An analytical study on the pump-induced acoustic pressure in a pressurized water reactor

Abstract

A method of estimating the amplitude of acoustic pressures induced by the external coolant pump in the inlet pipe and the annulus of a pressurized water reactor simultaneously is presented. In the previous analytical study, it has been assumed that the pump excitation at the inlet nozzle is known prior to predict the pressure distribution in the annulus. To resolve this restriction, two separate regions are considered in the present study. First, by considering the inlet pipe separately and introducing the boundary operator method, a theoretical solution is developed that satisfies all boundary conditions imposed on the inlet pipe. The annulus region is analyzed by a three dimensional acoustic wave equation in cylindrical coordinate with a non-homogeneous boundary condition at the inlet pipe/annulus interface. Furthermore, it is possible to analytically determine the inlet nozzle pressure by coupling the solutions of the inlet pipe and the annulus from the pressure continuity at the inlet pipe/annulus interface. Agreement between the predicted values and test data is good for the inlet nozzle pressure.