The two step oxidation of UO2+x and reduction of U3O8 powders observed during Differential Thermal Analysis (DTA) has been exploited to determine their Specific Surface Areas
(SSAs). The results obtained by this method have been compared with the Braunauer, Emmett and Teller (BET) method and are
found to be in good agreement in the SSA range of 2–4 m2/gm in the case of UO2+x obtained from ADU route and 4–8 m2/gm in the case of AUC route. A precision of ±0.1 m2/gm is obtained. The maximum temperature of oxidation and reduction of these oxides are dependent upon their preparative routes
such as Ammonium Diuranate (ADU) and Ammonium Uranyl Carbonate (AUC).