--. 7 I ! ! (OBI-Q a a ~~A. g(iM'1C~ MDIaWPP ~- [' s 0 t234 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Governmentnor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commerical product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendations, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do notnecessarily state or reflect those of the United States Government or any agency thereof. This report has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831; prices available from (615) 576-8401. Available to the public from the U.S. Department of Commerce, Technology Administra- tion, National Technical Information Service, Springfield, VA 22161. (703) 4874650. Pmrneed MtSoyr ,k on recyCled paper DOE-EM-01 77 Vol.1 of 3 United States Department of Energy Office of Waste Management HIGH-LEVEL WASTE BOROSILICATE GLASS A COMPENDIUM OF CORROSION CHARACTERISTICS VOLUME 1 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 I 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. Granbow - Kernforschungszentrum Karlsruhe (Germany) J. Angwin C. Marples - Atomic Energy Authority (UK) John M. Maruszek - JMM Consulting (USA) Steering Group Rodney C. Ewing - University of New Mexico Aaron Barkatt - The Catholic University of America Denis Strachan - Pacific Northwest Laboratory Typists Roberta Riel Norma Barrett Patricia Halerz ii TABLE OF CONTENTS, Volume I LIST OF FIGURES .................................................... v LIST OF TABLES ..................................................... vii PREFACE . .......................................................... ix GLOSSARY ......................................................... xi LIST OF ACRONYMS .................................................. xvii EXECUTIVE SUMMARY ............................................... xix 1.0 INTRODUCTION ................................................ 1 1.1 Objective, Scope, and Organization ............. .. ............... I 1.1.1 Objective ........................................... 1 1.1.2 Scope ........................................... 2 1.1.3 Organization ........................................ 2 1.2 Overview of Borosilicate Waste Glass Corrosion ..... ........ 2 1.2.1 Glass Corrosion Reactions ............................... 3 1.2.2 Glass Corrosion Reaction Kinetics ......................... 4 1.2.3 Glass Corrosion in an Underground Repository ................ 8 1.2.4 Significance of Glass Corrosion and Radionuclide Release Rate Data .................................... 10 1.3 History of Glass as a Waste Form ............................... 12 1.4 International Experience Overview ............. .. ................ 13 2.0 DESCRIPTION OF BOROSILICATE WASTE GLASS AND ENVIRONMENTAL CONDITIONS OF INTEREST ....................................... 19 2.1 Description of Waste Glass Products ....... ...................... 19 2.1.1 Waste Glass Compositions ....... ....................... 19 2.1.2 Other Waste Glass Characteristics ...... ................... 19 2.1.2.1 Redox State .................................. 19 2.1.2.2 Characteristics Produced during Cooldown .... ........ 25 2.1.2.3 Canistered Waste Heat Output and Radioactivity .... .... 28 2.2 Environmental Conditions of Interest ....... ...................... 34 2.2.1 Conditions during Storage and Transportation .............. ... 34 2.2.1.1 Temperature during Storage and Transportation .... ...... 35 2.2.1.2 Canister Fill Gas ............................... 35 iii TABLE OF CONTENTS, Volume I (Contd.) 2.2.2 Disposal Conditions in Saturated Geologic Environments .... ..... 35 2.2.2.1 Temperature ........ .......................... 36 2.2.2.2 Pressure .......... ........................... 37 2.2.2.3 Hydrological Conditions ......................... 37 2.2.2.4 Geochemical Conditions ......................... 38 2.2.3 Disposal Conditions in Unsaturated Geologic Settings .... ....... 39 2.2.3.1 Unsaturated Hydrologic Conditions ..... ............. 40 2.2.3.2 Temperature ........ .......................... 42 2.2.3.3 Vapor Phase and Associated Radiation Effects .... ...... 42 2.2.3.4 Groundwater Chemistry .......................... 42 3.0 BOROSILICATE WASTE GLASS CORROSION ......................... 45 3.1 Corrosion Processes ......................................... 45 3.1.1 Aqueous Corrosion ................. ................... 45 3.1.2 Waste Glass Weathering ............... ................. 49 3.2 Controls on the Glass Corrosion Rate and Release Rates of Components .. .51 3.2.1 Corrosion Rate .. 51 3.2.2 Release Rates of Components .57 3.3 Modeling of Glass Corrosion Rate and Associated Radionuclide Release Rates .. .59 3.3.1 General Overview ................ ................... 60 3.3.2 Approaches to Modeling Glass Corrosion Rate ....... ......... 60 3.3.2.1 Models Based on Diffusion Control ..... ............ 60 3.3.2.2 Models Based on Dissolution Control ..... ........... 61 3.3.3 Natural Analogues and Model Validation ....... .. ........... 72 3.3.4 Linkage between Models of Glass Corrosion Rate and Repository Performance Assessment Models ........ .......... 72 4.0 SUMMARY OF UNCERTAINTIES ................................... 75 4.1 Uncertainties in Waste Glass Corrosion and Weathering .... ............ 75 4.2 Uncertainties in Radionuclide Release Rates .......................... 77 4.3 Significance of Remaining Uncertainties .78 5.0 REFERENCES ........................................... 81 APPENDIX A. Composition for Reference Nuclear Waste Glasses . .107 APPENDIX B. Radioactivity of Actinide, Fission Product, and Activation Product Radionuclides in Waste Glass .121 iv LIST OF FIGURES No. Title Page 1-1. Schematic of Surface Layers on Corroded Glass. 5 1-2. Schematic Showing Qualitative Behavior of Glass Corrosion vs. Time. 7 1-3. Schematic of HLW Borosilicate Glass Corrosion Following Geologic Disposal 9 1-4. Logarithm of the Retention Factors for Actinides Released from R7T7 Glass at 90'C 11 2-1. Ternary Diagram Depicting Compositional Similarities for a Variety of Glasses that were Tested in the Waste Isolation Pilot Plant .24 2-2. Schematic of the DWPF Canistered Waste Showing Nominal Physical Characteristics 26 2-3. Temperature Ranges that Correspond to Potential Changes in Waste Glass Physical Properties ............................................... 26 2-4. Relationship Between Percent Pore Saturation and Relative Humidity for Hydrologic Unit II-NL of Topopah Springs Tuff of 10% Porosity .41 3-1. Schematic Profile through Reacted Glass Layers, Including Concentration Profiles of Selected Elements Obtained Using SIMS; SIMS Profiles of SRS Simulated DWPF Glass After Two Years of Burial in the WIPP-MIlIT Tests .46 3-2. Resonant Nuclear Reaction Hydrogen Concentration Depth Profiles in Reacted Soda-Lime-Silica Glass as a Function of Time .48 3-3. Rate Constant for SRL 165 Simple Analog Glass vs. pH at 25, 50, and 70'C Measured in Flow-Through Apparatus ........... ............... 49 3-4. Boron Release after 28 Days of Leaching of PNL 76-68 Glass at 90 0C in Solutions of Varying Initial Silica Concentrations .......................... 53 3-5. Plot of Extent of Reaction vs. Time for Sodium Silicate Glass Reacted in HCl Solution at Constant pH in Both HO and D2 0 Solutions .... ............. 54 3-6. Silica Release Data for SRL 165 Glass Reacted at 1500C in 0.003 M NaHCO3 Solution ................. 58 v LIST OF FIGURES (Contd.) No. Title Page 3-7. Typical Normalized Element Release Profiles for SRL-165SA Glass Reacted 1 . at 150'C in 0.003 M NaHCO 3 Solution with S/V = 0.01 cm 62 3-8. Schematic Illustration of the Evolution of Surface Layers on Reacting Glass .63 3-9. Predicted vs. Measured Concentrations of Elements Leached from JSS-A Glass at 90 0C in Deionized Water vs. Time in Days; Surface Area to Volume Ratio of 10 m- 67 3-10. Predicted vs. Measured Concentrations of