This work presents a numerical method to assess the relative impact of various microstructural features present in irradiated U-Mo metallic fuels on the effective thermal conductivity. Examples of these features include grain size, nanometer scale intragranular gas bubbles, and larger intergranular gas bubbles. A phase-field model was employed to reconstruct a three-dimensional polycrystalline U-Mo fuel alloy with a given crystal morphology and gas bubble microstructures. The effective thermal conductivity of the polycrystalline with inhomogeneous thermal conductivity was calculated by solving the heat transportation equation. The obtained results are in reasonably good agreement with experimental measurements made on irradiated U-Mo fuel samples containing similar microstructural features. The developed method can be used to predict the thermal conductivity degradation in operating nuclear fuels if the evolution of gas bubble structure (both intragranular and intergranular) is known during operation of the fuel.
Revised: September 30, 2015 |
Published: August 1, 2015
Citation
Hu S.Y., A.M. Casella, C.A. Lavender, D.J. Senor, and D. Burkes. 2015.Assessment of Effective Thermal Conductivity in U-Mo Metallic Fuels with Distributed Gas Bubbles.Journal of Nuclear Materials 462.PNNL-SA-106990.doi:10.1016/j.jnucmat.2015.03.039