Numerical simulation investigations on the flow induced vibration of a nuclear fuel rod with relaxed clamping structures

Grid-to-rod fretting (GTRF) wear is an important mechanism of nuclear breakage and fuel failure, which relates to the multi-physics field of fluid, structure, and irradiation. In this work, numerical simulation on the flow induced vibration of a nuclear fuel rod with relaxed clamping structures under the irradiation effect has been investigated by ANSYS FLUENT and ANSYS Workbench. The user's defined irradiation creep strain model is imported by secondary development tool, User Programmable Features (UPF). The result showed that the clamping of the spacer grid may become failure when the rod is applied by the fluid force with the clamping structures under the irradiation effect, and that the response of the rod is not evident due to the small fluid excitation. More promising results may be obtained if a more reliable inlet data or physical properties about wear is input.