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論文

Neutron transmission measurements for silica glass at the KURNS-LINAC

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

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.

論文

Quantitative evaluation of leakage flow rate in the sealing part using graphite gland packing to mount a hydrogen separation membrane tube for HI decomposition membrane reaction

杉本 千紘; Myagmarjav, O.; 田中 伸幸; 野口 弘喜; 竹上 弘彰; 久保 真治

International Journal of Hydrogen Energy, 95, p.98 - 107, 2024/12

The thermochemical iodine-sulfur (IS or SI) process can produce hydrogen by decomposing water through chemical reactions and nuclear heat. The hydrogen iodine (HI) decomposition reaction of the IS process thermally decomposes HI at ca. 500$$^{circ}$$C to produce hydrogen. The thermal efficiency of hydrogen production in the thermochemical IS process can be effectively enhanced using a membrane reactor for the HI decomposition reaction; hydrogen separation membrane tubes made of ceramic are attached to a tube plate via sealing parts. The applicability of a sealing method using the expanded graphite grand packing was investigated. During 50 thermal cycles ranging between 25 $$^{circ}$$C-450 $$^{circ}$$C and gas pressure of 0.2-0.8 MPa (gauge), the leakage flow rate was approximately 2$$times$$10$$^{-5}$$ Pa m$$^{3}$$ s$$^{-1}$$. This value is comparable to a detection limit of the standard bubble leak test, indicating that this sealing method works effectively.

論文

Development of a forward Monte Carlo based weight-window generator using the history-counter function in PHITS

佐藤 達彦; 橋本 慎太郎; M$'a$rquez Dami$'a$n, J. I.*; 仁井田 浩二*

Nuclear Instruments and Methods in Physics Research B, 557, p.165535_1 - 165535_8, 2024/12

 被引用回数:0

Appropriate use of the variance reduction techniques such as weight-windows are indispensable for effectively designing the radiation shielding based on the Monte Carlo simulation. In this study, we developed a new algorithm of weight-window generator (WWG) relying solely on forward Monte Carlo simulation and implemented it into the Particle and Heavy Ion Transport code System (PHITS). Our new algorithm leverages a PHITS-specific function called the "history counter", which serves as an event logger that can be arbitrarily defined by users. The performance of the new WWG was investigated by conducting benchmark simulations for both idealized and practical shielding calculations. The results of the benchmark simulations suggested that our new algorithm can reduce the computational time by up to an order of magnitude, though it becomes less beneficial when no apparent pathway for particles arriving in the tally regions is observed in generating the weight window values. With this new feature, PHITS has become further suitable for the shielding calculations against high-energy radiations even when their evaluated cross-section data are unavailable.

論文

Developing an online composition prediction for an HI-I$$_{2}$$-H$$_{2}$$O system using deep neural network

田中 伸幸; 竹上 弘彰; 野口 弘喜; 上地 優; Myagmarjav, O.; 小野 正人; 杉本 千紘

Chemical Engineering Science, 299, p.120479_1 - 120479_11, 2024/11

 被引用回数:0 パーセンタイル:0.00(Engineering, Chemical)

熱化学水素製造法ISプロセスでは、溶液組成を制御して安定な運転を行うため、溶液組成を把握することが求められる。本研究では、深層ニューラルネットワークモデルによる機械学習を用いて、計測可能な物性値から組成をオンラインで予測する手法を開発した。本手法は、従来のサンプリングによる滴定分析と比べて、迅速に溶液組成に関する情報を取得することが出来る。ISプロセスで主要な溶液組成であるHI-I$$_{2}$$-H$$_{2}$$O系において、温度、圧力、溶液密度の測定値から組成を予測できるモデルを作成し、トレンドデータから組成を推定可能であることを示した。また、得られたモデルを解析することで、組成制御に効果的な運転パラメータを明らかにした。

論文

Initial verification and validation of a new CASMO5 JENDL-5 nuclear data library for typical LWR applications

渡邉 友章; 須山 賢也; 多田 健一; Ferrer, R. M.*; Hykes, J.*; Wemple, C. A.*

Nuclear Science and Engineering, 198(11), p.2230 - 2239, 2024/11

 被引用回数:0 パーセンタイル:0.00(Nuclear Science & Technology)

先進的格子計算コードCASMO5用の新しい核データライブラリをJENDL-5に基づいて作成した。JENDL-5では、従来の軽水炉解析に不可欠な多くの核種の核データが最新の評価に基づいて更新されている。新しいJENDL-5ベースのCASMO5ライブラリは、現行のCASMO5用ENDF/B-VII.1ベースのライブラリの核データを可能な限りJENDL-5に置き換えることにより作成された。本研究では、この新しいライブラリの検証と妥当性の確認を行った。OECD/NEA燃焼度クレジット臨界安全ベンチマークフェーズIII-Cに基づき検証を行い、計算されたk$$_{inf}$$及びBWR燃料集合体の燃料組成を報告されているベンチマーク結果と比較した。また、同じベンチマークモデルを用いてMCNP6.2の結果との比較も行った。さらに、TCA臨界実験と高浜3号照射後試験を検証に用いた。その結果、新しいライブラリは、軽水炉システムの反応度及び燃料組成の予測において、ENDF/B-VII.1ベースのライブラリと同等かつ良好な性能を示した。

論文

Study on heat transfer behavior of a cylindrical particle bed with volumetric heating

Wen, J.*; 鎌田 悠斗*; 横山 貢成*; 松元 達也*; Liu, W.*; 守田 幸路*; 今泉 悠也; 田上 浩孝; 松場 賢一; 神山 健司

Proceedings of 13th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS13) (Internet), 8 Pages, 2024/11

The influence of water pool height, particles diameter and wall cooling on particle bed-water pool heat transfer was evaluated by assessing the time variation of average temperatures of the particle bed and water pool, and their difference. The concept of macroscopic heat transfer coefficient of the particle bed-water pool system was introduced to elucidate the intensity of natural convection. The results show that the time variation of temperature difference initially increases, peaks, and then decreases. Based on this phenomenon, the process of heat transfer of the particles bed-water pool system was explained. According to the result, the water pool height and particle diameter will affect the heat transfer, but the current cooling conditions have little influence on the heat transfer of the particle bed.

論文

${it In situ}$ neutron diffraction study to elucidate hydrogen effect on the deformation mechanism in Type 310S austenitic stainless steel

伊東 達矢; 小川 祐平*; Gong, W.; Mao, W.*; 川崎 卓郎; 岡田 和歩*; 柴田 曉伸*; Harjo, S.

Proceedings of the 7th International Symposium on Steel Science (ISSS 2024), p.237 - 240, 2024/11

Hydrogen embrittlement has long been an obstacle to the development of safe infrastructure. However, in contrast to hydrogen's embrittling effect, recent research has revealed that the addition of hydrogen improves both the strength and uniform elongation of AISI Type 310S austenitic stainless steel. A detailed understanding of how hydrogen affects the deformation mechanism of this steel could pave the way for the development of more advanced materials with superior properties. In the present study, ${it in situ}$ neutron diffraction experiments were conducted on Type 310S steel with and without hydrogen-charged to investigate the effect of hydrogen on the deformation mechanism. In addition to the effect of solid-solution strengthening by hydrogen, the q-value, a parameter representing the proportion of edge and screw dislocations in the accumulated dislocations, was quantitatively evaluated using CMWP analysis on neutron diffraction patterns. The comparison of q-values between the hydrogen-charged and non-charged samples reveals that hydrogen has minimal effect on dislocation character in Type 310S steel.

論文

Redifining RADEN's high-resolution neutron imaging capabilities

Sans-Planell, O.*; 篠原 武尚; Grazzi, F.*; Cantini, F.*; Su, Y. H.; 松本 吉弘*; Parker, J. D.*; Manke, I.*

Review of Scientific Instruments, 95(11), p.113702_1 - 113702_5, 2024/11

This study presents a significant development in the Energy-Resolved Neutron Imaging System RADEN, in the Japan Proton Accelerator Research Complex, Japan. Through a systematic study, the collimation power of the facility was reevaluated. To perform the calculation of the L/D factor of the beam, a state-of-the-art method has been used, along with a standard reference sample to measure the resolution of neutron images. To add robustness to the results, the study compares five different scintillators of different composition and thickness.

報告書

Heat transfer coefficients model for SIMMER-III and SIMMER-IV

Brear, D. J.*; 近藤 悟; 曽我部 丞司; 飛田 吉春*; 神山 健司

JAEA-Research 2024-009, 134 Pages, 2024/10

JAEA-Research-2024-009.pdf:2.45MB

SIMMER-III/SIMMER-IVは液体金属高速炉の炉心崩壊事故(CDA)の解析に使用する計算コードである。CDAの事象進展は炉心物質間の熱伝達係数(HTC)により大きく影響される。溶融・固化、蒸発・凝縮といった質量移行現象も熱伝達により支配される。複雑な多相・多成分系においては、一つの流体成分と他の流体又は構造材表面との間での多数の異なるHTCを計算する必要がある。また、多相流の流動様式や構造材の配位に従って異なる伝熱モードを考慮する必要もある。結果として、各計算セルごとに数十のHTCが計算される。本報告書には、SIMMER-III/SIMMER-IVのHTCモデルの役割、選定したHTC相関式とその技術的背景、流動様式の取扱いとHTCの内挿方法、検証及び妥当性確認の成果概要を記載する。

論文

Martensitic transformation-governed Luders deformation enables large ductility and late-stage strain hardening in ultrafine-grained austenitic stainless steel at low temperatures

Mao, W.*; Gao, S.*; Gong, W.; 川崎 卓郎; 伊東 達矢; Harjo, S.; 辻 伸泰*

Acta Materialia, 278, p.120233_1 - 120233_13, 2024/10

 被引用回数:1 パーセンタイル:71.29(Materials Science, Multidisciplinary)

Using a hybrid method of in situ neutron diffraction and digital image correlation, we found that ultrafine-grained 304 stainless steel exhibits Luders deformation after yielding, in which the deformation behavior changes from a cooperation mechanism involving dislocation slip and martensitic transformation to one primarily governed by martensitic transformation, as the temperature decreases from 295 K to 77 K. Such martensitic transformation-governed Luders deformation delays the activation of plastic deformation in both the austenite parent and martensite product, resulting in delayed strain hardening. This preserves the strain-hardening capability for the later stage of deformation, thereby maintaining a remarkable elongation of 29% while achieving a high tensile strength of 1.87 GPa at 77 K.

論文

The Impact of climate on relief in the northern Japanese Alps within the past 1 Myr; The case of the Tateyama mountains

Bartz, M.*; King, G. E.*; Bernard, M.*; Herman, F.*; Wen, X.*; 末岡 茂; 塚本 すみ子*; Braun, J.*; 田上 高広*

Earth and Planetary Science Letters, 644, p.118830_1 - 118830_11, 2024/10

 被引用回数:0 パーセンタイル:0.00(Geochemistry & Geophysics)

The impact of climate on mountain relief is unknown, mainly due to the difficulties of measuring surface processes at the timescale of glacial-interglacial cycles. An appropriate setting for studying mountain erosion in response to Quaternary climate change is found in the Tateyama mountains in the Hida mountain range (northern Japanese Alps) due to distinct geomorphological features of glacial, periglacial, and fluvial processes. The Japanese Alps uplifted within the past ca 1-3 Myr and experienced multiple glaciations during the late Quaternary. We use ultra-low temperature thermochronometers based on the luminescence of feldspar minerals and the electron spin resonance (ESR) of quartz minerals, in combination with inverse modelling to derive rock cooling rates and exhumation rate histories at 10$$^{4}$$-10$$^{6}$$ year timescales from 19 rock samples from three transects in the Tateyama region. While luminescence signals have already reached their upper dating limit, ESR signals (Al and Ti centres) yielded ESR ages of ca 0.3-1.1 Ma, implying surface processes active in the Pleistocene. Based on a negative age-elevation relationship, local relief reduction at a cirque-basin scale is identified over the past 1 Myr, whereas a positive age distribution with elevation for samples close to the mountain top does not follow this trend. Inverse modelling reveals rock cooling rates on the order of 30-80 deg. C/Ma, with slightly faster cooling for cirque-floor samples, which equate with erosion rates of 0.5-1 mm/yr that exceed rates from periglacial and fluvial processes in the same locality. Thus, our data suggest that Quaternary climate change coupled with distinct surface processes modified the slopes of the Tateyama mountains leading to a localised decrease in relief over the second half of the Quaternary, whilst the mountain peaks were unaffected by the relief reduction.

論文

Nondestructive analysis of internal crystallographic structures of Japanese swords using neutron imaging

松本 吉弘*; 及川 健一; 渡辺 賢一*; 佐藤 博隆*; Parker, J. D.*; 篠原 武尚; 鬼柳 善明*

Journal of Archaeological Science; Reports, 58, p.104729_1 - 104729_10, 2024/10

We investigated the internal crystallographic structures of Japanese swords using a nondestructive analysis method that combines neutron Bragg-edge transmission (BET) imaging and neutron tomography. BET provides insights into the crystalline structure of the steel, while the neutron tomography offers cross-sectional views of the sword. To systematically explore and understand the technical and historical transition of Japanese sword-making methods, it is important to analyze the internal crystalline structure of various swords, taking into account factors such as production period, region, and swordsmith. Our study examined three swords: Kashu Kiyomitsu, Nankaitaro Tomotaka, and Hosokawa Masanori. The results reveal distinct differences in the internal structures of these swords. This innovative nondestructive approach allowed us to gain detailed insights into the microstructures of these historical artifacts without causing any damage.

論文

LET-based approximation of the microdosimetric kinetic model for proton radiotherapy

Parisi, A.*; Furutani, K. M.*; 佐藤 達彦; Beltran, C. J.*

Medical Physics, 51(10), p.7589 - 7605, 2024/10

 被引用回数:0 パーセンタイル:0.00(Radiology, Nuclear Medicine & Medical Imaging)

本研究では、陽子線治療における生物学的相対有効性(RBE)モデルの課題に対処するため、LET(線量平均線エネルギー伝達)に基づく近似的なMKM(マイクロドシメトリックキネティックモデル)を開発した。これは、炭素イオン治療で使用されるメカニズムに基づくアプローチを陽子線に適用する試みでる。このLETベースのMKMは、線量平均LETと微生物学的指標の相関を確立し、複数の細胞株に対する生存率のモデリングに成功した。これにより、陽子線治療計画システムで容易に利用可能な物理量に基づくRBEの数学的記述が実現された。

論文

Pearlite growth kinetics in Fe-C-Mn eutectoid steels; Quantitative evaluation of energy dissipation at pearlite growth front via experimental approaches

Zhang, Y.-J.*; 梅田 岳昌*; 諸岡 聡; Harjo, S.; 宮本 吾郎*; 古原 忠*

Metallurgical and Materials Transactions A, 55(10), p.3921 - 3936, 2024/10

 被引用回数:0 パーセンタイル:0.00(Materials Science, Multidisciplinary)

In this study, a series of eutectoid steels with Mn addition up to 2 mass% were isothermally transformed at various temperatures from 873 K to 973 K to clarify the pearlite growth kinetics and the underlying thermodynamics at its growth front. The microscopic observation indicates the acceleration in pearlite growth rate and refinement in lamellar spacing by decreasing the transformation temperature or the amount of Mn addition. After analyzing the solute distribution at pearlite growth front via three-dimensional atom probe, no macroscopic Mn partitioning across pearlite/austenite interface is detected, whereas Mn segregation is only observed at ferrite/austenite interface. Furthermore, in-situ neutron diffraction measurements performed at elevated temperatures reveals that the magnitude of elastic strain generated during pearlite transformation is very small.

論文

The LINACs simulation framework

Yee-Rendon, B.; Jameson, R. A.*; 岡村 昌宏*; Li, C.*; Jiang, P.*; Maus, J. M.*

Proceedings of 32nd Linear Accelerator Conference (LINAC 2024) (Internet), p.492 - 495, 2024/10

LINACsは、粒子加速器内の荷電粒子の光学系とビーム ダイナミクスを設計するためのシミュレーションのフレームワークであり、RFQのすべての設計パラメータとシミュレーションパラメータをユーザーが完全に制御できるオープンソースのフトウェアである。ビーム駆動設計、正確な四極対称性を使用した完全3Dシミュレーション、外部および空間電荷場に対する厳密なポアソン解を含む。本コードは、解析入力分布を伴う粒子ビームを同時に処理でき、入力ビームの状態がスキャン可能である。本ソフトウェアは実行時間が比較的短くかつ広範な分析情報を提供する。本発表では、コードの歴史的な概要を説明するとともにRFQモデルの結果を提示し、将来の開発について議論する。

論文

Automatic retuning of superconducting linacs using LightWin

Pla$c{c}$ais, A.*; Bouly, F.*; Froidefond, E.*; Lagniel, J.-M.*; Normand, G.*; Orduz, A. K.*; Yee-Rendon, B.; De Keukeleere, L.*; Van De Walle, J.*

Proceedings of 32nd Linear Accelerator Conference (LINAC 2024) (Internet), p.563 - 568, 2024/10

高出力粒子加速器にとって信頼性は重要である。特に加速器駆動システム(ADS)では、ビームの停止が原子炉の稼働率に大きく影響し、停止の多くは、加速空洞やその関連システムの損失に起因する。空洞に起因するビーム停止は、リニアックの他の空洞を再調整することで補償できる。しかし、理想的な補償設定を見つけることは、ビームダイナミクスと多目的最適化を伴う難しい課題であり、対象のリニアックによって大きく異なる問題が生じる。SPIRAL2リニアックでは、多くの空洞が補償のために動員され、探索空間は非常に多くの次元を持ち、ビーム進行方向の許容マージンがかなり低い。MYRRHAやJAEAで検討を進めているADS用リニアックには、最適化を容易にする特定の耐故障設計を適用しているものの、空洞は数秒で再調整する必要がある。そこで我々は、任意のリニアックのすべての空洞障害に対する補償設定を自動的かつ体系的に見つけるツールであるLightWinを開発した。本研究では、LightWinの最新の開発状況と、SPIRAL2とADSリニアック用に開発した補償戦略について、ビームダイナミクスと数学的な観点から紹介する。

論文

France-Japan collaboration on severe accident studies in sodium-cooled fast reactors, 3; Thermodynamic, Kinetic, and Thermophysical Studies of Core Material Mixture

山野 秀将; 江村 優軌; 高井 俊秀; 久保 重信; Quaini, A.*; Fossati, P.*; Delacroix, J.*; Journeau, C.*

Proceedings of International Conference on Nuclear Fuel Cycle (GLOBAL2024) (Internet), 4 Pages, 2024/10

本論文では、炉心混合物質の相互作用に関する反応速度論、二酸化ウラン(UO$$_{2}$$)と鉄(Fe)と単価ホウ素(B$$_{4}$$C)に対する高温熱物性データ、B$$_{4}$$Cとステンレス鋼(SS)並びにB$$_{4}$$C-SS共晶物再配置(固化も)に関する実験研究、シビアアクシデントコードにB$$_{4}$$C-SS共晶物と反応モデルを組み込む。

論文

Comparison between carrier transport property and crystal quality of TlBr semiconductors

渡辺 賢一*; 須貝 優介*; 長谷川 創大*; 田中 清志朗*; 人見 啓太朗*; 野上 光博*; 篠原 武尚; Su, Y. H.; Parker, J. D.*; Kockelmann, W.*

Scientific Reports (Internet), 14, p.25224_1 - 25224_13, 2024/10

Thallium bromide (TlBr) semiconductor detectors are being developed as promising candidates for high-detection-efficiency, high-energy-resolution, and room-temperature gamma-ray spectrometers. This study presents methods for evaluating TlBr crystal quality and carrier transport characteristics using neutron Bragg-dip imaging and the time-of-flight method for pulsed-laser-induced carriers, respectively. In this study, two samples obtained from both the upstream and downstream region in the crystal ingot were evaluated.

論文

Iron coupled with hydroxylamine turns on the "switch" for free radical degradation of organic pollutants under high pH conditions

Tian, Q.*; Feng, L.*; Wu, C.*; Wen, J.*; Qiu, X.*; 田中 万也; 大貫 敏彦*; Yu, Q.*

Journal of Colloid and Interface Science, 669, p.1006 - 1014, 2024/09

 被引用回数:0 パーセンタイル:0.00(Chemistry, Physical)

In this study, we assessed the impact of solution pH on organic pollutant degradation by goethite with the addition of hydroxylamine. This study demonstrated that the system can continuously scavenge organic pollutants through oxygen-mediated generation of free radicals under alkaline conditions.

論文

Singular continuous and nonreciprocal phonons in quasicrystal AlPdMn

松浦 直人*; Zhang, J.*; 上村 祥史*; 古府 麻衣子; 枝川 圭一*

Physical Review Letters, 133(13), p.136101_1 - 136101_5, 2024/09

 被引用回数:1

In quasicrystals lacking translational symmetry but having highly ordered structures, understanding how phonons propagate in their aperiodic lattices remains an unsolved issue. We present an inelastic neutron scattering study on acoustic phonon modes of icosahedral quasicrystal AlPdMn, revealing hierarchical pseudo-gap structure in low-energy acoustic modes. Additionally, phonon intensities are asymmetric in energy and wave vectors with respect to the Bragg peak, indicating characteristic nonreciprocal phonon propagation in quasicrystals.

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