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Moriguchi, Yuichi*; Sato, Yosuke*; Morino, Yu*; Goto, Daisuke*; Sekiyama, Tsuyoshi*; Terada, Hiroaki; Takigawa, Masayuki*; Tsuruta, Haruo*; Yamazawa, Hiromi*
KEK Proceedings 2021-2, p.21 - 27, 2021/12
no abstracts in English
Saito, Kimiaki
Isotope News, (773), p.3 - 6, 2021/02
no abstracts in English
Ji, Y.-Y.*; Ochi, Kotaro; Hong, S. B.*; Nakama, Shigeo; Sanada, Yukihisa; Mikami, Satoshi
Radiation Physics and Chemistry, 179, p.109205_1 - 109205_11, 2021/02
Times Cited Count：7 Percentile：75.12(Chemistry, Physical)In situ gamma-ray spectrometry using diverse survey platforms has been conducted in contaminated areas with several dose rate levels around the Fukushima Daiichi Nuclear Power Plant (FDNPP). Six survey sites, including two evacuation zones around the FDNPP, were selected for ground-based gamma-ray spectrometry using HPGe (high purity Ge) and LaBr
(Ce) detectors to assess the radioactive cesium deposition in the ground. The diverse levels of radioactivity of 
Cs were then distributed to six survey sites from 30 to 3000 kBq m
in the measurement period of October 2018. A method to directly calculate the depth profile using in situ measurement was introduced so as to have representation over a wide area, and the results were successfully compared with those of sample analysis at one point in the site.
Saito, Kimiaki
Tokyo Denryoku Fukushima Daiichi Genshiryoku Hatsudensho Jiko Ni Yoru Kankyo Osen No Kenkyu Chosa No Shinten To Kadai (Internet), p.8 - 10, 2020/07
no abstracts in English
Saito, Kimiaki
Environmental Contamination from the Fukushima Nuclear Disaster; Dispersion, Monitoring, Mitigation and Lessons Learned, p.38 - 43, 2019/09
Times Cited Count：0no abstracts in English
Saito, Kimiaki
Genshiryoku No Ima To Ashita, p.148 - 151, 2019/03
no abstracts in English
Yoshimura, Kazuya
KEK Proceedings 2018-7, p.36 - 40, 2018/11
no abstracts in English
Saito, Kimiaki; Onda, Yuichi*
Journal of Environmental Radioactivity, 139, p.240 - 249, 2015/01
Times Cited Count：53 Percentile：92.73(Environmental Sciences)no abstracts in English
Suga, Shinichi
Shinkokyu Kido Moderu; Gaiyo To Kaisetsu, 0, p.93 - 100, 1995/03
no abstracts in English
Yoshimura, Kazuya
no journal, ,
no abstracts in English
Saito, Kimiaki; Ando, Masaki; Matsuda, Norihiro; Tsuda, Shuichi; Yoshida, Tadayoshi; Mikami, Satoshi
no journal, ,
no abstracts in English
Saito, Kimiaki
no journal, ,
no abstracts in English
Saito, Kimiaki
no journal, ,
no abstracts in English
Mikami, Satoshi; Ishikawa, Daisuke; Nakano, Masakazu; Matsuda, Norihiro; Uno, Kiichiro; Sato, Akane; Matsumoto, Shinichiro; Yamamoto, Hideaki; Saito, Kimiaki
no journal, ,
Distributions of air dose rate and inventory of radioactive cesium deposited on ground were investigated in 2013, within 80-km radial area centered around the Fukushima Daiichi Nuclear Power Plant. We revealed the characteristics of the time-dependent change of the air dose rate and the inventory by comparison with the measurement results of the past investigations.
Yoshimura, Kazuya; Abe, Tomohisa
no journal, ,
Air dose rates in urban areas decrease faster in residential areas than in evacuation zones, suggesting that human activities facilitate the reduction. However, human activities include various factors such as decontamination and road wear caused by traffic. Therefore, it is difficult to evaluate the effect of human activities by conventional analysis using monitoring data, except for the effect of decontamination. This study aims to evaluate the effects of human activities on the reduction. This study has been analyzed using air dose rate monitoring data obtained over a wide area with long-term monitoring, in addition to the field observation and simulation evaluations. In this presentation, an overview of this study and the results of field observations are present.
Saito, Kimiaki; Mikami, Satoshi; Ando, Masaki; Matsuda, Norihiro; Tsuda, Shuichi; Yoshida, Tadayoshi; Yoshimura, Kazuya; Sato, Tetsuro*; Kanno, Takashi; Yamamoto, Hideaki
no journal, ,
no abstracts in English
Saito, Kimiaki
no journal, ,
no abstracts in English
Yoshimura, Kazuya; Saito, Kimiaki; Fujiwara, Kenso
no journal, ,
no abstracts in English
Terada, Hiroaki; Nagai, Haruyasu; Katata, Genki; Tsuzuki, Katsunori; Akari, Shusaku*
no journal, ,
During the Fukushima Daiichi Nuclear Power Station accident which is necessary for accurate estimation of doses to the public, atmospheric dispersion simulations were conducted by using an atmospheric dispersion model underdevelopment Japan Atomic Energy Agency. The simulations were done by a latest meteorological model WRF and a particle dispersion model GEARN which has detailed deposition scheme considering different chemical forms. Surface deposition distribution in east Japan measured by airborne survey was largely reproduced by the simulation using the four-dimensional variational assimilation method (4D-Var) with meteorological observation data near the site and the latest estimated source term. Hereafter, we aim to estimate more accurate source term based on the comparison with the measurements such as air concentrations of Cs, etc.
Cs due to the Fukushima Daiichi Nuclear Power Station accident based on the intercomparison of atmospheric dispersion modelsMorino, Yu*; Kitayama, Kyo*; Takigawa, Masayuki*; Nakajima, Teruyuki*; Hayami, Hiroshi*; Nagai, Haruyasu; Terada, Hiroaki; Saito, Kazuo*; Shimbori, Toshiki*; Kajino, Mizuo*; et al.
no journal, ,
For the evaluation of the validity and variability of atmospheric transport model results, we compared results of seven models submitted for the model inter-comparison project of Science Council of Japan to simulate Cs released from the Fukushima Daiichi Nuclear Power Plant. Model reproducibility was assessed with the observed hourly atmospheric concentrations of Cs in Tohoku and Kanto regions. Among nine plumes from 12 to 21 in March 2011, performance of the models was the best for the plume which dispersed over the Kanto region in 15 March. The models generally reproduced the observed Cs concentrations in plumes which widely spread inland of Tohoku or Kanto regions. By contrast, the models largely underestimated the observed Cs concentrations for the case which passed coastal areas of Japan. Ensemble average of seven models showed reasonable performance for most of plumes, and no individual models reproduced better than the ensemble average.
