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Conformation, hydration, and ligand exchange process of ruthenium nitrosyl complexes in aqueous solution; Free-energy calculations by a combination of molecular-orbital theories and different solvent models

城戸 健太朗; 金子 政志

Journal of Computational Chemistry, 44(4), p.546 - 558, 2023/02

 被引用回数:0 パーセンタイル:0(Chemistry, Multidisciplinary)

Distribution of solvent molecules near transition-metal complex is key information to comprehend the functionality, reactivity and so on. However, polarizable continuum solvent models still are the standard and conventional partner of molecular-orbital (MO) calculations in the solution system including transition-metal complex. In this study, we investigate the conformation, hydration structure and ligand substitution reaction between NO$$_2^-$$ and H$$_2$$O in aqueous solution for [Ru(NO)(OH)(NO$$_2$$)$$_4$$]$$^{2-}$$ (${bf A}$), [Ru(NO)(OH)(NO$$_2$$)$$_3$$(ONO)]$$^{2-}$$ (${bf B}$) and [Ru(NO)(OH)(NO$$_2$$)$$_3$$(H$$_2$$O)]$$^-$$ (${bf C}$) using a combination method of MO theories and a state-of-the-art molecular solvation technique (NI-MC-MOZ-SCF). In the complexes, the treatment is essentially required because except for nitrosyl ligand, a strong hydrogen bond is formed between the ligand and solvent water. These results are complementary to the data previously obtained by $$^{15}$$N NMR experiment. A dominant species is found in the complex ${bf B}$ conformers and, as expected, different between the solvent models, which reveals that molecular solvation beyond continuum media treatment are required for a reliable description of solvation near transition-metal complex. In the stability constant evaluation of ligand substitution reaction, similar to the previous reports, an assumption that considers the direct association between the dissociated nitrite anion and complex ${bf C}$ is useful to obtain a reliable stability constant.


New material exploration to enhance neutron intensity below cold neutrons; Nanosized graphene flower aggregation

勅使河原 誠; 池田 裕二郎*; Yan, M.*; 村松 一生*; 須谷 康一*; 福住 正文*; 能田 洋平*; 小泉 智*; 猿田 晃一; 大竹 淑恵*

Nanomaterials (Internet), 13(1), p.76_1 - 76_9, 2023/01

 被引用回数:0 パーセンタイル:0.05(Chemistry, Multidisciplinary)



Characterization of bremsstrahlung and $$gamma$$-rays of fuel debris

松村 太伊知; 奥村 啓介; 藤田 学*; 坂本 雅洋; 寺島 顕一; Riyana, E. S.

Radiation Physics and Chemistry, 199, p.110298_1 - 110298_8, 2022/10

 被引用回数:0 パーセンタイル:0.01(Chemistry, Physical)

The characterization of bremsstrahlung and $$gamma$$-rays from fuel debris differs from that of spent fuels evaluated to date, due to factors such as material composition and release of volatile fission products. In this work, in order to clarify the conditions under which the effect of bremsstrahlung compared to the total photons (bremsstrahlung and $$gamma$$-rays) in fuel debris is maximized, the average energies and dose rates from the energy spectra of bremsstrahlung and $$gamma$$-rays on the fuel debris surface were obtained using a Monte Carlo simulation. In the simulation, the average energies and dose rates were evaluated with consideration of the composition, size, fission product release, and retrieval time of the fuel debris. The simulation showed that the composition with the largest amount of change to the average total photons energy caused by bremsstrahlung was the molten fuel debris, and the composition with the maximum fraction of bremsstrahlung in the dose rate was the UO$$_{2}$$. The maximum value of the fraction of bremsstrahlung in the dose rate was evaluated to be about 17%. This work is expected to contribute to the prediction of the radiation characteristics of the fuel debris that will be retrieved from the Fukushima Daiichi Nuclear Power Station in the near future.


Experimental and numerical study on energy separation in vortex tube with a hollow helical fin (Joint research)

呉田 昌俊; 山形 洋司*; 宮腰 賢*; 増井 達也*; 三浦 義明*; 高橋 一憲*

JAEA-Research 2022-007, 28 Pages, 2022/09




The Multiaxial creep-fatigue failure mechanism of Mod. 9Cr-1Mo steel under non-proportional loading; Effect of strain energy on failure lives

小川 文男*; 中山 雄太*; 旭吉 雅健*; 橋立 竜太; 若井 隆純; 伊藤 隆基*

Transactions of the Indian National Academy of Engineering (Internet), 7(2), p.549 - 564, 2022/06



A Theoretical investigation on the intermolecular potential curve between ruthenium tetroxide and NO$$_{rm X}$$ (X = 1, 2)

城戸 健太朗

International Journal of Quantum Chemistry, 121(21), p.e26781_1 - e26781_15, 2021/11

 被引用回数:1 パーセンタイル:30.58(Chemistry, Physical)

Ruthenium tetroxide (RuO$$_4$$) is one of chemical species of fission products assumed to be released to the environment during a severe accident of nuclear facilities and a target compound to assess the amount produced, reactivity, mobility and release timing. In this article, the NO$$_{rm X}$$ (X = 1, 2) adduct formation of RuO$$_4$$ has been investigated, based on the potential energy curve (PEC) evaluated by UM06, UTPSSh, CASSCF, and CASPT2 methods. At several stationary points, CCSD and LR-CCSD(T) energies are also computed for a comparison. The PEC shows that there is an activation barrier to form the NO$$_{rm X}$$ adduct and that the process is endothermic in terms of free energy. In the system, the electron transfer occurs from NO$$_{rm X}$$ to RuO$$_4$$ when the bond between the nitrogen and oxo ligand is formed. It has been discussed in detail using active orbitals, weight of electron configurations and spin population obtained by CASSCF.



菖蒲 敬久; 城 鮎美*; 村松 壽晴*

SPring-8/SACLA利用研究成果集(インターネット), 9(5), p.318 - 323, 2021/08



Development of a membrane reactor with a closed-end silica membrane for nuclear-heated hydrogen production

Myagmarjav, O.; 田中 伸幸; 野村 幹弘*; 野口 弘喜; 今井 良行; 上地 優; 久保 真治; 竹上 弘彰

Progress in Nuclear Energy, 137, p.103772_1 - 103772_7, 2021/07

 被引用回数:5 パーセンタイル:84.68(Nuclear Science & Technology)

Hydrogen production from nuclear energy has attracted considerable interest as a clean energy solution to address the challenges of climate change and environmental sustainability. With respect to the large-scale and economical production of hydrogen using nuclear energy, the thermochemical water-splitting iodine-sulfur (IS) process is a promising method. The IS process uses sulfur and iodine compounds to decompose water into its elemental constituents, hydrogen and oxygen, by using three coupled chemical reactions: the Bunsen reaction; sulfuric acid decomposition; and hydrogen iodide (HI) decomposition. The decomposition of HI is the efficiency-determining step of the process. In this work, a membrane reactor with a silica membrane closed on one end was designed, and its potential for hydrogen production from HI decomposition was explored. In the reactor-module design, only one end of the membrane tube was fixed, while the closed-end of the tube was freely suspended to avoid thermal expansion effects. The closed-end silica membranes were prepared for the first time by a counter-diffusion chemical vapor deposition of hexyltrimethoxysilane. In application, HI conversion of greater than 0.60 was achieved at a decomposition temperature of 400$$^{circ}$$C. Thus, the membrane reactor with closed-end silica membrane was shown to produce a successful equilibrium shift in the production of hydrogen via HI decomposition in the thermochemical IS process.


Visualization of the boron distribution in core material melting and relocation specimen by neutron energy resolving method

阿部 雄太; 土川 雄介; 甲斐 哲也; 松本 吉弘*; Parker, J. D.*; 篠原 武尚; 大石 佑治*; 加美山 隆*; 永江 勇二; 佐藤 一憲

JPS Conference Proceedings (Internet), 33, p.011075_1 - 011075_6, 2021/03

Since the hardness of fuel debris containing boride from B$$_{4}$$C pellet in control rod is estimated to be two times higher as that of oxide, such as UO$$_{2}$$ and ZrO$$_{2}$$, distribution of such boride in the fuel debris formed in the Fukushima-Daiichi Nuclear Power Plants may affect the process of debris cutting and removal. The high neutron absorption of boron may affect the possibility of re-criticality during the process of debris removal. Therefore, boride distribution in fuel debris is regarded as an important issue to be addressed. However, boron tends to have difficult in quantification with conventionally applied methods like EPMA and XPS. In this study, accelerator-driven neutron-imaging system was applied. Since boron is the material for neutron absorption, its sensitivity in terms of neutron penetration through specimens is concerned. To adjust neutron attenuation of a specimen to suit a particular measurement by selecting the neutron energy range, we focused on the energy resolved neutron imaging system RADEN, which utilizes wide energy range from meV to keV. Development of a method to visualize boron distribution using energy-resolved neutrons has been started. In this presentation the authors show the status of the development of a method utilizing energy-resolved neutrons and provide some outcome from its application to the Core Material Melting and Relocation (CMMR)-0 and -2 specimens.



奥野 浩; 山本 一也

JAEA-Review 2020-066, 32 Pages, 2021/02


国際原子力機関(International Atomic Energy Agency、略称: IAEA)は、アジア原子力安全ネットワーク(Asian Nuclear Safety Network、略称: ANSN)の活動を2002年から実施している。その一環としてANSNの下に原子力あるいは放射線災害を対象とする平時の備えと緊急時への対応に関するグループ(Topical Group on Emergency Preparedness and Response、略称: EPRTG)を2006年に設立した。EPRTGの提案に基づきIAEAは2006年から2017年までの12年間に23件のアジア地域ワークショップを実施した。緊急時対応に関するテーマ分野には、原子力防災訓練,緊急時医療,原子力・放射線緊急事態後の長期的対応,国際協力,国の原子力防災体制整備などがあった。日本原子力研究開発機構は、RPRTG設立当初からコーディネータを輩出し、その活動を主導してきた。本報告書は、EPRTGの提案に基づきIAEAが2017年までに実施したアジア地域ワークショップの概要をまとめたものである。


Phase-field model for crystallization in alkali disilicate glasses; Li$$_2$$O-2SiO$$_2$$, Na$$_2$$O-2SiO$$_2$$ and K$$_2$$O-2SiO$$_2$$

河口 宗道; 宇埜 正美*

Journal of the Ceramic Society of Japan, 128(10), p.832 - 838, 2020/10

 被引用回数:1 パーセンタイル:0.01(Materials Science, Ceramics)

本研究では、移動度係数($$L$$)を新しく定義することで、溶融酸化物系におけるフェーズフィールド法(PFM)の技術を開発した。一定の移動係数$$L$$を用いたPFM計算から得られた結晶成長速度($$v_0$$)は、normal growthモデルの熱力学的推進力と同程度であった。また$$L$$の温度依存性は、実験から得られた結晶成長速度と$$v_0$$から決定し、その決定した$$L$$を使って、二酸化アルカリケイ酸ガラスのLi$$_2$$O-2SiO$$_2$$, Na$$_2$$O-2SiO$$_2$$, K$$_2$$O-2SiO$$_2$$の結晶成長速度($$v$$)をシミュレーションした。$$v$$の温度依存性は定性的および定量的に非常に良く一致したため、本PFM計算は$$L$$の有効性を実証した。特に、PFM計算によって得られた$$v$$は、融点($$T_{rm m}$$)で増大し、$$T_{rm m}$$-100Kでピークを示した。さらなる温度の下降では、$$v$$は明確に0ms$$^-1$$に近づくことが分かった。この振舞いは、界面のジャンプ過程を表現する$$L$$によって$$v$$が制限されているためである。$$L$$のパラメータ$$B$$の感度についてもPFM計算を行い、$$B$$$$0$$から$$2$$まで増加すると、$$v$$のピークはより急峻に、ピーク温度は高温側にシフトすることが分かった。アルカリ金属の原子番号が増加するにつれてイオンポテンシャルは減少するので、$$L$$のパラメータ$$A$$$$B$$は、それぞれ指数関数的に増加、直線的に減少することになったと考えられる。本計算により$$L$$$$A$$$$B$$は互いに密接な関係であることが分かった。



外川 織彦; 早川 剛; 田中 忠夫; 山本 一也; 奥野 浩

JAEA-Review 2020-017, 36 Pages, 2020/09


我が国は、原子力事故または放射線緊急事態に際して、国際的支援の提供に貢献するため、2010年に国際原子力機関(IAEA)の緊急時対応援助ネットワーク(RANET)に参加した。その際に、日本原子力研究開発機構(JAEA: 原子力機構)は現地外での技術援助が可能な機関としてRANETに登録した。原子力機構の登録分野は以下の7分野であった。すなわち、(1)航空機による汚染調査、(2)放射線レベル・汚染調査、(3)環境試料の濃度測定、(4)事故評価と助言、(5)体内被ばく線量評価、(6)バイオアッセイ、(7)線量再構築であった。登録後に原子力機構は援助可能性の問合せを3回受けたが、実際に援助を行うには至らなかった。一方、RANET登録に関連してIAEAが実施する国際緊急時対応演習(ConvEx)にほぼ毎年参加してきた。本報告書では、RANETの概要、原子力機構の登録及びConvEx参加活動の概要を述べる。


A Cubic CeBr$$_{3}$$ gamma-ray spectrometer suitable for the decommissioning of the Fukushima Daiichi Nuclear Power Station

冠城 雅晃; 島添 健次*; 大鷹 豊*; 上ノ町 水紀*; 鎌田 圭*; Kim, K. J.*; 吉野 将生*; 庄子 育宏*; 吉川 彰*; 高橋 浩之*; et al.

Nuclear Instruments and Methods in Physics Research A, 971, p.164118_1 - 164118_8, 2020/08

 被引用回数:6 パーセンタイル:73.86(Instruments & Instrumentation)

Our work focused on the passive gamma-ray analysis (PGA) of the nuclear fuel debris based on measuring gamma rays with an energy greater than 1 MeV for the decommissioning of the Fukushima Daiichi Nuclear Power Station (FDNPS). The PGA requires gamma-ray spectrometers to be used under the high dose rates in the FDNPS, then we fabricated a small cubic CeBr$$_{3}$$ spectrometer with dimensions of 5 mm $$times$$ 5 mm $$times$$ 5 mm, coupled to a Hamamatsu R7600U-200 photomultiplier tube (PMT). The performance at dose rates of 4.4 to 750 mSv/h in a $$^{60}$$Co field was investigated. The energy resolution (FWHM) at 1333 keV ranged from 3.79% to 4.01%, with a standard deviation of 6.9%, which met the narrow gamma decay spectral lines between $$^{154}$$Eu (1274 keV) and $$^{60}$$Co (1333 keV). However, the spectra shifted to a higher energy level as the dose rate increase, there was a 51% increase at the dose rates of 4.4 to 750 mSv/h, which was caused by the PMT gain increase.


Development of three-dimensional distribution visualization technology for boron using energy resolved neutron-imaging system (RADEN)

阿部 雄太; 土川 雄介; 甲斐 哲也; 松本 吉弘*; Parker, J. D.*; 篠原 武尚; 大石 佑治*; 加美山 隆*; 永江 勇二; 佐藤 一憲

Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 6 Pages, 2020/08

Boron carbide is used as a neutron-absorbing material in Fukushima-Daiichi Nuclear Power Station (1F), producing borides that are twice as hard as oxides (such as UO$$_{2}$$ and ZrO$$_{2}$$). The high neutron absorption of boron affects the evaluation of re-criticality during the process of debris retrieval. Therefore, it is important not only to determine the presence of boron but also to investigate the distribution of boron inside the material in a non-destructive manner during decommissioning. To address the uncertainties in the core material relocation behavior of boiling water reactor (BWR) during a severe accident (SA), solidified melt specimens of a simulated fuel assembly were prepared by plasma heating. If core material melting and relocation (CMMR) specimens can be used to estimate the B distribution in 1F Unit-3, that will provide valuable information in the decommissioning of 1F. To address this, the authors focused on the energy-resolved neutron imaging system, RADEN, which utilizes a wide energy range, from meV to keV. This is an innovative three-dimensional analysis technology for boride distribution that affects the evaluation of hardness and re-criticality. In the calibration standard samples (Zr$$_{x}$$B$$_{1-x}$$ and Fe$$_{x}$$B$$_{1-x}$$), there was a good correlation between boron concentration and the energy-dependence of the cross sections of cold and epi-thermal neutrons. In the CMMR specimens, boron distribution was confirmed from the contrast difference between cold and epi-thermal neutrons. In the future, the results of calibration standard samples will be applied to the results of CMMR specimens. With this method, three-dimensional boron distribution will be measured, and the understanding of boride distribution 1F Unit-3 will be improved, which may be reflected in an improved SA code.


企画セッション(「シグマ」特別専門委員会主催、核データ部会共催)「シグマ」特別専門委員会2017、2018年度活動報告,4; 「シグマ」調査専門委員会の活動予定

深堀 智生

核データニュース(インターネット), (125), p.20 - 25, 2020/02



Evaluation of energy spectrum around structural materials in radiation environments

松村 太伊知; 永石 隆二; 片倉 純一*; 鈴木 雅秀*

Radiation Physics and Chemistry, 166, p.108493_1 - 108493_9, 2020/01

 被引用回数:1 パーセンタイル:17.77(Chemistry, Physical)



The Analysis of thermomechanical periodic motions of a drinking bird

上地 俊*; 上地 宏*; 西村 昭彦

World Journal of Engineering and Technology, 7(4), p.559 - 571, 2019/11



A Noniterative mean-field QM/MM-type approach with a linear response approximation toward an efficient free-energy evaluation

城戸 健太朗

Journal of Computational Chemistry, 40(24), p.2072 - 2085, 2019/09

 被引用回数:2 パーセンタイル:11.25(Chemistry, Multidisciplinary)

Mean-field treatment of solvent provides an efficient technique to investigate chemical processes in solution in QM/MM framework. In the algorithm, an iterative calculation is required to obtain the self-consistency between QM and MM regions, which is a time-consuming step. In the present study, we have proposed a non-iterative approach by introducing a linear response approximation (LRA) into the solvation term in the one-electron part of Fock matrix in a hybrid approach between MO calculations and a three-dimensional integral equation theory for molecular liquids (MC-MOZ-SCF; Kido $textit{et al.}$, J. Chem. Phys. $textbf{143}$, 014103 (2015)). To save the computational time, we have also developed a fast method to generate electrostatic potential map near solute and the solvation term in Fock matrix, using Fourier transformation (FT) and real spherical harmonics expansion (RSHE). To numerically validate the LRA and FT-RSHE method, we applied the present approach to water, carbonic acid and their ionic species in aqueous solution. Molecular properties of the solutes were evaluated by the present approach with four different types of initial wave function and compared with those by the original (MC-MOZ-SCF). From the averaged speed up ratio, the present approach is 13.5 times faster than MC-MOZ-SCF.


Measurement of neutron scattering cross section of nano-diamond with particle diameter of approximately 5 nm in energy range of 0.2 meV to 100 meV

勅使河原 誠; 土川 雄介*; 市川 豪*; 高田 慎一; 三島 賢二*; 原田 正英; 大井 元貴; 河村 幸彦*; 甲斐 哲也; 河村 聖子; et al.

Nuclear Instruments and Methods in Physics Research A, 929, p.113 - 120, 2019/06

 被引用回数:13 パーセンタイル:84.78(Instruments & Instrumentation)

ナノダイアモンドは、冷中性子以下のエネルギーにおける反射材として注目されている。ナノダイアモンドを用いた中性子源の高度化には、断面積データの整備が必要である。そのため、この論文では、中性子の透過率の測定から0.2meVから100meVの範囲で全断面積を測定した結果を報告する。測定した全断面積は、エネルギーが低くなるにつれて大きくなり、グラファイトと比較すると0.2meVで約2桁以上高くなることが分かった。その全断面積に占める非弾性散乱の寄与を調べるため、中性子のエネルギー1.2, 1.5, 1.9及び5.9meVで中性子非弾性散乱実験を行った。その結果、測定したエネルギーにおいて、全断面積に占める非弾性散乱の寄与がほぼ無視できることも分かった。さらに、中性子小角散乱実験の結果から、全断面積の高くなる要因として、前方方向、いわゆる小角方向への散乱の寄与が高いことが示された。



国井 克彦; 板橋 慶造; 米澤 稔

JAEA-Review 2019-002, 237 Pages, 2019/03


1987年より2014年まで、国際エネルギー機関(International Energy Agency: IEA)の下でエネルギー技術データ交換(Energy Technology Data Exchange: ETDE)計画が実施された。ETDEは原子力を含むエネルギー分野全般にわたる科学技術文献情報を精力的に収集し、それらを加盟国、のちに途上国、さらに最終的には全世界にオンラインで無償提供するに至った。国際原子力機関(International Atomic Energy Agency: IAEA)下の、原子力エネルギー関連情報を専門とする国際原子力情報システム(International Nuclear Information system: INIS)とは、データベースの多くの要素を相互に補間及び共有する形をとってきた。ETDEが活動を停止した2014年からは文献情報データは追加されていないが、ETDEのデータを公開したポータルサイトETDE World Energy Base(ETDEWEB)は、ETDEの運営機関(Operating Agent: OA)であった米国エネルギー省(Department of Energy: DOE)/科学技術情報オフィス(Office of Scientific and Technical Information: OSTI)の尽力により、無償での利用が継続されるに至っている。旧科学技術庁(現文部科学省)下の旧日本原子力研究所(原研、現日本原子力研究開発機構)は、旧通商産業省(現経済産業省)下の新エネルギー・産業技術総合開発機構(New Energy and Industrial Technology Development Organization: NEDO)とともに日本代表として1/2ずつの分担金を負担する形でそのETDE活動に参加した。原研とNEDOは共に2002年にETDEからの脱退を決定しETDE側に通知し、2003年に正式にETDEから退いた。原研は、INISの枠組みとも合わせてNEDOと共に2002年まで、ETDEへの文献情報の提供に貢献した。本報告は、日本からの参加2機関の内の1機関である原研において実施されたETDE活動について、残された資料等からその足跡をたどり、記録として取りまとめたものである。また、日本からのETDE活動への参加に関し、長年にわたり多大な努力及び貢献を重ねていった原研職員、またNEDO職員に対し、感謝の意を記すものである。

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