Experimental investigation on the unsteady pressure pulsation and vibration of a nuclear pump test loop

The nuclear reactor coolant pump (RCP) is the key equipment of the Pressurized Water Reactor, of which the coolant circulation inherently brings flow fluctuation and, therefore, flow-induced vibration exists, which is detrimental to the safe and stable operation of nuclear power plants. Experiments were carried out on a nuclear pump test loop to investigate the characteristics of pressure pulsation and vibration under various rotational speeds and operational temperatures. Signals of pressure pulsation and vibration synchronously measured from the sensors located among the test loop and the bottom of the motor were analyzed by the Root Mean Square and the Fast Fourier Transform methods. Pronounced pressure pulsation peaks corresponding to the blade passage frequency and its higher harmonics are captured, and pressure pulsation amplitude variations are closely associated with the sensor positions and operating conditions. Vibration magnitude along the outlet direction of the nuclear RCP is the largest and increases with the increasing rotational speed but not the operating temperature. Finally, a coherent analysis was conducted between the vibration at the bottom of the motor and the unsteady pressure pulsation in the test loop. This study can provide meaningful scientific guidance in practical engineering applications.