Modeling of concrete carbonation in deep geological disposal of intermediate level waste

P. Thouvenot (1) , Olivier Bildstein (1) , I. Munier (2) , B. Cochepin (2) , Stéphane Poyet (1) , X. Bourbon (2) , E. Treille (2)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
2 ANDRA - Agence Nationale pour la Gestion des Déchets Radioactifs

Simulations of atmospheric carbonation of Intermediate-Level Long-lived radioactive Waste (ILLW) concrete packages were conducted to evaluate their possible chemical degradations. Two-phase liquid water-air flow is combined with gas component diffusion processes leading to a progressive drying of the concrete. Complete drying of the 11 cm thick waste disposal package wall occurs over a period ranging from 2 years for the low-performance concrete to 10 years for the high-performance concrete. The drying process slows down when transport characteristics of concretes are enhanced. Carbonation depths in the order of 2 to 3 cm in 100 years are predicted for this cementitious component. However, these values are slightly overestimated compared to experimental data. Also the kinetic model of mineral reactivity requires improvements with respect to the protective effect of secondary carbonates and to thermodynamic data.

Domaines: Géologie appliquée; Matériaux

P. Thouvenot, Olivier Bildstein, I. Munier, B. Cochepin, Stéphane Poyet, et al.. Modeling of concrete carbonation in deep geological disposal of intermediate level waste. EPJ Web of Conferences, 2013, International Workshop NUCPERF 2012: Long-Term Performance of Cementitious Barriers and Reinforced Concrete in Nuclear Power Plant and Radioactive Waste Storage and Disposal (RILEM Event TC 226-CNM and EFC Event 351), 56, pp.05004. ⟨10.1051/epjconf/20135605004⟩. ⟨hal-02866058⟩