Morphological Study of Dispersion Phases in Heterogeneous Waste Form Materials for Ef ficient Nuclear Waste Containment K. Patel, M. Riaz, F. Rabbi, R. Raihan and K. Reifsnider Abstract The ef ficiency of high-level nuclear waste immobilization by incorpo- rating a host phase within a hollandite material structure can be increased by carefully synthesizing the dispersion phases inside the hollandite matrix. Also, estimation of the leaching rate from these nuclear waste forms is critical. Hence, conformal finite elemental model has been developed to study the effect of mor- phology of dispersive phases on diffusive nuclear flux. COMSOL Multi-physics is used as a computational tool to solve a Nernst-Plank Equation to study the diffusion leakage flux. A 2D model is built to identify the effect of volume fractions, surface areas, and different shapes of dispersion phase on the exit flux behavior. The results have indicated that there exists an optimum combination of different parameters such as volume fraction, surface area, position with respect to open boundary, and shape of dispersion phases for immobilization. Keywords Diffusion ⋅ COMSOL ⋅ Nernst-Planck ⋅ Nuclear waste form K. Patel ( ✉ ) ⋅ M. Riaz ( ✉ ) ⋅ K. Reifsnider ( ✉ ) University of Texas at Arlington, Arlington, USA e-mail: krutarthshailes.patel@mavs.uta.edu M. Riaz e-mail: mdriaz.kayser@uta.edu K. Reifsnider e-mail: kenneth.reifsnider@uta.edu F. Rabbi ( ✉ ) ⋅ R. Raihan ( ✉ ) University of Texas at Arlington Research Institute, Arlington, USA e-mail: rabbi@email.sc.edu R. Raihan e-mail: mdrassel.raihan@uta.edu © The Minerals, Metals & Materials Society 2018 The Minerals, Metals & Materials Society, TMS 2018 147th Annual Meeting & Exhibition Supplemental Proceedings, The Minerals, Metals & Materials Series, https://doi.org/10.1007/978-3-319-72526-0_38 399