Watershed-geochemical model to simulate dissolved and particulate Cs discharge from a forested catchment

Sakuma, Kazuyuki; Hayashi, Seiji*; Yoshimura, Kazuya; Kurikami, Hiroshi; Malins, A.; Funaki, Hironori; Tsuji, Hideki*; Kobayashi, Takamaru*; Kitamura, Akihiro; Iijima, Kazuki

Water Resources Research, 58(8), p.e2021WR031181_1 - e2021WR031181_16, 2022/08

https://doi.org/10.1029/2021WR031181

Present status and future perspective of R&D for 3D-ADRES (3-Dimensional Air Dose Rate Evaluation System); Evaluation scheme for air dose rate distributions in city and forest areas towards Fukushima's revitalization

Kim, M.; Malins, A.; Machida, Masahiko; Yoshimura, Kazuya; Saito, Kimiaki; Yoshida, Hiroko*; Yanagi, Hideaki*; Yoshida, Toru*; Hasegawa, Yukihiro*

RIST News, (67), p.3 - 15, 2021/09

https://www.rist.or.jp/rnews/67/ristnews_67.html

no abstracts in English

Calculations for ambient dose equivalent rates in nine forests in eastern Japan from Cs and Cs radioactivity measurements

Malins, A.; Imamura, Naohiro*; Niizato, Tadafumi; Takahashi, Junko*; Kim, M.; Sakuma, Kazuyuki; Shinomiya, Yoshiki*; Miura, Satoru*; Machida, Masahiko

Journal of Environmental Radioactivity, 226, p.106456_1 - 106456_12, 2021/01

https://doi.org/10.1016/j.jenvrad.2020.106456

Status of study of long-term assessment of transport of radioactive contaminants in the environment of Fukushima (FY2018) (Translated document)

Nagao, Fumiya; Niizato, Tadafumi; Sasaki, Yoshito; Ito, Satomi; Watanabe, Takayoshi; Dohi, Terumi; Nakanishi, Takahiro; Sakuma, Kazuyuki; Hagiwara, Hiroki; Funaki, Hironori; et al.

JAEA-Research 2020-007, 249 Pages, 2020/10

JAEA-Research-2020-007.pdf:15.83MB

The accident of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. occurred due to the Great East Japan Earthquake, Sanriku offshore earthquake, of 9.0 magnitude and the accompanying tsunami. As a result, large amount of radioactive materials was released into the environment. Under these circumstances, Japan Atomic Energy Agency (JAEA) has been conducting "Long-term Assessment of Transport of Radioactive Contaminants in the Environment of Fukushima" concerning radioactive materials released in environment, especially migration behavior of radioactive cesium since November 2012. This report is a summary of the research results that have been obtained in environmental dynamics research conducted by JAEA in Fukushima Prefecture.

Kinetic inductance neutron detector operated at near critical temperature

Vu, TheDang; Nishimura, Kazuma*; Shishido, Hiroaki*; Harada, Masahide; Oikawa, Kenichi; Miyajima, Shigeyuki*; Hidaka, Mutsuo*; Oku, Takayuki; Soyama, Kazuhiko; Aizawa, Kazuya; et al.

Journal of Physics; Conference Series, 1590, p.012036_1 - 012036_9, 2020/07

https://doi.org/10.1088/1742-6596/1590/1/012036

Simulation study of the effects of buildings, trees and paved surfaces on ambient dose equivalent rates outdoors at three suburban sites near Fukushima Dai-ichi

Kim, M.; Malins, A.; Yoshimura, Kazuya; Sakuma, Kazuyuki; Kurikami, Hiroshi; Kitamura, Akihiro; Machida, Masahiko; Hasegawa, Yukihiro*; Yanagi, Hideaki*

Journal of Environmental Radioactivity, 210, p.105803_1 - 105803_10, 2019/12

https://doi.org/10.1016/j.jenvrad.2018.09.001

To improve the accuracy of simulations for air dose rates over fallout contaminated areas, the distribution of the radionuclides within the environment should be modelled realistically, e.g. considering differences in radioactivity levels between agricultural land, urban surfaces, and forest compartments. Moreover simulations should model the shielding of rays by buildings, trees and land topography. Here we outline a system for generating three dimensional models of urban and rural areas in Fukushima Prefecture. The Cs and Cs radioactivity distribution can be set flexibly across the different components of the model. The models incorporate realistic representations of local buildings, based on nine common Japanese designs, individual conifer and broadleaf trees, and the topography of the land surface. Models are generated from Digital Elevation Model (DEM) and Digital Surface Model (DSM) datasets, and refined by users assisted with ortho-photographs of target sites. Completed models are exported from the system in a format suitable for the Particle and Heavy Ion Transport code System (PHITS) for the calculation of air dose rates and other radiological quantities. The system is demonstrated by modelling a suburban area 4 km from the Fukushima Daiichi Nuclear Power Plant that has yet to be decontaminated. Air dose rates calculated in PHITS were correlated with measurements taken across the site in a car-borne survey.

Research and development behind a computation system for 3D distributions of air dose rates in the environment; Estimating environmental radiation doses using PHITS together with remote sensing data

Kim, M.; Malins, A.; Sakuma, Kazuyuki; Kitamura, Akihiro; Machida, Masahiko; Hasegawa, Yukihiro*; Yanagi, Hideaki*

Isotope News, (765), p.30 - 33, 2019/10

https://www.jrias.or.jp/books/cat3/2019/765.html

Here we outline a system for generating three dimensional models of urban and rural areas in Fukushima Prefecture. The Cs and Cs radioactivity distribution can be set flexibly across the different components of the model. The models incorporate realistic representations of local buildings, individual conifer and broadleaf trees, and the topography of the land surface. The system is demonstrated by modelling a suburban area 4 km from the Fukushima Daiichi Nuclear Power Plant that has yet to be decontaminated. Air dose rates calculated in PHITS were correlated with measurements taken across the site in a car-borne survey.

Modelling the effect of mechanical remediation on dose rates above radiocesium contaminated land

Malins, A.; Kurikami, Hiroshi; Kitamura, Akihiro; Machida, Masahiko

Remediation Measures for Radioactively Contaminated Areas, p.259 - 272, 2019/00

https://doi.org/10.1007/978-3-319-73398-2_12

Development of an air dose rate evaluation system (3D-ADRES) for complex real environments in Fukushima Prefecture; Using remote sensing data and evaluating the influence of different features (topography, soil, buildings, trees, etc.)

Kim, M.; Malins, A.; Sakuma, Kazuyuki; Kitamura, Akihiro; Machida, Masahiko; Hasegawa, Yukihiro*; Yanagi, Hideaki*

RIST News, (64), p.3 - 16, 2018/09

To improve the accuracy of simulations for air dose rates over fallout contaminated areas, the distribution of the radionuclides within the environment should be modelled realistically, e.g. considering differences in radioactivity levels between agricultural land, urban surfaces, and forest compartments. Moreover simulations should model the shielding of rays by buildings, trees and land topography. Here we outline a system for generating three dimensional models of urban and rural areas in Fukushima Prefecture. The Cs and Cs radioactivity distribution can be set flexibly across the different components of the model. The models incorporate realistic representations of local buildings, based on nine common Japanese designs, individual conifer and broadleaf trees, and the topography of the land surface. Models are generated from Digital Elevation Model (DEM) and Digital Surface Model (DSM) datasets, and refined by users assisted with ortho-photographs of target sites. Completed models are exported from the system in a format suitable for the Particle and Heavy Ion Transport code System (PHITS) for the calculation of air dose rates and other radiological quantities. The system is demonstrated by modelling a suburban area 4 km from the Fukushima Daiichi Nuclear Power Plant that has yet to be decontaminated. Air dose rates calculated in PHITS were correlated with measurements taken across the site in a car-borne survey.

Evaluation of sediment and Cs redistribution in the Oginosawa River catchment near the Fukushima Dai-ichi Nuclear Power Plant using integrated watershed modeling

Sakuma, Kazuyuki; Malins, A.; Funaki, Hironori; Kurikami, Hiroshi; Niizato, Tadafumi; Nakanishi, Takahiro; Mori, Koji*; Tada, Kazuhiro*; Kobayashi, Takamaru*; Kitamura, Akihiro; et al.

Journal of Environmental Radioactivity, 182, p.44 - 51, 2018/02

https://doi.org/10.1016/j.jenvrad.2017.11.021

The Oginosawa River catchment lies 15 km south-west of the Fukushima Dai-ichi nuclear plant. The General-purpose Terrestrial Fluid-flow Simulator (GETFLOWS) code was used to study sediment and Cs redistribution within the catchment. Cesium-137 input to watercourses came predominantly from land adjacent to river channels and forest gullies. Forested areas far from the channels only made a minor contribution to Cs input to watercourses, total erosion of between 0.001-0.1 mm from May 2011 to December 2015. The 2.3-6.9% y decrease in the amount of Cs in forest topsoil over the study period can be explained by radioactive decay (approximately 2.3% y), along with a migration downwards into subsoil and a small amount of export. The amount of Cs available for release from land adjacent to rivers is expected to be lower in future than compared to this study period, as the simulations indicate a high depletion of inventory from these areas.