Е-Публикации
Технически университет - София

Abstract: The development of accident-tolerant fuel (ATF) cladding materials is a key priority for enhancing the safety and performance of nuclear reactors, particularly under high-temperature and accident conditions. Traditional Zircaloy-based claddings, while widely used, suffer from oxidation and hydrogen pickup issues at elevated temperatures, motivating the exploration of alternative materials such as FeCrAl alloys and SiC composites. This study presents a comparative mechanical analysis of Zircaloy-4, FeCrAl, and SiC composite claddings under steady-state normal operating conditions. A finite element model was developed in COMSOL Multiphysics 6.2, simulating a hollow cylindrical cladding structure subjected to identical internal and external pressures and a linear thermal gradient representative of reactor environments. Material properties such as Young's modulus, Poisson's ratio, density, and thermal expansion coefficients were assigned based on literature data. The simulation results reveal that while FeCrAl and SiC composites exhibit significantly higher von Mises stresses compared to Zircaloy-4, their superior oxidation resistance and thermal stability offer clear advantages for future reactor applications. These findings suggest that despite the increased mechanical stresses, FeCrAl and SiC composites remain strong candidates for next-generation nuclear fuel cladding designs, provided that appropriate stress management strategies are incorporated.

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