This project focuses on the computational design of novel coating alloys for nuclear fuel rods, contributing to the Coated Nuclear Fuel Rods (FurCoat) consortium. The primary objective is to investigate the oxidation and corrosion resistance of refractory alloys under extreme environments using first-principles simulations. By employing density functional theory (DFT) calculations in combination with thermodynamic modeling, we aim to construct Ellingham and Pourbaix diagrams to systematically assess phase stability, oxidation kinetics, and corrosion mechanisms. To capture the effects of temperature and disorder, we will integrate ab initio molecular dynamics (AIMD) and disordered local moment molecular dynamics (DLM-MD) approaches. AIMD simulations, particularly when combined with machine learning interatomic potentials, will allow an accurate estimation of free energy at elevated temperatures. Meanwhile, the DLM-MD method will incorporate finite-temperature magnetic fluctuations into the calculations, improving the description of phase stability for magnetic alloys. Additionally, atomistic spin dynamics (ASD) coupled with AIMD will be used to evaluate the coupling between spin and lattice degrees of freedom in materials where magnetism plays a critical role. The computational data generated in this project will be integrated into the HADB database (https://hadb.funmat-ii.se/), ensuring accessibility for the research community. By systematically studying the oxidation and corrosion behavior of multicomponent alloys, the project aims to provide theoretical insights that can guide experimental alloy development for nuclear fuel applications.