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Validation of feedback reactivity evaluation models for plant dynamics analysis code during unprotected loss of heat sink event in sodium-cooled fast reactors

吉村 一夫; 堂田 哲広; 井川 健一*; 田中 正暁; 山野 秀将

Journal of Nuclear Engineering and Radiation Science, 9(2), p.021601_1 - 021601_9, 2023/04



Application of 1D-CFD coupling method to unprotected loss of heat sink event in EBR-II focusing on thermal stratification in cold pool

吉村 一夫; 堂田 哲広; 藤崎 竜也*; 井川 健一*; 田中 正暁; 山野 秀将

Proceedings of 29th International Conference on Nuclear Engineering (ICONE 29) (Internet), 10 Pages, 2022/08



ナトリウム冷却高速炉の設計最適化フレームワークの開発,1; 連成解析制御機能の開発

堂田 哲広; 中峯 由彰*; 井川 健一*; 岩崎 隆*; 村上 諭*; 田中 正暁

計算工学講演会論文集(CD-ROM), 27, 6 Pages, 2022/06



Magnetic phase diagram of helimagnetic Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ (0 $$leq$$ x $$leq$$ 0.2) hexagonal ferrite

丸山 建一*; 田中 誠也*; 鬼柳 亮嗣; 中尾 朗子*; 森山 健太郎*; 石川 喜久*; 天児 寧*; 飯山 拓*; 二村 竜祐*; 内海 重宣*; et al.

Journal of Alloys and Compounds, 892, p.162125_1 - 162125_8, 2022/02

 被引用回数:1 パーセンタイル:15.5(Chemistry, Physical)

Hexagonal ferrite Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ is an important magnetic oxide material in both science and engineering because it exhibits helimagnetism around room temperature (300 K). In this study, the magnetic phase diagram of Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ consisting of ferri-, heli-, antiferro-, and paramagnetic phases has been completed through magnetization and neutron diffraction measurements. The magnetic phase transition temperature to paramagnetism decreases with the increase in x, and the temperature at which the magnetization reaches a maximum, which corresponds to the magnetic phase transition from heli- to ferrimagnetism, is determined for low x crystals. The temperatures at which helimagnetism appears are precisely determined by observing the magnetic satellite reflection peaks in neutron diffraction at various temperatures, which characterize helimagnetism. Based on these results, the magnetic phase diagram of the Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ system is constructed in the T-x plane. Helimagnetism appears at x $$>$$ 0.06, and magnetism with antiferromagnetic components appears as the extension phase of helimagnetism at x $$>$$ 0.19 through the coexistence region. The turn angle $$phi_{0}$$ of the helix for each x crystal is calculated from the relationship, $$phi_{0} = 2pidelta$$, where $$delta$$ is the incommensurability. The turn angle $$phi_{0}$$ decreases with the increase in temperature for the same x crystal, and increases with the increase in x at the same temperature. Furthermore, it is found that there are clear thresholds at which $$phi_{0}$$ cannot take values between 0$$^{circ}$$ < $$phi_{0}$$ < 90$$^{circ}$$ and 170$$^{circ}$$ < $$phi_{0}$$ < 180$$^{circ}$$.


High spatial resolution neutron transmission imaging using a superconducting two-dimensional detector

宍戸 寛明*; 西村 和真*; Vu, TheDang*; 相澤 一也; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 奥 隆之; 曽山 和彦; et al.

IEEE Transactions on Applied Superconductivity, 31(9), p.2400505_1 - 2400505_5, 2021/12

 被引用回数:0 パーセンタイル:0(Engineering, Electrical & Electronic)

中性子イメージングは、重金属に対する高透過性、軽元素に対する高感度、同位体と中性子との特異な核反応による同位体選択性などの中性子ビームの特徴を活かした非破壊検査の有力な手段の一つである。本研究では、超伝導検出器である電流バイアス運動インダクタンス検出器(CB-KID)を用いて、パルス中性子源を用いた飛行時間法による波長分解中性子イメージングを行った。遅延時間型CB-KIDを用いて、GdAl$$_{3}$$単結晶を成長させたGd-Al合金試料の中性子透過像を取得した。その結果、単結晶はAl-Gd合金全体に渡って、形状,分布ともに良好に観察することができた。また、中性子の波長0.03nm以上でGdによる特徴的な中性子の吸収を確認した。さらに、15$$mu$$m$$ times$$ 12$$mu$$mという限られた検出面で、同位体と中性子の核反応によって生じる$$^{155}$$Gd共鳴ディップを観測することができた。また、$$^{155}$$Gdの共鳴ディップを用いてGd選択的イメージングを行ったところ、中性子の波長幅が1pmという限られた範囲で、明確なGd核の元素選択イメージング像を取得することに成功した。


Hybridization of Bogoliubov quasiparticles between adjacent CuO$$_2$$ layers in the triple-layer cuprate Bi$$_2$$Sr$$_2$$Ca$$_2$$Cu$$_3$$O$$_{10+delta}$$ studied by angle-resolved photoemission spectroscopy

出田 真一郎*; Johnston, S.*; 吉田 鉄平*; 田中 清尚*; 森 道康; 安齋 太陽*; 井野 明洋*; 有田 将司*; 生天目 博文*; 谷口 雅樹*; et al.

Physical Review Letters, 127(21), p.217004_1 - 217004_6, 2021/11

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

Hybridization of Bogoliubov quasiparticles (BQPs) between the CuO$$_2$$ layers in the triple-layer cuprate high-temperature superconductor Bi$$_2$$Sr$$_2$$Ca$$_2$$Cu$$_3$$O$$_{10+delta}$$ is studied by angle-resolved photoemission spectroscopy (ARPES). In the superconducting state, an anti-crossing gap opens between the outer- and inner-BQP bands, which we attribute primarily to interlayer single-particle hopping with possible contributions from interlayer Cooper pairing. We find that the $$d$$-wave superconducting gap of both BQP bands smoothly develops with momentum without abrupt jump in contrast to a previous ARPES study. Hybridization between the BQPs also gradually increases in going from the off-nodal to the anti-nodal region, which is explained by the momentum-dependence of the interlayer single-particle hopping. As possible mechanisms for the enhancement of the superconducting transition temperature, the hybridization between the BQPs, as well as the combination of phonon modes of the triple CuO$$_2$$ layers and spin fluctuations are discussed.


Practical tests of neutron transmission imaging with a superconducting kinetic-inductance sensor

Vu, TheDang; 宍戸 寛明*; 相澤 一也; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 奥 隆之; 曽山 和彦; 宮嶋 茂之*; et al.

Nuclear Instruments and Methods in Physics Research A, 1006, p.165411_1 - 165411_8, 2021/08

 被引用回数:0 パーセンタイル:0.02(Instruments & Instrumentation)

We found that the sizes of the Gd islands determined from the transmission image correlated strongly with those determined from the SEM image. We demonstrated the CB-KID could be used to identify (1) tiny voids in a thermally sprayed continuous Gd$$_2$$O$$_3$$ film in and (2) various mosaic morphologies and different eutectic microstructures in Wood's metal samples. The fact that the CB-KID system could be used to identify features of samples with a wide distribution of sizes and thicknesses is promising for real application of the device for imaging samples of interest to material scientists. Operating the CB-KID at higher temperatures appreciably improved the efficiency for simultaneously identifying the X and Y positions of hotspots. We also compared the detection efficiency with the PHITS simulations. We now plan to improve the detection efficiency by increasing the thickness of the $$^{10}$$B neutron conversion layer


Rabi-oscillation spectroscopy of the hyperfine structure of muonium atoms

西村 昇一郎*; 鳥居 寛之*; 深尾 祥紀*; 伊藤 孝; 岩崎 雅彦*; 神田 聡太郎*; 川越 清以*; Kawall, D.*; 河村 成肇*; 黒澤 宣之*; et al.

Physical Review A, 104(2), p.L020801_1 - L020801_6, 2021/08

 被引用回数:7 パーセンタイル:81.08(Optics)

As a method to determine the resonance frequency, Rabi-oscillation spectroscopy has been developed. In contrast to conventional spectroscopy which draws the resonance curve, Rabi-oscillation spectroscopy fits the time evolution of the Rabi oscillation. By selecting the optimized frequency, it is shown that the precision is twice as good as conventional spectroscopy with a frequency sweep. Furthermore, the data under different conditions can be treated in a unified manner, allowing more efficient measurements for systems consisting of a limited number of short-lived particles produced by accelerators such as muons. We have developed a fitting function that takes into account the spatial distribution of muonium and the spatial distribution of the microwave intensity to apply this method to ground-state muonium hyperfine structure measurements at zero field. It was applied to the actual measurement data, and the resonance frequencies were determined under various conditions. The result of our analysis gives $$nu_{rm HFS}$$ = 4 463 301.61 $$pm$$ 0.71 kHz.


Validation of evaluation method of feedback reactivity for plant dynamics analysis code during unprotected loss of heat sink event in sodium-cooled fast reactors

吉村 一夫; 堂田 哲広; 田中 正暁; 山野 秀将; 井川 健一*

Proceedings of 28th International Conference on Nuclear Engineering (ICONE 28) (Internet), 8 Pages, 2021/08

プラント動特性解析コードSuper-COPDに組み込まれたフィードバック反応度評価手法の妥当性確認のため、米国高速実験炉EBR-IIで行われた、炉停止失敗と2次主循環ポンプ停止を重畳させたULOHS模擬試験(BOP-302R, BOP-301試験)のベンチマーク解析を実施した。炉心入口温度及び原子炉出力の実測データと解析結果の比較から、Super-COPDのフィードバック反応度評価手法のULOHS事象への適用性を確認した。


Homogeneity of neutron transmission imaging over a large sensitive area with a four-channel superconducting detector

Vu, TheDang; 宍戸 寛明*; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 宮嶋 茂之*; 奥 隆之; 曽山 和彦; 相澤 一也; et al.

Superconductor Science and Technology, 34(1), p.015010_1 - 015010_10, 2021/01

 被引用回数:3 パーセンタイル:44.08(Physics, Applied)

We demonstrated that a four-readout superconducting neutron imaging system shows good spatial heterogeneity and linearity using the delay-line method. We examined the precise pattern of a $$^{10}$$B-dot-array absorber and found the X-direction pitch (Px) = 250.7 um with a scatter of (Hx)= 5.4 um and the Y-direction pitch (Py)= 249.1 um with a scatter of (Hy)= 3.4 um while the $$^{10}$$B dot array was fully extended toward the X direction across the detector sensitive area. We consider that this demonstrates detection with good spatial homogeneity and conclude. The transmission-imaging system is suitable for use at pulsed neutron facilities. We also reported a clear transmission image of tiny screws and nuts, and ladybug (insect). We recognize that further efforts to improve the detection efficiency are necessary to make using the detector more practical.


Flux growth and magnetic properties of helimagnetic hexagonal ferrite Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ single crystals

内海 重宣*; 田中 誠也*; 丸山 建一*; 天児 寧*; 鬼柳 亮嗣; 中尾 朗子*; 森山 健太郎*; 石川 喜久*; 他9名*

ACS Omega (Internet), 5(38), p.24890 - 24897, 2020/09

 被引用回数:3 パーセンタイル:21.3(Chemistry, Multidisciplinary)

六方晶フェライトBa(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$の磁気構造を解明し、さらなる応用開発を進めるためには、大型の高品質な単結晶を育成することが重要な第一歩である。本研究では、Na$$_{2}$$O-Fe$$_{2}$$O$$_{3}$$フラックスを使用した自発結晶化法によって、さまざまなSc濃度$$x$$のBa(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$単結晶の育成に成功した。得られた結晶は、高品質の単相Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$であることがX線回折と元素分析により確認され、$$x$$ = 0.128結晶の77Kの磁化測定では、ヘリマグネティックな挙動を示すことがわかった。$$x$$=0.128結晶の中性子回折測定の結果、211K以下で磁気衛星反射が確認され、Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$がヘリ磁性物質であることが確認された。


Experimental study of Gamow-Teller transitions via the high-energy-resolution $$^{18}$$O($$^3$$He,$$t$$)$$^{18}$$F reaction; Identification of the low-energy "super" -Gamow-Teller state

藤田 浩彦*; 藤田 佳孝*; 宇都野 穣; 吉田 賢市*; 足立 竜也*; Algora, A.*; Csatl$'o$s, M.*; Deaven, J. M.*; Estevez-Aguado, E.*; Guess, C. J.*; et al.

Physical Review C, 100(3), p.034618_1 - 034618_13, 2019/09


 被引用回数:10 パーセンタイル:77.61(Physics, Nuclear)



New precise measurements of muonium hyperfine structure at J-PARC MUSE

Strasser, P.*; 阿部 充志*; 青木 正治*; Choi, S.*; 深尾 祥紀*; 東 芳隆*; 樋口 嵩*; 飯沼 裕美*; 池戸 豊*; 石田 勝彦*; et al.

EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01

 被引用回数:12 パーセンタイル:99.37

High precision measurements of the ground state hyperfine structure (HFS) of muonium is a stringent tool for testing bound-state quantum electrodynamics (QED) theory, determining fundamental constants of the muon magnetic moment and mass, and searches for new physics. Muonium is the most suitable system to test QED because both theoretical and experimental values can be precisely determined. Previous measurements were performed decades ago at LAMPF with uncertainties mostly dominated by statistical errors. At the J-PARC Muon Science Facility (MUSE), the MuSEUM collaboration is planning complementary measurements of muonium HFS both at zero and high magnetic field. The new high-intensity muon beam that will soon be available at H-Line will provide an opportunity to improve the precision of these measurements by one order of magnitude. An overview of the different aspects of these new muonium HFS measurements, the current status of the preparation for high-field measurements, and the latest results at zero field are presented.


福島事故廃棄物を対象とした$$^{93}$$Zr, $$^{93}$$Mo, $$^{107}$$Pd及び$$^{126}$$Sn分析法の開発

青野 竜士; 佐藤 義行; 島田 亜佐子; 田中 究; 上野 隆; 石森 健一郎; 亀尾 裕

JAEA-Technology 2017-025, 32 Pages, 2017/11


福島第一原子力発電所で生じた事故廃棄物を対象として抽出された処分安全評価上重要となる放射性核種のうち、分析手法が定まっていない$$^{93}$$Zr, $$^{93}$$Mo, $$^{107}$$Pd及び$$^{126}$$Snの4核種の分析法を開発した。主要な分析対象試料として、福島第一原子力発電所構内で採取された滞留水・処理水を想定した。この滞留水・処理水中に含まれる$$^{93}$$Zr, $$^{93}$$Mo, $$^{107}$$Pd及び$$^{126}$$Snに対して、目的核種の分離・精製法の開発、回収率向上に取り組み、この成果を本報告にまとめた。


New precise measurement of muonium hyperfine structure interval at J-PARC

上野 恭裕*; 青木 正治*; 深尾 祥紀*; 東 芳隆*; 樋口 嵩*; 飯沼 裕美*; 池戸 豊*; 石田 勝彦*; 伊藤 孝; 岩崎 雅彦*; et al.

Hyperfine Interactions, 238(1), p.14_1 - 14_6, 2017/11

 被引用回数:3 パーセンタイル:87.03

MuSEUM is an international collaboration aiming at a new precise measurement of the muonium hyperfine structure at J-PARC (Japan Proton Accelerator Research Complex). Utilizing its intense pulsed muon beam, we expect a ten-fold improvement for both measurements at high magnetic field and zero magnetic field. We have developed a sophisticated monitoring system, including a beam profile monitor to measure the 3D distribution of muonium atoms to suppress the systematic uncertainty.


Radiochemical analysis of rubble collected from around and inside reactor buildings at Units 1 to 4 in Fukushima Daiichi Nuclear Power Station

佐藤 義行; 青野 竜士; 今田 未来; 田中 究; 上野 隆; 石森 健一郎; 亀尾 裕

Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 13 Pages, 2017/00




佐藤 義行; 田中 究; 上野 隆; 石森 健一郎; 亀尾 裕

保健物理, 51(4), p.209 - 217, 2016/12

福島第一原子力発電所で発生した廃棄物の処理処分方策を検討するためには、事故廃棄物の核種組成を把握する必要がある。そのためには、測定が容易な$$gamma$$線放出核種のみならず、$$alpha$$線や$$beta$$線放出核種に対する放射化学分析データが必要である。そこで本研究では、1, 2及び3号機原子炉建屋内から発生した瓦礫の放射化学分析を行い、$$^{3}$$H, $$^{14}$$C, $$^{60}$$Co, $$^{90}$$Sr, $$^{99}$$Tc, $$^{137}$$Cs, $$^{154}$$Eu, $$^{238, 239+240}$$Pu, $$^{241}$$Am、及び$$^{244}$$Cmの放射能濃度データを取得した。このうち、$$^{3}$$H, $$^{14}$$C, $$^{60}$$Co、及び$$^{90}$$Srについては、それぞれ$$^{137}$$Cs濃度との比例関係の傾向が見られた。瓦礫の核種組成については、1, 2及び3号機で異なることが示唆されたが、これは事故進展の違いを反映しているものと推測される。


New muonium HFS measurements at J-PARC/MUSE

Strasser, P.*; 青木 正治*; 深尾 祥紀*; 東 芳隆*; 樋口 嵩*; 飯沼 裕美*; 池戸 豊*; 石田 勝彦*; 伊藤 孝; 岩崎 雅彦*; et al.

Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12

 被引用回数:7 パーセンタイル:92.31

At the Muon Science Facility (MUSE) of J-PARC (Japan Proton Accelerator Research Complex), the MuSEUM collaboration is planning new measurements of the ground state hyperfine structure (HFS) of muonium both at zero field and at high magnetic field. The previous measurements were performed both at LAMPF (Los Alamos Meson Physics Facility) with experimental uncertainties mostly dominated by statistical errors. The new high intensity muon beam that will soon be available at MUSE H-Line will provide an opportunity to improve the precision of these measurements by one order of magnitude. An overview of the different aspects of these new muonium HFS measurements, the current status of the preparation, and the results of a first commissioning test experiment at zero field are presented.



清水 憲一*; 小池 裕基*; 山田 大貴*; 小原田 和也*; 田中 啓介*; 菖蒲 敬久

材料, 65(9), p.657 - 664, 2016/09




関 晃太郎; 佐々木 誉幸*; 秋元 友寿*; 徳永 貴仁; 田中 究; 原賀 智子; 上野 隆; 石森 健一郎; 星 亜紀子; 亀尾 裕

JAEA-Technology 2016-013, 37 Pages, 2016/07



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