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Shikaze, Yoshiaki; Saito, Kimiaki; Tanimura, Naoki*; Yoshimura, Kazuya; Liu, X.; Machida, Masahiko
Radiation Protection Dosimetry, 201(15), p.1025 - 1042, 2025/09
Times Cited Count：0The two-component model, comprising a fast-decay and a slow-decay component, has been widely used to approximate the decreasing trends of air dose rates in contaminated areas surrounding major nuclear accident sites. However, its adequacy is yet to be thoroughly validated. This study analyzed extensive car-borne survey data collected from 2011 to 2016 after the Fukushima Daiichi Nuclear Power Plant accident using the least absolute shrinkage and selection operator regression with a high-degree-of-freedom model. This analysis aimed to evaluate the adequacy of the two-component model and investigate the profiles of ecological half-lives. Next, future predictions of air dose rate distributions were made using a prediction model formula that incorporated the average ecological half-life profiles calculated for each land-use and initial air dose rate category. Prediction accuracy was verified through comparison with integrated map data, which merge air dose rate datasets obtained using different monitoring methods and represent the most currently reliable source. In this paper, we present the results of the analysis of the above environmental half-life profiles and the evaluation of the predictive model calculations, and discuss the reasons that led to these results.
Cs, and their time dependenceWakiyama, Yoshifumi*; Onda, Yuichi*; Yoshimura, Kazuya; Igarashi, Yasunori*; Kato, Hiroaki*
Journal of Environmental Radioactivity, 210, p.105990_1 - 105990_12, 2019/12
Times Cited Count：23 Percentile：59.15(Environmental Sciences)Taniguchi, Keisuke*; Onda, Yuichi*; Smith, H. G.*; Blake, W.*; Yoshimura, Kazuya; Yamashiki, Yosuke*; Kuramoto, Takayuki*; Saito, Kimiaki
Environmental Science & Technology, 53(21), p.12339 - 12347, 2019/11
Times Cited Count：90 Percentile：94.29(Engineering, Environmental)Ando, Masaki; Yamamoto, Hideaki*; Kanno, Takashi*; Saito, Kimiaki
Journal of Environmental Radioactivity, 190-191, p.111 - 121, 2018/10
Times Cited Count：20 Percentile：49.38(Environmental Sciences)Ambient dose equivalent rates in various environments related to human lives were measured by walk surveys using the KURAMA-II systems from 2013 to 2016 around the Fukushima Dai-ichi Nuclear Power Plant. The dose rate of the locations where the walk survey was performed decreased to about 38% of its initial value in the 42 months, which was beyond that attributable to the physical decay. The air dose rates decreased depending on the level of the evacuation areas, and the decrease was slightly larger in populated areas where humans are active. The comparison of walk survey data with car-borne survey data indicated that the air dose rate varies largely even within a 100 m square area. The dose rates measured by the walk surveys were estimated to be medial of those along roads and those of undisturbed flat ground. The air dose rates measured by the walk surveys decreased quickly compared with the air dose rate from the flat ground measurement.
Saito, Kimiaki; Nagai, Haruyasu; Kinase, Sakae; Takemiya, Hiroshi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 59(6), p.40 - 44, 2017/06
no abstracts in English
Lee, S.; Kimura, Fujio*
Boundary-Layer Meteorology, 101(2), p.157 - 182, 2001/11
Times Cited Count：54 Percentile：74.15(Meteorology & Atmospheric Sciences)no abstracts in English
Onda, Yuichi*; Taniguchi, Keisuke*; Wakiyama, Yoshifumi*; Yoshimura, Kazuya; Smith, H.*; Blake, W.*; Iwagami, Sho*; Kato, Hiroaki*
no journal, ,
Munkhbat, D.*; Kawahigashi, Masayuki*; Battulga, B.; Bolormaa, O.*; Sainjargal, B.*
no journal, ,
