Cause Analysis and Solution of Main Steam Pipe Vibration in a Nuclear Power Plant

Abstract

During the power increase test and full power operation, a nuclear power plant (NPP) found that the noise in the main control room (MCR) exceeded the design target value. After measurement, the vibration of the main steam pipe and its transmission to the MCR through the supports and penetrations are considered as one of the main reasons for the excessive noise in the MCR. In view of this situation, this paper uses the fluid dynamics code and acoustic analysis code to analyze the flow field and sound field of the main steam pipe in the flow-sound coupled analysis method. Acoustic resonance is found at the branch pipe of the main steam safety valve and in the cavity of the main steam isolation valve (MSIV), which is the main cause for the main steam pipe vibration. Considering the causes for the main steam pipe vibration, the MCR noise can be reduced by vibration source control, transmission path control and other means.