• Title, Summary, Keyword: Acoustic Emission

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The Evaluation of Internal Leak in Valve for Power Plant Using Acoustic Emission Method (음향방출법에 의한 발전용 밸브 누설평가)

  • Lee, Sang-Guk;Lee, Sun-Ki;Lee, Jun-Shin;Lee, Wook-Ryun
    • Proceedings of the KSME Conference
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    • pp.1733-1739
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    • 2004
  • The objective this study is to estimate the feasibility of acoustic emission method for the internal leak from the valves in nuclear power plants. From the experimental results, it was suggested that the acoustic emission method for monitoring of leak was feasible. When the background levels are higher than the acoustic signals from leak, we can detect the leak analyzing the spectrum of the remainders which take the background noise from the acoustic signals.

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A Study on the Evaluation of Internal Leak in Valve for Nuclear Power Plant Using Acoustic Emission Method (음향방출법에 의한 원자력발전소 밸브내부 누설평가에 관한 연구)

  • Lee, Sang-Guk;Lee, Sun-Ki;Lee, Jun-Shin
    • Proceedings of the KSME Conference
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    • pp.284-289
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    • 2004
  • The objective this study is to estimate the feasibility of acoustic emission method for the internal leak from the valves in nuclear power plants. From the experimental results, it was suggested that the acoustic emission method for monitoring of leak was feasible. When the background levels are higher than the acoustic signals from leak, we can detect the leak analyzing the spectrum of the remainders which take the background noise from the acoustic signals.

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Study on the Real-Time Leak Monitoring Technique for Power Plant Valves (발전용 밸브누설 실시간 감시기술 연구)

  • Lee, S.G.
    • Journal of the Korea Society For Power System Engineering
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    • v.11 no.1
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    • pp.39-44
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    • 2007
  • The purpose of this study is to verify availability of the acoustic emission in-situ monitoring method to the internal leak and operating conditions of the major valves at nuclear power plants. In this study, acoustic emission tests are performed when the pressurized temperature water and steam flowed through glove valve(main steam dump valve) and check valve(main steam outlet pump check valve) on the normal size of 12 and 18". The valve internal leak monitoring system for practical field was designed. The acoustic emission method was applied to the valves at the site, and the background noise was measured for the abnormal plant condition. To improve the reliability, a judgment of leak on the system was used various factors which are AE parameters, trend analysis, frequency analysis, voltage analysis and amplitude analysis of acoustic signal emitted from the valve operating condition internal leak.

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Study on Evaluation of the Leak Rate for Steam Valve in Power Plant (발전용 증기밸브 누설량 평가에 관한 연구)

  • Lee, S.G.;Park, J.H.;Yoo, G.B.
    • Journal of the Korea Society For Power System Engineering
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    • v.11 no.1
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    • pp.45-50
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    • 2007
  • Acoustic emission technology is applied to diagnosis the internal leak and operating conditions of the major valves at nuclear power plants. The purpose of this study is to verify availability of the acoustic emission as in-situ diagnosis method. In this study, acoustic emission tests are performed when the pressurized high temperature steam flowed through gate valve(1st stage reheater valve) and glove valve(main steam dump valve) on the normal size of 4 and 8". The valve internal leak diagnosis system for practical field was designed. The acoustic emission method was applied to the valves at the site, and the background noise was measured for the abnormal plant condition. To improve the reliability, a judgment of leak on the system was used various factors which are AE parameters, trend analysis, signal level analysis and RMS(root mean square) analysis of acoustic signal emitted from the valve operating condition internal leak.

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Development of Diagnosis Technique for Converter Bearings by Using Acoustic Emission (음향방출기법을 이용한 전로베어링 안전진단 기술개발)

  • 박경조
    • Journal of the Korean Society of Safety
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    • v.18 no.2
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    • pp.6-15
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    • 2003
  • A method is presented for diagnosing the converter bearings by using acoustic emission. The flaking mechanism causing the large-scale bearing for furnace to flaw is investigated and a possibility of defect is verified by Finite Element method. he diagnosis logic is proposed fir detecting the flaw of a non-continuous rotating machine. It is proved that the acoustic emission energy can be used as a representative parameter for an acoustic event. Applying the method to the tilting bearings for steel mill in operation, the effectiveness of this logic is evaluated. It is shown that AE signal is generated only when the bearing is tilting, and the trend analysis can be focused upon this process.

Application of Acoustic Emission Technique for Bridge Cable Monitoring (교량 케이블 적용 강연선 모니터링을 위한 음향방출 기법 검토)

  • Kim, Ga-Young;Seo, Dong-Woo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.4
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    • pp.121-125
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    • 2018
  • This paper presents the assessment of 7-wire strand monitoring using acoustic emission technique for bridges. 7-wire strand is widely used construction materials to provide additional tensile force to bridges. PSC (PreStressed Concrete) bridge and cable-stayed bridge are representatives for such cases. However, as the bridge aging progresses recently, corrosion problems of strand are emerging. For this reason, various NDT (Non-Destructive Test) methods for cable inspection are being studied and applied to the field. One of the NDT methods, acoustic emission technique, is known as an effective technique to detect cable damage and breakage. In this study, to evaluate the applicability of acoustic emission technique to bridges, acoustic emission signals according to damage of the strand were acquired and analyzed by tensile test. Moreover, The optimal AE sensor type was selected for field application. As a result, it is considered that the acoustic emission technique will be able to detect corrosion breakage and signs of rupture.

A Study on the Frequency Analyzing of Leak Evaluation m Valve for Power Plant Using AE (AE법에 의한 발전용 밸브누설평가를 위한 주파수분석 연구)

  • LEE SANG-GUK
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • pp.360-364
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    • 2004
  • The objective of this study is to estimate the feasibility of acoustic emission method Jar the internal leak from the valves in nuclear power plants. The acoustic emission method was applied to the valves at the site, and the background noise was measured for the abnormal plant condition. From the comparison of background noise data with the experimental results as to relation between leak flow and acoustic signal, the minimum leak flow rates that am be detected by acoustic signal was suggested. When the background noise level are higher than the acoustic signal, the method described below was considered that the analysis the remainder among the background noise frequency spectrum and the acoustic signal spectrum.

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Acoustic Emission Application for Aerospace Composite Materials (항공용 복합재료에 대한 음향방출의 활용)

  • Lee, Sang-Ho
    • Journal of the Korean Society for Nondestructive Testing
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    • v.21 no.3
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    • pp.313-318
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    • 2001
  • To establish nondestructive test method for aerospace composite materials, various composite specimens were tested and analyzed using acoutic emission. The hit rate of acoustic emission closely was rotated with crack initiation and propagation. This report also presents defection capability of crack initiation pressure, initial crack active location, and crack propagation using acoustic emission.

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Measurement of Defects with Scanning Acoustic Microscope and Acoustic Emission (초음파 현미경 및 AE에 의한 결함 측정)

  • Choi, Man-Yong;Park, Ik-Gun;Han, Eung-Kyo
    • Journal of the Korean Society for Precision Engineering
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    • v.8 no.4
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    • pp.118-125
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    • 1991
  • Acoustic microscopy has attracted much interest recently as potential nondestructive evaluation technique for detecting and sizing defects of surface and sub-surface. Also acoustic emission testing method has been developed for detecting microcracks which is more than 30${\mu}m$ in length quantitatively on ceramics. In the present paper, acoustic emission during the four point bending test in hot-pressed sintered $Si_3N_4$ specimen which was stressed by thermal shock, has been measured by high sensitive sensing system. The surface and sub-surface cracks were detected by scanning acoustic micrscope of 800 MHz and conventional ultrasonic testing in C-scope image. The purpose was to investigate the location and size of cracks by SAM and AE technique, whose experimental data demonstrate good for detecting microcracks.

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