Atoms, Alloys, and Aging: Engineering Safer Nuclear Systems

Presented by Julie Tucker, Professor of Materials Science and Academic Director of Design for Social Impact 

Nuclear power plants generate approximately 16% of the United States' electricity and play a critical role in delivering low-carbon energy. A key challenge in meeting growing energy demands is understanding the long-term behavior of structural materials as plant lifetimes are extended from 40 to 60 years and beyond. Nickel-chromium-based alloys are widely used for their corrosion resistance and mechanical stability at high temperatures. However, these alloys can undergo phase transformations during long-term thermal aging or irradiation, leading to the formation of brittle intermetallic phases. This transformation is associated with reduced ductility and increased brittleness, raising concerns about component reliability. Studying this transformation is challenging because it may take several decades to occur under normal operating conditions. In this work, we accelerate the transformation using irradiation and elevated temperature testing. We also employ atomistic simulations – computational methods that model the behavior of materials at the atomic level – to understand the mechanisms behind phase formation. Together, these approaches enable us to build predictive models of how mechanical properties evolve over time and provide guidance to the industry on component lifetimes. 

About Tucker:
Tucker earned her B.S. in Nuclear Engineering from the University of Missouri–Rolla. She attended graduate school at the University of Wisconsin–Madison as a Naval Nuclear Propulsion Fellow, where she received her M.S. and Ph.D. in Nuclear Engineering with a minor in Materials Science in 2008. After graduation, Tucker spent five years as a Principal Scientist at Knolls Atomic Power Laboratory in Schenectady, NY researching welding and the thermal stability of structural alloys for nuclear power systems. She joined the School of Mechanical, Industrial, and Manufacturing Engineering at Oregon State University as an Assistant Professor in 2013 and was promoted to Associate Professor in 2019 and Full Professor in 2023. From 2019 to 2024, Tucker served as the Materials Science Interdisciplinary Graduate Program Director. In 2024, she was appointed the Academic Director for the Design for Social Impact Program.  Tucker has an active research group focused on degradation of materials in extreme environments and alloy development. Her research efforts leverage both modeling and experimental approaches to gain fundamental understanding of materials performance.