Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
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Development of New ECT Probe Separating the Permebility Variation Signal in the SG Tube

증기발생기 전열관의 투자율 변화신호 분리를 위한 신형 탐촉자 개발

  • Published : 2008.02.28
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Abstract

A new ECT probe to separate the ECT signal distortion due to PVC (permeability variation clusters) and ordinary defects created in SG tubes has been developed. The hystersis loops of PVC which are extracted from retired SG (steam generator) tubes of Kori-1 NNP were measured. The tensile tests were performed to identify the mechanism of PVC creation. The conditions detecting the PVC created in 56 tubes were investigated using computer simulation, and the signal processing circuits were inserted in the probe for the digital signal transmission. The new Probe can measure and separate the PVC signal which is created in the SG tubes, and also measures the defects in Ni-sleeving part of SG tubes. furthermore the new ECT probe can measure the defects as fast as bobbin probe, and enhance the testing speed as well as reliability of the defect detection of SG tubes.

증기발생기 전열관에 생성되는 투자율변화에 의해 야기되는 신호왜곡 문제를 해결하기 위한 새로운 탐촉자를 개발하였다. 고리 1 호기 폐전열관에 생성된 자성상을 분리하여 자기이력곡선을 측정하였으며, 자성상이 생성되는 원인을 규명하기 위하여 고온 인장 시험을 수행하였다. 전산모사를 이용하여 탐촉자의 자정상 탐지조건을 결정하였으며, 디지털 신호전송을 위하여 신호처리용 전자회로를 소형화하여 탐촉자 속에 삽입하였다. 본 연구에서 개발된 신형 탐촉자를 이용하여 PVC 신호와 니켈 슬리빙 부위의 결함을 측정하였다. 신형 탐촉자는 보빈 탐촉자와 같이 고속으로 결함을 측정 할 수 있으며, 증기발생기 전열관의 탐상속도와 결함 탐지의 신뢰성을 증진시킬 수 있다.

Keywords

References

  1. Youn Park and Jin Ho Lee, 'Safety review on recent steam generator tube failure in Korea and lessons learned,' Transations of the 17th International Conference on Structural Mechanics in Reactor Technology (SMiRT17), Prague, Czech Republic, August 17-22, (2003)
  2. 증기발생기 연구협의회, '울진4호기 SGTR 원인 평가 및 대책', 증기발생기 안전성 Workshop, Nov. 6, (2002)
  3. Young-Kil Shin, Yun-Tai Lee and Myung-Ho Song, 'Comparison of absolute and differential ECT signals and tube spport plate in steam generator,' Journal of the Korean Society for Nondestructive Testing, Vol. 25, No. 3, pp. 201-208, (2005)
  4. ASTM E572, Standard practice for electromagnetic examination of nickel and nickel alloy tubular products, pp. 331, (1985)
  5. S. Takahashi, Y. Sato, Y. Kamada and T. Abe, 'Study of chromium depletion by magnetic methods in Ni-based alloys,' Journal of Magnetism and Magnetic Materials, Vol. 269, P. 139, (2004) https://doi.org/10.1016/S0304-8853(03)00584-5
  6. R. Palanisamy and W. Lord, 'Prediction of eddy current signals for nondestructive testing of condenser tubing,' IEEE-Trans on Mag., Vol. Mag-19, No. 5, pp. 2213, (1983)
  7. Ansoft Corp., 225 West Station Square, Suite 200, Pittsburg, PA 15219, USA; web site www.ansoft.com
  8. 정선영, 손대락, 유권상, 박덕근, '증기발생기 전열관의 비파괴 탐상용 차등형 와전류 탐촉자 개발', 한국자기학회지, Vol. 15, No. 5, pp. 292-297, (2005) https://doi.org/10.4283/JKMS.2005.15.5.292
  9. E. L. Hall and C. L. Briant, 'The microstructural response of mill-annealed and solution annealed Inconel 600 to heat treatment,' Matall. Trans. A, 16A, 1225, (1985)
  10. 정선영, 손대락, 유권상, 박덕근, 'Inconel 600의 강자성상 비파괴 검사에 관한 연구', 한국자기학회 2004년도 동계연구발표회 논문개요집, pp. 40-42, (2005. 12)
  11. J. J. Kai, C. H. Jsai, T. A. Hwang and M. M. Liu, 'The effects of heat Treatment on the sensitization and SCC behavior of Inconel 600 Alloy,' Metallurgical Trans. V. 20A, pp. 1077, (1989)
  12. Dh. Berge, J. R. Panati, 'Materials requirements for pressurized water reactor steam generator tubing,' Nucl. Technology, Vol. 55, pp. 88, (1981) https://doi.org/10.13182/NT81-A32833