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Title: Properties of Vacancy Complexes with Hydrogen and Helium Atoms in Tungsten from First Principles

Tungsten and its alloys are the primary candidate materials for plasma-facing components in fusion reactors. The material is exposed to high-energy neutrons and the high flux of helium and hydrogen atoms. In this paper, we have studied the properties of vacancy clusters and their interaction with H and He in W using density functional theory. Convergence of calculations with respect to modeling cell size was investigated. It is demonstrated that vacancy cluster formation energy converges with small cells with a size of 6 × 6 × 6 (432 lattice sites) enough to consider a microvoid of up to six vacancies with high accuracy. Most of the vacancy clusters containing fewer than six vacancies are unstable. Introducing He or H atoms increases their binding energy potentially making gas-filled bubbles stable. Finally, according to the results of the calculations, the H 2 molecule is unstable in clusters containing six or fewer vacancies.
Authors:
 [1] ;  [1] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-05CH11231; SC0008875
Type:
Accepted Manuscript
Journal Name:
Fusion Science and Technology
Additional Journal Information:
Journal Volume: 71; Journal Issue: 1; Journal ID: ISSN 1536-1055
Publisher:
American Nuclear Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24); USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; binding energy; plasma-facing material; hydrogen and helium in tungsten
OSTI Identifier:
1340451