While I have zero knowledge of our electrical distribution system, I can't believe that our grid doesn't have some major circuit breakers in place. However, the North East region went dark a couple/few? years back. So, I might be wrong.
The transformers are a different ballgame.
“The transformers are a different ballgame. “
As you pointed out that the nuke guys (I’m one of them) are pretty smart, so are our infrastructure guys.