Study of Ammonia Adsorption on Magnetite Surfaces with Molecular Dynamics Simulations.

The present study proposes an atomistic molecular dynamics model system of a magnetite (FeO) {111} surface. The effect of temperature on the adsorption process of ammonia (NH) at low concentrations in the aqueous phase has been considered. The molecular dynamics simulations were carried out using the Clay force field (Clay FF) with a modification for the iron atoms in the NPT ensemble at a pressure of 90 bar.

Corrosion Mechanism and Electrochemical Reactions on Alloy 690 in Simulated Primary Coolant of Water-Water Energy Reactors.

During the power operation of the primary loop of a water cooled-water moderated energy reactor (WWER), the water chemistry evolves from a high-boron high-potassium composition to significantly lower concentrations of both constituents at the end of a campaign, and the Li concentration reaches ca. 0.7-0.

Corrosion of Stainless Steel in Simulated Nuclear Reactor Primary Coolant-Experiments and Modeling.

In the present paper, the effect of the evolution of primary water chemistry during power operation on the corrosion rate and conduction mechanism of oxide films on stainless steel is studied by in situ impedance spectroscopy at 300 °C/9 MPa during 1-week exposure periods in an autoclave connected to a recirculation loop. At the end of the exposure period, the samples were anodically polarized in a wide range of potentials to evaluate the stability of the passive oxide. Separate samples of the same steel were simultaneously exposed to the coolant and subsequently analyzed by glow discharge optical emission spectroscopy (GDOES) in order to estimate the thickness and the in-depth composition of the formed oxides.

Anodic Oxidation of Tungsten under Illumination-Multi-Method Characterization and Modeling at the Molecular Level.

Tungsten oxide has received considerable attention as photo-anode in photo-assisted water splitting due to its considerable advantages such as significant light absorption in the visible region, good catalytic properties, and stability in acidic and oxidative conditions. The present paper is a first step in a detailed study of the mechanism of porous WO growth via anodic oxidation. In-situ electrochemical impedance spectroscopy (EIS) and intensity modulated photocurrent spectroscopy (IMPS) during oxidation of W illuminated with UV and visible light are employed to study the ionic and electronic processes in slightly acidic sulfate-fluoride electrolytes and a range of potentials 4-10 V.

Long-Term Oxidation of Zirconium Alloy in Simulated Nuclear Reactor Primary Coolant-Experiments and Modeling.

Oxidation of Zr-1%Nb fuel cladding alloy in simulated primary coolant of a pressurized water nuclear reactor is followed by in-situ electrochemical impedance spectroscopy. In-depth composition and thickness of the oxide are estimated by ex-situ analytical techniques. A kinetic model of the oxidation process featuring interfacial reactions of metal oxidation and water reduction, as well as electron and ion transport through the oxide governed by diffusion-migration, is parameterized by quantitative comparison to impedance data.