Filters
Results 1 - 10 of 19579
Results 1 - 10 of 19579.
Search took: 0.042 seconds
Sort by: date | relevance |
AbstractAbstract
[en] In its fourth phase, a hypothetic core melt interacts with the concrete of the reactor foundation. This phase may last several days. Experimental laboratory investigations and theoretical models on the basis of model experiments aim at determining the time curve of the temperature of the core melt in order to quantify the processes up to the solidification of the melt and the end of concrete destroyal. Material interactions: 1) The two phases of the core melt, oxidic and metallic, remain separate for a long period of time. In dependence of the degree of oxidation of the system, the elemental distribution and, in particular, the fission products in the melt may be assessed. 2) The changes in the material values of the core melt in dependence of the temperature curve may be qualitatively assessed. 3) The solidification temperature of the oxidic phase of the core melt may be given in dependence of (UO2 + ZrO2) content. Thermal interactions: 1) The ratio vertical/radial erosion, which determines the cavity shape, is described in the correct order of magnitude by the extended film model. 2) The correct order of magnitude of the erosion rates is described by the concrete destruction model coupled with the film model. 3) The effects of the different concrete destruction enthalpies and concrete compositions (amount of gaseous decomposition products) may be estimated by the model calculations. (orig./HP)
[de]
In der vierten Phase einer hypothetischen Kernschmelze tritt diese in Wechselwirkung mit dem Beton des Reaktorfundaments. Diese Phase kann sich ueber lange Zeitraeume in der Groessenordnung von Tagen erstrecken. Ziel experimenteller Untersuchungen im Labormassstab und, auf der Basis von Modellversuchen, theoretischer Modelle ist es, den zeitlichen Verlauf der Temperatur in der Kernschmelze zu bestimmen, um die Vorgaenge bis zur Erstarrung der Schmelze und der Beendigung der Betonzerstoerung zu quantifizieren. Stoffliche Wechselwirkungen: 1) Die beiden Phasen der Kernschmelze, die oxidische und die metallische Schmelze, liegen ueber lange Zeitraeume getrennt vor. In Abhaengigkeit vom Oxidationsgrad des Systems koennen Aussagen ueber die Verteilung der Elemente und insbesondere der Spaltprodukte in der Schmelze getroffen werden. 2) Die Aenderungen der Stoffwerte der Kernschmelze in Abhaengigkeit vom Temperaturverlauf koennen qualitativ abgeschaetzt werden. 3) Die Erstarrungstemperatur der oxidischen Phase der Kernschmelze kann in Abhaengigkeit vom (UO2 + ZrO2)-Gehalt angegeben werden. Thermische Wechselwirkungen: 1) Das Verhaeltnis von vertikaler zu radialer Erosion, das die Kavernenform bestimmt, wird durch das erweiterte Filmmodell in der richtigen Groessenordnung beschrieben. 2) Die richtige Groessenordnung der Erosionsgeschwindigkeiten wird durch das mit dem Filmmodell gekoppelte Betonzerstoerungsmodell wiedergegeben. 3) Die Auswirkungen der verschiedenen Betonzerstoerungsenthalpien und der verschiedenen Zusammensetzungen der Betone (Anteil an gasfoermigen Zersetzungsprodukten) koennen durch die Modellrechnungen abgeschaetzt werden. (orig./HP)Original Title
Zur Wechselwirkung einer Kernschmelze mit Beton
Primary Subject
Source
1977; 24 p; Annual Colloquium of the Projekt Nukleare Sicherheit of the Gesellschaft fuer Kernforschung; Karlsruhe, Germany, F.R; 1 Dec 1977; 12 figs.; 6 refs.
Record Type
Miscellaneous
Literature Type
Conference
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] This paper gives briefly the characteristics of the RBMK reactors and describes the possible history of the accident of the reactor Tchernobyl-4
[fr]
Cet article donne assez rapidement les caracteristiques des reacteurs RBMK et decrit le scenario possible de l'accident du reacteur Tchernobyl no.4Original Title
Les caracteristiques des reacteurs RBMK et le deroulement possible de l'accident
Primary Subject
Secondary Subject
Record Type
Journal Article
Journal
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Johnson, J.E.
Westinghouse Electric Corp., Pittsburgh, Pa. (USA)1976
Westinghouse Electric Corp., Pittsburgh, Pa. (USA)1976
AbstractAbstract
[en] In order to protect a nuclear reactor efficiently also when the fuel elements begin to melt, it is proposed instead of the core catcher provided for this case, to arrange a larger number of smaller collecting vessels, each below a fuel element, intended to catch melted particles, to cool them well, and if necessary, to discharge them. The containers are made of high-temperature resistant material (stainless steel, ceramics). 9 drawings illustrate the invention. (UWI)
[de]
Um einen Kernreaktor auch in dem Fall gut zu schuetzen, wenn Brennelemente zu schmelzen beginnen, wird vorgeschlagen, anstelle eines fuer diesen Fall vorgesehenen Auffangbehaelters unterhalb des Reaktorkerns eine groessere Zahl kleinerer Auffangbehaelter jeweils unter einem Brennelement anzuordnen, die dazu bestimmt sind, geschmolzene Teilchen aufzufangen, gut zu Kuehlen und gegebenenfalls abzuleiten. Die Behaelter sind aus hochtemperaturbestaendigem Werkstoff (rostfreiem Stahl, Keramik) hergestellt. 9 Zeichnungen erlaeutern die Erfindung. (UWI)Original Title
Kernreaktor
Primary Subject
Source
8 Jul 1976; 29 p; DE PATENT DOCUMENT 2557332/A/; Also available from Dt. Patentamt, Muenchen (FRG); 9 figs.
Record Type
Patent
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Horvat, M.; Leskovar, M.; Marn, J.
Third Regional Meeting: Nuclear Energy in Central Europe, Proceedings1996
Third Regional Meeting: Nuclear Energy in Central Europe, Proceedings1996
AbstractAbstract
[en] Melting ultimately requires the heat production rate to exceed the removal rate. In a nuclear reactor this situation is initiated by either overpower or undercooling conditions. The latter is related to reduced cooling through loss of coolant flow or loss of coolant itself and may lead to general meltdown of the reactor core. Molten material is accumulated in the lower plenum of the reactor pressure vessel. The separation of phases results from different components densities of molten material. High temperature molten UO2 will slowly melt through the wall of RPV lower plenum. To avoid disruption of RPV, an instantaneous heat transfer is needed. To simulate the situation described above, general multiphase flow equations were developed. In order to describe the multiphase flow fully, the continuity, momentum and energy equations were derived using ensemble averaging rather then time or spatial averaging. Because of geometry of the lower plenum a spherical coordinate system was used, to enhance the accuracy of the calculation on the border. (author)
Primary Subject
Source
Stritar, A.; Jencic, I. (Nuclear Society of Slovenia (Slovenia)) (eds.); European Nuclear Society (Switzerland); Ministry of Science and Technology of Slovenia, Ljubljana (Slovenia); Nuclear Power Plant Krsko (Slovenia); 562 p; ISBN 961-6207-04-0;
; 1996; p. 237-244; 3. Regional Meeting: Nuclear Energy in Central Europe; Portoroz (Slovenia); 16-19 Sep 1996; Available from Nuclear Society of Slovenia, Jozef Stefan Institute, Jamova 39, Ljubljana (SI); 9 refs., 3 figs.

Record Type
Miscellaneous
Literature Type
Conference
Report Number
Country of publication
Reference NumberReference Number
Related RecordRelated Record
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] The severe core meltdown accident, which is not included as a design basis accident, has high consequence and low probability of occurrence and turns out to be a major risk factor in the overall risk assessment. The physical mechanisms of containment failure in core meltdown accidents are identified as steam explosion, debris bed coolability, hydrogen burning, steam spike and core-concrete interaction. The state of technology review is made for each subtopic about the previous and current researches for better understanding of the phenomenon. (Author)
Primary Subject
Record Type
Journal Article
Journal
Journal of the Korean Nuclear Society; ISSN 0372-7327;
; v. 17(1); p. 53-67

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] The TMI-2 accident has initiated a new phase of safety research. It is necessary to consider severe accidents with degraded or molten core. For NRC there was a need for an improved understanding of this reactor behaviour and the 'Severe Fuel Dage Program' was initiated. Planned are in-pile experiments in PBF, NRU and ESSOR and in addition separate effects tests and results from TMI-2. The analytical component of the program is the development of different versions of the code SCDAP for the detailed analysis during severe accident transients. (Author)
[de]
Der Stoerfall TMI-2 hat eine neue Phase der Reaktorsicherheitsforschung eingeleitet. Ernstere Unfaelle, wie das Freilegen und Schmelzen des Cores muessen betrachtet werden. Dazu wurde von der NRC das 'Severe Fuel Damage Program' ins Leben gerufen. Geplant sind In-Pile-Experimente bei PBF, NRU und ESSOR, dazu Separate-Effects-Tests und Auswertungen bei TMI-2. Parallel dazu werden Modelle fuer die verschiedenen Versionen des Codes SCDAP entwickelt, der zur Analyse solcher Stoerfaelle dienen soll. (Autor)Original Title
Das amerikanische 'Severe Fuel Damage Program'
Primary Subject
Source
Mar 1982; 62 p; RS--200/82
Record Type
Report
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
No abstract available
Original Title
Rechnerische Behandlung des Schmelzens bei Reaktor-Stoerfaellen mit Kernschmelzen
Primary Subject
Source
Deutsches Atomforum e.V., Bonn (Germany, F.R.); Kerntechnische Gesellschaft im Deutschen Atomforum e.V., Bonn (Germany, F.R.); p. 335-338; 1980; p. 335-338; Fachinformationszentrum Energie, Physik, Mathematik; Eggenstein-Leopoldshafen, Germany, F.R; Annual meeting on nuclear technology (Reactor conference '80); Berlin, Germany, F.R; 25 - 27 Mar 1980; Short communication only.
Record Type
Book
Literature Type
Conference
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
No abstract available
Original Title
LMFBR
Primary Subject
Secondary Subject
Source
American Nuclear Society 1975 winter meeting; San Francisco, CA, USA; 16 Nov 1975; Published in Summary Form Only.
Record Type
Journal Article
Literature Type
Conference
Journal
Transactions of the American Nuclear Society; v. 22 p. 372-373
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Steinwarz, W.; Dyllong, N.; Fischer, M.; Hurtado, A.M.
Annual meeting on nuclear technology '97. Proceedings1997
Annual meeting on nuclear technology '97. Proceedings1997
AbstractAbstract
[en] Short communication
Original Title
Repraesentative Versuche zum Ausbreitungsverhalten von Kernschmelzen
Primary Subject
Secondary Subject
Source
Deutsches Atomforum e.V., Bonn (Germany); Kerntechnische Gesellschaft e.V., Bonn (Germany); 700 p; ISSN 0720-9207;
; May 1997; p. 236-239; Inforum Verl; Bonn (Germany); Annual meeting on nuclear technology and membership meeting of Deutsches Atomforum e.V; Jahrestagung Kerntechnik (JK '97) und Mitgliederversammlung des Deutschen Atomforums e.V; Aachen (Germany); 13-15 May 1997

Record Type
Book
Literature Type
Conference
Country of publication
Reference NumberReference Number
Related RecordRelated Record
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] A survey is given of the development of probabilistic risk analyses from 1957 till now. Some of these risk studies, which have been performed in the past years, are discussed with emphasis on the risks, found in these studies, on nuclear melt-down and on the relative contribution of the most important initiating events. Only the contribution of internal events are taken into account. Finally some factors are indicated which could diminish the risk of a melt-down accident. (Auth.)
Original Title
De kans op het optreden van kernsmeltingsongevallen
Primary Subject
Secondary Subject
Source
Loon, A.J. van (ed.); Koninklijk Inst. voor Ingenieurs, Arnhem (Netherlands). Afdeling voor Kerntechniek; 195 p; ISBN 90-353-1001-2;
; 1987; p. 157-167; KIVI-Kerntechniek; Arnhem (Netherlands); How can the engineer minimize the risks of nuclear power plants?; The Hague (Netherlands); 20 Jan 1987; 8 refs.; 3 figs.; 1 table.

Record Type
Book
Literature Type
Conference
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
1 | 2 | 3 | Next |