Research on Cooperative Design of Anti-Hangup and Thermal Performance of Spacer Grid

Spacer grid is an important part of the fuel assembly skeleton structure, whose main function is to clamp and locate the fuel rods. The anti-hangup performance and thermal performance also shall be considered. Based on the feedback of the operation experience of the mainstream fuel assembly, this paper uses the three-dimensional modeling software (UG) to simulate the relative motion of the grid, analyzes the causes of the hangup, and makes it clear that the continuous arrangement of the outer strip guide vane can effectively improve the anti-hangup performance, which is verified by the spacer grid hangup test; Through the computational fluid dynamics (CFD) simulation analysis of the side cell where the spacer grid is located, it is found that the continuous arrangement of guide vanes based on the traditional anti-hangup design is not conducive to the thermal performance between adjacent grids; On this basis, a scheme of alternating-height arrangement of guide vanes is designed. Theoretical analysis and experimental verification results show that the scheme realizes the cooperative design of anti-hangup and thermal performance of the fuel assembly spacer grid.