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Yokoyama, Sumi*; Tatsuzaki, Hideo*; Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Hirao, Shigekazu*; Aoki, Katsunori; Tachiki, Shuichi*; Ezaki, Iwao*; Hoshi, Katsuya; Tsujimura, Norio
Journal of Radiological Protection, 42(3), p.031504_1 - 031504_17, 2022/09
Times Cited Count：1 Percentile：31.61(Environmental Sciences)In Japan, the radiation-dose limit for the lens of the eye was revised in April 2021. Consequently, for workers, the numerical values of the equivalent dose to the lens of the eye are equal to those of the effective dose. Radiation workers, radiation safety officers and licensees must comply with regulations related to radiation protection and optimize protection. The new guidelines on dose monitoring of the lens of the eye developed by the Japan Health Physics Society recommend for the dose to be estimated near the eye for accurate estimation, when the dose to the lens approaches or exceeds the management criteria. However, there is limited information regarding the non-uniform exposure of nuclear power plant workers. In this study, the dose equivalents of high-dose-rate workplaces and the personal doses of 88 workers were estimated at four Japanese commercial nuclear power plant sites (RWR: 3 units and BWR: 3 units) and the dose to the lens of the eye and the exposure situations of the workers were analyzed.
Yokoyama, Sumi*; Ezaki, Iwao*; Tatsuzaki, Hideo*; Tachiki, Shuichi*; Hirao, Shigekazu*; Aoki, Katsunori; Tanimura, Yoshihiko; Hoshi, Katsuya; Yoshitomi, Hiroshi; Tsujimura, Norio
Radiation Measurements, 138, p.106399_1 - 106399_5, 2020/11
Times Cited Count：2 Percentile：24.28(Nuclear Science & Technology)Yamanishi, Toshihiko; Hayashi, Takumi; Shu, Wataru; Kawamura, Yoshinori; Nakamura, Hirofumi; Iwai, Yasunori; Kobayashi, Kazuhiro; Isobe, Kanetsugu; Arita, Tadaaki; Hoshi, Shuichi; et al.
Fusion Engineering and Design, 83(10-12), p.1359 - 1363, 2008/12
Times Cited Count：4 Percentile：29.49(Nuclear Science & Technology)At TPL (Tritium Process Laboratory) of JAEA, ITER relevant tritium technologies have been studied. The design studies of Air Detritiation System have been carried out in JAEA as a contribution of Japan to ITER. For the tritium processing technologies, our efforts have been focused on the research of the tritium recovery system of ITER test blanket system. A ceramic proton conductor has been studied as an advanced blanket system. A series of fundamental studies on tritium safety technologies not only for ITER but also for fusion DEMO plants has also been carried out at TPL of JAEA. The main research activities in this field are the tritium behavior in a confinement and its barrier materials; monitoring; accountancy; detritiation and decontamination etc. In this paper, the results of above recent activities at TPL of JAEA are summarized from viewpoint of ITER relevant and future fusion DEMO reactors.
Yamanishi, Toshihiko; Yamada, Masayuki; Suzuki, Takumi; Shu, Wataru; Kawamura, Yoshinori; Nakamura, Hirofumi; Iwai, Yasunori; Kobayashi, Kazuhiro; Isobe, Kanetsugu; Hoshi, Shuichi; et al.
Fusion Science and Technology, 54(1), p.315 - 318, 2008/07
Times Cited Count：11 Percentile：59.16(Nuclear Science & Technology)The construction of the building and safety systems of the TPL was completed until 1985. The operations of the safety systems with tritium have been started from March 1988. The amount of tritium held at the TPL was 13 PBq at March 2007. The average tritium concentration in a stream from a stack of the TPL to environment was 6.0
10
Bq/cm
; and is 1/100 smaller than that of the regulation value for the concentration of HTO in the air in Japan. The safety operation results with tritium have thus been obtained. A set of failure data of several main components of the TPL was also obtained as the valuable data for fusion tritium facilities.
Hayashi, Takumi; Isobe, Kanetsugu; Kobayashi, Kazuhiro; Iwai, Yasunori; Kawamura, Yoshinori; Nakamura, Hirofumi; Shu, Wataru; Arita, Tadaaki; Hoshi, Shuichi; Suzuki, Takumi; et al.
Fusion Science and Technology, 52(3), p.651 - 658, 2007/10
Times Cited Count：2 Percentile：18.73(Nuclear Science & Technology)The design studies of Air Detirtiation System have been carried out in JAEA as a contribution of Japan to ITER. For the tritium processing technologies, our efforts have been focused on the R&D of the tritium recovery system of ITER test blanket, using mainly molecular sieve and/or electro-chemical pumping system. A series of fundamental studies on tritium safety technologies, such as tritium behavior in a confinement and its barrier materials, monitoring, accountancy, detritiation and decontamination etc., has been carried out as a major activity in JAEA for ITER and fusion demo reactors. In this paper, the above recent activities on tritium technologies at Tritium Process Lab. in JAEA are summarized for ITER and future fusion reactor.
Kobayashi, Kazuhiro; Miura, Hidenori*; Hayashi, Takumi; Hoshi, Shuichi; Yamanishi, Toshihiko
Fusion Science and Technology, 52(3), p.711 - 715, 2007/10
Times Cited Count：3 Percentile：25.51(Nuclear Science & Technology)The tritium released in the building is removed by Atmosphere Detritiation System (ADS), where the tritium is oxidized by catalysts and is removed as water. Special gas of SF is used as an electric insulation gas in ITER, and is expected to be released in an accident such as fire. Although SF has the potential as a catalyst poison, the performance of ADS with the existence of SF has not been confirmed yet. Therefore, to study the effect of SF, the performance tests of ADS was carried out with air containing 
1% of hydrogen, 1% of methane and 1% of SF. The SF gas was notably decomposed in the case of the catalyst temperature higher than 673 K. In addition, a part of the water produced by the 473 K catalyst was reduced to hydrogen due to the reaction with the decomposed gas in SF. Consequently, the detritiation factor of ADS was decreased to less than 50 from 
1000 of its initial value.
Yokoyama, Sumi*; Ezaki, Iwao*; Aoki, Katsunori; Tatsuzaki, Hideo*; Hirao, Shigekazu*; Tachiki, Shuichi*; Yoshitomi, Hiroshi; Hoshi, Katsuya; Tanimura, Yoshihiko; Oguchi, Hiroyuki*; et al.
no journal, ,
no abstracts in English
Ezaki, Iwao*; Aoki, Katsunori; Tatsuzaki, Hideo*; Tachiki, Shuichi*; Hirao, Shigekazu*; Yoshitomi, Hiroshi; Hoshi, Katsuya; Tanimura, Yoshihiko; Oguchi, Hiroyuki*; Tsujimura, Norio; et al.
no journal, ,
no abstracts in English
