Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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Analysis of pipe thickness reduction according to pH in FAC facility with In situ ultrasonic measurement real time monitoring

  • Oh, Se-Beom (Material Safety Technology Development Division, Korea Atomic Energy Research Institute) ;
  • Kim, Jongbeom (Material Safety Technology Development Division, Korea Atomic Energy Research Institute) ;
  • Lee, Jong-Yeon (Material Safety Technology Development Division, Korea Atomic Energy Research Institute) ;
  • Kim, Dong-Jin (Material Safety Technology Development Division, Korea Atomic Energy Research Institute) ;
  • Kim, Kyung-Mo (Material Safety Technology Development Division, Korea Atomic Energy Research Institute)
  • Received : 2021.04.05
  • Accepted : 2021.07.30
  • Published : 2022.01.25
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Abstract

Flow accelerated corrosion (FAC) is a type of pipe corrosion in which the pipe thickness decreases depending on the fluid flow conditions. In nuclear power plants, FAC mainly occurs in the carbon steel pipes of a secondary system. However, because the temperature of a secondary system pipe is over 150 ℃, in situ monitoring using a conventional ultrasonic non-destructive testing method is difficult. In our previous study, we developed a waveguide ultrasonic thickness measurement system. In this study, we applied a waveguide ultrasonic thickness measurement system to monitor the thinning of the pipe according to the change in pH. The Korea Atomic Energy Research Institute installed FAC-proof facilities, enabling the monitoring of internal fluid flow conditions, which were fixed for ~1000 h to analyze the effect of the pH. The measurement system operated without failure for ~3000 h and the pipe thickness was found to be reduced by ~10% at pH 9 compared to that at pH 7. The thickness of the pipe was measured using a microscope after the experiment, and the reliability of the system was confirmed with less than 1% error. This technology is expected to also be applicable to the thickness-reduction monitoring of other high-temperature materials.

Keywords

Acknowledgement

This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (2017M2A8A4015158).

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