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음향방출기술을 이용한 원자력발전소 제어밸브 유체누설 상시감시에 관한 연구
이상국(Sang-Guk Lee),박종혁(Jong-Huck Park),이선기(Sun-Ki Lee),유근배(Keun-Bae Yoo),홍승열(Sung-Yull Hong) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
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 for high pressure turbine condensing water dump and main steam condensing water control on the normal size of 1-1/2, 2-1/2 and 2 . 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.
이상국(Sang-Guk Lee),박종혁(Jong-Huck Park),이선기(Sun-Ki Lee),유근배(Keun-Bae Yoo),홍승열(Sung-Yull Hong) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
To verify the system performance of portable AE leak diagnosis system which can measure with moving conditions, AE activities such as RMS voltage level, AE signal trend, leak rate degree according to AE database, FFT spectrum were measured during operation on total 11 valves of the secondary system in nuclear power plant. AE activities were recorded and analyzed from various operating conditions including different temperature, type of valve, pressure difference, valve size and fluid. The results of this field study are utilized to select the type of sensors, the frequency band for filtering and thereby to improve the signal-to-noise ratio for diagnosis for diagnosis or monitoring of valves in operation. As the final result of application study above, portable type leak diagnosis system by AE was developed. The outcome of the study can be definitely applied as a means of the diagnosis or monitoring system for energy saving and prevention of accident for power plant valve.
정일석(Ill-Seok Jeong),김상재(Sang-Jai),홍승열(Sung-Yull Hong) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.8
Among published environmental fatigue test data of stainless steels, Type 304 SS, Type 316 SS, Type 316N SS, Type 316 Weld SS, and cast stainless steel CF8M in Japan and U.S., useful data were quoted for analyzing the effect of sensitizing stainless steels in LWR environments. Temperature of the test data are 288~325℃ which is operating temperature range of LWR plants. Data were classified in terms of dissolved oxygen levels, strain rates in tension stroke, and sensitization. Then data were compared with logarithmic graph of vertical strain rate and horizontal fatigue life. Trend of sensitization was investigated for each type of stainless steels.
모터구동 게이트밸브 열림행정시 차압 작용에 의한 부하율 연구
김대웅(Dae Woong Kim),박성근(Sung Keun Park),정래혁(Rae Hyuck Jeoung),이도환(Do Hwan Lee),홍승열(Sung Yull Hong) 한국유체기계학회 2004 유체기계 연구개발 발표회 논문집 Vol.- No.-
The Rate-of-Loading(ROL) effect of motor operated gate valves causes a decrease in the thrust delivered at a specific torque by the actuator under dynamic flow △P conditions as compared to the no-flow, static conditions. This effect needs to be studied for the quantitative evaluation of motor operated gate valve operability. This study is performed to verify the validity for the application of ROL in the evaluation of operability of motor operated gate valves for the opening stroke. The ROL is assessed on the basis of in-situ test data for the opening and closing strokes. The results show that the distribution of the ROL for the opening stroke has a tendency to the negative value when DP is higher than 150psid.
정일석(Ill-Seok Jeong),김상재(Sang-Jai Kim),홍승열(Sung-Yull Hong) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
Among published environmental fatigue test data of stainless steels, Type 304 SS, Type 316 SS, Type 316N SS, Type 316 Weld SS, and cast stainless steel CF8M in Japan and U.S., useful data were quoted for analyzing the effect of sensitizing stainless steels in LWR environments. Temperature of the test data are 288~325℃ which is operating temperature range of LWR plants. Data were classified in terms of dissolved oxygen levels, strain rates in tension stroke, and sensitization. Then data were compared with logarithmic graph of vertical strain rate and horizontal fatigue life. Trend of sensitization was investigated for each type of stainless steels.
송석윤(Seok-Yoon Song),김양석(Yang-seok Kim),박성근(Sung-keun Park),홍승열(Sung-Yull Hong) 한국유체기계학회 2003 유체기계 연구개발 발표회 논문집 Vol.- No.-
The experimental apparatus is designed and installed to measure the disc positions with flow velocity, Vopen and Vmin for 3 inch and 6 inch swing check valves. The minimum flow velocity necessary to just open the disc at a full open position is referred to as Vopen, and Vmin is defined as the minimum velocity to fully open the disc and hold it without motion. In the experiments, Vmin is determined as the minimum flow velocity at which the back stop load begins to increase after the disc is fully opened or the oscillation level of disc is reduced below 1°. The results show that the Vmin velocities for 3 inch and 6 inch swing check valves are about 15.6% and 4.8% higher than the Vopen velocities, respectively. Although the experiments were done with the stable uniform flow, additional experiments will be performed to determine the effects of the upstream disturbances.