Speaker
Description
Silicon carbide (SiC) has been proposed as a primary coating layer within tri-structured isotropic (TRISO) fuel particles due to its unique properties. While TRISO particles successfully retained most FPs, the release of key radioactive elements such as strontium (Sr) remains a challenge, prompting numerous studies to understand their diffusion mechanisms in SiC. This study investigates the role of hydrogen (H) in the migration of Sr implanted into SiC. The motivation stems from the reactor environment, where SiC is exposed to H generated via radioactive decay and neutron transmutation, as well as other FPs such as Sr. Polycrystalline SiC was first implanted with 300 keV Sr ions to a fluence of 2×10^16 ions/cm² at room temperature (RT) and at 350 °C. Pre-implanted Sr-SiC samples were co-implanted with H ions of 15 keV to a fluence of 1×10^17 ions/cm² under the same conditions. All the samples were annealed at 1000 °C for 5 h. The Sr depth profiles in Sr-SiC and Sr+H-SiC were measured using elastic backscattering spectrometry and Rutherford backscattering spectrometry with different incident particles. Beams of protons (H⁺) and alpha (⁴He⁺) particles were used at energies of 1 MeV (20 µC) and 3 MeV (40 µC), respectively. The measurements were taken at the same geometry of 165 ° for the scattering angle and 10 ° for the tilting angle. The experimental error from 3MeV RBS was calculated to be 6.3%, where Sr depths of 120 nm and 128 nm were obtained from the simulation and experiment, respectively. RT co-implanted samples show a Sr migration toward the surface, and a loss after annealing. In contrast, no Sr migration or loss was detected in the samples co-implanted at 350 °C; both techniques complement these results. The Sr profile has been analyzed with accuracy, and the results are validated using proton and alpha beams of different scattering mechanisms.
| Apply for student award at which level: | PhD |
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| Consent on use of personal information: Abstract Submission | Yes, I ACCEPT |