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AbstractAbstract
[en] The theory of spectral lines in a plasma with quasistatic ions is reconsidered. The ion microfield distribution, generalized to include field gradients and higher-order derivatives, is introduced without decoupling the ion and electron subsystems. It is shown that in a self-consistent treatment of ion-electron correlations the calculations of line shifts requires a more complete theory than has been used in the past. It is shown that level shifts due to a time average of the radiator-plasma interaction are closely related to shifts due to ion field inhomogeneities at the radiator. These two shifting mechanisms are not independent and the analysis indicates how to avoid overcounting. As a result, the time average of the radiator-plasma interaction, usually associated with the so-called plasma polarization shift, is formally different from the equivalent expression given by theories which treat electron-ion correlations in an ad hoc fashion. 14 references
Primary Subject
Record Type
Journal Article
Journal
Physical Review. B, Solid State; ISSN 0556-2805;
; v. 29 p. 1366-1370

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Leclercq, J.
Fragema, 69 - Lyon (France)1986
Fragema, 69 - Lyon (France)1986
AbstractAbstract
[en] The fuel assembly comprises a structure made of two end pieces connected by long elements and several grids arranged along the guide tubes and forming cells to maintain the fuel rods. The grids include median grilles, designed to support lateral shocks and provided with fins to create turbulence in the coolant flow along the assembly, lower grilles without fins and ensuring rod bracing, upper grilles provided with fins and ensuring rod bracing, the upper and lower grilles inducing a lower loss of flow than the median grilles. The invention has an important application in light-water reactors with spectral shift control
[fr]
L'assemblage comprend un squelette comportant deux pieces d'extremite reliees par des elements allonges et plusieurs grilles reparties le long des tubes guides et formant des cellules de maintien d'un faisceau de crayons de combustible aux noeuds d'un reseau regulier. Les grilles comportent des grilles medianes concues de facon a resister aux chocs lateraux et munies d'ailettes de creation de turbulences dans l'ecoulement du refrigerant le long de l'assemblage, des grilles basses demunies d'ailettes et assurant l'entretoisement des crayons et des grilles hautes munies d'ailettes et assurant l'entretoisement des crayons, les grilles hautes et basses imposant au refrigerant une perte de charge plus faible que les grilles medianes. L'invention trouve une application particulierement importante dans les reacteurs a eau legere du type dit ''a variation de spectre''Original Title
Assemblage de combustible pour reacteur nucleaire
Primary Subject
Secondary Subject
Source
13 Jun 1986; 6 Dec 1984; 27 p; FR PATENT DOCUMENT 2574579/A/; FR PATENT APPLICATION 8418645; Available from Institut National de la Propriete Industrielle, Paris (France); Application date: 6 Dec 1984
Record Type
Patent
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Millot, J.P.; Desfontaines, G.; Babin, M.
Societe Franco-Americaine de Constructions Atomiques (FRAMATOME), 92 - Courbevoie (France)1984
Societe Franco-Americaine de Constructions Atomiques (FRAMATOME), 92 - Courbevoie (France)1984
AbstractAbstract
[en] The first rod cluster used to control the reactor is connected to a first drive shaft which is moved by a mechanism; this drive shaft comprises locking thimbles which are actionned by a device sliding on the end of the shaft; this device ensures the locking of thimbles by means of a spring or their opening moving to the top of the shaft. The second cluster, keeping inserted completely in the assembly during a part of the reactor operation cycle, is connected to a second drive shaft. This second shaft mounted coaxialy inside the first shaft, acts as a piston actionned for its displacement to the top by the opening a pressure reducing valve of the tight shell in which the two drive shafts move. The second shaft, in high position, can be connected to the first one by the thimbles fitting into a groove of the second drive shaft. The invention applies, more particularly, to nuclear reactor with improved efficiency utilizing neutron spectra shift control clusters
[fr]
La premiere grappe servant au pilotage du reacteur est reliee a une premiere tige de commande dont les mouvements sont assures par un mecanisme. Cette tige porte des doigts d'accrochage dont l'actionnement est assure par un dispositif monte coulissant sur l'extremite de la tige. Le dispositif assure la fermeture des doigts grace a un ressort ou au contraire leur ouverture par mouvement en sur-course vers le haut de la tige. La seconde grappe restant inseree completement dans l'assemblage pendant une partie du cycle de fonctionnement du reacteur est reliee a une seconde tige de commande. Cette seconde tige montee coaxialement a l'interieur de la tige constitue un piston dans cette tige actionne pour son mouvement vers le haut par ouverture d'une vanne de decompression de l'enceinte etanche dans laquelle se deplacent les tiges de commande et la tige en position haute peut etre reliee a la tige par les doigts s'engageant dans une rainure de la tige. L'invention s'applique, en particulier, aux reacteurs nucleaires a rendement ameliore utilisant des grappes de variation de spectre neutroniqueOriginal Title
Dispositif de commande de deux grappes de crayons de reglage deplacables verticalement dans un meme assemblage combustible du coeur d'un reacteur nucleaire
Primary Subject
Source
15 Jun 1984; 8 Dec 1982; 20 p; FR PATENT DOCUMENT 2537764/A/; FR PATENT APPLICATION 8220543; Available from Institut National de la Propriete Industrielle, Paris (France); Application date: 8 Dec 1982
Record Type
Patent
Country of publication
Reference NumberReference Number
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Matzie, R.A.; Sider, F.M.
Combustion Engineering, Inc., Windsor, CT (USA)1979
Combustion Engineering, Inc., Windsor, CT (USA)1979
AbstractAbstract
[en] The performance of the spectral shift controlled reactor (SSCR) operating on uranium fuel cycles was evaluated and compared with the conventional pressurized water reactor (PWR). In order to analyze the SSCR, the PSR design methodology was extended to include systems moderated by mixtures of light water and heavy water and these methods were validated by comparison with experimental results. Once the design methods had been formulated, the resouce requirements and power costs were determined for the uranium-fueled SSCR. The ore requirements of the UO2 once-through fuel cycle and the UO2 fuel cycle with self-generated recycle (SGR) of plutonium were found to be 10% and 19% less than those of similarly fueled PWRs, respectively. A fuel cycle optimization study was performed for the UO2 once-through SSCR and the SGR SSCR. By individually altering lattice parameters, discharge exposure or number of in-core batches, savings of less than 8% in resource requirements and less than 1% in power costs were obtained
Primary Subject
Source
Aug 1979; 257 p; Available from NTIS., PC A12/MF A01
Record Type
Report
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Chabanov, V.M.; Zakhariev, B.N.
International conference on nuclear physics. Summaries of reports1998
International conference on nuclear physics. Summaries of reports1998
AbstractAbstract
No abstract available
Primary Subject
Source
Gromov, K.Ya. (ed.) (OIYaI, Dubna (Russian Federation)); Russian Academy of Sciences, Moscow (Russian Federation); Ministry of Russian Federation for Atomic Energy, Moscow (Russian Federation); Ministry of Russian Federation on Science and Technology, Moscow (Russian Federation); Peoples' Friendship University of Russia, Moscow (Russian Federation); Joint Institute for Nuclear Research, Dubna (Russian Federation); Petersburg Nuclear Physics Institute, Sankt-Peterburg (Russian Federation); 445 p; ISBN 5-86763-121-4;
; 1998; p. 152; 48. Meeting on nuclear spectroscopy and structure of atomic nucleus; 48. Soveshchanie po yadernoj spektroskopii i strukture atomnogo yadra; Moscow (Russian Federation); 16-18 Jun 1998; 2 refs.

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Book
Literature Type
Conference
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AbstractAbstract
[en] A method of operating a nuclear reactor having a core and coolant displacer elements arranged in the core wherein is established a reactor coolant temperature set point at which it is desired to operate said reactor and first reactor coolant teperature band limits are provided within which said set point is located and it is desired to operate said reactor characterized in that said reactor coolant displacer are moved relative to the reactor core for adjusting the volume of reactor coolant in said core as said reactor coolant temperature approaches said first band limits thereby to maintain said reactor coolant temperature near said set point and within said first band limits
Primary Subject
Source
3 Dec 1981; 34 p; ZA PATENT DOCUMENT 82/8401/A/; Available from Patents Office, Private Bag X400, Pretoria, 0001; Priority 16 December 1980 United States. No. 217,054.
Record Type
Patent
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Bourhim, A., E-mail: bourhim@ictp.trieste.it
Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)2002
Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)2002
AbstractAbstract
[en] In this paper, we study the local spectral properties for both unilateral and bilateral weighted shift operators. (author)
Primary Subject
Source
Sep 2002; 22 p; Also available at: http://www.ictp.trieste.it; 13 refs
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Report
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AbstractAbstract
[en] This patent describes a nuclear reactor system having a nuclear reactor which has a core including fuel assemblies, means for transmitting through the core a coolant, the coolant having a predetermined neutron-energy moderating property, sealed tubes in the core, each tube containing a material having a different neutron-energy moderating property than the coolant, means, when actuated, to engage at least certain of the tubes, for opening certain of the tubes to permit the coolant to replace the material in the tubes thereby to change the energy spectrum of the neutrons in the reactor, hydraulic means, connected to the opening means, for actuating the opening means to engage certain of the tubes to open the tubes. A device, external to the reactor, connected to the hydraulic means controlls the actuation of the opening means, the opening means being so set with reference to the tubes that only certain of the tubes are opened at any time as the opening means is advanced towards the tubes by the hydraulic means
Primary Subject
Secondary Subject
Source
11 Mar 1986; vp; US PATENT DOCUMENT 4,575,448/A/; U.S. Commissioner of Patents, Washington, D.C. 20231, USA, $.50
Record Type
Patent
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] A method of operating a nuclear reactor having a core and coolant displacer elements arranged in the core wherein is established a reator coolant temperature set point at which it is desired to operate said reactor and first reactor coolant temperature band limits are provided within which said set point is located and it is desired to operate said reactor charactrized in that said reactor coolant displacer elements are moved relative to the reactor core for adjusting the volume of reactor coolant in said core as said reactor coolant temperature approaches said first band limits thereby to maintain said reactor coolant temperature near said set point and within said first band limits
Primary Subject
Source
3 Dec 1981; 34 p; ZA PATENT DOCUMENT 81/8401/A/; Available from Patents Office, Private Bag X400, Pretoria, 0001; Priority 16 Dec 1980 United States. No. 217,054.
Record Type
Patent
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INIS VolumeINIS Volume
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AbstractAbstract
[en] We consider a duplicated two-level system where each two-level subsystem is driven by a strong resonant femtosecond pulse and a weak resonant femtosecond pulse connects cross transitions. Strong interference effects are induced in such a configuration leading to a modulation of the medium gain as a function of the relative phase φ between the pulses [J. C. Delagnes and M. A. Bouchene, Phys. Rev. Lett. 98, 053602 (2007)]. We study here the influence of the temporal overlap between the pulses on the dynamics of the system and the medium gain. We show that the dynamics is dominated by two competing phenomena: Light shifts (LS) induced by the driving pulse that prevails for small delays and free induction decay (FID) that prevails for large delays. LS enhance the medium gain for φ=π/2 and reduce it for φ=0, whereas FID always leads to a decrease of the medium gain
Primary Subject
Source
(c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
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Journal Article
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