DOI QR코드

DOI QR Code

Introduction and Feasibility on a New Technology for the Pipe Wall Thinning Evaluation of Nuclear Power Plants

원전 배관감육 평가를 위한 새로운 기법의 도입 및 타당성

  • Received : 2014.04.18
  • Accepted : 2014.04.28
  • Published : 2014.04.30

Abstract

A huge number of carbon steel piping components installed in the secondary system of nuclear power plants are exposed to aging mechanisms such as FAC (Flow-Accelerated Corrosion), Cavitation, Flashing, and LDIE (Liquid Droplet Impingement Erosion). Those aging mechanisms can lead to thinning of the piping components. To manage the wall thinning degradation, most of utilities in the world predict the wall thinning rate based on the computational program such as CHECWORKS, COMSY, and BRT-CICERO, evaluate the UT (Ultrasonic Test) data, and determine next inspection timing, repair or replacement, if needed. There are several evaluation methods, such as band, blanket, and strip methods, commonly used for determining the wear of piping components from single UT inspection data. It has been identified that those single UT evaluation methods not only do not consider the manufacturing features of pipes, but also may exclude the data of the most thinned point when determining the representative wear rate of piping components. This paper describes a newly developed single UT evaluation method, E-Cross method, for solving above problems and introduces application examples for several pipes and elbows. It was identified that the E-Cross method using the length and width of UT data excluded the most thinned points appropriate as the single UT evaluation method for thinned piping components.

Keywords

References

  1. J. Horowitz, Recommendations for Controlling Cavitation, Flashing, Liquid Droplet Impingement Erosion, and Solid Particle Erosion in Nuclear Power Plant Piping Systems, EPRI 1011231, Final Report, p.2-1 (2004).
  2. K. M. Hwang, J. of Mech. Sci. and Technol, B (Korean), 35, 1105 (2011).
  3. D. Smith, Mentoring Guide for Flow-Accelerated Corrosion Engineers, EPRI 1022295, Technical Update, p.8-7 (2010).
  4. Y. H. Lee, Thickness Inspecting Data Analysis after 2 Operating Cycles for a New Constructed Nuclear Plant", The Corrosion Science Society of Korea, The CSSK 2013 Annual Fall Meeting and Symposium on Protective Coating & Stainless Steel Program, p.49, Jeju (2013).
  5. D. Poe and H. Crockett, CHECWORKSTM Steam/Feedwater, Application, Guidelines for Plant Modeling and Evaluation of Component Inspection Data, EPRI 1019176, Final Report, p.4-11 (2009).
  6. D. Poe, D. Ha, and J. Horowitz, CHECWORKSTM Steam/ Feedwater, Application, Guidelines for Plant Modeling and Evaluation of Component Inspection Data, EPRI 1009599, Final Report, p.4-15 (2004).