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Hamamoto, Shimpei; Ishitsuka, Etsuo; Nakagawa, Shigeaki; Goto, Minoru; Matsuura, Hideaki*; Katayama, Kazunari*; Otsuka, Teppei*; Tobita, Kenji*
Proceedings of 2021 International Congress on Advances in Nuclear Power Plants (ICAPP 2021) (USB Flash Drive), 5 Pages, 2021/10
Impurity concentrations of hydrogen and hydride in the coolant were investigated in detail for the HTTR, a block type high-temperature gas reactor owned by Japan. As a result, it was found that CH
was 1/10 of H
concentration, which was under the conventional detection limit. If the ratio of H to CH in the coolant is the same as the ratio of HT to CH
T, the CHT has a larger dose conversion factor, and this compositional ratio is an important finding for the optimal dose evaluation. Further investigation of the origin of CH suggested that CH was produced as a result of a thermal equilibrium reaction rather than being released as an impurity from the core.
Dipu, A. L.; Ohashi, Hirofumi; Hamamoto, Shimpei; Sato, Hiroyuki; Nishihara, Tetsuo
Annals of Nuclear Energy, 88, p.126 - 134, 2016/02
Times Cited Count：6 Percentile：45.92(Nuclear Science & Technology)The tritium concentration in the high temperature engineering test reactor (HTTR) was measured during the high temperature continuous operation for 50 days. The tritium concentration in the primary helium gas increased after startup and reached a maximum value. It then decreased slightly over the course during the normal operation phase. Decrease of concentration of tritium in primary helium gas during the normal operation phase could be attributed to the effect of tritium chemisorption on graphite. The tritium concentration in the secondary helium gas showed a peak value during the power ramp up phase. Afterwards, it decreased gradually at the end of normal power operation. It was assessed that the concentration and total quantity of tritium in the secondary helium cooling system for the HTTR-Iodine Sulfur (IS) system can be maintained below the regulatory limits, which means the hydrogen production plant can be exempt from the safety function of the nuclear facility.
Kawamoto, Yasuko*; Nakaya, Hiroyuki*; Matsuura, Hideaki*; Katayama, Kazunari*; Goto, Minoru; Nakagawa, Shigeaki
Fusion Science and Technology, 68(2), p.397 - 401, 2015/09
Times Cited Count：1 Percentile：8.93(Nuclear Science & Technology)To start up a fusion reactor, it is necessary to provide a sufficient amount of tritium from an external device. Herein, methods for supplying a fusion reactor with tritium are discussed. Use of a high temperature gas cooled reactor (HTGR) as a tritium production device has been proposed. So far, the analyses have been focused only on the operation in which fuel is periodically exchanged (batch) using the block type HTGR. In the pebble bed type HTGR, it is possible to design an operation that has no time loss for refueling. The pebble bed type HTGR (PBMR) and the block type HTGR (GTHTR300) are assumed as the calculation and comparison targets. Simulation is made using the continuous-energy Monte Carlo transport code MVPBURN. It is shown that the continuous operation using the pebble bed type HTGR has almost the same tritium productivity compared with the batch operation using the block type HGTR. The issues for pebble bed type HTGR as a tritium production device are discussed.
Verzilov, Y. M.; Sato, Satoshi; Ochiai, Kentaro; Wada, Masayuki*; Klix, A.*; Nishitani, Takeo
Fusion Engineering and Design, 82(1), p.1 - 9, 2007/01
Times Cited Count：10 Percentile：57.01(Nuclear Science & Technology)no abstracts in English
C operation of the HTTRSakaba, Nariaki; Ohashi, Hirofumi; Takeda, Tetsuaki
Journal of Nuclear Materials, 353(1-2), p.42 - 51, 2006/07
Times Cited Count：11 Percentile：59.17(Materials Science, Multidisciplinary)The permeation of hydrogen isotopes through the Hastelloy XR high-temperature alloy adopted for the heat transfer pipes of the intermediate heat exchanger in the HTTR, is one of the concerns in the hydrogen production system, which will be connected to the HTTR in the near future. The hydrogen permeation between the primary and secondary coolant through the Hastelloy XR was evaluated using the actual hydrogen concentration observed during the initial 950C operation of the HTTR. The hydrogen permeability of the Hastelloy XR was estimated conservatively high as follows. The activation energy E
and pre-exponential factor F of the permeability of hydrogen were E = 65.8 kJ/mol and F = 7.8
10
m
(STP)/(m
sPa
), respectively, in the temperature range from 707K to 900K.
Verzilov, Y. M.; Ochiai, Kentaro; Nishitani, Takeo
Fusion Science and Technology, 48(1), p.650 - 653, 2005/07
Times Cited Count：7 Percentile：44.05(Nuclear Science & Technology)no abstracts in English
C operation of the HTTRSakaba, Nariaki; Matsuzawa, Takaharu*; Hirayama, Yoshiaki*; Nakagawa, Shigeaki; Nishihara, Tetsuo; Takeda, Tetsuaki
Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 8 Pages, 2005/05
The permeation of hydrogen isotopes through the Hastelloy XR high-temperature alloy adopted for the heat exchanger pipes of the intermediate heat exchanger in the HTTR (High Temperature Engineering Test Reactor) is one of the concerns in the hydrogen production system, which will be connected to the HTTR in the near future. An evaluation of the hydrogen permeation between the primary and secondary coolant through the Hastelloy XR was performed using the hydrogen concentration data observed during the initial 950C operation of the HTTR. The hydrogen permeability of the Hastelloy XR was estimated conservatively high as follows. The activation energy E and pre-exponential factor F of the permeability of hydrogen were E = 62 kJ/mol and F = 3.610
cm(NTP)/(cm s Pa), respectively, in the temperature range from 735K to 940K. The results implied that some oxidized film had been formed on the surface of the heat exchanger pipes of the intermediate heat exchanger.
Verzilov, Y. M.; Sato, Satoshi; Nakao, Makoto*; Ochiai, Kentaro; Wada, Masayuki*; Nishitani, Takeo
JAERI-Research 2004-015, 55 Pages, 2004/10
JAERI-Research-2004-015.pdf:3.29MB
no abstracts in English
Takeda, Tetsuaki; Iwatsuki, Jin*
Nuclear Technology, 146(1), p.83 - 95, 2004/04
Times Cited Count：14 Percentile：65.14(Nuclear Science & Technology)The objective of this study is to investigate the effect of the existence of hydrogen in a pipe outside on the amount of permeated deuterium through the pipe. It was found that the amount of permeated deuterium decreases with increasing the partial pressure of hydrogen in the pipe outside when the partial pressure of deuterium in the pipe is lower than 100 Pa and that of hydrogen in the pipe outside is higher than 10 kPa. The amount of permeated deuterium on counter permeation was predicted quantitatively by using an effectiveness factor for diffusivity of deuterium in metals and by taking into account the equilibrium state for hydrogen, deuterium and HD molecules on the metal surface. From the results obtained in this study, it is supposed that the amount of tritium transferred from the primary circuit of the HTTR to the hydrogen production system will be reduced by the existence of high-pressure hydrogen in the catalyst pipe of the steam reformer.
Nishihara, Tetsuo; Hada, Kazuhiko
Nihon Genshiryoku Gakkai-Shi, 41(5), p.571 - 578, 1999/05
Times Cited Count：5 Percentile：40.11(Nuclear Science & Technology)no abstracts in English
Yamashita, Kiyonobu; Sawa, Kazuhiro; Ando, Hiroei; ;
Nihon Genshiryoku Gakkai-Shi, 40(1), p.65 - 69, 1998/00
Times Cited Count：6 Percentile：48.67(Nuclear Science & Technology)no abstracts in English
Verzilov, Y.*; Maekawa, Fujio; Oyama, Yukio
Journal of Nuclear Science and Technology, 33(5), p.390 - 395, 1996/05
Times Cited Count：17 Percentile：78.67(Nuclear Science & Technology)no abstracts in English
Konno, Chikara; Oyama, Yukio; Maekawa, Fujio; Ikeda, Yujiro; Kosako, Kazuaki*; Maekawa, Hiroshi; M.A.Abdou*; Bennett, E. F.*; A.Kumar*; M.Z.Youssef*
Fusion Technology, 28(2), p.347 - 365, 1995/09
no abstracts in English
Konno, Chikara; Oyama, Yukio; Ikeda, Yujiro; ; ; Kosako, Kazuaki*; Maekawa, Hiroshi; Nakagawa, Masayuki; Mori, Takamasa; Nakamura, Tomoo; et al.
Fusion Technology, 28(2), p.273 - 295, 1995/09
no abstracts in English
Maekawa, Hiroshi; M.A.Abdou*; Oyama, Yukio; Konno, Chikara; Maekawa, Fujio; Ikeda, Yujiro; Kosako, Kazuaki*; Nakamura, Tomoo; M.Z.Youssef*; A.Kumar*; et al.
Fusion Technology, 28(2), p.296 - 304, 1995/09
no abstracts in English
Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; ; ; Kosako, Kazuaki*; Maekawa, Hiroshi; Nakagawa, Masayuki; Mori, Takamasa; Nakamura, Tomoo; et al.
Fusion Technology, 28(1), p.216 - 235, 1995/08
no abstracts in English
Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; Maekawa, Fujio; Maekawa, Hiroshi; ; ; Nakamura, Tomoo; M.A.Abdou*; Bennett, E. F.*; et al.
Fusion Technology, 28(1), p.56 - 73, 1995/08
no abstracts in English
Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; Maekawa, Fujio; Maekawa, Hiroshi; ; ; Nakamura, Tomoo; M.A.Abdou*; Bennett, E. F.*; et al.
Fusion Engineering and Design, 28, p.716 - 723, 1995/00
Times Cited Count：5 Percentile：49.26(Nuclear Science & Technology)no abstracts in English
Maekawa, Hiroshi; Maekawa, Fujio; Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; ;
Fusion Technology, 26, p.1086 - 1091, 1994/11
no abstracts in English
Oyama, Yukio; ; Maekawa, Hiroshi
Fusion Technology, 26, p.1098 - 1102, 1994/11
no abstracts in English
