Ukraine tried to claim that the NPP was a legitimate military target.

As CNN explained:

Kyiv has repeatedly accused Russian forces of storing heavy weaponry inside the complex and using it as cover to launch attacks, knowing that Ukraine can’t return fire without risking hitting one of the plant’s six reactors. Moscow, meanwhile, has claimed Ukrainian troops are targeting the site.

It is interesting that the CNN article — in a back-handed way — confirms that the Ukrainians are shelling the plant while “knowing that Ukraine can’t return fire without risking hitting one of the plant’s six reactors”.