Verification of the Viability of Equipotential Switching Direct Current Potential Drop Method for Piping Wall Loss Monitoring with Signal Sensitivity Analysis

posted Apr 16, 2013, 11:07 PM by Seunghyun Kim   [ updated Apr 16, 2013, 11:07 PM by Seung Chang Yoo ]
K. H. Ryu, I. S. Hwang and J. H. Kim
Journal of the Korean Society for Nondestructive Testing 28(2) (2008) 191-198
Flow accelerated corrosion (FAC) phenomenon of low alloy carbon steels in nuclear power plant has been known as one of major degradation mechanisms. It has a potential to cause nuclear pipe rupture accident which may directly impact on the plant reliability and safety. Recently, the equipotential switching direct current potential drop (ES-DCPD) method has been developed, by the present authors, as a method to monitor wall loss in a piping. This method can rapidly monitor the thinning of piping, utilizing either the wide range monitoring (WiRM) or the narrow range monitoring (NaRM) technique. WiRM is a method to monitor wide range of straight piping, whereas NaRM focuses significantly on a narrow range such as an elbow. WiRM and NaRM can improve the reliability of the current FAC screening method that is based on computer modeling on fluid flow conditions. In this paper, the measurements by ES-DCPD are performed with signal sensitivity analyses in the laboratory environment for extended period and showed the viability of ES-DCPD for real plant applications.