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Accelerated Glass Reaction Under PCT Conditions

  • W. L. Ebert (a1), J. K. Bates (a1), E. C. Buck (a1) and C. R. Bradley (a1)

Abstract

Static leach tests similar to the PCT were performed for times up to two years to assess the long-term reaction behavior of high-level nuclear waste glasses similar to those expected to be produced at the Defense Waste Processing Facility. These tests show the reaction rate to decrease with the reaction time from an initially high rate to a low rate, but then to accelerate to a higher rate after reaction times of about one year, depending on the glass surface area/leachant volume ratio (SAN) used. The solution concentrations of soluble glass components increase as the reaction is accelerated, while the release of other glass components into solution is controlled by secondary phases which form during the reaction. The net result is that the transformation of glass to stable phases is accelerated while the solution becomes enriched in soluble components that are not effectively contained in secondary phases. The rate becomes linear in time after the acceleration and may be similar to the initial forward rate. A current model of glass reaction predicts that the glass reaction will be accelerated upon the formation of secondary phases which lower the silicic acid solution concentration. These tests show the total silicon concentration to increase upon acceleration of the reaction, however, which may be due to the slightly higher pH that is attained with the acceleration. The sudden change in the reaction rate is likely due to secondary phase formation.

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1. Strachan, D. M., McGrail, B. P., Apted, M. J., Engle, D. W., and Eslinger, P. W., “Preliminary Assessment of the Controlled Release of Radionuclides from Waste Packages Containing Borosilicate Waste Glass,” Battelle Pacific Northwest Laboratory PNL-7591 (1990).
2. Grambow, B., and Lutze, W., “Performance Assessment of Glass as a Long-Term Barrier to the Release of Radionuclides into the Environment,” Mat. Res. Soc. Symp. Proc. 112 (1988).
3. Grambow, B., “A General Rate Equation for Nuclear Waste Glass Corrosion,” Mat. Res. Soc. Symp. Proc. 44, 1524 (1985).
4. Advocat, T., Crovisier, J. L., Fritz, B., and Vernaz, E., “Thermochemical Model of Borosilicate Glass Dissolution: Contextual Affinity,” Mat. Res. Soc. Symp. Proc., 176, 241248 (1990).
5. Petit, J-.C., Magonthier, M. C., Dran, J. C., and Mea, G. Della, “Long-Term Dissolution Rate of Nuclear Waste Glasses in Confined Environments: Does a Residual Affinity Exist?,” J. Mat. Sci. 25, 30483052 (1990).
6. Bourcier, W. L., Peiffer, D. W., Knauss, K. G., McKeegan, K. D., and Smith, D. K., “A Kinetic Model for Borosilicate Glass Dissolution Based on the Dissolution Affinity of a Surface Alteration Layer,” Mat. Res. Soc. Symp. Proc. 176, 209216 (1990).
7. Bourcier, W. L., Weed, H. C., Nguyen, S. N., Nielsen, J. K., Morgan, L., Newton, L., and Knauss, K. G., “Solution Compositional Effects on the Dissolution Kinetics of Borosilicate Glass,” Proc. 4th International Symp. on Water-Rock Interactions (1992, in press).
8. Grambow, B., “What do We Know About Nuclear Waste Glass Performance in the Repository Near Field?,” SKB Technical Report 91-59 (1991).
9. Pederson, L. R., Buckwalter, C. Q., McVay, G. L., and Riddle, B. L., “Glass Surface Area to Solution Volume Ratio and its Implications to Accelerated Leach Testing,” Mat. Res. Soc. Symp. Proc. 15, 4754 (1983).
10. Bates, J. K., Seitz, M. G., and Steindler, M. J., “The Relevance of Vapor Phase Hydration Aging to Nuclear Waste Isolation,” Nucl. Chem. Waste Mgmt. 5(1), 6374 (1984).
11. Ebert, W. L., Bates, J. K., and Bourcier, W. L., “The Hydration of Borosilicate Waste Glass in Liquid Water and Steam at 2000C,” Waste Mgmt. 11, 205221 (1991).
12. Patyn, J., Van Isegham, P., and Timmermans, W., “The Long-Term Corrosion and Modeling of Two Simulated Belgian Reference High-Level Waste Glasses-Part II,” M at. Res. Soc. Symp. Proc. 176, 299-307 (1990).
13. Jantzen, C. M., and Bibler, N. E., “Product Consistency Test (PCT) for DWPF Glass: Part I. Test Development and Protocol,” Savannah River Laboratory Report DPST-87-575 (1987).
14. Ebert, W. L., and Bates, J. K., “A Comparison of Glass Reaction at High and Low SA/V,” Proc. Third Internat. Conf. High-Level Radioactive Waste Mgmt., Vol 1, Las Vegas, NV, 934942 (1992).
15. Bradley, J. P., Germani, M. S., and Brownlee, D. E., “Automated Thin-Film Analysis of Anhydrous Interplanetary Dust Particles in the Analytical Electron Microscope,” Earth and Planet. Sci. Lett. 93, 1 (1989).
16 Buck, E. C., Bates, J. K., Cunnane, J. C., Ebert, W. L., Feng, X., and Wronkiewicz, D. J., “Analytical Electron Microscopy Study of Colloids from Nuclear Waste Glass Reaction,” this volume.
17. Scheetz, B. E., Freeborn, W. P., Smith, D. K., Anderson, C., Zolensky, M., and White, W. B., “The Role of Boron in Monitoring the Leaching of Borosilicate Glass Waste Forms,” Mat. Res. Soc. Symp. Proc. 44, 129134 (1985).

Accelerated Glass Reaction Under PCT Conditions

  • W. L. Ebert (a1), J. K. Bates (a1), E. C. Buck (a1) and C. R. Bradley (a1)

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