Abstract: The silicon carbide（SiC） cladding is a promising accident tolerant cladding in future nuclear reactors. Based on a large number of experimental data, the failure prediction models for monolithic SiC, SiCf-SiC composite and multi-layer SiC cladding were developed with the consideration of size effect. By using of the nuclear fuel performance analysis code, the pin-by-pin fuel performance and cladding failure probability calculation was conducted, and the full-core scale uncertainty evaluation of cladding safety characteristics was completed. In addition, taking the fuel rod with the highest failure risk as an example, the key factors affecting the cladding stress and safety sate were analyzed deeply through Monte Carlo calculation.