KYIV, Aug 19 (Reuters) - Ukraine's Energoatom state nuclear company said on Friday Russian forces planned to switch off the functioning power blocks at the Zaporizhzhia nuclear power plant and to disconnect them from the Ukrainian power grid. In a statement, Energoatom said it believed Russia, which controls the power plant in southern Ukraine, was preparing to conduct a "large-scale provocation" there. Moscow itself accused Kyiv of preparing a "provocation" at the site on Thursday. (clip) Turning the plant off would pile new pressure on Ukrainian supplies, particularly in the south. Ukraine is already bracing for its most difficult winter...