Advancements and validation of CFX for alternative reactor concepts

Currently, the coupling interface between ATHLET and ANSYS CFX for 1-D/3-D simulations was designed for water as working fluid only. It was therefore necessary to extend the interface to be applicable to other Generation-IV working fluids. The present report documents the respective development and presents obtained results. In a first step towards helium, an extension to the coupling interface between ATHLET and ANSYS CFX was made for one-phase steam simulations. This required the introduction of new variables and arrays in several subroutines in order to implement a data transfer of the new physical quantities between ATHLET and ANSYS CFX. Furthermore, first 1-D/3-D ATHLET ANSYS-CFX calculations with two coupling instances have been performed. To this aim, a quarter of a pipe was modeled with 10560 nodes. The pipe has been connected to an ATHLET loop. The explicitly coupled simulation of a mass flow increase in a closed loop resulted in physically plausible mass flow and temperature evolutions, respectively. The mass flow imposed by a pump first increased from 0 to 8 kg/s and kept constant afterwards. In the coupled simulation, pressure and mass flow oscillations have been observed.