Step-Orifice Applied in Nuclear Piping System

Taking the EAS test pipeline in Daya Bay Nuclear Power Station as an example, this paper studies the method for the analysis of piping vibration caused by the cavitations and the design method by using the step-orifice to reduce the cavitations. Using the CFD method, the flow characteristics and pressure distribution around the orifice are studied to determine if the cavitations occurs in the downstream of the orifice. Finally, the cavitation number approximate criteria for step-orifice are adopted to redesign a new throttle orifice. It has been proved that the redesigned step-orifice can effectively reduce the piping vibration and noise.