• 한국가스학회지
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• 제8권4호
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• pp.8-14
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• 2004

독성가스의 누출은 공정설비의 위험도에 크게 영향을 미친다. 본 연구에서는 API-581에 의한 위험기반검사에서 매개변수의 변화에 따른 독성가스(암모니아 및 염소 가스)의 누출사고 결과를 분석하였다. 그 결과, 독성물질의 누출에 의한 사고결과, 즉 독성 피해영역은 온도가 증가할수록, 그리고 압력과 파이프 직경이 감소할수록 감소하였으며, 동일한 누출조건에서 암모니아 보다 염소가스인 경우에 큰 값을 나타내었다.

• 한국안전학회지
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• 제26권5호
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• pp.105-109
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• 2011

Since a severe accident, which happens in low frequency, can cause serious damages, the interests in off-site consequence analysis for a nuclear power plant have been increased after Chernobyl, TMI and Fukushima accidents. Consequences, which are the effects on health and environment caused by released radioisotopes, are evaluated using MACCS II code based on the method of Level 3 PSA. To perform a consequence analysis for the reference plants, the input data of the code were generated such as meteorological data, population distribution, release fractions, and so on. Using these input data, acute and lifetime dose as an organ, CCDF for early fatalities and latent cancer fatalities, and average individual risk were analyzed by using MACCS II code in this study. These results might contribute to establishing accident management plan and quantitative health object.

• 대한안전경영과학회지
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• 제11권4호
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• pp.201-211
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• 2009

The types and quantities of Hazmat and Hazmat transportation are gradually increasing, keeping pace with industrialization and urbanization. At present the safety management for Hazmat transportation only considers reducing accident probability, but even when an accident involving Hazmat-carrying vehicles occurs, that is not regarded as a Hazmat-related accident if the Hazmats do not leak out from the containers carrying them. Thus the methods to reduce risk (Risk=Probability$\times$Consequence) have to be developed by incorporating accident probability and consequence. By using Geographic Information System (GIS), a technical method is invented and is automatically able to evaluate the consequence by different types of Hazmat. Thus this study analyzed the degree of risk on the links classified by the Hazmat transport pathways. In order to mitigate the degree of risk, a method of 7-step risk management on Hazmat transportation in railway industries can be suggested. (1st step: building up GIS DB, 2nd step: calculating accident probability on each link, 3rd step: calculating consequence by Hazmat types, 4th step: determination of risk, 5th step: analysis of alternative plans for mitigating the risk, 6th: measure of effectiveness against each alternative, and 7th step: action plans to be weak probability and consequence by the range recommended from ALARP). In conclusion, those 7 steps are used as a standardization method of optimum transportation routing. And to increase the efficiency of optimum transportation routing, optional route can be revise by verification.

• Journal of Radiation Protection and Research
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• 제28권3호
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• pp.189-197
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• 2003

Level 3 PSA(사고결말분석)는 원자력 발전소의 사고 시 누출된 방사성 핵종으로 인해 야기되는 환경 및 인체에 미치는 영향(공중위험도)을 평가하는 것이다. 본 논문에서는 원자력 발전소의 중대사고시 환경으로 방출되는 방사성물질의 방출특성과 그 결과로 인체에 미치는 영향에 대하여 확률론적 사고영향분석코드인 MACCS를 이용하여 평가하였다. 이러한 평가는 관련 변수들의 상대적 중요도를 파악하는데 유용할 뿐만 아니라 소외리스크(Offsite Risk)를 최소화시키기 위한 대책개발에 있어 중요한 지표가 될 수 있다. 특히 방출고도, 열 함량, 방출기간의 3가지 중요 변수를 선정하여, 이들 변수들의 변화에 따라 영향을 받는 조기사망자 수와 암 사망자 수의 변화를 분석하였다. 또한, 참조원전의 위험성 평가를 위하여 IPE(Individual Plant Examination)에서 제시된 STC(Source Term Category) 19가지 시나리오에 대한 각 사고별 빈도와 MACCS코드를 수행한 결과값을 이용하여 참조원전의 위험성 평가를 수행하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1365-1375
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• 2009

The types and quantities of Hazmat and Hazmat transport are gradually increasing, keeping pace with industrialization and urbanization. There are currently more than 1,000 types of Hazmat,, and new types are added every year. At present the safety management for Hazmat transport only considers reducing accident probability, but even when an accident involving Hazmat-carrying vehicles occurs, that is not regarded as a Hazmat-related accident if the Hazmats do not leak out from the containers carrying them. Based on this principle, in turn., the methods to reduce risk (Risk=Probability$\times$Consequence) have to be developed by incorporating accident probability and consequence. By using Geographic Information System (GIS), a technical method was invented and is automatically able to evaluate the consequence by different types of Hazmat. Thus this study analyzed the degree of risk on the links classified by the Hazmat transport pathways. In order to mitigate the degree of risk, a method of 7-step risk management in transporting Hazmat on railway industries was suggested. The 7-step risk management is definded as the following: 1st step: buliding up GIS DB, 2nd step: calculating accident probability on each link, 3rd step: calculating consequence by Hazmat types, 4th step: determination of risk, 5th step: analysis of alternative plans for mitigating the risk, 6th: measure of effectiveness against each alternative, and 7th step: action plans to be weak probability and consequence by the range recommended from ALARP. In conclusion., those 7 steps are recommended as a standardization method in this study.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.368-372
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• 2016

Background: Methodologies for a series of radiological consequence assessments show a distinctive difference according to the design principles of the original nuclear suppliers and their technical standards to be imposed. This is due to the uncertainties of the accidental source term, radionuclide behavior in the environment, and subsequent radiological dose. Both types of PWR and PHWR are operated in Korea. However, technical standards for evaluating atmospheric dispersion have been enacted based on the U.S. NRC's positions regardless of the reactor types. For this reason, it might cause a controversy between the licensor and licensee of a nuclear power plant. Materials and Methods: It was modelled under the framework of the NRC Regulatory Guide 1.145 for light-water reactors, reflecting the features of heavy-water reactors as specified in the Canadian National Standard and the modelling features in MACCS2, such as atmospheric diffusion coefficient, ground deposition, surface roughness, radioactive plume depletion, and exposure from ground deposition. Results and Discussion: An integrated accident consequence assessment code, ACCESS (Accident Consequence Assessment Code for Evaluating Site Suitability), was developed by taking into account the unique regulatory positions for reactor types under the framework of the current Korean technical standards. Field tracer experiments and hand calculations have been carried out for validation and verification of the models. Conclusion: The modelling approaches of ACCESS and its features are introduced, and its applicative results for a hypothetical accidental scenario are comprehensively discussed. In an applicative study, the predicted results by the light-water reactor assessment model were higher than those by other models in terms of total doses.

• 한국안전학회지
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• 제37권6호
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• pp.166-173
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• 2022

A variety of input parameters are taken into consideration while performing a Level 3 PSA. Some parameters related to plume segments, spatial grids, and particle size distribution have flexible input formats. Fine modeling performed by splitting a number of segments or grids may enhance the accuracy of analysis but is time-consuming. Analysis speed is highly important because a considerably large number of calculations is required to handle Level 2 PSA scenarios for a single-unit or multi-unit Level 3 PSA. This study developed a sensitivity analysis supporting interface called MACCSsense to compare the results of the trials of plume segmentation with the results of the base case to determine its impact (in terms of time and accuracy) and to support the development of a modeling approach, which saves calculation time and improves accuracy. MACCSense is an automation tool that uses a large amount of plume segmentation analysis results obtained from MUST Converter and Mr. Manager developed by KAERI to generate a sensitivity report that includes impact (time and accuracy) by comparing them with the base-case result. In this study, various plume segmentation approaches were investigated, and both the accuracy and speed of offsite consequence analysis were evaluated using MACCS as a consequence analysis tool. A simultaneous evaluation revealed that execution time can be reduced using multi-threading. In addition, this study can serve as a framework for the development of a modeling strategy for plume segmentation in order to perform accurate and fast offsite consequence analyses.

• 한국가스학회지
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• 제26권4호
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• pp.36-40
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• 2022

최근 산업계에서 가장 큰 화두는 산업안전보건관리에 대한 영역이다. 도시가스는 인화성 가스로 화재 및 폭발의 위험이 크기 때문에 중대 산업 및 시민 재해를 예방하기 위해 많은 노력이 요구된다. 본 연구에서는 도시가스 안전관리의 일환으로 Consequence Analysis를 통해 도시가스 누출에 의한 폭발사고 발생 시 피해 범위 및 정도를 정량적으로 예측하고자 하였다. 그 결과 압력, 기상상황 등 다양한 누출조건에 따라 분석결과 값에 차이를 보였다. 본 연구를 통해 도시가스 안전관리업무 수행 시 도시가스 누출에 의한 사고의 시나리오를 마련하여 보다 효과적인 사고예방과 비상조치계획을 마련하는데 활용할 예정이다.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1996년도 학술발표회
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• pp.53-56
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• 1996

In order to propose the method of the consequence analysis for fire accidents by the heavy gas release and to obtain optimum conditions of parameter selections, the consequence analysis for jet fire by the accident of xylene vapor release were performed. And the effect and the sensitivity analysis of parameters affecting the consequence were investigated. Simulation results showed that important parameters affecting results of the xylene vapor release accident were mainly hole diameter, interested distance, wind speed, and so on. For the jet fire, the accident result and the sensitivity of thermal radiation were increased with the decrease of interested distance and the increase of hole diameters, and the accidental result was increased as the increase wind speed, but the sensitivity of thermal radiation was decreased.

• 환경영향평가
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• 제13권1호
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• pp.1-8
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• 2004

A wide spectrum of risk assessments including qualitative and quantitative approaches and the analyses of its consequence were performed for an environmentally sensitive object such as incineration facility. To find out the major risk concerns, HAZOP(Hazard and Operability) were performed. Then, the frequency of hazardous gas release scenarios was calculated. Finally consequence analyses were performed for the gas release scenarios. On the basis of analyses through evaluation, a more innovative way for making a better control system or the enhancement of operation procedure was given. The results from these analyses would act as a substantial benefits for the incineration facility operator, and giving some measured information for the neighbors and the people involved.