An Introduction to Nuclear Materials: Fundamentals and Applications

Covering both fundamental and advanced aspects in an accessible way, this textbook begins with an overview of nuclear reactor systems, helping readers to familiarize themselves with the varied designs. Then the readers are introduced to different possibilities for materials applications in the various sections of nuclear energy systems. Materials selection and life prediction methodologies for nuclear reactors are also presented in relation to creep, corrosion and other degradation mechanisms. An appendix compiles useful property data relevant for nuclear reactor applications. Throughout the book, there is a thorough coverage of various materials science principles, such as physical and mechanical metallurgy, defects and diffusion and radiation effects on materials, with serious efforts made to establish structure-property correlations wherever possible. With its emphasis on the latest developments and outstanding problems in the field, this is both a valuable introduction and a ready reference for beginners and experienced practitioners alike.

Table of Contents:
Preface XV 1 Overview of Nuclear Reactor Systems and Fundamentals 1 1.1 Introduction 1 1.2 Types of Nuclear Energy 2 1.2.1 Nuclear Fission Energy 2 1.2.2 Nuclear Fusion Energy 2 1.2.3 Radioisotopic Energy 3 1.3 Neutron Classification 3 1.4 Neutron Sources 3 1.5 Interactions of Neutrons with Matter 3 1.5.1 Fission Chain Reaction 5 1.6 Definition of Neutron Flux and Fluence 6 1.7 Neutron Cross Section 7 1.7.1 Reactor Flux Spectrum 10 1.8 Types of Reactors 11 1.8.1 A Simple Reactor Design 11 1.8.2 Examples of Nuclear Reactors 12 1.8.2.1 Generation-I Reactors 13 1.8.2.2 Generation-II Reactors 15 1.8.2.3 Generation-III and IIIþ Reactors 22 1.8.2.4 Generation-IV Reactors 25 1.9 Materials Selection Criteria 28 1.9.1 General Considerations 31 1.9.1.1 General Mechanical Properties 31 1.9.1.2 Fabricability 32 1.9.1.3 Dimensional Stability 32 1.9.1.4 Corrosion Resistance 32 1.9.1.5 Design 32 1.9.1.6 Heat Transfer Properties 32 1.9.1.7 Availability and Cost 33 1.9.2 Special Considerations 33 1.9.2.1 Neutronic Properties 33 1.9.2.2 Susceptibility to Induced Radioactivity 33 1.9.2.3 Radiation Stability 35 1.9.3 Application of Materials Selection Criteria to Reactor Components 35 1.9.3.1 Structural/Fuel Cladding Materials 36 1.9.3.2 Moderators and Reflectors 36 1.9.3.3 Control Materials 36 1.9.3.4 Coolants 36 1.9.3.5 Shielding Materials 37 1.10 Summary 37 Appendix 1.A 37 Additional Reading Materials 40 2 Fundamental Nature of Materials 43 2.1 Crystal Structure 43 2.1.1 Unit Cell 45 2.1.2 Crystal Structures in Metals 47 2.1.2.1 Body-Centered Cubic (BCC) Crystal Structure 47 2.1.2.2 Face-Centered Cubic (FCC) Crystal Structure 49 2.1.2.3 Hexagonal Close-Packed (HCP) Crystal Structure 49 2.1.3 Close Packing Geometry 52 2.1.4 Polymorphism 53 2.1.5 Miller Indices for Denoting Crystallographic Planes and Directions 54 2.1.5.1 Miller–Bravais Indices for Hexagonal Close-Packed Crystals 57 2.1.6 Interstitial Sites in Common Crystal Structures 59 2.1.7 Crystal Structure of Carbon: Diamond and Graphite 60 2.1.8 Crystal Structure in Ceramics 62 2.1.8.1 Rock Salt Structure 63 2.1.8.2 CsCl Structure 64 2.1.8.3 Fluorite Structure 65 2.1.8.4 Zincblende Structure 66 2.1.8.5 Corundum Structure 66 2.1.9 Summary 69 2.2 Crystal Defects 69 2.2.1 Point Defects 70 2.2.1.1 Point Defects in Metals/Alloys 70 2.2.1.2 Point Defects in Ionic Crystals 77 2.2.2 Line Defects 79 2.2.3 Surface Defects 84 2.2.3.1 Grain Boundaries 84 2.2.3.2 Twin Boundaries 86 2.2.3.3 Stacking Faults 87 2.2.3.4 Other Boundaries 88 2.2.4 Volume Defects 88 2.2.5 Summary 88 2.3 Diffusion 89 2.3.1 Phenomenological Theories of Diffusion 90 2.3.1.1 Fick’s First Law 90 2.3.1.2 Fick’s Second Law 91 2.3.2 Atomic Theories of Diffusion 95 2.3.3 Atomic Diffusion Mechanisms 97 2.3.4 Diffusion as a Thermally Activated Process 101 2.3.5 Diffusion in Multicomponent Systems 105 2.3.6 Diffusion in Different Microstructural Paths 106 2.3.6.1 Grain Boundary Diffusion 106 2.3.6.2 Dislocation Core Diffusion 108 2.3.6.3 Surface Diffusion 108 2.3.7 Summary 108 Bibliography 110 3 Fundamentals of Radiation Damage 111 3.1 Displacement Threshold 114 3.2 Radiation Damage Models 118 3.3 Summary 125 Bibliography and Suggestions for Further Reading 126 Additional Reading 126 4 Dislocation Theory 127 4.1 Deformation by Slip in Single Crystals 127 4.1.1 Critical Resolved Shear Stress 130 4.1.2 Peierls–Nabarro (P–N) Stress 133 4.1.3 Slip in Crystals: Accumulation of Plastic Strain 134 4.1.4 Determination of Burgers Vector Magnitude 136 4.1.5 Dislocation Velocity 137 4.2 Other Dislocation Characteristics 140 4.2.1 Types of Dislocation Loops 140 4.2.1.1 Glide Loop 141 4.2.1.2 Prismatic Loop 141 4.2.2 Stress Field of Dislocations 142 4.2.2.1 Screw Dislocation 142 4.2.2.2 Edge Dislocation 143 4.2.3 Strain Energy of a Dislocation 144 4.2.3.1 Frank’s Rule 145 4.2.4 Force on a Dislocation 147 4.2.5 Forces between Dislocations 151 4.2.6 Intersection of Dislocations 154 4.2.7 Origin and Multiplication of Dislocations 157 4.2.7.1 Consequences of Dislocation Pileups 158 4.3 Dislocations in Different Crystal Structures 160 4.3.1 Dislocation Reactions in FCC Lattices 160 4.3.1.1 Shockley Partials 160 4.3.1.2 Frank Partials 162 4.3.1.3 Lomer–Cottrell Barriers 163 4.3.2 Dislocation Reactions in BCC Lattices 165 4.3.3 Dislocation Reactions in HCP Lattices 166 4.3.4 Dislocation Reactions in Ionic Crystals 166 4.4 Strengthening (Hardening) Mechanisms 167 4.4.1 Strain Hardening 168 4.4.2 Grain Size Strengthening 170 4.4.3 Solid Solution Strengthening 172 4.4.3.1 Elastic Interaction 173 4.4.3.2 Modulus Interaction 173 4.4.3.3 Long-Range Order Interaction 173 4.4.3.4 Stacking Fault Interactions 173 4.4.3.5 Electrical Interactions 173 4.4.4 Strengthening from Fine Particles 174 4.4.4.1 Precipitation Strengthening 175 4.4.4.2 Dispersion Strengthening 177 4.5 Summary 178 Bibliography 180 Additional Reading 180 5 Properties of Materials 181 5.1 Mechanical Properties 181 5.1.1 Tensile Properties 184 5.1.1.1 Stress–Strain Curves 184 5.1.1.2 Effect of Strain Rate on Tensile Properties 192 5.1.1.3 Effect of Temperature on Tensile Properties 193 5.1.1.4 Anisotropy in Tensile Properties 195 5.1.2 Hardness Properties 196 5.1.2.1 Macrohardness Testing 197 5.1.2.2 Microhardness Testing 198 5.1.3 Fracture 200 5.1.3.1 Theoretical Cohesive Strength 201 5.1.3.2 Metallographic Aspects of Fracture 202 5.1.4 Impact Properties 203 5.1.4.1 Ductile–Brittle Transition Behavior 206 5.1.5 Fracture Toughness 207 5.1.5.1 Test Procedure 209 5.1.6 Creep Properties 211 5.1.6.1 Creep Constitutive Equation 212 5.1.6.2 Creep Curve 215 5.1.6.3 Stress and Creep Rupture 216 5.1.6.4 Creep Mechanisms 219 5.1.7 Fatigue Properties 227 5.1.7.1 Fatigue Curve 229 5.1.7.2 Miners Rule 234 5.1.7.3 Crack Growth 234 5.1.7.4 Paris Law 235 5.1.7.5 Factors Affecting Fatigue Life 238 5.1.7.6 Protection Methods against Fatigue 238 5.1.8 Creep–Fatigue Interaction 239 5.2 Thermophysical Properties 240 5.2.1 Specific Heat 240 5.2.2 Thermal Expansion 244 5.2.3 Thermal Conductivity 246 5.2.4 Summary 249 5.3 Corrosion 249 5.3.1 Corrosion Basics 249 5.3.2 Types of Corrosion Couples 253 5.3.2.1 Composition Cells 253 5.3.2.2 Concentration Cells 253 5.3.2.3 Stress Cells 254 5.3.3 Summary 259 Appendix 5.A 260 Appendix 5.B 260 Bibliography and Suggestions for Further Reading 265 Additional Reading 266 6 Radiation Effects on Materials 267 6.1 Microstructural Changes 267 6.1.1 Cluster Formation 271 6.1.2 Extended Defects 274 6.1.2.1 Nucleation and Growth of Dislocation Loops 275 6.1.2.2 Void/Bubble Formation and Consequent Effects 275 6.1.3 Radiation-Induced Segregation 286 6.1.4 Radiation-Induced Precipitation or Dissolution 287 6.2 Mechanical Properties 287 6.2.1 Radiation Hardening 287 6.2.1.1 Saturation Radiation Hardening 292 6.2.1.2 Radiation Anneal Hardening (RAH) 293 6.2.1.3 Channeling: Plastic Instability 294 6.2.2 Radiation Embrittlement 295 6.2.2.1 Effect of Composition and Fluence 297 6.2.2.2 Effect of Irradiation Temperature 297 6.2.2.3 Effect of Thermal Annealing 299 6.2.3 Helium Embrittlement 300 6.2.4 Irradiation Creep 302 6.2.5 Radiation Effect on Fatigue Properties 305 6.3 Radiation Effects on Physical Properties 306 6.3.1 Density 307 6.3.2 Elastic Constants 307 6.3.3 Thermal Conductivity 307 6.3.4 Thermal Expansion Coefficient 308 6.4 Radiation Effects on Corrosion Properties 308 6.4.1 Metal/Alloy 308 6.4.2 Protective Layer 308 6.4.3 Corrodent 309 6.4.3.1 LWR Environment 309 6.4.3.2 Liquid Metal Embrittlement 313 6.4.4 Irradiation-Assisted Stress Corrosion Cracking (IASCC) 313 6.5 Summary 314 Bibliography 316 7 Nuclear Fuels 319 7.1 Introduction 319 7.2 Metallic Fuels 321 7.2.1 Metallic Uranium 321 7.2.1.1 Extraction of Uranium 322 7.2.1.2 Nuclear Properties 323 7.2.1.3 Uranium Crystal Structure and Physical Properties 324 7.2.1.4 Mechanical Properties 326 7.2.1.5 Corrosion Properties 327 7.2.1.6 Alloying of Uranium 328 7.2.1.7 Fabrication of Uranium 330 7.2.1.8 Thermal Cycling Growth in Uranium 330 7.2.1.9 Irradiation Properties of Metallic Uranium 331 7.2.2 Metallic Plutonium 335 7.2.2.1 Crystal Structure and Physical Properties of Plutonium 336 7.2.2.2 Fabrication of Plutonium 338 7.2.2.3 Mechanical Properties of Plutonium 338 7.2.2.4 Corrosion Properties 339 7.2.2.5 Alloying of Plutonium 341 7.2.3 Metallic Thorium Fuel 341 7.2.3.1 Extraction of Thorium and Fabrication 342 7.2.3.2 Crystal Structure and Physical Properties of Metallic Thorium 343 7.2.3.3 Mechanical Properties 343 7.2.3.4 Corrosion Properties of Thorium 344 7.2.3.5 Alloying of Thorium 345 7.2.3.6 Radiation Effects 346 7.2.3.7 Pros and Cons of Thorium-Based Fuel Cycles 346 7.3 Ceramic Fuels 347 7.3.1 Ceramic Uranium Fuels 347 7.3.1.1 Uranium Dioxide (Urania) 347 7.3.2 Uranium Carbide 352 7.3.3 Uranium Nitride 353 7.3.4 Plutonium-Bearing Ceramic Fuels 354 7.3.5 Thorium-Bearing Ceramic Fuels 354 7.4 Summary 356 Bibliography 357 Additional Reading 358 Appendix A Stress and Strain Tensors 359 Appendix B 367 Index 375