• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.35-41
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• 2018

Chemical accidents generated during maintenance, repair, and normal operation, such as dispersion, fire, and explosions, can cause massive losses like a 2012 hydro fluorine leak in Gumi, South Korea. Since this accident, many researches have studied physical mitigation systems. However, due to the lack of potential costs and time, it is really hard for many companies to install mitigation systems without prior knowledge. Thus, the efficacy of mitigation system should be evaluated. This study assesses a dike design considering the fluid velocity at an open hole when a leakage accident occurs. It is assumed that leakage materials follow a free fall motion. Throughout case studies, a current KOSHA guide for a dike design was evaluated and new guidelines handling various conditions were proposed.

• Nuclear Engineering and Technology
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• v.37 no.6
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• pp.537-556
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• 2005

A primary-pipe rupture accident is one of the design-basis accidents of a High-Temperature Gas-cooled Reactor (HTGR). When the primary-pipe rupture accident occurs, air is expected to enter the reactor core from the breach and oxidize in-core graphite structures. This paper describes an experiment and analysis of the air ingress phenomena and the method fur the prevention of air ingress into the reactor during the primary-pipe rupture accident. The numerical results are in good agreement with the experimental ones regarding the density of the gas mixture, the concentration of each gas species produced by the graphite oxidation reaction and the onset time of the natural circulation of air. A hydrogen production system connected to the High-Temperature Engineering Test Reactor (HTTR) Is being designed to be able to produce hydrogen by themo-chemical iodine-Sulfur process, using a nuclear heat of 10 MW supplied by the HTTR. The HTTR hydrogen production system is first connected to a nuclear reactor in the world; hence a permeation test of hydrogen isotopes through heat exchanger is carried out to obtain detailed data for safety review and development of analytical codes. This paper also describes an overview of the hydrogen permeation test and permeability of hydrogen and deuterium of Hastelloy XR.

• Journal of the Korean Institute of Gas
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• v.17 no.4
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• pp.26-32
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• 2013

The best way to prevent major occupational accidents is prohibiting use of hazardous substances such as flammable gas, toxic gas whereas using alternative substances that ensured safety. but if there are no economic efficiency and substituting technologies of alternative substances, the best way is preparing to prevent accidents thoroughly. Therefore, this study has developed and selected release scenarios to use and apply for consequence analysis and emergency action plan for HF charging process of chemical plants that have HF release accidents and high probability of release accidents.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.323-330
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• 2022

Safety accidents in university laboratories are constantly occurring due to various chemical, physical, and biohazard risk factors. In this study, the trend of accident occurrence and correlations between factors were derived through statistical and cross-analysis of 192 accident cases in university labs between 2016 and 2020. Directions and strategies were prepared from the correlations of major factors, and guidelines for improvement of the laboratory safety management system were suggested by comparing and analyzing existing policy directions for laboratory accidents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.60-66
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• 2020

This paper presents a method for improving the selection of boundary areas suitable for Korea's situation based on domestic and foreign case studies on the establishment of boundary areas to protect people and the environment from chemical substances in response to chemical accidents and chemical terrorism. Currently, various related ministries are divided into hot zones, warm zones, and cold zones in common, but in specific areas, they are used in different ways in terms of terminology utilization. Therefore, it was suggested that the boundary areas be divided into four zones: hot zone, warm zone, cold zone, and safety zone. In addition, the terms warm zone and safety zone should be re-established. The existing ERPG acute exposure standard does not take into account various exposure times. Therefore, it is unsuitable for long-term exposure, so the priority of application should be AEGL, ERPG, PAC, and IDLHs. The CARIS information provision method is classified into substances that can or cannot be diffused or classified as indoor leaks. In addition, the wind direction trust line and the ERG's initial separation distance and protective action distance are expressed together so that they can be used for accident responses.

• Fire Science and Engineering
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• v.33 no.3
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• pp.63-73
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• 2019

This study examined the activity of the simulated training scenarios and special rescue crew assuming a chemical accident inside the building. To improve the response ability and safety of rescue personnel in the event of a chemical accident, a total of eight stages of simulated training scenarios were conducted and the activity was measured. As a result of the activity measurement according to the simulation training scenario, the average maximum heart rate of the rescuers was the highest at 177.50 ppm in the 4^th stage, and then 176.67 ppm for the 5^th step, 171.17 ppm for the 2^nd step, 169.33 ppm for the 3^rd step, 162.17 ppm for the 6^th step, 159.58 ppm for the 7^th step, 148.75 ppm for the 8^th step, and 139.33 ppm for the 1^st step. The mean maximum respiratory rate was the highest at 38.17 rpm in the 4^th stage, followed by 37.58 rpm in the 5^th stage, 32.00 rpm in the 6^th stage, 31.58 ppm in the 7^th stage, 31.33 rpm in the 3^rd stage, 31.08 rpm in the 2^nd stage, and 28.00 rpm in the 8^th stage. The 1^st stage was 22.67 rpm. In addition, body water reduction measurements were reduced by up to 0.7 g due to the training intensity.

• 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 the Korean Institute of Gas
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• v.27 no.4
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• pp.12-18
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• 2023

The effective evacuation strategy according to the accident scenario is crucial to minimize human casualties in the event of toxic gas leak accidents. In this study, the effect of the direction of a building and the location of an industrial complex on the increase in indoor concentration and outdoor diffusion was examined under the same leakage conditions, and effective evacuation criteria were established. In addition, the guidelines for building directions were suggested when constructing buildings that would mitigate human damage caused by chemical accidents. Three scenarios where buildings faced the front, side, and rear of the leakage direction were investigated through CFD simulations. The results revealed that when the building faced the industrial complex, both indoor and outdoor average gas concentrations increased significantly, reaching up to 120 times higher than the other two orientations. Moreover, the indoor space was filled with toxic gas substances more than twice in the same time due to the rapid increase of indoor concentration rate. In cases where the building's windows were positioned at the front, toxic gas stagnation occurred around the building due to pressure differences and reduced flow velocities. Based on our findings, the implementation of these guidelines will contribute to safeguarding residents by minimizing exposure to toxic gas during chemical accidents.

• Journal of the Korea Safety Management & Science
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• v.9 no.3
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• pp.21-27
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• 2007

This paper analyses the effect of parameters on the consequences of the unconfined vapor cloud explosion accident (UVCE) by the release of heavy gas (xylene vapor). Simulation results showed that the overpresure was increased with the increase of the release hole diameter and with the decrease of the interested distance and the wind speed. While, the overpresure was not nearly affected by the release height, weather and environmental conditions. From the results of the consequence analysis and analysis of affecting the consequences of UVCE, the emergency plan should be established taking into account these parameters.

• Nuclear Engineering and Technology
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• v.52 no.8
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• pp.1638-1649
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• 2020

In the case of a severe accident in a Light Water Reactor, the issue of late release of fission products, from the primary circuit surfaces is of particular concern due to the direct impact on the source term. CsI is the main iodine compound present in the primary circuit and can be deposited as particles or condensed species. Its chemistry can be affected by the presence of molybdenum, and can lead to the formation of gaseous iodine. The present work studied chemical reactions on the surfaces involving gaseous iodine release. CsI and MoO₃ were used to highlight the effects of carrier gas composition and oxygen partial pressure on the reactions. The results revealed a noticeable effect of the presence of molybdenum on the formation of gaseous iodine, mainly identified as molecular iodine. In addition, the oxygen partial pressure prevailing in the studied conditions was an influential parameter in the reaction.