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Prediction of the onset of flow instability in the ETRR-2 research reactor under loss of flow accident

  • H. A. Khater , S. El-Din El-Morshdy and M. M. A. Ibrahim
Published/Copyright: April 6, 2013
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Kerntechnik
From the journal Kerntechnik Volume 72 Issue 1-2

Abstract

In the present work, prediction of the onset of flow instability (OFI) in Egypt's second Research Reactor (ETRR-2) under loss of flow accident (LOFA) conditions due to loss of off-site power has been performed based on the model developed in previous work. Calculations are performed for LOFA with Scram due to low flow signal at 90% of the nominal flow where the time length that covers this transient is 4.8 seconds. Both, the best-estimate and conservative calculations are performed under the specified operating conditions and geometrical data of ETRR-2 for both, exponential and ramp pressure gradient change. The OFI locus is predicted and plotted against the flow velocity, exit coolant temperature and bubble detachment parameter for several heat fluxes. The results are analyzed and assessed in order to obtain the safety margins for OFI phenomenon that measure how far the operating conditions are from the OFI locus. It is found that, the safety margins for OFI phenomenon in the best-estimate calculation are 2.62 and 2.35 for steady state and LOFA transient respectively, while its values in the conservative calculation are 1.68 and 1.47, respectively.

Kurzfassung

In der vorliegenden Arbeit wird die Prognostizierung der Entstehung von Strömungsinstabilitäten (OFI) im zweiten Ägyptischen Forschungsreaktor (ETTR-2) bei einem Strömungsverlust-Störfall (LOFA) aufgrund des Versagens der externen Stromversorgung behandelt, die auf dem in früheren Untersuchungen entwickelten Modells basiert. Die Berechnungen wurden für LOFA-Störfall mit Schnellabschaltung beim Ansprechen des Signals „Durchsatz zu niedrig“ bei 90% der Nominaldurchsatzmenge durchgeführt, wobei die Zeiterfassungsdauer dieser Transiente 4.8 sec beträgt. Sowohl die Best-Estimate- als auch die konservativen Rechnungen wurden unter Berücksichtigung spezifischer Betriebsbedingungen und geometrischer Daten der ETTR-2-Anlage für expotentielle und rampenförmige Druckgradientenverläufe durchgeführt. Der Instabilitätspunkt für OFI wurde vorhergesagt und in Abhängigkeit von der Strömungsgeschwindigkeit, Ausgangskühltemperatur und Parameter der Blasenfreisetzung für verschiedene Wärmeströme aufgezeichnet. Die Ergebnisse wurden analysiert und abgeschätzt, um die Sicherheitsbereiche für OFI-Phänome zu erhalten und den Abstand von Betriebsparametern bis zu dem OFI-Punkt zu messen. Bei Best-Estimate-Rechnungen betragen die Sicherheitsbereiche in Bezug auf OFI-Phänome für stationäre Strömung 2,62 und für LOFA-Transienten 2,35 und bei konservativen Berechnungen entsprechend 1,68 und 1,47.

References

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Received: 2006-12-25
Published Online: 2013-04-06
Published in Print: 2007-03-01

© 2007, Carl Hanser Verlag, München

Articles in the same Issue

  1. Contents/Inhalt
  2. Contents
  3. Summaries/Kurzfassungen
  4. Summaries
  5. Technical Contributions/Fachbeiträge
  6. Wavelet techniques for the determination of the decay ratio in boiling water reactors
  7. Analytical and experimental investigations of shear stress in rod bundles with irregular cells
  8. Incineration of weapon grade plutoniumin a (DT) fusion driven hybrid reactor using various coolants
  9. Calculation of the pin power distribution for a thorium reactor assembly and benchmarking
  10. Comparative assessment of methods for the reactivity measurement in subcritical systems by pulsed experiments
  11. Thermal-hydraulic modeling of reactivity accidents in MTR reactors
  12. Prediction of the onset of flow instability in the ETRR-2 research reactor under loss of flow accident
  13. Time-dependent albedo problem for quadratic anisotropic scattering
  14. HN solutions of the time dependent linear neutron transport equation for a slab and a sphere
  15. Application of the UN method to the reflected critical slab problem for one-speed neutrons with forward and backward scattering
  16. The effects of different expansions of the exit distribution on the extrapolation length for linearly anisotropic scattering
  17. Technical Note
  18. Shadowing the earth from Lagrange Point L1
https://doi.org/10.3139/124.100318

Articles in the same Issue

  1. Contents/Inhalt
  2. Contents
  3. Summaries/Kurzfassungen
  4. Summaries
  5. Technical Contributions/Fachbeiträge
  6. Wavelet techniques for the determination of the decay ratio in boiling water reactors
  7. Analytical and experimental investigations of shear stress in rod bundles with irregular cells
  8. Incineration of weapon grade plutoniumin a (DT) fusion driven hybrid reactor using various coolants
  9. Calculation of the pin power distribution for a thorium reactor assembly and benchmarking
  10. Comparative assessment of methods for the reactivity measurement in subcritical systems by pulsed experiments
  11. Thermal-hydraulic modeling of reactivity accidents in MTR reactors
  12. Prediction of the onset of flow instability in the ETRR-2 research reactor under loss of flow accident
  13. Time-dependent albedo problem for quadratic anisotropic scattering
  14. HN solutions of the time dependent linear neutron transport equation for a slab and a sphere
  15. Application of the UN method to the reflected critical slab problem for one-speed neutrons with forward and backward scattering
  16. The effects of different expansions of the exit distribution on the extrapolation length for linearly anisotropic scattering
  17. Technical Note
  18. Shadowing the earth from Lagrange Point L1
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