WJNST  Vol.3 No.4 , October 2013
Development of Safety Factors for the UT Data Analysis Method in Plant Piping
ABSTRACT

There are several thousand piping components in a nuclear power plant. These components are affected by degradation mechanisms such as FAC (Flow-Accelerated Corrosion), cavitation, flashing, and LDI (Liquid Droplet Impingement). Therefore, nuclear power plants implement inspection programs to detect and control damages caused by such mechanisms. UT (Ultrasonic Test), one of the non-destructive tests, is the most commonly used method for inspecting the integrity of piping components. According to the management plan, several hundred components, being composed of as many as 100 to 300 inspection data points, are inspected during every RFO (Re-Fueling Outage). To acquire UT data of components, a large amount of expense is incurred. It is, however, difficult to find a proper method capable of verifying the reliability of UT data prior to the wear rate evaluation. This study describes the review of UT evaluation process and the influence of UT measurement error. It is explored that SAM (Square Average Method), which was suggested as a method for reliability analysis in the previous study, is found to be suitable for the determination whether the measured thickness is acceptable or not. And, safety factors are proposed herein through the statistical analysis taking into account the components’ type.


Cite this paper
H. Yun, K. Hwang and C. Lee, "Development of Safety Factors for the UT Data Analysis Method in Plant Piping," World Journal of Nuclear Science and Technology, Vol. 3 No. 4, 2013, pp. 143-149. doi: 10.4236/wjnst.2013.34024.
References
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[2]   J. Horowitz, “Guidelines for Plant Modeling and Evaluation of Component Inspection Data,” Final Report, Electric Power Research Institute 1009599, Palo Alto, 2004, pp. 4.1-4.4.

[3]   J. Horowitz, “Statistical Methods for Analysis of Multiple-Inspection Flow-Accelerated Corrosion Data,” Final Report, Electric Power Research Institute 1019175, Palo Alto, 2011, pp. 3.3-3.5.

[4]   H. Yun and K. M. Hwang, “Reliability Analysis of UT Measurement for Evaluating Pipe Wall Thinning in Nuclear Power Plants,” The Corrosion Science Society of Korea, Busan, 2012.

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[8]   Jeffrey Horowitz, “Development of an Averaged Pointto-Point Method for Inspection Data,” Technical Update, Electric Power Research Institute 1020528, Palo Alto, 2010, pp. 1.1-1.3.

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