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Analysis of the gas-diffusion process during a hypothetical air ingress accident in a modular high temperature gas cooled reactor

Abstract

A one-dimensional coupled diffusion-convection model has been established and it is shown, that experiments performed at JAERI have been recalculated successfully, thus validating the new model. Applying this model to the NACOK facility, now under construction at the Institute for Safety Research and Reactor Technology (ISR) of the KFA Juelich, a delay time until the onset of natural circulation was found to be 14 hours. For the 200 MW HTR-MODULE designed by the SIEMENS company about 39 hours are predicted. It was found that pressure disturbances, e.g. caused by environmental noise could significantly shorten the time delay until the onset of natural circulation. The onset time delay remains constant below 40 dB noise, reaches half of its value at 80 dB and tends to zero at 120 dB. Thus, the relevance of the delay effect with respect to safety related questions is reduced. (orig./HP) [Deutsch] Es wurde ein eindimensionales gekoppeltes Diffusions-Konvektions-Rechenmodell erstellt und zunaechst gezeigt, dass zur Validierung dieses Modells Experimente, welche am JAERI durchgefuehrt worden sind, mit gutem Erfolg nachgerechnet werden konnten. Die Anwendung des Modells auf das im ISR des KFA im Aufbau befindliche Experiment NACOK ergibt eine Verzoegerungszeit bis zum Einsatz der Naturkonvektion von 14 Stunden. Fuer  More>>
Publication Date:
Oct 01, 1993
Product Type:
Technical Report
Report Number:
Juel-2823
Reference Number:
SCA: 220900; 210300; PA: DEN-94:0F4396; EDB-94:062965; NTS-94:020565; SN: 94001185716
Resource Relation:
Other Information: PBD: Oct 1993
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; 21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; PEBBLE BED REACTORS; LOSS OF COOLANT; AIR FLOW; HTGR TYPE REACTORS; MODULAR STRUCTURES; PRIMARY COOLANT CIRCUITS; ONE-DIMENSIONAL CALCULATIONS; DIFFUSION; MATHEMATICAL MODELS; NATURAL CONVECTION; GRAPHITE; CORROSION; 220900; 210300; REACTOR SAFETY; POWER REACTORS, NONBREEDING, GRAPHITE MODERATED
OSTI ID:
10141532
Research Organizations:
Forschungszentrum Juelich GmbH (Germany). Inst. fuer Sicherheitsforschung und Reaktortechnik
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0944-2952; Other: ON: DE94758719; TRN: DE94F4396
Availability:
OSTI; NTIS (US Sales Only); INIS
Submitting Site:
DEN
Size:
40 p.
Announcement Date:
Jul 05, 2005

Citation Formats

Zhang, Z, Gerwin, H, and Scherer, W. Analysis of the gas-diffusion process during a hypothetical air ingress accident in a modular high temperature gas cooled reactor. Germany: N. p., 1993. Web.
Zhang, Z, Gerwin, H, & Scherer, W. Analysis of the gas-diffusion process during a hypothetical air ingress accident in a modular high temperature gas cooled reactor. Germany.
Zhang, Z, Gerwin, H, and Scherer, W. 1993. "Analysis of the gas-diffusion process during a hypothetical air ingress accident in a modular high temperature gas cooled reactor." Germany.
@misc{etde_10141532,
title = {Analysis of the gas-diffusion process during a hypothetical air ingress accident in a modular high temperature gas cooled reactor}
author = {Zhang, Z, Gerwin, H, and Scherer, W}
abstractNote = {A one-dimensional coupled diffusion-convection model has been established and it is shown, that experiments performed at JAERI have been recalculated successfully, thus validating the new model. Applying this model to the NACOK facility, now under construction at the Institute for Safety Research and Reactor Technology (ISR) of the KFA Juelich, a delay time until the onset of natural circulation was found to be 14 hours. For the 200 MW HTR-MODULE designed by the SIEMENS company about 39 hours are predicted. It was found that pressure disturbances, e.g. caused by environmental noise could significantly shorten the time delay until the onset of natural circulation. The onset time delay remains constant below 40 dB noise, reaches half of its value at 80 dB and tends to zero at 120 dB. Thus, the relevance of the delay effect with respect to safety related questions is reduced. (orig./HP) [Deutsch] Es wurde ein eindimensionales gekoppeltes Diffusions-Konvektions-Rechenmodell erstellt und zunaechst gezeigt, dass zur Validierung dieses Modells Experimente, welche am JAERI durchgefuehrt worden sind, mit gutem Erfolg nachgerechnet werden konnten. Die Anwendung des Modells auf das im ISR des KFA im Aufbau befindliche Experiment NACOK ergibt eine Verzoegerungszeit bis zum Einsatz der Naturkonvektion von 14 Stunden. Fuer den 200 MW HTR-MODUL der Firma SIEMENS werden etwa 39 Stunden vorhergesagt. Druckschwankungen, etwa hervorgerufen durch Umgebungslaerm, koennen diese Karenzzeit jedoch erheblich verkuerzen. Unterhalb von 40 dB Laerm bleibt die Verzoegerungszeit konstant, bei 80 dB halbiert sie sich und geht bei 120 dB gegen Null. Damit wird die sicherheitstechnische Nutzbarkeit dieses Verzoegerungseffektes eingeschraenkt. (orig./HP)}
place = {Germany}
year = {1993}
month = {Oct}
}