• 한국수소및신에너지학회논문집
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• 제33권4호
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• pp.383-390
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• 2022

Appropriate explosion proof electrical equipment should be installed in hazardous areas. In areas where hydrogen is handled, explosion proof electrical equipment adjacent to the hydrogen handing facility must be reviewed for selection of gas group IIC (or IIB+H₂) equipment. When selecting explosion proof electrical equipment for the flammable substance handling facility in areas where hydrogen and flammable substance are handled, the method to avoid gas group IIC (or IIB+H₂) equipment has been suggested by using the operating pressure of the hydrogen handling facility. When the operating pressure of the outdoor hydrogen handling facility is 1.065 MPa or less, it has been confirmed that there is no need to install gas group IIC (or IIB+H₂) equipment for the flammable substance handling facility adjacent to the hydrogen handling facility. And the method of selecting explosion proof electrical equipment for the flammable substance handling facility has been suggested as a flowchart, so it will be able to be utilized when selecting appropriate explosion proof electrical equipment.

• 신재생에너지
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• 제19권3호
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• pp.1-12
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• 2023

This study aims to evaluate the optimal size of the hydrogen facility to be installed in a zero-energy district in terms of load matching and facility efficiency. A mismatch between energy generation and consumption is a common occurrence in zero-energy districts. This mismatch adversely effects the energy grid. However, using an energy carrier such as hydrogen can solve this problem. To determine the optimal size of hydrogen fuel cells to be used on-site, simulation of hydrogen installation is required at both district-and building- levels. Each case had four operating schedules. Therefore, we evaluated eight scenarios in terms of load matching, heat loss, and facility operational efficiency. The results indicate that district-level installation of hydrogen facilities enables more efficient energy use. Additionally, based on the proposed model, we can calculate the optimal size of the hydrogen facility.

• 한국수소및신에너지학회논문집
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• 제19권3호
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• pp.239-247
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• 2008

Hydrogen production facility using very high temperature gas cooled reactor lies in situation of high temperature and corrosion which makes hydrogen release easily. In that case of hydrogen release, there lies a danger of explosion. However, from the point of thermal-hydraulics view, the long distance of them makes lower efficiency result. In this study, therefore, outlines of hydrogen production using nuclear energy are researched. Several methods for analyzing the effects of hydrogen explosion upon high temperature gas cooled reactor are reviewed. Reliability physics model which is appropriate for assessment is used. Using this model, leakage probability, rupture probability and structure failure probability of very high temperature gas cooled reactor are evaluated and classified by detonation volume and distance. Also based on standard safety criteria which is value of $1{\times}10^{-6}$, safety distance between the very high temperature gas cooled reactor and the hydrogen production facility is calculated.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.131-136
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• 2004

The ongoing developmental studies on the application of hydrogen peroxide for propulsion are briefly reviewed. A detailed design-study of a laboratory scale facility of a hydrogen peroxide mono-propellant engine of 100-N thrust is presented. For the preparation of concentrated hydrogen peroxide, a distillation facility has been realized. Results of water analogy tests are presented. Initial firings using the concentrated hydrogen peroxide were not successful. Low environmental temperature, low contact area of the catalyst pack, and contamination in the hydrogen peroxide were considered to be the reasons. Addressing the first two points resulted in successful firing of the rocket engine.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 추계학술발표회논문집(1)
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• pp.495-500
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• 1997

For hydrogen management in severe accidents with degraded nuclear core of PWR's, several experiments have been performed in the SNU hydrogen mixing facility. The objectives are understanding the extent of hydrogen mixing and analyzing the effects of factors which dominate uniform or non-uniform mixing at compartments in the containment building. The facility represents on a 1/11th linearly scaled model of the YGN unit 3&4, hydrogen was simulated by helium. Because there are the gaps between safety injection tank and compartment layers in the containment, the test facility was constructed in three dimentinal mode for analyzing of mixture behavior through the gaps. From the experimental results we could conclude that overall hydrogen concentration distributed uniformly in the free volume of the test compartment, but fluctuated in the gaps. This paper is focused on experimental result from several experiment.

• Safety and Health at Work
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• 제12권3호
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• pp.416-420
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• 2021

Hazardous area classification design is required to reduce the explosion risk in process plants. Among the international design guidelines, only IEC 60079-10-1 proposes a new type of zone, namely zone 2 NE, to prevent explosion hazards. We studied how to meet the zone 2 NE grade for a facility handling hydrogen gas, which is considered as most dangerous among explosive gases. Zone 2 NE can be achieved considering the grade of release, as well as the availability and effectiveness of ventilation, which are factors indicative of the facility condition and its surroundings. In the present study, we demonstrate that zone 2 NE can be achieved when the degree of ventilation is high by accessing temperature, pressure, and size of leak hole. The release characteristic can be derived by substituting the process condition of the hydrogen gas facility. The equations are summarized considering relation of the operating temperature, operating pressure, and size of leak hole. Through this relationship, the non-hazardous condition can be realized from the perspective of inherent safety by the combination of each parameter before the initial design of the hydrogen gas facility.

• Corrosion Science and Technology
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• 제8권4호
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• pp.133-138
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• 2009

For the corrosion protection of the natural gas transmission pipelines, two methods are used, cathodic protection and coating technique. In the case of cathodic protection, defects are embrittled by occurring hydrogen at the crack tip or material surface. It is however very important to evaluate whether cracks in the embrittled area can grow or not, especially in weld metal. In this work, on the basis of elastic plastic fracture mechanics, we performed the CTOD testing with various test conditions, such as testing rate and potential. The CTOD of the base metal and the weld metal showed a strong dependence of the test conditions. The CTOD decreased with decreasing testing rate and with increasing cathodic potential. The morphology of the fracture surface showed the quasi-cleavage at low testing rate and cathodic overprotection. The low CTOD was caused by hydrogen embrittlement at crack tip.

• 한국가스학회지
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• 제27권4호
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• pp.116-122
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• 2023

본 연구는 탄소중립 사회 실현을 위해 추진 중인 국제사회(한국, 미국, 유럽, 일본 등)의 수소경제 동향 분석과 더불어, 국민과 밀접한 핵심 수소 사용시설인 기존 구축·운영 중인 기체수소충전소와 향후 구축 예정인 액화수소충전소의 유형별 차이점을 비교·분석하였다. 또한, 정량적 위험성평가 프로그램인 SAFETI를 활용하여 액화수소충전소의 안전성을 분석하고, 조건부 허용영역인 개인적·사회적 위험도와 설비별 위험도 순위를 고려하여 설비 배치 등의 안전성 제고 방안에 대해 제안하였다.

• 한국가스학회지
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• 제26권6호
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• pp.59-64
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• 2022

현재 수소운송설비는 2022년 10월 말 기준 787대가 운행 중이며, Type 1 이음매 없는 용기에 최대 200 bar의 압력으로 1회 최대 340 kg을 운송한다. 현재 안전관리체계 및 설비관리는 양호한 상태이나, 안전성 강화를 위해 제도 및 설비 구조개선이 필요한 실정이다. 이에 따라, 본 논문은 수소에너지 활성화 정책에 의해 수소운송설비 보급·운영의 확대 과정 중 지난 2021년 12월 28일 대전-당진간 고속도로에서 발생한 사고사례를 모사 및 해석을 진행하였으며, 사고 분석 및 해석 결과에 따라 수소운송설비의 안전성 향상 방안에 대해 제언하였다.

• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1742-1756
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• 2023

The hydrogen behavior in a nuclear containment vessel is a significant issue when discussing the potential of hydrogen combustion during a severe accident. After the Fukushima-Daiichi accident in Japan, we have investigated in-depth the hydrogen transport mechanisms by utilizing experimental and numerical approaches. Computational fluid dynamics is a powerful tool for better understanding the transport behavior of gas mixtures, including hydrogen. This paper describes a Large-eddy simulation of gas mixing driven by a high-buoyancy flow. We focused on the interaction behavior of heat and mass transfers driven by the horizontal high-buoyant flow during density stratification. For validation, the experimental data of the Containment InteGral effects Measurement Apparatus (CIGMA) facility were used. With a high-power heater for the gas-injection line in the CIGMA facility, a high-temperature flow of approximately 390 ℃ was injected into the test vessel. By using the CIGMA facility, we can extend the experimental data to the high-temperature region. The phenomenological discussion in this paper helps understand the heat and mass transfer induced by the high-buoyancy flow in the containment vessel during a severe accident.