Evaluation of variability on the thermomechanical response of nitride nuclear fuels through microstructurally explicit models

A two-dimensional (2D) thermo-mechanical finite element model of a cylindrical fuel pellet seen from the longitudinal plane has been run to investigate variability of the thermo-mechanical response (stress field, strain field, grain boundary interaction, temperature distribution) due to microstructure heterogeneity within a Representative Volume Element (RVE). Microstructural information was obtained from sintered ZrN, as a surrogate for PuN, processed under conditions similar to those used in actinide bearing fuels. The 2D RVE obtained from microstructural characterization via Orientation Imaging Microscopy (OIM), which includes pore and grain geometry as well as grain orientation, is surrounded by "effective material" and located at the center of the model to evaluate the effect of stress and temperature gradients on the local fields. This effort is directed towards the formulation of a framework that can be translated into characterization and modeling of actual fuels to improve simulations of fuel performance. Work supported under the Global Nuclear Energy Partnership (GNEP) and the Advanced Fuel Cycle Initiative (AFCI), DOE/NE Agreement # DE-FC07-05ID14654.