Wu is dumb as usual, the reactor is not connected to facebook, it's not on the internet, nothing of important is on the internet because it would be dumb as shit.
It seems to be called 'air gapping' now or some shit, separate circuit in the past maybe, but it's been going on forever and the principle is that if you have something highly valuable or sensitive that you don't want stolen, or tampered with, or seen/read then you don't connect anything on that network to the internet! There will be, and forgive me because I can't remember the translation or terminology, "hard lines" or dedicated connections that connects facilities in a huge local area network and it can span continents. And shit is locked down tight.
That is pretty much the dark web.