Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Misono, Toshiharu; Tsuruta, Tadahiko; Nakanishi, Takahiro; Sanada, Yukihisa; Shiribiki, Takehiko; Miyamoto, Kenji*; Urabe, Yoshimi*
JAEA-Research 2020-008, 166 Pages, 2020/10
JAEA-Research-2020-008.pdf:13.11MBJAEA-Research-2020-008(errata).pdf:0.92MB
After the accident at TEPCO Fukushima Daiichi Nuclear Power Station (1F), marine monitoring survey on radioactive substances have been conducted with financially supported by the Nuclear Regulatory Agency from FY2019. Results obtain in the project in FY2019 are presented in this report. Based on scientific grounds, the concept necessary for "progress of sea area monitoring" was arranged for the future medium- to long-term investigation of radiocesium concentrations. As basic information of survey frequency revise, a seabed topography and sediment distribution survey was conducted, and an attempt was made to understand the relationship between the seabed topography and the grain size distribution of bottom sediment. A columnar core sample was collected in the coastal area and analyzed for radioactive cesium concentration. In order to understand the dynamics of radioactive cesium contained in suspended matter flowing in from a river, suspended solids was collected using a sediment trap and the concentration of radioactive cesium was measured. We re-analyzed the towed monitoring data that had been implemented since 2013, and tried to improve the accuracy of the radioactive cesium distribution estimation map in the coastal area.
Cs in seabed sediments around the river mouth near Fukushima Daiichi Nuclear Power PlantTsuruta, Tadahiko; Harada, Hisaya*; Misono, Toshiharu; Matsuoka, Toshiyuki; Hodotsuka, Yasuyuki*
Journal of Oceanography, 73(5), p.547 - 558, 2017/10
Times Cited Count：11 Percentile：47.82(Oceanography)The seafloor topography was divided into flat and terrace seafloors based on their topographical features and seabed sediments were distributed in an area that was half a degree of the entire investigation area. The Cs inventory was several tens of kBq/m
and the grain sizes (the D50 values) were nearly constant (fine sand) on the flat seafloor. On the terrace seafloor, the Cs inventory was larger than that on the flat seafloor, and the grain size varied from silt to coarse sand. The grain size distributions appear to be influenced by the mean shear stress at the seafloor bottom, and a significant factor in the mean shear stress is thought to be the seafloor topography. Distributions of remarkably large Cs inventories, more than several thousands of kBq/m, are thought to be confined to a small area. Vertical changes in the Cs inventories suggested that the Cs inventories have significantly decreased in large areas of the shallow sea.
; ; ; ; *; *
J.Oceanogr.Sci.Jpn., 40, p.98 - 104, 1984/00
no abstracts in English
