Statistical analysis of simulated oceanic dispersion of dissolved radionuclide hypothetically released from the Fukushima Dai-ichi Nuclear Power Plant using long-term oceanographic reanalysis data

Ikenoue, Tsubasa; Kawamura, Hideyuki; Kamidaira, Yuki

Journal of Nuclear Science and Technology, 60(1), p.61 - 71, 2023/01

https://doi.org/10.1080/00223131.2022.2079569

We conducted numerical simulations on the oceanic dispersion of dissolved radionuclide hypothetically released from the Fukushima Dai-ichi Nuclear Power Plant using long-term oceanographic reanalysis data. We evaluated the characteristics and trends of dissolved radionuclide behavior in the ocean using statistical analysis based on the simulation results. The surface meridional current at the release point in the Fukushima coastal ocean and the Kuroshio Extension significantly affected the north-south transport of the surface radionuclide in the Fukushima coastal ocean and the eastward transport of the offshore surface radionuclide, respectively. Because the surface kinetic energy in the coastal to the offshore area was larger, the range of the dispersed surface radionuclide tended to be larger. In summer (July-September), the increased frequency radionuclide entrainment by the Kuroshio Extension because of the surface southward radionuclide transport in the Fukushima coastal ocean and the large surface kinetic energy caused a large dispersed surface radionuclide. In winter (January-March), the decreased frequency radionuclide entrainment by the Kuroshio Extension because of the surface northward radionuclide transport in the Fukushima coastal ocean and the small surface kinetic energy caused a small dispersed surface radionuclide.

Challenges for enhancing Fukushima environmental resilience, 7; Behavior and abundance of radiocesium in the coastal area off Fukushima

Otosaka, Shigeyoshi; Kobayashi, Takuya; Machida, Masahiko

Nihon Genshiryoku Gakkai-Shi ATOMO, 59(11), p.659 - 663, 2017/11

It is estimated that about 70% of radiocesium released to the environment by the Fukushima Daiichi nuclear accident was carried to the ocean. In addition to monitoring surveys by the government, oceanographic research by many institutions has revealed the distribution and behavior of the accident-derived radiocesium in the ocean. Numerical simulations are efficiently used in such oceanographic investigations, and further improvements are being made based on findings newly obtained after the accident. In this paper, we review the abundance and behavior of radiocesium in the coastal area of Fukushima, deepen the scientific understanding of the current situation of environmental restoration, and explain the issues to be addressed in the future.

None

*

PNC TJ1604 94-001, 24 Pages, 1994/03

PNC-TJ1604-94-001.pdf:2.64MB

no abstracts in English

Utilization of super-computer in nuclear sciences; Application to environmental problems

Ishikawa, Hirohiko

Genshiryoku Kogyo, 38(3), p.43 - 48, 1992/00

http://ci.nii.ac.jp/naid/40001074010

no abstracts in English

The Development of Coastal Diffusion Observation Method with a Model Airplane

;

JAERI-M 9908, 13 Pages, 1982/01

JAERI-M-9908.pdf:0.75MB

no abstracts in English

Oceanic dispersion of Fukushima-derived Cs-137 in the coastal, offshore, and open oceans simulated by multiple oceanic general circulation models

Kawamura, Hideyuki; Furuno, Akiko; Kobayashi, Takuya; In, Teiji*; Nakayama, Tomoharu*; Ishikawa, Yoichi*; Miyazawa, Yasumasa*; Usui, Norihisa*

no journal, , 

This study simulates the oceanic dispersion of Fukushima-derived Cs-137 by an oceanic dispersion model SEA-GEARN-FDM and multiple oceanic general circulation models. The oceanic dispersion simulations relatively well reproduced the measured Cs-137 concentrations in the coastal and offshore oceans during the first few months after the Fukushima disaster, and in the open ocean during the first year post-disaster. It was suggested that Cs-137 dispersed along the coast in the north-south direction during the first few months post-disaster, and were subsequently dispersed offshore by the Kuroshio Current and Kuroshio Extension. The Cs-137 amounts were quantified in the coastal, offshore, and open oceans during the first year post-disaster. It was demonstrated that Cs-137 actively dispersed from the coastal and offshore oceans to the open ocean, and from the surface layer to the deeper layer in the North Pacific.

Analysis of oceanic dispersal of Cs derived from Fukushima Dai-ichi Nuclear Power Plant using the short-term emergency assessment system of marine environmental radioactivity

Ikenoue, Tsubasa; Kawamura, Hideyuki; Kamidaira, Yuki

no journal, , 

In this study, we analyzed the characteristics and trends of oceanic dispersal of Cs by performing the oceanic dispersion simulations using past oceanographic data received on the Short-Term Emergency Assessment system of Marine Environmental Radioactivity (STEAMER) developed at JAEA. Oceanic dispersion simulations in 1461 cases were carried out in the northwestern Pacific Ocean for 60 days from every day between 2015 and 2018. It was assumed that Cs was released into the ocean from the Fukushima Dai-ichi Nuclear Power Plant. In all calculation cases, the maximum concentration in 30 days at each computational grid (maximum concentration distribution) was calculated. Cs in the ocean surface in winter tended to be not dispersed so much. In the ocean surface, the seasonal variation was greater than the annual variation though the maximum concentration distributions have little annual variation. The average of the maximum concentration distribution in all calculation cases was inclined to be high from the coast of Fukushima to the offshore (140E-145E) and near the Kuroshio Extension.