Thermodynamic and kinetic modelling of fuel oxidation behaviour in operating defective fuel

Kinetics of precipitation of U4O9 from hyperstoichiometric UO2+x

“…Many investigators have studied the U-O system, most recently summarized by Guéneau et al [2], Chevalier et al [3] and Lewis et al [4] as 0022-3115/$ -see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jnucmat.2007.03.054 UO 2 has traditionally been a popular fuel for both military and commercial water-cooled power reactors.…”

Simulations of heat and oxygen diffusion in UO2 nuclear fuel rods

“…This effect can be significant, for example the dependence of thermal conductivity and other thermodynamic properties on non-stoichiometry for mixed oxide fuels and urania can be quite strong [7,8]. Recent simulations of heat transport coupled with oxygen diffusion in CANDU fuel elements [9,10] show that the radial changes in temperature and stoichiometry are strongly coupled. Furthermore, other studies [11] show that in hyper-stoichiometric urania, the heat of transport of oxygen is negative and these ions tend to accumulate in the regions of high temperature due to the so-called thermal diffusion, or Soret effect (the transport of oxygen atoms due to a temperature gradient).…”

Anomalies in nonstoichiometric uranium dioxide induced by a pseudo phase transition of point defects

“…Experiments indicated that the stable range of x at low temperature is very narrow, especially in the x < 0 side. [13,14] Nevertheless, a meta-stable UO 2+x with x = −0.02 had been successfully synthesized at room temperature in laboratory. [15] Although above discussions showed that the anomalies for this chemical composition is weak in the specific volume or shock temperature, a kink in the C P curve is still evident, which implies that the pseudo-phase transition can be detected by a highly accurate measurement of C P in UO 1.98 .…”