Images of work being done at the Yongbyon facility can be viewed at the Institute for Science and International Security "New Satellite Image of Construction at North Korea Nuclear Site":
ISIS has obtained commercial satellite imagery taken on March 8, 2011 of the Yongbyon nuclear center in North Korea showing progress in the construction of what North Korea has stated will be a light water reactor (see figure 1). A cylinder can be seen in the image and it measures approximately 21 meters across. At this diameter, the cylinder would be too large for a light water reactor containment vessel. It could, however, be part of the containment structure for a light water reactor. There is new excavation next to the cylinder as well (see figure 1).