Thermal Expansion of Simulated Spent PWR Fuel and Simulated DUPIC Fuel

Abstract

Thermal expansions of simulated spent PWR fuel and simulated DUPIC fuel were studied using a dilatometer in the temperature range from 298 to 1900 K. The densities of simulated spent PWR fuel and simulated DUPIC fuel used in the measurement were 10.28 g⋅cm⁻³ (95.4% of TD) and 10.26 g⋅cm⁻³ (95.1% of TD), respectively. The linear thermal expansions of the simulated fuels are higher than that of UO₂, and the difference between these fuels and UO₂ increases progressively with temperature. However, the difference between simulated spent PWR fuel and simulated DUPIC fuel is extremely small, less than the experimental error. For the temperature range from 298 to 1900 K, simulated spent PWR fuel and simulated DUPIC fuel have the same average linear thermal expansion coefficient of 1.39×10⁻⁵K⁻¹. As the temperature increases to 1900 K, the relative densities of simulated spent PWR fuel and simulated DUPIC fuel decrease to 93.8% of initial densities at 298 K.