Yongbyon Declassified Part V: Expansion Begins Across the Kuryong-gang

Nuclear Weapons
, by Collected eleven months after the image provided in Part 4 (December 10, 1967) this November 21, 1968 KH-4B image of the Yongbyon Nuclear Research Center does not show any significant developments in the operations (with the IRT-2000 research reactor), support or administrative/laboratory areas. It does, however, show continuing development within the village of Sang-dong and the early stages of construction for a new road bridge across the Kuryong-gang in the Pungang-ni area that will connect the support area to the opposite side of the river. Taken as a whole, these developments represent both continuation of a first-phase construction project for the facility and the earliest infrastructure development stages within a longer-term plan for future expansion.

Pakchon Uranium Concentrate Pilot Plant

Analysis, Nuclear Weapons
, by and The Pakchon Uranium Concentrate Pilot Plant is one of only two declared and known uranium concentrate plants in North Korea (Pyongsan Uranium Concentrate Plant at Pyongsan is the other). This facility was used for Yellowcake production at least through the mid-1990s, and therefore would require inspection under any new U.S.-DPRK denuclearization declaration and agreement as it has not been subject to international inspection for over 25 years since IAEA visits to the site as part of the Full Scope Safeguards Agreement process in 1992.

Yongbyon Declassified Part IV: Continued Construction Observed into 1967

Nuclear Weapons
, by Acquired almost two years after the image provided in Yongbyon Declassified Part III (February 11, 1966), this December 10, 1967 image of the Yongbyon Nuclear Research Center is one of the first acquired by the improved reconnaissance KH-4B. Among other improvements, the resolution of the newer KH-4B was 1.8 meters versus 2.7 meters of the earlier KH-4A allowing for considerably better image quality.

Yongbyon Declassified Part III: Significant Construction of Facilities at Nascent Yongbyon Nuclear Site by 1966

Nuclear Weapons
, by Acquired seven months after the image provided in Yongbyon Declassified Part II (August 23, 1965) this 2.7-meter resolution image covers the Yongbyon area on February 11, 1966. While the general area remains primarily engaged in agricultural activity typical of rural North Korea during the 1960s, significant construction activity is observed at the nascent Yongbyon Nuclear Research Center and adjacent village of Sang-dong.