Thermal Conductivity for U-Zr-Ce Metallic Fuels

In Korea, a sodium-cooled fast reactor (SFR) has been adopted. U-Zr and U-Pu-Zr metallic fuel are used in the SFR. KAERI has designed metallic fuels and evaluated their performance in a SFR. Recently, the fuel fabrication technology has also started to be developed. The spent fuel is transformed into new fuel materials through a pyroprocess. An electrorefining process produces U, Pu, and minor actinides (MA) along with a carryover of rare earth (RE) elements. Thermophysical properties of metallic fuels for a SFR could be varied by an influence of the RE. The thermal conductivity is one of the most important parameters dominating the in-reactor performance of these fuels. In this work, we have investigated the variation of the thermal conductivity for U-Zr fuel containing Ce. By examining the microstructural characteristics of U-Zr-Ce, the thermal conductivity of the alloy was estimated by using macroscopic mixture models. A measurement of the thermal properties of U-Zr-Ce was also performed to compare the evaluated results with the experimental data