• Nuclear Engineering and Technology
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• v.34 no.4
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• pp.331-343
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• 2002

We performed an importance analysis of In-Service Testing (157) components for Ulchin Unit 3 using the integrated evaluation method for categorizing component safety significance developed in this study. The developed method is basically aimed at having a PSA expert perform an importance analysis using PSA and its related information. The importance analysis using the developed method is initiated by ranking the component importance using quantitative PSA information. The importance analysis of the IST components not modeled in the PSA is performed through the engineering judgment, based on the expertise of PSA, and the quantitative and qualitative information for the 157 components. The PSA scope for importance analysis includes not only Level 1 and 2 internal PSA but also Level 1 external and shutdown/low power operation PSA. The importance analysis results of valves show that 167 (26.55%) of the 629 IST valves are HSSCs and 462 (73.45%) are LSSCs. Those of pumps also show that 28 (70%)of the 40157 pumps are HSSCs and 12 (30%) are LSSCs.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.6
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• pp.348-355
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• 2017

Human activities have resulted in soil pollution problems to us. Human and ecological risk assessment have been suggested as an efficient environmental management strategy for protecting human and ecosystems from soil pollution. However, Korean environmental policy is currently focused on human protection, and fundamental researches for ecology protection are required for institutional frameworks. In this study, we developed a schematic frame of Korean soil ecological risk assessment, and suggested the basic information for its application. This study suggested a soil ecological risk assessment scheme consisting of 4 steps for derivation of Predicted-No-Effect-Concentration (PNEC): 1) ecotoxicity data collection and reliability determination, 2) data standardization, 3) evaluation of data completeness for PNEC calculation, and 4) determination of ecological-risk. The reliability determination of ecotoxicity data was performed using Reliability Index (RI), and the classification of domestic species, acute/chronic, toxicity endpoint, and soil properties was used for data cataloging. The PNEC calculation methodology was determined as low-reliability, middle-reliability, and high-reliability according to their quantitative and qualitative levels of ecotoxicity data. This study would be the introductory plan research for establishment of Korean soil ecological risk assessment, and it can be a fundamental framework to further develop guidelines of Korean environmental regulation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.27-28
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• 2021

For Barrier-Free certification, the floor and ground surfaces must be finished with materials that are not slippery, flat, and have low-impact in fallis. However, the BF Certification Act does not provide specific methods to meet these regulations. In performance-based design, the responsibility of proving the performance rests with the building owner and architect, so quantitative evaluation indexes are needed to select suitable materials. Furthermore, changes in performance after completion should be checked periodically in 'As-Is' conditions. There are various methods for slips, trips and falls risk assessment, causing confusion for users. In this study, the results of previous studies on the evaluation methods of slips, trips and falls were considered closely, and each quantitative evaluation index that can be used in the new construction and maintenance phase was presented.

• 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.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.110-115
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• 2023

According to the Off-Gas Generation and Use Status Report (2015), Off-gas from the steel industry is estimated to be 80 million tons per year in Korea. If this is purified, large amounts of hydrogen can be produced, so active research and development related to hydrogen purification facilities is underway. In this study, a quantitative risk assessment (QRA) was conducted by analyzing the components of a off-gas based hydrogen purification facility and investigating risk factors. The risk analysis results were determined to be at an acceptable level and will be used as basic data to improve the safety of facilities considering the risks of hydrogen.

• Fire Science and Engineering
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• v.17 no.4
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• pp.20-27
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• 2003

Hazard Analysis is one of the basic tasks to ensure the safety of chemical plants. However, it is an arduous, tedious, time-consuming work and requires multidisciplinary knowledge and demands considerable cognitive load from the analysts. To overcome these problems, there have been attempts to automate this work by utilizing computer technology, particularly in the area of knowledge-based technique. There is two methods in the risk assessment of Chemical plant; quantitative and qualitative risk assessment. Both of them have been applied respectively, but if the integrated method of quantitative and qualitative risk assessments is used, all of the advantage of two methods can be applied. It is difficult to carry out integrated risk management of chemical plant. Therefore, automated integration system of risk management is necessary. We developed S/W Automated System for Hazard Screening & Analysis(ASCA) and applied to practical plant. By applying ASCA to case study, we can get the information about relative ranks of equipments, variable deviation, and consequence of potential accident. In this study, we applied ASCA to the H.T.U(Hydrotreating Unit) of the process to produce aromatic material. We could know relative ranks of equipments, variable deviation of malfunction in storage tank, D-101, and consequence of potential accident using ASCA. If integrated risk management in the chemical plant is applied, we can develop the emergency plan and prevent the accident.

• Journal of ILASS-Korea
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• v.20 no.2
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• pp.101-106
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• 2015

Gas leakage and dispersion in the underground LNG power plant can lead to serious fire and explosion accident. In this study, computational fluid dynamics simulation was applied to model the dynamic process of gas leakage and dispersion phenomena in a closed space. To analyze the risk assessment factor, such as the flammable volume ratio, transient simulations were carried out for different scenarios. The simulation results visualized the gas distribution with time in the closed space. The flammable volume ratio was introduced for quantitative analysis the fire/explosion probability.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.10a
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• pp.135-136
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• 1995

Resent advances in computer technology have introduced a sophisticated capability for computing the biological fate of toxicants in a biological system. This methodology, which has drastically altered risk assessment skill in toxicology, is designed using all the mechanistic information, and all claim better accuracy with extrapolating capability Iron animal to people than conventional pharmacokinetic methods. Biologically based mathematical models in which the specific mechanistic steps governing tissue disposition(pharmacokinetics) and toxic action (pharmacodynamics) of chemicals are constructed in quantitative terms by a set of equations loading to prediction of the outcome of specific toxicological experiments by computer simulation. pharmacokinetic and pharmacodynamic models are useful in risk assessment because their mechanistic biological basis permits the high-to-low dose, route to route and interspecies extrapolation of the tissue disposition and toxic action of chemicals.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.101-106
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• 2009

The unsafe act and unsafe condition is due to human error that experience 80% of safety accidents. Accordingly, one of the most important issues to reduce industrial accidents as a whole, is how to reduce the accident rate by the human error. Therefore, this paper describes the development of quantitative risk assessment (QRA) model by ergonomics for reform of safety consciousness on the semiconductor industry. Unconsciousness, disregard, ignorance, recklessness, and stress among the human factors are selected for conscious reform. Finally, the QRA model is efficiently expected to contribute towards improving continuous self-safety and health and safety culture campaign in order to prevent industrial accidents.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.10a
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• pp.144-153
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• 2006

In order to take TC forecasts from different observatories into consideration, and make quantitative assessment and analysis for avoiding TC routes from the view of safety and cost, a new safe-economic decision making method of TC avoidance routing on ocean was put forward. This model is based on combining forecast of TC trace based on neural networks, technical method to determine the future TC wind and wave fields, technical method of fuzzy information optimization, risk analysis theory, and meteorological-economic decision making theory. It has applied to the simulation of MV Tianlihai's shipping on ocean. The result shows that the model can select the optimum plan from 7 plans, the selected plan is in accordance with the one selected by experienced captains.