A conceptual design study of a large-scale sodium-cooled fast reactor adopts a two-loop primary cooling system with large-diameter piping in order to reduce plant construction cost. In this design, one of issues is a flow-induced vibration behavior of the piping under a high Reynolds number of 10^7 order. To evaluate the piping integrity, it is necessary to obtain power spectrum densities of pressure fluctuations on the piping wall by a numerical unsteady flow simulation. In this study, the numerical simulation capability of Reynolds stress model and large-eddy simulation in the STAR-CD code has been investigated using the 1/3-scale hot-leg test data. Through the sensitivity analysis, the Reynolds stress model with appropriate analytical models has shown the best applicability to flow dynamics simulation in the short-elbow pipe.
