Flow-induced vibration in sodium-cooled fast reactor

The core of sodium fast breeder reactor (Na-FBR) comprises hexagonal slender structures arranged in a very confined manner. The flow of liquid sodium through the cavities and the hexagonal structures lead to complex fluid-structure interaction. To investigate the flow induced vibration, we performed large eddy simulations (LES) alongside the ongoing experimental efforts in French alternative energies and atomic energy commission (CEA), where the computational/experimental geometry consisted of a hexagonal prism, representing the fast breeder rector assembly (see Fig.1, also Sargentini et al. 2015).

The high-fidelity simulations are performed in two settings, namely, internal and external, where the external setting involves coupling of two standalone solvers for the flow (finite volume) and structure (finite element) simulations. On the other hand, the internal coupling assumes an elastically mounted structure that oscillates with a singe degree of freedom. To provide an insight on the confined flow features, the LES flow fields, the velocity and pressure magnitudes, are displayed in Fig. 2.