Woodruff School of Mechanical Engineering
Nuclear & Radiological Engineering and Medical Physics Programs
Laser Surface Acoustic Wave (LSAW) Quantification of Radiation Damage in Structural Materials
Prof. Michael Short
Massachusetts Institute of Technology
Friday, April 17, 2015 at 11:00:00 AM
Boggs Building, Room 3-47
Dr. Anna Erickson
The largest technical challenges to the successful deployment of advanced nuclear energy systems depend strongly on nuclear material performance. Due to the limited ability to collect data at realistic operating conditions of temperature, pressure, corrosive environment, and radiation dose rate, our understanding of long-term (>50 years) nuclear material performance is currently insufficient to confidently license and operate advanced nuclear energy systems. The application of mesoscale science, which bridges the length and time scales from the atomistic unit process towards the engineering scale, promises to fill key gaps in material performance data and fundamental understanding of radiation effects in structural materials. In particular, the accurate, in-situ collection of measurable radiation damage, not simply calculating the imparted dose, promises to reinvent the way in which nuclear materials science is conducted. We propose the application of laser surface acoustic wave (LSAW) analysis as a new way to correlate applied radiation dose to actual resultant radiation damage as a function of experimental/operating conditions. In particular, a deterministic correlation between changes LSAW signal components (acoustic frequency space, thermal diffusivity, elastic moduli, surface Rayleigh wave dampening) and applied dose at key conditions (temperature, pressure, material, incident radiation type & energy, dose rate) has the potential to reduce or eliminate costly post-irradiation examination (PIE) and repetitive ion irradiation studies. For example, installing an LSAW-equipped beamline on a heavy ion accelerator would allow the in-situ collection of damage vs. dose data, eliminating variability between samples and greatly refining the quality and frequency of collected data. Ultimately the goal of this work is to establish a new fundamental unit of radiation damage, by deconvolving LSAW signal changes to the onset and growth of specific modes of radiation damage (void swelling, defect clustering, dislocation network formation). This new unit will complement the DPA as a way to measure radiation damage, prompting the reinterpretation of past DPA-based datasets into this new unit.
Prof. Michael Short joined the faculty in the Department of Nuclear Science and Engineering in July, 2013. He brings 12 years of research experience in the field of nuclear materials, microstructural characterization, and alloy development. In particular, he has worked on the development of bi-metal composites to improve the corrosion resistance and economics of the lead-bismuth eutectic fast reactor. His research is a mixture of large-scale experiments, micro/nanoscale characterization, and multiphysics modeling & simulation. Main areas of Prof. Short's research are focused on 1) Mesoscale, non-contact quantification of radiation damage, 2) Fundamental understanding and prevention of deposition and adhesion of deleterious phases, such as CRUD in nuclear reactors, as fouling deposits in energy systems, 3) Changes in material properties subject to irradiation by neutrons and/or ions, in particular, metals, welds, and joints, and 4) New nuclear material development, including CRUD-resistant surface modifications, multimetallic layered composites, and new nuclear structural materials.
Group Website: http://web.mit.edu/shortlab/