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Journal Articles

Neutron diffraction study of the crystal and magnetic structures of antiferromagnetic manganese deuteride at high temperatures and high pressures

Machida, Akihiko*; Saito, Hiroyuki*; Aoki, Katsutoshi*; Komatsu, Kazuki*; Hattori, Takanori; Sano, Asami; Funakoshi, Kenichi*; Machida, Shinichi*; Sato, Toyoto*; Orimo, Shinichi*

Physical Review B, 111(22), p.224413_1 - 224413_6, 2025/06

 Times Cited Count:1

The crystal and magnetic structures of antiferromagnetic Mn deuterides formed by hydrogenating Mn metal at high temperature and high pressure, fcc $$gamma$$-MnDx and hcp $$epsilon$$-MnDx, were investigated by in-situ neutron powder diffraction. Deuterium atoms partially occupied the octahedral interstitial positions of the fcc and hcp metal lattices. The site occupancies increased rapidly with decreasing temperature from $$sim$$700 to $$sim$$450 K and remained down to 300 K. N$'{e}$el temperature of 543(10) K was determined for $$gamma$$-MnD$$_{0.34}$$. For $$epsilon$$-MnD$$_{0.62}$$, saturation magnetic moment and N$'{e}$el temperature were determined to be 0.82(1) $$mu_B$$ and 347(3) K, respectively. The N$'{e}$el temperatures determined for $$gamma$$-MnD$$_{0.34}$$ and $$epsilon$$-MnD$$_{0.62}$$ are consistent with those predicted by the respective Slater-Pauling curves proposed in previous studies. The updated N$'{e}$el temperatures provide insights into the development of more accurate Slater-Pauling curves based on electronic band structure calculations.

Journal Articles

Electrocatalytic nitrous oxide reduction reaction at Sn-modified Pd-Pt single crystalline electrodes in acidic media

Kato, Masaru*; Zheng, J.*; Deng, Y.*; Saito, Fumie*; Unuma, Yuki*; Oka, Sayuki*; Tamura, Kazuhisa; Yagi, Ichizo*

ACS Catalysis, 15(10), p.7710 - 7719, 2025/04

 Times Cited Count:0 Percentile:0.00(Chemistry, Physical)

Journal Articles

Mechanical multiplexer of nuclear spin states

Chudo, Hiroyuki; Yokoi, Naoto*; Matsuo, Mamoru; Harii, Kazuya*; Suzuki, Jun*; Imai, Masaki; Sato, Masahiro*; Maekawa, Sadamichi*; Saito, Eiji*

Physical Review Letters, 134(13), p.130603_1 - 130603_5, 2025/04

 Times Cited Count:0 Percentile:0.00(Physics, Multidisciplinary)

JAEA Reports

Conceptual study of J-PARC Proton Beam Irradiation Facility

Meigo, Shinichiro; Iwamoto, Hiroki; Sugihara, Kenta*; Hirano, Yukinori*; Tsutsumi, Kazuyoshi*; Saito, Shigeru; Maekawa, Fujio

JAEA-Technology 2024-026, 123 Pages, 2025/03

JAEA-Technology-2024-026.pdf:14.22MB

Based on the design of the ADS Target Test Facility (TEF-T) at the J-PARC Transmutation Experimental Facility, a conceptual study was conducted on the J-PARC proton beam irradiation facility. This research was carried out based on the recommendations of the Nuclear Transmutation Technology Evaluation Task Force of the MEXT. The recommendations state that it is desirable to consider facility specifications that can make the most of the benefits of using the existing J-PARC proton accelerator while also solving the engineering issues of the ADS. We considered facilities that could respond to a variety of needs while reducing the facilities that were not needed in the TEF-T design. In order to clarify these diverse needs, we investigated the usage status of representative accelerator facilities around the world. As a result, it became clear that the main purposes of these facilities were (1) Material irradiation, (2) Soft error testing of semiconductor devices using spallation neutrons, (3) Production of RI for medical use, and (4) Proton beam use, and we investigated the facilities necessary for these purposes. In considering the facility concept, we assumed a user community in 2022 and reflected user opinions in the facility design. This report summarizes the results of the conceptual study of the proton irradiation facility, various needs and responses to them, the roadmap for facility construction, and future issues.

Journal Articles

A Decade of neutron diffraction study of iron hydrides

Aoki, Katsutoshi*; Machida, Akihiko*; Saito, Hiroyuki*; Hattori, Takanori

Koatsuryoku No Kagaku To Gijutsu, 35(1), p.4 - 11, 2025/03

Iron reacts with hydrogen to form solid solutions with body-centered cubic, face-centered cubic, hexagonal close packed, and double hexagonal close packed structures at high temperatures and high pressures. Neutron diffraction is the most powerful tool for determining the occupation sites and occupancies of hydrogen atoms dissolved in a metal lattice. Structural parameters, including hydrogen occupation sites and occupancies, are refined via Rietveld analysis for neutron diffraction data. We present our expertise in Rietveld refinement of iron hydrides accumulated over 10 years.

Journal Articles

Stress and plastic strain partitioning behaviors and those contributions to martensitic transformation of retained austenite in medium manganese and transformation-induced plasticity-aided bainitic ferrite steels

Hojo, Tomohiko*; Koyama, Motomichi*; Kumai, Bakuya*; Zhou, Y.*; Shibayama, Yuki; Shiro, Ayumi*; Shobu, Takahisa; Saito, Hiroyuki*; Ajita, Saya*; Akiyama, Eiji*

ISIJ International, 65(2), p.284 - 296, 2025/02

 Times Cited Count:0

Journal Articles

Integrated radiation air dose rate maps over the 80 km radius of the Fukushima Daiichi Nuclear Power Plant and the entire Fukushima Prefecture during 2011-2022

Sakuma, Kazuyuki; Kurikami, Hiroshi; Wainwright, Haruko*; Tanimori, Soichiro*; Nagao, Fumiya; Ochi, Kotaro; Sanada, Yukihisa; Saito, Kimiaki

Journal of Environmental Radioactivity, 280, p.107554_1 - 107554_11, 2024/12

 Times Cited Count:2 Percentile:53.16(Environmental Sciences)

In this study, we created the integrated radiation air dose rate maps in the Fukushima region during 2011-2022 using multiple types of surveys such as air-borne, car-borne and walk surveys as well as fixed-location measurements. We applied the Bayesian geostatistical method developed by Wainwright et al. (2017, 2019) to the 80 km radius of the Fukushima Daiichi Nuclear Power Plant and the whole of Fukushima Prefecture while considering the history of the lifting of the evacuation zone in Fukushima. The integrated maps fixed the bias to underestimate air dose rates in forest areas, and successfully created more reproducible integrated maps with a wider area and time series than the previous studies. It is highly expected that the results of this study will be used to evaluate detailed exposure doses to the general public.

Journal Articles

Addendum: Site occupancy of interstitial deuterium atoms in face-centred cubic iron

Machida, Akihiko*; Saito, Hiroyuki*; Sugimoto, Hidehiko*; Hattori, Takanori; Sano, Asami; Endo, Naruki*; Katayama, Yoshinori*; Iizuka, Riko*; Sato, Toyoto*; Matsuo, Motoaki*; et al.

Nature Communications (Internet), 15, p.8861_1 - 8861_2, 2024/10

 Times Cited Count:0 Percentile:0.00(Multidisciplinary Sciences)

In our previous article (Nature Commun. 5, 5063 (2014)), the site occupancies of D atoms dissolved in an fcc Fe metal lattice were investigated via Rietveld refinement of neutron powder diffraction patterns collected at 988 K and 6.3 GPa. The fcc metal lattice has two interstitial sites available for accommodating D atoms: octahedral and tetrahedral sites. The Rietveld refinement revealed that D atoms occupied mainly the octahedral sites with occupancy of 0.532 and slightly the tetrahedral sites with occupancy of 0.056. Subsequent density-functional-theory (DFT) calculations by Antonov (Phys. Rev. Mater. 2019)) showed that the occupation energy on the tetrahedral site was significantly higher than that on the octahedral site; the tetrahedral site occupation was unlikely to occur even at temperatures as high as 988 K. We reexamined the site occupancies of D-atom by Rietveld refinement including extinction correction. As a result, the octahedral occupancy was increased to 0.60 and the tetrahedral occupancy was reduced to zero. The occupation of only the octahedral site for D atom is consistent with the DFT calculation, although in contrast to the previous results.

Journal Articles

Trivalent lanthanide sorption onto illite in the presence of carbonate; A Study combining thermodynamic sorption modeling, time-resolved laser fluorescence spectroscopy, and parallel factor analysis

Sugiura, Yuki; Ishidera, Takamitsu; Aoyagi, Noboru; Mei, H.; Saito, Takumi*; Tachi, Yukio

Applied Clay Science, 258, p.107476_1 - 107476_10, 2024/09

 Times Cited Count:2 Percentile:69.91(Chemistry, Physical)

Journal Articles

Evaluation of tritium monitoring data for ocean discharge of treated water

Sanada, Yukihisa; Urabe, Yoshimi*; Saito, Madoka*; Shiribiki, Takehiko*; Misono, Toshiharu; Funaki, Hironori

Kankyo Gijutsu, 53(4), p.188 - 193, 2024/07

no abstracts in English

JAEA Reports

Differential pressure rise event for filters of HTTR primary helium gas circulators, 2; Investigation of filter deposits and recurrence prevention measures

Nemoto, Takahiro; Fujiwara, Yusuke; Arakawa, Ryoki; Choyama, Yuya; Nagasumi, Satoru; Hasegawa, Toshinari; Yokoyama, Keisuke; Watanabe, Masashi; Onishi, Takashi; Kawamoto, Taiki; et al.

JAEA-Technology 2024-003, 17 Pages, 2024/06

JAEA-Technology-2024-003.pdf:1.91MB

In order to investigate the cause of the increase in differential pressure in the primary helium circulator filter that occurred during the RS-14 cycle, a clogged filter was investigated. As a result of the investigation, deposits caused by silicone oil were confirmed on the surface of the filter element. These results revealed that the cause of filter clogging was silicone oil mixed into the primary system due to performance deterioration of the charcoal filter in the gas circulator of primary helium purification system. As a measure to prevent the recurrence of this event, in addition to the conventional management based on operating hours for replacing of charcoal filter in the gas circulator of primary helium purification system, we have established a new replacement plan for every three years.

Journal Articles

Globular pattern formation of hierarchical ceria nanoarchitectures

Aoyagi, Noboru; Motokawa, Ryuhei; Okumura, Masahiko; Ueda, Yuki; Saito, Takumi*; Nishitsuji, Shotaro*; Taguchi, Tomitsugu*; Yomogida, Takumi; Sazaki, Gen*; Ikeda, Atsushi

Communications Chemistry (Internet), 7, p.128_1 - 128_13, 2024/06

 Times Cited Count:0 Percentile:0.00(Chemistry, Multidisciplinary)

Journal Articles

"Invisible" radioactive cesium atoms revealed; Pollucite inclusion in cesium-rich microparticles (CsMPs) from the Fukushima Daiichi Nuclear Power Plant

Miyazaki, Kanako*; Takehara, Masato*; Minomo, Kenta*; Horie, Kenji*; Takehara, Mami*; Yamasaki, Shinya*; Saito, Takumi*; Onuki, Toshihiko*; Takano, Masahide; Shiotsu, Hiroyuki; et al.

Journal of Hazardous Materials, 470(15), p.134104_1 - 134104_11, 2024/05

 Times Cited Count:1 Percentile:31.14(Engineering, Environmental)

Journal Articles

Determination of $$^{90}$$Sr in highly radioactive aqueous samples via conversion to a kinetically stable 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid complex followed by concentration-separation-fractionation based on capillary electrophoresis-liquid scintillation

Ouchi, Kazuki; Haraga, Tomoko; Hirose, Kazuki*; Kurosawa, Yuika*; Sato, Yoshiyuki; Shibukawa, Masami*; Saito, Shingo*

Analytica Chimica Acta, 1298, p.342399_1 - 342399_7, 2024/04

 Times Cited Count:1 Percentile:34.56(Chemistry, Analytical)

Given that conventional methods of high-dose sample analysis pose substantial exposure risks and generate large amounts of secondary radioactive waste, faster procedures allowing for decreased radiation emission are highly desirable. To address this need, we developed a $$^{90}$$Sr$$^{2+}$$ quantitation technique that is based on liquid scintillation counting-coupled capillary transient isotachophoresis (ctITP) with two-point detection and relies on the rapid concentration, separation, and fractionation of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-complexed $$^{90}$$Sr$$^{2+}$$ in a single run. This method, which allows for the handling of high-dose radioactive specimens at the microliter level and is substantially faster than conventional ion-exchange protocols, was used to selectively quantify $$^{90}$$Sr$$^{2+}$$ in real high-dose waste. The successful concentration-separation in ctITP was ascribed to the inertness of the Sr-DOTA complex to dissociation.

Journal Articles

Microbiome analysis of the restricted bacteria in radioactive element-containing water at the Fukushima Daiichi Nuclear Power Station

Warashina, Tomoro*; Sato, Asako*; Hinai, Hiroshi; Shaikhutdinov, N.*; Shagimardanova, E.*; Mori, Hiroshi*; Tamaki, Satoshi*; Saito, Motofumi*; Sanada, Yukihisa; Sasaki, Yoshito; et al.

Applied and Environmental Microbiology, 90(4), p.e02113-23_1 - e02113-23_23, 2024/04

 Times Cited Count:0 Percentile:0.00(Biotechnology & Applied Microbiology)

Journal Articles

Polarized neutron diffraction study on UPt$$_{2}$$Si$$_{2}$$

Kon, Fusako*; Tabata, Chihiro; Saito, Hiraku*; Nakajima, Taro*; Hidaka, Hiroyuki*; Yanagisawa, Tatsuya*; Amitsuka, Hiroshi*

Journal of the Physical Society of Japan, 93(4), p.044701_1 - 044701_11, 2024/04

 Times Cited Count:0 Percentile:0.00(Physics, Multidisciplinary)

Journal Articles

Simulation of predicted effects of decontamination and cultivation activities on reduction of air dose rates using Monte Carlo method

Kim, M.; Yoshimura, Kazuya; Sakuma, Kazuyuki; Malins, A.*; Abe, Tomohisa; Nakama, Shigeo; Machida, Masahiko; Saito, Kimiaki

Kankyo Hoshano Josen Gakkai-Shi, 12(2), p.39 - 53, 2024/04

More than ten years have passed since the accident at TEPCO's Fukushima Daiichi Nuclear Power Station. But with the progress of decontamination, the evacuation order has been lifted and the return of residents is still ongoing. Under these circumstances, in order to quantitatively evaluate the effect of decontamination activities and cultivation on air dose rate reduction, a detailed environmental model was constructed using 3D-ADRES for a real area located in the Okuma town, Fukushima prefecture. Monte Carlo simulations were performed using the model to calculate realistic distributions of radioactive Cs based on measurement results and air dose rates reflecting changes over time. As a result, the distribution of air dose rates at 100 cm above ground level in the target area according to decontamination and cultivation activities was calculated. The calculated air dose rates reproduced the measured values well, and were confirmed to be appropriate as a method for evaluating the effects of decontamination and cultivation activities. This method is expected to serve as a reference for further decontamination management measures to reduce the air dose rate in the difficult-to-return zone, where entry is still restricted.

Journal Articles

Performance comparison of monoamides on U recovery by temperature swing extraction using Ce

Iwamoto, Toshihiro; Saito, Madoka*; Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Naruse, Atsuki*; Tsukahara, Takehiko*

Mechanical Engineering Journal (Internet), 11(2), p.23-00444_1 - 23-00444_7, 2024/04

JAEA Reports

Conceptual study of Post Irradiation Examination (PIE) Facility at J-PARC

Saito, Shigeru; Meigo, Shinichiro; Makimura, Shunsuke*; Hirano, Yukinori*; Tsutsumi, Kazuyoshi*; Maekawa, Fujio

JAEA-Technology 2023-025, 48 Pages, 2024/03

JAEA-Technology-2023-025.pdf:3.11MB

JAEA has been developing Accelerator-Driven Systems (ADS) for research and development of nuclear transmutation using accelerators in order to reduce the volume and hazardousness of high-level radioactive waste generated by nuclear power plants. In order to prepare the material irradiation database necessary for the design of ADS and to study the irradiation effects in Lead-Bismuth Eutectic (LBE) alloys, a proton irradiation facility is under consideration at J-PARC. In this proton irradiation facility, 250 kW proton beams will be injected into the LBE spallation target, and irradiation tests under LBE flow will be performed for candidate structural materials for ADS. Furthermore, semiconductor soft-error tests, medical RI production, and proton beam applications will be performed. Among these, Post Irradiation Examination (PIE) of irradiated samples and RI separation and purification will be carried out in the PIE facility to be constructed near the proton irradiation facility. In this PIE facility, PIE of the equipment and samples irradiated in other facilities in J-PARC will also be performed. This report describes the conceptual study of the PIE facility, including the items to be tested, the test flow, the facilities, the test equipment, etc., and the proposed layout of the facility.

Journal Articles

Evaluation on cementation by silicates in bentonite

Saito, Yuki*; Ishiwata, Tobimaru*; Horiuchi, Misato*; Nishiki, Yuto*; Kikuchi, Ryosuke*; Otake, Tsubasa*; Kawakita, Ryohei; Takayama, Yusuke; Mitsui, Seiichiro; Sato, Tsutomu*

Shigen, Sozai Koenshu (Internet), 11(1), 7 Pages, 2024/03

no abstracts in English

1346 (Records 1-20 displayed on this page)