• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.265-275
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• 1993

A vapor explosion has been a concern in nuclear reactor safety due to its potential for a destructive mechanical energy release. In order to properly assess the hazard of a vapor explosion, it is necessary to accurately estimate the conversion efficiency of the thermal energy to mechanical energy. In the absence of a complete model to determine the explosive energy yield, one may have to rely on a simpler upper bound estimate such as a thermodynamic model. This paper discusses various thermodynamic models and presents a clarification of each model in their mathematical formulation and the thermodynamic work conversion. It is shown that the work release in the shock adiabatic model of Board and Hall is essentially equal to that of Hicks-Menzies thermodynamic model. The effect of coolant void fraction on the explosion efficiency is also predicted based on these thermodynamic models. Finally, the Hicks-Menzies model is modified to account for the chemical reaction between a metallic fuel and water and the resultant effects on the explosion expansion work are discussed.

• Journal of the Korean Institute of Gas
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• v.11 no.2 s.35
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• pp.65-70
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• 2007

The explosion phenomenon and hazard estimate of LP gas, the study was examined into variation of oxygen concentration and LP gas concentration. As the result of experiment, the lower explosive limit was decreased as the increased at concentration of LP gas and 21% of oxygen concentration. Minimum oxygen concentration was 14.5%. 12.0%, 11.5% at 1.0, 1.5 and 2.0 bar respectively. And maximum explosion pressure was increased for $6.46kg/cm^2,\;9.41kg/cm^2\;and\;13.49kg/cm^2$ according to increased of pressure. The speed of flame propagation was increased as the higher with initial pressure of LP gas.

• Journal of the Korean Institute of Gas
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• v.25 no.1
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• pp.40-47
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• 2021

In this study, hazards of decomposition and explosion for tert-butylperoxymaleate(TBPM), an organic peroxide, were evaluated by using various equipment to determine the cause of a fire explosion accident. As a result of DSC analysis, the instantaneous power density of TBPM was 26,401 kW/ml, and the NFPA reactive index(Nr) was classified as 4. And the positive value of EP(explosive propagation) and SS(shock sensitivity) showed that the TBPM had a potential hazard of explosion. From the experimental results, the shock sensitivity and friction sensitivity was rated as class 4 and 5, respectively. In the pressure vessel test, TBPM was ranked USA-PVT No.4 and evaluated as a self-reactive substance. In the combustion rate test, TBPM had the combustion rate of 167 mm/sec and was evaluated as the flammable solid classification 2 in GHS.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.70-76
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• 2012

For the safe handling of n-tetradecane, the lower flash points and the upper flash point, fire point, AITs (auto-ignition temperatures) by ignition delay time were experimented. Also lower and upper explosion limits by using measured the lower and upper flash points for n-tetradecane were calculated. The lower flash points of n-tetradecane by using closed-cup tester were measured $104^{\circ}C$ and $112^{\circ}C$. The lower flash points and fire point of n-tetradecane by using open cup tester were measured $113^{\circ}C$ and $115^{\circ}C$, respectively. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 apparatus for n-tetradecane. The experimental AIT of n-tridecane was $207^{\circ}C$. The calculated lower and upper explosion limit by using measured lower $104^{\circ}C$ and upper flash point $140^{\circ}C$ for n-tetradecane were 0.63 Vol.% and 3.18 Vol%.

• Journal of the Korean Institute of Gas
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• v.4 no.3 s.11
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• pp.33-38
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• 2000

When fire and explosion accidents have occurred due to a leak of the flammable gas involving the LNG & LPG in an industrialized society, it is a very important problem. Accordingly, in this paper, we have compared and analyzed the occurrence transition and the electrostatic energy according to dust supplies and pressure variations for the electric charge due to the gas-solids of pipe flow. As the experimental results, if dust amounts and the initial pressure increased, electric charge in the pipe and the exit increased. The Specific charge of $Fe_2O_3$ increased proportionally if the initial pressure increased but if the quantity of dust increased, the specific charge decreased. Energy increased significantly as the dust amounts and the initial pressure increased. The possibility of fire and explosion exist in the measuring point(M 1) and the Faraday cage if natural gas and LPG were used.

• Fire Science and Engineering
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• v.25 no.2
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• pp.120-125
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• 2011

For the safe handling of n-dodecane, the explosion limits were investigated and the lower flash points and AITs (autoignition temperatures) by ignition delay time were experimented. By using the literatures data, the lower and upper explosion limits of n-dodecanee recommended 0.6 Vol.% and 4.7 Vol.%, respectively. The lower flash points of n-dodecane by using closed-cup tester were experimented $77^{\circ}$ and $80^{\circ}C$. The lower flash points of n-dodecane by using open cup tester were experimented $84^{\circ}C$ and $87^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for n-dodecane. The experimental AIT of n-dodecane was $222^{\circ}C$.

• Journal of the Korean Society of Safety
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• v.18 no.3
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• pp.131-140
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• 2003

An accident involving a boiler can result in a disaster since it handles high-pressurized steam so that it may cause an explosion. Therefore, the boiler is very susceptible to industrial accidents. This thesis aimed to develop counter-plans to prevent industrial accidents involved the boiler. At first after collecting accident cases involving boilers, a survey on the trait of them was carried out. Ant on the other hand a qualitative analysis was conducted to draw out hazardous components in the boiler itself and their inherent relative importance was assessed. Through this procedure, 'negligence of unsafe condition' was noted as the major cause for unsafe acts whereas 'fault in work procedure' for unsafe condition. In the meanwhile, results of a hazard analysis using FMEA technique ranked gas safety devices, a switch preventing gas from under-pressurization, protect relays high. In particular, it was pointed out that the water feeding and steam subsystem has more components in hazard than other subsystems. Considering these analyses results, counter-plans to improve safety management was suggested also.

• 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 the Korean Institute of Gas
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• v.26 no.6
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• pp.1-8
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• 2022

With the development of the chemical industry, related accidents frequently occur, and fire and explosion accidents account for a large proportion. In order to prevent fire and explosion accidents, places that handle flammable liquids are classified according to the Korean Industrial Standards (KSC IEC60079-10-1) in accordance with the relevant laws. The same applies to laboratories dealing with flammable liquids. This paper verified the applicability of the procedure for classifying explosion hazard areas according to the Korean Industrial Standards when flammable liquid release from the laboratory to form an evaporative pool, and also verified the effect of a change in ventilation speed on the release characteristics. Through this, it was found that it was difficult to apply the criteria for the classification of places at risk of explosion according to the Korean Industrial Standards, and special safety measures should be prepared.

• Journal of the Korean Society of Safety
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• v.27 no.4
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• pp.20-25
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• 2012

The purpose of this study is to analyze the thermal characteristics and to study fire hazard of electric leakage by iron power accumulated on circuit breaker in an iron processing factory. The thermal characteristics were analyzed while current was applied to the powder for ten minutes. Results showed that temperature of iron powder at 100 mA is $160^{\circ}C$ and at 175mA is $240^{\circ}C$. The sparks have occurred as iron powder drops between two(hot line and neutral line) wires and then iron powder explosion occurred while dropping continuously the iron powder on two lines. Those who work in the iron processing industry need to periodically remove and maintain the iron powder. The thermal characteristics in this paper can be used for electrical fire investigation and for basic data of thermal characteristic of leakage current through iron powder at iron processing factories.