Waste Immobilization in Glass and Ceramic Based Hosts: Radioactive, Toxic and Hazardous Wastes

Preface page xi

Acknowledgements xiii

List of Abbreviations xv

1. Introduction 1

1.1 Categories of Waste and Waste Generation in the Modern World 1

1.1.1 Radioactive Wastes from Nuclear Power and Defence Operations 2

1.1.2 Toxic and Hazardous Wastes 7

1.1.3 Other Sources of Waste Material 9

1.2 General Disposal Options 11

1.3 Radiation Issues 19

1.4 Waste Disposal and the Oklo Natural Nuclear Reactors 21

1.5 Nuclear Accidents and the Lessons Learnt 25

References 31

2. Materials Toxicity and Biological Effects 37

2.1 Metals 38

2.1.1 Beryllium, Barium and Radium 38

2.1.2 Vanadium 39

2.1.3 Chromium, Molybdenum and Tungsten 40

2.1.4 Manganese, Technetium and Rhenium 40

2.1.5 Platinum-Group Metals 41

2.1.6 Nickel 42

2.1.7 Copper, Silver and Gold 42

2.1.8 Zinc, Cadmium and Mercury 43

2.1.9 Aluminium and Thallium 45

2.1.10 Tin and Lead 46

2.1.11 Arsenic, Antimony and Bismuth 48

2.1.12 Selenium, Tellurium and Polonium 49

2.1.13 Thorium, Uranium, Neptunium, Plutonium and Americium 50

2.2 Compounds 51

2.3 Asbestos 51

References 55

3. Glass and Ceramic Based Systems and General Processing Methods 57

3.1 Glass Formation 58

3.1.1 Glass-Forming Ability 58

3.1.2 Thermal Stability 61

3.2 Types of Glass 61

3.2.1 Silicate and Borosilicate Glasses 61

3.2.2 Phosphate Glasses 61

3.2.3 Rare Earth Oxide Glasses 62

3.2.4 Alternative Glasses 62

3.3 Ceramics 62

3.4 Glass-Ceramics 63

3.5 Glass and Ceramic Based Composite Systems 68

3.6 Processing of Glass and Ceramic Materials 68

3.6.1 Melting and Vitrifi cation 69

3.6.2 Powder Processing and Sintering 69

3.6.3 Hot Pressing 69

3.6.4 Sol-Gel Processing 70

3.6.5 Self-Propagating High Temperature Synthesis 70

3.6.6 Microwave Processing 70

References 71

4. Materials Characterization 75

4.1 Chemical Analysis 75

4.2 Thermal Analysis 76

4.3 Structural Analysis 78

4.3.1 Optical and Electron Microscopy 78

4.3.2 Energy Dispersive Spectroscopy 79

4.3.3 X-ray and Neutron Diffraction 79

4.3.4 Infra-Red and Raman Spectroscopy 80

4.3.5 Mössbauer Spectroscopy 80

4.3.6 Nuclear Magnetic Resonance 80

4.4 Mechanical Properties 81

4.4.1 Fracture Mechanics 81

4.4.2 Flexural Strength of Materials 83

4.4.3 Lifetime Behaviour 83

4.5 Chemical Durability and Standardized Tests 87

4.6 Radiation Stability 92

4.7 Other Properties Relevant to Wasteforms 94

4.8 Use of Nonradioactive Surrogates 94

References 96

5. Radioactive Wastes 101

5.1 Sources and Waste Stream Compositions 101

5.1.1 Nuclear Reactor Spent Fuel Wastes 102

5.1.2 Defence Wastes 107

5.1.3 Surplus Materials 108

5.1.4 Special or Unusual Categories of Radioactive Waste 109

5.2 General Immobilization Options 111

References 115

6. Immobilization by Vitrification 121

6.1 Vitrification History and the Advancement of Melter Design 121

6.1.1 Pot Processes 122

6.1.2 Continuous Melting by Induction Furnace 124

6.1.3 Joule-Heated Ceramic Melters 128

6.1.4 Cold Crucible Induction Melters 131

6.1.5 Plasma Arc/Torch Melters 135

6.1.6 Microwave Processing 138

6.1.7 In situ Melting 138

6.1.8 Bulk Vitrification 138

6.1.9 Alternative Melting Techniques 138

6.1.10 Vitrification Incidents and the Lessons that have been Learnt 140

6.2 Difficult Waste Constituents 144

6.2.1 Molybdenum and Caesium 144

6.2.2 Platinum Group Metals 147

6.2.3 Technetium 149

6.2.4 Chromium, Nickel and Iron 150

6.2.5 Halides 150

6.2.6 Sulphates 150

6.2.7 Phosphates 151

6.3 Effect of Specific Batch Additives on Melting Performance 151

6.4 Types of Glass and Candidate Glass Requirements 151

6.4.1 Silicate and Borosilicate Glass 151

6.4.2 Phosphate Glasses 163

6.4.3 Rare Earth Oxide Glasses 165

6.4.4 Alternative Glasses 166

6.5 Glass-Forming Ability 168

6.6 Alternative Methods for Producing Glassy Wasteforms 169

6.6.1 Sintered and Porous Glass 169

6.6.2 Hot-Pressed Glass 171

6.6.3 Microwave Sintering 175

6.6.4 Self-Sustaining Vitrification 176

6.6.5 Plasma Torch Incineration and Vitrification 177

References 177

7. Immobilization of Radioactive Materials as a Ceramic Wasteform 185

7.1 Titanate and Zirconate Ceramics 185

7.2 Phosphate Ceramics 203

7.3 Aluminosilicate Ceramics 207

7.4 Alternative Ceramics 209

7.5 Cement Based Systems 211

References 212

8. Immobilization of Radioactive Materials as a Glass-Ceramic Wasteform 221

8.1 Barium Aluminosilicate Glass-Ceramics 222

8.2 Barium Titanium Silicate Glass-Ceramics 222

8.3 Calcium Magnesium Silicate Glass-Ceramics 222

8.4 Calcium Titanium Silicate Glass-Ceramics 227

8.5 Basaltic Glass-Ceramics 228

8.6 Zirconolite Based Glass-Ceramics 230

8.7 Alternative Silicate Based Glass-Ceramics 234

8.8 Phosphate Based Glass-Ceramics 234

References 237

9. Novel Hosts for the Immobilization of Special or Unusual Categories of Radioactive Wastes 241

9.1 Silicate Glasses 241

9.2 Phosphate Glasses 246

9.3 Alternative Vitrification Routes 249

9.4 Ceramic-Based Hosts 251

9.5 Glass-Encapsulated Composite and Hybrid Systems 253

9.6 Oxynitride Glasses 259

9.7 Plutonium Disposition 260

References 266

10. Properties of Radioactive Wasteforms 275

10.1 Thermal Stability 275

10.2 Chemical Durability 276

10.2.1 General Principles of Glass Durability 277

10.2.2 Durability of Silicate Based Glasses in Water 282

10.2.3 Durability of Silicate Based Glasses in Groundwaters and Repository Environments 291

10.2.4 Durability of Phosphate Based Glasses 296

10.2.5 Lessons to be Learnt from Archaeological Glasses 297

10.2.6 Ceramic Durability 301

10.2.7 Glass-Ceramic Durability 308

10.2.8 Durability of Glass-Encapsulated Ceramic Hybrid Wasteforms 309

10.2.9 Influence of Colloids 310

10.3 Radiation Stability 311

10.3.1 Glass Stability 311

10.3.2 Ceramic Stability 316

10.3.3 Glass-Encapsulated Ceramic Hybrid Stability 323

10.4 Natural Analogues 324

10.5 Mechanical Properties 328

10.6 Alternative Properties 333

References 334

11. Structural and Modelling Studies 343

11.1 Structural Studies 343

11.1.1 Vitreous Wasteforms 343

11.1.2 Ceramic Wasteforms 349

11.2 Modelling Studies 350

11.2.1 Modelling Techniques 350

11.2.2 Vitreous Wasteforms 350

11.2.3 Ceramic Wasteforms 356

References 357

12. Sources and Compositions of Nonradioactive Toxic and Hazardous Wastes, and Common Disposal Routes 361

12.1 Incinerator Wastes 365

12.2 Sewage and Dredging Sludges 368

12.3 Zinc Hydrometallurgical and Red Mud Wastes 370

12.4 Blast Furnace Slags and Electric Arc Furnace Dusts 370

12.5 Alternative Metallurgical Wastes and Slags 370

12.6 Metal Finishing and Plating Wastes 371

12.7 Coal Ash and Fly Ash from Thermal Power Stations 374

12.8 Cement Dust and Clay-Refining Wastes 379

12.9 Tannery Industry Wastes 379

12.10 Asbestos 380

12.11 Medical Wastes 380

12.12 Electrical and Electronic Wastes 383

12.13 Alternative Wastes 384

References 385

13. Vitrification of Nonradioactive Toxic and Hazardous Wastes 389

13.1 Incinerator Wastes 392

13.2 Sewage and Dredging Sludges 397

13.3 Zinc Hydrometallurgical and Red Mud Wastes 398

13.4 Blast Furnace Slags and Electric Arc Furnace Dusts 399

13.5 Alternative Metallurgical Wastes and Slags 401

13.6 Metal Finishing and Plating Wastes 403

13.7 Coal Ash and Fly Ash from Thermal Power Stations 404

13.8 Cement Dust, Clay-Refining and Tannery Industry Wastes 406

13.9 Asbestos 406

13.10 Medical Waste 407

13.11 Electrical and Electronic Wastes 408

13.12 Alternative Wastes 408

13.13 Mixed Nonradioactive Hazardous Wastes 409

13.14 Glass-Ceramics for Nonradioactive Waste Immobilization 410

13.15 Commercial Hazardous Waste Vitrification Facilities 418

References 420

14. Alternative Treatment Processes, and Characterization, Properties and Applications of Nonradioactive Wasteforms 429

14.1 Alternatives to Vitrification 429

14.2 Use of Alternative Waste Sources to Prepare New Materials 435

14.3 Use of Waste Glass to Prepare New Materials 435

14.4 Characterization, Properties and Applications of Nonradioactive Wasteforms 436

14.4.1 Mechanical Properties 436

14.4.2 Chemical Durability 440

14.4.3 Structural and Modelling Studies 441

14.4.4 Use of Less Hazardous or Nontoxic Surrogates 442

14.5 Applications 444

References 445

15. Influence of Organic, Micro-Organism and Microbial Activity on Wasteform Integrity 451

15.1 Micro-Organism Activity and Transport Mechanisms 452

15.2 Repository Environments 454

15.3 Repository Analogues 457

15.4 Wasteforms 458

References 462

16. Concluding Remarks, Comparisons between Radioactive and Nonradioactive Waste Immobilization, and Outlook for the Future 465

16.1 Mixed Radioactive and Nonradioactive Wastes 465

16.2 System and Wasteform Comparisons 467

16.2.1 Treatment Facilities 467

16.2.2 Wasteforms 469

16.3 Immediate and Short-Term Future Outlook 473

16.4 Medium and Longer Term Future Outlook 474

16.4.1 Generation IV Nuclear Energy Systems 474

16.4.2 Element Partitioning and Transmutation 478

16.5 Choosing a Wasteform 479

16.5.1 Wasteforms Studied in the Past and Short-Term Future Direction 479

16.5.2 Alternative Wasteforms and Longer Term Future Direction 484

16.6 Wasteform Characterization 486

16.7 Standards, Regulatory Requirements, and Performance Assessments 487

16.8 Overall Conclusions 489

References 490

Index 493