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EFFECTS of RADIATION and LIGHT IONS BEHAVIOR in CERAMICS for FUSION BREEDER BLANKET

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EFFECTS of RADIATION and LIGHT IONS BEHAVIOR in CERAMICS for FUSION BREEDER BLANKET EFFECTS of RADIATION and LIGHT IONS BEHAVIOR in CERAMICS FOR FUSION BREEDER BLANKET AUTHOR: ELISABETTA CARELLA DIRECTED BY MARIA GONZÁLEZ M. TERESA HERNÁNDEZ A DISSERTATION FOR THE DEGREE OF DOCTOR OF PHILOSOPHY (MATERIALS PHYSICS) MADRID, 2014 FACULTAD DE CIENCIAS, DEPARTAMENTO DE FÍSICA DE MATERIALES GRUPO MIRE (MATERIALS OF INTEREST IN RENEWABLE ENERGY) UNIVERSIDAD AUTÓNOMA DE MADRID LABORATORIO NACIONAL DE FUSIÓN CENTRO DE INVESTIGACIÓN MEDIOAMBIENTALES, ENERGÉTICAS Y TECNOLÓGICAS EFFECT OF RADIATION AND LIGHT IONS BEHAVIOR IN CERAMICS FOR FUSION BREEDER BLANKET (EFECTOS DE LA RADIACIÓN Y COMPORTAMIENTO DE LOS IONES LIGEROS EN CERÁMICAS PARA LA ENVOLTURA REGENERADORA DE FUSIÓN) AUTORA: ELISABETTA CARELLA, LICENCIADA EN CIENCIAS FÍSICAS DIRECTORAS DE TESIS: MARÍA GONZÁLEZ, DOCTORA EN CIENCIAS QUÍMICAS M.TERESA HERNÁNDEZ, DOCTORA EN CIENCIAS QUÍMICAS TUTOR: JOSÉ FRANCISCO FERNÁNDEZ, DOCTOR EN CIENCIAS FÍSICAS 2014 Según la forma de andar de cada cual, se puede ver si ha encontrado su camino. El hombre que se acerca a su objetivo ya no camina, baila. Friedrich Nietzsche, Así habló Zaratustra The good life is one inspired by love and guided by knowledge. Bertrand Russell, Why I am not a Christian Science alone of all the subjects contains within itself the lesson of the danger of belief in the infallibility of the greatest teachers in the preceding generation ... Learn from science that you must doubt the experts. As a matter of fact, I can also define science another way: Science is the belief in the ignorance of experts. Richard Feynman, The Pleasure of Finding Things Out : The Best Short Works of Richard Feynman A GIUSI, LELLA Y NINO CON TODA MI GRATITUD Y AMOR POR SER TAN INCREÍBLE FAMILIA INDEX FIGURE INDEX I TABLE INDEX V LIST OF ABBREVIATIONS VII INTRODUCCIÓN 1 1. Objetivo 1 2. Estructura del trabajo 2 PART I: THEORY 5 CHAPTER 1 7 THERMONUCLEAR FUSION ENERGY 7 1. Motivation for FUSION research 8 1.1. Safety and environmental impact 10 1.2. Fusion as an energy source Fuels 11 1.3. Reactor designs 12 2. Achieving fusion energy: IFMIF facility, ITER and DEMO projects. 15 3. Fusion materials 17 3.1. Structural materials 19 3.2. Plasma facing materials 20 3.3. Functional materials 20 3.4. Breeding Blanket materials 20 4. Description of HCPB Blanket 24 CHAPTER 2 29 THE SOLID BREEDER BLANKET CONCEPT 29 1. The role of the solid Breeder Blanket in a fusion reactor 30 2. Main characteristics of lithium-based ceramics 33 3. Phase diagram and structure of the studied ceramics 35 3.1. Li2TiO3 35 3.2. Silica-based ceramics 37 CHAPTER 3 41 TRITIUM 41 1. Tritium inventory 42 Index 2. Tritium production 44 3. Tritium release 45 4. Modelling tritium behaviour 47 5. Indirect measurements of tritium diffusion and state of the art 49 CHAPTER 4 51 EFFECTS OF RADIATION IN CERAMICS FOR FUSION BREEDER BLANKET 51 1. Radiation effects in materials 52 2. Radiation defects in breeder blanket ceramics 54 2.1. Electronic Defects 56 2.2. Ionic defects 57 3. Basic effects of radiation in lithium-based ceramics: state of the art 58 4. Review of the radiation sources for defects production 59 3.1. High energy photons 59 3.2. Ions 60 PART II: EXPERIMENTS AND RESULTS 65 CHAPTER 5 67 FABRICATION and CHEMICAL CHARACTERIZATION of LITHIUM CERAMICS with DIFFERENT Li-CONTENT 67 5. State of the art 69 6. Important features for the optimization of BB ceramics 70 7. Powder characterization methods 71 3.1. Thermal analysis 71 3.2. X-Ray Diffraction 73 3.3. Infrared Spectroscopy (IR) 74 3.4. Secondary ion mass spectrometry 76 3.5. Density and porosimetry 77 3.6. Electron Microscopy 79 4. Synthesis processes of Li-Si powders 81 I. Solid-state method (SS) 81 II. Suspension dried in a Rotary Evaporator (RV) 82 III. Spray Drying Technique (SD) 83 5. Characterization of Li4SiO4 and Li8SiO6 ceramics 84 5.1. Differential thermal analysis + Thermo gravimetry 85 5.2. Study of crystalline phases: X-Ray Diffraction 87 5.3. Attenuated Total Reflectance - Infra Red Spectroscopy 90 5.4. Microstructure of powders by SEM 91 5.5. Primary conclusions 93 Index 6. Sintering of Li-ceramics: the effect of Li-content in dense bodies 93 a) X-Ray Diffraction 93 b) Secondary ion mass spectrometry 94 c) Density and pore distribution 95 d) Scanning Electron Microscopy 96 7. Discussion 97 8. Conclusions 99 CHAPTER 6 101 ELECTRICAL MEASUREMENTS AND γ - RADIATION EFFECT 101 1. The effect of radiation on electrical properties 102 2. Electronic structure of breeder blanket ceramics 103 3. Fundamentals of Impedance Spectroscopy 104 4. Experimental procedure 110 5. Li-content variation versus electrical conductivity 112 6. The electrical behaviour of Li-orthosilicate 117 6.1. Results 117 6.2. Discussion 123 7. The electrical behaviour of Li- metatitanate 124 7.1. Results 125 7.2. Discussion 127 8. Positron annihilation spectroscopy on gamma irradiated ceramics 128 9. Indirect measurements: T mobility and Li-burn up effect 131 10. Conclusions 133 CHAPTER 7 135 LIGHT IONS TRANSPORT 135 1. A big deal: understanding tritium behaviour 136 2. Light ion detection 137 2.1. Ion implantation 138 2.2. Ion Beam Analysis (IBA) 139 2.3. Nuclear Reaction Analysis 142 3. D-depth profiling experiments in as-implanted and annealed ceramic breeders 144 3.1. Experimental details 145 3.2. Results and discussion 149 3.2.1. Microstructural features 149 3.2.2. Deuterium analytical determination by NRA 152 Index 3.2.1.1. D-behaviour in damaged ceramics 159 3.2.2.2. Structural characterization after experiments 161 Helium-3 thermal behaviour experiments in Li2TiO3 ceramics 162 4.1. Experimental part: the DIADDHEM device 163 4.2. Results and discussion 168 4.2.1. Sample previous characterization 168 4.2.2. 3He analytical determination 172 4.2.3. 3He behavior in damaged ceramics 178 4.3. Microstructural and structural characterization after experiments 181 5. Comparison and discussion of light ions behaviour 184 6. Conclusions 188 CHAPTER 8 190 CONCLUSIONS 190 CONCLUSIONES 192 References 196 Publications and conference contributions 215 PUBLICATIONS 215 CONFERENCES CONTRIBUTIONS 217 F.I Figure Index FIGURE INDEX Figure 1.1: World energy consumption with estimated extrapolation. Figure 1.2: The data for three reactions are shown: D-D, D-T and D-3He. Figure 1.3: Modular coilset and outer magnetic flux surface for the W7-X stellarator. Figure 1.4: A schematic view of a tokamak. Figure 1.5: Schematic fusion power station. Figure 1.6: Fusion reactor scheme with the four main group’s classification. Figure 1.7: Schematic of tritium breeding blanket configuration. Figure 1.8: The TBM systems extend from Vacuum Vessel to Port Cell and buildings in ITER. Figure 1.9: HCPB test blanket module (TBM) using lithium ceramics as breeding material. Figure 1.10: Reference Scheme for Tritium Transport in HCPB Blanket. Figure 2.1: Schematic of tritium breeding blanket configuration Figure 2.2: Phase diagram of the Li2O–TiO2 system. Figure 2.3: Crystal structure of a unit cell of C2/c Li2TiO3 compound. Figure 2.4: The phase diagram of the Li2O-SiO2 system. Figure 2.5: Crystal structure of a unit cell of Cmc21 Li2SiO3. Figure 2.6: A model of the Li4SiO4 crystallographic structure. Figure 3.1: Schematic behaviour of tritium production and release from a pebble. Figure 3.2: Mechanism of tritium transport in ceramic breeder blanket. Figure 3.3: Schematization of the main steps to develop a tritium transport model. Figure 4.1: Microstructural evolution of the lattice after a point defect creation. Figure 4.2: Different types of radioactive decays. Figure 4.3: Interaction of ionizing radiation with matter. Figure 4.4: A process of gamma-rays emission from excited nuclei. Figure 4.5: Displacement-damage effectiveness for various energetic particles in Ni. Figure 5.1: Furnace components for thermal analysis. Figure 5.2: A wave diffraction from a set of planes. Figure 5.3: Schematic representation of multiple internal reflection effect in ATR. F.II Figure Index Figure 5.4: Principles of SIMS technique. Figure 5.5: Schematic representation of the different kind of pores. Figure 5.6: Scheme of the interactions among the electron beam and the matter. Figure 5.7: Flux diagram of solid state (SS) method. Figure 5.8: Flux diagram for rotary evaporator method. Figure 5.9: Flux diagram of spray drying (SD) technique. Figure 5.10: DTA and TG diagrams obtained in the final step of the synthesis processes. Figure 5.11: XRD patterns for the Li4SiO4 calcined powder. Figure 5.12: XRD patterns for the Li8SiO6 obtained with the three fabrication routes. Figure 5.13: IR spectra of the final phases found in the Li4SiO4and Li8SiO6 materials. Figure 5.14: SEM captures of the particles of Li4SiO4 material. Figure 5.15: SEM captures of the particles of Li8SiO6 material. Figure 5.16: Static SIMS spectra for the elemental analysis of the ceramics fabricated. Figure 5.17: SEM images of the polished surface. Figure 5.18: SEM image of the MTi pores. Figure 6.1: The application of a sinusoidal current, measuring the voltage response. Figure 6.2: Nyquist plot with impedance vectors indicating the main variables. Figure 6.3: Equivalent circuit with one capacitor and one resistor element. Figure 6.4: Simplified model of grain and grain-boundaries contributions in ionic conduction. Figure 6.5: Semicircles of the equivalent circuit schematically representing the brick layer model. Figure 6.6: Nayade installation pool. Figure 6.7: Experimental set-up for EIS measurements. Figure 6.8: Complex impedance plot of Li4 ceramic. Figure 6.9: EIS spectra for Li-based ceramics with different Li:Si proportion.
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