Nuclear glass alteration bridging the gap from surface reactivity description to reactive transport at the scale of the fractured block

M. Repina (1) , F. Bouyer (1) , Vincent Lagneau (2) , Didier Renard (2)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
2 GEOSCIENCES - Centre de Géosciences

The complete workflow comprising the steps of image analysis, tessellation construction and upscaling of permeability and diffusion coefficients is elaborated in order to prepare an equivalent mathematical model of a nuclear glass package at scale 1 for further reactive transport modelling. The workflow asks as input the pre-prepared grayscale image and progresses through five stages- (i) fracture network extraction, (ii) image segmentation and fracture aperture measuring, (iii) crystals ' anisotropy characterization, (iv) construction of an equivalent tessellation and (v) determination of equivalent fields of permeability and diffusion. Images of the longitudinal cross-sections of two specimens of non-radioactive packages of vitrified glass are used as a testbed for this study. Imaged packages were produced at the Vitrification Production Facilities in Marcoule in a cold crucible induction melter, with UOx package being a close analogue of the French R7T7 nuclear glass.We provide the implementation of the complete routine and demonstrate the results obtained via the image analysis and steps of upscalling.

Keywords: reactive transport; fracture network; glass alteration; fracturing; alteration; transport

Domains: Physics [physics]; Nuclear Experiment [nucl-ex]; Physics [physics]; Nuclear Theory [nucl-th]

M. Repina, F. Bouyer, Vincent Lagneau, Didier Renard. Nuclear glass alteration bridging the gap from surface reactivity description to reactive transport at the scale of the fractured block. Computational Methods in Water Resources (CMWR ), Jun 2018, Saint Malo, France. ⟨cea-02339284⟩