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Journal Articles

Hydrogenation of silicon-bearing hexagonal close-packed iron and its implications for density deficits in the inner core

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$$_{0.95}$$Si$$_{0.05}$$ under high pressures and high temperatures. Neutron diffraction experiments were performed on the deuterated hcp-Fe$$_{0.95}$$Si$$_{0.05}$$ 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-Fe$$_{0.95}$$Si$$_{0.05}$$, present results indicate that the hydrogen-induced volume expansion of hcp-Fe$$_{0.95}$$Si$$_{0.05}$$ 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, $$x$$, 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-Fe$$_{0.95}$$Si$$_{0.05}$$Hx.

Journal Articles

Optimization in granulation conditions for adsorbent of extraction chromatography

Hasegawa, Kenta; Goto, Ichiro*; Miyazaki, Yasunori; Ambai, Hiromu; Watanabe, So; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki

Mechanical Engineering Journal (Internet), 11(2), p.23-00407_1 - 23-00407_8, 2024/04

Journal Articles

Overview of development program for engineering scale extraction chromatography MA(III) recovery system

Watanabe, So; Takahatake, Yoko; Hasegawa, Kenta; Goto, Ichiro*; Miyazaki, Yasunori; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki

Mechanical Engineering Journal (Internet), 11(2), p.23-00461_1 - 23-00461_10, 2024/04

JAEA Reports

Utilization of gamma ray irradiation at the WASTEF Facility

Sano, Naruto; Yamashita, Naoki; Watanabe, Masaya; Tsukada, Manabu*; Hoshino, Kazutoyo*; Hirai, Koki; Ikegami, Yuta*; Tashiro, Shinsuke; Yoshida, Ryoichiro; Hatakeyama, Yuichi; et al.

JAEA-Technology 2023-029, 36 Pages, 2024/03


At the Waste Safety Testing Facility (WASTEF), the gamma ray irradiation device "Gamma Cell 220" was relocated from the 4th research building of the Nuclear Science Research Institute in FY2019, and the use of gamma ray irradiation has begun. Initially, Fuel Cycle Safety Research Group, Fuel Cycle Safety Research Division, Nuclear Safety Research Center, Sector of Nuclear Safety Research and Emergency Preparedness, the owner of this device, conducted the tests as the main user, but since 2022, other users, including those outside the organization, have started using it. The gamma ray irradiation device "Gamma Cell 220" is manufactured by Nordion International Inc. in Canada. Since it was purchased in 1989, the built-in 60Co radiation source has been updated once, and safety research related to nuclear fuel cycles, etc. It is still used for this purpose to this day. This report summarizes the equipment overview of the gamma ray irradiation device "Gamma Cell 220", its permits and licenses at WASTEF, usage status, maintenance and inspection, and future prospects.

Journal Articles

X-ray free electron laser observation of ultrafast lattice behaviour under femtosecond laser-driven shock compression in iron

Sano, Tomokazu*; Matsuda, Tomoki*; Hirose, Akio*; Terai, Tomoyuki*; Kakeshita, Tomoyuki*; Inubushi, Yuichi*; Sato, Takahiro*; Yabashi, Makina*; Shobu, Takahisa; 22 of others*

Scientific Reports (Internet), 13, p.13796_1 - 13796_10, 2023/08

 Times Cited Count:0 Percentile:0(Multidisciplinary Sciences)

Journal Articles

Kinetic mass transfer behavior of Eu(III) in nitrilotriacetamide-impregnated polymer-coated silica particles

Miyagawa, Akihisa*; Hayashi, Naoki*; Kuzure, Yoshiaki*; Takahashi, Takumi*; Iwamoto, Hibiki*; Arai, Tsuyoshi*; Nagatomo, Shigenori*; Miyazaki, Yasunori; Hasegawa, Kenta; Sano, Yuichi; et al.

Bulletin of the Chemical Society of Japan, 96(7), p.671 - 676, 2023/07

 Times Cited Count:3 Percentile:65.78(Chemistry, Multidisciplinary)

We investigated the distribution mechanism of Eu(III) in a single polymer-coated silica particle including nitrilotriacetamide (NTA) extractants known as HONTA and TOD2EHNTA. The present study provides a valuable approach for the evaluation and enhancement of the functionality of "single extractant-impregnated polymer-coated silica particle".

Journal Articles

Development of engineering scale extraction chromatography separation system, 1; Overview of developments in engineering scale system

Watanabe, So; Takahatake, Yoko; Hasegawa, Kenta; Goto, Ichiro*; Miyazaki, Yasunori; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 6 Pages, 2023/05

Journal Articles

Development of engineering scale extraction chromatography separation system, 2; Spray drying granulation of silica support for adsorbent

Hasegawa, Kenta; Goto, Ichiro*; Miyazaki, Yasunori; Ambai, Hiromu; Watanabe, So; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 5 Pages, 2023/05

Journal Articles

Design of MA(III)/Ln(III) separation process of extraction chromatography technology

Akuzawa, Tadashi*; Kim, S.-Y.*; Kubota, Masahiko*; Wu, H.*; Watanabe, So; Sano, Yuichi; Takeuchi, Masayuki; Arai, Tsuyoshi*

Journal of Radioanalytical and Nuclear Chemistry, 331(12), p.5851 - 5858, 2022/12

 Times Cited Count:5 Percentile:66.21(Chemistry, Analytical)

Journal Articles

Kinetics and mechanism of Eu(III) transfer in tributyl phosphate microdroplet/HNO$$_{3}$$ aqueous solution system revealed by fluorescence microspectroscopy

Miyagawa, Akihisa*; Kusano, Yuka*; Nagatomo, Shigenori*; Sano, Yuichi; Nakatani, Kiyoharu*

Analytical Sciences, 38(7), p.955 - 961, 2022/07

 Times Cited Count:0 Percentile:0(Chemistry, Analytical)

In this study, we reveal an Eu(III) extraction mechanism at the interface between HNO$$_{3}$$ and tributyl phosphate (TBP) solutions using fluorescence microspectroscopy. The mass transfer rate constant at the interface is obtained from the analysis of fluorescence intensity changes during the forward and backward extractions at various HNO$$_{3}$$ and TBP concentrations to investigate the reaction mechanism. This result indicates that one nitrate ion reacts with Eu(III) at the interface, whereas TBP molecules are not involved in the interfacial reaction, which is different from the results obtained using the NaNO$$_{3}$$ solution in our previous study. We demonstrate that the chemical species of Eu(III) complex with nitrate ion and TBP in the aqueous solution play an important role for the extraction mechanism.

Journal Articles

Hybrid process combining solvent extraction / low pressure loss extraction chromatography for a reasonable MA(III) recovery process

Sano, Yuichi; Sakamoto, Atsushi; Miyazaki, Yasunori; Watanabe, So; Morita, Keisuke; Emori, Tatsuya; Ban, Yasutoshi; Arai, Tsuyoshi*; Nakatani, Kiyoharu*; Matsuura, Haruaki*; et al.

Proceedings of International Conference on Nuclear Fuel Cycle; Sustainable Energy Beyond the Pandemic (GLOBAL 2022) (Internet), 4 Pages, 2022/07

We developed a hybrid MA(III) recovery process combining MA(III)+Ln(III) co-recovery flowsheet by solvent extraction with TBP and MA(III)/Ln(III) separation flowsheet by simulated moving bed chromatography using HONTA impregnated adsorbents with large particle size porous silica support.

Journal Articles

Sodium-cooled Fast Reactors

Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.

Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07

This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.

Journal Articles

Acid dissociation constant of bis(2-ethylhexyl) hydrogen phosphate impregnated in a polymer layer coated on silica microparticles

Miyagawa, Akihisa*; Takeuchi, Masayuki; Arai, Tsuyoshi*; Watanabe, So; Sano, Yuichi; Nakatani, Kiyoharu*

Bulletin of the Chemical Society of Japan, 95(4), p.566 - 568, 2022/04

 Times Cited Count:3 Percentile:40.16(Chemistry, Multidisciplinary)

We demonstrate that pKa of extractant impregnated in a polymer phase varies with the cross-linking degree and the coexistence of other extractants, which induces a change in the hydrophobicity of the polymer phase. The results presented herein will be beneficial for the development of novel solid-extraction adsorbents.

Journal Articles

PSTEP: Project for solar-terrestrial environment prediction

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:49.29(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.

Journal Articles

Safety assessment of adsorbent for extraction chromatography and effect on radiation of separation operation

Miyazaki, Yasunori; Sano, Yuichi

Hoshasen Kagaku (Internet), (112), p.27 - 32, 2021/11

no abstracts in English

Journal Articles

Development of MA separation process with TEHDGA/SiO$$_{2}$$-P for an advanced reprocessing

Horiuchi, Yusuke; Watanabe, So; Sano, Yuichi; Takeuchi, Masayuki; Kida, Fukuka*; Arai, Tsuyoshi*

Journal of Radioanalytical and Nuclear Chemistry, 330(1), p.237 - 244, 2021/10

 Times Cited Count:7 Percentile:70.8(Chemistry, Analytical)

Applicability of tetra2-ehylhexyl diglycolamide (TEHDGA) impregnated adsorbent for minor actinide (MA) recovery from high level liquid waste (HLLW) in extraction chromatography technology was investigated through batch-wise adsorption and column separation experiments. Distribution ratio of representative fission product elements were obtained by the batch-wise experiments, and TEHDGA adsorbent was shown to be preferable to TODGA adsorbent for decontamination of several species. All Ln(III) supplied into the TEHDGA adsorbent packed column was properly eluted from the column, and the applicability of the adsorbent was successfully showed by this study.

JAEA Reports

Evaluation of the mass transfer coefficients for the minor actinide separation; Evaluation by the single drop method

Sakamoto, Atsushi; Kibe, Satoshi*; Kawanobe, Kazunori*; Fujisaku, Kazuhiko*; Sano, Yuichi; Takeuchi, Masayuki; Suzuki, Hideya*; Tsubata, Yasuhiro; Ban, Yasutoshi; Matsumura, Tatsuro

JAEA-Research 2021-003, 30 Pages, 2021/06


Japan Atomic Energy Agency has been developing a solvent extraction process called SELECT to recover minor actinides (MA) from spent nuclear fuel. In the SELECT process, TDdDGA, HONTA, and ADAAM are used as the extractants for MA + Ln corecovery, MA/Ln separation and Am/Cm separation, respectively. These extractants do not contain phosphorus (P), and consist of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N). In this study, in order to give beneficial information for designing flowsheet, the mass transfer coefficients of Ln between HNO$$_{3}$$ solution and TDdDGA or HONTA / n-dodecane solvent were evaluated by the single drop technique. Prior to the evaluation of mass transfer coefficient, we had optimized the structure of the single drop apparatus to improve accuracy of the measurement. Based on the mass transfer coefficients obtained in HNO$$_{3}$$ / TDdDGA-n-dodecane system, Ln behaviors in the counter-current extraction and back-extraction using mixer-settlers and centrifugal contactors were estimated by simple calculation, and they had a good agreement with our previous experimental results. We also confirmed the mass transfer coefficients of Ln in HNO$$_{3}$$ / HONTA - n-dodecane system are under 10$$^{-6}$$ m/s.

Journal Articles

Behavior of light elements in iron-silicate-water-sulfur system during early Earth's evolution

Iizuka, Riko*; Goto, Hirotada*; Shito, Chikara*; Fukuyama, Ko*; Mori, Yuichiro*; Hattori, Takanori; Sano, Asami; Funakoshi, Kenichi*; Kagi, Hiroyuki*

Scientific Reports (Internet), 11(1), p.12632_1 - 12632_10, 2021/06

 Times Cited Count:3 Percentile:30.98(Multidisciplinary Sciences)

The Earth's core consist of Fe-Ni alloy with some light elements (H, C, O, Si, S etc.). Hydrogen (H) is the most abundant element in the universe and one of the promising candidates. In this study, we have investigated the effects of sulfur(S) on hydrogenation of iron-hydrous silicate system containing saturated water in the ideal composition of the primitive Earth. We observed a series of phase transitions of Fe, dehydration of the hydrous mineral, and formation of olivine and enstatite with increasing temperature. The FeS formed as the coexisting phase of Fe under high-pressure and temperature condition, but its unit cell volume did not increase, suggesting that FeS is hardly hydrogenated. Recovered samples exhibited that H and S can be incorporated into solid Fe, which lowers the melting temperature as Fe(H$$_{x}$$)-FeS system. No detection of other light elements (C, O, Si) in solid Fe suggests that they dissolve into molten iron hydride and/or FeS in the later process of Earth's core-mantle differentiation.

Journal Articles

Study on gamma-ray-degradation of adsorbent for low pressure-loss extraction chromatography

Miyazaki, Yasunori; Sano, Yuichi; Okamura, Nobuo; Watanabe, Masayuki; Koka, Masashi*

QST-M-29; QST Takasaki Annual Report 2019, P. 72, 2021/03

no abstracts in English

Journal Articles

Neutron diffraction study of hydrogen site occupancy in Fe$$_{0.95}$$Si$$_{0.05}$$ at 14.7 GPa and 800 K

Mori, Yuichiro*; Kagi, Hiroyuki*; Kakizawa, Sho*; Komatsu, Kazuki*; Shito, Chikara*; Iizuka, Riko*; Aoki, Katsutoshi*; Hattori, Takanori; Sano, Asami; Funakoshi, Kenichi*; et al.

Journal of Mineralogical and Petrological Sciences, 116(6), p.309 - 313, 2021/00

 Times Cited Count:0 Percentile:0.02(Mineralogy)

The Earth's core is believed to contain some light elements because it is 10% less dense than pure Fe under the corresponding pressure and temperature conditions. Hydrogen, a promising candidate among light elements, has phase relations and physical properties that have been investigated mainly for the Fe-H system. This study specifically examined an Fe-Si-H system using in-situ neutron diffraction experiments to investigate the site occupancy of deuterium of hcp-Fez$$_{0.95}$$Si$$_{0.05}$$ hydride at 14.7 GPa and 800 K. Results of Rietveld refinement indicate hcp-Fe$$_{0.95}$$Si$$_{0.05}$$ hydride as having deuterium (D) occupancy of 0.24(2) exclusively at the interstitial octahedral site in the hcp lattice. The effect on the site occupancy of D by addition of 2.6 wt% Si into Fe (Fe$$_{0.95}$$Si$$_{0.05}$$) was negligible compared to results obtained from an earlier study of an Fe-D system (Machida et al., 2019).

333 (Records 1-20 displayed on this page)