Acoustic pressure pulsations in pressurized water reactors

This paper is an examination of pressure pulsations within a PWR resulting from circulating pump excitations, Evaluation of these pulsations are necessary in determining the structural integrity of the reactor internals. Previously published solutions involving the coolant annulus were formulated by the use of an equivalent body force to circumvent the complexities of a time-dependent mixed-value boundary condition problem. However, due to divergent physical arguments concerning the correct form of the body force, different solutions were obtained. In addition these publications are based upon assumptions regarding the value of the inlet pressure (i.e. pressure at the inlet pipe/coolant annulus interface). This analysis addresses the following two problems: 1. Derivation of a theoretical solution that resolves discrepancies between varying physical arguments. 2. Analytical determination of the inlet pressure. The solution involves examination of two separate regions: 1. The inlet pipe which includes the pump, inlet pipe and inlet pipe/coolant annulus interface is described by a one-dimensional acoustic wave equation with time-dependent non-homogeneous boundary conditions. 2. The coolant annulus is described by a three-dimensional acoustic wave equation in cylindrical coordinates with a non-homogeneous boundary condition at the inlet pipe/coolant annulus interface. The remaining boundary conditions are assumed to be homogeneous. (orig.)