<p>To
achieving successfully commercial nuclear fusion energy, fully understanding of
the interaction between plasma particles and plasma facing components is one of
the essential issues. Tungsten, due to good thermal and mechanical properties
such as high thermal conductivity and melting temperature, is one of the most
promising candidates. However, the plasma facing components interacting with
the extreme environmental conditions such as high temperature and radiation may
lead to nanostructure formation, sputtering and erosion that will lead to
material degradation. And these deformations may influence not only properties
of plasma facing components but also might affect the plasma itself. For
example, the contamination of plasma with a few amounts of tungsten, a high Z
element, as a result of erosion or sputtering may cause core plasma cooling
that results in loss of plasma confinement. Additionally, the retention of
hydrogen isotopes, especially tritium, in tungsten is essential issue because
of its radioactivity and market value.</p>
In this study, deuterium trapping in tungsten is
analyzed by molecular dynamics method and the effect of pre-irradiation on
trapping is studied. Non-cumulative studies show that the increase in the
energy of hydrogen isotopes rises the absorption rate, the initial implantation
depth, and the average resting time for initial implantation. Additionally, the
effect of implanted deuterium due to pre-irradiation on the hydrogen isotopes
trapping is analyzed by combining both cumulative and non-cumulative simulations,
and results indicate that while the increase in the pre-irradiation time raises
the absorption rate of deuterium with higher energy than 80 eV, it causes a decrease
the initial implantation depth and the average resting time for initial implantation
because of deuterium-deuterium interactions. Additionally, the
deuterium-deuterium interactions may transfer enough energy to implanted
deuterium to start a motion which may lead to deeper implantation or escaping
from the surface of tungsten. The escaping from surface as a result of
deuterium-deuterium interaction could explain the decrease in accumulation rate
of deuterium while absorption rate rises.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/11288756 |
| Date | 29 November 2019 |
| Creators | Enes Ercikan (8053514) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/MOLECULAR_DYNAMICS_SIMULATION_OF_HYDROGEN_ISOTOPES_TRAPPING_ON_TUNGSTEN_THE_EFFECT_OF_PRE-IRRADIATION/11288756 |
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