The major role of spacer grids in the nuclear fuel assemblies is to properly locate and align the fuel rods at specific positions. Generally, each cell of the spacer grid contains two springs and four dimples. Each spring presses the fuel rod against two dimples, thereby restricting the relative motion of the fuel rods. If an excess wear, however, happens in the depth direction of the fuel rod due to a flowinduced vibration, the supporting ability of a spacer grid spring/dimple could be degraded because the fuel rod is only supported by the elastic deformation of the grid spring. So, the objective of this study is to compare the supporting ability and the wear resistance of two spacer grid springs. The discussion was focused on the necessity of a unit cell test rig, the variation of the contacting forces and the fretting wear behavior of the fuel rod.
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