caused by precipitation of lithium metaborate (LiBO2) within the crud in regions of subcooled boiling. Indirect evidence in support of this hypothesis was inferred from operating experience at Callaway, where lithium return and hide-out were, respectively, observed following power reductions and power increases when AOA was present. However, direct evidence of lithium metaborate precipitation within the crud has, heretofore, not been shown because of its retrograde solubility. To this end, this investigation has been undertaken in order to directly verify or refute the proposed root-cause mechanism of AOA, and examine the effectiveness of possible mitigating actions to limit its impact in high power PWR cores.

  12. An experimental system for the n-butyl-lithium initiated polymerization of styrene in a multi-sampled batch reactor 

    E-Print Network [OSTI]

    Cox, James Harvey

    1974-01-01T23:59:59.000Z

    -hydrogen interconversions in- stead of the desired cleavage reaction. The sulfur-sulfur bond is a chromophore that absorbs ultraviolet light in the 255 nm region with a relatively low molar absorption (z = 400). This is suffi- max ciently large for the detection...- cally there are two broad divisions of experimental methods; the ultra-high purity, evacuated glass systems and the lower purity, more rugged, bench-scale systems. One analytical method, the spectrophotometric method, as used by Worsfold and Bywater...

  13. REVIEW OF EXPERIMENTAL CAPABILITIES AND HYDRODYNAMIC DATA FOR VALIDATION OF CFD-BASED PREDICTIONS FOR SLURRY BUBBLE COLUMN REACTORS

    SciTech Connect (OSTI)

    Donna Post Guillen; Daniel S. Wendt; Steven P. Antal; Michael Z. Podowski

    2007-11-01T23:59:59.000Z

    The purpose of this paper is to document the review of several open-literature sources of both experimental capabilities and published hydrodynamic data to aid in the validation of a Computational Fluid Dynamics (CFD) based model of a slurry bubble column (SBC). The review included searching the Web of Science, ISI Proceedings, and Inspec databases, internet searches as well as other open literature sources. The goal of this study was to identify available experimental facilities and relevant data. Integral (i.e., pertaining to the SBC system), as well as fundamental (i.e., separate effects are considered), data are included in the scope of this effort. The fundamental data is needed to validate the individual mechanistic models or closure laws used in a Computational Multiphase Fluid Dynamics (CMFD) simulation of a SBC. The fundamental data is generally focused on simple geometries (i.e., flow between parallel plates or cylindrical pipes) or custom-designed tests to focus on selected interfacial phenomena. Integral data covers the operation of a SBC as a system with coupled effects. This work highlights selected experimental capabilities and data for the purpose of SBC model validation, and is not meant to be an exhaustive summary.

  14. REVIEW OF EXPERIMENTAL CAPABILITIES AND HYDRODYNAMIC DATA FOR VALIDATION OF CFD BASED PREDICTIONS FOR SLURRY BUBBLE COLUMN REACTORS

    SciTech Connect (OSTI)

    Donna Post Guillen; Daniel S. Wendt

    2007-11-01T23:59:59.000Z

    The purpose of this paper is to document the review of several open-literature sources of both experimental capabilities and published hydrodynamic data to aid in the validation of a Computational Fluid Dynamics (CFD) based model of a slurry bubble column (SBC). The review included searching the Web of Science, ISI Proceedings, and Inspec databases, internet searches as well as other open literature sources. The goal of this study was to identify available experimental facilities and relevant data. Integral (i.e., pertaining to the SBC system), as well as fundamental (i.e., separate effects are considered), data are included in the scope of this effort. The fundamental data is needed to validate the individual mechanistic models or closure laws used in a Computational Multiphase Fluid Dynamics (CMFD) simulation of a SBC. The fundamental data is generally focused on simple geometries (i.e., flow between parallel plates or cylindrical pipes) or custom-designed tests to focus on selected interfacial phenomena. Integral data covers the operation of a SBC as a system with coupled effects. This work highlights selected experimental capabilities and data for the purpose of SBC model validation, and is not meant to be an exhaustive summary.

  15. The Sensitivity of Nucleosynthesis in Type I X-ray Bursts to Thermonuclear Reaction-Rate Variations

    E-Print Network [OSTI]

    Anuj Parikh; Jordi Jose; Fermin Moreno; Christian Iliadis

    2008-06-18T23:59:59.000Z

    We examine the sensitivity of nucleosynthesis in Type I X-ray bursts to variations in nuclear rates. As a large number of nuclear processes are involved in these phenomena -with the vast majority of reaction rates only determined theoretically due to the lack of any experimental information- our results can provide a means for determining which rates play significant roles in the thermonuclear runaway. These results may then motivate new experiments. For our studies, we have performed a comprehensive series of one-zone post-processing calculations in conjunction with various representative X-ray burst thermodynamic histories. We present those reactions whose rate variations have the largest effects on yields in our studies.

  16. Astrophysical S-factors of proton radiative capture for thermonuclear reactions

    E-Print Network [OSTI]

    S. B. Dubovichenko; A. V. Dzhazairov-Kakhramanov

    2011-12-09T23:59:59.000Z

    In this review we have considered the possibility to describe the astrophysical S-factors of radiative capture reactions with light atomic nuclei on the basis of the potential two-cluster model by taking into account the splitting the orbital states according to Young's schemes. Within this model, interaction of the nucleon clusters is described by local two-particle potential determined by fit to the scattering data and properties of bound states of these clusters. Many-body character of the problem is taken into account under some approximation, in terms of the allowed or forbidden by the Pauli principle states in intercluster potentials. An important feature of the approach is accounting for a dependence of interaction potential between clusters on the orbital Young scheme, which determines the permutation symmetry of the nucleon system. The astrophysical S-factors of the radiative capture processes in the p2H, p7Li and p12C systems are analyzed on the basis of this approach. It is shown that the approach allows one to describe quite reasonably experimental data available at low energies, when the phase shifts of cluster-cluster scattering are extracted from the data with minimal errors. In this connection the problem of experimental error decrease is exclusively urgent for the differential cross-sections of elastic scattering of light atomic nuclei at astrophysical energies and to perform a more accurate phase shift analysis. The increase in the accuracy will allow, in future, making more definite conclusions regarding the mechanisms and conditions of thermonuclear reactions, as well as understanding better their nature in general.

  17. Heat Transfer Simulation of Reactor Cavity Cooling System Experimental Facility using RELAP5-3D and Generation of View Factors using MCNP 

    E-Print Network [OSTI]

    Wu, Huali

    2013-08-08T23:59:59.000Z

    As one of the most attractive reactor types, The High Temperature Gas-cooled Reactor (HTGR) is designed to be passively safe with the incorporation of Reactor Cavity Cooling System (RCCS). In this paper, a RELAP5-3D simulation model is set up based...

  18. If cheaper fusion reactors were developed, such as from compact toroids

    E-Print Network [OSTI]

    Deinert, Mark

    FF (1984) Introduction to plasma physics and controlled thermonuclear fusion. Plenum, New York If cheaper fusion reactors were developed, such as from compact toroids If fusion­fission hybrids. Freidberg J (2006) Plasma physics and fusion energy. Cambridge University Press, Cambridge 3. "All

  19. Thermonuclear Stability of Material Accreting onto a Neutron Star

    E-Print Network [OSTI]

    Ramesh Narayan; Jeremy S. Heyl

    2003-08-22T23:59:59.000Z

    We present a global linear stability analysis of nuclear fuel accumulating on the surface of an accreting neutron star and we identify the conditions under which thermonuclear bursts are triggered. The analysis reproduces all the recognized regimes of hydrogen and helium bursts, and in addition shows that at high accretion rates, near the limit of stable burning, there is a regime of ``delayed mixed bursts'' which is distinct from the more usual ``prompt mixed bursts.'' In delayed mixed bursts, a large fraction of the fuel is burned stably before the burst is triggered. Bursts thus have longer recurrence times, but at the same time have somewhat smaller fluences. Therefore, the parameter alpha, which measures the ratio of the energy released via accretion to that generated through nuclear reactions in the burst, is up to an order of magnitude larger than for prompt bursts. This increase in alpha near the threshold of stable burning has been seen in observations. We explore a wide range of mass accretion rates, neutron star radii and core temperatures, and calculate a variety of burst properties. From a preliminary comparison with data, we suggest that bursting neutron stars may have hot cores, with T_{core} >~ 10^{7.5} K, consistent with interior cooling via the modified URCA or similar low-efficiency process, rather than T_{core} ~ 10^7 K, as expected for the direct URCA process. There is also an indication that neutron star radii are somewhat small <~ 10 km. Both of these conclusions need to be confirmed by comparing more careful calculations with better data.

  20. Kinetic simulation of thermonuclear-neutron production by a 10{sup 7}-A deuterium Z pinch

    SciTech Connect (OSTI)

    Welch, D. R.; Rose, D. V.; Thoma, C.; Clark, R. E.; Mostrom, C. B. [Voss Scientific, LLC, Albuquerque, New Mexico 87108 (United States); Stygar, W. A.; Leeper, R. J. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1196 (United States)

    2010-07-15T23:59:59.000Z

    Fully kinetic simulations have demonstrated that at sufficiently high currents, half of the neutrons produced by a deuterium Z-pinch are thermonuclear in origin. At 150-kA pinch current, O. A. Anderson et al. [Phys. Rev. 110, 1375 (1958)] clearly shows that essentially all of the neutrons produced by a deuterium pinch are not thermonuclear, but are initiated by an instability that creates beam-target neutrons. Since this paper, many subsequent authors have supported this result while others have claimed that pinch neutrons are, on the contrary, thermonuclear. To resolve this issue, fully kinetic, collisional, and electromagnetic simulations of the complete time evolution of a deuterium pinch have been performed. The simulations were performed with the implicit particle-in-cell code LSP, as described in D. R. Welch et al. [Phys. Rev. Lett. 103, 255002 (2009)]. At 10{sup 6} -A pinch currents, most of the neutrons are, indeed, beam-target in origin. At 15-MA current, half of the neutrons are thermonuclear and half are beam-target driven by instabilities that produce a power law fall off in the ion energy distribution function at large energy. Simulation results suggest that from 7- to 15-MA current, the fraction of thermonuclear neutrons is not sensitive to current and that the strong dependence of neutron yield on current will continue at currents greater than 15 MA.

  1. Contents of ITER deal revealed The Yomiuri Shimbun (May 27, 2005, 4 am)

    E-Print Network [OSTI]

    in thermonuclear fusion. The country also will supply 20 percent of workers to ITER facilities. The four other on the roles of host and non-hosting countries involved in the International Thermonuclear Experimental Reactor. The planned ITER is an experimental facility for a thermonuclear reactor designed to produce power by fusing

  2. Brussels, May 31, 2005 NOTES Basic 1

    E-Print Network [OSTI]

    and the exploitation of an experimental thermonuclear reactor (ITER) and implementation of the calendar envisaged and the exploitation of an experimental thermonuclear reactor (ITER) and implementation of the calendar envisaged thermonuclear engine. Six parts take part in the negotiations: China, South Korea, the United States, Japan

  3. Also on the agenda would be

    E-Print Network [OSTI]

    the multi- billion dollar International Thermonuclear Experimental Reactor (ITER), one of the most exciting the multi-billion dollar International Thermonuclear Experimental Reactor (ITER), one of the most exciting International Thermonuclear French President Jacques Chirac Six Month World Exposition Beijing Tiananmen Square

  4. On the Stability of Thermonuclear Burning Fronts in Type Ia Supernovae

    E-Print Network [OSTI]

    F. K. Roepke; W. Hillebrandt

    2004-04-26T23:59:59.000Z

    The propagation of cellularly stabilized thermonuclear flames is investigated by means of numerical simulations. In Type Ia supernova explosions the corresponding burning regime establishes at scales below the Gibson length. The cellular flame stabilization - which is a result of an interplay between the Landau-Darrieus instability and a nonlinear stabilization mechanism - is studied for the case of propagation into quiescent fuel as well as interaction with vortical fuel flows. Our simulations indicate that in thermonuclear supernova explosions stable cellular flames develop around the Gibson scale and that deflagration-to-detonation transition is unlikely to be triggered from flame evolution effects here.

  5. Contrib. Plasma Phys. 53, No. 45, 397 405 (2013) / DOI 10.1002/ctpp.201200094 Electron screening effect on stellar thermonuclear fusion

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    effect on stellar thermonuclear fusion Alexander Y. Potekhin1,2 and Gilles Chabrier2,3 1 Ioffe Physical. In addition, we examine some recent unconventional theo- retical results on stellar thermonuclear fusionsA, Weinheim 1 Introduction Thermonuclear reactions play a crucial role in stellar evolution. Nuclear fusion

  6. Mon. Not. R. Astron. Soc. 401, 26 (2010) doi:10.1111/j.1365-2966.2009.15632.x Systematic variation in the apparent burning area of thermonuclear

    E-Print Network [OSTI]

    Miller, Cole

    2010-01-01T23:59:59.000Z

    in the apparent burning area of thermonuclear bursts and its implication for neutron star radius measurement Sudip area during the decay portions of thermonuclear (type I) X-ray bursts. However, this apparent area are challenging. Thermonuclear bursts provide one of the very few promising methods to measure the neutron star

  7. PHYS 390 Lecture 20 -Reactions III -Thermonuclear processes 20 -1 2001 by David Boal, Simon Fraser University. All rights reserved; further resale or copying is strictly prohibited.

    E-Print Network [OSTI]

    Boal, David

    PHYS 390 Lecture 20 - Reactions III - Thermonuclear processes 20 - 1 © 2001 by David Boal, Simon - Reactions III - Thermonuclear processes What's Important: · energy-dependent cross sections · complete rate 20 - Reactions III - Thermonuclear processes 20 - 2 © 2001 by David Boal, Simon Fraser University

  8. Course: FUSION SCIENCE AND ENGINEERING Universit degli Studi di Padova

    E-Print Network [OSTI]

    Cesare, Bernardo

    the subject of controlled thermonuclear fusion in magnetically confined plasmas. Both fusion science of Controlled Thermonuclear Fusion, b) Engineering of a Magnetically Confined Fusion Reactor, c) ExperimentalCourse: FUSION SCIENCE AND ENGINEERING Università degli Studi di Padova in agreement

  9. Complex workplace radiation fields at European high-energy accelerators and thermonuclear fusion facilities

    E-Print Network [OSTI]

    Bilski, P; D'Errico, F; Esposito, A; Fehrenbacher, G; Fernàndez, F; Fuchs, A; Golnik, N; Lacoste, V; Leuschner, A; Sandri, S; Silari, M; Spurny, F; Wiegel, B; Wright, P

    2006-01-01T23:59:59.000Z

    This report outlines the research needs and research activities within Europe to develop new and improved methods and techniques for the characterization of complex radiation fields at workplaces around high-energy accelerators and the next generation of thermonuclear fusion facilities under the auspices of the COordinated Network for RAdiation Dosimetry (CONRAD) project funded by the European Commission.

  10. Millihertz quasi-periodic oscillations and thermonuclear bursts from Terzan 5: A showcase of burning regimes

    E-Print Network [OSTI]

    Linares, M.

    We present a comprehensive study of the thermonuclear bursts and millihertz quasi-periodic oscillations (mHz QPOs) from the neutron star (NS) transient and 11 Hz X-ray pulsar IGR J17480–2446, located in the globular cluster ...

  11. Reactor Safety Research Programs

    SciTech Connect (OSTI)

    Edler, S. K.

    1981-07-01T23:59:59.000Z

    This document summarizes the work performed by Pacific Northwest Laboratory (PNL) from January 1 through March 31, 1981, for the Division of Reactor Safety Research within the U.S. Nuclear Regulatory Commission (NRC). Evaluations of nondestructive examination (NDE) techniques and instrumentation are reported; areas of investigation include demonstrating the feasibility of determining the strength of structural graphite, evaluating the feasibility of detecting and analyzing flaw growth in reactor pressure boundary systems, examining NDE reliability and probabilistic fracture mechanics, and assessing the integrity of pressurized water reactor (PWR) steam generator tubes where service-induced degradation has been indicated. Experimental data and analytical models are being provided to aid in decision-making regarding pipeto- pipe impacts following postulated breaks in high-energy fluid system piping. Core thermal models are being developed to provide better digital codes to compute the behavior of full-scale reactor systems under postulated accident conditions. Fuel assemblies and analytical support are being provided for experimental programs at other facilities. These programs include loss-ofcoolant accident (LOCA) simulation tests at the NRU reactor, Chalk River, Canada; fuel rod deformation, severe fuel damage, and postaccident coolability tests for the ESSOR reactor Super Sara Test Program, Ispra, Italy; the instrumented fuel assembly irradiation program at Halden, Norway; and experimental programs at the Power Burst Facility, Idaho National Engineering Laboratory (INEL). These programs will provide data for computer modeling of reactor system and fuel performance during various abnormal operating conditions.

  12. CONDENSATION IN EJECTA FROM DENSE THERMONUCLEAR SUPERNOVAE. T. Yu1, B. S. Meyer1, A. V. Fedkin2, and L. Grossman2,3, 1Department of Physics and Astronomy, Clemson University, Clemson, SC

    E-Print Network [OSTI]

    Grossman, Lawrence

    CONDENSATION IN EJECTA FROM DENSE THERMONUCLEAR SUPERNOVAE. T. Yu1, B. S. Meyer1, A. V. Fedkin2 Thermonuclear Supernova Model: Thermonuclear (Type Ia) supernovae are explosions of white dwarf stars. Our model and then oxy- gen burning proceed under degenerate conditions, a thermonuclear runaway occurs, which leads

  13. Charged-Particle Thermonuclear Reaction Rates: III. Nuclear Physics Input

    E-Print Network [OSTI]

    Christian Iliadis; Richard Longland; Art Champagne; Alain Coc

    2010-04-23T23:59:59.000Z

    The nuclear physics input used to compute the Monte Carlo reaction rates and probability density functions that are tabulated in the second paper of this series (Paper II) is presented. Specifically, we publish the input files to the Monte Carlo reaction rate code RatesMC, which is based on the formalism presented in the first paper of this series (Paper I). This data base contains overwhelmingly experimental nuclear physics information. The survey of literature for this review was concluded in November 2009.

  14. THE FERMI-GBM X-RAY BURST MONITOR: THERMONUCLEAR BURSTS FROM 4U 0614+09

    E-Print Network [OSTI]

    Connaughton, V.

    Thermonuclear bursts from slowly accreting neutron stars (NSs) have proven difficult to detect, yet they are potential probes of the thermal properties of the NS interior. During the first year of a systematic all-sky ...

  15. Thermonuclear fusion in dense stars: Electron screening, conductive cooling, and magnetic field effects

    E-Print Network [OSTI]

    Potekhin, A Y

    2012-01-01T23:59:59.000Z

    We study the plasma correlation effects on nonresonant thermonuclear reactions of carbon and oxygen in the interiors of white dwarfs and liquid envelopes of neutron stars. We examine the effects of electron screening on thermodynamic enhancement of thermonuclear reactions in dense plasmas beyond the linear mixing rule. Using these improved enhancement factors, we calculate carbon and oxygen ignition curves in white dwarfs and neutron stars. The energy balance and ignition conditions in neutron star envelopes are evaluated, taking their detailed thermal structure into account. The result is compared to the simplified "one-zone model," which is routinely used in the literature. We also consider the effect of strong magnetic fields on the ignition curves in the ocean of magnetars.

  16. Level set simulations of turbulent thermonuclear deflagration in degenerate carbon and oxygen

    E-Print Network [OSTI]

    Schmidt, W; Niemeyer, J C

    2005-01-01T23:59:59.000Z

    We study the dynamics of thermonuclear flames propagating in fuel stirred by stochastic forcing. The fuel consists of carbon and oxygen in a state which is encountered in white dwarfs close to the Chandrasekhar limit. The level set method is applied to represent the flame fronts numerically. The computational domain for the numerical simulations is cubic, and periodic boundary conditions are imposed. The goal is the development of a suitable flame speed model for the small-scale dynamics of turbulent deflagration in thermonuclear supernovae. Because the burning process in a supernova explosion is transient and spatially inhomogeneous, the localised determination of subgrid scale closure parameters is essential. We formulate a semi-localised model based on the dynamical equation for the subgrid scale turbulence energy $k_{\\mathrm{sgs}}$. The turbulent flame speed $s_{\\mathrm{t}}$ is of the order $\\sqrt{2k_{\\mathrm{sgs}}}$. In particular, the subgrid scale model features a dynamic procedure for the calculation ...

  17. Compression and combustion of non-cryogenic targets with a solid thermonuclear fuel for inertial fusion

    SciTech Connect (OSTI)

    Gus'kov, S. Yu., E-mail: guskov@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Zmitrenko, N. V. [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation); Sherman, V. E. [St. Petersburg State Polytechnic University (Russian Federation)

    2013-04-15T23:59:59.000Z

    Variants of a target with a solid thermonuclear fuel in the form of deuterium-tritium hydrides of light metals for an inertial fusion have been proposed. The laser-pulse-induced compression of non-cryogenic targets, as well as ignition and combustion of such targets, has been examined. The numerical calculations show that, despite a decrease in the caloric content of the fuel and an increase in the energy losses on intrinsic radiation in the target containing deuterium-tritium hydrides of light metals as compared to the target containing deuterium-tritium ice, the non-cryogenic target can ensure the fusion gain sufficient for its use in the energy cycle of a thermonuclear power plant based on the inertial plasma confinement method.

  18. Oscillations During Thermonuclear X-ray Bursts: A New Probe of Neutron Stars

    E-Print Network [OSTI]

    Tod E. Strohmayer

    1999-11-19T23:59:59.000Z

    Observations of thermonuclear (Type I) X-ray bursts from neutron stars in low mass X-ray binaries (LMXB) with the Rossi X-ray Timing Explorer (RXTE) have revealed large amplitude, high coherence X-ray brightness oscillations with frequencies in the 300 - 600 Hz range. Substantial spectral and timing evidence point to rotational modulation of the X-ray burst flux as the cause of these oscillations, and it is likely that they reveal the spin frequencies of neutron stars in LMXB from which they are detected. Here I review the status of our knowledge of these oscillations and describe how they can be used to constrain the masses and radii of neutron stars as well as the physics of thermonuclear burning on accreting neutron stars.

  19. The variation of the fine structure constant: testing the dipole model with thermonuclear supernovae

    E-Print Network [OSTI]

    Kraiselburd, Lucila; Negrelli, Carolina; Berro, Enrique García

    2014-01-01T23:59:59.000Z

    The large-number hypothesis conjectures that fundamental constants may vary. Accordingly, the spacetime variation of fundamental constants has been an active subject of research for decades. Recently, using data obtained with large telescopes a phenomenological model in which the fine structure constant might vary spatially has been proposed. We test whether this hypothetical spatial variation of {\\alpha}, which follows a dipole law, is compatible with the data of distant thermonuclear supernovae. Unlike previous works, in our calculations we consider not only the variation of the luminosity distance when a varying {\\alpha} is adopted, but we also take into account the variation of the peak luminosity of Type Ia supernovae resulting from a variation of {\\alpha}. This is done using an empirical relation for the peak bolometric magnitude of thermonuclear supernovae that correctly reproduces the results of detailed numerical simulations. We find that there is no significant difference between the several phenome...

  20. A revised thermonuclear rate of $^{7}$Be($n$,$\\alpha$)$^{4}$He relevant to Big-Bang nucleosynthesis

    E-Print Network [OSTI]

    Hou, S Q; Kubono, S; Chen, Y S

    2015-01-01T23:59:59.000Z

    In the standard Big-Bang nucleosynthesis (BBN) model, the primordial $^7$Li abundance is overestimated by about a factor of 2--3 comparing to the astronomical observations, so called the pending cosmological lithium problem. The $^7$Be($n$,$\\alpha$)$^4$He reaction, which may affect the $^7$Li abundance, was regarded as the secondary important reaction in destructing the $^7$Be nucleus in BBN. However, the thermonuclear rate of $^7$Be($n$,$\\alpha$)$^4$He has not been well studied so far. This reaction rate was firstly estimated by Wagoner in 1969, which has been generally adopted in the current BBN simulations and the reaction rate library. This simple estimation involved only a direct-capture reaction mechanism, but the resonant contribution should be also considered according to the later experimental results. In this work, we have revised this rate based on the indirect cross-section data available for the $^4$He($\\alpha$,$n$)$^7$Be and $^4$He($\\alpha$,$p$)$^7$Li reactions, with the charge symmetry and deta...

  1. Hydrodynamic simulations of a combined hydrogen, helium thermonuclear runaway on a 10-km neutron star

    SciTech Connect (OSTI)

    Starrfield, S.; Kenyon, S.; Truran, J.W.; Sparks, W.M.

    1983-01-01T23:59:59.000Z

    We have used a Lagrangian, hydrodynamic stellar-evolution computer code to evolve a thermonuclear runaway in the accreted hydrogen rich envelope of a 1.0M, 10-km neutron star. Our simulation produced an outburst which lasted about 2000 sec and peak effective temperature was 3 keV. The peak luminosity exceeded 2 x 10/sup 5/ L. A shock wave caused a precursor in the light curve which lasted 10/sup -5/ sec.

  2. Application of a new screening model to thermonuclear reactions of the rp process

    E-Print Network [OSTI]

    Theodore Liolios

    2003-05-09T23:59:59.000Z

    A new screening model for astrophysical thermonuclear reactions was derived recently which improved Salpeter's weak-screening one. In the present work we prove that the new model can also give very reliable screening enhancement factors (SEFs) when applied to the rp process. According to the results of the new model, which agree well with Mitler's SEFs, the screened rp reaction rates can be, at most, twice as fast as the unscreened ones.

  3. MILLIHERTZ QUASI-PERIODIC OSCILLATIONS AND THERMONUCLEAR BURSTS FROM TERZAN 5: A SHOWCASE OF BURNING REGIMES

    SciTech Connect (OSTI)

    Linares, M.; Chakrabarty, D. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Altamirano, D. [Astronomical Institute 'Anton Pannekoek', University of Amsterdam and Center for High-Energy Astrophysics, P.O. BOX 94249, 1090 GE Amsterdam (Netherlands); Cumming, A. [Department of Physics, McGill University, 3600 Rue University, Montreal, QC H3A 2T8 (Canada); Keek, L. [School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)

    2012-04-01T23:59:59.000Z

    We present a comprehensive study of the thermonuclear bursts and millihertz quasi-periodic oscillations (mHz QPOs) from the neutron star (NS) transient and 11 Hz X-ray pulsar IGR J17480-2446, located in the globular cluster Terzan 5. The increase in burst rate that we found during its 2010 outburst, when persistent luminosity rose from 0.1 to 0.5 times the Eddington limit, is in qualitative agreement with thermonuclear burning theory yet contrary to all previous observations of thermonuclear bursts. Thermonuclear bursts gradually evolved into a mHz QPO when the accretion rate increased, and vice versa. The mHz QPOs from IGR J17480-2446 resemble those previously observed in other accreting NSs, yet they feature lower frequencies (by a factor {approx}3) and occur when the persistent luminosity is higher (by a factor 4-25). We find four distinct bursting regimes and a steep (close to inverse cubic) decrease of the burst recurrence time with increasing persistent luminosity. We compare these findings to nuclear burning models and find evidence for a transition between the pure helium and mixed hydrogen/helium ignition regimes when the persistent luminosity was about 0.3 times the Eddington limit. We also point out important discrepancies between the observed bursts and theory, which predicts brighter and less frequent bursts, and suggest that an additional source of heat in the NS envelope is required to reconcile the observed and expected burst properties. We discuss the impact of NS magnetic field and spin on the expected nuclear burning regimes, in the context of this particular pulsar.

  4. Lightcurves of thermonuclear supernovae as a probe of the explosion mechanism and their use in cosmology

    E-Print Network [OSTI]

    S. Blinnikov; E. Sorokina

    2002-12-30T23:59:59.000Z

    Thermonuclear supernovae are valuable for cosmology but their physics is not yet fully understood. Modeling the development and propagation of nuclear flame is complicated by numerous instabilities. The predictions of supernova light curves still involve some simplifying assumptions, but one can use the comparison of the computed fluxes with observations to constrain the explosion mechanism. In spite of great progress in recent years, a number of issues remains unsolved both in flame physics and light curve modeling.

  5. Thermonuclear Runaways on Accreting White Dwarfs: Models of Classical Novae Explosions

    E-Print Network [OSTI]

    Margarita Hernanz; Jordi Jose

    2000-01-11T23:59:59.000Z

    The mechanism of classical novae explosions is explained, together with some of their observational properties. The scarce but not null impact of novae in the chemical evolution of the Milky Way is analyzed, as well as their relevance for the radioactivity in the Galaxy. A special emphasis is given to the predicted gamma-ray emission from novae and its relationship with the thermonuclear model itself and its related nucleosynthesis.

  6. Thermonuclear explosion of rotating massive stars could explain core-collapse supernovae

    E-Print Network [OSTI]

    Kushnir, Doron

    2015-01-01T23:59:59.000Z

    It is widely thought that core-collapse supernovae (CCSNe), the explosions of massive stars following the collapse of the stars' iron cores, is obtained due to energy deposition by neutrinos. So far, this scenario was not demonstrated from first principles. Kushnir and Katz (2014) have recently shown, by using one-dimensional simulations, that if the neutrinos failed to explode the star, a thermonuclear explosion of the outer shells is possible for some (tuned) initial profiles. However, the energy released was small and negligible amounts of ejected $^{56}$Ni were obtained, implying that these one-dimensional collapse induced thermonuclear explosions (CITE) are unlikely to represent typical CCSNe. Here I provide evidence supporting a scenario in which the majority of CCSNe are the result of CITE. I use two-dimensional simulations to show that collapse of stars that include slowly (few percent of breakup) rotating $\\sim0.1-10\\,M_{\\odot}$ shells of mixed helium-oxygen, leads to an ignition of a thermonuclear d...

  7. --No Title--

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    from national laboratories and universities. Leading the list was the International Thermonuclear Experimental Reactor, a facility capable of producing a "burning plasma"...

  8. Y-12s Building 9212 and the Uranium Processing Facility, part...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    is the ultimate answer to the world's ever increasing need for energy. Achieving the fusion of deuterium and tritium in the International Thermonuclear Experimental Reactor is...

  9. E-Print Network 3.0 - armoured actively cooled Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    on the actively cooled plasma facing components (PFCs) of the International Thermonuclear Experimental Reactor... of the actively cooled component itself. These have...

  10. U.S. and China Announce Cooperation on FutureGen and Sign Energy...

    Broader source: Energy.gov (indexed) [DOE]

    a Hydrogen Economy; the Carbon Sequestration Leadership Forum; the International Thermonuclear Experimental Reactor; and the Generation IV International Forum. Secretary Bodman...

  11. PPPL-3171 -Preprint Date: May 1996, UC-421, 423, 427 Simulations of alpha particle ripple loss from the

    E-Print Network [OSTI]

    Thermonuclear Experimental Reactor (ITER) [Plasma Physics and Controlled Nuclear Fusion Research (International from the International Thermonuclear Experimental Reactor M. H. Redi, R. V. Budny, D. C. McCune, C. O for D shaped ripple contours. In contrast to alpha loss simulations for the Tokamak Fusion Test Reactor

  12. Reactor Safety Research Programs

    SciTech Connect (OSTI)

    Dotson, CW

    1980-08-01T23:59:59.000Z

    This document summarizes the work performed by Pacific Northwest laboratory from October 1 through December 31, 1979, for the Division of Reactor Safety Research within the Nuclear Regulatory Commission. Evaluation of nondestructive examination (NDE) techniques and instrumentation are reported; areas of investigation include demonstrating the feasibilty of determining structural graphite strength, evaluating the feasibilty of detecting and analyzing flaw growth in reactor pressure boundary systems, examining NDE reliability and probabilistic fracture mechanics, and assessing the remaining integrity of pressurized water reactor steam generator tubes where service-induced degradation has been indicated. Test assemblies and analytical support are being provided for experimental programs at other facilities. These programs include the loss-of-coolant accident simulation tests at the NRU reactor, Chalk River, Canada; the fuel rod deformation and post-accident coolability tests for the ESSOR Test Reactor Program, lspra, Italy; the blowdown and reflood tests in the test facility at Cadarache, France; the instrumented fuel assembly irradiation program at Halden, Norway; and the experimental programs at the Power Burst Facility, Idaho National Engineering Laboratory. These programs will provide data for computer modeling of reactor system and fuel performance during various abnormal operating conditions.

  13. RECENT PROGRESS IN HEAVY ION SOURCES

    E-Print Network [OSTI]

    Clark, D.J.

    2010-01-01T23:59:59.000Z

    beams of hydrogen into thermonuclear fusion reactors. Ain magnetic confinement thermonuclear devices, such as

  14. NUCLEAR MATERIALS RESEARCH PROGRESS REPORTS FROM 1977

    E-Print Network [OSTI]

    Olander, D.R.

    2012-01-01T23:59:59.000Z

    Chemical Effects of Thermonuclear Plasma Interactions Withfor Controlled Thermonuclear Reactor (CTR), USAEC Report LA-

  15. Reactor physics project final report

    E-Print Network [OSTI]

    Driscoll, Michael J.

    1970-01-01T23:59:59.000Z

    This is the final report in an experimental and theoretical program to develop and apply single- and few-element methods for the determination of reactor lattice parameters. The period covered by the report is January 1, ...

  16. Interfacial effects in fast reactors

    E-Print Network [OSTI]

    Saidi, Mohammad Said

    1979-01-01T23:59:59.000Z

    The problem of increased resonance capture rates near zone interfaces in fast reactor media has been examined both theoretically and experimentally. An interface traversing assembly was designed, constructed and employed ...

  17. Heat Transfer Simulation of Reactor Cavity Cooling System Experimental Facility using RELAP5-3D and Generation of View Factors using MCNP

    E-Print Network [OSTI]

    Wu, Huali

    2013-08-08T23:59:59.000Z

    with nine pipes in the cavity, return and supply manifolds connecting standing pipes with water tank and a cylindrical water tank situated at top of the cavity (as shown in Figure 5). In the facility, the cylindrical reactor vessel is approximately... Simulation ......................................................................... 14 2.3.1 Water Tank as Single Volume Without Secondary Loop ............................. 14 2.3.2 Water Tank as Pipe with Secondary Loop...

  18. Evidence for a New Path to the Self-Sustainment of the Thermonuclear Fusion Reactions in Magnetically Confined Burning Plasma Experiments

    E-Print Network [OSTI]

    Evidence for a New Path to the Self-Sustainment of the Thermonuclear Fusion Reactions in Magnetically Confined Burning Plasma Experiments

  19. A Characterization of the Brightness Oscillations During Thermonuclear Bursts From 4U 1636-536

    E-Print Network [OSTI]

    M. Coleman Miller

    1999-04-08T23:59:59.000Z

    The discovery of nearly coherent brightness oscillations during thermonuclear X-ray bursts from six neutron-star low-mass X-ray binaries has opened up a new way to study the propagation of thermonuclear burning, and may ultimately lead to greater understanding of thermonuclear propagation in other astrophysical contexts, such as in Type Ia supernovae. Here we report detailed analyses of the ~580 Hz brightness oscillations during bursts from 4U 1636-536. We investigate the bursts as a whole and, in more detail, the initial portions of the bursts. We analyze the ~580 Hz oscillations in the initial 0.75 seconds of the five bursts that were used in a previous search for a brightness oscillation at the expected ~290 Hz spin frequency, and find that if the same frequency model describes all five bursts there is insufficient data to require more than a constant frequency or, possibly, a frequency plus a frequency derivative. Therefore, although it is appropriate to use an arbitrarily complicated model of the ~580 Hz oscillations to generate a candidate waveform for the ~290 Hz oscillations, models with more than two parameters are not required by the data. For the bursts as a whole we show that the characteristics of the brightness oscillations vary greatly from burst to burst. We find, however, that in at least one of the bursts, and possibly in three of the four that have strong brightness oscillations throughout the burst, the oscillation frequency reaches a maximum several seconds into the burst and then decreases. This behavior has not been reported previously for burst brightness oscillations, and it poses a challenge to the standard burning layer expansion explanation for the frequency changes.

  20. On the Thermonuclear Runaway in Type Ia Supernovae: How to run away?

    E-Print Network [OSTI]

    P. Hoeflich; J. Stein

    2001-12-07T23:59:59.000Z

    Type Ia Supernovae are thought to be thermonuclear explosions of massive white dwarfs (WD). We present the first study of multi-dimensional effects during the final hours prior to the thermonuclear runaway which leads to the explosion. The calculations utilize an implicit, 2-D hydro code.Mixing and the ignition process are studied in detail. We find that the initial chemical structure of the WD is changed but the material is not fully homogenized. The exploding WD sustains a central region with a low C/O ratio. This implies that the explosive nuclear burning will begin in a partially C-depleted environment. The thermonuclear runaway happens in a well defined region close to the center. It is induced by compressional heat when matter is brought inwards by convective flows. We find no evidence for multiple spot or strong off-center ignition. Convective velocities are of the order of 100 km/sec which is well above the effective burning speeds in SNe Ia previously expected right after the runaway. For about 0.5 to 1 sec, the speed of the burning front will neither be determined by the laminar speed nor the Rayleigh-Taylor instabilities but by convective flows produced prior to the runaway. The consequences are discussed for our under- standing of the detailed physics of the flame propagation, the deflagration detonation transition, and the nucleosynthesis in the central layers. Our results strongly suggest the pre-conditioning of the progenitor as a key-factor for our understanding of the diversity in SNeIa.

  1. Charged-Particle Thermonuclear Reaction Rates: IV. Comparison to Previous Work

    E-Print Network [OSTI]

    Christian Iliadis; Richard Longland; Art Champagne; Alain Coc

    2010-04-23T23:59:59.000Z

    We compare our Monte Carlo reaction rates (see Paper II of this series) to previous results that were obtained by using the classical method of computing thermonuclear reaction rates. For each reaction, the comparison is presented using two types of graphs: the first shows the change in reaction rate uncertainties, while the second displays our new results normalized to the previously recommended reaction rate. We find that the rates have changed significantly for almost all reactions considered here. The changes are caused by (i) our new Monte Carlo method of computing reaction rates (see Paper I of this series), and (ii) newly available nuclear physics information (see Paper III of this series).

  2. Enhancement of Resonant Thermonuclear Reaction Rates in Extremely Dense Stellar Plasmas

    E-Print Network [OSTI]

    Naoki Itoh; Nami Tomizawa; Shinya Wanajo; Satoshi Nozawa

    2002-12-06T23:59:59.000Z

    The enhancement factor of the resonant thermonuclear reaction rates is calculated for the extremely dense stellar plasmas in the liquid phase. In order to calculate the enhancement factor we use the screening potential which is deduced from the numerical experiment of the classical one-component plasma. It is found that the enhancement is tremendous for white dwarf densities if the ^{12}C + ^{12}C fusion cross sections show resonant behavior in the astrophysical energy range. We summarize our numerical results by accurate analytic fitting formulae.

  3. A revised thermonuclear rate of $^{7}$Be($n$,$?$)$^{4}$He relevant to Big-Bang nucleosynthesis

    E-Print Network [OSTI]

    S. Q. Hou; J. J. He; S. Kubono; Y. S. Chen

    2015-02-13T23:59:59.000Z

    In the standard Big-Bang nucleosynthesis (BBN) model, the primordial $^7$Li abundance is overestimated by about a factor of 2--3 comparing to the astronomical observations, so called the pending cosmological lithium problem. The $^7$Be($n$,$\\alpha$)$^4$He reaction, which may affect the $^7$Li abundance, was regarded as the secondary important reaction in destructing the $^7$Be nucleus in BBN. However, the thermonuclear rate of $^7$Be($n$,$\\alpha$)$^4$He has not been well studied so far. This reaction rate was firstly estimated by Wagoner in 1969, which has been generally adopted in the current BBN simulations and the reaction rate library. This simple estimation involved only a direct-capture reaction mechanism, but the resonant contribution should be also considered according to the later experimental results. In this work, we have revised this rate based on the indirect cross-section data available for the $^4$He($\\alpha$,$n$)$^7$Be and $^4$He($\\alpha$,$p$)$^7$Li reactions, with the charge symmetry and detailed-balance principle. Our new result shows that the previous rate (acting as an upper limit) is overestimated by about a factor of ten. The BBN simulation shows that the present rate leads to a 1.2\\% increase in the final $^7$Li abundance compared to the result using the Wagoner rate, and hence the present rate even worsens the $^7$Li problem. By the present estimation, the role of $^7$Be($n$,$\\alpha$)$^4$He in destroying $^7$Be is weakened from the secondary importance to the third, and the $^7$Be($d$,$p$)2$^4$He reaction becomes of secondary importance in destructing $^7$Be.

  4. Russian scientists to join round-the-world computer network ring. 28.01.2004, 21.08

    E-Print Network [OSTI]

    in order to exchange with their foreign colleagues information on thermonuclear fusion and the creation thermonuclear experimental reactor (ITER) project have an opportunity to offer technical solutions for building of ITER, Velikhov said the decision on the site for the world' s first international thermonuclear

  5. English home Forum Photo Gallery Features Newsletter Archive About US Help Site Map languages Culture/Life

    E-Print Network [OSTI]

    and tomorrow's electricity-producing fusion power plants. The new Chinese investment into the thermonuclear invests more into thermonuclear reaction study China's announced Friday in to invest 50 million yuan (6 million US dollars) more to the country's ongoing research on thermonuclear experimental reactors

  6. thermonuclear functions

    E-Print Network [OSTI]

    M. Aslam Chaudhry

    1999-01-01T23:59:59.000Z

    Two representations of the extended gamma functions ? 2,0 0,2 [(b,x)] are proved. These representations are exploited to find a transformation relation between two Fox’s H-functions. These results are used to solve Fox’s H-function in terms of Meijer’s G-function for certain values of the parameters. A closed form representation of the kernel of the Bessel type integral transform is also proved. 1.

  7. Thermonuclear Flame Spreading on Rapidly Spinning Neutron Stars: Indications of the Coriolis Force?

    E-Print Network [OSTI]

    Sudip Bhattacharyya; Tod E. Strohmayer

    2007-08-27T23:59:59.000Z

    Millisecond period brightness oscillations during the intensity rise of thermonuclear X-ray bursts are likely caused by an azimuthally asymmetric, expanding burning region on the stellar surface. The time evolution of the oscillation amplitude during the intensity rise encodes information on how the thermonuclear flames spread across the stellar surface. This process depends on properties of the accreted burning layer, surface fluid motions, and the surface magnetic field structure, and thus can provide insight into these stellar properties. We present two examples of bursts from different sources that show a decrease in oscillation amplitude during the intensity rise. Using theoretical modeling, we demonstrate that the observed amplitude evolution of these bursts is not well described by a uniformly expanding circular burning region. We further show that by including in our model the salient aspects of the Coriolis force (as described by Spitkovsky, Levin, and Ushomirsky) we can qualitatively reproduce the observed evolution curves. Our modeling shows that the evolutionary structure of burst oscillation amplitude is sensitive to the nature of flame spreading, while the actual amplitude values can be very useful to constrain some source parameters.

  8. Relics of metal-free low mass stars exploding as thermonuclear supernovae

    E-Print Network [OSTI]

    Takuji Tsujimoto; Toshikazu Shigeyama

    2006-01-16T23:59:59.000Z

    Renewed interest in the first stars that were formed in the universe has led to the discovery of extremely iron-poor stars. Since several competing scenarios exist, our understanding of the mass range that determines the observed elemental abundances remains unclear. In this study, we consider three well-studied metal-poor stars in terms of the theoretical supernovae (SNe) model. Our results suggest that the observed abundance patterns in the metal-poor star BD +80 245 and the pair of stars HD 134439/40 agree strongly with the theoretical possibility that these stars inherited their heavy element abundance patterns from SNe initiated by thermonuclear runaways in the degenerate carbon-oxygen cores of primordial asymptotic giant branch stars with \\~3.5-5 solar masses. Recent theoretical calculations have predicted that such SNe could be originated from metal-free stars in the intermediate mass range. On the other hand, intermediate mass stars containing some metals would end their lives as white dwarfs after expelling their envelopes in the wind due to intense momentum transport from outgoing photons to heavy elements. This new pathway for the formation of SNe requires that stars are formed from the primordial gas. Thus, we suggest that stars of a few solar masses were formed from the primordial gas and that some of them caused thermonuclear explosions when the mass of their degenerate carbon-oxygen cores increased to the Chandrasekhar limit without experiencing efficient mass loss.

  9. Magnetic burial and the harmonic content of millisecond oscillations in thermonuclear X-ray bursts

    E-Print Network [OSTI]

    D. J. B. Payne; A. Melatos

    2006-07-11T23:59:59.000Z

    Matter accreting onto the magnetic poles of a neutron star spreads under gravity towards the magnetic equator, burying the polar magnetic field and compressing it into a narrow equatorial belt. Steady-state, Grad-Shafranov calculations with a self-consistent mass-flux distribution (and a semi-quantitative treatment of Ohmic diffusion) show that, for $\\Ma \\gtrsim 10^{-5}\\Msun$, the maximum field strength and latitudinal half-width of the equatorial magnetic belt are $B_{\\rm max} = 5.6\\times 10^{15} (\\Ma/10^{-4}\\Msun)^{0.32}$ G and $\\Delta\\theta = \\max[3^{\\circ} (\\Ma/10^{-4}\\Msun)^{-1.5},3^{\\circ} (\\Ma/10^{-4}\\Msun)^{0.5}(\\dot{M}_{\\rm a}/10^{-8}\\Msun {\\rm yr}^{-1})^{-0.5}]$ respectively, where $\\Ma$ is the total accreted mass and $\\dot{M}_{\\rm a}$ is the accretion rate. It is shown that the belt prevents north-south heat transport by conduction, convection, radiation, and ageostrophic shear. This may explain why millisecond oscillations observed in the tails of thermonuclear (type I) X-ray bursts in low-mass X-ray binaries are highly sinusoidal: the thermonuclear flame is sequestered in the magnetic hemisphere which ignites first. The model is also consistent with the occasional occurrence of closely spaced pairs of bursts. Time-dependent, ideal-magnetohydrodynamic simulations confirm that the equatorial belt is not disrupted by Parker and interchange instabilities.

  10. Level set simulations of turbulent thermonuclear deflagration in degenerate carbon and oxygen

    E-Print Network [OSTI]

    W. Schmidt; W. Hillebrandt; J. C. Niemeyer

    2005-08-02T23:59:59.000Z

    We study the dynamics of thermonuclear flames propagating in fuel stirred by stochastic forcing. The fuel consists of carbon and oxygen in a state which is encountered in white dwarfs close to the Chandrasekhar limit. The level set method is applied to represent the flame fronts numerically. The computational domain for the numerical simulations is cubic, and periodic boundary conditions are imposed. The goal is the development of a suitable flame speed model for the small-scale dynamics of turbulent deflagration in thermonuclear supernovae. Because the burning process in a supernova explosion is transient and spatially inhomogeneous, the localised determination of subgrid scale closure parameters is essential. We formulate a semi-localised model based on the dynamical equation for the subgrid scale turbulence energy $k_{\\mathrm{sgs}}$. The turbulent flame speed $s_{\\mathrm{t}}$ is of the order $\\sqrt{2k_{\\mathrm{sgs}}}$. In particular, the subgrid scale model features a dynamic procedure for the calculation of the turbulent energy transfer from resolved toward subgrid scales, which has been successfully applied to combustion problems in engineering. The options of either including or suppressing inverse energy transfer in the turbulence production term are compared. In combination with the piece-wise parabolic method for the hydrodynamics, our results favour the latter option. Moreover, different choices for the constant of proportionality in the asymptotic flame speed relation, $s_{\\mathrm{t}}\\propto\\sqrt{2k_{\\mathrm{sgs}}}$, are investigated.

  11. Relativistic collapse and explosion of rotating supermassive stars with thermonuclear effects

    E-Print Network [OSTI]

    Pedro J. Montero; Hans-Thomas Janka; Ewald Mueller

    2012-02-01T23:59:59.000Z

    We present results of general relativistic simulations of collapsing supermassive stars with and without rotation using the two-dimensional general relativistic numerical code Nada, which solves the Einstein equations written in the BSSN formalism and the general relativistic hydrodynamics equations with high resolution shock capturing schemes. These numerical simulations use an equation of state which includes effects of gas pressure, and in a tabulated form those associated with radiation and the electron-positron pairs. We also take into account the effect of thermonuclear energy released by hydrogen and helium burning. We find that objects with a mass of 5x10^{5} solar mass and an initial metallicity greater than Z_{CNO}~0.007 do explode if non-rotating, while the threshold metallicity for an explosion is reduced to Z_{CNO}~0.001 for objects uniformly rotating. The critical initial metallicity for a thermonuclear explosion increases for stars with mass ~10^{6} solar mass. For those stars that do not explode we follow the evolution beyond the phase of black hole formation. We compute the neutrino energy loss rates due to several processes that may be relevant during the gravitational collapse of these objects. The peak luminosities of neutrinos and antineutrinos of all flavors for models collapsing to a BH are ~10^{55} erg/s. The total radiated energy in neutrinos varies between ~10^{56} ergs for models collapsing to a BH, and ~10^{45}-10^{46} ergs for models exploding.

  12. Thermonuclear Burning on the Accreting X-Ray Pulsar GRO J1744-28

    E-Print Network [OSTI]

    Lars Bildsten; Edward F. Brown

    1996-09-23T23:59:59.000Z

    We investigate the thermal stability of nuclear burning on the accreting X-ray pulsar GRO J1744-28. The neutron star's dipolar magnetic field is thermonuclear instabilities are unlikely causes of the hourly bursts seen at very high accretion rates. We then discuss how the stability of the thermonuclear burning depends on both the global accretion rate and the neutron star's magnetic field strength. We emphasize that the appearance of the instability (i.e., whether it looks like a Type I X-ray burst or a flare lasting a few minutes) will yield crucial information on the neutron star's surface magnetic field and the role of magnetic fields in convection. We suggest that a thermal instability in the accretion disk is the origin of the long (~300 days) outburst and that the recurrence time of these outbursts is >50 years. We also discuss the nature of the binary and point out that a velocity measurement of the stellar companion (most likely a Roche-lobe filling giant with m_K>17) will constrain the neutron star mass.

  13. * Department of Reactor Technology Rie#-*-ltt 2 Ris National Laboratory April 1978

    E-Print Network [OSTI]

    Storaae of Gas . Solar Heating and Underground Heat Storage . Wind Power Copies to Biblioteket 100 Technology within the following fields is described: . Reactor Engineering . Reactor Operation . Structural Simulators . Experimental Activation Measurements and Neutron Radiography at the DR 1 Reactor · Underground

  14. The Conception of Thermonuclear Reactor on the Principle of Gravitational Confinement of Dense High-temperature Plasma

    E-Print Network [OSTI]

    Fisenko, Stanislav

    2010-01-01T23:59:59.000Z

    The work of Fisenko S. I., & Fisenko I. S. (2009). The old and new concepts of physics, 6 (4), 495, shows the key fact of the existence of gravitational radiation as a radiation of the same level as electromagnetic. The obtained results strictly correspond to the framework of relativistic theory of gravitation and quantum mechanics. The given work contributes into further elaboration of the findings considering their application to dense high-temperature plasma of multiple-charge ions. This is due to quantitative character of electron gravitational emission spectrum such that amplification of gravitational emission may take place only in multiple-charge ion high-temperature plasma.

  15. The Conception of Thermonuclear Reactor on the Principle of Gravitational Confinement of Dense High-temperature Plasma

    E-Print Network [OSTI]

    Stanislav Fisenko; Igor Fisenko

    2010-06-27T23:59:59.000Z

    The work of Fisenko S. I., & Fisenko I. S. (2009). The old and new concepts of physics, 6 (4), 495, shows the key fact of the existence of gravitational radiation as a radiation of the same level as electromagnetic. The obtained results strictly correspond to the framework of relativistic theory of gravitation and quantum mechanics. The given work contributes into further elaboration of the findings considering their application to dense high-temperature plasma of multiple-charge ions. This is due to quantitative character of electron gravitational emission spectrum such that amplification of gravitational emission may take place only in multiple-charge ion high-temperature plasma.

  16. Thermonuclear yield of targets under the action of high-power short-wavelength (lambda< or =1. mu. ) lasers

    SciTech Connect (OSTI)

    Basov, N.G.; Gus'kov, S.Y.; Danilova, G.V.; Demchenko, N.N.; Zmitrenko, N.V.; Karpov, V.Y.; Mishchenko, T.V.; Rozanov, V.B.; Samarskii, A.A.

    1985-06-01T23:59:59.000Z

    A unified optimization scheme is used in a numerical calculation of the dependences of the thermonuclear yield of two-layer shell targets on the absorbed laser energy in the range 0.3--10 mJ for lasers emitting radiation of wavelengths shorter than 1 ..mu...

  17. Spreading of thermonuclear flames on the neutron star in SAX J1808.4-3658: an observational tool

    E-Print Network [OSTI]

    Sudip Bhattacharyya; Tod E. Strohmayer

    2006-04-03T23:59:59.000Z

    We analyse archival Rossi X-Ray Timing Explorer (RXTE) proportional counter array (PCA) data of thermonuclear X-ray bursts from the 2002 outburst of the accreting millisecond pulsar SAX J1808.4-3658. We present evidence of nonmonotonic variations of oscillation frequency during burst rise, and correlations among the time evolution of the oscillation frequency, amplitude, and the inferred burning region area. We also discuss that the amplitude and burning region area evolutions are consistent with thermonuclear flame spreading on the neutron star surface. Based on this discussion, we infer that for the 2002 Oct. 15 thermonuclear burst, the ignition likely occured in the mid-latitudes, the burning region took ~ 0.2 s to nearly encircle the equatorial region of the neutron star, and after that the lower amplitude oscillation originated from the remaining asymmetry of the burning front in the same hemisphere where the burst ignited. Our observational findings and theoretical discussion indicate that studies of the evolution of burst oscillation properties during burst rise can provide a powerful tool to understand thermonuclear flame spreading on neutron star surfaces under extreme physical conditions.

  18. Model based multivariable controller for large scale compression stations. Design and experimental validation on the LHC 18KW cryorefrigerator

    SciTech Connect (OSTI)

    Bonne, François; Bonnay, Patrick [INAC, SBT, UMR-E 9004 CEA/UJF-Grenoble, 17 rue des Martyrs, 38054 Grenoble (France); Alamir, Mazen [Gipsa-Lab, Control Systems Department, CNRS-University of Grenoble, 11, rue des Mathématiques, BP 46, 38402 Saint Martin d'Hères (France); Bradu, Benjamin [CERN, CH-1211 Genève 23 (Switzerland)

    2014-01-29T23:59:59.000Z

    In this paper, a multivariable model-based non-linear controller for Warm Compression Stations (WCS) is proposed. The strategy is to replace all the PID loops controlling the WCS with an optimally designed model-based multivariable loop. This new strategy leads to high stability and fast disturbance rejection such as those induced by a turbine or a compressor stop, a key-aspect in the case of large scale cryogenic refrigeration. The proposed control scheme can be used to have precise control of every pressure in normal operation or to stabilize and control the cryoplant under high variation of thermal loads (such as a pulsed heat load expected to take place in future fusion reactors such as those expected in the cryogenic cooling systems of the International Thermonuclear Experimental Reactor ITER or the Japan Torus-60 Super Advanced fusion experiment JT-60SA). The paper details how to set the WCS model up to synthesize the Linear Quadratic Optimal feedback gain and how to use it. After preliminary tuning at CEA-Grenoble on the 400W@1.8K helium test facility, the controller has been implemented on a Schneider PLC and fully tested first on the CERN's real-time simulator. Then, it was experimentally validated on a real CERN cryoplant. The efficiency of the solution is experimentally assessed using a reasonable operating scenario of start and stop of compressors and cryogenic turbines. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO.

  19. University Reactor Matching Grants Program

    SciTech Connect (OSTI)

    John Valentine; Farzad Rahnema; Said Abdel-Khalik

    2003-02-14T23:59:59.000Z

    During the 2002 Fiscal year, funds from the DOE matching grant program, along with matching funds from the industrial sponsors, have been used to support research in the area of thermal-hydraulics. Both experimental and numerical research projects have been performed. Experimental research focused on two areas: (1) Identification of the root cause mechanism for axial offset anomaly in pressurized water reactors under prototypical reactor conditions, and (2) Fluid dynamic aspects of thin liquid film protection schemes for inertial fusion reactor chambers. Numerical research focused on two areas: (1) Multi-fluid modeling of both two-phase and two-component flows for steam conditioning and mist cooling applications, and (2) Modeling of bounded Rayleigh-Taylor instability with interfacial mass transfer and fluid injection through a porous wall simulating the ''wetted wall'' protection scheme in inertial fusion reactor chambers. Details of activities in these areas are given.

  20. PPPL3171 Preprint Date: May 1996, UC421, 423, 427 Simulations of alpha particle ripple loss from the

    E-Print Network [OSTI]

    International Thermonuclear Experimental Reactor (ITER) [Plasma Physics and Controlled Nuclear Fusion Research from the International Thermonuclear Experimental Reactor M. H. Redi, R. V. Budny, D. C. McCune, C. O of the ripple minimum for D shaped ripple contours. In contrast to alpha loss simulations for the Tokamak Fusion

  1. U.S. to join research effort for fusion power Friday, January 31, 2003 file:///Macintosh%20HD/Desktop%20Folder/ITER%20Negotiations/MSNBC/

    E-Print Network [OSTI]

    , the International Thermonuclear Experimental Reactor, is a fusion research project that is already a joint operationU.S. to join research effort for fusion power Friday, January 31, 2003 file:///Macintosh%20HD view of the proposed International Thermonuclear Experimental Reactor, with a central containment

  2. TB, AP, UK, JPhysB/330302, 29/12/2009 IOP PUBLISHING JOURNAL OF PHYSICS B: ATOMIC, MOLECULAR AND OPTICAL PHYSICS

    E-Print Network [OSTI]

    Johnson, Walter R.

    Thermonuclear Experimental Reactor. (Some figures in this article are in colour only in the electronic version for future experiments at the International Thermonuclear Experimental Reactor (ITER). The effect, spectroscopy of highly charged tungsten ions relevant to fusion plasmas was recently discussed by Biedermann et

  3. Small-scale Interaction of Turbulence with Thermonuclear Flames in Type Ia Supernovae

    E-Print Network [OSTI]

    J. C. Niemeyer; W. K. Bushe; G. R. Ruetsch

    1999-05-07T23:59:59.000Z

    Microscopic turbulence-flame interactions of thermonuclear fusion flames occuring in Type Ia Supernovae were studied by means of incompressible direct numerical simulations with a highly simplified flame description. The flame is treated as a single diffusive scalar field with a nonlinear source term. It is characterized by its Prandtl number, Pr << 1, and laminar flame speed, S_L. We find that if S_L ~ u', where u' is the rms amplitude of turbulent velocity fluctuations, the local flame propagation speed does not significantly deviate from S_L even in the presence of velocity fluctuations on scales below the laminar flame thickness. This result is interpreted in the context of subgrid-scale modeling of supernova explosions and the mechanism for deflagration-detonation-transitions.

  4. Astrophysics Simulations from the ASC/Alliances Center for Astrophysical Thermonuclear Flashes

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The "Flash Center" works to solve the long-standing problem of thermonuclear flashes on the surfaces of compact stars such as neutron stars and white dwarfs, and in the interior of white dwarfs (i.e., Type I supernovae). The physical conditions, and many of the physical phenomena, are similar to those confronted by the Department of Energy Stockpile Stewardship program. The (fully ionized) plasmas are at very high temperatures and densities; and the physical problems of nuclear ignition, deflagration or detonation, turbulent mixing, and interface dynamics for complex multicomponent fluids are common to the weapons program. Because virtually every aspect of this problem represents a computational Grand Challenge, large-scale numerical simulations are at the heart of its resolution (Taken from Executive Summary page). More than 35 simulations and computer animations developed through research at the "Flash Center" are available here. Each .avi or .mov file also references the related research paper or presentation and provides a link.

  5. Oxygen emission in remnants of thermonuclear supernovae as a probe for their progenitor system

    E-Print Network [OSTI]

    Kosenko, D; Kromer, M; Blinnikov, S I; Pakmor, R; Kaastra, J S

    2014-01-01T23:59:59.000Z

    Recent progress in numerical simulations of thermonuclear supernova explosions brings up a unique opportunity in studying the progenitors of Type Ia supernovae. Coupling state-of-the-art explosion models with detailed hydrodynamical simulations of the supernova remnant evolution and the most up-to-date atomic data for X-ray emission calculations makes it possible to create realistic synthetic X-ray spectra for the supernova remnant phase. Comparing such spectra with high quality observations of supernova remnants could allow to constrain the explosion mechanism and the progenitor of the supernova. The present study focuses in particular on the oxygen emission line properties in young supernova remnants, since different explosion scenarios predict a different amount and distribution of this element. Analysis of the soft X-ray spectra from supernova remnants in the Large Magellanic Cloud and confrontation with remnant models for different explosion scenarios suggests that SNR 0509-67.5 could originate from a de...

  6. On the small-scale stability of thermonuclear flames in Type Ia supernovae

    E-Print Network [OSTI]

    F. K. Roepke; J. C. Niemeyer; W. Hillebrandt

    2003-05-02T23:59:59.000Z

    We present a numerical model which allows us to investigate thermonuclear flames in Type Ia supernova explosions. The model is based on a finite-volume explicit hydrodynamics solver employing PPM. Using the level-set technique combined with in-cell reconstruction and flux-splitting schemes we are able to describe the flame in the discontinuity approximation. We apply our implementation to flame propagation in Chandrasekhar-mass Type Ia supernova models. In particular we concentrate on intermediate scales between the flame width and the Gibson-scale, where the burning front is subject to the Landau-Darrieus instability. We are able to reproduce the theoretical prediction on the growth rates of perturbations in the linear regime and observe the stabilization of the flame in a cellular shape. The increase of the mean burning velocity due to the enlarged flame surface is measured. Results of our simulation are in agreement with semianalytical studies.

  7. Thermonuclear Burning Regimes and the Use of SNe Ia in Cosmology

    E-Print Network [OSTI]

    E. I. Sorokina; S. I. Blinnikov; O. S. Bartunov

    1999-10-02T23:59:59.000Z

    The calculations of the light curves of thermonuclear supernovae are carried out by a method of multi-group radiation hydrodynamics. The effects of spectral lines and expansion opacity are taken into account. The predictions for UBVI fluxes are given. The values of rise time for B and V bands found in our calculations are in good agreement with the observed values. We explain why our results for the rise time have more solid physical justification than those obtained by other authors. It is shown that small variations in the chemical composition of the ejecta, produced in the explosions with different regimes of nuclear burning, can influence drastically the light curve decline in the B band and, to a lesser extent, in the V band. We argue that recent results on positive cosmological constant Lambda, found from the high redshift supernova observations, could be wrong in the case of possible variations of the preferred mode of nuclear burning in the earlier Universe.

  8. Registration of the First Thermonuclear X-ray Burst from AX J1754.2-2754

    E-Print Network [OSTI]

    I. V. Chelovekov; S. A. Grebenev

    2007-10-30T23:59:59.000Z

    During the analysis of the INTEGRAL observatory archival data we found a powerful X-ray burst, registered by JEM-X and IBIS/ISGRI telescopes on April 16, 2005 from a weak and poorly known source AX J1754.2-2754. Analysis of the burst profiles and spectrum shows, that it was a type I burst, which result from thermonuclear explosion on the surface of nutron star. It means that we can consider AX J1754.2-2754 as an X-ray burster. Certain features of burst profile at its initial stage witness of a radiation presure driven strong expansion and a corresponding cooling of the nutron star photosphere. Assuming, that the luminosity of the source at this phase was close to the Eddington limit, we estimated the distance to the burst source d=6.6+/-0.3 kpc (for hidrogen atmosphere of the neutron star) and d=9.2+/-0.4 kpc (for helium atmosphere).

  9. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova

    E-Print Network [OSTI]

    Geier, S; Ziegerer, E; Kupfer, T; Heber, U; Irrgang, A; Wang, B; Liu, Z; Han, Z; Sesar, B; Levitan, D; Kotak, R; Magnier, E; Smith, K; Burgett, W S; Chambers, K; Flewelling, H; Kaiser, N; Wainscoat, R; Waters, C

    2015-01-01T23:59:59.000Z

    Hypervelocity stars (HVS) travel with velocities so high, that they exceed the escape velocity of the Galaxy. Several acceleration mechanisms have been discussed. Only one HVS (US 708, HVS 2) is a compact helium star. Here we present a spectroscopic and kinematic analysis of US\\,708. Travelling with a velocity of $\\sim1200\\,{\\rm km\\,s^{-1}}$, it is the fastest unbound star in our Galaxy. In reconstructing its trajectory, the Galactic center becomes very unlikely as an origin, which is hardly consistent with the most favored ejection mechanism for the other HVS. Furthermore, we discovered US\\,708 to be a fast rotator. According to our binary evolution model it was spun-up by tidal interaction in a close binary and is likely to be the ejected donor remnant of a thermonuclear supernova.

  10. Thermonuclear Processes for Three Body System in the Potential Cluster Model

    E-Print Network [OSTI]

    Dubovichenko, S B

    2015-01-01T23:59:59.000Z

    The manuscript is devoted to the description of the results obtained in the frame of the modified potential cluster model with the classification of states according to Young tableaux for neutron and proton radiative capture processes on 2H at thermal and astrophysical energies. It demonstrates methods of application that were obtained on the basis of phase shift analysis and characteristics of the bound states of 2H potentials for consideration of the radiative capture processes. First reaction of the proton capture directly takes part in the pp solar cycle, where it is the second reaction. The neutron capture is not a part of usual thermonuclear cycles in the Sun and stars, but can take part in the processes of primordial nucleosynthesis, following at formation and evolution of our entire Universe.

  11. Thermonuclear Processes for Three Body System in the Potential Cluster Model

    E-Print Network [OSTI]

    S. B. Dubovichenko; A. V. Dzhazairov-Kakhramanov

    2015-04-19T23:59:59.000Z

    The manuscript is devoted to the description of the results obtained in the frame of the modified potential cluster model with the classification of states according to Young tableaux for neutron and proton radiative capture processes on 2H at thermal and astrophysical energies. It demonstrates methods of application that were obtained on the basis of phase shift analysis and characteristics of the bound states of 2H potentials for consideration of the radiative capture processes. First reaction of the proton capture directly takes part in the pp solar cycle, where it is the second reaction. The neutron capture is not a part of usual thermonuclear cycles in the Sun and stars, but can take part in the processes of primordial nucleosynthesis, following at formation and evolution of our entire Universe.

  12. Analysis of the Thermonuclear Instability including Low-Power ICRH Minority Heating in IGNITOR

    E-Print Network [OSTI]

    Cardinali, Alessandro

    2014-01-01T23:59:59.000Z

    The nonlinear thermal balance equation for classical plasma in a toroidal geometry is analytically and numerically investigated including ICRH power. The determination of the equilibrium temperature and the analysis of the stability of the solution are performed by solving the energy balance equation that includes the transport relations obtained by the kinetic theory. An estimation of the confinement time is also provided. We show that the ICRH heating in the IGNITOR experiment, among other applications, is expected to stabilize the power of the thermonuclear burning by automatic regulation of the RF coupled power. Here a scenario is considered where IGNITOR is led to operate in a slightly sub-critical regime by adding a small fraction of ${}^3He$ to the nominal 50-50 Deuterium-Tritium mixture. The difference between power lost and alpha heating is compensated by additional ICRH heating, which should be able to increase the global plasma temperature via collisions between ${}^3He$ minority and the background...

  13. Spiral Disk Instability Can Drive Thermonuclear Explosions in Binary White Dwarf Mergers

    E-Print Network [OSTI]

    Kashyap, Rahul; García-Berro, Enrique; Aznar-Siguán, Gabriela; Ji, Suoqing; Lorén-Aguilar, Pablo

    2015-01-01T23:59:59.000Z

    Thermonuclear, or Type Ia supernovae (SNe Ia), originate from the explosion of carbon-oxygen white dwarfs, and serve as standardizable cosmological candles. However, despite their importance, the nature of the progenitor systems which give rise to SNe Ia has not been hitherto elucidated. Observational evidence favors the double-degenerate channel, in which merging white dwarf binaries lead to SNe Ia. Furthermore, significant discrepancies exist between observations and theory, and to date, there has been no self-consistent merger model which yields a SNe Ia. Here we show that a spiral mode instability in the accretion disk formed during a binary white dwarf merger leads to a detonation on a dynamical timescale. This mechanism sheds light on how white dwarf mergers may frequently yield SNe Ia.

  14. RELATIVISTIC COLLAPSE AND EXPLOSION OF ROTATING SUPERMASSIVE STARS WITH THERMONUCLEAR EFFECTS

    SciTech Connect (OSTI)

    Montero, Pedro J.; Janka, Hans-Thomas; Mueller, Ewald, E-mail: montero@mpa-garching.mpg.de [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)

    2012-04-10T23:59:59.000Z

    We present results of general relativistic simulations of collapsing supermassive stars with and without rotation using the two-dimensional general relativistic numerical code Nada, which solves the Einstein equations written in the BSSN formalism and the general relativistic hydrodynamic equations with high-resolution shock-capturing schemes. These numerical simulations use an equation of state that includes the effects of gas pressure and, in a tabulated form, those associated with radiation and the electron-positron pairs. We also take into account the effect of thermonuclear energy released by hydrogen and helium burning. We find that objects with a mass of Almost-Equal-To 5 Multiplication-Sign 10{sup 5} M{sub Sun} and an initial metallicity greater than Z{sub CNO} Almost-Equal-To 0.007 do explode if non-rotating, while the threshold metallicity for an explosion is reduced to Z{sub CNO} Almost-Equal-To 0.001 for objects uniformly rotating. The critical initial metallicity for a thermonuclear explosion increases for stars with a mass Almost-Equal-To 10{sup 6} M{sub Sun }. For those stars that do not explode, we follow the evolution beyond the phase of black hole (BH) formation. We compute the neutrino energy loss rates due to several processes that may be relevant during the gravitational collapse of these objects. The peak luminosities of neutrinos and antineutrinos of all flavors for models collapsing to a BH are L{sub {nu}} {approx} 10{sup 55} erg s{sup -1}. The total radiated energy in neutrinos varies between E{sub {nu}} {approx} 10{sup 56} erg for models collapsing to a BH and E{sub {nu}} {approx} 10{sup 45}-10{sup 46} erg for models exploding.

  15. SAMPLING DECISIONS IN OPTIMUM EXPERIMENTAL DESIGN IN ...

    E-Print Network [OSTI]

    ssager

    on a fixed time horizon T = [0,tf] with differential states y : T ?? Rny , fixed model ...... mal experimental design of a catalytic fixed bed reactor, in Proceedings of ...

  16. Nuclear reactor engineering

    SciTech Connect (OSTI)

    Glasstone, S.; Sesonske, A.

    1981-01-01T23:59:59.000Z

    Chapters are presented concerning energy from nuclear fission; nuclear reactions and radiations; diffusion and slowing-down of neutrons; principles of reactor analysis; nuclear reactor kinetics and control; energy removal; non-fuel reactor materials; the reactor fuel system; radiation protection and environmental effects; nuclear reactor shielding; nuclear reactor safety; and power reactor systems.

  17. Research project -Master Thesis Investigation of mixed rare earth

    E-Print Network [OSTI]

    's) to fusion devices such as the International Thermonuclear Experimental Reactor (ITER) to superconducting emission-free energy by means of supercon- ducting generators for windmills, fusion reactors etc

  18. REACTOR ENGINEERING DIVISION QUARTERLY REPORT FOR DECEMBER 1...

    Office of Scientific and Technical Information (OSTI)

    reactor (physics, thermal analysis, and experimental and development program); corrosion of Al coating: irradiation of wax and lubricants; effect of long-term irradiation on...

  19. Pyroprocessing of oxidized sodium-bonded fast reactor fuel - An experimental study of treatment options for degraded EBR-II fuel

    SciTech Connect (OSTI)

    Hermann, S.D.; Gese, N.J. [Separations Department, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415 (United States); Wurth, L.A. [Zinc Air Inc., 5314-A US Hwy 2 West, Columbia Falls, MT 59912 (United States)

    2013-07-01T23:59:59.000Z

    An experimental study was conducted to assess pyrochemical treatment options for degraded EBR-II fuel. As oxidized material, the degraded fuel would need to be converted back to metal to enable electrorefining within an existing electro-metallurgical treatment process. A lithium-based electrolytic reduction process was studied to assess the efficacy of converting oxide materials to metal with a particular focus on the impact of zirconium oxide and sodium oxide on this process. Bench-scale electrolytic reduction experiments were performed in LiCl-Li{sub 2}O at 650 C. degrees with combinations of manganese oxide (used as a surrogate for uranium oxide), zirconium oxide, and sodium oxide. In the absence of zirconium or sodium oxide, the electrolytic reduction of MnO showed nearly complete conversion to metal. The electrolytic reduction of a blend of MnO-ZrO{sub 2} in LiCl - 1 wt% Li{sub 2}O showed substantial reduction of manganese, but only 8.5% of the zirconium was found in the metal phase. The electrolytic reduction of the same blend of MnO-ZrO{sub 2} in LiCl - 1 wt% Li{sub 2}O - 6.2 wt% Na{sub 2}O showed substantial reduction of manganese, but zirconium reduction was even less at 2.4%. This study concluded that ZrO{sub 2} cannot be substantially reduced to metal in an electrolytic reduction system with LiCl - 1 wt% Li{sub 2}O at 650 C. degrees due to the perceived preferential formation of lithium zirconate. This study also identified a possible interference that sodium oxide may have on the same system by introducing a parasitic and cyclic reaction of dissolved sodium metal between oxidation at the anode and reduction at the cathode. When applied to oxidized sodium-bonded EBR-II fuel (e.g., U-10Zr), the prescribed electrolytic reduction system would not be expected to substantially reduce zirconium oxide, and the accumulation of sodium in the electrolyte could interfere with the reduction of uranium oxide, or at least render it less efficient.

  20. Bioconversion reactor

    DOE Patents [OSTI]

    McCarty, Perry L. (Stanford, CA); Bachmann, Andre (Palo Alto, CA)

    1992-01-01T23:59:59.000Z

    A bioconversion reactor for the anaerobic fermentation of organic material. The bioconversion reactor comprises a shell enclosing a predetermined volume, an inlet port through which a liquid stream containing organic materials enters the shell, and an outlet port through which the stream exits the shell. A series of vertical and spaced-apart baffles are positioned within the shell to force the stream to flow under and over them as it passes from the inlet to the outlet port. The baffles present a barrier to the microorganisms within the shell causing them to rise and fall within the reactor but to move horizontally at a very slow rate. Treatment detention times of one day or less are possible.

  1. Catalytic reactor

    DOE Patents [OSTI]

    Aaron, Timothy Mark (East Amherst, NY); Shah, Minish Mahendra (East Amherst, NY); Jibb, Richard John (Amherst, NY)

    2009-03-10T23:59:59.000Z

    A catalytic reactor is provided with one or more reaction zones each formed of set(s) of reaction tubes containing a catalyst to promote chemical reaction within a feed stream. The reaction tubes are of helical configuration and are arranged in a substantially coaxial relationship to form a coil-like structure. Heat exchangers and steam generators can be formed by similar tube arrangements. In such manner, the reaction zone(s) and hence, the reactor is compact and the pressure drop through components is minimized. The resultant compact form has improved heat transfer characteristics and is far easier to thermally insulate than prior art compact reactor designs. Various chemical reactions are contemplated within such coil-like structures such that as steam methane reforming followed by water-gas shift. The coil-like structures can be housed within annular chambers of a cylindrical housing that also provide flow paths for various heat exchange fluids to heat and cool components.

  2. Advanced Safeguards Approaches for New Fast Reactors

    SciTech Connect (OSTI)

    Durst, Philip C.; Therios, Ike; Bean, Robert; Dougan, A.; Boyer, Brian; Wallace, Rick L.; Ehinger, Michael H.; Kovacic, Don N.; Tolk, K.

    2007-12-15T23:59:59.000Z

    This third report in the series reviews possible safeguards approaches for new fast reactors in general, and the ABR in particular. Fast-neutron spectrum reactors have been used since the early 1960s on an experimental and developmental level, generally with fertile blanket fuels to “breed” nuclear fuel such as plutonium. Whether the reactor is designed to breed plutonium, or transmute and “burn” actinides depends mainly on the design of the reactor neutron reflector and the whether the blanket fuel is “fertile” or suitable for transmutation. However, the safeguards issues are very similar, since they pertain mainly to the receipt, shipment and storage of fresh and spent plutonium and actinide-bearing “TRU”-fuel. For these reasons, the design of existing fast reactors and details concerning how they have been safeguarded were studied in developing advanced safeguards approaches for the new fast reactors. In this regard, the design of the Experimental Breeder Reactor-II “EBR-II” at the Idaho National Laboratory (INL) was of interest, because it was designed as a collocated fast reactor with a pyrometallurgical reprocessing and fuel fabrication line – a design option being considered for the ABR. Similarly, the design of the Fast Flux Facility (FFTF) on the Hanford Site was studied, because it was a successful prototype fast reactor that ran for two decades to evaluate fuels and the design for commercial-scale fast reactors.

  3. Igniting the Light Elements: The Los Alamos Thermonuclear Weapon Project, 1942-1952

    SciTech Connect (OSTI)

    Anne C. Fitzpatrick

    1999-07-01T23:59:59.000Z

    The American system of nuclear weapons research and development was conceived and developed not as a result of technological determinism, but by a number of individual architects who promoted the growth of this large technologically-based complex. While some of the technological artifacts of this system, such as the fission weapons used in World War II, have been the subject of many historical studies, their technical successors--fusion (or hydrogen) devices--are representative of the largely unstudied highly secret realms of nuclear weapons science and engineering. In the postwar period a small number of Los Alamos Scientific Laboratory's staff and affiliates were responsible for theoretical work on fusion weapons, yet the program was subject to both the provisions and constraints of the US Atomic Energy Commission, of which Los Alamos was a part. The Commission leadership's struggle to establish a mission for its network of laboratories, least of all to keep them operating, affected Los Alamos's leaders' decisions as to the course of weapons design and development projects. Adapting Thomas P. Hughes's ''large technological systems'' thesis, I focus on the technical, social, political, and human problems that nuclear weapons scientists faced while pursuing the thermonuclear project, demonstrating why the early American thermonuclear bomb project was an immensely complicated scientific and technological undertaking. I concentrate mainly on Los Alamos Scientific Laboratory's Theoretical, or T, Division, and its members' attempts to complete an accurate mathematical treatment of the ''Super''--the most difficult problem in physics in the postwar period--and other fusion weapon theories. Although tackling a theoretical problem, theoreticians had to address technical and engineering issues as well. I demonstrate the relative value and importance of H-bomb research over time in the postwar era to scientific, politician, and military participants in this project. I analyze how and when participants in the H-bomb project recognized both blatant and subtle problems facing the project, how scientists solved them, and the relationship this process had to official nuclear weapons policies. Consequently, I show how the practice of nuclear weapons science in the postwar period became an extremely complex, technologically-based endeavor.

  4. Failure of a neutrino-driven explosion after core-collapse may lead to a thermonuclear supernova

    E-Print Network [OSTI]

    Kushnir, Doron

    2014-01-01T23:59:59.000Z

    We demonstrate that $\\sim10$ seconds after core-collapse of a massive star, a thermonuclear explosion of the outer shells is possible for some (tuned) initial density and composition profiles, assuming the neutrinos failed to explode the star. The explosion may lead to a successful supernova, as first suggested by Burbidge, Burbidge, Fowler and Hoyle (1957). We perform a series of one-dimensional (1D) calculations of collapsing massive stars with simplified initial density profiles (similar to the results of stellar evolution calculations) and various compositions (not similar to 1D stellar evolution calculations). We assume that the neutrinos escaped with negligible effect on the outer layers, which inevitably collapse. As the shells collapse, they compress and heat up adiabatically, enhancing the rate of thermonuclear burning. In some cases, where significant shells of mixed helium and oxygen are present with pre-collapsed burning times of $\\lesssim100\\,\\textrm{s}$ ($\\approx10$ times the free-fall time), a ...

  5. NACRE II: an update of the NACRE compilation of charged-particle-induced thermonuclear reaction rates for nuclei with mass number $A < 16$

    E-Print Network [OSTI]

    Yi Xu; Kohji Takahashi; Stephane Goriely; Marcel Arnould; Masahisa Ohta; Hiroaki Utsunomiya

    2013-10-26T23:59:59.000Z

    An update of the NACRE compilation [Angulo et al., Nucl. Phys. A 656 (1999) 3] is presented. This new compilation, referred to as NACRE II, reports thermonuclear reaction rates for 34 charged-particle induced, two-body exoergic reactions on nuclides with mass number $A<16$, of which fifteen are particle-transfer reactions and the rest radiative capture reactions. When compared with NACRE, NACRE II features in particular (1) the addition to the experimental data collected in NACRE of those reported later, preferentially in the major journals of the field by early 2013, and (2) the adoption of potential models as the primary tool for extrapolation to very low energies of astrophysical $S$-factors, with a systematic evaluation of uncertainties. As in NACRE, the rates are presented in tabular form for temperatures in the $10^{6}$ $\\simeq\\leq$ T $\\leq$ $10^{10}$ K range. Along with the 'adopted' rates, their low and high limits are provided. The new rates are available in electronic form as part of the Brussels Library (BRUSLIB) of nuclear data. The NACRE II rates also supersede the previous NACRE rates in the Nuclear Network Generator (NETGEN) for astrophysics. [http://www.astro.ulb.ac.be/databases.html.

  6. Reactor physics project progress report no. 2

    E-Print Network [OSTI]

    Driscoll, Michael J.

    1969-01-01T23:59:59.000Z

    This is the second annual report in an experimental and theoretical program to develop and apply single and few element heterogeneous methods for the determination of reactor lattice parameters. During the period covered ...

  7. ON THE COOLING TAILS OF THERMONUCLEAR X-RAY BURSTS: THE IGR J17480-2446 LINK

    SciTech Connect (OSTI)

    Linares, M.; Chakrabarty, D. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Van der Klis, M. [Astronomical Institute 'Anton Pannekoek', University of Amsterdam and Center for High-Energy Astrophysics, P.O. Box 94249, 1090 GE Amsterdam (Netherlands)

    2011-06-01T23:59:59.000Z

    The neutron star transient and 11 Hz X-ray pulsar IGR J17480-2446, recently discovered in the globular cluster Terzan 5, showed unprecedented bursting activity during its 2010 October-November outburst. We analyzed all X-ray bursts detected with the Rossi X-ray Timing Explorer and find strong evidence that they all have a thermonuclear origin, despite the fact that many do not show the canonical spectral softening along the decay imprinted on type I X-ray bursts by the cooling of the neutron star photosphere. We show that the persistent-to-burst power ratio is fully consistent with the accretion-to-thermonuclear efficiency ratio along the whole outburst, as is typical for type I X-ray bursts. The burst energy, peak luminosity, and daily-averaged spectral profiles all evolve smoothly throughout the outburst, in parallel with the persistent (non-burst) luminosity. We also find that the peak-burst to persistent luminosity ratio determines whether or not cooling is present in the bursts from IGR J17480-2446, and argue that the apparent lack of cooling is due to the 'non-cooling' bursts having both a lower peak temperature and a higher non-burst (persistent) emission. We conclude that the detection of cooling along the decay is a sufficient, but not a necessary condition to identify an X-ray burst as thermonuclear. Finally, we compare these findings with X-ray bursts from other rapidly accreting neutron stars.

  8. Neutronic reactor

    DOE Patents [OSTI]

    Wende, Charles W. J. (Augusta, GA); Babcock, Dale F. (Wilmington, DE); Menegus, Robert L. (Wilmington, DE)

    1983-01-01T23:59:59.000Z

    A nuclear reactor includes an active portion with fissionable fuel and neutron moderating material surrounded by neutron reflecting material. A control element in the active portion includes a group of movable rods constructed of neutron-absorbing material. Each rod is movable with respect to the other rods to vary the absorption of neutrons and effect control over neutron flux.

  9. Relics of metal-free low mass stars exploding as thermonuclear supernovae

    E-Print Network [OSTI]

    Tsujimoto, T; Tsujimoto, Takuji; Shigeyama, Toshikazu

    2006-01-01T23:59:59.000Z

    Renewed interest in the first stars that were formed in the universe has led to the discovery of extremely iron-poor stars. Since several competing scenarios exist, our understanding of the mass range that determines the observed elemental abundances remains unclear. In this study, we consider three well-studied metal-poor stars in terms of the theoretical supernovae (SNe) model. Our results suggest that the observed abundance patterns in the metal-poor star BD +80 245 and the pair of stars HD 134439/40 agree strongly with the theoretical possibility that these stars inherited their heavy element abundance patterns from SNe initiated by thermonuclear runaways in the degenerate carbon-oxygen cores of primordial asymptotic giant branch stars with \\~3.5-5 solar masses. Recent theoretical calculations have predicted that such SNe could be originated from metal-free stars in the intermediate mass range. On the other hand, intermediate mass stars containing some metals would end their lives as white dwarfs after ex...

  10. Thermonuclear explosions of Chandrasekhar-mass C+O white dwarfs

    E-Print Network [OSTI]

    M. Reinecke; W. Hillebrandt; J. C. Niemeyer

    1999-04-23T23:59:59.000Z

    First results of simulations are presented which compute the dynamical evolution of a Chandrasekhar-mass white dwarf, consisting of equal amounts of carbon and oxygen, from the onset of violent thermonuclear burning, by means of a new two-dimensional numerical code. Since in the interior of such a massive white dwarf nuclear burning progresses on microscopic scales as a sharp discontinuity, a so-called flamelet, which cannot be resolved by any numerical scheme, and since on macroscopic scales the burning front propagates due to turbulence, we make an attempt to model both effects explicitly in the framework of a finite-volume hydrodynamics code. Turbulence is included by a sub-grid model, following the spirit of large eddy simulations, and the well-localized burning front is treated by means of a level set, which allows us to compute the geometrical structure of the front more accurately than with previous methods. The only free parameters of our simulations are the location and the amount of nuclear fuel that is ignited as an initial perturbation. We find that models in which explosive carbon burning is ignited at the center remain bound by the time the front reaches low densities, where we stopped the computations because our description of combustion is no longer applicable. In contrast, off-center ignition models give rise to explosions which, however, are still too weak for typical Type Ia supernovae. Possible reasons for this rather disappointing result are discussed.

  11. On the applicability of the level set method beyond the flamelet regime in thermonuclear supernova simulations

    E-Print Network [OSTI]

    W. Schmidt

    2007-01-15T23:59:59.000Z

    In thermonuclear supernovae, intermediate mass elements are mostly produced by distributed burning provided that a deflagration to detonation transition does not set in. Apart from the two-dimensional study by Roepke & Hillebrandt (2005), very little attention has been payed so far to the correct treatment of this burning regime in numerical simulations. In this article, the physics of distributed burning is reviewed from the literature on terrestrial combustion and differences which arise from the very small Prandtl numbers encountered in degenerate matter are pointed out. Then it is shown that the level set method continues to be applicable beyond the flamelet regime as long as the width of the flame brush does not become smaller than the numerical cutoff length. Implementing this constraint with a simple parameterisation of the effect of turbulence onto the energy generation rate, the production of intermediate mass elements increases substantially compared to previous simulations, in which the burning process was stopped once the mass density dropped below 10^7 g/cm^3. Although these results depend on the chosen numerical resolution, an improvement of the constraints on the the total mass of burning products in the pure deflagration scenario can be achieved.

  12. Rotational effects in thermonuclear Type I Bursts: equatorial crossing and directionality of flame spreading

    E-Print Network [OSTI]

    Cavecchi, Yuri; Levin, Yuri; Braithwaite, Jonathan

    2014-01-01T23:59:59.000Z

    In a previous study on thermonuclear (Type I) Bursts on accreting neutron stars we addressed and demonstrated the importance of the effects of rotation, through the Coriolis force, on the propagation of the burning flame. However, that study only analysed cases of longitudinal propagation, where the Coriolis force coefficient $2\\Omega\\cos\\theta$ was constant. In this paper, we study the effects of rotation on propagation in the meridional (latitudinal) direction, where the Coriolis force changes from its maximum at the poles to zero at the equator. We find that the zero Coriolis force at the equator, while affecting the structure of the flame, does not prevent its propagation from one hemisphere to another. We also observe structural differences between the flame propagating towards the equator and that propagating towards the pole, the second being faster. In the light of the recent discovery of the low spin frequency of burster IGR~J17480-2446 rotating at 11 Hz (for which Coriolis effects should be negligib...

  13. Evidence for enhanced persistent emission during sub-Eddington thermonuclear bursts

    E-Print Network [OSTI]

    Worpel, Hauke; Price, Daniel J

    2015-01-01T23:59:59.000Z

    The standard approach for time-resolved X-ray spectral analysis of thermonuclear bursts involves subtraction of the pre-burst emission as background. This approach implicitly assumes that the persistent flux remains constant throughout the burst. We reanalyzed 332 photospheric radius expansion bursts observed from 40 sources by the Rossi X-ray Timing Explorer, introducing a multiplicative factor $f_a$ to the persistent emission contribution in our spectral fits. We found that for the majority of spectra the best-fit value of $f_a$ is significantly greater than 1, suggesting that the persistent emission typically increases during a burst. Elevated $f_a$ values were not found solely during the radius expansion interval of the burst, but were also measured in the cooling tail. The modified model results in a lower average value of the $\\chi^2$ fit statistic, indicating superior spectral fits, but not yet to the level of formal statistical consistency for all the spectra. We interpret the elevated $f_a$ values as...

  14. Thermonuclear reaction rate of 18O(p,gamma)19F

    E-Print Network [OSTI]

    M. Q. Buckner; C. Iliadis; J. M. Cesaratto; C. Howard; T. B. Clegg; A. E. Champagne; S. Daigle

    2012-12-05T23:59:59.000Z

    For stars between 0.8-8.0 solar masses, nucleosynthesis enters its final phase during the asymptotic giant branch (AGB) stage. During this evolutionary period, grain condensation occurs in the stellar atmosphere, and the star experiences significant mass loss. The production of presolar grains can often be attributed to this unique stellar environment. A subset of presolar oxide grains features dramatic 18O depletion that cannot be explained by the standard AGB star burning stages and dredge-up models. An extra mixing process, referred to as "cool bottom processing" (CBP), was proposed for low-mass AGB stars. The 18O depletion observed within certain stellar environments and within presolar grain samples may result from the 18O+p processes during CBP. We report here on a study of the 18O(p,gamma)19F reaction at low energies. Based on our new results, we found that the resonance at Er = 95 keV (lab) has a negligible affect on the reaction rate at the temperatures associated with CBP. We also determined that the direct capture S-factor is almost a factor of 2 lower than the previously recommended value at low energies. An improved thermonuclear reaction rate for 18O(p,gamma)19F is presented.

  15. The progenitors of core-collapse supernovae suggest thermonuclear origin for the explosions

    E-Print Network [OSTI]

    Kushnir, Doron

    2015-01-01T23:59:59.000Z

    Core-collapse supernovae (CCSNe) are the explosions of massive stars following the collapse of the stars' iron cores. Poznanski (2013) has recently suggested an observational correlation between the ejecta velocities and the inferred masses of the red supergiant progenitors of type II-P explosions, which implies that the kinetic energy of the ejecta ($E_{\\textrm{kin}}$) increases with the mass of the progenitor. I point out that the same conclusion can be reached from the model-free observed correlation between the ejected $^{56}$Ni masses ($M_{\\textrm{Ni}}$) and the luminosities of the progenitors for type II supernovae, which was reported by Fraser et al. (2011). This correlation is in an agreement with the predictions of the collapse-induced thermonuclear explosions (CITE) for CCSNe and in a possible contradiction with the predictions of the neutrino mechanism. I show that a correlation between $M_{\\textrm{Ni}}$ and $E_{\\textrm{kin}}$ holds for all types of CCSNe (including type Ibc). This correlation sugg...

  16. Evidence of thermonuclear flame spreading on neutron stars from burst rise oscillations

    E-Print Network [OSTI]

    Chakraborty, Manoneeta

    2014-01-01T23:59:59.000Z

    Burst oscillations during the rising phases of thermonuclear X-ray bursts are usually believed to originate from flame spreading on the neutron star surface. However, the decrease of fractional oscillation amplitude with rise time, which provides a main observational support for the flame spreading model, have so far been reported from only a few bursts. Moreover, the non-detection and intermittent detections of rise oscillations from many bursts are not yet understood considering the flame spreading scenario. Here, we report the decreasing trend of fractional oscillation amplitude from an extensive analysis of a large sample of Rossi X-ray Timing Explorer Proportional Counter Array bursts from ten neutron star low-mass X-ray binaries. This trend is 99.99% significant for the best case, which provides, to the best of our knowledge, by far the strongest evidence of such trend. Moreover, it is important to note that an opposite trend is not found from any of the bursts. The concave shape of the fractional ampli...

  17. Screened thermonuclear reactions and predictive stellar evolution of detached double-lined eclipsing binaries

    E-Print Network [OSTI]

    Theodore Liolios; Theocharis Kosmas

    2005-07-06T23:59:59.000Z

    The low energy fusion cross sections of charged-particle nuclear reactions (and the respective reaction rates) in stellar plasmas are enhanced due to plasma screening effects. We study the impact of those effects on predictive stellar evolution simulations for detached double-lined eclipsing binaries. We follow the evolution of binary systems (pre-main sequence or main sequence stars) with precisely determined radii and masses from 1.1Mo to 23Mo (from their birth until their present state). The results indicate that all the discrepancies between the screened and unscreened models (in terms of luminosity, stellar radius, and effective temperature) are within the observational uncertainties. Moreover, no nucleosynthetic or compositional variation was found due to screening corrections. Therefore all thermonuclear screening effects on the charged-particle nuclear reactions that occur in the binary stars considered in this work (from their birth until their present state) can be totally disregarded. In other words, all relevant charged-particle nuclear reactions can be safely assumed to take place in a vacuum, thus simplifying and accelerating the simulation processes.

  18. MA50177: Scientific Computing Nuclear Reactor Simulation Generalised Eigenvalue Problems

    E-Print Network [OSTI]

    Wirosoetisno, Djoko

    MA50177: Scientific Computing Case Study Nuclear Reactor Simulation ­ Generalised Eigenvalue of a malfunction or of an accident experimentally, the numerical simulation of nuclear reactors is of utmost balance in a nuclear reactor are the two-group neutron diffusion equations -div (K1 u1) + (a,1 + s) u1 = 1

  19. Seminar 1b-1.letnik, II.stopnja Deuterium depth profiling with

    E-Print Network [OSTI]

    ?umer, Slobodan

    of most critical issues in the construction of thermonuclear reactor based on magnetic confiment of the deuterium-tritium operation of International Thermonuclear Experimental Reactor (ITER). ITER walls-facing materials in nuclear fusion research resulted in an increasing interest in quantitative profiling

  20. Doubts Rise Over the Great Nuclear Promise Julio Godoy

    E-Print Network [OSTI]

    that a thermonuclear reactor poses three technical problems: production of the elements to undergo fusion (deuterium over a decision to base the International Thermonuclear Experimental Reactor (ITER) in France seems to introduce new nuclear technology. It will seek a nuclear fusion of two hydrogen isotopes (deuterium which

  1. Search for sterile neutrinos at reactors

    E-Print Network [OSTI]

    Yasuda, Osamu

    2011-01-01T23:59:59.000Z

    The sensitivity to the sterile neutrino mixing at very short baseline reactor neutrino experiments is investigated. In the case of conventional (thermal neutron) reactors it is found that the sensitivity is lost for $\\Delta m^2 \\gtrsim$ 1 eV$^2$ due to smearing of the reactor core size. On the other hand, in the case of an experimental fast neutron reactor Joyo, because of its small size, sensitivity to $\\sin^22\\theta_{14}$ can be as good as 0.03 for $\\Delta m^2 \\sim$ several eV$^2$ with the Bugey-like detector setup.

  2. Frontier of Fusion Research: Path to the Steady State Fusion Reactor by Large Helical Device

    SciTech Connect (OSTI)

    Motojima, Osamu [National Institute for Fusion Science, Toki-shi, Gifu-ken, 509-5292 (Japan)

    2006-12-01T23:59:59.000Z

    The ITER, the International Thermonuclear Experimental Reactor, which will be built in Cadarache in France, has finally started this year, 2006. Since the thermal energy produced by fusion reactions divided by the external heating power, i.e., the Q value, will be larger than 10, this is a big step of the fusion research for half a century trying to tame the nuclear fusion for the 6.5 Billion people on the Earth. The source of the Sun's power is lasting steadily and safely for 8 Billion years. As a potentially safe environmentally friendly and economically competitive energy source, fusion should provide a sustainable future energy supply for all mankind for ten thousands of years. At the frontier of fusion research important milestones are recently marked on a long road toward a true prototype fusion reactor. In its own merits, research into harnessing turbulent burning plasmas and thereby controlling fusion reaction, is one of the grand challenges of complex systems science.After a brief overview of a status of world fusion projects, a focus is given on fusion research at the National Institute for Fusion Science (NIFS) in Japan, which is playing a role of the Inter University Institute, the coordinating Center of Excellence for academic fusion research and by the Large Helical Device (LHD), the world's largest superconducting heliotron device, as a National Users' facility. The current status of LHD project is presented focusing on the experimental program and the recent achievements in basic parameters and in steady state operations. Since, its start in a year 1998, a remarkable progress has presently resulted in the temperature of 140 Million degree, the highest density of 500 Thousand Billion/cc with the internal density barrier (IDB) and the highest steady average beta of 4.5% in helical plasma devices and the largest total input energy of 1.6 GJ, in all magnetic confinement fusion devices. Finally, a perspective is given of the ITER Broad Approach program as an integrated part of ITER and Development of Fusion Energy project Agreement. Moreover, the relationship with the NIFS' new parent organization the National Institutes of Natural Sciences and with foreign research institutions is briefly explained.

  3. Reactor D and D at Argonne National Laboratory - lessons learned.

    SciTech Connect (OSTI)

    Fellhauer, C. R.

    1998-03-23T23:59:59.000Z

    This paper focuses on the lessons learned during the decontamination and decommissioning (D and D) of two reactors at Argonne National Laboratory-East (ANL-E). The Experimental Boiling Water Reactor (EBWR) was a 100 MW(t), 5 MSV(e) proof-of-concept facility. The Janus Reactor was a 200 kW(t) reactor located at the Biological Irradiation Facility and was used to study the effects of neutron radiation on animals.

  4. Recent results and challenges in development of metallic Hall sensors for fusion reactors

    SciTech Connect (OSTI)

    ?uran, Ivan; Mušálek, Radek; Kova?ík, Karel [Institute of Plasma Physics AS CR, Za Slovankou 3, 182 00 Praha 8 (Czech Republic); Sentkerestiová, Jana [Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, B?ehová 7, 115 19 Praha 1 (Czech Republic); Kohout, Michal [Institute of Physics AS CR, Na Slovance 1999/2, 182 21 Praha 8 (Czech Republic); Viererbl, Ladislav [Research Centre Rez, Hlavní 130, 250 68 Husinec-?ež (Czech Republic)

    2014-08-21T23:59:59.000Z

    Reliable and precise diagnostic of local magnetic field is crucial for successful operation of future thermonuclear fusion reactors based on magnetic confinement. Magnetic sensors at these devices will experience an extremely demanding operational environment with large radiation and thermal loads in combination with required long term, reliable, and service-free performance. Neither present day commercial nor laboratory measurement systems comply with these requirements. Metallic Hall sensors based on e.g. copper or bismuth could potentially satisfy these needs. We present the technology for manufacturing of such sensors and some initial results on characterization of their properties.

  5. Reference worldwide model for antineutrinos from reactors

    E-Print Network [OSTI]

    Marica Baldoncini; Ivan Callegari; Giovanni Fiorentini; Fabio Mantovani; Barbara Ricci; Virginia Strati; Gerti Xhixha

    2015-02-16T23:59:59.000Z

    Antineutrinos produced at nuclear reactors constitute a severe source of background for the detection of geoneutrinos, which bring to the Earth's surface information about natural radioactivity in the whole planet. In this framework we provide a reference worldwide model for antineutrinos from reactors, in view of reactors operational records yearly published by the International Atomic Energy Agency (IAEA). We evaluate the expected signal from commercial reactors for ongoing (KamLAND and Borexino), planned (SNO+) and proposed (Juno, RENO-50, LENA and Hanohano) experimental sites. Uncertainties related to reactor antineutrino production, propagation and detection processes are estimated using a Monte Carlo based approach, which provides an overall site dependent uncertainty on the signal in the geoneutrino energy window on the order of 3%. We also implement the off-equilibrium correction to the reference reactor spectra associated with the long-lived isotopes and we estimate a 2.4% increase of the unoscillated event rate in the geoneutrino energy window due to the storage of spent nuclear fuels in the cooling pools. We predict that the research reactors contribute to less than 0.2% to the commercial reactor signal in the investigated 14 sites. We perform a multitemporal analysis of the expected reactor signal over a time lapse of 10 years using reactor operational records collected in a comprehensive database published at www.fe.infn.it/antineutrino.

  6. Charged-Particle Thermonuclear Reaction Rates: I. Monte Carlo Method and Statistical Distributions

    E-Print Network [OSTI]

    Richard Longland; Christian Iliadis; Art Champagne; Joe Newton; Claudio Ugalde; Alain Coc; Ryan Fitzgerald

    2010-04-23T23:59:59.000Z

    A method based on Monte Carlo techniques is presented for evaluating thermonuclear reaction rates. We begin by reviewing commonly applied procedures and point out that reaction rates that have been reported up to now in the literature have no rigorous statistical meaning. Subsequently, we associate each nuclear physics quantity entering in the calculation of reaction rates with a specific probability density function, including Gaussian, lognormal and chi-squared distributions. Based on these probability density functions the total reaction rate is randomly sampled many times until the required statistical precision is achieved. This procedure results in a median (Monte Carlo) rate which agrees under certain conditions with the commonly reported recommended "classical" rate. In addition, we present at each temperature a low rate and a high rate, corresponding to the 0.16 and 0.84 quantiles of the cumulative reaction rate distribution. These quantities are in general different from the statistically meaningless "minimum" (or "lower limit") and "maximum" (or "upper limit") reaction rates which are commonly reported. Furthermore, we approximate the output reaction rate probability density function by a lognormal distribution and present, at each temperature, the lognormal parameters miu and sigma. The values of these quantities will be crucial for future Monte Carlo nucleosynthesis studies. Our new reaction rates, appropriate for bare nuclei in the laboratory, are tabulated in the second paper of this series (Paper II). The nuclear physics input used to derive our reaction rates is presented in the third paper of this series (Paper III). In the fourth paper of this series (Paper IV) we compare our new reaction rates to previous results.

  7. Department of Earth and Mineral Engineering Spring 2011 Oxidative Coupling of Methane Reactor

    E-Print Network [OSTI]

    Demirel, Melik C.

    Reactor Overview The sponsor has tasked our team with the design, construction and testing of an experimental reactor designed to couple methane to ethane and dehydrogenate ethane to ethylene. The reactor and build the reactor and perform methane conversion testing to provide proof of concept for the OCM

  8. Structure of processes in flow reactor and closed reactor: Flow reactor

    E-Print Network [OSTI]

    Greifswald, Ernst-Moritz-Arndt-Universität

    Structure of processes in flow reactor and closed reactor: Flow reactor Closed reactor Active Zone -- chemical quasi- equilibria, similarity principles and macroscopic kinetics", in: Lectures on Plasma Physics

  9. THE FERMI-GBM X-RAY BURST MONITOR: THERMONUCLEAR BURSTS FROM 4U 0614+09

    SciTech Connect (OSTI)

    Linares, M.; Chakrabarty, D. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Connaughton, V.; Bhat, P. N.; Briggs, M. S.; Preece, R. [CSPAR and Physics Department, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Jenke, P.; Kouveliotou, C.; Wilson-Hodge, C. A. [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Van der Horst, A. J. [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, NL-1090-GE Amsterdam (Netherlands); Camero-Arranz, A.; Finger, M.; Paciesas, W. S. [Universities Space Research Association, Huntsville, AL 35805 (United States); Beklen, E. [Physics Department, Suleyman Demirel University, 32260 Isparta (Turkey); Von Kienlin, A. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany)

    2012-12-01T23:59:59.000Z

    Thermonuclear bursts from slowly accreting neutron stars (NSs) have proven difficult to detect, yet they are potential probes of the thermal properties of the NS interior. During the first year of a systematic all-sky search for X-ray bursts using the Gamma-ray Burst Monitor aboard the Fermi Gamma-ray Space Telescope we have detected 15 thermonuclear bursts from the NS low-mass X-ray binary 4U 0614+09 when it was accreting at nearly 1% of the Eddington limit. We measured an average burst recurrence time of 12 {+-} 3 days (68% confidence interval) between 2010 March and 2011 March, classified all bursts as normal duration bursts and placed a lower limit on the recurrence time of long/intermediate bursts of 62 days (95% confidence level). We discuss how observations of thermonuclear bursts in the hard X-ray band compare to pointed soft X-ray observations and quantify such bandpass effects on measurements of burst radiated energy and duration. We put our results for 4U 0614+09 in the context of other bursters and briefly discuss the constraints on ignition models. Interestingly, we find that the burst energies in 4U 0614+09 are on average between those of normal duration bursts and those measured in long/intermediate bursts. Such a continuous distribution in burst energy provides a new observational link between normal and long/intermediate bursts. We suggest that the apparent bimodal distribution that defined normal and long/intermediate duration bursts during the last decade could be due to an observational bias toward detecting only the longest and most energetic bursts from slowly accreting NSs.

  10. Hybrid adsorptive membrane reactor

    DOE Patents [OSTI]

    Tsotsis, Theodore T. (Huntington Beach, CA); Sahimi, Muhammad (Altadena, CA); Fayyaz-Najafi, Babak (Richmond, CA); Harale, Aadesh (Los Angeles, CA); Park, Byoung-Gi (Yeosu, KR); Liu, Paul K. T. (Lafayette Hill, PA)

    2011-03-01T23:59:59.000Z

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  11. Nuclear reactor engineering

    SciTech Connect (OSTI)

    Glasstone, S.; Sesonske, A.

    1982-07-01T23:59:59.000Z

    A book is reviewed which emphasizes topics directly related to the light water reactor power plant and the fast reactor power system. Current real-world problems are addressed throughout the text, and a chapter on safety includes much of the postThree Mile Island impact on operating systems. Topics covered include Doppler broadening, neutron resonances, multigroup diffusion theory, reactor kinetics, reactor control, energy removal, nonfuel materials, reactor fuel, radiation protection, environmental effects, and reactor safety.

  12. The Effects of Variations in Nuclear Interactions on Nucleosynthesis in Thermonuclear Supernovae

    E-Print Network [OSTI]

    Anuj Parikh; Jordi Jose; Ivo R. Seitenzahl; Friedrich K. Roepke

    2013-06-25T23:59:59.000Z

    The impact of nuclear physics uncertainties on nucleosynthesis in thermonuclear supernovae has not been fully explored using comprehensive and systematic studies with multiple models. To better constrain predictions of yields from these phenomena, we have performed a sensitivity study by post-processing thermodynamic histories from two different hydrodynamic, Chandrasekhar-mass explosion models. We have individually varied all input reaction and, for the first time, weak interaction rates by a factor of ten and compared the yields in each case to yields using standard rates. Of the 2305 nuclear reactions in our network, we find that the rates of only 53 reactions affect the yield of any species with an abundance of at least 10^-8 M_sun by at least a factor of two, in either model. The rates of the 12C(a,g), 12C+12C, 20Ne(a,p), 20Ne(a,g) and 30Si(p,g) reactions are among those that modify the most yields when varied by a factor of ten. From the individual variation of 658 weak interaction rates in our network by a factor of ten, only the stellar 28Si(b+)28Al, 32S(b+)32P and 36Ar(b+)36Cl rates significantly affect the yields of species in a model. Additional tests reveal that reaction rate changes over temperatures T > 1.5 GK have the greatest impact, and that ratios of radionuclides that may be used as explosion diagnostics change by a factor of less than two from the variation of individual rates by a factor of 10. Nucleosynthesis in the two adopted models is relatively robust to variations in individual nuclear reaction and weak interaction rates. Laboratory measurements of a limited number of reactions would help to further constrain predictions. As well, we confirm the need for a consistent treatment for relevant stellar weak interaction rates since simultaneous variation of these rates (as opposed to individual variation) has a significant effect on yields in our models.

  13. Parametic Study of the current limit within a single driver-scale transport beam line of an induction Linac for Heavy Ion Fusion

    E-Print Network [OSTI]

    Prost, Lionel Robert

    2007-01-01T23:59:59.000Z

    for a Power Producing Thermonuclear Reactor, in Proceedingsorder for significant thermonuclear energy production, thethe approach to controlled thermonuclear fusion which uses

  14. BURN CONTROL IN FUSION REACTORS VIA NONLINEAR STABILIZATION TECHNIQUES

    E-Print Network [OSTI]

    Krstic, Miroslav

    of low temperature and high density where the thermonuclear reaction is inherently thermally unstable. Figure 1a shows that for low temperatures the rate of thermonuclear reaction for a D-T mixture in stabilization of the thermonuclear reaction can be obtained. Neverthe- less, this approach is often insufficient

  15. On the Frequency Evolution of X-ray Brightness Oscillations During Thermonuclear X-ray Bursts: Evidence for Coherent Oscillations

    E-Print Network [OSTI]

    Tod E. Strohmayer; Craig B. Markwardt

    1999-03-03T23:59:59.000Z

    We investigate the time dependence of the frequency of X-ray brightness oscillations during thermonuclear bursts from several neutron star low mass X-ray binaries. We find that the oscillation frequencies in the cooling tails of X-ray bursts from 4U 1702-429 and 4U 1728-34 are well described by an exponential "chirp" model. With this model we demonstrate that the pulse trains in the cooling tails of many bursts are highly phase coherent, having oscillation quality factors as high as Q ~ 4000. We use this model of the frequency evolution to search sensitively for significant power at the harmonics and first sub-harmonic of the 330 and 363 Hz signals in bursts from 4U 1702-429 and 4U 1728-34, respectively, but find not evidence for significant power at any harmonic or the sub-harmonic. We argue that the high coherence favors stellar rotation as the source of the oscillations. We briefly discuss the frequency evolution in terms of rotational motion of an angular momentum conserving thermonuclear shell. we discuss how the limits on harmonic content can be used to infer properties of the neutron star.

  16. JOURNAL DE PHYSIQUE Colloque C1, supplkment au no2, Tome 40,fkvr~er1979, page C1-73 ATOMIC, IONIC AND MOLECULAR DATA IN THERMO-NUCLEAR FUSION RESEARCH

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    AND MOLECULAR DATA IN THERMO-NUCLEAR FUSION RESEARCH H.W. Drawin Association EURATOM-CEA DQpartement de Physique section deals with molecular data which are of interest in thermo-nuclear fusion research. 1. INTRODUCTION In order to achieve controlled thermo- nuclear fusion of deuterium and tritium one needs both high

  17. Comparison of the recently proposed super-Marx generator approach to thermonuclear ignition with the deuterium-tritium laser fusion-fission hybrid concept by the Lawrence Livermore National Laboratory

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Winterberg, F.

    2009-10-29T23:59:59.000Z

    The recently proposed super-Marx generator pure deuterium microdetonation ignition concept is compared to the Lawrence Livermore National Ignition Facility (NIF) Laser deuterium-tritium fusion-fission hybrid concept (LIFE). In a super-Marx generator, a large number of ordinary Marx generators charge up a much larger second stage ultrahigh voltage Marx generator from which for the ignition of a pure deuterium microexplosion an intense GeV ion beam can be extracted. Typical examples of the LIFE concept are a fusion gain of 30 and a fission gain of 10, making up a total gain of 300, with about ten times more energy released into fission as compared to fusion. This means the substantial release of fission products, as in fissionless pure fission reactors. In the super-Marx approach for the ignition of pure deuterium microdetonation, a gain of the same magnitude can, in theory, be reached. If feasible, the super-Marx generator deuterium ignition approach would make lasers obsolete as a means for the ignition of thermonuclear microexplosions.

  18. Comparison of the recently proposed super-Marx generator approach to thermonuclear ignition with the deuterium-tritium laser fusion-fission hybrid concept by the Lawrence Livermore National Laboratory

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Winterberg, F.

    2009-01-01T23:59:59.000Z

    The recently proposed super-Marx generator pure deuterium microdetonation ignition concept is compared to the Lawrence Livermore National Ignition Facility (NIF) Laser deuterium-tritium fusion-fission hybrid concept (LIFE). In a super-Marx generator, a large number of ordinary Marx generators charge up a much larger second stage ultrahigh voltage Marx generator from which for the ignition of a pure deuterium microexplosion an intense GeV ion beam can be extracted. Typical examples of the LIFE concept are a fusion gain of 30 and a fission gain of 10, making up a total gain of 300, with about ten times more energy released into fissionmore »as compared to fusion. This means the substantial release of fission products, as in fissionless pure fission reactors. In the super-Marx approach for the ignition of pure deuterium microdetonation, a gain of the same magnitude can, in theory, be reached. If feasible, the super-Marx generator deuterium ignition approach would make lasers obsolete as a means for the ignition of thermonuclear microexplosions.« less

  19. SRS Small Modular Reactors

    SciTech Connect (OSTI)

    None

    2012-04-27T23:59:59.000Z

    The small modular reactor program at the Savannah River Site and the Savannah River National Laboratory.

  20. SRS Small Modular Reactors

    ScienceCinema (OSTI)

    None

    2014-05-21T23:59:59.000Z

    The small modular reactor program at the Savannah River Site and the Savannah River National Laboratory.

  1. Reactor safety method

    DOE Patents [OSTI]

    Vachon, Lawrence J. (Clairton, PA)

    1980-03-11T23:59:59.000Z

    This invention relates to safety means for preventing a gas cooled nuclear reactor from attaining criticality prior to start up in the event the reactor core is immersed in hydrogenous liquid. This is accomplished by coating the inside surface of the reactor coolant channels with a neutral absorbing material that will vaporize at the reactor's operating temperature.

  2. Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression

    DOE Patents [OSTI]

    Lasche, G.P.

    1983-09-29T23:59:59.000Z

    The invention is a laser or particle-beam-driven fusion reactor system which takes maximum advantage of both the very short pulsed nature of the energy release of inertial confinement fusion (ICF) and the very small volumes within which the thermonuclear burn takes place. The pulsed nature of ICF permits dynamic direct energy conversion schemes such as magnetohydrodynamic (MHD) generation and magnetic flux compression; the small volumes permit very compact blanket geometries. By fully exploiting these characteristics of ICF, it is possible to design a fusion reactor with exceptionally high power density, high net electric efficiency, and low neutron-induced radioactivity. The invention includes a compact blanket design and method and apparatus for obtaining energy utilizing the compact blanket.

  3. Nuclear reactor

    DOE Patents [OSTI]

    Thomson, Wallace B. (Severna Park, MD)

    2004-03-16T23:59:59.000Z

    A nuclear reactor comprising a cylindrical pressure vessel, an elongated annular core centrally disposed within and spaced from the pressure vessel, and a plurality of ducts disposed longitudinally of the pressure vessel about the periphery thereof, said core comprising an annular active portion, an annular reflector just inside the active portion, and an annular reflector just outside the active a portion, said annular active portion comprising rectangular slab, porous fuel elements radially disposed around the inner reflector and extending the length of the active portion, wedge-shaped, porous moderator elements disposed adjacent one face of each fuel element and extending the length of the fuel element, the fuel and moderator elements being oriented so that the fuel elements face each other and the moderator elements do likewise, adjacent moderator elements being spaced to provide air inlet channels, and adjacent fuel elements being spaced to provide air outlet channels which communicate with the interior of the peripheral ducts, and means for introducing air into the air inlet channels which passes through the porous moderator elements and porous fuel elements to the outlet channel.

  4. Atmospheric Pressure Reactor System | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Atmospheric Pressure Reactor System Atmospheric Pressure Reactor System The atmospheric pressure reactor system is designed for testing the efficiency of various catalysts for the...

  5. On the Effect of Explosive Thermonuclear Burning on the Accreted Envelopes of White Dwarfs in Cataclysmic Variables

    E-Print Network [OSTI]

    Sion, Edward M

    2014-01-01T23:59:59.000Z

    The detection of heavy elements at suprasolar abundances in the atmospheres of some accreting white dwarfs in cataclysmic variables, coupled with the high temperatures needed to produce these elements requires explosive thermonuclear burning. The central temperatures of any formerly more massive secondary stars in CVs undergoing hydrostatic CNO burning are far too low to produce these elements. Evidence is presented that at least some cataclysmic variables contain donor secondaries that have been contaminated by repeated novae ejecta and are transferring this material back to the white dwarf. This scenario does not exclude the channel in which formerly more massive donor stars underwent CNO processing in ystems that underwent thermal timescale mass transfer. Implications for the progenitors of CVs are discussed.

  6. Modeling for Anaerobic Fixed-Bed Biofilm Reactors

    SciTech Connect (OSTI)

    Liu, B. Y. M.; Pfeffer, J. T.

    1989-06-01T23:59:59.000Z

    The specific objectives of this research were: 1. to develop an equilibrium model for chemical aspects of anaerobic reactors; 2. to modify the equilibrium model for non-equilibrium conditions; 3. to incorporate the existing biofilm models into the models above to study the biological and chemical behavior of the fixed-film anaerobic reactors; 4. to experimentally verify the validity of these models; 5. to investigate the biomass-holding ability of difference packing materials for establishing reactor design criteria.

  7. Nuclear reactors built, being built, or planned, 1991

    SciTech Connect (OSTI)

    Simpson, B.

    1992-07-01T23:59:59.000Z

    This document contains unclassified information about facilities built, being built, or planned in the United States for domestic use or export as of December 31, 1991. The book is divided into three major sections: Section 1 consists of a reactor locator map and reactor tables; Section 2 includes nuclear reactors that are operating, being built, or planned; and Section 3 includes reactors that have been shut down permanently or dismantled. Sections 2 and 3 contain the following classification of reactors: Civilian, Production, Military, Export, and Critical Assembly. Export reactor refers to a reactor for which the principal nuclear contractor is an American company -- working either independently or in cooperation with a foreign company (Part 4, in each section). Critical assembly refers to an assembly of fuel and assembly of fuel and moderator that requires an external source of neutrons to initiate and maintain fission. A critical assembly is used for experimental measurements (Part 5).

  8. Deadlock in ITER talks must end Tatsuo Nakajima Yomiuri Shimbun Staff Writer

    E-Print Network [OSTI]

    Japan and the European Union over where to construct the International Thermonuclear Experimental flights home, leaving before those in attendance were able to schedule the next meeting. A thermonuclear fusion, which is more efficient than nuclear fission reactors. In what will be the world's first

  9. Two days of negotiations in

    E-Print Network [OSTI]

    France or Japan would host the revolutionary International Thermonuclear Experimental Reactor (ITER to secure an agreement on whether France or Japan would host the revolutionary International Thermonuclear, deputy director of Japan's Office of Fusion Energy, told AFP. "What we have proposed is that the host

  10. ---Home Yahoo! Help My Yahoo! http://asia.news.yahoo.com/041111/kyodo/d869foe00.html

    E-Print Network [OSTI]

    Thermonuclear Experimental Reactor to Aomori Prefecture. "The Japanese business community should be united with the European Union, the United States, Russia, China and South Korea in the thermonuclear project to create the world's first sustained nuclear fusion reaction, similar to the energy- producing process that takes

  11. ITER site contest counts down Junichi Miura

    E-Print Network [OSTI]

    Thermonuclear Experimental Reactor (ITER), an international project to use nuclear fusion energy for electric on a site for the project. The ITER project envisions using thermonuclear fusion to generate huge amounts heavy hydrogen and tritium used for fuel in the fusion reaction are heated in a vacuum receptacle at 100

  12. POTENTIAL BENCHMARKS FOR ACTINIDE PRODUCTION IN HANFORD REACTORS

    SciTech Connect (OSTI)

    PUIGH RJ; TOFFER H

    2011-10-19T23:59:59.000Z

    A significant experimental program was conducted in the early Hanford reactors to understand the reactor production of actinides. These experiments were conducted with sufficient rigor, in some cases, to provide useful information that can be utilized today in development of benchmark experiments that may be used for the validation of present computer codes for the production of these actinides in low enriched uranium fuel.

  13. Reactor materials study of EBR-II and BN350

    E-Print Network [OSTI]

    Yilmaz, Fatma

    2002-01-01T23:59:59.000Z

    The objective of this research is to go through the technical review of how the body of information relating to the in-reactor behavior of structural materials of Experimental Breeder Reactor-II (EBR-II) and BN350 are associated. Such an effort...

  14. Predicting Reactor Antineutrino Emissions Using New Precision Beta Spectroscopy

    E-Print Network [OSTI]

    D. Asner; K. A. Burns; B. Greenfield; M. S. Kos; J. L. Orrell; M. Schram; B. A. VanDevender; D. Wootan

    2013-04-15T23:59:59.000Z

    A conceptual experimental method for providing a new measurement of the underlying beta decay spectra from fission products is presented. The goal is to provide additional information related to the prediction of the antineutrino emission spectra from fission reactors and assist evaluation of the reactor neutrino anomaly.

  15. Development of an experiment to study the effects of transverse stress on the critical current of a niobium-tin superconducting cable

    E-Print Network [OSTI]

    Chiesa, Luisa

    2006-01-01T23:59:59.000Z

    Superconducting magnets will play a central role for the success of the International Thermonuclear Experimental Reactor (ITER). ITER is a current driven plasma experiment that could set a milestone towards the demonstration ...

  16. On 5 February, President George Bush presented his budget request to Congress

    E-Print Network [OSTI]

    Loss, Daniel

    's Relativistic Heavy Ion Collider was set to abandon running in 2007, and cuts in spending on ITER, the International Thermonuclear Experimental Reactor, threatened a loss of staff, expertise and valuable time

  17. PERFORMANCE BOUNDARIES IN Nb3Sn SUPERCONDUCTORS

    E-Print Network [OSTI]

    of Wisconsin-Madison, USA. This work was supported by the European Union through the European Fusion for the International Thermonuclear Experimental Reactor. Part of the task description was to summarize the results

  18. JOURNAL DE PHYSIQUE IV Colloque C8,supplkmentau Journal de Physique I, Volume 3, d6cembre1993

    E-Print Network [OSTI]

    Boyer, Edmond

    -sur-Yvette,France Abstract. SANS was used to investigate the growth of He-bubbles in a martensitic steel developed for fusion tokamak-based reactors, such as NET/ITER (Next European Torus / International Thermonuclear Experimental

  19. Effects of specimen thickness and impurity on the conductivity of alumina under electron irradiation

    E-Print Network [OSTI]

    Howlader, Matiar R

    windows in the International Thermonuclear Experimental Reactor (ITER), where the electrical conductivity believed to be critical issues for the application of a-Al2O3 to insulators in fusion reac- tors. The RIC

  20. ORNL Environmental Monitoring Programs 5-1 5. ORNL Environmental Monitoring Programs

    E-Print Network [OSTI]

    Pennycook, Steve

    future includes hosting the U.S. project office for the International Thermonuclear Experimental Reactor international fusion experiment and the Office of Science-sponsored Bioenergy Science Center. 5.1 Description

  1. Signicance of sample thickness and surface segregation on the electrical conductivity of Wesgo AL995 alumina under ITER

    E-Print Network [OSTI]

    Howlader, Matiar R

    are expected to be used in fusion reactors like international thermonuclear experimental reactor (ITER insulating material in fusion reactors [1] because of its high thermal conductivity [2], high resistance of alumina are to be used in fusion reactors, no studies have ever been done on the thickness dependence

  2. Reactor Sharing Program

    SciTech Connect (OSTI)

    Vernetson, W.G.

    1993-01-01T23:59:59.000Z

    Progress achieved at the University of Florida Training Reactor (UFTR) facility through the US Department of Energy's University Reactor Sharing Program is reported for the period of 1991--1992.

  3. Undergraduate reactor control experiment

    SciTech Connect (OSTI)

    Edwards, R.M.; Power, M.A.; Bryan, M. (Pennsylvania State Univ., University Park (United States))

    1992-01-01T23:59:59.000Z

    A sequence of reactor and related experiments has been a central element of a senior-level laboratory course at Pennsylvania State University (Penn State) for more than 20 yr. A new experiment has been developed where the students program and operate a computer controller that manipulates the speed of a secondary control rod to regulate TRIGA reactor power. Elementary feedback control theory is introduced to explain the experiment, which emphasizes the nonlinear aspect of reactor control where power level changes are equivalent to a change in control loop gain. Digital control of nuclear reactors has become more visible at Penn State with the replacement of the original analog-based TRIGA reactor control console with a modern computer-based digital control console. Several TRIGA reactor dynamics experiments, which comprise half of the three-credit laboratory course, lead to the control experiment finale: (a) digital simulation, (b) control rod calibration, (c) reactor pulsing, (d) reactivity oscillator, and (e) reactor noise.

  4. Attrition reactor system

    DOE Patents [OSTI]

    Scott, Charles D. (Oak Ridge, TN); Davison, Brian H. (Knoxvile, TN)

    1993-01-01T23:59:59.000Z

    A reactor vessel for reacting a solid particulate with a liquid reactant has a centrifugal pump in circulatory flow communication with the reactor vessel for providing particulate attrition, resulting in additional fresh surface where the reaction can occur.

  5. Attrition reactor system

    DOE Patents [OSTI]

    Scott, C.D.; Davison, B.H.

    1993-09-28T23:59:59.000Z

    A reactor vessel for reacting a solid particulate with a liquid reactant has a centrifugal pump in circulatory flow communication with the reactor vessel for providing particulate attrition, resulting in additional fresh surface where the reaction can occur. 2 figures.

  6. Advanced Computational Thermal Fluid Physics (CTFP) and Its Assessment for Light Water Reactors and Supercritical Reactors

    SciTech Connect (OSTI)

    D.M. McEligot; K. G. Condie; G. E. McCreery; H. M. McIlroy; R. J. Pink; L.E. Hochreiter; J.D. Jackson; R.H. Pletcher; B.L. Smith; P. Vukoslavcevic; J.M. Wallace; J.Y. Yoo; J.S. Lee; S.T. Ro; S.O. Park

    2005-10-01T23:59:59.000Z

    Background: The ultimate goal of the study is the improvement of predictive methods for safety analyses and design of Generation IV reactor systems such as supercritical water reactors (SCWR) for higher efficiency, improved performance and operation, design simplification, enhanced safety and reduced waste and cost. The objective of this Korean / US / laboratory / university collaboration of coupled fundamental computational and experimental studies is to develop the supporting knowledge needed for improved predictive techniques for use in the technology development of Generation IV reactor concepts and their passive safety systems. The present study emphasizes SCWR concepts in the Generation IV program.

  7. Ethylbenzene dehydrogenation into styrene: kinetic modeling and reactor simulation

    E-Print Network [OSTI]

    Lee, Won Jae

    2007-04-25T23:59:59.000Z

    and physicochemical criteria. The kinetic model yielded an excellent fit of the experimental data. The intrinsic kinetic parameters were used with the heterogeneous fixed bed reactor model which is explicitly accounting for the diffusional limitations inside...

  8. Experimental Neutrino Physics: Final Report

    SciTech Connect (OSTI)

    Lane, Charles E.; Maricic, Jelena

    2012-09-05T23:59:59.000Z

    Experimental studies of neutrino properties, with particular emphasis on neutrino oscillation, mass and mixing parameters. This research was pursued by means of underground detectors for reactor anti-neutrinos, measuring the flux and energy spectra of the neutrinos. More recent investigations have been aimed and developing detector technologies for a long-baseline neutrino experiment (LBNE) using a neutrino beam from Fermilab.

  9. Advanced Test Reactor Tour

    SciTech Connect (OSTI)

    Miley, Don

    2011-01-01T23:59:59.000Z

    The Advanced Test Reactor at Idaho National Laboratory is the foremost nuclear materials test reactor in the world. This virtual tour describes the reactor, how experiments are conducted, and how spent nuclear fuel is handled and stored. For more information about INL research, visit http://www.facebook.com/idahonationallaboratory.

  10. High solids fermentation reactor

    DOE Patents [OSTI]

    Wyman, Charles E.; Grohmann, Karel; Himmel, Michael E.; Richard, Christopher J.

    1993-03-02T23:59:59.000Z

    A fermentation reactor and method for fermentation of materials having greater than about 10% solids. The reactor includes a rotatable shaft along the central axis, the shaft including rods extending outwardly to mix the materials. The reactor and method are useful for anaerobic digestion of municipal solid wastes to produce methane, for production of commodity chemicals from organic materials, and for microbial fermentation processes.

  11. High solids fermentation reactor

    DOE Patents [OSTI]

    Wyman, Charles E. (Lakewood, CO); Grohmann, Karel (Littleton, CO); Himmel, Michael E. (Littleton, CO); Richard, Christopher J. (Lakewood, CO)

    1993-01-01T23:59:59.000Z

    A fermentation reactor and method for fermentation of materials having greater than about 10% solids. The reactor includes a rotatable shaft along the central axis, the shaft including rods extending outwardly to mix the materials. The reactor and method are useful for anaerobic digestion of municipal solid wastes to produce methane, for production of commodity chemicals from organic materials, and for microbial fermentation processes.

  12. Improved vortex reactor system

    DOE Patents [OSTI]

    Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO)

    1995-01-01T23:59:59.000Z

    An improved vortex reactor system for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor.

  13. Advanced Test Reactor Tour

    ScienceCinema (OSTI)

    Miley, Don

    2013-05-28T23:59:59.000Z

    The Advanced Test Reactor at Idaho National Laboratory is the foremost nuclear materials test reactor in the world. This virtual tour describes the reactor, how experiments are conducted, and how spent nuclear fuel is handled and stored. For more information about INL research, visit http://www.facebook.com/idahonationallaboratory.

  14. Teaching Sodium Fast Reactor Technology and Operation for the Present and Future Generations of SFR Users

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Teaching Sodium Fast Reactor Technology and Operation for the Present and Future Generations of SFR or development of sodium fast reactors and related experimental facilities. The sum of courses provided by CEA on sodium fast reactor design, technology, safety and operation experience, decommissioning aspects

  15. Japanese set to direct `sun-power' nuclear reactor in France September 16, 2005

    E-Print Network [OSTI]

    Japanese set to direct `sun-power' nuclear reactor in France September 16, 2005 Japan has been develop three generations of nuclear reactors and includes six low-capacity experimental reactors and a 17 asked to nominate the chief of an international project to build a multi- billion-dollar nuclear fusion

  16. Experimental Study of Pellet Delivery to the ITER Inner Wall through a Curved Guide Tube at Steady-State Pressure

    SciTech Connect (OSTI)

    Combs, Stephen Kirk [ORNL; Baylor, Larry R [ORNL; Caughman, John B [ORNL; Fehling, Dan T [ORNL; Foust, Charles R [ORNL; Maruyama, S. [ITER International Team, Garching, Germany; McGill, James M [ORNL; Rasmussen, David A [ORNL

    2006-01-01T23:59:59.000Z

    Injection of solid hydrogen pellets from the magnetic high-field side will be the primary technique for depositing fuel particles into the core of International Thermonuclear Experimental Reactor (ITER) burning plasmas. This injection scheme will require the use of a curved guide tube to route the pellets from the acceleration device, under the divertor, and to the inside wall launch location. In an initial series of pellet tests in support of ITER, single 5.3-mm-diam cylindrical D2 pellets were shot through a mock-up of the planned ITER curved guide tube. Those data showed that the pellet speed had to be limited to ?300 m/s for reliable delivery of intact pellets. Also, microwave cavity mass detectors located upstream and downstream of the test tube indicated that ?10% of the pellet mass was lost in the guide tube at 300 m/s. The tube base pressure for that test series was ?10-4 torr. However, for steady-state pellet fueling on ITER, the guide tube will operate at an elevated pressure due to the pellet erosion in the tube. Assuming the present design values for ITER pellet fueling rates/vacuum pumping and a 10% pellet mass loss during flight in the tube, calculations suggest a steadystate operating pressure in the range of 10-20 torr. Thus, experiments to ascertain the pellet integrity and mass loss under these conditions have been carried out. Also, some limited test data were collected at a tube pressure of ?100 torr. No significant detrimental effects have been observed at the higher tube pressures. The new test results are presented and compared to the baseline data previously reported.

  17. The thermonuclear rate for the 19F(a,p)22Ne reaction at stellar temperatures

    E-Print Network [OSTI]

    Claudio Ugalde; Richard Azuma; Aaron Couture; Joachim Görres; Hye-Young Lee; Edward Stech; Elizabeth Strandberg; Wanpeng Tan; Michael Wiescher

    2008-03-04T23:59:59.000Z

    The $^{19}$F($\\alpha$,p)$^{22}$Ne reaction is considered to be one of the main sources of fluorine depletion in AGB and Wolf-Rayet stars. The reaction rate still retains large uncertainties due to the lack of experimental studies available. In this work the yields for both exit channels to the ground state and first excited state of $^{22}$Ne have been measured and several previously unobserved resonances have been found in the energy range E$_{lab}$=792-1993 keV. The level parameters have been determined through a detailed R-matrix analysis of the reaction data and a new reaction rate is provided on the basis of the available experimental information.

  18. Neutron behavior, reactor control, and reactor heat transfer. Volume four

    SciTech Connect (OSTI)

    Not Available

    1986-01-01T23:59:59.000Z

    Volume four covers neutron behavior (neutron absorption, how big are nuclei, neutron slowing down, neutron losses, the self-sustaining reactor), reactor control (what is controlled in a reactor, controlling neutron population, is it easy to control a reactor, range of reactor control, what happens when the fuel burns up, controlling a PWR, controlling a BWR, inherent safety of reactors), and reactor heat transfer (heat generation in a nuclear reactor, how is heat removed from a reactor core, heat transfer rate, heat transfer properties of the reactor coolant).

  19. Reactor vessel support system

    DOE Patents [OSTI]

    Golden, Martin P. (Trafford, PA); Holley, John C. (McKeesport, PA)

    1982-01-01T23:59:59.000Z

    A reactor vessel support system includes a support ring at the reactor top supported through a box ring on a ledge of the reactor containment. The box ring includes an annular space in the center of its cross-section to reduce heat flow and is keyed to the support ledge to transmit seismic forces from the reactor vessel to the containment structure. A coolant channel is provided at the outside circumference of the support ring to supply coolant gas through the keyways to channels between the reactor vessel and support ledge into the containment space.

  20. Reactor water cleanup system

    DOE Patents [OSTI]

    Gluntz, D.M.; Taft, W.E.

    1994-12-20T23:59:59.000Z

    A reactor water cleanup system includes a reactor pressure vessel containing a reactor core submerged in reactor water. First and second parallel cleanup trains are provided for extracting portions of the reactor water from the pressure vessel, cleaning the extracted water, and returning the cleaned water to the pressure vessel. Each of the cleanup trains includes a heat exchanger for cooling the reactor water, and a cleaner for cleaning the cooled reactor water. A return line is disposed between the cleaner and the pressure vessel for channeling the cleaned water thereto in a first mode of operation. A portion of the cooled water is bypassed around the cleaner during a second mode of operation and returned through the pressure vessel for shutdown cooling. 1 figure.

  1. Spinning fluids reactor

    SciTech Connect (OSTI)

    Miller, Jan D; Hupka, Jan; Aranowski, Robert

    2012-11-20T23:59:59.000Z

    A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.

  2. Determining Reactor Neutrino Flux

    E-Print Network [OSTI]

    Jun Cao

    2012-03-08T23:59:59.000Z

    Flux is an important source of uncertainties for a reactor neutrino experiment. It is determined from thermal power measurements, reactor core simulation, and knowledge of neutrino spectra of fuel isotopes. Past reactor neutrino experiments have determined the flux to (2-3)% precision. Precision measurements of mixing angle $\\theta_{13}$ by reactor neutrino experiments in the coming years will use near-far detector configurations. Most uncertainties from reactor will be canceled out. Understanding of the correlation of uncertainties is required for $\\theta_{13}$ experiments. Precise determination of reactor neutrino flux will also improve the sensitivity of the non-proliferation monitoring and future reactor experiments. We will discuss the flux calculation and recent progresses.

  3. Role of research reactors in training of NPP personnel with special focus on training reactor VR-1

    SciTech Connect (OSTI)

    Sklenka, L.; Rataj, J.; Frybort, J.; Huml, O. [Dept. of Nuclear Reactors, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical Univ. in Prague, V Holesovickach 2, Prague 8, 180 00 (Czech Republic)

    2012-07-01T23:59:59.000Z

    Research reactors play an important role in providing key personnel of nuclear power plants a hands-on experience from operation and experiments at nuclear facilities. Training of NPP (Nuclear Power Plant) staff is usually deeply theoretical with an extensive utilisation of simulators and computer visualisation. But a direct sensing of the reactor response to various actions can only improve the personnel awareness of important aspects of reactor operation. Training Reactor VR-1 and its utilization for training of NPP operators and other professionals from Czech Republic and Slovakia is described. Typical experimental exercises and good practices in organization of a training program are demonstrated. (authors)

  4. The longest thermonuclear X-ray burst ever observed? (A BeppoSAX Wide Field Camera observation of 4U 1735-44)

    E-Print Network [OSTI]

    R. Cornelisse; J. Heise; E. Kuulkers; F. Verbunt; J. J. M. in 't Zand

    2000-03-30T23:59:59.000Z

    A long flux enhancement, with an exponential decay time of 86 min, is detected in 4U 1735-44 with the BeppoSAX Wide Field Cameras. We argue that this is a type-I X-ray burst, making it the longest such burst ever observed. Current theories for thermonuclear bursts predict shorter and more frequent bursts for the observed persistent accretion rate.

  5. Dynamic reactor modeling with applications to SPR and ZEDNA.

    SciTech Connect (OSTI)

    Suo-Anttila, Ahti Jorma

    2011-12-01T23:59:59.000Z

    A dynamic reactor model has been developed for pulse-type reactor applications. The model predicts reactor power, axial and radial fuel expansion, prompt and delayed neutron population, and prompt and delayed gamma population. All model predictions are made as a function of time. The model includes the reactivity effect of fuel expansion on a dynamic timescale as a feedback mechanism for reactor power. All inputs to the model are calculated from first principles, either directly by solving systems of equations, or indirectly from Monte Carlo N-Particle Transport Code (MCNP) derived results. The model does not include any empirical parameters that can be adjusted to match experimental data. Comparisons of model predictions to actual Sandia Pulse Reactor SPR-III pulses show very good agreement for a full range of pulse magnitudes. The model is also applied to Z-pinch externally driven neutron assembly (ZEDNA) type reactor designs to model both normal and off-normal ZEDNA operations.

  6. A reference worldwide model for antineutrinos from reactors

    E-Print Network [OSTI]

    Baldoncini, Marica; Fiorentini, Giovanni; Mantovani, Fabio; Ricci, Barbara; Strati, Virginia; Xhixha, Gerti

    2014-01-01T23:59:59.000Z

    Antineutrinos produced at nuclear reactors constitute a severe source of background for the detection of geoneutrinos, which bring to the Earth's surface information about natural radioactivity in the whole planet. In this framework we provide a reference worldwide model for antineutrinos from reactors, in view of reactors operational records yearly published by the International Atomic Energy Agency (IAEA). We evaluate the expected signal from commercial reactors for ongoing (KamLAND and Borexino), planned (SNO+) and proposed (Juno, RENO-50, LENA and Hanohano) experimental sites. Uncertainties related to reactor antineutrino production, propagation and detection processes are estimated using a Monte Carlo based approach, which provides an overall site dependent uncertainty on the signal in the geoneutrino energy window on the order of 3%. We also implement the off-equilibrium correction to the reference reactor spectra associated with the long-lived isotopes and we estimate a 2.4% increase of the unoscillate...

  7. The Long Term Stability of Oscillations During Thermonuclear X-ray Bursts: Constraining the Binary X-ray Mass Function

    E-Print Network [OSTI]

    Tod E. Strohmayer; William Zhang; Jean H. Swank; Iosif Lapidus

    1998-06-18T23:59:59.000Z

    We report on the long term stability of the millisecond oscillations observed with the Rossi X-ray Timing Explorer (RXTE) during thermonuclear X-ray bursts from the low mass X-ray binaries (LMXB) 4U 1728-34 and 4U 1636-53. We show that bursts from 4U 1728-34 spanning more than 1.5 years have observed asymptotic oscillation periods which are within 0.2 microsec. of each other, well within the magnitude which could be produced by the orbital motion of the neutron star in a typical LMXB. This stability implies a timescale to change the oscillation period of > 23,000 years, suggesting a highly stable process such as stellar rotation as the oscillation mechanism. We show that period offsets in three distinct bursts from 4U 1636-53 can be plausibly interpreted as due to orbital motion of the neutron star in this 3.8 hour binary system. We discuss the constraints on the mass function which can in principle be derived using this technique.

  8. Systematic variation in the apparent burning area of thermonuclear bursts and its implication for neutron star radius measurement

    E-Print Network [OSTI]

    Sudip Bhattacharyya; M. Coleman Miller; Duncan K. Galloway

    2009-08-28T23:59:59.000Z

    Precision measurements of neutron star radii can provide a powerful probe of the properties of cold matter beyond nuclear density. Beginning in the late 1970s it was proposed that the radius could be obtained from the apparent or inferred emitting area during the decay portions of thermonuclear (type I) X-ray bursts. However, this apparent area is generally not constant, preventing reliable measurement of the source radius. Here we report for the first time a correlation between the variation of the inferred area and the burst properties, measured in a sample of almost 900 bursts from 43 sources. We found that the rate of change of the inferred area during decay is anticorrelated with the burst decay duration. A Spearman rank correlation test shows that this relation is significant at the <10^{-45} level for our entire sample, and at the 7x10^{-37} level for the 625 bursts without photospheric radius expansion. This anticorrelation is also highly significant for individual sources exhibiting a wide range of burst durations, such as 4U 1636-536 and Aql X-1. We suggest that variations in the colour factor, which relates the colour temperature resulted from the scattering in the neutron star atmosphere to the effective temperature of the burning layer, may explain the correlation. This in turn implies significant variations in the composition of the atmosphere between bursts with long and short durations.

  9. BDDR, a new CEA technological and operating reactor database

    SciTech Connect (OSTI)

    Soldevilla, M.; Salmons, S.; Espinosa, B. [CEA-Saclay, CEA/DEN/DANS/DM2S/SERMA, 91191 Gif-sur-Yvette (France); Clanet, M.; Boudin, X. [CEA-Bruyeres-le-Chatel, 91297 Arpajon (France)

    2013-07-01T23:59:59.000Z

    The new application BDDR (Reactor database) has been developed at CEA in order to manage nuclear reactors technological and operating data. This application is a knowledge management tool which meets several internal needs: -) to facilitate scenario studies for any set of reactors, e.g. non-proliferation assessments; -) to make core physics studies easier, whatever the reactor design (PWR-Pressurized Water Reactor-, BWR-Boiling Water Reactor-, MAGNOX- Magnesium Oxide reactor-, CANDU - CANada Deuterium Uranium-, FBR - Fast Breeder Reactor -, etc.); -) to preserve the technological data of all reactors (past and present, power generating or experimental, naval propulsion,...) in a unique repository. Within the application database are enclosed location data and operating history data as well as a tree-like structure containing numerous technological data. These data address all kinds of reactors features and components. A few neutronics data are also included (neutrons fluxes). The BDDR application is based on open-source technologies and thin client/server architecture. The software architecture has been made flexible enough to allow for any change. (authors)

  10. Unconventional digital reactor control without conventional programming

    SciTech Connect (OSTI)

    Edwards, R.M.; Johns, R.M.; Kenney, S.J. [Pennsylvania State Univ., University Park, PA (United States)

    1995-12-31T23:59:59.000Z

    Recent advances in simulation technology have resulted in the capability to design, test, and implement advanced control algorithms without the need for the labor-intensive effort of writing and debugging of computer programs. This technology has been adopted for a program of experimental development of power reactor control, which is jointly sponsored by the National Science Foundation and the Electric Power Research Institute. The experimental reactor control test bed utilizes the General Atomic Mark III TRIGA reactor at the Penn State Breazeale reactor facility. Control experiments are conducted within the movable experiment technical specifications of the TRIGA. A digital controller with an experimental control algorithm is interfaced to a secondary control rod (SCR). The new technology presented in this paper utilizes a UNIX network-compatible microprocessor-based controller operating under the Wind River Systems VxWorks real-time operating system. The controller interfaces with the Math-works MATLAB/SIMULINK development environment and Real-Time Innovations 8 monitoring software remotely operated on a SPARC workstation.

  11. aries tokamak reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to Particle Source Identification in Tokamaks Physics Websites Summary: controlled thermonuclear fusion for power generation. The proposed approach relies on the design...

  12. aircraft propulsion reactors: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to produce adequate thrust, reduce ... Dicara, Daniel L 2006-01-01 13 Simplest AB-Thermonuclear Space Propulsion and Electric Generator CERN Preprints Summary: The author...

  13. aecl radiochemical slowpoke reactor: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    medicine, in the nondestructive control of fissionable materials, diagnostics of thermonuclear plasma, monit... Lebedev, S G 2005-01-01 16 Gaseous Radiochemical Method for...

  14. Improved vortex reactor system

    DOE Patents [OSTI]

    Diebold, J.P.; Scahill, J.W.

    1995-05-09T23:59:59.000Z

    An improved vortex reactor system is described for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor. 12 figs.

  15. Tokamak reactor first wall

    DOE Patents [OSTI]

    Creedon, R.L.; Levine, H.E.; Wong, C.; Battaglia, J.

    1984-11-20T23:59:59.000Z

    This invention relates to an improved first wall construction for a tokamak fusion reactor vessel, or other vessels subjected to similar pressure and thermal stresses.

  16. Pressurized fluidized bed reactor

    DOE Patents [OSTI]

    Isaksson, Juhani (Karhula, FI)

    1996-01-01T23:59:59.000Z

    A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine.

  17. Pressurized fluidized bed reactor

    DOE Patents [OSTI]

    Isaksson, J.

    1996-03-19T23:59:59.000Z

    A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine. 1 fig.

  18. PLASMA-PHYSICS-21 Heavy ion driven reactor-size double shell inertial fusion targets*

    E-Print Network [OSTI]

    M. C. Serna Moreno; N. A. Tahir; J. J. López Cela; A. R. Piriz; D. H. H. Hoffmann

    Inertial Confinement Fusion (ICF) is considered as an alternative to Magnetic Confinement Fusion to achieve controlled thermonuclear fusion. The main goal is to exploit the energy released from thermonuclear fusion reactions

  19. Reactor safety research programs. Quarterly report Apr-Jun 81

    SciTech Connect (OSTI)

    Edler, S.K.

    1981-09-01T23:59:59.000Z

    This document summarizes the work performed by Pacific Northwest Laboratory (PNL) from April 1 through June 30, 1981, for the Division of Reactor Safety Research within the U.S. Nuclear Regulatory Commission (NRC). Evaluations of nondestructive examination (NDE) techniques and instrumentation are reported; areas of investigation include demonstrating the feasibility of determining the strength of structural graphite, evaluating the feasibility of detecting and analyzing flaw growth in reactor pressure boundary systems, examining NDE reliability and probabilistic fracture mechanics, and assessing the integrity of pressurized water reactor (PWR) steam generator tubes where service-induced degradation has been indicated. Experimental data and analytical models are being provided to aid in decision-making regarding pipe-to-pipe impacts following postulated breaks in high-energy fluid system piping. Core thermal models are being developed to provide better digital codes to compute the behavior of full-scale reactor systems under postulated accident conditions. Fuel assemblies and analytical support are being provided for experimental programs at other facilities. These programs include loss-of-coolant accident (LOCA) simulation tests at the NRU reactor, Chalk River, Canada; fuel rod deformation, severe fuel damage, and postaccident coolability tests for the ESSOR reactor Super Sara Test Program, Ispra, Italy; the instrumented fuel assembly irradiation program at Halden, Norway; and experimental programs at the Power Burst Facility, Idaho National Engineering Laboratory (INEL). These programs will provide data for computer modeling of reactor system and fuel performance during various abnormal operating conditions.

  20. Reactor Safety Research Programs Quarterly Report April- June 1981

    SciTech Connect (OSTI)

    Edler, S. K.

    1981-09-01T23:59:59.000Z

    This document summarizes the work performed by Pacific Northwest laboratory (PNL} from April1 through June 30, 1981, for the Division of Reactor Safety Research within the U.S. Nuclear Regulatory Commission (NRC). Evaluations of nondestructive examination (NDE) techniques and instrumentation are reported; areas of investigation include demonstrating the feasibility of determining the strength of structural graphite, evaluating the feasibility of detecting and analyzing flaw growth in reactor pressure boundary systems, examining NDE reliability and probabilistic fracture mechanics, and assessing the integrity of pressurized water reactor (PWR) steam generator tubes where service-induced degradation has been indicated. Experimental data and analytical models are being provided to aid in decision-making regarding pipe-to-pipe impacts following postulated breaks in high-energy fluid system piping. Core thermal models are being developed to provide better digital codes to compute the behavior of full-scale reactor systems under postulated accident conditions. Fuel assemblies and analytical support are being provided for experimental programs at other facilities. These programs include loss-of-coolant accident (LOCA) simulation tests at the NRU reactor, Chalk River, Canada; fuel rod deformation, severe fuel damage, and postaccident coolability tests for the ESSOR reactor Super Sara Test Program, lspra, Italy; the instrumented fuel assembly irradiation program at Halden, Norway; and experimental programs at the Power Burst Facility, Idaho National Engineering Laboratory {INEL). These programs will provide data for computer modeling of reactor system and fuel performance during various abnormal operating conditions.

  1. Brookhaven Graphite Research Reactor Workshop

    Broader source: Energy.gov [DOE]

    The Brookhaven Graphite Research Reactor (BGRR) was the first reactor built in the U.S. for peacetime atomic research following World War II.  Construction began in 1947 and the reactor started...

  2. Turing patterns in an open reactor

    SciTech Connect (OSTI)

    Vastano, J.A.; Pearson, J.E.; Horsthemke, W.; Swinney, H.L.

    1988-05-15T23:59:59.000Z

    Steady spatial chemical patterns have been found in model reaction--diffusion systems but have not yet been observed in any laboratory experiments. The reasons for this are discussed and the need for open reactors is stressed. A model open reactor is investigated in order to guide the experimental search for steady patterns. Specifically, Turing bifurcations in this reactor are studied for a simple autocatalytic chemistry (the Gray--Scott model) in order to determine the effects of varying diffusion coefficients, chemical time scales, and residence time. A description of all the steady-state bifurcations from an initially homogeneous state is obtained. The Liapunov--Schmidt reduction is used to determine the stability of the bifurcating solutions and a steady-state continuation technique is used to follow stable and unstable branches of bifurcating solutions.

  3. Irradiation behavior of metallic fast reactor fuels

    SciTech Connect (OSTI)

    Pahl, R.G.; Porter, D.L.; Crawford, D.C.; Walters, L.C.

    1991-01-01T23:59:59.000Z

    Metallic fuels were the first fuels chosen for liquid metal cooled fast reactors (LMR's). In the late 1960's world-wide interest turned toward ceramic LMR fuels before the full potential of metallic fuel was realized. However, during the 1970's the performance limitations of metallic fuel were resolved in order to achieve a high plant factor at the Argonne National Laboratory's Experimental Breeder Reactor II. The 1980's spawned renewed interest in metallic fuel when the Integral Fast Reactor (IFR) concept emerged at Argonne National Laboratory. A fuel performance demonstration program was put into place to obtain the data needed for the eventual licensing of metallic fuel. This paper will summarize the results of the irradiation program carried out since 1985.

  4. REACTOR OPERATIONS AND CONTROL

    E-Print Network [OSTI]

    Pázsit, Imre

    REACTOR OPERATIONS AND CONTROL KEYWORDS: core calculations, neural networks, control rod elevation of a control rod, or a group of control rods, is an important parameter from the viewpoint of reactor control DETERMINATION OF PWR CONTROL ROD POSITION BY CORE PHYSICS AND NEURAL NETWORK METHODS NINOS S. GARIS* and IMRE

  5. Charged-Particle Thermonuclear Reaction Rates: II. Tables and Graphs of Reaction Rates and Probability Density Functions

    E-Print Network [OSTI]

    Christian Iliadis; Richard Longland; Art Champagne; Alain Coc; Ryan Fitzgerald

    2010-04-23T23:59:59.000Z

    Numerical values of charged-particle thermonuclear reaction rates for nuclei in the A=14 to 40 region are tabulated. The results are obtained using a method, based on Monte Carlo techniques, that has been described in the preceding paper of this series (Paper I). We present a low rate, median rate and high rate which correspond to the 0.16, 0.50 and 0.84 quantiles, respectively, of the cumulative reaction rate distribution. The meaning of these quantities is in general different from the commonly reported, but statistically meaningless expressions, "lower limit", "nominal value" and "upper limit" of the total reaction rate. In addition, we approximate the Monte Carlo probability density function of the total reaction rate by a lognormal distribution and tabulate the lognormal parameters {\\mu} and {\\sigma} at each temperature. We also provide a quantitative measure (Anderson-Darling test statistic) for the reliability of the lognormal approximation. The user can implement the approximate lognormal reaction rate probability density functions directly in a stellar model code for studies of stellar energy generation and nucleosynthesis. For each reaction, the Monte Carlo reaction rate probability density functions, together with their lognormal approximations, are displayed graphically for selected temperatures in order to provide a visual impression. Our new reaction rates are appropriate for bare nuclei in the laboratory. The nuclear physics input used to derive our reaction rates is presented in the subsequent paper of this series (Paper III). In the fourth paper of this series (Paper IV) we compare our new reaction rates to previous results.

  6. Investigation of thermonuclear $^{18}$Ne($?$,$p$)$^{21}$Na rate via resonant elastic scattering of $^{21}$Na+$p$

    E-Print Network [OSTI]

    L. Y. Zhang; J. J. He; A. Parikh; S. W. Xu; H. Yamaguchi; D. Kahl; S. Kubono; P. Mohr; J. Hu; P. Ma; S. Z. Chen; Y. Wakabayashi; H. W. Wang; W. D. Tian; R. F. Chen; B. Guo; T. Hashimoto; Y. Togano; S. Hayakawa; T. Teranishi; N. Iwasa; T. Yamada; T. Komatsubara; Y. H. Zhang; X. H. Zhou

    2014-03-19T23:59:59.000Z

    The $^{18}$Ne($\\alpha$,$p$)$^{21}$Na reaction is thought to be one of the key breakout reactions from the hot CNO cycles to the rp-process in type I x-ray bursts. In this work, the resonant properties of the compound nucleus $^{22}$Mg have been investigated by measuring the resonant elastic scattering of $^{21}$Na+$p$. An 89 MeV $^{21}$Na radioactive beam delivered from the CNS Radioactive Ion Beam Separator bombarded an 8.8 mg/cm$^2$ thick polyethylene (CH$_{2}$)$_{n}$ target. The $^{21}$Na beam intensity was about 2$\\times$10$^{5}$ pps, with a purity of about 70% on target. The recoiled protons were measured at the center-of-mass scattering angles of $\\theta_{c.m.}$$\\approx$175.2${^\\circ}$, 152.2${^\\circ}$, and 150.5${^\\circ}$ by three sets of $\\Delta E$-$E$ telescopes, respectively. The excitation function was obtained with the thick-target method over energies $E_x$($^{22}$Mg)=5.5--9.2 MeV. In total, 23 states above the proton-threshold in $^{22}$Mg were observed, and their resonant parameters were determined via an $R$-matrix analysis of the excitation functions. We have made several new $J^{\\pi}$ assignments and confirmed some tentative assignments made in previous work. The thermonuclear $^{18}$Ne($\\alpha$,$p$)$^{21}$Na rate has been recalculated based on our recommended spin-parity assignments. The astrophysical impact of our new rate has been investigated through one-zone postprocessing x-ray burst calculations. We find that the $^{18}$Ne($\\alpha$,$p$)$^{21}$Na rate significantly affects the peak nuclear energy generation rate, reaction fluxes, as well as the onset temperature of this breakout reaction in these astrophysical phenomena.

  7. Reed Reactor Facility. Final report

    SciTech Connect (OSTI)

    Frantz, S.G.

    1994-12-31T23:59:59.000Z

    This report discusses the operation and maintenance of the Reed Reactor Facility. The Reed reactor is mostly used for education and train purposes.

  8. Reactor & Nuclear Systems Publications | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Science Home | Science & Discovery | Nuclear Science | Publications and Reports | Reactor and Nuclear Systems Publications SHARE Reactor and Nuclear Systems Publications The...

  9. ---Home Yahoo! Help My Yahoo! http://asia.news.yahoo.com/041102/kyodo/d863kr500.html

    E-Print Network [OSTI]

    November 2, 17:04 PM Japan, EU, others to discuss nuclear fusion reactor next week Japan, the European where they will build the world's first prototype nuclear fusion reactor, Japan's science ministry said are together working on the International Thermonuclear Experimental Reactor project will meet next Tuesday

  10. Determining Reactor Flux from Xenon-136 and Cesium-135 in Spent Fuel

    E-Print Network [OSTI]

    A. C. Hayes; Gerard Jungman

    2012-05-30T23:59:59.000Z

    The ability to infer the reactor flux from spent fuel or seized fissile material would enhance the tools of nuclear forensics and nuclear nonproliferation significantly. We show that reactor flux can be inferred from the ratios of xenon-136 to xenon-134 and cesium-135 to cesium-137. If the average flux of a reactor is known, the flux inferred from measurements of spent fuel could help determine whether that spent fuel was loaded as a blanket or close to the mid-plane of the reactor. The cesium ratio also provides information on reactor shutdowns during the irradiation of fuel, which could prove valuable for identifying the reactor in question through comparisons with satellite reactor heat monitoring data. We derive analytic expressions for these correlations and compare them to experimental data and to detailed reactor burn simulations. The enrichment of the original uranium fuel affects the correlations by up to 3 percent, but only at high flux.

  11. Experimental Highlights

    E-Print Network [OSTI]

    Dainton, John

    2010-01-01T23:59:59.000Z

    Highlights at the 13th International Conference on Elastic & Diffractive Scattering (EDS09) of the presentations of new experimental results and developments are presented and discussed.

  12. Nuclear reactor control column

    SciTech Connect (OSTI)

    Bachovchin, D.M.

    1982-08-10T23:59:59.000Z

    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest crosssectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor.

  13. Nuclear reactor control column

    DOE Patents [OSTI]

    Bachovchin, Dennis M. (Plum Borough, PA)

    1982-01-01T23:59:59.000Z

    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest cross-sectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor.

  14. Lithium Ceramic Blankets for Russian Fusion Reactors and Influence of Breeding Operation Mode on Parameters of Reactor Tritium Systems

    SciTech Connect (OSTI)

    Kapyshev, Victor K.; Chernetsov, Mikhail Yu.; Zhevotov, Sergej I.; Kersnovskij, Alexandr Yu.; Kolbasov, Boris N.; Kovalenko, Victor G.; Paltusov, Nikolaj P.; Sernyaev, Georgeij A.; Sterebkov, Juri S.; Zyryanov, Alexej P. [A.A. Bochvar Institute of Inorganic Materials (Russian Federation)

    2005-07-15T23:59:59.000Z

    Russian controlled fusion program supposes development of a DEMO reactor design and participation in ITER Project. A solid breeder blanket of DEMO contains a ceramic lithium orthosilicate breeder and a beryllium multiplier. Test modules of the blanket are developed within the scope of ITER activities. Experimental models of module tritium breeding zones (TBZ), materials and fabrication technology of the TBZ, tritium reactor systems to analyse and process gas released from lithium ceramics are being developed. Two models of tritium breeding and neutron multiplying elements of the TBZ have been designed, manufactured and tested in IVV-2M nuclear reactor. Initial results of the in-pile experiments and outcome of lithium ceramics irradiation in a water-graphite nuclear reactor are considered to be a data base for development of the test modules and initial requirements for DEMO tritium system design. Influence of the tritium release parameters and hydrogen concentration in a purge gas on parameters of reactor system are discussed.

  15. Fast Breeder Reactor studies

    SciTech Connect (OSTI)

    Till, C.E.; Chang, Y.I.; Kittel, J.H.; Fauske, H.K.; Lineberry, M.J.; Stevenson, M.G.; Amundson, P.I.; Dance, K.D.

    1980-07-01T23:59:59.000Z

    This report is a compilation of Fast Breeder Reactor (FBR) resource documents prepared to provide the technical basis for the US contribution to the International Nuclear Fuel Cycle Evaluation. The eight separate parts deal with the alternative fast breeder reactor fuel cycles in terms of energy demand, resource base, technical potential and current status, safety, proliferation resistance, deployment, and nuclear safeguards. An Annex compares the cost of decommissioning light-water and fast breeder reactors. Separate abstracts are included for each of the parts.

  16. Spherical torus fusion reactor

    DOE Patents [OSTI]

    Martin Peng, Y.K.M.

    1985-10-03T23:59:59.000Z

    The object of this invention is to provide a compact torus fusion reactor with dramatic simplification of plasma confinement design. Another object of this invention is to provide a compact torus fusion reactor with low magnetic field and small aspect ratio stable plasma confinement. In accordance with the principles of this invention there is provided a compact toroidal-type plasma confinement fusion reactor in which only the indispensable components inboard of a tokamak type of plasma confinement region, mainly a current conducting medium which carries electrical current for producing a toroidal magnet confinement field about the toroidal plasma region, are retained.

  17. Nuclear reactor reflector

    DOE Patents [OSTI]

    Hopkins, Ronald J. (Pensacola, FL); Land, John T. (Pensacola, FL); Misvel, Michael C. (Pensacola, FL)

    1994-01-01T23:59:59.000Z

    A nuclear reactor reflector is disclosed that comprises a stack of reflector blocks with vertical water flow passages to cool the reflector. The interface between blocks is opposite support points for reactor fuel rods. Water flows between the reflector and the reactor barrel from passages in a bottom block. The top block contains a flange to limit this flow and the flange has a slot to receive an alignment pin that is welded to the barrel. The pin is held in the slot by two removable shims. Alignment bars extend the length of the stack in slots machined in each block when the stack is assembled.

  18. Nuclear reactor reflector

    DOE Patents [OSTI]

    Hopkins, R.J.; Land, J.T.; Misvel, M.C.

    1994-06-07T23:59:59.000Z

    A nuclear reactor reflector is disclosed that comprises a stack of reflector blocks with vertical water flow passages to cool the reflector. The interface between blocks is opposite support points for reactor fuel rods. Water flows between the reflector and the reactor barrel from passages in a bottom block. The top block contains a flange to limit this flow and the flange has a slot to receive an alignment pin that is welded to the barrel. The pin is held in the slot by two removable shims. Alignment bars extend the length of the stack in slots machined in each block when the stack is assembled. 12 figs.

  19. Microfluidic electrochemical reactors

    DOE Patents [OSTI]

    Nuzzo, Ralph G. (Champaign, IL); Mitrovski, Svetlana M. (Urbana, IL)

    2011-03-22T23:59:59.000Z

    A microfluidic electrochemical reactor includes an electrode and one or more microfluidic channels on the electrode, where the microfluidic channels are covered with a membrane containing a gas permeable polymer. The distance between the electrode and the membrane is less than 500 micrometers. The microfluidic electrochemical reactor can provide for increased reaction rates in electrochemical reactions using a gaseous reactant, as compared to conventional electrochemical cells. Microfluidic electrochemical reactors can be incorporated into devices for applications such as fuel cells, electrochemical analysis, microfluidic actuation, pH gradient formation.

  20. Light-water reactor safety analysis codes

    SciTech Connect (OSTI)

    Jackson, J.F.; Ransom, V.H.; Ybarrondo, L.J.; Liles, D.R.

    1980-01-01T23:59:59.000Z

    A brief review of the evolution of light-water reactor safety analysis codes is presented. Included is a summary comparison of the technical capabilities of major system codes. Three recent codes are described in more detail to serve as examples of currently used techniques. Example comparisons between calculated results using these codes and experimental data are given. Finally, a brief evaluation of current code capability and future development trends is presented.