Crystallographic and Oxidation Kinetic Study of Uranium Dioxide by High Temperature X-Ray Diffractometry

摘要

The structural transformation of UO sub 2 sintered plates is studied as a function of temperature using X-ray diffractometry. The thermal expansion coefficient of UO sub(2.05) is determined and the structural transformation during isothermal oxidation is observed. The results favored a oxidation mechanism in which the rate-controling process is the diffusion of oxygen through the product layer of the new phase. Activation energies for the oxidation of UO sub 2 to UO sub(2.25) are found for different crystallographic planes (h,k,l). From this one can conclude that there is a preferential occupation of interstitial oxygen atoms within the UO sub 2 structure. (Atomindex citation 14:770870)