• 제목/요약/키워드: The event and accident

검색결과 495건 처리시간 0.025초

철도사고유형별 임시복구 표준운영체계(안) 개발 (Development of Standard Operation System of Emergency Restoration for Railway Accidents)

  • 박용걸;성덕룡;최승룡;서상교
    • 한국철도학회논문집
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    • 제12권5호
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    • pp.819-828
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    • 2009
  • 본 연구에서는 효율적이고 신속한 철도사고처리를 위해 임시복구 표준화(code) 및 표준운영체계(안)을 제시하고 있다. 우선, 철도사고유형을 국내 외 철도사고유형별 피해종류로 재분류하였으며, 이를 관련분야, 복구대상, 사고위치의 3자리 표준화된 코드로 제시하였다. 또한, 임시복구 표준운영체계(안) 수립방법을 정립하고 표준화된 임시복구 유형별 최악의 경우(worst case)와 임시복구절차 수립을 위한 중요항목(event)을 도출하여 임시복구유형별 임시복구 표준운영절차를 제시하였다. 이러한 표준화(code) 및 표준운영절차는 철도사고 DB관리, 신속한 사고처리 및 피해최소화를 위한 철도사고 비상대응관리체계 구축에 중요한 역할을 담당할 수 있을 것이다.

Simulation and Damage Analysis of an Accidental Jet Fire in a High-Pressure Compressed Pump Shelter

  • Jang, Chang Bong;Choi, Sang-Won
    • Safety and Health at Work
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    • 제8권1호
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    • pp.42-48
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    • 2017
  • Background: As one of the most frequently occurring accidents in a chemical plant, a fire accident may occur at any place where transfer or handling of combustible materials is routinely performed. Methods: In particular, a jet fire incident in a chemical plant operated under high pressure may bring severe damage. To review this event numerically, Computational Fluid Dynamics methodology was used to simulate a jet fire at a pipe of a compressor under high pressure. Results: For jet fire simulation, the Kemeleon FireEx Code was used, and results of this simulation showed that a structure and installations located within the shelter of a compressor received serious damage. Conclusion: The results confirmed that a jet fire may create a domino effect that could cause an accident aside from the secondary chemical accident.

원자력발전소의 화재사건 확률론적안전성평가 모델 구축에 관한 연구 (A Study on the Constructions of Fire Events Probabilistic Safety Assessment Model for Nuclear Power Plants)

  • 강대일;김길유
    • 한국안전학회지
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    • 제31권5호
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    • pp.187-194
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    • 2016
  • A single fire event within a fire area can cause multiple initiating events considered in internal events probabilistic safety assessment (PSA). For an example, a fire event in turbine building fire area can cause a loss of the main feed-water and loss of off-site power initiating events. This fire initiating event could result in special plant responses beyond the scope of the internal events PSA model. One approach to address a fire initiating event is to develop a specific fire event tree. However, the development of a specific fire event tree is difficult since the number of fire event trees may be several hundreds or more. Thus, internal fire events PSA model has been generally constructed by modifications of the pre-developed internal events PSA model. New accident sequence logics not covered in the internal events PSA model are separately developed to incorporate them into the fire PSA model. Recently, many fire PSA models have fire induced initiating event fault trees not shown in an internal event PSA model. Up to now, there has been no analytical comparative study on the constructions of fire events PSA model using internal events PSA model with and without fault trees of initiating events. In this study, the changing process of internal events PSA model to fire events PSA model is analytically presented and discussed.

Safety Analysis on the Tritium Release Accidents

  • Yang, Hee joong
    • 품질경영학회지
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    • 제19권2호
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    • pp.96-107
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    • 1991
  • At the design stage of a plant, the plausible causes and pathways of release of hazardous materials are not clearly known. Thus there exist large amount of uncertainties on the consequences resulting from the operation of a fusion plant. In order to better handle such uncertain circumstances, we utilize the Probabilistic Risk Assessment(PRA) for the safety analyses on fusion power plant. In this paper, we concentrate on the tritium release accident. We develop a simple model that describes the process and flow of tritium, by which we figure out the locations of tritium inventory and their vulnerability. We construct event tree models that lead to various levels of tritium release from abnormal initiating events. Branch parameters on the event tree are assessed from the fault tree analysis. Based on the event tree models we construct influence diagram models which are more useful for the parameter updating and analysis. We briefly discuss the parameter updating scheme, and finally develop the methodology to obtain the predictive distribution of consequences resulting from the operating a fusion power plant. We also discuss the way to utilize the results of testing on sub-systems to reduce the uncertain ties on over all system.

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ETA를 활용한 근로자의 불안전한 행동과 떨어짐 사고의 관계 (The Relationship between Unsafe Acts and Fall Accident of Workers Using ETA)

  • 정은빈;최재욱;이찬식
    • 한국건설관리학회논문집
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    • 제21권3호
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    • pp.28-38
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    • 2020
  • 최근 건설구조물의 대형화, 고층화로 인해 고소작업이 증가하며 떨어짐 사고(이하 사고)가 증가하고 있다. 근로자의 불안전한 행동이 산업재해의 주요 원인으로 밝혀지며, 불안전한 행동 예측 및 관리의 필요성이 제기되었다. 이 연구는 건설 현장에서 근로자의 불안전한 행동과 사고의 관계를 확률로 제시하여 불안전한 행동의 개선 효과를 산출하는 것을 목적으로 수행되었다. 재해사례를 분석하여 근로자의 불안전한 행동을 도출하고, 설문조사를 통하여 불안전한 행동으로 인한 사고의 발생 확률(이하 사고 확률)을 산출하였다. 사건수 분석 기법(Event Tree Analysis; ETA)을 활용하여 불안전한 행동의 조합에 따른 최종 사고 확률과 개선 효과를 확인하였다. 불안전한 행동별 사고 확률은 음주 후 작업 수행(95.41%)이 가장 높았고, 장비 및 기계 활용(65.70%)이 가장 낮았다. 불안전한 행동의 조합에 따른 사고 확률은 불안전한 행동을 모두 수행한 경우(13.23%)가 가장 높았고, 불안전한 행동을 수행하지 않은 경우(0.00%)가 가장 낮았다.

Analysis of severe accident progression and Cs behavior for SBO event during mid-loop operation of OPR1000 using MELCOR

  • Park, Yerim;Shin, Hoyoung;Kim, Seungwoo;Jin, Youngho;Kim, Dong Ha;Jae, Moosung
    • Nuclear Engineering and Technology
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    • 제53권9호
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    • pp.2859-2865
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    • 2021
  • One of the important issues raised from the Fukushima-Daiichi accident is the safety of multi-unit sites when simultaneous accidents occur at the site and recently a multi-unit PSA methodology is being developed worldwide. Since all operation modes of the plant should be considered in the multi-unit PSA, the accident analysis needs to be performed for shutdown operation modes, too. In this study, a station blackout during the mid-loop operation is selected as a reference scenario. The overall accident progression for the mid-loop operation is slower than that for the full-power operation because the residual heat per mass of coolant is about 6 times lower than that in the mid-loop scenario. Though the fractions of Cs released from the core to the RCS in both operation modes are almost the same, the amount of Cs delivered to the containment atmosphere is quite different due to the chemisorption in the RCS. While 45.5% of the initial inventory is chemisorbed on the RCS surfaces during the full-power operation, only 2.2% during the mid-loop operation. The containment remains intact during the mid-loop operation, though 83.9% of Cs is delivered to the containment.

Analysis of MBLOCA and LBLOCA success criteria in VVER-1000/V320 reactors: New proposals for PSA Level 1

  • Elena Redondo-Valero;Cesar Queral;Kevin Fernandez-Cosials;Victor Hugo Sanchez-Espinoza
    • Nuclear Engineering and Technology
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    • 제55권2호
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    • pp.623-639
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    • 2023
  • The specific configuration of the safety systems in VVER-1000/V320 reactors allows a comprehensive study of the Loss of Coolant Accident (LOCA). In the present paper, a verification of the success criteria of the event trees headers for the medium and large break LOCA sequences is conducted. A detailed TRACEV5P5 thermal-hydraulic model of the reactor has been developed, including all safety systems. When analyzing the results of all sequences, some conservatism is observed in certain specific configurations as the success criterion of some headers is not consistent with the classic PSA level 1. Therefore, new proposals for the LOCA event trees are performed based on a reconfiguration of LOCA break ranges and the use of the expanded event trees approach.

RESEARCH EFFORTS FOR THE RESOLUTION OF HYDROGEN RISK

  • HONG, SEONG-WAN;KIM, JONGTAE;KANG, HYUNG-SEOK;NA, YOUNG-SU;SONG, JINHO
    • Nuclear Engineering and Technology
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    • 제47권1호
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    • pp.33-46
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    • 2015
  • During the past 10 years, the Korea Atomic Energy Research Institute (KAERI) has performed a study to control hydrogen gas in the containment of the nuclear power plants. Before the Fukushima accident, analytical activities for gas distribution analysis in experiments and plants were primarily conducted using a multidimensional code: the GASFLOW. After the Fukushima accident, the COM3D code, which can simulate a multidimensional hydrogen explosion, was introduced in 2013 to complete the multidimensional hydrogen analysis system. The code validation efforts of the multidimensional codes of the GASFLOW and the COM3D have continued to increase confidence in the use of codes using several international experimental data. The OpenFOAM has been preliminarily evaluated for APR1400 containment, based on experience from coded validation and the analysis of hydrogen distribution and explosion using the multidimensional codes, the GASFLOW and the COM3D. Hydrogen safety in nuclear power has become a much more important issue after the Fukushima event in which hydrogen explosions occurred. The KAERI is preparing a large-scale test that can be used to validate the performance of domestic passive autocatalytic recombiners (PARs) and can provide data for the validation of the severe accident code being developed in Korea.

항공사고 피해자 가족지원 제도개선 연구 (Study on Improvement of Family Assistance System for Victim's Family of Air Traffic Accident)

  • 전종진;김휘양;유광의
    • 항공우주정책ㆍ법학회지
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    • 제33권2호
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    • pp.315-343
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    • 2018
  • 항공사고가 발생하게 되면 언론과 일반사회 구성원들은 사고로 인한 피해자에 주목하고 그들에 대한 조치나 보상에도 깊은 관심을 갖게 된다. 하지만, 지난 2002년 발생한 중국국제항공(CCA) 129편의 사고를 통해 우리는 항공사고로 인한 피해자 못지않게 그 가족들 또한 많은 고통을 받으며 심각한 사고 후유증을 겪는다는 현실적인 문제임를 확인할 수 있었다. 그럼에도 항공사고 피해자 가족에 대한 지원에 대한 우리나라의 관련 제도는 매우 빈약하다. 이에 반해 1996년 트랜스월드항공(TWA) 800편이 대서양 상공에서 폭발, 추락한 사고를 계기로 미국에서는 항공사고 피해자의 가족들을 지원하기 위한 법을 제정하였다. 그리고 이 법에 따라 항공사고 피해 당사자뿐만 아니라 그들의 가족들에 대한 체계적인 지원과 관리를 통해 피해자와 피해자 가족들의 추가적인 피해를 최소화 하고 조기에 사고 후유증으로부터 벗어날 수 있도록 지원하고 있다. 특히 2013년 아시아나항공(AAR) 214편이 미국 샌프란시스코 국제공항 착륙 중 추락한 사고에서 미국의 관련 당국이 이러한 법제에 따라 보여준 조치는 우리에게 항공사고에서의 피해자와 그 가족에 대한 지원에 대해 많은 시사점을 보여주고 있다. 이에 이 논문에서는 항공사고에서의 피해자와 피해자 가족 지원에 대한 제도개선의 필요성을 제언하고자 국내 외 관련 법제 체계와 과거 사고에서의 관련 사례를 분석하여 우리나라 제도의 부족한 점을 확인하였고, 관련 제도개선의 필요성을 도출하였다. 항공사고의 수습에서는 사고 피해자에 대한 금전적 피해보상도 중요하지만, 사고 피해자의 가족이 정신적 경제적인 충격으로부터 조기에 벗어나고 사고조사 결과에 대해 신뢰할 수 있도록 하는 것도 중요하다. 피해자 및 가족이 충격에서 벗어나고 사고조사를 신뢰하는 데에는 미국의 경우와 같이 그들에 대한 신속하고 체계적인 지원과 협조가 절실히 요구됨을 관련 정부부처와 항공사 및 유관기관에서는 인식하여야 한다. 그리고 항공기 사고 피해자 및 피해자 가족에 대한 지원을 위한 관련 법률의 보완, 실행 매뉴얼 제정, 계획 수립 및 사고 발생 시 신속한 이행을 위해 노력하여야 할 것이다. 이를 위해 항공사고 피해자 및 가족 지원에 대한 국가와 국가기관의 역할과 책임의 법적 제도화를 위한 규정을 마련할 필요가 있다. 그리고 현행 법률에 명시된 항공사가 제출하여야 하는 피해자 및 가족 지원계획은 그 항목을 구체화할 필요가 있다. 추가하여 신설 및 보완된 내용은 명확한 법 적용을 위해 기존 법률에 단일 조항으로 통합하거나 별도의 특별법으로 제정하는 방안도 제안해 본다.

Finding Hazard Factors by New Risks on Maritime Safety in Korea

  • Park, Deuk-Jin;Park, Seong-Bug;Yang, Hyeong-Sun;Yim, Jeong-Bin
    • 해양환경안전학회지
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    • 제22권3호
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    • pp.278-285
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    • 2016
  • The key features of maritime accidents are the change of their attributes by new risks from time to time. To prevent maritime accidents in Korea, the impacts by new risks on domestic safety environments should be identified or predicted. The purpose of this paper is to find the hazard factors by new risks on maritime safety in Korea. The meaning of new risks is the elements of accident hazard which is compiled from new or rare or unprecedented events in the worldwide maritime transportations. The problems of new risks are the lacks of optimum countermeasures to mitigate accident risks. Using the questionnaires with 152 event scenarios classified by 20 accident causes, the hazard identification and risk analysis of new risks was performed based on the Formal Safety Assessment (FSA) by IMO. A total of 22 Influence Diagrams, which is to depict the transit flows between accident causes to consequences, is used in the construction of 152 event scenarios. A total of 20 accidents causes is the same contents as the causation factors represented in Statistical Year Book for Maritime Accidents of Korean Maritime Safety Tribunals. After defining the evaluation equations to the response results of questionnaires by 46 experts, the work for risk analysis is carried out. As results from the analysis of 152 scenarios, it is known that the root cause to affect on maritime safety in Korea is the pressure of business competition and it led to the lacks of well experienced crews, the overload of vessel operations and crew's fatigue. In addition, as results from the analysis of 20 accident causes, the three accident causes are to be candidate as main issues in Korea such as the inadequate preparedness of departure, the neglecting of watch keeping in bridge and the inadequate management of ship operations. All of the results are thought to be as basic hazard factors to safety impediments. It is thus found that the optimum Risk Control Options to remove the hazard factors and to mitigate consequences required are the following two factors: business competition and crewing problems.