Advanced Characterization of Materials for Nuclear, Radiation, and Extreme Environments III: Beamline/Scattering
Sponsored by: TMS Nanomechanical Materials Behavior Committee, TMS Nuclear Materials Committee
Program Organizers: Cody Dennett, Commonwealth Fusion Systems; Samuel Briggs, Oregon State University; Christopher Barr, Naval Nuclear Laboratory; Michael Short, Massachusetts Institute of Technology; Janelle Wharry, Purdue University; Cheng Sun, Clemson University; Caitlin Kohnert, Los Alamos National Laboratory; Khalid Hattar, University of Tennessee Knoxville; Yuanyuan Zhu, University Of Connecticut
Monday 2:00 PM
October 10, 2022
Room: 329
Location: David L. Lawrence Convention Center
Session Chair: Caitlin Taylor, Los Alamos National Laboratory; Khalid Hattar, Sandia National Laboratories
2:00 PM Invited
Advanced Synchrotron Characterization of Fission and Fusion Energy Materials: David Sprouster1; T Koyanagi2; B Cheng1; D Bhardwaj1; J Gentile1; J Trelewicz1; L Snead1; 1Stony Brook University; 2Oak Ridge National Laboratory
In the present work, we describe our recent efforts employing advanced non-destructive synchrotron based characterization efforts to support the fabrication, and post-irradiation examination of materials for advanced fission and fusion energy systems. When coupled with electron microscopy, and other conventional methods, synchrotron based characterization techniques provide complimentary quantitative insights across multiple length scales needed to fill critical knowledge gaps and predict long-term behavior and performance. Specific material systems planned for discussion here will include advanced ceramic composites for next-generation fission reactors, and the multi-modal characterization of transmutation products in fusion structural materials. Finally, we highlight new and future opportunities in leveraging synchrotron-based techniques to address fundamental and applied materials science challenges to aid in developing a detailed physical understanding of radiation-induced microstructures in materials for advanced nuclear energy applications.
2:30 PM Invited
Neutron Imaging at LANSCE: Characterizing Materials for the Next Generation of Nuclear Reactor Designs: Alexander Long1; Sven Vogel1; Marisa Monreal1; J. Jackson1; S. Parker1; Holly Trellue1; Erik Luther1; Aditya Shivprasad1; Thilo Balke1; James Torres1; 1Los Alamos National Laboratory
Neutrons are an ideal probe for characterizing nuclear fuels and moderator materials for next generation nuclear reactors as their interactions with matter create complex attenuations that result in a unique combination of isotopic specific contrast mechanisms and penetrabilities, thus making neutrons well suited for investigating both high-z materials (actinides in nuclear fuels) and low-z materials (metal hydrides). Furthermore, the high material penetrability with neutron imaging allows for in-situ measurements at extreme conditions (high temperatures or activity) where bulky sample environments are required. Presented work will include the ongoing efforts at the Los Alamos Neutron Science Center (LANSCE) to develop advanced neutron imaging capabilities on Flight Path 5 (FP5) specifically for characterizing materials for advanced reactor designs. These efforts range from thermophysical property measurements of chloride-based molten salt-, to hydrogen characterization in metal hydrides moderator materials, to post-irradiation examination with energy resolved neutron imaging of actinides in fresh and irradiated fuels.
3:00 PM
Probing Short-Range Order in Disordered Crystalline Materials for Extreme Environments
: Eric O'Quinn1; Devon Drey1; William Cureton2; Gianguido Baldinozzi3; Maik Lang1; 1University of Tennessee; 2Oak Ridge National Laboratory; 3Université Paris-Saclay
Structurally disordered crystalline materials are used in a variety of energy technologies from solid oxide fuel cells to nuclear fuels and waste forms. Here, we present selected examples of synergistic experimental and modeling approaches that reveal short-range order in oxide materials that appear disordered over longer length scales. Our research strategy focuses on state-of-the-art neutron total scattering experiments with the world’s most intense pulsed neutron beam, the Spallation Neutron Source (ONRL); neutrons scatter intensely from oxygen permitting analysis of anion sublattice behavior and total scattering yields pair distribution function (short-range) data. Results are presented for total scattering experiments with combined first principles and Reverse Monte Carlo modeling that revealed the short-range oxygen clustering in the nuclear fuel UO2+x. Another example illustrates the analysis of unexpected short-range order in disordered AB2O4 spinel and disordered A2B2O7 pyrochlore oxides, proposed for use in lithium battery applications, actinide transmutation matrices, and nuclear waste forms.
3:20 PM Invited
Three-dimensional Characterization of Multiple Phase Regions within a Neutron Irradiated U-Zr Fuel: Maria Okuniewski1; Nicole Rodríguez Pérez1; Alejandro Figueroa Bengoa1; Kezia Peck1; Jonova Thomas2; 1Purdue University; 2Argonne National Laboratory
Uranium-zirconium (U-Zr) alloys are candidate fuels for fast-spectrum advanced reactors that are currently under development by government and private industry. Uranium-zirconium fuels exhibit a number of favorable attributes including ease of fabrication and recycling, high thermal conductivity, high heavy metal density, and favorable response during off-normal events. During neutron irradiation U-Zr fuels are subjected to constituent redistribution of the major elements, resulting in multiple concentric redistribution regions that exist within differing radii of the fuel cross-section. These regions are complex in nature and contain multiple crystallographic phases that accommodate fission gas bubbles and solid fission products differently. This research explores two different advanced three-dimensional characterization techniques, synchrotron micro-computed tomography and focused ion beam-scanning electron microscopy serial sectioning, to examine a U-10wt.%Zr fuel irradiated in the Fast Flux Test Facility to 5.7 at.% burn-up. Additionally, newly developed segmentation techniques and computer vision are applied to interpret the complex microstructures.
3:50 PM Break
4:10 PM
Hydrogen Dynamics in Yttrium Hydride Moderator Material: James Torres1; Alexander Long1; Dale Carver1; Sven Vogel1; Aditya Shivprasad1; Tyler Smith1; Caitlin Taylor1; Erik Luther1; Holly Trellue1; 1Los Alamos National Laboratory
A compact, nuclear microreactor that utilizes low-enriched uranium fuel is a promising solution to meet US energy demands for remote (e.g., space) and highly dense population areas. Yttrium hydride (YH) is the candidate moderator material for the microreactor design, chosen based on its superior retention of hydrogen at high temperatures. To date, there is a dearth of knowledge on hydrogen diffusion properties in YH. Hydrogen-mapping capabilities via neutron imaging are currently under development at the Los Alamos Neutron Science Center (LANSCE) with the goal to characterize hydrogen diffusion in YH samples as a function of stoichiometry, temperature, and phase fraction at both ambient and extreme environments (temperature gradients). Herein, we share our recent progress in technique development and include initial results from concentration- and temperature-gradient measurements from LANSCE. Additional measurements planned for Q4 of FY22 may also be discussed.
4:30 PM Invited
Elucidating Helium Induced Softening in Nanograin Tungsten Through Electron Microscopy Informed Synchrotron X-Ray Scattering: W. Cunningham1; Cormac Killeen1; Yang Zhang1; David Sprouster1; Osman El Atwani2; Jason Trelewicz1; 1Stony Brook University; 2Los Alamos National Laboratory
Relative to coarse-grained tungsten where helium bubbles promote classical irradiation hardening, ultrafine-grained tungsten experiences biased helium bubble formation at grain boundaries and reported softening. Here, we examine the influence of the helium cavity distribution on the mechanical behavior of fine-grained tungsten using targeted implantation studies. Hardness and modulus are mapped as a function of irradiation temperature and fluence in two different tungsten microstructures via nanoindentation. Scaling behavior is explained based on the helium cavity microstructure, which is characterized through transmission electron microscopy informed synchrotron x-ray scattering experiments. We show that at the lowest fluence, the formation of grain boundary cavities is correlated to a reduction in hardness, which is recovered with increasing fluence due to cavity induced hardening. Insights from molecular dynamic simulations demonstrate that the observed softening can be attributed to enhanced strain accommodation within the helium loaded grain boundaries.