Advanced fuel performance analysis of multi-layered coated accident-tolerant fuel (ATF) cladding using a coupled multiphysics approach

This study aims to develop the KAFKA code, built on the ABAQUS™ framework, to conduct detailed simulations of Accident Tolerant Fuel (ATF) cladding coated on both the inner and outer surfaces, in order to evaluate the thermal and mechanical performance of coated cladding under different operational conditions. The KAFKA code allows for advanced simulations of fuel rod behaviors, accounting for temperature- and burnup-dependent material properties, fuel swelling, densification, fission gas release, as well as the mechanical responses of cladding and coatings. The results from fully coupled multiphysics modeling demonstrated that Cr and FeCrAl coatings delayed gap closure and reduced hoop stress on the Zr-4 substrate, mitigating failure mechanisms like fatigue, stress corrosion cracking, and creep rupture under steady-state and daily load-following conditions. These findings indicate that the use of coupled multiphysics code enables a more precise evaluation of coated ATF cladding and nuclear fuel performance, contributing to the safer operation of nuclear reactors.