Sensitivity analysis of the Peach Bottom Turbine Trip 2 experiment
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A. Bousbia-Salah
Abstract
The recent availability of powerful computer and computational techniques has enlarged the possibilities to perform best estimate simulations of complex scenarios in nuclear power plants. Nowadays, the coupled codes method, which consists in incorporating three-dimensional (3D) neutron modeling of the reactor core into system codes, is extensively used. It is particularly suited for simulating transients that involve core spatial asymmetric phenomena and strong feedback effects between core neutronics and reactor loop thermal-hydraulics. Within this framework the Peach Bottom BWR 2 Turbine Trip test was selected since it involves a rapid pressure induced positive reactivity addition into the core. It is also characterized by a self-limiting power course due to compensated inherent reactivity mechanisms. To perform a numerical simulation of the turbine trip a reference case was run for the coupled thermal-hydraulic system code RELAP5/mod3.3 and 3D neutron kinetic PARCS/2.3 code. The overall data comparison shows good agreements between the calculations and most of the significant global aspects observed experimentally. However, the test is very sensitive to the feedback modeling and requires a tightly accurate simulation of the thermal-hydraulic and the cross sections parameters. For this purpose, sensitivity studies have been carried out in order to identify the most influential parameters that govern the transient behavior. The considered cases showed that the self-limiting power amplitude as predicted by the coupled code calculation is mainly due to delayed feedback mechanisms whereas the experimental data shows that the power quenching before the Scram is governed by prompt feedback effects.
Kurzfassung
Die heute zur Verfügung stehenden sehr leistungsfähigen Computer und Rechenverfahren haben die Möglichkeiten Simulationen komplexer Szenarien in Kernkraftwerken durchzuführen stark erweitert. Heutzutage werden die gekoppelten Codes, die die dreidimensionale (3D) Neutronenmodellierung des Reaktorkerns in die Systemcodes integrieren, in großem Umfang genutzt. Sie sind insbesondere geeignet zur Simulation von Transienten, die zu räumlich asymmetrischen Phänomenen im Kern führen und eine starke Kopplung zwischen der Leistungserzeugung im Kern und der Thermohydraulik im Kühlkreislauf bewirken. In diesem Zusammenhang wurde der Peach Bottom Turbine Trip 2 Test gewählt, da dieser zu einer durch den schnellen Druckanstieg bewirkten positiven Reaktivitätszufuhr führt. Die Transiente ist auch charakterisiert durch einen selbstbegrenzenden Leistungsverlauf infolge inhärenter Reaktivitätsmechanismen. Zur numerischen Simulation der Turbinenschnellabschaltung wurde ein Referenzfall mit dem gekoppelten thermohydraulischen Systemcode RELAP5/mod3.3 und dem 3D Neutronenkinetikcode PARCS/2.3 berechnet. Der Vergleich der Ergebnisse zeigt insgesamt eine gute Übereinstimmung zwischen den Berechnungen und den wesentlichen integralen experimentellen Ergebnissen. Es zeigte sich jedoch, dass der Test sehr empfindlich gegenüber der Modellierung der Rückkopplung ist und eine sehr genaue Simulation der thermohydraulischen Parameter und der Wirkungsquerschnitte erfordert. Es wurden deshalb Sensitivitätsanalysen durchgeführt, um so die Parameter zu identifizieren, die das Transientenverhalten am stärksten beeinflussen. Die betrachteten Fälle zeigen, dass die selbstbegrenzende Leistungsamplitude hauptsächlich von verzögerten Rückkopplungsmechanismen abhängt, während aus den Experimenten folgt, dass die Leistungsumkehr vor der Schnellabschaltung von prompten Rückkopplungseffekten abhängt.
References
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© 2004, Carl Hanser Verlag, München
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Technical Contributions/Fachbeiträge
- Sensitivity analysis of the Peach Bottom Turbine Trip 2 experiment
- Theoretical and experimental investigations into natural circulation behaviour in a simulated facility of the Indian PHWR under reduced inventory conditions
- A new data-condensation method based on multidimensional minimisation
- Current international activities to increase fire protection knowledge for nuclear power plants
- Simple formulas for conservatively calculating the fuel rod cladding strains due to RIA
- Accelerator driven systems for transmutation and energy production: challenges and dangers
- A method for in-situ quantification of oxygen in oil using fast neutron activation analysis
- The time-dependent effect of the biological component of 137Cs soil contamination
- Letter to the Editor
- Remarks on pulsed neutron activation
- On the critical radius of reflected spheres
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Technical Contributions/Fachbeiträge
- Sensitivity analysis of the Peach Bottom Turbine Trip 2 experiment
- Theoretical and experimental investigations into natural circulation behaviour in a simulated facility of the Indian PHWR under reduced inventory conditions
- A new data-condensation method based on multidimensional minimisation
- Current international activities to increase fire protection knowledge for nuclear power plants
- Simple formulas for conservatively calculating the fuel rod cladding strains due to RIA
- Accelerator driven systems for transmutation and energy production: challenges and dangers
- A method for in-situ quantification of oxygen in oil using fast neutron activation analysis
- The time-dependent effect of the biological component of 137Cs soil contamination
- Letter to the Editor
- Remarks on pulsed neutron activation
- On the critical radius of reflected spheres
