• Journal of Energy Engineering
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• v.21 no.1
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• pp.75-80
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• 2012

In this paper a realistic bounding method for flooding analysis following rupture of large size of thanks and piping is defined. Mass and energy release during main feedwater line break accident is analyzed with RETRAN code. It is modeled that the main feed water control valve is closed in 5.0 seconds after reactor trip. In result of the analysis, largest mass and energy is discharged at 70% reactor power. The flood sources for main feedwater room are calculated when piping failure occurs in the high energy line and medium energy line. Based on the result of flood level (1.43m), it is investigated that all of the safety-related environmental qualification equipments are well located above the flood level.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.244-251
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• 2015

The containment filtered venting system reduces the range of the contamination area around the nuclear power plant by strengthening the integrity of the containment building. In this study, the probabilistic assessment code MACCS2 was used to assess the effect of the CFVS to off-site. The accident source term was selected from a Probabilistic Safety Analysis report of SHINKORI 1&2 Nuclear Power Plant. The three source term categories from 19 STC were chosen to evaluate the effective dose and thyroid dose of residents around the power plant and the dose with CFVS and without CFVS were compared. The dose was calculated according to the distance from the nuclear power plant, so the damage scale based on the distance that exceeds the IAEA criteria for effective dose (100 mSv per 7 days) and thyroid dose (50 mSv per 7 days) were compared. The effective dose reduction rates of the STC-3, STC-4, STC-6 were about 95-99% in the whole range (0~35 km), 96-98% for the thyroid dose. There are similar results between effective dose and thyroid dose. After applying the CFVS, the damage scale that exceeds the effective dose criteria was about 1 km (mean). Especially, the STC-4 damage scale was decreased from 26 km (mean) to 1.2 km (mean) significantly. The damage scale that exceed the thyroid dose criteria was decreased to 2~3 km (mean). The STC-4 damage scale was also decreased significantly as compared to STC-3, STC-6 in terms of effective dose.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.255-262
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• 2011

In a loss-of-coolantaccident, considerable debris may be generated and transported to the recirculation sump. The accumulation of debris will reduce the netpositivesuctionhead and threaten the safety of thenuclear power plant. Both NEI 04-07 and USNRC SER suggesteda CFD methodology. However, additional investigation is needed to consider the unique characteristics of nuclear power plants. The transport of the generated debris is strongly influenced by the break location and the plant characteristics, including the configuration.In this paper, a CFD methodology for blow-down transport evaluation is proposed and applied to an OPR1000 nuclear power plant. The results show that the percentage of small debris transported to the upper containment is 32%, which is 7% larger than the valuegiven in the NEI 04-07 baseline analysis. This result may be used as a point of reference in future analytical studies.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.1
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• pp.25-36
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• 2021

Hydrogen in hydrogen-electric vehicles has a wide range of combustion and explosion ranges, and is a combustible gas with a very fast flame propagation speed, so it has the risk of leakage, diffusion, ignition, and explosion. The fuel tank has a Thermally active Pressure Relief Device (TPRD) to reduce the risk of explosion and other explosions, and in the event of an accident, hydrogen inside the tank is released outside before an explosion or fire occurs. However, if an accident occurs in a semi-closed space such as an underground parking lot, the flow of air flow is smaller than the open space, which can cause the concentration of hydrogen gas emitted from the TPRD to accumulate above the explosion limit. Therefore, in this study, the leakage rate and concentration of hydrogen over time were analyzed according to the diameter of the nozzle of the TPRD. The diameter of the nozzle was considered to be 1 mm, 2.5 mm and 5 mm, and ccording to the diameter of the nozzle, the concentration of hydrogen in the underground parking lot increases in a faster time with the diameter of the nozzle, and the maximum value is also analyzed to be larger with the diameter of the nozzle. In underground parking lots where air currents are stagnant, hydrogen concentrations above LFL (Lowe Flammability Limit) were analyzed to be distributed around the nozzle, and it was analyzed that they did not exceed UFL (Upper Flammability Limit).

• Nuclear industry
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• no.9_10 s.9
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• pp.38-40
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• 1982

스웨덴의 원자로 marker Asea-Atom사는 지역난방(DH)용 원자로로 SECURE를 개발했다. 이 원자로는 (1) 저온도, 저압력, (2) 본질적인 안전성(기술적 안전시스템에 의하지 않은)에 의해 로의 정지${\cdot}$냉각이 어떠한 상황아래에서도 보증된다, (3) 사고시에 운전원에 의한 조작을 필요로 하지 않는다, (4) 출력밀도가 낮기 때문에 핵분열생성물질의 방출 우려가 적다는 등의 특징을 가지며 그 안전성으로 인해 도시부근에 위치할 수 있으며 또한 경제적으로도 석유나 석탄을 연소시키는 boiler보다 훨씬 유리하다.

• Electronics and Telecommunications Trends
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• v.11 no.2 s.40
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• pp.31-43
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• 1996

본 고에서는 인간이 사고와 행동을 할 때 뇌에서 자발적으로 방출되는 뇌파를 미래의 통신시스템 및 서비스에 이용하기 위한 전단계로서, $\alpha$, $\beta$, $\delta$, $\theta$, $\gamma$및 $\mu$파 등 뇌파의 종류 및 특성과 국제적으로 사용되고 있는 10-20 방식에 의한 뇌파측정점, 그리고 전극배치법에 대해 고찰해보고, 뇌파인식에 관한 최근 연구동향을 분석하였다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.11a
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• pp.77-78
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• 2002

원자력시설이나 원자력발전소에서 사고가 발생하여 대기로 방출된 방사능물질은 두 가지 주요경로를 통해 인체노출이 일어난다 첫째는 지역내 대기중에 존재하는 방사성물질이 인체의 호흡이나 피부 등을 통해 체내로 흡입되는 직접적인 노출 (Direct Exposures)이고 다른 하나는 방사능물질이 대기로부터 주변의 토양에 침적하고 이러한 토양에서 재배된 오염된 농작물들 (쌀, 보리, 밀, 또는 과일, 채소)을 인간이 섭취하거나, 방사능물질에 오염된 목초로 키운 축산물(소, 돼지, 닭 등)과 이들로 생산하는 제품들(우유, 고기, 달걀 등)을 인간이 섭취함으로써 이루어지는 보다 간접적인 인체노출(Indirect Exposures)이 있을 수 있다. (중략)

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.457-462
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• 1997

원전에서 정상가동시 또는 사고시 대기중으로 방출된 방사성 물질에 의한 주변환경 및 주민들의 영향을 보다 정확히 평가하기 위해 월성원전을 대상으로 부지 주변지역의 해륙풍 등과 같은 국지순환을 세밀하게 모사할 수 있는 삼차원 미세 격자계 해륙풍 모델을 개발하였다. 개발된 모델을 이용하여 봄철 약한 북풍이 부는 밝은 날에 대해 월성원전 주변지역의 해륙풍 발달ㆍ소멸, 해풍의 내륙 진입거리 및 해륙풍의 연직구조 등을 모사하고, 모사 결과를 관측값과 비교하여 모델의 특성을 파악하였다.

• JOURNAL OF ELECTRICAL WORLD
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• s.282
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• pp.67-71
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• 2000

일본, 유럽 및 미국 등의 선진국에서는 전력인프라가 거의 정비되어, 새로운 전력설비에 대한 투자보다 설비의 유지 보수$\cdot$점검비용의 비율이 더 커져가고 있다. 이러한 환경 하에 정기적인 유지보수$\cdot$점검에 요하는 비용, 사고시의 복구에 소요되는 비용 및 정전으로 인한 손실 등을 포함하여 라이프사이클 코스트의 최적화가 논의되고 있다. 유지보수$\cdot$점검에 대하여는 종래의 정기적인 유지보수(Time Based Maintenance : TBM)에서 상태대응 유지보수(Condition Based Maintenance : CBM)에로의 이행으로 비용을 삭감하려는 시도도 진전되고 있다. 이 때문에 전력설비의 상태를 파악할 수 있는 적절한 센서의 설치와 저가격의 가반형 센서의 도입도 추진되고 있다. 또한 설비의 진단장치를 차에 실은 이동진단차의 도입도 시작되고 있어, 복수의 전력소를 순회하며 효율 좋은 유지보수$\cdot$점검을 할 수 있게 되었다. EH 변전소의 무인화에 따라 정전시간 단축을 위해 사고 시에 원방복구조작이 가능한 고장점 표정장치도 도입되고 있다. 최근에는 SF${_6}$가스의 환경문제도 화제가 되어 가스를 대기 중에 방출하는 일 없이 고장구분을 표정할 수 있는 분해가스센서도 개발되었다.

• Journal of Radiation Protection and Research
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• v.20 no.1
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• pp.53-64
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• 1995

The radiation fields following the large loss of coolant accident (LOCA) have been assessed for the vital areas in the service building of Wolsong 2, 3, and 4 nuclear power plants. The ORIGEN2 code was used in calculating the fission product inventories in the fuel. The source terms were based upon the activity released following the dual failure accident scenario, i.e., a LOCA followed by impaired emergency core cooling (ECC). Configurations of the reactor building, the service building, and the ECC system were constructed for the QAD-CG calculations. The dose rates and the time-integrated doses were calculated for the time period of upto 90 days after the accident. The results showed that the radiation fields in the vital access areas were found to be sufficiently low. Some areas however showed relatively high radiation fields that may require limited access.