Mixing vanes can enhance the critical heat flux of fuel assemblies by generating vortices. Current studies primarily focus on the optimized design of traditional mixing vanes made of zirconium alloy and does not take into account the impact of mixing vanes on fretting wear of fuel rods.

This study aims to propose a novel type of mixing vane made of shape memory alloys to address the micro motion abrasion problem of fuel rods.

The two-way fluid-structure-thermal coupling analysis was employed to simulate the flow field distribution, pressure drop loss and fuel rod stress under a new type of mixing vane. Then, a nonlinear vibration model of fuel rod force with mixing vane made of shape memory alloys was established. Finally, a comparative analysis was conducted on the impact of different mixing vanes on the fretting wear power between fuel rods and the spacer grids.

The results indicate that shape memory alloys mixing vanes experience a similar pressure loss compared to traditional mixing vanes; the enhanced heat transfer effect increases with the maximum bending angle of the mixing vanes. Simultaneously, the fretting wear power between fuel rods and the spacer grids increases with the bending angle of the mixing vanes.

Shape memory alloys mixing vanes do not generate additional pressure loss while strengthening heat transfer between fuel rods and coolant.