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Asamori, Koichi; Sueoka, Shigeru; Komatsu, Tetsuya; Ogata, Manabu; Uchida, Mao; Nishiyama, Nariaki; Tanaka, Kiriha; Akiyama, Reina; Kobayashi, Tomoharu; Mitsuguchi, Takehiro; et al.
JAEA-Review 2026-028, 29 Pages, 2026/09
JAEA-Review-2026-028.pdf:1.05MB
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2026. The objectives and contents of this research are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
Koda, Akihiro*; Ito, Takashi; Hiraishi, Masatoshi*; Okabe, Hirotaka*; Kadono, Ryosuke*
Physical Review B, 114(2), p.L020101_1 - L020101_7, 2026/07
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)Harada, Masahide; Yamaguchi, Yuji; Hashimoto, Norimichi*; Ito, Taku*; Tajima, Takahiro*; Oku, Takayuki; Haga, Katsuhiro; Ikeda, Hiroshi*; Tamura, Satoshi*
JPS Conference Proceedings (Internet), 45, p.011184_1 - 011184_4, 2026/06
At Materials and Life Science Facility in J-PARC, 3 GeV and 1 MW pulsed proton beam hits mercury and carbon targets and intense neutron and muon beams are provided for various measurements. As samples in the measurements are activated, estimation of radioactivity of samples is very necessary for a radiation safety of user experiments. Therefore, estimation system, SAmple Radioactivity Evaluation program (SARE), is developed. SARE can estimate radioactivity of samples at each neutron and muon beam line with neutron flux and activation cross section. The neutron flux data was applied from references and the activation cross section data was obtained from DCHAIN-SP-2001. The activation of negative-muon can be also estimated from a database. SARE has a user-friendly interface of Web servlet based on JAVA and JAVA script and can select various conditions for the estimation. In the presentation, we will introduce SARE and validation results performed at BL10 with the foil-activation method.
Kurita, Keisuke; Iikura, Hiroshi; Harayama, Isao; Tsuchikawa, Yusuke; Morooka, Satoshi; Kai, Tetsuya; Shinohara, Takenao; Odaira, Naoya*; Ito, Daisuke*; Saito, Yasushi*; et al.
Proceedings of 12th World Conference on Neutron Radiography; Springer Proceedings in Physics, Vol.348, p.244 - 251, 2026/06
Times Cited Count：0At the resumption of JRR-3 operations in 2021 after a 10-year shutdown, only an imaging system using imaging plates (IPs) was available at the CNRF. Although high-resolution images could be acquired, the system was unsuitable for continuous imaging required for computed tomography (CT) scans and dynamic imaging. It was also difficult to perform quantitative analysis from the images. To resolve these problems, we have introduced a new imaging system with a dark box, a scintillator, and a CMOS camera (Hamamatsu Photonics, ORCA Flash 4.0 V3). In this presentation, the performance of the imaging system, usage examples of the CNRF, and its results will be presented.
Kondo, Masatoshi*; Kitamura, Yoshiki*; Kawarai, Atsushi*; Saito, Shigeru; Obayashi, Hironari
Corrosion Science, 262, p.113646_1 - 113646_14, 2026/04
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)The corrosion resistance of FeCrAl alloy APMT (Fe-21Cr-5Al-3Mo) in flowing lead-bismuth eutectic (LBE) was investigated by corrosion tests performed at 723 K using a non-isothermal forced convection loop. The oxygen concentration in flowing LBE was controlled at 1
10
wt%. No severe corrosion or erosion was detected on the specimens exposed to flowing LBE for 2000 h and 4000 h. Multiple oxide layers consisting of Fe-rich, Cr-rich and Al-rich sub-layers were formed in situ on the surface of APMT during the corrosion tests, which effectively suppressed corrosion and erosion. The oxide layers were intentionally removed by gentle abrasion prior to re-immersion and the specimens were then re-immersed in flowing LBE for an additional 2000 h. The oxide layers were spontaneously re-formed in situ on the abraded surface. This behavior indicates a self-healing capability. The results of micro-scratch tests indicated that the in-situ formed multiple oxide layers exhibited high adhesion strength in the shear direction after the 2000 h corrosion test.
Kondo, Yasuhiro; Chimura, Motoki; Cicek, E.*; Fukui, Yuji*; Futatsukawa, Kenta*; Fuwa, Yasuhiro; Goto, Rikuto*; Hirano, Koichiro; Ishikawa, Masaki*; Ito, Takashi; et al.
Proceedings of 22nd Annual Meeting of Particle Accelerator Society of Japan (Internet), p.124 - 129, 2026/03
Various upgrade plans of the J-PARC linac are underway, and repetition-rate doubling project is one of the most important part. Currently, the linac supplies a 400~MeV H
ion beam to the 3~GeV synchrotron (RCS) at a repetition rate of 25~Hz. However, to deliver the beam to both RCS and proton-beam irradiation facility under planning, it is necessary to raise the repetition rate from 25~Hz to 50~Hz. Prior to construction of the beamline to the irradiation facility, we conducted a verification of the 50~Hz operation of all the linac apparatus simultaneously within the current operational limits in May 2025. And also, the verification of the 50~Hz operation of the particle counter system, which is one of the most important safety device of the J-PARC accelerator, was conducted. As a result, any significant problems were not found out, and it is now ready for the upcoming 50~Hz-beam acceleration demonstration. This paper describes this details of the demonstration of the 50~Hz operation, without beam acceleration, of the J-PARC linac.
neutron diffraction at cryogenic temperaturesYamashita, Takayuki*; Harjo, S.; Gong, W.; Kawasaki, Takuro; Morito, Shigekazu*; Morooka, Satoshi; Fujii, Hidetoshi*; Tomota, Yo*
Journal of Alloys and Compounds, 1056, p.186668_1 - 186668_11, 2026/02
Times Cited Count：0 Percentile：0.00(Chemistry, Physical)
Pu
Am
O
Vauchy, R.; Horii, Yuta; Hirooka, Shun; Akashi, Masatoshi; Sunaoshi, Takeo*; Nakamichi, Shinya; Saito, Kosuke
Proceedings of 34th Nuclear Energy for New Europe (NENE2025) , p.232 - 238, 2026/01
Mikami, Satoshi; Saito, Kimiaki; Hokama, Tomonori; 9 of others*
Hoken Butsuri (Internet), 60(4), p.275 - 303, 2025/12
no abstracts in English
Liu, Y.*; Otani, Masashi*; Miyao, Tomoaki*; Nakazawa, Yuga*; Shibata, Takanori*; Nammo, Kesao*; Fang, Z.*; Futatsukawa, Kenta*; Fukui, Yuji*; Mizobata, Satoshi*; et al.
Proceedings of 16th International Particle Accelerator Conference (IPAC25) (Internet), p.855 - 857, 2025/11
Asamori, Koichi; Sueoka, Shigeru; Komatsu, Tetsuya; Ogata, Manabu; Uchida, Mao; Nishiyama, Nariaki; Tanaka, Kiriha; Kobayashi, Tomoharu; Mitsuguchi, Takehiro; Murakami, Osamu; et al.
JAEA-Review 2025-035, 29 Pages, 2025/10
JAEA-Review-2025-035.pdf:1.12MB
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2025. The objectives and contents of this research are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
Cu and 
Cu with accelerator neutrons by deuterons and their separation from zincNagai, Yasuki*; Kawabata, Masako*; Saeki, Hideya*; Motoishi, Shoji*; Hashimoto, Kazuyuki; Tsukada, Kazuaki; Motomura, Arata*; Ota, Akio*; Takashima, Naoki*; Hashimoto, Shintaro; et al.
Frontiers in Nuclear Medicine (Internet), 5, p.1657125_1 - 1657125_11, 2025/10
In recent years, the radionuclide pair of Cu and Cu has attracted attention as an ideal theranostic agent. We proposed a novel production method utilizing a neutron source generated by deuteron beams at an accelerator facility. By irradiating enriched 
Zn samples with this neutron source, we measured the absolute activity and radionuclidic purity of the produced Cu. The results were consistent with calculations performed using PHITS and JENDL-5 developed by the Japan Atomic Energy Agency, confirming the reliability of the calculation method and demonstrating its capability to estimate the yields of trace radionuclides that are difficult to measure experimentally. Furthermore, we successfully separated Cu from the irradiated Zn sample using our developed sublimation and column separation techniques. These findings suggest that the production of Cu and Cu can be achieved in an economically sustainable manner at multiple sites.
Vauchy, R.; Horii, Yuta; Hirooka, Shun; Akashi, Masatoshi; Sunaoshi, Takeo*; Nakamichi, Shinya; Saito, Kosuke
Journal of Nuclear Materials, 616, p.156115_1 - 156115_16, 2025/10
Times Cited Count：1 Percentile：37.36(Materials Science, Multidisciplinary)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.
Takami, Kazusa*; Gomi, Yuibi*; Yasuda, Ryuichi*; Abe, Shinichiro; Ito, Masatoshi*; Kanda, Hiroki*; Fukuda, Mitsuhiro*; Hashimoto, Masanori*
IEEE Transactions on Nuclear Science, 72(8), p.2622 - 2628, 2025/08
Times Cited Count：4 Percentile：84.90(Engineering, Electrical & Electronic)Neutron-induced soft errors in the terrestrial environment pose reliability issues for semiconductor devices. We have developed the new method for estimating terrestrial SER based on simulation coupled with one-time irradiation using a conventional neutron source. This method has been validated using 65-nm planar SRAMs. However, with the ongoing progression of process shrinkage and the increasing adoption of devices fabricated with newer processes, there is a growing demand for further experimental validation of the terrestrial SER estimation method for these advanced processes. In this work, we validated the estimation method for 12-nm 1-fin FinFETs and 28-nm planer SRAMs. The SERs estimated by our method were consistent with the SERs measured using a white neutron beam at RCNP within 28% error.
/KNbO nanocomposite particlesYoneda, Yasuhiro; Kobayashi, Toru; Tsuji, Takuya; Shibata, Goro; Takeda, Yukiharu*; Saito, Yuji; Khanal, G. P.*; Fujii, Ichiro*; Ueno, Shintaro*; Sato, Yukio*; et al.
Japanese Journal of Applied Physics, 64(8), p.08SP07_1 - 08SP07_8, 2025/08
Times Cited Count：2 Percentile：21.19(Physics, Applied)It has become possible to synthesize high-quality composite nanoparticles in which a different material is grown on the surface of nanoparticle crystals. To evaluate such nanostructures, it is effective to combine different evaluation methods at various scales. We performed various structural and electronic state evaluations of BaTiO/KNbO nanocomposite particles using synchrotron radiation. From the structural evaluation, it was confirmed that the nanocomposite particles have a core of 100 nm of BaTiO covered with 20 nm of KNbO. The O-K absorption edge spectrum of the outermost surface KNbO was different from that of the bulk and nanoparticles, and it was found that the chemical bonding state changes when KNbO
is made into composite particles.
Yano, Yasuhide; Miyazawa, Takeshi; Tanno, Takashi; Akasaka, Naoaki; Yoshitake, Tsunemitsu; Kaito, Takeji; Otsuka, Satoshi
Journal of Nuclear Science and Technology, 62(8), p.748 - 755, 2025/08
Times Cited Count：2 Percentile：61.39(Nuclear Science & Technology)The effects of strain rate on tensile properties of irradiated modified 316 stainless steel (PNC316) claddings were investigated. PNC316 claddings were irradiated at the experimental fast reactor Joyo using CRT402 control rod assembly at 400
C up to 25 dpa. Post-irradiation ring tensile tests were carried out at strain rates of 3.310, 3.310
and 3.310
s
at a test temperature of 350C. The results showed no obvious dependence of all strain rates on tensile properties, although a slight decrease in total elongation was observed at the slowest strain rate of 3.310 s. In addition, only a part of fracture surface at the slowest strain rate showed intergranular type region in the inner surface area, although the grain boundary separation occurred on inner surfaces near the fracture region at all strain rates. It is suggested that presence of a high content of helium near the inner surfaces would be related to the fracture behavior.
Fe
O
Arisawa, Hiroki*; Fujimoto, Yuto*; Kikkawa, Takashi; Okamoto, Satoshi*; Umeda, Maki; Chudo, Hiroyuki; Saito, Eiji
Physical Review B, 111(21), p.214519_1 - 214519_5, 2025/06
Times Cited Count：3 Percentile：54.56(Materials Science, Multidisciplinary)Ito, Kengo*; Takahashi, Shin*; Kato, Chizu*; Fukutani, Satoshi*; Matsumura, Tatsuro; Fujii, Toshiyuki*
Journal of Radioanalytical and Nuclear Chemistry, 334, p.2467 - 2475, 2025/02
Times Cited Count：0 Percentile：0.00(Chemistry, Analytical)In this study, the solvent extraction behavior of tin (Sn), specifically 
Sn, from high-level radioactive waste was evaluated using six different extractants in a HNO system. Among the tested extractants, N,N-Didodecyl-2-hydroxyacetoamide (HAA) exhibited higher efficiency, still not sufficient for industrial implementation. In systems where HCl was added to HNO, both tributyl phosphate (TBP) and N,N,N,N'-tetra-2-ethylhexyl diglycolamide (TEHDGA) achieved D
values greater than 1 at 
1 M HCl. However, due to practical challenges in industrial applications, HAA extraction in HNO systems, particularly at low Sn concentrations (0.0008 M), may provide a more effective solution for Sn recovery.
Ito, Kengo*; Morita, Misaki*; Araki, Yuta*; Kato, Chizu*; Fukutani, Satoshi*; Matsumura, Tatsuro; Fujii, Toshiyuki*
Solvent Extraction Research and Development, Japan, 32(1), p.53 - 62, 2025/00
Times Cited Count：0 Percentile：0.00(Chemistry, Multidisciplinary)Rhodium (Rh) and Palladium (Pd) in high-level radioactive waste are primarily fission products. This Study focused on understanding the extraction behavior of these platinum group elements (PGEs) using the novel extractants 
-hexaoctylnitriloacetamide (HONTA) and alkyl diamideamine (ADAAM). Both extractants showed affinity for Pd, with distribution coefficients significantly exceeding 1, demonstrating their effectiveness in Pd separation. In contrast, the distribution coefficients for Rh were consistently below 10 , indicating low extraction efficiency from nitric acid. However, by leveraging the salting-out effect with calcium nitrate hydrate, a distribution coefficient of 
570 for Rh was achieved using HONTA. To overcome the difficult back-extraction of PGEs with HONTA, experiments were conducted using HEDTA and thiourea. Back-extraction with HEDTA in high-concentration nitric acid (2M) resulted in 90% extraction of Pd, while thiourea-based back-extraction with nitric acid yielded over 40% extraction for Rh, with the maximum of 62.7% achieved using hydrochloric acid.
