Free Republic

I am writing a story and it has to do with a crisis happening in the USA. In a previous thread I asked for (and received in spades) info regarding what would happen if none of the employees of our power grid showed up for work. So now I am looking for info on the "Internet Kill Switch" OK so let's say there is an actual emergency where the President needs to shut the Internet off in the USA. For purposes of this research subject it doesn't matter if he has legal or moral authority to do so only that...

I am working on a story and in the story people don't show up for work anywhere including the power plants (electrical generation). So what happens? For instance will a Nuke plant shut down safely if no one shows up ever again or will the plant become unstable after a time with no human supervision and it would go into meltdown and/or releases some form of nuclear exhaust? If so what are we talking here? China Syndrome or something like the what happened in Japan after the quake? A coal fired plant or a gas fired plant I would surmise...