The increasing use of recycled steel scrap is essential for reducing the environmental footprint of steel production. However, repeated recycling results in the accumulation of tramp elements such as copper (Cu), tin (Sn), phosphorus (P), and antimony (Sb), which are difficult to remove during conventional steelmaking. These residual elements can significantly influence phase stability, defect formation, grain boundary segregation, and mechanical properties of steel products. The improved understanding of tramp element behavior is required to support future thermodynamic models and recycling strategies. Experimental investigations provide valuable information but often cannot directly reveal atomic-scale mechanisms governing tramp element interactions in iron-based alloys. The objective of this project is to employ Density Functional Theory (DFT) calculations to investigate the thermodynamic stability and defect interactions of selected tramp elements in body-centered cubic (BCC) iron. The study will focus on copper, tin, phosphorus, and antimony, which are among the most critical residual elements encountered in recycled steel streams. The calculations will determine solution energies, defect formation energies, vacancy interactions, and segregation tendencies. The generated atomistic data will provide fundamental insight into tramp element behavior and serve as input for future thermodynamic and kinetic modelling activities within MEDALS. The project will establish computational workflows for atomistic studies of recycled steels while generating scientifically valuable data for future larger-scale investigations.