Transient dynamic characteristics study on reactor coolant pump in variable working conditions

For the study of the transient hydraulic characteristics and internal flow mechanism of the reactor coolant pump from designed conditions to off-designed conditions, using CFX software to simulate the variable flow transient characteristics of reactor coolant pump impeller passageway. The results show that: during the flow transition, the radial force of the impeller doesn't rotate around the coordinates origin, but rotates around some point in the fourth quadrant, and radial forces of the guide vanes mainly distributes in the first and second quadrant, and radial forces of the volute completely distribute in the fourth quadrant. Because of the influence from the blade number, radial forces of the impeller and guide vanes are in obvious star distribution, meanwhile, because the pump body uses annular structure, the flow and velocity in the impeller passageway and the pressure distribution of the impeller export asymmetry radial force. During the transition to big flow, the radial force impact of the impeller and guide vane mainly shows in the direction of the offset and slightly decreasement of the change magnitude. The radial force on the volute moves down with the incensement of the flow, and the changes magnitude become larger. During the transition to small flow, radial forces bearing on impellers, guide vanes and the volute, whether on the size, direction or the change magnitude, have a significant change.