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Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
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1

TRANSP simulations of International Thermonuclear Experimental Reactor plasmas  

E-Print Network (OSTI)

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

Budny, Robert

2

Economic Impacts on the United States of Siting Decisions for the International Thermonuclear Experimental Reactor  

Science Journals Connector (OSTI)

This paper 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) ...

J. P. Peerenboom; M. E. Hanson; J. R. Huddleston; T. D. Wolsko

1997-12-01T23:59:59.000Z

3

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

4

Management of waste from the International Thermonuclear Experimental Reactor and from future fusion power plants  

Science Journals Connector (OSTI)

An important inherent advantage of fusion would be the total absence of high-level radioactive spent fuel as produced in fission reactors. Fusion will, however, produce activated material containing both activation products and tritium. Part of the material may also contain chemically toxic substances. This paper describes methods that could be used to manage these materials and also methods to reduce or entirely eliminate the waste quantities. The results are based on studies for the International Thermonuclear Experimental Reactor (ITER) and also for future fusion power station designs currently under investigation within the European programme on the Safety and Environmental Assessment of fusion power, Long-term (SEAL).

Karin Brodén; Maria Lindberg; Simon Nisan; Paolo Rocco; Massimo Zucchetti; Neill Taylor; Cleve Forty

1997-01-01T23:59:59.000Z

5

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

SciTech Connect

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.

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

1996-08-01T23:59:59.000Z

6

Beryllium fabrication/cost assessment for ITER (International Thermonuclear Experimental Reactor)  

SciTech Connect

A fabrication and cost estimate of three possible beryllium shapes for the International Thermonuclear Experimental Reactor (ITER) blanket is presented. The fabrication method by hot pressing (HP), cold isostatic pressing plus sintering (CIP+S), cold isostatic pressing plus sintering plus hot isostatic pressing (CIP+S+HIP), and sphere production by atomization or rotary electrode will be discussed. Conventional hot pressing blocks of beryllium with subsequent machining to finished shapes can be more expensive than production of a net shape by cold isostatic pressing and sintering. The three beryllium shapes to be considered here and proposed for ITER are: (1) cubic blocks (3 to 17 cm on an edge), (2) tubular cylinders (33 to 50 mm i.d. by 62 mm o.d. by 8 m long), and (3) spheres (1--5 mm dia.). A rough cost estimate of the basic shape is presented which would need to be refined if the surface finish and tolerances required are better than the sintering process produces. The final cost of the beryllium in the blanket will depend largely on the machining and recycling of beryllium required to produce the finished product. The powder preparation will be discussed before shape fabrication. 10 refs., 6 figs.

Beeston, J.M. (Beeston (J.M.), Garrison, UT (USA)); Longhurst, G.R. (EG and G Idaho, Inc., Idaho Falls, ID (USA)); Parsonage, T. (Brush Wellman, Inc., Elmore, OH (USA))

1990-06-01T23:59:59.000Z

7

Toroidal field coil replacement study for the International Thermonuclear Experimental Reactor (ITER)  

SciTech Connect

The objective of this study is to develop an estimate of the time required to replace a failed toroidal field (TF) coil in the International Thermonuclear Experimental Reactor (ITER). This estimate is based on the current ITER design which resulted from the Conceptual Design Activities began in spring of 1988 and ending in December 1990. Although the TF Coils in ITER are designated permanent components and expected to last the life of the plant, the history of failures of large coils in fusion devices has prompted an assessment of the down time that might be required for replacement of a failed TF coil in ITER. The difficulty of replacement of a TF Coil in ITER is compounded by the large physical size of ITER, and the radiation fields which necessitate the use of remote handling equipment for most maintenance activities. Since 10 out of 16 TF coils are adjacent to either a Neutral Beam Injector (NBI) port or a remote handling (RH) port, it is probable that a failed TF Coil will be in one of these inconvenient locations. For this study, TF coil number 3 is assumed to fail and its replacement will be evaluated as a typical case. TF coil number 3 is located between a remote handling port ({number sign}3) and a port allocated to the lower hybrid ({number sign}4).

Not Available

1991-08-01T23:59:59.000Z

8

Toroidal field coil replacement study for the International Thermonuclear Experimental Reactor (ITER)  

SciTech Connect

The objective of this study is to develop an estimate of the time required to replace a failed toroidal field (TF) coil in the International Thermonuclear Experimental Reactor (ITER). This estimate is based on the current ITER design which resulted from the Conceptual Design Activities began in spring of 1988 and ending in December 1990. Although the TF Coils in ITER are designated permanent components and expected to last the life of the plant, the history of failures of large coils in fusion devices has prompted an assessment of the down time that might be required for replacement of a failed TF coil in ITER. The difficulty of replacement of a TF Coil in ITER is compounded by the large physical size of ITER, and the radiation fields which necessitate the use of remote handling equipment for most maintenance activities. Since 10 out of 16 TF coils are adjacent to either a Neutral Beam Injector (NBI) port or a remote handling (RH) port, it is probable that a failed TF Coil will be in one of these inconvenient locations. For this study, TF coil number 3 is assumed to fail and its replacement will be evaluated as a typical case. TF coil number 3 is located between a remote handling port ({number_sign}3) and a port allocated to the lower hybrid ({number_sign}4).

Not Available

1991-08-01T23:59:59.000Z

9

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)

03/01/2006 09:51 AMLoading "People's Daily Online -- Chinese experimental thermonuclear reactor experimental thermonuclear reactor on discharge test in July China's new generation experimental Tokamak fusion and the former Soviet Union launched a 10 billion- euro ambitious plan, the International Thermonuclear

10

Thermonuclear Reflect AB-Reactor  

E-Print Network (OSTI)

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.

Alexander Bolonkin

2008-03-26T23:59:59.000Z

11

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 misunderstood." Work to create a thermonuclear reactor has been pursued in all leading countries for several experimental thermonuclear reactor ITER in France. The project involves the European Union, America, Russia

12

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

SciTech Connect

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.

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

13

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

E-Print Network (OSTI)

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

André Gsponer; Jean-pierre Hurni

2004-01-01T23:59:59.000Z

14

Comparison of Nb/sub 3/Sn and NbTi superconductor magnet ITER (International Thermonuclear Experimental Reactor) devices  

SciTech Connect

The TETRA tokamak systems code is used to compare designs for the International Thermonuclear Experimental Reactor (ITER) that use Nb/sub 3/Sn and NbTi superconductor magnets. Similar minimum-cost devices are found with both types of conductors when superfluid helium (He-2) is used in conjunction with the NbTi. The cost of using NbTi with He-1 cooling is much higher than that of using Nb/sub 3/Sn or NbTi with He-2 cooling. Generally, the minimum-cost devices occur for peak fields at the toroidal field coil of about 11.5-13 T, depending on the physics requirements. Sensitivities to the allowable stress level indicate strong cost increases when the stress is reduced from the nominal 600-MPa level and weaker cost benefits when the stress is allowed to reach higher levels. 8 refs., 5 figs., 1 tab.

Galambos, J.D.; Peng, Y.K.M.; Reid, R.L.; Lubell, M.S.; Dresner, L.; Miller, J.R.

1988-01-01T23:59:59.000Z

15

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

16

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

17

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

18

Micro -Thermonuclear AB-Reactors for Aerospace  

E-Print Network (OSTI)

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).

Alexander Bolonkin

2007-01-08T23:59:59.000Z

19

New AB-Thermonuclear Reactor for Aerospace  

E-Print Network (OSTI)

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.

Alexander Bolonkin

2007-06-14T23:59:59.000Z

20

Stars as thermonuclear reactors: their fuels and ashes  

E-Print Network (OSTI)

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.

A. Ray

2004-05-28T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Thermalization and Exhaust of Helium in a Future Thermonuclear Reactor: Partly an Atomic Physics Problem  

Science Journals Connector (OSTI)

The magnetically confined plasma of a continuously or quasi-continuously working thermonuclear fusion reactor must satisfy several severe conditions in ... the a-particles born in the D-T fusion process, the othe...

H. W. Drawin

1980-01-01T23:59:59.000Z

22

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

E-Print Network (OSTI)

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...

Pearce, James David

1975-01-01T23:59:59.000Z

23

INTERNATIONAL THERMONUCLEAR EXPERIMENTAL REACTOR TECHNICAL BASIS  

E-Print Network (OSTI)

Analysis (FDR)1 (the 1998 ITER design), supported by a body of scientific and technological data which both - to demonstrate the scientific and technological feasibility of fusion energy for peaceful purposes - and complied and Thermal Shields II.4 Fuel Cycle II.5 Water Cooling System II.6 Plasma Diagnostic System II.7 Heating

24

Finite element modeling and experimental study of brittle fracture in tempered martensitic steels for thermonuclear fusion applications.  

E-Print Network (OSTI)

??In this work we have studied brittle fracture in high-chromium reduced activation tempered martensitic steels foreseen as structural materials for thermonuclear fusion reactors. Developing the… (more)

Mueller, Pablo Federico

2009-01-01T23:59:59.000Z

25

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 is well advanced through the International Thermonuclear Experimental Reactor (ITER) programme, which has

26

E-Print Network 3.0 - advanced fission reactors Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

fission reactors, which release energy by splitting atoms... ) International Thermonuclear Experimental Reactor (ITER), which will be ... Source: Fusiongnition Research...

27

Astrophysical thermonuclear functions  

E-Print Network (OSTI)

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).

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

1993-08-23T23:59:59.000Z

28

Thermonuclear inverse magnetic pumping power cycle for stellarator reactor  

DOE Patents (OSTI)

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.

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

1991-01-01T23:59:59.000Z

29

Experimental evidence of thermonuclear neutrons in a modified plasma focus  

Science Journals Connector (OSTI)

The PF-1000 plasma focus was modified by adding the cathode disk 3 cm in front of the anode. This modification facilitated the evaluation of neutron energy spectra. Two neutron pulses were distinguishable. As regards the first neutron pulse it lasted 40 ns during the plasma stagnation and it demonstrated high isotropy of neutron emission. A peak neutronenergydetected upstream was 2.46 ± 0.02 ? MeV . The full width of neutron energy spectra of 90 ± 20 ? keV enabled to calculate an ion temperature of 1.2 keV. These parameters and a neutron yield of 10 9 corresponded to theoretical predictions for thermonuclear neutrons.

D. Klir; P. Kubes; M. Paduch; T. Pisarczyk; T. Chodukowski; M. Scholz; Z. Kalinowska; E. Zielinska; B. Bienkowska; J. Hitschfel; S. Jednorog; L. Karpinski; J. Kortanek; J. Kravarik; K. Rezac; I. Ivanova-Stanik; K. Tomaszewski

2011-01-01T23:59:59.000Z

30

Choice of coils for a fusion reactor  

Science Journals Connector (OSTI)

...configurations. The most ambitious is the International Thermonuclear Experimental Reactor, a large tokamak planned for construction...configuration has features in common with the International Thermonuclear Experimental Reactor experiment. Mathematical Model We...

Romeo Alexander; Paul R. Garabedian

2007-01-01T23:59:59.000Z

31

Thermonuclear power—A major international innovative project  

Science Journals Connector (OSTI)

Current status review of a tokamak reactor-based research is intended for the average readers. Using the project of International Thermonuclear Experimental Reactor (ITER) as an example, physical and engineeri...

V. P. Smirnov

2009-11-01T23:59:59.000Z

32

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)

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

Vlad, Gregorio

33

E-Print Network 3.0 - aged reactor pressure Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

effort Summary: plan to build a 5 billion fusion reactor, called the International Thermonuclear Experimental Reactor... could be achieved in 35 years. "By the time our young...

34

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

NLE Websites -- All DOE Office Websites (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...

35

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

NLE Websites -- All DOE Office Websites (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...

36

E-Print Network 3.0 - advanced marine reactor Sample Search Results  

NLE Websites -- All DOE Office Websites (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...

37

E-Print Network 3.0 - almaty wwr-k reactor Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

High Flux Isotope Reactor Center for Nanophase Materials Sciences... International Thermonuclear Experimental Reactor Center for Computational Sciences National Security 0 0 61 1...

38

E-Print Network 3.0 - austrian research reactor Sample Search...  

NLE Websites -- All DOE Office Websites (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...

39

E-Print Network 3.0 - anuclear research reactor Sample Search...  

NLE Websites -- All DOE Office Websites (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...

40

E-Print Network 3.0 - advanced hanaro reactor Sample Search Results  

NLE Websites -- All DOE Office Websites (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...

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

E-Print Network 3.0 - athene reactor Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

which country... will host a nuclear fusion reactor for the International Thermonuclear Experimental Reactor (ITER) project... . The candidate sites for the international...

42

E-Print Network 3.0 - atomic reactors nouvelles Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

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

43

The development of structural materials for fusion reactors  

Science Journals Connector (OSTI)

...severely exposed parts of future fusion reactors and pose key problems...successful implementation of fusion reactors as an efficient source...conditions in the International Thermonuclear Experimental Reactor (ITER...environmental attractiveness of fusion reactors. In this paper...

1999-01-01T23:59:59.000Z

44

Astrophysical thermonuclear functions  

E-Print Network (OSTI)

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.

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

1994-02-08T23:59:59.000Z

45

E-Print Network 3.0 - advanced reactor study Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Hotel bargains... to iron out their differences over the site of the International Thermonuclear Experimental Reactor Source: Fusiongnition Research Experiment (FIRE) Collection:...

46

E-Print Network 3.0 - advanced fusion reactors Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

fusion plant deal 1 hour, 28 minutes ago Representatives of more... ) International Thermonuclear Experimental Reactor (ITER), which will be built at ... Source: Fusiongnition...

47

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

NLE Websites -- All DOE Office Websites (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...

48

E-Print Network 3.0 - australian moata reactor Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

was expected on breaking... the deadlock over where to base the International Thermonuclear Experimental Reactor (ITER), the officials... for 20 years. The six parties failed...

49

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

NLE Websites -- All DOE Office Websites (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...

50

E-Print Network 3.0 - advanced converter reactors Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

computer network ring for advance science and education cooperation in Beijing... thermonuclear experimental reactor (ITER) project have an opportunity to offer technical...

51

International Effort to Design Nuclear Fusion Reactor Launched  

Science Journals Connector (OSTI)

International Effort to Design Nuclear Fusion Reactor Launched ... Their mission is to draw up a design concept for a thermonuclear fusion reactor by December 1990. ... The work at Garching is a direct outgrowth of the recently signed International Thermonuclear Experimental Reactor (ITER) pact involving the European Community, Japan, the Soviet Union, and the U.S. (C&EN, April 25, page 19). ...

DERMOT A. O'SULLLVAN

1988-05-23T23:59:59.000Z

52

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

E-Print Network (OSTI)

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.

S. I. Fisenko; I. S. Fisenko

2007-05-27T23:59:59.000Z

53

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

E-Print Network (OSTI)

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.

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

54

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)

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.

Woolley, Robert D. (Belle Mead, NJ)

1999-01-01T23:59:59.000Z

55

Thermonuclear Supernovae  

E-Print Network (OSTI)

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.

F. K. Roepke

2008-04-14T23:59:59.000Z

56

ASTROPHYSICAL THERMONUCLEAR FUNCTIONS  

E-Print Network (OSTI)

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

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

1993-01-01T23:59:59.000Z

57

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

E-Print Network (OSTI)

be able to move directly and safely to a "first of a kind" reactor. The main conditions to be satisfied / experimental evidence. To assess the reactor relevance of ITER, rather than a comparison between ITER and one1 How far is a Fusion Power Reactor from an Experimental Reactor? R. Toschi(1) , P. Barabaschi(2

58

Opportunities in the Construction Phase of the International Thermonuclear Experimental Reactor  

Science Journals Connector (OSTI)

Since 1992, fusion researchers from the U.S., Japan, Europe, Russia, and other countries, have been engaged in a very successful collaboration on the engineering design activities (EDA) of the world's first fu...

S. O. Dean; W. R. Ellis; A. Favale; H. Forsen; C. Hamilton…

1999-06-01T23:59:59.000Z

59

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

E-Print Network (OSTI)

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.

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

2007-05-07T23:59:59.000Z

60

Experimental and Computational Study of Fluid Dynamics in Solar Reactor  

E-Print Network (OSTI)

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...

Chien, Min-Hsiu

2014-02-19T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

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

E-Print Network (OSTI)

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

Navaei, Dara

2011-01-01T23:59:59.000Z

62

E-Print Network 3.0 - advanced test reactor Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

20 03012006 09:51 AMLoading "People's Daily Online --Chinese experimental thermonuclear reactor on discharge test in July" Page 1 of 1http:english.people.com.cn200603...

63

Plasma-Sprayed Beryllium on Macro-Roughened Substrates for Fusion Reactor High Heat Flux Applications  

Science Journals Connector (OSTI)

The development of beryllium first wall (FW) plasma facing components for future magnetic confinement fusion experiments, such as the International Thermonuclear Experimental Reactor (ITER), is a topic of great.....

Kendall J. Hollis; Brian D. Bartram; Manfred Roedig…

2007-03-01T23:59:59.000Z

64

Study of MHD Corrosion and Transport of Corrosion Products of Ferritic/Martensitic Steels in the Flowing PbLi and its Application to Fusion Blanket  

E-Print Network (OSTI)

Metal systems of thermonuclear reactors, energoatomizdat, inITER International Thermonuclear Experimental Reactor HCLLin ITER (International Thermonuclear Experimental Reactor) (

Saeidi, Sheida

2014-01-01T23:59:59.000Z

65

Simplest AB-Thermonuclear Space Propulsion and Electric Generator  

E-Print Network (OSTI)

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.

Alexander Bolonkin

2007-01-19T23:59:59.000Z

66

Generation of thermonuclear energy by fusing hydrogen and lithium atoms  

Science Journals Connector (OSTI)

A method of designing a thermonuclear reactor based on the modified Cockroft-Walton accelerator, where the lithium-proton fusion was first observed, is considered. It...15 W/cm2...to the cathode are determined. T...

V. E. Tyrsa; L. P. Burtseva

2003-07-01T23:59:59.000Z

67

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

E-Print Network (OSTI)

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

Kosuga, Yusuke

2012-01-01T23:59:59.000Z

68

Japan's tokamak success boosts its bid for reactor  

Science Journals Connector (OSTI)

... Tokyo. Japan's upgraded tokamak fusion reactor, JT-60U, has achieved a long sought-after goal ... conditions 'equivalent' to breakeven, where energy output equals energy input. This will strengthen Japan's bid to host the International Thermonuclear Experimental Reactor (ITER), if the machine, ...

David Swinbanks

1996-11-14T23:59:59.000Z

69

Experimental Criticality Benchmarks for SNAP 10A/2 Reactor Cores  

SciTech Connect

This report describes computational benchmark models for nuclear criticality derived from descriptions of the Systems for Nuclear Auxiliary Power (SNAP) Critical Assembly (SCA)-4B experimental criticality program conducted by Atomics International during the early 1960's. The selected experimental configurations consist of fueled SNAP 10A/2-type reactor cores subject to varied conditions of water immersion and reflection under experimental control to measure neutron multiplication. SNAP 10A/2-type reactor cores are compact volumes fueled and moderated with the hydride of highly enriched uranium-zirconium alloy. Specifications for the materials and geometry needed to describe a given experimental configuration for a model using MCNP5 are provided. The material and geometry specifications are adequate to permit user development of input for alternative nuclear safety codes, such as KENO. A total of 73 distinct experimental configurations are described.

Krass, A.W.

2005-12-19T23:59:59.000Z

70

Thermonuclear Ignition of Dark Galaxies  

E-Print Network (OSTI)

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

J. Marvin Herndon

2006-01-01T23:59:59.000Z

71

Prediction of Thermonuclear Reaction Rates in Astrophysics  

E-Print Network (OSTI)

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.

T. Rauscher

1998-10-15T23:59:59.000Z

72

Princeton Plasma Physics Laboratory NSTX Experimental Proposal  

E-Print Network (OSTI)

Princeton Plasma Physics Laboratory NSTX Experimental Proposal Title: Dependence of ELM size Thermonuclear Experimental Reactor (ITER) have yielded a pedestal energy loss fraction between 5% and 20 with resonant magnetic perturbations2 or by access to small ELM regimes. Fig. 1 from reference1 , where

Princeton Plasma Physics Laboratory

73

Princeton Plasma Physics Laboratory NSTX Experimental Proposal  

E-Print Network (OSTI)

Princeton Plasma Physics Laboratory NSTX Experimental Proposal Title: Dependence of ELM size Projections1 of the energy loss from Type I ELMs for the International Thermonuclear Experimental Reactor perturbations2 or by access to small ELM regimes. Fig. 1 from reference1 , where extrapolation to ITER is done

Princeton Plasma Physics Laboratory

74

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

E-Print Network (OSTI)

Rôle de l’énergie de fusion dans la production énergétique du 21 e siècle et stratégie de développement avec le réacteur thermonucléaire international ITER

Kikuchi Mitsuru

75

Formation and sustainment of internal transport barriers in the International Thermonuclear Experimental Reactor with the baseline heating mix  

SciTech Connect

Plasmas with internal transport barriers (ITBs) are a potential and attractive route to steady-state operation in ITER. These plasmas exhibit radially localized regions of improved confinement with steep pressure gradients in the plasma core, which drive large bootstrap current and generate hollow current profiles and negative magnetic shear. This work examines the formation and sustainment of ITBs in ITER with electron cyclotron heating and current drive. The time-dependent transport simulations indicate that, with a trade-off of the power delivered to the equatorial and to the upper launcher, the sustainment of steady-state ITBs can be demonstrated in ITER with the baseline heating configuration.

Poli, Francesca M.; Kessel, Charles E. [Princeton Plasma Physics laboratory, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics laboratory, Princeton, New Jersey 08543 (United States)

2013-05-15T23:59:59.000Z

76

Design, performance, and grounding aspects of the International Thermonuclear Experimental Reactor ion cyclotron range of frequencies antenna  

SciTech Connect

ITER's Ion Cyclotron Range of Frequencies (ICRF) system [Lamalle et al., Fusion Eng. Des. 88, 517–520 (2013)] comprises two antenna launchers designed by CYCLE (a consortium of European associations listed in the author affiliations above) on behalf of ITER Organisation (IO), each inserted as a Port Plug (PP) into one of ITER's Vacuum Vessel (VV) ports. Each launcher is an array of 4 toroidal by 6 poloidal RF current straps specified to couple up to 20?MW in total to the plasma in the frequency range of 40 to 55 MHz but limited to a maximum system voltage of 45?kV and limits on RF electric fields depending on their location and direction with respect to, respectively, the torus vacuum and the toroidal magnetic field. A crucial aspect of coupling ICRF power to plasmas is the knowledge of the plasma density profiles in the Scrape-Off Layer (SOL) and the location of the RF current straps with respect to the SOL. The launcher layout and details were optimized and its performance estimated for a worst case SOL provided by the IO. The paper summarizes the estimated performance obtained within the operational parameter space specified by IO. Aspects of the RF grounding of the whole antenna PP to the VV port and the effect of the voids between the PP and the Blanket Shielding Modules (BSM) surrounding the antenna front are discussed. These blanket modules, whose dimensions are of the order of the ICRF wavelengths, together with the clearance gaps between them will constitute a corrugated structure which will interact with the electromagnetic waves launched by ICRF antennas. The conditions in which the grooves constituted by the clearance gaps between the blanket modules can become resonant are studied. Simple analytical models and numerical simulations show that mushroom type structures (with larger gaps at the back than at the front) can bring down the resonance frequencies, which could lead to large voltages in the gaps between the blanket modules and perturb the RF properties of the antenna if they are in the ICRF operating range. The effect on the wave propagation along the wall structure, which is acting as a spatially periodic (toroidally and poloidally) corrugated structure, and hence constitutes a slow wave structure modifying the wall boundary condition, is examined.

Durodié, F., E-mail: frederic.durodie@rma.ac.be; Dumortier, P.; Vrancken, M.; Messiaen, A.; Huygen, S.; Louche, F.; Van Schoor, M.; Vervier, M. [LPP-ERM/KMS, Association EURATOM-Belgian State, Brussels (Belgium); Bamber, R.; Hancock, D.; Lockley, D.; Nightingale, M. P. S.; Shannon, M.; Tigwell, P.; Wilson, D. [EURATOM/CCFE Assoc., Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Maggiora, R.; Milanesio, D. [Associazione EURATOM-ENEA, Politechnico di Torino (Italy); Winkler, K. [IPP-MPI, EURATOM-Assoziation, Garching (Germany)

2014-06-15T23:59:59.000Z

77

Incipient Transient Detection in Reactor Systems: Experimental and Theoretical Investigation  

SciTech Connect

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).

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

2005-09-27T23:59:59.000Z

78

AEC Pushes Fusion Reactors  

Science Journals Connector (OSTI)

AEC Pushes Fusion Reactors ... Project Sherwood, as the study program is called, began in 1951-52 soon after the first successful thermonuclear explosion in the Pacific. ...

1955-10-10T23:59:59.000Z

79

A low-radioactive D-3He thermonuclear fuel cycle with 3He self-supply  

Science Journals Connector (OSTI)

The possibility of implementing a highly efficient low-radioactive thermonuclear fuel cycle using deuterium as the raw...3He reaction, with 3He obtained in the course of the reactor operation. It is shown that, u...

V. I. Khvesyuk; A. Yu. Chirkov

2001-08-01T23:59:59.000Z

80

Contribution of different mechanisms of energy transfer in the development of the thermonuclear combustion wave upon fast ignition of ICF-targets  

Science Journals Connector (OSTI)

Temporal characteristics of the thermonuclear combustion wave, critical parameters of the igniter ... fast ignition of the spherically symmetric inertial confinement fusion (ICF) target of the reactor type ... co...

N. B. Gubinskaya; S. Yu. Gus’kov; D. V. Il’in…

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Japan prepares to pitch for international fusion reactor  

Science Journals Connector (OSTI)

... Japan has taken another tentative step towards hosting the International Thermonuclear Experimental Reactor (ITER), ... 's Atomic Energy Commission approved a report supporting construction of the multibillion dollar project in Japan. But the commission also emphasized that hosting the facility must not harm existing Japanese ...

David Cyranoski

2001-04-19T23:59:59.000Z

82

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

Energy.gov (U.S. Department of Energy (DOE))

Presents experimental study of a Cu-zeolite SCR in both reactor and engine test cell, and comparison of the model parameters between the SCR reactor and engine model

83

Electron Screening Effect on Stellar Thermonuclear Fusion  

E-Print Network (OSTI)

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

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

84

Implications of Thermonuclear-Fusion Energy Systems  

E-Print Network (OSTI)

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

André Gsponer; Jean-pierre Hurni

2004-01-01T23:59:59.000Z

85

Experimental Breeder Reactor-II Primary Tank System Wash Water Workshop  

Energy.gov (U.S. Department of Energy (DOE))

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

86

Laser Fusion Experimental Reactor LIFT Based on Fast Ignition and the Issue  

Science Journals Connector (OSTI)

We organized a design committee for the laser fusion experimental reactor to show the feasibility to construct it with existing materials and improved technologies. The ...

Norimatsu, Takayoshi; Kozaki, Yasuji; Shiraga, Hiroshi; Fujita, Hisanori; Okano, Kunihiko; Azech, Hiroshi

87

Experimental Highlights  

NLE Websites -- All DOE Office Websites (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...

88

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

SciTech Connect

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)

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

89

Public comment sought on final end state of Experimental Breeder Reactor-II  

NLE Websites -- All DOE Office Websites (Extended Search)

Media Contacts: Danielle Miller, 208-526-5709 Media Contacts: Danielle Miller, 208-526-5709 Joseph Campbell, CWI, 208-360-0142 Public comment sought on final end state of Experimental Breeder Reactor-II The U.S. Department of Energy (DOE) is seeking public comment on a range of alternatives for disposition of the landmark Experimental Breeder Reactor-II (EBR-II) building and reactor vessel at the Idaho Site's Materials and Fuels Complex. An Engineering Evaluation/Cost Analysis (EE/CA) document with four proposed alternatives for the final end state of the reactor facility and support structures is currently under evaluation by DOE, the U.S. Environmental Protection Agency, and Idaho's Department of Environmental Quality. Experimental Breeder Reactor-II containment dome The EBR-II was an innovative sodium-cooled reactor with an output of 62

90

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

E-Print Network (OSTI)

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.

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

1996-08-07T23:59:59.000Z

91

President Truman Orders Development of Thermonuclear Weapon ...  

NLE Websites -- All DOE Office Websites (Extended Search)

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

92

First Thermonuclear Device Successfully Tested | National Nuclear...  

National Nuclear Security Administration (NNSA)

Thermonuclear Device Successfully Tested | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile Preventing...

93

Merging white dwarfs and thermonuclear supernovae  

Science Journals Connector (OSTI)

...across the Universe . Thermonuclear supernovae result when...companion reignites nuclear fusion in a carbon-oxygen white dwarf, causing a thermonuclear runaway, a catastrophic...adiabatically, until carbon fusion becomes faster than...time scales and the thermonuclear runaway starts (along...

2013-01-01T23:59:59.000Z

94

A comparison of radioactive waste from first generation fusion reactors and fast fission reactors with actinide recycling  

SciTech Connect

Limitations of the fission fuel resources will presumably mandate the replacement of thermal fission reactors by fast fission reactors that operate on a self-sufficient closed fuel cycle. This replacement might take place within the next one hundred years, so the direct competitors of fusion reactors will be fission reactors of the latter rather than the former type. Also, fast fission reactors, in contrast to thermal fission reactors, have the potential for transmuting long-lived actinides into short-lived fission products. The associated reduction of the long-term activation of radioactive waste due to actinides makes the comparison of radioactive waste from fast fission reactors to that from fusion reactors more rewarding than the comparison of radioactive waste from thermal fission reactors to that from fusion reactors. Radioactive waste from an experimental and a commercial fast fission reactor and an experimental and a commercial fusion reactor has been characterized. The fast fission reactors chosen for this study were the Experimental Breeder Reactor 2 and the Integral Fast Reactor. The fusion reactors chosen for this study were the International Thermonuclear Experimental Reactor and a Reduced Activation Ferrite Helium Tokamak. The comparison of radioactive waste parameters shows that radioactive waste from the experimental fast fission reactor may be less hazardous than that from the experimental fusion reactor. Inclusion of the actinides would reverse this conclusion only in the long-term. Radioactive waste from the commercial fusion reactor may always be less hazardous than that from the commercial fast fission reactor, irrespective of the inclusion or exclusion of the actinides. The fusion waste would even be far less hazardous, if advanced structural materials, like silicon carbide or vanadium alloy, were employed.

Koch, M.; Kazimi, M.S.

1991-04-01T23:59:59.000Z

95

New Views of Thermonuclear Bursts  

E-Print Network (OSTI)

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.

Tod Strohmayer; Lars Bildsten

2003-05-06T23:59:59.000Z

96

Thermonuclear Ignition of Dark Galaxies  

E-Print Network (OSTI)

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.

J. Marvin Herndon

2006-04-13T23:59:59.000Z

97

An evaluation of alternative reactor vessel cutting technologies for the experimental boiling water reactor at Argonne National Laboratory  

SciTech Connect

Metal cutting techniques that can be used to segment the reactor pressure vessel of the Experimental Boiling Water Reactor (EBWR) at Argonne National Laboratory (ANL) have been evaluated by Nuclear Energy Services. Twelve cutting technologies are described in terms of their ability to perform the required task, their performance characteristics, environmental and radiological impacts, and cost and schedule considerations. Specific recommendations regarding which technology should ultimately be used by ANL are included. The selection of a cutting method was the responsibility of the decommissioning staff at ANL, who included a relative weighting of the parameters described in this document in their evaluation process. 73 refs., 26 figs., 69 tabs.

Boing, L.E.; Henley, D.R. (Argonne National Lab., IL (USA)); Manion, W.J.; Gordon, J.W. (Nuclear Energy Services, Inc., Danbury, CT (USA))

1989-12-01T23:59:59.000Z

98

Search for thermonuclear neutrons in a mega-ampere plasma focus  

Science Journals Connector (OSTI)

Plasma focus experiments were carried out at a modified PF-1000 where the cathode disc was added in front of the anode. Experimental results indicated a fraction of thermonuclear neutrons on the mega-ampere current level. In order to prove the thermonuclear mechanism, the time of neutron production and the neutron energy spectrum were measured by time-of-flight (TOF) diagnostics. Neutron TOF signals showed that the neutron production was a multiphase process and more than one mechanism occurred simultaneously. The occurrence of the thermonuclear mechanism was most evident during the plasma stagnation at low deuterium pressures. At low filling pressures, the narrow width of the neutron energy spectra demonstrated an ion temperature of about 1?keV. The possibility of thermonuclear neutrons was studied also after the stagnation, during the main neutron emission. In this case, the thermonuclear mechanism could be verified by calculating the number of deuterons that participate in the fusion process. For the bulk of thermonuclear plasmas, a significant fraction of plasma should participate in fusion. Finally, the basic consideration of the thermonuclear mechanism in Z-pinches showed the reasonableness of the MagLIF concept.

D Klir; P Kubes; M Paduch; T Pisarczyk; T Chodukowski; M Scholz; Z Kalinowska; B Bienkowska; L Karpinski; J Kortanek; J Kravarik; K Rezac; I Ivanova-Stanik; K Tomaszewski; E Zielinska

2012-01-01T23:59:59.000Z

99

Experimental Highlights - 2014  

NLE Websites -- All DOE Office Websites (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...

100

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

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

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)

for the integration have been developed and the interfaces with the re to their anticipated operational role (machine protection, control and physics studies). About 45 parameters in total). These are included in the highest level ITER design requirement document (DRG 1). · For each parameter

102

Experimental Studies of NGNP Reactor Cavity Cooling System With Water  

SciTech Connect

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.

Michael Corradini; Mark Anderson; Yassin Hassan; Akira Tokuhiro

2013-01-16T23:59:59.000Z

103

Experimental determination of neutron lifetimes through macroscopic neutron noise in the IPEN/MB-01 reactor  

SciTech Connect

The neutron lifetimes of the core, reflector, and global were experimentally obtained through macroscopic neutron noise in the IPEN/MB-01 reactor for five levels of subcriticality. The theoretical Auto Power Spectral Densities were derived by point kinetic equations taking the reflector effect into account, and one of the approaches consider an additional group of delayed neutrons.

Gonnelli, Eduardo; Diniz, Ricardo [Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP Travessa R-400, 05508-900, Cidade Universitaria, Sao Paulo (Brazil)

2013-05-06T23:59:59.000Z

104

Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations  

E-Print Network (OSTI)

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 ...

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

2014-01-01T23:59:59.000Z

105

Thermonuclear burst physics with RXTE  

E-Print Network (OSTI)

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.

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

2004-04-22T23:59:59.000Z

106

Tidally-induced thermonuclear Supernovae  

E-Print Network (OSTI)

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.

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

2008-11-13T23:59:59.000Z

107

The physics of antimatter induced fusion and thermonuclear explosions  

E-Print Network (OSTI)

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

Andre Gsponer; Jean-pierre Hurni

108

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

109

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

SciTech Connect

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.

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

110

Laser-Induced Implosion and Thermonuclear Burn  

Science Journals Connector (OSTI)

In high density laser induced fusion, the key idea is laser implosion of ... times liquid density in order to initiate efficient thermonuclear burningl. Fusion yields 50–100 times larger than the...5–106...joules...

John H. Nuckolls

1974-01-01T23:59:59.000Z

111

ITER: an integrated approcah to ignited plasmas  

Science Journals Connector (OSTI)

...International Thermonuclear Experimental...demonstrate essential fusion reactor technologies...poten- tial of thermonuclear fusion as a practical...International Thermonuclear Experimental...world's leading fusion programmes...

1999-01-01T23:59:59.000Z

112

UV Light Curves of Thermonuclear Supernovae  

E-Print Network (OSTI)

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.

S. I. Blinnikov; E. I. Sorokina

2000-03-17T23:59:59.000Z

113

Experimental Breeder Reactor-II Primary Tank System Wash Water Workshop  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Pre-Developmental Pre-Developmental INL EBR-II Wash Water Treatment Technologies (PBS # ADSHQTD0100 (0003199)) EBR-II Wash Water Workshop - The majority of the sodium has been removed, remaining material is mostly passivated. Similar closure projects have been successfully completed. Engineering needs to be developed to apply the OBA path. Page 1 of 2 Idaho National Laboratory Idaho Experimental Breeder Reactor-II Primary Tank System Wash Water Workshop Challenge In 1994 Congress ordered the shutdown of the Experimental Breeder Reactor-II (EBR-II) and a closure project was initiated. The facility was placed in cold shutdown, engineering began on sodium removal, the sodium was drained in 2001 and the residual sodium chemically passivated to render it less reactive in 2005. Since that time, approximately 700 kg of metallic sodium and 3500 kg of sodium bicarbonate remain in the facility. The

114

E-Print Network 3.0 - advanced passive reactor Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

... Source: Fusiongnition Research Experiment (FIRE) Collection: Plasma Physics and Fusion 37 ITER --"INTERNATIONAL THERMONUCLEAR EXPERIMENTAL RESEARCH PROGRAM". Summary:...

115

White dwarf mergers,White dwarf mergers, thermonuclear supernovae,thermonuclear supernovae,  

E-Print Network (OSTI)

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

Hinton, Jim

116

Fast response neutron emission monitor for fusion reactor using Stilbene Scintillator and Flash-ADC  

Science Journals Connector (OSTI)

......response neutron emission monitor for fusion reactor using Stilbene Scintillator and...the most important techniques at fusion reactors, including International Thermonuclear...neutron emission from a nuclear fusion reactor in recent years(10-13......

T. Itoga; M. Ishikawa; M. Baba; T. Okuji; T. Oishi; M. Nakhostin; T. Nishitani

2007-08-01T23:59:59.000Z

117

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

SciTech Connect

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.

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

118

Electron Screening Effect on Stellar Thermonuclear Fusion  

E-Print Network (OSTI)

Key words Dense matter, stellar nucleosynthesis. 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 theoretical results on stellar thermonuclear fusions and show that these scenarios do not apply to stellar conditions. c ? 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1

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

119

Antimatter induced fusion and thermonuclear explosions  

E-Print Network (OSTI)

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.

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

1987-01-01T23:59:59.000Z

120

Modeling and Experimental Tests on the Hydraulically Driven Control Rod option for IRIS Reactor  

SciTech Connect

The adoption of Internal Control Rod Drive Mechanisms (ICRDMs) represents a valuable alternative to classical, external CRDMs based on electro-magnetic devices, as adopted in current PWRs. The advantages on the safety features of the reactor are apparent: inherent elimination of the Rod Ejection accidents and of possible concerns about the vessel head penetrations. A further positive feedback on the design is the reduction of the primary system overall dimensions. Within the frame of the ICRDM concepts, the Hydraulically Driven Control Rod solution is investigated as a possible option for the IRIS integral reactor. After a brief comparison of the solutions currently proposed for integral reactors, the configuration of the Hydraulic Control Rod device for IRIS, made up by an external movable piston and an internal fixed cylinder, is described. A description of the whole control system is reported as well. Particular attention is devoted to the Control Rod profile characterization, performed by means of a Computational Fluid Dynamics (CFD) analysis. The investigation of the system behavior has been carried out, including the dynamic equilibrium and its stability properties, the withdrawal and insertion step movement and the sensitivity study on command time periods. A suitable dynamic model has been set up for the mentioned purposes: the models corresponding to the various Control Rod system devices have been written in an Object-Oriented language (Modelica), thus allowing an easy implementation of such a system into the simulator for the whole reactor. Finally, a preliminary low pressure, low temperature, reduced length experimental facility has been built. Tests on HDCR stability and operational transients have been performed. The results are compared with the dynamic system model and CFD simulation model, showing good agreement between simulations and experimental data. During these preliminary tests, the control system performed correctly, allowing stable dynamic equilibrium positions for the Control Rod and stable behavior during withdrawal and insertion steps. (authors)

Cammi, Antonio; Ricotti, Marco E.; Vitulo, Alessia [Department of Nuclear Engineering, Politecnico di Milano, Via Ponzio, 34/3, 20133 Milano (Italy)

2004-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

E-Print Network 3.0 - ab-thermonuclear space propulsion Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

thermonuclear space propulsion Search Powered by Explorit Topic List Advanced Search Sample search results for: ab-thermonuclear...

122

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

E-Print Network (OSTI)

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

Holdener, Dain Steffen

2011-01-01T23:59:59.000Z

123

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

124

Three-dimensional equilibria in axially symmetric tokamaks  

Science Journals Connector (OSTI)

...General Atomic and the International Thermonuclear Experimental Reactor. When bifurcated...advanced tokamaks like the International Thermonuclear Experimental Reactor (ITER). We have computed...General Atomic and the International Thermonuclear Experimental Reactor. When bifurcated...

Paul R. Garabedian

2006-01-01T23:59:59.000Z

125

Three-dimensional analysis of tokamaks and stellarators  

Science Journals Connector (OSTI)

...are encountered in the International Thermonuclear Experimental Reactor (ITER) project...symmetry for a model of the International Thermonuclear Experimental Reactor (ITER) tokamak, and we discuss...are encountered in the International Thermonuclear Experimental Reactor (ITER) project...

Paul R. Garabedian

2008-01-01T23:59:59.000Z

126

EXPERIMENTAL EVALUATION OF THE THERMAL PERFORMANCE OF A WATER SHIELD FOR A SURFACE POWER REACTOR  

SciTech Connect

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 C. The CFD model with 1/6-g predicts a maximum water temperature of 88 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.

REID, ROBERT S. [Los Alamos National Laboratory; PEARSON, J. BOSIE [Los Alamos National Laboratory; STEWART, ERIC T. [Los Alamos National Laboratory

2007-01-16T23:59:59.000Z

127

Resonances and the thermonuclear reaction rate  

E-Print Network (OSTI)

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.

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

2003-07-21T23:59:59.000Z

128

Status and problems of fusion reactor development  

Science Journals Connector (OSTI)

Thermonuclear fusion of deuterium and tritium constitutes an enormous ... inexhaustible. Further, the safety prospects of a fusion reactor are quite favourable due to the inherently self-limiting fusion process,...

Uwe Schumacher

2001-03-01T23:59:59.000Z

129

First Thermonuclear Device Successfully Tested | National Nuclear Security  

NLE Websites -- All DOE Office Websites (Extended Search)

Thermonuclear Device Successfully Tested | National Nuclear Security Thermonuclear Device Successfully Tested | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog Home > About Us > Our History > NNSA Timeline > First Thermonuclear Device Successfully Tested First Thermonuclear Device Successfully Tested December 31, 1952 Enewetak Atoll First Thermonuclear Device Successfully Tested

130

Experimental and Computational Study of a Scaled Reactor Cavity Cooling System  

E-Print Network (OSTI)

The Very High Temperature Gas-Cooled Reactor (VHTR) is one of the next generation nuclear reactors designed to achieve high temperatures to support industrial applications and power generation. The Reactor Cavity Cooling System (RCCS) is a passive...

Vaghetto, Rodolfo

2013-11-25T23:59:59.000Z

131

Condensed hydrogen for thermonuclear fusion  

SciTech Connect

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.

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

132

Neutron capture of 26Mg at thermonuclear energies  

E-Print Network (OSTI)

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.

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

1998-05-20T23:59:59.000Z

133

Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations  

E-Print Network (OSTI)

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.

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

2014-09-19T23:59:59.000Z

134

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

135

France, June 28 Environmental  

E-Print Network (OSTI)

the International Thermonuclear Experimental Reactor was a hazard because scientists did not yet know how | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Google It: International Thermonuclear Experimental Reactor Sortir Du Nucleaire Masatoshi Koshiba

136

Merging White Dwarfs and Thermonuclear Supernovae  

E-Print Network (OSTI)

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.

van Kerkwijk, Marten H

2012-01-01T23:59:59.000Z

137

Calculational-experimental research models for a fast reactor with a heterogeneous core  

SciTech Connect

The physical characteristics of heterogeneous metallic oxide cores were experimentally studied by physical tests of the critical assemblies BFS-46 and BFS-46AZ, which simulate a reactor of the BN-1600 type, into the core of which a fuel assembly with metallic uranium is inserted. A calculational model for the critical assemblies being investigated, showing the zones and their dimensions, is presented. The critical assembly BFS-46AZ is a modification of the basic critical assembly BFS-46 which adds plutonium to the IBZ to simulate its accumulation during reactor operation. The BFS-46 and BFS-46AZ assemblies have identical dimensions for the IBZ and LEZ, and have different HEZ dimensions, necessary to ensure the criticality of each assembly. Plutonium with a /sup 240/Pu content equal to 3.8% is used in the LEZ. The critically parameters are calculated using one-dimensional and two-dimensional models in a 26-group diffusion approximation based on the BNAP-78 system of group constants.

Belov, S.P.; Bobrov, S.B.; Kazanskii, Yu.A.; Kuzin, E.N.; Matveev, V.I.; Novozhilov, A.I.; Chernyi, V.A.

1987-11-01T23:59:59.000Z

138

Solar Models and NACRE thermonuclear reaction rates  

E-Print Network (OSTI)

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.

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

1999-07-27T23:59:59.000Z

139

Thermonuclear processes of the Universe  

E-Print Network (OSTI)

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.

Sergey B. Dubovichenko

2011-08-12T23:59:59.000Z

140

MTG fluidized bed reactor–regenerator unit with catalyst circulation: process simulation and operation of an experimental setup  

Science Journals Connector (OSTI)

Simulation of the MTG process carried out in a fluidized bed reactor–regenerator system with catalyst circulation is studied by using the kinetic results obtained in an experimental unit. Data considered covered a wide range of operating conditions including temperature, space time and average residence times in both reactor and regenerator. This simulation is based on the use of adequate kinetic equations for the main MTG reaction, for the catalyst deactivation and for catalyst regeneration. In addition, a third stage in the process allowing for coke equilibration, prior to its combustion, is also included. Catalyst loss due to attrition has also been taken into account. An objective function based on relative production rate is optimized by changing systematically the process parameters such as temperature, space time and catalyst activity. Results are also validated in the experimental unit and demonstrate the simplicity of the reactor–regenerator system with catalyst circulation and the versatility of this configuration for carrying out the MTG process.

Ana G. Gayubo; Jose M. Ortega; Andres T. Aguayo; Jose M. Arandes; Javier Bilbao

2000-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

The physics of magnetic fusion reactors  

Science Journals Connector (OSTI)

During the past two decades there have been substantial advances in magnetic fusion research. On the experimental front, progress has been led by the mainline tokamaks, which have achieved reactor-level values of temperature and plasma pressure. Comparable progress, when allowance is made for their smaller programs, has been made in complementary configurations such as the stellarator, reversed-field pinch and field-reversed configuration. In this paper, the status of understanding of the physics of toroidal plasmas is reviewed. It is shown how the physics performance, constrained by technological and economic realities, determines the form of reference toroidal reactors. A comparative study of example reactors is not made, because the level of confidence in projections of their performance varies widely, reflecting the vastly different levels of support which each has received. Success with the tokamak has led to the initiation of the International Thermonuclear Experimental Reactor project. It is designed to produce 1500 MW of fusion power from a deuterium-tritium plasma for pulses of 1000 s or longer and to demonstrate the integration of the plasma and nuclear technologies needed for a demonstration reactor.

John Sheffield

1994-07-01T23:59:59.000Z

142

Metrology/viewing system for next generation fusion reactors  

SciTech Connect

Next generation fusion reactors require accurate measuring systems to verify sub-millimeter alignment of plasma-facing components in the reactor vessel. A metrology system capable of achieving such accuracy must be compatible with the vessel environment of high gamma radiation, high vacuum, elevated temperature, and magnetic field. This environment requires that the system must be remotely deployed. A coherent, frequency modulated laser radar system is being integrated with a remotely operated deployment system to meet these requirements. The metrology/viewing system consists of a compact laser transceiver optics module which is linked through fiber optics to the laser source and imaging units that are located outside of the harsh environment. The deployment mechanism is a telescopic-mast positioning system. This paper identifies the requirements for the International Thermonuclear Experimental Reactor metrology and viewing system, and describes a remotely operated precision ranging and surface mapping system.

Spampinato, P.T.; Barry, R.E.; Chesser, J.B.; Menon, M.M. [Oak Ridge National Lab., TN (United States); Dagher, M.A. [Boeing Rocketdyne Div., Canoga Park, CA (United States)

1997-02-01T23:59:59.000Z

143

Activation analysis of concrete and graphite in the experimental reactor RUS  

Science Journals Connector (OSTI)

......in the whole reactor, as a function...consistency and the reliability of the nuclear...for activation analysis. We believe...industrial nuclear reactors. INTRODUCTION...consistency and the reliability of the nuclear...for activation analysis. We believe...industrial nuclear reactors. | CEA Saclay......

M. Cometto; D. Ridikas; M. C. Aubert; F. Damoy; D. Ancius

2005-12-20T23:59:59.000Z

144

Probing thermonuclear supernova explosions with neutrinos  

E-Print Network (OSTI)

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.

A. Odrzywolek; T. Plewa

2011-03-27T23:59:59.000Z

145

Error analysis for resonant thermonuclear reaction rates  

Science Journals Connector (OSTI)

A detailed presentation is given of estimating uncertainties in thermonuclear reaction rates for stellar nucleosynthesis involving narrow resonances, starting from random errors in measured or calculated resonance and nuclear level properties. Special attention is given to statistical matters such as probability distributions, error propagation, and correlations between errors. Interpretation of resulting uncertainties in reaction rates and the distinction between symmetric and asymmetric errors are also discussed. Computing reaction rate uncertainties is described. We give examples from explosive nucleosynthesis by hydrogen burning on light nuclei.

William J. Thompson; C. Iliadis

1999-01-01T23:59:59.000Z

146

Atomic Physics and Thermonuclear Fusion Research  

Science Journals Connector (OSTI)

Presently thermonuclear fusion research is faced with a number of atomic and molecular physics problems depending on the type of high-temperature plasma investigated. The present article discusses some particular atomic physics aspects in connection with magnetically confined plasmas (Tokamaks, Stellarators): (1) rate equations for density, momentum and energy with application to plasmas; (2) initial phase of Tokamak plasmas; (3) influence of impurity radiation on operating conditions of fusion plasmas in general and on Tokamak plasmas in particular; (4) influence of atomic elementary reactions on thermodynamic plasma properties; (5) level structures of highly ionized atoms; (6) spectroscopic diagnostic problems.

H W Drawin

1981-01-01T23:59:59.000Z

147

The Fractional Kinetic Equation and Thermonuclear Functions  

E-Print Network (OSTI)

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.

H. J. Haubold; A. M. Mathai

2000-01-16T23:59:59.000Z

148

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

SciTech Connect

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.

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

2011-01-01T23:59:59.000Z

149

Decontamination and decommissioning of the Experimental Boiling Water Reactor (EBWR): Project final report, Argonne National Laboratory  

SciTech Connect

The Final Report for the Decontamination and Decommissioning (D&D) of the Argonne National Laboratory - East (ANL-E) Experimental Boiling Water Reactor (EBWR) facility contains the descriptions and evaluations of the activities and the results of the EBWR D&D project. It provides the following information: (1) An overall description of the ANL-E site and EBWR facility. (2) The history of the EBWR facility. (3) A description of the D&D activities conducted during the EBWR project. (4) A summary of the final status of the facility, including the final and confirmation surveys. (5) A summary of the final cost, schedule, and personnel exposure associated with the project, including a summary of the total waste generated. This project report covers the entire EBWR D&D project, from the initiation of Phase I activities to final project closeout. After the confirmation survey, the EBWR facility was released as a {open_quotes}Radiologically Controlled Area,{close_quotes} noting residual elevated activity remains in inaccessible areas. However, exposure levels in accessible areas are at background levels. Personnel working in accessible areas do not need Radiation Work Permits, radiation monitors, or other radiological controls. Planned use for the containment structure is as an interim transuranic waste storage facility (after conversion).

Fellhauer, C.R.; Boing, L.E. [Argonne National Lab., IL (United States); Aldana, J. [NES, Inc., Danbury, CT (United States)

1997-03-01T23:59:59.000Z

150

Cryogenic system component development for the fusion experimental reactor at JAERI  

SciTech Connect

The major objective of fusion R and D at the Japan Atomic Energy Research Institute (JAERI) is to construct the Fusion Experimental Reactor (FER) to follow JT-60. The construction of FER inevitably requires development of a large, reliable, and efficient helium liquefier/refrigerator and the more advanced cryogenic technology for cooling superconducting toroidal and poloidal coils. Typical characteristics required for the cryogenic system of FER are 10 to 20 kW at 4 K as one unit, reliability for > 8000 h, a stable pulsed heat load, and high-energy efficiency of > 1/500. In this cryogenic system, the major components such as the helium compressor, turbo-expander, cold circulation pump for supercritical helium, and cold compressor to reduce operating temperature below 4 K should be scaled up to a mass flow rate of > 1000 g/s. For this purpose, JAERI has developed cryogenics since 1980 in accordance with the development program in which the scaling up of the major components mentioned above are involved as well as cooling technology development.

Kato, T.; Kamiya, S.; Tada, E.; Hiyama, T.; Kawano, K.; Shimamoto, S.

1986-01-01T23:59:59.000Z

151

Oscillations During Thermonuclear X-ray Bursts  

E-Print Network (OSTI)

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.

Tod E. Strohmayer

2001-01-12T23:59:59.000Z

152

On the Stability of Thermonuclear Burning Fronts in Type Ia Supernovae  

Science Journals Connector (OSTI)

The propagation of cellularly stabilized thermonuclear flames is investigated by means of numerical ... fuel flows. Our simulations indicate that in thermonuclear supernova explosions stable cellular flames devel...

F.K. Röpke; W. Hillebrandt

2005-01-01T23:59:59.000Z

153

E-Print Network 3.0 - astrophysical thermonuclear reactions Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

thermonuclear reactions Search Powered by Explorit Topic List Advanced Search Sample search results for: astrophysical thermonuclear reactions Page: << < 1 2 3 4 5 > >> 1 Workshop...

154

E-Print Network 3.0 - alamos thermonuclear weapon Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

thermonuclear weapon Search Powered by Explorit Topic List Advanced Search Sample search results for: alamos thermonuclear weapon Page: << < 1 2 3 4 5 > >> 1 Dr. Lodwick's research...

155

E-Print Network 3.0 - atypical thermonuclear supernovae Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

thermonuclear supernovae Search Powered by Explorit Topic List Advanced Search Sample search results for: atypical thermonuclear supernovae Page: << < 1 2 3 4 5 > >> 1 Supernova...

156

agesta reactor: Topics by E-print Network  

NLE Websites -- All DOE Office Websites (Extended Search)

of a severe unprotected (more) DeWitte, Jacob D. (Jacob Dominic) 2011-01-01 16 Thermonuclear Reflect AB-Reactor Physics (arXiv) Summary: The author offers a new kind of...

157

Experimental and modeling study of catalytic steam reforming of methane mixture with propylene in a packed bed reactor  

Science Journals Connector (OSTI)

Abstract Producer gas from biomass gasification contains mainly hydrogen, carbon dioxide, carbon monoxide, methane and some other low molecular hydrocarbons like propylene. This paper reports mathematical simulation and experimental study of steam reforming of methane mixture with propylene in a packed bed reactor filled with nickel based catalysts. Due to the high heat input through the reformer tube wall and the endothermic reforming reactions, a two-dimensional pseudo-heterogeneous model that takes into account the diffusion reaction phenomena in gas phase as well as inside the catalyst particles has been used to represent temperature distribution and species concentration within the reactor. Steam reforming of propylene is faster and more selective than methane and it is shown that addition of propylene to the methane steam mixture reduces the conversion of methane. The obtained results play a key role in optimization and design of a commercial reactor.

Parham Sadooghi; Reinhard Rauch

2014-01-01T23:59:59.000Z

158

Experimental method for reactor-noise measurements of effective beta. [LMFBR  

SciTech Connect

A variance-to-mean noise technique, modified to eliminate systematic errors from drifting of reactor power, has been used to infer integral values of effective beta for uranium and plutonium fueled fast reactor modk-ups. The measurement technique, including corrections for a finite detector-electrometer time response, is described together with preliminary beta measurement results.

Bennett, E.F.

1981-09-01T23:59:59.000Z

159

INERTIAL FUSION DRIVEN BY INTENSE HEAVY-ION BEAMS  

E-Print Network (OSTI)

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

Sharp, W. M.

2011-01-01T23:59:59.000Z

160

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

SciTech Connect

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.

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

2008-07-08T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

The physics of antimatter induced fusion and thermonuclear explosions  

E-Print Network (OSTI)

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.

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

1987-01-01T23:59:59.000Z

162

Experimental verification of a mathematical model of a semibatch biological reactor  

E-Print Network (OSTI)

EXPERIIMNTAL VERIFICATION OF A I ST~ATICAL MODEL OF A SEMIBATCN BIOLOGICAL REACTOR A Thesis THOMAS PATRICK FOX Submitted. to the Graduate College of Texas AA? University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE December 1971 Major Subject: Civil Engineering EXPERIIIZRTAL VERIFICATION OF A MATHEl'ATICAL MODEL OF A SEMIBATCH BIOLOGICAL REACTOR A Thesis THOMAS PATRICK FOX Approved as to style and content by: (Chairman of Committee) (Head...

Fox, Thomas Patrick

2012-06-07T23:59:59.000Z

163

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

E-Print Network (OSTI)

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

Y. E. Kim

2008-01-01T23:59:59.000Z

164

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

E-Print Network (OSTI)

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

H. J. Haubold

165

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

E-Print Network (OSTI)

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

Carmignani, B

2005-01-01T23:59:59.000Z

166

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

E-Print Network (OSTI)

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.

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

167

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

E-Print Network (OSTI)

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.

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

1998-06-05T23:59:59.000Z

168

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

E-Print Network (OSTI)

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.

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

169

Atomic Collision Processes in Magnetic Confinement Controlled Thermonuclear Fusion Research  

Science Journals Connector (OSTI)

This NATO Advanced Study Institute is concerned with atomic and molecular processes in controlled thermonuclear fusion research. Most of our attention will be ... and planned tokamaks, since this approach to fusion

M. R. C. McDowell

1980-01-01T23:59:59.000Z

170

AEC Policy and Action Paper on Controlled Thermonuclear Research  

Science Journals Connector (OSTI)

This report was prepared in late 1965 at the request of the U.S. House-Senate Joint Committee on Atomic Energy (JCAE) to review its program on controlled thermonuclear research (CTR), now called just “fusion ener...

Amasa S. Bishop; Stephen O. Dean; Richard F. Post

2011-06-01T23:59:59.000Z

171

Are Cataclysmic Variables the Progenitors of Thermonuclear Supernovae?  

Science Journals Connector (OSTI)

In 1973, Whelan and Iben suggested that binary stars, similar in structure to Cataclysmic Variables but not called that by them, were the progenitors of SN Ia’s. Their evidence included the fact that thermonuclear

Sumner Starrfield

2003-01-01T23:59:59.000Z

172

Subchannel Thermal-Hydraulic Experimental Program (STEP). Volume 1. Mixing in a pressurized water reactor (PWR) rod bundle. Final report  

SciTech Connect

This volume describes an experiment that was performed to determine the mixing characteristics of a pressurized water reactor (PWR) rod bundle. The objective of this project was to improve the subchannel computer code models of the reactor core. The experimental technique was isokinetic subchannel withdrawal of the entire flow from two sample subchannels. Once withdrawn, the sample fluid was condensed and its enthalpy was measured by regenerative heat exchange calorimetry. The test bundle was a 4 x 6 electrically heated array with a 50% power upset. The COBRA IIIC code was used to model the experiment and to determine the value of the thermal mixing coefficient, ..beta.., that was necessary to predict the measured results. Both single- and two-phase data were obtained over a range of PWR operating conditions. The results indicate that both single- and two-phase mixing is small. The COBRA model predicts the enthalpy data using a turbulent mixing coefficient, ..beta.. approx. = 0.002.

Barber, A.R.; Zielke, L.A.

1980-08-01T23:59:59.000Z

173

Study of Thermonuclear Alfven Instabilities in Next Step Burning Plasma Experiments  

SciTech Connect

A study is presented for the stability of alpha-particle driven shear Alfven Eigenmodes (AE) for the normal parameters of the three major burning plasma proposals, ITER (International Thermonuclear Experimental Reactor), FIRE (Fusion Ignition Research Experiment), and IGNITOR (Ignited Torus). A study of the JET (Joint European Torus) plasma, where fusion alphas were generated in tritium experiments, is also included to attempt experimental validation of the numerical predictions. An analytic assessment of Toroidal AE (TAE) stability is first presented, where the alpha particle beta due to the fusion reaction rate and electron drag is simply and accurately estimated in 7-20 keV plasma temperature regime. In this assessment the hot particle drive is balanced against ion-Landau damping of the background deuterons and electron collision effects and stability boundaries are determined. Then two numerical studies of AE instability are presented. In one the High-n stability code HINST is used . This code is capable of predicting instabilities of low and moderately high frequency Alfven modes. HINST computes the non-perturbative solution of the Alfven eigenmodes including effects of ion finite Larmor radius, orbit width, trapped electrons etc. The stability calculations are repeated using the global code NOVAK. We show that for these tokamaks the spectrum of the least stable AE modes are TAE that appear at medium-/high-n numbers. In HINST TAEs are locally unstable due to the alphas pressure gradient in all the devices under the consideration except IGNITOR. However, NOVAK calculations show that the global mode structure enhances the damping mechanisms and produces stability in all configurations considered here. A serious question remains whether the perturbation theory used in NOVAK overestimates the stability predictions, so that it is premature to conclude that the nominal operation of all three proposals are stable to AEs. In addition NBI ions produce a strong stabilizing effect for JET. However, in ITER the beam energies needed to penetrate to the core must be high so that a diamagnetic drift frequency comparable to that of the alpha particles is produced by the beam ions which induces a destabilizing effect.

N.N. Gorelenkov; H.L. Berk; R. Budny; C.Z. Cheng; G.-Y. Fu; W.W. Heidbrink; G. Kramer; D. Meade; and R. Nazikian

2002-07-02T23:59:59.000Z

174

Thermonuclear supernova simulations with stochastic ignition  

E-Print Network (OSTI)

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.

W. Schmidt; J. C. Niemeyer

2005-10-14T23:59:59.000Z

175

Plasma and the Controlled Thermonuclear Reaction  

Science Journals Connector (OSTI)

...The gas heated by the neutrons passes through a gas turbine (5) where it adiabatically ex-pands. Next it...connecting the container of the reactor with the gas turbine; 5, gas turbine; 6, isothermal compressor; 7, cooling water...

P. L. Kapitza

1979-09-07T23:59:59.000Z

176

JET deuterium: tritium results and their implications  

Science Journals Connector (OSTI)

...ignition and thermonuclear burn will occur in ITER and a fusion reactor. magnetic...state) and fusion duration...International Thermonuclear Experimental...ignition and thermonuclear burn will occur in ITER and a fusion reactor. Keywords...

1999-01-01T23:59:59.000Z

177

History of the approach to ignition  

Science Journals Connector (OSTI)

...International Thermonuclear Experimental Reactor...recommended. plasma|fusion|tokamak|ignition...density plasma to thermonuclear temperatures...in the quest for fusion power. Such an...temperatures of thermonuclear interest, this...for an acceptable fusion reactor. By a...

1999-01-01T23:59:59.000Z

178

Experimental investigations on reactor scale-up and optimisation of product quality in pyrolysis of shredder waste  

Science Journals Connector (OSTI)

Shredder waste is the light fraction separated from automotive shredder scrap by air classifiers and contains mainly plastics. The present work focuses on pyrolysis of shredder waste as a possible way for chemical recycling of plastic wastes and deals with the technical requirements for an industrial application. Pyrolysis experiments have been conducted in two different laboratory reactors at high and low heating rates in order to determine product yields. The investigations lead to a more detailed understanding of the primary and secondary chemical reactions involved and the influence of the main process parameters. The results indicate clearly that appropriate conditions for secondary reactions are decisive criteria to attain the desired optimum product quality, e.g. a more homogeneous product spectrum with enhanced yields of light aromatics. Catalysts can improve cracking and isomerisation as well as chlorine removal. The derived criteria for reactor design and process development have shown heating rate, residence time, and temperature to be decisive parameters in scale-up considerations and in extrapolation of laboratory-scale experimental results. It can be concluded that reactors with extended residence time like, for example, a rotary kiln in combination with a subsequent solid catalyst bed for refining of the volatiles can provide promising process solutions in a pyrolytic recycling concept for plastic wastes like automotive shredder waste.

Ch Pasel; W Wanzl

2003-01-01T23:59:59.000Z

179

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

SciTech Connect

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.

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

2014-08-20T23:59:59.000Z

180

Experimental evaluation of gamma fluence-rate predictions from Argon-41 releases to the atmosphere over a nuclear research reactor site  

Science Journals Connector (OSTI)

......radiation experimental dataset has been subsequently...reactor at the Belgium Nuclear Research Center...measurements. The dataset obtained may also...3, 4) used for nuclear emergency preparedness...radiation experimental dataset has been subsequently...RIMPUFF. | Belgian Nuclear Research Center......

Carlos Rojas-Palma; Helle Karina Aage; Poul Astrup; Kim Bargholz; Martin Drews; Hans E. Jørgensen; Uffe Korsbech; Bent Lauritzen; Torben Mikkelsen; Søren Thykier-Nielsen; Raf Van Ammel

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

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)

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...

Vaghetto, Rodolfo

2012-07-16T23:59:59.000Z

182

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

SciTech Connect

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.

Rodolfo Vaghetto; Luigi Capone; Yassin A. Hassan

2011-05-31T23:59:59.000Z

183

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

E-Print Network (OSTI)

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.

P. Mohr; R. Longland; C. Iliadis

2014-12-09T23:59:59.000Z

184

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

E-Print Network (OSTI)

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.

P. Mohr; R. Longland; C. Iliadis

2014-12-14T23:59:59.000Z

185

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

E-Print Network (OSTI)

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.

Mohr, P; Iliadis, C

2014-01-01T23:59:59.000Z

186

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

E-Print Network (OSTI)

shaft. With the impeller in place and rotating, gas was drawn into the top port and ejected at the impeller mount. The reactor pressure was monitored via the transducer port. The transducer was a Viatran Pressure Transducer, model 103. The liquid...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...

Hess, Richard Kenneth

2012-06-07T23:59:59.000Z

187

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

E-Print Network (OSTI)

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 ...

Apo, Daniel Jolomi

2012-01-01T23:59:59.000Z

188

Thermonuclear Fusion with the Sheared Flow Stabilized Z-Pinch  

E-Print Network (OSTI)

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.

Winterberg, F

2008-01-01T23:59:59.000Z

189

Thermonuclear Supernovae: Simulations of the Deflagration Stage and Their Implications  

E-Print Network (OSTI)

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.

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

2002-12-03T23:59:59.000Z

190

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

E-Print Network (OSTI)

1 A time-delay approach for the modeling and control of plasma instabilities in thermonuclear for thermonuclear fusion plasmas. Indeed, advanced plasma confinement scenarios, such as the ones considered

Sipahi, Rifat

191

Experimental determination of residual stress by neutron diffraction in a boiling water reactor core shroud  

SciTech Connect

Residual strains in a 51 mm (2-inch) thick 304L stainless steel plate have been measured by neutron diffraction and interpreted in terms of residual stress. The plate, measuring (300 mm) in area, was removed from a 6m (20-ft.) diameter unirradiated boiling water reactor core shroud, and included a multiple-pass horizontal weld which joined two of the cylindrical shells which comprise the core shroud. Residual stress mapping was undertaken in the heat affected zone, concentrating on the outside half of the plate thickness. Variations in residual stresses with location appeared consistent with trends expected from finite element calculations, considering that a large fraction of the residual hoop stress was released upon removal of the plate from the core shroud cylinder.

Payzant, A.; Spooner, S.; Zhu, Xiaojing; Hubbard, C.R. [and others

1996-06-01T23:59:59.000Z

192

Thermonuclear explosions of Chandrasekhar-mass C+O white dwarfs  

E-Print Network (OSTI)

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

M. Reinecke; W. Hillebrandt

1998-01-01T23:59:59.000Z

193

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

194

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

195

Magnetic Braids Anthony Yeates  

E-Print Network (OSTI)

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

Dundee, University of

196

Treating Unresolvable Flame Physics in Simulations of Thermonuclear Supernovae  

Science Journals Connector (OSTI)

Due to the small width of the subsonic burning front (flame) in thermonuclear supernovae, micrometers to centimeters, and the influence of turbulence, which adds structure to this front on a broad range of scales, it won't be possible in the foreseeable ... Keywords: Computational astrophysics, combustion, turbulence

Dean M. Townsley

2009-03-01T23:59:59.000Z

197

The LOFT perspective on neutron star thermonuclear bursts  

E-Print Network (OSTI)

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.

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

198

Millisecond oscillations during thermonuclear X-ray bursts  

E-Print Network (OSTI)

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. ...

Muno, Michael Patrick, 1975-

2002-01-01T23:59:59.000Z

199

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

SciTech Connect

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.

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

2011-12-29T23:59:59.000Z

200

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

E-Print Network (OSTI)

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.

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

2002-06-03T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Strong plasma screening in thermonuclear reactions: Electron drop model  

Science Journals Connector (OSTI)

We analyze enhancement of thermonuclear fusion reactions due to strong plasma screening in dense matter using a simple electron drop model. In the model we assume 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 the 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 a 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.

P. A. Kravchuk and D. G. Yakovlev

2014-01-09T23:59:59.000Z

202

Strong plasma screening in thermonuclear reactions: Electron drop model  

E-Print Network (OSTI)

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.

Kravchuk, P A

2014-01-01T23:59:59.000Z

203

Strong plasma screening in thermonuclear reactions: Electron drop model  

E-Print Network (OSTI)

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.

P. A. Kravchuk; D. G. Yakovlev

2014-01-11T23:59:59.000Z

204

Relativistic outflow from two thermonuclear shell flashes on neutron stars  

E-Print Network (OSTI)

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 $^...

Zand, Jean in 't; Cavecchi, Yuri

2014-01-01T23:59:59.000Z

205

Method of achieving the controlled release of thermonuclear energy  

DOE Patents (OSTI)

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.

Brueckner, Keith A. (Ann Arbor, MI)

1986-01-01T23:59:59.000Z

206

Experimental and Modeling Studies of the Methane Steam Reforming Reaction at High Pressure in a Ceramic Membrane Reactor.  

E-Print Network (OSTI)

??This dissertation describes the preparation of a novel inorganic membrane for hydrogen permeation and its application in a membrane reactor for the study of the… (more)

Hacarlioglu, Pelin

2007-01-01T23:59:59.000Z

207

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

SciTech Connect

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.

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

208

Isotope correlations for determining the isotopic composition of plutonium produced in research and power reactors using the experimental data obtained by alpha and mass spectrometry  

Science Journals Connector (OSTI)

Correlations have been developed for obtaining the isotopic composition of Pu produced in Indian research (CIRUS, DHRUVA) and power (PHWR) reactors. The experimental data obtained on 238Pu/(239Pu + 240Pu) alpha activity ratio using alpha spectrometry and on 240Pu/239Pu, 241Pu/239Pu, 242Pu/239Pu atom ratios by thermal ionisation mass spectrometry were used for developing isotope correlations.

S.K. Aggarwal; D. Alamelu

2005-01-01T23:59:59.000Z

209

Closed-form evaluation and approximation considerations of the non-resonant thermonuclear reaction rate  

Science Journals Connector (OSTI)

By use of a highly efficient theory of generalized hypergeometric functions, we show that the non-resonant thermonuclear reaction rate can be evaluated in closed...

H. J. Haubold; R. W. John

1981-04-01T23:59:59.000Z

210

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

E-Print Network (OSTI)

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.

H. J. Haubold; D. Kumar

2007-08-16T23:59:59.000Z

211

One-flow feed divided electrochemical reactor for indirect electrolytic production of hypochlorite from brine for swimming pool treatment-experimental and theoretical optimization  

Science Journals Connector (OSTI)

Abstract A ‘two-compartment’ asymmetric electrochemical reactor, operating without electrodes polarity inversion, was designed and optimized for the chlorination of swimming pools. Gaseous chlorine, produced at the anode and absorbed in the alkalinized catholyte, provides the hypochlorite solution. Empiric equations providing the chloride concentration dependence on the initial current density magnitude were established. Experimental optimization of the effect of the various operating parameters allows a chloride conversion close to 50% with faradic yields higher than 80%, and a chlorine production of 1 kmol/day/m2 to be achieved. Macroscopic mass balance, was performed and the obtained theoretical results correlate with the experimental ones ( X theor . Cl - - X exper . Cl -  < 10%).

T. Tzedakis; Y. Assouan

2014-01-01T23:59:59.000Z

212

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

213

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

214

Thermonuclear Explosions of Chandrasekhar-Mass White Dwarfs  

E-Print Network (OSTI)

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.

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

2000-05-16T23:59:59.000Z

215

The computational-and-experimental investigation into the head-flow characteristic of the two-stage ejector for the emergency core cooling system of the NPP with a water-moderated water-cooled power reactor  

Science Journals Connector (OSTI)

The results of the computational-and-experimental investigation into the two-stage ejector for the emergency cooling system of the core of the water-moderated water-cooled power reactor. The results of experiment...

Yu. V. Parfenov

2013-09-01T23:59:59.000Z

216

E-Print Network 3.0 - advanced fusion material Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Physics and Fusion 5 Fusion Energy Program Presentation to Summary: International Thermonuclear Experimental Reactor Plasma Technologies Fusion Technologies Advanced Materials......

217

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

218

E-Print Network 3.0 - advanced tokamak plasmas Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Physics and Fusion 15 Fusion Energy Program Presentation to Summary: International Thermonuclear Experimental Reactor Plasma Technologies Fusion Technologies Advanced Materials......

219

Annual Performance Report and Plan FY12 FY13 FY14  

Energy Savers (EERE)

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

220

E-Print Network 3.0 - advanced deuterium fusion Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Physics and Fusion 2 Fusion Energy Program Presentation to Summary: International Thermonuclear Experimental Reactor Plasma Technologies Fusion Technologies Advanced Materials......

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Faint Thermonuclear Supernovae from AM Canum Venaticorum Binaries  

Science Journals Connector (OSTI)

Helium that accretes onto a carbon/oxygen white dwarf in 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, > 10-7 M? yr-1), the flashes are weak and likely lead to the helium equivalent of classical nova outbursts. However, as the orbit widens and 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 M?. The high pressures of these last flashes allow the burning to produce the radioactive elements 48Cr, 52Fe, and 56Ni that power a faint (MV = -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 1011 M? 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 1000 per year.

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

2007-01-01T23:59:59.000Z

222

Simulations of Turbulent Thermonuclear Burning in Type Ia Supernovae  

E-Print Network (OSTI)

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.

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

2004-05-11T23:59:59.000Z

223

Cosmic and Galactic Neutrino Backgrounds from Thermonuclear Sources  

E-Print Network (OSTI)

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.

Cristiano Porciani; Silvia Petroni; Giovanni Fiorentini

2003-11-20T23:59:59.000Z

224

Faint Thermonuclear Supernovae from AM Canum Venaticorum Binaries  

E-Print Network (OSTI)

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.

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

2007-05-06T23:59:59.000Z

225

Thermonuclear supernova models, and observations of Type Ia supernovae  

E-Print Network (OSTI)

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.

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

2004-12-07T23:59:59.000Z

226

On the Evolution of Thermonuclear Flames on Large Scales  

E-Print Network (OSTI)

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.

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

2006-10-05T23:59:59.000Z

227

Astrophysical Thermonuclear Functions for Boltzmann-Gibbs Statistics and Tsallis Statistics  

E-Print Network (OSTI)

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.

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

2004-06-22T23:59:59.000Z

228

Current state, problems, and prospects of thermonuclear facilities based on the magneto-inertial confinement of hot plasma  

Science Journals Connector (OSTI)

Magneto-inertial fusion (MIF) is an original technique of inertial thermonuclear fusion, where spherical and cylindrical gas or plasma...

S. V. Ryzhkov

2014-05-01T23:59:59.000Z

229

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

E-Print Network (OSTI)

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

Rosswog, Stephan

230

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

E-Print Network (OSTI)

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

Paris-Sud XI, Université de

231

Influence of gas composition on wafer temperature in a tungsten chemical vapor deposition reactor: Experimental measurements, model  

E-Print Network (OSTI)

Influence of gas composition on wafer temperature in a tungsten chemical vapor deposition reactor-wafer, lamp-heated chemical vapor deposition system were used to study the wafer temperature response to gas composition. A physically based simulation procedure for the process gas and wafer temperature was developed

Rubloff, Gary W.

232

On the Evolution of Thermonuclear Flames on Large Scales  

Science Journals Connector (OSTI)

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 in 1995. The mechanism of vorticity production and the interaction between vortices and the flame surface are discussed. Previously observed periodic behavior of the flame evolution is reproduced and is found to be caused by the turnover of the largest eddies. The characteristic timescales are found to be similar to the turnover time of these eddies. Relations between flame surface creation and destruction processes and basic characteristics of the flow are discussed. We find that the flame surface creation strength is associated with the Rayleigh-Taylor timescale. Also, in fully developed turbulence, the flame surface destruction strength scales as 1/L3, where L is the turbulent driving scale. The results of our investigation provide support for Khokhlov's self-regulating model of turbulent thermonuclear flames. Based on these results, one can revise and extend the original model. The revision uses a local description of the flame surface enhancement and the evolution of the flame surface since the onset of turbulence, rendering it free from the assumption of an instantaneous steady state of turbulence. This new model can be applied to the initial transient phase of the flame evolution, where the self-regulation mechanism yet to be fully established. Details of this new model will be presented in a forthcoming paper.

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

2007-01-01T23:59:59.000Z

233

Screening in Thermonuclear Reaction Rates in the Sun  

E-Print Network (OSTI)

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.

Andrei V. Gruzinov; John N. Bahcall

1998-01-20T23:59:59.000Z

234

The Periods Discovered by RXTE in Thermonuclear Flash Bursts  

E-Print Network (OSTI)

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.

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

1998-01-23T23:59:59.000Z

235

On the stability of thermonuclear shell sources in stars  

E-Print Network (OSTI)

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.

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

2004-06-07T23:59:59.000Z

236

Measurement of neutron capture on 50Ti at thermonuclear energies  

E-Print Network (OSTI)

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.

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

1999-07-28T23:59:59.000Z

237

Detonating Failed Deflagration Model of Thermonuclear Supernovae I. Explosion Dynamics  

E-Print Network (OSTI)

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.

Tomasz Plewa

2006-11-24T23:59:59.000Z

238

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

E-Print Network (OSTI)

. The power to the water heater is controlled by a Fisher Proportional Temperature Control (Catalog P3 TENPERATURE CONTROLLER CONSTANT TENPERATURE BATH P2 CHILLER ELECTRICAL HEATER Figure 3. Schematic of Reactor Temperature Control System 20... successful column; i, e, , extremely high pressure drops and low plate counts were observed in these columns. As a last measure, the gel was stirred in a hot, concen- trated sodium hydroxide solution (approximately pH 13) for ten hours. The excess sodium...

Cox, James Harvey

2012-06-07T23:59:59.000Z

239

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

SciTech Connect

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.

Simos, N.

2011-05-01T23:59:59.000Z

240

Alerting Humanitarians to Emergencies TOKYO, March 9 (Reuters) -Japan warned the European Union on Wednesday  

E-Print Network (OSTI)

to construct the first thermonuclear reactor -- the European Union, Japan, China, the United States, Russia Thermonuclear Experimental Reactor (ITER) is forecast to cost some 4.6 billion euros ($6.14 billion) over 10

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Plasma-materials interactions and impurity control in magnetically confined thermonuclear fusion machines  

Science Journals Connector (OSTI)

Progress achieved in plasma heating and magnetic confinement during the past decade has brought to the fore a number of problems which have to be solved if controlled thermonuclear fusion is to become an economic...

Dieter M. Gruen; Stanislav Vep?ek; Randy B. Wright

1980-01-01T23:59:59.000Z

242

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

E-Print Network (OSTI)

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) ...

in ’t Zand, J. J. M.

243

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

E-Print Network (OSTI)

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...

Keek, L; Heger, A

2014-01-01T23:59:59.000Z

244

Thermonuclear X-ray Bursts: Theory vs. Observations  

E-Print Network (OSTI)

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.

Andrew Cumming

2003-11-18T23:59:59.000Z

245

The NACRE Thermonuclear Reaction Compilation and Big Bang Nucleosynthesis  

E-Print Network (OSTI)

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.

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

2001-05-17T23:59:59.000Z

246

The cooling rate of neutron stars after thermonuclear shell flashes  

E-Print Network (OSTI)

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...

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

2013-01-01T23:59:59.000Z

247

DOE LAUNCHES R&D BLUEPRINT  

Science Journals Connector (OSTI)

The highest priority item is the International Thermonuclear Experimental Reactor (ITER), a $5 billion fusion reactor being developed by an international consortium of countries. ...

JEFF JOHNSON

2003-11-17T23:59:59.000Z

248

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

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.

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

2006-10-20T23:59:59.000Z

249

Laser-fusion targets for reactors  

DOE Patents (OSTI)

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.

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

1987-01-01T23:59:59.000Z

250

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

E-Print Network (OSTI)

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.

Anuj Parikh; Jordi Jose; Fermin Moreno; Christian Iliadis

2008-06-18T23:59:59.000Z

251

Nuclear Reactor (atomic reactor)  

Science Journals Connector (OSTI)

A nuclear reactor splits Uranium or Plutonium nuclei, and the...235 is fissionable but more than 99% of the naturally occurring Uranium is U238 that makes enrichment mandatory. In some reactors U238 and Thorium23...

2008-01-01T23:59:59.000Z

252

Govt may concede ITER site to France The Yomiuri Shimbun  

E-Print Network (OSTI)

the building of the planned International Thermonuclear Experimental Reactor in another country providing Japan is an experimental facility of thermonuclear fusion, at which nuclear fusion reactions that occur on the sun

253

Astrophysical S-factors of proton radiative capture for thermonuclear reactions  

E-Print Network (OSTI)

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.

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

2011-12-09T23:59:59.000Z

254

Super-Eddington Fluxes During Thermonuclear X-ray Bursts  

Science Journals Connector (OSTI)

It has been known for nearly three decades that the energy spectra of thermonuclear X-ray bursts are often well fit by Planck functions with temperatures so high that they imply a super-Eddington radiative flux at the emitting surface, even during portions of bursts when there is no evidence of photospheric radius expansion. This apparent inconsistency is usually set aside by assuming that the flux is actually sub-Eddington and that the fitted temperature is so high because the spectrum has been distorted by the energy-dependent opacity of the atmosphere. Here we show that the spectra predicted by currently available conventional atmosphere models appear incompatible with the highest precision measurements of burst spectra made using the Rossi X-ray Timing Explorer, such as during the 4U 1820–30 superburst and a long burst from GX 17+2. In contrast, these measurements are well fit by Bose-Einstein spectra with high temperatures and modest chemical potentials. Such spectra are very similar to Planck spectra. They imply surface radiative fluxes more than a factor of 3 larger than the Eddington flux. We find that segments of many other bursts from many sources are well fit by similar Bose-Einstein spectra, suggesting that the radiative flux at the emitting surface also exceeds the Eddington flux during these segments. We suggest that burst spectra can closely approximate Bose-Einstein spectra and have fluxes that exceed the Eddington flux because they are formed by Comptonization in an extended, low-density radiating gas supported by the outward radiation force and confined by a tangled magnetic field.

Stratos Boutloukos; M. Coleman Miller; Frederick K. Lamb

2010-01-01T23:59:59.000Z

255

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

E-Print Network (OSTI)

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...

Wu, Huali

2013-08-08T23:59:59.000Z

256

The Fast-spectrum Transmutation Experimental Facility FASTEF: Main design achievements (part 2: Reactor building design and plant layout) within the FP7-CDT collaborative project of the European Commission  

SciTech Connect

MYRRHA (Multi-purpose hybrid Research Reactor for High-tech Applications) is the flexible experimental accelerator-driven system (ADS) in development at SCK-CEN in replacement of its material testing reactor BR2. SCK-CEN in association with 17 European partners from industry, research centres and academia, responded to the FP7 (Seventh Framework Programme) call from the European Commission to establish a Central Design Team (CDT) for the design of a Fast Spectrum Transmutation Experimental Facility (FASTEF) able to demonstrate efficient transmutation and associated technology through a system working in subcritical and/or critical mode. The project has started on April 01, 2009 for a period of three years. In this paper, we present the latest concept of the reactor building and the plant layout. The FASTEF facility has evolved quite a lot since the intermediate reporting done at the ICAPP'10 and ICAPP'11 conferences 1,2. Many iterations have been performed to take into account the safety requirements. The present configuration enables an easy operation and maintenance of the facility, including the possibility to change large components of the reactor. In a companion paper 3, we present the latest configuration of the reactor core and primary system. (authors)

De Bruyn, D.; Engelen, J. [Belgian Nuclear Research Centre SCK CEN, Boeretang 200, 2400 Mol (Belgium); Ortega, A.; Aguado, M. P. [Empresarios Agrupados A.I.E., Magallanes 3, 28015 Madrid (Spain)

2012-07-01T23:59:59.000Z

257

Laser-driven acceleration of a dense matter up to 'thermonuclear' velocities  

Science Journals Connector (OSTI)

The results of theoretical studies and numerical simulations of laser-driven acceleration of a flat foil up to ultrahigh velocity of the order of 1000?km?s?1, which corresponds to the achievement of thermonuclear temperatures due to kinetic energy transition into thermal energy at an inelastic impact, are reported. The behavior of a foil accelerated to such high velocities, in particular, the distribution of foil density, which defines thermonuclear reaction intensity, has been studied. The calculation results are compared with the results of the experiments performed on the Gekko/HIPER laser, where a laser-driven projectile achieved record-breaking velocity. The laser pulse and foil parameters responsible for acceleration of the projectile up to 'thermonuclear' velocities in a dense state have been determined.

S Yu Gus'kov; H Azechi; N N Demchenko; V V Demchenko; I Ya Doskoch; M Murakami; H Nagatomo; V B Rozanov; S Sakaiya; R V Stepanov; N V Zmitrenko

2007-01-01T23:59:59.000Z

258

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

259

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

260

On the Stability of Thermonuclear Burning Fronts in Type Ia Supernovae  

E-Print Network (OSTI)

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.

F. K. Roepke; W. Hillebrandt

2004-04-26T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Puzzling thermonuclear burst behaviour from the transient low-mass X-ray binary IGR J17473–2721  

Science Journals Connector (OSTI)

......hereafter G08]. Only a few observations of thermonuclear flashes occurring before the start of...bursts with the energy released by the thermonuclear bursts. Their ratio is the alpha parameter...superburst or the onset of a stable He fusion process. Again, it is interesting......

J. Chenevez; D. Altamirano; D. K. Galloway; J. J. M. in 't Zand; E. Kuulkers; N. Degenaar; M. Falanga; E. Del Monte; Y. Evangelista; M. Feroci; E. Costa

2011-01-01T23:59:59.000Z

262

Potential and desire for HTS application in thermonuclear fusion  

Science Journals Connector (OSTI)

Superconducting magnets are stringent for fusion reactors with magnetic confinement to provide an economic energy balance. Large-scale development programmes have been executed worldwide to achieve in time the needed technology. The ultimate result of this effort, so far, is the ITER magnet system with the most sophisticated LTS. However, if one thinks about the design of a fusion DEMO and later reactors, the option of HTS must be considered seriously in view of the potential advantages of these conductors concerning higher operation temperature, temperature margin, high field properties and cryogenic power saving. Extrapolating from the long period needed for the ITER conductor development, it is time now to start with HTS development for fusion reactors to be able to decide their applicability. It is still a long way for the HTS to become comparable with LTS, however, continuous progress can be seen. Beside the large confinement magnets, HTS will also be of advantage for current leads, bus bars and gyrotron magnets. The state of the art of HTS is such, that already now such components can be constructed with HTS.

P. Komarek

2006-01-01T23:59:59.000Z

263

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)

effect on stellar thermonuclear fusion Alexander Y. Potekhin1,2 and Gilles Chabrier2,3 1 Ioffe Physical thermonuclear reactions for various stellar objects, namely in the liquid envelopes of neutron stars. In addition, we examine some recent unconventional theo- retical results on stellar thermonuclear fusions

264

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)

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

Boal, David

265

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)

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

Miller, Cole

266

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

E-Print Network (OSTI)

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.

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

267

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

E-Print Network (OSTI)

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 ...

Linares, M.

268

Results from D—T experiments on TFTR and implications for achieving an ignited plasma  

Science Journals Connector (OSTI)

...significant bursts of fusion energy per pulse. This...of the International Thermonuclear Experimental Reactor...Texas, Institute for Fusion Studies, Austin, Texas...Institute of Innovative and Thermonuclear Research, Moscow...National Institute for Fusion Science, Nagoya, Japan...

1999-01-01T23:59:59.000Z

269

Profile of Keith Moffatt  

Science Journals Connector (OSTI)

...before a major experiment carried out at the International Thermonuclear Experimental Reactor site in Cadarache, France confirmed...work on magnetic relaxation, which has implications for thermonuclear fusion devices. Similar research describes the evolution...

Farooq Ahmed

2014-01-01T23:59:59.000Z

270

Physics design of a 100 keV acceleration grid system for the diagnostic neutral beam for international tokamak experimental reactor  

SciTech Connect

This paper describes the physics design of a 100 keV, 60 A H{sup -} accelerator for the diagnostic neutral beam (DNB) for international tokamak experimental reactor (ITER). The accelerator is a three grid system comprising of 1280 apertures, grouped in 16 groups with 80 apertures per beam group. Several computer codes have been used to optimize the design which follows the same philosophy as the ITER Design Description Document (DDD) 5.3 and the 1 MeV heating and current drive beam line [R. Hemsworth, H. Decamps, J. Graceffa, B. Schunke, M. Tanaka, M. Dremel, A. Tanga, H. P. L. De Esch, F. Geli, J. Milnes, T. Inoue, D. Marcuzzi, P. Sonato, and P. Zaccaria, Nucl. Fusion 49, 045006 (2009)]. The aperture shapes, intergrid distances, and the extractor voltage have been optimized to minimize the beamlet divergence. To suppress the acceleration of coextracted electrons, permanent magnets have been incorporated in the extraction grid, downstream of the cooling water channels. The electron power loads on the extractor and the grounded grids have been calculated assuming 1 coextracted electron per ion. The beamlet divergence is calculated to be 4 mrad. At present the design for the filter field of the RF based ion sources for ITER is not fixed, therefore a few configurations of the same have been considered. Their effect on the transmission of the electrons and beams through the accelerator has been studied. The OPERA-3D code has been used to estimate the aperture offset steering constant of the grounded grid and the extraction grid, the space charge interaction between the beamlets and the kerb design required to compensate for this interaction. All beamlets in the DNB must be focused to a single point in the duct, 20.665 m from the grounded grid, and the required geometrical aimings and aperture offsets have been calculated.

Singh, M. J. [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India); De Esch, H. P. L. [CEA-Cadarache, IRFM, F-13108 Saint-Paul-lez-Durance (France)

2010-01-15T23:59:59.000Z

271

PLT scaling laws for thermonuclear fusion power multiplication  

SciTech Connect

While present experiments are evaluated on the basis of confinement time, it is the fusion power multiplication factor, Q, and the fusion power which will be the parameters that measure the performance of ignition experiments and fusion reactors. We have determined the relationship of Q to tau/sub E/ and the Lawson number, n tau/sub e/, for ohmically heated plasmas from the Princeton Large Tokamak (PLT). Q, tau/sub E/, and n tau/sub E/ all increase with density at low densities. Above anti n/sub e/ approx. = 4 x 10/sup 13/ cm/sup -3/, tau/sub Ee/ approx. = 30 msec, or anti n/sub e/ tau/sub Ee/ approx. = 1.5 x 10/sup 12/ cm/sup -3/s, Q saturates. Q scaling has also been obtained on PLT as a function of toroidal magnetic field, plasma current, and auxiliary heating power.

Grisham, L.R.; Strachan, J.D.

1982-11-01T23:59:59.000Z

272

Experimental Capabilities  

NLE Websites -- All DOE Office Websites (Extended Search)

laser system. A major focus of NIF is a national effort to demonstrate ignition and thermonuclear burn in the laboratory. NIF also conducts a variety of experiments to study matter...

273

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)

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

Grossman, Lawrence

274

Reactor Safety Research Programs  

SciTech Connect

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.

Edler, S. K.

1981-07-01T23:59:59.000Z

275

Experimental Conclusions  

E-Print Network (OSTI)

temperature and high pressure pyrolysis of biomass performed at industrially relevant heating rates. (2-Pressure Biomass Pyrolysis in an Entrained-Flow Reactor 1Gautami Newalkar, 2Kristiina Iisa, 1Carsten Sievers and 1) Objective Results Experimental Conclusions 1000°C 600°C 4s 30s A major advantage of Biomass

Das, Suman

276

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

E-Print Network (OSTI)

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.

Christian Iliadis; Richard Longland; Art Champagne; Alain Coc

2010-04-23T23:59:59.000Z

277

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

E-Print Network (OSTI)

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 ...

Connaughton, V.

278

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

E-Print Network (OSTI)

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.

Potekhin, A Y

2012-01-01T23:59:59.000Z

279

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

SciTech Connect

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.

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

280

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

E-Print Network (OSTI)

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.

Tod E. Strohmayer

1999-11-19T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

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

E-Print Network (OSTI)

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...

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

2014-01-01T23:59:59.000Z

282

The 63Cu(?, p)66Zn cross section and the corresponding thermonuclear reaction rate  

Science Journals Connector (OSTI)

Differential cross sections and excitation functions for the reaction 63Cu(?, p)66Zn have been measured over the energy range E? = 6–10 MeV. Results of statistical model calculations are compared to the excitation functions for individual proton groups and are found to give good representations to within about a factor of two. The data and the calculated cross sections are used to determine the thermonuclear reaction rates for temperatures of astrophysical interest.

M.S. Islam; R.N. Boyd; P.B. Corn; D.P. Rath; X. Gu; G.W. Kolnicki

1989-01-01T23:59:59.000Z

283

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

E-Print Network (OSTI)

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.

S. Blinnikov; E. Sorokina

2002-12-30T23:59:59.000Z

284

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

E-Print Network (OSTI)

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.

Margarita Hernanz; Jordi Jose

2000-01-11T23:59:59.000Z

285

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

E-Print Network (OSTI)

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.

Theodore Liolios

2003-05-09T23:59:59.000Z

286

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

E-Print Network (OSTI)

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...

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

2015-01-01T23:59:59.000Z

287

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

E-Print Network (OSTI)

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...

Kushnir, Doron

2015-01-01T23:59:59.000Z

288

Irradiation Effect on the Interface of the Composites Used as the Insulation Materials in the Nuclear Fusion Reactor  

Science Journals Connector (OSTI)

Abstract In ITER (International Thermonuclear Experimental Reactor), the insulation materials containing polymeric matrix are the most radiation-sensitive among the materials constituting the superconducting magnet in the nuclear fusion reactor. Insulation materials are fabricated by impregnating the polymeric material into the stacks of alternating layers of polyimide films and glass cloth. There are a lot of studies about irradiation property of each constituent material, whereas few studies are reported about the irradiation effect on the resin -glass cloth and the resin –polyimide film boundary. In this study, we focused on the degradation of the resin-glass cloth boundary. The influence of the surface treatment and the weaving density of the glass cloth on the boundary degradation was evaluated by the mechanical properties before and after irradiation. The composite material specimens were prepared using the glass cloth with different surface treatment, and with different weaving density. The inter laminar shear strength (ILSS) test was conducted to examine the influence of the boundary on the radiation effect. In addition, the fracture mechanism were evaluated by optical micro-scope. Based on the results, it was indicated that the weaving density of the glass cloth is small influence on the irradiation effect and the radiation resistance was improved by the surface treatment.

M. Hayashi; Y. Nakata; F. Mishima; Y. Akiyama; S. Nishijima

2014-01-01T23:59:59.000Z

289

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

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

Data A Study and Comparison of SCR Reaction Kinetics from Reactor and Engine Experimental Data Presents experimental study of a Cu-zeolite SCR in both reactor and engine test cell,...

290

An experimental study of external reactor vessel cooling strategy on the critical heat flux using the graphene oxide nano-fluid  

SciTech Connect

External reactor vessel cooling (ERVC) for in-vessel retention (IVR) of corium as a key severe accident management strategy can be achieved by flooding the reactor cavity during a severe accident. In this accident mitigation strategy, the decay heat removal capability depends on whether the imposed heat flux exceeds critical heat flux (CHF). To provide sufficient cooling for high-power reactors such as APR1400, there have been some R and D efforts to use the reactor vessel with micro-porous coating and nano-fluids boiling-induced coating. The dispersion stability of graphene-oxide nano-fluid in the chemical conditions of flooding water that includes boric acid, lithium hydroxide (LiOH) and tri-sodium phosphate (TSP) was checked in terms of surface charge or zeta potential before the CHF experiments. Results showed that graphene-oxide nano-fluids were very stable under ERVC environment. The critical heat flux (CHF) on the reactor vessel external wall was measured using the small scale two-dimensional slide test section. The radius of the curvature is 0.1 m. The dimension of each part in the facility simulated the APR-1400. The heater was designed to produce the different heat flux. The magnitude of heat flux follows the one of the APR-1400 when the severe accident occurred. All tests were conducted under inlet subcooling 10 K. Graphene-oxide nano-fluids (concentration: 10 -4 V%) enhanced CHF limits up to about 20% at mass flux 50 kg/m{sup 2}s and 100 kg/m{sup 2}s in comparison with the results of the distilled water at same test condition. (authors)

Park, S. D.; Lee, S. W.; Kang, S.; Kim, S. M.; Seo, H.; Bang, I. C. [Ulsan National Inst. of Science and Technology UNIST, 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulasn Metropolitan City 689-798 (Korea, Republic of)

2012-07-01T23:59:59.000Z

291

Vertical compact torus injection into the STOR-M Tokamak.  

E-Print Network (OSTI)

??Central fuelling is a fundamental issue in the neat generation tokamak – ITER (International Thermonuclear Experimental Reactor). It is essential for optimization of the bootstrap… (more)

Liu, Dazhi

2006-01-01T23:59:59.000Z

292

Etude du comportement du tungstène sous irradiation : applications aux réacteurs de fusion.  

E-Print Network (OSTI)

??La fusion thermonucléaire est envisagée comme nouvelle source énergétique pratiquement inépuisable. Le projet ITER " International Thermonuclear Experimental Reactor " doit démontrer la faisabilité scientifique… (more)

Sidibe, Moussa

2014-01-01T23:59:59.000Z

293

US stays in global fusion deal — for a year  

Science Journals Connector (OSTI)

... intent last week that will allow the United States to continue work on the International Thermonuclear Experimental Reactor (ITER) design until next July. ...

Colin Macilwain

1998-10-01T23:59:59.000Z

294

Etude du comportement du tungstène sous irradiation : applications aux réacteurs de fusion.  

E-Print Network (OSTI)

??La fusion thermonucléaire est envisagée comme nouvelle source énergétique pratiquement inépuisable. Le projet ITER « International Thermonuclear Experimental Reactor » doit démontrer la faisabilité scientifique… (more)

Sidibe, Moussa

2014-01-01T23:59:59.000Z

295

E-Print Network 3.0 - aomori prefecture japan Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Help My Yahoo http:asia.news.yahoo.com041111kyodod869foe00.html Summary: Thermonuclear Experimental Reactor to Aomori Prefecture. "The Japanese business community should...

296

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

Energy Savers (EERE)

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

297

Timeline of Events: 1991 to 2000 | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

European Union, and Japan that will end U. S. participation in the International Thermonuclear Experimental Reactor (ITER) project by July 1999. October 19, 1998 The Department...

298

E-Print Network 3.0 - aichi prefecture japan Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

National efforts urged to win ITER location in Japan Japan Business Federation... Thermonuclear Experimental Reactor to Aomori Prefecture. "The Japanese business community should...

299

Oak Ridge Centers for Manufacturing Technology - Partnership...  

NLE Websites -- All DOE Office Websites (Extended Search)

lead for the heating, fueling and vacuum portions of the U.S.- ITER (International Thermonuclear Experimental Reactor). These testimonials cite the ORCMT as their launching pad...

300

Sandra Brereton  

NLE Websites -- All DOE Office Websites (Extended Search)

analysis, and she contributed to the early stages of design of the International Thermonuclear Experimental Reactor (ITER). She received a Bachelor's degree in chemical...

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

--No Title--  

NLE Websites -- All DOE Office Websites (Extended Search)

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

302

E-Print Network 3.0 - advanced fusion concepts Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

10.3 Alternate Concepts Fusion Technology FY 1995 -- 372.6 12;... International Thermonuclear Experimental Reactor Plasma Technologies Fusion Technologies Advanced Materials......

303

--No Title--  

NLE Websites -- All DOE Office Websites (Extended Search)

joined Martin Marietta Energy Systems as project coordinator for the International Thermonuclear Experimental Reactor (ITER) engineering design activities. He became the U.S. ITER...

304

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

NLE Websites -- All DOE Office Websites (Extended Search)

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

305

Our Mission  

NLE Websites -- All DOE Office Websites (Extended Search)

Collider (LHC), Coupled Model Intercomparison Project (CMIP), and International Thermonuclear Experimental Reactor (ITER), generate and exchange massive amounts of data. ESnet...

306

NUCLEAR MATERIALS RESEARCH PROGRESS REPORTS FROM 1977  

E-Print Network (OSTI)

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

Olander, D.R.

2012-01-01T23:59:59.000Z

307

RECENT PROGRESS IN HEAVY ION SOURCES  

E-Print Network (OSTI)

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

Clark, D.J.

2010-01-01T23:59:59.000Z

308

Experimental investigations on decay heat removal in advanced nuclear reactors using single heater rod test facility: Air alone in the annular gap  

SciTech Connect

During a loss of coolant accident in nuclear reactors, radiation heat transfer accounts for a significant amount of the total heat transfer in the fuel bundle. In case of heavy water moderator nuclear reactors, the decay heat of a fuel bundle enclosed in the pressure tube and outer concentric calandria tube can be transferred to the moderator. Radiation heat transfer plays a significant role in removal of decay heat from the fuel rods to the moderator, which is available outside the calandria tube. A single heater rod test facility is designed and fabricated as a part of preliminary investigations. The objective is to anticipate the capability of moderator to remove decay heat, from the reactor core, generated after shut down. The present paper focuses mainly on the role of moderator in removal of decay heat, for situation with air alone in the annular gap of pressure tube and calandria tube. It is seen that the naturally aspirated air is capable of removing the heat generated in the system compared to the standstill air or stagnant water situations. It is also seen that the flowing moderator is capable of removing a greater fraction of heat generated by the heater rod compared to a stagnant pool of boiling moderator. (author)

Bopche, Santosh B.; Sridharan, Arunkumar [Department of Mechanical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076 (India)

2010-11-15T23:59:59.000Z

309

On the Thermonuclear Runaway in Type Ia Supernovae: How to Run Away?  

Science Journals Connector (OSTI)

Type Ia supernovae (SNe Ia) are thought to be thermonuclear explosions of massive white dwarfs (WDs). We present the first study of multidimensional effects during the final hours prior to the thermonuclear runaway that leads to the explosion. The calculations utilize an implicit, two-dimensional hydrodynamic 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. In particular, 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 carbon-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 inward by convective flows. We find no evidence for multiple spot or strong off-center ignition. Convective velocities in the WD are on the order of 100 km s-1, which is well above the effective burning speeds in SNe Ia previously expected right after the runaway. In our calculations, the ignition occurs near the center. Then, for ? 0.5-1 s, 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 understanding of the detailed physics of the flame propagation, the deflagration to detonation transition, and the nucleosynthesis in the central layers. Our results strongly suggest the preconditioning of the progenitor as a key factor for our understanding of the diversity in SNe Ia.

P. Höflich; J. Stein

2002-01-01T23:59:59.000Z

310

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

E-Print Network (OSTI)

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.

M. Coleman Miller

1999-04-08T23:59:59.000Z

311

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

E-Print Network (OSTI)

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.

P. Hoeflich; J. Stein

2001-12-07T23:59:59.000Z

312

Interfacial effects in fast reactors  

E-Print Network (OSTI)

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 ...

Saidi, Mohammad Said

1979-01-01T23:59:59.000Z

313

Reactor physics project final report  

E-Print Network (OSTI)

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, ...

Driscoll, Michael J.

1970-01-01T23:59:59.000Z

314

Enhancement of Resonant Thermonuclear Reaction Rates in Extremely Dense Stellar Plasmas  

E-Print Network (OSTI)

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.

Naoki Itoh; Nami Tomizawa; Shinya Wanajo; Satoshi Nozawa

2002-12-06T23:59:59.000Z

315

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

E-Print Network (OSTI)

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).

Christian Iliadis; Richard Longland; Art Champagne; Alain Coc

2010-04-23T23:59:59.000Z

316

Concept of nuclear reactor pumped laser for ICF  

SciTech Connect

It is well known that attempts of civil utilization of fusion energy encounter many difficulties. At the same time we know that creation of thermonuclear weapon had been possible by using of the nuclear fission reaction as ignition of the nuclear fusion. The question arises{emdash}can help us similar idea in civil case and how that can be realized? In paper, it is shown that such idea is useful in this case and can be realized using nuclear reactor pumped laser. Contemporary state of research in nuclear reactor pumped laser for ICF field is considered. Progress by IPPE (Obninsk, Russia) in the development of the energy model of pulse reactor pumped laser system with waiting output energy about 50 kJ is reported. {copyright} {ital 1996 American Institute of Physics.}

Dyachenko, P.P. [Institute of Physics and Power Engineering, 1, Bondarenko Sq., Obninsk, 249020, Kaluga Reg. (Russia)

1996-05-01T23:59:59.000Z

317

Development of high-speed and wide-angle visible observation diagnostics on Experimental Advanced Superconducting Tokamak using catadioptric optics  

SciTech Connect

A new wide-angle endoscope for visible light observation on the Experimental Advanced Superconducting Tokamak (EAST) has been recently developed. The head section of the optical system is based on a mirror reflection design that is similar to the International Thermonuclear Experimental Reactor-like wide-angle observation diagnostic on the Joint European Torus. However, the optical system design has been simplified and improved. As a result, the global transmittance of the system is as high as 79.6% in the wavelength range from 380 to 780 nm, and the spatial resolution is <5 mm for the full depth of field (4000 mm). The optical system also has a large relative aperture (1:2.4) and can be applied in high-speed camera diagnostics. As an important diagnostic tool, the optical system has been installed on the HT-7 (Hefei Tokamak-7) for its final experimental campaign, and the experiments confirmed that it can be applied to the investigation of transient processes in plasma, such as ELMy eruptions in H-mode, on EAST.

Yang, J. H.; Hu, L. Q.; Zang, Q.; Han, X. F.; Shao, C. Q.; Sun, T. F.; Chen, H.; Wang, T. F.; Li, F. J.; Hu, A. L. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China)] [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China); Yang, X. F. [Jiangsu Province Key Laboratory of Modern Optical Technology, Soochow University, Suzhou, Jiangsu 215006 (China)] [Jiangsu Province Key Laboratory of Modern Optical Technology, Soochow University, Suzhou, Jiangsu 215006 (China)

2013-08-15T23:59:59.000Z

318

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

E-Print Network (OSTI)

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.

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

2015-02-13T23:59:59.000Z

319

thermonuclear functions  

E-Print Network (OSTI)

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.

M. Aslam Chaudhry

1999-01-01T23:59:59.000Z

320

Relativistic Collapse and Explosion of Rotating Supermassive Stars with Thermonuclear Effects  

Science Journals Connector (OSTI)

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 ?5 ? 105 M ? 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 a mass ?106 M ?. 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 ? ~ 1055 erg s–1. The total radiated energy in neutrinos varies between E ? ~ 1056 erg for models collapsing to a BH and E ? ~ 1045-1046 erg for models exploding.

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

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Thermonuclear .Ia Supernovae from Helium Shell Detonations: Explosion Models and Observables  

Science Journals Connector (OSTI)

During the early evolution of an AM Canum Venaticorum system, helium is accreted onto the surface of a white dwarf under conditions suitable for unstable thermonuclear ignition. The turbulent motions induced by the convective burning phase in the He envelope become strong enough to influence the propagation of burning fronts and may result in the onset of a detonation. Such an outcome would yield radioactive isotopes and a faint rapidly rising thermonuclear ".Ia" supernova. In this paper, we present hydrodynamic explosion models and observable outcomes of these He shell detonations for a range of initial core and envelope masses. The peak UVOIR bolometric luminosities range by a factor of 10 (from 5 ? 1041 to 5 ? 1042 erg s–1), and the R-band peak varies from M R,peak = –15 to –18. The rise times in all bands are very rapid (40Ca through 56Ni) and unburnt He. Thus, the spectra around peak light lack signs of intermediate-mass elements and are dominated by Ca II and Ti II features, with the caveat that our radiative transfer code does not include the nonthermal effects necessary to produce He features.

Ken J. Shen; Dan Kasen; Nevin N. Weinberg; Lars Bildsten; Evan Scannapieco

2010-01-01T23:59:59.000Z

322

Relativistic collapse and explosion of rotating supermassive stars with thermonuclear effects  

E-Print Network (OSTI)

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.

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

2012-02-01T23:59:59.000Z

323

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

E-Print Network (OSTI)

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.

Takuji Tsujimoto; Toshikazu Shigeyama

2006-01-16T23:59:59.000Z

324

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

E-Print Network (OSTI)

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.

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

2005-08-02T23:59:59.000Z

325

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

E-Print Network (OSTI)

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.

Lars Bildsten; Edward F. Brown

1996-09-23T23:59:59.000Z

326

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

E-Print Network (OSTI)

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.

D. J. B. Payne; A. Melatos

2006-07-11T23:59:59.000Z

327

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

E-Print Network (OSTI)

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.

Sudip Bhattacharyya; Tod E. Strohmayer

2007-08-27T23:59:59.000Z

328

Nuclear Reactor Severe Accident Experiments  

NLE Websites -- All DOE Office Websites (Extended Search)

Nuclear Reactor Severe Accident Experiments Nuclear Reactor Severe Accident Experiments Capabilities Engineering Experimentation Reactor Safety Testing and Analysis Overview Nuclear Reactor Severe Accident Experiments MAX NSTF SNAKE Aerosol Experiments System Components Laser Applications Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Nuclear Reactor Severe Accident Experiments 1 2 3 4 5 6 7 We perform experiments simulating reactor core melt phenomena in which molten core debris ("corium") erodes the concrete floor of a containment building. This occurred during the Fukushima nuclear power plant accident though the extent of concrete damage is yet unknown. This video shows the top view of a churning molten pool of uranium oxide at 2000°C (3600°F) seen during an experiment at Argonne. Corium behaves much like lava.

329

NUCLEAR REACTORS.  

E-Print Network (OSTI)

??Nuclear reactors are devices containing fissionable material in sufficient quantity and so arranged as to be capable of maintaining a controlled, self-sustaining NUCLEAR FISSION chain… (more)

Belachew, Dessalegn

2010-01-01T23:59:59.000Z

330

Analysis and synthesis techniques of nonlinear dynamical systems with applications to diagnostic of controlled thermonuclear fusion reactors.  

E-Print Network (OSTI)

??Nonlinear dynamical systems are of wide interest to engineers, physicists and mathematicians, and this is due to the fact that most of physical systems in… (more)

Pisano, Fabio

2013-01-01T23:59:59.000Z

331

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

E-Print Network (OSTI)

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.

Stanislav Fisenko; Igor Fisenko

2010-06-27T23:59:59.000Z

332

Plasma Barodiffusion in Inertial-Confinement-Fusion Implosions: Application to Observed Yield Anomalies in Thermonuclear Fuel Mixtures  

E-Print Network (OSTI)

Anomalies in Thermonuclear Fuel Mixtures Peter Amendt, O. L. Landen, and H. F. Robey Lawrence Livermore National Laboratory, Livermore, California 94551, USA C. K. Li and R. D. Petrasso Plasma Science and Fusion performance in general, and upcoming igni- tion tuning campaigns on the National Ignition Facility (NIF) [4

333

Spreading of Thermonuclear Flames on the Neutron Star in SAX J1808.4-3658: An Observational Tool  

Science Journals Connector (OSTI)

We analyze 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 find that the amplitude and burning region area evolutions are consistent with thermonuclear flames spreading on the neutron star surface. Based on this discussion, we infer that for the 2002 October 15 thermonuclear burst, the ignition likely occurred in the midlatitudes, 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.

Sudip Bhattacharyya; Tod E. Strohmayer

2006-01-01T23:59:59.000Z

334

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

E-Print Network (OSTI)

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.

Sudip Bhattacharyya; Tod E. Strohmayer

2006-04-03T23:59:59.000Z

335

Overview of Indian activities on fusion reactor materials  

Science Journals Connector (OSTI)

Abstract This paper on overview of Indian activities on fusion reactor materials describes in brief the efforts India has made to develop materials for the first wall of a tokamak, its blanket and superconducting magnet coils. Through a systematic and scientific approach, India has developed and commercially produced reduced activation ferritic/martensitic (RAFM) steel that is comparable to Eurofer 97. Powder of low activation ferritic/martensitic oxide dispersion strengthened steel with characteristics desired for its application in the first wall of a tokamak has been produced on the laboratory scale. V–4Cr–4Ti alloy was also prepared in the laboratory, and kinetics of hydrogen absorption in this was investigated. Cu–1 wt%Cr–0.1 wt%Zr – an alloy meant for use as heat transfer elements for hypervapotrons and heat sink for the first wall – was developed and characterized in detail for its aging behavior. The role of addition of a small quantity of Zr in its improved fatigue performance was delineated, and its diffusion bonding with both W and stainless steel was achieved using Ni as an interlayer. The alloy was produced in large quantities and used for manufacturing both the heat transfer elements and components for the International Thermonuclear Experimental Reactor (ITER). India has proposed to install and test a lead–lithium cooled ceramic breeder test blanket module (LLCB-TBM) at ITER. To meet this objective, efforts have been made to produce and characterize Li2TiO3 pebbles, and also improve the thermal conductivity of packed beds of these pebbles. Liquid metal loops have been set up and corrosion behavior of RAFM steel in flowing Pb–Li eutectic has been studied in the presence as well as absence of magnetic fields. To prevent permeation of tritium and reduce the magneto-hydro-dynamic drag, processes have been developed for coating alumina on RAFM steel. Apart from these activities, different approaches being attempted to make the U-shaped first wall of the TBM box are briefly described. India has also initiated the development of fusion grade superconductors. Success achieved in the fabrication of Nb3Sn based multi-filamentary wires using the internal tin process and cable-in-conduit-conductors is also briefly presented.

Srikumar Banerjee

2014-01-01T23:59:59.000Z

336

Analysis of the Thermonuclear Instability including Low-Power ICRH Minority Heating in IGNITOR  

E-Print Network (OSTI)

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...

Cardinali, Alessandro

2014-01-01T23:59:59.000Z

337

Spiral Disk Instability Can Drive Thermonuclear Explosions in Binary White Dwarf Mergers  

E-Print Network (OSTI)

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.

Kashyap, Rahul; García-Berro, Enrique; Aznar-Siguán, Gabriela; Ji, Suoqing; Lorén-Aguilar, Pablo

2015-01-01T23:59:59.000Z

338

Astrophysics Simulations from the ASC/Alliances Center for Astrophysical Thermonuclear Flashes  

DOE Data Explorer (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.

339

Thermonuclear Burning Regimes and the Use of SNe Ia in Cosmology  

E-Print Network (OSTI)

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.

E. I. Sorokina; S. I. Blinnikov; O. S. Bartunov

1999-10-02T23:59:59.000Z

340

Oxygen emission in remnants of thermonuclear supernovae as a probe for their progenitor system  

E-Print Network (OSTI)

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...

Kosenko, D; Kromer, M; Blinnikov, S I; Pakmor, R; Kaastra, J S

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Registration of the First Thermonuclear X-ray Burst from AX J1754.2-2754  

E-Print Network (OSTI)

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).

I. V. Chelovekov; S. A. Grebenev

2007-10-30T23:59:59.000Z

342

Small-scale Interaction of Turbulence with Thermonuclear Flames in Type Ia Supernovae  

E-Print Network (OSTI)

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.

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

1999-05-07T23:59:59.000Z

343

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

SciTech Connect

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.

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

344

BNL | Our History: Reactors as Research Tools  

NLE Websites -- All DOE Office Websites (Extended Search)

> See also: Accelerators > See also: Accelerators Brookhaven History: Using Reactors as Research Tools BGRR Brookhaven Graphite Research Reactor The Brookhaven Graphite Research Reactor (BGRR) was the Laboratory's first big machine and the first peace-time reactor built in the United States following World War II. The reactor's primary mission was to produce neutrons for scientific experimentation and to refine reactor technology. At the time, the BGRR could accommodate more simultaneous experiments than any other reactor. Scientists and engineers from every corner of the U.S. came to use the reactor, which was not only a source of neutrons for experiments, but also an excellent training facility. Researchers used the BGRR's neutrons as tools for studying atomic nuclei and the structure of solids, and to investigate many physical, chemical and

345

naval reactors  

National Nuclear Security Administration (NNSA)

After operating for 34 years and training over 14,000 sailors, the Department of Energy S1C Prototype Reactor Site in Windsor, Connecticut, was returned to "green field"...

346

Research reactors - an overview  

SciTech Connect

A broad overview of different types of research and type reactors is provided in this paper. Reactor designs and operating conditions are briefly described for four reactors. The reactor types described include swimming pool reactors, the High Flux Isotope Reactor, the Mark I TRIGA reactor, and the Advanced Neutron Source reactor. Emphasis in the descriptions is placed on safety-related features of the reactors. 7 refs., 7 figs., 2 tabs.

West, C.D.

1997-03-01T23:59:59.000Z

347

Light Water Reactor Sustainability  

NLE Websites -- All DOE Office Websites (Extended Search)

4 Light Water Reactor Sustainability ACCOMPLISHMENTS REPORT 2014 Accomplishments Report | Light Water Reactor Sustainability 2 T he mission of the Light Water Reactor...

348

Failure of a neutrino-driven explosion after core-collapse may lead to a thermonuclear supernova  

E-Print Network (OSTI)

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 ...

Kushnir, Doron

2014-01-01T23:59:59.000Z

349

Total cross sections and thermonuclear reaction rates for C13(d,n) and C14(d,n)  

Science Journals Connector (OSTI)

The C13(d,n) and C14(d,n) cross sections have been measured for 0.2?Ec.m.?2.1 MeV and 0.2?Ec.m.?1.3 MeV, respectively, using a 4? neutron detector. The cross sections are used to calculate the thermonuclear reaction rates for temperatures below 10 GK. The implications of these and other new nuclear-physics results for inhomogeneous primordial nucleosynthesis are discussed.

C. R. Brune and R. W. Kavanagh

1992-03-01T23:59:59.000Z

350

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)

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.

Yi Xu; Kohji Takahashi; Stephane Goriely; Marcel Arnould; Masahisa Ohta; Hiroaki Utsunomiya

2013-10-26T23:59:59.000Z

351

On the Cooling Tails of Thermonuclear X-ray Bursts: The IGR J17480–2446 Link  

Science Journals Connector (OSTI)

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.

M. Linares; D. Chakrabarty; M. van der Klis

2011-01-01T23:59:59.000Z

352

Pyroprocessing of oxidized sodium-bonded fast reactor fuel - An experimental study of treatment options for degraded EBR-II fuel  

SciTech Connect

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.

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

353

Catalytic reactor  

DOE Patents (OSTI)

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.

Aaron, Timothy Mark (East Amherst, NY); Shah, Minish Mahendra (East Amherst, NY); Jibb, Richard John (Amherst, NY)

2009-03-10T23:59:59.000Z

354

Thermonuclear (Type I) X-Ray Bursts Observed by the Rossi X-Ray Timing Explorer  

Science Journals Connector (OSTI)

We have assembled a sample of 1187 thermonuclear (type I) X-ray bursts from observations of 48 accreting neutron stars by the Rossi X-ray Timing Explorer, spanning more than 10 years. The sample contains examples of two of the three theoretical ignition regimes (confirmed via comparisons with numerical models) and likely examples of the third. We present a detailed analysis of the variation of the burst profiles, energetics, recurrence times, presence of photospheric radius expansion, and presence of burst oscillations, as a function of accretion rate. We estimated the distance for 35 sources exhibiting radius-expansion bursts, and found that the peak flux of such bursts varies typically by 13%. We classified sources into two main groups based on the burst properties: (1) both long and short bursts (indicating mixed H/He accretion), and (2) consistently short bursts (primarily He accretion), and we calculated the mean burst rate as a function of accretion rate for the two groups. The decrease in burst rate observed at > 0.06Edd$0.06˙{M}Edd$ --> ( -->2 ? 1037 ergs s?1) is associated with a transition in the persistent spectral state and (as has been suggested previously) may be related to the increasing role of steady He burning. We found many examples of bursts with recurrence times

Duncan K. Galloway; Michael P. Muno; Jacob M. Hartman; Dimitrios Psaltis; Deepto Chakrabarty

2008-01-01T23:59:59.000Z

355

Evidence for enhanced persistent emission during sub-Eddington thermonuclear bursts  

E-Print Network (OSTI)

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...

Worpel, Hauke; Price, Daniel J

2015-01-01T23:59:59.000Z

356

Thermonuclear reaction rate of 18O(p,gamma)19F  

E-Print Network (OSTI)

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.

M. Q. Buckner; C. Iliadis; J. M. Cesaratto; C. Howard; T. B. Clegg; A. E. Champagne; S. Daigle

2012-12-05T23:59:59.000Z

357

Screened thermonuclear reactions and predictive stellar evolution of detached double-lined eclipsing binaries  

E-Print Network (OSTI)

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.

Theodore Liolios; Theocharis Kosmas

2005-07-06T23:59:59.000Z

358

Evidence of thermonuclear flame spreading on neutron stars from burst rise oscillations  

E-Print Network (OSTI)

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...

Chakraborty, Manoneeta

2014-01-01T23:59:59.000Z

359

Rotational effects in thermonuclear Type I Bursts: equatorial crossing and directionality of flame spreading  

E-Print Network (OSTI)

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...

Cavecchi, Yuri; Levin, Yuri; Braithwaite, Jonathan

2014-01-01T23:59:59.000Z

360

On the applicability of the level set method beyond the flamelet regime in thermonuclear supernova simulations  

E-Print Network (OSTI)

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.

W. Schmidt

2007-01-15T23:59:59.000Z

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361

Advanced Safeguards Approaches for New Fast Reactors  

SciTech Connect

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.

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

362

Experimental results and numerical modeling of a high-performance large-scale cryopump. I. Test particle Monte Carlo simulation  

Science Journals Connector (OSTI)

For the torus of the nuclear fusion project ITER (originally the International Thermonuclear Experimental Reactor but also Latin: the way) eight high-performance large-scale customized cryopumps must be designed and manufactured to accommodate the very high pumping speeds and throughputs of the fusion exhaust gas needed to maintain the plasma under stable vacuum conditions and comply with other criteria which cannot be met by standard commercial vacuum pumps. Under an earlier research and development program a model pump of reduced scale based on active cryosorption on charcoal-coated panels at 4.5 K was manufactured and tested systematically. The present article focuses on the simulation of the true three-dimensional complex geometry of the model pump by the newly developed PROVAC3D Monte Carlo code. It is shown for gas throughputs of up to 1000 sccm (?1.69 Pa m3/s at T?=?0° C) in the free molecular regime that the numerical simulation results are in good agreement with the pumping speeds measured. Meanwhile the capture coefficient associated with the virtual region around the cryogenic panels and shields which holds for higher throughputs is calculated using this generic approach. This means that the test particle Monte Carlo simulations in free molecular flow can be used not only for the optimization of the pumping system but also for the supply of the input parameters necessary for the future direct simulation Monte Carlo in the full flow regime.

Xueli Luo; Christian Day; Horst Haas; Stylianos Varoutis

2011-01-01T23:59:59.000Z

363

Experimental results and numerical modeling of a high-performance large-scale cryopump. I. Test particle Monte Carlo simulation  

SciTech Connect

For the torus of the nuclear fusion project ITER (originally the International Thermonuclear Experimental Reactor, but also Latin: the way), eight high-performance large-scale customized cryopumps must be designed and manufactured to accommodate the very high pumping speeds and throughputs of the fusion exhaust gas needed to maintain the plasma under stable vacuum conditions and comply with other criteria which cannot be met by standard commercial vacuum pumps. Under an earlier research and development program, a model pump of reduced scale based on active cryosorption on charcoal-coated panels at 4.5 K was manufactured and tested systematically. The present article focuses on the simulation of the true three-dimensional complex geometry of the model pump by the newly developed ProVac3D Monte Carlo code. It is shown for gas throughputs of up to 1000 sccm ({approx}1.69 Pa m{sup 3}/s at T = 0 deg. C) in the free molecular regime that the numerical simulation results are in good agreement with the pumping speeds measured. Meanwhile, the capture coefficient associated with the virtual region around the cryogenic panels and shields which holds for higher throughputs is calculated using this generic approach. This means that the test particle Monte Carlo simulations in free molecular flow can be used not only for the optimization of the pumping system but also for the supply of the input parameters necessary for the future direct simulation Monte Carlo in the full flow regime.

Luo Xueli; Day, Christian; Haas, Horst; Varoutis, Stylianos [Karlsruhe Institute of Technology, Institute for Technical Physics, 76021 Karlsruhe (Germany)

2011-07-15T23:59:59.000Z

364

Reactor physics project progress report no. 2  

E-Print Network (OSTI)

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 ...

Driscoll, Michael J.

1969-01-01T23:59:59.000Z

365

Sensitivity study of explosive nucleosynthesis in type Ia supernovae: Modification of individual thermonuclear reaction rates  

Science Journals Connector (OSTI)

Background: Type Ia supernovae contribute significantly to the nucleosynthesis of many Fe-group and intermediate-mass elements. However, the robustness of nucleosynthesis obtained via models of this class of explosions has not been studied in depth until now.Purpose: We explore the sensitivity of the nucleosynthesis resulting from thermonuclear explosions of massive white dwarfs with respect to uncertainties in nuclear reaction rates. We put particular emphasis on indentifying the individual reactions rates that most strongly affect the isotopic products of these supernovae.Method: We have adopted a standard one-dimensional delayed detonation model of the explosion of a Chandrasekhar-mass white dwarf and have postprocessed the thermodynamic trajectories of every mass shell with a nucleosynthetic code to obtain the chemical composition of the ejected matter. We have considered increases (decreases) by a factor of 10 on the rates of 1196 nuclear reactions (simultaneously with their inverse reactions), repeating the nucleosynthesis calculations after modification of each reaction rate pair. We have computed as well hydrodynamic models for different rates of the fusion reactions of 12C and of 16O. From the calculations we have selected the reactions that have the largest impact on the supernova yields, and we have computed again the nucleosynthesis using two or three alternative prescriptions for their rates, taken from the JINA REACLIB database. For the three reactions with the largest sensitivity we have analyzed as well the temperature ranges where a modification of their rates has the strongest effect on nucleosynthesis.Results: The nucleosynthesis resulting from the type Ia supernova models is quite robust with respect to variations of nuclear reaction rates, with the exception of the reaction of fusion of two 12C nuclei. The energy of the explosion changes by less than ?4% when the rates of the reactions 12C+12C or 16O+16O are multiplied by a factor of ×10 or ×0.1. The changes in the nucleosynthesis owing to the modification of the rates of these fusion reactions are also quite modest; for instance, no species with a mass fraction larger than 0.02 experiences a variation of its yield larger than a factor of 2. We provide the sensitivity of the yields of the most abundant species with respect to the rates of the most intense reactions with protons, neutrons, and ?. In general, the yields of Fe-group nuclei are more robust than the yields of intermediate-mass elements. Among the species with yields larger than 10?8M?, 35S has the largest sensitivity to the nuclear reaction rates. It is remarkable that the reactions involving elements with Z>22 have a tiny influence on the supernova nucleosynthesis. Among the charged-particle reactions, the most influential on supernova nucleosynthesis are 30Si+p?31P+?, 20Ne+??24Mg+?, and 24Mg+??27Al+p. The temperatures at which a modification of their rate has a larger impact are in the range 2?T?4 GK.Conclusions: The explosion model (i.e., the assumed conditions and propagation of the flame) chiefly determines the element production of type Ia supernovae and derived quantities such as their luminosity, while the nuclear reaction rates used in the simulations have a small influence on the kinetic energy and final chemical composition of the ejecta. Our results show that the uncertainty in individual thermonuclear reaction rates cannot account for discrepancies of a factor of 2 between isotopic ratios in type Ia supernovae and those in the solar system, especially within the Fe group.

Eduardo Bravo and Gabriel Martínez-Pinedo

2012-05-18T23:59:59.000Z

366

Charged-Particle Thermonuclear Reaction Rates: I. Monte Carlo Method and Statistical Distributions  

E-Print Network (OSTI)

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.

Richard Longland; Christian Iliadis; Art Champagne; Joe Newton; Claudio Ugalde; Alain Coc; Ryan Fitzgerald

2010-04-23T23:59:59.000Z

367

Light Water Reactors Technology Development - Nuclear Reactors  

NLE Websites -- All DOE Office Websites (Extended Search)

Light Water Reactors Light Water Reactors About Director's Welcome Organization Achievements Highlights Fact Sheets, Brochures & Other Documents Multimedia Library Visit Argonne Work with Argonne Contact us Nuclear Energy Why Nuclear Energy? Why are some people afraid of Nuclear Energy? How do nuclear reactors work? Cheaper & Safer Nuclear Energy Helping to Solve the Nuclear Waste Problem Nuclear Reactors Nuclear Reactors Early Exploration Training Reactors Basic and Applied Science Research LWR Technology Development BORAX-III lighting Arco, Idaho (Press Release) Heavy Water and Graphite Reactors Fast Reactor Technology Integral Fast Reactor Argonne Reactor Tree CP-1 70th Anniversary CP-1 70th Anniversary Argonne's Nuclear Science and Technology Legacy Argonne's Nuclear Science and Technology Legacy

368

X-10 Graphite Reactor | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

X-10 Graphite Reactor X-10 Graphite Reactor X-10 Graphite Reactor X-10 Graphite Reactor When President Roosevelt in December 1942 authorized the Manhattan Project, the Oak Ridge site in eastern Tennessee had already been obtained and plans laid for an air-cooled experimental pile, a pilot chemical separation plant, and support facilities. The X-10 Graphite Reactor, designed and built in ten months, went into operation on November 4, 1943. The X-10 used neutrons emitted in the fission of uranium-235 to convert uranium-238 into a new element, plutonium-239. The reactor consists of a huge block of graphite, measuring 24 feet on each side, surrounded by several feet of high-density concrete as a radiation shield. The block is pierced by 1,248 horizontal diamond-shaped channels in

369

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

SciTech Connect

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.

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

370

Laser-Beam-Scattering Measurement of Ion Temperature in a ?-Pinch Plasma and Evidence for Thermonuclear Reactions  

Science Journals Connector (OSTI)

Results are reported on an experiment to measure the ion temperature in a 100-kJ ?-pinch deuterium plasma. A ruby laser was used for scattering observations at 5° and 90° using multichannel spectrum analyzers and gave n=1.05×1017 cm-3 and Ti=300 eV. An independent measurement of the density was made by means of Rayleigh scattering. The neutron yield from the plasma was measured to be 8×108 sec-1. The observed neutron emission was compared with that expected from a plasma with an ion temperature of 300 eV and was found to be of thermonuclear origin.

P. K. John

1972-08-01T23:59:59.000Z

371

Evidence for a new path to the self-sustainment of thermonuclear fusion in magnetically confined plasmas  

Science Journals Connector (OSTI)

In this work we provide the first explanation for observations made in 1997 on the Joint European Torus of unexpected ion heating with fusion-born alpha particles occurring over time scales much shorter than those theoretically foreseen. We demonstrate that non-thermal alpha particles above a critical concentration stabilize ion-drift-wave turbulence, therefore significantly reducing one of the main energy loss channels for thermal ions. As such ion heating occurs over times scales much shorter than those classically predicted, this mechanism opens new prospects on additional paths for the self-sustainment of thermonuclear fusion reactions in magnetically confined plasmas.

D. Testa; M. Albergante

2012-01-01T23:59:59.000Z

372

Photocatalytic reactor  

DOE Patents (OSTI)

A photocatalytic reactor is described for processing selected reactants from a fluid medium comprising at least one permeable photocatalytic membrane having a photocatalytic material. The material forms an area of chemically active sites when illuminated by light at selected wavelengths. When the fluid medium is passed through the illuminated membrane, the reactants are processed at these sites separating the processed fluid from the unprocessed fluid. A light source is provided and a light transmitting means, including an optical fiber, for transmitting light from the light source to the membrane. 4 figs.

Bischoff, B.L.; Fain, D.E.; Stockdale, J.A.D.

1999-01-19T23:59:59.000Z

373

The Effects of Variations in Nuclear Interactions on Nucleosynthesis in Thermonuclear Supernovae  

E-Print Network (OSTI)

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.

Anuj Parikh; Jordi Jose; Ivo R. Seitenzahl; Friedrich K. Roepke

2013-06-25T23:59:59.000Z

374

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)

for a Power Producing Thermonuclear Reactor, in Proceedingsorder for significant thermonuclear energy production, thethe approach to controlled thermonuclear fusion which uses

Prost, Lionel Robert

2007-01-01T23:59:59.000Z

375

Hybrid adsorptive membrane reactor  

DOE Patents (OSTI)

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.

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

376

On the Frequency Evolution of X-ray Brightness Oscillations During Thermonuclear X-ray Bursts: Evidence for Coherent Oscillations  

E-Print Network (OSTI)

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.

Tod E. Strohmayer; Craig B. Markwardt

1999-03-03T23:59:59.000Z

377

GEN-IV Reactors  

Science Journals Connector (OSTI)

Generation-IV reactors are a set of nuclear reactors currently being developed under international collaborations targeting ... economics, proliferation resistance, and physical protection of nuclear energy. Nuclear

Taek K. Kim

2013-01-01T23:59:59.000Z

378

The Netherlands Reactor Centre  

Science Journals Connector (OSTI)

... Two illustrated brochures in English have recently J. been issued by the Netherlands Reactor Centre ( ... Centre (Reactor Centrum Nederland). The first* gives a general survey of the ...

S. WEINTROUB

1964-04-04T23:59:59.000Z

379

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  

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.

Winterberg, F.

2009-10-29T23:59:59.000Z

380

Accelerators for Subcritical Molten-Salt Reactors  

SciTech Connect

Accelerator parameters for subcritical reactors have usually been based on using solid nuclear fuel much like that used in all operating critical reactors as well as the thorium burning accelerator-driven energy amplifier proposed by Rubbia et al. An attractive alternative reactor design that used molten salt fuel was experimentally studied at ORNL in the 1960s, where a critical molten salt reactor was successfully operated using enriched U235 or U233 tetrafluoride fuels. These experiments give confidence that an accelerator-driven subcritical molten salt reactor will work better than conventional reactors, having better efficiency due to their higher operating temperature, having the inherent safety of subcritical operation, and having constant purging of volatile radioactive elements to eliminate their accumulation and potential accidental release in dangerous amounts. Moreover, the requirements to drive a molten salt reactor can be considerably relaxed compared to a solid fuel reactor, especially regarding accelerator reliability and spallation neutron targetry, to the point that much of the required technology exists today. It is proposed that Project-X be developed into a prototype commercial machine to produce energy for the world by, for example, burning thorium in India and nuclear waste from conventional reactors in the USA.

Johnson, Roland (Muons, Inc.) [Muons, Inc.

2011-08-03T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Photoneutron effects on pulse reactor kinetics for the Annular Core Research Reactor (ACRR).  

SciTech Connect

The Annular Core Research Reactor (ACRR) is a swimming-pool type pulsed reactor that maintains an epithermal neutron flux and a nine-inch diameter central dry cavity. One of its uses is neutron and gamma-ray irradiation damage studies on electronic components under transient reactor power conditions. In analyzing the experimental results, careful attention must be paid to the kinetics associated with the reactor to ensure that the transient behavior of the electronic device is understood. Since the ACRR fuel maintains a substantial amount of beryllium, copious quantities of photoneutrons are produced that can significantly alter the expected behavior of the reactor power, especially following a reactor pulse. In order to understand these photoneutron effects on the reactor kinetics, the KIFLE transient reactor-analysis code was modified to include the photoneutron groups associated with the beryllium. The time-dependent behavior of the reactor power was analyzed for small and large pulses, assuming several initial conditions including following several pulses during the day, and following a long steady-state power run. The results indicate that, for these types of initial conditions, the photoneutron contribution to the reactor pulse energy can have a few to tens of percent effect.

Parma, Edward J., Jr.

2009-06-01T23:59:59.000Z

382

SRS Small Modular Reactors  

SciTech Connect

The small modular reactor program at the Savannah River Site and the Savannah River National Laboratory.

None

2012-04-27T23:59:59.000Z

383

SRS Small Modular Reactors  

ScienceCinema (OSTI)

The small modular reactor program at the Savannah River Site and the Savannah River National Laboratory.

None

2014-05-21T23:59:59.000Z

384

Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression  

DOE Patents (OSTI)

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.

Lasche, G.P.

1983-09-29T23:59:59.000Z

385

Multi-species Fokker-Planck calculations for D-T and D-3He mirror reactors  

Science Journals Connector (OSTI)

Values of the confinement parameter ntau and the figure of merit Q (the ratio of thermonuclear power to injected power) are obtained for postulated reactor conditions. The heart of the work is the numerical solution, under tested assumptions, of the coupled Fokker-Planck equations for as many as six charged species. A study is made of D-T and D-3He fuel cycles, including reaction products, in the following parameter ranges: mirror ratio, 2m03He fraction for the D-3He cycle, 0.05HeDTDHe

A H Futch Jr; J P Holdren; J Killeen; A A Mirin

1972-01-01T23:59:59.000Z

386

Nuclear reactor  

DOE Patents (OSTI)

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.

Thomson, Wallace B. (Severna Park, MD)

2004-03-16T23:59:59.000Z

387

On the Effect of Explosive Thermonuclear Burning on the Accreted Envelopes of White Dwarfs in Cataclysmic Variables  

Science Journals Connector (OSTI)

The detection of heavy elements at suprasolar abundances in the atmospheres of some accreting white dwarfs in cataclysmic variables (CVs), 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 CVs contain donor secondaries that have been contaminated by white dwarf remnant burning during the common envelope phase 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 systems with thermal timescale mass transfer. Implications for the progenitors of CVs are discussed and a new scenario for the white dwarf's accretion-nova-outburst is given.

Edward M. Sion; Warren Sparks

2014-01-01T23:59:59.000Z

388

On the Effect of Explosive Thermonuclear Burning on the Accreted Envelopes of White Dwarfs in Cataclysmic Variables  

E-Print Network (OSTI)

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.

Sion, Edward M

2014-01-01T23:59:59.000Z

389

Modeling for Anaerobic Fixed-Bed Biofilm Reactors  

SciTech Connect

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.

Liu, B. Y. M.; Pfeffer, J. T.

1989-06-01T23:59:59.000Z

390

Ion beam fusion  

Science Journals Connector (OSTI)

...that converts the fusion and blanket energy into...target gain G is the thermonuclear energy produced by the...Most concep- tual fusion power plants have a...and the International Thermonuclear Experimental Reactor...situation, the inertial fusion com- munity in the...

1999-01-01T23:59:59.000Z

391

Course: FUSION SCIENCE AND ENGINEERING Universit degli Studi di Padova  

E-Print Network (OSTI)

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

Cesare, Bernardo

392

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)

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 ...

Chiesa, Luisa

2006-01-01T23:59:59.000Z

393

E-Print Network 3.0 - advanced superconducting tokamak Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

Fusion 3 03012006 09:51 AMLoading "People's Daily Online --Chinese experimental thermonuclear reactor on discharge test in July" Page 1 of 1http:english.people.com.cn200603...

394

E-Print Network 3.0 - advanced tokamaks final Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Fusion 10 03012006 09:51 AMLoading "People's Daily Online --Chinese experimental thermonuclear reactor on discharge test in July" Page 1 of 1http:english.people.com.cn200603...

395

E-Print Network 3.0 - advanced tokamak discharges Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Fusion 3 03012006 09:51 AMLoading "People's Daily Online --Chinese experimental thermonuclear reactor on discharge test in July" Page 1 of 1http:english.people.com.cn200603...

396

Panel Report to FESAC: Review of the 1996 ITER Detailed Design Report  

Science Journals Connector (OSTI)

This report presents the results of a U.S. review of the 1996 Detailed Design Report (DDR) of the International Thermonuclear Experimental Reactor (ITER) project. It was prepared by a panel established by the ...

R. W. Conn; D. E. Baldwin; R. J. Briggs; J. D. Callen…

1999-12-01T23:59:59.000Z

397

Attrition reactor system  

DOE Patents (OSTI)

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.

Scott, C.D.; Davison, B.H.

1993-09-28T23:59:59.000Z

398

Elementary Reactor Physics  

Science Journals Connector (OSTI)

... THERE are few subjects which have developed at the rate at which reactor physics and ... physics and reactor theory have done. This, of course, is largely due to the circumstances in ...

J. F. HILL

1962-02-10T23:59:59.000Z

399

Colliding Beam Fusion Reactors  

Science Journals Connector (OSTI)

The recirculating power for virtually all types of fusion reactors has previously been calculated [1] with the Fokker–Planck equation. The reactors involve non-Maxwellian plasmas. The calculations are ... the rec...

Norman Rostoker; Artan Qerushi; Michl Binderbauer

2003-06-01T23:59:59.000Z

400

The thermonuclear rate for the 19F(a,p)22Ne reaction at stellar temperatures  

E-Print Network (OSTI)

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.

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

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

POTENTIAL BENCHMARKS FOR ACTINIDE PRODUCTION IN HANFORD REACTORS  

SciTech Connect

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.

PUIGH RJ; TOFFER H

2011-10-19T23:59:59.000Z

402

Prospects for spheromak fusion reactors  

Science Journals Connector (OSTI)

The reactor study of Hagenson and Krakowski demonstrated the attractiveness of the spheromak as a compact fusion reactor, based on...

T. K. Fowler; D. D. Hua

1995-06-01T23:59:59.000Z

403

SHARP: Reactor Performance and Safety Simulation Suite  

NLE Websites -- All DOE Office Websites (Extended Search)

SHARP SHARP Argonne National Laboratory's Reactor Performance and Safety Simulation Suite SHARP could save millions in nuclear reactor design and development... The Simulation-based High-efficiency Advanced Reactor Prototyping (SHARP) suite of codes enables virtual design and engineering of nuclear plant behavior that would be impractical from a traditional experimental approach. ...by leveraging the computational power of one of the world's most powerful supercomputers. Exploiting the power of Argonne Leadership Computing Facility's near-petascale computers, researchers have developed a set of simulation tools that provide a highly detailed description of the reactor core and the nuclear plant behavior. This enables the efficient and precise design of tomorrow's safe and clean nuclear energy sources.

404

Advanced Test Reactor Tour  

SciTech Connect

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.

Miley, Don

2011-01-01T23:59:59.000Z

405

Improved vortex reactor system  

DOE Patents (OSTI)

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.

Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO)

1995-01-01T23:59:59.000Z

406

Advanced Test Reactor Tour  

ScienceCinema (OSTI)

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.

Miley, Don

2013-05-28T23:59:59.000Z

407

Photo of the Week: The Sixth Zero Power Reactor | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

The Sixth Zero Power Reactor The Sixth Zero Power Reactor Photo of the Week: The Sixth Zero Power Reactor November 13, 2013 - 4:41pm Addthis In 1958, Argonne National Laboratory began the construction of several zero-power reactors (ZPRs), which are nuclear fission reactors that don't actually generate any power. Scientists developed ZPRs to assess the performance of various reactor core configurations before actually building a full nuclear reactor. A series of ZPRs were built leading up to the construction of the Experimental Breeder Reactor-II, a sodium-cooled fast reactor power plant. In this 1970 photo, an Argonne scientist is loading the matrices of the ZPR-VI reactor prior to its first operation using plutonium fuel. | Photo courtesy of the Department of Energy. In 1958, Argonne National Laboratory began the construction of several

408

Advanced Computational Thermal Fluid Physics (CTFP) and Its Assessment for Light Water Reactors and Supercritical Reactors  

SciTech Connect

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.

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

409

Hydrogen production in a reversible flow filtration combustion reactor  

Science Journals Connector (OSTI)

The noncatalytic process of syngas production by means of partial oxidation of ... by air oxygen in a reversible flow filtration combustion reactor has been investigated experimentally. We have ... providing the ...

Yu. M. Dmitrenko; P. A. Klevan

2011-11-01T23:59:59.000Z

410

Stress Management as an Enabling Technology for High-Field Superconducting Dipole Magnets  

E-Print Network (OSTI)

-Pounds HD High field Dipole HGQ High Gradient Quadrupole HQ High field Quadrupole HT Heat Treatment IC Critical Current IFCC Inter-Filament Coupling Currents ITER International Thermonuclear Experimental Reactor vi LARP LHC Accelerator... pressure impregnation (VPI) vessel using NbTi conductor [1, 2]. TAMU2 verified the heat treatment equipment and tested the stress management technology at low field using low Jc Nb3Sn conductor from the International Thermonuclear Experimental Reactor...

Holik, Eddie Frank

2014-06-03T23:59:59.000Z

411

The Argonaut Reactor - Reactors designed/built by Argonne National  

NLE Websites -- All DOE Office Websites (Extended Search)

Achievements > Achievements > Argonne Reactors > Training Reactors About Director's Welcome Organization Achievements Highlights Fact Sheets, Brochures & Other Documents Multimedia Library Visit Argonne Work with Argonne Contact us Nuclear Energy Why Nuclear Energy? Why are some people afraid of Nuclear Energy? How do nuclear reactors work? Cheaper & Safer Nuclear Energy Helping to Solve the Nuclear Waste Problem Nuclear Reactors Nuclear Reactors Early Exploration Training Reactors Basic and Applied Science Research LWR Technology Development BORAX-III lighting Arco, Idaho (Press Release) Heavy Water and Graphite Reactors Fast Reactor Technology Integral Fast Reactor Argonne Reactor Tree CP-1 70th Anniversary CP-1 70th Anniversary Argonne's Nuclear Science and Technology Legacy

412

The longest thermonuclear X-ray burst ever observed? (A BeppoSAX Wide Field Camera observation of 4U 1735-44)  

E-Print Network (OSTI)

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.

R. Cornelisse; J. Heise; E. Kuulkers; F. Verbunt; J. J. M. in 't Zand

2000-03-30T23:59:59.000Z

413

Generating Unstructured Nuclear Reactor Core Meshes in Parallel  

Science Journals Connector (OSTI)

Abstract Recent advances in supercomputers and parallel solver techniques have enabled users to run large simulations problems using millions of processors. Techniques for multiphysics nuclear reactor core simulations are under active development in several countries. Most of these techniques require large unstructured meshes that can be hard to generate in a standalone desktop computers because of high memory requirements, limited processing power, and other complexities. We have previously reported on a hierarchical lattice-based approach for generating reactor core meshes. Here, we describe efforts to exploit coarse-grained parallelism during reactor assembly and reactor core mesh generation processes. We highlight several reactor core examples including a very high temperature reactor, a full-core model of the Korean MONJU reactor, a ¼ pressurized water reactor core, the fast reactor Experimental Breeder Reactor-II core with a XX09 assembly, and an advanced breeder test reactor core. The times required to generate large mesh models, along with speedups obtained from running these problems in parallel, are reported. A graphical user interface to the tools described here has also been developed.

Rajeev Jain; Timothy J. Tautges

2014-01-01T23:59:59.000Z

414

Reactor vessel support system  

DOE Patents (OSTI)

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.

Golden, Martin P. (Trafford, PA); Holley, John C. (McKeesport, PA)

1982-01-01T23:59:59.000Z

415

OPTIMAL DESIGN OF A HIGH PRESSURE ORGANOMETALLIC CHEMICAL VAPOR DEPOSITION REACTOR  

E-Print Network (OSTI)

OPTIMAL DESIGN OF A HIGH PRESSURE ORGANOMETALLIC CHEMICAL VAPOR DEPOSITION REACTOR K.J. BACHMANN of computer simulations as an optimal design tool which lessens the costs in time and effort in experimental vapor deposition (HPOMCVD) reactor for use in thin film crystal growth. The advantages of such a reactor

416

CAD Technique for Microwave Chemistry Reactors with Energy Efficiency Optimized for Different Reactants  

E-Print Network (OSTI)

CAD Technique for Microwave Chemistry Reactors with Energy Efficiency Optimized for Different in experimental development of large- scale and highly-productive reactors. This paper proposes to address this issue by developing microwave chemistry reactors as microwave systems, rather than as black

Yakovlev, Vadim

417

Reactor water cleanup system  

DOE Patents (OSTI)

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.

Gluntz, Douglas M. (San Jose, CA); Taft, William E. (Los Gatos, CA)

1994-01-01T23:59:59.000Z

418

Reactor water cleanup system  

DOE Patents (OSTI)

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.

Gluntz, D.M.; Taft, W.E.

1994-12-20T23:59:59.000Z

419

Systematic variation in the apparent burning area of thermonuclear bursts and its implication for neutron star radius measurement  

E-Print Network (OSTI)

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.

Sudip Bhattacharyya; M. Coleman Miller; Duncan K. Galloway

2009-08-28T23:59:59.000Z

420

The Long Term Stability of Oscillations During Thermonuclear X-ray Bursts: Constraining the Binary X-ray Mass Function  

E-Print Network (OSTI)

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.

Tod E. Strohmayer; William Zhang; Jean H. Swank; Iosif Lapidus

1998-06-18T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Experimental Investigation of Chemical-Looping Combustion in Packed Beds: A Parametric Study  

Science Journals Connector (OSTI)

Recently a novel reactor concept for chemical-looping combustion (CLC) has been proposed exploiting dynamically operated packed beds. In this work, an experimental parametric study on this reactor concept has been carried out. The effects of operating ...

S. Noorman; F. Gallucci; M. van Sint Annaland; J. A. M. Kuipers

2011-01-18T23:59:59.000Z

422

Role of research reactors in training of NPP personnel with special focus on training reactor VR-1  

SciTech Connect

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)

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

423

Idaho Site Obtains Patent for Nuclear Reactor Sodium Cleanup Treatment |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Obtains Patent for Nuclear Reactor Sodium Cleanup Obtains Patent for Nuclear Reactor Sodium Cleanup Treatment Idaho Site Obtains Patent for Nuclear Reactor Sodium Cleanup Treatment March 28, 2013 - 12:00pm Addthis CWI engineers Jeff Jones, David Tolman, right, and Kirk Dooley (seated) developed a treatment to safely dissolve a bicarbonate crust and treat and remove the sodium in the Experimental Breeder Reactor-II at the Idaho site. CWI engineers Jeff Jones, David Tolman, right, and Kirk Dooley (seated) developed a treatment to safely dissolve a bicarbonate crust and treat and remove the sodium in the Experimental Breeder Reactor-II at the Idaho site. Piping in the east boiler basement of the sodium processing building was color coded for easy identification. Orange indicates sodium and green identifies cooling water.

424

Idaho Site Obtains Patent for Nuclear Reactor Sodium Cleanup Treatment |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Idaho Site Obtains Patent for Nuclear Reactor Sodium Cleanup Idaho Site Obtains Patent for Nuclear Reactor Sodium Cleanup Treatment Idaho Site Obtains Patent for Nuclear Reactor Sodium Cleanup Treatment March 28, 2013 - 12:00pm Addthis CWI engineers Jeff Jones, David Tolman, right, and Kirk Dooley (seated) developed a treatment to safely dissolve a bicarbonate crust and treat and remove the sodium in the Experimental Breeder Reactor-II at the Idaho site. CWI engineers Jeff Jones, David Tolman, right, and Kirk Dooley (seated) developed a treatment to safely dissolve a bicarbonate crust and treat and remove the sodium in the Experimental Breeder Reactor-II at the Idaho site. Piping in the east boiler basement of the sodium processing building was color coded for easy identification. Orange indicates sodium and green identifies cooling water.

425

Creation of a neutrino laboratory for search for sterile neutrino at SM-3 reactor  

E-Print Network (OSTI)

In connection with the question of possible existence of sterile neutrino the laboratory on the basis of SM-3 reactor was created to search for oscillations of reactor antineutrino. A prototype of a neutrino detector with scintillator volume of 400 l can be moved at the distance of 6-11 m from the reactor core. The measurements of background conditions have been made. It is shown that the main experimental problem is associated with cosmic radiation background. Test measurements of dependence of a reactor antineutrino flux on the distance from a reactor core have been made. The prospects of search for oscillations of reactor antineutrino at short distances are discussed.

Serebrov, A P; Samoylov, R M; Fomin, A K; Zinoviev, V G; Neustroev, P V; Golovtsov, V L; Gruzinsky, N V; Solovey, V A; Cherniy, A V; Zherebtsov, O M; Martemyanov, V P; Zinoev, V G; Tarasenkov, V G; Aleshin, V I; Petelin, A L; Pavlov, S V; Izhutov, A L; Sazontov, S A; Ryazanov, D K; Gromov, M O; Afanasiev, V V; Matrosov, L N; Matrosova, M Yu

2015-01-01T23:59:59.000Z

426

Computer simulation of multi-elemental fusion reactor materials.  

E-Print Network (OSTI)

??Thermonuclear fusion is a sustainable energy solution, in which energy is produced using similar processes as in the sun. In this technology hydrogen isotopes are… (more)

Vörtler, Katharina

2011-01-01T23:59:59.000Z

427

Antineutrino reactor safeguards - a case study  

E-Print Network (OSTI)

Antineutrinos have been proposed as a means of reactor safeguards for more than 30 years and there has been impressive experimental progress in neutrino detection. In this paper we conduct, for the first time, a case study of the application of antineutrino safeguards to a real-world scenario - the North Korean nuclear crisis in 1994. We derive detection limits to a partial or full core discharge in 1989 based on actual IAEA safeguards access and find that two independent methods would have yielded positive evidence for a second core with very high confidence. To generalize our results, we provide detailed estimates for the sensitivity to the plutonium content of various types of reactors, including most types of plutonium production reactors, based on detailed reactor simulations. A key finding of this study is that a wide class of reactors with a thermal power of less than 0.1-1 GWth can be safeguarded achieving IAEA goals for quantitative sensitivity and timeliness with detectors right outside the reactor ...

Christensen, Eric; Jaffke, Patrick

2013-01-01T23:59:59.000Z

428

The integral fast reactor fuel cycle  

SciTech Connect

The liquid-metal reactor (LMR) has the potential to extend the uranium resource by a factor of 50 to 100 over current commercial light water reactors (LWRs). In the integral fast reactor (IFR) development program, the entire reactor system - reactor, fuel cycle, and waste process - is being developed and optimized at the same time as a single integral entity. A key feature of the IFR concept is the metallic fuel. The lead irradiation tests on the new U-Pu-Zr metallic fuel in the Experimental Breeder Reactor II have surpassed 185000 MWd/t burnup, and its high burnup capability has now been fully demonstrated. The metallic fuel also allows a radically improved fuel cycle technology. Pyroprocessing, which utilizes high temperatures and molten salt and molten metal solvents, can be advantageously utilized for processing metal fuels because the product is metal suitable for fabrication into new fuel elements. Direct production of a metal product avoids expensive and cumbersome chemical conversion steps that would result from use of the conventional Purex solvent extraction process. The key step in the IFR process is electrorefining, which provides for recovery of the valuable fuel constituents, uranium and plutonium, and for removal of fission products. A notable feature of the IFR process is that the actinide elements accompany plutonium through the process. This results in a major advantage in the high-level waste management.

Chang, Y.I. (Argonne National Lab., IL (United States))

1990-01-01T23:59:59.000Z

429

Generation -IV Reactor Concepts  

NLE Websites -- All DOE Office Websites (Extended Search)

Generation-IV Reactor Concepts Generation-IV Reactor Concepts Thomas H. Fanning Argonne National Laboratory 9700 South Cass Avenue Argonne, Illinois 60439, USA The Generation-IV International Forum (GIF) is a multi-national research and development (R&D) collaboration. The GIF pursues the development of advanced, next generation reactor technology with goals to improve: a) sustainability (effective fuel utilization and minimization of waste) b) economics (competitiveness with respect to other energy sources) c) safety and reliability (e.g., no need for offsite emergency response), and d) proliferation resistance and physical protection The GIF Technology Roadmap exercise selected six generic systems for further study: the Gas- cooled Fast Reactor (GFR), the Lead-cooled Fast Reactor (LFR), the Molten Salt Reactor (MSR),

430

Power Reactor Progress  

Science Journals Connector (OSTI)

Argonne kicks off EBWR; Allis-Chalmers plans power reactor using both nuclear and conventional fuels ... NUCLEAR POWER took two giant steps last week. ... Just as the first nuclear power system in the U. S. designed and built solely for the generation of electric power went into full operation at Argonne, Allis-Chalmers came up with a new twist in power reactors—a controlled recirculation boiling reactor (CRBR) using both nuclear and conventional fuels (C&EN, Feb. 18, page 7). ...

1957-02-25T23:59:59.000Z

431

Improved vortex reactor system  

DOE Patents (OSTI)

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.

Diebold, J.P.; Scahill, J.W.

1995-05-09T23:59:59.000Z

432

PLASMA-PHYSICS-21 Heavy ion driven reactor-size double shell inertial fusion targets*  

E-Print Network (OSTI)

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

M. C. Serna Moreno; N. A. Tahir; J. J. López Cela; A. R. Piriz; D. H. H. Hoffmann

433

Tokamak reactor first wall  

DOE Patents (OSTI)

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.

Creedon, R.L.; Levine, H.E.; Wong, C.; Battaglia, J.

1984-11-20T23:59:59.000Z

434

Advanced Nuclear Research Reactor  

SciTech Connect

This report describes technical modifications implemented by INVAP to improve the safety of the Research Reactors the company designs and builds.

Lolich, J.V.

2004-10-06T23:59:59.000Z

435

Charged-Particle Thermonuclear Reaction Rates: II. Tables and Graphs of Reaction Rates and Probability Density Functions  

E-Print Network (OSTI)

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.

Christian Iliadis; Richard Longland; Art Champagne; Alain Coc; Ryan Fitzgerald

2010-04-23T23:59:59.000Z

436

Investigation of thermonuclear $^{18}$Ne($?$,$p$)$^{21}$Na rate via resonant elastic scattering of $^{21}$Na+$p$  

E-Print Network (OSTI)

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.

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

437

A TEN MEGAWATT BOILING HETEROGENEOUS PACKAGE POWER REACTOR. Reactor...  

Office of Scientific and Technical Information (OSTI)

A TEN MEGAWATT BOILING HETEROGENEOUS PACKAGE POWER REACTOR. Reactor Design and Feasibility Problem Re-direct Destination: Temp Data Fields Rosen, M. A.; Coburn, D. B.; Flynn, T....

438

Portfolio for fast reactor collaboration  

SciTech Connect

The development of the LMFBR type reactor in the United Kingdom is reviewed. Design characteristics of a commercial demonstration fast reactor are presented and compared with the Super Phenix reactor.

Rippon, S.

1981-12-01T23:59:59.000Z

439

Handbook of Reactor Physics  

Science Journals Connector (OSTI)

... THIS handbook is one volume in a series sponsored by the United States Atomic Energy Commission with ... data and reference information in the field of reactors. The volume is devoted to reactor physics and radiation shielding, the latter subject occupying approximately a quarter of the book.

PETER W. MUMMERY

1956-08-25T23:59:59.000Z

440

Fast reactor safety  

Science Journals Connector (OSTI)

... SIR, - In his article on fast reactor safety (26 July, page 270) Norman Dombey claims to introduce to non-specialists ... , page 270) Norman Dombey claims to introduce to non-specialists some features of fast reactors that are not available outside the technical literature. The non-specialist would do well ...

R.D. SMITH

1979-08-23T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Instrumentation of Nuclear Reactors  

Science Journals Connector (OSTI)

... s Lecture Theatre on January 8, a symposium of papers on the instrumentation of nuclear reactors was organized, at which about five hundred members and visitors attended, including guests from ... the Institution, took the chair and introduced Sir John Cockcroft, whose lecture on "Nuclear Reactors and their Applications" provided a general background for the three specialized papers which followed. ...

1953-03-07T23:59:59.000Z

442

Nuclear Research Reactors  

Science Journals Connector (OSTI)

... their countries for the advent of nuclear power. A few countries had built large research reactors for the production of isotopes and to study the behaviour of nuclear fuel, but ... production of isotopes and to study the behaviour of nuclear fuel, but the small training reactor had not been developed. Since then, research ...

T. E. ALLIBONE

1963-07-20T23:59:59.000Z

443

Computer simulations help design new nuclear reactors  

NLE Websites -- All DOE Office Websites (Extended Search)

Computer simulations help design new nuclear reactors Director's Welcome Organization Achievements Highlights Fact Sheets, Brochures & Other Documents Multimedia Library About Nuclear Energy Nuclear Reactors Designed by Argonne Argonne's Nuclear Science and Technology Legacy Opportunities within NE Division Visit Argonne Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Celebrating the 70th Anniversary of Chicago Pile 1 (CP-1) Argonne OutLoud on Nuclear Energy Argonne Energy Showcase 2012 Highlights Bookmark and Share Reprinted from "Argonne Now" - Spring 2008 Physicist Won-Sik Yang and computer scientist Andrew Siegel hold a fuel rod assembly in front of a model of the Experimental Breeder Reactor-II

444

Canadian university research reactors  

SciTech Connect

In Canada there are seven university research reactors: one medium-power (2-MW) swimming pool reactor at McMaster University and six low-power (20-kW) SLOWPOKE reactors at Dalhousie University, Ecole Polytechnique, the Royal Military College, the University of Toronto, the University of Saskatchewan, and the University of Alberta. This paper describes primarily the McMaster Nuclear Reactor (MNR), which operates on a wider scale than the SLOWPOKE reactors. The MNR has over a hundred user groups and is a very broad-based tool. The main applications are in the following areas: (1) neutron activation analysis (NAA); (2) isotope production; (3) neutron beam research; (4) nuclear engineering; (5) neutron radiography; and (6) nuclear physics.

Ernst, P.C.; Collins, M.F.

1989-11-01T23:59:59.000Z

445

Reactor & Nuclear Systems Publications | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Nuclear Science Home | Science & Discovery | Nuclear Science | Publications and Reports | Reactor and Nuclear Systems Publications SHARE Reactor and Nuclear Systems Publications...

446

Three-dimensional equilibria in axially symmetric tokamaks  

Science Journals Connector (OSTI)

...Thermonuclear Experimental Reactor. When bifurcated 3D...candidates for a fusion reactor. The research we describe...algorithm that is used. The reliability of the code has been...iota}. Computational Analysis 3D computer codes are...desirable properties for a reactor (10). The coils for...

Paul R. Garabedian

2006-01-01T23:59:59.000Z

447

Margaret Thatcher's influence on British science  

Science Journals Connector (OSTI)

...long-term: in 1990 a commercial fusion reactor was promised by the...built. The most productive fusion reaction for energy generation...and the economic case for a fusion reactor, as for a fast breeder...Russia (the International Thermonuclear Experimental Reactor). Agriculture...

2014-01-01T23:59:59.000Z

448

Nuclear reactor control column  

DOE Patents (OSTI)

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.

Bachovchin, Dennis M. (Plum Borough, PA)

1982-01-01T23:59:59.000Z

449

Determining Reactor Flux from Xenon-136 and Cesium-135 in Spent Fuel  

E-Print Network (OSTI)

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.

A. C. Hayes; Gerard Jungman

2012-05-30T23:59:59.000Z

450

Nuclear reactor reflector  

DOE Patents (OSTI)

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.

Hopkins, Ronald J. (Pensacola, FL); Land, John T. (Pensacola, FL); Misvel, Michael C. (Pensacola, FL)

1994-01-01T23:59:59.000Z

451

Spherical torus fusion reactor  

DOE Patents (OSTI)

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.

Martin Peng, Y.K.M.

1985-10-03T23:59:59.000Z

452

Theoretical and experimental study of space charge in intense ion beams  

Science Journals Connector (OSTI)

The highly collimated beams of energetic neutral atoms used in controlled thermonuclear fusion research (CTR) require the virtual elimination of space-charge forces in the primary ion beam in order to minimize the angular divergence. A model is presented which describes the behavior of an intense ion beam passing through a gas cell. This theory is used to derive the space-charge field produced by such a beam and shows how its effect can be minimized. This model agrees well with experimental measurements and enables emittance-dominated beams of very high brightness to be obtained which could find applications in fields other than CTR.

A. J. T. Holmes

1979-01-01T23:59:59.000Z

453

Experimental Psychology  

Science Journals Connector (OSTI)

... of the British Medical Bulletin, an 80-page issue has been published concentrating on experimental psychology*. This is introduced and edited by Prof. Summerfield and contains fifteen short, but ... the question of just whom the work is intended for. Medical people unacquainted with experimental psychology will find the going very hard; because of the limited space available to each ...

H. J. EYSENCK

1964-04-18T23:59:59.000Z

454

Experimental Psychology  

Science Journals Connector (OSTI)

... French publishers, Presses Universitaires de France, have produced a nine-volume work on experimental psychology, broadly conceived, under the joint editorship of Professors Fraisse and Piaget. Volume 1, ... Professors Fraisse and Piaget. Volume 1, concerned with the history and method of experimental psychology, first appeared in 1963 in French. It consists of the following four chapters: ...

W. SLUCKIN

1968-06-15T23:59:59.000Z

455

Experimental Psychology  

Science Journals Connector (OSTI)

... Expérimental is the first JL treatise of its kind since the Harvard Handbook of Experimental Psychology, edited by S. S. Stevens and published in 1951. In a way, ... come from France, for although there has been a distinguished French psychological tradition, experimental psychology has never held a central place in it. Nor has the output of the ...

O. L. ZANGWILL

1964-07-11T23:59:59.000Z

456

On Thermonuclear Reaction Rates  

E-Print Network (OSTI)

Nuclear reactions govern major aspects of the chemical evolution od galaxies and stars. Analytic study of the reaction rates and reaction probability integrals is attempted here. Exact expressions for the reaction rates and reaction probability integrals for nuclear reactions in the case of nonresonant, modified nonresonant, screened nonresonant and resonant cases are given. These are expressed in terms of H-functions, G-functions and in computable series forms. Computational aspects are also discussed.

H. J. Haubold; A. M. Mathai

1996-12-02T23:59:59.000Z

457

Kinetic model of the MTG process taking into account the catalyst deactivation. Reactor simulation  

Science Journals Connector (OSTI)

A kinetic model for the deactivation of catalyst (based on a HZSM5 zeolite) in the transformation of methanol into gasoline is proposed from results obtained in an isothermal fixed bed integral reactor. The kinetic model takes into account the effect of the composition of the lumps of oxygenates, light olefins and rest of products on the catalyst deactivation along the reactor. The model allows for simulating the integral reactor and for studying the influence of the operating conditions on selectivity towards different lumps in the MTG process. The resukts have been experimentally proven in an isothermal integral reactor and are in agreement with the results of coke deposition along the reactor.

A.G. Gayubo; P.L. Benito; A.T. Aguayo; M. Castilla; J. Bilbao

1996-01-01T23:59:59.000Z

458

An Improved Reaction Rate Formulation for Charged-Particle Induced Thermonuclear Reaction of {sup 2}H(d,{gamma}){sup 4}He  

SciTech Connect

The reaction rate formula utilized in compilations such as the Nuclear Astrophysics Compilation of Reaction Rates (NACRE) uses low energy approximation due to temperatures in stars are in the region of a few keVs. Most nuclear reaction experiments were done in MeV range and the interior temperatures of massive stars are {approx}10{sup 9} K. Hence an improved formulation for calculating the nuclear reaction rate that is applicable to high temperatures is discussed in this work. The exact tunneling probability that is applicable for all energies is obtained by solving the Schroedinger equation. This yields an enhanced expression for the astrophysical S-factor for calculating the thermonuclear reaction rate at high temperature. The thermonuclear reaction rate from this work is applied to the {sup 2}H(d,{gamma}){sup 4}He reaction and is compared with the NACRE compilation. This improved reaction rate can be included in the nuclear reaction network in a Big Bang nucleosynthesis (BBN) code or a stellar nuclear network code.

Aziz, Azni Abdul; Yusof, Norhasliza; Idris, Mahirah; Kassim, Hasan Abu [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-03-30T23:59:59.000Z

459

Reactor Thermal-Hydraulics  

NLE Websites -- All DOE Office Websites (Extended Search)

Thermal-Hydraulics Thermal-Hydraulics Dr. Tanju Sofu, Argonne National Laboratory In a power reactor, the energy produced in fission reaction manifests itself as heat to be removed by a coolant and utilized in a thermodynamic energy conversion cycle to produce electricity. A simplified schematic of a typical nuclear power plant is shown in the diagram below. Primary coolant loop Steam Reactor Heat exchanger Primary pump Secondary pump Condenser Turbine Water Although this process is essentially the same as in any other steam plant configuration, the power density in a nuclear reactor core is typically four orders of magnitude higher than a fossil fueled plant and therefore it poses significant heat transfer challenges. Maximum power that can be obtained from a nuclear reactor is often limited by the

460

Reactor hot spot analysis  

SciTech Connect

The principle methods for performing reactor hot spot analysis are reviewed and examined for potential use in the Applied Physics Division. The semistatistical horizontal method is recommended for future work and is now available as an option in the SE2-ANL core thermal hydraulic code. The semistatistical horizontal method is applied to a small LMR to illustrate the calculation of cladding midwall and fuel centerline hot spot temperatures. The example includes a listing of uncertainties, estimates for their magnitudes, computation of hot spot subfactor values and calculation of two sigma temperatures. A review of the uncertainties that affect liquid metal fast reactors is also presented. It was found that hot spot subfactor magnitudes are strongly dependent on the reactor design and therefore reactor specific details must be carefully studied. 13 refs., 1 fig., 5 tabs.

Vilim, R.B.

1985-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Methods for quantifying uncertainty in fast reactor analyses.  

SciTech Connect

Liquid-metal-cooled fast reactors in the form of sodium-cooled fast reactors have been successfully built and tested in the U.S. and throughout the world. However, no fast reactor has operated in the U.S. for nearly fourteen years. More importantly, the U.S. has not constructed a fast reactor in nearly 30 years. In addition to reestablishing the necessary industrial infrastructure, the development, testing, and licensing of a new, advanced fast reactor concept will likely require a significant base technology program that will rely more heavily on modeling and simulation than has been done in the past. The ability to quantify uncertainty in modeling and simulations will be an important part of any experimental program and can provide added confidence that established design limits and safety margins are appropriate. In addition, there is an increasing demand from the nuclear industry for best-estimate analysis methods to provide confidence bounds along with their results. The ability to quantify uncertainty will be an important component of modeling that is used to support design, testing, and experimental programs. Three avenues of UQ investigation are proposed. Two relatively new approaches are described which can be directly coupled to simulation codes currently being developed under the Advanced Simulation and Modeling program within the Reactor Campaign. A third approach, based on robust Monte Carlo methods, can be used in conjunction with existing reactor analysis codes as a means of verification and validation of the more detailed approaches.

Fanning, T. H.; Fischer, P. F.

2008-04-07T23:59:59.000Z

462

Molten metal reactors  

DOE Patents (OSTI)

A molten metal reactor for converting a carbon material and steam into a gas comprising hydrogen, carbon monoxide, and carbon dioxide is disclosed. The reactor includes an interior crucible having a portion contained within an exterior crucible. The interior crucible includes an inlet and an outlet; the outlet leads to the exterior crucible and may comprise a diffuser. The exterior crucible may contain a molten alkaline metal compound. Contained between the exterior crucible and the interior crucible is at least one baffle.

Bingham, Dennis N; Klingler, Kerry M; Turner, Terry D; Wilding, Bruce M

2013-11-05T23:59:59.000Z

463

F Reactor Inspection  

ScienceCinema (OSTI)

Workers from Mission Support Alliance, LLC., removed the welds around the steel door of the F Reactor before stepping inside the reactor to complete its periodic inspection. This is the first time the Department of Energy (DOE) has had the reactor open since 2008. The F Reactor is one of nine reactors along the Columbia River at the Department's Hanford Site in southeastern Washington State, where environmental cleanup has been ongoing since 1989. As part of the Tri-Party Agreement, the Department completes surveillance and maintenance activities of cocooned reactors periodically to evaluate the structural integrity of the safe storage enclosure and to ensure confinement of any remaining hazardous materials. "This entry marks a transition of sorts because the Hanford Long-Term Stewardship Program, for the first time, was responsible for conducting the entry and surveillance and maintenance activities," said Keith Grindstaff, Energy Department Long-Term Stewardship Program Manager. "As the River Corridor cleanup work is completed and transitioned to long-term stewardship, our program will manage any on-going requirements."

Grindstaff, Keith; Hathaway, Boyd; Wilson, Mike

2014-11-24T23:59:59.000Z

464

F Reactor Inspection  

SciTech Connect

Workers from Mission Support Alliance, LLC., removed the welds around the steel door of the F Reactor before stepping inside the reactor to complete its periodic inspection. This is the first time the Department of Energy (DOE) has had the reactor open since 2008. The F Reactor is one of nine reactors along the Columbia River at the Department's Hanford Site in southeastern Washington State, where environmental cleanup has been ongoing since 1989. As part of the Tri-Party Agreement, the Department completes surveillance and maintenance activities of cocooned reactors periodically to evaluate the structural integrity of the safe storage enclosure and to ensure confinement of any remaining hazardous materials. "This entry marks a transition of sorts because the Hanford Long-Term Stewardship Program, for the first time, was responsible for conducting the entry and surveillance and maintenance activities," said Keith Grindstaff, Energy Department Long-Term Stewardship Program Manager. "As the River Corridor cleanup work is completed and transitioned to long-term stewardship, our program will manage any on-going requirements."

Grindstaff, Keith; Hathaway, Boyd; Wilson, Mike

2014-10-29T23:59:59.000Z

465

Reactor Safety Research Programs Quarterly Report October - December 1981  

SciTech Connect

This document summarizes the work performed by Pacific Northwest laboratory (PNL) from October 1 through December 31, 1981, for the Division of Accident Evaluation, 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 serviceinduced 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 post accident 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), Idaho Falls, Idaho. These programs will provide data for computer modeling of reactor system and fuel performance during various abnormal operating conditions.

Edler, S. K.

1982-03-01T23:59:59.000Z

466

Computational Nuclear Forensics Analysis of Weapons-grade Plutonium Separated from Fuel Irradiated in a Thermal Reactor  

E-Print Network (OSTI)

have been irradiated to the desired burnup in the Oak Ridge National Laboratory- High Flux Isotope Reactor (ORNL-HFIR), and then separated using the PUREX process to experimentally determine the intrinsic signature of the fuel. The experimental data...

Coles, Taylor Marie

2014-04-27T23:59:59.000Z

467

IN TODAY'S PAPER International  

E-Print Network (OSTI)

India's participation in the multi-billion-dollar International Thermonuclear Reactor project which aims

468

REACTOR GROUT THERMAL PROPERTIES  

SciTech Connect

Savannah River Site has five dormant nuclear production reactors. Long term disposition will require filling some reactor buildings with grout up to ground level. Portland cement based grout will be used to fill the buildings with the exception of some reactor tanks. Some reactor tanks contain significant quantities of aluminum which could react with Portland cement based grout to form hydrogen. Hydrogen production is a safety concern and gas generation could also compromise the structural integrity of the grout pour. Therefore, it was necessary to develop a non-Portland cement grout to fill reactors that contain significant quantities of aluminum. Grouts generate heat when they set, so the potential exists for large temperature increases in a large pour, which could compromise the integrity of the pour. The primary purpose of the testing reported here was to measure heat of hydration, specific heat, thermal conductivity and density of various reactor grouts under consideration so that these properties could be used to model transient heat transfer for different pouring strategies. A secondary purpose was to make qualitative judgments of grout pourability and hardened strength. Some reactor grout formulations were unacceptable because they generated too much heat, or started setting too fast, or required too long to harden or were too weak. The formulation called 102H had the best combination of characteristics. It is a Calcium Alumino-Sulfate grout that contains Ciment Fondu (calcium aluminate cement), Plaster of Paris (calcium sulfate hemihydrate), sand, Class F fly ash, boric acid and small quantities of additives. This composition afforded about ten hours of working time. Heat release began at 12 hours and was complete by 24 hours. The adiabatic temperature rise was 54 C which was within specification. The final product was hard and displayed no visible segregation. The density and maximum particle size were within specification.

Steimke, J.; Qureshi, Z.; Restivo, M.; Guerrero, H.

2011-01-28T23:59:59.000Z

469

Reactor Safety Planning for Prometheus Project, for Naval Reactors Information  

SciTech Connect

The purpose of this letter is to submit to Naval Reactors the initial plan for the Prometheus project Reactor Safety work. The Prometheus project is currently developing plans for cold physics experiments and reactor prototype tests. These tests and facilities may require safety analysis and siting support. In addition to the ground facilities, the flight reactor units will require unique analyses to evaluate the risk to the public from normal operations and credible accident conditions. This letter outlines major safety documents that will be submitted with estimated deliverable dates. Included in this planning is the reactor servicing documentation and shipping analysis that will be submitted to Naval Reactors.

P. Delmolino

2005-05-06T23:59:59.000Z

470

B Reactor | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Operational Management » History » Manhattan Project » Signature Operational Management » History » Manhattan Project » Signature Facilities » B Reactor B Reactor B Reactor Completed in September 1944, the B Reactor was the world's first large-scale plutonium production reactor. As at Oak Ridge, the need for labor turned Hanford into an atomic boomtown, with the population reaching 50,000 by summer 1944. Similar to the X-10 Graphite Reactor at Oak Ridge in terms of loading and unloading fuel, the B Reactor was built on a much larger scale and used water rather than air as a coolant. Whereas the X-10 had an initial design output of 1,000 kilowatts, the B Reactor was designed to operate at 250,000 kilowatts. Consisting of a 28- by 36-foot, 1,200-ton graphite cylinder lying on its side, the reactor was penetrated through its

471

Reactor Pressure Vessel Task of Light Water Reactor Sustainability Program:  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Reactor Pressure Vessel Task of Light Water Reactor Sustainability Reactor Pressure Vessel Task of Light Water Reactor Sustainability Program: Initial Assessment of Thermal Annealing Needs and Challenges Reactor Pressure Vessel Task of Light Water Reactor Sustainability Program: Initial Assessment of Thermal Annealing Needs and Challenges The most life-limiting structural component in light-water reactors (LWR) is the reactor pressure vessel (RPV) because replacement of the RPV is not considered a viable option at this time. LWR licenses are now being extended from 40y to 60y by the U.S. Nuclear Regulatory Commission (NRC) with intentions to extend licenses to 80y and beyond. The RPV materials exhibit varying degrees of sensitivity to irradiation-induced embrittlement (decreased toughness) , as shown in Fig. 1.1, and extending operation from

472

Reactor Pressure Vessel Task of Light Water Reactor Sustainability Program:  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Reactor Pressure Vessel Task of Light Water Reactor Sustainability Reactor Pressure Vessel Task of Light Water Reactor Sustainability Program: Milestone Report on Materials and Machining of Specimens for the ATR-2 Experiment Reactor Pressure Vessel Task of Light Water Reactor Sustainability Program: Milestone Report on Materials and Machining of Specimens for the ATR-2 Experiment The reactor pressure vessel (RPV) in a light-water reactor (LWR) represents the first line of defense against a release of radiation in case of an accident. Thus, regulations, which govern the operation of commercial nuclear power plants, require conservative margins of fracture toughness, both during normal operation and under accident scenarios. In the unirradiated condition, the RPV has sufficient fracture toughness such that failure is implausible under any postulated condition, including

473

Reactor for exothermic reactions  

DOE Patents (OSTI)

A liquid phase process is described for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

Smith, L.A. Jr.; Hearn, D.; Jones, E.M. Jr.

1993-03-02T23:59:59.000Z

474

Thermionic Reactor Design Studies  

SciTech Connect

Paper presented at the 29th IECEC in Monterey, CA in August 1994. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their (thermionic reactor) performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling.

Schock, Alfred

1994-08-01T23:59:59.000Z

475

Diagnostics for hybrid reactors  

SciTech Connect

The Hybrid Reactor(HR) can be considered an attractive actinide-burner or a fusion assisted transmutation for destruction of transuranic(TRU) nuclear waste. The hybrid reactor has two important subsystems: the tokamak neutron source and the blanket which includes a fuel zone where the TRU are placed and a tritium breeding zone. The diagnostic system for a HR must be as simple and robust as possible to monitor and control the plasma scenario, guarantee the protection of the machine and monitor the transmutation.

Orsitto, Francesco Paolo [ENEA Unita' Tecnica Fusione , Associazione ENEA-EURATOM sulla Fusione C R Frascati v E Fermi 45 00044 Frascati (Italy)

2012-06-19T23:59:59.000Z

476

Structural materials for fusion reactors  

Science Journals Connector (OSTI)

Fusion Reactors will require specially engineered structural materials, which ... on safety considerations. The fundamental differences between fusion and other nuclear reactors arise due to the 14MeV neutronics ...

P. M. Raole; S. P. Deshpande

2009-04-01T23:59:59.000Z

477

A model for waterside oxidation of zircaloy fuel cladding in pressurized water reactors  

SciTech Connect

A model is developed to simulate the oxidation of zircaloy fuel rod cladding exposed to pressurized water reactor operating conditions. The model is used to predict the oxidation rate for both ex- and in-reactor conditions in terms of the weight gain and oxide thickness. Comparisons of the model predictions with experimental data show very good agreement.

Amarshad, A.I.A. [Institute of Atomic Energy Research, Riyadh (Saudi Arabia); Klein, A.C. [Oregon State Univ., Corvallis, OR (United States)

1992-12-31T23:59:59.000Z

478

Reactor Materials | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Benefits Crosscutting Technology Development Reactor Materials Advanced Sensors and Instrumentation Proliferation and Terrorism Risk Assessment Advanced Methods for Manufacturing...

479

Reactor operation safety information document  

SciTech Connect

The report contains a reactor facility description which includes K, P, and L reactor sites, structures, operating systems, engineered safety systems, support systems, and process and effluent monitoring systems; an accident analysis section which includes cooling system anomalies, radioactive materials releases, and anticipated transients without scram; a summary of onsite doses from design basis accidents; severe accident analysis (reactor core disruption); a description of operating contractor organization and emergency planning; and a summary of reactor safety evolution. (MB)

Not Available

1990-01-01T23:59:59.000Z

480

RECENT PROGRESS IN HEAVY ION SOURCES  

E-Print Network (OSTI)

improved Bevalac Fusion reactors Vi Q) U .c. Laser, expl.into thermonuclear fusion reactors. A summary of ion sources

Clark, D.J.

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermonuclear experimental reactor" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Fossil fuel furnace reactor  

DOE Patents (OSTI)

A fossil fuel furnace reactor is provided for simulating a continuous processing plant with a batch reactor. An internal reaction vessel contains a batch of shale oil, with the vessel having a relatively thin wall thickness for a heat transfer rate effective to simulate a process temperature history in the selected continuous processing plant. A heater jacket is disposed about the reactor vessel and defines a number of independent controllable temperature zones axially spaced along the reaction vessel. Each temperature zone can be energized to simulate a time-temperature history of process material through the continuous plant. A pressure vessel contains both the heater jacket and the reaction vessel at an operating pressure functionally selected to simulate the continuous processing plant. The process yield from the oil shale may be used as feedback information to software simulating operation of the continuous plant to provide operating parameters, i.e., temperature profiles, ambient atmosphere, operating pressure, material feed rates, etc., for simulation in the batch reactor.

Parkinson, William J. (Los Alamos, NM)

1987-01-01T23:59:59.000Z

482

Transport reactor development status  

SciTech Connect

This project is part of METC`s Power Systems Development Facility (PSDF) located at Wilsonville, Alabama. The primary objective of the Advanced Gasifier module is to produce vitiated gases for intermediate-term testing of Particulate Control Devices (PCDs). The Transport reactor potentially allows particle size distribution, solids loading, and particulate characteristics in the off-gas stream to be varied in a number of ways. Particulates in the hot gases from the Transport reactor will be removed in the PCDs. Two PCDs will be initially installed in the module; one a ceramic candle filter, the other a granular bed filter. After testing of the initial PCDs they will be removed and replaced with PCDs supplied by other vendors. A secondary objective is to verify the performance of a Transport reactor for use in advanced Integrated Gasification Combined Cycle (IGCC), Integrated Gasification Fuel Cell (IG-FC), and Pressurized Combustion Combined Cycle (PCCC) power generation units. This paper discusses the development of the Transport reactor design from bench-scale testing through pilot-scale testing to design of the Process Development Unit (PDU-scale) facility at Wilsonville.

Rush, R.E.; Fankhanel, M.O.; Campbell, W.M.

1994-10-01T23:59:59.000Z

483

Thermal Reactor Safety  

SciTech Connect

Information is presented concerning fire risk and protection; transient thermal-hydraulic analysis and experiments; class 9 accidents and containment; diagnostics and in-service inspection; risk and cost comparison of alternative electric energy sources; fuel behavior and experiments on core cooling in LOCAs; reactor event reporting analysis; equipment qualification; post facts analysis of the TMI-2 accident; and computational methods.

Not Available

1980-06-01T23:59:59.000Z

484

NETL - Chemical Looping Reactor  

ScienceCinema (OSTI)

NETL's Chemical Looping Reactor unit is a high-temperature integrated CLC process with extensive instrumentation to improve computational simulations. A non-reacting test unit is also used to study solids flow at ambient temperature. The CLR unit circulates approximately 1,000 pounds per hour at temperatures around 1,800 degrees Fahrenheit.

None

2014-06-26T23:59:59.000Z

485

System and method for generating steady state confining current for a toroidal plasma fusion reactor  

DOE Patents (OSTI)

A system for generating steady state confining current for a toroidal plasma fusion reactor providing steady-state generation of the thermonuclear power. A dense, hot toroidal plasma is initially prepared with a confining magnetic field with toroidal and poloidal components. Continuous wave RF energy is injected into said plasma to establish a spectrum of traveling waves in the plasma, where the traveling waves have momentum components substantially either all parallel, or all anti-parallel to the confining magnetic field. The injected RF energy is phased to couple to said traveling waves with both a phase velocity component and a wave momentum component in the direction of the plasma traveling wave components. The injected RF energy has a predetermined spectrum selected so that said traveling waves couple to plasma electrons having velocities in a predetermined range .DELTA.. The velocities in the range are substantially greater than the thermal electron velocity of the plasma. In addition, the range is sufficiently broad to produce a raised plateau having width .DELTA. in the plasma electron velocity distribution so that the plateau electrons provide steady-state current to generate a poloidal magnetic field component sufficient for confining the plasma. In steady state operation of the fusion reactor, the fusion power density in the plasma exceeds the power dissipated in the plasma.

Fisch, Nathaniel J. (Cambridge, MA)

1981-01-01T23:59:59.000Z

486

System and method for generating steady state confining current for a toroidal plasma fusion reactor  

DOE Patents (OSTI)

A system for generating steady state confining current for a toroidal plasma fusion reactor providing steady-state generation of the thermonuclear power. A dense, hot toroidal plasma is initially prepared with a confining magnetic field with toroidal and poloidal components. Continuous wave RF energy is injected into said plasma to estalish a spectrum of traveling waves in the plasma, where the traveling waves have momentum components substantially either all parallel, or all anti-parallel to the confining magnetic field. The injected RF energy is phased to couple to said traveling waves with both a phase velocity component and a wave momentum component in the direction of the plasma traveling wave components. The injected RF energy has a predetermined spectrum selected so that said traveling waves couple to plasma electrons having velocities in a predetermined range .DELTA.. The velocities in the range are substantially greater than the thermal electron velocity of the plasma. In addition, the range is sufficiently broad to produce a raised plateau having width .DELTA. in the plasma electron velocity distribution so that the plateau electrons provide steady-state current to generate a poloidal magnetic field component sufficient for confining the plasma. In steady state operation of the fusion reactor, the fusion power density in the plasma exceeds the power dissipated inthe plasma.

Bers, Abraham (Arlington, MA)

1981-01-01T23:59:59.000Z

487

Mixing in Unbaffled High-Throughput Experimentation Reactors  

Science Journals Connector (OSTI)

Use of unbaffled vessels is essential because of the automation of the unit responsible for loading, sampling, discharging, and cleaning the vessel; such tasks are easier for a robot to perform on unbaffled vessels because material can be trapped around baffle plates, especially when viscous materials are involved. ... The impellers were painted with matte black paint to prevent reflection of incident laser radiation and also to seal the impeller surface. ...

Jonathan F. Hall; Mostafa Barigou; Mark J. H. Simmons; E. Hugh Stitt

2004-06-09T23:59:59.000Z

488

NUCLEAR MATERIALS RESEARCH PROGRESS REPORTS FOR 1979  

E-Print Network (OSTI)

Chemical E f f e c t s of Thermonuclear Plasma I n t e r a cfor Controlled Thermonuclear Reactor (CTR), USAEC Report LA

Olander, D.R.

2010-01-01T23:59:59.000Z

489

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

E-Print Network (OSTI)

conditions for thermonuclear burn in fusion reactors is theFusion Energy (LIFE) Engine The transition from demonstrating thermonuclearfusion being well understood, the confinement conditions required for thermonuclear

Holdener, Dain Steffen

2011-01-01T23:59:59.000Z

490

RECENT PROGRESS IN HEAVY ION SOURCES  

E-Print Network (OSTI)

of hydrogen into thermonuclear fusion reactors. A summary ofFusion Plasma Sources Other sources of high charge state ions include the dense plasma in magnetic confinement thermonuclear

Clark, D.J.

2010-01-01T23:59:59.000Z

491

Losses of heat and particles in the presence of strong magnetic field perturbations.  

E-Print Network (OSTI)

??Thermonuclear fusion has potential to offer an economically, environmentally and socially acceptable supply of energy. A promising reactor design to execute thermonuclear fusion is the… (more)

gupta, abhinav

2009-01-01T23:59:59.000Z

492

Design, construction and evaluation of a facility for the simulation of fast reactor blankets  

E-Print Network (OSTI)

A facility has been designed and constructed at the MIT Reactor for the experimental investigation of typical LMFBR breeding blankets. A large converter assembly, consisting of a 20-cm-thick layer of graphite followed by ...

Forbes, Ian Alexander

1970-01-01T23:59:59.000Z

493

A review of experiments and results from the transient reactor test (TREAT) facility.  

SciTech Connect

The TREAT Facility was designed and built in the late 1950s at Argonne National Laboratory to provide a transient reactor for safety experiments on samples of reactor fuels. It first operated in 1959. Throughout its history, experiments conducted in TREAT have been important in establishing the behavior of a wide variety of reactor fuel elements under conditions predicted to occur in reactor accidents ranging from mild off normal transients to hypothetical core disruptive accidents. For much of its history, TREAT was used primarily to test liquid-metal reactor fuel elements, initially for the Experimental Breeder Reactor-II (EBR-II), then for the Fast Flux Test Facility (FFTF), the Clinch River Breeder Reactor Plant (CRBRP), the British Prototype Fast Reactor (PFR), and finally, for the Integral Fast Reactor (IFR). Both oxide and metal elements were tested in dry capsules and in flowing sodium loops. The data obtained were instrumental in establishing the behavior of the fuel under off-normal and accident conditions, a necessary part of the safety analysis of the various reactors. In addition, TREAT was used to test light-water reactor (LWR) elements in a steam environment to obtain fission-product release data under meltdown conditions. Studies are now under way on applications of TREAT to testing of the behavior of high-burnup LWR elements under reactivity-initiated accident (RIA) conditions using a high-pressure water loop.

Deitrich, L. W.

1998-07-28T23:59:59.000Z

494

Reactor vessel support system. [LMFBR  

DOE Patents (OSTI)

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.

Golden, M.P.; Holley, J.C.

1980-05-09T23:59:59.000Z

495

Fusion reactor systems  

Science Journals Connector (OSTI)

In this review we consider deuterium-tritium (D-T) fusion reactors based on four different plasma-confinement and heating approaches: the tokamak, the theta-pinch, the magnetic-mirror, and the laser-pellet system. We begin with a discussion of the dynamics of reacting plasmas and basic considerations of reactor power balance. The essential plasma physical aspects of each system are summarized, and the main characteristics of the corresponding conceptual power plants are described. In tokamak reactors the plasma densities are about 1020 m-3, and the ? values (ratio of plasma pressure to confining magnetic pressure) are approximately 5%. Plasma burning times are of the order of 100-1000 sec. Large superconducting dc magnets furnish the toroidal magnetic field, and 2-m thick blankets and shields prevent heat deposition in the superconductor. Radially diffusing plasma is diverted away from the first wall by means of null singularities in the poloidal (or transverse) component of the confining magnetic field. The toroidal theta-pinch reactor has a much smaller minor diameter and a much larger major diameter, and operates on a 10-sec cycle with 0.1-sec burning pulses. It utilizes shock heating from high-voltage sources and adabatic-compression heating powered by low-voltage, pulsed cryogenic magnetic or inertial energy stores, outside the reactor core. The plasma has a density of about 1022 m-3 and ? values of nearly unity. In the power balance of the reactor, direct-conversion energy obtained by expansion of the burning high-? plasma against the containing magnetic field is an important factor. No divertor is necessary since neutral-gas flow cools and replaces the "spent" plasma between pulses. The open-ended mirror reactor uses both thermal conversion of neutron energy and direct conversion of end-loss plasma energy to dc electrical power. A fraction of this direct-convertor power is then fed back to the ioninjection system to sustain the reaction and maintain the plasma. The average ion energy is 600 keV, plasma diameter 6 m, and the plasma beta 85%. The power levels of the three magnetic-confinement devices are in the 500-2000 MWe range, with the exception of the mirror reactor, for which the output is approximately 200 MWe. In Laser-Pellet reactors, frozen D-T pellets are ignited in a cavity which absorbs the electromagnetic, charged particle, and neutron energy from the fusion reaction. The confinement is "inertial," since the fusion reaction occurs during the disassembly of the heated pellet. A pellet-cavity unit would produce about 200 MWt in pulses with a repetition rate of the order of 10 sec-1. Such units could be clustered to give power plants with outputs in the range of 1000 MWe.

F. L. Ribe

1975-01-01T23:59:59.000Z

496

Direct-Drive Inerital Confinement Fusion Research at the Laboratory for Laser Energetics: Charting the Path to Thermonuclear Ignition  

SciTech Connect

Significant theoretical and experimental progress continues to be made at the University of Rocheter's Laboratory for Laser Energetics (LLE), charting the path to direct-drive inertial confinement fusion (ICF) ignition. Direct drive offers the potential for higher-gain implosions than x-ray drive and is a leading candidate for an inertial fusion enery power plant.

McCrory, R.L.; Regan, S.P.; Loucks, S.J.; Meyerhofer, D.D.; Skupsky, S.; Betti, R.; Boehly, T.R.; Craxton, R.S.; Collins, T.J.B.; Delettrez, J.A.; Edgell, D.; Epstein, R.; Fletcher, K.A.; Freeman, C.; Frenje, J.A.; Glebov, V.Yu.; Goncharov, V.N.; Harding, D.R.; Igumenshchev, I.V.; Keck, R.L.; Kilkenny, J.D.; Knauer, J.P.; Li, C.K.; Marciante, J.; Marozas, J.A.; Marshall, F.J.; Maximov, A.V.; McKenty, P.W.; Myatt, J.; Padalino, S.; Petrasso, R.D.; Radha, P.B.; Sangster, T.C.; Seguin, F.H.; Seka, W.; Smalyuk, V.A.; Soures, J.M.; Stoeckl, C.; Yaakobi, B.; Zuegel, J.D.

2005-10-07T23:59:59.000Z

497

Polarized neutron reflectometry at the IBR-2 pulsed reactor  

SciTech Connect

Polarized neutron reflectometry as a method for investigating layered nanostructures and its implementation at the IBR-2 pulsed reactor (Dubna, Russia) are described. The experimental data illustrating the studies of magnetic layered nanostructures and the development of the method of polarized neutron reflectometry on the polarized neutron spectrometer are presented. The directions of further development of the method of polarized neutron reflectometry are analyzed.

Aksenov, V. L. [Russian Research Centre 'Kurchatov Institute' (Russian Federation); Nikitenko, Yu. V. [Joint Institute for Nuclear Research (Russian Federation)], E-mail: nikiten@nf.jinr.ru

2007-05-15T23:59:59.000Z

498

Benchmark Evaluation of the NRAD Reactor LEU Core Startup Measurements  

SciTech Connect

The Neutron Radiography (NRAD) reactor is a 250-kW TRIGA-(Training, Research, Isotope Production, General Atomics)-conversion-type reactor at the Idaho National Laboratory; it is primarily used for neutron radiography analysis of irradiated and unirradiated fuels and materials. The NRAD reactor was converted from HEU to LEU fuel with 60 fuel elements and brought critical on March 31, 2010. This configuration of the NRAD reactor has been evaluated as an acceptable benchmark experiment and is available in the 2011 editions of the International Handbook of Evaluated Criticality Safety Benchmark Experiments (ICSBEP Handbook) and the International Handbook of Evaluated Reactor Physics Benchmark Experiments (IRPhEP Handbook). Significant effort went into precisely characterizing all aspects of the reactor core dimensions and material properties; detailed analyses of reactor parameters minimized experimental uncertainties. The largest contributors to the total benchmark uncertainty were the 234U, 236U, Er, and Hf content in the fuel; the manganese content in the stainless steel cladding; and the unknown level of water saturation in the graphite reflector blocks. A simplified benchmark model of the NRAD reactor was prepared with a keff of 1.0012 {+-} 0.0029 (1s). Monte Carlo calculations with MCNP5 and KENO-VI and various neutron cross section libraries were performed and compared with the benchmark eigenvalue for the 60-fuel-element core configuration; all calculated eigenvalues are between 0.3 and 0.8% greater than the benchmark value. Benchmark evaluations of the NRAD reactor are beneficial in understanding biases and uncertainties affecting criticality safety analyses of storage, handling, or transportation applications with LEU-Er-Zr-H fuel.

J. D. Bess; T. L. Maddock; M. A. Marshall

2011-09-01T23:59:59.000Z

499

Nuclear reactor construction with bottom supported reactor vessel  

DOE Patents (OSTI)

An improved liquid metal nuclear reactor construction has a reactor core and a generally cylindrical reactor vessel for holding a large pool of low pressure liquid metal coolant and housing the core within the pool. The reactor vessel has an open top end, a closed flat bottom end wall and a continuous cylindrical closed side wall interconnecting the top end and bottom end wall. The reactor also has a generally cylindrical concrete containment structure surrounding the reactor vessel and being formed by a cylindrical side wall spaced outwardly from the reactor vessel side wall and a flat base mat spaced below the reactor vessel bottom end wall. A central support pedestal is anchored to the containment structure base mat and extends upwardly therefrom to the reactor vessel and upwardly therefrom to the reactor core so as to support the bottom end wall of the reactor vessel and the lower end of the reactor core in spaced apart relationship above the containment structure base mat. Also, an annular reinforced support structure is disposed in the reactor vessel on the bottom end wall thereof and extends about the lower end of the core so as to support the periphery thereof. In addition, an annular support ring having a plurality of inward radially extending linear members is disposed between the containment structure base mat and the bottom end of the reactor vessel wall and is connected to and supports the reactor vessel at its bottom end on the containment structure base mat so as to allow the reactor vessel to expand radially but substantially prevent any lateral motions that might be imposed by the occurrence of a seismic event. The reactor construction also includes a bed of insulating material in sand-like granular form, preferably being high density magnesium oxide particles, disposed between the containment structure base mat and the bottom end wall of the reactor vessel and uniformly supporting the reactor vessel at its bottom end wall on the containment structure base mat so as to insulate the reactor vessel bottom end wall from the containment structure base mat and allow the reactor vessel bottom end wall to freely expand as it heats up while providing continuous support thereof. Further, a deck is supported upon the side wall of the containment structure above the top open end of the reactor vessel, and a plurality of serially connected extendible and retractable annular bellows extend between the deck and the top open end of the reactor vessel and flexibly and sealably interconnect the reactor vessel at its top end to the deck. An annular guide ring is disposed on the containment structure and extends between its side wall and the top open end of the reactor vessel for providing lateral support of the reactor vessel top open end by limiting imposition of lateral loads on the annular bellows by the occurrence of a lateral seismic event.

Sharbaugh, John E. (Bullskin Township, Fayette County, PA)

1987-01-01T23:59:59.000Z

500

Spherical torus fusion reactor  

DOE Patents (OSTI)

A fusion reactor is provided having a near spherical-shaped plasma with a modest central opening through which straight segments of toroidal field coils extend that carry electrical current for generating a toroidal magnet plasma confinement fields. By retaining only the indispensable components inboard of the plasma torus, principally the cooled toroidal field conductors and in some cases a vacuum containment vessel wall, the fusion reactor features an exceptionally small aspect ratio (typically about 1.5), a naturally elongated plasma cross section without extensive field shaping, requires low strength magnetic containment fields, small size and high beta. These features combine to produce a spherical torus plasma in a unique physics regime which permits compact fusion at low field and modest cost.

Peng, Yueng-Kay M. (Oak Ridge, TN)

1989-01-01T23:59:59.000Z