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Title: Modeling Helium Segregation to the Surfaces of Plasma-Exposed Tungsten as a Function of Temperature and Surface Orientation

Abstract

We provide a description of the dependence on surface crystallographic orientation and temperature of the segregation of helium implanted with energies consistent with low-energy plasma exposure to tungsten surfaces. Here, we describe multiscale modeling results based on a hierarchical approach to scale bridging that incorporates atomistic studies based on a reliable interatomic potential to parameterize a spatially dependent drift-diffusion-reaction cluster-dynamics code. An extensive set of molecular dynamics (MD) simulations has been performed at 933 K and/or 1200 K to determine the probabilities of desorption and modified trap mutation that occurs as small, mobile Hen (1 ≤ n ≤ 7) clusters diffuse from the near-surface region toward surfaces of varying crystallographic orientation due to an elastic interaction force that provides the thermodynamic driving force for surface segregation. These near-surface cluster dynamics have significant effects on the surface morphology, the near-surface defect structures, and the amount of helium retained in the material upon plasma exposure, for which we have developed an extensive MD database of cumulative evolution during high-flux helium implantation at 933 K, which we compare to our properly parameterized cluster-dynamics model. This validated model is then used to evaluate the effects of temperature on helium retention and subsurface helium clustering.

Authors:
 [1];  [2];  [3];  [3];  [4]
  1. University of Tennessee, Department of Nuclear Engineering, Knoxville, Tennessee 37996; Oak Ridge National Laboratory, Computer Sciences and Mathematics Division, Oak Ridge, Tennessee 37831
  2. University of Missouri, Department of Chemical Engineering, Columbia, Missouri 65211; University of Missouri, Nuclear Engineering Program, Columbia, Missouri 65211
  3. University of Massachusetts, Department of Chemical Engineering, Amherst, Massachusetts 01003-9303
  4. University of Tennessee, Department of Nuclear Engineering, Knoxville, Tennessee 37996; Oak Ridge National Laboratory, Fusion and Materials for Nuclear Systems Division, Oak Ridge, Tennessee 37831
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory-National Energy Research Scientific Computing Center
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1524075
DOE Contract Number:  
SC0008875; AC02-06CH11231; AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Fusion Science and Technology
Additional Journal Information:
Journal Volume: 71; Journal Issue: 1; Journal ID: ISSN 1536-1055
Publisher:
American Nuclear Society
Country of Publication:
United States
Language:
English

Citation Formats

Blondel, Sophie, Hammond, Karl D., Hu, Lin, Maroudas, Dimitrios, and Wirth, Brian D. Modeling Helium Segregation to the Surfaces of Plasma-Exposed Tungsten as a Function of Temperature and Surface Orientation. United States: N. p., 2017. Web. doi:10.13182/FST16-112.
Blondel, Sophie, Hammond, Karl D., Hu, Lin, Maroudas, Dimitrios, & Wirth, Brian D. Modeling Helium Segregation to the Surfaces of Plasma-Exposed Tungsten as a Function of Temperature and Surface Orientation. United States. doi:10.13182/FST16-112.
Blondel, Sophie, Hammond, Karl D., Hu, Lin, Maroudas, Dimitrios, and Wirth, Brian D. Mon . "Modeling Helium Segregation to the Surfaces of Plasma-Exposed Tungsten as a Function of Temperature and Surface Orientation". United States. doi:10.13182/FST16-112.
@article{osti_1524075,
title = {Modeling Helium Segregation to the Surfaces of Plasma-Exposed Tungsten as a Function of Temperature and Surface Orientation},
author = {Blondel, Sophie and Hammond, Karl D. and Hu, Lin and Maroudas, Dimitrios and Wirth, Brian D.},
abstractNote = {We provide a description of the dependence on surface crystallographic orientation and temperature of the segregation of helium implanted with energies consistent with low-energy plasma exposure to tungsten surfaces. Here, we describe multiscale modeling results based on a hierarchical approach to scale bridging that incorporates atomistic studies based on a reliable interatomic potential to parameterize a spatially dependent drift-diffusion-reaction cluster-dynamics code. An extensive set of molecular dynamics (MD) simulations has been performed at 933 K and/or 1200 K to determine the probabilities of desorption and modified trap mutation that occurs as small, mobile Hen (1 ≤ n ≤ 7) clusters diffuse from the near-surface region toward surfaces of varying crystallographic orientation due to an elastic interaction force that provides the thermodynamic driving force for surface segregation. These near-surface cluster dynamics have significant effects on the surface morphology, the near-surface defect structures, and the amount of helium retained in the material upon plasma exposure, for which we have developed an extensive MD database of cumulative evolution during high-flux helium implantation at 933 K, which we compare to our properly parameterized cluster-dynamics model. This validated model is then used to evaluate the effects of temperature on helium retention and subsurface helium clustering.},
doi = {10.13182/FST16-112},
journal = {Fusion Science and Technology},
issn = {1536-1055},
number = 1,
volume = 71,
place = {United States},
year = {2017},
month = {1}
}

Works referenced in this record:

Tungsten surface evolution by helium bubble nucleation, growth and rupture
journal, June 2013


Simulation of Helium Behavior Near Subsurface Prismatic Dislocation Loops in Tungsten
journal, January 2017

  • Hammond, Karl D.; Ferroni, Francesco; Wirth, Brian D.
  • Fusion Science and Technology, Vol. 71, Issue 1
  • DOI: 10.13182/FST16-110

Nosé–Hoover chains: The canonical ensemble via continuous dynamics
journal, August 1992

  • Martyna, Glenn J.; Klein, Michael L.; Tuckerman, Mark
  • The Journal of Chemical Physics, Vol. 97, Issue 4
  • DOI: 10.1063/1.463940

Diffusion and transformation kinetics of small helium clusters in bulk tungsten
journal, July 2014


Nanostructure formation on tungsten exposed to low-pressure rf helium plasmas: A study of ion energy threshold and early stage growth
journal, August 2011


Helium concentration in tungsten nano-tendril surface morphology using Elastic Recoil Detection
journal, July 2013


Comparison of tungsten nano-tendrils grown in Alcator C-Mod and linear plasma devices
journal, July 2013


Dynamics of small mobile helium clusters near tungsten surfaces
journal, August 2014


Formation of Nanostructured Tungsten with Arborescent Shape due to Helium Plasma Irradiation
journal, January 2006

  • Takamura, Shuichi; Ohno, Noriyasu; Nishijima, Dai
  • Plasma and Fusion Research, Vol. 1
  • DOI: 10.1585/pfr.1.051

Thermal stability of helium–vacancy clusters in iron
journal, April 2003

  • Morishita, K.; Sugano, R.; Wirth, B. D.
  • Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 202
  • DOI: 10.1016/S0168-583X(02)01832-3

Interactions of mobile helium clusters with surfaces and grain boundaries of plasma-exposed tungsten
journal, May 2014

  • Hu, Lin; Hammond, Karl D.; Wirth, Brian D.
  • Journal of Applied Physics, Vol. 115, Issue 17
  • DOI: 10.1063/1.4874675

An improved N -body semi-empirical model for body-centred cubic transition metals
journal, July 1987


MD simulations of onset of tungsten fuzz formation under helium irradiation
journal, May 2013

  • Lasa, A.; Henriksson, K. O. E.; Nordlund, K.
  • Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 303
  • DOI: 10.1016/j.nimb.2012.11.029

Tungsten nano-tendril growth in the Alcator C-Mod divertor
journal, March 2012


Effects of interatomic potential on He bubble creation by cascades in α-iron
journal, March 2008

  • Yang, L.; Zu, X. T.; Wang, Z. G.
  • Journal of Applied Physics, Vol. 103, Issue 6
  • DOI: 10.1063/1.2902503

Fast Parallel Algorithms for Short-Range Molecular Dynamics
journal, March 1995


Crystal orientation effects on helium ion depth distributions and adatom formation processes in plasma-facing tungsten
journal, October 2014

  • Hammond, Karl D.; Wirth, Brian D.
  • Journal of Applied Physics, Vol. 116, Issue 14
  • DOI: 10.1063/1.4897419

A simple empirical N -body potential for transition metals
journal, July 1984


A new interatomic potential function for helium
journal, January 1968


Challenges and opportunities of modeling plasma–surface interactions in tungsten using high-performance computing
journal, August 2015


TEM observation of the growth process of helium nanobubbles on tungsten: Nanostructure formation mechanism
journal, November 2011


Semiempirical, Quantum Mechanical Calculation of Hydrogen Embrittlement in Metals
journal, April 1983


Canonical dynamics: Equilibrium phase-space distributions
journal, March 1985


Formation process of tungsten nanostructure by the exposure to helium plasma under fusion relevant plasma conditions
journal, August 2009


Microscopic damage of tungsten exposed to deuterium–helium mixture plasma in PISCES and its impacts on retention property
journal, August 2011


Molecular dynamics simulations on the effect of sub-surface helium bubbles on the sputtering yield of tungsten
journal, July 2013


Molecular-dynamics analysis of mobile helium cluster reactions near surfaces of plasma-exposed tungsten
journal, October 2015

  • Hu, Lin; Hammond, Karl D.; Wirth, Brian D.
  • Journal of Applied Physics, Vol. 118, Issue 16
  • DOI: 10.1063/1.4933393

A unified formulation of the constant temperature molecular dynamics methods
journal, July 1984

  • Nosé, Shuichi
  • The Journal of Chemical Physics, Vol. 81, Issue 1
  • DOI: 10.1063/1.447334

Helium impurity transport on grain boundaries: Enhanced or inhibited?
journal, June 2015


Molecular dynamics simulation of the effect of sub-surface helium bubbles on hydrogen retention in tungsten
journal, July 2013


Interatomic potentials for simulation of He bubble formation in W
journal, January 2013


A density functional theory assessment of the clustering behaviour of He and H in tungsten
journal, April 2009


Molecular dynamics simulations of helium cluster formation in tungsten
journal, March 2006

  • Henriksson, K. O. E.; Nordlund, K.; Keinonen, J.
  • Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 244, Issue 2
  • DOI: 10.1016/j.nimb.2005.10.020

Helium induced nanoscopic morphology on tungsten under fusion relevant plasma conditions
journal, January 2008