Abstract
For the thermal design of supercritical water reactors, it is necessary to develop an analysis method to correctly predict turbulent heat transfer characteristics in subchannels of fuel bundles. Spacers are set into the subchannels to keep a distance between adjacent fuel rods. The turbulent heat transfer generally enhances by reduction of cross-sectional area in the subchannels due to existence of the spacers. However, since thermo-physical properties of supercritical fluids drastically changes at the vicinity of the pseudocritical point, enhancement of the turbulent heat transfer depends on the thermal design. Then, the Japan Atomic Energy Agency is developing an analysis method to predict thermal-hydraulic characteristics of the supercritical fluids. The heat transfer calculations were performed under the condition of a subchannel with a specer surrounded by four fuel rods. The present study describes an increase of the turbulent heat transfer coefficient in the subchannel.
