• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.477-482
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• 2011

In the present study, the diffusion process of hydrogen leaking from a FCV (Fuel Cell Vehicle) in an underground parking lot was analyzed by numerical simulations in order to assess the risk of a leakage accident. The temporal and spatial changes of the hydrogen concentration as well as the flammable region in the parking lot were predicted numerically. The effects of the leakage flow rate and an additional ventilation fan were investigated to evaluate the ventilation performance in the parking lot to relieve the accumulation of the leaked hydrogen gas. The present numerical analysis can provide useful information such as the distribution of the leaked hydrogen concentration for safety of various hydrogen applications.

• 한국환경보건학회지
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• 제40권1호
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• pp.27-37
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• 2014

Objectives: On September 27, 2012, leakage of anhydrous hydrofluoric acid occurred in a chemical plant in the Gumi National Industrial Complex. Following the accident, local factory workers and residents complained of abnormal health conditions. In addition, visual discolorations were widely observed in crops and trees in surrounding areas. The main objectives of the present study were to identify the area that was affected by the spill using data obtained from plants, soil, and water samples after the accident. Methods: Fluoride concentrations were analyzed in pine tree needles, soil, nearby streams, ponds and reservoirs collected from an area within a radius of three kilometers from the plant where the leak occurred. Fluoride concentrations in the air at the time of leakage were then estimated from fluoride concentrations that were measured in the pine tree needles. A Kriged map was developed to describe the spatial distribution of hydrofluoric acid at the time of the leakage and was compared with the area designated as a Special Disaster Zone by the government. Results: The Special Disaster Zone did not include all the affected area that was estimated by the Kriged map. Analytical results of the environmental samples also supported this discrepancy. Conclusion: Using plants, atmospheric concentrations of fluoride at the time of the leakage could be estimated. For the area that was identified as affected, further public health risk assessment and environmental risk assessment should be considered. Also, in the absence of air monitoring at the time of leakage, studies employing plants may be conducted in order to better understand the spatial extent and severity of the contamination.

• 해양환경안전학회지
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• 제24권6호
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• pp.825-833
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• 2018

본 연구에서는 LNG 공급계통시스템의 재기화 공정에서 배관 손상으로 인한 누출사고 발생시 LNG 성분 및 누출공의 크기에 따른 연소특성에 대한 피해범위를 산출하고, 피해영향을 해석하였다. LNG 성분에 따른 연소특성을 확인하기 위하여 7곳의 LNG 산지별 위험도를 확인한 결과 산지별 큰 차이를 보이지 않았으나, LNG 구성성분 중 메탄의 함유량이 많을수록 플래시화재 발생범위 및 증기운 폭발에 의한 과압이 발생하는 위험범위 그리고 제트화재 발생에 의한 열 복사량 피해영향이 다른 산지에 비해 비교적 낮음을 알 수 있었다. 또한 배관 누출공의 크기에 따라 누설, 파공, 파괴 3단계에 나누어 위험 범위 및 폭발에 미치는 영향에 대한 연구를 수행하였으며, 플래시화재로 인한 피해영향범위를 계산하고, 이에 따라 LNG 누출시 화재가능 위험범위를 확인했으며, 과압의 영향 및 복사열로 부터의 피해범위를 예측할 수 있었다. 이를 통해 LNG 조성 및 배관 누출공의 크기가 화재 및 폭발에 미치는 영향을 예측할 수 있었다.

• 한국안전학회지
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• 제31권5호
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• pp.22-27
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• 2016

The Electrostatic Charge Prevention Technology is a core factor that highly influences the yield of Ultra High Resolution Flat Panel Display and high-integrated semiconductor manufacturing processes. The corona or x-ray ionizations are commonly used in order to eliminate static charges during manufacturing processes. To develop such a revolutionary x-ray ionizer that is free of x-ray radiation and has function to control the volume of ion formation simultaneously is a goal of this research and it absolutely overcomes the current risks of x-ray ionization. Under the International Commission on Radiological Protection, it must have a leakage radiation level that should be lower than a recommended level that is $1{\mu}Sv/hour$. In this research, the new generation of x-ray ionizer can easily control both the volume of ion formation and the leakage radiation level at the same time. In the research, the test constraints were set and the descriptions are as below; First, In order not to leak x-ray radiation while testing, the shielding box was fully installed around the test equipment area. Second, Implement the metallic Ring Electrode along a tube window and applied zero to ${\pm}8kV$ with respect to manage the positive and negative ions formation. Lastly, the ion duty ratio was able to be controlled in different test set-ups along with a free x-ray leakage through the metallic Ring Electrode. In the result of experiment, the maximum x-ray radiation leakage was $0.2{\mu}Sv/h$. These outcome is lower than the ICRP 103 recommended value, which is $1{\mu}Sv/h$. When applying voltage to the metallic ring electrode, the positive decay time was 2.18s at the distance of 300 mm and its slope was 0.272. In addition, the negative decay time was 2.1s at the distance of 300 mm and its slope was 0.262. At the distance of 200 mm, the positive decay time was 2.29s and its slope was 0.286. The negative decay time was 2.35s and its slope was 0.293. At the distance of 100 mm, the positive decay time was 2.71s and its slope was 0.338. The negative decay time was 3.07s and its slope was 0.383. According to these research, the observation was shown that these new concept of ionizer is able to minimize the leakage radiation level and to control the positive and negative ion duty ratio while ionization.

• 한국가스학회지
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• 제9권1호
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• pp.44-50
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• 2005

본 논문에서는 LNG저장탱크의 통압제어 안전관리 시스템에 대한 연구결과를 제시하고 있다. 통합제어 및 안전관리를 효과적으로 진행하기 위한 새로운 통합관리 시스템은 내부탱크로부터 유출되는 가스나 초저온 액체(LNG)에 의한 안전성과 누출문제를 제어하기 위해 온도, 압력, 진동과 같은 신호를 검지하고, 종합적으로 분석하여 시스템의 안전성을 확보할 수 있도록 개발된 것이다. 효율성과 안전성 향상측면에서 LNG저장탱크의 저장용량 증가경향과 최근에 발생된 저장탱크의 고장사례 고찰을 통하여, 기존의 측정장치와 안전장치는 개량되고, 새로운 기술개발이 필요하다는 것을 강조한다. 따라서 본 연구에서는 초대형 LNG저장탱크의 제어와 안전관리를 위해 새로이 개발된 통합제어 안전관리 시스템을 제시하고 있다. 이 시스템에서는 기존의 측정 및 안전장치에 대한 통합과 연계성 및 성능을 향상시키고, 특히 저장탱크 구조물의 변위량을 측정하여 안전성을 확보할 수 있도록 기능성을 새로이 추가하였다. 본 연구에서 개발된 통합제어 안전관리 시스템에 프로세스 통합관리 시스템(PIIS)을 연계하여 사용한다면, LNG 저장탱크의 안전성, 효율성, 생산성은 획기적으로 향상될 것이다.

• 한국산업보건학회지
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• 제23권4호
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• pp.384-392
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• 2013

Objective: This study inspected incident cases, legal control levels, and GHS(Globally Harmonized System of Classification and Labeling of Chemicals) classification results of strong acids such as hydrogen fluoride, hydrogen chloride, nitric acid, and sulfuric acid, which have been responsible for many recent chemical accidents. As a result, it is deemed necessary for legal control levels of these strong acids to be revised and GHS classification be managed nation-wide. Methods: This study inspected incident cases and legal control levels for strong acids such as hydrogen fluoride, hydrogen chloride, nitric acid, and sulfuric acid. The study analyzed and compared chemical information status and GHS classification results. Results: There were 76 domestic incidents involving strongly acidic hazardous materials over the five years between 2007 and 2011. They include 37 leakage incidents(46.7%) within a workplace, 30 leakage incidents(39.5%) during transportation, and nine leakage incidents(13.8%) following an explosion. The strongly acidic materials in question are defined and controlled as toxic chemicals according to the classes of Substances Requiring Preparation for Accidents, Managed Hazardous Substance, Hazardous Chemical(corrosive) as set forth under the Enforcement Decree of the Toxic Chemicals Control Act and Rules on Occupational Safety and Health Standards of Occupational Safety and Health Act. Among them, nitric acid is solely controlled as a class 6 hazardous material, oxidizing liquid, under the Hazardous Chemicals Control Act. The classification results of the EU ECHA(European Chemicals Agency) CLP(Commission Regulation(EC) No. 790/2009 of 10 August 2009, for the purposes of its adaptation to technical and scientific progress, Regulation(EC) No 1272/2008 of the European Parliament and of the Council on classification, labeling and packaging of substances and mixtures) and NIER (National Institute of Environmental Research) are almost identical for the three chemicals, with the exception of sulfuric acid. Much of the classification information of NITE (National Institute of Technology and Evaluation) and KOSHA(Korea Occupational Safety and Health Agency, KOSHA) is the same. NIER provides 12(41.4%) out of 29 classifications, as does KOSHA.

• Nuclear Engineering and Technology
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• 제23권3호
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• pp.299-305
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• 1991

복수기를 통한 해수유입은 증기발생기내에 부식환경을 조성시키게 한다. 이론적 분석을 통하여 복수기누설시에 해수증의 불순물인 염소가 2차계통내에 누적되는 경향을 영광원전을 모델로하여 평가하였다. 분석결과 해수누설시에 고농도의 염소가 증기발생기내에 누적되는 것으로 나타났으나, 이는 증기 발생기내의 수질을 산성분위 기로 조성시킬 것으로 판단되었다. 복수기의 최대허용 설계누설(0.5 gpm)시에는 증기발생기 취출수량을 최대로 늘리고, 복수기정화계통을 가동하더라도 증기발생기에 2.3 ppm 및 복수기집수정에 0.6 ppm의 염소가 누적되는 것으로 나타났다. 또한 증기발생기에서의 염소농축계수는 아래와 같이 전적으로 취출수량 및 정화계통효율에만 의존하는 것으로 나타났으며,（equation omitted）취출수 및 정화계통은 2차계통내의 불순물을 제거하는데 효과적인 것으로 평가되었다.

• Safety and Health at Work
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• 제14권2호
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• pp.237-242
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• 2023

Background: This study evaluated occupational exposure levels of doxorubicin in healthcare workers performing rotational intraperitoneal pressurized aerosol chemotherapy (PIPAC) procedures. Methods: All samples were collected during PIPAC procedures applying doxorubicin to an experimental animal model (pigs). All procedures were applied to seven pigs, each for approximately 44 min. Surface samples (n = 51) were obtained from substances contaminating the PIPAC devices, surrounding objects, and protective equipment. Airborne samples were also collected around the operating table (n = 39). All samples were analyzed using ultra-high performance liquid chromatography-mass spectrometry. Results: Among the surface samples, doxorubicin was detected in only five samples (9.8%) that were directly exposed to antineoplastic drug aerosols in the abdominal cavity originating from PIPAC devices. The telescopes showed concentrations of 0.48-5.44 ng/cm² and the trocar showed 0.98 ng/cm² in the region where the spraying nozzles were inserted. The syringe line connector showed a maximum concentration of 181.07 ng/cm², following a leakage. Contamination was not detected on the surgeons' gloves or shoes. Objects surrounding the operating table, including tables, operating lights, entrance doors, and trocar holders, were found to be uncontaminated. All air samples collected at locations where healthcare workers performed procedures were found to be uncontaminated. Conclusions: Most air and surface samples were uncontaminated or showed very low doxorubicin concentrations during PIPAC procedures. However, there remains a potential for leakage, in which case dermal exposure may occur. Safety protocols related to leakage accidents, selection of appropriate protective equipment, and the use of disposable devices are necessary to prevent occupational exposure.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
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• pp.23-26
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• 2005

LOx와 Kerosene을 연료로 사용하는 LRE(Liquid Rocket Engine) Block에서 지상연소시험을 수행할 경우에 발생하는 위험도를 감소시키는 방법을 연구하였다. 추진제누출로 이어지는 위험한 상황에 대한 원인분석도와 추진제 유출시 사고로 이어지는 발전 양상 및 발전 프로세스, 사고시 손실을 줄이기 위한 기술적인 해결방법을 제시함으로써 기존의 확률적인 통계 값을 바탕으로 하는 것과는 또 다른 방법으로써 위험을 감소하기 위한 대안으로 사용하고자 한다.

• 전기학회논문지
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• 제56권11호
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• pp.1925-1929
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• 2007

This paper is studied on a novel Electric Safety Protection Device (ESPD) of high speed for incapable operation of Earth Leakage Circuit Breaker (ELB) and Molded_case Circuit Breaker (MCCB) using the low voltage distribution line. The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The occurrence factor of the fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Device (RCD), that is ELB and MCCB, of high sensitivity type used at low voltage wiring cuts off earth leakage and overload, but the RCD can't cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied low voltage distribution panel are prescribed to rated breaking time about 30[ms] (KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To be improved on such problem, this research development is proposed to a novel ESPD of high speed to trip of distribution line on electric arc or spark due to electrical fire. Some experimental results of the proposed ESPD are confirmed to the validity of the analytical results.