Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Sanada, Yukihisa; Miyamoto, Kenji*; Ochi, Kotaro; Matsuzaki, Koji*; Ogawa, Toshihiro*; Senga, Yasuhiro*
Kaiyo Riko Gakkai-Shi, 24(2), p.9 - 18, 2018/12
Seven years passed since Fukushima Dai-ichi Nuclear Power Station accident which was caused large amount of radionuclide release to the sea. Elucidation of behavior mechanism of radiocesium in the seabed is required for restarting fishing industry. We developed radiation detection system using the unmanned surface vehicle for in-situ measurement of radiocesium concentration in seabed sediment. This system is able to automatically navigate to measurement point and obtain the radiation data on the bottom sediment. The detector was calibrated by comparing the actual sediment samples. The periodical measurement off-shore the Fukushima Prefecture was performed using developed this system. As these results, distribution of radiocesium concentration was changed due to oceanographic condition. However, radiocesium inventory was tendency to decrease according to radiocesium half-life in measurement area. This system is effective for elucidation of behavior mechanism of radiocesium because it can easily measure the radiocesium concentration in the bottom sediment.
-ray irradiation facilitiesKaneko, Hirohisa; Haruyama, Yasuyuki; Haneda, Noriyuki; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Kanazawa, Takao; Kojima, Takuji; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; et al.
JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 192, 2008/11
The accelerator served mainly for graft-polymerization for new material development, radiation effect study on semiconductors and various experiments of visiting users. The annual operation time of the electron accelerator is 706.3h. The Co-60 -ray irradiation facilities consist of three buildings (8 rooms) and cover a wide dose-rate range from 0.04 Gy/h to 20 kGy/h with eight irradiation cells. The annual operation time for the first, second cobalt irradiation facilities and food irradiation facility is 23,433h, 9,010h and 10,631h.
-ray irradiation facilitiesKaneko, Hirohisa; Haruyama, Yasuyuki; Haneda, Noriyuki; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Kanazawa, Takao; Kojima, Takuji; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; et al.
JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 193, 2008/11
An electron accelerator and three -ray irradiation facilities were operated for various research subjects as operation plan in FY 2007 without serious trouble. The number of research subjects for the electron accelerator and -ray irradiation facilities is 505 and 1174, respectively. The number of experiment subject at the electron accelerator increased in the research fields of environment and nuclear facilities, and decreased in the field of heat resist. Also, the number at -ray irradiation facilities increased in the field of resource & bio-technology, and decreased in the field of nuclear facilities.
Kato, Yuko; Umebayashi, Eiji; Okimoto, Yutaka; Okuda, Eiichi; Takayama, Koichi; Ozawa, Takayuki; Maeda, Seiichiro; Matsuzaki, Masaaki; Yoshida, Eiichi; Maeda, Koji; et al.
JAEA-Research 2007-019, 56 Pages, 2007/03
JAEA-Research-2007-019.pdf:6.79MB
In order to resume the System Startup Test (SST) of Monju, replacement fuel have to be loaded in exchange for some of initial fuel now loaded in the core to compensate core reactivity lost by decay of Pu-241 in them. The replacement fuel were being stored either in sodium in an ex-vessel storage tank or in air in a storage rack for about 10 years since their fabrication. The initial fuel were irradiated during the SST which was suspended in the end of 1995 and then stayed being loaded in the sodium-circulated core. As this long-term storage and loading may deteriorate mechanical integrity of the assemblies, a study has been made thoroughly on its thermal-hydraulic, structural and material effects on them that might be caused by irradiation in the core, sodium and mechanical environment. The study has shown that the mechanical integrity of them is well maintained even with this long-term storage and loading.
Oikawa, Teruki; Umeda, Koji; Kanazawa, Sunao; Matsuzaki, Tatsuji*
Journal of Mineralogical and Petrological Sciences, 101(1), p.23 - 28, 2006/02
Times Cited Count：2 Percentile：4.3(Mineralogy)The authors report biotite K-Ar, zircon FT, and apatite FT ages from four sites in the Ichifusayama Granodiorite in the Outer Zone acidic rocks of Southwest Japan, Southern Kyushu. All the K-Ar ages and FT ages are concentrated on 13-10Ma. The difference in the apatite FT ages was caused by an influence of paleotopography such as a deep valley. The rapid cooling of the granodiorite in ca. 13 Ma occurred by uplift throughout the Outer Zone of Southwest Japan in Kyushu. It is considered that obduction to the Philippine Sea Plate of the Outer Zone of Kyushu also occurred in ca. 13 Ma. It is considered that obduction to the Philippine Sea Plate of the Outer Zone of Kyushu also occurred in ca. 13 Ma.
Takahashi, Koji; Komatsuzaki, Manabu*
JAERI-Research 2000-054, 23 Pages, 2001/03
JAERI-Research-2000-054.pdf:1.37MB
no abstracts in English
Oikawa, Teruki; Umeda, Koji; Matsuzaki, Tatsuji*
no journal, ,
K-Ar and FT analyses were carried out on biotite, zircon and apatite from the granitic rocks in Kashiwazima district, western Shikoku in order to reveal the cooling history. These ages suggest rapid cooling of the granitic rocks in the temperature range to 100
C from 300C in 14-13Ma.
Takahashi, Koji; Abe, Ganji; Isozaki, Masami; Komatsuzaki, Manabu*; Abe, Teruo*; Iida, Hiromasa*; Kobayashi, Noriyuki*; Kajiwara, Ken; Sakamoto, Keishi
no journal, ,
Design change from toroidal to poloidal beam steering of equatorial launcher has been proposed by ITER Organization. This design change has large design impact on blanket shield modules (BSM), millimeter wave path and components. In addition, heat resistance, structural integrity, nuclear shielding capability and etc. for the modified design are needed to be re-evaluated. At first, BSM design modification was implemented since it had the extraordinary impact. Then, the structural integrity against electromagnetic force and nuclear shielding capability was evaluated. The analysis shows that moment of almost all modules and the entire launcher structure become less than the design limit. Regarding to nuclear shielding capability, it was obtained that residual dose rate at the launcher backend was reduced by 20%. However, the residual dose from the surroundings was also revealed.
Takahashi, Koji; Abe, Ganji; Isozaki, Masami; Ikeda, Ryosuke; Oda, Yasuhisa; Kajiwara, Ken; Sakamoto, Keishi; Kobayashi, Noriyuki*; Iida, Hiromasa*; Komatsuzaki, Manabu*; et al.
no journal, ,
It was analytically obtained that electron cyclotron current drive efficency at 
=0.4
0.6 can be doubled modifying the steering function of millimeter wave launching from the equatorial port from toroidally to poloidally. The design modification of the ITER equatorial launcher enhancing ECCD function is implemented. The millimeter wave design satisfying transmission efficiency more than 99% with the required ploidal beam steering capability is successfully obtained and reflected to the launcher structural design. The millimeter wave design optimization, BSM design modification to allow the required polidal beam steering capability and so on are reported in detail at the conference.
Koga, Yasuhiko*; Kaira, Kyoichi*; Yamada, Masanobu*; Dobashi, Kunio*; Matsuzaki, Shinichi*; Hisada, Takeshi*; Koka, Masashi; Yamada, Naoto; Sato, Takahiro; Yokoyama, Akihito; et al.
no journal, ,
Shidara, Hiroyuki; Takahashi, Koji; Komatsuzaki, Manabu*; Isozaki, Masami; Kobayashi, Noriyuki*; Abe, Teruo*; Abe, Ganji; Oda, Yasuhisa; Ikeda, Ryosuke; Kobayashi, Takayuki; et al.
no journal, ,
In order to validate the millimeter wave design procedure, the EL mock-up has been constructed and the low power test has been carried out by using mW-level low power RF oscillators. The test has been carried out with critical four edged beams instead of all eight beams in the upper waveguide unit. The measured data has been compared with design at several important locations in the launcher and after the launcher exit with steering mirror angle changed. The comparison of the measured beams propagation and the design shows good agreement for the beam sizes and the beam orientation performance. The quantitative evaluations has been carried out and the design procedure's reasonability has been confirmed.
