THE DEVELOPMENT OF 1,10-PHENANTHROLINE- DERIVED EXTRACTANTS FOR ADVANCED FUTURE NUCLEAR FUEL CYCLES A thesis submitted to The University of Manchester for the degree of Doctor of Philosophy in the Faculty of Science and Engineering Alyn C. Edwards School of Chemistry The University of Manchester 2017 TABLE OF CONTENTS ABSTRACT .................................................................................................................... 5 DECLARATION ............................................................................................................. 6 COPYRIGHT .................................................................................................................. 7 ACKNOWLEDGEMENTS ................................................................................................ 8 NUMBERING AND NOMENCLATURE ............................................................................ 9 ABBREVIATIONS ......................................................................................................... 10 AIMS ........................................................................................................................... 12 EXECUTIVE SUMMARY .............................................................................................. 13 CHAPTER ONE INTRODUCTION ................................................................................. 15 1.1. Nuclear Energy Production ............................................................................ 16 1.1.1. The Global Nuclear Energy Situation ........................................................ 16 1.1.2. The Nuclear Fuel Cycle (NFC) .................................................................. 17 1.1.3. Spent Nuclear Fuel ..................................................................................... 22 1.1.4. Nuclear Recycle ......................................................................................... 23 1.2. Aqueous Processes for Nuclear Recycle ........................................................ 25 1.2.1. An Introduction to Solvent Extraction ....................................................... 25 1.2.1.1. The Theory of Solvent Extraction .......................................................... 25 1.2.2. Actinide Separation Processes – An Overview .......................................... 27 1.2.3. Processes for the Co-Extraction of Uranium and Plutonium ..................... 28 1.2.3.1. PUREX Process ..................................................................................... 28 1.2.4. Processes for the Separation of Neptunium ............................................... 30 1.2.4.1. Advanced PUREX Process .................................................................... 30 1.2.5. Processes for the Co-Extraction of the Actinides and Lanthanides ........... 31 1.2.5.1. TRUEX Process ..................................................................................... 31 1.2.5.2. DIAMEX Process .................................................................................. 31 1.2.6. Processes for the Separation of the Actinides and Lanthanides ................. 33 1.2.6.1. SANEX Process ..................................................................................... 33 1.2.6.2. 1c-SANEX Process ................................................................................ 34 1.2.6.3. i-SANEX Process ................................................................................... 36 1.2.7. Processes for the Separation of Americium and Curium ........................... 37 1.2.7.1. AmSel ..................................................................................................... 37 1.2.8. Partitioning Processes Overview................................................................ 39 1.3. The Development of Actinide Selective Ligand Systems.............................. 40 2 1.3.1. Ligand Design Criteria ............................................................................... 41 1.3.2. 2,6-bis(1,2,4-triazin-3-yl)pyridine (BTP) Ligands..................................... 42 1.3.2.1. Synthesis ................................................................................................ 42 1.3.2.2. Hydrolytic and Radiolytic Stability ....................................................... 43 1.3.2.3. Separation Capabilities........................................................................... 45 1.3.2.4. Solid Phase Speciation ........................................................................... 46 1.3.2.5. Solution Phase Speciation ...................................................................... 47 1.3.2.6. Hydrophilic Analogues .......................................................................... 50 1.3.2.7. 2,6-di(1H-1,2,3-triazol-4-yl)pyridine (PyTri) Ligands .......................... 50 1.3.2.7.1. Synthesis ................................................................................................ 51 1.3.2.7.2. Hydrolytic and Radiolytic Stability ....................................................... 51 1.3.2.7.3. Separation Capabilities........................................................................... 52 1.3.2.7.4. Solution Phase Speciation ...................................................................... 52 1.3.3. 6,6’-bis(1,2,4-triazin-3-yl)-2,2’-bipyrdine (BTBP) Ligands...................... 53 1.3.3.1. Synthesis ................................................................................................ 53 1.3.3.2. Hydrolytic and Radiolytic Stability ....................................................... 54 1.3.3.3. Separation Capabilities........................................................................... 56 1.3.3.4. Solid Phase Speciation ........................................................................... 59 1.3.3.5. Solution Phase Speciation ...................................................................... 60 1.3.3.6. Hydrophilic Analogues .......................................................................... 62 1.3.4. 2,9-di(1,2,4-triazin-3-yl)-1,10-phenanthroline (BTPhen) Ligands ............ 64 1.3.4.1. Synthesis ................................................................................................ 64 1.3.4.2. Hydrolytic and Radiolytic Stability ....................................................... 65 1.3.4.3. Separation Capabilities........................................................................... 66 1.3.4.4. Solid Phase Speciation ........................................................................... 68 1.3.4.5. Solution Phase Speciation ...................................................................... 69 1.3.4.6. Hydrophilic Analogue ............................................................................ 70 1.4. Concluding Remarks .............................................................................. 70 CHAPTER TWO ........................................................................................................... 72 2.1. Abstract .......................................................................................................... 75 2.2. Introduction .................................................................................................... 75 2.3. Results ............................................................................................................ 78 2.3.1. Synthesis .................................................................................................... 78 2.3.2. X-Ray Crystallography .............................................................................. 81 2.3.3. pKa Measurements ..................................................................................... 82 3 2.3.4. Solvent Extraction Studies ......................................................................... 84 2.3.4.1. Kinetic Studies ....................................................................................... 84 2.3.4.2. Acid Dependence Studies ...................................................................... 86 2.3.4.3. TRLFS Studies ....................................................................................... 88 2.3.4.4. Computational Studies of Free Ligands ................................................. 90 2.4. Discussion ...................................................................................................... 93 2.5. Conclusions .................................................................................................... 94 2.6. Supporting Information for Chapter Two ...................................................... 96 CHAPTER THREE ..................................................................................................... 126 3.1. Abstract ........................................................................................................ 128 3.2. Introduction .................................................................................................. 128 3.3. Results .......................................................................................................... 130 3.3.1. Synthesis .................................................................................................. 130 3.3.2. X-ray Crystallography .............................................................................. 134 3.3.3. Solvent Extraction Studies ....................................................................... 135 3.4. Conclusions .................................................................................................