Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
白藤 雅也; 佐野 恭平; 堀内 雅一; 加藤 茜; 渡邉 一樹; 谷川 聖史; 丸山 創; 北尾 貴彦; Conner, J.*; LaFleur, A.*; et al.
第46回日本核物質管理学会年次大会会議論文集(インターネット), 4 Pages, 2025/12
The Japan Atomic Energy Agency, in collaboration with the U.S. Department of Energy and Los Alamos National Laboratory, initiated a joint research project to develop the Advanced Hulls Measurement and Monitoring System (A-HMMS) for quantifying trace amounts of nuclear material in hull drums. Monte Carlo simulations using the MCNP code confirmed that the presence of water significantly attenuates neutron count rates. However, sufficient sensitivity to plutonium mass variations was observed, indicating that measurements are feasible even with water present. Passive NDA methods based on the Cm/Pu ratio were found to be limited due to curium decay over long-term storage, necessitating the use of active interrogation techniques. Small-scale experiments validated the simulation results and demonstrated that waste type and source position significantly affect count rates, highlighting the need for waste-specific calibration curves. Full-scale testing is planned to evaluate system performance under realistic conditions and optimize the A-HMMS design.
大平 直也*; 樹神 克明; 伊藤 大介*; 齊藤 泰司*; Parker, J. D.*; 篠原 武尚
Nuclear Materials and Energy (Internet), 45, p.102005_1 - 102005_7, 2025/12
Lead-bismuth eutectic has emerged as a promising candidate for liquid metal coolant for Gen-IV nuclear reactors. Lead-bismuth eutectic is a unique material that expands gradually within the solid state. It may induce pipe deformation or rupture if it solidifies in a pipe or a container. In this study, the strain distributions of lead-bismuth eutectic in stainless-steel cups were evaluated using wavelength-resolved neutron imaging method. The wettability-improved case exhibited significantly larger compressive strain than in the others. The adhesion between lead-bismuth eutectic and the inner surface of the cup was a critical issue in the present study.
出井 俊太郎; 柴田 真仁*; 根岸 久美*; 杉浦 佑樹; 天野 由記; Bateman, K.*; Wilson, J.*; 横山 立憲; 鏡味 沙耶; 武田 匡樹; et al.
Results in Earth Sciences (Internet), 3, p.100097_1 - 100097_16, 2025/12
高レベル放射性廃棄物の地層処分において、セメントと泥岩の相互作用による化学的擾乱領域が形成され、岩盤中の核種移行特性に影響を及ぼす可能性がある。本研究では、11年前に幌延深地層研究センターの140m調査坑道に施工されたセメント(普通ポルトランドセメント(OPC)および低アルカリ性セメント(LAC))と泥岩の界面における変質状態について調査した。複数の分析手法を組み合わせることで、セメントの溶解、方解石やC-(A-)S-H相などの二次鉱物の析出、モンモリロナイトの陽イオン交換、泥岩の空隙率の低下など、セメントと岩石の界面における主要な反応が特定された。また、空隙率の低下による拡散の低下や、変質した泥岩中の二次鉱物への取り込みによる収着の促進など、セメントと泥岩の相互作用が放射性核種の移行に及ぼす影響についても明らかになった。
高橋 嘉夫*; 三浦 輝*; 山田 真也*; 関澤 央輝*; 新田 清文*; 橋本 直*; 蓬田 匠; 山口 瑛子; 岡田 信二*; 板井 啓明*; et al.
Journal of Hazardous Materials, 495, p.139031_1 - 139031_19, 2025/09
本発表では、2011年の福島第一原子力発電所事故で放出された放射性セシウム含有微粒子(CsMP)中のセシウムの化学状態を、高分解能X線吸収分光法(XANES)とマイクロX線蛍光(
-XRF)を用いて解析した。その結果、主にガラス中に溶解したセシウムと、内部空隙表面に濃縮したセシウムの2種が確認された。後者はもともと気体として存在し、溶けたガラスが冷えて固まる際に濃縮したと考えられる。これらの知見は、事故時のCsMP形成過程や今後の廃炉作業、安全評価に重要である。
Cm(
Ti,xn)
Og reaction cross sectionGall, B. J.-P.*; 浅井 雅人; 伊藤 由太; 豊嶋 厚史*; 他30名*
Journal of the Physical Society of Japan, 94(9), p.094201_1 - 094201_9, 2025/09
被引用回数：0 パーセンタイル：0.00TiビームをCm標的に照射してOg同位体を探索する実験を理化学研究所の仁科加速器科学研究センターにて実施した。準弾性後方散乱の励起関数から導出した準弾性散乱障壁分布より最適ビームエネルギーを決定した。実験の結果、Og同位体の崩壊は見つからず、1事象検出断面積として0.27pb、1
信頼度の断面積上限値として0.50pbの値を見積もることができた。
Karimi, V.*; Qvistgaard, C. H.*; Schmidt, S.*; Wolfertz, A.*; Parker, J. D.*; 甲斐 哲也; 林田 洋寿*; 篠原 武尚; Angelis, S. D.*; Tengattini, A.*; et al.
ACS Applied Materials & Interfaces, 17(36), p.50742 - 50752, 2025/08
被引用回数：0 パーセンタイル：0.00Anodic Ti-based porous transport layers (PTLs) are paramount for advancing high-efficiency proton exchange membrane water electrolyzers (PEMWEs). One of the major challenges with the development of PEMWE is the PTL/catalyst layer interface passivation, which is commonly alleviated by coating precious metals such as Pt. Herein, we report, for the first time, the usage of polarized neutron imaging (PNI) on a half-half PTL approach to investigate current distribution inside the PTL layer under the influence of Ti passivation under PEMWE operando condition. First, the electrochemical study of PEMWE reveals an obvious advantage of Pt coating in preventing Ti passivation by showing 822 mV less overpotential at 1 A cm
(1.771 V) for the superior sample (Pt-coated PTL) compared to the PEMWE with pristine Ti PTL (2.539 V). Second, it is confirmed that using ex situ electronic and structural characterizations, Ti passivation cannot be recognized, suggesting a temporary passivation process in an operating PEMWE. Employing PNI for operando mapping of the current distribution inside the PEMWE shows that most of the electrical current favors the Pt-coated PTL, perfectly aligned with the results obtained from the high-resolution operando neutron radiography in which around 60% of the produced oxygen was found in the Pt-coated PTL.
河合 優作*; Park, J.*; 元川 竜平; 以倉 崚平*; 村山 駿介*; 山岡 賢司*; 藤井 義久*; 池本 夕佳*; 田中 賢*; 松葉 豪*; et al.
ACS Applied Polymer Materials (Internet), 7(12), p.7767 - 7776, 2025/06
The material properties of polymeric materials in aqueous environments are significantly influenced by water content. It is widely recognized that polymeric materials become more brittle with increased water content. However, the specific relationship between hydration levels and polymer chains has not been fully elucidated, leaving many uncertainties. Conversely, intermediate water (IMW), which refers to adsorbed water, plays an active role in influencing the biocompatibility and antifouling properties of these materials. In this study, we examined the correlation between IMW and toughness (Gf) / Youngs modulus (E). We synthesized dual cross-network (DC) elastomers through the bulk copolymerization of cyclodextrin (CD) monomers and vinyl monomers in the presence of movable cross-linked elastomers. The resulting DC elastomers exhibited both high Gf and high E. We used poly(2-methoxyethyl acrylate) (PMEA) as the primary polymer and poly(N,N-dimethyl acrylamide) (PDMAA) as the secondary polymer. The DC materials were formulated as DC(MEA-DMAA)(100-w:w)(Wc), where w and Wc represent the weight percentage of the secondary polymer (PDMAA) and the water content, respectively. The mechanical properties of the DC materials mostly decreased with increasing amounts of the secondary polymer. However, DC(MEA-DMAA)(90:10)(22), which contained 10 wt percent of PDMAA, exhibited the highest Gf and E among all samples. Differential scanning calorimetry (DSC) measurements indicated the presence of IMW in DC(MEA-DMAA)(90:10)(22). We propose that the IMW in this sample facilitates the formation of crosslinks between polymer chains and water molecules, contributing to the observed enhancements in E and Gf.
青山 高士; Choudhary, S.*; Pandaleon, A.*; Burns, J. T.*; Kokaly, M.*; Restis, J.*; Ross, J.*; Kelly, R. G.*
Corrosion, 81(6), p.609 - 621, 2025/06
被引用回数：1 パーセンタイル：58.04(Materials Science, Multidisciplinary)This study presents a new test method for inducing controlled corrosion damage within simulated fastener holes of aluminum alloys, aimed at pretreating fatigue test specimens. The method involves insulating the outer surface while exposing the fastener hole surface to electrolytes containing 0.66 M NaCl + 0.1 M AlCl 
with varying concentrations of K 
S O 
. The evolution of corrosion damage within the fastener hole was examined as a function of exposure duration, electrolyte composition, and volume, as well as the effect of galvanic coupling with a SS316 cathode. Results indicate that fissure depth increases with an increase in K S O concentration but does not progress further after 24-48 hours of exposure in the chemical, or freely-corroding, exposure test. In contrast, galvanic coupling with a SS316 plate significantly accelerates corrosion, leading to much deeper fissures in a shorter time. The importance of electrolyte replenishment has been explored using electrochemical measurements, revealing the impact of evolving electrolyte chemistry. Beyond its application in fatigue specimen pretreatment, this method provides a simple yet effective approach for studying localized corrosion and evaluating mitigation strategies for fastener holes in aerospace structures.
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
被引用回数：0 パーセンタイル：58.65(Materials Science, Multidisciplinary)We study the magnetic properties of the metallic kagome system (FeCo)Sn by a combination of muon spin relaxation (SR), magnetic susceptibility, and scanning tunneling microscopy (STM) measurements in single crystal specimens with Co concentrations 
= 0, 0.11, 0.8. In the undoped antiferromagnetic compound FeSn, we find possible signatures for a previously unidentified phase that sets in at 
~K, well beneath the Neel temperature 
~K as indicated by a peak in the relaxation rate 1/
observed in zero field (ZF) and longitudinal field (LF) SR measurements, with a corresponding anomaly in the ac and dc susceptibility, and an increase in the static width 1/
in ZF-SR measurements. No signatures of spatial symmetry breaking are found in STM down to 7~K. Related to the location and motion of muons in FeSn, we confirmed a previous report that about 40% of the implanted muons reside at a field-cancelling high symmetry site at 
~K, while an onset of thermal hopping changes the site occupancy at higher temperatures. In Fe
Co
Sn, where disorder eliminated the field-cancellation effect, all the implanted muons exhibit precession and/or relaxation in the ordered state. In Fe
Co
Sn, we find canonical spin glass behavior with freezing temperature 
~K; the ZF and LF-SR time spectra exhibit results similar to those observed in dilute alloy spin glasses CuMn and AuFe, with a critical behavior of 
at 
and 
as 
. The absence of spin dynamics at low temperatures makes a clear contrast to the spin dynamics observed by SR in many geometrically frustrated spin systems on insulating kagome, pyrochlore, and triangular lattices. The spin glass behavior of CoSn doped with dilute Fe moments is shown to originate primarily from the randomness of doped Fe moments rather than due to geometrical frustration of the underlying lattice.
moleculePan, Y.-W.*; Lu, J.-X.*; 肥山 詠美子*; Geng, L.-S.*; 保坂 淳
Physical Review D, 111(11), p.114006_1 - 114006_9, 2025/06
ガウス展開法を使った三体計算によって分子に対する斥力三体力の影響を調べた結果を報告する。
Wilson, J.*; 笹本 広; 舘 幸男; 川間 大介*
Applied Clay Science, 275, p.107862_1 - 107862_15, 2025/05
被引用回数：0 パーセンタイル：70.79(Chemistry, Physical)高レベル放射性廃棄物の処分場では、鉄または鋼製ベースの容器/オーバーパック及びベントナイト緩衝材が用いられる。25年以上にわたり、鉄とベントナイトの相互作用に関わる研究が行われ、その中では、特に膨潤性粘土(スメクタイト)の鉄に富んだ層状珪酸塩(膨潤能が欠落する鉱物も存在)への変質可能性について検討がなされた。このような変質が生じると、人工バリア材の一つである緩衝材に期待されている膨潤性の欠落或いは低下を引き起こし、せん断応力に対するオーバーパックの保護性、水や溶質の移行抑制にも影響を与える。鉄とベントナイトの相互作用に関わるデータの多くは、実験及び地球化学モデリングによるものであり、ナチュラルアナログによるデータには乏しい。これらの既往データによれば、スメクタイト(アルミ質のモンモリロナイト)が鉄に富んだ固相(層状珪酸塩を含む)に変質したものや、グリーンラスト又は磁鉄鉱のような腐食生成物を伴う鉄に富んだ変質ゾーンが生成される可能性が示唆される。一方、このような変質ゾーンについての実態は複雑であり、現状での理解は不十分な部分もある。25年以上にもわたり研究が行われているにもかかわらず不確実な部分も多いが、今回のレビューにより、鉄とベントナイトの相互作用に伴い生じる尤もらしいシナリオが認識され、考えられ得る緩衝材特性への影響についても提示された。
加藤 優*; Zheng, J.*; Deng, Y.*; 斎藤 史恵*; 鵜沼 佑規*; 岡 紗雪*; 田村 和久; 八木 一三*
ACS Catalysis, 15(10), p.7710 - 7719, 2025/04
被引用回数：2 パーセンタイル：70.04(Chemistry, Physical)Nitrous oxide (NO) is a greenhouse and an ozone-depleting gas. Electrocatalytic NO reduction reaction (NORR) is known to be catalyzed at noble metal electrodes such as Pd and Pt, and the surface modification of such noble metals with Sn is known to increase the NORR in acidic media. However, the role of Sn at the surface remains unclear. In this work, NORR activity was investigated for single-crystalline Pt, Pd, and Pd-Pt electrodes with the (111) or (100) plane in the presence and absence of Sn at the electrode surface in acidic media. In situ X-ray crystal truncation rod (CTR) measurements of Sn-modified Pt(111) and Pd(111) electrodes revealed the presence of metallic Sn and SnO at their surfaces. The surface Sn modification enhances the NORR activity for Pd-Pt(100) or Pd(100) electrodes but not for the Pt(111), Pd-Pt(111), or Pt(100) electrodes.
hydridosilicate at high pressures; A Bridge to BaSiH
polyhydrideBeyer, D. C.*; Spektor, K.*; Vekilova, O. Y.*; Grins, J.*; Barros Brant Carvalho, P. H.*; Leinbach, L. J.*; Sannemo-Targama, M.*; Bhat, S.*; Baran, V.*; Etter, M.*; et al.
ACS Omega (Internet), 10(15), p.15029 - 15035, 2025/04
被引用回数：0 パーセンタイル：56.36(Chemistry, Multidisciplinary)SiH八面体部位を特徴とするヒドリドケイ酸塩は、水素貯蔵と水素化物イオン伝導に関連する潜在的な性質を持つかなり新しい化合物のクラスである。ここでは、Zintl相水素化物BaSiH
を4GPa以上の圧力でH
流体と反応させ、その後常圧まで減圧して得られた新しい代表的なBaSiHについて報告する。SiH
イオンはBa
対イオンによって八面体に配位している。Ba原子とSi原子の配置は理想的なfcc NaCl構造からわずかにずれている。IRとラマンスペクトルからSiHの屈曲と伸縮モードがそれぞれ800-1200と1400-1800cm
の範囲で観測された。BaSiHは95
Cまで熱的に安定であり、それ以上ではBaHとSiに分解する。DFT計算により、直接バンドギャップは2.5eVであることが示された。BaSiHの発見により、ギガパスカル圧力(10GPa以下)のシリサイドの水素化反応からアクセス可能なヒドリドケイ酸塩の化合物クラスが固まった。BaSiHの構造的性質は、超伝導ポリハイドライドBaSiHを予測されるより高い圧力で水素化するための中間体(あるいは前駆体)であることを示唆している。
Hu, F.-F.*; Qin, T.-Y.*; Ao, N.*; 徐 平光; Su, Y. H.; Parker, J. D.*; 篠原 武尚; 菖蒲 敬久; Kang, G.-Z.*; Ren, M.-M.; et al.
Journal of Traffic and Transportation Engineering, 25(2), p.75 - 93, 2025/04
To accurately predict the remaining lifetime of surface-strengthened railway axles, a damage tolerance method considering three-dimensional (3D) residual stresses was proposed. By taking the induction-hardened carbon steel S38C axle as an example, two-dimensional (2D) distribution characterization of residual strain and 3D residual stress measurement were performed through comprehensive application of the neutron Bragg-edge transmission imaging and angle-dispersive neutron diffraction experiments. A numerical method was employed to implant the 3D residual stress into the axle model, and the remaining lifetime of the full-scale axle was studied by coupling the measured load spectrum, press-fit loads, and residual stresses. Experimental results shows that, both axial and hoop directions present a compressive residual strain gradient layer of about 3 mm, with a maximum compressive residual strain of up to -4500 
in the surface layer, yet a maximum tensile strain of up to 1000 in the core. The maximum axial and hoop compressive stresses of the axle are about -500 MPa and -303 MPa respectively, while radial stresses overall fluctuate in the zero mean stress range. At depths beyond 4.5 mm from the surface layer, all three components are tensile stresses. The axle surface layer is subjected to compressive residual stresses, and crack propagation does not occur if the crack depth is less than 4.5 mm. Nevertheless, cracks propagate accelerates when the crack depth is greater than 4.5 mm. Different crack propagation depth thresholds lead to a larger calculated remaining lifetime for the residual stress-free condition than for the case where 3D residual stresses are taken into account. However, the axle remaining service mileage of the axle of 227000 Km under the most conservative conditions exceeds 3.5 non-destructive inspection (NDI) cycles, with a large safety margin. The experimental results can provide a scientific reference for the development and optimization of NDI cycles for surface-strengthened railway axles.
Md produced in the 
He + 
Es reaction西尾 勝久; 廣瀬 健太郎; 牧井 宏之; Orlandi, R.; Kean, K. R.*; 塚田 和明; 豊嶋 厚史*; 浅井 雅人; 佐藤 哲也; Chiera, N. M.*; et al.
Physical Review C, 111(4), p.044609_1 - 044609_12, 2025/04
被引用回数：0 パーセンタイル：70.48(Physics, Nuclear)In spontaneous fission (SF) it is found that the mass-asymmetric fission of well-known actinides suddenly changes to the symmetric fission when nucleus has a mass number 
larger than 257. We have measured for the first time fission-fragment mass and total-kinetic-energy (TKE) distributions of the excited compound nucleus Md, populated in the reaction He+Es, using the rare isotope Es with a short half-life, 
=276 days. The fission of Md can be interpreted as involving 3 fission modes: an mass-asymmetric mode and two modes of mass-asymmetric fissions, the latter two are manifested by different TKE values. Predominantly symmetric fission was obtained at the excitation energy of 15.0 MeV. By increasing the energy to 18.0 MeV, the asymmetric fission mode dominates. Both such a strong change of fission modes within a small increase of excitation energy and the enhancement of asymmetric split are new phenomena in fission.
rays in the 
La(
)
La reaction奥泉 舞桜*; Auton, C. J.*; 遠藤 駿典; 藤岡 宏之*; 広田 克也*; 猪野 隆*; 石崎 貢平*; 木村 敦; 北口 雅暁*; 古賀 淳*; et al.
Physical Review C, 111(3), p.034611_1 - 034611_6, 2025/03
被引用回数：0 パーセンタイル：70.48(Physics, Nuclear)The observed enhancement of Parity Violation in the vicinity of p-wave compound nuclear resonances for a variety of medium-heavy nuclei can be understood using the sp-mixing model. The sp-mixing model predicts several neutron energy-dependent angular correlations between the spin and momentum of neutron and -ray emitted from (n,) reactions. In this work, the correlation term 
in the La(
,)La
reaction was measured precisely and a significant transverse asymmetry was found in the transition to the excited states of La.
Lee, J.; Rossi, F.; 児玉 有; 弘中 浩太; 小泉 光生; 佐野 忠史*; 松尾 泰典*; 堀 順一*
Annals of Nuclear Energy, 211, p.111017_1 - 111017_7, 2025/02
被引用回数：0 パーセンタイル：0.00(Nuclear Science & Technology)Silica glass has been used as a base and host material in vitrified radioactive waste and lithium glass scintillator for neutron detection because of its superb transparency, high heat resistance, and excellent chemical inertness. Therefore, an accurate total cross section of the silica glass is important to evaluate the criticality safety for the vitrified wastes and to understand the neutron response for lithium glass scintillators accurately. In the present study, to provide the accurate total cross section in the thermal and epithermal energy range, the neutron transmission measurements were carried out by a pulsed neutron beam with the time-of-flight method at the Kyoto University Institute for Integrated Radiation and Nuclear Science - Linear Accelerator. We obtained the neutron total cross section of the silica glass in the energy region from 0.002 eV to 25 eV. The obtained results were compared and discussed with the previous results and the evaluated data.
Naeem, M.*; Ma, Y.*; Tian, J.*; Kong, H.*; Romero-Resendiz, L.*; Fan, Z.*; Jiang, F.*; Gong, W.; Harjo, S.; Wu, Z.*; et al.
Materials Science & Engineering A, 924, p.147819_1 - 147819_10, 2025/02
被引用回数：1 パーセンタイル：76.41(Nanoscience & Nanotechnology)Face-centered cubic (fcc) medium-/high-entropy alloys (M/HEAs) typically enhance strength and ductility at cryogenic temperatures via stacking faults, twinning, or martensitic transformation. However, in-situ neutron diffraction on VCoNi MEA at 15 K reveals that strain hardening is driven solely by rapid dislocation accumulation, without these mechanisms. This results in increased yield strength, strain hardening, and fracture strain. The behavior, explained by the Orowan equation, challenges conventional views on cryogenic strengthening in fcc M/HEAs and highlights the role of dislocation-mediated plasticity at low temperatures.
能崎 幸雄*; 介川 裕章*; 渡邉 紳一*; 柚木 清司*; 洞口 泰輔*; 中山 颯人*; 山野井 一人*; Wen, Z.*; He, C.*; Song, J.*; et al.
Science and Technology of Advanced Materials, 26(1), p.2428153_1 - 2428153_39, 2025/02
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)We present a novel method for generating spin currents using the gyromagnetic effect, a phenomenon discovered over a century ago. This effect, crucial for understanding the origins of magnetism, enables the coupling between various macroscopic rotational motions and electron spins. While higher rotational speeds intensify the effect, conventional mechanical rotations, typically, below 10,000 RPM, produce negligible results comparable to geomagnetic fluctuations, limiting applied research. Our studies demonstrate that spin current generation comparable to that of rare metals can be achieved through atomic rotations induced by GHz- range surface acoustic waves and the rotational motion of conduction electrons in metallic thin films with nanoscale gradient modulation of electrical conductivity. These effects, termed the acoustic gyromagnetic effect and the current-vorticity gyromagnetic effect, are significant in different contexts.
Metcalfe, R.*; Benbow, S. J.*; 川間 大介*; 舘 幸男
Science of the Total Environment, 958, p.177690_1 - 177690_17, 2025/01
花崗岩が隆起している条件を対象とした地層処分の安全評価においては、隆起による地質条件の変化とそれに伴う放射性核種の移行・遅延特性への影響を考慮する必要がある。このような地質環境の長期変遷を考慮した安全評価では、十分に現実的な数値モデルと適切なパラメータを適用する必要がある。しかしながら、隆起過程には、岩石特性や核種移行特性の変化などを含む複雑な連成現象が含まれるため、モデルの開発には困難を伴う。ここでは、いくつかの代表的な放射性核種を対象とした連成モデル解析を通じて、現実的で保守的なプロセスの概念化とモデルパラメータの設定を検討するための方法論を提示する。
