CHF Performance of Hybrid Mixing Vane Grid for a Nuclear Fuel Bundle

Conference · Sun Jul 01 04:00:00 EDT 2007

OSTI ID:21229281

Shin, Chang-Hwan; Chun, Tae-Hyun ^[1]; Choo, Yeon-Jun; Moon, Sang-Ki; Chun, Se-Young ^[2]

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1. LWR Fuel Development Division, Korea Atomic Energy Research Institute, 150 Dukjin-dong, Yuseong, Daejeon, 305-353 (Korea, Republic of)
2. Thermal-Hydraulic Safety Research Division, Korea Atomic Energy Research Institute, 150 Dukjin-dong, Yuseong, Daejeon, 305-353 (Korea, Republic of)

Numerous studies have shown that the mixing vanes of the spacer grids in a nuclear fuel rod bundle increase the Critical Heat Flux (CHF) significantly. The amount of the CHF enhancement depends strongly on the design of the mixing vanes such as the vane shape and vane bending angle. Recently a new mixing vane design was developed for an advanced spacer grid. It is called a Hybrid Mixing Vane. The main objective of this work is to evaluate the CHF performance of the hybrid vane grid and to compare it with that of a split vane grid. Three kinds of rod bundles were tested for the above objectives: no mixing vane grids, the hybrid mixing vane grids, and the split mixing vane grids. To measure the CHF data, 5x5 rod bundle experiments were conducted in the FTHEL (Freon Thermal Hydraulic Experiment Loop). Each experiment was performed by maintaining the following system conditions as constant: inlet pressure, inlet temperature, and mass flow rate. The experiments were performed in ranges of the inlet pressure, P{sub in} = 2000{approx}3000 kPa, mass flux, G = 1000{approx}3000 kg/m{sup 2}s, and inlet subcooling, {delta}h{sub in}= 10{approx}55 kJ/kg, which simulates the PWR operating conditions for a water equivalence through a fluid-to-fluid modeling. The CHF performances were compared with the data belonging to a PWR's operating conditions; a pressure of 2000{approx}3000 kPa and a mass flux of 1500{approx}3000 kg/m{sup 2}s. The average of the CHF increase for the hybrid mixing grids for 20 data sets is 18.2% higher than that for the no vane grids. While the average of the CHF increase for the split mixing vane grids for 20 data sets is 14.5% higher than that for the no vane grids. Consequently, the CHF performance of the hybrid mixing vane grid is superior by about 4% to that of the split mixing vane grid near the normal PWR operating conditions even under a longer grid span than usual. (authors)

• Research Organization: American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
• OSTI ID: 21229281
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
42 ENGINEERING
CRITICAL HEAT FLUX
DESIGN
FLOW RATE
FLUIDS
FUEL ELEMENT CLUSTERS
NUCLEAR FUELS
PERFORMANCE
PWR TYPE REACTORS
SIMULATION
THERMAL HYDRAULICS