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Cs supply from rivers to coastal waters off Fukushima on the Cs behavior in seabed sedimentIkenoue, Tsubasa; Nakanishi, Takahiro; Shimadera, Hikari*; Kawamura, Hideyuki; Kondo, Akira*
E3S Web of Conferences (Internet), 530, p.02005_1 - 02005_10, 2024/05
The accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) caused a radioactive contamination in seabed sediment. The Cs supply from rivers could be an important process for the long-term behavior of Cs in seabed sediment. In this study, a ten-year simulation of the Cs behavior in seabed sediment was conducted using an oceanic dispersion model combined with a prediction model of Cs behavior in land and river. In the waters north of FDNPP, the simulation results suggested that the Cs supply from rivers had a great impact on the concentrations in coastal sediment due to the initial low concentrations in seabed sediment and the large supply of Cs from rivers. In the waters near FDNPP and south of FDNPP, the simulation results suggested that the impact of the Cs supply on the temporal variation of Cs concentration in coastal sediment was relatively small due to the large initial adsorption from seawater. Overall, these results indicated that Cs supply from rivers had an impact on the spatiotemporal distribution of Cs concentrations in seabed sediment on a decadal time scale and the impact was especially great in the waters north of FDNPP.
Konoplev, A.*; Golosov, V.*; Laptev, G.*; Namba, Kenji*; Onda, Yuichi*; Takase, Tsugiko*; Wakiyama, Yoshifumi*; Yoshimura, Kazuya
Journal of Environmental Radioactivity, 151(Part 3), p.568 - 578, 2016/01
Times Cited Count：82 Percentile：91.39(Environmental Sciences)Hayashi, Hiroko*; Matsuoka, Shungo*; Takahashi, Tomoyuki*; Amano, Hikaru
JAERI-Conf 2003-010, p.122 - 130, 2003/09
Two dynamic compartment models were constructed as basic river models for MOGRA (Migration Of GRound Additions), an environmental-load effect predicting code. One is 1 component river model, in which radionuclides in particulate form and dissolved form are considered to be in equilibrium in the river water. Another one is 2 component river model, in which particulate form and dissolved form are considered to be different component and are separately compartmentalized. In each model the river sediment is set in a compartment, and the sedimentation of particulate form and resuspension of radionuclides in the river sediment are taken into account.To verify the analysis function of the constructed models, calculation conditions were set using data of Cs-137 concentration in the river water derived from Kuji river, Japan, and analysis was carried out. Comparing two models, almost no difference is seen when sedimentation velocity is low, while there is apparent difference when sedimentation velocity is high.
Sanada, Yukihisa*; Matsunaga, Takeshi; Yanase, Nobuyuki; Nagao, Seiya; Amano, Hikaru; Takada, Hideshige*; Tkachenko, Y.*
Applied Radiation and Isotopes, 56(5), p.751 - 760, 2002/04
Times Cited Count：14 Percentile：65.07(Chemistry, Inorganic & Nuclear)Areas contaminated with radionuclides from the Chernobyl nuclear accident have been identified in Pripyat River near the Chernobyl Nuclear Power Plant. The bottom sediments contained Cs (10
- 10
Bq/m
) within 0-30 cm depth, which is comparable to the ground soil of in the vicinity of the nuclear power plant (the Exclusion Zone). The sediments also accumulated 
Sr (10 Bq/m ), 
Pu (10
Bq/m ), 
Am (10 Bq/m ) derived from the accident.The comparison of these inventories with those of the released radionuclides at the accident and the experimental analysis using the selective sequential extraction of the radionuclides in the sediments suggest that the potential mobility of Cs and Pu is low compared with Sr in the bottom sediment, while the potential dissolution of Sr from the river bottom sediment should be taken into account with respect to the long-term radiological influence on the aquatic environment.
Iijima, Kazuki; Funaki, Hironori; Oyama, Takuya; Niizato, Tadafumi; Sato, Haruo*; Yui, Mikazu
no journal, ,
Goal of the project is to develop mechanistic models to predict transport behavior of radioelements strongly adsorbed on soil particles from forests to sea through river systems, evaluate evolution of dose, and propose methods to constrain the transport. This study overviewed the behavior of radioactive caesium through one of the river systems in the coastal area of Fukushima. Concequently, caesium is considered to be strongly adsorbed on the soil particles in the transport through the river water system since more than 90% of caesium has still remained within 5 cm from the surface of topsoil in the forest, and the concentration of caesium in the lake water was extremely low. The difference of concentrations of caesium in the sediments in the river water system can be explained by the effect of particle size on the adsorption site density of caesium.
Ikenoue, Tsubasa
no journal, ,
We report the results of a recent simulation study by JAEA on the behavior of radiocesium (Cs) released by the Fukushima Daiichi Nuclear Power Plant accident (1F accident) near the coastal seafloor. The Cs supply from rivers could be an important process for the long-term behavior of Cs in seabed sediment. In this study, we conducted a simulation to predict the behavior of Cs in seabed sediment by combining an ocean dispersion model with a river model. Based on the simulation results, we explain the impact of Cs supply from rivers on the long-term behavior of Cs in seabed sediment.
Onda, Yuichi*; Yoshimura, Kazuya; Taniguchi, Keisuke*; Kubo, Takaaki*; Smith, H.*; Blake, W.*; Kuramoto, Takayuki*; Sato, Takayuki*
no journal, ,
