The mobility of small vacancy/helium complexes in tungsten and its impact on retention in fusion-relevant conditions
Abstract Tungsten is a promising plasma facing material for fusion reactors. Despite many favorable properties, helium ions incoming from the plasma are known to dramatically affect the microstructure of tungsten, leading to bubble growth, blistering, and/or to the formation of fuzz. In order to dev...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2017-05-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-017-02428-2 |
| _version_ | 1818343940396417024 |
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| author | Danny Perez Luis Sandoval Sophie Blondel Brian D. Wirth Blas P. Uberuaga Arthur F. Voter |
| author_facet | Danny Perez Luis Sandoval Sophie Blondel Brian D. Wirth Blas P. Uberuaga Arthur F. Voter |
| author_sort | Danny Perez |
| collection | DOAJ |
| description | Abstract Tungsten is a promising plasma facing material for fusion reactors. Despite many favorable properties, helium ions incoming from the plasma are known to dramatically affect the microstructure of tungsten, leading to bubble growth, blistering, and/or to the formation of fuzz. In order to develop mitigation strategies, it is essential to understand the atomistic processes that lead to bubble formation and subsequent microstructural changes. In this work, we use large-scale Accelerated Molecular Dynamics simulations to investigate small (N = 1,2) V N He M vacancy/helium complexes, which serve as the nuclei for larger helium bubble growth, over timescales reaching into the milliseconds under conditions typical of the operation of fusion reactors. These complexes can interconvert between different I L V N+L He M variants via Frenkel pair nucleation (leading to the creation of a additional vacancy/interstitial pair) and annihilation events; sequences of these events can lead to net migration of these embryonic bubbles. The competition between nucleation and annihilation produces a very complex dependence of the diffusivity on the number of heliums. Finally, through cluster dynamics simulations, we show that diffusion of these complexes provides an efficient pathway for helium release at fluxes expected in fusion reactors, and hence that accounting for the mobility of these complexes is crucial. |
| first_indexed | 2024-12-13T16:38:34Z |
| format | Article |
| id | doaj.art-865b53dcbd5f40d9af65e81f5f59712d |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-13T16:38:34Z |
| publishDate | 2017-05-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-865b53dcbd5f40d9af65e81f5f59712d2022-12-21T23:38:20ZengNature PortfolioScientific Reports2045-23222017-05-01711910.1038/s41598-017-02428-2The mobility of small vacancy/helium complexes in tungsten and its impact on retention in fusion-relevant conditionsDanny Perez0Luis Sandoval1Sophie Blondel2Brian D. Wirth3Blas P. Uberuaga4Arthur F. Voter5Theoretical Division T-1, Los Alamos National LaboratoryTheoretical Division T-1, Los Alamos National LaboratoryDepartment of Nuclear Engineering, University of TennesseeDepartment of Nuclear Engineering, University of TennesseeMaterials Science and Technology MST-8, Los Alamos National LaboratoryTheoretical Division T-1, Los Alamos National LaboratoryAbstract Tungsten is a promising plasma facing material for fusion reactors. Despite many favorable properties, helium ions incoming from the plasma are known to dramatically affect the microstructure of tungsten, leading to bubble growth, blistering, and/or to the formation of fuzz. In order to develop mitigation strategies, it is essential to understand the atomistic processes that lead to bubble formation and subsequent microstructural changes. In this work, we use large-scale Accelerated Molecular Dynamics simulations to investigate small (N = 1,2) V N He M vacancy/helium complexes, which serve as the nuclei for larger helium bubble growth, over timescales reaching into the milliseconds under conditions typical of the operation of fusion reactors. These complexes can interconvert between different I L V N+L He M variants via Frenkel pair nucleation (leading to the creation of a additional vacancy/interstitial pair) and annihilation events; sequences of these events can lead to net migration of these embryonic bubbles. The competition between nucleation and annihilation produces a very complex dependence of the diffusivity on the number of heliums. Finally, through cluster dynamics simulations, we show that diffusion of these complexes provides an efficient pathway for helium release at fluxes expected in fusion reactors, and hence that accounting for the mobility of these complexes is crucial.https://doi.org/10.1038/s41598-017-02428-2 |
| spellingShingle | Danny Perez Luis Sandoval Sophie Blondel Brian D. Wirth Blas P. Uberuaga Arthur F. Voter The mobility of small vacancy/helium complexes in tungsten and its impact on retention in fusion-relevant conditions Scientific Reports |
| title | The mobility of small vacancy/helium complexes in tungsten and its impact on retention in fusion-relevant conditions |
| title_full | The mobility of small vacancy/helium complexes in tungsten and its impact on retention in fusion-relevant conditions |
| title_fullStr | The mobility of small vacancy/helium complexes in tungsten and its impact on retention in fusion-relevant conditions |
| title_full_unstemmed | The mobility of small vacancy/helium complexes in tungsten and its impact on retention in fusion-relevant conditions |
| title_short | The mobility of small vacancy/helium complexes in tungsten and its impact on retention in fusion-relevant conditions |
| title_sort | mobility of small vacancy helium complexes in tungsten and its impact on retention in fusion relevant conditions |
| url | https://doi.org/10.1038/s41598-017-02428-2 |
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