Thermal transport in selected ceramic materials for potential application as inert matrix fuel or thermal barrier coating using atomic level simulation

Thermal management is a critical issue in nuclear reactor and thermal barrier coating applications. Current research for next-gen nuclear fuel is looking into materials to provide uranium-free alternate with high thermal conductivity, whereas thermal barrier coating research is in need of low thermal conductivity materials. In this work, an understanding of various structural factors on thermal conductivity using atomic level simulation, is presented.;Thermal conductivity is a key parameter in the selection of nuclear fuel. Next gen nuclear fuel is suggested as to improve the efficiency of the nuclear fuel and make it environment friendly. Next-gen nuclear fuel is called as inert matrix fuel. Thermal conductivity of two potential materials (MgO-Nd 2Zr2O7:NDZ and MgAl2O4) is characterized using molecular dynamics simulation.;In a composite system, interfaces play a dominant role in governing thermal conductivity of the system. To characterize the interface effects, very fine 2-D textured grains (<10 nm) are build. Homogeneous interface simulations showed the dominance of interface effects on grains. Extension to bigger grain sizes showed good compatibility of the simulation data with the experimental dependence of grain size.;In addition, MgAl2O4, a spinel system, has been characterized also for its potential application as an inert matrix. Since system undergoes cation anti-site inverted state under irradiation, thermal conductivity as a function of inversion is characterized. It has been shown that, thermal conductivity remains invariant under inversion. In the process of characterizing thermal conductivity, thermal expansion, bulk modulus and elastic properties are also illustrated.;Another key area for heat management is thermal barrier coating application. Thermal conductivity of a layered perovskite material, Bi4Ti 3O12 (BIT) belonging to Aurivillius family, is characterized. The effect of layers (Bi2O2 layer and perovskite layer) on the thermal transport of BIT is characterized by changing the mass of the layers under selected scenarios. The findings of the study suggested an effect of disparity between layers on the thermal conductivity of BIT in the through direction but limited role in the other directions.