Fukushima Daiichi Nuclear Power Plant Accident; Understanding Formation Mechanism of Radioactive Particles through Sr and Pu Quantities

Igarashi, Junya*; Ninomiya, Kazuhiko*; Zheng, J.*; Zhang, Z. J.*; Fukuda, Miho*; Aono, Tatsuo*; Minowa, Haruka*; Yoshikawa, Hideki*; Sueki, Keisuke*; Satou, Yukihiko; et al.

Environmental Science & Technology, 58(33), p.14823 - 14830, 2024/08

https://doi.org/10.1021/acs.est.4c03428

Depth profile and inventory of Cl in soil near the Fukushima Dai-ichi Nuclear Power Plant

Ota, Yuki*; Sueki, Keisuke*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Matsunaka, Tetsuya*; Matsumura, Masumi*; Tosaki, Yuki*; Honda, Maki*; Hosoya, Seiji*; Takano, Kenta*; et al.

JAEA-Conf 2018-002, p.99 - 102, 2019/02

https://doi.org/10.11484/jaea-conf-2018-002

no abstracts in English

Photostimulated luminescence applicable to pre-screening of potassium-rich phases in chondritic breccias

Yokoyama, Tatsunori; Misawa, Keiji*; Okano, Osamu*; Minowa, Haruka*; Fukuoka, Takaaki*

Journal of Radioanalytical and Nuclear Chemistry, 310(1), p.81 - 89, 2016/10

https://doi.org/10.1007/s10967-016-4846-x

The identification of alkali-rich components in extraterrestrial materials along with their separation from other constituents is indispensable for subsequent cosmochemical and isotopic studies. This paper presents a simple pre-screening method for such materials by autoradiography using imaging plates (IPs), which is applicable to identification of mm-sized samples containing ca. 30 g of potassium in the Yamayo-74442 chondrite. The detection limit of IPs was 1 mBq of K under 49 days exposure. The method provides an opportunity to screen meteorite materials non-destructively and to inexpensively check potassium-rich areas and suitable for the K-Ca and K-Ar (Ar-Ar) age determinations.

Characteristic of radioactive particles discovered from the near of Fukushima Dai-ichi Nuclear Power Plant

Satou, Yukihiko*; Sueki, Keisuke*; Sasa, Kimikazu*; Minowa, Haruka*; Yoshikawa, Hideki; Fujiwara, Kenso; Nakama, Shigeo; Adachi, Koji*; Igarashi, Yasuhito*

no journal, , 

Radioactive particle including high density cesium were released caused by the Fukushima Daiichi nuclear disaster. In this study, we analyzed distribution of radioactive particle and its characteristic about obtained soils and dusts. As a result, radioactive particles were confirmed from soil sample. In particular, 100 micro meter in diameters particles were found at the point of north-northwest direction approximately 7km from the nuclear power plant. Found particles resembled an elementary composition and surface state of the particle found in the 20km northwest from nuclear power plant and Tsukuba.

Research for the spatial diffusion of radionuclide from Cs/Cs ratio in indoor dust from near the Fukushima Daiichi Nuclear Power Plant

Minowa, Haruka*; Yoshikawa, Hideki; Nakama, Shigeo; Satou, Yukihiko; Sueki, Keisuke*

no journal, , 

In this study, we aimed to estimate the diffusion distribution of radioactive Cs from each reactor source using the environmental samples. First, the influence of the sum-peak effect on the counting efficiency of Cs in the Ge detector was investigated for the accurately radioactive measurement, and applied it to the actual sample. To measure the variation of the counting efficiency depends on the distance between the Ge detector and a sample, a disk-shaped standard sample (25 mm of filter paper) and a particle standard sample (200 m in size) were used. When the sample was placed close to the detector (distance 0.1 mm), the counting efficiency [cps/Bq] of Cs was about 20% lower than that of Cs in both the disk-shaped and the particle standard sample. It seemed to be caused by the sum-peak effect. "Smear paper" samples with indoor dust collected from about 40 points within 10 km from Fukushima Daiichi Nuclear Power Plant in 2014-2019 were measured, and Cs and Cs were quantified using the counting efficiency with the disk-shaped standard sample. From the Cs/Cs ratio at the time of the accident, the mixing ratio of materials derived from Reactors 1, 2 and 3 was estimated, and the spatial diffusion distribution of radioactive materials for each reactor was indicated.

Estimation for distribution of Cs-bearing radioactive particles emitted in the Fukushima Dai-ichi Power Station accident

Satou, Yukihiko; Sueki, Keisuke*; Matsuo, Kazuki*; Minowa, Haruka*; Yoshikawa, Hideki

no journal, , 

no abstracts in English

Radioactive particles discovered in the vicinity of Fukushima Nuclear Plant

Satou, Yukihiko*; Sueki, Keisuke*; Sasa, Kimikazu*; Minowa, Haruka*; Yoshikawa, Hideki; Fujiwara, Kenso; Nakama, Shigeo

no journal, , 

We separated radioactive particles from soil and dust sample obtained around Fukushima Dai-ichi Nuclear Power Plant. Separated all particles can categorize unit-1 and unit-2 origin. And Sb was detected from unit-1 origin samples. Moreover, radioactive particle was made up 80 weight percent silica.

Research for the distribution of radiocesium-bearing particles in dust from near the Fukushima Daiichi Nuclear Power Plant

Minowa, Haruka*; Yoshikawa, Hideki; Nakama, Shigeo; Satou, Yukihiko; Sueki, Keisuke*

no journal, , 

no abstracts in English

Shape of Cs-particles in soils close to the Fukushima Daiichi Nuclear Power Plant

Satou, Yukihiko*; Sueki, Keisuke*; Minowa, Haruka*; Nakama, Shigeo; Yoshikawa, Hideki

no journal, , 

We obtained the soil sample close to the Fukushima Daiichi Nuclear Power Plant. The particle including highly cesium was separated from the soil sample. Estimated ratio of Cs to Cs is 0.90. This ratio accorded with 1st unit of Fukushima Daiichi Nuclear Power Plant.