• Nuclear Engineering and Technology
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• 제31권4호
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• pp.375-384
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• 1999

The credibility of CHECWORKS FAC model analysis was evaluated for plant application in a model plant chosen for demonstration. The operation condition at each pipe component was defined before the wear rate analysis by plant data base, water chemistry analysis, and network flow analysis. The predicted wear was compared with the measured wear for 57 sample components selected from 43 susceptible line groups analysed. The inspected 57 locations represent components of highest predicted wear in each line group. Both absolute value and relative ranking comparisons indicated reasonable correlations between the predicted and the measured values. Four components showed much higher measured wear rates than the predicted ones in the feed water train from main feed water pump discharge to steam generator, probably due to high hydrazine concentration operation the effect of which had not been incorporated into the CHECWORKS model. The measured wear was higher than the predicted one consistently for components with least susceptibility to FAC. It is believed that the conservatism maintained during UT data analysis dominated the measurement accuracy. A great deal of enhancement is anticipated over the current plant pipe management program when a comprehensive plant pipe management program is implemented based on the model analysis.

• 조명전기설비학회논문지
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• 제23권12호
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• pp.83-89
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• 2009

최근 국내 전력산업의 주변 환경, 즉 전기요금의 가격, 환경보호 및 에너지 문제 등으로 인해 전기사업을 보다 능동적으로 운영하기 위한 필요성이 제기되고 있다. 지금까지 대부분의 전력회사에서는 전력계통의 신뢰도에 중점을 두고 전력을 공급하였지만 모든 조건에 일률적으로 적용하는 것은 막대한 비용 상승을 동반하기 때문에 전력회사에서는 전력설비를 설치 또는 운영하는 것에 대해 보다 유연하게 대처하기 위하여 기기 투자비용에 대한 가치 및 이득을 검토하는 것이 필요하다. 따라서 본 연구에서는 지중배전기기의 설치위치별로 국외 사례 및 국내 환경을 고려하여 그 효과를 분석하였으며, 본 연구결과는 향후 지중배전기기의 현장 적용 시 검토방안과 대책으로써 활용이 기대된다.

• 한국산학기술학회논문지
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• 제21권12호
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• pp.52-59
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• 2020

현행 국내의 주택용 전기요금은 월 전력 사용량에 따라 누진 단계를 적용하여 부과하는 방식으로 전기사용량이 많을 경우 전기요금이 급격하게 상승하는 구조로 이루어져 있다. 이러한 획일화된 전기요금 누진제는 소비자의 전력소비 패턴에 대한 고려가 부족한 점과 소비자의 선택권을 제한하는 측면에서 한계가 있다. 이에 산업통상자원부와 한국전력공사에서 계절과 시간대별 전기사용량에 따라 전기요금을 부과하는 방식인 주택용 계시별 요금제 기반의 실증이 이루어지고 있다. 본 논문에서는 대도시 소재 아파트 단지 5개동 362세대의 5년간 AMI 데이터 분석을 통해 10개의 전기사용 패턴을 도출하였다. 도출된 패턴을 국내의 기존 요금제인 주택용 전기요금제 및 현재 실증에 적용하고 있는 계시별 요금제인 일반형과 집중형 요금제 등 3개 요금제와 미국과 호주의 계시별 요금제 3개에 적용하여 각 패턴 별 선택형 요금제의 효과를 전기요금 편익 측면에서 분석한 결과 기존 요금제 대비 5개 패턴에서는 편익이 발생하였고 5개 패턴에서는 오히려 전기요금이 증가하였으며 이러한 현상은 실증 중인 국내요금을 포함하여 해외 요금제에서도 동일한 현상을 보이고 있음을 확인하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제2권1호
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• pp.19-23
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• 2000

We are developing a small-sized superconducting magnetic energy storge ($\mu$SMES) magnet with the storage capacity of a few megajoules, which provides electric power with high quality to sensitive electric loads. A kA class superconductor with a high coppe $r^erconductor ratio was selected as a candidate conductor. The superconductor was tested in two points of view, which are basic and important in development of the $\mu$SMES magnet. First, stabilities of the superconductor against localized disturbances such as wire motions were estimated by using a wire heater. Second, the quench current characteristics for different charge rates were also tested. The stability data showed that the short heat pulses made the conductor more unstable. The superconductor had relatively high recovery currents ranging between 40% and 50% of its critical currents. The quench tests indicated that the quench currents of the conductor were independent of current ramp rates up to 3000 A/s and nearly equal to its cuitical current data.ta.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(2)
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• pp.123-128
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• 1997

The effects of heat treatment on fatigue crack growth rates (FCGRs) of Inconel 690 have been investigated in terms of carbide morphology and grain size. Cycling tests in air at room temperature have shown that FCGR in low stress intensity factor range (ΔK) region can be effectively reduced by increasing the grain boundary carbide precipitate size and grain size. Decrease in FCGR is attributed to the crack tip blunting at the precipitates of grain boundary chromium carbides.

• Corrosion Science and Technology
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• 제14권1호
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• pp.33-39
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• 2015

Pipe wall-thinning by flow-accelerated corrosion and various types of erosion is significant damage in secondary system piping of nuclear power plants(NPPs). All NPPs in Korea have management programs to ensure pipe integrity from degradation mechanisms. Ultrasonic test(UT) is widely used for pipe wall thickness measurement. Numerous UT measurements have been performed during scheduled outages. Wall-thinning rates are determined conservatively according to several evaluation methods developed by Electric Power Research Institute(EPRI). The issue of reliability caused by measurement error should be considered in the process of evaluation. The reliability analysis method was developed for single and multiple measurement data in the previous researches. This paper describes the application results of reliability analysis method to real measurement data during scheduled outage and proved its benefits.

• 한국군사과학기술학회지
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• 제23권3호
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• pp.237-245
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• 2020

In this paper, I introduce Phase-Change Cooling for thermal management of high power devices that can be applied to High Power Laser and Electric Propulsion Systems which are composed of multiple distributed superheat sources. Phase-Change Cooling can be good used to efficient cooling of their heat sources. Phase-Change Cooling has extremely high efficiency of two-phase heat transport by utilizing heat of vaporization, relatively low flow rates and reduced pumps power. And I suggest TPI(Thermal Performance Index) which is a quantitative performance index of Phase-Change Cooling for thermal management. I quantify the performance of Phase-Change Cooling by introducing TPI. I present the test results of TPI's changing refrigerant, heat sink and flow rate of the Phase-Change Cooling system through the experiments and analyze these results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.82-85
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• 1993

The load forecasting has been essential in planning and operation of power systems. The load composition rata is also needed to analyze power-systems - load flow calculation and system stability. This paper proposes the monthly peak load forecasting methods for load groups in residential class using load composition rate and electric consumption characteristics. The proposed methods were applied to a real-scale power system and the effectiveness was turned out.

• Journal of Radiation Protection and Research
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• 제32권2호
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• pp.45-50
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• 2007

본 연구는 한국인 특성에 대해 보다 신뢰할 수 있는 방사성핵종의 체내 흡수선량 평가를 위한 일환으로 $^{131}I$을 선정하여 체내 각 장기별 잔류율 및 소변 일일배설률을 측정하였다. 실험방법은 성인남성 28명을 대상으로 $^{131}I$을 경구 투여한 후, 시간대별(2, 4, 6, 24시간) 갑상선, 간, 위, 소장, 신장, 소변의 방사능을 측정하고 이를 이용하여 각 장기별 잔류율 및 소변 일일배설률을 산출하였다. 그 결과, $^{131}I$ 투여 24시간 후 갑상선이 평균 19.70%의 잔류율과 71.12%의 소변 일일배설률을 나타냈으며, 갑상선을 제외한 각 장기는 투여 2시간 후 최고 잔류율 및 최고 소변 일일배설률을 보이나, 이후 감소하는 경향을 보였다. 또한 잔류율이 높은 장기 순서는 갑상선을 제외하고 위, 왼쪽 신장, 간, 소장, 오른쪽 신장으로 나타났다. 본 연구를 통해 산출된 방사성옥소의 섭취 24시간 후 갑상선 잔류율 변화는 기존 30%로 보고된 ICRP-54/67 및 25% 잔류율로 보고된 ICRP-78의 자료와 차이를 나타냈다. 한국인의 특성에 맞는 체내 흡수선량 평가의 올바른 접근과 그에 따른 기초 자료의 확보는 향후 원자력 발전소의 작업 종사자 내부피폭 및 임상에서 발생 가능한 체내 피폭의 정량적 평가에 도움을 줄 수 있을 것으로 판단된다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.443-447
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• 2001

A laboratory-scale electrodewatering system for enhancing conventional filter pressure dewatering by an electric field has been developed to decrease the water content of sludge generated in the wastewater treatment. It consists of a piston-typed filter press, a power supply and data acquisition system. The offset of electrodewatering is investigated as a function of applied pressure, applied voltage, sludge type and filtration time. Also the optimal conditions for maximizing the dewatering efficiency in the eletrodewatering system are investigated. Electric field strength and mechanical pressure are in the range of from 0 to 120 V/cm and from 98.1 to 392.4 kPa. The dewatering rates increased with increasing electric strength. These experiments produced a final sludge cake with water content of 60 wt% using electrodewatering technology, compared with a 80 wt% using pressure filtration alone. The conventional filtration system using the electrodewatering shows the potential to be effective method for improving dewatering Sludge.