Albite (NaAlSiO), a framework silicate of the plagioclase feldspar family and a common constituent of felsic rocks, is often present in the siliceous mineral aggregates that compose concrete. When exposed to radiation (e.g., in the form of neutrons) in nuclear power plants, the crystal structure of albite can undergo significant alterations. These alterations may degrade its chemical durability. Indeed, careful examinations of Ar-implanted albite carried out using Fourier transform infrared spectroscopy (FTIR) and molecular dynamics simulations show that albite's crystal structure, upon irradiation, undergoes progressive disordering, resulting in an expansion in its molar volume (i.e., a reduction of density) and a reduction in the connectivity of its atomic network. This loss of network connectivity (i.e., rigidity) results in an enhancement of the aqueous dissolution rate of albite-measured using vertical scanning interferometry (VSI) in alkaline environments-by a factor of 20. This enhancement in the dissolution rate (i.e., reduction in chemical durability) of albite following irradiation has significant impacts on the durability of felsic rocks and of concrete containing them upon their exposure to radiation in nuclear power plant (NPP) environments.

On the basis of systematic experimental interrogation of the aqueous dissolution behavior of a large selection of minerals, whose dissolution rates vary by several orders of magnitude, this study demonstrates that acoustic perturbation yields an unprecedented enhancement in dissolution kinetics, which scales with the mineral's hardness and average bond energy. The dissolution enhancement produced is described by an Arrhenius-like formulation that reveals the energy imparted to the solute's surficial atoms by sonication. From an energy landscape perspective, it is highlighted that sonication perturbs surficial solute atoms from their equilibrium positions. As a result, upon contact with a solvent, sonicated atoms need a smaller amount of energy for dissolution to occur by bond rupture. Therefore, the activation energy of dissolution under sonication is consistently smaller than that under sonication-free conditions. Altogether, this study suggests that the enhancement in mineral dissolution over the course of acoustic perturbation under macroscopically isothermal conditions results from the excitation of the surficial atoms and is negligibly associated with temperature rise or surface area amplification as has been previously suggested.

Nanoscale-resolved quantifications of almandine's (Fe 3 Al 2 (SiO 4 ) 3 ) dissolution rates across a range of pHs (1 ≤ pH ≤ 13)established using vertical scanning interferometryreveal that its dissolution rate achieves a minimum around pH 5. This minimum coincides with almandine's point of zero charge. These trends in almandine's dissolution can be estimated using the Butler−Volmer equation that reveals linkages between surface potentials and dissolution rates, demonstrating proton-and hydroxyl-promoted breakage of Si−O bonds. In contrast to well-polymerized silicates, the dissolution of almandine can also occur through the rupture of its cationic bonds. This behavior is reflected in the observed influences of irradiation on its dissolution kinetics. Molecular dynamics simulations highlight that irradiation induces alterations in the atomic structure of almandine by reducing the coordination state of the cations (Fe 2+ and Al 3+ ), thereby enhancing its reactivity by a factor of two. This is consistent with the minor change induced in the structure of almandine's silicate backbone, whose surface charge densities produce the observed pH dependence (and rate control) of dissolution rates. These findings reveal the influential roles of surface potential arising from solution pH and atomic scale alterations on affecting the reactivity of garnet-type silicates.

When exposed to irradiation-e.g., in nuclear power plant environments-minerals may experience alterations in their atomic structure which, in turn, result in changes in their physical and chemical properties. Herein, we mimic via Ar + implantation the effects of neutron irradiation on calcite (CaCO 3 ) and dolomite (CaMg(CO 3 ) 2 )two carbonate minerals that often find use as aggregates in concrete: a material that is extensively used in the construction of critical structural and safety components in nuclear power plants. By a pioneering combination of nanoscale quantifications of mineral dissolution rates (i.e., a proxy for chemical durability) in alkaline solutions, vibrational (infrared and Raman) spectroscopy, and molecular simulations, we find that irradiation minimally affects the atomic structure and properties of these carbonate minerals. This insensitivity to radiation arises from the predominantly ionic nature of the interatomic bonds in these minerals which can relax and recover their initial configuration, thus ensuring minimal damage and permanent alterations to these minerals following radiation exposure. The outcomes have significant implications on the selection, use, and specification of mineral aggregates for use in nuclear concrete construction.