On Tuesday (March 18), Joseph Yun, the Chargé d'Affaires ad interim of the US Embassy in South Korea, stated that South Korea had been added to the US Department of Energy's watch list due to improper handling of sensitive information by South Korean personnel visiting US laboratories.

Yin Rushang [Joseph Yun] said at the American Chamber of Commerce in South Korea that this measure is limited to facilities of the US Department of Energy and has no broader impact on the cooperation between the two allies, the US and South Korea.

The US Department of Energy confirmed this week that it had classified South Korea as a "sensitive" country in January, but did not provide an explanation for the decision.

Yin Rushang did not offer a detailed explanation on Tuesday but noted that more than 2,000 South Korean students, researchers, and government officials visited US laboratories last year. He said, "It’s not a big issue; something happened because a lot of Koreans went there."

US Department of Energy Contractor Attempted to Bring Nuclear Reactor Design Software to South Korea
The US Department of Energy stated in a report last year that it had terminated a contractor who attempted to board a flight to South Korea with "proprietary nuclear reactor design software" owned by Idaho National Laboratory.

The report indicated that this individual had been in contact with a foreign government, though it did not specify which country. US law enforcement agencies are currently investigating this individual.

It remains unclear whether this case contributed to the US Department of Energy’s decision, and neither the Department of Energy nor the State Department immediately commented on the matter.

A spokesperson for the US Department of Energy stated that the decision to place South Korea on the watch list was made by the administration of former President Biden.

China, Taiwan, Israel, Russia, Iran, and North Korea are all on the watch list. The inclusion of South Korea on the list has sparked controversy in Seoul, which stated that it had not received any notification from Washington.

For some time, South Korean officials have increasingly suggested the idea of pursuing their own nuclear weapons. Last December, South Korean President Yoon Suk Yeol issued a martial law decree, plunging the country’s leadership into a crisis.