Standard UO2fuel pellets used in light water reactors fracture during irradiation due to the large thermal gradient formed across the pellet radius. Over the decades numerous researchers have explored fuel cracking from experimental and modeling points of view.To date, models have been largely been empirical in nature with any mechanistic models employing unrealistically fast ramp rates for normal operation or not accounting for burnup effects. In this work, a mechanistic fuel cracking model using the extended finite element method (XFEM) is employed to explore radial crack formation while including sensitivity analysis due to the randomization of tensile strength within the specimen, the strength randomization criteria, power ramping rates, computational mesh density, maximum power level, and burnup effects. It is found that the uncertainty in the mechanistic modeling approach encompasses the empirically predicted values from three different empirical correlations in almost all cases. This means, that for computationally intensive analyses involving UO2fragmentation, the empirical correlations can be used. However, since the mechanistic calculations bound those of the empirical correlations, confidence can be had in the ability to use the mechanistic approach developed in this work to generate a correlation for fuel types where limited data exists (e.g., doped-UO2, U3Si2).
