Variation of the lattice parameter and thermal expansion coefficient of (U,Dy)O2 as a function of DyO1.5 content

Thermal expansions of (U,Dy)O2 solid solutions were investigated between room temperature and 1673 K by using a thermo-mechanical analyzer. The lattice parameter of (U,Dy)O2 pellets is lower than that of UO2 and it decreases as Dy content increases. The linear thermal expansion and average thermal expansion coefficients of (U,Dy)O2 are higher than that of UO2. For the temperature range from room temperature to 1673 K, the average thermal expansion coefficient values for UO2 and (U0.8Dy0.2)O2 are 10.97 × 10−6 and 11.37 × 10−6 K−1, respectively.