• Journal of Radiation Protection and Research
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• v.37 no.2
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• pp.75-83
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• 2012

Marking the first anniversary of the Fukushima nuclear accident, which took place on March 11th, 2011, the level of adolescent awareness and understanding of radiation was surveyed, and the results were then compared with those for adults with the same questionnaires conducted at similar times. A qualitative survey and frequency analysis were made for the design of the study methodology. Those surveyed were limited to 3rd grade middle school students, 15 years of age, who are the future generation. The questionnaire, which is a survey tool, was directly distributed to the students and 2,217 answers were analysed. The questionnaires were composed of 40 questions, and it was found that Cronbach's coefficient was high with 'self awareness of radiation' at 0.494, 'risk of radiation' at 0.843, 'benefit of radiation' at 0.748, 'radiological safety control' at 0.692, 'information sources of radiation' at 0.819, and 'impacts of Fukushima accident'. The results of the survey analysis showed that the students' knowledge of radiation was not very high with 67.4 points (69.5 points for adults) calculated on a maximum scale of 100 points (converted points). The impacts of the Fukushima nuclear accident were found to be less significant to adolescents than adults, and the rate of answer of "so" or " very so" in the following questions demonstrates this well. It was also shown that the impacts of the Fukushima accident to adolescents were comparatively low with 27.0% (38.9% for adults) on the question of "attitude changed against nuclear power due to the Fukushima accident," 65.7%(86.6% for adults) on the question of "the damages from the Fukushima accident was immeasurably huge," and 65.0% (86.3% for adults) on "the Fukushima accident contributed to raising awareness on the safety of nuclear power plants". The adolescents had a high rate of "average" answers on most of the questions compared with adults, and it can be construed that this resulted from adolescent awareness of radiation not being firmly rooted on themselves. This study was the first of its kind for surveying adolescents regarding the level of awareness of radiation after the Fukushima accident, and the results were compared with the survey results of adults, and they are expected to greatly contribute toward establishing a radiation policy by the government in the future.

• Nuclear Engineering and Technology
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• v.45 no.1
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• pp.1-12
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• 2013

This paper describes the radiation doses to human and non-human biota in the Republic of Korea, as a result of the Fukushima nuclear accident. By using the measured airborne activity and ground deposition, the effective and thyroid doses of five human age groups (infant, 5 years, 10 years, 15 years and adult) were estimated by the ECOSYS code, and the whole body absorbed dose rate of the eight Korean reference animals and plants (RAPs) was estimated by the K-BIOTA (the Korean computer code to assess the risk of radioactivity to wildlife). The first-year effective and thyroid human doses ranged from 5.7E-5 mSv in the infant group to 2.0E-4 mSv in the 5 years group, and from 5.0E-4 mSv in the infant group to 3.4E-3 mSv in the 5 years group, respectively. The life-time (70 years) effective and thyroid human doses ranged from 1.5E-4 mSv in the infant group to 3.0E-4 mSv in the 5 years group, and from 6.0E-4 mSv in the infant group to 3.5E-3 mSv in the 5 years group, respectively. The estimated maximum whole body absorbed dose rate to the Korean RAPs was 6.7E-7 mGy/d for a snake living in soil (terrestrial biota), and 2.0E-5 mGy/d for freshwater fish (aquatic biota), both of which were far less than the generic dose criteria to protect biota from ionizing radiation. Also, the screening level assessment for ERICA's (Environmental Risks from Ionizing Contaminants: Assessments and management) limiting organisms showed that the risk quotient (RQ) for the estimated maximum soil and water activity was significantly less than unity for both the terrestrial and freshwater organisms. Conclusively, the radiological risk of the radioactivity released into the environment by the Fukushima nuclear accident to the public and the non-human biota in the republic of Korea is considered negligible.

• Journal of Radiation Protection and Research
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• v.46 no.3
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• pp.134-142
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• 2021

Background: From 2018 to 2020, the Expert Study on Public Understanding after the Fukushima Daiichi Nuclear Power Plant Accident (the Expert Study Group) identified and analyzed activities designed to promote public understanding of science and radiation since the Fukushima accident, and held discussions on how to achieve public understanding in the situation where public confidence has been lost, and how experts should prepare for dealing with the public. This panel session was held at the 53^rd meeting of the Japan Health Physics Society on June 30, 2020. Materials and Methods: First, three subgroup (SG) leaders reported their research methods and results. Then, two designated speakers, who participated as observers of the Expert Study Group, commented on the activities. Next, the five speakers held a panel discussion. Finally, the rapporteur summarized. Results and Discussion: SG leaders presented reports from researchers and practitioners in health physics and environmental risks who provided information after the Fukushima accident. During the discussion, experts in sociology and ethics discussed the issues, focusing on the overall goals of the three groups, local (personal) and mass communication, and ethical values. Many of the activities instituted by the experts after the accident were aimed at public understanding of science (that is, to provide knowledge to residents), but by taking into account interactions with residents and their ethical norms, the experts shifted to supporting the residents' decision-making through public engagement. The need to consider both content and channels is well known in the field of health communication, and overlaps with the above discussion. Conclusion: How to implement and promote the public engagement in society was discussed in both the floor and designated discussions. Cooperation between local communities and organizations that have already gained trust is also necessary in order to develop relationships with local residents in normal times, to establish an information transmission system, and to make it work effectively.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2960-2973
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• 2022

Since Fukushima nuclear power plant (NPP) accident in 2011, the importance of research on various severe accident phenomena has been emphasized. Particularly, detailed analysis of combustion risk is necessary following the containment damage caused by combustion in the Fukushima accident. Many studies have been conducted to evaluate the risk of local hydrogen concentration increases and flame propagation using computational code. In particular, the potential for combustion by local hydrogen concentration in specific areas within the containment has been emphasized. In this study, the process of flame propagation generated inside a reactor core to containment during a loss of coolant accident (LOCA) was analyzed using MELCOR 2.1 code. Later in the LOCA scenario, it was expected that hydrogen combustion occurred inside the reactor core owing to oxygen inflow through the cold leg break area. The main driving force of the oxygen intrusion is the elevated containment pressure due to the molten corium-concrete interaction. The thermal and mechanical loads caused by the flame threaten the integrity of the containment. Additionally, the containment spray system effectiveness in this situation was evaluated because changes in pressure gradient and concentrations of flammable gases greatly affect the overall behavior of ignition and subsequent containment integrity.

• Nuclear Engineering and Technology
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• v.47 no.1
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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.

• The Journal of the Korea Contents Association
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• v.13 no.9
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• pp.281-287
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• 2013

Based on surveys of Busan residents, this study aimed to analyze general perception: radiation knowledge, recognition of the standard of knowledge, radiation benefits, recognition of the risks of nuclear power, collection of information on the Fukushima nuclear accident, recognition of changes before and after the Fukushima nuclear accident, and the path of collecting information about nuclear power and radiation. This analysis was based on 414 people who reside in Busan metropolitan city. It has been found that the Busan metropolitan city residents acknowledged the necessity of radiation in principle, however, most have negative awareness relating to safety. It is assumed that this negative awareness is a result from past nuclear power plant accidents, rather than being based on their own knowledge of radiation. Therefore, it is considered that efforts to change people's awareness necessitate education of the public. This can be done via media, widening the range of people's knowledge, and furthermore, promoting changes within people's awareness and perspectives.

• Journal of Radiation Protection and Research
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• v.37 no.1
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• pp.1-9
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• 2012

A year has passed since the nuclear power plant accident in Fukushima on March 11, 2011, and a survey for public perception on radiation by Korean people has been made. The methodological design was based on a quantitative survey and a frequency analysis was done. The analysis objects were survey papers (n=2,754pcs) answered by random ordinary citizens chosen from all over the country. The questionnaires, and study tool, were directly distributed and collected. A total of 40 questionnaires using a coefficient of Cronbach's ${\alpha}$ per each area was 'self perception of radiation' (0.620), 'radiation risk' (0.830), 'benefit from radiation' (0.781), 'radiation controlled' (0.685), 'informative source of radiation' (0.831), 'influence degree from Fukushima accident' (0.763), showing rather high score from all areas. As the result of the questionnaires, the knowledge of radiation concept was 69.50 out of 100 points, which shows a rather significant difference from the result of 'know well about radiation' (53.7%) and 'just know about radiation' (37.40%). According to the survey, one of the main reasons why radiation seems risky was that once exposed to radiation, it may not have negative impacts presently but, the next generation could see negative impacts (66.1%). About 41% of our respondents showed a negative position against the government's report on radiation while 39.5% of respondents said that we should stop running nuclear power in light of Fukushima nuclear power plant accident. This study was done for the first time by Korean people's public perception on radiation after the Fukushima nuclear power plant accident. We expect this might have significant contributions to the establishment of the government's policy on radiation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.331-336
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• 2011

When the Fukushima nuclear power plant accident occurred in March, a hydrogen explosion in the reactor building at the 4th unit of Fukushima plants lead to a big surprise because the full core of the unit 4 reactor had been moved and stored underwater at the spent nuclear fuel storage pool for periodic maintenance. It was because the potential criticality in the fuel storage pool by coolant loss may yield more severe situation than the similar accident happened inside the reactor vessel. In the paper, the safety state of the spent fuel storage pool and rack structures of the domestic nuclear plants would be reviewed and compared with the Fukushima plant case by engineering viewpoint of potential severe accidents.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.133-140
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• 2016

Backgrounds: The accident at Fukushima Daiichi Nuclear Power Plant (NPP), March 2011, caused serious radioactive contamination over wide area in east Japan. Therefore, it is important to know the effect of the accident and the status of NPP. Materials and Methods: This paper provides a review on the status of radiation dose and radioactive contamination caused by the accident on the basis of publicized information. Results and Discussion: Monitoring of radiation dose and exposure dose of residents has been conducted extensively by the governments and various organizations. The effective dose of general residents due to the accident proved to be less than a mSv both for external and internal dose. The equivalent committed dose of thyroid was evaluated to be a few mSv in mean value and less than 50 mSv even for children. Monitoring of radioactivity concentration has been carried out on food ingredients, milk and tap water, and actual meal. These studies indicated the percentage of foods above the regulation standard was over 10% in 2011 but decreasing steadily with time. The internal dose due to foods proved to be tens of ${\mu}Sv$ and much less than that due to natural $^{40}K$ even in the Fukushima area and decreasing steadily, although high level concentration is still observed in wild plants, wild mushrooms, animals and some kind of fishes. Conclusion: According to extensive studies, not only the effect of the accident but also the pathway and countermeasures against radioactive contamination have been revealed, and they are applied very effectively for restoration of environment and reconstruction of the area.

• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.117-124
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• 2013

Objective: This paper presents additional considerations related to organization and safety culture extracted from recent human error incidents in Korea, such as station blackout(i.e., SBO) in Kori#1. Background: Safety culture has been already highlighted as a major cause of human errors after 1986 Chernobyl accident. After Fukushima accident in Japan, the public acceptance for nuclear energy has taken its toll. Organizational characteristics and culture became elucidated as a major contributor again. Therefore many nuclear countries are re-evaluating their safety culture, and discussing any preparedness and its improvement. On top of that, there was an SBO in 2012 in the Kori#1. Korean public feels frustrated due to the similar human errors causing to a catastrophe like Fukushima accident. Method: This paper reassesses Japan's incidents, and revisits Korea's recent incidents. It focuses on the analysis of the hazards rather than the causes of human errors, the derivation of countermeasures, and their implementation. The preceding incidents and conclusions from Japanese experience are also re-analyzed. The Fukushima accident was an SBO due to the natural disaster such as earthquakes and a successive tsunami. Unlike the Fukushima accident, the Kori#1 incident itself was simple and restored without any loss and radioactive release. However, the fact that the incident was deliberately concealed led to massive distrust. Moreover, the continued violation of rules and organized concealment of the accident are serious signs of a new distorted type of human errors, blatantly revealing the cultural and fundamental weakness of the current organization. Result: We should learn from Japanese experiences who had taken pride in its safety technology and fairly high confidence in safety culture. Japan's first criticality accident in JCO facility splashed cold water on that confidence. It has turned out to be a typical case revealing the problems in the organization and safety culture. Since Japan has failed to gain lessons and countermeasure, the issue persists to the Fukushima incident. Conclusion: Safety culture is not a specific independent element, which makes it difficult to either evaluate it properly or establish countermeasures from the lessons. It may continue to expose similar human errors such as concealment of incident and manipulation of bad data. Application: Not only will this work establish the course of research for organization and safety culture, but this work will also contribute to the revitalization of Korea's nuclear industry from the disappointment after the export contract to UAE.