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Title: The thermodynamic and kinetic interactions of He interstitial clusters with bubbles in W

Due to its enviable properties, tungsten is a leading candidate plasma facing material in nuclear fusion reactors. But, like many other metals, tungsten is known to be affected by the high doses of helium atoms incoming from the plasma. Indeed, the implanted interstitial helium atoms cluster together and, upon reaching a critical cluster size, convert into substitutional nanoscale He bubbles. These bubbles then grow by absorbing further interstitial clusters from the matrix. This process can lead to deleterious changes in microstructure, degradation of mechanical properties, and contamination of the plasma. In order to better understand the growth process, we use traditional and accelerated molecular dynamics simulations to investigate the interactions between interstitial He clusters and pre-existing bubbles. These interactions are characterized in terms of thermodynamics and kinetics. We also show that the proximity of the bubble leads to an enhancement of the trap mutation rate and, consequently, to the nucleation of satellite bubbles in the neighborhood of existing ones. Finally, we uncover a number of mechanisms that can lead to the subsequent annihilation of such satellite nanobubbles.
Authors:
ORCiD logo [1] ;  [1] ; ORCiD logo [2] ; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology MST-8
Publication Date:
Report Number(s):
LA-UR-16-22259
Journal ID: ISSN 0021-8979; TRN: US1800624
Grant/Contract Number:
AC52-06NA25396; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 119; Journal Issue: 20; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC). Advanced Scientific Computing Research (ASCR) (SC-21); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Material Science; Magnetic Fusion Energy
OSTI Identifier:
1414089
Alternate Identifier(s):
OSTI ID: 1254522