Analysis of the Degradation Tendency of NPP Cables Using a Wireless Cable Indenting Robot

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 nuclear power plant, 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 non-destructive and requires short testing time and small sized equipment. In order to address the problems with 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 light-weight 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, which are mechanical and electrical hardware parts and remote-control part. In order to analyze the degradation tendency of the cable, we prepared four thermally aged specimens and one un-aged specimen. Using the developed robot, we measured the modulus of the cable jacket of each specimen. The test data showed that the modulus of the cable jacket increased linearly as the accelerated aging time increased. From these results, we can analyze the degradation trends pertaining to cables installed in nuclear power plant according to the operation period.

• Periodical: Applied Mechanics and Materials (Volumes 284-287)
• Pages: 1749-1753
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.284-287.1749
• Online since: January 2013
• Authors: Kyung Nam Jang, Jong Soeg Kim, Sun Chul Jeong, Kyung Heum Park, Sung Yull Hong
• Keywords: Condition Monitoring, Degradation Tendency, Indenting Test

References

[1] IEEE Std 323-2003: IEEE Standard for Qualifying Class 1E Equipment for Nuclear Power Generating Stations, IEEE Power Engineering Society, (2003).

DOI: 10.1109/ieeestd.1983.82408

[2] IEEE Std 383-2003: IEEE Standard for Qualifying Class 1E Electric Cables and Field Splices for Nuclear Power Generating Stations, IEEE Power Engineering Society, (2003).

DOI: 10.1109/ieeestd.2004.94567

[3] Regulatory Guide 1. 211: Qualification of Safety-Related Cables and Field Splices for Nuclear Power Plants, U.S. Nuclear Regulatory Commission, (2009).

[4] Draft Regulatory Guide DG-1240: Condition Monitoring Program For Electric Cables Used In Nuclear Power Plants, U.S. Nuclear Regulatory Commission, (2010).

[5] EPRI: Cable Indenter Aging Monitor, EPRI NP-7348, Electric Power Research Institute, (1991).

[6] J. S. Kim: Evaluation of cable life based on condition monitoring, 01 fall meeting of Korean nuclear society, (2001).