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Saito, Takumi*; Nishi, Shusaku*; Amano, Yuki; Beppu, Hikari*; Miyakawa, Kazuya
ACS ES&T Water (Internet), 3(12), p.4103 - 4112, 2023/12
Koarashi, Jun; Nishimura, Shusaku; Nakanishi, Takahiro; Atarashi-Andoh, Mariko; Takeuchi, Erina; Muto, Kotomi
Chemosphere, 165, p.335 - 341, 2016/12
Times Cited Count：39 Percentile：77.69(Environmental Sciences)We established field lysimeters in a Japanese deciduous broad-leaved forest soon after the Fukushima nuclear accident to continuously monitor the downward transfer of 
Cs at three depths: the litter-mineral soil boundary and depths of 5 cm and 10 cm in the mineral soil. Observations were conducted at two sites within the forest from May 2011 to May 2015. Results revealed similar temporal and depth-wise variations in Cs downward fluxes for both sites. The Cs downward fluxes generally decreased year by year at all depths, indicating that Cs was rapidly leached from the forest-floor litter layer and was then immobilized in the upper (0-5 cm) mineral soil layer through its interaction with clay minerals. The decreased inventory of mobile (or bioavailable) Cs observed during early stages after deposition indicates that the litter-soil system in the Japanese deciduous forest provides only a temporary source for Cs recycling in plants.
Cs in a forested catchment affected by the Fukushima Daiichi Nuclear Power Plant accidentMatsunaga, Takeshi; Nakanishi, Takahiro; Atarashi-Andoh, Mariko; Takeuchi, Erina; Muto, Kotomi; Tsuzuki, Katsunori; Nishimura, Shusaku; Koarashi, Jun; Otosaka, Shigeyoshi; Sato, Tsutomu*; et al.
Journal of Radioanalytical and Nuclear Chemistry, 310(2), p.679 - 693, 2016/11
Times Cited Count：6 Percentile：49.05(Chemistry, Analytical)Particulate Cs in stream water was collected continuously for two years in order to assess the long-term trend of the Cs discharge from the forest environment. Sampling was conducted from December 2011 to December 2013 in a mountainous stream, which received the Cs from the Fukushima Daiichi Nuclear Power Plant accident. A seasonal increase in fluvial transport load of particulate Cs associated with suspended solids (SS) was observed in August and September when rainfall was abundant. The particulate Cs concentration decreased at a faster rate than the rate due to radioactive decay. This decrease might be resulted from redistribution of the easily eroded and polluted soil surface due to heavy rain events such as typhoons. These findings indicate that the particulate Cs load was subject to the inter-annual variations in rainfalls, and decreased gradually over a long period of time due to a decrease in Cs concentration in SS.
Muto, Kotomi; Atarashi-Andoh, Mariko; Takeuchi, Erina; Nishimura, Shusaku; Koarashi, Jun; Tsuzuki, Katsunori; Nakanishi, Takahiro; Matsunaga, Takeshi
KEK Proceedings 2015-4, p.252 - 257, 2015/11
As a result of the Fukushima Daiichi Nuclear Power Plant accident, a large amount of radiocesium released into the atmosphere was deposited in forests. This study estimated the monthly trend in the fluvial discharges of radiocesium from a forest. The study site was a forested catchment in Kitaibaraki City. Radiocesium in river water was collected with a filtration system as both particulate and dissolved components. Filters and columns including dissolved Cs absorbent were replaced every month. The collected suspended solids were sieved into 2000-3000 
m, 500-2000 m, 75-500 m, and 
75 m fractions. The Cs concentrations in the samples were measured using 
-ray spectrometry with Ge semiconductor detectors. The Cs discharge increased with the river water discharge. The particulate Cs discharge was dominant in both 2013 and 2014. The Cs discharge rate of the dissolved component increased in winter, when the river water discharge decreased.
Matsunaga, Takeshi; Nakanishi, Takahiro; Atarashi-Andoh, Mariko; Takeuchi, Erina; Tsuzuki, Katsunori; Nishimura, Shusaku; Koarashi, Jun; Otosaka, Shigeyoshi; Sato, Tsutomu*; Nagao, Seiya*
Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1291 - 1295, 2015/02
Times Cited Count：3 Percentile：25.64(Chemistry, Analytical)An innovative, yet simple method for the passive collection of radioactive materials in river water has been developed and validated. The method employes large filter vessels, containing multiple cartridge filters. River water is led to the system naturally using a drop of the riverbed by hose from upstream. This method makes long-term, unmanned monitoring possible. In addition to regular radioactivity analyses, this method provides an opportunity for the characterization of suspended materials based on its ample collection quantities (more than several tens of grams). This method may also be applicable to sediment-bound chemicals.
Ohashi, Hirofumi; Inaba, Yoshitomo; Nishihara, Tetsuo; Inagaki, Yoshiyuki; Takeda, Tetsuaki; Hayashi, Koji; Katanishi, Shoji; Takada, Shoji; Ogawa, Masuro; Shiozawa, Shusaku
Journal of Nuclear Science and Technology, 41(3), p.385 - 392, 2004/03
Times Cited Count：17 Percentile：72.26(Nuclear Science & Technology)Prior to construction of a HTTR hydrogen production system, a mock-up test facility was constructed to investigate transient behavior of the hydrogen production system and to establish system controllability. The Mock-up test facility with a full-scale reaction tube is an approximately 1/30 scale model of the HTTR hydrogen production system and an electric heater is used as a heat source instead of a reactor. Before the mock-up test, a performance test of the test facility was carried out in the same pressure and temperature conditions as those of the HTTR hydrogen production system to investigate its performance such as hydrogen production ability, controllability and so on. It was confirmed that hydrogen was stably produced with a hot helium gas about 120Nm
/h which satisfy the design value and thermal disturbance of helium gas during the start-up could be mitigated within the design value by using a steam generator.
Kunitomi, Kazuhiko; Katanishi, Shoji; Takada, Shoji; Takizuka, Takakazu; Nakata, Tetsuo; Yan, X.; Takei, Masanobu; Kosugiyama, Shinichi; Shiozawa, Shusaku
Nihon Genshiryoku Gakkai Wabun Rombunshi, 1(4), p.352 - 360, 2002/12
no abstracts in English
Takada, Shoji; Takizuka, Takakazu; Kunitomi, Kazuhiko; Yan, X.; Katanishi, Shoji; Kosugiyama, Shinichi; Shiozawa, Shusaku
Nihon Kikai Gakkai Dai-8-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.189 - 192, 2002/00
no abstracts in English
Katanishi, Shoji; Kunitomi, Kazuhiko; Takada, Shoji; Nakata, Tetsuo; Takizuka, Takakazu; Shiozawa, Shusaku
Nihon Kikai Gakkai Dai-8-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.185 - 188, 2002/00
no abstracts in English
Kunitomi, Kazuhiko; Katanishi, Shoji; Takada, Shoji; Takizuka, Takakazu; Yan, X.; Nakata, Tetsuo; Takei, Masanobu; Kosugiyama, Shinichi; Shiozawa, Shusaku
Nihon Kikai Gakkai Dai-8-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.181 - 184, 2002/00
no abstracts in English
Kunitomi, Kazuhiko; Katanishi, Shoji; Shiozawa, Shusaku
Nihon Genshiryoku Gakkai-Shi, 43(11), p.1085 - 1099, 2001/11
no abstracts in English
Miyamoto, Yoshiaki; Shiozawa, Shusaku; Ogawa, Masuro; Inagaki, Yoshiyuki; Katanishi, Shoji; Nishihara, Tetsuo; Shimizu, Saburo
Hydrogen Energy Progress 13 (Proceedings of the 13th World Hydrogen Energy Conference), p.297 - 302, 2000/06
no abstracts in English
Shiozawa, Shusaku; Ogawa, Masuro; Inagaki, Yoshiyuki; Katanishi, Shoji; Takeda, Tetsuaki; Nishihara, Tetsuo; Shimizu, Saburo; Ohashi, Hirofumi; Miyamoto, Yoshiaki
Proceedings of 12th Pacific Basin Nuclear Conference (PBNC 2000) (CD-ROM), 10 Pages, 2000/01
no abstracts in English
Yan, X.; Shiozawa, Shusaku; Kunitomi, Kazuhiko; Muto, Yasushi; Miyamoto, Yoshiaki; Katanishi, Shoji
Proceedings of 8th International Conference on Nuclear Engineering (ICONE-8) (CD-ROM), p.8 - 0, 2000/00
no abstracts in English
Enokido, Yuji*; *; *; Onishi, Nobuaki; ; Shiozawa, Shusaku
Nihon Genshiryoku Gakkai-Shi, 31(7), p.742 - 772, 1989/07
no abstracts in English
Takeuchi, Erina; Atarashi-Andoh, Mariko; Nishimura, Shusaku; Nakanishi, Takahiro; Tsuzuki, Katsunori; Koarashi, Jun; Matsunaga, Takeshi
no journal, ,
no abstracts in English
Takeuchi, Erina; Atarashi-Andoh, Mariko; Nishimura, Shusaku; Nakanishi, Takahiro; Tsuzuki, Katsunori; Koarashi, Jun; Matsunaga, Takeshi
no journal, ,
no abstracts in English
Nishimura, Shusaku; Atarashi-Andoh, Mariko; Koarashi, Jun; Nakanishi, Takahiro; Matsunaga, Takeshi
no journal, ,
no abstracts in English
Takeuchi, Erina; Atarashi-Andoh, Mariko; Koarashi, Jun; Nishimura, Shusaku; Muto, Kotomi; Tsuzuki, Katsunori; Nakanishi, Takahiro; Matsunaga, Takeshi
no journal, ,
no abstracts in English
Nishi, Shusaku*; Saito, Takumi*; Watanabe, Yusuke; Miyakawa, Kazuya
no journal, ,
no abstracts in English
