Reprocessing in the nuclear fuel cycle is becoming essential considering the increasing demands for energy world-wide and the role nuclear energy will have in the future. Reprocessing not only aids in prolonging the supply of fissionable isotopes, but also strives to reduce the volume and mass of radioactive waste. However, there are various issues that must be addressed to make reprocessing viable. These issues are nuclear forensics/safeguards, optimization of reprocessing fuel cycles, and economic incentive to reprocess. This thesis aims to address these issues in the broader scope. Chapter 1 evaluated a phosphine oxide ligand for use as a safeguards signature in UREX or UREX variant. This chapter took advantage of the fluorescence properties of polyaromatic hydrocarbons as an in-situ marker. Chapter 2 investigated spectroscopic phenomenon that water creates with lanthanides bound to acidic organophosphorus ligands. The lanthanide coordination chemistry was probed using XAFS, fluorescence spectroscopy, DFT and UVVis spectroscopy. The results showed that for larger lanthanides water could coordinate inner sphere and change the absorption spectroscopy. Chapter 3 and 4 looked at the molybdenum chemistry with acidic organophosphorus ligands. Chapter 3 focused on the process efficiency of extracting and stripping molybdenum, while chapter 4 focused on the coordination chemistry of the process. Finally, appendix A did not focus on the chemistry side of reprocessing, but instead looked at the economic incentives of reprocessing if both actinides and non-radioactive fission products were separated and sold.
Coordination Chemistry of Lanthanide Elements. II. Cationic Lanthanide Complexes of Trimorpholino Phosphine Oxide
