• KIEE International Transactions on Power Engineering
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• 제3A권1호
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• pp.53-60
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• 2003

At present the electric power industry in Korea is going through a major restructuring process. The restructuring is motivated by a desire to reduce electricity supply costs, to attract new in-vestment in modern generation, transmission and distribution facilities, and to stimulate innovation in the wholesale production and the retail supply of electricity. The experience to date shows that restructuring of electric power industry in the US, however, is marred with a number of problematic market performances including unreasonably high prices at wholesale. This paper investigates the important role of Power Exchange for stabilizing electric power industry in transition by offering various financial products. These financial products are used for risk hedging by the market participants. The paper focuses on the risk hedging by an individual supplier and derives an explicit decision rule that incorporates the attitude towards the risks. In addition to providing the financial products for risk hedging by market participants, the Power Exchange plays another very important role of financial safeguard system. Because of its unique characteristics, the Power Exchange is well suited for financial surveillance where it performs the early detection of unsound financial (and to a large extent operational) practices on the part of any system users and protect the system integrity and the market participants from the consequences of a default in the clearing structure.

• 대한기계학회논문집A
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• 제23권6호
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• pp.881-894
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• 1999

Cylindrical plunge grinding is widely used for final machining process of precision parts such as automobile, aircraft, measurement units. But in order to make parts which have high precision accuracy and high surface integrity, it is necessary to consider grinding characteristics due to accumulation phenomena of grinding wheel in plunge grinding process. In this study, in order to examine closely plunge grinding process, grinding power, grinding force, real depth of cut are monitored in transient state, steady state and spark out state. As the result, it is shown that grinding power and force are affected by dressing condition, depth of cut and speed ratio and that there exist threshold grinding force and it also affected by dressing condition. Also considered effects of grinding conditions on surface roughness and roundness of workpiece

• 대한기계학회논문집B
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• 제38권4호
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• pp.311-320
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• 2014

풍력터빈 블레이드는 바람의 운동에너지를 기계적 에너지로 변환하는 장치로써 풍력발전시스템의 출력성능, 에너지변환효율, 하중 및 동적 안정성에 영향을 미칠 수 있기 때문에 주요부품으로 분류된다. 따라서 최적의 블레이드 설계결과를 얻기 위해서는 시스템 특성이 고려된 공력-구조 통합설계가 중요하며, 국제표준 또는 인증기관의 가이드라인에 따른 설계평가를 통해 구조건전성의 검증이 요구된다. 본 연구에서는 블레이드 설계 인증 시 요구되는 평가항목 및 판정기준에 대한 상세해설과, (사)한국선급의 인증기준에 따른 2 MW 급 블레이드(KR40.1b)에 대한 설계평가 결과를 제시하였다. 유한요소 해석에 의한 극한 강도, 좌굴 안정성, 한계 허용 팁 변형과 누적 손상 법에 의한 피로 강도 해석결과가 검토되었으며, KR40.1b 블레이드는 모든 평가항목에 대한 구조 건전성을 만족하는 것으로 확인되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.636-643
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• 2001

Interference between the crossover leg of the reactor coolant system (RCS) and the pipe whip restraints (PWR) has brought a degradation issue of the integrity of the Reactor Coolant System in Westinghouse type nuclear power plants (NPPs) of Korea. According to the gap Inspect ion carried out during planned overhaul (Year 2000), interference between the crossover leg and the PWR was found in each RCS loop. This plant has had the high vibration problem on the RC pump 'B'. The reason for the high vibration in the RC pump 'B' had been massively surveyed and it was found that the crossover leg of RCS contacted with the PWR in hot condition. Since the contact between the crossover leg and the PWR changes the dynamic characteristics of the piping system for the RCS, this is considered as one reason for the high vibration. And a possibility of overstress on the crossover leg due to the contact with the PWR should be evaluated. Through performing RCS integrity analyses, subsequent actions were initiated to increase the gap between those parts. As the results of the appropriate separation between two parts, it was reported that there was no unusual noise or vibration during plant heat-up. In this paper, the evaluations for the gap between the crossover leg and the PWR and the structural integrity due to loop binding is described.

• 대한토목학회논문집
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• 제42권6호
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• pp.775-786
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• 2022

원자력발전소 구조물을 포함하여 플랜트 구조물에서는 사용 중 설비보강을 위하여 벽체 및 슬래브에 관통부를 신설하는 경우가 빈번히 발생하고 있으며, 관통부 설치작업 중에 철근이 절단되는 사례가 일부 발생하고 있다. 이 관통부들은 설계 또는 건설 단계에서 고려된 것이 아니므로 설치 중 발생한 철근의 절단은 사실상 구조물의 손상이기 때문에, 관통부 주변 응력 전이범위 또는 유효폭을 고려한 구조물의 건전성 평가가 필요하다. 본 연구에서는 가동중인 원자력발전소 벽식 건물의 전단벽에 관통부를 신설할 경우에 발생하는 철근 절단의 영향을 평가하기 위하여 다양한 비선형 해석과 정적 가력 실험을 수행하였다. 그리고 관통부 신설과 철근의 절단으로 인한 벽체의 강성저하와 관통부 주변 철근의 응력 및 변형률 분포를 평가하였다.

• Nuclear Engineering and Technology
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• 제45권3호
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• pp.377-384
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• 2013

During the last three decades, South Korean nuclear power plants have discharged about 5,950 tons of spent fuel and the maximum burn-up reached 55 GWd/MTU in 2002. This study was performed to support the development of Korean dry spent fuel storage alternatives. First, we chose V5H-$17{\times}17$ and KSFA-$16{\times}16$ as representative domestic spent fuels, considering current accumulation and the future generation of the spent fuels. Examination reveals that their average burn-ups have already increased from 33 to 51 GWd/MTU and from 34.8 to 48.5 GWd/MTU, respectively. Evaluation of the fuel characteristics shows that at the average burn-up of 42 GWd/MTU, the oxide thickness, hydrogen content, and hoop stress ranged from $30{\sim}60{\mu}m$, 250 ~ 500 ppm, and 50 ~ 75 MPa, respectively. But when burn-up exceeds 55 GWd/MTU, those characteristics can increase up to 100 ${\mu}m$, 800 ppm, and 120 MPa, respectively, depending on the power history. These results demonstrate that most Korean spent nuclear fuels are expected to remain within safe bounds during long-term dry storage, however, the excessive hoop stress and hydrogen concentration may trigger the degradation of the spent fuel integrity early during the long-term dry storage in the case of high burn-up spent fuels exceeding 45 GWd/MTU.

• 한국안전학회지
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• 제26권5호
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• pp.41-45
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• 2011

The fire event occurred in fire proof zone often causes serious electrical problems such as shorts, ground faults, or open circuits in nuclear power plants. These would be directed to the loss of safe shutdown capabilities performed by safety related systems and equipments The fire event can treat the basic design principle that safety systems should keep their functions with redundancy and independency. In case of a cable fire, operators can not perform their mission properly and can misjudge the situation because of spurious operation, wrong indication or instrument. These would deteriorate the plant capabilities of safety shutdown and make disastrous conditions. In this paper, the cables of the representative nuclear power plant in korea is selected and the cable functional failure temperature by exposed fire using Cable Response to Live Fire(CAROLFIRE) is studied. It is expected that the results are very useful to know the cable failure temperature by exposed fire. We confirmed the safety and integrity of the cable by exposed fire and those results will use the based data of cable exposed fire characteristics.

• 전산구조공학
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• 제6권2호
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• pp.79-86
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• 1993

원자력발전소중 안전과 관련된 구조물은 지진의 가능성에 대비하여 그의 구조적 안전성과 가용성이 검증되어야 한다. 본 논문은 원자력발전소 보호시스템 캐비넷을 예를 들어 그에 대한 내진검증 방법을 보였다 캐비넷의 유한요소모델을 작성하여 동특성을 구하였고 그 모우드값을 입력지진스펙트럼과 비교한 결과 구조물의 1차 모우드가 입력 스펙트럼의 peak와 일치함으로써 설계변경의 필요성이 대두되었다. 이 peak값을 피하기 위하여 캐비넷의 구조를 변경하였고 변경된 구조물에 대하여 응답스펙트럼해석과 시간이력해석을 수행하여 구조적 건전성과 가용성을 보임으로써 설계변경된 캐비넷의 내진검증을 확인하였다.

• 한국유체기계학회 논문집
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• 제2권2호
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• pp.13-18
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• 1999

The pump safety related to the functions in nuclear power plants must be designed to meet load conditions considering seismic requirements. In order to satisfy both structural integrity and operability of these pumps, the initial step in the seismic qualification is to establish the resonant frequencies of the structure. Applications we made to the design of the vertical and horizontal type pump. Computational results are analyzed with respect to the dynamic characteristics and are compared to the expected design requirements.

• Journal of Information Processing Systems
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• 제5권4호
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• pp.187-196
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• 2009

This paper presents compact cryptographic hardware architecture suitable for the Mobile Trusted Module (MTM) that requires low-area and low-power characteristics. The built-in cryptographic engine in the MTM is one of the most important circuit blocks and contributes to the performance of the whole platform because it is used as the key primitive supporting digital signature, platform integrity and command authentication. Unlike personal computers, mobile platforms have very stringent limitations with respect to available power, physical circuit area, and cost. Therefore special architecture and design methods for a compact cryptographic hardware module are required. The proposed cryptographic hardware has a chip area of 38K gates for RSA and 12.4K gates for unified SHA-1 and SHA-256 respectively on a 0.25um CMOS process. The current consumption of the proposed cryptographic hardware consumes at most 3.96mA for RSA and 2.16mA for SHA computations under the 25MHz.