• 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.

• 한국가스학회지
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• 제16권6호
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• pp.48-54
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• 2012

최근 LNG 저장탱크 시장에서는 지상식 멤브레인 LNG 저장탱크의 대용량화 용이성, 친환경성, 내부탱크로부터의 낮은 누출 가능성(완만한 누출속도의 증가) 등의 장점으로 동 탱크의 건설에 대한 적극적인 검토가 이루어지고 있다. 이 논문에서는 고장수목분석법(FTA)을 활용하여 기존의 완전방호식 LNG 저장탱크와의 비교 위험성평가를 통해 멤브레인 LNG 저장탱크의 안전성을 분석하였다. 위험성평가 결과는 추가적인 안전장치를 갖지 않는 초기 멤브레인 LNG 저장탱크를 제외하고 두 형식의 LNG 저장탱크가 매우 유사한 위험수준을 가지는 것으로 나타났다.

• 한국안전학회지
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• 제27권4호
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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.

• 한국유체기계학회 논문집
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• 제18권5호
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• pp.13-18
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• 2015

This study has been performed to evaluate the safety of the retainer-type ball valve for a high-pressure pipeline to a district heating plant. The retainer-type ball valve is an improved design for conventional ball valves, such as the floating ball valve and the trunnion ball valve. Numerical analysis of the valve design verification has been applied to investigate the safety factor and seat leakage of the DN300 and DN400 sizes. The given condition to solve the structural analysis was based on the international standard for ISO 5208. In this study, the methods for structural analysis are described in detail. The structural analysis results present the deformations, the equivalent stresses, and the safety factors. Through these results, this study successfully demonstrates the safety and seat leakage of the retainer-type ball valve. They also streamline the process of development for valve manufacturing.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2010년도 춘계학술대회
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• pp.231-237
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• 2010

The purpose of this study was to investigate the actual conditions of radiation safety supervision in animal clinics using quality assurance (QA) and quality control (QC) of diagnostic X-ray units. The surveys for QA/QC, equipment condition, and safety supervision were carried out in 18 animal clinics randomly. The QA/QC included reproducibility of dose exposure, kVp, mAs, collimator accuracy test, collimator luminance test, X-ray view box luminance test, grounding system equipment test and external leakage current test. As a result, 44.44% of reproducibility of dose exposure was proper, 81. 25% of kVp test was good, and 100% of mAs test was appropriate. Also, 66.66% of collimator accuracy test was proper, 61.11% of collimator luminance test was good, 53.13% of X-ray view box luminance test was suitable. In addition, only 5.55% of grounding system equipment and ground resistance was proper, 63.64% of external leakage current test was appropriate in grounding system equipment test.

• 방사성폐기물학회지
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• 제21권4호
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• pp.465-479
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• 2023

To ensure the safety of disposal facilities for radioactive waste, it is essential to quantitatively evaluate the performance of the waste disposal facilities by using safety assessment models. This paper addresses the development of the safety assessment model for the underground silo of Wolseong Low-and Immediate-Level Waste (LILW) disposal facility in Korea. As the simulated result, the nuclides diffused from the waste were kept inside the silo without the leakage of those while the integrity of the concrete is maintained. After the degradation of concrete, radionuclides migrate in the same direction as the groundwater flow by mainly advection mechanism. The release of radionuclides has a positive linear relationship with a half-life in the range of medium half-life. Additionally, the solidified waste form delays and reduces the migration of radionuclides through the interaction between the nuclides and the solidified medium. Herein, the phenomenon of this delay was implemented with the mass transfer coefficient of the flux node at numerical modeling. The solidification effects, which are delaying and reducing the leakage of nuclides, were maintained the integrity of the nuclides. This effect was decreased by increasing the half-life and the mass transfer coefficient of radionuclides.

• 한국가스학회지
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• 제13권2호
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• pp.49-56
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• 2009

본 연구에서는 국내외 LPG 자동차 보급 및 안전관리현황 비교 분석을 통해 국내 LPG 자동차 관련 안전성확보 방향을 제시하였다. 국내 LPG 자동차에 대한 안전관리실태 조사결과 LPG 자동차의 안전성 확보를 위한 제도와 관리실태가 미흡하였고, 실제 약 5천여대의 LPG 자동차에 대한 가스누출 점검결과 약 4% 정도가 누출되고 있음을 확인하였다. 또한 LPG 자동차 관련 안전성향상을 위해 국외에서 운영중인 안전기준을 국내에 적용할 필요성을 확인하였다. 따라서, 국내 LPG 자동차 관련 안전성확보 방향으로 최근 경형승용자동차 등에 대한 LPG 연료사용 허용으로 더욱 위험성이 증대된 지하주차공간에 대한 환기 등 시설기준의 개선, 그리고 LPG 자동차 확인 스티커 부착의무화 등 관리체계 개선방안을 제시하였다.

• 대한안전경영과학회지
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• 제12권4호
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• pp.73-80
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• 2010

The purpose of this study was to investigate the actual conditions of radiation safety supervision in animal clinics using inspection standard of X-ray generator for diagnosis. The surveys for inspection standard system, equipment condition, and safety supervision were carried out in 18 animal clinics randomly. The inspection standard included reproducibility of dose exposure, kVp, mAs, collimator accuracy test, collimator luminance test, X-ray view box luminance test, grounding system equipment test and external leakage current test. The surveys of equipment condition and safety supervision used one-on-one interview with 5 points measurement. As a result, 44.44% of reproducibility of dose exposure was proper, 81.25% of kVp test was good, and 100% of mAs test was appropriate. Also, 66.66% of collimator accuracy test was proper, 61.11% of collimator luminance test was good, 53.13% of X-ray view box luminance test was suitable. In addition, only 5.55% of grounding system equipment and ground resistance was proper, 63.64% of external leakage current test was appropriate in grounding system equipment test. The 100mA electric capacity of X-ray generator for diagnosis was popular with 44.44%, and its 55.56% was purchased used equipment. Monthly average of less than 50 times (61.11%) was top frequency in use, and no animal clinic had a thermo-luminescence dosimeter(TLD). The 16 animal clinics with radiation safety zone and 2 without radiation safety zone were appeared.

• 한국가스학회지
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• 제20권4호
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• pp.25-32
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• 2016

지난 2008년, LPG충전소와 유사한 주유소의 경우 관련법인 위험물관리법 개정을 통해 태양광발전설비의 설치가 합법화 되어 실제 몇몇 주유소에서 태양광발전설비가 운용되고 있다. LPG충전소의 경우 2015년부터 관련법이 개정되어 LPG충전소의 사무실, 캐노피 등의 유휴공간에 태양광발전설비 설치가 합법화 되었다. 일본의 경우 지난 2009년부터 LPG충전시설에 태양광발전설비를 설치하여 운용하고 있는 것이 조사되었다. 위험지역으로 분류되는 LPG충전소의 경우 작은 화재가 큰 사고로 이어질 가능성이 크다. 이에 본 연구에서는 전산유동해석을 통해 태양광발전설비 설치의 안전성에 대해 평가하고자 국내 외의 관련 기준과 사례를 조사하였다. 또한 조사된 결과를 바탕으로 가스유동해석 프로그램의 하나인 FLACS를 이용해 저장탱크 방출관과 자동차용 충전기 파손에 의한 누출을 가정하여 유동해석을 진행하였고, 캐노피에 설치된 태양광발전설비의 안전성에 대해 간접적으로 평가하였다. 그 결과 충분한 안전거리를 확보한다면 캐노피 상단으로의 폭발범위의 LPG가 유입되지 않는 것을 확인할 수 있었다.

• 한국가스학회지
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• 제24권2호
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• pp.29-35
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• 2020

화학사고의 예방 및 대응을 위한 화학물질관리법이 2015년 전부 개정되었다. 이를 계기로 유해화학물질 취급시설의 설치 및 관리기준도 상당히 강화되었다. 하지만, 일부 기존시설의 경우 시설기준 준수가 어려운 쉽지 않은 경우가 발생하지만 일괄적으로 적용되고 있어 산업계에서는 어려움을 호소하고 있는 실정이다. 본 연구에서는 이러한 최근 2년(2017-2018)간 취급시설 중 민원(1,087건)이 가장 많았던(2017:117건, 2018:83건) 방류벽에 대한 선행연구, Flacs 시뮬레이션, 국내·외 기준, 만족도 조사 등을 통해 보다 합리적인 방안을 마련하고자 하였다. 이에 현재 가동 중인 기존시설에 한하여 방류벽의 설치 목적을 고려하여 화학물질 유·누출을 신속하게 감지할 수 있고 신뢰성을 높이기 위해 감지기를 추가로 설치하거나 상시 모니터링이 가능한 폐쇄회로텔레비전(CCTV)을 추가로 설치·운영하는 경우 추가 대체방안으로 인정하였다. 이는 부지를 확보하기 힘들거나, 공사비용 등 경제적인 문제로 법적인 규제를 이행하지 못하는 영세사업장 또는 중소기업의 안전측면과 비용적인 측면에 도움이 될 것이다.