Monometallic positioning grillwork for reducing fuel rod position damage and pressure loss

Abstract

The invention belongs to the technical field of nuclear power station pressurized water reactor fuel assemblies, and particularly discloses a single-metal positioning grillwork for reducing fuel rod position damage and pressure loss, the single-metal positioning grillwork is of a square lattice cell structure and is formed by vertically inserting two groups of strips, a clamping structure is arranged in the opposite direction of each lattice cell, and each clamping structure comprises a spring and a rigid bulge; the spring is of an arch structure formed by directly stamping lattice cell strips and protruding out of the surfaces of the strips, and the spring is arranged in the axial direction of the fuel rod. The springs are longitudinally arranged along the lattice cells of the grillwork, the springs are directly punched and formed from the wall surfaces of the strips, the whole grillwork is of a single-metal structure, compared with a double-metal grillwork, nickel-based spring materials are reduced, absorption of thermal neutrons can be reduced, the neutron economy of the fuel assembly is improved, meanwhile, the springs are directly punched and formed, and the manufacturing process is simplified. The springs are arranged in the axial direction, the continuous guiding effect is achieved in the fuel rod assembling process, and scratches to the surfaces of the rods can be reduced.

Description

technical field [0001] The invention belongs to the technical field of nuclear power plant pressurized water reactor fuel assemblies, and in particular relates to a single metal positioning grid for reducing fuel rod position damage and pressure loss. Background technique [0002] At present, nuclear power fuel assembly positioning grids are divided into bimetallic grids (such as French AFA series components) and single metal grids (such as Westinghouse AP1000 fuel assemblies) in terms of material types. The bimetallic grid uses zirconium alloy as the strip and nickel-based alloy as the spring material. The advantage of nickel-based alloys is high strength, but the disadvantage is that the neutron absorption cross section is large, which is not conducive to the neutron economy of fuel assemblies. The use of a single metal grid is beneficial to the neutron economy of the core, and is one of the development directions of the grid. Westinghouse AP1000 component lattice spring...

AI Technical Summary

Problems solved by technology

Westinghouse AP1000 component lattice spring is punched and formed from the cell strip wall. The spring structure is similar to the inclined rigid convex, which solves the application of single metal spring. The disadvantage is that the rigid convex edge is still encountered in the process of pulling the fuel rod. Conducive to the protection of the surface of the rod during the rod drawing process

In addition, the stiffness of the resulting spring is relatively large, the spring compression stroke is short, and the influence of manufacturing tolerances is relatively sensitive

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