Title:

Characterizing Defects and Disorder in Nuclear Materials with Neutron Total Scattering

Speaker:

Dr. Maik Lang

Affiliation:

University of Tennessee

When:

Thursday, September 10, 2020 at 11:15:00 AM   Add to Calendar

Where:

Room https://bluejeans.com/527719077

Host:

Dr. Chaitanya S Deo
cdeo3@gatech.edu

Abstract

Materials utilized in nuclear applications must safely operate within harsh environments characterized by intense radiation, high temperatures with steep gradients, and changes in chemistry. Prolonged exposure to these extremes will lead to material degradation that is ultimately driven by the formation of defects and disorder. To enhance the safety of current nuclear systems, and to enable next-generation nuclear technology, new classes of materials must be developed with superior structural stability and resistance. Key to these efforts is to fully understand the degradation mechanisms in current nuclear materials in terms of the underlying atomic scale defect structure. This presentation summarizes recent efforts to use stateof-the art analytical tools that have become recently available at large user facilities, such as the Spallation Neutron Source at Oak Ridge National Laboratory, to uniquely characterize nuclear materials. It will be shown that coupled X ray and neutron total scattering experiments can provide unique insights into the local defect structure of fuel type materials e.g., UO2 and wasteform ceramics e.g., A2B2O7 pyrochlore oxides. In almost all cases it was apparent that the formation of defects and disorder, and associated thermal recovery, is much more complex than previously though with distinct processes occurring over different length scales and sublattices in the material. This structural heterogeneity appears to be a general characteristic of disordered crystalline materials that is governed by a set of fundamental chemical rules.

Biography

Maik Lang is an Associate Professor and Pietro F. Pasqua Fellow in the Department of Nuclear Engineering at the University of Tennessee. He received his Ph.D. in physics from the University of Heidelberg Germany in 2004. He spent time as a postdoctoral researcher at the Helmholtz Center for Heavy Ion Research Darmstadt, Germany and at the University of Michigan Ann Arbor, USA. In August of 2013, he joined the Department of Nuclear Engineering at the University of Tennessee as an Assistant Professor. Dr. Lang performs research in the field of nuclear materials and investigates the behavior of materials under extreme environments, including energetic ion irradiation, high pressure and high temperature. He applies advanced materials characterization techniques that are available at user facilities, such as the Spallation Neutron Source at Oak Ridge National Laboratory. He is involved with several research projects funded by the U.S. Department of Energy.