Study on the characteristics of the nuclear reactor coolant pump during the process-divided start-up period

Abstract

The nuclear Reactor Coolant Pump (RCP) is the main spinning equipment in the primary cooling system of the pressurized water reactor. The current start-up period of the RCP includes the variation of operating pressure, temperature, and rotating speed. A Computational Fluid Dynamics (CFD) model of a whole primary system is used to investigate the performance change and transient effects during this period. Results show that the start-up power and force could be limited by dividing the start-up period into processes. Meanwhile, the impeller blade sweeps over the guide vane, leading to pressure pulsation and impeller axial force fluctuation. This Blade Passing Frequency is dominant in the whole pulsation frequency band and is varying linearly with the rotating speed. The medium density and viscosity decline with temperature rise, further leading to a significant decrease in motor power and fluid-induced force, which is the main aim to apply process-divided start-up.