Nuclear Engineering & Engineering Physics Research
Nuclear and Fusion Materials
Nuclear reactors and fusion power plants offer some of the most extreme environments for materials to survive, with a unique combination of high temperatures, high stress, corrosive fluids, and intense radiation fields. In this research area, we study how materials respond to these environments in order to identify materials or material modifications that perform as required in their engineered systems. Experimental facilities, both small and large, simulate these environments in different ways where material samples can be exposed, and then characterized with a wide array of microscopes and probes. Computational researchers develop new ways to predict material behavior, informed by the results of these experiments and aid the development of new materials and new ways to manufacture those materials.
Faculty
Centers, consortia and institutes
Nuclear materials
The neutrons and charged particles inevitably present in nuclear facilities can do significant damage to structural materials. Atoms are displaced, structures are deformed, and properties are modified consequently. We must understand these phenomena in order to produce viable reactor designs and understand component lifetime issues. Professors Sridharan, Couet, Zhang, Hirst, Szlufarska and Morgan have state-of-the-art experimental and computational research programs to study the physics of these radiation damage events and the subsequent effect on reactor design, with the objective to design fuels and structural materials that can improve the economics and safety of current nuclear reactors and also withstand the irradiation damage in advanced nuclear reactors.
Irradiation effect studies
Materials used in nuclear reactors are subject to intense neutron irradiation, which damage materials and degrade their mechanical integrity and functional properties, affecting reactor safety and economics. Understanding irradiation effects in nuclear fuels and materials is critical for mitigating materials degradation in current nuclear reactors and for developing novel fuels and materials in advanced reactors. Synergistic modeling and experimental studies are carried out in Professors Couet, Sridharan, Hirst, and Zhang’s groups to investigate how irradiation by high-energy particles changes material microstructure and properties. On the modeling side, Professor Zhang’s group focuses on atomic scale studies of the fundamental properties of lattice defects and atomistically informed mesoscale modeling of irradiation-induced damage evolution, defect self-organization, element segregation, and precipitation. The modeling studies are strongly coupled with experimental studies led by Professors Couet and Sridharan. Using ion beam irradiation at the Wisconsin Ion Beam Laboratory, a Nuclear Science User Facility, Couet and Sridharan study the irradiation effects in materials using high-energy light and heavy ions, which are used to mimic neutron irradiation effects. The coupled modeling and experimental capabilities provide a powerful toolkit for understanding irradiation effects, for the purpose of guiding materials design for use in advanced nuclear reactors. Hirst will be leading the development of several in situ irradiation experiments, including both mechanical testing and differential scanning calorimetry, to explore a wide variety of loading (tensile/creep/fatigue) and annealing (cryogenic to high temperature) scenarios at the Ion Beam Laboratory.
Corrosion studies
As we look to the future, reactors will tend to operate at higher temperatures in order to increase the efficiency of the energy conversion processes or to produce process heat for industrial applications such as hydrogen production. This leads us to the use of new coolants, such as molten salts, liquid metals and high-temperature gas, and new materials and the need for ensuring that these combinations are compatible. Professors Sridharan, Anderson, and Couet all operate a variety of experiments that test the compatibility of coolants such as high temperature pressurized water, molten salt (fluorides and chlorides), lead, and liquid metals (sodium and lead) with innovative, high-temperature structural materials. The experimental studies are complemented by atomistic and mesoscale modeling of corrosion in Professor Zhang’s group.