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High-temperature rupture failure of high-burnup LWR-MOX fuel under a reactivity-initiated accident condition

谷口 良徳; 三原 武; 垣内 一雄; 宇田川 豊

Annals of Nuclear Energy, 195, p.110144_1 - 110144_11, 2024/01

A reactivity-initiated accident (RIA)-simulated test CN-1 on a high-burnup 64 GWd/t mixed-oxide fuel rod sheathed with M5$$^{TM}$$ cladding was conducted at the Nuclear Safety Research Reactor, resulting in fuel failure. A small opening with slight ballooning deformation characterized the post-test visual appearance of the test fuel rod. Simulation using fuel performance codes FEMAXI-8/RANNS predicted rod survival under early phase loading induced by pellet-cladding mechanical interaction and subsequent boiling transition, and the cladding surface temperature measured online confirmed the occurrence of boiling transition. The experimental observation and simulation indicate that the failure was caused by a high-temperature rupture following increased rod-internal pressure. The RANNS sensitivity analysis revealed that a mechanical state parameter dedicated to predicting plastic instability might be an effective index for evaluating the risk of rupture failure during RIAs.


Probing deformation behavior of a refractory high-entropy alloy using in situ neutron diffraction

Zhou, Y.*; Song, W.*; Zhang, F.*; Wu, Y.*; Lei, Z.*; Jiao, M.*; Zhang, X.*; Dong, J.*; Zhang, Y.*; Yang, M.*; et al.

Journal of Alloys and Compounds, 971, p.172635_1 - 172635_7, 2024/01

The grain orientation-dependent lattice strain evolution of a (TiZrHfNb)$$_{98}$$$$N_2$$ refractory high-entropy alloy (HEA) during tensile loading has been investigated using in situ neutron diffraction. The equivalent strain-hardening rate of each of the primary $$<hkl>$$-oriented grain families was found to be relatively low, manifesting the macroscopically weak work-hardening ability of such a body-centered cubic (BCC)-structured HEA. This finding is indicative of a dislocation planar slip mode that is confined in a few single-slip planes and leads to in-plane softening by high pile-up stresses.


Stress evaluation method by neutron diffraction for HCP-structured magnesium alloy

Harjo, S.; Gong, W.; 川崎 卓郎

Quantum Beam Science (Internet), 7(4), p.32_1 - 32_13, 2023/12

Tensile deformation in situ neutron diffraction of an extruded AZ31 alloy was performed to validate conventional procedures and to develop new procedures for stress evaluation from lattice strains by diffraction measurements of HCP-structured magnesium alloys. Increases in the lattice strains with respect to the applied true stress after yielding largely vary among [${it hk.l}$] grains. The newly proposed procedure of stress evaluation from the lattice strains shows very high accuracy and reliability by weighting the volume fraction of [${it hk.l}$] grains and evaluating them in many [${it hk.l}$] orientations in addition to multiplication by the diffraction elastic constant. When multiple ${it hk.l}$ peaks cannot be obtained simultaneously, we recommend to use the 12.1 peak for stress evaluation.


幌延深地層研究計画; 令和5年度調査研究計画

中山 雅

JAEA-Review 2023-019, 70 Pages, 2023/11





飛田 実*; 後藤 勝則*; 大森 剛*; 大曽根 理*; 原賀 智子; 青野 竜士; 今田 未来; 土田 大貴; 水飼 秋菜; 石森 健一郎

JAEA-Data/Code 2023-011, 32 Pages, 2023/11


日本原子力研究開発機構の研究施設等から発生する放射性廃棄物は、放射能レベルに応じて将来的にトレンチとピットに分けて浅地中埋設処分される予定であり、埋設処分を開始するまでに、廃棄体の放射能濃度を評価する方法を構築する必要がある。そこで、原子力科学研究所バックエンド技術部では、研究施設等廃棄物に対する放射能濃度評価方法の検討に資するため、JRR-3、JRR-4及び再処理特別研究棟から発生した放射性廃棄物よりコンクリートを試料として採取し、放射化学分析を実施した。本報告書は、令和3年度から令和4年度に取得した23核種($$^{3}$$H、$$^{14}$$C、$$^{36}$$Cl、$$^{41}$$Ca、$$^{60}$$Co、$$^{63}$$Ni、$$^{90}$$Sr、$$^{94}$$Nb、$$^{rm 108m}$$Ag、$$^{137}$$Cs、$$^{133}$$Ba、$$^{152}$$Eu、$$^{154}$$Eu、$$^{rm 166m}$$Ho、$$^{234}$$U、$$^{235}$$U、$$^{238}$$U、$$^{238}$$Pu、$$^{239}$$Pu、$$^{240}$$Pu、$$^{241}$$Am、$$^{243}$$Am、$$^{244}$$Cm)の放射能濃度データについて整理し、放射能濃度評価法検討のための基礎資料としてまとめたものである。


An Estimation method for an unknown covariance in cross-section adjustment based on unbiased and consistent estimator

丸山 修平; 遠藤 知弘*; 山本 章夫*

Journal of Nuclear Science and Technology, 60(11), p.1372 - 1385, 2023/11

A new estimation method of an unknown covariance, which is defined by the difference between the true covariance (the population covariance) and a prior covariance assumed by an analyst, is proposed. The unknown covariance is estimated using an empirical covariance consistent with the observed data. To estimate the unknown covariance, an unbiased and consistent estimator in regression analysis has been incorporated into the conventional cross-section adjustment. This estimator does not require assumptions for the probability distribution of the observation data. The statistical properties of this estimator were numerically verified. In addition, the effectiveness of the proposed method was confirmed by another numerical test using actual integral experimental data. In the second numerical test, the modeling uncertainty (covariance) due to the deterministic analysis method was assumed to be unknown. The results showed that the proposed method could practically estimate the unknown covariance and adjusted cross-sections using only prior information on covariances.


Mutual separation of Am and Cm using ADAAM (alkyl DiAmide AMine) and reduction of volumes for liquid waste generated via batch-wise multistage extractions

佐々木 祐二; 金子 政志; 伴 康俊; 鈴木 英哉*

Journal of Nuclear Science and Technology, 11 Pages, 2023/11

アルキルジアミドアミン(ADAAM)を使ったAm/Cm相互分離を行った。ADAAMは硝酸-ドデカン系で非常に高いAm/Cm分離比5.9を示した。1.5M硝酸-0.2M ADAAM条件を用いる多段抽出で抽出後の有機相中にAm 96.5%、Cm 1.06%回収できることを確認した。Am/Cm相互分離後に発生した水相、有機相体積削減のための付加的な多段抽出を行い、Am, Cmを2, 3段の水相に濃縮できることを確認した。


Development of a DDA+PGA-combined non-destructive active interrogation system in "Active-N"

古高 和禎; 大図 章; 藤 暢輔

Nuclear Engineering and Technology, 55(11), p.4002 - 4018, 2023/11

An integrated neutron interrogation system has been developed for non-destructive assay of highly radioactive special nuclear materials, to accumulate knowledge of the method through developing and using it. The system combines a differential die-away (DDA) measurement system for the quantification of nuclear materials and a prompt gamma-ray analysis (PGA) system for the detection of neutron poisons which disturb the DDA measurements; a common D-T neutron generator is used. A special care has been taken for the selection of materials to reduce the background gamma rays produced by the interrogation neutrons. A series of measurements were performed to test the basic performance of the system. The results show that the DDA system can quantify plutonium of as small as 20~mg and it is not affected by intense neutron background up to 4.2~TBq and gamma ray of 2.2~TBq. As a result of the designing of the combined system as a whole, the gamma-ray background counting rate at the PGA detector was reduced down to $$3.9times10^{3}$$ s$$^{-1}$$ even with the use of the D-T neutron generator. The test measurements show that the PGA system is capable of detecting less than 1~g of boron compound and about 100~g of gadolinium compound in~30 min. This research was implemented under the subsidy for nuclear security promotion of MEXT.


Void reactivity in lead and bismuth sample reactivity experiments at Kyoto University Critical Assembly

Pyeon, C. H.*; 方野 量太; 大泉 昭人; 福島 昌宏

Nuclear Science and Engineering, 197(11), p.2902 - 2919, 2023/11

 被引用回数:0 パーセンタイル:82.84(Nuclear Science & Technology)



Predictive and inverse modeling of a radionuclide diffusion experiment in crystalline rock at ONKALO (Finland)

Soler, J. M.*; Kek$"a$l$"a$inen, P.*; Pulkkanen, V.-M.*; Moreno, L.*; Iraola, A.*; Trinchero, P.*; Hokr, M.*; $v{R}$$'i$ha, J.*; Havlov$'a$, V.*; Trpko$v{s}$ov$'a$, D.*; et al.

Nuclear Technology, 209(11), p.1765 - 1784, 2023/11

The REPRO-TDE test was performed at a depth of about 400 m in the ONKALO underground research facility in Finland. Synthetic groundwater containing radionuclide tracers (HTO, Cl-36, Na-22, Ba-133, Cs-134) was circulated for about four years in a packed-off interval of the injection borehole. Tracer activities were additionally monitored in two observation boreholes. The test was the subject of a modelling exercise by the SKB GWFTS Task Force. Eleven teams participated in the exercise, using different model concepts and approaches. Predictive model calculations were based on laboratory-based information concerning porosities, diffusion coefficients and sorption partition coefficients. After the experimental results were made available, the teams were able to revise their models to reproduce the observations. General conclusions from these back-analysis calculations include the need for reduced effective diffusion coefficients for Cl-36 compared to those applicable to HTO (anion exclusion), the need to implement weaker sorption for Na-22, compared to results from laboratory batch-sorption experiments, and the observation of large differences between the theoretical initial concentrations for the strongly-sorbing Ba-133 and Cs-134 and the first measured values a few hours after tracer injection. Different teams applied different concepts, concerning mainly the implementation of isotropic vs. anisotropic diffusion, or the possible existence of Borehole Disturbed Zones around the different boreholes. The role of microstructure was also addressed in two of the models.


Data report of ROSA/LSTF experiment TR-LF-15; Accident management actions during station blackout transient with pump seal LOCA

竹田 武司

JAEA-Data/Code 2023-012, 75 Pages, 2023/10


ROSA-V計画において、大型非定常実験装置(LSTF)を用いた実験(実験番号: TR-LF-15)が2014年6月11日に行われた。ROSA/LSTFTR-LF-15実験では、加圧水型原子炉(PWR)のポンプシール冷却材喪失事故(LOCA)を伴う、補助給水機能喪失を特徴とするTMLB'のシナリオでの全交流電源喪失時のアクシデントマネジメント(AM)策を模擬した。ポンプシールLOCAは、0.1%低温側配管破断により模擬した。このとき、非常用炉心冷却系(ECCS)である高圧注入系及び低圧注入系の全故障とともに、ECCSの蓄圧注入タンクから一次系への非凝縮性ガス(窒素ガス)の流入を仮定した。蒸気発生器(SG)二次側水位が特定の低水位まで低下すると、一次系圧力は上昇に転じた。SG二次側水位喪失後、加圧器の安全弁が周期的に開いたため、一次冷却材の喪失につながった。故に、高圧条件でボイルオフによる炉心露出が生じた。模擬燃料棒被覆管表面温度の10Kの上昇を確認した時点で、SG二次側減圧を一番目のAM策として開始した。このAM策では、両SGの安全弁を開放した。また、一番目のAM策開始後少し遅れた時点で、加圧器の安全弁の開放による一次系減圧を二番目のAM策として開始した。さらに、一番目のAM策に従いSG二次側圧力が1.0MPaに低下した時点で、低水頭ポンプによる給水ラインから両SG二次側への注水を三番目のAM策として開始した。三番目のAM策の開始直後、SG二次系からの除熱が再開したため、一次系圧力の低下が促進された。蓄圧注入系から両低温側配管への冷却材注入による炉心水位の回復により、全炉心はクエンチした。窒素ガスがSGU字管内に蓄積したため、一次系の減圧率は低下した。本報告書は、ROSA/LSTFTR-LF-15実験の手順、条件および実験で観察された主な結果をまとめたものである。


Elucidation of solid particle interfacial phenomena in liquid sodium; Magnetic interactions on liquid metal and solid atoms at the solid interface

Tei, C.; 大高 雅彦; 桑原 大介*

Chemical Physics Letters, 829, p.140755_1 - 140755_6, 2023/10




中村 いずみ*; 大谷 章仁*; 奥田 幸彦; 渡壁 智祥; 滝藤 聖崇; 奥田 貴大; 嶋津 龍弥*; 酒井 理哉*; 渋谷 忠弘*; 白鳥 正樹*

第10回構造物の安全性・信頼性に関する国内シンポジウム(JCOSSAR2023)講演論文集(インターネット), p.143 - 149, 2023/10



Review of JENDL/HE-2007 neutron-induced fission cross sections of uranium-235 and 238 above 200 MeV

深堀 智生

INDC(JPN)-210 (Internet), 5 Pages, 2023/10



Evaluation of thermal expansion reactivity feedback effect in water-moderated fuel-particle-dispersion system

福田 航大

Proceedings of 4th Reactor Physics Asia Conference (RPHA2023) (Internet), 4 Pages, 2023/10



Measurement of mechanical behavior of $$^{11}$$B-enriched MgB$$_{2}$$ wire using a pulsed neutron source

町屋 修太郎*; 長村 光造*; 菱沼 良光*; 谷口 博康*; Harjo, S.; 川崎 卓郎

Quantum Beam Science (Internet), 7(4), p.34_1 - 34_17, 2023/10

Measuring the actual strain on the MgB$$_2$$ filaments are of paramount importance, since tensile stress and strain diminish the critical current. In this study, the strain measurement using neutron diffraction during tensile loading was established. We fabricated a MgB$$_2$$ wire enriched with boron-11, an isotope having a smaller neutron absorption cross- section than natural boron, and succeeded in obtaining changes in the lattice constant under tensile loading through Rietveld analysis.



新居 昌至; 前田 茂貴

臨床放射線, 68(10), p.963 - 970, 2023/10



Pd nanoparticles on the outer surface of microporous aluminosilicates for the direct alkylation of benzenes using alkanes

美崎 慧*; 三輪 寛子*; 伊藤 孝; 吉田 健文*; 長谷川 慎吾*; 中村 由紀奈*; 徳竹 駿太*; 高畠 萌*; 下村 浩一郎*; Chun, W.-J.*; et al.

ACS Catalysis, 13(18), p.12281 - 12287, 2023/09

The direct alkylation of benzenes with simple alkanes is one of the ideal processes for the production of alkylbenzenes. We demonstrated that Pd nanoparticles on the outer surface of H-ZSM-5 are efficient catalysts for direct alkylation. The reaction proceeds through the activation of an alkane on the acid sites present inside the zeolite pores. This process is followed by the nucleophilic addition of an arene to the activated alkane. The spillover of the abstracted hydrogen atoms from the acid sites to the Pd nanoparticles on the outer surface accelerates recombination to H$$_2$$. A maximum toluene conversion of 58.5% and selectivity of 95.6% for the alkylated products are achieved when toluene is reacted with $$n$$-heptane. ${it Para}$-selective alkylation is achieved, due to the effect of the pore size of H-ZSM-5. The $$mu^+$$SR study of muonium, a pseudo-isotope of hydrogen, in aluminosilicates suggested that the formation of atomic hydrogen is possible and its lifetime is in the sub-microsecond range or longer, which is long enough for chemical reactions.


In situ transmission electron microscopy observation of melted germanium encapsulated in multilayer graphene

鈴木 誠也; 根本 善弘*; 椎木 菜摘*; 中山 佳子*; 竹口 雅樹*

Annalen der Physik, 535(9), p.2300122_1 - 2300122_12, 2023/09

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

Germanene is a two-dimensional (2D) germanium (Ge) analogous of graphene, and its unique topological properties are expected to be a material for next-generation electronics. However, no germanene electronic devices have yet been reported. One of the reasons for this is that germanene is easily oxidized in air due to its lack of chemical stability. Therefore, growing germanene at solid interfaces where it is not oxidized is one of the key ideas for realizing electronic devices based on germanene. In this study, the behavior of Ge at the solid interface at high temperatures was observed by transmission electron microscopy (TEM). To achieve such in situ heating TEM observation, we fabricated a graphene/Ge/graphene encapsulated structure. In situ heating TEM experiments revealed that Ge like droplets moved and coalesced with other Ge droplets, indicating that Ge remained as a liquid phase between graphene layers at temperatures higher than the Ge melting point.


Neutron capture cross-section measurement by mass spectrometry for Pb-204 irradiated in JRR-3

中村 詔司; 芝原 雄司*; 木村 敦; 遠藤 駿典; 静間 俊行*

Journal of Nuclear Science and Technology, 60(9), p.1133 - 1142, 2023/09

 被引用回数:0 パーセンタイル:0.02(Nuclear Science & Technology)


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