Impact of Auto-irradiation on the Thermophysical Properties of Oxide Nuclear Reactor Fuels

The effect of a-damage on the thermophysical properties of UO2 was investigated using samples doped with 238Pu. Characterisations were performed after different storage periods, including X-ray diffraction to monitor the lattice parameter evolution, Knudsen-cell helium release experiments and transmission electron microscopy examinations. The apparent heat capacity was measured by differential scanning calorimetriy and the recovery stages observed were attributed to the recombination of a certain kind of point or extended defect. The thermal diffusivity, measured by the laser flash technique during annealing cycles, displayed similar recovery stages. The measurements show that the degradation of the diffusivity with increasing a-dose is not linear, and that saturation occurs at relatively low doses. A correlation quantifying this degradation is proposed. Comparison with the thermal diffusivity of very low burn-up rector irradiated samples, where the main source of degradation is radiation damage, shows that the annealing stages are similar.

STAICU Dragos;  WISS Thierry;  RONDINELLA Vincenzo;  HIERNAUT Jean-Pol;  KONINGS Rudy;  RONCHI C.; 

2010-11-15

ELSEVIER SCIENCE BV

JRC55903

0022-3115,   

www.elsevier.com/locate/jnucmat,    https://publications.jrc.ec.europa.eu/repository/handle/JRC55903,   

10.1016/j.jnucmat.2009.11.024,