Formation of the rim structure in high burnup fuel
The process of grain subdivision or polygonization in UO(2) was studied by using ion irradiation techniques and by investigating the rim structure in high burnup UO(2) fuel. Ion irradiation with fission product ions caused first the formation of subgrain boundaries, observed in high resolution transmission electron microscopy (HRTEM). At higher doses, polygonization was completed at a well defined threshold. High burnup UO(2) fuel showing well developed rim zones was investigated in optical, scanning and transmission electron microscopy. The oxygen potential, the hardness and the fracture toughness of the restructured material and the radial dependence of porosity, grain subdivision, hardness and fracture toughness were measured. The fracture toughness was found to change at smaller radial positions than the other properties, indicating a nucleation process not affecting all properties to the same extent. The emerging picture for the formation of the rim structure in UO(2) is discussed.
Bibliographic Reference: Article: Journal of Nuclear Materials, Vol. 248 (1997) pp. 170-179
Record Number: 199810124 / Last updated on: 1998-02-12
Original language: en
Available languages: en