• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.333-337
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• 2004

Steam Generator is one of the most important structural part of nuclear power plant. It is manufactured by various steel forgings such as shell, head, torus and tubesheet. These steel forgings have been made by open die forging process. After steel melting and ingot making, open die forging has been carried out to get a good quality which means high soundness and homogeniety of the steel forgings by using high capacity hydraulic press. This paper introduced the open die forging process and manufacturing experience of large tubesheet forgings which will be used for the steam generator of 1,400MW nuclear power plant.

• 동력기계공학회지
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• 제11권1호
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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.

• KEPCO Journal on Electric Power and Energy
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• 제5권4호
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• pp.323-330
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• 2019

500 MW 표준 석탄화력발전소는 국내에서 가장 큰 용량의 규격화된 발전소로써 20년 넘게 국내 전력생산에 중추적인 역할을 수행하고 있다. 장기간 사용으로 인한 경년 열화와 더불어 최근 석탄화력발전소의 대기오염 문제가 대두되면서 석탄화력발전소 가동률 제한 정책에 따른 잦은 기동·정지에 의해 발전 설비의 고장 확률이 증가하고 있다. 그 중 증기 배관은 보일러에서 만들어진 고온·고압의 증기를 전력생산을 위해 터빈으로 이송시키는 중요한 역할을 하는 설비로 최근 국내 대용량 발전소 증기 배관의 고장 사례가 빈번하게 발생하고 있다. 이에 본 연구에서는 국내 500 MW 표준 석탄화력발전소 주증기배관 연결 용접부에 반복적으로 발생된 손상에 대해 손상 해석을 수행하였다. 동일 규격의 타 발전소에서 발생될 수 있는 고장의 사전 예방을 위해 균열부 금속 조직 분석과 배관 응력 해석을 통해 배관 지지 구조에 의한 고 응력에 의해 발생된 원인을 규명하고 고 응력부 응력 저감을 위한 지지 구조 개선 방안을 제시하였다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.73-79
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• 2003

The steam turbine efficiency is an important factor in power plant. Accurate evaluation of steam turbine performance is essential. However, it is not easy to evaluate the steam turbine performance due to its high temperature and high pressure circumstance. Therefore most steam turbine performance tests were conducted by air similarity test. This paper described a test program for air similarity test of steam turbine at Korea Aerospace Research Institute. A test facility has been designed and built to evaluate aerodynamic performance of turbines. The test facility consists of air supply system, single stage test section, power absorption system, instrumentation and auxiliary system. For evaluation of steam turbine performance, the test of single stage axial turbine air similarity performance was conducted and uncertainty analysis was performed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.691-692
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• 2009

• 시스템엔지니어링학술지
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• 제11권1호
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• pp.81-93
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• 2015

Steam Reforming H2 Generation (SRH2G) System is a chemical process to produce hydrogen through steam reforming of hydrocarbon. Largely speaking, there are two types of materials for the SRH2G: 1) Oil and coal, and 2)Natural Gas such as shale gas. From the perspective of cost, quality (purity), and environmental burden (pollution), the latter is much more desirable than the former. For this reason, research on SRH2G using natural gas is actively carried out, and implemented and operated in the various industry. In this paper, we develop a natural gas based SRH2G system via systems engineering approach. Specifically, we first derived stakeholder requirements, followed by systems requirements and finally system architecture via a tailored SE process for plant (called Plant Systems Engineering (PSE) process) based on ISO/IEC 15288. The developed method was applied to iron and steel plant as a case study. Through the case study, by the SE approach, we were convinced that a successful system satisfying stakeholders' requirements within the given constraints can be developed, verified and validated.

• 한국지능시스템학회논문지
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• 제8권6호
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• pp.1-11
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• 1998

본 논문에서는 원자력 발전소 증기발생기를 위한 논리 프로세서에 기초한 모델링 방법에 대하여 다룬다. 증기발생기의 모델링은 여러 가지 요소들 중 특히, 열역학성 특성에 기인한 수축(shrink)과 팽창(swell)의 현상을 가지는 비최소위상 특성에 의해 수학적 모델링에 어려움이 있다고 알려져 있다. 이러한 어려움을 극복하기 위해서 본 논문에서는 기존의 신경회로망과는 달리 전문가의 지식을 포함할 수 있으면서 효율적인 학습이 가능한 구조를 가진 논리프로세서(logic processor)를 이용하여 증기발생기 모델링을 행하였으며, 다양한 시뮬레이션을 통하여 제안된 방법의 유용함을 보였다.

• 한국소음진동공학회논문집
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• 제15권8호
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• pp.988-995
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• 2005

Vibration has been severly increased at the branch pipe of main steam header since the commercial operation of nuclear power plant. Intense broad band disturbance flow at the discontinuous region such as elbow, valve, and header generates the acoustical pulsation which is propagated through the piping system. The pulsation becomes the source of low frequency vibration at piping system. If it coincide with natural frequency of the pipe system, excessive vibration is made. High level vibration due to the pressure pulsation related to high dynamic stress, and ultimately, to failure probability affects fatally the reliability and confidence of plant piping system. This paper discusses vibration effect for the branch pipe system due to acoustical pulsations by broad band disturbance flow at the large main steam header in 700 MW nuclear power plant. The exciting sources and response of the piping system are investigated by using on-site measurements and analytical approaches. It is identified that excessive vibration is caused by acoustical pulsations of 1.3 Hz, 4.4 Hz and 6.6 Hz transmitted from main steam balance header, which are coincided with fundamental natural frequencies of the piping structure. The energy absorbing restraints with additional stiffness and damping factor were installed to reduce excessive vibration.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.780-785
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• 2005

Vibration has been severly increased at the branch pipe of main steam header since the commercial operation of a nuclear power plant. Intense broad band disturbance flow at the discontinuous region such as elbow, valve or heather generates the acoustical pulsation which is propagated through the piping system. The pulsation becomes the source of low frequency vibration at piping system. If it coincide with natural frequency of the pipe system, excessive vibration is made. High level vibration due to the pressure pulsation related to high dynamic stress, and ultimately, to failure probability affects fatally the reliability and confidence of plant piping system. This paper discusses vibration effect for the branch pipe system due to acoustical pulsations by broad band disturbance flow at the large main steam header in 7nn nuclear power plant. The exciting sources and response or the piping system are investigated by using on site measurements and analytical approaches. It is identified that excessive vibration is caused by acoustical pulsations of 1.3Hz, 4.4Hz and 6.6Hz transferred from main steam header, which are coincided with fundamental natural frequencies of the piping structure. The energy absorbing restraints with additional stiffness were installed to reduce excessive vibration.

• 에너지공학
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• 제6권2호
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• pp.170-175
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• 1997

본 연구에서는 원자력발전소 내 증기발생기의 원만한 수위제어 향상을 위하여 고리 원자력발전소 모델을 기준으로 Full Linear Scale Down 1/10 크기의 증기발생기 Mock-up을 제작하여 증기 덤프 밸브 개폐시 수위의 수축(shrink), 팽창(swell) 현상을 확인해 보고, 그 원인을 규명하여 보았다. 이와 함께 본 연구를 위하여 개발한 Fuzzy제어기를 이 Mock-up의 제어기로 운용해 봄으로써 제작된 Mock-up이 실제 원자력 발전소 증기발생기의 경우와 같이 수위제어가 가능함을 확인하였고 이에 따라 향후 개발되어질 수 있는 제반 제어기들을 본 Mock-up에 도입, 운용해 봄으로써 제작한 Mock-up의 Simulator로서의 활용 가능성을 실험적으로 검증할 수 있도록 하였다.