Melt layer dynamics and solidification behavior of tungsten by pulsed heat loading and evalution of surace protection layer

2016 Fiscal Year Final Research Report

• Project/Area Number: 25249132
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Nuclear fusion studies
• Research Institution: Osaka University
• Principal Investigator: Yoshio Ueda 大阪大学, 工学研究科, 教授 (30193816)
• Co-Investigator(Kenkyū-buntansha): 中村 浩章 核融合科学研究所, ヘリカル研究部, 教授 (30311210) ; 帆足 英二 大阪大学, 工学(系)研究科(研究院), 准教授 (40520698) ; 鈴木 哲 国立研究開発法人日本原子力研究開発機構, 核融合研究開発部門 那珂核融合研究所, 研究員 (60354619) ; Lee Heun Tae 大阪大学, 工学(系)研究科(研究院), 助教 (90643297) ; 伊庭野 健造 大阪大学, 工学(系)研究科(研究院), 助教 (80647470) ; 大塚 裕介 大阪大学, 工学(系)研究科(研究院), 助教 (70294048)
• Project Period (FY): 2013-05-31 – 2017-03-31
• Keywords: タングステン / ディスラプション / パルス熱負荷 / 溶融挙動 / 表面保護 / 蒸気遮蔽

Outline of Final Research Achievements

To simulate heat loadings by disruption in tokamak fusion reactors, pulsed laser irradiation experiments to tungsten were performed. Surfaces of melt layers became unstable as surface temperature approaches boiling temperature. As a result, significant surface morphology changes and particle emissions become significant. Melt layer stability for different W materials (pure W, W-Re, W-Ta) showed different behavior as melt layer of W-Ta was lost by bumping while the other two W materials were not. Surface protection layers by Al thin film can effectively protect surface damage. Surface damage (cracking and uneven re-solidified layers) became initiation points for large cracking. Simulation of vapor shielding was performed with a particle simulation code (PIC method). The results showed that Be PFM effectively cools down incoming plasma, but W PFM does not penetrate into edge plasma and does not cool the plasma as effectively as Be PFM.

Free Research Field

核融合理工学