• 한국수소및신에너지학회논문집
• /
• 제25권6호
• /
• pp.609-619
• /
• 2014

In the present study, the frequency of the undesired accident was estimated for a quantitative risk assessment of a large-scale hydrogen liquefaction plant. As a representative example, the hydrogen liquefaction plant located in Ingolstadt, Germany was chosen. From the analysis of the liquefaction process and operating conditions, it was found that a $LH_2$ storage tank was one of the most dangerous facilities. Based on the accident scenarios, frequencies of possible accidents were quantitatively evaluated by using both fault tree analysis and event tree analysis. The overall expected frequency of the loss containment of hydrogen from the $LH_2$ storage tank was $6.83{\times}10^{-1}$times/yr (once per 1.5 years). It showed that only 0.1% of the hydrogen release from the $LH_2$ storage tank occurred instantaneously. Also, the incident outcome frequencies were calculated by multiplying the expected frequencies with the conditional probabilities resulting from the event tree diagram for hydrogen release. The results showed that most of the incident outcomes were dominated by fire, which was 71.8% of the entire accident outcome. The rest of the accident (about 27.7%) might have no effect to the population.

• Nuclear Engineering and Technology
• /
• 제50권5호
• /
• pp.627-638
• /
• 2018

This article describes an integrated Level 1-Level 2 probabilistic risk assessment (PRA) methodology to evaluate the radiological risk during postulated accident scenarios initiated during the decommissioning phase of a typical Mark I containment boiling water reactor. The fuel damage scenarios include those initiated while the reactor is permanently shut down, defueled, and the spent fuel is located into the spent fuel storage pool. This article focuses on the integrated Level 1-Level 2 PRA aspects of the analysis, from the beginning of the accident to the radiological release into the environment. The integrated Level 1-Level 2 decommissioning PRA uses event trees and fault trees that assess the accident progression until and after fuel damage. Detailed deterministic severe accident analyses are performed to support the fault tree/event tree development and to provide source term information for the various pieces of the Level 1-Level 2 model. Source terms information is collected from accidents occurring in both the reactor pressure vessel and the spent fuel pool, including simultaneous accidents. The Level 1-Level 2 PRA model evaluates the temporal and physical changes in plant conditions including consideration of major uncertainties. The goal of this article is to provide a methodology framework to perform a decommissioning Probabilistic Risk Assessment (PRA), and an application to a real case study is provided to show the use of the methodology. Results will be derived from the integrated Level 1-Level 2 decommissioning PSA event tree in terms of fuel damage frequency, large release frequency, and large early release frequency, including uncertainties.

• Nuclear Engineering and Technology
• /
• 제44권5호
• /
• pp.437-452
• /
• 2012

The Tohoku earthquake (Mw9.0) occurred on March 11, 2011 and caused a large tsunami. The Fukushima Dai-ichi NPP (F1-NPP) were overwhelmed by the tsunami and core damage occurred. This paper describes the overview of F1-NPP accident and the usability of tsunami PRA at Tohoku earthquake. The paper makes reference to the following current issues: influence on seismic hazard of gigantic aftershocks and triggered earthquakes, concepts for evaluating core damage frequency considering common cause failure with correlation coefficient against seismic event at multi units and sites, and concepts of "seismic-tsunami PSA" considering a combination of seismic motion and tsunami effects.

• 대한방사선방어학회:학술대회논문집
• /
• 대한방사선방어학회 2010년도 춘계 학술발표회 및 심포지엄
• /
• pp.100-101
• /
• 2010

• International Journal of Safety
• /
• 제2권1호
• /
• pp.50-56
• /
• 2003

There are a lot of uncertainties in the severe accident phenomena and scenarios in nuclear power plants (NPPs) and one of the major issues for severe accident management is the reduction of these uncertainties. The severe accident management aid system using Probabilistic Safety Assessments (PSA) technology is developed for the management staff in order to reduce the uncertainties. The developed system includes the graphical display for plant and equipment status, previous research results by a knowledge-base technique, and the expected plant behavior using PSA. The plant model used in this paper is oriented to identify plant response and vulnerabilities via analyzing the quantified results, and to set up a framework for an accident management program based on these analysis results. Therefore the developed system may playa central role of information source for decision-making for severe accident management, and will be used as a training tool for severe accident management.

• 한국ITS학회 논문지
• /
• 제18권6호
• /
• pp.31-42
• /
• 2019

사고기록장치(Event data recorder, EDR)에 기록된 운행정보 중 차량의 사고 이전 속도정보는 사고차량 운전자의 처벌, 가해자·피해자 구분, 사고회피 가능성 등을 결정하는 매우 중요한 요소이다. 또한 EDR 자료를 분석하면 사고차량의 감속도를 분석할 수 있다. 본 연구에서는 교통사고 분석에서 사고차량 운전자의 전방주의의무 이행 여부, 사고회피 가능성 등을 판단하는 주요요소인 정지거리 산출에 적용 가능한 적정 감속도 값을 제시하기 위하여 선행연구의 제동실험 결과와 교통사고차량의 EDR에서 추출한 자료를 분석한 결과를 비교하였다. 선행연구의 ABS 장착차량 제동실험을 분석 결과, 차량의 평균 감속도는 0.79g~0.94g로 나타났다. 또한 비교적 최근에 이루어진 교통안전공단 자동차 안전도평가 제동실험에서는 감속도 값이 0.92g~0.94g로 매우 높게 나타났다. 그리고, 본 연구에서 수행된 EDR 자료 분석을 통해서는 0.55g~0.71g의 감속도 값이 산출되었으며, 선행연구의 제동실험에서 측정된 감속도 값보다 작은 값이 나타났다.

• 한국가스학회지
• /
• 제14권5호
• /
• pp.38-44
• /
• 2010

본 논문은 철도를 통해 운송되는 프로필렌의 사고위험을 정량적으로 분석하였다. 프로필렌의 수송 경로에 따라 사고 시 피해 위험이 높을 것으로 예상되는 지역인 익산역, 순천역, 전주역으로 대상지역을 선정하였다. 프로필렌의 운송 중 일어날 수 있는 사고유형을 고려한 후 ETA(Event Tree Analysis)를 이용하여 사고시나리오 및 발생빈도를 도출하였고, PHAST 6.53(Process Hazard Analysis Software Tool)을 이용하여 사고피해예측 평가 실시하여 주변에 미치는 피해정도를 산정함으로써 개인적.사회적 위험성정도를 제시하였다.

• 해양환경안전학회지
• /
• 제22권3호
• /
• pp.259-267
• /
• 2016

The study performs a risk analysis on container ship accidents using accident data collected over the six years from 2006 to 2011, presents the resulting risk level, and suggests three risk mitigation measures to reduce the overall risk, for the safer operation of container ships. More specifically, starting from the initial accident of collision, we developed 13 different accident scenarios using event tree analysis based on which the overall risk level was obtained and presented as a FN curve. Since diverse human factors are the main cause of most of the ship accidents, our study focuses on the effect of reducing human causes on the resulting risk level. For the research we considered the injuries for the calculation of fatality with the help of MAIS. The results show that collision was the main type of accident, accounting for 62 % of all accidents, and the measures employed were proven to be effective in the sense that the risk level was much lowered and the average number of fatalities was also reduced. With more data accumulated, more precise risk level will be calculated with which the practical risk mitigating measures will be also developed. For future study, economic loss and environmental damage as consequences need to be considered.

• 방사성폐기물학회지
• /
• 제20권3호
• /
• pp.339-347
• /
• 2022

Major accidents at nuclear power plants generate huge amounts of radioactive waste in a short period of time over a wide area outside the plant boundary. Therefore, extraordinary efforts are required for safe management of the waste. A well-established remediation plan including radioactive waste management that is prepared in advance will minimize the impact on the public and environment. In Korea, however, only limited plans exist to systematically manage this type of off-site radioactive waste generating event. In this study, we developed basic strategies for off-site radioactive waste management based on recommendations from the IAEA (International Atomic Energy Agency) and NCRP (National Council on Radiation Protection and Measurements), experiences from the Fukushima Daiichi accident in Japan, and a review of the national radioactive waste management system in Korea. These strategies included the assignment of roles and responsibilities, development of management methodologies, securement of storage capacities, preparation for the use of existing infrastructure, assurance of information transparency, and establishment of cooperative measures with international organizations.

• 한국의학물리학회지:의학물리
• /
• 제27권3호
• /
• pp.131-138
• /
• 2016

We analyzed the terminology and classification related to the risk management of radiation treatment overseas to establish the terminology and classification system for Korea. This study investigated the terminology and classification for radiotherapy risk management through overseas research materials from related organizations and associations, including the IAEA, WHO, British group, EC, and AAPM. Overseas risk management commonly uses the terms "near miss", "incident", and "adverse event", classified according to the degree of severity. However, several organizations have ambiguous terminologies. They use the term "near miss" for events such as a near event, close call, and good catch; the term "incident" for an event; and the term "adverse event" for the likes of an accident and an event. In addition, different organizations use different classifications: a "near miss" is generally classified as "incident" in most cases but not classified as such in BIR et al. Confusion might also be caused by the disunity of the terminology and classification, and by the ambiguity of definitions. Patient safety management of medical institutions in Korea uses the terms "near miss", "adverse event", and "sentinel event", which it classifies into eight levels according to the severity of risk to the patient. Therefore, the terminology and classification for radiotherapy risk management based on the patient safety management of medical institutions in Korea will help in improving the safety and quality of radiotherapy.