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Title: Motion of W and He atoms during formation of W fuzz

Journal Article · · Nuclear Fusion
 [1];  [1];  [1];  [2];  [3]
  1. Univ. of California, San Diego, CA (United States). Center for Energy Research
  2. Max-Planck Inst. fur Plasmaphysik, Garching, (Germany)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Physics Division

Measurements are conducted to identify the motion of tungsten and helium atoms during the formation of tungsten fuzz. In a first series of experiments the mobility of helium within the growing fuzz was measured by adding 3He to the different stages of plasma exposure under conditions that promoted tungsten fuzz growth. Ion beam analysis was used to quantify the amount of 3He remaining in the samples following the plasma exposure. The results indicate that the retention of helium in bubbles within tungsten is a dynamic process with direct implantation rather than diffusion into the bubbles, best describing the motion of the helium atoms. In the second experiment, an isotopically enriched layer of tungsten (~92.99% 182W) is deposited on the surface of a bulk tungsten sample with the natural abundance of the isotopes. This sample is then exposed to helium plasma at the conditions necessary to support the formation of tungsten 'fuzz'. Depth profiles of the concentration of each of the tungsten isotopes are obtained using secondary ion mass spectrometry (SIMS) before and after the plasma exposure. The depth profiles clearly show mixing of tungsten atoms from the bulk sample toward the surface of the fuzz. Lastly, this supports a physical picture of the dynamic behavior of helium bubbles which, also, causes an enhanced mixing of tungsten atoms.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Nuclear Physics (NP); USDOE Office of Science (SC), Fusion Energy Sciences (FES); European Union (EU)
Grant/Contract Number:
AC05-00OR22725; FG02-07ER54912; SC0018302
OSTI ID:
1435242
Journal Information:
Nuclear Fusion, Vol. 58, Issue 6; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 29 works
Citation information provided by
Web of Science

References (14)

Fuzzy nanostructure growth on Ta/Fe by He plasma irradiation journal July 2016
A full tungsten divertor for ITER: Physics issues and design status journal July 2013
The influence of plasma-surface interaction on the performance of tungsten at the ITER divertor vertical targets journal March 2018
Helium induced nanoscopic morphology on tungsten under fusion relevant plasma conditions journal January 2008
TEM observation of the growth process of helium nanobubbles on tungsten: Nanostructure formation mechanism journal November 2011
Erosion and redeposition experiments in the pisces facility journal February 1987
RESOLNRA: A new program for optimizing the achievable depth resolution of ion beam analysis methods journal April 2008
Sputtering properties of tungsten ‘fuzzy’ surfaces journal August 2011
Quantitatively measuring the influence of helium in plasma-exposed tungsten journal August 2017
The influence of helium on the bulk properties of fusion reactor structural materials journal August 1984
Observation of a helium ion energy threshold for retention in tungsten exposed to hydrogen/helium mixture plasma journal August 2016
Challenges and opportunities of modeling plasma–surface interactions in tungsten using high-performance computing journal August 2015
Experimental mechanistic investigation of the nanostructuring of tungsten with low energy helium plasmas journal December 2016
Self-diffusion in tungsten journal February 1978

Cited By (2)

Plasma-Material-Interaction Research Using PISCES Linear Plasma Devices journal October 2019
The evolution of He nanobubbles in tungsten under fusion-relevant He ion irradiation conditions journal June 2019

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