• Journal of the Korea Safety Management & Science
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• v.7 no.4
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• pp.85-99
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• 2005

The main objective of this paper is to search whether containment vessel's best pressure may increase until how long when loss of coolant accident (LOCA) happened in containment vessel of Ulchin nuclear power plant 1 and 2. Another goal of this research is to find the influential factors that increase containment vessel pressure. Model for this research is Ulchin nuclear power plant 1 with 10 cycles. Data were collected by simulator of Ulchin nuclear power plant 1 and design of experiment was used for data analysis. For the experiment, seven factors that are going to influence in containment vessel pressure were chosen. It was found that fatter which influences in early rise of containment vessel pressure after LOCA is only explosion size. Also, containment vessel's best pressure (3.74 bar.a) was much lower than limit (4.86 bar.a) of FSAR (Final Safety Analysis Report).

• Journal of the Korean Society of Safety
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• v.38 no.1
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• pp.70-77
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• 2023

Gas has replaced coal or petroleum as primary fuel because of its convenience. However, gas has risk of fire, explosion, or poisoning. To reduce gas-related accidents, many strategic projects have been being carried based on 'Gas Safety Management Basic Plans' on a domestic scale. In spite of those projects, the gas-related accident rate did not decrease over past decades. Thus, this study was conducted to analyze the effectiveness of ongoing projects, and to find out ways to make improvements. Conventional statistical analyses on accident data published by gas-related institutions were not useful to determine meaningful attributes to predict future. Whereas, accident case analyses adopted in the present study discovered differences in the type of people and their unsafe acts for each gas type. Meanwhile, the overall average priority of projects was not high in the aspect of System Safety Precedence. If the current trend is maintained, with sigmoid functions, it can be estimated that mean annual accident rate will decrease by only 2.0% in the next two decades. To improve the current trend, the present study made conclusions as followings: (1) safety projects should be designed with careful consideration of accident traits including gas type, unsafe acts, and persons involved and (2) alternative strategies should include system considerations such as minimum hazard design and safety devices prior to mere education or training. To summarize briefly, the present state related with gas accidents highlights the necessity of a system-based multidisciplinary approach.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.10-21
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• 2014

In Fukushima accident, when the severe accident such as a natural disaster happens, it is impossible to monitor the plant status due to a extreme environment and station blackout and most I&C systems break downs. Finally, these cause the loss of emergency cooling function and thus results in a hydrogen explosion and radiation leak. In this paper, the emergency response system is introduced that monitors and controls properly when the sever accidents like Fukushima accident happen, And the performance requirements of a wireless communication system used in the emergency respons system is described and the performance of emergency communication system is analyzed using the markov model.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3264-3274
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• 2021

In a severe accident of light water reactor (LWR), molten core material (corium) can be released into the wet cavity, and a fuel-coolant interaction (FCI) can occur. The molten jet with high speed is broken and fragmented into small debris, which may cause a steam explosion or a molten core concrete interaction (MCCI). Since the premixing stage where the jet breakup occurs has a large impact on the severe accident progression, the understanding and evaluation of the jet breakup phenomenon are highly important. Therefore, in this study, the jet breakup simulations were performed using the Smoothed Particle Hydrodynamics (SPH) method which is a particle-based Lagrangian numerical method. For the multi-fluid system, the normalized density approach and improved surface tension model (CSF) were applied to the in-house SPH code (single GPU-based SOPHIA code) to improve the calculation accuracy at the interface of fluids. The jet breakup simulations were conducted in two cases: (1) jet breakup without structures, and (2) jet breakup with structures (control rod guide tubes). The penetration depth of the jet and jet breakup length were compared with those of the reference experiments, and these SPH simulation results are qualitatively and quantitatively consistent with the experiments.

• Fire Science and Engineering
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• v.31 no.1
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• pp.18-25
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• 2017

Each country tries to prevent major industrial accidents at industrial sites, such as fire and explosion as well as poisoning incidents, and regulation of the management of chemicals is being enhanced in all sectors. In particular, in the case of laboratories, a variety of chemicals have been developed and handled in accordance with the development of science and technology. On the other hand, the accident probability at laboratories is higher than at industrial sites, because many different kinds of chemicals are handled in the laboratory but in very small amounts and chemical, physical, and biological studies have been carried out in limited spaces. Recently, the accident probability at laboratories was found to be higher as convergence/integration studies were carried out beyond the academic arena. Therefore, in this study, a survey of chemical management was conducted to prevent accidents due to chemicals targeting the laboratory safety coordinator using the FGI (focus group interview) method. The building plan of a chemical management system was suggested based on the results of the survey.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.750-754
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• 2014

Quantitative risk analysis has been performed for a pervaporation process for production of high test peroxide. Potential main accidents are explosion and fire caused by a decomposition reaction. As the target process has a laboratory scale, the consequence is considered to belong to Category 3. An event tree has been developed as a model for occurrence of a decomposition reaction in the target process. The probability functions of the accident causes have been established based on the frequency data of similar events. Using the constructed model, the failure rate has been calculated. The result indicates that additional safety devices are required in order to achieve an acceptable risk level, i.e. an accident frequency less than $10^{-4}/yr$. Therefore, a layer of protection analysis has been applied. As a result, it is suggested to introduce inherently safer design to avoid catalytic reaction, a safety instrumented function to prevent overheating, and a relief system that prevents explosion even if a decomposition reaction occurs. The proposed method is expected to contribute to developing safety management systems for various chemical processes including concentration of hydrogen peroxide.

• Journal of the Korean Institute of Gas
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• v.18 no.3
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• pp.67-74
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• 2014

Buried natural gas pipelines in densely populated urban areas have serious hazards of property damages and casualties generated by release, dispersion, fire and explosion of gas caused by outside or inside failures. So as to prevent any accident in advance, managers implement danger management based on quantitative risk analysis. In order to evaluate quantitative risk about buried natural gas pipelines, we need calculation for radiant heat and pressure wave caused by calculation for release rate of chemical material, dispersion analysis, fire or explosion modeling through consequence analysis in priority, in this paper, we carry out calculation for release rate of pressured natural gas, radiant heat of fireball based in accident scenario of actual "San Bruno" buried high pressured pipelines through models which CCPS, TNO provide and compare with an actual damage result.

• Journal of the Korean Institute of Gas
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• v.13 no.1
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• pp.61-67
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• 2009

There are lots of energy facilities using gas(storage facility, compressed gas pipe, station, tank lorry) on the domestic. These major gas facilities cause major accidents associated with fire, explosion, toxic and etc. With the increased interest in reducing air pollution, supply of natural gas for gas vehicles is increasing. Thus, the number of establishments of LNG (Liquefied Natural Gas) and CNG(Compressed Natural Gas) stations is increasing as well. However, due to major gas accidents such as the fire and explosion accident of a Buchen LPG (Liquefied Petroleum Gas) station, it is difficult to establish a new station. In this research, we present quantitative risk assessment for LCNG;LNG multi-station and compare it result against individual risk criteria of HSE.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.180-185
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• 2021

In accordance with the revision of the US-Korea missile guidelines, restrictions on the use of solid propellants for space launch vehicles have been completely lifted. The solid propellant can be used as a solid propellant rocket like the KSR-1 (Korea Sounding Rocket-1), and can also be used as a thrust augmentation booster for liquid fuel launch vehicles. It is known that solid propellants have a lower risk of explosion than liquid propellants. but if an accident such as an explosion at the Alcantara Launch Center in Brazil occurs, it can lead to a large-scale personal accident. In order to prevent such large-scale accidents, it is necessary to review and reflect the minimum safety distance during use, storage and combustion test of solid propellants from the planning phase of the project. In this paper, the minimum safety distance for safe use of the solid propellant is presented by dividing it into storage facilities and combustion tests.

• Fire Science and Engineering
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• v.30 no.6
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• pp.48-56
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• 2016

A crude oil leakage from a large atmospheric storage tank occurred on 4 April 2014 at 14:50 in Ulsan City, while storing the crude oil in the tank. Emergency Rescue Control Group was deployed in the scene. The company, Fire Service Headquarters and associated agencies got together in Command Post (CP) for discussing an effective corresponding strategy. Many solution plans were drafted in the debate such as power down, stopping the facilities, checking the density of inflammable gas, suppressing oil evaporation, moving the leaked crude oil to a nearby tank and a processing plant and avoiding marine pollution. All the solutions were carried out in cooperation with several agencies and partners. The oil leakage accident was successfully settled up within the process of responding, The Fire Service Headquarters and the company thought that the most important thing was the suppression of oil evaporation and the elimination of ignition source. With Fire Service Headquarters and several agencies' every effort, an explosion and a fire didn't occurred in the scene. This study suggest the improvement of the operating system in Emergency Rescue Control Group in case of petroleum leakage, explosion and fire accidents of atmospheric storage tank, different from a ordinary disaster. Assuming that petroleum leakage in atmospheric storage tank develop the explosion and fire accidents, the spreading speed of the flame and the burning time was experimented and compared with each other. Furthermore, this study concentrates on the effective field response plan prepared for the afterward explosion and fire accidents from petroleum leak in a storage tank, with the database experimented and analyzed in accordance with the angle of radiation in the foam nozzle and the pressure of pumping in a fire engine.