Thermal hydraulic reactor core calculations based on coupling the CFD code ANSYS CFX with the 3D neutron kinetic core model DYN3D

In order to get the correct feedback on the core reactivity, analyses of postulated reactivity initiated accidents in nuclear reactors require the coupled solution of the neutron transport equation, the equations of heat conduction in the fuel and the heat and momentum transport in the coolant. The paper gives an overview on the coupling of the neutron kinetics code DYN3D with the general purpose fluid dynamics code ANSYS CFX which was carried out to improve the thermal hydraulic part of reactor dynamics simulations. Two steady state simulations of Convoi and VVER type reactors demonstrate that the coupled code system allows for analyses with more plausible results of coupled thermal hydraulics - neutron kinetics problems because three-dimensional coolant flow and heat transport can now be simulated.