• Proceedings of the KSME Conference
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• 2005.11a
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• pp.100.1-100.1
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• 2005

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.181-182
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• 2014

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.220.2-220
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• 1999

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.10
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• pp.795-801
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• 2014

Steam leakage is one of the major issues for the structural fracture of pipes of nuclear power plants. Therefore a method to inspect a large area of piping systems quickly and accurately is needed. Recently, the research detecting the steam leakage by using camera image is introduced. However, this method has a disadvantage. If a camera oscillates, it cannot detect a steam leakage exactly. In this paper, the technique that reduces the error due to a camera shaking is proposed. To verify the proposed method, we have performed the experiments for the oil leakage experiments. The results show that the technique can calibrate the error due to camera shaking.

• Journal of 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.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.16 no.2
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• pp.25-34
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• 2020

As leakage in nuclear power plants could cause a variety of problems, it is very critical to monitor leakage from the safety point of view. Accordingly, a new type of leak detection system is currently being developed and flow characteristics of the sampling and transportation system are investigated by using numerical analysis as a part of the development process in this study. The results showed that the steam mass fraction varied according to the effect of the gap between the insulation and piping component, transportation velocity, and material properties of porous media during the sampling and transportation process. The results of this study should be useful for understanding flow characteristics of the sampling and transportation system and its design and application.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.51-52
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• 2018

화력발전용 순환유동층 보일러는 환경오염의 주요인인 질소산화물(NOx)과 황산화물(SOx)의 배출량이 적은 친환경 화력발전용 보일러로 화력발전 업계에서 각광받고 있는 추세이다. 그러나 순환유동층 보일러의 연료인 유동매체는 미분탄과 같이 작지만 단단한 고체이므로 유동매체의 타격으로 인해 워터월(waterwall) 튜브의 마모는 물론 누설까지 야기할 수 있다. 순환유동층 보일러 튜브에서 누설된 증기는 보일러 내부에 클링커(Clinker)를 발생시키고 이는 순환유동층 보일러 튜브 표면에 응고되어 열전도율을 감소시킬 뿐만 아니라 보일러 운전정지의 원인이 된다. 따라서 본 논문에서는 음향방출 센서를 이용하여 화력발전용 순환유동층 보일러 튜브의 누설 위치를 추정하는 방법을 제안한다. 제안 방법에서는 매질의 분자단위 이동에 의해 발생되는 탄성파를 감지할 수 있는 음향방출 센서를 이용하고, 보일러 워터월 튜브의 멤브레인 용접부와 비용접부(seamless)의 감쇠율을 고려한 위치별 센서 감도 추정 알고리즘을 통해 워터월 튜브의 위치별 진폭 크기를 히트맵으로 표현할 수 있다.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.2
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• pp.110-115
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• 2010

This study was conducted to estimate the feasibility using thermal image measurement that is applicable to internal leak diagnosis for the power plant valve. Abnormal heating of valve surface associated with high temperature steam f10w toward valve outlet side in the condition of low temperature is a primary indicator of leakage problems in high temperature and pressure valves. Thermal imaging enables to see the invisible thermal radiation that may portend impending damage before their condition becomes critical. When steam flow in valve outlet side in the condition of low temperature is converted into heat transmitted through the valve body due to the internal leakage in valve. The existence of abnormally increasable leakage rate in the valve will result in abnormally high levels of heat to be generated that can be quickly identified with a thermal image avoiding energy loss or damage of valve component. From the experimental results, it was suggested that the thermal image measurement could be an effective way to precisely diagnose and evaluate internal leak situation of valve.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.10a
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• pp.465-466
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• 2012

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.9
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• pp.828-833
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• 2010

Steam leakage is one of the major issues for the structural fracture of pipes of nuclear power plants. Therefore a method to inspect a large area of piping systems quickly and accurately is needed. In this paper, we proposed the method for the detecting steam leakage by using image signal processing. Our basic idea come from heat shimmer which shine with a soft light that looks as if it shakes slightly. To test the performance of this technique, experiments have been performed for simple heat source and steam generator. Results show that the proposed technique is quite powerful in the steam leak detection.