Location: Approximately 150m to 300m southeast of the Radiochemistry Laboratory, in Pun’gang-chigu (分江地區), Yŏngbyŏn-kun (寧邊郡), North P’yŏng’an Province (平安北道), North Korea

Subordinate to: Probably the Yŏngbyŏn Nuclear Research Center (寧邊原子力硏究센터), General Department of Atomic Energy (原子力總局), Cabinet (內閣)

Size: Two-story building, about 18 meters high, 24 meters wide and about 50 to 67 meters long. The first floor is reportedly underground and the second floor is at ground level.

Primary Function: Storage of liquid and solid nuclear waste

Description: North Korea completed construction of Building 500 sometime between the late 1980s and 1990. The first floor of the building is suspected of having four large compartments for liquid waste storage tanks and six smaller compartments for the storage of containerized solid wastes. This floor is also covered with slabs, probably for shielding any radiation leaks. There are also reports that claim the first floor is suspected of having a small-scale reprocessing facility. The second floor reportedly has a 20- to 30-ton bridge crane for handling solid waste containers.

In late 1991, a US reconnaissance satellite revealed that North Korea was digging trenches between Building 500 and the Radiochemistry Laboratory. The US Central Intelligent Agency (CIA) concluded that North Korea tried to conceal the linkage of the two facilities by burying the pipes before IAEA inspectors arrived for the IAEAs third ad hoc inspection conducted in September 1992. The pipes had apparently connected the two facilities around the time Building 500 was constructed. The US satellite imagery also revealed that North Korean workers were covering the outside area of the building with concrete slabs and piling dirt around the compartments at the lower level to conceal the existence of the first floor. When the IAEA inspectors visited the “new” ground level of the facility, North Korean officials denied the existence of a basement, and refused access to anything under the ground floor of the building.

In February 1993, the IAEA passed a resolution that demanded North Koreas acceptance of a special inspection of Building 500 and the Undeclared Waste Storage Facility, which is also located in Yŏngbyŏn, within a month. Following the IAEA’s resolution, North Korea deployed tanks around both facilities to emphasize the appearance of military sites. North Korea then turned down the IAEA’s request for the inspections, and subsequently declared its intention to withdraw from the Nuclear Non-Proliferation Treaty (NPT) on 12 March 1993. North Korea suspended its withdrawal from the NPT in June 1993, but has consistently refused IAEA requests to inspect this waste site. Under the terms of the Agreed Framework, North Korea is required to accept IAEA inspections of this facility when a significant portion of the light water reactor project is completed, but before delivery of key nuclear components.