| 초록 |
TRISO-coated fuel particles for high-temperature gas-coold reactors consist of UO2 microspheres coated with multilayers of porous pyrolytic carbon, inner dense pyrolytic carbon, silicon carbide, outer dense pyrolytic carbon. TRISO coatings on ZrO2 surrogate kernels were conducted using a FBCVD method. The influence of the deposition temperature on the properties of the SiC layer were investigated. The SiC layers coated at 1350 oC contained a small amount of excessive carbon, while the stoichiometric composition of SiC coating layer was obtained at 1400oC~1500oC. Moreover, it was verified that the observed acoustic SiC bands in Raman spectra was due to an increased grain boundary caused by fine grains and stacking faults. The 29Si NMR data was revealed regions that could either be interpreted as co-existence of crystallites of several different polytypes, or regions within large disordered structures where the polytype symmetries exist. |
