• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.4
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• pp.1-10
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• 2013

This paper addresses the derivation of 6-DOF equation of Tanker and Receiver's aircraft for aerial refueling. The new set of nonlinear equations are derived in terms of the relative translational and rotational motion of receiver aircraft respect to the tanker aircraft body frame. Further the wind effect terms due to the tanker's turbulence are included. The derivation of absolute dynamic equation for tanker aircraft written in the inertial frame is calculated from the relative dynamics equations of receiver. The derived relative and absolute equations are implemented the simulation in the same flight conditions to verify the relative motion and compare the trim results by using the MATLAB/SIMULINK program.

• Nuclear Engineering and Technology
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• v.36 no.6
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• pp.497-511
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• 2004

A PSV (pressurizer safety valve) popping test carried out in the early phases of a refueling outage may trigger a test-induced LOCA(loss of coolant accident) if a PSV fails to fully close and is stuck in a partially open position. According to a KSNP (Korea standard nuclear power plant) low power and shutdown PSA (probabilistic safety assessment), the failure of a high pressure safety injection (HPSI) accompanied by the failure of a PSV to fully close was identified as a dominant accident sequence with a significant impact on low power and shutdown risks (LPSR). In this study, we aim to investigate and verify a new means for mitigating this type of accident using a thermal-hydraulic analysis. In particular, we explore the applicability of an aggressive cool-down combined with operator actions. The results of the various sensitivity studies performed there will help reduce LPSR and improve Refueling outage safety.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.3
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• pp.240-246
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• 2022

This study was conducted to develop a domestic product for a flow control valve for a hydrogen refueling station, and a domestic prototype was manufactured and the durability performance evaluation was conducted through comparison with an imported products. The stress generated by the internal pressure was checked and safety was confirmed using a commercial structural analysis program, ABAQUS, in accordance with the withstand pressure test standards. In addition, after identifying the weak areas the fatigue life was predicted through a commercial software, fe-safe. This fatigue analysis showed that the hydrogen gas repeated test criteria were satisfied.

• Journal of the Korean Professional Engineers Association
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• v.34 no.3
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• pp.28-32
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• 2001

Using the CNG(compressed natural gas) and LPG(liquified petroleum gas) as the automotive fuel will be expanded because of their clean effect to the environmental air qualify. But these programs of gas using expansion would have a difficulty due to public consideration of gas utilities as a big hazard. The Ministry of Environment has an ambitious plan to substitute more than 25,000 buses with CNG and ensure more than 200 CNG refueling stations as well by the year of 2007. However, it is very difficult to establish new CNG and LPG refueling stations because of expanded safety distance than ever before by several major explosion accidents.

• Journal of Energy Engineering
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• v.28 no.4
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• pp.48-60
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• 2019

After the Paris Agreement in 2015, the government has been promoting various policies such as 'Hydrogen-Economy Roadmap(2019)' to supply hydrogen. As part of this, the government announced the goal of building 310 hydrogen refueling stations(HRS) until 2022. To this end, special case standard for the introduction of complex, packaged, and mobile hydrogen refueling stations(MHRS) have been enacted and promulgated. The MHRS has the advantage of being able to supply hydrogen to multiple regions. However, due to the movement and close distance between facilities, it is necessary to secure proper installation standards and operational safety through safety analysis. In this study, the possibility of introduction was investigated by designing a standard model and quantitative risk assessment(QRA). As a result of QRA, personal and social risk were acceptable, and the empirical test direction and implications were derived.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.5
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• pp.515-524
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• 2022

In this study, the on-site hydrogen production process for refueling stations that were not energy-optimized was improved through exergy analysis and heat exchange network synthesis. Furthermore, the process was scaled up from 30 Nm3/h to 150 Nm3/h to improve hydrogen production capacity. Exergy analysis results show that exergy destruction in the SMR reactor and the heat exchanger accounts for 58.1 and 19.8%, respectively. Thus, the process is improved by modifying the heat exchange network to reduce the exergy loss in these units. As a result of the process simulation analysis, thermal and exergy efficiency is improved from 75.7 to 78.6% and 68.1 to 70.4%, respectively. In conclusion, it is expected to improve the process efficiency when installing on-site hydrogen refueling stations.

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.551-557
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• 2024

Hydrogen is a renewable energy source with various characteristics such as clean, carbon-free and high-energy, and is internationally recognized as a "future energy". With the rapid development of the hydrogen energy industry, more hydrogen infrastructure is needed to meet the demand for hydrogen. However, hydrogen infrastructure accidents have been occurring frequently, hindering the development of the hydrogen industry. HyRAM+, developed by Sandia National Laboratories, is a software toolkit that integrates data and methods related to hydrogen safety assessments for various storage applications, including hydrogen refueling stations. HyRAM+'s physics mode simulates hydrogen leak results depending on the hydrogen refueling station components, graphing gas plume dispersion, jet frame temperature and trajectory, and radiative heat flux. In this paper, hydrogen leakage data was extracted from a hydrogen refueling station in Samcheok, Gangwon-do, using HyRAM+ software. A hydrogen leakage simulator was developed using data extracted from HyRAM+. It was implemented as a dashboard that shows the data generated by the simulator using a database and Grafana.

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.85-99
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• 2024

As the proliferation of hydrogen electric vehicles accelerates, there is observed diversification in hydrogen refueling station models. This diversification raises safety concerns for different types of stations. This study conducted a quantitative risk assessment of a multi-vehicle hydrogen station, capable of simultaneously refueling cars, buses, and trucks. Utilizing Gexcon's Effects&Riskcurves Software, scenarios of fire and explosion due to hydrogen leaks were assessed. The study calculated the impact distances from radiative heat and explosion overpressure, and measured risks to nearby buildings and populations. The largest impact distance was from fires and explosions at dispensers and high-pressure storage units. High-pressure storage contributes most significantly to personal and societal risk. The study suggests that conservative safety distances and proper protective measures for these facilities can minimize human and material damage in the event of a hydrogen leak.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.1
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• pp.32-40
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• 2018

There has been an measuring errors between state of charge (SOC; kg) value and mass flow meter (MFM) value in dispenser for hydrogen refueling station. Finally, we observed average 15.5% weight difference between these two values and the MFM readings show a 15.5% higher readout of the SOC readings. Each car was charged with average 2.66 kg of hydrogen fuel during this period. In the initial charging of the day shows less measuring value than the final charging with the maximum 0.038 kg times number of filling. There is no effects of atmosphere temperature change for the hydrogen filled weight during one full year such as January's cold winters and August's hot summers.

• Journal of Environmental Science International
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• v.4 no.5
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• pp.61-61
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• 1995

Volatile organic compounds(VOCs) are of concern for their potential chronic toxicity, their suspected role in the formation of smog, and their suspected role in destruction of stratospheric ozone. Present study evaluated the exposures to selected VOCs in three microenvironments: 2 chlorinated and 5 aromatic VOCs in the indoor and outdoor air, and 5 aromatic VOCs in the breathing zone air of gas-service station attendants. With permissible Quality Assurance and Quality Control performances VOC concentrations were measured 1) to be higher in indoor air than in outdoor air, 2) to be higher in two Taegu residential areas than in a residential area of Hayang, and 3) to be higher in the nighttime than in the daytime. Among five aromatics, Benzene and Toluene were two most highly measured VOCs in breathing zone air of service station attendants. Based on the sum of VOC concentrations, the VOC exposure during refueling was estimated to be about 10% of indoor and outdoor exposures. For Benzene only, the exposure during refueling was estimated to cause about 52% of indoor and outdoor exposure. The time used to calculate the exposures was 2 minutes for refueling and 24 hours for indoor and outdoor exposures.