• Nuclear Engineering and Technology
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• v.38 no.8
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• pp.697-732
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• 2006

In this paper, a historical review of the developments in the safety of LWR power plants is presented. The paper reviews the developments prior to the TMI-2 accident, i.e. the concept of the defense in depth, the design basis, the large LOCA technical controversies and the LWR safety research programs. The TMI-2 accident, which became a turning point in the history of the development of nuclear power is described briefly. The Chernobyl accident, which terrified the world and almost completely curtailed the development of nuclear power is also described briefly. The great international effort of research in the LWR design-base and severe accidents, which was, respectively, conducted prior to and following the TMI-2 and Chernobyl accidents is described next. We conclude that with the knowledge gained and the improvements in plant organisation/management and in the training of the staff at the presently-installed nuclear power stations, the LWR plants have achieved very high standards of safety and performance. The Generation 3+LWR power plants, next to be installed, may claim to have reached the goal of assuring the safety of the public to a very large extent. This review is based on the historical developments in LWR safety that occurred primarily in USA, however, they are valid for the rest of the Western World. This review can not do justice to the many fine contributions that have been made over the last fifty years to the cause of LWR safety. We apologize if we have not mentioned them. We also apologize for not providing references to many of the fine investigations, which have contributed towards LWR safety earning the conclusions that we describe just above.

• Korean Journal of Remote Sensing
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• v.28 no.1
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• pp.129-143
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• 2012

This paper demonstrates the effectiveness of advanced spatial modeling techniques for environmental monitoring and impact assessment through a case study of Chernobyl nuclear accident occurred in 1986. Land-cover types changed after the accident are analysed by a post classification comparison method using bi-temporal Landsat TM data acquired in 1986 and 1992 near the accident site. Spatial modeling including various kriging algorithms are also applied to analyze the relationships between Cesium concentrations in soil and thyroid cancer incidence rates in Belarus, which was greatly damaged by the accident. The change detection results clearly showed the decrease of croplands and the increase of abandoned lands, and concrete structures were newly built around the nuclear plant to prevent the spread of radioactive contamination. In Belarus, high Cesium concentrations were observed in southern areas with high thyroid cancer risk estimated by Poisson kriging. Geographically weighted regression, which could account for geographic variations of independent variables including Cesium concentrations and distances from the Chernobyl nuclear power plant, was applied to extract the relationships between the independent variables and the thyroid cancer risk. The estimated risk values showed a correlation coefficient value of 0.98 with respect to the thyroid cancer risk values, which implied that the thyroid cancer risk in Belarus was affected by the accident. In conclusion, it is expected that advanced spatial modeling techniques applied in this study would be useful for environmental impact assessment and public health research.

• Fire Protection Technology
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• s.10
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• pp.27-33
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• 1991

The chernobyl disaster, the most serious and recent incident at an atomic plant, focussed worldwide attention on the danger of nuclear power. In this article, We discuss the fire hazards in nucleer power stations and some of the precautions necessary. Also this deals with each of the reactor components in turn, and the examples of incidents in the nuclear power stations are briefty discribed.

• Environmental and Resource Economics Review
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• v.26 no.2
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• pp.139-172
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• 2017

Nuclear safety measures such as safety technology, culture, and regulation affects nuclear performances. This paper analyzes the change of nuclear performance by considering nuclear safety measures. Nuclear performance and technical data ranging 1970 to 2015 are collected from the Power Reactor Information System (PRIS) of IAEA. The result of panel regression analysis shows that overall engineering level, maintenance engineering and productivity decrease the forced loss rate (FLR). FLR structurally increase after Chernobyl accident in 1986 whereas after TMI and Fukushima accidents FLR didn't show any significant changes. The structural increase of FLR after Chernobyl are likely to result from the efforts of international communities for nuclear safety culture which makes nuclear operating company pay more opportunity cost to achieve nuclear safety.

• Journal of Radiation Industry
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• v.9 no.4
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• pp.209-216
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• 2015

It has been about 5 years since the Fukushima nuclear power plant accident, which contaminated large area with radioactive materials. It is necessary to assess radiation dose to establish evacuation areas and to set decontamination goal for the large contaminated area. In this study, we assessed temporal trend of radiation dose to the public living in the large area contaminated with radioactive materials after the Fukushima nuclear power plant accident. The dose assessment was performed based on Chernobyl model and RESRAD model for two evacuation lift areas, Kawauchi and Naraha. It was reported that deposition densities in the areas were $4.3{\sim}96kBq\;m^{-2}$ for $^{134}Cs$, $1.4{\sim}300kBq\;m^{-2}$ for $^{137}Cs$, respectively. Radiation dose to the residents depended on radioactive cesium concentrations in the soil, ranging $0.11{\sim}2.4mSv\;y^{-1}$ at Kawauchi area and $0.69{\sim}1.1mSv\;y^{-1}$ at Naraha area in July 2014. The difference was less than 5% in radiation doses estimated by two different models. Radiation dose decreased with calendar time and the decreasing slope varied depending on dose assessment models. Based on the Chernobyl dosimetry model, radiation doses decreased with calendar time to about 65% level of the radiation dose in 2014 after 1 year, 11% level after 10 years, and 5.6% level after 30 years. RESRAD dosimetry model more slowly decreased radiation dose with time to about 85% level after 1 year, 40% level after 10 years, and 15% level after 30 years. The decrease of radiation dose can be mainly attributed into radioactive decays and environmental transport of the radioactive cesium. Only environmental transports of radioactive cesium without consideration of radioactive decays decreased radiation dose additionally 43% after 1 year, 72% after 3 years, 80% after 10 years, and 83% after 30 years. Radiation doses estimated with cesium concentration in the soil based on Chernobyl dosimetry model were compared with directly measured radiation doses. The estimated doses well agreed with the measurement data. This study results can be applied to radiation dose assessments at the contaminated area for radiation safety assurance or emergency preparedness.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.1
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• pp.5-15
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• 1997

This paper mentions a fault tree analysis using not probability but natural language and fuzzy theory, Reliability estimate of each basic event and dependence level estimate among subsystems are expressed by linguistic terms. Analysis results are also expressed by natural language. The meaning of linguistic terms is expressed by a fuzzy set. In the presented analysis approach parametrized operations of fuzzy sets are considered so that analyst's subjectivity can be introduced into the analysis. This paper gives the Chernobyl accident as an example of the fuzzy fault tree analysis using linguistic terms.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.06a
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• pp.276-282
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• 2000

지금까지 가장 널리 사용되는 원전 안전성의 평가는 설비고장이나 인간오류와 관련된 조직(Institution/organization)의 질이 설비의 신뢰도와 인적오류에 영향을 주며 원전의 안전성에 전반적인 영향을 끼친다는 것을 고려하지 않고 있다. TMI 사고는 경미한 설비고장은 있었으나 중요한 사고원인은 운전원의 오류였다. 운전원 훈련양의 부족, 절차서의 불명확성, 주제어실의 설계상의 결함 등이 함께 어울어진 안전문화와 관련한 조직실패(Organizational Failure)였다. Chernobyl사고도 전반적인 관리조절(Management Control)의 부족과 운전원의 부적절한 실험 절차서의 검토, 안전 절차서의 위배 등이 함께 연루되어 발생하였다. (중략)

• Proceedings of the Korean Nuclear Society Conference
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• 2004.05a
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• pp.398-398
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• 2004

• Environmental Analysis Health and Toxicology
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• v.31
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• pp.1.1-1.13
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• 2016

Objectives To investigate the accuracy and scientific validity of the current very low risk factor for hereditary diseases in humans following exposures to ionizing radiation adopted by the United Nations Scientific Committee on the Effects of Atomic Radiation and the International Commission on Radiological Protection. The value is based on experiments on mice due to reportedly absent effects in the Japanese atomic bomb (A-bomb) survivors. Methods To review the published evidence for heritable effects after ionising radiation exposures particularly, but not restricted to, populations exposed to contamination from the Chernobyl accident and from atmospheric nuclear test fallout. To make a compilation of findings about early deaths, congenital malformations, Down's syndrome, cancer and other genetic effects observed in humans after the exposure of the parents. To also examine more closely the evidence from the Japanese A-bomb epidemiology and discuss its scientific validity. Results Nearly all types of hereditary defects were found at doses as low as one to 10 mSv. We discuss the clash between the current risk model and these observations on the basis of biological mechanism and assumptions about linear relationships between dose and effect in neonatal and foetal epidemiology. The evidence supports a dose response relationship which is non-linear and is either biphasic or supralinear (hogs-back) and largely either saturates or falls above 10 mSv. Conclusions We conclude that the current risk model for heritable effects of radiation is unsafe. The dose response relationship is non-linear with the greatest effects at the lowest doses. Using Chernobyl data we derive an excess relative risk for all malformations of 1.0 per 10 mSv cumulative dose. The safety of the Japanese A-bomb epidemiology is argued to be both scientifically and philosophically questionable owing to errors in the choice of control groups, omission of internal exposure effects and assumptions about linear dose response.

• The Journal of the Korea Contents Association
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• v.15 no.7
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• pp.578-590
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• 2015

This paper investigated how high school students perceive on nuclear power applying semantic network analysis. The total number of 250 high school students in 6 metropolitan areas responded to the survey. Results indicate that the word which most frequently appeared is 'Nuclear plant' (87 times) following by 'Japan' (71 times), 'Danger'(59 times), 'Fukushima' (59 times), 'Radioactivity' (56 times), 'Energy' (47 times), 'Youngkwang' (37 times), 'Electricity' (30times), 'Chernobyl' (29 times), 'Explosion' (25 times). For students in higher acceptance level of nuclear 'Radioactivity' (25 times) was most frequently showed up following by 'Fukushima' (23 times), 'Energy' (21 times), 'Japan' (21 times), Nuclear plant' (20 times), 'Danger' (17 times), 'Youngkwang' (16 times). For student in lower acceptance level of nuclear, the word of 'Nuclear plant' (40 times) most frequently appeared following by 'Japan' (31 times)', 'Danger' (29 times), 'Fukushima' (23 times), 'Radioactivity' (17 times), 'Energy' (16 times), 'Youngkwang' (16 times), 'Chernobyl' (15 times).