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Mori, Yuichiro*; Kagi, Hiroyuki*; Aoki, Katsutoshi*; Takano, Masahiro*; Kakizawa, Sho*; Sano, Asami; Funakoshi, Kenichi*
Earth and Planetary Science Letters, 634, p.118673_1 - 118673_8, 2024/05
To investigate silicon effects on the hydrogen-induced volume expansion of iron, neutron diffraction and X-ray diffraction experiments were conducted to examine hcp-Fe
Si
under high pressures and high temperatures. Neutron diffraction experiments were performed on the deuterated hcp-FeSi at 13.5 GPa and 900 K, and at 12.1 GPa and 300 K. By combining the P-V-T equation of state of hcp-FeSi, present results indicate that the hydrogen-induced volume expansion of hcp-FeSi is 10% greater than that of pure hcp iron. Using the obtained values, we estimated the hydrogen content that would reproduce the density deficit in the inner core, which was 50% less than that without the effect of silicon. Possible hydrogen content, 
, in the inner core and the outer core was calculated to be 0.07 and 0.12-0.15, respectively, when reproducing the density deficit of the inner core with hcp-FeSiHx.
O/HO vapor generator for contrast-variation neutron scatteringArima-Osonoi, Hiroshi*; Takata, Shinichi; Kasai, Satoshi*; Ouchi, Keiichi*; Morikawa, Toshiaki*; Miyata, Noboru*; Miyazaki, Tsukasa*; Aoki, Hiroyuki; Iwase, Hiroki*; Hiroi, Kosuke; et al.
Journal of Applied Crystallography, 56(6), p.1802 - 1812, 2023/12
Times Cited Count：0 Percentile：0.02(Chemistry, Multidisciplinary)Sujita, Ryota*; Imai, Sahori*; Ouchi, Makoto*; Aoki, Hiroyuki; Terashima, Takaya*
Macromolecules, 56(23), p.9738 - 9749, 2023/12
Times Cited Count：0 Percentile：0(Polymer Science)Hashimoto, Kei*; Shiwaku, Toru*; Aoki, Hiroyuki; Yokoyama, Hideaki*; Mayumi, Koichi*; Ito, Kozo*
Science Advances (Internet), 9(47), p.eadi8505_1 - eadi8505_8, 2023/11
Times Cited Count：1 Percentile：52.07(Multidisciplinary Sciences)Ishii, Katsunori; Morita, Keisuke; Noguchi, Hiroki; Aoki, Takeshi; Mizuta, Naoki; Hasegawa, Takeshi; Nagatsuka, Kentaro; Nomoto, Yasunobu; Shimizu, Atsushi; Iigaki, Kazuhiko; et al.
Dai-27-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 4 Pages, 2023/09
Liu, Y.*; Miyata, Noboru*; Miyazaki, Tsukasa*; Shundo, Atsuomi*; Kawaguchi, Daisuke*; Tanaka, Keiji*; Aoki, Hiroyuki
Langmuir, 39(29), p.10154 - 10162, 2023/06
Times Cited Count：1 Percentile：52.07(Chemistry, Multidisciplinary)Ishii, Katsunori; Aoki, Takeshi; Isaka, Kazuyoshi; Noguchi, Hiroki; Shimizu, Atsushi; Sato, Hiroyuki
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 9 Pages, 2023/05
Aoki, Takeshi; Shimizu, Atsushi; Noguchi, Hiroki; Kurahayashi, Kaoru; Yasuda, Takanori; Nomoto, Yasunobu; Iigaki, Kazuhiko; Sato, Hiroyuki; Sakaba, Nariaki
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 9 Pages, 2023/05
The safety design philosophy is developed for the HTTR (High Temperature Engineering Test Reactor) heat application test facility connecting high temperature gas-cooled reactor (HTGR) and the hydrogen production plant. The philosophy was proposed to apply proven conventional chemical plant standards to the hydrogen production facility for ensuring public safety against anticipated disasters caused by high pressure and combustible gases. The present study also proposed the safety design philosophy to meet specific safety requirements identified to the nuclear facilities with coupling to the hydrogen production facility such as measures to ensure a capability of normal operation of the nuclear facility against a fire and/or explosion of leaked combustible material, and fluctuation of amount of heat removal occurred in the hydrogen production plant. The safety design philosophy will be utilized to establish its basic and detailed designs of the HTTR-heat application test facility.
Nomoto, Yasunobu; Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Okita, Shoichiro; Ishii, Katsunori; Kurahayashi, Kaoru; Yasuda, Takanori; Tanaka, Masato; Isaka, Kazuyoshi; et al.
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 7 Pages, 2023/05
Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Okita, Shoichiro; Ishii, Katsunori; Kurahayashi, Kaoru; Yasuda, Takanori; Tanaka, Masato; Isaka, Kazuyoshi; Noguchi, Hiroki; et al.
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 6 Pages, 2023/05
Ni
D
at high 
conditionsShito, Chikara*; Kagi, Hiroyuki*; Kakizawa, Sho*; Aoki, Katsutoshi*; Komatsu, Kazuki*; Iizuka, Riko*; Abe, Jun*; Saito, Hiroyuki*; Sano, Asami; Hattori, Takanori
American Mineralogist, 108(4), p.659 - 666, 2023/04
Times Cited Count：1 Percentile：64.83(Geochemistry & Geophysics)The phase relation and crystal structure of FeNiH (D) at high pressures and temperatures up to 12 GPa and 1000 K were clarified by in-situ X-ray and neutron diffraction measurements. Under conditions of the present study, no deuterium atoms occupied tetragonal (
) sites of face-centered cubic (fcc) FeNiD unlike fcc FeH(D). The deuterium-induced volume expansion per deuterium 
was determined as 2.45(4) 
and 3.31(6) for fcc and hcp phases, respectively, which were significantly larger than the corresponding values for FeD. The value slightly increased with increasing temperature. This study suggests that only 10% of nickel in iron drastically changes the behaviors of hydrogen in metal. Assuming that is constant regardless of pressure, the maximum hydrogen content in the Earth's inner core is estimated to be one to two times the amount of hydrogen in the oceans.
Hibino, Masayuki*; Takata, Shinichi; Hiroi, Kosuke; Aoki, Hiroyuki; Terashima, Takaya*
Macromolecules, 56(8), p.2955 - 2964, 2023/04
Times Cited Count：0 Percentile：0(Polymer Science)Shimokita, Keisuke*; Yamamoto, Katsuhiro*; Miyata, Noboru*; Nakanishi, Yohei*; Shibata, Motoki*; Takenaka, Mikihito*; Yamada, Norifumi*; Seto, Hideki*; Aoki, Hiroyuki; Miyazaki, Tsukasa*
Soft Matter, 19(11), p.2082 - 2089, 2023/03
Times Cited Count：0 Percentile：0(Chemistry, Physical)Yoshimune, Wataru*; Kikkawa, Nobuaki*; Yoneyama, Hiroaki*; Takahashi, Naoko*; Minami, Saori*; Akimoto, Yusuke*; Mitsuoka, Takuya*; Kawaura, Hiroyuki*; Harada, Masashi*; Yamada, Norifumi*; et al.
ACS Applied Materials & Interfaces, 14(48), p.53744 - 53754, 2022/11
Times Cited Count：6 Percentile：59.75(Nanoscience & Nanotechnology)Shimokita, Keisuke*; Yamamoto, Katsuhiro*; Miyata, Noboru*; Arima-Osonoi, Hiroshi*; Nakanishi, Yohei*; Takenaka, Mikihito*; Shibata, Motoki*; Yamada, Norifumi*; Seto, Hideki*; Aoki, Hiroyuki; et al.
Langmuir, 38(41), p.12457 - 12465, 2022/10
Times Cited Count：0 Percentile：0(Chemistry, Multidisciplinary)Imai, Sahori*; Arakawa, Masato*; Nakanishi, Yohei*; Takenaka, Mikihito*; Aoki, Hiroyuki; Ouchi, Makoto*; Terashima, Takaya*
Macromolecules, 55(20), p.9113 - 9125, 2022/10
Times Cited Count：2 Percentile：27.19(Polymer Science)Yamaguchi, Ko*; Kawaguchi, Daisuke*; Miyata, Noboru*; Miyazaki, Tsukasa*; Aoki, Hiroyuki; Yamamoto, Satoru*; Tanaka, Keiji*
Physical Chemistry Chemical Physics, 24(36), p.21578 - 21582, 2022/09
Times Cited Count：5 Percentile：70.33(Chemistry, Physical)Aoki, Takeshi; Shimizu, Atsushi; Iigaki, Kazuhiko; Okita, Shoichiro; Hasegawa, Takeshi; Mizuta, Naoki; Sato, Hiroyuki; Sakaba, Nariaki
JAEA-Review 2022-016, 193 Pages, 2022/08
JAEA-Review-2022-016.pdf:42.06MB
Aiming to realize a massive, cost-effective and carbon-free hydrogen production technology utilizing a high temperature gas cooled reactor (HTGR), Japan Atomic Energy Agency (JAEA) is planning a HTTR heat application test producing hydrogen with High Temperature Engineering Test Reactor (HTTR) achieved 950
C of the highest reactor outlet coolant temperature in the world. In the HTTR heat application test, it is required to establish its safety design realizing highly safe connection of a HTGR and a hydrogen production plant by the Nuclear Regulation Authority to obtain the permission of changes to reactor installation. However, installation of a system connecting the hydrogen production plant and a nuclear reactor, and its safety design has not been conducted so far in conventional nuclear power plant including HTTR in the world. A special committee on the HTTR heat application test, established under the HTGR Research and Development Center, considered a safety design philosophy for the HTTR heat application test based on an authorized safety design of HTTR in terms of conformity to the New Regulatory Requirements taking into account new considerable events as a result of the plant modification and connection of the hydrogen production plant. This report provides materials of the special committee such as technical reports, comments provided from committee members, response from JAEA for the comments and minutes of the committee.
Aoki, Takeshi; Sato, Hiroyuki
Proceedings of 29th International Conference on Nuclear Engineering (ICONE 29) (Internet), 6 Pages, 2022/08
High temperature gas-cooled reactor (HTGR) has a potential to produce competitive and large amount of carbon-free hydrogen. It is required to establish the control method and system for the HTGR hydrogen production system to maintain its normal operation against the abnormality in the hydrogen production facility through performance evaluations of the control system by transient thermal-hydraulic analysis. In the present study, the reactor response against the disturbance in the reactor inlet coolant temperature was revealed in the HTGR hydrogen production system. The analytical results showed that the reactor outlet coolant control system enabled to control the variation of the reactor outlet coolant temperature was less than 4C against 30C of large disturbance in the reactor inlet coolant temperature and to maintain its normal operation in the HTGR hydrogen production system. Thus, the effectiveness of the control method was confirmed.
Aoki, Takeshi; Shimizu, Atsushi; Iigaki, Kazuhiko; Okita, Shoichiro; Hasegawa, Takeshi; Mizuta, Naoki; Sato, Hiroyuki; Sakaba, Nariaki
JAEA-Technology 2022-011, 60 Pages, 2022/07
JAEA-Technology-2022-011.pdf:2.08MB
Japan Atomic Energy Agency is planning a High Temperature Engineering Test Reactor (HTTR) heat application test producing hydrogen with the HTTR which achieved the highest reactor outlet coolant temperature of 950C in the world to realize a massive, cost-effective and carbon-free hydrogen production technology utilizing a high temperature gas cooled reactor (HTGR). In the HTTR heat application test, it is required to establish its safety design for coupling a hydrogen production plant to HTGR through the licensing by the Nuclear Regulation Authority (NRA). A draft of a safety design philosophy for the HTTR heat application test facility was considered taking into account postulated events due to the plant modification and coupling of the hydrogen production plant based on the HTTR safety design which was authorized through the safety review of the NRA against New Regulatory Requirements. The safety design philosophy was examined to apply proven conventional chemical plant standards to the hydrogen production plant for ensuring public safety against disasters caused by high pressure gases. This report presents a result of a consideration on safety design philosophies regarding the reasonability and condition to apply the High Pressure Gas Safety Act for the hydrogen production plant, safety classifications, seismic design classification, identification of important safety system.
