Partitioned simulation of long and slender cylinders corresponding to nuclear fuel rods vibrating in axial flow

Currently generation IV nuclear reactors are being developed. One of the possible designs is the lead-cooled fast reactor, of which MYRRHA is a prototype. The aim of this study is to gain insight in the eigenmode characteristics of fuel rods immersed in axial flow. Current design practice is to use semi-empirical models to provide vibration characteristics. This study on the other hand takes the entire 3-dimensional flow field into account to determine the eigenmode characteristics. Therefore partitioned simulations are performed using the IQN-ILS algorithm on one empty fuel rod. Initially the rod is deformed according to an in-vacuo eigenmode which is then released in an unsteady FSI-simulation. Simulations are performed with both symmetric and periodic boundary conditions to analyze the effect of boundary conditions in the flow field .