• Journal of the Korean GEO-environmental Society
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• v.21 no.5
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• pp.23-33
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• 2020

As the scale of the economy expands, the number of cases of damage in enclosed spaces such as tunnels is increasing due to the accident of transportation vehicles of dangerous substances such as explosive flammable materials that have increased rapidly. In the case of road tunnels in particular, in the aspect of protection against the long-winding trend and the environment in the downtown area, the number of cases of passing through the downtown area increases, and securing the safety of structures against unexpected extreme disasters such as explosions during tunnel passage is very urgent. For this reason, developed countries are already conducting a review of internal bombardment, but there are almost no evaluation and countermeasures for explosion risk in Korea. Therefore, in this study, in order to evaluate the explosion safety of road tunnels, a boiling liquid explosive explosion (BLEVE), which is considered to have the greatest explosion load among vehicles driving on the road, is set as a reference explosion source, and the equivalent TNT explosion load is used for simulation of the explosion. A method of conversion was presented. In addition, by applying the derived explosion load, dynamic behavior simulation was performed by assuming various variables for the tunnel, and the explosion safety of the tunnel was analyzed.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.407-410
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• 2002

A series of steam explosion experiments using real core materials of $ZrO_2$ and corium(a mixture of $ZrO_{2}\;and\;UO_{2}$) has been performed to evaluate the risk of steam explosion load in nuclear power plants. Surprisingly, spontaneous steam explosions are observed far both materials, which have been thought to be inexplosive so far. The dynamic pressure and morphology of the debris clearly indicate the evidence of an explosion. The experimental results also indicate that $ZrO_2$ is more explosive than corium.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.9
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• pp.1317-1326
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• 2003

The maximum temperature limit at which liquid boils explosively is called the superheat limit of liquids. The superheat limits of hydrocarbon liquids and their mixtures were measured by the droplet explosion technique. Also the fully evaporated droplet at the superheat limit and subsequent bubble evolution from the fully evaporated droplet were visualized. The pressure wave emanating from the evaporating droplet and subsequent bubble evolution process were measured by a piezoelectric transducer.

• Journal of the Korean Magnetics Society
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• v.15 no.5
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• pp.292-297
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• 2005

Steam generator of a nuclear power plant has important rolls for the heat transfer and the isolation of radioactive materials. So bursting of the steam generator tube is directly related to the accident of nuclear power plants. Incone1600 has been used for the steam generator tube material. The material shows non-magnetic and metallic properties, eddy current NDT method has been employed for defects detection. In this work, a differential type of eddy current probe was developed to improve resolution of defect detection. To verify properties of the developed differential type eddy current probe, we have made reference material with SUS304 which has similar magnetic and electrical properties of Inconel600. Using the developed differential type eddy current probe, we can detect defect size of 0.25 mm in diameter and 0.2 mm in depth (volume of $1{\times}10^{-3}\;mm^3$) with the reference material.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.47-59
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• 2024

Purpose: This study aims to propose measures for the prevention of fire and explosion accidents within manufacturing facilities by improving the existing classification criteria for hazardous locations based on the leakage patterns of flammable liquids. The objective is to suggest ways to safely manage ignition sources and combustible materials. Method: The hazardous locations were calculated using "KS C IEC 60079-10-1," and the calculated explosion hazard distances were visualized in 3D. Additionally, the formula for the atmospheric dispersion of flammable vapors, as outlined in "P-91-2023," was utilized to calculate the dispersion rates within the hazardous locations represented in 3D. Result: Visualization of hazardous locations in 3D enabled the identification of blind spots in the floor plan, facilitating immediate recognition of ignition sources within these areas. Furthermore, when calculating the time taken for the Lower Explosive Limit (LEL) to reach within the volumetric space of the hazardous locations represented in 3D, it was found that the risk level did not correspond identically with the explosion hazard distances. Conclusion: Considering the atmospheric dispersion of flammable liquids, it was concluded that safety management should be conducted. Therefore, a method for calculating the concentration values requiring detection and alert based on realistically achievable ventilation rates within the facility is proposed.

• Fire Science and Engineering
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• v.22 no.3
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• pp.228-233
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• 2008

Detonation limit is one of the major physical properties used to determine the fire and explosion hazards of the flammable substances. In this study, the lower detonation limits (LDL) and the upper detonation limits (UDL) of the flammable substances predicted with the appropriate use of the heat of combustion and the stoichiometric coefficient. The values calculated by the proposed equations were a good agreement with literature data within a few percent. From a given results, It is to be hoped that this methodology will contribute to the estimation of the detonation limits of for other flammable substances.

• Journal of the Korean Society of Safety
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• v.13 no.2
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• pp.116-121
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• 1998

Various flammable vapors as energy source and raw material have been stored, transported in the industries, and accidental leakage of these vapors occurs occasionally. Without an appropriate protection system, flammable vapors can be ignited and serious damage results from them. To reduce the risk caused by explosion, we should know the explosion limit and explosion characteristics. In this study, the maximum explosion pressure, the maximum explosion pressure rise, the effect of temperature and mixing with other vapor were measured in a cylindrical vessel. Experimental results showed that maximum explosion pressure of flammable vapor was about 3.1~$4.2 kg/cm^2$ and it was reached 3.4 times faster than that at explosion limit. The lower explosion limit was coincided well with Le Chateilier's equation, however, upper explosion limit was not.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.11a
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• pp.97-102
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• 1997

공정상에서 가연성물질의 생산, 처리, 수송, 저장할 때 취급을 잘못하므로써 화재, 폭발 및 유해물질의 누출을 야기시킬 수 있다. 따라서 가연성물질의 안전한 취급을 위해서는 이들 물질의 중요한 기초적인 안전특성(safety property) 자료인 인화점(flash point)에 대한 지식을 필요로 하고 있다. 인화점은 가연성 액체의 화재 위험성을 나타내는 지표로써, 가연성액체의 액면 가까이서 인화할 때 필요한 증기를 발산하는 액체의 최저온도로 정의한다. 인화점에는 하부인화점과 상부인화점으로 나누고 있으며, 일반적으로 하부인화점을 인화점이라 한다. (중략)

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.462-467
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• 2003

Organic solvent를 원료로 한 액상 세척제는 가전제품, 컴퓨터용품, 전기기구 세척등의 민수 용품과 산업용 정밀 기계부품과 같은 대상물 세척 등에 사용되고 있다. 그러나 일반 유기용제를 주성분으로 한 유기용제형 세척제의 경우 장기 오염물질에 따른 세척력 저하, 공정상 VOC(Volatile Organic Compound)가 과도 발생할 뿐만 아니라 비생분해성, 높은 증기압, 화재 및 폭발 위험성, 냄새 성분 발생 등 안전 및 보건상 치명적인 결함이 있다.(중략)

• Journal of the Korea Safety Management & Science
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• v.4 no.3
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• pp.35-43
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• 2002

For the unconfined vapor cloud explosion accident by the continuous release of gas-liquid flow of various saturated liquids in a vessel at ground level, overpressures were estimated and analyzed with various release conditions and materials by TNT equivalency model with vapor dispersion. We found that at same release conditions, overpressure showed n-heptane > xylene > n-hexane > toluene > n-heptane > benzene, respectively and that overpressure was increased with increasing the hole diameter and the storage pressure, but it was increased with decreasing the wind speed, the interested distance, and the vessel thickness.