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櫻井 惇也*; 鳥形 啓輔*; 松永 学*; 高梨 直人*; 日比野 真也*; 木津 健一*; 森田 聡*; 井元 雅弘*; 下畠 伸朗*; 豊田 晃大; et al.
鉄と鋼, 111(5), p.246 - 262, 2025/04
Creep testing is time-consuming and costly, leading institutions to limit the number of tests conducted to the minimum necessary for their specific objectives. By pooling data from each institution, it is anticipated that predictive models can be developed for a wide range of materials, including welded joints and degraded materials exposed to service conditions. However, the data obtained by each institution is often highly confidential, making it challenging to share with others. Federated learning, a type of privacy-preserving computation technology, allows for learning while keeping data confidential. Utilizing this approach, it is possible to develop creep life prediction models by leveraging data from various institutions. In this paper, we constructed global deep neural network models for predicting creep rupture life of heat-resistant ferritic steels in collaboration with eight institutions using the federated learning system we developed for this purpose. Each institution built a local model using only its own data for comparison. While these local models demonstrated good predictive accuracy for their respective datasets, their predictive performance declined when applied to data from other institutions. In contrast, the global model constructed using federated learning showed reasonably good predictive performance across all institutions. The distance between each institution's data was defined in the space of explanatory variables, with the NIMS data, which had the largest dataset, serving as the reference point. The global model maintained high predictive accuracy regardless of the distance from the NIMS data, whereas the predictive accuracy of the NIMS local model significantly decreased as the distance increased.
Rajeev, H. S.*; Hu, X.*; Chen, W.-L.*; Zhang, D.*; Chen, T.*; 古府 麻衣子*; 梶本 亮一; 中村 充孝; Chen, A. Z.*; Johnson, G. C.*; et al.
Journal of the Physical Society of Japan, 94(3), p.034602_1 - 034602_14, 2025/03
被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)Two-dimensional hybrid organic-inorganic perovskites (HOIPs) have emerged as promising materials for light-emitting diode applications. In this study, by using time-of-flight neutron spectroscopy we identified and quantitatively separated the lattice vibrational and molecular rotational dynamics of two perovskites, butylammonium lead iodide (BA)
PbI
and phenethyl-ammonium lead iodide (PEA)PbI. By examining the corresponding temperature dependence, we found that the lattice vibrations, as evidenced by neutron spectra, are consistent with the lattice dynamics obtained from Raman scattering. We revealed that the rotational dynamics of organic molecules in these materials tend to suppress their photoluminescence quantum yield (PLQY) while the vibrational dynamics did not show predominant correlations with the same. Additionally, we observed photoluminescence emission peak splitting for both systems, which becomes prominent above certain critical temperatures where the suppression of PLQY begins. This study suggests that the rotational motions of polarized molecules may lead to a reduction in exciton binding energy or the breaking of degeneracy in exciton binding energy levels, enhancing non-radiative recombination rates, and consequently reducing photoluminescence yield. These findings offer a deeper understanding of fundamental interactions in 2D HOIPs and could guide the design of more efficient light-emitting materials for advanced technological applications.
Sb
with a honeycomb network足立 匡*; Ogawa, Taiki*; 小宮山 陽太*; 須村 拓也*; Saito-Tsuboi, Yuki*; Takeuchi, Takaaki*; Mano, Kohei*; Manabe, Kaoru*; 川端 幸樹*; 今津 毅士*; et al.
Physical Review B, 111(10), p.L100508_1 - L100508_6, 2025/03
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)Chiral superconductivity exhibits the formation of novel electron pairs that breaks the time-reversal symmetry and has been actively studied in various quantum materials in recent years. However, despite its potential to provide definitive information, effects of disorder in the crystal structure on the chiral superconductivity has not yet been clarified, and therefore the investigation using a solid-solution system is desirable. We report muon-spin-relaxation (
SR) results of layered pnictide BaPtAsSb with a honeycomb network composed of Pt and (As, Sb). We observed an increase of the zero-field SR rate in the superconducting (SC) state at the Sb end of 
, suggesting the occurrence of a spontaneous magnetic field due to the time-reversal symmetry breaking in the SC state. On the other hand, a spontaneous magnetic field was almost and completely suppressed for the As-Sb mixed samples of 
and 0.2, respectively, suggesting that the time-reversal symmetry-breaking SC state in is sensitive to disorder. The magnetic penetration depth estimated from transverse-field SR measurements at and 0.2 behaved like weak-coupling 
-wave superconductivity. These seemingly incompatible zero-field and transverse-field SR results of BaPtAsSb with could be understood in terms of chiral 
-wave superconductivity with point nodes on the three-dimensional Fermi surface.
谷川 聖史; 瀬谷 和仁*; 浅川 直也*; 林 宏幸*; 堀籠 和志; 向 泰宣; 北尾 貴彦; 中村 仁宣; Henzlova, D.*; Swinhoe, M. T.*; et al.
JAEA-Technology 2024-014, 63 Pages, 2025/02
JAEA-Technology-2024-014.pdf:3.02MB
プルトニウム転換技術開発施設の廃液処理工程で発生したスラッジ中のPu量を評価する上で、スラッジは生成上、多くの不純物(Na, Fe, Ni等)を含み不均質であるため、従来の破壊分析ではサンプリングによる代表性が乏しく、Pu量測定に係る測定不確かさが大きかった(約24%)。この測定不確かさを低減させるために、日本原子力研究開発機構と米国ロスアラモス国立研究所は共同で中性子を利用した非破壊測定装置のPlutonium Scrap Multiplicity Counter (PSMC)を用いた測定技術の開発を進めた。MOX粉末を用いた模擬スラッジやモンテカルロ法により検証等を行いPSMC検出器パラメーター(predelay, doubles gatefraction等)を最適化し、高分解能ガンマ線分光分析を組み合わせて測定した結果、含有不純物の影響はないことが確認でき、従来法と比べ新たに設定した非破壊測定方法における測定不確かさは約6.5%まで低減できた。さらに、PSMC測定値の妥当性を評価するため、IAEA立ち合いの下、ガンマ線を測定しPu量を評価するIn Situ Object Counting System (ISOCS)を用いた比較測定した結果、ISOCSとPSMCの測定値は両方の測定不確かさの範囲内で一致したため、PSMCによる測定値の妥当性が確認された。これらの結果より、本非破壊測定技術はスラッジのように不純物を多く含み、サンプリングの代表性が乏しいアイテムに有効であり、スラッジの計量管理に適用することが認められた。
Sm synchrotron-radiation-based M
ssbauer spectroscopy of Sm-based heavy fermion compounds筒井 智嗣; 東中 隆二*; 水牧 仁一朗*; 小林 義男*; 中村 仁*; 伊藤 孝; 依田 芳卓*; 松田 達磨*; 青木 勇二*; 佐藤 英行*
Interactions (Internet), 245(1), p.9_1 - 9_10, 2024/12
Sm synchrotron-radiation-based Mssbauer spectroscopy has been applied to Sm-based heavy fermion intermetallics, Sm
Al
(
= Ti, V and Cr) and SmOsSb
. The isomer shifts obtained demonstrate that the Sm valence states in these compounds are intermediate. Since the difference of the isomer shifts in 22.502 keV Sm Mssbauer effect between Sm
and Sm
state is comparable to the 2nd order Doppler shift, consideration of the 2nd order Doppler shift is required to precisely discuss Sm valence state through the shifts of the Mssbauer spectra. In addition, the plots of the isomer shifts obtained by the Mssbauer spectroscopy against the Sm valence states estimated from Sm L-edge X-ray absorption spectroscopy exhibit a linear correlation except for that in SmOs
Sb. This implies that the origin of the intermediate valence state in SmOsSb differs from that in SmAl ( = Ti, V and Cr).
Sm synchrotron-radiation-based Mssbauer and 
SR studies of Sm
RuGe
筒井 智嗣; 伊藤 孝; 中村 仁*; 吉田 実生*; 小林 義男*; 依田 芳卓*; 中村 惇平*; 幸田 章宏*; 東中 隆二*; 青木 大*; et al.
Interactions (Internet), 245(1), p.55_1 - 55_9, 2024/12
Sm SR-based Mssbauer and muon spin relaxation (SR) spectroscopies have been applied to SmRuGe. The temperature dependence of the Sm SR-based Mssbauer spectra in the paramagnetic state implies the presence of dynamical nuclear Zeeman and/or quadrupole interactions. The time differential SR spectra also exhibit a marked temperature dependence in the paramagnetic state, indicating the presence of magnetic fluctuation in SmRuGe at least. These results in the present work infer that the dynamical hyperfine interactions observed using the mutually complementary spectroscopic methods are connected with the mechanism of the heavy fermion behavior in SmRuGe.
下村 浩一郎*; 幸田 章宏*; Pant, A. D.*; 砂川 光*; 藤森 寛*; 梅垣 いづみ*; 中村 惇平*; 藤原 理賀; 反保 元伸*; 河村 成肇*; et al.
Interactions (Internet), 245(1), p.31_1 - 31_6, 2024/12
J-PARC Muon Facility: MUSE (Muon Science Establishment) is responsible for the inter-university user program and the operation, maintenance, and construction of the muon beamlines, namely D-line, S-line, U-line, and H-line, along with the muon source at J-PARC Materials and Life Science Facility (MLF). In this paper, recent developments are briefly presented.
藤澤 唯太*; Krishnadas, A*; Nakamura, Tomonori*; Hsu, C.-H.*; Smith, B. R. M.*; Pardo-Almanza, M*; Hiyane, Hoshu*; 永井 佑紀; 町田 理*; 岡田 佳憲*
Physical Review B, 110(22), p.224511_1 - 224511_5, 2024/12
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)エキゾチックな超伝導体の超伝導磁束の振る舞いを明らかにすることは、今後のデバイス開発にとって重要である。超伝導体LiTiO(111)の薄膜を作製し、磁場中での電子状態を走査型トンネル顕微鏡によって観測した。その際、接合部分の曲率に応じて超伝導磁束の状態が大きく変化することがわかった。そして、その変化は理論計算によっても確かめられた。この結果は、Josephson磁束を実験的な構造変化によってコントロールできる可能性を示唆しており、今後の新たなデバイス開発において重要な結果となるだろう。
小手川 恒*; 中村 彰良*; Huyen, V. T. N.*; 新井 祐樹*; 藤 秀樹*; 菅原 仁*; 林 純一*; 武田 圭生*; 田端 千紘; 金子 耕士; et al.
Physical Review B, 110(21), p.214417_1 - 214417_8, 2024/12
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)In this study, we show that the orthorhombic system TaMnP exhibits a large anomalous Hall conductivity (AHC) in spite of the small net magnetization. Neutron scattering experiment and the observation of the AH effect comprehensively suggest a dominant AF structure in TaMnP is represented by 
. The AHC is one of the largest among those observed in AF materials at zero fields. First-principles calculations suggest that the spin-orbit interaction originating in nonmagnetic Ta-5 electrons significantly contributes to the enhancement of Berry curvatures in the momentum space. We found that the AF domain switching is triggered by the magnetic fields along all the crystal axes. This indicates that the AF domain determining the sign of the Hall response can be controlled even through the small net magnetization symmetrically different.
石川 諒尚; 田中 浩基*; 中村 哲志*; 熊田 博明*; 櫻井 良憲*; 渡辺 賢一*; 吉橋 幸子*; 棚上 裕生*; 瓜谷 章*; 鬼柳 善明*
Journal of Radiation Research (Internet), 65(6), p.765 - 775, 2024/11
被引用回数：0 パーセンタイル：0.00(Biology)From the viewpoints of the advantage depths (ADs), peak tumor dose, and skin dose, we evaluated the effect of neutron beam properties, namely, the ratio between thermal and epithermal neutron fluxes (thermal/epithermal ratio), fast neutron component, and 
-ray component on the dose distribution. Several parameter surveys were conducted with respect to the beam properties of neutron sources for boron neutron capture therapy assuming boronophenylalanine as the boron agent using our dose calculation tool, called SiDE. The ADs decreased by 3% at a thermal/epithermal ratio of 20% - 30% compared with the current recommendation of 
. The skin dose increased with the increasing thermal/epithermal ratio, reaching a restricted value of 14 Gy-eq at a thermal/epithermal ratio of 
. The fast neutron component was modified using two different models, namely, the "linear model," in which the fast neutron intensity decreases log-linearly with the increasing neutron energy, and the "moderator thickness (MT) model," in which the fast neutron component is varied by adjusting the moderator thickness in a virtual beam shaping assembly. Although a higher fast neutron component indicated a higher skin dose, the increment was 
at a fast neutron component of 
Gy cm
for both models. Furthermore, in the MT model, the epithermal neutron intensity was 
higher at a fast neutron component of 
Gy cm compared with the current recommendation of 
Gy cm. The -ray component also caused no significant disadvantages up to several times larger compared with the current recommendation.
吉田 剛*; 松村 宏*; 中村 一*; 三浦 太一*; 豊田 晃弘*; 桝本 和義*; 中林 貴之*; 松田 誠
Journal of Nuclear Science and Technology, 61(10), p.1298 - 1307, 2024/10
被引用回数：0 パーセンタイル：0.00(Nuclear Science & Technology)The activation level of the JAEA-Tokai tandem accelerator facility was investigated experimentally in advance of the future decommissioning. JAEA-Tokai tandem accelerator facility has a higher terminal voltage of 18 MV and a larger total floor area, Compared to other electrostatic accelerators with terminal voltage of 1 MV to 6 MV. Therefore, determination for 'where', 'what', and 'how many' nuclides are produced in the facility is crucial. Thermal neutrons generated by beam losses associated with accelerator operations contribute significantly to the activation of equipment and facilities. The accumulated activities of 
Co and 
Eu; the most considerable radionuclides at the decommissioning, can be deduced by the thermal neutron fluence rate during the accelerator operation. In this study, thermal neutron fluence measurement on the surface of the pressure vessel and concrete building was conducted with conventional methods using dosimeters and metal foil detectors as well as a new method using a portable -ray detector. The thermal neutron fluence in the facility during the accelerator operation ranges from 101 to 10
n/cm
/s. The sum of deduced activities of Co and Eu in 50 years is much lower than the clearance level of 0.1 Bq/g in all areas except in the irradiation room.
曽我部 丞司; 石田 真也; 田上 浩孝; 岡野 靖; 神山 健司; 小野田 雄一; 松場 賢一; 山野 秀将; 久保 重信; 久保田 龍三郎*; et al.
Proceedings of International Conference on Nuclear Fuel Cycle (GLOBAL2024) (Internet), 4 Pages, 2024/10
日仏協力の枠組みにおいて、タンク型ナトリウム冷却高速を対象とした過酷事故の評価手法を定義し、解析評価を実施した。
中島 多朗*; 齋藤 開*; 小林 尚暉*; 川崎 卓郎; 中村 龍也; 古川 はづき*; 浅井 晋一郎*; 益田 隆嗣*
Journal of the Physical Society of Japan, 93(9), p.091002_1 - 091002_5, 2024/09
被引用回数：2 パーセンタイル：64.46(Physics, Multidisciplinary)Neutron scattering is a powerful tool to study magnetic structures and cross-correlated phenomena originated from symmetry of the magnetic structures in matter. Among a number of neutron scattering techniques, polarized neutron scattering is quite sensitive to the orientations of the magnetic moments, which are essential to understand microscopic mechanisms of the spin-driven emergent phenomena. Here, we present POlarized Neutron Triple-Axis spectrometer PONTA in the Japan Research Reactor 3 (JRR-3), and show the present capabilities of polarized and unpolarized neutron scattering by introducing recent results from the instrument.
遠藤 駿典; 安部 亮太*; 藤岡 宏之*; 猪野 隆*; 岩本 修; 岩本 信之; 河村 しほり*; 木村 敦; 北口 雅暁*; 小林 龍珠*; et al.
European Physical Journal A, 60(8), p.166_1 - 166_10, 2024/08
被引用回数：2 パーセンタイル：74.11(Physics, Nuclear)Measurements of -ray circular polarization emitted from neutron capture reactions provide valuable information for nuclear physics studies. The spin and parity of excited states can be determined by measuring the circular polarization from polarized neutron capture reactions. Furthermore, the -ray circular polarization in a neutron capture resonance is crucial for studying the enhancement effect of parity nonconservation in compound nuclei. The -ray circular polarization can be measured using a polarimeter based on magnetic Compton scattering. A polarimeter was constructed, and its performance indicators were evaluated using a circularly polarized -ray beam. Furthermore, as a demonstration, the -ray circular polarization was measured in 
S(n,)
S reactions with polarized neutrons.
二宮 和彦*; 大澤 崇人; 寺田 健太郎*; 和田 大雅*; 長澤 俊作*; Chiu, I.-H.; 中村 智樹*; 他40名*
Meteoritics & Planetary Science, 59(8), p.2044 - 2057, 2024/08
被引用回数：2 パーセンタイル：64.73(Geochemistry & Geophysics)小惑星探査機「はやぶさ」2が持ち帰った小惑星リュウグウのサンプルは、太陽系の起源と進化を調べる上で重要である。ここでは、非破壊ミュオン元素分析法を用いて測定した123mgのリュウグウ試料の元素組成を報告する。3種類の炭素質コンドライトを用いたミュオンX線スペクトルから、元素組成とミュオンX線強度の関係を各元素について求めた。検量線は直線性を示し、リュウグウの元素組成は定量的に決定された。リュウグウの元素組成は、サンプル数が多いため、小惑星リュウグウの平均的なバルク元素組成を反映している。リュウグウの元素組成はオルグイユ(CI1)と類似しており、CI1に分類されるべきである。しかし、リュウグウのO/Si比はオルグイユのO/Si比より25%低く、オルグイユが地球に落下した後、地球物質によって深刻に汚染された可能性を示している。これらの結果は、リュウグウ試料が太陽系の固体物質としてCIコンドライトよりも代表的であることを示している。
山野 秀将; 高井 俊秀; 江村 優軌; 福山 博之*; 東 英生*; 西 剛史*; 守田 幸路*; 中村 勤也*; Ahmed, Z.*; Pellegrini, M.*
Proceedings of 14th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation, and Safety (NTHOS-14) (Internet), 12 Pages, 2024/08
本発表はプロジェクト全体概要及び2022年度までの進捗概要について報告する。この論文における具体的成果は、初めての固化試験データを取得したことである。
石塚 悦男; 長住 達; 長谷川 俊成; 川井 大海*; 脇坂 真司*; 長瀬 颯太*; 中村 建斗*; 矢口 陽樹*; 石井 俊晃; 中野 優美*; et al.
JAEA-Technology 2024-008, 23 Pages, 2024/07
JAEA-Technology-2024-008.pdf:1.69MB
「HTTRに関する技術開発」をテーマとした2023年度夏期休暇実習において、3つの大学から5名が参加した。参加者は、HTTR炉心の解析、強制冷却機能喪失時の挙動解析、一次冷却系統のヨウ素沈着挙動解析、高温ガス炉用エネルギー貯蔵システムの概念検討について実習した。実習後のアンケートでは、就業体験として有益であったこと、一部の学生においては自身の研究に役立ったこと等の感想があり、本実習は概ね良好な評価を得た。
中村 いずみ*; 滝藤 聖崇; 嶋津 龍弥*; 奥田 幸彦; 酒井 理哉*; 大谷 章仁*; 渡壁 智祥; 奥田 貴大; 渋谷 忠弘*; 白鳥 正樹*
Proceedings of ASME 2024 Pressure Vessels & Piping Conference (PVP 2024) (Internet), 9 Pages, 2024/07
A new seismic design procedure which evaluates the inelastic behavior of piping system by detailed finite element method (FEM) analysis has been developed in Japan (the JSME CC); however, the inelastic behavior is only considered for pipe body in the JSME CC, and the evaluation of inelastic behavior of pipe support structure is still not included. To clarify the current analytical accuracy of inelastic analysis of pipe support structures and to develop an analytical guideline to reasonably include the inelastic behavior of pipe support structure in the seismic design of piping system, a series of benchmark analysis on pipe support structures has been launched in 2022. The benchmark analysis of pipe support structures consists of mainly two stages; the first stage is the analysis of pipe support structures themselves, and the second stage is the analysis of piping system with inelastic support structure. As of January 2024, the first stage of benchmark analysis is in progress. It is confirmed that there are some variabilities in modeling of support structures, stress-strain relationship, and boundary conditions. The load-deflection relationships also show variability even when the support structures are in the elastic region. The effect of these variations to the response of piping system model is remained as future tasks.
谷川 聖史; 中村 大司; 浅川 直也*; 瀬谷 和仁*; 大森 二美男*; 小磯 勝也*; 堀籠 和志; 清水 靖之
JAEA-Technology 2024-001, 37 Pages, 2024/05
JAEA-Technology-2024-001.pdf:2.32MB
プルトニウム転換技術開発施設の廃液処理工程で発生した中和沈殿焙焼体及び凝集沈殿焙焼体(スラッジ)については、ポリ容器に収納し梱包用のビニルバッグで密封して、各々中和沈殿焙焼体はグローブボックスに、凝集沈殿焙焼体は施設内の保管場所に保管している。これらスラッジは、保管中においてスラッジ中に含有する水分等が放射性元素由来の
線等により放射線分解されて発生するガスにより、梱包するビニルバッグの膨らみが確認されていた。このため、1983年の操業開始以降、スラッジを梱包したビニルバッグの膨らみを定期的に確認し、膨らみを確認したものはビニルバッグの交換を行うことで、安全に保管管理を実施してきた。スラッジからの放射線分解によるガスの発生を防止し、保管時の安全性を向上させるために、ガスの発生原因となっているスラッジ中の吸湿性のある硝酸ナトリウム塩を取り除く安定化処理作業を2018年8月から開始し、2022年8月まで実施した。その安定化処理としてスラッジの水洗浄処理を実施した結果、スラッジ中に含まれるナトリウム濃度を3wt%以下まで低減することができた。また、そのスラッジは1年以上にわたって各々の保管場所で保管していた際に、保管に使用している梱包用のビニルバッグに膨らみがなく、かつガスの発生原因となるスラッジの含水率に増加は認められないことを確認したことから、保管中の安全性が向上していること及び今後、放射線分解によるガスの発生はないものと評価した。安定性が確認できた中和沈殿焙焼体は、粉末缶に収納し粉末貯蔵エリアに保管廃棄した。これにより、中和沈殿焙焼体及び凝集沈殿焙焼体において、内部からのガスの発生によるリスクがなくなり、保管時の安全性を向上することができた。
Baccou, J.*; Glantz, T.*; Ghione, A.*; Sargentini, L.*; Fillion, P.*; Damblin, G.*; Sueur, R.*; Iooss, B.*; Fang, J.*; Liu, J.*; et al.
Nuclear Engineering and Design, 421, p.113035_1 - 113035_16, 2024/05
被引用回数：6 パーセンタイル：96.49(Nuclear Science & Technology)In the Best-Estimate Plus Uncertainty (BEPU) framework, the use of best-estimate code requires to go through a Verification, Validation and Uncertainty Quantification process (VVUQ). The relevance of the experimental data in relation to the physical phenomena of interest in the VVUQ process is crucial. Adequacy analysis of selected experimental databases addresses this problem. The outcomes of the analysis can be used to select a subset of relevant experimental data, to encourage designing new experiments or to drop some experiments from a database because of their substantial lack of adequacy. The development of a specific transparent and reproducible approach to analyze the relevance of experimental data for VVUQ still remains open and is the topic of this contribution. In this paper, the concept of adequacy initially introduced in the OECD/NEA SAPIUM (Systematic APproach for model Input Uncertainty quantification Methodology) activity is formalized. It is defined through two key properties, called representativeness and completeness, that allows considering the multifactorial dimension of the adequacy problem. A new systematic approach is then proposed to analyze the adequacy of a set of experimental databases. It relies on the introduction of two sets of criteria to characterize representativeness and completeness and on the use of multi-criteria decision analysis method to perform the analysis. Finally, the approach is applied in the framework of the new OECD/NEA ATRIUM activity which includes a set of practical IUQ exercises in thermal-hydraulics to test the SAPIUM guideline in determining input uncertainties and forward propagating them on an application case. It allows evaluating the adequacy of eight experimental databases coming from the Super Moby-dick, Sozzi-Sutherland and Marviken experiments and identifying the most adequate ones.
