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Kubota, Tomohiro; Kuroda, Hisao*; Watanabe, Mirai*; Takahashi, Akiko*; Nakazato, Ryoji*; Tarui, Mika*; Matsumoto, Shunichi*; Nakagawa, Keita*; Numata, Yasuko*; Ouchi, Takao*; et al.
Atmospheric Environment, 243, p.117856_1 - 117856_9, 2020/12
Times Cited Count：3 Percentile：15.82(Environmental Sciences)The dry and wet depositions of atmospheric ammonia (NH
) is one of the important pathways of nitrogen loads to aquatic ecosystems. Crop and livestock agriculture, one of the largest emitters of NH in Asian countries, are known to cause high spatial and seasonal variation of NH and influence the surrounding lake basin areas via its dry and wet deposition. However, the spatial characteristics of the NH concentration in basin scale are not completely understood for regulation in NH emission. Here we aim to clarify dominant factors of spatial and seasonal variations of the NH concentration in a eutrophic lake basin surrounded by agricultural areas in Japan. Passive sampling over various land use categories in the basin was conducted at 36 sites in total from October 2018 to January 2020. Interestingly, the observed NH concentration near the livestock houses were higher in winter than summer, which was inconsistent with knowledge of seasonal changes of current NH emission inventory based on temperature-driven volatilization process. Comparing monthly NH concentrations with various meteorological factors, we suggested the importance of seasonal advection of NH from high emission sources to which has been rarely paid attention by the previous past studies. As for this, should be considered for lake ecosystem management since deposition of NH is known to be closely related to the ecological processes such as phytoplankton blooming.
-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accidentSaito, Kimiaki; Tanihata, Isao*; Fujiwara, Mamoru; Saito, Takashi*; Shimoura, Susumu*; Otsuka, Takaharu*; Onda, Yuichi*; Hoshi, Masaharu*; Ikeuchi, Yoshihiro*; Takahashi, Fumiaki; et al.
Journal of Environmental Radioactivity, 139, p.308 - 319, 2015/01
Times Cited Count：224 Percentile：98.8(Environmental Sciences)Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10
no abstracts in English
Sakashita, Tetsuya; Hamada, Nobuyuki*; Kawaguchi, Isao*; Ouchi, Noriyuki; Hara, Takamitsu*; Kobayashi, Yasuhiko; Saito, Kimiaki
PLOS ONE (Internet), 8(7), p.e70291_1 - e70291_10, 2013/07
Times Cited Count：7 Percentile：33.64(Multidisciplinary Sciences)Clonogenicity gives important information about the cellular reproductive potential following ionizing irradiation. We firstly plotted the experimentally determined colony size distribution of abortive colonies in irradiated normal human fibroblasts, and found the linear relationship on the log-log plot. By applying the simple model of branching processes to the linear relationship, we found the persistent reproductive cell death (RCD) over several generations following irradiation. To verify the estimated probability of RCD, abortive colony size distribution (
15 cells/colony) and the surviving fraction were simulated by the Monte Carlo computational approach. Radiation-induced RCD (i.e. excess probability) lasted over 16 generations and mainly consisted of two components in the early and late phases. We found that short-term RCD is critical to the abortive colony size distribution, and long-lasting RDC is important for the dose response of the surviving fraction.
Kondo, Masaaki; Kimishima, Satoru*; Emori, Koichi; Sekita, Kenji; Furusawa, Takayuki; Hayakawa, Masato; Kozawa, Takayuki; Aono, Tetsuya; Kuroha, Misao; Ouchi, Hiroshi
JAEA-Technology 2008-062, 46 Pages, 2008/10
JAEA-Technology-2008-062.pdf:11.62MB
The reactor containment of HTTR is tested to confirm leak-tight integrity of itself. "Type A test" has been conducted in accordance with the standard testing method in JEAC4203 since the preoperational verification of the containment was made. Type A tests are identified as basic one for measuring containment leakage rate, it costs much, however. Therefore, the test program for HTTR was revised to adopt an efficient and economical alternatives including "Type B and Type C tests". In JEAC4203-2004, following requirements are specified for adopting alternatives: upward trend of leakage rate by Type A test due to aging should not be recognized; criterion of combined leakage rate with Type B and Type C tests should be established; the criteria for Type A test and combined leakage rate test should be satisfied; correlation between the leakage rates by Type A test and combined leakage rate test should be recognized. Considering the performances of the tests, the policies of corresponding to the requirements were developed, which were accepted by the regulatory agency. This report presents an outline of the tests, identifies issues on the conventional test and summarizes the policies of corresponding to the requirements and of implementing the tests based on the revised program.
Sekita, Kenji; Furusawa, Takayuki; Emori, Koichi; Ishii, Taro*; Kuroha, Misao; Hayakawa, Masato; Ouchi, Hiroshi
JAEA-Technology 2008-057, 45 Pages, 2008/08
JAEA-Technology-2008-057.pdf:12.0MB
A carbon steel used is used for the main material for the components and pipings of the pressurized water cooling system etc. that are the reactor cooling system of the HTTR. Water quality is managed by using the hydrazine in the coolant of the water cooling system to prevent corrosion of the components and deoxidize the coolant. Also, regular analysis is carried out for the confirmation of the water quality. The following results were obtained through the water quality analysis. (1) In the pressurized water cooling system, the coolant temperature rises higher due to the heat removal of the primary coolant. So, the ammonia was formed in the thermal decomposition of the hydrazine. The electric conductivity increased, while the concentration of the hydrazine decreased, there was no problem as the plan it. (2) Thermal decomposition of the hydrazine was not occurred in the auxiliary water cooling system and vessel cooling system because of the coolant temperature was low. (3) An indistinct procedure is clarified and procedure of water quality analysis was established in the HTTR. (4) It is assumed that the corrosion of the components in these water cooling system hardly occurred from measurement results of dissolved oxide and chloride ion. Thus, the water quality was managed enough.
Sekita, Kenji; Kuroha, Misao; Emori, Koichi; Kondo, Masaaki; Ouchi, Hiroshi; Shinozaki, Masayuki
JAEA-Technology 2008-002, 49 Pages, 2008/03
JAEA-Technology-2008-002.pdf:9.21MB
Graphite structures are used as one of the HTTR core internal structures. Graphite structures have high heat resistant property but its mechanical strength degrades easily by oxidization. To prevent the oxidization of graphite structures, impurity concentrations in the coolant of helium are controlled strictly. The helium sampling system is installed to measure the impurity concentrations in the helium. At gas compressor in helium sampling system, seal-oil leak at rod seal mechanism was occurred. The causes are degradation of seal material and contaminant abrasion powder of grand-packing. As these countermeasure, material of seal material was changed and contaminant was decreased. As the result long term operation is enabled. Moreover, reliable data can be obtained and efficient impurity control is enabled due to renewal of data acquisition control computer of gas chromatograph mass spectrometer and improvement of liquid nitrogen trap.
Matsuda, Makoto; Sataka, Masao; Takeuchi, Suehiro; Tsukihashi, Yoshihiro; Hanashima, Susumu; Abe, Shinichi; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; et al.
JAEA-Conf 2008-005, p.42 - 45, 2008/03
In FY2006, a tandem accelerator was operated for 201days. The maximum voltage was 18 MV and the accelerated ion species was 19 elements (26 nuclides). As the trouble case which occurred previous year, the change of the beam shape occurred often in the injection beam line of the tandem accelerator. The cause was the contact failure of the pole connector of the electrostatics quadrupole lens. Generally, it was difficult to confirm the connection status of the opened pole but we specified a connection abnormal part by the capacitive coupling method. This technique is useful technology which can be applied to the other electrostatics optics elements. Because the charging electric current flowed only about usual about 60% and the terminal voltage became unstable, we opened a tank and checked the charging system. As a result, a problem was confirmed to the damaging of resistance and the installation of the cable. In the seminar, the operation, maintenance and the accelerator development of the tandem accelerator in FY2006 are described.
Matsuda, Makoto; Takeuchi, Suehiro; Tsukihashi, Yoshihiro; Hanashima, Susumu; Abe, Shinichi; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; et al.
Dai-19-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.9 - 12, 2007/01
no abstracts in English
Aono, Tetsuya; Kondo, Masaaki; Sekita, Kenji; Emori, Koichi; Kuroha, Misao; Ouchi, Hiroshi
JAEA-Testing 2006-004, 39 Pages, 2006/06
JAEA-Testing-2006-004.pdf:9.88MB
The High Temperature Engineering Test Reactor (HTTR) has an emergency air purification system(EAPS). The system keeps the service area negative pressure condition and exhausts the filtered air to prevent fission products release to environment in accident condition. The EAPS is one of the engineered safety features which is started automatically when radioactivity in the service area increase or might increase. The performance of the EAPS should satisfy the analytical condition for public dose evaluation in the severest accidents of the HTTR. The performance should be confirmed by function tests. The function tests are divided into many tests corresponding to each assumed phenomenon. The confirmation of the performance of the system was carried out effectively by the tests. Moreover, the stable operation of the system can be achieved by improvements of the method of leak tight tests of exhaust filter unit. The report describes the outline of EAPS system, maintenance works and improvement of the system.
Matsuda, Makoto; Takeuchi, Suehiro; Tsukihashi, Yoshihiro; Hanashima, Susumu; Abe, Shinichi; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; et al.
Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan, p.275 - 277, 2006/00
no abstracts in English
Matsuda, Makoto; Takeuchi, Suehiro; Tsukihashi, Yoshihiro; Horie, Katsuzo*; Ouchi, Isao*; Hanashima, Susumu; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; et al.
Dai-18-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.11 - 14, 2005/11
no abstracts in English
Matsuda, Makoto; Takeuchi, Suehiro; Tsukihashi, Yoshihiro; Horie, Katsuzo; Ouchi, Isao; Hanashima, Susumu; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; et al.
Dai-17-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.1 - 4, 2004/00
no abstracts in English
Yoshida, Tadashi; Kanda, Susumu; Takeuchi, Suehiro; Horie, Katsuzo; Ouchi, Isao; Tsukihashi, Yoshihiro; Hanashima, Susumu; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; et al.
Dai-15-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.51 - 53, 2003/03
no abstracts in English
Matsuda, Makoto; Fujii, Yoshio*; Tayama, Hidekazu; Ishizaki, Nobuhiro; Abe, Shinichi; Hanashima, Susumu; Tsukihashi, Yoshihiro; Horie, Katsuzo; Ouchi, Isao; Kanda, Susumu; et al.
JNC TN7200 2001-001, p.166 - 168, 2002/01
no abstracts in English
Yoshida, Tadashi; Kanda, Susumu; Takeuchi, Suehiro; Hanashima, Susumu; Ouchi, Isao; Horie, Katsuzo; Tsukihashi, Yoshihiro; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; et al.
JAERI-Conf 2000-019, p.30 - 32, 2001/02
no abstracts in English
Takeuchi, Suehiro; Abe, Shinichi; Hanashima, Susumu; Horie, Katsuzo; Ishizaki, Nobuhiro; Kanda, Susumu; Matsuda, Makoto; Ouchi, Isao; Tayama, Hidekazu; Tsukihashi, Yoshihiro; et al.
Proc. of 8th Int. Conf. on Heavy Ion Accelerator Technology, p.152 - 167, 1998/00
no abstracts in English
Takeuchi, Suehiro; Matsuda, Makoto; Ishizaki, Nobuhiro; Tayama, Hidekazu; Ouchi, Isao;
Proceedings of 23rd Linear Accelerator Meeting in Japan, p.121 - 123, 1998/00
no abstracts in English
; ; Kanazawa, Shuhei; ; Ouchi, Isao;
Dai-9-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, 0, p.42 - 44, 1996/00
no abstracts in English
; ; ; Hanashima, Susumu; ; Ouchi, Isao; Horie, Katsuzo; Tsukihashi, Yoshihiro; Abe, Shinichi; Kanazawa, Shuhei; et al.
Dai-9-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, 0, p.22 - 25, 1996/00
no abstracts in English
