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Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.
Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12
Times Cited Count：6 Percentile：51.19(Geosciences, Multidisciplinary)The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.
H monitoring in radioactive gaseous wasteFurutani, Misa; Kometani, Tatsunari; Nakagawa, Masahiro; Ueno, Yumi; Sato, Junya; Iwai, Yasunori*
Hoken Butsuri (Internet), 55(2), p.97 - 101, 2020/06
Herein, an oxidation catalyst was introduced after heating it to 600
C to oxidize tritium gas (HT) existing in exhaust into tritiated water vapor (HTO). This study aims to establish a safer H monitoring system by lowering the heating temperature required for the catalyst. In these experiments, which were conducted in the Nuclear Science Research Institute, Japan Atomic Energy Agency, cupric oxide, hydrophobic palladium/silicon dioxide (Pd/SiO
), and platinum/aluminum oxide (Pt/AlO
) catalysts were ventilated using standard hydrogen gas. After comparing the oxidation efficiency of each catalyst at different temperatures, we found that the hydrophobic Pd/SiO and Pt/AlO catalysts could oxidize HT into HTO at 25C.
C monitoring in gaseous radioactive wasteUeno, Yumi; Nakagawa, Masahiro; Sato, Junya; Iwai, Yasunori
Hoken Butsuri, 51(1), p.7 - 11, 2016/03
In the Nuclear Science Research Institute, Japan Atomic Energy Agency (JAEA), in order to oxidize C, which exists in various chemical forms in exhaust, into CO, a copper oxide (CuO) catalyst is introduced after heating to 600C. Our goal was to establish a safer C monitoring system by lowering the heating temperature required for the catalyst; therefore, we developed a new hydrophobic palladium/silicon dioxide (Pd/SiO) catalyst that makes the carrier's surface hydrophobic. In these experiments, catalysts CuO, platinum/aluminum oxide (Pt/AlO), palladium/zirconium dioxide (Pd/ZrO), hydrophobic Pd/SiO, and hydrophilic Pd/SiO were ventilated with standard methane gas, and we compared the oxidation efficiency of each catalyst at different temperatures. As a result, we determined that the hydrophobic Pd/SiO catalyst had the best oxidation efficiency. By substituting the currently used CuO catalyst with the hydrophobic Pd/SiO catalyst, we will be able to lower the working temperature from 600C to 300C and improve the safety of the monitoring process.
C discharge at RI facilities; A Comparison of collection and oxidation methodsUeno, Yumi; Koarashi, Jun; Iwai, Yasunori; Sato, Junya; Takahashi, Teruhiko; Sawahata, Katsunori; Sekita, Tsutomu; Kobayashi, Makoto; Tsunoda, Masahiko; Kikuchi, Masamitsu
Hoken Butsuri, 49(1), p.39 - 44, 2014/03
The Japan Atomic Energy Agency has conducted a monthly monitoring of airborne C discharge at the forth research building (RI facility) of the Tokai Research and Development Center. In the current monitoring, C, which exists in various chemical forms in airborne effluent, is converted into CO with CuO catalyst and then collected using monoethanolamine (MEA) as CO absorbent. However, this collection method has some issues on safety management because the CuO catalyst requires a high heating temperature (600C) to ensure a high oxidation efficiency and the MEA is specified as a poisonous and deleterious substance. To establish a safer, manageable and reliable method for monitoring airborne C discharge, we examined collection methods that use different CO absorbents (MEA and Carbo-Sorb E) and oxidation catalysts (CuO, Pt/Alumina and Pd/ZrO). The results showed 100% CO collection efficiency of MEA during a 30-day sampling period under the condition tested. In contrast, Carbo-Sorb E was found to be unsuitable for the monthly-long CO collection because of its high volatile nature. Among the oxidation catalysts, the Pd/ZrO showed the highest oxidation efficiency for CH
at a lower temperature.
Yamada, Katsunori; Fujii, Katsutoshi; Kanda, Hiroshi; Higashi, Daisuke; Kobayashi, Toshiaki; Nakagawa, Masahiro; Fukami, Tomoyo; Yoshida, Keisuke; Ueno, Yumi; Nakajima, Junya; et al.
JAEA-Review 2013-033, 51 Pages, 2013/12
JAEA-Review-2013-033.pdf:2.73MB
After the accident at Fukushima Dai-ichi Nuclear Power Plant, various numerical criteria relevant to radiation protection were defined. We surveyed these criteria through internet. As a result of survey, the following 13 items were identified: (1) criteria for taking stable iodine tablets, (2) criteria for the screening of surface contamination, (3) evacuation area, sheltering area, etc., (4) activity concentrations in food, drinking water, etc., (5) dose limit for radiation workers engaged in emergency work, (6) guideline levels of radioactive substances in bathing areas, (7) criteria for use of school buildings and schoolyards, (8) restriction on planting rice, (9) acceptable activity concentrations in feedstuff, (10) acceptable activity concentrations in compost, (11) criteria for export containers and ships, (12) criteria for contaminated waste, (13) standards for radiation workers engaged in decontamination work. In this report, the basis of and issues on these criteria are summarized.
C monitoring in RI facilitiesUeno, Yumi; Takahashi, Teruhiko; Sawahata, Katsunori; Kikuchi, Masamitsu; Tsunoda, Masahiko
no journal, ,
no abstracts in English
Ozawa, Mayumi; Yabuki, Koshi; Shimada, Asako; Ueno, Takashi
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no abstracts in English
He in radioactive gaseous wasteKometani, Tatsunari; Furutani, Misa; Nakagawa, Masahiro; Ueno, Yumi; Sato, Junya
no journal, ,
no abstracts in English
C monitoring in gaseous radioactive waste in reprocessing plant and RI using facilitiesUeno, Yumi; Nakagawa, Masahiro; Sato, Junya; Iwai, Yasunori
no journal, ,
no abstracts in English
