Background: In the design of AP1000

Reactor Coolant Pump（RCP） is welded directly to the Steam Generator（SG） channel head.But this design makes the flow field in the SG channel head and RCP inlet complex and there may be vortex in this flow field for which reason the SG outlet resistance will increase and affect the long-term steady operation.Purpose: For this issue

some companies made tests on it.But the cost of test is high and the applicability of the test result is limited.If the parameters or components size changed a little

the test result will be no longer applicable.This article aims to find a way to solve this problem.Methods: This article considers using PumpLinx

a 3-D CFD flow field analysis software to analyse the SG and RCP coupled flow field.First

Pro/ENGINEER is applied to establish the 3D model of SG channel head with two RCPs welded to it and then establish mesh in PumpLinx and then analyze the problem in PumpLinx with Dynamic Mesh method.Results: The flow filed varying condition of SG-RCP coupled part from RCP rotation beginning to steady operation and the vortex condition after steady operation are obtained so as to support plant design.Conclusions: PumpLinx is suitable for AP1000 reactor coolant pump flow field CFD analysis.