Komatsu, Kazuki*; Iwasaki, Tsugumi*; Murata, Kosuke*; Yamashiro, Hideaki*; Goh, V. S. T.*; Nakayama, Ryo*; Fujishima, Yohei*; Ono, Takumi*; Kino, Yasushi*; Shimizu, Yoshinaka*; et al.
Reproduction in Domestic Animals, 56(3), p.484 - 497, 2021/03
We have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long and continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of raccoons from the ex-evacuation zone of the FDNPP accident. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons.
Kozaki, Tamotsu*; Sawaguchi, Takuma; Fujishima, Atsushi; Sato, Seichi*
Physics and Chemistry of the Earth, 35(6-8), p.254 - 258, 2010/00
Compacted Na-bentonite, of which the major mineral is montmorillonite, is a candidate buffer material for the geological disposal of high-level radioactive waste. A potential alteration of the bentonite in a repository is the partial replacement of the exchangeable cations of Na with Ca. The Ca cations could be released from cementitious materials and diffuse into the buffer material in the repository. In this study, to evaluate the alteration that could reduce the performance of the bentonite buffer, the apparent diffusion coefficients of HTO and Ca ions were determined from non-steady, one-dimensional diffusion experiments using Na- and Ca-montmorillonite mixtures with different ionic equivalent fractions of Ca ions. The apparent diffusion coefficient of HTO at a dry density of 1.0 Mg m slightly increased with an increase in the ionic equivalent fraction of Ca ions. However, the apparent diffusion coefficient of Ca and the activation energy for diffusion at the same dry density were independent of the ionic equivalent fraction of Ca ions. These findings suggest that unlike HTO, which can be postulated to diffuse mainly in pore water, Ca ion diffusion could occur predominantly in interlayer spaces.
Abe, Hironobu; Takahashi, Kazuharu*; Fujishima, Atsushi
JAEA-Data/Code 2009-007, 35 Pages, 2009/07
We are carring out a geological survey to understand important geological structure as geological heterogeneity and migration pathway of material in the bedrock of around the URL area. This report summarizes method and the result of gas measurements, carried out in the Hokushin area and the Suwanosawa area, a period of the FY 2002 to FY 2006. We have investigated gas concentrations of CH and CO (methane and carbon dioxide) along the Omagari fault, and discussed correlations between the gas concentrations and the Omagari fault. The high amount of CO gas concentration were observed around the Omagari Fault.
Umeda, Koji; Oi, Takao; Osawa, Hideaki; Oyama, Takuya; Oda, Chie; Kamei, Gento; Kuji, Masayoshi*; Kurosawa, Hideki; Kobayashi, Yasushi; Sasaki, Yasuo; et al.
JAEA-Review 2007-050, 82 Pages, 2007/12
This report shows the annual report which shows the summarized results and topic outline of each project on geological disposal technology in the fiscal year of 2006.
Nakayama, Masashi; Iriya, Keishiro*; Fujishima, Atsushi; Mihara, Morihiro; Hatanaka, Koichiro; Kurihara, Yuji*; Yui, Mikazu
Materials Research Society Symposium Proceedings, Vol.932, p.159 - 166, 2006/00
Cementitious material is one of candidates of engineered barriers in TRU and HLW repositories. However, since ordinary Portland cement may rises pH of pore water due to its high alkalinity, bentnite and rock which contact with cementitious barriers as a mulch barrier system may deteriorate for a long term by its high pH. Low alkalinity cement with high pozzolanic material content are developed in order to reduce such hyper alkaline deterioration. This paper shows that pH of pore water of this cement is about 11, and that it can be applied for actual structures as self compacting concrete and shotcrete.
; Fujishima, Atsushi
JNC TN1400 2002-014, 15 Pages, 2002/09
no abstracts in English
Suzuki, Satoru; Fujishima, Atsushi; Ueno, Kenichi; Ichikawa, Yasuaki*; Kawamura, Katsuyuki*; Fujii, Naoki*; Shibata, Masahiro; Sato, Haruo; Kitayama, Kazumi*
Nendo Kagaku, 41(2), p.43 - 57, 2001/12
Suzuki, Satoru; Fujishima, Atsushi; Ueno, Kenichi; Ichikawa, Yasuaki*; Kawamura, Katsuyuki*; Fujii, Naoki*; Shibata, Masahiro; Sato, Haruo
JNC TY8400 2001-003, 66 Pages, 2001/05
no abstracts in English
Kato, Tomoko; Fujishima, Atsushi; Ueno, Kenichi; ; Notoya, Shin; Sonobe, Hitoshi
JNC TN8450 2001-003, 203 Pages, 2001/01
We have compiled and refined the information materials to explain ENTRY (Engineering Scale Test and Research Facility) and QUALITY (Quantitative Assessment Radionuclide Migration Experimental Facility). These include information materials to show activities for research and development of radioactive waste disposal in Tokai Works such as panels of experimental equipments. This work was carried out by a working group in Waste Isolation Research Division, Waste Management and Fuel Cycle Research Center; Tokai Works in 19982000. We have developed database for above information materials including typical experimental equipments of ENTRY and QUALITY. In the future, it can be easily refind in case of reconstruction of the experimental equipments. This report presents the database including the experimental equipments and several pamphlet.
Fujishima, Atsushi; Suzuki, Satoru; Ueno, Kenichi; ;
Spring-8 User Experiment Report No.5 (2000A), 0 Pages, 2001/00
Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Ono, Takumi*; Tamaki, Hiroaki*; Kino, Yasushi*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; et al.
no journal, ,
Releases of the radioactive materials from the Fukushima Daiichi Nuclear Power Plant accident result in an ionization exposure to people and animals, the precise dosimetry is required. To estimate the external dose due to the accident, we utilize electron spin resonance (ESR) spectroscopy which is a powerful tool for the dosimetry of external dose. The detection limit of this technique was 146 mGy, so that we have to improve the detection limit for the precise dosimetry. In this work, we developed a novel enamel-dentine separation technique and improved the detection limit down to 43 mGy, and estimated the external dose for Japanese macaque and Procyon lotor collected in Fukushima prefecture.
Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Mitsuyasu, Yusuke*; Ono, Takumi*; Tamaki, Hiroaki*; Kino, Yasushi*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.
no journal, ,
Release of the radioactive materials from Fukushima Daiichi Nuclear Power Plant accident results in a long-term low dose rate ionization exposure to wild animals. The biological effects of the wild animal do not show a clear correlation with the external dose, which is estimated from the external dose rate of the captured point of the animal, a precise external dose estimation using ESR and tooth enamel is required instead of using the external dose rate. In this work, we attempted to estimate the external dose of wild Japanese macaque and Procyon lotor captured in the high dose rate area.
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.
Fujishima, Yohei*; Suzuki, Masatoshi*; Goh, V. S. T.*; Ariyoshi, Kentaro*; Kasai, Kosuke*; Nakata, Akifumi*; Kino, Yasushi*; Oka, Toshitaka; Shinoda, Hisashi*; Shimizu, Yoshinaka*; et al.
no journal, ,
After the Fukushima Daiichi Nuclear Power Plant accident, the surrounding environment was contaminated with radionuclides. Although the ambient dose rates are decreasing, prolonged effects of chronic low-dose exposure on animals are expected to be seen in the coming years. It is necessary to assess the effects of radioactivity on the wild animals in this area to better understand about the risk of low dose radiation. The chromosome translocation frequency of Japanese macaques were significantly higher in Fukushima groups comparing from control groups in Miyagi. Furthermore, chromosome translocation frequencies tended to correlate between external doses or internal dose-rates. However, chromosome translocation frequency was decreasing year by year, which may reflect restoration of environments such as decreasing of ambient dose-rates and decontamination efforts.
Oka, Toshitaka; Takahashi, Atsushi*; Mitsuyasu, Yusuke*; Koarai, Kazuma; Kino, Yasushi*; Okutsu, Kenichi*; Yamashita, Takuma*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.
no journal, ,
Electron spin resonance (ESR) dosimetry technique is a powerful tool that has been used in the study of external exposure dose assessment of human by measuring CO radicals of teeth. In this work, we applied this technique for wild monkey and wild racoon captured in Fukushima prefecture, and estimated the external exposure dose.