Background: With the rapid growth in the non-nuclear area for industrial use of Computational fluid dynamics(CFD) which has been accompanied by dramatically enhanced computing power

the application of CFD methods to problems relating to Nuclear Reactor Safety(NRS) is rapidly accelerating. Existing research data have shown that CFD methods could predict accurately the pressure field and the flow repartition in reactor lower plenum.But simulations for the full domain of the reactor have not been reported so far. Purpose: The aim is to determine the capabilities of the codes to model accurately the physical phenomena which occur in the full reactor vessel. Methods:The flow field of the CPR1000 reactor which is associated with a typical pressurized water reactor(PWR) is simulated by using ANSYS CFX. The pressure loss in reactor pressure vessel

the hydraulic loads of guide tubes and support columns

and the bypass flow of head dome were obtained by calculations for the full domain of the reactor.The results were validated by comparing with the determined reference value of the operating nuclear plant(LingAo nuclear plant)

and the transient simulation was conducted in order to better understand the flow in reactor pressure vessel. Results: It was shown that the predicted pressure loss with CFD code was slightly different with the determined value(10% relative deviation for the total pressure loss)

the hydraulic loads were less than the determined value with maximum relative deviation 50%

and bypass flow of head dome was approximately the same with determined value. Conclusion: This analysis practice predicts accurately the physical phenomena which occur in the full reactor vessel

and can be taken as a guidance for the nuclear plant design development and improve our understanding of reactor flow phenomena.