Thermal diffusivity and thermal conductivity of SiC composite tubes: the effects of microstructure and irradiation

[摘要] Cladding thermal conductivity is an important physical property in assessing the performance of sili-con carbide (SiC)-cladded fuels for nuclear reactors. However, there is a significant lack of reliable data, particularly for irradiated materials, because the geometry complicates the measurement. This study in-vestigates the thermal diffusivity of coupons with a curvature, machined from SiC fiber-reinforced SiC matrix composite tubes, with and without neutron irradiation under light water reactor-relevant tem-perature and dose conditions. The tested materials included full composite and duplex SiC composite tubes. The measurements were conducted using a modern flash diffusivity apparatus. The analyzed area on the specimen during diffusivity testing was reduced for improved measurement accuracy due to sam-ple curvature. Post-irradiation measurements showed that the effects of neutron irradiation on thermal conductivity (e.g. thermal defect resistivity) are different between SiC composite plates versus tubes. The difference was explained by higher matrix density of the tube than the plate. This study provides reliable thermal properties of prototypic SiC composite tubes useful for fuel performance modeling of SiC-based cladding. (c) 2021 Elsevier B.V. All rights reserved.

[发布日期] 2021-12-15

[关键词] SiC;Thermal properties;Irradiation;Cladding