• Journal of Radiation Protection and Research
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• v.46 no.2
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• pp.66-79
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• 2021

Background: The Japan Atomic Energy Agency (JAEA) is specified in the Disaster Counter-measures Basic Act as a designated public corporation for dealing with nuclear disasters. Materials and Methods: The Nuclear Emergency Assistance and Training Center (NEAT) was established in 2002 as the activity base providing technical assistance to both national and local governments during nuclear emergencies. The NEAT has a robust structure and utilities and special installations, and it organizes training and exercises. Results and Discussion: Due to an offshore earthquake that caused a devastating tsunami in March 2011, a nuclear accident occurred at the Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Station. The NEAT responded by conducting off-site environmental radiation monitoring and contamination screening, dispatching special vehicles, offering telephone consultations, and calculating the dispersion of radioactive materials. An examination of the emergency response activities revealed that the organization was prepared for these types of disasters and was able to plan long-term response. Conclusion: As a designated public corporation, the JAEA technically supports the national government, the Fukushima prefectural government, and the Ibaraki prefectural government, all of which responded to the off-site emergencies resulting from the March 2011 Fukushima Daiichi accident

• Journal of Radiation Protection and Research
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• v.46 no.4
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• pp.184-193
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• 2021

Background: The radionuclides released by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident 9 years ago are still being monitored by various research teams and the Japanese government. Comparison of different surveys' results could help evaluate the exposure doses and the mechanism of radiocesium behavior in the urban environment in the area. In this study, we clarified the relationship between land use and temporal changes in the ambient dose rates (air dose rates) using big data. Materials and Methods: We set a series of 1 × 1 km² meshes within the 80 km zone of the FDNPP to compare the different survey results. We then prepared an analysis dataset from all survey meshes to analyze the temporal change in the air dose rate. The selected meshes included data from all survey types (airborne, fixed point, backpack, and carborne) obtained through the all-time survey campaigns. Results and Discussion: The characteristics of each survey's results were then evaluated using this dataset, as they depended on the measurement object. The dataset analysis revealed that, for example, the results of the carborne survey were smaller than those of the other surveys because the field of view of the carborne survey was limited to paved roads. The location factor of different land uses was also evaluated considering the characteristics of the four survey methods. Nine years after the FDNPP accident, the location factor ranged from 0.26 to 0.49, while the half-life of the air dose rate ranged from 1.2 to 1.6. Conclusion: We found that the decreasing trend in the air dose rate of the FDNPP accident was similar to the results obtained after the Chernobyl accident. These parameters will be useful for the prediction of the future exposure dose at the post-accident.

• Journal of Radiation Protection and Research
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• v.47 no.2
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• pp.67-76
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• 2022

Background: We conducted a cross-sectional study of residents within and outside Fukushima Prefecture to clarify their perceptions of the need for smartphone applications (apps) for explaining exposure doses. The results will lead to more effective methods for identifying target groups for future app development by researchers and municipalities, which will promote residents' understanding of radiological situations. Materials and Methods: In November 2019, 400 people in Fukushima Prefecture and 400 people outside were surveyed via a web-based questionnaire. In addition to basic characteristics, survey items included concerns about radiation levels and intention to use a smartphone app to keep track of exposure. The analysis was conducted by stratifying responses in each region and then cross-tabulating responses to concerns about radiation levels and intention to use an app by demographic variables. The intention to use an app was analyzed by binomial logistic regression analysis. Text-mining analyses were conducted in KH Coder software. Results and Discussion: Outside Fukushima Prefecture, concerns about the medical exposure of women to radiation exceeded 30%. Within the prefecture, the medical exposure of women, purchasing food products, and consumption of own-grown food were the main concerns. Within the prefecture, having children under the age of 18, the experience of measurement, and having experience of evacuation were significantly related to the intention to use an app. Conclusion: Regional and individual differences were evident. Since respondents differ, it is necessary to develop and promote app use in accordance with their needs and with phases of reconstruction. We expect that a suitable app will not only collect data but also connect local service providers and residents, while protecting personal information.

• Journal of Radiation Protection and Research
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• v.47 no.2
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• pp.77-85
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• 2022

Background: After the Fukushima Daiichi Nuclear Power Station (FDNPS) accident, a model was developed to estimate the external exposure doses for residents who were expected to return to their homes after evacuation orders were lifted. However, the model's accuracy and uncertainties in parameters used to estimate external doses have not been evaluated. Materials and Methods: The model estimates effective doses based on the integrated ambient dose equivalent (H^*(10)) and life patterns, considering a dose reduction factor to estimate the indoor H^*(10) and a conversion factor from H^*(10) to the effective dose. Because personal dose equivalent (H_p(10)) has been reported to agree well with the effective dose after the FDNPS accident, this study validates the model's accuracy by comparing the estimated effective doses with H_p(10). The H_p(10) and life pattern data were collected for 36 adult participants who lived or worked near the FDNPS in 2019. Results and Discussion: The estimated effective doses correlated significantly with H_p(10); however, the estimated effective doses were lower than H_p(10) for indoor sites. A comparison with the measured indoor H^*(10) showed that the estimated indoor H^*(10) was not underestimated. However, the H_p(10) to H^*(10) ratio indoors, which corresponds to the practical conversion factor from H^*(10) to the effective dose, was significantly larger than the same ratio outdoors, meaning that the conversion factor of 0.6 is not appropriate for indoors due to the changes in irradiation geometry and gamma spectra. This could have led to a lower effective dose than H_p(10). Conclusion: The estimated effective doses correlated significantly with H_p(10), demonstrating the model's applicability for effective dose estimation. However, the lower value of the effective dose indoors could be because the conversion factor did not reflect the actual environment.

• 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.

• The Journal of Fisheries Business Administration
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• v.43 no.2
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• pp.27-39
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• 2012

The purpose of this study lies in analyzing the effects of Fukushima nuclear plant incident, due to the earthquake in the northeastern part of Japan, on South Korean consumers'responses to domestic marine products. Survey results show that the response to the event by all consumers is not significant, but not by individual consumer. Empirical results show that if consumers are relatively more interested in health issues, if they consume mollusca relatively more among marine products and if they are with children under the age of 14, they increased the consumption of domestic marine products while decreased that of Japanese seafood. On the contrary, if consumers take shellfish products relatively more among seafood, they reduced the consumption of domestic marine products as well as Japanese ones.

• 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.

• Nuclear Engineering and Technology
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• v.45 no.1
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• pp.13-20
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• 2013

This paper looks at the Fukushima disaster from the perspective of resilience engineering, which replaces a search for causes with an understanding of how the system failed in its performance. Referring to the four resilience abilities of responding, monitoring, learning, and anticipating, the paper focuses on how inadequate engineering anticipation or risk assessment during the design, in combination with inadequate response capabilities, precipitated the disaster. One lesson is that systems such as nuclear power plants are complicated, not only in how they function during everyday or exceptional conditions, but also during their whole life cycle. System functions are intrinsically coupled synchronically and diachronically in ways that may affect the ability to respond to extreme conditions.

• STI Policy Review
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• v.4 no.1
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• pp.135-161
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• 2013

This paper examines Japan's Science and Technology (S&T) Basic Plans in accordance with its S&T Basic Law. The Basic Plans promote two major innovation (Green Innovation and Life Innovation) towards the creation of new markets and jobs, specifically under the Fourth S&T Basic Plan enacted on August 2011. Successful smart community demonstration projects at four urban localities were launched under plans to promote Green Innovation research and development of renewable energy technologies. However, the expectation that renewable energy such as solar or wind power can replace nuclear power is not backed by sufficient evidence. Furthermore, the electricity produced by these sources is expensive and unstable owing to its reliance on weather conditions. The Fukushima nuclear power plant accident on March 2011 has also seriously affected Japan's future energy plans. According to a government estimate, electricity charges would double if nuclear power generation were abandoned, imposing a heavy burden on the Japanese economy. Japan is in need of energy policies designed on the basis of more far-sighted initiatives.

• Journal of Radiation Protection and Research
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• v.39 no.2
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• pp.103-108
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• 2014

Following the emergency work in Fukushima Daiichi nuclear power plant, more attention was paid for the radiation protection of workers working under severe accident condition. The protection procedure for the emergency workers, including the on-site emergency center, the seismic isolated building and the reestablishment of the radiation protection framework were analyzed to investigate drawbacks and deficiencies which led to adverse effects on the emergency planning and on emergency workers' health and comfort. Those drawbacks were identified and studied, and then suggestions were made to enhance the emergency working condition to avoid any future problems during severe accident emergency work and management.