The U.S. Department of Energy (DOE) has designated South Korea as a “Sensitive and Other Designated Country” (SCL), a list historically reserved for sanctioned nations or those deemed security risks.
The list, which included 25 countries as of 2024, grew to 26 with the addition of South Korea earlier this year. Seoul is now the only U.S. treaty ally to receive this classification, as Israel—also on the list—lacks a formal security pact with Washington.
The DOE compiles the list based on factors such as national security risks, nuclear nonproliferation concerns, economic security threats, and regional instability. The CIA and the Department of Defense are also known to be involved in monitoring these classifications.
As of 2024, the list included China, Taiwan, Russia, Iran, North Korea, India, Ukraine, Iraq, Syria, Israel, and Cuba, among others. Notably, it did not include close U.S. partners such as Japan, Australia, New Zealand, or any NATO members.
The classification is expected to impact U.S.-South Korea cooperation in nuclear energy, nonproliferation efforts, and advanced technology sectors such as semiconductors, artificial intelligence, quantum computing, and biotechnology.
Experts say nuclear energy collaboration could be most affected. Washington has already imposed export controls on South Korean nuclear technology, and the new classification could further complicate joint research and development (R&D).
At the beginning of this year, the South Korean and U.S. governments signed a memorandum of understanding (MOU) on nuclear export and cooperation, while Korea Hydro & Nuclear Power (KHNP) and Westinghouse Electric Company entered into a commercial agreement. The deals were aimed at strengthening partnerships on projects such as the Czech Republic’s planned nuclear plant.
However, analysts warn that cooperation on next-generation nuclear technologies, including small modular reactors (SMRs) and spent fuel reprocessing, could face U.S. restrictions. “South Korean researchers may experience delays in obtaining approvals to visit U.S. facilities, and importing key research equipment could become more difficult,” said Moon Joo-hyun, a professor at Dankook University.
There are also concerns that Washington may distance itself from Seoul on spent nuclear fuel reprocessing. From 2011 to 2020, the two countries jointly researched pyroprocessing and sodium-cooled fast reactors (SFRs), but progress has stalled. “The delayed start of the second phase of the research has led to speculation that the U.S. is intentionally limiting South Korea’s access to nuclear technology,” said Jeong Dong-wook, a professor at Chung-Ang University.
Several South Korean government research institutes currently collaborate with DOE-affiliated laboratories. The Korea Institute of Science and Technology (KIST) has worked with Lawrence Livermore National Laboratory (LLNL) since 2019 on renewable energy and computational science, while joint battery research is underway with Argonne National Laboratory and Brookhaven National Laboratory.
The Korea Research Institute of Bioscience and Biotechnology (KRIBB) is engaged in biotech research with Lawrence Berkeley National Laboratory, and the Korea Electronics and Telecommunications Research Institute (ETRI) signed an MOU with Argonne in January to collaborate on next-generation semiconductor technologies.
Concerns over the SCL classification surfaced after U.S. research institutions reportedly inquired whether South Korean partners were aware of the change and whether it could affect ongoing collaborations. “Given that U.S. researchers are already raising these questions, existing projects could face new hurdles,” said a South Korean research official.
The classification takes effect on April 15. While the South Korean government is in talks with the U.S. to address concerns, experts say reversing the decision before it is implemented will be difficult.
“So far, there have been no significant changes to bilateral cooperation,” said Chae Young Lim, senior vice president for nuclear policy and strategy at the Korea Atomic Energy Research Institute. “But we need to monitor the situation closely.”
