Satellite images have shown a "high level of activity" at North Korea's key nuclear facility, a U.S. organization said, as leader Kim Jong Un has ordered an expansion of the country's production of weapons-grade nuclear materials.The images taken in March suggest that completion of an experimental light water reactor at the nuclear complex in Yongbyon is just around the corner, Washington-based website 38 North, a group monitoring North Korea, said Saturday.Water discharges have also been "detected that could be associated with testing" the reactor's cooling system, the organization said, a…READ FULL ARTICLE