North Korea has constructed a new two-storey uranium enrichment facility at its main Yongbyon nuclear complex, according to the International Atomic Energy Agency, marking a significant expansion of the country's nuclear weapons production capacity.
The building is reportedly capable of housing up to 28 centrifuge cascades used to enrich uranium. Rafael Grossi, head of the IAEA, described the development as a cause for "serious concern" in a statement released this week. The agency, which has had no inspectors in North Korea since being expelled in 2009, relies on satellite imagery to monitor nuclear activity.
In a report published late last month, the IAEA also noted that Pyongyang has begun operating an expanded annex at another enrichment site in Kangson, near the capital. These findings demonstrate a sustained and deliberate expansion of North Korea's nuclear infrastructure in violation of international agreements.
What does this facility mean for North Korea's weapons capability?
The new Yongbyon building significantly increases North Korea's ability to produce weapons-grade nuclear material. According to VERTIC analysis from June 2026, the addition of this facility pushed North Korea's total enrichment capacity to approximately 100 tonnes of separative work units per year, which could translate to roughly 375 kilograms of weapon-grade highly enriched uranium annually.
The Kangson enrichment facility operates at substantial scale as well. A March 2026 assessment determined that the Kangson enrichment hall contains approximately 3,936 G2-type centrifuges arranged in 24 cascades, with an estimated output of about 70 kilograms of highly enriched uranium per year.
How many enrichment sites does North Korea operate?
North Korea now operates at least three known uranium enrichment facilities. The original Yongbyon complex has been expanded with the new two-storey building. The Kangson facility near Pyongyang began operations in January 2026 after an annex was constructed there in 2024. Additionally, South Korea's Unification Minister revealed in March 2026 that North Korea is running a third enrichment facility in Kusong, expanding the known network of production sites.
Edward Howell, a lecturer at the University of Oxford, emphasised the difficulty of monitoring North Korea's full nuclear programme. "What makes North Korea's nuclear programme so concerning is that many of its facilities are unknown, concealed, and thus difficult to target," he said. "Beyond Yongbyon, we know that other facilities exist: Kangson, for instance. The embeddedness of North Korea's nuclear doctrine within its foreign and domestic policy means that we should expect there to be more concealed production sites."
When did North Korea acknowledge its enrichment programme?
North Korea publicly acknowledged a uranium enrichment facility for the first time in September 2024, though it did not disclose the location. That acknowledgement is now being linked to the Yongbyon site described by the IAEA and international media reports. In June 2025, the IAEA said that North Korean leader Kim Jong Un visited a "newly inaugurated nuclear materials production factory" on 3 June, which it identified as the Yongbyon enrichment facility.
Kim praised the country's "greatly expanded production capacity" during that visit, stating that this would "offer the possibility of carrying out larger plans," according to the agency's report. Recent satellite analysis from April 2026 confirmed that the Yongbyon building was essentially complete and included support structures such as a standby generator, administration and engineering support facilities, and a vehicle shed.
What violations does this represent?
"The continuation and further development of the DPRK's nuclear programme are clear violations of relevant UN Security Council resolutions and are deeply regrettable,"Grossi said in his statement. The IAEA first referred to the existence of the building in June 2025, though Grossi had mentioned the possibility earlier in the year.
In April 2026, the IAEA said that North Korea had made "very serious" advances in its ability to produce nuclear weapons and that activity had increased at Yongbyon's reactor, reprocessing unit, and light-water reactor. The agency had been tracking the new Yongbyon building, noting similarities to the Kangson enrichment site, which reinforced the assessment that North Korea is expanding capacity across multiple facilities.
How does North Korea fund its nuclear programme?
Despite operating one of the world's poorest economies, North Korea allocates substantial resources to its nuclear arsenal. A 2022 report by a non-proliferation think-tank estimated annual spending on the nuclear programme at $640 million. This investment has accelerated under Kim Jong Un, who has overseen a record number of missile tests since taking power.
North Korea has conducted six nuclear weapons tests, the most recent in September 2017. The country has fired numerous intercontinental ballistic missiles since beginning long-range system testing in 2017. North Korea declared itself a nuclear power in 2022 and vowed never to relinquish its weapons, of which it is estimated to possess dozens.
What diplomatic efforts are underway?
In August 2025, South Korea's president Lee Jae Myung proposed talks with North Korea on officially ending the war between the two countries. He suggested that such negotiations could serve as a forum for discussing "effective ways to halt the advancement of the North's nuclear capabilities." North Korea has not yet responded to the proposal.
Lee has previously stated that Pyongyang was producing 15 to 20 additional warheads annually. He told the BBC last year that he would support a deal between US President Donald Trump and Kim to freeze production, though no such agreement has materialised.
What happens next?
The IAEA Board of Governors meeting scheduled for June 2026 represents the next major forum where Grossi is expected to brief member states on North Korea's expanding enrichment programme. The international community will continue to monitor satellite imagery and intelligence assessments as North Korea pursues what appears to be a deliberate and sustained expansion of its nuclear weapons production capacity across multiple sites.
Key Facts
- North Korea has built a new two-storey uranium enrichment facility at Yongbyon capable of housing up to 28 centrifuge cascades
- The country operates at least three known enrichment sites: Yongbyon, Kangson, and Kusong, with combined estimated capacity of roughly 375 kilograms of weapon-grade uranium annually
- North Korea publicly acknowledged uranium enrichment for the first time in September 2024 and declared itself a nuclear power in 2022
- The IAEA has no inspectors in North Korea since 2009 and relies on satellite imagery to assess nuclear activity
- South Korea proposed talks in August 2025 to discuss halting North Korea's nuclear advancement, but has received no response
