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Revolatilization of iodine by bubbly flow in the suppression pool during an accident

南上 光太郎; 石川 淳; 杉山 智之; Pellegrini, M.*; 岡本 孝司*

Journal of Nuclear Science and Technology, 59(11), p.1407 - 1416, 2022/11

 被引用回数:2 パーセンタイル:58.67(Nuclear Science & Technology)

To appropriately evaluate the amount of radioactive iodine released into the environment, we extended the current pool scrubbing model to consider revolatilization at bubble surfaces due to bubbly flow generated in the suppression pool, and the effect of revolatilization by bubbly flow was quantitatively evaluated using a station black out sequence in this work. Gaseous iodine species are produced in the suppression pool in an accident. They are gradually released from the pool surface, but when a large amount of gas flows from the drywell into the suppression pool, the revolatilization of gaseous iodine dissolved in the pool water is promoted by bubbly flow. The results of this study indicated that the release amount of iodine immediately after suppression chamber (S/C) vent operation increased by up to 134 times when considering the revolatilization effect associated with bubbly flow. These results were due to the increase in the gas-liquid interfacial area at bubble surfaces and the overall mass transfer coefficients under two-phase flow conditions due to bubbly flow. It was shown that caution is required for early S/C vent operation.


Magnetic properties and electronic configurations of Mn ions in the diluted magnetic semiconductor Ba$$_{1-x}$$K$$_x$$(Zn$$_{1-y}$$Mn$$_y$$)$$_2$$As$$_2$$ studied by X-ray magnetic circular dichroism and resonant inelastic X-ray scattering

鈴木 博人*; Zhao, G.*; 岡本 淳*; 坂本 祥哉*; Chen, Z.-Y.*; 野中 洋亮*; 芝田 悟朗; Zhao, K.*; Chen, B.*; Wu, W.-B.*; et al.

Journal of the Physical Society of Japan, 91(6), p.064710_1 - 064710_5, 2022/06

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

The magnetic properties and the electronic excitations of the new diluted magnetic semiconductor Ba$$_{1-x}$$K$$_x$$(Zn$$_{1-y}$$Mn$$_y$$)$$_2$$As$$_2$$ have been studied by X-ray magnetic circular dichroism (XMCD) and resonant inelastic X-ray scattering (RIXS). The sum rule analysis of the XMCD spectra indicates that the Mn atoms are in the high-spin configurations of $$d^5$$, whereas the presence of competing ferromagnetic and antiferromagnetic interactions between the Mn ions reduces the net spin moment. Based on a comparison of the RIXS line shapes with those of Ga$$_{1-x}$$Mn$$_x$$As, it is concluded that the ground state of Mn in Ba$$_{1-x}$$K$$_x$$(Zn$$_{1-y}$$Mn$$_y$$)$$_2$$As$$_2$$ consists of both the $$3d^5 underline{L}$$ and $$3d^5$$ electron configurations.



川崎 浩平; 品田 健太; 岡本 成利; 影山 十三男; 江田 考志; 岡崎 日路; 鈴木 弘道; 山本 和也; 小田部 隼

JAEA-Technology 2020-025, 80 Pages, 2021/03




Influences of the ZrC coating process and heat treatment on ZrC-coated kernels used as fuel in Pu-burner high temperature gas-cooled reactor in Japan

相原 純; 植田 祥平; 本田 真樹*; 水田 直紀; 後藤 実; 橘 幸男; 岡本 孝司*

Journal of Nuclear Science and Technology, 58(1), p.107 - 116, 2021/01

 被引用回数:0 パーセンタイル:0.01(Nuclear Science & Technology)




石仙 順也; 赤坂 伸吾*; 清水 修; 金沢 浩之; 本田 順一; 原田 克也; 岡本 久人

JAEA-Technology 2020-011, 70 Pages, 2020/10


日本原子力研究開発機構原子力科学研究所のウラン濃縮研究棟は、昭和47年に建設され、ウラン濃縮技術開発に関する研究等に用いられてきた。本施設では、平成元年度に発煙事象、平成9年度に火災事故が発生している。本施設は、平成10年度にウラン濃縮に関する研究は終了し、平成24年度に核燃料物質の搬出等を行い廃止措置に着手した。令和元年度、フード等の設備及び火災等による汚染が残存している管理区域の壁, 天井等の解体撤去を行い、管理区域内に汚染が残存していないことを確認して管理区域を解除し、廃止措置を完了した。解体撤去作業において発生した放射性廃棄物は、可燃性廃棄物が約1.7t、不燃性廃棄物が約69.5tである。今後は一般施設として、コールド実験等に利用される。


Microstructures of ZrC coated kernels for fuel of Pu-burner high temperature gas-cooled reactor in Japan

相原 純; 植田 祥平; 本田 真樹*; 水田 直紀; 後藤 実; 橘 幸男; 岡本 孝司*

Journal of Nuclear Materials, 522, p.32 - 40, 2019/08

 被引用回数:3 パーセンタイル:37.29(Materials Science, Multidisciplinary)



Development of security and safety fuel for Pu-burner HTGR; Test and characterization for ZrC coating

植田 祥平; 相原 純; 後藤 実; 橘 幸男; 岡本 孝司*

Mechanical Engineering Journal (Internet), 5(5), p.18-00084_1 - 18-00084_9, 2018/10



Study on Pu-burner high temperature gas-cooled reactor in Japan; Design study of fuel and reactor core

後藤 実; 相原 純; 稲葉 良知; 植田 祥平; 深谷 裕司; 岡本 孝司*

Proceedings of 9th International Topical Meeting on High Temperature Reactor Technology (HTR 2018) (USB Flash Drive), 6 Pages, 2018/10



Study on Pu-burner high temperature gas-cooled reactor in Japan; Test and characterization for ZrC coating

植田 祥平; 相原 純; 水田 直紀; 後藤 実; 深谷 裕司; 橘 幸男; 岡本 孝司*

Proceedings of 9th International Topical Meeting on High Temperature Reactor Technology (HTR 2018) (USB Flash Drive), 7 Pages, 2018/10



Development of security and safety fuel for Pu-burner HTGR, 2; Design study of fuel and reactor core

後藤 実; 植田 祥平; 相原 純; 稲葉 良知; 深谷 裕司; 橘 幸男; 岡本 孝司*

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 6 Pages, 2017/07



Development of security and safety fuel for Pu-burner HTGR, 5; Test and characterization for ZrC coating

植田 祥平; 相原 純; 後藤 実; 橘 幸男; 岡本 孝司*

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 4 Pages, 2017/07




近藤 雅裕*; 吉本 達哉*; 石川 淳; 岡本 孝司*

保全学, 15(4), p.79 - 85, 2017/01




照沼 章弘; 三村 竜二; 長島 久雄; 青柳 義孝; 廣川 勝規*; 打它 正人; 石森 有; 桑原 潤; 岡本 久人; 木村 泰久; et al.

JAEA-Review 2016-008, 98 Pages, 2016/07




Conceptual study of a plutonium burner high temperature gas-cooled reactor with high nuclear proliferation resistance

後藤 実; 出町 和之*; 植田 祥平; 中野 正明*; 本田 真樹*; 橘 幸男; 稲葉 良知; 相原 純; 深谷 裕司; 辻 延昌*; et al.

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.507 - 513, 2015/09

高い核拡散抵抗性を有するプルトニウム燃焼高温ガス炉(クリーンバーン炉)の概念が日本原子力研究開発機構から提案されている。高い核拡散抵抗性に加え、更なる安全性向上を目的とし、ZrC被覆を施したPuO$$_{2}$$-YSZ TRISO燃料を導入したクリーンバーン炉の概念検討を行う。本研究では、ZrC被覆を施したPuO$$_{2}$$-YSZ TRISO燃料の製造に関する基盤技術を確立するために製造試験を行う。また、クリーンバーン炉の成立性を確認するためにセキュリティの定量評価、燃料と炉心の設計、及び原子炉の安全評価を行う。本研究は、東京大学,日本原子力研究開発機構,富士電機、及び原子燃料工業により、2014年度から2017年度まで行われる。本発表では、全体計画、及び2014年度に得られた成果について報告する。


Development of the source term PIRT based on findings during Fukushima Daiichi NPPs accident

末廣 祥一*; 杉本 純*; 日高 昭秀; 岡田 英俊*; 溝上 伸也*; 岡本 孝司*

Nuclear Engineering and Design, 286, p.163 - 174, 2015/05

 被引用回数:14 パーセンタイル:77.77(Nuclear Science & Technology)

日本原子力学会のシビアアクシデント評価委員会は、福島第一原子力発電所事故で得られた知見を踏まえ、事故を起こした原子炉におけるデブリの分布や現状を精度よく把握すること、また計算コードによるシビアアクシデントの予測能力を高度化する上で重要な事象を抽出することを目的として、熱水力とソースタームに係る重要度ランク表を作成した。そのうち、ソースタームに係る重要度ランク表(ST PIRT)については、事故進展に従って3つの時間区分と、格納容器内外など9つの区画に区分して専門家が議論と検討を重ね、摘出した68の現象に対して重要度の評価を行うことにより作成した。本報は、作成したソースターム重要度ランク表、及びそれぞれの区分で高い重要度と評価された事象について記載する。


Source term analysis with containment filtered vent system

吉本 達哉*; 石川 淳; 岡本 孝司*; 丸山 結

Proceedings of 9th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-9) (CD-ROM), 5 Pages, 2014/11

Containment Filtered Vent System (CFVS) can prevent the containment vessel failure and reduce the release amount of fission products to the environment. After the Fukushima Daiichi Nuclear Power Plant (NPP) accident, Nuclear Regulation Authority of Japan required licensees to introduce CFVS in all BWR plant in Japan to re-operate nuclear power plant. In this paper, a CFVS model was constructed and the impact of CFVS on source term during a severe accident was analyzed. A main objective in this analysis is to understand potential effect of CFVS on source terms. A series of calculations has been performed for a BWR with Mark-I containment vessel (CV) at present by considering only scrubbing efficiency in a water pool using THALES2 code. A severe accident initiated by station blackout is taken to be analyzed, which is similar with the accident at the Fukushima Daiichi NPP. Four cases; drywell CFVS case, wet well (W/W) CFVS case, W/W direct release case and CV failure case, are analyzed.


Electric control of the spin Hall effect by intervalley transitions

岡本 尚也*; 紅林 秀和*; Trypiniotis, T.*; Farrer, I.*; Ritchie, D. A.*; 齊藤 英治; Sinova, J.*; Ma$v{s}$ek, J.*; Jungwirth, T.*; Barnes, C.*

Nature Materials, 13(10), p.932 - 937, 2014/10

 被引用回数:45 パーセンタイル:86.03(Chemistry, Physical)

Controlling spin-related material properties by electronic means is a key step towards future spintronic technologies. The spin Hall effect has become increasingly important for generating, detecting and using spin currents, but its strength-quantified in terms of the SHE angle-is ultimately fixed by the magnitude of the spin-orbit coupling present for any given material system. However, if the electrons generating the SHE can be controlled by populating different areas of the electronic structure with different SOC characteristic the SHE angle can be tuned directly within a single sample. Here we report the manipulation of the SHE in bulk GaAs at room temperature by means of an electrical intervalley transition induced in the conduction band. The spin Hall angle was determined by measuring an electromotive force driven by photoexcited spin-polarized electrons drifting through GaAs Hall bars. By controlling electron populations in different valleys, we manipulated the angle from 0.0005 to 0.02. This change by a factor of 40 is unprecedented in GaAs and the highest value achieved is comparable to that of the heavy metal Pt.


Magnetic and electronic properties of (LaMnO$$_3$$)$$_5$$(SrMnO$$_3$$)$$_5$$ superlattice revealed by resonant soft X-ray scattering

久保田 正人; 山田 浩之*; 中尾 裕則*; 岡本 淳*; 山崎 裕一*; 澤 彰仁*; 村上 洋一*

Japanese Journal of Applied Physics, 53(5S1), p.05FH07_1 - 05FH07_5, 2014/05

 被引用回数:2 パーセンタイル:9.3(Physics, Applied)

We have investigated the magnetic and electronic properties of (LaMnO$$_3$$)$$_5$$(SrMnO$$_3$$)$$_5$$ superlattice fabricated on a lattice-matched La$$_{0.3}$$Sr$$_{0.7}$$Al$$_{0.65}$$Ta$$_{0.35}$$O$$_{3}$$ substrate by resonant soft X-ray scattering. The temperature- and $mbox{boldmath $Q$}$-dependences of the energy spectra were measured around the Mn $$L_{2,3}$$-absorption edges. We successfully observed not only a signal that reflects the valence modulation of Mn ion, but also a magnetic signal reflecting ferromagnetism. Compared with the calculated models, we concluded that the ferromagnetism mainly originates from the magnetic moments at the Mn sites sandwiched by LaO layers.


Antiferromagnetic order of the Co$$^{2+}$$ high-spin state with a large orbital angular momentum in La$$_{1.5}$$Ca$$_{0.5}$$CoO$$_{4}$$

岡本 淳*; 中尾 裕則*; 山崎 裕一*; 和達 大樹*; 田中 新*; 久保田 正人; 堀金 和正*; 村上 洋一*; 山田 和芳*

Journal of the Physical Society of Japan, 83(4), p.044705_1 - 044705_6, 2014/04

 被引用回数:7 パーセンタイル:50.31(Physics, Multidisciplinary)

The antiferromagnetic insulator La$$_{1.5}$$Ca$$_{0.5}$$CoO$$_{4}$$ has been investigated by Co L$$_{2,3}$$-edge and O K-edge X-ray absorption spectroscopy (XAS) measurements and Co L$$_{2,3}$$-edge resonant soft X-ray magnetic scattering (RXMS)measurement to determine the Co electronic structures associated with magnetic ordering. Co L$$_{2,3}$$-edge linear-dichroic XAS shows that Co$$^{2+}$$ takes a high-spin (HS) state and Co$$^{3+}$$ takes a low-spin (LS) state. Using Co L$$_{2,3}$$-edge RXMS, we directly determined that an antiferromagnetic order is formed with a HS state of Co$$^{2+}$$ ions. Moreover, the spin and orbital angular momenta of the Co$$^{2+}$$ HS state are quantitatively estimated to be 1.1$$pm$$0.1 and 1.0$$pm$$0.1, respectively, and to align parallel in the ab plane by utilizing the cluster model calculation. The large orbital angular momentum of the Co$$^{2+}$$ HS state originates from the small $$D_{4h}$$-symmetry crystal field splitting of $$t_{2g}$$ levels, which is comparable with the spin-orbit coupling constant of the Co 3$$d$$ orbital.


Measurements of electron-induced neutrons as a tool for determination of electron temperature of fast electrons in the task of optimization laser-produced plasma ions acceleration

榊 泰直; 西内 満美子; 前田 祥太; 匂坂 明人; Pirozhkov, A. S.; Pikuz, T.; Faenov, A.*; 小倉 浩一; 深見 智代; 松川 兼也*; et al.

Review of Scientific Instruments, 85(2), p.02A705_1 - 02A705_4, 2014/02

 被引用回数:2 パーセンタイル:11.84(Instruments & Instrumentation)


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