Experiences on deep borehole drilling in Neogene sedimentary formations during surface-based investigation phase

Matsui, Hiroya; Sasaki, Manabu*

JAEA-Technology 2006-052, 101 Pages, 2006/11

JAEA-Technology-2006-052.pdf:9.64MB

Japan Atomic Energy Agency (JAEA) has been conducting the project with construction of the Underground Research Laboratory (URL) called "Horonobe URL Project" since FY2000/FY2001 in Horonobe-cho, Hokkaido in Japan. The project is divided into three major phase, such as surface-based investigation phase, construction phase and operation phase. Total duration of the project is about 20 years. In the surface-based investigation phase, the eleven deep borehole investigations, which were drilled until 1000m depth, have carried out to understand a geological environment in the selected URL area formed Neocence sedimentary formations in Horonobe-cho. This report describe summarized important experiences to perform the deep borehole investigations with max. 1000m depth. This information could be great helpful for future site investigations.

Working program for deep borehole investigations -HDB-6,7,8 boreholes-

Hama, Katsuhiro; Takahashi, Kazuharu; Ishii, Eiichi; Takeuchi, Ryuji; Sasaki, Manabu; Kunimaru, Takanori; Matsui, Hiroya

JNC-TN5400 2003-002, 61 Pages, 2003/08

JNC-TN5400-2003-002.pdf:5.42MB
JNC-TN5400-2003-002(errata).pdf:0.08MB

The working program for deep borehole investigations (HDB-6,7,8 boreholes).

Evidence for a narrow = +1 Baryon resonance in photoproduction from the neutron

Nakano, Takashi*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Date, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; Fujiwara, Mamoru; et al.

Physical Review Letters, 91(1), p.012002_1 - 012002_4, 2003/07

https://doi.org/10.1103/PhysRevLett.91.012002

no abstracts in English

Incorporation record of radionuclides in teeth and otoliths

Koarai, Kazuma; Matsueda, Makoto; Fujiwara, Kenso; Ono, Takumi*; Kino, Yasushi*; Oka, Toshitaka; Okutsu, Kenichi*; Takahashi, Atsushi*; Suzuki, Toshihiko*; Shimizu, Yoshinaka*; et al.

no journal, , 

We have investigated incorporation of Sr and Cs in teeth of cattle and otoliths of fish. Specific activity of Sr in the dentin tissue was higher than that in the enamel tissue. The result shows change of Sr incorporation in cattle even within a tooth. Concentrations of stable Sr and Cs were 94 ppm and 3 ppb. Distributions of stable Sr and Cs were uniform in the otolith of fish. If distribution of Sr and Cs in the otolith was measured, change of Sr and Cs incorporation into the fish would be found. These findings suggest that distribution patterns of Sr and Cs in the environment could be estimated from distribution of the radionuclides in the tooth and otolith.

External exposure dose of Japanese macaque captured in Fukushima prefecture

Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Mitsuyasu, Yusuke*; Kino, Yasushi*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; Osaka, Ken*; et al.

no journal, , 

Due to the Fukushima Daiichi Nuclear Power Plant accident, the exposure dose estimation for human is examined by the whole body counter or by the Fukushima Health Management Survey, however, the precise estimated dose cannot obtained by such methods. We applied electron spin resonance (ESR) dosimetry for the external dose estimation using tooth enamel of human/animal. As we reported last year, we improved the detection limit of ESR dosimetry down to 43 mGy. We used this improved ESR dosimetry system and attempted to estimate the external dose of wild Japanese macaque capture in Fukushima prefecture, however, the metal component which may obstruct the ESR measurement was observed, so that we cannot estimate the external dose. In this work, we investigated how to remove such metal components, obtain the clear ESR spectrum, and estimate the external dose.

Sample preparation procedure for ESR dosimetry using teeth of wild animal

Oka, Toshitaka; Mitsuyasu, Yusuke*; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Sekine, Tsutomu*; Okutsu, Kenichi*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.

no journal, , 

Releases of the radioactive materials from the Fukushima Daiichi Nuclear Power Plant accident result in a low dose exposure to wild animals. The external dose of wild animals is commonly estimated by the external dose rate of the captured point, but the estimated exposure dose has huge uncertainties because the size of the habitat and/or the movement of the wild animals are not included in the estimation. To estimate the external dose precisely, we utilize electron spin resonance (ESR) dosimetry. In this work, we investigated the sample preparation procedure of wild animals. The ESR spectrum of enamel of racoon captured in Namie-town, Fukushima has a broad ESR signal due to metal components. The linear relationship between the Co intensity and the absorbed dose that we can apply ESR dosimetry for racoon teeth. Using this relationship, the external exposure dose was estimated.