Molecular dynamics simulations of supercritical water at the iron hydroxide surface

•Supercritical water–iron (II) hydroxide crystal interface was studied.•Atomic density profiles were obtained.•Localized adsorption and surface clustering of supercritical water was found.

The adsorption properties of supercritical water confined between electrostatically neutral but hydrophilic surfaces of iron (II) hydroxide were determined through molecular dynamics simulations. Simulations were conducted at temperatures of 715, 814 and 913 K, and at water densities typically found in the heat transport system of the supercritical water cooled nuclear reactor (SCWR). Surface water layer densities were obtained and compared to those of the bulk water. Adsorption coverage was calculated as a function of the number of waters per OH group on the surface. Images of the water molecules configurations are provided along with the density profile of the adsorption layer. The localized adsorption and surface clustering of supercritical water, as seen in this study, would likely produce more localized corrosion phenomena in the water bearing components of the SCWR.

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