Except nuclear plants have to be kept cool. Even with the multiple generators, and multiple safety generators, and battery banks, if the multiple lines bringing power in from outside sources are blown up the plant cooling can only last as long as their diesel and battery banks last. Most people have no idea that nuclear plants rely on multiple external power sources to make sure cooling works. They can use their own power while everything is normal, but when the plant has issues they absolutely need external power or things eventually turn very very bad.

If Russia or Ukraine wants to play with shutting down a nuclear power plant it will not end well. They will become a complete outcast in the world.