• Transactions of the Korean hydrogen and new energy society
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• v.34 no.6
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• pp.722-727
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• 2023

There are various types of hydrogen production methods, but among them, the alkaline water electrolysis method produces hydrogen by electrolyzing water, and unlike other methods, it can produce green hydrogen that does not emit pollutants and greenhouse gases. There are many different potential risk factors inherent in the water electrolysis process. So it is necessary to predict an emergency situation in advance and to safely manage and take countermeasures according to the emergency situation. Korea Gas Safety Corporation (KGS) CODE AH271 stipulates legal matters to secure safety, but it is not detalied. Thus it is necessary to take measures to safely control and manage it according to the situation in which an emergency stop is required. In this study, based on KGS CODE and HAZOP for alkaline water electrolysis facilities, factors that can cause emergency situations were derived and countermeasures were prepared.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.663-666
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• 2008

For a fill dam, when a long time has passed since its completion, it is very hard to judge its safety and to maintain effectively it due to limitation and restriction in data showing safety status. Conventional method based on a specific point data by surface settlement gauge is commonly used to define deformation characteristic of dam. However, point data-based deformation analysis cannot provide deformation data of the entire dam. In this study a state-of-the-art terrestrial laser scanning technology is introduced to analyze the entire deformation of dam. As a result, it is known that 3D scanning technique can also be effectively used in evaluating dam safety and then establishing adequate maintain plan.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.55-60
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• 2022

As interest in sustainable and eco-friendly energy sources is increasing due to various problems in the carbon society, a hydrogen economy using hydrogen as a main energy source is emerging. While the natural gas reforming method generates carbon dioxide, the water electrolysis method based on renewable energy is eco-friendly. The water electrolysis device currently being developed uses a 2 Nm³/hr class alkaline aqueous solution as an electrolyte and produces hydrogen based on renewable energy. In this study, risk assessment was conducted for these water electrolysis devices

• Journal of the Korea Safety Management & Science
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• v.25 no.2
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• pp.129-138
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• 2023

This study attempted to analyze the comparative advantage in terms of disaster safety costs in verifying the effectiveness and economic feasibility of the high-performance water-bulwark system in the pole tunnel, which was recently promoted as a part of the acceleration of vehicles. The tunnel to be analyzed was divided into a short tunnel(Anyang, Cheonggye) and a long tunnel(Suraksan, Sapaesan). As a result, it was analyzed that 25% of the improvement effect would occur if one lane was secured by applying the Water-Bulwark System. It was analyzed that this is because the time value cost, which accounts for a large proportion of the traffic congestion cost of short tunnels and pole tunnels, differs depending on the congestion time and traffic volume, not the length of the tunnel.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.7
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• pp.1020-1027
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• 2015

The combined effect of tumbling marination methods (vacuum continuous tumbling marination, CT; vacuum intermittent tumbling marination, IT) and effective tumbling time (4, 6, 8, and 10 h) on the water status and protein properties of prepared pork chops was investigated. Results showed that regardless of tumbling time, CT method significantly decreased the muscle fiber diameter (MD) and significantly increased the total moisture content, product yield, salt soluble proteins (SSP) solubility, immobilized water component (p<0.05) compared with IT method. With the effective tumbling time increased from 4 h to 10 h, the fat content and the MD were significantly decreased (p<0.05), whereas the SSP solubility of prepared pork chops increased firstly and then decreased. Besides, an interactive effect between CT method and effective tumbling time was also observed for the chemical composition and proportion of immobilized water (p<0.05). These results demonstrated that CT method of 8 h was the most beneficial for improving the muscle structure and water distribution status, increasing the water-binding capacity and accelerating the marinade efficiency of pork chops; and thus, it should be chosen as the most optimal treatment method for the processing production of prepared pork chops.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2003.04a
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• pp.255-258
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• 2003

• Nuclear Engineering and Technology
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• v.41 no.8
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• pp.1045-1052
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• 2009

A calculation model is developed to predict the transient free surface flow on the containment floor following a loss-of-coolant accident (LOCA) of pressurized water reactors (PWR) for the use of debris transport evaluation. The model solves the two-dimensional Shallow Water Equation (SWE) using a finite volume method (FVM) with unstructured triangular meshes. The numerical scheme is based on a fully explicit predictor-corrector method to achieve a fast-running capability and numerical accuracy. The Harten-Lax-van Leer (HLL) scheme is used to reserve a shock-capturing capability in determining the convective flux term at the cell interface where the dry-to-wet changing proceeds. An experiment simulating a sudden break of a water reservoir with L-shape open channel is calculated for validation of the present model. It is shown that the present model agrees well with the experiment data, thus it can be justified for the free surface flow with accuracy. From the calculation of flow field over the simplified containment floor of APR1400, the important phenomena of free surface flow including propagations and interactions of waves generated by local water level distribution and reflection with a solid wall are found and the transient flow rates entering the Holdup Volume Tank (HVT) are obtained within a practical computational resource.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.65-75
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• 2018

The wind energy produced at night is being discarded because of the excess power generated at night compared to daytime. To solve this problem, In this study, we analyzed the evaluation contents for evaluation of domestic and overseas water electrolysis systems and drew contents for safety performance contents test of the water electrolysis system based on the evaluation contents. The test contents produced the efficiency measurement test, the hydrogen generated pressure test, and the hydrogen purity test. And the safety performance evaluation of the alkaline water electrolysis system of $5Nm^3/hr$ was performed based on the results. As a result, the hydrogen generation was calculated as $5.10Nm^3/hr$ and the stack efficiency was $4.97kWh/Nm^3$. The purity of the hydrogen generated was 99.993% and it was confirmed that it produced high purity hydrogen. I think will help us assess and build safety performance of water electrolysis systems in the future.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.199-207
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• 2004

Water supply facilities are recently getting larger according as domestic waterworks become multi regional water supply system. Large water supply facilities generally consist of the intake pumping station, water treatment station and water supply & distribution facilities. Although pumping stations and pipeline systems are used to pump up water, it often happens pipeline damage and flooding accident by the water hammer. As a result of this study, a pumping station is guaranteed by the computer simulation and field test analysis. Therefore these are contributed safety operation in pumping station through adjustment of the pumping station safety plan, air valve and valve closing time.

• Structural Engineering and Mechanics
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• v.80 no.5
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• pp.523-538
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• 2021

The mechanical behaviour and stability of coal mining engineering underground is significantly affected by ground water. In this study, nuclear magnetic resonance imaging (NMRI) technique was employed to determine the water distribution characteristics in coal specimens during saturation process, based on which the functional rule for water distribution was proposed. Then, using discrete element method (DEM), an innovative numerical modelling method was developed to simulate water-weakening effect on coal behaviour considering moisture content and water distribution. Three water distribution numerical models, namely surface-wetting model, core-wetting model and uniform-wetting model, were established to explore the water distribution influences. The feasibility and validity of the surface-wetting model were further demonstrated by comparing the simulation results with laboratory results. The investigation reveals that coal mechanical properties are affected by both water saturation coefficient and water distribution condition. For all water distribution models, micro-cracks always initiate and nucleate in the water-rich area and thus lead to distinct macro fracture characteristics. With the increase of water saturation coefficient, the failure of coal tends to be less violent with less cracks and ejected fragments. In addition, the core-wetting specimen is more sensitive to water than specimens with other water distribution models.