抄録
The operating head of the fast reactor fuel assembly plays an important role in balancing pressure, moderating pressure drop and reducing vibration, which has a significant impact on the safety of fast reactor. Furthermore, it has the function of fixing and snatching during the process of replacing and hoisting fuel assembly. At present, there is no uniform design standard of the operating head. In this study, the computational fluid dynamics (CFD) was used to investigate the flow characteristics of the closed and open operating head. The results show that the outlet hole at the top of the operating head can effectively balance the pressure inside the operating head, moderate the pressure drop and reduce the vibration to avoid harmful impact on the structure. In addition, with the increase of outlet-hole diameter, the flow performance has been significantly improved inside the open operating head, which enhances the heat transfer and avoids the potential safety risks caused by heat accumulation. Moreover, it is suggested that the structure design of fast reactor fuel assembly can be optimized using the open operating head with outlet-hole diameter in 30mm. In the engineering, the outlet hole provides a flow channel for discharging residual gas before the injection of sodium coolant for the first time.
