Assessment of spectral history influence on PWR and WWER core
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Y. Bilodid
Abstract
The few-group cross section libraries, used by reactor dynamics codes, are affected by the spectral history effect – a dependence of fuel cross sections not only on burnup, but also on local spectral conditions during burnup. Neglecting this effect leads to an additional component of error in neutron-physical characteristics. Two solution approaches to this problem implemented in the reactor dynamic code DYN3D are described and compared in this paper: a cross section correction method based on239Pu concentration and separate cross sections treatment for each axial layer of reactor core. Steady-state and burnup characteristics of a PWR and a WWER-1000 cores, calculated by DYN3D with and without cross section corrections, are compared. An impact of the correction on transient calculations is studied for a control rod ejection example. Studies have shown a significant influence of spectral history on axial power and burnup distributions as well as on calculated cycle length. Two different correction methods have shown similar major effects.
Kurzfassung
Die Wenig-Gruppen-Bibliotheken von Wirkungsquerschnitten, wie sie in Kernsimulatoren benutzt werden, werden durch sogenannte History-Effekte beeinflusst. Das bedeutet, dass die Wirkungsquerschnittsdaten nicht nur vom Brennstoffabbrand abhängen, sondern auch vom lokalen Neutronenflussspektrum, das während der Abbrandgeschichte vorherrscht. Die Vernachlässigung dieser Effekte führt zu einer zusätzlichen Fehlerkomponente in den berechneten neutronenphysikalischen Parametern. Im vorliegenden Artikel werden zwei verschiedene Methoden beschrieben, wie History-Effekte im Reaktordynamikprogramm DYN3D behandelt werden können: zum einen durch die Ein-führung von Wirkungsquerschnitts-Korrekturen in Abhängigkeit von der Konzentration des Nuklids Pu-239, zum anderen durch eine gesonderte Berechnung der Wirkungsquerschnitte individuell für jeden Höhenabschnitt des Kerns. Es wurden stationäre Zustände und Abbrandparameter für den Kern eines DWR und eines WWER-1000 verglichen, die mit Hilfe von DYN3D mit und ohne Wirkungsquerschnitts-Korrektur berechnet wurden. Der Einfluss von History-Korrekturen auf das transiente Kernverhalten wurde anhand eines Regelstabauswurfs untersucht. Die Untersuchungen haben gezeigt, dass die Spektralgeschichte einen wesentlichen Einfluss auf das axiale Leistungsprofil, die Abbrandverteilung sowie auf die berechnete Zykluslänge hat. Die beiden verschiedenen Methoden für die History-Korrekturen bewirken vergleichbare Effekte.
References
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© 2012, Carl Hanser Verlag, München
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries/Kurzfassungen
- Editorial
- Research on the reactor physics and reactor safety of VVER reactors – Selected contributions to the XXIst Symposium of the Atomic Energy Research organization
- Technical Contributions/Fachbeiträge
- Development of multi-group spectral code TVS-M
- Qualification of the APOLLO2 lattice physics code of the NURISP platform for VVER hexagonal lattices
- The simplified P3 approach on a trigonal geometry of the nodal reactor code DYN3D
- An analytical solution for the consideration of the effect of adjacent fuel assemblies; extension to VVER-440 type fuel assemblies
- Studies on boiling water reactor design with reduced moderation and analysis of reactivity accidents using the code DYN3D-MG
- Simulations of RUTA-70 reactor with CERMET fuel using DYN3D/ATHLET and DYN3D/RELAP5 coupled codes
- Analysis of coolant flow in central tube of VVER-440 fuel assemblies
- Effect of spacer grid mixing vanes on coolant outlet temperature distribution
- Study on severe accidents and countermeasures for VVER-1000 reactors using the integral code ASTEC
- Assessment of spectral history influence on PWR and WWER core
- New practice for the evaluation of rod efficiency measurement by rod drop at the NPP Paks
- Comparison of square and hexagonal fuel lattices for high conversion PWRs
- VVER-440 with inert matrix fuel – viable direction to sustainability
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries/Kurzfassungen
- Editorial
- Research on the reactor physics and reactor safety of VVER reactors – Selected contributions to the XXIst Symposium of the Atomic Energy Research organization
- Technical Contributions/Fachbeiträge
- Development of multi-group spectral code TVS-M
- Qualification of the APOLLO2 lattice physics code of the NURISP platform for VVER hexagonal lattices
- The simplified P3 approach on a trigonal geometry of the nodal reactor code DYN3D
- An analytical solution for the consideration of the effect of adjacent fuel assemblies; extension to VVER-440 type fuel assemblies
- Studies on boiling water reactor design with reduced moderation and analysis of reactivity accidents using the code DYN3D-MG
- Simulations of RUTA-70 reactor with CERMET fuel using DYN3D/ATHLET and DYN3D/RELAP5 coupled codes
- Analysis of coolant flow in central tube of VVER-440 fuel assemblies
- Effect of spacer grid mixing vanes on coolant outlet temperature distribution
- Study on severe accidents and countermeasures for VVER-1000 reactors using the integral code ASTEC
- Assessment of spectral history influence on PWR and WWER core
- New practice for the evaluation of rod efficiency measurement by rod drop at the NPP Paks
- Comparison of square and hexagonal fuel lattices for high conversion PWRs
- VVER-440 with inert matrix fuel – viable direction to sustainability
