Abstract
Three dimensional computational-fluid-dynamics simulations are performed for the fluid flow within a 40 rod fuel bundle in a square arrangement with a central moderator channel. To ensure spacing between the rods, the design of the bundle uses thin wires wrapped counter-clockwise around each rod. This geometry is presently investigated in the framework of the European High-Performance Light-Water Reactor (HPLWR), which operates at supercritical pressure of 25 MPa. A section with one revolution located in the evaporator region of the HPLWR core is investigated using hydraulic (to ensure fully developed flow inlet boundary conditions and reference for heated cases) and thermal-hydraulic boundary conditions. The geometry of wrapped wires gives rise to additional mixing and a circulating or ‘sweeping’ flow near the outer and inner regions of the fuel element next to the wall of the so called fuel assembly and moderator box. Some interesting flow features associated with the complex three-dimensional flow with significant transverse velocity components are visualized as the first evaluated result of this diversified investigation.
Kurzfassung
Für ein Brennelement des European High-Performance Light-Water Reactors (HPLWR), der bei überkri-tischen Drücken von 25 MPa betrieben werden soll, wird eine Analyse der Kühlmittelströmung im Brennelement mit dem 3D-Computational Fluid Dynamics (CFD) Programm CFX-11 durchgeführt. Das Brennelement ist quadratisch aufgebaut und besteht aus einem zentralen Moderatorkanal und 40 Brennstäben. Die Abstandshalter bestehen aus dünnen Drähten, die gegen den Uhrzeigersinn um jeden Brennstab gewickelt sind. In den Berechnungen wird der Bereich einer Umwicklung des Abstandshalters in dem so genannten Verdampfer-Kernbereich im Detail untersucht unter Berücksichtigung hydraulischer und thermohydraulischer Randbedingungen. Diese sind so gewählt, dass als Randbedingung eine vollständig entwickelte Strömung im Eintritt vorliegt und dass diese als Referenz für die verschiedenen Randbedingungen bzgl. der Temperaturverteilungen dienen. Die Geometrie der gewickelten Drähte führt zu einer zusätzlichen Vermischung und ”Mitriss“-Strömung in der Nähe der äußeren und inneren Regionen des Brennelements, das sich in Wandnähe der Brennelementumwandung und Moderatorbox befindet. Einige interessante Strömungseigenschaften der komplexen 3D-Strömung mit signifikanten Queranteilen der Geschwindigkeit werden als erste Ergebnisse dieser Untersuchungen vorgestellt.
References
1 Fischer, K.; Schulenberg, T.; Laurien, E.: Design of a supercritical water-cooled reactor with a three-pass core arrangement. Nuclear Engineering and Design239 (2009) 800–812Search in Google Scholar
2 Schulenberg, T.; Starflinger, J.: Core Design Concepts for High Performance Light Water Reactors. Nuclear Engineering and Technology39 (2007) 249–256Search in Google Scholar
3 Schulenberg, T.et al.: European supercritical water cooled reactor. FISA, June 22–24, 2009, PragueSearch in Google Scholar
4 Li, H.; Wang, H.; Luo, Y.; Gu, H.; Shi, X.; Chen, T.; Laurien, E.; Zhu, Y.: Experimental investigation on heat transfer from a heated rod with a helically wrapped wire inside a square vertical channel to water at supercritical pressures. submitted to Nuclear Engineering and DesignSearch in Google Scholar
5 Himmel, S.; Class, A. G.; Laurien, E.; Schulenberg, T.: Determination of Mixing coefficients in a wire-wrapped HPLWR fuel assembly using CFD. In: Proc. of ICAPP-08, Anaheim, CA, USA, June 2008, paper 8053Search in Google Scholar
6 Monti, L.; Starflinger, J.; Schulenberg, T.: Effectiveness of an insulated fuel assembly to improve HPLWR core performance. 4th Int. Symp. on Supercritical Water-Cooled Reactors, March 8–11, 2009, Heidelberg, GermanySearch in Google Scholar
7 Gajapathy, R.; Velusamy, K.; Selvaraj, P.; Chellapandi, P.; Chetal, S. C.: CFD investigation of helical wire-wrapped 7-pin fuel bundle and the challenges in modelling full scale 217 pin bundle. Nuclear Engineering and Design237 (2007) 2332–2342 10.1016/j.nucengdes.2007.05.003Search in Google Scholar
8 Fischer, P.; Lottes, P.; Siegel, A.; Palmiotti, G.: Large Eddy Simulation of wire-wrapped fuel Pin-I: Hydrodynamics in a periodic array. Joint Int. topical Meeting on Mathematics & Computation and Supercomputing in Nuclear Applications (M&C+SNA 2007), Monterey, California, April 15–19 (2007)Search in Google Scholar
9 Bieder, U.; Ducros, F.; Fauchet, G.; Quemere, P.: CFD investigation of a full scale helical wire-wrapped 61-pin fuel bundle by using the code TRIO_U. Annual Meeting on Nuclear Technology, May 12–14, 2009, Dresden, GermanySearch in Google Scholar
10 Kiss, A.; Laurien, E.; Aszódi, A.: Numerical Simulation of a HPLWR Fuel Assembly Flow With Wrapped Wire Spacers. Proceedings of ICAPP 2008 Conference (Paper 8339), Anaheim, California, USA, June 9–12, 2008Search in Google Scholar
11 Laurien, E.; Wintterle, T.: On the Numerical Simulation of Flow and Heat Transfer within the Fuel-Assembly of the High-Performance Light-Water Reactor. KTH-Workshop on Modeling and Measurements of Two-Phase Flows and Heat Transfer in Nuclear Fuel Assemblies, Stockholm, Sweden, October 10–11, 2006Search in Google Scholar
12 Wagner, W.; Kruse, A.: The Industrial Standard IAPWS-IF97 for the Thermodynamic Properties and Supplementary Equations for other Properties. Properties of water and steam, Springer Verlag, Heidelberg, 1997Search in Google Scholar
13 Menter, F.et al.: CFD Best Practise Guidelines for CFD Code Validation for Reactor-Safety Applications. ECORA project, FIKS-CT-2001-00154, Brussels, Belgium (2002)Search in Google Scholar
14 Laurien, E.; Wintterle, T.: Secondary Flows in the Cooling Channels of the High-Performance Light-Water Reactor. Proceedings of ICAPP 2007 Conference (Paper 7089), Nice, France, May 13–18, 2007Search in Google Scholar
15 Waata, C. L.: Coupled Neutronics/Thermal-hydraulics Analysis of a High-Performance Light-Water Reactor Fuel Assembly. Doctoral thesis, FZKA 7233, July, 2006Search in Google Scholar
© 2010, Carl Hanser Verlag, München
