ORNL’s nuclear materials research is foundational in establishing safety margins for current and advanced reactors. When we test a material under extreme conditions, we are seeking to understand why a material failed as well as the combination of factors and physical processes leading to that failure, and how to fabricate more resilient materials.
My focus is on how radiation interacts with materials—specifically, how we can design test conditions to determine changes to physical processes during irradiation. We test materials for tensile strength and creep performance and then correlate the macroscopic behavior of a material to its microstructure by examining small slices with electron microscopy and other techniques. From the examinations and performance, I infer what combination of processes led to the observations and use physics-based models to explain the results. These insights can lead to more-predictive models to help inform the limits of a material and determine a safe window for operation.
Right now, radiation damage experiments to measure end-of-life expectations can take years to perform in test facilities—assuming space is available. Understanding the importance of this data and limited sample availability, I am researching new techniques for small-scale materials testing to reduce the amount of material needed to assess performance. Lab-scale experiments using ion beams to accelerate irradiation evaluations are rapidly progressing, providing more testing capabilities to advance materials qualification and bring more nuclear energy on line.
Nuclear science has a legacy of breaking boundaries and driving progress forward. Testing the limits of nuclear materials helps us ensure nuclear energy powers our lives safely and reliably for decades.
Stephen Taller (tallersa@ornl.gov) is an R&D associate staff scientist in the Fuel Cladding and Core Internals Group at Oak Ridge National Laboratory.
