It is the Ukrainians that are shelling the plant. The Russians have been in control of the area for some time now. They have no reason to shell it. Sometimes the Ukrainians said they were shelling it, because Russians had military installations there. Other times they say the Russians are shelling it. It makes no sense for either side to shell it. But even less sense for the Russians to do it. They are in full possession of it. The only Russian military in it are a sensible number of guard personnel. Ukrainian plant workers are still on site to keep it running.
So let the flaming begin…