생태학적 인터페이스 디자인 프레임워크에 기반한 원전 중대사고 지원 정보디스플레이 개념설계

조필재,함동한,이현철 대한안전경영과학회 2022 대한안전경영과학회지 Vol.24 No.1

This study aims to propose a conceptual design of information displays for supporting responsive actions under severe accidents in Nuclear Power Plants (NPPs). Severe accidents in NPPs can be defined as accident conditions that are more severe than a design basis accident and involving significant core degradation. Since the Fukushima accident in 2011, the management of severe accidents is increasing important in nuclear industry. Dealing with severe accidents involves several cognitively complex activities, such as situation assessment; accordingly, it is significant to provide human operators with appropriate knowledge support in their cognitive activities. Currently, severe accident management guidelines (SAMG) have been developed for this purpose. However, it is also inevitable to develop information displays for supporting the management of severe accidents, with which human operators can monitor, control, and diagnose the states of NPPs under severe accident situations. It has been reported that Ecological Interface Design (EID) framework can be a viable approach for developing information displays used in complex socio-technical systems such as NPPs. Considering the design principles underlying the EID, we can say that EID-based information displays can be useful for dealing with severe accidents effectively. This study developed a conceptual design of information displays to be used in severe accidents, following the stipulated design process and principles of the EID framework. We particularly attempted to develop a conceptual design to make visible the principle knowledge to be used for coping with dynamically changing situations of NPPs under severe accidents.

Severe Accident Issues Raised by the Fukushima Accident and Improvements Suggested

송진호,김태운 한국원자력학회 2014 Nuclear Engineering and Technology Vol.46 No.2

This paper revisits the Fukushima accident to draw lessons in the aspect of nuclear safety considering the fact that theFukushima accident resulted in core damage for three nuclear power plants simultaneously and that there is a high possibilityof a failure of the integrity of reactor vessel and primary containment vessel. A brief review on the accident progression at Fukushima nuclear power plants is discussed to highlight the nature andcharacteristic of the event. As the severe accident management measures at the Fukushima Daiich nuclear power plants seemto be not fully effective, limitations of current severe accident management strategy are discussed to identify the areas for thepotential improvements including core cooling strategy, containment venting, hydrogen control, depressurization of primarysystem, and proper indication of event progression. The gap between the Fukushima accident event progression and currentunderstanding of severe accident phenomenology including the core damage, reactor vessel failure, containment failure, andhydrogen explosion are discussed. Adequacy of current safety goals are also discussed in view of the socio-economic impact of the Fukushima accident. As aconclusion, it is suggested that an investigation on a coherent integrated safety principle for the severe accident anddevelopment of innovative mitigation features is necessary for robust and resilient nuclear power system

SEVERE ACCIDENT ISSUES RAISED BY THE FUKUSHIMA ACCIDENT AND IMPROVEMENTS SUGGESTED

Song, Jin Ho,Kim, Tae Woon Korean Nuclear Society 2014 Nuclear Engineering and Technology Vol.46 No.2

This paper revisits the Fukushima accident to draw lessons in the aspect of nuclear safety considering the fact that the Fukushima accident resulted in core damage for three nuclear power plants simultaneously and that there is a high possibility of a failure of the integrity of reactor vessel and primary containment vessel. A brief review on the accident progression at Fukushima nuclear power plants is discussed to highlight the nature and characteristic of the event. As the severe accident management measures at the Fukushima Daiich nuclear power plants seem to be not fully effective, limitations of current severe accident management strategy are discussed to identify the areas for the potential improvements including core cooling strategy, containment venting, hydrogen control, depressurization of primary system, and proper indication of event progression. The gap between the Fukushima accident event progression and current understanding of severe accident phenomenology including the core damage, reactor vessel failure, containment failure, and hydrogen explosion are discussed. Adequacy of current safety goals are also discussed in view of the socio-economic impact of the Fukushima accident. As a conclusion, it is suggested that an investigation on a coherent integrated safety principle for the severe accident and development of innovative mitigation features is necessary for robust and resilient nuclear power system.

PREDICTION OF SEVERE ACCIDENT OCCURRENCE TIME USING SUPPORT VECTOR MACHINES

김승근,노영규,성풍현 한국원자력학회 2015 Nuclear Engineering and Technology Vol.47 No.1

If a transient occurs in a nuclear power plant (NPP), operators will try to protect the NPP byestimating the kind of abnormality and mitigating it based on recommended procedures. Similarly, operators take actions based on severe accident management guidelines whenthere is the possibility of a severe accident occurrence in an NPP. In any such situation,information about the occurrence time of severe accident-related events can be veryimportant to operators to set up severe accident management strategies. Therefore, supportsystems that can quickly provide this kind of information will be very useful whenoperators try to manage severe accidents. In this research, the occurrence times of severalevents that could happen during a severe accident were predicted using support vectormachines with short time variations of plant status variables inputs. For the preliminarystep, the break location and size of a loss of coolant accident (LOCA) were identified. Training and testing data sets were obtained using the MAAP5 code. The results show thatthe proposed algorithm can correctly classify the break location of the LOCA and can estimatethe break size of the LOCA very accurately. In addition, the occurrence times ofsevere accident major events were predicted under various severe accident paths, withreasonable error. With these results, it is expected that it will be possible to apply theproposed algorithm to real NPPs because the algorithm uses only the early phase data afterthe reactor SCRAM, which can be obtained accurately for accident simulations

Evaluation of an accident management strategy using an emergency water injection in a reference PWR SFP

Ahn, Kwang-Il,Jung, YongHun,Shin, Jae-Uk,Kim, Won-Tae Elsevier 2018 Annals of nuclear energy Vol.113 No.-

<P><B>Abstract</B></P> <P>The Fukushima accident on March 11, 2011 has shown the relevance of examinations of severe accident inside a spent fuel pool (SFP) during beyond-design-basis external events, and the necessity for provisions to cope effectively with such events through a relevant severe accident management (SAM) strategy. Although the low decay heat of fuel assemblies and the considerable water inventory in an SFP can slow the progress of an accident compared to an accident in the reactor core, the numerous number of fuel assemblies stored inside it and the fact that the SFP building is not leak-tight present the potential for the formation of a direct path for fission products to rise from the SFP into the environment (i.e., a much greater severe accident risk). The purpose of this paper is to assess the effectiveness and success conditions of an emergency makeup water injection strategy, which is being as a representative SFP SAM measure after the Fukushima accident. Two typical accident scenarios (loss-of-cooling and loss-of-pool-inventory accidents) and two different reactor operating modes (normal and refueling modes) were considered in the analysis. For the foregoing SAM strategies, the analysis results and relevant insights are summarized in relation to two major aspects: (a) the key events of the progression of an accident (such as the exposure, heat-up and degradation of the fuel assemblies; the generation of combustible gases such as Hydrogen; and the over-pressurization of the SFP building) and (b) the release of radiological fission products (such as Cesium and Iodine) into the environment. A simulation tool for severe accidents, MELCOR1.8.6, was used in the present analysis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A SAM strategy for SFP using a water injection is assessed for a PWR. </LI> <LI> Loss-of-cooling/inventory accidents and different reactor operating modes are considered in the analysis. </LI> <LI> Analysis results are given for severe accident progressions and the release of fission products. </LI> <LI> Key insights obtained through the analysis are summarized from a SFP SAM position. </LI> </UL> </P>

원자력시설에 대한 테러 및 중대사고 리스크의 사전관리제도에 관한 연구 ― 미국의 환경영향평가제도를 중심으로 ―

윤혜선 한국환경법학회 2019 環境法 硏究 Vol.41 No.1

Since the Fukushima accident in March 2011, the regulatory interests in severe accidents in nuclear facilities have been greatly increased. Severe accidents are those in which substantial damage is done to the reactor core beyond the design basis. These can occur from causes such as natural disasters including earthquakes, tornadoes, floods, but also artificial events, namely, aircraft crashes, explosions, cyber attacks and terrorism. Korea, which has recently adopted various legal tools to manage severe accidents, is in need to search for better tools to manage the risks of severe accident and terrorism in nuclear facilities. However, there is an interesting phenomenon at home and abroad in this regard: this search goes beyond the discussions of improving and strengthening safety and security regulations within the framework of the nuclear law and has formed a discourse of “environmental risk” under the environmental law. Given this background, this article examined the suitability of the environmental impact assessment(EIA) as an ex ante management tool for the risks of terrorism and severe accident in nuclear facilities under the U.S. law. Specifically, the following four questions were addressed by reviewing several U.S. case laws on the U.S. Atomic Energy Act of 1954(AEA), the National Environmental Policy Act of 1969(NEPA) and the Environmental Impact Statements(EIS). First, if the safety and physical protection regulations are adequately implemented on nuclear facilities under the AEA, would the NEPA’s review be unnecessary? Secondly, is the EIS meaningful as an ex ante management tool for the risks of terrorism or severe accidents? Third, would the consideration of severe accidents in the EIS make that of terrorism, which is only one of many causes of severe accident, unnecessary? And finally, if the EIS can be justified as a meaningful tool, what more are necessary to make it more useful? Accordingly, this article is organized as follows. In Part II, it briefly described overviews of the AEA and the NEPA, and discussed how US courts have interpreted the NEPA's causality requirement to determine effects that should or should not be considered in the EIS. In Parts III and IV, it examined how courts have dealt with the issues of considering the severe accident and terrorism under the NEPA, respectively. Finally in Part V, it reviewed the above-mentioned four issues and proposed agenda for the subsequent study. 2011년 3월 발생한 후쿠시마 원자력발전소 사고 이후 원자력시설의 중대사고에 대한 관심이 크게 확대되었다. 중대사고란 원자력발전소의 설계기준을 초과하여 원자로의 중심부분인 노심에 손상이 발생하는 사고를 말한다. 중대사고는 지진・태풍・홍수・해일・회오리바람 등 자연재해뿐만 아니라 항공기 충돌, 폭발, 사이버공격, 테러와 같은 인위적 사건에 의해서도 발생할 수 있다. 최근에서야 중대사고 관리를 위한 법제 정비를 한 우리나라는 원자력시설의 중대사고 및 테러 리스크의 사전관리를 위한 다양한 법적, 제도적 연구가 필요한 실정이다. 그런데 원자력시설에 대한 테러나 중대사고의 문제를 다루는 데 있어서 국내외에서 흥미로운 현상이 나타나고 있다. 이 문제들이 원자력법의 체계 내에서 안전 및 안보 규제를 개선하고 강화하는 논의의 차원을 넘어 ‘환경 리스크’로 인식되고 그에 적절한 사전관리가 필요하다는 담론을 형성하고 있기 때문이다. 이러한 배경 하에 본고에서는 원자력시설에 대한 테러 및 중대사고 리스크의 사전관리수단으로서 환경영향평가제도의 의의를 상대적으로 많은 논의가 축적되어 있는 미국법제를 중심으로 고찰해 보았다. 구체적으로 다음의 네 가지 질문을 미국의 「원자력법」과 「국가환경정책법」 및 환경영향평가제도에 관한 여러 가지 미국 법원의 판례를 검토하여 다루었다. 첫째, 원자력안전법제에 따라 원자력시설에 대한 실체적 안전 및 물리적 방호 규제가 이루어졌다면 절차에 불과한 환경법제에 의한 환경영향평가는 불필요한 것이 아닌지, 둘째, 환경영향평가제도가 테러행위나 중대사고 리스크의 사전관리수단으로 과연 유의미한 것인지, 셋째, 중대사고에 대한 환경영향평가가 이루어졌다면 중대사고의 발생원인 중 하나에 불과한 테러행위에 대한 환경영향평가는 불필요한 것이 아닌지, 넷째, 중대사고와 테러행위에 대한 사전관리수단으로 환경영향평가제도를 활용하는 것이 정당화된다면, 이 제도를 잘 활용하기 위해서는 어떠한 노력이 필요한지 등이다. 본고의 구성은 다음과 같다. 먼저 미국 「원자력법」과 「국가환경정책법」의 체계를 본고의 논의에 필요한 내용을 중심으로 간략히 개관하고, 「국가환경정책법」에 따라 환경영향평가를 할 때 고려해야 하는 영향을 결정하는 기준에 관한 법령과 판례의 기준을 살핀 다음, 원자력시설 관련 허가 과정에서 중대사고와 테러 리스크를 환경영향평가에서 고려해야 하는 문제를 다룬 판례들을 검토하였다. 마지막으로 이러한 내용에 비추어 위의 네 가지 문제에 대한 검토와 후속 연구에 대한 문제제기를 하는 것으로 글을 마무리하였다.

교통사고 심각도 예측 모형의 활용방안에 관한 연구 (서해안 고속도로를 중심으로)

원민수,이겨라,오철,강경우 대한교통학회 2009 대한교통학회지 Vol.27 No.4

It is important to study on the traffic accident severity reduction because traffic accident is an issue that is directly related to human life. Therefore, this research developed countermeasure to reduce traffic accident severity considering various factors that affect the accident severity. This research developed the Accident Severity Prediction Model using the collected accident data from Seohaean Expressway in 2004~2006. Through this model, we can find the influence factors and methodology to reduce accident severity. The results show that speed limit violation, vehicle defects, vehicle to vehicle accident, vehicle to person accident, traffic volume, curve radius CV(Coefficient of variation) and vertical slope CV were selected to compose the accident severity model. These are certain causes of the severe accident. The accidents by these certain causes present specific sections of Seohaean Expressway. The results indicate that we can prevent severe accidents by providing selected traffic information and facilities to drivers at specific sections of the Expressway. 교통사고는 인간의 생명과 직결되는 문제이므로, 교통사고 예방 및 심각도 감소를 위한 연구는 매우 중요하다고 할 수 있다. 따라서 본 연구에서는 교통사고심각도에 영향을 줄 수 있는 다양한 영향요소들을 고려하여 교통사고로 인한 피해를 최소화할 수 있는 대응책을 수립하고자 하였다. 본 연구에서는 2004~2006년 동안 서해안 고속도로에서 발생한 174개의 구간별 사고자료를 이용하여 사고 심각도 예측모형을 만들었다. 이렇게 분석된 모형을 이용하여 사고심각도에 영향을 미치는 주요요인을 찾고 이를 이용하여 교통사고로 인한 피해를 줄일 수 있는 다양한 방법들을 고려해 보았다. 분석결과 과속으로 인한 사고, 차량결함, 차대차 사고, 차대사람 사고, 교통량, 곡선반경 및 종단경사 변동계수에 의해 사고심각도가 정의되는 것을 알 수 있다. 이와 같은 사고심각도와 밀접한 관련이 있는 독립변수들을 대상으로 구간에 따른 각 영향의 정도를 그래프를 나타내 보았으며, 그 결과 심각한 사고를 유발하는 특정원인이 몇 가지 존재하며 이러한 특정원인 및 사고유형은 서해안 고속도로의 특정구간에서 주로 발생한다는 것을 알 수 있다. 이러한 결과들은 서해안 고속도로의 특정 구간에 속도제한 단속 카메라, 차내/외 경고정보제공등과 같은 선택적 교통정보 및 교통시설을 제공함으로써 사고를 예방하는 방법에 활용될 수 있을 것이다.

고령운전자 인적요인별 교통사고 피해손상연구

심은석 ( Eun Seok Sim ) 한국경찰이론과실무학회 2009 경찰연구논집 Vol.5 No.-

고령화 시대에 고령자의 안전한 이동을 보장하는 교통안전정책이 필요하다. 교통사고는 인적요인 단독으로 발생하기 보다는 도로 환경, 차량 요인들이 복합적으로 발생하는데, 노화에 따른 인적요인은 피해손상에 유의미한 차이가 있는데 이는 신체적, 인지, 반응, 정보처리 능력이 저하되었기 때문으로 판단하였다. 1) 본 연구는 특정 기간과 일정 범위의 장소에서 고령운전자가 제 1당사자로 판정된 교통사고 자료를 수집, 통계 분석 하였다. 따라서 이 연구는 2006년 1년간 대전, 충남에서 교통사고를 발생시켜 가해자(제1당사자)로 판정된 사고 559건을 추출하여 교통사고 발생요인 104가지 항목 중 고령운전자의 인적요인(성별, 연령별, 운전경력별, 면허종별, 법규위반별, 가입보험별, 음주운전별)이 교통사고 피해손상(피해 손상의 심각도, 피해비용) 의 차이에 대한 자료를 통계 분석하고 예방대책을 제시 하였다. 대전 충남 고령운전자가 발생시킨 교통사고의 실태는 고령운전자의 치사율이(10.38)로 전국고령운전자 치사율(6.62)보다 높고 전국(2.96)과 대전, 충남 치사율(5.03) 보다 매우 높으며 심각사고율(67.4%)이 높고 피해비용도 큰 것을 발견하였다.(총 피해비용; 364억7200만원, 1건당 평균:65,245 천원발생) 인적요인별 통계처리 결과 주요발견사항은 ① 여성운전자 심각사고율과 피해비용이 높고, ② 연령대가 높을수록 심각사고율, 피해비용 증가, ③ 면허종별로는 이륜면허 심각사고율과 피해비용이 높고 무면허사고율(11.4%)이 높고 이륜면허 사고율이 전국(3.6%)보다 (24.2%)로 매우 높음. ④ 운전경력별로는 5년 미만 초보 운전자 심각사고율 (81.6%)이 높음 ⑤ 위반법 규별로는 교차로 내 위반이 가장 높고 안불 사고 피해비용이 가장 큼 ⑥ 보험가입별로는 책임보험과 무보험 가입자 사고가 47.4%로 높고 무보험자심각사고율(81.8%)이 높고 평균피해비용도 (무보험자 79,109천원, 책임보험 75,415천원) 으로 피해자 보상이 제대로 안 될 것으로 판단함 ⑦ 음주 운전여부별로는 음주사고가 8.4%로(전국전체 사고율 14%, 충남16.62%) 낮으며, 심각사고율이 정상운전자보다 낮고 피해비용도 적음(63,586천원)을 발견하였다. 이에 대한 교통사고 예방대책은 고령운전자에 대한 교육과 면허규제, 교차로 개선 등 교통 환경 개선과 고령운전자 표지 활용, 교통 정온화 기법적용, 고령운전자 전용 차량도입방안을 제시 하였다. In this context, the author have been carrying out this study to get basic data for the traffic safety policy ensuring senior citizen`s right of safe mobility. 559 cases of car accidents in which senior citizens had been proved to be culprits have been selected in Daejeon and Chungnam province during the year of 2006 and the effect of traffic accident damage(severe damage degree, expenses for damage) was analyzed by the elderly driver`s human factors(sex, age, driving career, kinds of driving license, violation of law, insurance, driving under the influence of alcohol) as the independent variable among the 104 items variables of traffic accident factors. Traffic accidents in both Daejeon and Chungnam province were tested with fourteen hypothesis, which resulted in the finding of significant human factors such as ages, kinds of license, violation of law. Main findings are followings; death rate of senior citizen driver(10.38) is higher than that of whole nation(6.62) and severe accident rate(67.4%) and damage expense is much higher.(whole damage expense : 36,472,000,000 won, average for each case : 65,245,000 won) Also there are other meaningful findings regarding to human factors. 1. Women drivers cause severer accident rate and higher accident expense. 2. The older drivers cause more severe accidents and damage expenses. 3. Concerning driving license, two-wheeled vehicle drivers cause severe accident rate and higher damage expense and unlicensed driving accident rate is higher, two-wheeled license accident rate(24.2%) is much higher than that of whole nation`s(3.6%) 4. Concerning the driving career, severe accident rate for under 5 year career drivers is higher. 5. Concerning the violation of traffic law, an accident rate at the crossroads is higher and expense for violation of safe driving is the highest. 6. Concerning the insurance, accident frequency for drivers buy the liability insurance and without any insurance is high(47.4%), and severe accident rate for drivers without any insurance is also high(81.8%), and then it is estimated that compensation for the accident damage would not be paied because of average damage expense(without license : 79,109,000 won, liability insurance : 75,415,000 won) is much high. 7. Concerning drinking and driving, accidents by drinking and driving is lower(8.4%) than that of whole nation`s and found that severe accident rate is also lower, and damage expense is low(63,586,000won) either.

Severe accident analysis of plant-specific spent fuel pool to support a SFP risk and accident management

Ahn, K.I.,Shin, J.U.,Kim, W.T. Pergamon Press ; Elsevier Science Ltd 2016 Annals of nuclear energy Vol.89 No.-

The Fukushima accident that happened on March 11, 2011 has raised the possibility of severe accidents in an SFP under beyond design basis external events (BDBEEs) that might lead to a loss of all safety functions and need a way to cope effectively with such an event through a SFP risk and accident management. From a SFP safety point of view, the low decay heat of the fuel assemblies and large water inventory in an SFP may make the accident processes slow compared to an accident in the reactor core, but a huge number of fuel assemblies stored inside it and no containment in a SFP building (especially for PWR types) might be exposed to much greater risk. A quantitative analysis for SFP accidents can give more insights into which aspects play dominant roles in an accident progression. To date, however, few studies have been made for severe plant-level SFP accidents. This paper provides the plant-specific MELCOR analysis results for potential severe accidents that can be expected in a typical PWR. The SFP of the reference plant is located adjacent to the primary containment (outside primary containment), and its bottom is placed above the plant grade. Three representative accident scenarios (loss of cooling accident, loss of coolant inventory, and complete loss of coolant accident) and two different reactor operating modes (normal operation and refuelling mode) have been considered for the analysis. From the risk and accident management point of view, phenomenological analysis was mainly focused on (a) the level of the coolant, (b) the cladding temperature, (c) the mass of hydrogen generated during accident progressions, and (d) MCCI (Molten Corium Concrete Interaction).

APPLICATION OF SEVERE ACCIDENT MANAGEMENT GUIDANCE IN THE MANAGEMENT OF AN SGTR ACCIDENT AT THE WOLSONG PLANTS

Jin, Young-Ho,Park, Soo-Yong,Song, Yong-Mann Korean Nuclear Society 2009 Nuclear Engineering and Technology Vol.41 No.1

A steam generator tube rupture (SGTR) accident, which is a partial reactor building bypass scenario, has a low probability and high consequences. SAMG has been used to manage the progression of severe accidents and the release of fission products induced by an SGTR at the Wolsong plants. Four of the six SAGs in the SAMG are used to manage the progression of a severe accident induced by an SGTR at the Wolsong plants. The results of the ISAAC code calculation have shown that the proper use the SAMG can stop a severe accident from progressing and keep the reactor building intact during a severe accident. These results confirm that the SAMG is an effective means of managing the progression of severe accidents initiated by an SGTR at the Wolsong plants.