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In this study, fretting wear tests of nuclear fuel rods have been performed by using 1x1 unit cell of a spacer
grid in high temperature and pressure distilled water conditions. The objectives are to examine the variation of
fuel rod traces with increasing number of fretting cycles and to evaluate its effect on the applied work-rate at
each spring and dimple specimen. It is apparent that the impact force at each specimen was independently
changed regardless of the same initial contact condition. In addition, the rod traces at contact region show
irregular shapes at initial stage and then gradually changed to biased circular shapes. This is because both
discontinuous regions and stiffness difference between spring and dimple specimen could affect a deformed
circular rod motion and finally seem to be determine the preferred shape of the rod motion. Based on the test
results, the relationship between the variation of rod traces and applied work-rate was discussed in detail.