Effect of Contacting Shapes on the Worn Area Properties of a Nuclear Fuel Rod in Room Temperature Air and Water

摘要

Fretting wear experiments were conducted to evaluate the effects of the contacting shapes of spacer grid springs on the wear behavior of a nuclear fuel rod in room temperature air and water. The main objective was to quantitatively compare the wear behavior of the nuclear fuel rod with the variation of the contacting spring shapes. The variation of the real worn area in the wear scar, the change in the wear volume and the maximum wear depth with the slip amplitude were calculated and measured through an optical micrometer and surface profilometry. The results of the wear tests showed that the wear volume and the maximum wear depth were sensitively affected by each spring shape with increasing slip amplitude and with a change of the test environment. From the analysis of the wear scar, it is possible to separate the size of the wear scar from the real worn area and the transferred one. In addition, we found that the wear volume has a linear relation with the real worn area rather than the size of the wear scar and this was only determined by using each spring shape even though the wear tests were carried out with different conditions. From the above results, it is possible to evaluate a wear resistant spring by using the correlation between the variation of the real worn area and the wear behavior at each spring shape.