Since the accident at the Fukushima Daiichi Nuclear Power Station, universities, regulators, vendors, utilities, and laboratories have increased efforts to understand fuel behavior and to enhance the accident tolerance of light water reactors (LWRs). One focus is the development of improved fuels and cladding for LWRs that can tolerate a loss of cooling for a considerably longer time compared to current technology. This paper presents early results in developing and applying thermal and mechanical models for two materials that may have promise: U-Si for fuel, and FeCrAl for cladding. DOE’s Nuclear Energy Advanced Modeling and Simulation Program is undertaking this development in coordination with the experimental program underway in DOE’s Advanced Fuels Campaign, and the paper discusses the coordinated effort. The paper also reviews early results using BISON to compare normal operation behavior using the new models with the standard UO2/Zr-4 system.