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Yasuoka, Yumi*; Fujita, Hiroki; Tsuji, Tomoya; Tsujiguchi, Takakiyo*; Sasaki, Michiya*; Miyazaki, Tomoyuki*; Hashima, Shun*; Yasuda, Hiroshi*; Shimada, Kazumasa; Hirota, Seiko*
Hoken Butsuri (Internet), 57(3), p.146 - 155, 2022/12
no abstracts in English
Nagao, Fumiya; Niizato, Tadafumi; Sasaki, Yoshito; Ito, Satomi; Watanabe, Takayoshi; Dohi, Terumi; Nakanishi, Takahiro; Sakuma, Kazuyuki; Hagiwara, Hiroki; Funaki, Hironori; et al.
JAEA-Research 2020-007, 249 Pages, 2020/10
JAEA-Research-2020-007.pdf:15.83MB
The accident of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. occurred due to the Great East Japan Earthquake, Sanriku offshore earthquake, of 9.0 magnitude and the accompanying tsunami. As a result, large amount of radioactive materials was released into the environment. Under these circumstances, Japan Atomic Energy Agency (JAEA) has been conducting "Long-term Assessment of Transport of Radioactive Contaminants in the Environment of Fukushima" concerning radioactive materials released in environment, especially migration behavior of radioactive cesium since November 2012. This report is a summary of the research results that have been obtained in environmental dynamics research conducted by JAEA in Fukushima Prefecture.
Nagao, Fumiya; Niizato, Tadafumi; Sasaki, Yoshito; Ito, Satomi; Watanabe, Takayoshi; Dohi, Terumi; Nakanishi, Takahiro; Sakuma, Kazuyuki; Hagiwara, Hiroki; Funaki, Hironori; et al.
JAEA-Research 2019-002, 235 Pages, 2019/08
JAEA-Research-2019-002.pdf:21.04MB
The accident of the Fukushima Daiichi Nuclear Power Station (hereinafter referred to 1F), Tokyo Electric Power Company Holdings, Inc. occurred due to the Great East Japan Earthquake, Sanriku offshore earthquake, of 9.0 magnitude and the accompanying tsunami. As a result, large amount of radioactive materials was released into the environment. Under these circumstances, JAEA has been conducting Long-term Environmental Dynamics Research concerning radioactive materials released in environment, especially migration behavior of radioactive cesium since November 2012. This report is a summary of the research results that have been obtained in environmental dynamics research conducted by JAEA in Fukushima Prefecture.
Watanabe, Takayoshi; Oyama, Takuya; Ishii, Yasuo; Niizato, Tadafumi; Abe, Hironobu; Mitachi, Katsuaki; Sasaki, Yoshito
KEK Proceedings 2017-6, p.122 - 126, 2017/11
no abstracts in English
Sasaki, Yoshito; Ishii, Yasuo; Abe, Hironobu; Mitachi, Katsuaki; Watanabe, Takayoshi; Niizato, Tadafumi
The Horticulture Journal, 86(2), p.139 - 144, 2017/04
To examine the translocation of radiocesium (Cs) scattered by the Fukushima Daiichi Nuclear Power Plant accident that occurred in March 2011 to the Japanese chestnut, we investigated the autoradiography and radiocesium concentration in each part of the Japanese chestnut. The Japanese chestnut fruit has a thin skin between the kernel (cotyledons) and shell; the kernel of the fruit is edible. 
Cs concentration in each part of the fruit was found to be almost the same at about 1.0
10
Bq
kg
. Radiocesium concentration in chestnut weevil larvae found on the fruit was approximately one-seventh of that in the kernel.
Sugaya, Toshikatsu; Nakatani, Takayoshi; Sasaki, Toshihisa*; Nakamura, Yasuo*; Sakai, Akihiro; Sakamoto, Yoshiaki
JAEA-Technology 2016-036, 126 Pages, 2017/02
JAEA-Technology-2016-036.pdf:7.28MB
At the Radioactive Waste Management and Disposal Project Department Sector of Decommissioning and Radioactive Waste Management, we performed the technological study about the disposal measures of the low-level radioactive waste targeted for uranium-bearing waste and intermediate depth disposal-based waste occurring from the process of the nuclear fuel cycle.
) contaminated by radionuclides from the Fukushima Dai-ichi Nuclear Power Plant accidentSasaki, Yoshito; Abe, Hironobu; Mitachi, Katsuaki; Watanabe, Takayoshi; Ishii, Yasuo; Niizato, Tadafumi
Journal of Environmental Radioactivity, 161, p.58 - 65, 2016/09
Times Cited Count：16 Percentile：43.99(Environmental Sciences)We report the behavior of radiocesium on the tree bark and its transfer into the stemflow of chestnut in a forest in Fukushima. The radiocesium concentration is greatest in 
2-cm stem, less in 
5-mm stem, and least in the leaves. In the 2-cm stem, the radiocesium concentration of the bark was approximately 10 times that of wood. The average Cs-137 concentration of the dissolved fraction of stem flow was about 10 Bq/L; the pH was nearly constant at 5.8. A strong positive correlation was observed between the radiocesium concentration and the electrical conductivity of the dissolved fraction of stemflow; this result suggests that radiocesium and electrolytes have the same elution mechanism from the tree. Some of the particles in the particulate fraction of the stem flow was strongly adsorbed radiocesium.
Niizato, Tadafumi; Abe, Hironobu; Mitachi, Katsuaki; Sasaki, Yoshito; Ishii, Yasuo; Watanabe, Takayoshi
Journal of Environmental Radioactivity, 161, p.11 - 21, 2016/09
Times Cited Count：29 Percentile：67.86(Environmental Sciences)Estimations of radiocesium input and output budgets concerning the forest floor in a mountain forest region have been conducted in the north and central part of the Abukuma Mountains of Fukushima, after 2 to 3 year period following the TEPCO Fukushima Dai-ichi Nuclear Power Plant accident. The radiocesium input and output associated with surface washoff, throughfall, stemflow, and litterfall processes at the experimental plots have been monitored on a forest floor of evergreen Japanese cedar and deciduous Konara oak forests. The results at both monitoring locations show the radiocesium input to be 4-50 times higher than the output during the rainy season in Fukushima. These results indicate that the radiocesium tend to be preserved in the forest ecosystem due to extremely low output ratios. Thus, the associated fluxes throughout the circulation process are key issues for the projecting the environmental fate of the radiocesium levels.
Hasegawa, Noboru; Ochi, Yoshihiro; Kawachi, Tetsuya; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Kaihori, Takeshi; Morita, Toshimasa; Sasaki, Akira; Terakawa, Kota*; et al.
X-Ray Lasers 2012; Springer Proceedings in Physics, Vol.147, p.117 - 120, 2014/00
Times Cited Count：0 Percentile：0(Engineering, Electrical & Electronic)We have developed the femto-second laser pump and soft X-ray laser probe system in order to observe the dynamical processes of the femto-second laser ablation. By using this system, we succeed to obtain the temporal evolution of the soft X-ray reflectivity from the laser induced Pt surface. The results lead that the rate of decrease in the reflectivity of the probe beam has a non-linear relation with the pump laser fluence.
Hasegawa, Noboru; Ochi, Yoshihiro; Kawachi, Tetsuya; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Kaihori, Takeshi; Sasaki, Akira; Terakawa, Kota*; Minami, Yasuo*; et al.
Proceedings of SPIE, Vol.8140, p.81400G_1 - 81400G_8, 2011/10
Times Cited Count：3 Percentile：82.2(Engineering, Electrical & Electronic)We have developed a soft X-ray laser (SXRL) interferometer capable of the single-shot imaging of nano-scaled structure dynamics. The interferometer consisted of the reflection optics including double Lloyd's mirrors and focusing optics, and the interference fringes are produced on the detector surface. By using this interferometer, the initial stage (
50 ps) of the ablation process of the Pt surface pumped by a 70 fs Ti:Sapphire laser pulse was observed. The expansion speed of the surface estimated from the result (34 nm/50 ps) indicated that the nano-bubble structures were formed in the initial stage of the ablation. In order to observe the detailed dynamics, the temporal synchronization between the pump and probe pulses was improved to be 3 ps by adopting a portion of the SXRL and pump beams as the time fiducials, to which the pump and probe timing was adjusted by using the X-ray streak camera.
Sasaki, Yasuo; Torata, Shinichiro; Numata, Yoshiaki
JAEA-Review 2008-078, 51 Pages, 2009/03
JAEA-Review-2008-078.pdf:5.57MB
JAEA organizes the "Technical Committee for Geological Isolation Research & Development", which consists of specialists in relevant fields at universities and institutes, in order to facilitate planning and conducting of a program of research and development (R&D) for geological disposal of high-level radioactive waste and TRU waste at JAEA-Tokai, through reflecting technical advices and comments made from them into the program. This report presents the minutes of the third meeting held in March 2008.
Sasaki, Yasuo; Numata, Yoshiaki; Torata, Shinichiro
JAEA-Review 2008-068, 23 Pages, 2009/02
JAEA-Review-2008-068.pdf:2.73MB
The nuclear waste disposal is still in discussion as one of the key issue while we continue the sustainable atomic energy use, and it has been taking with much of the viewpoint of the social acceptance. In addition it may be said that it is the problem that the long term necessity to promote the disposal arise the subjects of the security of people who take charge of the disposal project. Also the management of knowledge with technical information between generations would become another subject in the future. To find the way out of these concerns, the practices having been tryed by the researcher group towards the student generation are reviewed in this report. The results of the opinion exchange and scientific communication with the people in the educational institution by the disposal research scientists are reviewed based on the questionnaire and discussion at a practice of schooling and lecture at high schools and universities.
Sasaki, Yasuo; Torata, Shinichiro; Numata, Yoshiaki
JAEA-Review 2008-016, 69 Pages, 2008/03
JAEA-Review-2008-016.pdf:7.79MB
In order to plan and conduct a program of research and development (R&D) for geological disposal of high-level radioactive waste in JAEA-Tokai, JAEA decided to receive technical comments and advices from the Technical Committee for geological isolation R&D. This committee, which is constituted of specialists who do not belong to JAEA, has evaluated the program, taking into account of the status of geological disposal technology in Japan as well as foreign countries. This report compiles the minutes of the second meeting held in March 2007.
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
JAEA-Review-2007-050.pdf:28.56MB
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.
Sasaki, Yasuo
JAEA-Review 2007-016, 15 Pages, 2007/03
JAEA-Review-2007-016.pdf:0.88MB
Japan Atomic Energy Agency (JAEA) has more than one thousand of short-term visitors to ENTRY and QUALITY of Tokai Research and Development Center in every year to make visitors understand the result of research and development for geological isolation of high level radioactive waste (HLW). The important opinions and questions about geological isolation of HLW from visitors were integrated. Based on them, the information of understanding activities and future needs for research and development of geological isolation were documented.
Sasaki, Yasuo; Torata, Shinichiro
JAEA-Conf 2007-004, 123 Pages, 2007/03
In order to plan and conduct a program of research and development (R&D) for geological disposal of high-level radioactive waste in JAEA-Tokai, JAEA decided to receive technical comments and advices from the Technical Committee for geological isolation R&D. This committee, which is constituted of specialists who do not belong to JAEA, has evaluated the program, taking into account of the status of geological disposal technology in Japan as well as foreign countries. This report compiles the minutes of the first meeting held in July 2006.
OKameda, Yasuo*; Sasaki, Motoya*; Usuki, Takeshi*; Otomo, Toshiya*; Ito, Keiji*; Suzuya, Kentaro; Fukunaga, Toshiharu*
Journal of Neutron Research, 11(3), p.153 - 163, 2003/09
We describe results of time-of-flight (TOF) neutron diffraction of the liquid water null-HO in order to investigate the effect of both the scattering angle and the neutron flight path ratio to the observed self-scattering intensities. An empirical inelasticity correction procedure is proposed using the self-scattering intensity observed for the null-HO.
Makino, Tsutomu; Koakutsu, Masayuki; Nakazawa, Osamu; Sasaki, Yasuo; Kato, Hiroshi
Saikuru Kiko Giho, (20), 124 Pages, 2003/00
None
Kuroda, Toshimasa*; Sato, Kazuyoshi; Akiba, Masato; Ezato, Koichiro; Enoeda, Mikio; Osaki, Toshio*; Kosaku, Yasuo; Sato, Satoshi; Sato, Shinichi*; Suzuki, Satoshi*; et al.
JAERI-Tech 2002-044, 25 Pages, 2002/03
JAERI-Tech-2002-044.pdf:2.68MB
no abstracts in English
Sasamoto, Hiroshi; Seo, Toshihiro; Yui, Mikazu; Sasaki, Yasuo
PNC TN8410 96-203, 66 Pages, 1996/10
None
