• Title/Summary/Keyword: Pipe rupture

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Comparison Between FAC Analysis Result Using ToSPACE Program and Experimental Result (ToSPACE 프로그램을 이용한 FAC 해석결과와 실험결과 비교)

  • Hwang, Kyeongmo;Yun, Hun;Seo, Hyukki;Jung, Euije;Kim, Kyungmo;Kim, Dongjin
    • Corrosion Science and Technology
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    • v.19 no.3
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    • pp.131-137
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    • 2020
  • A number of piping components in the secondary system of nuclear power plants (NPPs) are exposed to aging mechanisms, such as flow-accelerated corrosion (FAC), cavitation, flashing, solid particle erosion, and liquid droplet impingement erosion. Those mechanisms may lead to thinning, leaking, or rupture of the components. Due to the pipe ruptures caused by wall thinning in Surry unit 2 in the USA in 1986 and Mihama unit 3 in Japan in 1994, pipe wall thinning management has emerged as one of the most important issues in the nuclear industry. To manage pipe wall thinning, a foreign program has been utilized for NPPs in Korea since 1996. As our experience and knowledge of pipe wall thinning management have accumulated, our program needs to reflect our experience, requests from users, and the result of recent experiments using Flow Accelerated Corrosion Testing System (FACTS). FACTS is the empirical experimental facility developed by Korea Atomic Energy Research Institute (KAERI) for tests. Accordingly, KEPCO-E&C developed a 3D-based pipe wall thinning management program called ToSPACE in 2016. This paper describes a comparison between the FAC analysis results using ToSPACE and the experimental results using FACTS to verify their applicability to pipe wall thinning management in NPPs.

A Study for Comparison of Consequence Analysis for Buried Pipeline Considering the Depth Factor (깊이 인자를 고려한 매설배관의 사고피해영향 비교 분석에 관한 연구)

  • Han, Seung-Hoon;Seol, Ji-Woo;Yoo, Byong-Tae;Tae, Chan-Ho;Ko, Jae Wook
    • Journal of the Korean Institute of Gas
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    • v.20 no.5
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    • pp.9-16
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    • 2016
  • Buried pipe system is subject to leak or rupture due to internal and external defects with age. Especially, if the pipeline is designed for pressurized gas, the leak can wreak a devastating on its surrounding area. The current method of setting up underground gas pipeline is based on OGP criteria of applying one tenth of the inner pipe pressure. The criteria is applied irrespective of their burial depth or pipe's properties. At times, even the whole safety measures are totally ignored. Considering the magnitude of possible damage from a gas leakage, a precise analytical tool for the risk assessment is urgently needed. The study was conducted to assess possible scenarios of gas accidents and to develop a computer model to minimize the damage. The data from ETA was analyzed intensively, and the model was developed. The model is capable of predicting jet fire influence area with comprehensive input parameters, such as burial depth. The model was calibrated and verified by the historic accident data from Edison Township, New Jersey, the United States. The statistical model was also developed to compare the results of the model in this study and the existing OGP model. They were in good agreement with respect to damage predictions, such as radiation heat coming from 10 meters away from the heat source of gas flame.

Round Robin Test for Reliability Evaluation of Ultrasonic Thickness Measurement Results in Nuclear Power Plant Pipelines (원전감육배관 UT 두께측정 결과의 신뢰도 평가를 위한 다자비교시험)

  • Lee, Seung-Joon;Yi, Won-Geun;Lee, Joon-Hyun;Lee, Sung-Ho
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1702-1707
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    • 2007
  • The reduction of pipe-thickness induced by flow accelerated corrosion (FAC) is one of the most serious problems on the maintenance of piping system in nuclear power plants (NNP). If the thickness of a pipe component is reduced below the critical level, it cannot sustain pressure and consequently results in leakage or rupture. For this reason, wall thinning by FAC has been inspected in secondary side piping systems in NPPs. In this research Round Robin Test (RRT) was conducted to verify confidence of wall thinning measurement system in NPP. 12 inspectors from 3 companies participated and 23 specimens were used according to standard practice in RRT. The gage R&R analysis was introduced in regard to repeatability and reproducibility that are affected to measurement system errors. Confidence intervals of thickness measurement system were obtained.

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Examination and Measures on Failure of Hydraulic Oil Supply Pipe of Control Valve of Steam Turbine in 200MW Thermal Power Plant (200MW급 화력발전소 고압터빈 제어밸브 압유배관의 절손 원인과 대책)

  • Kim, Yeon-Whan;Lee, Young-Shin;Kim, Hee-Soo;Lee, Hyun;Kim, Sung-Hwi
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.569-576
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    • 2002
  • A case history is presented pertaining to piping fatigue by vibrations and sustain stresses in the hydraulic oil supply system for control valves in a 200MW thermal power plant that ultimately resulted in pipe rupture. The Piping was designed to supply the hydraulic oil for turbine control valves. Testing and analyses were performed on the system to develop solution to repair work on failures.

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Self-Ignition of Hydrogen in a Pipe by Rupture of Pressure Boundaries (파열 압력경계 조건에 따른 파이프 내에서의 수소 자발 점화)

  • Lee, Hyoung Jin;Kim, Sung Don;Kim, Sei Hwan;Jeung, In-Seuck
    • 한국연소학회:학술대회논문집
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    • 2013.06a
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    • pp.95-96
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    • 2013
  • Numerical simulations are conducted to investigate the mechanism of spontaneous ignition of hydrogen within a certain length of downstream pipe released by the failure of pressure boundaries of various geometric assumption. The results show that local ignition is developed in limited area such as boundary layer and the mixing of hydrogen and air is weak at the planar pressure boundary conditions, whereas the flame fronts at the contact region are developed at the pressure boundaries of the spherical shape.

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Risk Assessment and Safety Measures for Methanol Separation Process in BPA Plant (BPA 공장의 메탄올 분리공정에서 위험성 평가 및 안전대책)

  • Woo, In-Sung;Lee, Joong-Hee;Lee, In-Bok;Chon, Young-Woo;Park, Hee-Chul;Hwang, Seong-Min;Kim, Tae-Ok
    • Journal of the Korean Institute of Gas
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    • v.16 no.3
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    • pp.22-28
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    • 2012
  • For a methanol separation column of the BPA (Bisphenol A) plant, HAZOP (hazard and operability) assessment was performed and damage ranges were predicted from the accident scenarios for the fire and the explosion. As a result, the damage range of the jet fire was 20 m in the case of rupture of the discharge pipe (50 mm diameter) of safety valve, and that of the flash fire was 267 m in the case of catastrophic rupture. Also, the damage ranges of the unconfined vapor cloud explosion (UVCE) for the rupture of the discharge pipe and for the catastrophic rupture were 22 m and 542 m, respectively. For the worst case of release scenarios, safety measures were suggested as follows: the pressure instruments, which can detect abnormal rise of the internal pressure in the methanol separation column, should be installed by the 2 out of 3 voting method in the top section of the column. Through the detection, the instruments should simultaneously shut down the control and the emergency shut-off valves.

Uncertainty Analysis of Containment Leak Rate Test System (격납건물 누설 시험장치의 불확실도 평가)

  • Lee, Kwang-Dae;Yang, Seung-Ok;Oh, Eung-Se
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.635-637
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    • 2004
  • The containment of the nuclear power plant is the last barrier of radiation release when the reactor coolant pipe rupture is occurred. Each plant has to be tested every 5 years whether the containment leak rate meets its technical specifications. We have developed the leak rate test system and in this paper, we describe the results of the uncertainty analysis on the measurement channels and its propagation to the calculation results.

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The creep rupture properties on welded joints of Cr-W pipe steels for boiler in advanced thermal power plant (석탄화력발전소 보일러 배관용 Cr-W계 강 용접부의 크리프 파단특성)

  • 이연수;유석현;공병욱;이경운;김정태
    • Proceedings of the KWS Conference
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    • 2004.05a
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    • pp.149-151
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    • 2004
  • 고효율, 대용량의 친환경적이며 경제적인 발전소건설을 위해 초초임계압(USC: Ultra Super Critical) 석탄화력발전소의 건설이 세계적인 추세이다. 이러한 USC발전소는 효율향상을 위해 증기온도와 압력의 상승, 경제적 운용을 위해 부하변동운전 적용확대가 필수적이다. (중략)

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A Study on the Reinforcement of the Soil Blocking Facilities Due to Water Pipe Rupture Accident (상수관 파열 사고로 인한 흙막이 가시설 보강사례 연구)

  • Woo, Jong-Tae
    • Proceedings of the Korean Society of Disaster Information Conference
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    • 2023.11a
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    • pp.241-243
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    • 2023
  • 아파트 신축공사 흙막이 가시설 현장에 근접 매설된 상수관의 누수 및 파열 사고로 터파기 공사 현장에 토사 유실 및 지반 함몰이 발생되었으며, 흙막이 가시설의 토류판이 파손되었다. 흙막이 가시설의 안정성 확보를 위해 벽체구간은 레이커로 보강하고 사보강재는 1단과 2단을 묶어 힘을 분산시키고 종방향으로 보강 및 토류판 보강을 시행하였다.

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A Study on the Monitoring Case of the Soil Blocking Facilities Due to Water Pipe Rupture Accident (상수관 파열 사고로 인한 흙막이 가시설 계측사례 연구)

  • Woo, Jong-Tae
    • Proceedings of the Korean Society of Disaster Information Conference
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    • 2023.11a
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    • pp.244-246
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    • 2023
  • 아파트 신축공사 흙막이 가시설 현장에 근접 매설된 상수관의 누수 및 파열 사고로 인접 건물이 공사현장 방향으로 58~188mm 기울어졌으며, 지중수평경사계 계측결과 21.07.20일 22.64mm가 21.10.18.일 101.46mm로 급격하게 78.82mm의 큰 수평 변위가 발생되었으며, 이로 인해 흙막이 가시설의 사보강재가 변형되고 토류판 일부가 파손되었다.

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