Artificial Intelligence Reframes Nuclear Material Studies

Understanding why, where and when materials break down and show defects under extreme conditions over the course of their lifetimes is critical in order to judge a material’s suitability for use in a nuclear reactor. Extremely tiny defects are the first signs that a material will corrode, become brittle or fail. During experiments, defects happen within a picosecond, or one-trillionth of a second. At high temperatures, these defects appear and disappear in tens of milliseconds. Chen is an expert in IVEM experiments and said even he struggles to plot and interpret such fast-moving data.

The fleeting nature of defects during experiments explains why scientists traditionally captured only a smattering of data points along important lines of measure.

With Argonne funding, Chen has spent the past two years developing computer vision to track material changes from recorded experiments at IVEM. In one project, he examined 100 frames per second from videos one to two minutes long. In another, he extracted one frame per second in videos one to two hours long.

Similar to facial recognition software that can recognize and track people in surveillance footage, the computer vision at IVEM singles out material defects and structural voids. Instead of establishing a library of faces, Chen builds a vast, reliable collection of information about temperature resistance, irradiation resilience, microstructural defects and material lifetimes. This information can be plotted to inform better models and plan better experiments.

Chen stresses that saving time — a frequently cited benefit of computer-enabled work — isn’t the exclusive benefit of using AI and computer vision at IVEM. With a greater ability to understand and steer experiments that are underway, IVEM users can make on-the-spot adjustments to use their time at IVEM more efficiently and capture important information.

“Videos look very nice, and we can learn a lot from them, but too often they get shown one time at a conference and then are not used again,” said Chen. “With computer vision, we can actually learn a lot more about observed phenomena and we can convert video of phenomena into more useful data.”

DefectTrack Proves Itself Accurate and Reliable
In research published in Scientific Reports, Chen and co-authors from the University of Connecticut (UConn) presented DefectTrack, a MOT capable of extracting complicated defect data in real time as materials were irradiated.

In the study, DefectTrack tracked up to 4,378 different defect clusters in just one minute, with lifetimes ranging from 19.4 to 64 milliseconds. The findings were starkly superior to the same work by human counterparts.

“Our statistical evaluations showed that the DefectTrack is more accurate and faster than human experts in analyzing the defect lifetime distribution,” said UConn co-author and Ph.D. candidate Rajat Sainju.

Computer vision has multiple advantages; improved speed and accuracy are among them.

“We urgently need to speed up our understanding of nuclear materials degradation,” said Yuanyuan Zhu, the UConn assistant professor of materials science and engineer who led the university’s team of co-authors. “Dedicated computer vision models have the potential to revolutionize analysis and help us better understand the nature of nuclear radiation effects.”

Chen is optimistic that computer vision such as DefectTrack will improve nuclear reactor designs.

“Computer vision can provide information that, from a practical standpoint, was unavailable before,” said Chen. “It’s exciting that we now have access to so much more raw data of unprecedented statistical significance and consistency.”

Kristen Mally Dean is Communications Coordinator at Argonne National Laboratory