PNNL scientists pioneer AI and atomic resolution microscopy of energy products

PNNL researcher Steven Spurgeon
PNNL researcher Steven Spurgeon’s research focuses on AI-driven approaches to the discovery and design materials for energy and computing technologies. Photo: Andrea Starr | Pacific Northwest National Laboratory
Research at the Department of Energy’s Pacific Northwest National Laboratory is forging new frontiers in learning how materials behave at the atomic scale. This knowledge is impacting the very future of energy, from the nuclear fuel cycle to quantum computing and the performance of electronics employed in spacecraft.
The work of PNNL staff scientist Steven Spurgeon encompasses many new challenges and initiatives in the field of energy. Recently, Spurgeon’s focus has been on understanding how spent nuclear fuel will degrade in a deep geologic repository environment, specifically the interaction of radioactive uranium dioxide (UO2) with the environment. UO2 is the primary fuel used in today’s commercial nuclear power reactors. Of concern is the oxidative tendency of UO2 in groundwater and the rate that the UO2 may degrade over time and release radioactive fission products from the spent fuel that would be disposed of.
“Being able to understand how materials evolve in high radiation environments, and being able to predict their lifetimes and how to dispose of them, is an important area of research for us,” Spurgeon says. “But it carries with it a lot of challenges.”
Scanning Transmission Electron Microscopy (STEM) is routinely used at the highest levels of research to see how the materials behave at the atomic level. PNNL has developed extensive expertise and capabilities to enable the study of radioactive materials like UO2.
“As you might imagine, you can't just pop highly radioactive materials into a microscope and expect to image them,” he said. “We have developed a whole infrastructure for that.” 
The Radiochemical Processing Laboratory, where PNNL’s JEOL Grand ARM STEM is located, is a Hazard Category II non-reactor nuclear research facility that uses hot cells to allow the research team to remotely extract tiny samples from larger crystals and fuel assemblies, and then bring them into the microscope. 
JEOL GrandARM STEM at PNNL’s Radiochemical Processing Laboratory
PNNL’s Radiochemical Processing Laboratory is home to a flagship JEOL GrandARM STEM used to examine materials in extreme radiation environments. Photo: Andrea Starr | Pacific Northwest National Laboratory
“Along with microscopy, PNNL has also developed extensive theory and data science to allow us to richly interpret what is happening,” says Spurgeon. PNNL is home to other world-leading experts in the actinides, such as Dr. Edgar Buck, and has collective expertise acquired over decades.
The team at PNNL, including Spurgeon and Buck, with collaborators at Lawrence Berkeley National Laboratory (LBNL) and the University of Chicago, developed the first-of-its-kind approach to map the chemistry of actinides (15 metallic radioactive elements including uranium) at the atomic level. They imaged pristine and decaying UO2 surfaces to discover the exact changes caused by air exposure in just the top few nanometers of the material.
Spurgeon, who has published more than 70 papers, reported the first atomic-resolution Electron Energy Loss Spectroscopy (EELS) mapping of any actinide in the Proceedings of the National Academy of Science. He explains that a major challenge is the complex dynamics of these elements. 
“Actinides are not stable. They are constantly losing protons and neutrons and are basically decomposing and changing, so the question is how do we even explore this?” Spurgeon says. “With the microscope we have, our unique facilities, and our institutional knowledge, we can do work no one else can do.”
Illustration of automated data acquisition and classification in the PNNL GrandARM STEM. Credit: Steven Spurgeon / Pacific Northwest National Laboratory
PNNL continually invests in state-of-the-art instrumentation. Among their multiple microscopes and analytical instruments are two JEOL atomic resolution Transmission Electron Microscopes: a JEOL JEM-ARM200F STEM that has served there for over a decade, and a JEM-ARM300F, or Grand ARM, STEM added four years ago and housed in the Radiochemical Processing Laboratory’s Radiological Microscopy Suite. PNNL researchers use the ARMs to examine microstructure, composition, and chemical states through multiple imaging and analytical modes, including energy-dispersive X-ray spectroscopy, electron energy loss spectroscopy, and 4D-STEM.
Spurgeon leads the way in using atomic resolution microscopy and Artificial Intelligence (AI) to harness the power of the volumes of data acquired in his work, as described in a recent perspective in Nature Materials. Starting in 2018, he and a team of researchers have made it a mission to leverage AI and data science to reshape experimentation in the microscopy field. He has worked closely with JEOL in AI applications and has been using the JEOL Python interface known as PyJEM that is enabling a new automated electron microscope platform. PNNL has also worked closely with JEOL/IDES, pioneers in the field of ultrafast and dynamic TEM
PNNL and JEOL/IDES recently signed a licensing and co-development agreement to commercialize the AI application. Together, they will bring to market the platform’s core concept—applying minimal, or “sparse,” data analytics to perform image classification, developed by the team in 2021. The new technologies developed under this partnership will be refined and made available to research organizations and private industry to accelerate scientific discovery with the TEM. 
Pushing the boundaries of microscopy work is mutually beneficial to PNNL and JEOL. “In reality, we should be building the microscope of five years from now,” says Spurgeon. “I’m excited to collaborate with JEOL on these emerging technologies—that's the future.” Part of Spurgeon’s mission at PNNL is to help create technologies that both push the boundaries of science and will “eventually get into the hands of industry, where they can have a broader impact.”
JEOL USA’s Vice President Thomas Isabell adds that Spurgeon’s research fuels the further development of JEOL’s microscopes, “It’s not just collaboration but co-development— that step beyond collaboration.” 
Spurgeon’s expertise reaches beyond his research at PNNL. In February 2022, he was appointed Affiliate Professor in the Department of Physics at the University of Washington. This will allow him to build new programs with UW that could help address key DOE challenges and will create professional opportunities for students. He also recently joined the editorial team of the international journal Microscopy and Microanalysis, the flagship publication of the Microscopy Society of America. 
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