Thinking the Russians will set off a nuclear catastrophe in their backyard makes as much sense as any of you firing at a nuclear weapon in your backyard.
Obviously, they know about the reactor's fail-safe's. They know they aren't causing a nuclear catastrophe in their own backyard.
Once again, Putin is piling on to his bluffing.
The Zaporizhzhia Nuclear Power Station built from 1980-1986 by the former Soviet Union. It was not even Ukrainian. But it just happened that it was built within Ukraine's current border.
The Soviet or the Russians built it. They know the best.