New rate equation model to describe the stabilization of displacement damage by hydrogen atoms during ion irradiation in tungsten

Matic Pecovnik, Etienne Hodille, T Schwarz-Selinger, C. Grisolia, Sabina Markelj

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The effect of deuterium (D) presence on the amount of displacement damage created in tungsten (W) during high-energy W-ion irradiation is investigated. For this purpose, we have performed modelling of experimental results where W was sequentially or simultaneously irradiated by 10.8 MeV W ions and exposed to 300 eV D ions. A novel displacement damage creation and stabilization model was newly developed and introduced into the MHIMS-Reservoir (Migration of Hydrogen Isotopes in MaterialS) code. It employs macroscopic rate equations (MREs) for solving the evolution of solute and trapped D concentrations in the material. The new displacement damage creation and stabilization model is based on spontaneous recombination of Frenkel pairs and stabilization of defects that are occupied by D atoms. By using the new model, we could successfully replicate the measured D depth profiles and D thermal desorption data, where a higher defect concentration was observed when D was present during W irradiation as compared to when no D was present. For this we utilized parameters, which include the number of distinct defect types, the de-trapping energies of their fill-levels, their saturation concentrations and their probability for stabilization if they contain a D during the W-ion irradiation. To successfully replicate the experimental results three distinct defect types were needed with several fill-levels. By comparing the de-trapping energies of the defect fill-levels with data available from the literature, the defect types were identified as single-vacancies, small vacancy clusters and large vacancy clusters. The effect of D presence was found to be largest in single vacancies as its concentration increased by about a factor of three, while the concentration of small vacancy clusters increased by about a factor of two. Large vacancy clusters were found to be largely unaffected as they showed very little increase in concentration when D was present
Originalspråkengelska
Artikelnummer036024
TidskriftNuclear Fusion
Volym60
Utgåva3
Antal sidor18
ISSN0029-5515
DOI
StatusPublicerad - mar 2020
MoE-publikationstypA1 Tidskriftsartikel-refererad

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