Mathematical Modeling of Radioactive Contaminants in the Fukushima Environment

Kitamura, Akihiro; Kurikami, Hiroshi; Yamaguchi, Masatoshi; Oda, Yoshihiro; Saito, Takamichi; Kato, T.; Niizato, Tadafumi; Iijima, Kazuki; Sato, Haruo; Yui, Mikazu; Machida, Masahiko; Yamada, S.; Itakura, Mitsuhiro; Okumura, Masahiko; Onishi, Yasuo

doi:10.13182/nse13-89

Cited by 10 publications

(7 citation statements)

References 2 publications

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“…In particular, they focused on land-use as they argued it may have the greatest potential impact on soil erosion. This model is also described in and discussed in Kitamura et al (2015). These authors reported that 8.4 TBq of 137 Cs will be exported to the Pacific Ocean in the immediate years following the FDNPP accident .…”

Section: Modelling Radiocesium Catchment Scale Transfersmentioning

confidence: 97%

“…Kitamura et al (2014) reported the results from the application of the Time-dependent One-dimensional Degradation and Migration (TODAM) model in the Ukedo Catchment. This model is also outlined in Kurikami et al (2014) and discussed in Kitamura et al (2015). The TODAM model incorporates the deposition and resuspension of sediment along with the potential desorption/ adsorption of radiocesium within sub-models.…”

Section: Modelling Radiocesium Catchment Scale Transfersmentioning

confidence: 99%

“…Yamada et al (2015) also modelled radiocesium dynamics for the Ogaki Dam with the Nay2D model (Shimizu, 2003) to examine the influence of countermeasures such as controlling the reservoir volume on 137 Cs export. This paper was also discussed in Kitamura et al (2015). The authors compared a September 2013 flood event to the long-term average flood event and calculated 137 Cs deposition and export.…”

Section: Modelling Radiocesium Catchment Scale Transfersmentioning

confidence: 99%

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Radiocesium transfer from hillslopes to the Pacific Ocean after the Fukushima Nuclear Power Plant accident: A review

Evrard

Laceby

Lepage

et al. 2015

Journal of Environmental Radioactivity

156

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The devastating tsunami triggered by the Great East Japan Earthquake on March 11, 2011 inundated the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) resulting in a loss of cooling and a series of explosions releasing the largest quantity of radioactive material into the atmosphere since the Chernobyl nuclear accident. Although 80% of the radionuclides from this accidental release were transported over the Pacific Ocean, 20% were deposited over Japanese coastal catchments that are subject to frequent typhoons. Among the radioisotopes released during the FDNPP accident, radiocesium ((134)Cs and (137)Cs) is considered the most serious current and future health risk for the local population. The goal of this review is to synthesize research relevant to the transfer of FDNPP derived radiocesium from hillslopes to the Pacific Ocean. After radiocesium fallout deposition on vegetation and soils, the contamination may remain stored in forest canopies, in vegetative litter on the ground, or in the soil. Once radiocesium contacts soil, it is quickly and almost irreversibly bound to fine soil particles. The kinetic energy of raindrops instigates the displacement of soil particles, and their bound radiocesium, which may be mobilized and transported with overland flow. Soil erosion is one of the main processes transferring particle-bound radiocesium from hillslopes through rivers and streams, and ultimately to the Pacific Ocean. Accordingly this review will summarize results regarding the fundamental processes and dynamics that govern radiocesium transfer from hillslopes to the Pacific Ocean published in the literature within the first four years after the FDNPP accident. The majority of radiocesium is reported to be transported in the particulate fraction, attached to fine particles. The contribution of the dissolved fraction to radiocesium migration is only relevant in base flows and is hypothesized to decline over time. Owing to the hydro-meteorological context of the Fukushima region, the most significant transfer of particulate-bound radiocesium occurs during major rainfall and runoff events (e.g. typhoons and spring snowmelt). There may be radiocesium storage within catchments in forests, floodplains and even within hillslopes that may be remobilized and contaminate downstream areas, even areas that did not receive fallout or may have been decontaminated. Overall this review demonstrates that characterizing the different mechanisms and factors driving radiocesium transfer is important. In particular, the review determined that quantifying the remaining catchment radiocesium inventory allows for a relative comparison of radiocesium transfer research from hillslope to catchment scales. Further, owing to the variety of mechanisms and factors, a transdisciplinary approach is required involving geomorphologists, hydrologists, soil and forestry scientists, and mathematical modellers to comprehensively quantify radiocesium transfers and dynamics. Characterizing radiocesium transfers from hillslopes to the Pacific Ocean is necess...

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Section: Modelling Radiocesium Catchment Scale Transfersmentioning

confidence: 97%

Section: Modelling Radiocesium Catchment Scale Transfersmentioning

confidence: 99%

Section: Modelling Radiocesium Catchment Scale Transfersmentioning

confidence: 99%

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Radiocesium transfer from hillslopes to the Pacific Ocean after the Fukushima Nuclear Power Plant accident: A review

Evrard

Laceby

Lepage

et al. 2015

Journal of Environmental Radioactivity

156

View full text Add to dashboard Cite

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“…Detailed information can be found on the Japan Dam Foundation website (in Japanese), in a paper by Funaki et al (2014), and a previous report by Onishi et al (2014). This dam is a main focus of the JAEA Transport of Radioactive Contaminant in the Environment of Fukushima (F-TRACE) research project (Iijima et al 2013;Kitamura et al 2015). Under the F-TRACE project, JAEA monitors and samples water and sediment deposits in the reservoir and in the river into the reservoir to evaluate cesium distributions.…”

Section: Flow Analysis Of the Ogi Dam Reservoir Modelmentioning

confidence: 99%

Environmental, Transient, Three-Dimensional, Hydrothermal, Mass Transport Code - FLESCOT

Onishi¹,

Bao²,

Glass³

et al. 2015

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“…The large-scale environmental monitoring continuously performed in the national projects has provided a large amount of important information, and the analysis of the obtained data helped characterizing the contamination conditions in Fukushima and their temporal changes [4][5][6]. Meanwhile, migration of radiocesium has been studied in several projects to clarify the underlying mechanism of change in radiation levels [2,7,8]. The results of these projects have made it possible to image on how radiocesium has migrated in the environment around the Fukushima site.…”

Section: Introductionmentioning

confidence: 99%

Temporal Change in Radiological Environments on Land after the Fukushima Daiichi Nuclear Power Plant Accident

et al. 2019

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Massive environmental monitoring has been conducted continuously since the Fukushima Daiichi Nuclear Power accident in March of 2011 by different monitoring methods that have different features together with migration studies of radiocesium in diverse environments. These results have clarified the characteristics of radiological environments and their temporal change around the Fukushima site. At three months after the accident, multiple radionuclides including radiostrontium and plutonium were detected in many locations; and it was confirmed that radiocesium was most important from the viewpoint of long-term exposure. Radiation levels around the Fukushima site have decreased greatly over time. The decreasing trend was found to change variously according to local conditions. The air dose rates in environments related to human living have decreased faster than expected from radioactive decay by a factor of 2-3 on average; those in pure forest have decreased more closely to physical decay. The main causes of air dose rate reduction were judged to be radioactive decay, movement of radiocesium in vertical and horizontal directions, and decontamination. Land-use categories and human activities have significantly affected the reduction tendency. Difference in the air dose rate reduction trends can be explained qualitatively according to the knowledge obtained in radiocesium migration studies; whereas, the quantitative explanation for individual sites is an important future challenge. The ecological half-lives of air dose rates have been evaluated by several researchers, and a short-term half-life within 1 year was commonly observed in the studies. An empirical model for predicting air dose rate distribution was developed based on statistical analysis of an extensive car-borne survey dataset, which enabled the prediction with confidence intervals. Different types of contamination maps were integrated to better quantify the spatial data. The obtained data were used for extended studies such as for identifying the main reactor that caused the contamination of arbitrary regions and developing standard procedures for environmental measurement and sampling. Annual external exposure doses for residents who intended to return to their homes were estimated as within a few millisieverts. Different forms of environmental data and knowledge have been provided for wide spectrum of people. Diverse aspects of lessons learned from the Fukushima accident, including practical ones, must be passed on to future generations.

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Mathematical Modeling of Radioactive Contaminants in the Fukushima Environment

Cited by 10 publications

References 2 publications

Radiocesium transfer from hillslopes to the Pacific Ocean after the Fukushima Nuclear Power Plant accident: A review

Radiocesium transfer from hillslopes to the Pacific Ocean after the Fukushima Nuclear Power Plant accident: A review

Environmental, Transient, Three-Dimensional, Hydrothermal, Mass Transport Code - FLESCOT

Temporal Change in Radiological Environments on Land after the Fukushima Daiichi Nuclear Power Plant Accident

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