Numerical Simulation of Atmospheric Carbonation of Concrete Components in a Deep Geological Radwaste Disposal Site During Operating Period

AbstractSimulations of atmospheric carbonation of concrete intermediate-low level waste cell components were conducted to evaluate potential chemical degradations affecting these components during the operating period of a radioactive waste repository in a deep Callovo-Oxfordian clay layer. Two-phase liquid water-air flow is combined with gas components diffusion processes, leading to a progressive drying of the concrete and an array of chemical reactions affecting the cement paste. The carbonation process depends strongly on the progression of the drying front inside the concrete, which in turn is sensitive to the initial water saturation and to nonlinear effects associated with permeability and tortuosity phenomenological laws.Results obtained with a modified version of ToughReact-EOS4 to represent realistic tortuosity evolution of materials with clogging and saturation are presented and commented upon. Strong porosity clogging of the carbonated concrete is not observed in the simulations; slight porosi...