TY  - JOUR
AU  - Qu, Shilian
AU  - Sun, Hao
AU  - Kreter, Arkadi
AU  - Yuan, Yue
AU  - Cheng, Long
AU  - Huang, Zhengxing
AU  - Xu, Ben
AU  - Chen, Wanqi
AU  - Cui, Wei
AU  - Tang, Zhenan
AU  - Jia, Yuzhen
AU  - Lian, YouYun
AU  - Liu, Xiang
AU  - Liu, Wei
TI  - Degradation of thermal conductivity of the damaged layer of tungsten irradiated by helium-plasma
JO  - Fusion engineering and design
VL  - 137
SN  - 0920-3796
CY  - New York, NY [u.a.]
PB  - Elsevier
M1  - FZJ-2019-01300
SP  - 97 - 103
PY  - 2018
AB  - Pure tungsten samples were irradiated by helium plasma in the linear plasma device PSI-2 with an ion energy of 40 eV and a flux of 1.1 × 1022 m−2s−1. The irradiation temperature was from 523 K to 773 K and the fluence was from 1.0 × 1025 to 1.0 × 1026 m−2. A damaged layer of 10 nm thickness was formed on the sample surface with a destroyed crystalline structure. Helium-bubbles and surface modification in nanoscale were observed. Thermal conductivities of the ultra-thin damaged layers were measured by the transient thermoreflectance technique. Result shows that the thermal conductivity reduced two orders of magnitude compared to the bulk value and decreased with increasing irradiation temperature and fluence. Moreover, the helium-irradiated samples were exposed to ELM-like heat load produced by electron beam on EMS-60. The pulse length was 1 ms and each sample was exposed to 5 pulses. Melting occurred under power density of 1.7 GW m−2. As the thermal conductivity of the damaged layer decreased, the molten bath of the irradiated sample deepened. The degraded thermal conductivity led to a lower melting threshold. The characterization of the thermal conductivity of the damaged layer induced by the plasma irradiation is a promising way to estimate the damage level, as well as the failure threshold, of the plasma facing components.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000454466000015
DO  - DOI:10.1016/j.fusengdes.2018.08.014
UR  - https://juser.fz-juelich.de/record/860627
ER  -