Improvement of tungsten lifetime by coating with middle melting point materials

2015 Fiscal Year Final Research Report

• Project/Area Number: 26630473
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Nuclear fusion studies
• Research Institution: Osaka University
• Principal Investigator: Ueda Yoshio 大阪大学, 工学(系)研究科(研究院), 教授 (30193816)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: プラズマ対向材料 / タングステン / 中間融点堆積膜 / 蒸気遮蔽効果

Outline of Final Research Achievements

The following results were obtained. (1)Various W materials (pure W, W-2Ta, W-Re) were melted by a pulsed laser with ELM like heat pulses and their melt layer dynamics were studied. It was found that the least droplet ejection by bumping was observed for pure W. (2)W with thin Al coating layers (1 micrometer) was exposed to laser heat pulses and pulsed plasmas. Significant reduction of heat flux to W by evaporation heat of Al and vapor shielding effects by Al vapor was observed. (3)The vapor shielding effects of Be and W were successfully simulated by a newly developed PIC code. (4)W monoblocks for ITER with surface damage (cracking, melting made by pulsed plasmas and electron beam) were tested by cyclic high heat loading by electron beam. Heat flux of 20 MW/m^2 for 10 s was repeatedly applied for simulating slow transient heat pulsed in ITER. It was found that the W monoblocks with surface damage easily showed longitudinal cracks (self castellation).

Free Research Field

プラズマ理工学