Chemistry of Glass "Part 12": Glass Reactivity with Allowance for the Alteration Layer "GRAAL".

Initially created by researchers of the French Alternative Energies and Atomic Energy Commission (CEA), GRAAL is an empirical model of glass modification. The production of the passivating layer by hydration of the glass, the flow of water through this layer, its dissolution by the external face, and the precipitation of crystalline secondary phases; are the four primary mechanisms of glass alteration described by GRAAL glass.

East entrance of CEA Paris-Saclay

The equations include four parameters that we mentioned earlier, to deal with transportation and simulation of complex systems and chemical couplings, these equations are incorporated into a geochemical code. In basic circumstances, analytical solutions are also possible.
The alteration of the blocks will only be slightly impacted over time by the crack network. This is what research on this model has revealed. The fastest possible disintegration of the exterior surfaces subjected to a continuous replenishment of water controls the alteration of these blocks.
The resemblance of the interactions with nuclear glasses was demonstrated by a mechanistic and kinetic research, which also allowed for defining parameters of the model for this type of glass.

When there is no thermodynamic equilibrium, chemical couplings/transfers on material durability are very important. This, in short, is what this study shows.

References:

• Peter C. Rieke, Sebastien Kerisit, Joseph V. Ryan, James J. Neeway, Adaptation of the GRAAL model of Glass Reactivity to accommodate non- linear diffusivity. Journal of Nuclear Materials. Volume 512. 2018. Pages 79-93, ISSN 0022-3115
• Glass and Ceramic Technology Course (2021). Professor Khelifa- Department of Materials Process Engineering- University of Mostaganem. Algeria.
• Les matériaux au cœur du processus d'innovation- Clefs CEA No 59.
• Neumann, Florin. "Glass: Liquid or Solid – Science vs. an Urban Legend". Archived from the original on 9 April 2007. Retrieved 8 April 2007.