Thermal expansion of near stoichiometric (U,Er)O2 solid solutions

Thermal expansions of (U,Er)O2 solid solutions were investigated between room temperature and 1673 K by using a thermo-mechanical analyzer. Lattice parameters of the (U,Er)O2 pellets are lower than that of UO2 and they decrease as the Er contents increase. The linear thermal expansion and average thermal expansion coefficients of (U,Er)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 (U0.8Er0.2)O2 are 10.94 × 10− 6 and 11.42 × 10− 6 K− 1, respectively.