In France, some of nuclear waste are packaged in stainless steel containers and stored in above-
ground storage facilities. These waste packages are likely to remain in interim storage for a period
of several decades before being moved to an underground facility for permanent disposal.
Atmospheric aerosols will deposit on the container surfaces, in particular in marine atmospheres,
where sprayed droplets are carried by the wind from the sea. The droplet deposits on the exposed
surface and becomes saline sessile droplet. This creates an electrolyte of finite size that can react
with the metallic surface, leading to atmospheric corrosion.
Moreover due to the day/night cycles, a variation of the relative humidity and the temperature
cannot be excluded and can lead to the morphological change of the droplet especially to its
evaporation. Those cycles can increase the corrosion phenomena [1]. And the residues that droplets
leave at the end of evaporation are important to consider, since they testify to the presence of
complex mechanisms taking place within such a drop [1, 2]. Therefore, studying the impact of
atmospheric pollutants inside evaporating droplets is a major economic challenge
to understand their impact on the lifetime of materials.
The aim of our work is to develop a numerical analysis of the corrosion under droplet. In order to
investigate the effect of evaporation on corrosion, we study dynamic sessile droplets. We propose a
numerical model of evaporation dynamics of salty sessile drops, built with Basilisk, a free software
which implements finite volume methods for the Navier-Stokes equations [3]. Because of the
complexity of the problem, the model was developed step by step. At first we were interested in the
evaporation of sessile droplets of water deposited on non-corrodable substrat in order to understand
the dynamics of evaporation on a simple case. In a second step, we looked at the influence of the
salt to identify the potential sites of corrosion appearance.

References
[1] Robert D. Deegan et al. "Capillary flow as the cause of ring stains from dried liquid drops."
Nature, 1997.
[2] François Boulogne, François Ingremeau, and Howard A. Stone. "Coffee-stain growth dynamics
on dry and wet surfaces." Journal of Physics : Condensed Matter, 2017.
[3] Stéphane Popinet. "An accurate adaptive solver for surface-tension-driven interfacial flows."
Journal of Computational Physics, 2009.