Laminar Hydraulic Analysis of a Commercial Pressurized Water Reactor Fuel Assembly (NUREG/CR-7144, SAND 2008-3938)

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Publication Information

Manuscript Completed: August 2008
Date Published: January 2013

Prepared by:
E. R. Lindgren and S. G. Durbin

Sandia National Laboratory
Albuquerque, NM 87185

G. A. Zigh, NRC Project Manager

NRC Job Code Y6758

Prepared for:
Division of Systems Analysis
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington DC 20555-0001

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To the knowledge of the authors, these studies are the first hydraulic characterizations of a full length, highly prototypic 17×17 pressurized water reactor (PWR) fuel assembly in low Reynolds number flows. The advantages of full scale testing of prototypic components are twofold. First, the use of actual hardware and dimensionally accurate geometries eliminates any issues arising from scaling arguments. Second, many of the prototypic components contain intricacies by design that would not be reproduced by using simplified flow elements. While this approach yields results that are inherently specific to the fuel assembly under testing, the differences in commercial designs are considered minor, particularly when considering the hydraulics of the entire assembly.

This report summarizes the findings of the pressure drop experiments conducted using a highly prototypic PWR fuel assembly. The stated purpose of these investigations was to determine hydraulic coefficients, namely frictional loss coefficient (SLAM ) and inertial loss coefficient Σk values, for use in determining the hydraulic resistance in these assemblies within various numerical codes. Additionally, velocity profiles were acquired to estimate the partitioning of flow through the bundle and annular regions within the assembly. The apparatus was tested in the laminar regime with Reynolds numbers spanning from 10 to 1000, based on the average assembly velocity and hydraulic diameter.

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