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Asahina, Daisuke*; Takamura, Hiroaki*; Tsukamoto, Koji*; Honda, Fumito*; ITO, Takashi*; IWATA, Naoki*; Aydan, 
mer*; Sato, Toshinori
Dai-51-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu(Internet), p.43 - 47, 2025/12
Fault zones commonly contain distinctive structures such as fault cores and damage zones, where physical properties vary locally. These zones are important for evaluating underground safety and groundwater flow in waste disposal, yet quantitative measurements near faults remain limited. We applied Schmidt hammer and needle penetration tests to assess the mechanical properties of the rocks near the Tanakura Fault, in a simple, non-destructive manner. The results showed a clear spatial variation in measured values with distance from the fault gouge boundary, suggesting that combining methods with different scales and sensitivities can provide a more comprehensive evaluation of rock mass properties near faults.
Iketani, Shotaro; Suzuki, Takeshi; Yokobori, Tomohiko; Sugawara, Satoshi; Yokota, Akira; Kikuchi, Genta; Muraguchi, Yoshinori; Kitahara, Masaru; Seya, Manato; Kurosawa, Tsuyoshi; et al.
JAEA-Technology 2025-001, 169 Pages, 2025/08
JAEA-Technology-2025-001.pdf:14.22MB
The radioactive waste treatment facilities at the Nuclear Science Research Institute includes the Radioactive Waste Treatment Facility No. 3, Waste Size Reduction and Storage Facility, and Waste Volume Reduction Facility. These three facilities come under the purview of the Act on the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors, and are included under Class C of the act based on the seismic requirements specified in the Act. We assessed the seismic capacity of these three radioactive waste treatment facilities based on the current Building Standards Act, to verify whether they comply with the new regulatory requirements enforced by the Nuclear Regulation Authority (NRA) in the aftermath of the 2011 nuclear accident at the Fukushima Daiichi Nuclear Power Station operated by the Tokyo Electric Power Company. We found that the allowable stress of a few structural members used in the construction of the facilities did not meet the regulatory requirements. After studying the approval granted by the NRA for the construction plans, including the design and construction methods (design and construction plans) of the three facilities on March 5, 2021, we made aseismic reinforcement at these facilities between 2021 and 2022. This report presents an overview of the seismic design of these facilities and an outline of the aseismic reinforcement conducted, management system existing, safety measures adopted, and the preoperational inspections conducted at these facilities.
Co
)Sn studied by 
SRCai, Y.*; Yoon, S.*; Sheng, Q.*; Zhao, G.*; Seewald, E. F.*; Ghosh, S.*; Ingham, J.*; Pasupathy, A. N.*; Queiroz, R.*; Lei, H.*; et al.
Physical Review B, 111(21), p.214412_1 - 214412_17, 2025/06
Times Cited Count：2 Percentile：68.54(Materials Science, Multidisciplinary)Masuki, Yuma*; Katsuta, Nagayoshi*; Naito, Sayuri*; Murakami, Takuma*; Umemura, Ayako*; Fujita, Natsuko; Matsubara, Akihiro*; Minami, Masayo*; Niwa, Masakazu; Yoshida, Hidekazu*; et al.
Journal of Hazardous Materials, 485, p.136843_1 - 136843_10, 2025/03
Times Cited Count：2 Percentile：10.15(Engineering, Environmental)Lacustrine deposits have 30-fold higher As abundance than the average crustal deposit. Arsenic is mostly concentrated as discrete horizons deposited in spring and autumn. As-rich layers contain FeAsS, AsS, and As
S
but As-rich hotspots mostly contain FeAsS. As accumulation to sediment is controlled by redox potential with organic matter.
Owada, Mitsuhiro; Nakanishi, Yoshiki; Murokawa, Toshihiro; Togashi, Kota; Saito, Katsunori; Nonaka, Kazuharu; Sasaki, Yu; Omori, Koji; Chinone, Makoto; Yasu, Hideto; et al.
JAEA-Technology 2024-013, 221 Pages, 2025/02
JAEA-Technology-2024-013.pdf:14.98MB
The uranium enrichment facilities at the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency (JAEA) were constructed sequentially to develop uranium enrichment technology with centrifugal separation method. The developed technologies were transferred to Japan Nuclear Fuel Limited until 2001. And the original purpose has been achieved. Wastewater Treatment Facility, one of the uranium enrichment facilities, was constructed in 1976 to treat radioactive liquid waste generated at the facilities, and it finished the role in 2008. In accordance with the Medium/Long-Term Management Plan of JAEA Facilities, interior equipment installed in this facility had been dismantled and removed since November 2021 to August 2023. This report summarizes the findings obtained through the work related to dismantling and removal of interior equipment for decommissioning of Wastewater Treatment Facility.
Toyama, Takeshi*; Tanno, Takashi; Yano, Yasuhide; Inoue, Koji*; Nagai, Yasuyoshi*; Otsuka, Satoshi; Miyazawa, Takeshi; Mitsuhara, Masatoshi*; Nakashima, Hideharu*; Onuma, Masato*; et al.
Journal of Nuclear Materials, 599, p.155252_1 - 155252_14, 2024/10
Times Cited Count：4 Percentile：62.63(Materials Science, Multidisciplinary)We investigated the stability of oxide nano particles in oxide dispersion-strengthened (ODS) steel, which is a promising candidate material for next-generation reactors, under neutron irradiation at high temperature to high doses. MA957, a 14Cr-ODS steel, was irradiated with Joyo in Japan Atomic Energy Agency under irradiation conditions of 130 dpa at 502
C, 154 dpa at 589C, and 158 dpa at 709C. Three-dimensional atom probe (3D-AP) and transmission electron microscope (TEM) observation were performed to characterize the oxide particles in the ODS steels. A high number density of Y-Ti-O particle was observed in the unirradiated and irradiated samples. Almost no change in the morphology of the oxide particles, i.e. average diameter, number density, and chemical composition, has been observed in the samples irradiated to 130 dpa at 502C and to 154 dpa at 589C. A slight decrease in number density was observed in the sample irradiated to 158 dpa at 709CC. The hardness of any of the irradiated samples was almost unchanged from that of the unirradiated sample. It was revealed that the oxide particles existed stable, and the strength of the material was sufficiently maintained even after being neutron irradiated to high dose of 
160 dpa at high temperature up to 700C. A part of this study includes the results of MEXT Innovative Nuclear Research and Development Program Grant Number JPMXD0219214482.
-dioctylthiodiglycolamic acid; Effect of S donor on metal extractionShimojo, Kojiro; Fujiwara, Iori*; Saito, Takumi*; Oshima, Tatsuya*
Analytical Sciences, 40(8), p.1429 - 1436, 2024/08
Times Cited Count：1 Percentile：0.00(Chemistry, Analytical)Extraction ability of -dioctylthiodiglycolamic acid (T-DODGAA), a soft-base sulfur donor ligand with an amide group and a carboxylic acid connected by a thioether chain, for 56 metal ions have been comprehensively investigated and compared with that of N,N-dioctyldiglycolamic acid (DODGAA) with an etheric oxygen atom, a hard-base donor. The p
of the thiodiglycolamic acid framework was determined to be 3.71 
0.06 in water (0.1 M LiCl, 25C ) by potentiometric titration, indicating that T-DODGAA is a slightly weaker acid than DODGAA (p = 3.54 0.03). T-DODGAA can quantitatively extract various metal ions from the 56 metal ions through a proton-exchange reaction. T-DODGAA provided higher extraction performance than DODGAA for Hf(IV), Cr(III), Fe(III), Ni(II), Cu(II), Pd(II), Ag(I), Au(III), Hg(II), Al(III), and Ga(III), especially for soft metal ions. Furthermore, to demonstrate the practical feasibility of T-DODGAA for hydrometallurgy and metal recycling, we performed selective separation tests of rare metal ions such as Sc(III), Ni(II), Co(II), Pd(II), Au(III), In(III), and Ga(II) in metal-mixed extraction systems.
shetta lakes in the Soya Coast region and their paleoenvironmental significance with glacial isostatic adjustment in East AntarcticaInoue, Genki*; Honda, Eisuke*; Ito, Keisuke*; Kang, I.*; Seto, Koji*; Tani, Yukinori*; Watanabe, Takahiro; Kashima, Kaoru*; Otani, Shuji*; Yamanaka, Toshiro*; et al.
Quaternary Science Reviews, 338, p.108822_1 - 108822_18, 2024/08
Times Cited Count：0 Percentile：0.00(Geography, Physical)We studied Holocene paleolimnological changes inferred from biomarkers and microscopic observation of microalgae and cyanobacteria in sediment cores from Rundvshetta lakes (Maruwanminami-ike and Maruwan o-ike) in the Soya Coast of East Antarctica, along with sedimentary facies and radiocarbon dating. Coastal marine environment: Maruwanminami-ike (147-72.5 cm, 5,010-2,590 cal BP) and Maruwan-oike (226-47.2 cm, 5,700-3,190 cal BP) were characterized by low biological production with the predominance of diatoms. Transition period of stratified brackish lake environment: Maruwanminami-ike (72.5-65.6 cm, 2,590-2,500 cal BP) and Maruwan-oike (47.2-28.8 cm, 3,190-2,890 cal BP) were characterized by stratified conditions with marine water overlain by freshwater, and a chemocline developed together with an anoxic layer in the bottom of photic zone.
Hattori, Takanori; Suzuki, Koji*; Miyo, Tatsuya*; Ito, Takayoshi*; Machida, Shinichi*
Nuclear Instruments and Methods in Physics Research A, 1064, p.169448_1 - 169448_9, 2024/07
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)The authors regret that the abstract and summary explain that the cup diameter of a standard double-toroidal anvils is 1.5 mm. This is incorrect; the standard diameter is 4.0 mm. The authors would like to apologise for any inconvenience caused.
Hoshi, Kojiro*; Hioki, Tomosato*; Saito, Eiji
Physical Review Applied (Internet), 21(6), p.064057_1 - 064057_6, 2024/07
Times Cited Count：1 Percentile：13.00(Physics, Applied)Ichikawa, Tsubasa*; Hakoshima, Hideaki*; Inui, Koji*; Ito, Kosuke*; Matsuda, Ryo*; Mitarai, Kosuke*; Miyamoto, Koichi*; Mizukami, Wataru*; Mizuta, Kaoru*; Mori, Toshio*; et al.
Nature Reviews Physics (Internet), 6(6), p.345 - 347, 2024/06
Times Cited Count：13 Percentile：98.48(Physics, Applied)Saito, Toshiki*; Yu, H.*; Gao, Z.*; Inoue, Koji*; Kondo, Sosuke*; Kasada, Ryuta*; Nagai, Yasuyoshi*; Oba, Yojiro*; Hiroi, Kosuke
Journal of Alloys and Compounds, 983, p.173852_1 - 173852_12, 2024/05
Times Cited Count：8 Percentile：73.51(Chemistry, Physical)Makiuchi, Takahiko*; Hioki, Tomosato*; Shimizu, Hiroki*; Hoshi, Kojiro*; Elyasi, M.*; Yamamoto, Kei; Yokoi, Naoto*; Serga, A. A.*; Hillebrands, B.*; Bauer, G. E. W.*; et al.
Nature Materials, 23(5), p.627 - 632, 2024/05
Times Cited Count：20 Percentile：90.20(Chemistry, Physical)Hattori, Takanori; Suzuki, Koji*; Miyo, Tatsuya*; Ito, Takayoshi*; Machida, Shinichi*
Nuclear Instruments and Methods in Physics Research A, 1059, p.168956_1 - 168956_9, 2024/02
Times Cited Count：2 Percentile：32.62(Instruments & Instrumentation)Radial collimators (RC) with a 0.5 mm gauge size (GS) were specially designed for high-pressure neutron diffraction experiments and their performance and efficacy were investigated. The RCs with nominal GS of 0.75 mm, 1.5 mm, and 3.0 mm effectively exhibited GS of 0.50 mm, 1.07 mm, and 2.78 mm, respectively. The transmissions of all three RCs were almost equivalent. The assessment using a P-E press and a DAC revealed that the anvil scattering was considerably minimized and the sample-to-anvil signal ratio reached values of 0.5 and 2.0 for the PE press and DAC, respectively, when using the 0.5 mm-GS RCs. These results indicate that the 0.5mm-GS RCs have been fabricated as intended and exhibit efficacy for the high-pressure-neutron diffraction experiments, specifically those exceeding 30 GPa. Among those ever manufactured for neutron scattering experiments, the RCs display the smallest GS.
Taniguchi, Koji*; Huang, P.-J.*; Sagayama, Hajime*; Kiyanagi, Ryoji; Oishi, Kazuki*; Kito, Shunsuke*; Nakamura, Yuiga*; Miyasaka, Hitoshi*
Physical Review Materials (Internet), 8(2), p.024409_1 - 024409_10, 2024/02
Times Cited Count：7 Percentile：56.75(Materials Science, Multidisciplinary)Ikeda, Kazutaka*; Sashida, Sho*; Otomo, Toshiya*; Oshita, Hidetoshi*; Honda, Takashi*; Hawai, Takafumi*; Saito, Hiraku*; Ito, Shinichi*; Yokoo, Tetsuya*; Sakaki, Koji*; et al.
International Journal of Hydrogen Energy, 51(Part A), p.79 - 87, 2024/01
Times Cited Count：7 Percentile：36.81(Chemistry, Physical)
Fe
O
/Pt bilayer diskEmdi, G.*; Hioki, Tomosato*; Hoshi, Kojiro*; Saito, Eiji
Physical Review B, 108(14), p.L140410_1 - L140410_6, 2023/10
Times Cited Count：2 Percentile：16.04(Materials Science, Multidisciplinary)Horibe, Sohei*; Shimizu, Hiroki*; Hoshi, Kojiro*; Makiuchi, Takahiko*; Hioki, Tomosato*; Saito, Eiji
Applied Physics Express, 16(7), p.073001_1 - 073001_4, 2023/07
Times Cited Count：1 Percentile：7.13(Physics, Applied)Nagai, Yuya; Shuji, Yoshiyuki; Kawasaki, Takeshi; Aita, Takahiro; Kimura, Yasuhisa; Nemoto, Yasunori*; Onuma, Takeshi*; Tomiyama, Noboru*; Hirano, Koji*; Usui, Yasuhiro*; et al.
JAEA-Technology 2022-039, 117 Pages, 2023/06
JAEA-Technology-2022-039.pdf:11.96MB
Japan Atomic Energy Agency (JAEA) manages wide range of nuclear facilities. Many of these facilities are required to be performed adjustment with the aging and complement with the new regulatory standards and the earthquake resistant, since the Great East Japan Earthquake and the Fukushima Daiichi Nuclear Power Station accident. It is therefore desirable to promote decommissioning of facilities that have reached the end of their productive life in order to reduce risk and maintenance costs. However, the progress of facility decommissioning require large amount of money and radioactive waste storage space. In order to address these issues, JAEA has formulated a "The Medium/Long-Term Management Plan of JAEA Facilities" with three pillars: (1) consolidation and prioritization of facilities, (2) assurance of facility safety, and (3) back-end countermeasures. In this plan, Plutonium Fuel Fabrication Facility has been selected as primary decommissioned facility, and dismantling of equipment in the facilities have been underway. In this report, size reduction activities of the glove box W-9 and a part of tunnel F-1, which was connected to W-9, are presented, and the obtained findings are highlighted. The glovebox W-9 had oxidation & reduction furnace, and pellet crushing machine as equipment interior. The duration of activity took six years from February 2014 to February 2020, including suspended period of 4 years due to the enhanced authorization approval process.
Machida, Masahiko; Shi, W.*; Yamada, Susumu; Miyamura, Hiroko; Yoshida, Toru*; Hasegawa, Yukihiro*; Okamoto, Koji; Aoki, Yuto; Ito, Rintaro; Yamaguchi, Takashi; et al.
Proceedings of Waste Management Symposia 2023 (WM2023) (Internet), 11 Pages, 2023/02
