Suspected Uranium Enrichment Building at Yongbyon

• A review of available Maxar satellite imagery indicates the construction of a structure that is likely to be a new uranium enrichment plant to produce fissile material for nuclear weapons.
• A June 6, 2025, image locates the new building (39.785074 125.758882) in the southern section of the Yongbyon Nuclear Research Center.
• Longitudinal satellite imagery analysis shows that construction started in mid-December 2024. The building was externally completed by early June 2025, and internal construction continues.
• The imagery corroborates a recent statement by the International Atomic Energy Agency (IAEA) Director General revealing the construction of a new building at Yongbyon "which has dimensions and features similar to the Kangson [uranium] enrichment plant."
• The IAEA statement suggests that the new building may be intended to expand North Korea's uranium enrichment capacity, though further information is needed to confirm its intended use.
• Pyongyang has significantly augmented its weapons arsenal since Kim Jong-un and Donald Trump met seven years ago, with an estimated 50 nuclear weapons, including miniaturized tactical nuclear warheads, and enough fissile material for an additional 40 weapons. If the building at Yongbyon is indeed a new enrichment facility, we will see a substantial increase in the North Korean nuclear arsenal before the end of the decade.

On June 9, 2025, the International Atomic Energy Agency (IAEA) Director General Rafael Mariano Grossi stated that "the Agency is monitoring the construction of a new building at Yongbyon which has dimensions and features similar to the Kangson enrichment plant."¹ The statement suggests that the new building may be intended to expand North Korea's uranium enrichment capacity, though further information is needed to confirm its intended use. Both the new building at Yongbyon and the Kangson plant remain undeclared by North Korea. Director General Gossi emphasized that the "undeclared enrichment facilities at both Kangson and Yongbyon are of serious concern."²

A review of available satellite imagery indicates that the new building (39.785074 125.758882) is located in the southern section of the Yongbyon Nuclear Research Center. Externally, it measures approximately 48 by 120 meters as compared with the main building at Kangson (38.957175 125.611868), which externally measures approximately 50 by 115 meters.³

The location chosen for the new building was previously a small support compound approximately 480 meters north-northeast of the Radiochemistry Laboratory and approximately 1,800 meters north of the existing centrifuge hall. Initial construction activity was first identified in mid-December 2024, when a series of large square holes was excavated on the east side of the support compound. These excavations were typical of those used for pouring concrete footings for large buildings. This was quickly followed by similar excavation within the center courtyard of the original support compound and the razing of all but two of the structures within the preexisting compound.

Three months later, by April 2025, concrete footings had been poured, and a two-story steel-framed building, and what appears to be a large central hall, and a shallow-pitch blue roof were under construction. Concurrently, an approximately 603-meter-long security wall with one entrance was erected around the site.

A more recent image, acquired on June 6, 2025, shows that the new building is externally complete. Internal construction continues, as is evidenced by supplies and equipment on the ground adjacent to the building. Additionally, two small storage tanks have been installed on the south side of the new building, and construction of several new small support buildings has begun. A large area within the southeast corner of the security wall suggests that additional construction may be planned going forward.

Pyongyang has significantly augmented its weapons arsenal since Kim Jong-un and Donald Trump met seven years ago, with an estimated 50 nuclear weapons, including miniaturized tactical nuclear warheads, and enough fissile material for an additional 40 weapons. If the building at Yongbyon is indeed a new enrichment facility, we will see a substantial increase in the North Korean nuclear arsenal before the end of the decade.

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