• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1830-1837
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• 2023

The thermal cutting of contaminated or activated metals during decommissioning nuclear power plants inevitably results in the release of radioactive aerosol. Since radioactive aerosols are pernicious particles that contribute to the internal dose of workers, air conditioning units with a HEPA filter are used to remove radioactive aerosols. However, a HEPA filter cannot be used permanently. This study evaluates the efficiency and lifetime of filters in actual metal cutting condition using a plasma arc cutter and a high-resolution aerosol detector. The number concentration and size distribution of aerosols from 6 nm to 10 ㎛ were measured on both the upstream and downstream sides of the filter. The total aerosol removal efficiency of HEPA filter satisfies the standard of removing at least 99.97% of 0.3 ㎛ airborne particles, even if the pressure drop increases due to dust feeding load. The pressure drop and particle size removal efficiency at 0.3 ㎛ of the HEPA filter were found to increase with repeated cutting experiments. By contrast, the efficiency of used HEPA filter reduced in removing nano-sized aerosols by up to 79.26%. Altogether, these results can be used to determine the performance guidance and replacement frequency of HEPA filters used in nuclear power plants.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.341-344
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• 2007

교토의정서(Kyoto Protocol)는 1997년 일본 교토에서 채택되어 2005년 2월에 공식 발효되었다. 우리나라는 현재 온실가스 감축의무 부담이 없지만 2013년부터 감축의무가 거의 확실시되고 있는 상황이다 국내 온실가스 배출량의 25%를 차지하는 발전산업은 화석연료를 사용하고 있어 전력생산에 따른 $CO_2$ 배출량의 계산은 매우 중요한 일이 되었다. 본 논문은 - D발전소의 성능시험에 대하여 기술하고, - 성능시험 결과 얻어진 D발전소 성능시험 Data a, b, c 특성계수를 이용, LNG와 중유 연소시 각각 연료소모량에 대한 $CO_2$ 대기 배출량을 계산 비교하였으며, - 화학적인 방법에 의한 $CO_2$ 대기 배출량 산정방법을 간략히 언급하였다.

• 한국압력기기공학회 논문집
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• 제6권2호
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• pp.20-27
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• 2010

In order to prevent the corrosion of component contacted primary water designed alloy 600 material in the nuclear power plant. But the primary water stress corrosion cracking(PWSCC) of alloy 600 and weld area occurs continuously due to the residual stress. The leakage accident resulted from PWSCC in the drain nozzle of the steam generator of domestic power plants. Heater sleeves of the pressurizer are welded with alloy 600 weld material and therefore exposed to the primary water environment. PWSCC occurred in heater sleeve material and weld area of many foreign power plants. The current issue of domestic nuclear power plants are consequently concentrated to PWSCC of similar material. In order to improve the detection and the sizing of the PWSCC in the welding sleeve of the pressurizer, the automatic UT system and multi-directions probe sets have been developed. The experimental studies have been performed using the mock-up block containing artificial reflectors(ID connected EDM notch) and semi-artificial cracks made from thermal fatigue. The automatic UT System is applied in the detection and the length sizing of the ID/OD on the tube and the J-groove weld area of the artificial reflectors and results of the detection and the sizing are compared respectively. Also, the developed automatic UT system is successfully accomplished to inspect the heater sleeve and the J-groove weld area on the pressurizer for the detection of PWSCC.

• 대한기계학회논문집B
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• 제40권6호
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• pp.397-402
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• 2016

원자력 발전소와 화력 발전소에서는 양질의 전기를 생산하기 위해서는 발전기에 연결된 고압 및 저압 증기터빈에 최적량의 증기를 공급하여야 한다. 터빈에 증기를 공급하거나 차단하는 특수한 밸브인 터빈출력제어장치를 사용하고 있으며, 이 터빈출력제어장치는 유압서보 액추에이터로 구동 된다. 발전소에서는 유압시스템에서 생성되는 기체로 인하여 유압서보 액추에이터의 성능이 저하되거나, 생성된 기체가 압축되면서 발생하는 열로서 씰을 태우고 마모를 증가시켜서 빈번한 고장이 유발된다. 일부 발전소에서는 고정형 오리피스를 사용하여 공기를 배출하고 있지만 많은 유량배출에 따른 동력 손실과 빈번하게 작동되는 펌프, 전기모터 및 밸브 등의 고장을 발생시킨다. 본 연구에서는 기존의 고정형 오리피스와 같이 초기에 많은 량의 공기를 배출하고 정상운전에서는 매우 미세한 유량만 통과 시킬 수 있는 부하 감응형 공기 배출밸브를 모델링하고 해석하여 장착함으로서 유압서보 액추에이터의 제어 정밀성 확보와 기체 압축으로 인한 고장을 방지할 수 있게 하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.744-748
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• 1989

A newly developed Expert System (ES) for the tuning of thermal power plant control equipment is described. The system is furnished with the rules for controller tuning which were obtained by analysis and arranging the data and knowledge from the experts or tuning records. Based on these rules, automatic tuning or setting of the control parameters is performed in real-time base. The performance of the test equipment, a combination of ES and a boiler simulator, was examined in the automatic tuning test for steam pressure, steam temperature, and load controllers of a constant-pressure once-through boiler model. It was confirmed from the test results that the system is quite promising for future application to actual plants, since the tuning results obtained by the proposed system were similar to those by tuning experts.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1823-1828
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• 2000

Power transformers, air-intakes, stacks in a combined thermal power plant are the main noise sources. Power transformer noise among them has being get a target of public complaint due to 480Hz component of its pure tone. The source is mainly magnetostrictive vibration of the transformer core. The first countermeasures was installing sound barrier on the front of transformer. However, 500Hz, center of the frequency is not reduced. This paper includes the measurements of noise level at the near resident apartment, the identification of noise transfer and the countermeasures for noise sources. Cavity resonance type of noise reduction devices was installed on enclosuring wall of transformers. As a result, the noise level from transformer is reduced about 3dB.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.614-616
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• 1998

Control systems used in power plants consist of some control modules which are operated independently. A failure of control system mainly depends on a failure of control modules. So, it is important to estimate lifetimes of control modules in order to assess the reliability of control systems. In this paper, three methods for estimating lifetimes of control modules are presented and control modules' lifetimes of boiler control system used in a thermal power plant are estimated applying the three methods. Also, advantage and disadvantage of three methods are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2342-2344
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• 2000

Many years ago, most of thermal power plants built in this country were of subcritical pressure, of medium or small size, of constant pressure operation, of drum type steam generator. But, nowadays, almost all of them were of high efficiency, of supercritical pressure, of great capacity(about 500MW), of sliding pressure operation, of once through type steam generator. Presently built once through boiler introduces turbine bypass systems to variable pressure operation which eliminates unexpected materials in boiler tube during startup, minimizes fuel loss by short startup period, eventually improves total efficiency and power system stability

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 추계학술대회
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• pp.572-573
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• 2021

지능형 경로 이동 기능을 갖춘 드론을 이용하여, IoT형 열화상 기반 태양광 고장 검출 장비의 개발 및 드론과의 연동을 최적화하여 취득된 이미지 데이터의 실시간 분석을 통해 태양광 발전소의 고장 판독을 용이하게 함으로써, 태양광발전소의 발전율 향상과 효율적인 유지관리 모델을 만들 수 있는 기반 기술의 제시와 이미지 차감 분석기법을 이용하여 태양광 패널의 고장을 판독할 수 있는 시스템을 설계한다.

• 한국안전학회지
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• 제32권3호
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• pp.34-40
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• 2017

The catastrophic collapse of the in-boiler scaffolding system in the two thermal power plants occurred in March and April 2012. After site investigation and document review, it was found that the specialized scaffolding system was imported for overhaul & maintenance and that the system did not get the safety certification at the import. In this regard, this study developed & proposed an access platform and a support for the vertical tube section of the super heat as well as a variable-length platform for the horizontal tube section, satisfying the domestic certification standards. The access platform was developed to be easy to handle by the worker with a weight of about 0.069 kN, which could reduce the risk of falling accidents and workers' musculoskeletal diseases. For the variable-length platform, it is possible to cope with various changes in length between the horizontal tubes associated with the increase of rigidity in the overlapping and the elimination of the protrusion.