As the demand for nuclear energy increases, there are growing challenges for managing the spent nuclear fuel. The United States doesn’t yet have a licensed site for permanent storage, so the spent fuel is stored in canisters at multiple interim sites around the country.
However, monitoring the spent fuel in those sealed canisters is challenging because they’re specifically designed to shield radiation from the nuclear material inside. That means traditional imaging technologies that use X rays or gamma rays won’t work. Opening the canisters for inspection puts workers at risk for radiation exposure.
“It’s very important to manage this spent nuclear fuel, and we really need a licensed and certified technology for safely and securely monitoring it. That technology is something I’m working on in my research,” says JungHyun Bae, who is joining the UW-Madison Department of Nuclear Engineering and Engineering Physics as an assistant professor in January 2026.
Bae’s research focuses on developing muon detectors, which allow scientists to peer deep inside matter without damaging samples. His research could significantly enhance the ability to monitor and safeguard nuclear materials. It also promises to help address a critical challenge for quantum computing.
Muons are fundamental subatomic particles produced when cosmic rays hit the Earth’s atmosphere. These particles, which travel at nearly the speed of light, constantly hit every inch of the Earth’s surface and pass through almost any substance, penetrating far below the surface of the Earth. Bae’s muon detector analyzes how muons scatter and lose energy when passing through matter. The system provides detailed images of objects, such as the contents of shielded nuclear fuel canisters.
Bae comes to UW-Madison from Oak Ridge National Lab, where he is the Eugene P. Wigner Distinguished Staff Fellow leading projects for muon tomography. At ORNL, Bae and his colleagues developed a mobile muon detector with dramatically improved image quality compared to other muon tomography systems. Bae developed the concept for this detector during his doctoral research, which focused on complex computational simulations to validate muon tomography applications.
Bae earned his bachelor’s degree in nuclear and quantum engineering from the Korea Advanced Institute of Science and Technology and his master’s degree in nuclear engineering from the University of California, Berkeley. He earned his PhD in nuclear engineering from Purdue University in 2022.
At ORNL, he has also been leading a project aimed at enhancing national security. Radiation portal monitors are large radiation detectors installed at seaports, airports and other sensitive facilities to scan cargo, vehicles and passengers for hidden nuclear materials. However, muons can interfere with the radiation detector, causing false alarms. Bae and his collaborators developed a cosmic radiation noise cancellation algorithm that essentially removes or minimizes the muon signals. “This algorithm significantly improves the detection sensitivity and accuracy of radiation portal monitors, which saves time and money and increases security,” he says.
In addition to nuclear applications, Bae is tackling a critical challenge for quantum computing. Qubits, the fundamental building blocks of quantum computers, are highly sensitive and prone to errors caused by cosmic ray muons. Such errors can easily break down the operation of a quantum computer. To address this problem, Bae is using his muon detector to study how muons interact with qubits. With these insights, he aims to develop new error correction methods and inform the design of more resilient quantum hardware.
“Using my muon detector and methods, I believe I can make a very significant contribution to society by helping to enable practical quantum computers,” Bae says. “UW-Madison has many outstanding researchers in the quantum computing and quantum engineering areas, and that attracted me to the university. I’m so excited to collaborate with them.”
Photo of JungHyun Bae by Joel Hallberg