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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
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Manson, M.
CEA, 75-Paris (France)1986
CEA, 75-Paris (France)1986
AbstractAbstract
[en] The present invention proposes a spectral-shift rod designed to be introduced in a classical guide tube able besides to receive an absorber rod, without the spectral-shift rod being subject, to important shocks or vibrations. Most time, the spectral-shift rod is a fertile rod comprising a stack of fertile pellets
[fr]
La presente invention a pour objet un crayon de variation de spectre de conception particuliere pouvant etre introduit dans un tube guide de conception classique apte a recevoir par ailleurs un crayon absorbant, sans que ce crayon de variation de spectre ne soit soumis a des chocs ou a des vibrations importantesOriginal Title
Reacteur nucleaire a variation de spectre et a eau sous pression
Primary Subject
Secondary Subject
Source
12 Dec 1986; 5 Jun 1985; 26 p; FR PATENT DOCUMENT 2583204/A/; FR PATENT APPLICATION 8508479; Available from Institut National de la Propriete Industrielle, Paris (France); Application date: 5 Jun 1985
Record Type
Patent
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Leclecq, J.; Canat, J.N.
Fragema, 69 - Lyon (France)1985
Fragema, 69 - Lyon (France)1985
AbstractAbstract
[en] The present cap is for a PWR fuel assembly. The fuel assembly has a lower cap integral with the upper cap by means of guide tubes receiving the control rod assemblies. The cap has a support for a cluster of control rods. Sliding spacers allow the support to slide in a direction parallel to the guide tubes one. A spring or several springs are integrated to the cap and arranged between the upper cap and the support to slowdown the control assembly at the end of their drop. One sliding spacer at least comprises stop motion devices fixing the rest position of the support plate. The invention finds an application in variable spectrum reactors
[fr]
L'embout est destine a un assemblage de combustible nucleaire pour reacteur a eau sous pression, assemblage comprenant un embout inferieur solidarise d'une piece de structure appartenant a l'embout superieur par des tubes guides de reception d'une grappe de crayons de commande. L'embout comporte une piece d'appui de la grappe en fin de chute de celle-ci. Des entretoises coulissantes permettent a la piece d'appui de coulisser parallelement a la direction des tubes guides. Un ressort ou plusieurs sont integres a l'embout et disposes entre la piece de structure et la piece d'appui afin de freiner la grappe en fin de chute de cette derniere. L'une au moins des entretoises coulissantes comporte des moyens de butee fixant la position de repos de la plaque d'appui. L'invention trouve une application particulierement importante, bien que non exclusive, dans les reacteurs dits a variation ou a glissement de spectreOriginal Title
Embout superieur pour assemblage de combustible nucleaire
Primary Subject
Source
11 Oct 1985; 10 Apr 1984; 14 p; FR PATENT DOCUMENT 2562708/A/; FR PATENT APPLICATION 8405652; Available from Institut National de la Propriete Industrielle, Paris (France); Application date: 10 Apr 1984
Record Type
Patent
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INIS IssueINIS Issue
AbstractAbstract
No abstract available
Primary Subject
Secondary Subject
Source
Israel Nuclear Society, Yavne; Israel Health Physics Society; Radiation Research Society of Israel; Israel Society of Medical Physics; Transactions; v. 12; 206 p; 1985; p. 25-28; Nuclear Societies of Israel annual meeting; Beer-Sheva (Israel); 6-7 Feb 1985; Published in summary form only.
Record Type
Miscellaneous
Literature Type
Conference
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AbstractAbstract
[en] France is considering plutonium recycling in existing PWR's. Development of FRAMATOME's spectral shift reactor is described and preliminary results of core studies are communicated
Primary Subject
Record Type
Journal Article
Journal
Nuclear Europe; CODEN NUEUD; v. 6(4); p. 23-27
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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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Millot, J.P.
Societe Franco-Americaine de Constructions Atomiques (FRAMATOME), 92 - Courbevoie (France)1985
Societe Franco-Americaine de Constructions Atomiques (FRAMATOME), 92 - Courbevoie (France)1985
AbstractAbstract
[en] This paper presents Framatome studies concerning the optimization of water power reactors. Three fuel models have been taken into account: fuel with grid and stainless steel cladding; fuel with grid and zircaloy cladding; and, fuel with grid, zircaloy cladding and spectral shift
Primary Subject
Source
1985; 10 p; Workshop on advanced light and heavy water reactor technology; Vienna (Austria); 26-30 Nov 1984
Record Type
Report
Literature Type
Conference
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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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AbstractAbstract
[en] The aim of the present invention is to propose a flexible pressurized water reactor to be controlled, its core comprising assemblies of same geometry and interchangeable to allow its operation at different conversion ratios
[fr]
Le but de la presente invention est donc de proposer un procede d'exploitation souple d'un reacteur nucleaire a eau sous pression dont le coeur est constitue d'assemblages combustibles de geometrie identique et interchangeables permettant son fonctionnement a des taux de conversion differentsOriginal Title
Procede d'exploitation d'un reacteur a eau legere et a variation de spectre
Primary Subject
Source
6 Dec 1985; 30 May 1984; 12 p; FR PATENT DOCUMENT 2565396/A/; FR PATENT APPLICATION 8408548; Available from Institut National de la Propriete Industrielle, Paris (France); Application date: 30 May 1984
Record Type
Patent
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Kashiwai, Shin-ichi; Yokomizo, Osamu; Orii, Akihito.
Hitachi Ltd., Tokyo (Japan)1992
Hitachi Ltd., Tokyo (Japan)1992
AbstractAbstract
[en] In a reactor core of a BWR type reactor, the area of a flow channel in a lower portion of a downcoming pipe for downwardly releasing steams present at the top portion in a water rod is increased. Further, a third coolant flow channel (an inner water rod) is disposed in an uprising having an exit opened near the inlet of the water rod and an inlet opened at the outside near the top portion of the water and having an increase flow channel area in the upper portion. The downcoming pipe in the water rod is filled with steams, and the void ratio is increased by so much as the flow channel area of the downcoming pipe is increased. Since the pressure difference between the inlet and the exit of the inner water rod is greater than the pressure difference between the inlet and the exit of the water rod, most of water flown into the inner water rod is discharged out of the exit in the form of water as it is. Since the area of the flow channel is increased in the portion of the inner water rod, void efficiency in the upper portion of the reactor core is decreased by so much. Since the void ratio is thus increased in the lower portion and the void efficiency is decreased in the upper portion of the reactor core, axial void distribution can be flattened. (N.H.)
Primary Subject
Source
25 Nov 1992; 15 May 1991; 5 p; JP PATENT DOCUMENT 4-337497/A/; JP PATENT APPLICATION 3-110145; Available from JAPIO. Also available from INPADOC; Application date: 15 May 1991
Record Type
Patent
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