• Asian Journal of Atmospheric Environment
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• 제12권3호
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• pp.255-273
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• 2018

To develop effective emission abatement strategies for eighteen coal-fired power plants located throughout Korea, power plant emission data and TAPM (The Air Pollution Model) were used to quantify the impact of emission reductions on primary $PM_{10}$ concentrations. TAPM was validated for two separate time periods: a high $PM_{10}$ concentration period from April 7 to 12, 2016, and a low $PM_{10}$ concentration period from June 1 to June 6 2016. The validated model was then used to analyze the impacts of five applicable power plant shut-down scenarios. The results showed that shut-down of four power plants located within the Seoul metropolitan area (SMA) would result in up to 18.9% reduction in maximum $PM_{10}$ concentrations, depending on synoptic conditions. A scenario for the shutdown of a single low stack height with highest-emission power plant located nearest to Seoul showed a small impact on averaged $PM_{10}$ concentrations (~1%) and 4.4% ($0.54{\mu}g/m^3$) decrease in maximum concentration. The scenario for four shutdowns for power plants aged more than 30 years within SMA also showed a highest improvement of 6.4% ($0.26{\mu}g/m^3$ in April) in averaged $PM_{10}$ concentrations, and of 18.9% ($2.33{\mu}g/m^3$ in June) in maximum concentration, showing almost linear relationship in and around SMA. Reducing gaseous air pollutant emissions was also found to be significant in controlling high $PM_{10}$ concentrations, indicating the effectiveness of coreduction of power plant emissions together with diesel vehicle emissions in the SMA. In addition, this study is implying that secondary production process generating $PM_{10}$ pollution may be a significant process throughout most regions in Korea, and therefore concurrent abatement of both gas and particle emissions will result in more pronounced improvements in air quality over the urban cities in South Korea.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 가을 학술발표논문집 Vol.32 No.2 (1)
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• pp.853-855
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• 2005

오늘날 생활환경에서 디지털 TV, 휴대용 단말기, 인터넷 셋톱박스 등 임베디드 시스템이 탑재된 정보가 전제품을 쉽게 찾아 볼 수 있다. 정보가전제품은 가전제품의 본래 기능뿐만 아니라 다른 정보가전제품과 상호 작용을 통한 인텔리전트한 기능의 수행이 요구된다. 이와 같은 인텔리전트한 기능을 수행하기 위해서는 단순한 기능만을 수행하는 펌웨어 수준의 임베디드 시스템이 아니라 다양한 기능을 수행하는 스마트 임베디드 시스템이 요구된다. 스마트 임베디드 시스템은 인텔리전트한 기능을 제공하기 위해서 네트워킹, 멀티프로세싱 등의 기능이 제공되는 범용 운영체제 수준의 성능을 가진 운영체제의 탑재가 요구된다. 그러나 이러한 범용 운영체제는 수십 초의 긴 부팅 시간을 요구함으로 이전의 파워온 (Power-On)과 동시에 사용할 수 있는 전통적인 가전제품이나 산업기계의 사용자에게는 매우 큰 불편을 초래할 수 있다. 특히 복잡한 공정을 수행하는 공장 산업기계의 임베디드 시스템은 shutdown 후 정상가동 까지 걸리는 시간이 제품 생산량 및 품질에 큰 영향을 미친다. 이와 같이 다양한 분야에서 적용된 스마트 임베디드 시스템의 부팅시간은 스마트 임베디드 시스템의 성능을 평가하는 중요한 요소가 된다. 본 논문은 임베디드 환경 하에 범용 운영체제인 리눅스를 활용하여 빠른 부팅을 구현하였다. 부팅 단계에서 영향을 미치는 부트로더, 커널 그리고 루트 파일시스템의 각 구성요소를 최적화하는 연구를 수행하였으며, 그 결과 HBE-EMPOS II 기준으로 부팅시간이 11초로 감소되는 성과를 얻었다.

• 비파괴검사학회지
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• 제23권5호
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• pp.520-525
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• 2003

Fast Breeder Test Reactor (FBTR) is a 40MW (thermal) / 13.2MW (electrical), Plutonium - Uranium mixed carbide fuelled, sodium cooled, loop type nuclear reactor operating at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam. Its main aim is to generate experience in operation of fast reactors and sodium systems and to serve as an irradiation facility for development of fuels and structural materials fur fast reactors. Nuclear reactors pose difficulties to the NDT techniques used to monitor the conditions of the internal components. Sodium cooled fast breeder reactors have their own typical difficulties in using the NDT techniques. These are due to the need for operation in aggressive environment of nuclear radiation and sodium (molten/vapour), as well as the need to maintain leak tightness of a very high order during all states of reactor operation and shutdown for fuel handling, maintenance and remote inspection. This paper discusses the following NDT techniques, which have been successfully used for the past 15 years in FBTR: (i) Periscope and Projector, (ii) Core Co-ordinate Measuring Device and, (iii) Optical fiberscope. The inspection using these techniques have given confidence for further reactor operation at high power by giving useful data on the conditions of the components inside the reactor vessel.

• 한국연소학회지
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• 제18권4호
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• pp.53-58
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• 2013

Lots of Coal power plants (about 30) using bituminous coals are being run in Korea. The use of high volatile low grade sub-bituminous coal is increasingly extended because of imbalance between the worldwide coal supply and demand. Mill-fire has been an important issue since the use of such sub-bituminous coal. In existing coal plants of Korea, shutdown of coal and air supplies could be only a way, and an alternative has not been found in suppressing the mill fire. The inside fowfield in the mills has a highly fuel-rich, low temperature, and high velocity and non-reactive such that it could be a nonreactive system essentially. Nevertheless, occasional fire-occurrence could be attributed to the existence of an ignition source. However it has not been so far investigated in detail. The current work has a focus on suppressing the mile fire via some parametric experimental study such as effects of temperature, residence time, ignition source, and inert gas mixing. The results show that an small amount of $CO_2$- or $N_2$-mixing with air is very effective in suppressing fire formation even at high temperatures or flying sparks. The results suggest that exhaust gas recirculation into the mill should be an alternative to suppress mill fire.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 추계학술발표회논문집(1)
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• pp.191-196
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• 1996

The potential value of the Application Specific Integrated Circuits(ASIC's) in safety systems of Nuclear Power Plants(NPP's) is being increasingly recognized because they are essentially hardwired circuitry on a chip, the reliability of the system can be proved more easily than that of software based systems which is difficult in point of software V&V(Verification and Validation). There are two types of ASIC, one is a full customized type, the other is a half customized type. PLD(Programmable Logic Device) used in this paper is a half customized ASIC which is a device consisting of blocks of logic connected with programmable interconnections that are customized in the package by end users. This paper describes the RPS(Reactor Protection System) composed of ASICs which provides emergency shutdown of the reactor to protect the core and the pressure boundary of RCS(Reactor Coolant System) in NPP's. The RPS is largely composed of five logic blocks, each of them was implemented in one PLD, as the followings. A). Bistable Logic B). Matrix Logic C).Initiation Logic D). MMI(Man Machine Interface) Logic E). Test Logic.

• Nuclear Engineering and Technology
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• 제47권4호
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• pp.443-453
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• 2015

A hybrid safety injection tank (H-SIT) can enhance the capability of an advanced power reactor plus (APR+) during a station black out (SBO) that is accompanied by a severe accident. It may a useful alternative to an electric motor. The operations strategy of the H-SIT has to be investigated to achieve maximum utilization of its function. In this study, the master logic diagram (i.e., an analysis for identifying the differences between an H-SIT and a safety injection pump) and an accident case classification were used to determine the parameters of the H-SIT operation. The conditions that require the use of an H-SIT were determined using a decision-making process. The proper timing for using an H-SIT was also analyzed by using the Multi-dimensional Analysis of Reactor Safety (MARS) 1.3 code (Korea Atomic Energy Research Institute, Daejeon, South Korea). The operation strategy analysis indicates that a H-SIT can mitigate five types of failure: (1) failure of the safety injection pump, (2) failure of the passive auxiliary feedwater system, (3) failure of the depressurization system, (4) failure of the shutdown cooling pump (SCP), and (5) failure of the recirculation system. The results of the MARS code demonstrate that the time allowed for recovery can be extended when using an H-SIT, compared with the same situation in which an H-SIT is not used. Based on the results, the use of an H-SIT is recommended, especially after the pilot-operated safety relief valve (POSRV) is opened.

• Nuclear Engineering and Technology
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• 제28권6호
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• pp.594-601
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• 1996

To assure quality of safety critical software, software should be developed in accordance with software development procedures and rigorous software verification and validation should be performed. Software verification is the formal act of reviewing, testing or checking, and documenting whether software components comply with the specified requirements for a particular stage of the development phase [1]. New software verification methodology was developed and was applied to the Shutdown System No. 1 and 2(SDS1,2) for Wolsong 2, 3 and 4 nuclear power plants by Korea Atomic Energy Research Institute(KAERI) and Atomic Energy of Canada Limited(AECL) in order to satisfy new regulation requirements of Atomic Energy Control Board(AECB). Software verification methodology applied to SDS1 for Wolsong 2, 3 and 4 project will be described in this paper. Some errors were found by this methodology during the software development for SDS1 and were corrected by software designer. Output from Wolsong 2, 3 and 4 project have demonstrated that the use of this methodology results in a high quality, cost-effective product.

• Nuclear Engineering and Technology
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• 제27권3호
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• pp.327-335
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• 1995

원자로의 가동중지 중이나. 재장전시 중기 발생기의 세관검사 및 보수작업을 병행하면 원전의 운전정지보수기 간을 현저하게 단축할 수 있다. 이때 원자로가 설치되어 있는 수조의 냉가수가 중기발생기내로 유입되는 것을 막는 장비로써 노즐댐이 있다. 노즐댐의 설치는 고방사선환경과 제한된 공간에서 작업을 해야 하는 특수성 때문에 작업자들이 기피하는 현상을 보인다. 현재 쓰이고 있는 무거운 노즐댐은 노즐댐설치 및 제거작업에 장애가 되는 가장 큰 요인이다. 본 논문에서는 노즐댐의 재질선정과 구조설계를 병행하여 현재 쓰이고 있는 노즐댐보다 가벼우면서도 굽힘강성 대 무게비와 비 강도가 증가된 노즐댐을 설계하였으며, 탄소섬유강화 복합재료로 경량노즐댐을 제작 완료하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2215-2217
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• 2003

In this paper we describe a Control Rod Control System(CRCS) with the various functions for the test and operation of Control Rod Drive Mechanism(CRDM). The CRCS controls the motion of the full length rod drive mechanisms in response to signals from the Reactor Operator and the Reactor Regulating System. The mechanisms are grouped and identified as being for either Shutdown Banks or Control Banks. The CRCS also provides information regarding rod motion, rod position, and status of the Rod Control System. Also we have implemented the diverse functions in the developed CRCS. Due to the developed CRCS, we are assured that the commercial operation by this system be made before long.

• 전기학회논문지
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• 제66권2호
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• pp.305-314
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• 2017

Most of the existing researches on systemwide optimization of generator maintenance scheduling do not consider the equivalent operating hours(EOHs) mainly due to the difficulties of calculating the EOHs of the CCGTs in the large scale system. In order to estimate the EOHs not only the operating hours but also the number of start-up/shutdown during the planning period should be estimated, which requires the mathematical model to incorporate the economic dispatch model and unit commitment model. The model is inherently modelled as a large scale mixed-integer nonlinear programming problem and the computation time increases exponentially and intractable as the system size grows. To make the problem tractable, this paper proposes an EOH calculation based on demand grouping by K-means clustering algorithm. Network congestion is also considered in order to improve the accuracy of EOH calculation. This proposed method is applied to the actual Korean electricity market and compared to other existing methods.