Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
齊藤 良佳*; 伊藤 尚美*; 阿部 暁樹*; 山本 知佳*; 松本 ちひろ*; Zhao, T.*; 森山 信彰*; 吉村 和也; 眞田 幸尚; 坪倉 正治*
Journal of Radiological Protection, 46(1), p.013502_1 - 013502_8, 2026/03
被引用回数：0 パーセンタイル：0.00(Environmental Sciences)This study reports Japan's implementation of a regulatory framework that enables limited, nonresidential land use in areas where radiation levels remain too high for repopulation following a nuclear accident, focusing on a wind power project in Katsurao Village, Fukushima Prefecture. Katsurao Village establised a multi-stakeholder committee; comprising residents, experts, government authorities, and industry representatives to evaluate dose-reduction measures, access protocols, environmental maintenance, and operational safeguards. The committee identified several unresolved issues, including the absence of standardized monitoring procedures, challenges in managing worker exposure, the need for clear demarcation and communication to prevent unauthorized entry, and mechanisms for transparent reporting in the event of abnormal findings. This case demonstrates both the feasibility and complexity of enabling controlled land use in high-dose areas, underscoring the importance of governance, technical standardization, and sustained risk communication.
藁科 友朗*; 佐藤 朝子*; 比内 浩; Shaikhutdinov, N.*; Shagimardanova, E.*; 森 宙史*; 玉木 聡志*; 斎藤 元文*; 眞田 幸尚; 佐々木 祥人; et al.
Applied and Environmental Microbiology, 90(4), p.e02113-23_1 - e02113-23_23, 2024/04
被引用回数：2 パーセンタイル：23.66(Biotechnology & Applied Microbiology)A major incident occurred at the Fukushima Daiichi Nuclear Power Station following the tsunami triggered by the Tohoku-Pacific Ocean Earthquake in March 2011, whereby seawater entered the torus room in the basement of the reactor building. Here, we identify and analyze the bacterial communities in the torus room water and several environmental samples. Samples of the torus room water (1 
10
Bq
Cs/L) were collected by the Tokyo Electric Power Company Holdings from two sampling points between 30 cm and 1 m from the bottom of the room (TW1) and the bottom layer (TW2). A structural analysis of the bacterial communities based on 16S rRNA amplicon sequencing revealed that the predominant bacterial genera in TW1 and TW2 were similar. TW1 primarily contained the genus Limnobacter, a thiosulfate-oxidizing bacterium. 
-Irradiation tests on Limnobacter thiooxidans, the most closely related phylogenetically found in TW1, indicated that its radiation resistance was similar to ordinary bacteria. TW2 predominantly contained the genus Brevirhabdus, a manganese- oxidizing bacterium. Although bacterial diversity in the torus room water was lower than seawater near Fukushima, 
70% of identified genera were associated with metal corrosion. Latent environment allocation - an analytical technique that estimates habitat distributions and co-detection analyses - revealed that the microbial communities in the torus room water originated from a distinct blend of natural marine microbial and artificial bacterial communities typical of biofilms, sludge, and wastewater. Understanding the specific bacteria linked to metal corrosion in damaged plants is important for advancing decommissioning efforts.
大島 宏之; 森下 正樹*; 相澤 康介; 安藤 勝訓; 芦田 貴志; 近澤 佳隆; 堂田 哲広; 江沼 康弘; 江連 俊樹; 深野 義隆; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
ナトリウム冷却高速炉(SFR: Sodium-cooled Fast Reactor)の歴史や、利点、課題を踏まえた安全性、設計、運用、メンテナンスなどについて解説する。AIを利用した設計手法など、SFRの実用化に向けた設計や研究開発についても述べる。
草野 完也*; 一本 潔*; 石井 守*; 三好 由純*; 余田 成男*; 秋吉 英治*; 浅井 歩*; 海老原 祐輔*; 藤原 均*; 後藤 忠徳*; et al.
Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12
被引用回数：7 パーセンタイル：29.80(Geosciences, Multidisciplinary)PSTEPとは、2015年4月から2020年3月まで日本国内の太陽・地球惑星圏に携わる研究者が協力して実施した科研費新学術領域研究である。この研究枠組みから500以上の査読付き論文が発表され、様々なセミナーやサマースクールが実施された。本論文では、その成果をまとめて報告する。
VAl/Fe layered films showing exchange bias窪田 崇秀*; 嶋田 雄介*; 土屋 朋生*; 吉川 智己*; 伊藤 啓太*; 竹田 幸治; 斎藤 祐児; 今野 豊彦*; 木村 昭夫*; 高梨 弘毅*
Nanomaterials (Internet), 11(7), p.1723_1 - 1723_11, 2021/07
被引用回数：3 パーセンタイル：12.95(Chemistry, Multidisciplinary)Heusler alloys exhibit various magnetic properties. In this study, a layered sample consisting of a Heusler alloy, MnVAl and a ferromagnet, Fe, is selected as a material system exhibiting exchange bias. Although the fully ordered MnVAl is known as a ferrimagnet, the MnVAl/Fe layered structure exhibits exchange bias. The high-angle annular dark field STEM images demonstrated the formation of MnVAl clusters with the L2
phase distributed only around the interface to the Fe layer in the sample. Furthermore, the antiferromagnetic coupling between the Mn- and Fe-moments were observed in element specific hysteresis loops measured using XMCD. The locally ordered L2 phase and antiferromagnetic Mn-moments in the MnVAl layer are important for the exchange bias.
MnGe (Ga) film via Ge (Ga) 
absorption spectroscopy吉川 智己*; Antonov, V. N.*; 河野 嵩*; 鹿子木 将明*; 角田 一樹; 宮本 幸治*; 竹田 幸治; 斎藤 祐児; 後藤 一希*; 桜庭 裕弥*; et al.
Physical Review B, 102(6), p.064428_1 - 064428_7, 2020/08
被引用回数：3 パーセンタイル：12.46(Materials Science, Multidisciplinary)X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) spectroscopy were applied at the Ge (Ga) edge to unravel the spin-resolved unoccupied electronic states of CoMnGe (Ga). Complicated spectral features were observed in both XAS and XMCD spectra. For their interpretation, we compared the experimental XAS and XMCD spectra with the calculated Ge (Ga) 4
and 4
orbital partial density of states. The comparison enabled a qualitative explanation of the XMCD spectra as the difference between the majority and minority-spin unoccupied density of states summed over the 4 and 4 orbitals. Our finding provides a new approach to uncover the spin-split partial density of states above the Fermi level.
MnGe revealed by resonant photoelectron spectroscopy河野 嵩*; 鹿子木 将明*; 吉川 智己*; Wang, X.*; 角田 一樹*; 宮本 幸治*; 室 隆桂之*; 竹田 幸治; 斎藤 祐児; 後藤 一希*; et al.
Physical Review B, 100(16), p.165120_1 - 165120_6, 2019/10
被引用回数：7 パーセンタイル：27.73(Materials Science, Multidisciplinary)Resonant photoelectron spectroscopy at the Co and Mn 2
core absorption edges of half-metallic CoMnGe has been performed to determine the element-specific density of states (DOS). A significant contribution of the Mn 3
partial DOS near the Fermi level (
) was clarified by measurement at the Mn 2 absorption edge. Further analysis by first-principles calculation revealed that it has 
symmetry, which must be responsible for the electrical conductivity along the line perpendicular to the film plane. The dominant normal Auger contribution observed at the Co 2 absorption edge indicates delocalization of photoexcited Co 3 electrons. The difference in the degrees of localization of the Mn 3 and Co 3 electrons in CoMnGe is explained by the first-principles calculation.
Shikin, A. M.*; Estyunin, D. A.*; Surnin, Yu. I.*; Koroleva, A. V.*; Shevchenko, E. V.*; Kokh, K. A.*; Tereshchenko, O. E.*; Kumar, S.*; Schwier, E. F.*; 島田 賢也*; et al.
Scientific Reports (Internet), 9, p.4813_1 - 4813_17, 2019/03
被引用回数：22 パーセンタイル：63.35(Multidisciplinary Sciences)A new kind of magnetically-doped antiferromagnetic (AFM) topological insulators (TIs), Bi
Gd
Sb
Te
, has been studied by angle-resolved photoemission, superconducting magnetometry (SQUID) and X-ray magnetic circular dichroism (XMCD). It has been shown that this TI is characterized by the Dirac gap at the Fermi level. In the paramagnetic phase, a surface magnetic layer is supposed to develop, where the coupling between the Gd magnetic moments is mediated by the topological surface states (TSSs). This assumption can be confirmed by opening a gap at the Dirac point indicated by the surface-sensitive ARPES, a weak hysteresis loop measured by SQUID, the XMCD showing a surface magnetic moment and the temperature dependence of electrical resistance demonstrating a mid-gap semiconducting behavior, which correlates with the temperature dependence of the surface magnetization and confirms the conclusion that only TSSs are located at the Fermi level.
Sn strand during cooling諏訪 友音*; 辺見 努*; 齊藤 徹*; 高橋 良和*; 小泉 徳潔*; Luzin, V.*; 鈴木 裕士; Harjo, S.
IEEE Transactions on Applied Superconductivity, 28(3), p.6001104_1 - 6001104_4, 2018/04
被引用回数：1 パーセンタイル：6.32(Engineering, Electrical & Electronic)NbSn strands, whose properties are very sensitive to stress/strain, are utilized for ITER cable-in-conduit conductor (CICC) of the central solenoids. The NbSn strands experience temperature range of 1000 K from the temperature of the heat treatment with the initiation of the NbSn reaction to the operation temperature of 4 K. Due to this large temperature range, large thermal strain is induced in the NbSn filaments due to the differences between the coefficients of thermal expansion and Young's moduli of the components of the strand. Therefore, it is considered that initial performance of the CICC is influenced by the thermal strain on the NbSn, and it is important to evaluate the strain state of the NbSn strand at low temperature. In this study, the thermal strain of the components of free NbSn strand was measured by neutron diffraction and stress/strain state was assessed from room temperature to low temperature. As the results of diffraction measurements, it was found that 0.111 % and 0.209 % compressive strain were generated in NbSn filaments at 300 and 10 K, respectively.
小林 大眞*; 吉川 智英*; 松尾 衛*; 井口 亮*; 前川 禎通; 齊藤 英治; 能崎 幸雄*
Physical Review Letters, 119(7), p.077202_1 - 077202_5, 2017/08
被引用回数：161 パーセンタイル：97.61(Physics, Multidisciplinary)We demonstrate the generation of alternating spin current (SC) via spin-rotation coupling (SRC) using a surface acoustic wave (SAW) in a Cu film. Ferromagnetic resonance caused by injecting SAWs was observed in a Ni-Fe film attached to a Cu film, with the resonance further found to be suppressed through the insertion of a SiO film into the interface. The intensity of the resonance depended on the angle between the wave vector of the SAW and the magnetization of the Ni-Fe film. This angular dependence is explicable in terms of the presence of spin transfer torque from a SC generated via SRC.
尾関 秀将; 齊藤 徹; 河野 勝己; 高橋 良和; 布谷 嘉彦; 山崎 亨; 礒野 高明
Physics Procedia, 67, p.1010 - 1015, 2015/07
被引用回数：6 パーセンタイル：81.33(Physics, Applied)JAEA is responsible for procurement of the central solenoid (CS) conductor for ITER. The CS conductor is assembled by inserting NbSn superconductor cable into circular-in-square jacket whose material is JK2LB high manganese stainless steel developed by JAEA, and then heat treatment is carried out. In the recent study of NbSn strand, heat treatment for 250 hours at 570 degrees Celsius and 100 hours at 650 degrees is adopted. The effect of 250 hours at 570 degree for JK2LB has not studied yet although the region of 650 degree has already studied, and might be a cause of sensitization. So the characteristics of JK2LB jacket after heat treatment for 250 hours at 570 degree and then 200 hours at 650 degree was studied in terms of mechanical tests at 4K and metallographic tests. The mechanical test results satisfied the requirement of ITER and metallographic tests result showed no remarkable degradation. This study proved JK2LB jacket can be applicable to the heat treatment above.
尾関 秀将; 礒野 高明; 河野 勝己; 齊藤 徹; 川崎 勉; 西野 克巳; 奥野 清; 木戸 修一*; 仙波 智行*; 鈴木 洋三*; et al.
IEEE Transactions on Applied Superconductivity, 25(3), p.4200804_1 - 4200804_4, 2015/06
被引用回数：0 パーセンタイル：0.00(Engineering, Electrical & Electronic)JAEA is planning performance test of 50 m Toroidal Field (TF) conductor of ITER using Central Solenoid Model Coil (CSMC) test facility at Naka-site in Japan. In order to test the conductor, "TF Insert Coil" (TFIC) is under fabrication in cooperate with Hitachi, Ltd. TFIC is a solenoid coil wound in 1.44 m diameter. It is going to be installed into the bore of CSMC, whose maximum magnetic field is 13 T. The maximum driven current of TFIC is 68 kA. In order to prepare for fabrication of TFIC, several trials of components including windings, removal of Cr plating of the strands, welding and compaction of terminal sleeve were carried out for process qualification. The results of trials showed that the winding dimater satisfied its criterion, the Cr plating was clearly removed using non-woven cloth soaked into HCl solution, the mechanical strengths at 4 K of welds at the terminal were enough. Eventually, the fabrication process qualification of TFIC was completed.
ions observed using high-resolution Rutherford backscattering spectroscopy中嶋 薫*; 森田 陽亮*; 北山 巧*; 鈴木 基史*; 鳴海 一雅; 齋藤 勇一; 辻本 将彦*; 磯田 正二*; 藤居 義和*; 木村 健二*
Nuclear Instruments and Methods in Physics Research B, 332, p.117 - 121, 2014/08
被引用回数：7 パーセンタイル：43.61(Instruments & Instrumentation)Our previous observation that an impact of sub-MeV C ion makes an ion track in a thin amorphous silicon nitride (a-SiN) film suggests emission of thousands of atoms from the cylindrical region. Sputtering yields of a-SiN films by C ions were evaluated in order to confirm this observation. A-SiN films deposited on Si(001) were irradiated with 540-keV C ions at fluences from 2.510
to 110
ions/cm
. The compositional depth profiles of the irradiated samples were measured with high-resolution Rutherford backscattering spectroscopy, and the sputtering yields were estimated at 3900 
500 N atoms/ion and 1500 1000 Si atoms/ion. The sputtering yield of N was two orders of magnitude larger than the elastic sputtering yield by the SRIM code or than the measured electronic sputtering yield of a-SiN by 50-MeV Cu ions previously reported. Such a large sputtering yield cannot be explained either by the elastic sputtering or by the electronic sputtering. However, an estimation of the synergistic effect based on the inelastic thermal spike model roughly explains the observed large sputtering yield, indicating that the synergistic effect of the nuclear and electronic stopping powers plays an important role.
尾関 秀将; 濱田 一弥; 高橋 良和; 布谷 嘉彦; 河野 勝己; 押切 雅幸; 齊藤 徹; 手島 修*; 松並 正寛*
IEEE Transactions on Applied Superconductivity, 24(3), p.4800604_1 - 4800604_4, 2014/06
被引用回数：18 パーセンタイル：62.03(Engineering, Electrical & Electronic)JAEA is in charge of procuring Center Solenoid (CS) conductor in ITER project. CS conductor is Cable-In-Conduit type, and conduit is also called jacket. The cross-sectional shape of CS jacket is circle-in-square type, whose outer dimension is 51.3 mm and inner diameter is 35.3 mm. The length of one CS jacket section is 7 m, and the necessary total length of CS conductor is about 43 km. CS coil is expected to suffer high electro-magnetic force, so JAEA developed JK2LB, which is modified stainless steel expected to better characteristics of fatigue and thermal contraction in 4 K than SUS316LN, in cooperate with Kobe Steel, Ltd. The remaining problem was to establish production process of jackets which satisfy dimensional and mechanical requirement in ITER consistently, and also, Non-Destructive Examination (NDE) by ITER-original criteria. To carry out the R&D for above, production of dummy CS jackets were executed and these jackets were fabricated successfully. The results are reported.
駒 義和; 芦田 敬; 目黒 義弘; 宮本 泰明; 佐々木 紀樹; 山岸 功; 亀尾 裕; 寺田 敦彦; 檜山 敏明; 小山 智造; et al.
Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.736 - 743, 2013/09
東京電力福島第一原子力発電所の事故に伴い発生した廃棄物の管理に関して、原子力機構が進めている研究開発の成果を概観する。
長尾 誠也*; 新堀 雄一*; 田中 忠夫; 佐々木 隆之*; 斉藤 拓巳*; 桐島 陽*; 吉川 英樹; 飯島 和毅; 濱 克宏; 岩月 輝希; et al.
原子力バックエンド研究(CD-ROM), 20(1), p.3 - 14, 2013/06
本研究は、放射性廃棄物の地層処分における国内の地下水コロイドの影響評価研究の現状について各研究機関での研究を紹介し、実質的なネットワーク化と性能評価におけるコロイド影響の取り扱い方等について、今後の研究の方向性に関する提案を取りまとめた。具体的には、地下水コロイドの特性、地下環境における真性コロイドや擬似コロイドの移行挙動、国内における地下水コロイド研究の取り組み、コロイド評価の体系化、フィールド調査と実験室研究の連携、研究ネットワーク構築の必要性などについて解説するとともに、コロイド研究を展開するにあたって専門家が共有化しておくべき方向性を示した。
濱田 一弥; 布谷 嘉彦; 礒野 高明; 高橋 良和; 河野 勝己; 齊藤 徹; 押切 雅幸; 宇野 康弘; 小泉 徳潔; 中嶋 秀夫; et al.
IEEE Transactions on Applied Superconductivity, 22(3), p.4203404_1 - 4203404_4, 2012/06
被引用回数：18 パーセンタイル：63.13(Engineering, Electrical & Electronic)ITER計画において、原子力機構は、日本のITER国内機関として、中心ソレノイド導体の調達を担当している。CS導体は、外形49mm角,内径32.6mmの矩形円管(ジャケット)に直径0.8mmのNbSn超伝導素線576本と銅線288本を束ねたケーブルを挿入した構造である。ジャケット材料には日本が開発した高マンガンステンレス鋼であるJK2LBを使用する。導体は、(1)51.3mm角,長さ7mのジャケットを溶接接続して900mの直線管を製作し、(2)ケーブルを引き込み,(3)外形を49mm角に圧縮成形(コンパクション)しながら直径4mに仮巻きして製作する。仮巻きされた導体は、米国に送付され、中心ソレノイドコイルに仕上げられてITERに組み込まれる。導体製作を開始する準備作業として、(1)ジャケット機械試験,(2)溶接材料選定のための溶接試験,(3)100mのケーブルを用いた滑り摩擦係数の測定,(4)コンパクション及び巻き取り後の断面変形特性試験、を実施した。これらのR&Dにより、中心ソレノイド導体の調達開始のための製作技術を確認でき、調達準備が整った。
濱田 一弥; 高橋 良和; 名原 啓博; 河野 勝己; 海老澤 昇; 押切 雅幸; 堤 史明; 斎藤 徹*; 中嶋 秀夫; 松田 英光*; et al.
低温工学, 47(3), p.153 - 159, 2012/03
日本原子力研究開発機構は、ITER計画における日本の国内機関として、トロイダル磁場コイル用超伝導導体33本の製作を担当している。導体は、直径0.8mmのNbSn超伝導素線900本,銅線522本を撚合せて、直径43.7mm,肉厚2mmのステンレス保護管(ジャケット)に収めた構造であり、長さは430m及び760mである。導体の製作は2008年から開始され、2009年12月に導体製作装置を完成させた。超伝導導体の製作開始に先立ち、760mの銅製のダミー撚線を用いて模擬導体を製作し、製作方法が適切であることを実証し、実機導体の製作に着手した。導体製作のための技術として、原子力機構のこれまでの機械特性データを元に、TF導体用ジャケット材料用の改良型SUS316LN鋼やITERが要求する微小欠陥の検出技術も開発した。ジャケットの溶接部の品質管理については部分ヘリウムリーク試験技術及び溶接部内面形状寸法測定技術を開発した。これらを含めて日本が一連の導体製作技術を各極に先駆けて確立し、ジャケットに関しては他極が製作するTF導体においても採用された。
studied by photoemission and soft X-ray absorption spectroscopies内海 有希*; 佐藤 仁*; 栗原 秀直*; 間曽 寛之*; 平岡 耕一*; 小島 健一*; 飛松 浩明*; 大河内 拓雄*; 藤森 伸一; 竹田 幸治; et al.
Physical Review B, 84(11), p.115143_1 - 115143_7, 2011/09
被引用回数：13 パーセンタイル：46.62(Materials Science, Multidisciplinary)典型的な価数揺動系であるYbInCuの価電子状態を、硬X線内殻光電子分光,軟X線吸収実験、及び軟X線光電子分光の温度依存性の実験から研究した。YbInCuの価数転移について、価電子帯からYb 4
状態への電荷移動で記述した。
川口 和弘; 齋藤 正裕*; 高廣 克己*; 山本 春也; 吉川 正人
Plasmonics, 6(3), p.535 - 539, 2011/09
被引用回数：9 パーセンタイル：29.06(Chemistry, Physical)銀ナノ粒子の表面にガス分子が吸着し粒子近傍の誘電率が変化すると、銀ナノ粒子の局在型表面プラズモン共鳴(LSPR)によって生じる可視光領域の吸収ピークが変化する。この現象を漏洩ガスの光学的検知に応用し、ガスセンサーを作製しようとする試みが行われているが、センサー材料として応用するには、安定したLSPRを発現する銀ナノ粒子を再現性よく作製する技術が必要となる。このため銀ナノ粒子を着床させた透明基板を試料とし、作製手法と得られる吸収ピークの強度や位置との関連性が研究されているが、理論値と異なることが多く、その原因はよくわかっていない。筆者らは、銀ナノ粒子作製時に表面に付着するさまざまな付着物がその原因であると推定し、作製した銀ナノ粒子に表面洗浄法として知られているプラズマ処理を行い、吸収ピークの位置や強度の変化を調べた。その結果、プラズマ処理後吸収ピークの幅が狭くなり短波長側へとシフトして理論値に近づく傾向が認められた。さらに、プラズマ処理で銀ナノ粒子表面の炭素系付着物が減少することがラマン散乱分析からわかり、吸収ピークの実験値と理論値の違いは、銀ナノ粒子表面の炭素系付着物に影響することが示唆された。
