Due to the excellent properties of high temperature strength, creep resistance, lower thermal expansion and better irradiation resistance, the silicon carbide is considered as a substitute for the Zircalloy cladding. In this paper, the thermal and mechanical properties of SiC cladding are reviewed firstly. Then the thermophysical properties and mechanical behavior model of the thorium-based fuel and SiC cladding are implemented in FRAPCON-4.0 and FRAPTRAN-1.5 codes. Lastly, the fuel performance of five different types of fuel cladding combinations including two kinds of thorium-based fuel, traditional UO₂ fuel and two kinds of cladding (Zircalloy and two-layer SiC) are analyzed and compared both under the PWR normal operating condition and transient conditions. The results show that under normal or transient conditions, the thorium-based fuel with two-layer SiC cladding is found to have higher safety margin and superior fuel performance than that of the fuels combined with Zircalloy cladding.

由于碳化硅具有高温强度、抗蠕变、较低的热膨胀和较好的抗辐照等优异性能，被认为是锆合金包层的替代品。本文首先综述了碳化硅熔覆层的热力学性能和力学性能。然后在FRAPCON-4.0和FRAPTRAN-1.5代码中实现了钍基燃料和碳化硅包壳的热物理性能和力学行为模型。最后，五种不同类型燃料包壳组合的燃料性能，包括两种钍基燃料，传统的UO ₂燃料和两种包壳（锆合金和两层碳化硅）在压水堆正常工况和瞬态工况下进行了分析和比较。结果表明，在正常或瞬态条件下，发现具有两层 SiC 包层的钍基燃料比结合锆合金包层的燃料具有更高的安全裕度和优越的燃料性能。