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Understanding the release of helium atoms from nanochannel tungsten: a molecular dynamics simulation

Journal Article · · Nuclear Fusion
The design of highly radiation-tolerant plasma-facing materials (PFMs) is of great importance for fusion reactors. Our recent experiments have shown that nanochannel tungsten (W) films have clearly superior radiation tolerance properties. In the present work, helium clustering and release from nanochannel tungsten were studied by molecular dynamics simulations. The effects of temperature and vacancy concentration on the helium release from a tungsten cylinder were investigated. Our results show that nanochannel W that consists of thin W cylinders releases He atoms more quickly than bulk W with flat surfaces, thus greatly reducing the He concentration and suppressing the formation and growth of He bubbles, which leads to increased radiation tolerance. Moreover, the micro-structural changes due to increasing He fluence are smaller in nanochannel W than those in bulk W. Although vacancies in nanochannel W will trap He atoms, the nanochannel W also has a stronger tendency to stabilize helium retention than bulk W. The mechanism of helium release from nanochannel W was also examined. The results reported here are beneficial for guiding future work in the design of radiation resistant PFMs.
Research Organization:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Office of Science (SC). Basic Energy Sciences (BES) (SC-22)
Grant/Contract Number:
89233218CNA000001
OSTI ID:
1544702
Alternate ID(s):
OSTI ID: 22929781
Report Number(s):
LA-UR--19-23571
Journal Information:
Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 7 Vol. 59; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English

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