2 of 3 United States Department of Energy Office of Waste Management HIGH-LEVEL WASTE BOROSILICATE GLASS A COMPENDIUM OF CORROSION CHARACTERISTICS VOLUME 2 U. S. Department of Energy Office of Waste Management Office of Eastern Waste Management Operations High-Level Waste Division / / G-e:ZAt 7 2 of 3 United States Department of Energy Office of Waste Management HIGH-LEVEL WASTE BOROSILICATE GLASS A COMPENDIUM OF CORROSION CHARACTERISTICS VOLUME 2 U. S. Department of Energy Office of Waste Management Office of Eastern Waste Management Operations High-Level Waste Division HIGH-LEVEL WASTE BOROSILICATE GLASS: A COMPENDIUM OF CORROSION CHARACTERISTICS, VOLUME II Compiled and Edited by: J. C. Cunnane J. K Bates, C. R. Bradley, E. C. Buck, J. C. Cunnane, W. L. Ebert, X. Feng, J. J. Mazer, and D. J. Wronkiewicz Argonne National Laboratory J. Sproull Westinghouse Savannah River Company W. L. Bourcier Lawrence Livermore National Laboratory B. P. McGrail and M. K. Altenhofen Battelle Pacific Northwest Laboratory March 1994 ACKNOWLEDGMENTS Many individuals have contributed to the preparation and review of this document. The authors would like to particularly acknowledge the contributions of the Technical Review Group (TRG), Peer Reviewers who provided technical direction during the preparation of the early drafts, and the document typists (particularly Roberta Riel) who persisted through interminable change cycles. A listing of these individuals appears below: Technical Review Group David E. Clark (Chairman) - University of Florida (USA) Robert H. Doremus - Rensselaer Polytechnic Institute (USA) Bernd E. Grambow - Kernforschungszentrum Karlsruhe (Germany) J. Angwin C. Marples - Atomic Energy Authority (UK) John M. Matuszek - JMM Consulting (USA) Steering Group Rodney C. Ewing - University of New Mexico Aaron Barkatt - The Catholic University of America Denis M. Strachan - Pacific Northwest Laboratory Typists Roberta Riel Norma Barrett Patricia Halerz ii TABLE OF CONTENTS, Volume II LIST OF FIGURES .................................................... vii LIST OF TABLES ..................................................... xi PREFACE ........................................................... xiii GLOSSARY ......................................................... xv LIST OF ACRONYMS .................................................. xxi EXECUTIVE SUMMARY ............................................... xxiii 1.0 INTRODUCTION ................................................ 1 1.1 Techniques for Characterizing Surface Layers .... 3 1.2 Experimental Measures of Waste Glass Corrosion 6 1.3 Standardized Test Methods ................. 7 1.4 Testing Parameters ....................... 10 2.0 WASTE GLASS CORROSION ................... 13 2.1 Characteristics and Effects of Surface Layers. ........ ....13 2.1.1 Formation of Surface Layers during Glass Corrosion ........ .....13 2.1.1.1 Formation of the Diffusion Layer ......... ........ .....13 2.1.1.2 Formation of the Gel Layer ............. ........ ....16 2.1.1.3 Formation of the Precipitated Layer ....... ........ ....17 2.1.2 Characteristics of Surface Layers ................ ........ ....18 2.1.2.1 The Precipitated Layers ................ ........ ... 23 2.1.2.2 Chemical Composition of Surface Layers ........ .. 24 2.1.2.3 Physical Behavior of Surface Layers ....... ........ ... 25 2.1.3 Effects of Surface Layers on Glass Corrosion Rate ........ ... 27 2.1.3.1 Surface Layers as Mass Transport Barriers . ........ .. 27 2.1.3.2 Surface Layer Effects on Glass Dissolution Affinity ...... 34 2.1.4 Summary ................................... ........ ... 36 2.2 Glass Matrix Effects ................................. ........ ... 37 2.2.1 Glass Structure ............................... ........ ... 37 2.2.2 Glass Inhomogeneities .......................... ........ ... 39 2.2.3 Oxidation/Reduction (Redox) State .................. ........ .40 2.2.4 Experimental Observations on the Effects of Glass Composition .... 40 2.2.4.1 Composition Effects in Simple Glasses ............... 40 2.2.4.2 Composition Effects in Nuclear Waste Glasses .......... 43 iii TABLE OF CONTENTS, Volume II (Contd.) 2.2.5 Correlation and Interpretation of Experimental Results ..... 50 2.2.5.1 Free Energy of Hydration (FEH) Model ........ 51 2.2.5.2 Structural Bond Strength Model .............. 53 2.2.5.3 Other Models ........................... 54 2.2.6 Summary .................................... 55 2.3 Effects of Solution Composition, Surface Area-to-Solution Volume, and Flow Rate . 57 2.3.1 S/V Effects in Static Leach Tests .................... 58 2.3.2 Effects of the Flow Rate in Dynamic Leach Tests ........ 66 2.3.3 Results from Tests at Very High S/V Ratios ............ 70 2.3.4 Experimental Measurement of Glass Corrosion Rates ...... 71 2.3.5 Repository Relevance ............................ 74 2.3.6 Summary .................................... 76 2.4 Temperature Effects . 77 2.4.1 SRL 131 Glass . 78 2.4.2 R7T7 Glass. 82 2.4.3 PNL 76-68 Glass . 83 2.4.4 Japanese Waste Glass . 85 2.4.5 European Waste Glasses . 86 2.4.6 Canadian Waste Glasses . 87 2.4.7 Summary . 87 2.5 Effects of Radionuclide Decay . 87 2.5.1 Air and Water Radiolysis ......................... 88 2.5.2 Solid Phase Damage ............................. 89 2.5.2.1 Displacement Damage ..................... 90 2.5.2.2 Ionization Damage ....................... 93 2.5.2.3 Annealing Processes .................... 95 2.5.3 Effects on Glass Durability and Radionuclide Release ..... 98 2.5.4 Summary .................................... 108 2.6 Microbial Effects on Borosilicate Glass Corrosion. 108 2.6.1 Summary . 110 2.7 Radionuclide Release during Glass Corrosion. 110 2.7.1 The Chemistry of Technetium, Uranium, Neptunium, Plutonium, and Americium .................... ....... ....112 2.7.1.1 Standard Reduction Potentials of the Actinides ....... ....112 2.7.1.2 Hydrolysis ......................... ....... ....113 2.7.1.3 Complexation ....................... ....... ....114 2.7.1.4 Solubility .......................... ....... ....121 2.7.2 Radionuclide Behavior in Real Systems ........... ....... ....127 2.7.2.1 Solubility, Speciation, and Complexation in Groundwaters ..................... ....... ....127 2.7.2.2 Interactions with Naturally Occurring Colloids and Mineral Surfaces ........... ....... ....129 2.7.2.3 Retention of Radionuclides by Glass Alteration Phases .................... ....... ....132 iv TABLE OF CONTENTS, Volume II (Contd.) 2.7.3 Colloids .................... ...................... 136 2.7.3.1 Formnation of Colloids .... 136...................... 2.7.3.2 Stability of Colloidal Suspensions ..... .............. 139 2.7.4 Summary .......................................... 140 3.0 WASTE GLASS WEATHERING .......... ........................... 145 3.1 Commercial Glasses ................... ...................... 146 3.2 Historical Glasses .................... ...................... 152 3.3 Natural Glasses .................... ....................... 156 3.4 Static Weathering of HLW Glass ............... ................. 156 3.4.1 Time . .......................................... 157 3.4.2 Temperature ............ ............................ 157 3.4.3 Glass Composition ......... ........................... 159 3.4.4 Volume of Water (Vapor Contact) ......................... 160 3.4.5 Vapor Composition ......... .......................... 160 3.4.6 Radiation ............. ............................. 162 3.5 Interpretation of Experimental Observations on Static Weathering . .162 3.6 Dynamic Weathering of HLW Glass ............. ................ 163 3.7 Radionuclide Release ........................................ 167 3.8 Summary ........................................... 169 4.0 FIELD TESTING AND MATERIALS INTERACTIONS ..... ............... 171 4.1 Field Testing .. 171 4.1.1 Chalk River Program .. 172 4.1.2 Stripa Mine Program .. 172 4.1.3 Hades Facility Test Program .. 174 4.1.4 Ballidon Limestone Program .174 4.1.5 MIIT Program at WIPP .. 174 4.2 Materials Interactions ........................................ 176 4.2.1 Interaction with Stainless Steel .......... .. ............... 176 4.2.2 Interaction with Metals Other than Stainless Steel ........ I ...... 177 4.2.3 Interaction with Packing Materials ......... .. .............. 178 4.2.3.1 Repository Rock ............................... 179 4.2.3.2 Clay ........... ............................ 180 4.3 Summary ........................................... 180 5.0 OBSERVATIONS FROM NATURAL GLASSES ......................... 183 5.1 Basalt Glasses . .......................................... 183 5.2 Rhyolite Glasses ............. .............................. 186 5.3 Tektites ........................................... 190 5.4 Summary ........................................... 190 v TABLE OF CONTENTS, Volume II (Contd.) 6.0 REFERENCES 191 APPENDIX A. WASTE GLASS PRODUCTION AND PROCESS CONTROL .......... 267 A. 1 Description of High-Level Radioactive Waste (HLW) . 267 A.2 Vitrification of Waste . 268 A.3 Waste Acceptance Product Specifications . 270 A.4 Effects of Composition of Melter Feed on Vitrification . 270 A.5 SRS Processing and Process Control. 271 A.5.1 SRS Waste Processingn . 274 A.5.2 SRS Process Controll . 274 A.6 West Valley Processing and Process Control. 278 A.6.1 West Valley Waste Processing. 278 A.6.2 West Valley Process Control. 280 A.7 Hanford Waste Processingg . 280 References for Appendix A ......................... 283 APPENDIX B. SUMMARY BY COUNTRY OF INTERNATIONAL EXPERIENCE.