Kyung-Nam Jang, Jong-Soeg Kim, Sun-Chul Jeong, Kyung-Heum Park and Sung-Yull Hong*
The Journal of Mechanical Science and Technology, vol. 26, no. 9, pp.2735-2740, 2012

Abstract : In nuclear power plants, there are many cables that perform safety-related functions. These cables should implement condition monitoring during the operation period in the NPP, in order to assess the remaining qualified life and extend the qualified life. In this study we focused on the indenting method, which can measure the hardness of the cable jacket. This method is selected because it is nondestructive and requires short testing time and small sized equipment. In order to address the problems of the existing indenting test equipment, we developed new indenting test equipment, which could automatically move on the surface of the object cable. The newly developed equipment is designed for a small-sized and lightweight robot using wireless communication in order to implement condition monitoring in a harsh environment or locations that are inaccessible to the tester. The developed wireless cable indenting robot is composed of three parts, mechanical and electrical hardware parts and remote-control part. In order to verify accuracy improvement of indenting test data, an indenting test for cable specimens using both existing indenting test equipment and wireless cable indenting robot was performed. Analysis of the indenting test results shows that the accuracy of the results obtained using the wireless cable indenting robot is improved remarkably.

Keyword : Condition monitoring; Safety-related cable; Indenting test; Wireless communication