After examining lists in various reports and at government and NGO websites, I've determined that as of March 2011 there are 65 operating nuclear power facilities in the U.S. Each facility has from 1 to 3 reactors for a total of 104. This number does NOT account for those reactors that are decommissioned, reactors at research and university facilities or all of the nuclear waste at various locations around the United States. In time, I will make shapefiles available of these other nuclear hazards. See below for an updated nuclear and seismic hazards shapefile and spreadsheet that you may download and use as you wish.
Here's the new map based on this updated data:
For now, you can download an updated shapefile and speadsheet that shows all of these nuclear reactors that are currently operating in the U.S.
Also, I've added some map images in PNG, TIF and Acrobat PDF formats that you may download and use as you see fit.
Download the U.S. Nuclear Facility and Seismic Hazards Shapefiles, Maps and Images