Effect of spacer grid mixing vanes on coolant outlet temperature distribution
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T. Rämä
Abstract
In Loviisa VVER-440-type NPP the coolant outlet temperature of the hot subchannel is constantly monitored during the operation. According to the authority requirement the maximum subchannel outlet temperature must not exceed the saturation temperature. Coolant temperature distribution inside the fuel assembly is affected by the efficiency of the coolant mixing. In order to enhance the coolant mixing the fuel manufacturer is introducing the additional mixing vanes on the fuel bundle spacer grids. In the paper the effect of the different mixing vane modifications is studied with computational fluid dynamics (CFD) simulation. Goal of the modelling is to find vane modifications with which sufficient mixing is reached with acceptable increase in the spacer grid pressure loss. The results of the studies are discussed in the paper.
Kurzfassung
Im KKW Loviisa (WWER-440) wird die Austrittstemperatur des heiβesten Unterkanals des Kerns kontinuierlich während des Betriebs überwacht. Entsprechend den Vorgaben der Aufsichts- und Genehmigungsbehörde muss gewährleistet werden, dass diese Temperatur die Sättigungstemperatur nicht überschreitet. Die Temperaturverteilung des Kühlmittels innerhalb eines Brennelements wird durch die Effektivität der Vermischung des Kühlmittels beeinflusst. Um diese Durchmischung zu erhöhen haben die Brennelementhersteller zusätzliche Fahnen an den Abstandshaltern der Brennelemente angebracht. Im Beitrag wird der Einfluss verschiedener baulicher Ausführungen dieser Fahnen auf das Mischungsverhalten des Kühlmittels mit Hilfe von CFD-Berechnungen untersucht. Ziel dieser Modellierung ist es, eine Konstruktion zu finden, die zu einer besseren Vermischung mit gleichzeitig akzeptabler Erhöhung der Druckverluste an den Abstandshaltern führt. Die Ergebnisse werden im Beitrag diskutiert.
References
1 Brandt, T; Toppila, T.: Ways to enhance mixing inside WER-440 fuel rod bundle. Workshop on Nuclear Fuel Assembly Modelling and Experiments (NuFAME). Stockholm, Sweden. July 9–10, 2009Search in Google Scholar
2 Brandt, T,; Toppila, T.: CFD Study on mixing in WER-440 Fuel Rod Bundle With Guiding Vanes in Spacer Grids. Proceedings of the 17thInternational Conference on Nuclear Engineering (ICONE). Brus-sels, Belgium, July 12–16, 200910.1115/ICONE17-75316Search in Google Scholar
3 Brandt, T; Lahtinen, T: CFD Study on Coolant Mixing Inside WER-440 Fuel Rod Bundle. 19th AER symposium on WER reac-tor physics and reactor safety. Varna, Bulgaria, 20–25 September 2009Search in Google Scholar
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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
