South Korea says North operates four uranium enrichment facilities, signaling expanded nuclear program

South Korea said Thursday that North Korea operates four uranium enrichment facilities, expanding assessments that Pyongyang runs several covert atomic plants in addition to the widely known Yongbyon complex near Pyongyang, about 60 miles north of the capital.

Unification Minister Chung Dong-young told reporters that centrifuges at the four facilities are running daily, and he stressed the urgency to stop the North’s nuclear program. Chung did not identify locations beyond Yongbyon. The ministry also cited an assessment that the North possesses about 4,400 pounds of highly enriched uranium, a figure Chung attributed to civilian experts rather than directly to intelligence services.

If confirmed, the stockpile would mark a sharp increase in North Korea’s stock of nuclear material. By 2018, Stanford University researchers including Siegfried Hecker estimated the North had about 550 to 1,100 pounds of HEU, enough for roughly 25 to 30 nuclear devices. Nuclear weapons can be built from either HEU or plutonium, and Yongbyon houses facilities to produce both. The North has in the past shown photographs of what it described as a uranium enrichment facility—the first such disclosure since 2010—though the location and other details remain unverified.

North Korea’s leadership has prioritized rapid expansion of its nuclear arsenal, even as diplomacy with the United States and South Korea has stalled since 2019. Analysts say Kim Jong Un’s push could complicate any future talks, especially if he seeks sweeping sanctions relief in exchange for partial denuclearization. Foreign experts have long suggested that North Korea has built additional uranium-enrichment sites as a way to extend production beyond Yongbyon.

Centrifuges used for uranium enrichment can be housed underground and operate covertly, offering a way to extend the North’s program without immediate detection. Plutonium plants, by contrast, are larger and create more heat, making them easier to spot via satellite.

The North’s public posture since returning to office has been to resist diplomacy focused on dismantling its arms, while Kim has repeatedly stressed that he would not trade away an expanded arsenal for sanctions relief. He also said earlier this week that he still has good memories of talks with former President Donald Trump but urged Washington to drop its precondition that the North surrender its nuclear arms as a prerequisite for talks.

Analysts caution that independent confirmation of inventories is difficult, and estimates vary. Any possible talks with Washington or Seoul would likely hinge on security assurances and a path to sanctions relief as Kim seeks to maximize leverage in potential negotiations.