Hostname: page-component-586b7cd67f-gb8f7 Total loading time: 0 Render date: 2024-11-26T16:04:47.019Z Has data issue: false hasContentIssue false
  • English
  • Français

Thermochemical Modeling of Glass: Application to High-Level Nuclear Waste Glass

Published online by Cambridge University Press:  29 November 2013

Karl E. Spear ,
Theodore M. Besmann  and
Edward C. Beahm
Get access

Extract

Despite the obvious importance of understanding the chemistry of oxide glass materials, predictive thermochemical modeis of complex glasses have not yet been developed. Such modeis are important for technologies such as the disposal of high-level nuclear and transuranic waste (HLW), which are currently fore-seen as being incorporated in a host glass for permanen t Sequestration. A large number of glasses have been explored, with a borosilicate glass being the typical base composition. An example of the complexity of such a HLW glass is given in Table I. This article discusses our at-tempts to develop an accurate, easy to understand and use glass Solution model for describing the thermodynamic stability of such HLW glasses. Critical for such a model is the availability of reliable thermodynamic data that can be used in generating accurate values for thermodynamic activities of glass components as a function of temperature and glass composition. Therefore, a major part of this article focuses on developing reliable sets of thermodynamic data for complex HLW glass Systems and Subsystems. With such Information and a model, we can make predictions of the stability of these waste forms, including their volatility, leaching behavior, and corrosion reactions, and understand crystallization behavior during both the initial glass processing and long-term storage.

Using an equilibrium thermodynamic model is offen questioned, since HLW is to be stored as part of a glass phase, and glass is a nonequilibrium material. Our model uses a pseudoequilibriu map-proach in which we thermochemically treat the glass as a supercooled liquid. This is a more accurate approach than assuming a global System equilibrium, as it describes the behavior of the metas-table glass phase using thermodynamic data for the liquid phase and excludes the formation of crystalline species. As a result, developing an accurate model and data for representing the thermodynamic properties of oxide liquid phases is critical to understanding the limiting chemi-cal behavior of the nuclear waste glass.

The methodology requires that a critically assessed thermodynamic database be created for binary and ternary combinations of the major constituents in a typical waste glass. These data can then be combined to represent the thermodynamic behavior of the more complex multicomponent HLW glass Systems. If a crystalline phase is experimentally observed to precipitate from the glass under certain conditions, a thermodynamic description can be used to calculate the composition-temperature conditions under which this specific crystalline phase can exist in equilibrium with the metas-table glass phase.

Type
Computer Simulations from Thermodynamic Data: Materials Production and Development
Information
MRS Bulletin , Volume 24 , Issue 4 , April 1999 , pp. 37 - 44
Copyright
Copyright © Materials Research Society 1999

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1.Ellison, A.J.G. and Navrotsky, A., in Scientific Basis for Nuclear Waste Management XIII, edited by Oversby, V.M. and Brown, P.W. (Mater. Res. Soc. Symp. Proc. 176, Pittsburgh, 1990) p. 193.Google Scholar
2.Jantzen, C.M., in Corrosion of Glass, Ceramics, and Ceramic Superconduclors, edited by Clark, D.E. and Zoitos, B.K. (Noyes Publications, Park Ridge, NJ, 1992) p. 153.Google Scholar
3.Eriksson, G. and Hack, K., Metall. Trans. B 21 (1990) p. 1013; ChemSage™, Version 4.1 (GTT Technologies, Herzogonrath, Germany, 1998).CrossRefGoogle Scholar
4.SGTE Pure Substance Database, 1996 Version; produced by the Scientific Group Thermodata Europe and obtained through GTT Technologies (see Reference 3).Google Scholar
5.Phase Diagrams for Ceramists, vols. 1–12 (The American Ceramic Society, Westerville, OH, 1964–1996).Google Scholar
6.Eriksson, G., Wu, P., and Pelton, A.D., CAL-PHAD 17 (2) (1993) p. 189.Google Scholar
7.Wu, P., Eriksson, G., and Pelton, A.D., J. Am. Ceram. Soc. 76 (8) (1993) p. 2059.CrossRefGoogle Scholar
8.Eriksson, G. and Pelton, A.D., Metall. Trans. B 24 (1993) p. 807.CrossRefGoogle Scholar
9.Spear, K.E., Besmann, T.M., and Beahm, E.C., in Proc. High Temperature Corrosion and Materials Chemistry, vol. 98–9, edited by Hou, P.Y., McNallan, M.J., Oltra, R., Opila, E.J., and Shores, D.A. (The Electrochemical Society, Pennington, NJ, 1998) p. 512.Google Scholar
10.Spear, K.E., in Treatise on Solid State Chemistry, vol. 4, Chapter 3, edited by Hannay, N.B. (Plenum, New York, 1976) p. 115.CrossRefGoogle Scholar
11.Hastie, J.W. and Bonnell, D.W., High Temp. Sci. 19 (1985) p. 275.Google Scholar
12.Hastie, J.W., Pure Appl. Chem. 56 (1984) p. 1583.CrossRefGoogle Scholar
13.Hastie, J.W., Plante, E.R., and Bonnell, D.W., Vaporization of Sinuilated Nuclear Waste Glass (NIST, Gaithersburg, MD, NBSIR 83–2731, 1983).Google Scholar
14.Bonnell, D.W. and Hastie, J.W., High Temp. Sci. 26 (1990) p. 313.Google Scholar
15.Spear, K.E., Benson, P., and Pantano, C.G., in High Temperature Materials Chemistry IV, edited by Munir, Z.A., Cubicciotti, D., and Tagawa, H. (The Electrochemical Society, Pennington, NJ, 1988) p. 345.Google Scholar
16.Pantano, C.G., Spear, K.E., Qi, G., and Beall, D.M., in Trans. Advances in Ceramic-Matrix Composites, vol. 38, edited by Bansal, N. (The American Ceramic Society, Westerville, OH, 1993) p. 173.Google Scholar
17.Paulson, T.E., Spear, K.E., and Pantano, C.G., in Proc. High Temperature Materials Chemistry IX, vol. 97–39, edited by Spear, K.E. (The Electrochemical Society, Pennington, NJ, 1997) p. 194.Google Scholar
18.Paulson, T.E., Spear, K.E., and Pantano, C.G., “Thermodynamic Analysis of the Tin Penetration Profile in High-Iron Float Glass,” in Proc. Int. Congress on Class, Summer 1998 (The American Ceramic Society, Westerville, OH, 1998).Google Scholar
19.Pelton, A.D. and Blander, M., Metall. Trans. B 17 (1986) p. 805.CrossRefGoogle Scholar
20.Blander, M. and Pelton, A.D., Geochim. Cos-mochim. Acta 51 (1987) p. 85.CrossRefGoogle Scholar
21.Pelton, A.D., Pure Appl. Chem. 69 (11) (1997) p. 2245.CrossRefGoogle Scholar
22.Besmann, T.M., Beahm, E.C., and Spear, K.E., in Ceramic Trans. Environmental Issues and Waste Management Technologies in the Ceramic and Nuclear Industries IV, vol. 93, edited by Marra, J.C. and Chandler, G.T. (The American Ceramic Society, Westerville, OH, 1999).Google Scholar
23.Spear, K.E., Palmisiano, M.N., Pantano, C.G., Besmann, T.M., and Beahm, E.C., in Proc. Fundamental Gas-Phnse and Surface Chemistry of Vapor-Phase Materials Synthesis, vol. 98–23. edited by Mountziaris, T.J., Allendorf, M.D., Jensen, K.F., Ulrich, R.K., Zachariah, M.R., and Meyyappan, M. (The Electrochemical Society, Pennington, NJ, 1999).Google Scholar
24.Hoch, M., J. Phase Equilibrin 17 (4) (1996) p. 290.CrossRefGoogle Scholar
25.Li, H., Vienna, J.D., Hrma, P., Smith, D.E., and Schweiger, M.J., in Scientific Basis for Nuclear Waste Management XX, edited by Gray, W.J. and Triay, I.R. (Mater. Res. Soc. Symp. Proc. 465, Pittsburgh, 1997) p. 261.Google Scholar
26.Mika, M., Schweiger, M.J., Vienna, J.D., and Hrma, P., in Scientific Basis for Nuclear Waste Management XX, edited by Gray, W.J. and Triay, I.R. (Mater. Res. Soc. Symp. Proc. 465, Pittsburgh, 1997) p. 71.Google Scholar