Worked on the terrapower/armi repository to address a critical issue in material density calculations by delivering a targeted bug fix. Refactored the component construction and density setting logic to ensure that custom isotopic densities are accurately applied, particularly when interacting with other material properties such as TD_frac. This approach prevents overspecification and maintains the integrity of material properties within simulation workflows. Leveraged expertise in Python, material science, and reactor physics to improve the reliability of density-dependent results. The work focused on enhancing simulation accuracy by ensuring that custom isotopic definitions consistently influence material density calculations across various use cases.