We aim at characterising the local order associated to oxygen incorporation in UO2+x with 0 < x < 0.25 at different temperatures in order to better describe UO2 behaviour under irradation. The UO2+x diffraction patterns will be measured experimentally on several samples with different x at several temperatures in order to explore the UO phase diagram. The corresponding PDFs will be compared to UO2 and U4O9 reference PDFs obtained at the same temperature. Either the sample is a mixture of this two phases(as expected at low temperature) or new local defects are to be tested using pdfgui software.