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Iwamoto, Osamu; Iwamoto, Nobuyuki; Kunieda, Satoshi; Minato, Futoshi; Nakayama, Shinsuke; Abe, Yutaka*; Tsubakihara, Kosuke*; Okumura, Shin*; Ishizuka, Chikako*; Yoshida, Tadashi*; et al.
Journal of Nuclear Science and Technology, 60(1), p.1 - 60, 2023/01
Times Cited Count:318 Percentile:99.99(Nuclear Science & Technology)Nakayama, Takuya; Nomura, Mitsuo; Mita, Yutaka; Yonekawa, Hitoshi*; Bunbai, Misako*; Yaita, Yumi*; Murata, Eiichi*; Hosaka, Katsumi*; Sugitsue, Noritake
Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 8 Pages, 2019/05
Clearance of contaminated metal is important for recycling and volume reduction of radioactive waste. Among applicable decontamination technologies, immersion method with ultrasonic cleaning is considered to be effective for metal materials having various shapes. in this study is to demonstrate decontamination of carbon steel contaminated by uranium hexafluoride to the target level for clearance (less than 0.04 Bq/cm
), and minimize secondary waste. In this test, acidic electrolytic water, dilute hydrochloric acid, dilute sulfuric acid and ozone water with various pH and redox potential were used as decontamination solutions to be tested. We found that acidic electrolytic water is effective solution for decontamination of carbon steel contaminated by uranium hexafluoride. It could be decontaminate less than target level for clearance, and reduced secondary waste relatively.
Sanada, Yukihisa; Munakata, Masahiro; Mori, Airi; Ishizaki, Azusa; Shimada, Kazumasa; Hirouchi, Jun; Nishizawa, Yukiyasu; Urabe, Yoshimi; Nakanishi, Chika*; Yamada, Tsutomu*; et al.
JAEA-Research 2016-016, 131 Pages, 2016/10
By the nuclear disaster of Fukushima Daiichi Nuclear Power Station (FDNPS), Tokyo Electric Power Company (TEPCO), caused by the East Japan earthquake and the following tsunami occurred on March 11, 2011, a large amount of radioactive materials was released from the NPS. After the nuclear disaster, airborne radiation monitoring using manned helicopter was conducted around FDNPS. In addition, background dose rate monitoring was conducted around Sendai Nuclear Power Station. These results of the aerial radiation monitoring using the manned helicopter in the fiscal 2015 were summarized in the report.
Fujita, Satoshi*; Kuma, Kenshi*; Ishikawa, Satoko*; Nishimura, Shotaro*; Nakayama, Yuta*; Ushizaka, Satomi*; Isoda, Yutaka*; Otosaka, Shigeyoshi; Aramaki, Takafumi*
Journal of Geophysical Research, 115(C12), p.C12001_1 - C12001_12, 2010/12
Times Cited Count:16 Percentile:37.40(Oceanography)Vertical distributions of dissolved iron (D-Fe, less than 0.22 micrometer fraction), total iron (T-Fe, unfiltered), and chemical and biological components (e.g., nutrients) in seawater were determined at seven stations in the Japan Sea to understand the mechanisms that control iron behavior. Distributions of the D-Fe were characterized by surface depletion, mid-depth maxima, then slight decrease with depth in deep water and uniform concentration in bottom water because of biological uptake in the surface water and release from microbial decomposition of sinking organic matter in mid-depth water. The T-Fe concentrations in the deep-water column were variable with different T-Fe levels among stations and depths. We found a significant relationship of the exponential increase in the T-Fe concentrations with decreasing water transmittance, resulting from the iron supply into the deep and bottom waters due to the lateral transport of resuspended sediment from the continental slope.
Ito, Toshimichi; Kawamura, Hideyuki; Nakayama, Tomoharu*; Shima, Shigeki*; Onishi, Mitsuyo*; Isoda, Yutaka*
Proceedings of International Workshop on Monitoring and Forecasting of the Rapid Change in Ocean-Atmosphere Environment in the East Asia, p.13 - 14, 2007/11
The volume transport of the Tsugaru Warm Current (TgWC) from April 2000 to June 2002, which was estimated based on the ferry-borne ADCP observation was examined in this study. The estimated transport varied from about 0.6 Sv to 2.5 Sv (=10
m
s
), and the mean value was estimated to be about 1.3 Sv with
0.3 Sv showing the similar level as that in the preliminary result. The temporal variation with a period of about 20-30 days seemed to be remarkable in the anterior half of this observation period rather than seasonal variation. By contrast, the seasonal variation was dominant in the posterior half in which the minimum and maximum values appear in the spring and autumn, respectively. The temporal change of the transport showed good correlation with the sea level differences around the strait as expected. In addition, the present result suggests that the change of local wind around the strait also lead in part of the change of the transport.
Ito, Toshimichi; Kawamura, Hideyuki; Onishi, Mitsuyo*; Isoda, Yutaka*; Nakayama, Tomoharu*; Shima, Shigeki*
Proceedings of 14th PAMS/JECSS Workshop, p.222 - 223, 2007/05
no abstracts in English
In, Teiji*; Nakayama, Tomoharu*; Matsuura, Yasutaka*; Shima, Shigeki*; Ishikawa, Yoichi*; Awaji, Toshiyuki*; Kobayashi, Takuya; Kawamura, Hideyuki; Togawa, Orihiko; Toyoda, Takahiro*
Proceedings of International Symposium on Environmental Modeling and Radioecology, p.58 - 64, 2007/03
The northwestern part of the Pacific Ocean off the Shimokita Peninsula assumes a complex water mass structure. It is necessary to accurately reproduce the striking circulation patterns and the complicated water mass structures in this area with an ocean general circulation model. We have planned to make use of a one-way nesting method. To initialize the forecast system, we use a 4-dimensional variational method of data assimilation. The assimilated data consist of hydrographic observations collected through the Global Temperature-Salinity Profile Program, sea surface temperature and sea surface height data observed by satellites. A forecast experiment on the basis of oceanographic observations made in 2003 illustrates the good performance of our system. We shall focus, in particular, on the shift from the coastal mode to the gyre mode and vice versa.
Kuroda, Hiroshi*; Isoda, Yutaka*; Onishi, Mitsuyo*; Iwahashi, Masayuki*; Sato, Chizuru*; Nakayama, Tomoharu*; Ito, Toshimichi; Iseda, Kenichi*; Nishizawa, Keisuke*; Shima, Shigeki*; et al.
Umi No Kenkyu, 13(6), p.553 - 564, 2004/11
no abstracts in English
Onishi, Mitsuyo*; Isoda, Yutaka*; Kuroda, Hiroshi*; Iwahashi, Masayuki*; Sato, Chizuru*; Nakayama, Tomoharu*; Ito, Toshimichi; Iseda, Kenichi*; Nishizawa, Keisuke*; Shima, Shigeki*; et al.
Hokkaido Daigaku Suisan Kagaku Kenkyu Iho, 55(2), p.105 - 119, 2004/10
Transport variations and characteristics of tidal currents in the Tsugaru Strait (TS) are investigated using the ship-mounted ADCP data obtained during October 29, 1999 - March 31, 2000. The Tsugaru Strait connects the North Pacific Ocean (NPO) and Japan/East Sea (JES), and is a main output for Tsushima Warm Current (TWC) in the JES. The strong northeastwards mean current was found in the center of the strait, and counter flows exist near the Hokkaido and Honshu coasts. The estimated mean net eastward transport is 1.8 Sv (1Sv=10
m
s
). In the TS, the transports of K1 and M2 across the strait are 0.72 Sv and 0.52 Sv, respectively. From the phase analysis, it is understood the K1 is progressive wave-like while the M2 is standing wave-like. We also find a significant barotropic fortnightly oscillation. The Mf tide is more energetic along the JES coast with the amplitude of 1-3cm, while the Mf tide amplitudes in the NPO are less than 1 cm. It is inferred that observed fortnightly oscillation may be generated by the difference of Mf tide amplitude between both sides of the TS.
Pb(
He,
) reaction at 410 MeVZegers, R. G. T.*; Abend, H.*; Akimune, Hidetoshi*; Van den Berg, A. M.*; Fujimura, Hisako*; Fujita, Hirohiko*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Gal
s, S.*; Hara, Keigo*; et al.
Nuclear Physics A, 731, p.121 - 128, 2004/02
Times Cited Count:11 Percentile:55.80(Physics, Nuclear)no abstracts in English
Ito, Toshimichi; Togawa, Orihiko; Onishi, Mitsuyo*; Isoda, Yutaka*; Nakayama, Tomoharu*; Shima, Shigeki*; Kuroda, Hiroshi*; Iwahashi, Masayuki*; Sato, Chizuru*
Geophysical Research Letters, 30(13), p.11_1 - 11_4, 2003/10
The variation of velocity and volume transport of the Tsugaru Warm Current (TWC) is investigated based on the data of continuous and cross-sectional current monitoring in the Tsugaru Strait. During November 1999 - March 2000, the structure of the velocity transection across the strait was almost stable in which the TWC occupied the central part of the strait, while the returning flows existed in the northern and southern part of the strait, and these indicate a totally declining trend. The volume transport of the TWC varies from 2.1 to 1.1 Sv, with the mean value of 1.5 Sv, following the variation of the TWC. The temporal variation of the volume transport shows a linear correlation with that of the sea level difference between the Japan Sea and the Pacific Ocean. The contribution of the sea level difference to the volume transport is estimated to be roughly 70 %.
Pb(
He,
) reaction at 410 MeVZegers, R. G. T.; Abend, H.*; Akimune, Hidetoshi*; Van den Berg, A. M.*; Fujimura, Hisako*; Fujita, Hirohiko*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Gal
s, S.*; Hara, Keigo*; et al.
Physical Review Letters, 90(20), p.202501_1 - 202501_4, 2003/05
Times Cited Count:50 Percentile:84.63(Physics, Multidisciplinary)no abstracts in English
Kuroda, Hiroshi*; Isoda, Yutaka*; Onishi, Mitsuyo*; Iwahashi, Masayuki*; Sato, Chizuru*; Nakayama, Tomoharu*; Ito, Toshimichi; Iseda, Kenichi*; Nishizawa, Keisuke*; Shima, Shigeki*; et al.
Umi No Kenkyu, 12(2), p.195 - 214, 2003/03
Variabilities of the periodical current fluctuations on the shelf in Hidaka Bay were examined with use of ferry-mounted ADCP data obtained during 2000-2001. As the result of analysis, (1) three periodical variations around 10-, 25- and 60-day period are found, (2) the horizontal phase lag of these variations is little along the ship track, and the vertical phase lag is little at 10- and 25-day variations while several-day at 60-day variation, and (3) the 10-day variation shows coherent cross-correlation between current and wind.
clusters in
Li and
LiNakayama, Shintaro*; Yamagata, Tamio*; Akimune, Hidetoshi*; Daito, Izuru*; Fujimura, Hisako*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Fushimi, Kenichi*; Greenfield, M. B.*; Kori, Hideki*; et al.
Physical Review Letters, 87(12), p.122502_1 - 122502_4, 2001/09
Times Cited Count:24 Percentile:71.66(Physics, Multidisciplinary)no abstracts in English
HeNakayama, Shintaro*; Yamagata, Tamio*; Akimune, Hidetoshi*; Daito, Izuru*; Fujimura, Hisako*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Fushimi, Kenichi*; Inomata, Toru*; Kori, Hideki*; et al.
Physical Review Letters, 85(2), p.262 - 265, 2000/07
Times Cited Count:76 Percentile:88.93(Physics, Multidisciplinary)no abstracts in English
Okawa, Yoshinao; Murano, Yoshihiro*; Okada, Kenichi*; Kawakami, Kunio*; Izumi, Keisuke*; ; Sasaki, Takashi*;
Heisei 12-Nendo Denki Setsubi Gakkai Zenkoku Taikai Koen Rombunshu, p.315 - 316, 2000/00
no abstracts in English
Nakayama, Takeshi*; Yamamoto, Masahiro; Abe, Mitsushi*; Shibata, Takatoshi; Otsuka, Michio*; Akiyama, Takashi*; Sato, K.*; Kikuchi, Kazuo; Wada, Y.*; Koike, Tsuneyuki; et al.
Proceedings of the 18th IEEE/NPSS Symposium on Fusion Engineering (SOFE '99), p.227 - 230, 1999/10
no abstracts in English
Krasznahorkay, A.*; Fujiwara, Mamoru; Van Aarle, P.*; Akimune, Hidetoshi; Daito, Izuru*; Fujimura, Hisako*; Fujita, Yoshitaka*; Harakeh, M. N.*; Inomata, Toru*; J
necke, J.*; et al.
Physical Review Letters, 82(16), p.3216 - 3219, 1999/04
Times Cited Count:201 Percentile:96.73(Physics, Multidisciplinary)no abstracts in English
Asahina, Kiyoshi*; Soya, Masataka*; Ogawa, Hikaru*; Akasaka, Takayuki*; Iwata, Toshio*; Fukutome, Yutaka*; Nakayama, Jumpei*
PNC TJ4058 89-005, 178 Pages, 1989/06
None
; ; ; Adachi, Junichi*; ; ; ; Kuroda, Toshimasa*; ; ; et al.
JAERI-M 88-083, 426 Pages, 1988/05
no abstracts in English