FLUID MIXING EXPERIMENTS WITH A WIRE WRAPPED 7-ROD BUNDLE FUEL ASSEMBLY
The use of a 7-rod bundle nuclear fuel element in a circular coolant tube results in distinct flow sub-channels. To allow maximum power generation in the rod bundle, it is necessary to overcome the effects of unbalance between the heat transfer surface and the coolant flow rates in these subchannels by forcing inter-channel mixing to occur. Spiral wire wraps on the individual rods of the bundle promote such mixing. Experiments were performed to determine the amount of fluid mixing that exists between flow channels within 7-rod bundle fuel elements. A coaxial piping arrangement was utilized to introduce a salt solution into the inner coolant channels of a 7-rod bundle placed in a circular tube while regular water was introduced into the outer coolant channels. The salt concentration was measured in samples of the outer channel stream at various distances along the rod bundle mixing length and the relative salt concentration in these samples was used to describe the effectiveness of 4 to 18 inch pitch wire wraps as coolart mixing promoters. Analytical relations were derived to relate the chemical mixing rates to bulk coolant temperature disparity between the inner and outer channel coolant streams under nuclear heating conditions. In this way, the temperature disparity between the inner and outer coolant streams was predicted as a function of wire wrap pitch. These relations can be combined with pressure drop data published previously to indicate that wire wrap pitches of 10 to 18 inches cause near optimum mixing conditions in seven rod bundles. (auth)
- Research Organization:
- General Electric Co. Hanford Atomic Products Operation, Richland, Wash.
- DOE Contract Number:
- AT(45-1)-1350
- NSA Number:
- NSA-17-034096
- OSTI ID:
- 4650942
- Report Number(s):
- HW-70178
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- United States
- Language:
- English
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