Abstract
Uranium disilicide \((\text{U}_3\text{Si}_{2})\) is emerging as a promising accident tolerant nuclear fuel candidate for Advanced Light Water Reactors (ALWR) due to its high fissile element density and superior thermal conductivity, which offer significant advantages under normal operational and accident conditions. However, due to its sensitive oxidation and corrosion properties in air and steam environments, its use as a potential reactor fuel is limited. In recent years, various alloying elements, including Cr and Al, have been shown to create passive compounds such as \(\text{Cr}_2\text{O}_{3}\) and \(\text{Al}_2\text{O}_3\) , which can act as a protective layer to prevent oxidation. In this study, we have used Hubbard-corrected density functional theory (DFT+U) to systematically investigate the adsorption and dissociation behavior of water molecule on the pure and Al-doped \(\text{U}_3\text{Si}_{2}\) {001}surfaces to understand the early stage of surface oxidation in presence of steam. The study mainly focuses on different water adsorption configurations, energetics, and dissociation behavior, which is very crucial to provide the fundamental insights into improved corrosion resistance mechanisms of accident tolerant uranium disilicide fuel material in presence of aluminum.
Graphic abstract
Adsorption behaviour of water over pure and Al-doped U3Si2 {001} surfaces has been investigated using density functional theory (DFT) studies. A detailed insight into the adsorption mechanism has been explored through the calculations of adsorption energetics, density of states and charge transfer between the adsorbent and adsorbate.
