Advanced Characterization of Materials for Nuclear, Radiation, and Extreme Environments: Thermomechanical Testing and In Situ Environments
Sponsored by: TMS Nuclear Materials Committee
Program Organizers: Cody Dennett, Commonwealth Fusion Systems; Samuel Briggs, Oregon State University; Christopher Barr, Department Of Energy; Michael Short, Massachusetts Institute of Technology; Janelle Wharry, Purdue University; Cheng Sun, Clemson University; Caitlin Kohnert, Los Alamos National Laboratory; Emily Aradi, University of Manchester; Khalid Hattar, University of Tennessee Knoxville
Tuesday 2:00 PM
October 19, 2021
Room: A215
Location: Greater Columbus Convention Center
Session Chair: Charles Hirst, University of Michigan; Michael Short, Massachusetts Institute of Technology
2:00 PM Invited
Development of In-situ Atomic Scale Defect Spectroscopy during Ion Irradiation: Farida Selim1; A Jones1; Y Wang2; S Agarwal1; H Kim2; P Hosemann3; B Uberuaga2; 1Bowling Green State University; 2Los Alamos National Laboratory; 3university of California Berkeley
Development of in-situ positron capability such as in-situ TEM capability would provide a unique tool to monitor material response under extreme conditions. Positron is the only probe that detects atomic-size vacancies induced by irradiation with remarkable sensitivity and in-situ positron annihilation spectroscopy(PAS) can monitor formation of single vacancies and their evolution to voids revealing new radiation damage mechanisms. An in-situ positron beam during irradiation is being developed at the Ion Beam Materials Laboratory at the Los Alamos National Laboratory. Three beams are converging onto the target, an ion beam to create displacement damage and helium beam to simulate gas formation and positron beam to monitor in real time defect formation from individual cascades and their build up to large clusters and voids after cascade overlapping. In this talk I will describe the beam development, challenges, advantages, and limitations. Examples of PAS measurements will be presented to demonstrate the unique capabilities.
2:20 PM
In-situ Radiological Containment Sample Environments: A review of Capability and Compromises at X-ray and Neutron Sources: Travis Carver1; 1Los Alamos National Laboratory
While In-situ sample environments provide key temporal responses to external stimuli, they come with realizable costs and which may be significantly increased when radioactive samples are to be studied. A review of radioactive sample containment choices at as part of in-situ sample environments for X-ray and neutron scattering and imaging will be presented. From an experimental perspective, x-ray and neutron sources can provide up to bulk material properties responses, but the probing particle must penetrate each layer of containment twice. Sample size for neutron and x-ray experiments are often quite different, neutron samples are often an order of magnitude larger. Moreover, absorption by and parasitic scattering from the containment material can be very different for neutrons and x-rays. This presentation will review recent advancements of in-situ measurement environments for chemical kinetics, temperature, and loading of radioactive samples as well as present some examples of resulting data.
2:40 PM
Finding a Balance in FeCrAl Alloys: Utilizing Advanced Characterization, Testing, and Machine Learning to Balance Properties: Andrew Hoffman1; Vipul Gupta1; Daniel Ruscitto1; Bojun Feng1; Sayan Ghosh1; Raul Rebak1; 1GE Research
Due to their excellent performance in high temperature steam accident scenarios, FeCrAl alloys are being considered for commercial accident tolerant fuel cladding. Because FeCrAl alloys have traditionally been used for other high temperature applications (such as high temperature heating coils), understanding their behavior at lower temperatures and in light water reactor corrosion environments is paramount in accelerating the qualification of these materials. To elucidate a broader understanding of FeCrAl alloy behavior from a balanced perspective, GE Research is conducting experiments looking at the phase stability, corrosion behavior, and mechanical properties of FeCrAl alloys with varying compositions and microstructures. This experimental data is supplemented with CALPHAD modeling and probabilistic machine learning with intelligent experimental design to predict FeCrAl alloys optimized for performance and cost.
3:00 PM Invited
Revealing Hidden Defects via Stored Energy Measurements of Radiation Damage: Charles Hirst1; Fredric Granberg2; Penghui Cao3; Scott Middlemas4; R. Scott Kemp1; Ju Li1; Kai Nordlund2; Michael Short1; 1Massachusetts Institute of Technology; 2University of Helsinki; 3University of California, Irvine; 4Idaho National Laboratory
With full knowledge of a material’s structure, it is possible to predict any macroscopic property of interest. In practice, this is hindered by limitations of the characterization techniques used. Instead of spatial characterization, we propose to detect defects through their excess energy. We demonstrate this concept using experimental and simulated defect annealing of neutron-irradiated Ti. Differential scanning calorimetry (DSC) measurements reveal two energetically-distinct processes during stage V annealing, where the established recovery model predicts only one. Molecular dynamics (MD) simulations reveal the defects responsible, and show that the point defect-induced glide of dislocation loops contributes significantly to recovery. In comparison to prior literature, our experiments measure defect densities 4 times greater than those determined using transmission electron microscopy (TEM). Accurately characterizing these ‘hidden’ defects is crucial to understanding damage and annealing mechanisms at higher length scales, and will significantly advance the field of nuclear materials science.
3:20 PM Invited
Moduli Measurements of Fuels and Cladding Materials via Resonant Ultrasound Spectroscopy: Tarik Saleh1; Mathew Hayne1; Scarlett Widgeon Paisner1; Joshua White1; 1Los Alamos National Laboratory
Resonant Ultrasound Spectroscopy (RUS) is a powerful means of measuring the elastic modulus of materials very accurately. As such it is a useful tool for characterizing novel materials, measuring the changes in properties due to damage (radiation or otherwise), and as an initial measure of quality in small scale fabrication. This talk will cover RUS measurements on various fuel materials, concentrating on recent results on Uranium Nitride pellets along with some composite fuel materials. Cladding results will be presented, focusing on error analysis in moduli measurements in Zircalloy-4 cladding. Experimental equipment, environment, and challenges while measuring moduli on these materials will be highlighted. Other novel advanced reactor materials, such as metal hydrides and ferritic martensitic advanced reactor cladding materials, will be presented as well.
3:40 PM
In Situ Transient Grating Spectroscopy for Rapid Radiation Tolerance Characterization: Benjamin Dacus1; 1Massachusetts Institute of Technology
Void swelling and changes in thermal conductivity are life-limiting features of many nuclear reactor components. However, monitoring thermomechanical property evolution of materials in radiation environments has historically been a time consuming and expensive process. Transient grating spectroscopy (TGS) can break this bottleneck because of its ability to directly calculate thermal diffusivity and surface acoustic wave (SAW) speed from ion implanted regions in situ. In addition, recent results from the in situ ion irradiation TGS (I3TGS) system at Sandia’s Ion Beam Laboratory (IBL) have found a relationship between the onset of void swelling and a downturn in the SAW speed in FCC single crystals. We show that this method can be applied to a range of potential nuclear materials under the same irradiation and temperature conditions in order to rapidly draw conclusions about relative radiation tolerance by minimizing variation in thermoelastic properties as a surrogate for variation in mechanical properties.