• Nuclear Engineering and Technology
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• 제47권2호
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• pp.148-156
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• 2015

Several vendors have recently been actively pursuing the development of integral pressurized water reactors (iPWRs) that range in power levels from small to large reactors. Integral reactors have the features of minimum vessel penetrations, passive heat removal after reactor shutdown, and modular construction that allow fast plant integration and a secure fuel cycle. The features of an integral reactor limit the options for placing control and safety system instruments. The development of instrumentation and control (I&C) strategies for a large 1,000 MWe iPWR is described. Reactor system modeling-which includes reactor core dynamics, primary heat exchanger, and the steam flashing drum-is an important part of I&C development and validation, and thereby consolidates the overall implementation for a large iPWR. The results of simulation models, control development, and instrumentation features illustrate the systematic approach that is applicable to integral light water reactors.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.77-81
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• 2002

In many high performance engineering systems such as automated production system and transportation systems, AC-servo drives are employed as the most Important driving parts. And the faults of servo drives result in overall system performance deterioration or an unscheduled shutdown In critical situations. The real-time fault detection and isolation(FDI) scheme Is very useful to prevent them and to guarantee the desired reliability of the overall system. In this paper, the FDI schemes which can be applied to AC servo drives are introduced and some new results are presented.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제2권3호
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• pp.191-193
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• 2002

Insulation aging diagnosis system provides early warning in regard to electrical equipment defects. Early warning is very important in that it can avoid great losses resulting from unexpected shutdown of the production line. For solving this problem, many researchers proposed a method that diagnose power plant by using partial discharge. In this paper, we design the intelligent sensor to diagnose insulation degradation state that uses a Microprocessor and Al. Proposed sensor has MCU that is used to diagnose insulation degradation and communicate with main IDD system. And we use a fuzzy model to diagnose insulation degradation.

• Nuclear Engineering and Technology
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• 제30권4호
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• pp.377-385
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• 1998

Many nuclear power plants have experienced unscheduled shutdown due to the leakage of steam generator tubes. The leakages are normally due to the crack, possibly stress corrosion cracking (SCC) near the tube expansion at the top of tubesheet or at the tangential point of the row-1 U-bend region. The conventional eddy current technique, which makes use of a differential bobbin coil, has been found to be inadequate for the early detection of SCC. During the in-service inspection, therefore, it is a general practice that the rotating pancake coil (RPC) is used for detecting the cracks. Even in using RPC, however, it is difficult to determine the depth of the cracks quantitatively. This paper attempts to determine the detectability and sizing ability of RPC technique for axial or circumferential cracks at the tube expansion region. The simulated cracks with various dimensions were fabricated by electro-discharge machining (EDM) method. Experimental results are discussed with theoretical calculations.

• 한국압력기기공학회 논문집
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• 제7권3호
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• pp.30-39
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• 2011

URANUS (Ubiquitous, Robust, Accident-forgiving, Non-proliferating, Ultra-lasting and Sustainer) has been developed with 35MWe (100MWth) operating without primary coolant pump, capitalizing on natural circulation capability of lead-bismuth eutectic (LBE) for long-life small and robust power units. To ensure the structural integrity, the large safety margin against Safe Shutdown Earthquake, 0.3g, and furthermore the cost effectiveness for URANUS, three-dimensional seismic base isolation design has been developed. The analytical model has been developed and seismic time history analyses have been carried out. The advantage for using three-dimensional seismic base isolation for URANUS has been discussed.

• Nuclear Engineering and Technology
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• 제48권2호
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• pp.470-481
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• 2016

Field-programmable gate arrays (FPGAs) have received much attention from the nuclear industry as an alternative platform to programmable logic controllers for digital instrumentation and control. The software aspect of FPGA development consists of several steps of synthesis and refinement, and also requires verification activities, such as simulations that are performed individually at each step. This study proposed an integrated software-testing framework for simulating all artifacts of the FPGA software development simultaneously and evaluating whether all artifacts work correctly using common oracle programs. This method also generates a massive number of meaningful simulation scenarios that reflect reactor shutdown logics. The experiment, which was performed on two FPGA software implementations, showed that it can dramatically save both time and costs.

• 한국소음진동공학회논문집
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• 제22권10호
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• pp.932-939
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• 2012

Recently, data centers are being established because IT and telecommunication industries are growing. The data centers have to install emergency generators to prevent unexpected shutdown of the electrical power supply. When the data centers are located in the densely populated urban area, the operating noise of the emergency generators can be a cause of people's complaints. In this case, it is necessary to establish effective countermeasure by noise & vibration specialists. To achieve this, noise reduction measure using noise measurement data and 3D noise analysis method have been employed in this study.

• Nuclear Engineering and Technology
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• 제34권4호
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• pp.331-343
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• 2002

We performed an importance analysis of In-Service Testing (157) components for Ulchin Unit 3 using the integrated evaluation method for categorizing component safety significance developed in this study. The developed method is basically aimed at having a PSA expert perform an importance analysis using PSA and its related information. The importance analysis using the developed method is initiated by ranking the component importance using quantitative PSA information. The importance analysis of the IST components not modeled in the PSA is performed through the engineering judgment, based on the expertise of PSA, and the quantitative and qualitative information for the 157 components. The PSA scope for importance analysis includes not only Level 1 and 2 internal PSA but also Level 1 external and shutdown/low power operation PSA. The importance analysis results of valves show that 167 (26.55%) of the 629 IST valves are HSSCs and 462 (73.45%) are LSSCs. Those of pumps also show that 28 (70%)of the 40157 pumps are HSSCs and 12 (30%) are LSSCs.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(2)
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• pp.477-482
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• 1997

Safe shutdown earthquakes (SSE) of four existing nuclear power plant sites were evaluated by using a probabilistic method. It turned out that the SSE's of the two sites are smaller than those of the rest. Site-specific response spectra were developed for two sites of which SSE's show a comparatively large difference. The result shows that the site-specific response spectrum of one site is higher by a factor of 1.5 than that of the other. The comparison of uniform hazard spectrum and site-specific response spectrum at one of the two sites shows that the both spectra are consistent with each other.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2011년도 추계학술발표대회
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• pp.546-548
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• 2011

컴퓨터 실습실에서 사용되고 있는 씬 클라이언트 PC는 개인별로 할당된 것이 아니라 다수의 사용자들이 공유하기 때문에 씬 클라이언트 PC를 관리하기 위한 별도의 관리시스템(Management System)이 필요하다. 본 논문에서는 컴퓨터 실습실 환경에서 가상머신에 원격으로 접속된 씬 클라이언트 PC의 전원관리를 효과적으로 할 수 있는 방법을 제안한다. 사용자가 이용하는 씬 클라이언트 PC에 대해 일정시간 동안 키보드/마우스의 입력이 없으면 해당 씬 클라이언트 PC로 메시지를 전송하여 사용 여부를 확인하고 해당 사용자로부터 아무런 응답이 없을 경우 씬 클라이언트 PC를 Shutdown 한다. 이러한 관리 방법은 사용되지 않는 씬 클라이언트 PC에 대해 불필요하게 낭비되는 전력을 줄일 수 있어 효율적으로 컴퓨터 실습실을 운영할 수 있을 것으로 예상된다.