Synergism of neutron irradiation and high heat flux presents unique yet critical challenge for SiC-based fuel cladding concepts for LWR’s due to the steep temperature dependence of early swelling in SiC. The primary goal of proposed project is to experimentally verify the multi-physics model of prototypical SiC-based fuel clad to neutron irradiation under high radial heat flux that is relevant to practical LWR fuel operation. Specifically, the project is intended to achieve the following three objectives: 1) Irradiation of tube specimens of prototypical and model SiC-based ATF SiC cladding under a high radial heat flux, 2) Post-irradiation examination of the irradiated tube specimens, and 3) Establish advanced PIE capabilities as the NSUF user infrastructure.