Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
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Detection of Cracks in feeder Pipes of Pressurized Heavy Water Reactor Using an EMAT Torsional Guided Wave

EMAT의 유도초음파 비틀림 모드를 이용한 가압중수로 피더관의 균열 검출

  • Cheong, Yong-Moo (Nuclear Materials Technology Division, Korea Atomic Energy Research Institute) ;
  • Kim, Sang-Soo (Nuclear Materials Technology Division, Korea Atomic Energy Research Institute) ;
  • Lee, Dong-Hoon (Nuclear Materials Technology Division, Korea Atomic Energy Research Institute) ;
  • Jung, Hyun-Kyu (Nuclear Materials Technology Division, Korea Atomic Energy Research Institute)
  • 정용무 (한국원자력연구소 원자력재료기술개발부) ;
  • 김상수 (한국원자력연구소 원자력재료기술개발부) ;
  • 이동훈 (한국원자력연구소 원자력재료기술개발부) ;
  • 정현규 (한국원자력연구소 원자력재료기술개발부)
  • Published : 2004.04.30
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Abstract

A torsional guided wave mode was applied to detect a crack in a pipe. An array of electromagnetic acoustic transduce. (EMAT that can generate and receive torsional guided ultrasound with the frequency of 200kHz was designed and fabricated for testing a pipe of 2.5 inch diameter Artificial notches with various depths were fabricated in a bent feeder pipe mock-up and the detectability was examined from the distance of 2m of the specimen. The axial notches with the depth of 5% of wall thickness were successfully detected by a torsional mode (T(0,1)) generated by the EMAT However, it was found that the depth of defects was not related to the signal amplitude.

배관에서의 균열 탐지를 위해서 비틀림 모드 유도초음파 검사법을 적용하였다. 배관에서 비틀림 모드의 생성 및 수신을 위하여 배열형 전자기음향 탐촉자 (EMAT, electromagnetic acoustic transducer)를 설계, 제작하였다. 직경 2.5 인치의 배관에 대해 주파수 2000kHz의 비틀림 모드 유도초음파를 적용하였으며 가진용으로 4개의 배열형 EMAT를 제작하였으며, 별도의 수신용 EMAT를 설계 제작하였다. 실제 중수로 피더관 mock-up에 대해 곡관부에 다양한 깊이의 인공 결함을 가공한 뒤 약 2 hi 거리에서 각각의 탐지능을 실험하였다. 결함 깊이가 관 두께 대비 5% 인 경우에도 결함 신호를 탐지할 수 있었으나 결함의 깊이와 신호 진폭과의 관계성은 나타나지 않았다.

Keywords

References

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