Abstract
Retention of hydrogen isotopes is a critical concern for operating fusion reactors as retained tritium both activates components and removes scarce fuel from the fuel cycle. Radiation-induced displacement damage in SiC influences the retention of hydrogen isotopes compared to pristine SiC. Deuterium retention in neutron irradiated high purity SiC has been compared to different microstructures of non-irradiated high purity SiC using thermal desorption spectroscopy after gas charging and low energy ion implantation. Experimental results show lower deuterium retention in single crystal SiC than in polycrystal SiC indicating that grain boundaries are key trapping features in unirradiated SiC. Deuterium is released at lower temperatures in neutron irradiated polycrystal SiC compared to pristine polycrystal SiC, suggesting weaker trapping by radiation-induced defects compared to grain boundary trapping sites in the pristine materials. Low energy ion implantation caused a high deuterium release temperature, highlighting the sensitivity of deuterium release behaviour to radiation defect characteristics. First principles calculations have been conducted to identify energetically favourable trapping sites in SiC at the HABcVSi and HTSiVC complexes, and migration barriers between interstitial sites. This helps interpret experimental results and derive effective diffusivity of hydrogen isotopes in SiC in the presence of vacancies.
| Original language | English |
|---|---|
| Article number | 1534820 |
| Journal | Frontiers in Nuclear Engineering |
| Volume | 4 |
| DOIs | |
| State | Published - 2025 |
Funding
The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. AJL was supported by the Royal Academy of Engineering under the Research Fellowship programme. This work was partially supported by the US Department of Energy, Office of Fusion Energy Sciences, Fusion Materials Program and Early Career Research Program under contact DE-AC05-00OR22725 with UT-Battelle LLC. A portion of this research used resources at the HFIR, a DOE Office of Science User Facility operated by ORNL. This work has been part-funded by the EPSRC Energy Programme [grant number EP/W006839/1]. This work has been part-funded by STEP, a UKAEA programme to design and build a prototype fusion energy plant and a path to commercial fusion. DNM and IFV would like to thank EUROfusion support for the use of high-performing computing machines: MARCONI and LEONARDO in Bologna, Italy. This manuscript has been coauthored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-publicaccess-plan ).
Keywords
- density function theory (DFT)
- hydrogen isotope retention
- neutron radiation damage
- silicon carbide
- thermal desorption spectroscopy (TDS)