I forget where I saw it, but someone drew up a list of every new energy plant that anyone had attempted to build in the US in the past 10 years or so. Just about everyone of them was either tied up by greenie activist lawsuits, or else the project had been abandoned because of too many greenie activist lawsuits. Nuke plants, coal plants, a coupla hydro dams, oil fields and refineries, anything and everything, it didn't matter to them. They just buried it in red tape and shut it down.
There are a handful of half-built nuclear reactors scattered about the country. They got the construction started, then the greenies attacked and shut 'em down.
The only real increase in domestic energy production has been achieved through upgrading and improving existing installations. Existing facilities aren't subject to nearly as many enviro regulations.
When I worked at the North Anna Nuclear Power Station, out in Mineral VA, there were two reactors onsite (finished in 1980 and 1982, IIRC). There were foundations for Units 3 and 4, as well - and there are photos of half-built containment domes and significant amounts of primary-side equipment inside the domes, which are no longer there. All that was taken down after lawsuits to stop construction and drum up public fear over nuke plants made it too expensive to finish two 900MWe power plants. Improvements to existing equipment over the years has increased the two units onsite from about 900MWe each to slightly over 1000MWe - and that's it.
They're now, twenty+ years later, putting a third unit (of a different design than the first two) on the site.
National security. There's this group of nasty nations called OPEC. Iran and Venezuela are building up their armies as we speak. The former is attempting to build nuclear weapons and long range rockets.
I can give you a darn good reason. Price. Why pay more for nuclear when coal can easily be made clean either through scrubbers or the burning of syngas? Why don't you like coal, anyway?
Because it's FAR from easy or cheap to make coal "clean", for one.
Because nuclear fission is, last I saw, BY FAR the cheapest major power option currently at hand, for two.
Because coal releases far more radioactive byproducts (as well as other unpleasant nonradioactives) to the environment as a result of normal operations, for three.
Is there a use for coal? Sure - especially since, as has been pointed out, you can get synthetic petroleum out of it (although I'm a little fuzzy on the process and attendant costs). Should it be a primary electric-grid source? Not IMO.