Dissolution-mediated trapping of deuterium in tungsten: high-flux, high-temperature plasma exposures

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  • UGent - Universiteit Gent

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Abstract

The effect of severe plastic deformation on the deuterium retention in tungsten exposed to high-flux low-energy plasma (flux ~1024 m−2 s−1, energy ~50 eV and fluence up to 5×1025 D/m2) was studied experimentally in a wide temperature range (460-1000 K). The desorption spectra in both reference and plastically-deformed samples were deconvoluted into three contributions associated with the detrapping from dislocations, deuterium-vacancy clusters and pores, respectively. As the exposure temperature increases, the positions of the release peaks do not change but the peak amplitudes are altered as compared to the reference material, due to the presence of dense dislocation networks in the plastically-deformed material. The appearance of blisters detected by scanning electron microscopy and the desorption peak attributed to the release from pores (i.e. deuterium bubbles) were suppressed in the plastically deformed samples at low-temperature exposures, but became the prevailing contribution above 700 K. The observed strong modulation of the deuterium storage in "shallow" and "deep" traps, as well as the reduction of the integral retention above 700 K, suggest that the dislocation network changes its role from "trapping seeds" to "diffusion channels" above a certain temperature. The conclusions of the present work are in line with recent computational assessment based on atomistic and mean field theory calculations.

Details

Original languageEnglish
Pages (from-to)307-315
Number of pages9
JournalJournal of Nuclear Materials
Volume479
DOIs
Publication statusPublished - 9 Jul 2016

Keywords

  • Dislocations, Tungsten, Retention, Hydrogen

ID: 783256