August M
South Korea’s long-standing push to build nuclear-powered submarines has gained new momentum after U.S. President Donald Trump signalled support for the project, easing restrictions on nuclear fuel that had blocked progress for decades.
A fast-moving shift in U.S. policy has opened the door for South Korea to pursue nuclear-powered submarines, a project long blocked by Washington.
The reversal — endorsed by President Donald Trump — is expected to alter military dynamics across Asia and intensify competition beneath the region’s waters, Reuters reported.
Seoul has argued for years that nuclear propulsion is essential to counter North Korea’s expanding undersea arsenal.
With U.S. restrictions on nuclear fuel now eased, South Korea’s programme is accelerating, even as analysts warn it could provoke China and pressure Japan to follow suit.
Rising regional stakes
Reuters notes that retired South Korean naval officers and defence experts expect an arms race, pointing to North Korea’s claim that it is developing its own nuclear submarine.
Some in Seoul believe Pyongyang may be receiving Russian technical support — a scenario the South Korean military says it is monitoring closely.
President Lee Jae Myung has framed Trump’s approval as a milestone that strengthens defence autonomy and improves flexibility at sea.
Nuclear-powered vessels can remain submerged far longer than diesel subs, giving Seoul more leverage in tracking North Korean boats.
Japan watches closely
Tokyo has been rattled by Washington’s shift, according to Reuters’ sources familiar with government discussions. Some Japanese officials assumed the U.S. would support a Japanese programme before South Korea’s.
While the defence ministry has not launched studies, Defence Minister Shinjiro Koizumi has said nuclear propulsion cannot be ruled out.
Experts told Reuters that such submarines would extend Japanese operations into the wider Pacific and, over time, could contribute to a second-strike nuclear capability.
China’s muted reaction
Beijing has publicly held back, but the think tank 38 North warned that opposition could harden quickly.
South Korean officials said President Lee assured Xi Jinping the submarines would serve only as a deterrent to North Korea.
Still, North Korean state media has warned the move could trigger a “nuclear domino” across the region.
Some analysts quoted by Reuters even floated the possibility of joint Japanese–South Korean development with U.S. backing, aligning the allies more tightly against China.
A long road, now accelerating
Only six countries currently operate nuclear-powered submarines, but Australia’s AUKUS partnership has already softened global resistance to sharing related technology.
South Korea explored the idea as early as 1994 and received quiet encouragement from Trump during Moon Jae-in’s presidency, though U.S. departments blocked progress at the time.
Reuters reports that Seoul has since developed core designs and is assembling a reactor, with officials saying a first vessel could be built within ten years.
A recent U.S.–South Korea fact sheet confirmed cooperation on nuclear fuel supply, which defence minister Ahn Gyu-back described as the “final piece” previously missing.
Washington has now openly endorsed the project as part of shared deterrence against China. As one former official told Reuters, “the train is already moving.”
Sources: Reuters.
