Radiocesium distribution in the sediments of the Odaka River estuary, Fukushima, Japan

Hagiwara, Hiroki; Nakanishi, Takahiro; Konishi, Hiromi*; Tsuruta, Tadahiko; Misono, Toshiharu; Fujiwara, Kenso; Kitamura, Akihiro

Journal of Environmental Radioactivity, 220-221, p.106294_1 - 106294_9, 2020/09

https://doi.org/10.1016/j.jenvrad.2020.106294

Radiocaesium distribution in a Fukushima river estuary

Hagiwara, Hiroki; Konishi, Hiromi*; Nakanishi, Takahiro; Harada, Hisaya; Tsuruta, Tadahiko

no journal, , 

Mineralogical study of transporting radiocesium sorbed media

Hagiwara, Hiroki; Konishi, Hiromi*

no journal, , 

Identification of radiocesium sorbed minerals in sediments is important in view of adsorbed or desorbed mechanism between minerals and radiocesium in river water. Recently, the authors reported that not only micas but also mafic minerals could contribute toward the radiocesium migration in Fukushima river basin. In this study, we investigated crystal structure of hornblende in riverbed of mafic minerals using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) within Tomioka river. The results showed a part of surface on hornblende is altered to clay minerals. We also confirmed hornblende had cleavages and fractures which filling altered minerals inner part. This implies that these altered minerals could be contribute radiocesium adsorbing.

Relationship between mineralogical composition and radiocesium on bottom sediment at estuary of Odaka River

Hagiwara, Hiroki; Iijima, Kazuki; Onoe, Hironori; Oyama, Takuya; Nakanishi, Takahiro; Konishi, Hiromi*; Akai, Junji*

no journal, , 

Estuary of alluvial is specific area which has shelved land form gradient and current velocity is degraded by mixing freshwater and seawater. The radiocaesium from the Fukushima nuclear accident fallout is strongly sorbed on fine grain size particles. It is necessary for fine grain size particles to evaluate behavior at estuary. we measured salinity concentration and sampled bottom sediment. Bottom sediments were analyzed by XRD and TEM. The results showed salinity distribution and the sediments include black color sediments. It is confirmed halloysite, diatome, and bacteria by TEM. The area has higher radiocaesium concentration than upstream.

Study on tritium production using high-temperature gas-cooled reactor for fusion reactors; Structure of the irradiation test module and experimental method

Kitagawa, Kanta*; Matsuura, Hideaki*; Kawai, Hiromi*; Katayama, Kazunari*; Otsuka, Teppei*; Ishitsuka, Etsuo; Nakagawa, Shigeaki; Goto, Minoru*; Tobita, Kenji*; Konishi, Satoshi*; et al.

no journal, , 

Tritium production using a high temperature gas cooled reactor has been studied to get for the start-up of an initial DEMO fusion reactor and for technical testing of related tritium circulation systems. The characteristics of hydrogen absorption in the case of change from room temperature to high temperature for zirconium particle with nickel coating was obtained and investigated the analytical simulation model. And the configuration (for example, the numbers of zirconium particle with nickel coating and the amount of LiAlO) of test specimen for irradiation test and the test method were discussed.