COMPUTER AIDED SEISMIC DESIGN ANALYSIS FOR A CENTRIFUGAL PUMP

Abstract

Stringent safety requirements for operation of nuclear power plants call for the design of equipment suitable for withstanding the seismic shocks. It has to be established that the equipment is capable of performing the required safety functions during and after the specified seismic event. The, parameters that represent the seismic qualification are the fundamental frequency, the stresses and the relative displacements. They are determined through the computer aided analysis on the model prepared for the system. The decision to declare the equipment qualified for the operation in the earthquake prone area is based on the comparison of these parameters with those which are allowable. In this dissertation an attempt has been made to ascertain seismic qualification of rotating machines (in particular, the centrifugal pump) by computer aided analysis. In addition, a number of relevant published papers are reviewed and important codes practiced in seismic design and analysis are summarized. The dissertation describes step by step procedure of seismic qualification by analysis, which includes determination of. natural frequencies in three mutually perpendicular directions, using the lumped mass technique and acceleration response spectra as the input; shaft deflection analysis to ensure the pump's operability in seismic event; and bolt assembly design analysis to ensure the structural . integrity of the pump and the driving motor in accidental condition. Although, at first glance, the approach described appears confined to, machines operating in nuclear power plants, the same can be applied in other fields of equally important operations such as fire stations, hospitals etc.