Recent commercial satellite imagery indicates continued construction activity at North Korea’s Uranium Enrichment Plant (UEP) at the Yongbyon Nuclear Scientific Research Center. Imagery from October 1 indicates that previously reported construction in an area just north of the plant’s Cascade Hall #2 has recently been covered, concealing details of the building’s layout and construction. Prior to this concealment, the floor space measured roughly 42 meters by 15 meters (including walls), with six circles each approximately three meters in diameter observed at the east end of the building. The purpose of the building is still unknown and may be harder to determine via imagery going forward.
There are several possible functions for such an extension. One option, assuming that North Korea is producing low-enriched uranium at two enrichment halls, is that the extension could also be used to enrich low-enriched uranium to weapons grade (high-enriched uranium) as it becomes available from those two cascade halls.
Figure 1. New covering over construction area visible at UEP.