Abstract
The primary hot-leg piping with a large-diameter is designed with high coolant velocity (9m/s). To reduce thermal stress, the primary hot-leg piping with large diameter is designed to be thin. Hot-leg piping adopts an L-shaped short elbow. The turbulence generated by flow separation in the short elbow may raise a flow-induced vibration issue. It is necessary to evaluate and confirm the integrity of piping against the flow-induced vibration. In order to evaluate the integrity, evaluation method for random vibration based on PSD and correlation length of pressure fluctuation, which were measured by 1/3 scale hot-leg piping experiments under rectified flow, swirl flow and defected flow, was developed. In this paper, a summary of the random vibration evaluation method, a scope of application, pressure fluctuation characteristics used for this method and a safety margin are described. Flow induced vibration of a primary circuit hot-leg piping can be evaluated with this random vibration evaluation method conservatively.
