Materials & Radiation Effects

The progress of any technology depends on the performance of the materials it employs.

Materials used in nuclear technology suffer from degradation due to radiation. The goal of the research on nuclear materials is to understand the effects of radiation and use the knowledge gained to improve materials resistance for applications in energy production or storage of radioactive materials.

The changes that occur in materials by radiation can also be exploited to develop materials with special properties that cannot be achieved by conventional methods of synthesis. This has opened up new areas of research involving the use of radiation effects and radiation-based techniques for materials synthesis and characterization. 

Faculty

Fei Gao

Professor

Gary Was

Professor Emeritus

Kevin Field

Associate Professor and Undergraduate Chair

Larry Aagesen

Adjunct Associate Professor

Lu-Min Wang

Professor and Graduate Chair

Michael Atzmon

Professor Emeritus

Peng Wang

Associate Research Scientist

Rebecca K. Lindsey

Assistant Professor

Stephen Raiman

Assistant Professor

Todd Allen

Chair and Professor

Yang Zhang

Professor and Engineering Physics Chair

Zhijie (George) Jiao

Research Scientist

Labs & Groups

Select Research Projects

Grand Challenge to Accelerated Deployment of Advanced Reactors—A Predictive Pathway for Rapid Qualification of Core Structural Materials​
Lead: Prof. Gary Was
This DOE NEUP Integrated Research Project will provide a predictive tool incorporating ion irradiation and computational materials modeling to determine the microstructure and mechanical properties of core structural materials, benchmarked against reactor data and codified in ASTM standards, to provide licensees with a justification of core material performance in their safety case for the NRC, and thus, accelerating the deployment of advanced reactor designs critical to achieving the U.S. clean energy climate change goals.

Mechanism-Driven Evaluations of Sequential and Simultaneous Irradiation-Creep-Fatigue Testing
Lead: Prof. Kevin Field
This DOE Research and Development Project addresses a critical need for irradiation and creep-fatigue testing by carrying out a systematic, mechanistic-driven benchmarking for irradiation creep, irradiation fatigue and creep-fatigue tests under various environments.

Deformation and Structural Transformations in Metallic Glasses
Lead: Prof. Michael Atzmon
Metallic glasses are metal alloys that do not exhibit crystalline order. They have high strength and can store large amounts of elastic energy. However, their plastic deformation is localized to nanometer-sized shear bands, making them macroscopically brittle. A challenge to practical applications of metallic glasses is to prevent their catastrophic failure along shear bands. Using a combination of experiment and modeling, we characterize defects in metallic glasses and their dependence on thermomechanical treatment. The resulting insights into deformation mechanisms are expected to contribute to future alloy design for structural applications.

Radiation-Induced Amorphization in Ceramics and Minerals
Lead: Lu-Min Wang
This program addresses fundamental issues in particle-solid interactions for structurally and compositionally complex ceramics. The effects of structural topology, bond type, dose rate, and irradiation temperature on the final state of the irradiated material are investigated. This work is led by Lu-Min Wang.

Irradiation-Assisted Stress Corrosion Cracking of Austenitic Stainless Steels
Lead: Prof. Gary Was
This program is investigating the influence of irradiation on the stress corrosion cracking process in stainless steels used in nuclear reactor cores. High energy protons are used in place of neutrons to induce grain boundary segregation and microstructural changes, eliminating the problem of sample activation and reducing sample analysis time from years to months. 

Materials for the Very High-Temperature Gas Reactor
Lead: Prof. Gary Was
This experimental program addresses two of the materials challenges of the very high-temperature gas reactor (VHTR). They are the oxidation of metallic components at temperatures up to 1000°C and the irradiation-induced creep that will occur in the TRISO fuel particles. Understanding these phenomena is critical to the development of materials that can operate in very high-temperature environments. 

Behavior of Irradiated Materials in Supercritical Water
Lead: Prof. Gary Was
This program is focused on the behavior of materials in supercritical water, relevant to the supercritical water reactor. However, little is known about the behavior of materials in both the unirradiated and irradiated conditions. Materials irradiated with accelerator-produced ions and in reactor cores are studied and facilities to test neutron-irradiated materials have been built for that purpose.

Development of High-Performance ODS Alloys
Lead: Prof. Fei Gao
The research employs coordinated experiments to study swelling, radiation hardening, and changes in mechanical properties not only of these ODS alloys but also further-optimized ODS candidates resulting from these first-round studies. The project will identify key factors influencing the radiation tolerance of new ODS alloys for further property optimization. To gain atomic-scale understanding, the research integrates these experiments with modeling capabilities, including molecular dynamics and dislocation dynamics simulations to understand the roles of yttria and other dispersoids as well as their various dispersion modes on both microstructural changes and mechanical property changes.

Fission Product Transport in TRISO Fuel
Lead: Prof. Fei Gao
We combined experiments and computer simulation to study the diffusion and release of fission products (FPs) for thermal and irradiation conditions, as well as synergistic effects of radiation damage and fission products at IPyC/SiC interface and in SiC. In particular, the efforts will focus on understanding both thermal and irradiation-enhanced diffusion of Ag, I, Pd, and Ru in the bulk and along grain boundaries in SiC. The goal of this research is to develop a comprehensive atomic-level understanding of the dynamics of FPs and provide physics-based diffusion kinetics to further improve empirical models used in the PARFUME code at Idaho National Laboratory (INL), which will be benchmarked against data obtained from INL’s Advanced Gas Reactor (AGR) Fuel Development and Qualification Program.

Atomic- and Meso-scale Computational Simulation for Developing Multi-Timescale Theory for Radiation Degradation in Electronic and Optoelectronic Devices
Lead: Prof. Fei Gao
This project has been supported by the Air Force Research Laboratory to study radiation degradation in electronic and optoelectronic devices through atomistic- and mesoscale computational simulations, thus developing a multi-time scale theory. The research is to simulate atomistic- and mesoscale behavior of defect evolutions in compound semiconductors, including ultrafast displacement cascades, intermediate defect stabilization, and cluster formation, as well as slow defect reaction and migration. The fundamental mechanisms and knowledge gained from atomic- and mesoscale simulations will be input into rate-diffusion theory as initial conditions to calculate the steady-state distribution of point defects in a mesoscopic layered-structured system, thus allowing the development of a multi-timescale theory to study radiation degradation in electronic and optoelectronic devices.

Defect Detection Using Deep Learning
Lead: Prof. Kevin Field
Electron microscopy is widely used to explore defects in crystal structures, but human tracking of defects can be time-consuming, error-prone, and unreliable, and it is not scalable to large numbers of images or real-time analysis. In this work, we explore the application of machine learning approaches to find the location and geometry of different defect clusters in electron microscopy images of irradiated steels. We show that performance comparable to human analysis can be achieved with relatively small training data sets. We explore multiple deep learning methods that provide various features, e.g., fast processing for video and pixel-level categorization to simplify defect dimension determination.

Radiation Effects in Additive Manufactured Steels
Lead: Prof. Kevin Field
Ferritic martensitic (FM) steels are candidate materials for high-dose applications in advanced nuclear reactor power applications due to their low swelling rates. FM steels are known to degrade in these high-dose applications due to irradiation hardening, helium embrittlement, and swelling. The use of additive manufacturing, including directed energy deposition (DED) techniques, is gaining increasing acceptance for consideration in the production of commercial nuclear reactor components. However, parallels with, or tangent to, the commonly identified degradation modes in FM steels have yet to be demonstrated for DED material. In this project, we study the radiation effects of HT-9 produced using powder-blown laser DED at Oak Ridge National Laboratory’s Manufacturing Demonstration Facility (MDF) and then irradiated at the Michigan Ion Beam Laboratory (MIBL).