Effects of corrosion-product particle deposition on flow-induced vibration of an LBE-cooled wire-wrapped fuel rod bundle

Corrosion-product particles generated in lead–bismuth eutectic (LBE) coolant may be retained on wire-wrapped fuel assemblies, and different particle-laden conditions associated with wall retention may modify local fluid excitation. A computational fluid dynamics–discrete phase model–flow-induced vibration (CFD-DPM-FIV) framework combining the shear stress transport (SST) k–ω model and one-way fluid–structure coupling is developed for a seven-pin LBE-cooled wire-wrapped fuel assembly to investigate the effects of particle mass flow rate, inlet velocity, and diameter. Under the reference particle condition, 73.87% of wall-trapped particles are located on the fuel-rod cladding surface, while 12.68% and 13.46% are located on the wire-wrap surface and hexagonal duct wall. Particle diameter and inlet velocity mainly alter the surface distribution of retained particles, whereas particle mass flow rate mainly changes the particle supply to the bundle. Although the global thermal–hydraulic parameters vary only slightly, the vibration response is sensitive to particle-retention conditions. Compared with the particle-free case, the high particle mass-flow-rate and large-particle cases increase the maximum total deformation from 85.208 μm to about 99.0 μm and the maximum von Mises stress from 0.2976 MPa to about 0.360 MPa. At the center-rod midspan, the fluctuating root-mean-square (RMS) displacement increases from 12.573 to about 22.96 μm in the X direction and from 33.774 to about 63.13 μm in the Z direction, while the dominant response frequency remains near 22 Hz. These results indicate that deposition-prone particle conditions can amplify the predicted FIV response before severe macroscopic blockage develops.