Uranyl peroxide materials and their role in radical formation

Uranium (U) separation from spent nuclear fuel is an area of current research interest as reprocessing and advanced fuel development are important for fully utilizing nuclear energy resources. Currently reprocessing requires dissolution of UO2 fuel pellets in nitric acid media which yields the U(VI)O22+ cation which can be separated via the PUREX process. However; radiolysis of aqueous solution can generate reactive oxygen species (ROS) such as •OH, O2•- , e– (aq) , •H, and H2O2 that cause extractant degradation and the high concentrations of HNO3 are severe explosion, corrosion, and fire hazards. An alternative to this process is a CARBonate EXtraction method, termed CARBEX that in several studies has show to both be capable of dissolving and extracting U from UO2 in an elevated pH (pH = 7-10). Problems may arise though from large amounts of H2O2 added to aid in dissolution that will also generate ROS through H2O2 decomposition. This thesis intends to further understand solution state speciation and ROS interactions with UO22+ at similar pH conditions.