Radiation enhanced diffusion of Nd in UO2

Abstract

Single crystal UO 2 thin films with Nd as tracer elements in the film mid-plane have been grown on yttria-stabilized zirconia (YSZ) substrates. The films were irradiated with 1.8 MeV Kr + ions in the temperature range from 400 • C to 1113 • C, where an evident enhanced diffusion was found in UO 2. The temperature dependent measurements have shown an activation energy of 0.56 ± 0.04 eV below 800 • C, and 1.9 ± 0.3 eV above 900 • C. The rate-dependent measurements have shown a linear dependence on the radiation flux, which indicates radiation enhanced diffusion (RED) is in the sink limited kinetics regime. Comparison of the RED results between UO 2 and CeO 2 has shown significant differences, which indicates that CeO 2 used as UO 2 surrogate may be questioned in terms of cation diffusion.