North Korea Expands Uranium Enrichment Capacity at Yongbyon and Kangson

The International Atomic Energy Agency (IAEA) has identified a newly constructed two-story building at the Yongbyon nuclear complex that can accommodate up to 28 centrifuge cascades. Construction began in December 2024, the exterior was finished in May 2025, and power, backup generators and cooling units were added later. Photographs released by North Korean state media after Kim Jong un’s visit on June 3, 2026 show cascades installed on both floors. The IAEA also reports that an annex at the Kangson enrichment site, built in 2024, has been operating since January 2026.

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North Korea’s nuclear monitoring by the IAEA has relied on satellite imagery and open-source material since inspectors were expelled in 2009. Yongbyon already hosts a first uranium enrichment facility (U-EF 1). The regime declared itself a nuclear-armed state in 2022 and has conducted six nuclear tests, the last in September 2017. Recent missile-test activity and statements by Kim Jong un indicate a policy of “exponentially strengthening” the nuclear force.

North Korea Constructs New Uranium Enrichment Facility at Yongbyon, IAEA Chief Expresses Grave Concern United24 MediaThe GuardianThe Straits Times

• Centrifuge capacity: Up to 28 cascades (? 4,592 centrifuges) could be housed at the new Yongbyon building.

North Korea: IAEA Identifies Second Uranium Enrichment Facility at Yongbyon

• Potential HEU output: A 2025 analysis by the James Martin Center for Nonproliferation Studies estimates the Yongbyon capacity could yield about 85 kg of weapons-grade highly enriched uranium per year, enough for three to four additional warheads.

The Guardian

• Warhead estimates: South Korean Defence Minister Ahn Gyu-back told lawmakers that North Korea may possess 80–120 nuclear warheads, a figure based on private research organisations, contrasting with the 57 warheads cited by former U.S. President Donald Trump in the same month.

North Korea builds new uranium enrichment facility, IAEA says

He added that the development is “deeply regrettable.”

The Guardian

South Korea’s defence ministry, through Minister Ahn Gyu-back, emphasized the higher warhead estimate and warned that the military cannot independently verify the numbers.

The Guardian

• Warhead counts: The 57-warhead figure reported by former President Trump differs from the 80–120 estimate cited by South Korea’s defence minister, reflecting a lack of transparent data.

North Korea builds new uranium enrichment facility, IAEA says

• HEU production: The IAEA has not provided its own estimate of how much highly enriched uranium the new facility can produce, while the James Martin Center offers a speculative 85 kg per year.

IAEA: NK's Yongbyon facility can hold up to 28 centrifuge cascades

• Centrifuge inventory: The agency cannot confirm the exact number of centrifuges installed in each cascade, nor their operational performance, leaving the true enrichment rate uncertain.

IAEA: “North Korea’s New Enrichment Facility in Yongbyon Can Accommodate Up to 28 Sets of Centrifuges”

The IAEA’s findings were submitted to its Board of Governors on August 28 and accompanied a statement to the agency’s 70th General Conference, scheduled for later in September in Vienna. Safeguards for North Korea are on the provisional agenda, indicating that further diplomatic and technical discussions will follow.

North Korea Expands Uranium Enrichment at Yongbyon and Kangson, IAEA Says

• “What makes North Korea's nuclear programme so concerning is that many of its facilities are unknown, concealed, and thus difficult to target,” — Edward Howell, a lecturer at the University of Oxford

North Korea builds new uranium enrichment facility, IAEA says