“Experimental and Analytical Investigation of a Main Nuclear Coolant Pump,”
This article deals with the dynamic and static analysis of a vertical motor driven main coolant pump using transfer matrix and finite element methods on a microcomputer. This particular class of vertical motor water pump has experienced thermal cracking near the pump bearing bracket support. The object of the study was to obtain a computer model which matched the experimental data and to examine the possibility that static and dynamic loads on the motor-pump system could increase the rate of crack propagation. A critical speed analysis of the motor-pump system with casing effects was performed using the transfer matrix method. These mode shapes matched experimentally determined data. A finite element model was developed using MSC/PAL2 which gave excellent agreement with the transfer matrix analysis. Using the finite element model, the axial and torsional natural frequencies of the pump were also determined. The stresses at the bearing cartridge were analyzed under various combinations of axial, radial and torsional moments. It was concluded that the combined action of torsional and radial loading could enhance the rate of crack propagation observed in this class of pump.