Measurement of a velocity field in a pin bundles in FBR

It is important to advance safety and efficiency of the fast breeder reactor (FBR). A numerical prediction method of high accuracy and its validation with a simulated thermal flow field are indispensable. A wire-wrapped rod bundle system, which briefly simulated the fuel rods system in FBR, was built up in the experiments. The wire wrapped rods were made from Mexflon-material, of which refractive index was exactly same with that of water. The particle image velocimetry (PIV) was applied to measure the velocity field in the rod bundles, with variable flow rates and the temperature conditions. The aim of this study was to contribute to the certification of results of numerical simulation for the safety design of the FBR. (author)