A MOOSE (Multiphysics Object-Oriented Simulation Environment) based application, TREX, has been developed for modeling and simulation of advanced ceramic waste forms at multiple length scales. A method was developed for incorporating microstructural details at the mesoscale and computing effective material properties that can then be applied at the engineering scale capable of modeling the entire waste form. The work described includes the creation of Kernel, Material, and Postprocessor objects necessary to model the advanced ceramic waste form. Using these developed tools, the diffusion of cesium was modeled in a hollandite waste form. Experimental data and first principle calculations taken from the literature were used to inform models of the hollandite material properties.