Questions about UO2
(i) Write a defect reaction describing the formation of Schottky defects in UO2.
(ii) Write a defect reaction describing the formation of anti-Frenkel defects in UO2.
(iii) For UO2, the Schottky defect formation energy is 6.4 eV and the anti-Frenkel defect formation energy is 3.0 eV. Calculate concentration of each defect at 1600 °C. Also, assuming that you do not know both energy values, explain how you would experimentally go and determine which disorder dominates in UO2 at 1600 °C.
(iv) UO2 can exist as a single-phase material at a relatively wide range of compositions between UO1.61 and UO2.25. Considering your answer in (iii), write one defect reaction to describe the reduction of UO2 to an oxygen deficient composition