Modeling of flux-dependent fluence effect on in-reactor deformation in Zr-alloy tubes

Zr-alloy tubes in reactors suffer from harsh thermal-mechanical-irradiation coupling conditions. Abundant modeling efforts have been devoted to predicting in-reactor deformation but the flux-dependent fluence effect was rarely considered. In this work, a polycrystalline model which considers this effect is proposed, by introducing a flux-dependent factor α which characterizes the trend that higher flux results in more accumulated irradiation defects and therefore higher obstruction on dislocation movement. With this model, the flux-dependent anisotropic deformation behaviors as a function of fluence can be well captured. Particularly, a linear relationship between α and flux is revealed from the experimental results in CANDU reactors.