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Deuterium retention in tungsten coating layers irradiated with deuterium and carbon ions

福本 正勝; 仲野 友英; 上田 良夫*; 伊丹 潔; 久保 博孝

Journal of Nuclear Materials, 462, p.354 - 359, 2015/07

 被引用回数:2 パーセンタイル:74.03(Materials Science, Multidisciplinary)

Deuterium retention in a tungsten coating layer by deuterium and carbon mixed ion beam irradiation has been investigated by changing the carbon ion fraction and the surface temperature. Graphite is formed, while tungsten carbide (WC) and ditungsten carbide (W$$_2$$C) are not formed in the tungsten coating layer. At a surface temperature of 500 K, deuterium is retained in the trapping sites with a single trapping energy, which is expected to be grain boundaries and/or pore surfaces, and carbon retained in the tungsten coating layer. At a surface temperature of 700 K, most of the deuterium is not trapped by intrinsic defects such as grain boundaries and pore surfaces, but trapped by carbon retained in the tungsten coating layer. Analysis of deuterium desorption spectra suggests that deuterium is retained in the form of C-D bond in the tungsten coating layer.


Reactivity of plasma-sintered beryllium-titanium intermetallic compounds with water vapor

金 宰煥; 中道 勝

Journal of Nuclear Materials, 455(1-3), p.26 - 30, 2014/12

 被引用回数:9 パーセンタイル:29.95(Materials Science, Multidisciplinary)

The establishment of the synthesis technique for beryllides is a key issue of the advanced neutron multiplier development. In the previous study, trial fabrication examinations were carried out. Plasma sintering is a non-conventional consolidation process for beryllides synthesis. The synthesis results clarified that the beryllide has been successfully fabricated by this method. In this study, the effect of phase compositions on high temperature reactivity of the plasma-sintered beryllides was evaluated. The beryllides sintered for various times, which they have different phase compositions, were examined by thermal-gravimetry and hydrogen gas generation rate was simultaneously measured at 873 K, 1073 K and 1273 K for 24 hr under Ar gas containing water vapor to investigate the effect of phase compositions on the reactivity with water vapor. The result of weight gains clarified that with increase of the area fraction of Be, oxidation resistance decreases under dry air. H$$_{2}$$ gas generation rates of the beryllides at high temperature demonstrate that the larger fraction of Be the beryllide has, the higher H$$_{2}$$ generation rate it indicates. It is clear that the Be phase in the plasma-sintered beryllide attributes to increase of the H$$_{2}$$ gas generation. In this study, we report on the effect of phase compositions on reactivity with water vapor of the plasma-sintered beryllides which were fabricated with different sintering conditions.


Evaluation of damage accumulation behavior and strength anisotropy of NITE SiC/SiC composites by acoustic emission, digital image correlation and electrical resistivity monitoring

野澤 貴史; 小沢 和巳; 朝倉 勇貴*; 香山 晃*; 谷川 博康

Journal of Nuclear Materials, 455(1-3), p.549 - 553, 2014/12

 被引用回数:10 パーセンタイル:29.95(Materials Science, Multidisciplinary)

SiC/SiC複合材料は核融合DEMO炉の有力な候補材である。本論文は、アコースティックエミッション(AE)測定,電気抵抗(ER)測定,デジタル画像相関(DIC)法等の様々な手法により複合材料の損傷許容性,強度異方性を明らかにすることを目的とした。AEの結果より、2D複合材において、引張及び圧縮試験ともに比例限度応力(PLS)以前より損傷の蓄積が開始することが明らかとなった。波形データの予備検討結果から、AE検出強度は微視的なき裂発生に起因し、強い界面摩擦力からき裂発生後も応力-ひずみ曲線において線形的な振る舞いをしていたことが示唆された。繊維のすべりがPLS近傍で開始し、結果として非線形挙動を示すと考えられる。一方で、ノッチ試験片を用いた予備的な引張試験より、いずれの負荷方位においても複合材料は原則としてノッチ鈍感であることが示唆された。詳細な破損メカニズムについて、ER, DIC試験の結果と併せて、議論する予定である。


Effects of manufacturing process on impact properties and microstructures of ODS steels

丹野 敬嗣; 大塚 智史; 矢野 康英; 皆藤 威二; 田中 健哉

Journal of Nuclear Materials, 455(1-3), p.480 - 485, 2014/12

 被引用回数:9 パーセンタイル:29.95(Materials Science, Multidisciplinary)



Overview of plasma-material interaction experiments on EAST employing MAPES

Ding, F.*; Luo, G.-N.*; Pitts, R.*; Litnovsky, A.*; Gong, X.*; Ding, R.*; Mao, H.*; Zhou, H.*; Wampler, W. R.*; Stangeby, P. C.*; et al.

Journal of Nuclear Materials, 455(1-3), p.710 - 716, 2014/12

 被引用回数:21 パーセンタイル:7.65(Materials Science, Multidisciplinary)

A movable material probe system (Material and Plasma Evaluation System: MAPES) with an independent pumping system and a sample exchange chamber has been developed and installed on a horizontal port of the EAST tokamak for studies of plasma material interaction (PMI). In the 2012 experimental campaign, deposition and erosion were studied for three samples: mock-up of the outer first wall panels (FWPs) in ITER, castellated tungsten, and molybdenum mirrors. The FWPs with carbon deposition layer were exposed to helium plasmas. The maximum erosion rate of the carbon was valuated to be 8 nm/s. The castellated tungsten with rectangular cells and roof-like shaped cells was exposed to deuterium plasmas to compare amount of deposits on the gap surface. The amount of carbon and boron impurities on the gap surface of the roof-like shaped cells were reduced to less than 30% compared with that of the rectangular cells. The molybdenum mirrors of which protective ducts are installed in front were exposed to deuterium plasmas in order to investigate effects of length of the ducts. It was found that the reflectivity of the mirrors with 60 mm-long protective ducts is kept the initial reflectivity.


Corrosion behavior of F82H exposed to high temperature pressurized water with a rotating apparatus

金井 亮彦*; 笠田 竜太*; 中島 基樹; 廣瀬 貴規; 谷川 尚; 榎枝 幹男; 小西 哲之*

Journal of Nuclear Materials, 455(1-3), p.431 - 435, 2014/12

 被引用回数:0 パーセンタイル:100(Materials Science, Multidisciplinary)

The present study reports the compatibility of a reduced-activation ferritic steel F82H exposed to high temperature pressurized water using a rotating disk apparatus at 573 K. Every rotated sample reduces their weight due to water flow. Cross-sectional observations revealed that difference of apparent rotating speed on the microstructural change is limited.


Properties of tritium/helium release from hot isostatic pressed beryllium of various trademarks

Chekushina, L.*; Dyussambayev, D.*; Shaimerdenov, A.*; 土谷 邦彦; 武内 伴照; 河村 弘; Kulsartov, T.*

Journal of Nuclear Materials, 452(1-3), p.41 - 45, 2014/09

 被引用回数:1 パーセンタイル:91.07(Materials Science, Multidisciplinary)



Development of advanced neutron multipliers for DEMO blankets

中道 勝; 金 宰煥

Fusion Science and Technology, 66, p.157 - 162, 2014/08

 被引用回数:1 パーセンタイル:88(Nuclear Science & Technology)

Advanced neutron multipliers and tritium breeders with higher stability at high temperature are desired. Beryllide is one of candidates for the advanced neutron multipliers. To fabricate the beryllide pebbles, a rotating electrode method (REM) was selected. Beryllide electrode fro the REM is necessary. Beryllide electrode has been successfully fabricated by the plasma sintering method. The prototypic beryllide pebbles were successfully fabricated by the REM using this plasma-sintered beryllide electrode. As a advanced tritium breeder, Li$$_{2}$$TiO$$_{3}$$ with excess Li (Li$$_{2+x}$$TiO$$_{3+y}$$) is one of the candidates. For raw material fabarication, synthesis process of Li$$_{2+x}$$TiO$$_{3+y}$$ powder has been developed by the solid phase reaction. From the granulation result by the emulsion method using this raw material, the prototypic pebbles of the Li$$_{2+x}$$TiO$$_{3+y}$$ with less than 5$$mu$$m in grain size and high sphericity, were successfully fabricated.


Honeycomb Palladium catalyst for the oxidation of tritiated hydrocarbons produced in tritium facilities

岩井 保則; 佐藤 克美; 山西 敏彦

Fusion Science and Technology, 66(1), p.214 - 220, 2014/07

 被引用回数:4 パーセンタイル:59.06(Nuclear Science & Technology)

トリチウム化炭化水素の酸化プロセスに適用できるハニカム型パラジウム触媒を開発した。本研究ではパラジウム担持密度が反応速度に与える影響を精査するため2, 5, 10g/Lの三種類のパラジウム密度を持つ触媒を準備した。本研究では炭化水素としてトリチウム化メタンを使用した。ハニカム型パラジウム触媒におけるトリチウム化メタン酸化の総括反応速度係数を空間速度1000から6300h$$^{-1}$$、メタン濃度0.004から100ppm,触媒温度322から673Kの範囲で流通式反応器を用いて評価した。触媒のパラジウム担持密度がトリチウム化メタン酸化の反応速度に与える影響はわずかであった。試験した空間速度の範囲では総括反応速度係数は空間速度に比例した。総括反応速度係数はメタン濃度が10ppm以下ではメタン濃度に依存しなかった。


Engineering validation and engineering design of lithium target facility in IFMIF/EVEDA project

若井 栄一; 近藤 浩夫; 金村 卓治; 古川 智弘; 平川 康; 渡辺 一慶; 井田 瑞穂*; 伊藤 譲; 新妻 重人; 枝尾 祐希; et al.

Fusion Science and Technology, 66(1), p.46 - 56, 2014/07

 被引用回数:4 パーセンタイル:59.06(Nuclear Science & Technology)

EVEDA Lithium Test Loop (ELTL) has been designed and constructed, has operated a liquid lithium flow test facility with the world's highest flow rate and has succeeded in generating a 100-mm-wide and 25-mm-thick free-surface lithium flow along a concave back plate steadily at a high speed of 20 m/s at 300$$^{circ}$$C for the first time in the world. This result will greatly advance the development of an accelerator-based neutron source to high energy and high density, one of the key objectives of the fusion reactor materials development under the BA (Broader Approach) Activities. Recent related engineering validation and engineering design of the lithium facility has been evaluated.


Tensile deformation behavior of plain-woven Tyranno-SA3 CVI-composites at elevated temperatures

小沢 和巳; 野澤 貴史; 豊島 和沖*; 谷川 博康; 檜木 達也*

no journal, , 

SiC/SiC複合材料は核融合炉用先進ブランケットにおいて有力な候補材料である。本研究では、炉材料設計データを蓄積するにあたり、必須にもかかわらず未だ知見の乏しい先進SiC/SiC複合材料の、非照射状態における高温引張変形挙動を評価した。平織構造のTyranno-SA3 SiC繊維で強化しSiCマトリックスを有する複合材料は、現在のところ特に顕著なノッチ効果も認められず、1000$$^{circ}$$C、真空雰囲気下では、比例限度応力(PLS)の130%の負荷で1986時間負荷し続けても破断しない優れた引張ラプチャー特性が示された。

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