Failure analysis of damaged tungsten monoblock components of upper divertor outer target in EAST fusion device

Kang Wang; Ya Xi; Xiang Zan; Dahuan Zhu; Laima Luo; Rui Ding; Yucheng Wu

Nuclear Engineering and Technology (Jun 2024)

Failure analysis of damaged tungsten monoblock components of upper divertor outer target in EAST fusion device

Kang Wang,
Ya Xi,
Xiang Zan,
Dahuan Zhu,
Laima Luo,
Rui Ding,
Yucheng Wu

Affiliations

Kang Wang: Institute of Industry & Equipment Technology, Hefei University of Technology, Hefei, 230009, China
Ya Xi: School of Materials Science and Engineering, Hefei University of Technology, Hefei, 230009, China; Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, SAR, China
Xiang Zan: School of Materials Science and Engineering, Hefei University of Technology, Hefei, 230009, China; National-Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei, 230009, China; Corresponding author. School of Materials Science and Engineering, Hefei University of Technology, Hefei, 230009, China.
Dahuan Zhu: Institute of Plasma Physics, HFIPS, Chinese Academy of Sciences, Hefei, 230031, China
Laima Luo: School of Materials Science and Engineering, Hefei University of Technology, Hefei, 230009, China; National-Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei, 230009, China
Rui Ding: Institute of Plasma Physics, HFIPS, Chinese Academy of Sciences, Hefei, 230031, China
Yucheng Wu: School of Materials Science and Engineering, Hefei University of Technology, Hefei, 230009, China; National-Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei, 230009, China

Journal volume & issue: Vol. 56, no. 6
pp. 2307 – 2316

Abstract

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A melting failure of W monoblock components of the upper divertor outer target in EAST occurred during the plasma campaigns in 2019. The failure characters and microstructure evolution of the failed W monoblock have been well investigated on one string (W436 string). Near the strike point region where heat flux density is highest, macroscopic cracks and severe surface damage such as dimensional change, melting and solidification are visible in several W monoblocks. At the same time, debonding, melting and migration of Cu/CuCrZr cooling tube components introduced fatal damage to the structure and function. The heat-induced microstructure evolution in the rest part has been examined via hardness tests and metallography. From the heat flux surface to the cooling tube, hardness increased gradually and the recrystallized grains could be found in the region with the highest temperature, while recrystallization grains also appear in some W monoblocks near the cooling tube area. The detailed microstructure has been investigated by metallography and EBSD. Such cases in EAST provide experiences on the extreme condition of accidental loss of coolant or higher discharge power in future devices.

Published in Nuclear Engineering and Technology

ISSN: 1738-5733 (Print)
Publisher: Elsevier
Country of publisher: Korea, Republic of
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Nuclear engineering. Atomic power
Website: http://www.journals.elsevier.com/nuclear-engineering-and-technology

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