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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.
Kawasaki, Masatsugu; Nakajima, Junya; Yoshida, Keisuke; Kato, Saori; Nishino, Sho; Nozaki, Teo; Nakagawa, Masahiro; Tsunoda, Junichi; Sugaya, Yuki; Hasegawa, Rie; et al.
JAEA-Data/Code 2017-004, 57 Pages, 2017/03
JAEA-Data-Code-2017-004.pdf:2.34MB
In emergency situation of nuclear facilities, we need to estimate the radiation dose due to radiation and radioactivity to grasp the influence range of the accident in the early stage. Therefore, we prepare the case studies of dose assessment for public exposure dose and personal exposure dose and contribute them to emergency procedures. This document covers about accidents of nuclear facilities in Nuclear Science Research Institute and past accident of nuclear power plant, and it can be used for inheritance of techniques of emergency dose assessment.
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.
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.
Nakagawa, Masahiro; Nojima, Shun; Fujii, Katsutoshi; Shishido, Nobuhito; Sakai, Toshiya; Umehara, Takashi; Shimizu, Isamu
Hoken Butsuri, 47(3), p.189 - 193, 2012/10
It is essential to wear an air-purifying respirator in the radiation works in a contaminated atmosphere. A breath-responsive-powered air-purifying respirator (BR-PAPR) has been recently developed. However, no research has yet been conducted to determine the protection factor (PF) of the BR-PAPR in actual workplaces. In this study, the PFs of the BR-PAPR were measured by a man-test apparatus and compared with those of a non-powered full face mask. The PFs were measured under three different situations; normal wearing condition, clogging the filter and leaving a gap between the face and the mask. Under these situations, it was found that the PFs of the BR-PAPR are higher than those of the non-powered full face mask. PFs greater than 4000 were obtained for 95% of the subjects who wear the BR-PAPR, and PFs over 6667, the upper limit of the man-test apparatus, were obtained for 49% of them. The questionnaire survey was conducted for workers. The results showed that the workers feel a reduced burden when they wear the BR-PAPR. The results of this study showed high protection performance and operation efficiency of the BR-PAPR.
Saeki, Kazutoshi*; Nakagawa, Kei*; Wada, Shinichiro*; Shibata, Masahiro; Horoshiro, Yoshinari*; Jinno, Kenji*
Nendo Kagaku, 42(1), p.1 - 5, 2002/08
None
C-carbon fiber composite ceramics as plasma facing materials in nuclear fusion reactor, part 3; Heat resistance evaluation by electron beam irradiation and by in situ plasma discharge in JT-60*; Saido, Masahiro; Nakamura, Kazuyuki; Akiba, Masato; ; Dairaku, Masayuki; *; *; *; Goto, Yoshitaka*
Nihon Seramikkusu Kyokai Gakujutsu Rombunshi, 105(1228), p.1091 - 1098, 1997/12
Times Cited Count：1 Percentile：18.67(Materials Science, Ceramics)no abstracts in English
C-carbon fiber composite ceramics as plasma facing materials in nuclear fusion reactor, 3; Heat resistance evaluation by electron beam irradiation and by in situ plasma discharge in JT-60Jimbo, Ryutaro*; Saido, Masahiro; Nakamura, Kazuyuki; Akiba, Masato; ; Dairaku, Masayuki; *; *; *; *
Journal of the Ceramic Society of Japan, International Edition, 105, p.1179 - 1187, 1997/00
no abstracts in English
*; Saido, Masahiro; Nakamura, Kazuyuki; Akiba, Masato; ; Goto, Yoshitaka*; *; *; Yamaki, Takahiro*; *; et al.
Journal of Nuclear Materials, 233-237(PT.A), p.781 - 786, 1996/00
Times Cited Count：13 Percentile：72.4(Materials Science, Multidisciplinary)no abstracts in English
Nakagawa, Masahiro; Nojima, Shun; Fujii, Katsutoshi; Shishido, Nobuhito; Sakai, Toshiya; Umehara, Takashi; Shimizu, Isamu
no journal, ,
no abstracts in English
Nakagawa, Masahiro; Kato, Takuya; Nojima, Shun; Sakai, Toshiya; Shishido, Nobuhito; Umehara, Takashi
no journal, ,
Mask fitting tester "MT-03" is widespread as educational equipment in medical institution and industrial organization. However, there are few examples introduced in order to check the protection performance of purifying respirators in nuclear facilities. In this study, we compared protection factors obtained by MT-03 and those obtained by Mask-man test apparatus "MT-100N". As a result, although the change of measurement result is larger and measured value is higher than that of MT-100N, it was found that protection performance can be checked appropriately.
Nojima, Shun; Sakai, Jun; Nakagawa, Masahiro; Shirato, Yoshihiro; Aoyagi, Hiroyuki; Otsuka, Yoshikazu; Sakai, Toshiya; Shishido, Nobuhito; Umehara, Takashi
no journal, ,
no abstracts in English
Furutani, Misa; Aoyagi, Hiroyuki*; Shirato, Yoshihiro; Nojima, Shun; Nakagawa, Masahiro; Otsuka, Yoshikazu; Niinuma, Shinichi*; Sakai, Toshiya; Muto, Yasushi; Nanri, Tomohiro; et al.
no journal, ,
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
