Transient structural load characteristics of reactor coolant pump rotor system in rotor seizure accident

Abstract

The serviceability of reactor coolant pump (RCP) under extreme conditions is essential assurance to prevent nuclear accidents. Among them, the RCP rotor seizure accident is classified as Type IV nuclear accident condition. This paper mainly studies the transient structural load characteristics of the RCP in rotor seizure accident, and reveals the radial and axial loads of the RCP impeller in the transient process of the rotor seizure accident, as well as the typical area stress distribution, transient dynamic stress and other change laws of the entire rotor. In this paper, the mathematical model of transient flow and speed under rotor seizure conditions is first established based on the rotor seizure test, which is the boundary condition of the calculation of flow-solid coupling, and then the structural module in Workbench is used to analyze the structural characteristics of the rotor in the transient process of rotor seizure condition. The study found that there will be three obvious “impact radial loads” in the transition process of rotor seizure, which are in the initial stage and the mid to late stage of the rotor seizure condition respectively. The transient radial load variation law is similar under different rotor seizure degrees, and the dynamic stress of the monitoring point at the inlet side of the impeller blade has the greatest difference, the closer the monitoring point is to the outlet of the blade, the later the dynamic stress recovery time and the lower the dynamic stress value at the inflection point.