  In this work we developed a practical and general modeling approach for
thermal conductivity of metals and metal alloys that integrates ab initio and
semiempirical physics-based models to maximize the strengths of both
techniques. The approach supports creation of highly accurate, mechanistic, and
extensible thermal conductivity modeling of alloys. The model was demonstrated
on {\alpha}-U and U-rich U-Zr and U-Mo alloys, which are potential fuels for
advanced nuclear reactors. The safe use of U-based fuels requires quantitative
understanding of thermal transport characteristics of the fuel. The model
incorporated both phonon and electron contributions, displayed good agreement
with experimental data over a wide temperature range, and provided insight into
the different physical factors that govern the thermal conductivity under
different temperatures. This model is general enough to incorporate more
complex effects like additional alloying species, defects, transmutation
products, and noble gas bubbles to predict the behavior of complex metallic
alloys like U-alloy fuel systems under burnup.
