Microstructure of TRISO coated particles from the AGR-1 experiment: SiC grain size and grain boundary character

Kirchhofer, Rita; Hunn, John D.; Demkowicz, Paul A.; Cole, James I.; Gorman, Brian P.

doi:10.1016/j.jnucmat.2012.08.052

Cited by 56 publications

(68 citation statements)

References 22 publications

(32 reference statements)

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“…The EBSD maps did not exhibit an indication for a pronounced texture in any of the specimens, which was also found within other studies using EBSD analysis for TRISO fuel [23][24][25]. The {111} pole figures in Fig.…”

Section: Microstructural Characterisationsupporting

confidence: 86%

Comparison study of silicon carbide coatings produced at different deposition conditions with use of high temperature nanoindentation

et al. 2016

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The elastic modulus and hardness of different silicon carbide (SiC) coatings in tristructural-isotropic (TRISO) fuel particles were measured by in situ high temperature nanoindentation up to 500°C. Three samples fabricated by different research institutions were compared. Due to varied fabrication parameters the samples exhibited different grain sizes and one contained some visible porosity. However, irrespective of the microstructural features in each case the hardness was found to be very similar in the three coatings around 35 GPa at room temperature. Compared with the significantly coarser grained bulk CVD SiC, the drop in hardness with temperature was less pronounced for TRISO particles, suggesting that the presence of grain boundaries impeded plastic deformation. The elastic modulus differed for the three TRISO coatings with room temperature values ranging from 340 to 400 GPa. With increasing measurement temperature the elastic modulus showed a continuous decrease.

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Section: Microstructural Characterisationsupporting

confidence: 86%

Comparison study of silicon carbide coatings produced at different deposition conditions with use of high temperature nanoindentation

et al. 2016

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“…The lost fraction was most likely situated in or near the original and newly formed grain boundaries, while out-diffusion of krypton from deep inside these crystal-lites does not occur. The apparently large contribution of the newly formed grain boundaries is surprising, as it would be expected, that their high degree of tortuosity should have hindered effective out-diffusion [12,13].…”

Section: Resultsmentioning

confidence: 99%

Influence of radiation damage on krypton diffusion in silicon carbide

Friedland

Hlatshwayo

Berg

et al. 2015

Nuclear Instruments and Methods in Physics Research Section B:

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Diffusion of krypton in poly and single crystalline silicon carbide is investigated and compared with the previously obtained results for xenon, which pointed to a different diffusion mechanism than observed for chemically active elements. For this purpose 360 keV krypton ions were implanted in commercial 6H-SiC and CVD-SiC wafers at room temperature, 350 °C and 600 °C. Width broadening of the implantation profiles and krypton retention during isochronal and isothermal annealing up to temperatures of 1400 °C was determined by RBS-analysis, whilst in the case of 6H-SiC damage profiles were simultaneously obtained by α-particle channelling. Little diffusion and no krypton loss was detected in the initially amorphized and eventually recrystallized surface layer of cold implanted 6H-SiC during annealing up to 1200 °C. Above that temperature thermal etching of the implanted surface became increasingly important. No diffusion or krypton loss is detected in the hot implanted 6H-SiC samples during annealing up to 1400 °C. Radiation damage dependent grain boundary diffusion is observed at 1300 C in CVD-SiC. The results seem to indicate, that the chemically inert noble gas atoms do not form defect-impurity complexes, which strongly influence the diffusion behaviour of other diffusors in silicon carbide.

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“…Silver diffusion in CVD-SiC is now well understood. It is mainly due to grain boundary diffusion [10,[16][17]. However the influence of grain boundary structure on diffusion is still unclear [16][17].…”

Section: Introductionmentioning

confidence: 99%