The goal of this project is to develop and demonstrate an additive manufacturing approach to fabricate nonintrusive and spatially resolved sensors for in-pile thermal conductivity measurement through direct sensor printing onto fuel components or fuel surrogates. Thermal conductivity is one of the most important fuel properties driving heat transfer performance as well as temperature distributions of the fuel assembly. Thermal conductivity is determined by materials’ physical structure, chemical composition, and thermodynamic state, which can be strongly affected by a variety of physical processes in nuclear fuels, such as species diffusion, neutron capture, and microstructure evolution.