NRE 8011/8012 Seminar


Scaling Analysis in Nuclear Material Studies


Dr. Tianyi Chen


Assist Professor at Oregan State University


Thursday, April 18, 2024 at 11:00:00 AM   


Virtual Building


Dr. Fan Zhang


Nuclear material experiments are often conducted using accelerated testing on reduced-sized specimens. An extreme example of this is nanomechanical testing of ion-irradiated specimens, where the deformation zone is significantly smaller and the displacement damage rate much higher compared to typical service conditions. These differences, known as spatial and temporal scaling between the testing and prototypical conditions, result in phenomenological dissimilarities by distorting the rate-controlling physical processes. By dynamically analyzing these distortions as they evolve throughout the accelerated testing period, it becomes possible to identify and quantify the underlying material parameters. This approach provides a pathway to leverage lower-cost and faster-turnaround experiments for model verification, improvement, and parameterization, and, as a result, establishes a connection between such experiments and performance prediction as well as material qualification. During this talk, we will present an example focused on the radiation responses of additively manufactured (AM) stainless steels (SSs). We will demonstrate that the combination of high dose rate of ion irradiation and high dislocation densities of AM SSs exacerbates vacancy accumulation, leading to more severe void swelling compared to conventional SSs. Interestingly, a rate-theory model parameterized with the aid of scaling analysis predicts a reversal in the swelling severity of AM SSs compared to their conventional counterparts. This prediction, supported by existing literature, highlights the significance of scaling analysis in extracting knowledge from accelerated testing. Furthermore, we will discuss our ongoing efforts to apply scaling analysis in the studies of nuclear fuels and mechanical properties.


Dr. Tianyi Chen is an assistant professor of Nuclear Science and Engineering at Oregon State University. His research spans the fields of radiation, materials, and mechanics, focusing on the fundamental understanding of radiation effects, radiation damage and property degradation of nuclear materials, as well as accelerated testing and advanced characterizations. Dr. Chen employs a combination of experimental and computational tools to address engineering and scientific challenges related to nuclear-relevant materials. Prior to joining Oregon State University, Dr. Chen served as a post-doctoral research associate at Oak Ridge National Lab from 2016 to 2018. He completed his Ph.D. in nuclear science and engineering at Texas A&M University from 2010 to 2015, during which he also worked at Idaho National Laboratory and Argonne National Laboratory. Dr. Chen earned his bachelor's degree in Physics from Peking University in 2010. Join Zoom Meeting Meeting ID: 954 5592 3553 Passcode: 428671


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