The Radiation Chemistry of Gases at the Interface with Ceramic Oxides A thesis submitted to the University of Manchester for the degree of Doctor of Philosophy in the Faculty of Engineering and Physical Sciences 2015 Luke Jones School of Chemistry Dalton Cumbrian Facility 1 7161060 List of Contents List of Contents ................................................................................................................ 1 List of Figures ................................................................................................................... 6 List of Tables .................................................................................................................. 14 Abbreviations and Acronyms .......................................................................................... 16 Abstract ......................................................................................................................... 17 Declaration .................................................................................................................... 18 Copyright Statement ...................................................................................................... 19 Acknowledgements ........................................................................................................ 20 The Author ..................................................................................................................... 22 Thesis Structure .............................................................................................................. 23 1 Introduction ............................................................................................................ 25 The Challenge .................................................................................................................................... 25 1.1 Background ........................................................................................................................... 26 1.2 Radiation Chemistry .............................................................................................................. 32 1.2.1 Sources of Radiation ..................................................................................................... 32 1.2.2 Radiation Interactions with Matter .............................................................................. 35 1.2.3 Radiolytic Track Formation ........................................................................................... 44 2 Literature Review .................................................................................................... 47 2.1 푃푢푂2 Storage Canisters ........................................................................................................ 47 2.2 Water Adsorption on 푃푢푂2 .................................................................................................. 50 2.3 Radiolysis of Adsorbed Water ............................................................................................... 51 2.4 Radiolysis of Gases in Contact with 푃푢푂2 ............................................................................. 52 2.5 Radiolysis of 퐻2 − 푂2 in Contact with Other Materials ........................................................ 55 2.6 Radiolysis of Hydrogen and Oxygen ...................................................................................... 56 2.7 Air Radiolysis ......................................................................................................................... 58 Aims and Objectives .......................................................................................................................... 60 1 7161060 3 Experimental ........................................................................................................... 61 3.1 Materials ............................................................................................................................... 61 3.1.1 Gases ............................................................................................................................. 61 3.1.2 Chemicals ...................................................................................................................... 61 3.2 Irradiation Sources ................................................................................................................ 62 3.2.1 Cobalt-60 Source ........................................................................................................... 62 3.2.2 Pelletron Ion Accelerator .............................................................................................. 64 3.3 Analytical Techniques ........................................................................................................... 65 3.3.1 Gas Chromatography (GC) ............................................................................................ 65 3.3.2 Ion Chromatography (IC) ............................................................................................... 66 3.3.3 Surface Area Measurements......................................................................................... 66 3.3.4 Thermogravimetric Analysis (TGA) ............................................................................... 67 3.3.5 Diffuse Reflectance Infra-red Spectroscopy (DRIFT) ..................................................... 67 3.3.6 UV-Vis Spectroscopy ..................................................................................................... 68 3.3.7 Scanning Electron Microscopy (SEM)............................................................................ 68 3.4 Experimental ......................................................................................................................... 69 3.4.1 Mixing of 퐻2 − 푂2 − 퐴푟 Samples ................................................................................. 69 3.4.2 Air Radiolysis ................................................................................................................. 71 3.4.3 Oxide Regeneration ...................................................................................................... 73 3.4.4 Accelerator Experiments ............................................................................................... 73 4 Development of γ-Irradiation Reaction Vessel .......................................................... 76 4.1 Initial Vessel Design .............................................................................................................. 76 4.1.1 GC Configuration and Calibration ................................................................................. 77 4.2 Reaction Vessel Mark II ......................................................................................................... 82 4.2.1 GC Calibration ............................................................................................................... 83 4.3 Reaction Vessel Mark III ........................................................................................................ 86 4.3.1 GC Configuration and Calibration ................................................................................. 86 4.4 Gas Mixing ............................................................................................................................. 92 2 7161060 5 Dosimetry ................................................................................................................ 97 5.1 Background ........................................................................................................................... 97 5.2 Aqueous Dosimetry ............................................................................................................... 99 5.3 Calculation of Absorbed Dose using 60퐶표 Source ............................................................... 103 5.3.1 Adsorbed Dose in Gaseous Systems ........................................................................... 105 5.3.2 Literature Review of Heterogeneous System Dosimetry ............................................ 107 5.4 Disadvantages of Fricke Dosimetry with Metal Vessels ..................................................... 109 5.5 Gas Phase Dosimetry .......................................................................................................... 110 5.5.1 Gas Phase Dosimetry Literature.................................................................................. 110 5.5.2 Ethylene Dosimetry Results ........................................................................................ 113 5.6 Ion Accelerator Dosimetry .................................................................................................. 114 6 Oxide Powder Characterisation .............................................................................. 118 6.1 Properties of 퐶푒푂2 .............................................................................................................. 118 6.1.1 As Received ................................................................................................................. 118 6.1.2 Regenerated 퐶푒푂2 Properties .................................................................................... 121 6.1.3 Comparison of ‘As Received’ and Regenerated 퐶푒푂2 ................................................ 125 6.2 Properties of 푍푟푂2 .............................................................................................................. 127 6.2.1 As Received ................................................................................................................