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Niizato, Tadafumi; Kamikawa, Tsutomu*; Oki, Noriko*
Joho Chishitsu, 35(4), p.99 - 108, 2024/12
Extraction of the needs related to countermeasures against radioactive contamination was conducted by access analysis of the "Base Information Q&A Site" operated by JAEA and text mining of stenographic text data from a briefing on R&D by JAEA for local government officials. The results of the access analysis indicated that even after over 10 years had passed since the 1F accident, there were needs for data and information on the concentration of radiocesium in the environment, and agricultural, forestry, and fishery products and air dose rates used as a degree of radioactive contamination and evidence for the lifting of evacuation orders. The text mining results suggested the needs for data and information on radiocesium concentrations and air dose rates for river systems and aquatic products in the northern part of Hamadori, for forested environment and forest products in Nakadori, and for decontamination and air dose rates in forests and reservoirs in the southern part of Hamadori, as well as for monitoring data on changes in air dose rates after decontamination. The needs for information and data based on surveys and monitoring on the current situation of radioactive contamination rather than the future situation were also inferred.
Gunji, Satoshi; Araki, Shohei; Izawa, Kazuhiko; Suyama, Kenya
Proceedings of International Conference on Physics of Reactors (PHYSOR 2024) (Internet), p.227 - 236, 2024/04
It is considered that a large amount of fuel debris was generated in the TEPCO's Fukushima Daiichi Nuclear Power Station accident. In particular, the criticality characteristics of the fuel debris, including concrete components, which are products of molten core-concrete interaction (MCCI), have not been well investigated. In this study, to plan physical simulation in critical experiments at the critical assembly using pseudo fuel debris samples including concrete, we evaluated the sensitivity to the effective multiplication factor of the Si and Ca cross sections in the concrete-simulant sample based on the results of elemental analysis of the prototype. These sensitivity calculations were carried out for each sample loading method and composition. We focused on the energy profile of the sensitivity of the 
Ca capture reaction and confirmed that the shape of the sensitivity energy profile changed depending on the sample compositions and neutron moderation conditions. We could know the characteristics of each experimental method by clarifying the trends of sensitivity obtained in different experimental cases. It was found that increasing the amount of concrete in the samples and changing the neutron moderation conditions in the experimental core configurations produced similar changes in the shape of the sensitivity energy profile. This result shows the possibility of reproducing the characteristics of MCCI products through practical critical experiments using concrete materials that do not contain fissile materials.
Nuclear Emergency Assistance and Training Center
JAEA-Review 2023-026, 54 Pages, 2023/12
JAEA-Review-2023-026.pdf:3.26MB
The Japan Atomic Energy Agency (JAEA) is one of the designated public corporations, which is the agency dealing with emergency situations in cooperation with the Japanese and local governments under the Disaster Countermeasures Basic Act and under the Armed Attack Situation Response Law. JAEA has, therefore, responsibilities of providing technical assistances to the Japanese and local governments in case of nuclear or radiological emergencies based on these acts. To fulfill the assistances, the JAEA has prepared the Nuclear Emergency Support Measures Regulation, Disaster Prevention Work Plan and Civil Protection Work Plan. The Nuclear Emergency Assistance and Training Center (NEAT) is the main center of the technical assistance in case of emergency, and dispatches experts of JAEA, supplies equipment and materials and gives technical advice and information, to the Japanese and local governments for emergency based on the regulation and plans. In normal time, the NEAT provides the technical assistances such as the exercises and training courses concerning the nuclear preparedness and response to the JAEA experts and to emergency responders including the Japanese and local government officers. This report introduces the results of activities in Japanese Fiscal Year 2022, conducted by the NEAT.
Okuno, Hiroshi; Kawakami, Takeshi; Watanabe, Fumitaka; Horikoshi, Hidehiko*
Journal of Disaster Research, 18(8), p.911 - 917, 2023/12
In response to residents' concerns about the radiation health effects following the nuclear accidents at the Fukushima Daiichi Nuclear Power Station of the Tokyo Electric Power Company in March 2011, the Japan Atomic Energy Agency (JAEA) established a telephone consultation system. Eight toll-free telephone lines were prepared, and employees with knowledge of radiation health effects were assigned for consultation. Approximately 35,000 consultations were conducted from March 17, 2011, to September 18, 2012. The results of the text mining analysis revealed that the greatest source of anxiety was the impact on children's health from radiation. The JAEA's system for telephone consultation was improved following this telephone consultation experience. The description of telephone hotlines in the International Atomic Energy Agency (IAEA) guide, GSG-14, was discussed for further improvements of the JAEA's telephone consultation system.
Nuclear Emergency Assistance and Training Center
JAEA-Review 2022-044, 58 Pages, 2022/12
JAEA-Review-2022-044.pdf:3.83MB
The Japan Atomic Energy Agency (JAEA) is one of the designated public corporations, which is the agency dealing with emergency situations in cooperation with the Japanese and local governments under the Disaster Countermeasures Basic Act and under the Armed Attack Situation Response Law. JAEA has, therefore, responsibilities of providing technical assistances to the Japanese and local governments in case of nuclear or radiological emergencies based on these acts. To fulfill the assistances, the JAEA has prepared the Nuclear Emergency Support Measures Regulation, Disaster Prevention Work Plan and Civil Protection Work Plan. The Nuclear Emergency Assistance and Training Center (NEAT) is the main center of the technical assistance in case of emergency, and dispatches experts of JAEA, supplies equipment and materials and gives technical advice and information, to the Japanese and local governments for emergency based on the regulation and plans. In normal time, the NEAT provides the technical assistances such as the exercises and training courses concerning the nuclear preparedness and response to the JAEA experts and to emergency responders including the Japanese and local government officers. This report introduces the results of activities in Japanese fiscal year 2021, conducted by the NEAT.
Nuclear Emergency Assistance and Training Center
JAEA-Review 2021-039, 98 Pages, 2021/12
JAEA-Review-2021-039.pdf:5.99MB
Japan Atomic Energy Agency (JAEA) is one of the designated public corporations, dealing with emergency situations in cooperation with the Japanese government under the Disaster Countermeasures Basic Act and under the Armed Attack Situation Response Law. JAEA provides technical assistances to the government in case of nuclear or radiological emergencies. JAEA has prepared the Nuclear Emergency Support Measures Regulation, Disaster Prevention Work Plan and Civil Protection Work Plan. Nuclear Emergency Assistance and Training Center (NEAT) is the main center of the technical assistance in case of emergency, and dispatches experts, supplies equipment and materials and gives technical advice to the government. Moreover, NEAT provides the technical exercises and training courses concerning the nuclear emergency preparedness and response to emergency responders. This report introduces the results of activities in FY 2020, during the third medium and long-term plan from FY 2015 to 2021 as Chapter 1. Chapter 2 summarizes activities in 20 years since FY 1999.
Niizato, Tadafumi; Sasaki, Yoshito; Watanabe, Takayoshi; Amamiya, Hiroki*
Dai-31-Kai Shakai Chishitsugaku Shimpojiumu Rombunshu, p.19 - 22, 2021/11
A three-year monitoring of 
Cs outflow associated with soil erosion from decontaminated and burnt sites using an experimental plot was conducted in a mountainous forest of Fukushima, Japan. Corresponding with recovery of the forest floor cover, such as undergrowth and litter layer, the Cs outflow during the monitoring period in the rainy season of Fukushima decreased from 3.24% to 0.61% and 2.79% to 0.03% in the decontaminated and burnt sites, respectively. The forest floor cover ratio of 60% or more is a threshold for an effect on the Cs outflow in the monitoring sites. In the burnt site, a change of dominant outflowed materials from soil particles into litter and its fragments also contributes to the decreasing in the Cs outflow. A protective function of forest floor cover against the soil erosion inherent in the natural forest environment is effective for the migration control of the Cs outflow.
Nuclear Emergency Assistance and Training Center
JAEA-Review 2020-016, 67 Pages, 2020/09
JAEA-Review-2020-016.pdf:4.09MB
The Japan Atomic Energy Agency (JAEA) is one of the designated public institutions, which is an agency dealing with an emergency situation in cooperation with the Japanese and local governments under the Disaster Countermeasures Basic Act and under the Armed Attack Situation Response Law. JAEA has, therefore, responsibilities of providing technical assistances to the Japanese and local governments in case of nuclear or radiological emergencies based on these Acts. To fulfill the assistances, the JAEA has prepared the Nuclear Emergency Support Measures Regulation, Disaster Prevention Work Plan and Civil Protection Work Plan. The Nuclear Emergency Assistance and Training Center (NEAT) is the main center of the technical assistance in case of emergency, and dispatches experts of JAEA, supplies equipment and materials and gives technical advice and information, to the Japanese and local governments for emergency based on the regulation and plans. In normal time, the NEAT provides the technical assistances such as the exercises and training courses concerning the nuclear preparedness and response to the JAEA experts and also to emergency responders including the Japanese and local government officers. This report introduces the results of activities in Japanese Fiscal Year 2019, conducted by NEAT in accordance with the third medium and long-term plan for the period from Japanese Fiscal Year 2015 to 2021.
Kumazaki, Yui
Senmon Toshokan, (278), p.40 - 43, 2016/07
no abstracts in English
Niizato, Tadafumi; Sasaki, Yoshito; Watanabe, Takayoshi; Ito, Satomi; Amamiya, Hiroki*
no journal, ,
no abstracts in English
Kim, M.; Malins, A.; Machida, Masahiko; Yoshimura, Kazuya; Yoshida, Hiroko*; Saito, Kimiaki
no journal, ,
no abstracts in English
Kim, M.; Malins, A.; Yoshimura, Kazuya; Machida, Masahiko; Saito, Kimiaki; Yoshida, Toru*; Yanagi, Hideaki*; Hasegawa, Yukihiro*; Yoshida, Hiroko*
no journal, ,
no abstracts in English
Niizato, Tadafumi; Sasaki, Keiichi*; Koizumi, Yukiko*; Jia, H.*; Okino, Ryo*
no journal, ,
In this paper, we present the temporal changes of Cs-137 depth distributions in forest floor of the evergreen coniferous forests in Fukushima by applying of a cluster analysis to the Cs-137 depth distribution in the forest floor obtained annually about 70-80 points from 2014 to 2020. The results show the temporal changes in the Cs-137 amount decreasing in the litter layer and increasing in the soil layer as a general trend. However, the progress of the Cs migration from the litter to soil layer is distinctly different in each investigation site.
Oba, Kyoko; Yanase, Noboru*; Matsui, Ryota*
no journal, ,
This report is the content of a discussion held at Fukushima National College of Technology with reference to the Deliberative Poll on the theme of ALPS treated water generated by the decommissioning of the Fukushima Daiichi Nuclear Power Station accident of Tokyo Electric Power Company.
Cs/Cs isotopic ratio in environmental samplesShimada, Asako; Nomura, Masao*; Tsukahara, Takehiko*; Takeda, Seiji
no journal, ,
Although identification of radiocesium in environmental samples is commonly performed by using 
Cs/Cs radioactivity ratio, measurement of Cs will become challenge in a few decade ago because of short half-life (2 y). Instead of the measurement of Cs/Cs radioactivity ratio, the measurement of Cs/Cs isotopic ratio will be effective in future because of long half-life of Cs (133 My). In order to measure Cs/Cs isotopic ratio, Cs must be separated from the matrix of soil. Since 1 Bq of Cs is equal to 312.5 fg, large amount of soil have to be treated to extract Cs for the measurement. In the present study, we improved chemical separation method using BOBCalixC6 by optimizing extraction time and reuse of the organic phase. Finally, approximately 170 g of soil sampled at Toka-mura was dissolved and Cs was separate with the developed method to measure Cs/Cs isotopic ratio.
Niizato, Tadafumi; Sasaki, Yoshito; Amamiya, Hiroki*; Yoshida, Kaori
no journal, ,
no abstracts in English
Niwano, Yuma*; Kato, Hiroaki*; Akaiwa, Satoru*; Anderson, D.*; Iida, Hikaru*; Nakanishi, Miyu*; Onda, Yuichi*; Sato, Hikaru*; Niizato, Tadafumi
no journal, ,
Oba, Kyoko; Yanase, Noboru*; Suzuki, Shigekazu*
no journal, ,
This research is based on the Method of Deliberative Poll regarding Discussion on ALPS Treated Water and Soil from Off site Decontamination Work, which has become a problem due to the decommissioning of the TEPCO Fukushima Daiichi Nuclear Power Plant accident, which is being conducted at universities and national colleges of technology. With an education in mind, the project trains moderators and reporters for group discussions, which are important in discussions. We are also experimenting with an implementation method that includes humanities students and includes on-site visits. We will present the possibilities of education based on the Method of Deliberative Poll.
Atsumi, Reika*; Niizato, Tadafumi; Takeuchi, Shinji*; Amamiya, Hiroki*
no journal, ,
no abstracts in English
Niizato, Tadafumi; Kamikawa, Tsutomu*; Oki, Noriko*
no journal, ,
Extraction of the needs related to countermeasures against radioactive contamination was conducted by access analysis of the "Base Information Q&A" site operated by Japan Atomic Energy Agency (JAEA) and text mining of stenographic text data from a briefing on Research and Development by JAEA for local government officials. The results indicated that even after more than 10 years had passed since the Fukushima Daiichi Nuclear Power Plant accident, there were needs for data and information on the concentration of radiocesium in the environment, and agricultural, forestry, and fishery products and air dose rates used as a degree of radioactive contamination and evidence for the lifting of evacuation orders. The text mining results suggested the needs for data and information on radiocesium concentrations and air dose rates for river systems and aquatic products in the northern part of Hamadori on the Pacific coast, for forested environment and forest products in Nakadori of an inland basin. The needs for information and data based on surveys and monitoring on the current situation of radioactive contamination rather than the future situation were also inferred.
