Abstract: Five physical properties correlations are developed as functions of temperatureand local composition for FBR fuel--U--Pu--Zr alloy. The properties of interestinclude RT theoretical density, solidus (liquidus) temperature, thermal expansion,specific heat capacity and thermal conductivity. The uncertainties in models areestimated to be 0.5%, 5.7%, 5.5%, 5.0% and 9.7% respectively for the 95%confidence limit. These models are also suitable to U--Zr alloy also.