Modeling glass corrosion with GRAAL. (December 2018)

• Record Type: Journal Article
• Authors: Frugier, Pierre; Minet, Yves; Rajmohan, Natarajan; Godon, Nicole; Gin, Stéphane
• Is Part Of: Npj Materials degradation. Volume 2(2018)
• Page Start: 1
• Page End: 13
• Publication Date: 2018-12
• Subjects: Materials -- Deterioration -- Periodicals; Materials -- Testing -- Periodicals; 620.110287
• DOI: 10.1038/s41529-018-0056-z
• Languages: English
• ISSNs: 2397-2106

Abstract

Abstract Computational codes are necessary tools for geochemical modeling of the alteration of minerals due to their ability to handle key mechanisms, such as dissolution, precipitation, diffusion, and convection at many temporal and spatial resolutions. Modeling glass corrosion specifically requires a description of the amorphous layer that forms on the surface of the glass and its effect on glass alteration kinetics. The objective of the GRAAL model (glass reactivity in allowance of the alteration layer) is both to provide a simple implementation of the passivation process in a reactive transport code and to provide data relative to the composition and the solubility of the amorphous layer. The size and properties of the protective amorphous layer drives the glass alteration rate, with regard to passivation; the greater the quantity of the protective amorphous layer, the lower the dissolution rate of the primary mineral. Here, concepts, equations, and implementation of GRAAL are reported. Simple glass alteration experiments are used to apply the model and measure parameters. The International Simple Glass used for nuclear glass long-term behavior studies is at the center of the glass compositions studied. Nuclear glass: Model behaviour The development of a glass corrosion model has been described, highlighting its implementation, recent improvements and its limitations. Glass corrosion is a complex chemical process that involves the formation of an amorphous passivating layer on the surface of the glass that significantly affects subsequent glass alteration kinetics. Modelling can provide an insight into the complex chemistry at play that is difficult to observe experimentally and a model known as the 'glass reactivity with allowance for the alteration layer' (GRAAL) model has been developed to do just that. Now, a team led by Pierre Frugier at the CEA, Marcoule, France have presented a detailed description of GRAAL, focussing on the kinetic equations, its implementation in a reactive transport code, parameter selection and its efficiency and limitations.