N.S. Savannah was the first, and so far the only, commercial (that is, non-military) nuclear-powered ship built in the United States.  She was developed as the centerpiece for President Dwight Eisenhower's "Atoms for Peace" program of the late 1950's which was intended primarily to get military know-how into the civilian sector so that it could demonstrate its worth in all sorts of applications.  The NS Savannah was to be the only mobile application, and was designed to carry both passengers and cargo to demonstrate efficiency in both areas to prospective investors and customers.

You can find a lot of information about the ship on the net.  It's still around; although it was a display at the Patriot's Point Naval Museum in Charleston, South Carolina for many years (that's where I worked on it, but more of that later) it's not there any longer.  The Maritime Administration's agreement with Patriot's Point was terminated a few years back and the ship was towed away.  Presently, MARAD is trying to complete the complete decommissioning of the reactor plant (it's been defueled since it was taken out of service) and is working on EPA and NRC compliance for cleanup of the whole plant.  It appears that this beautiful ship will be preserved -- in fact it seems to have a better chance than the old, conventional USS United States!

Click here to see the official MARAD site on the NS Savannah and its progress.  Click here for a great MARAD site on the history of the NS Savannah and the project to save it.
Quick NS SAVANNAH facts.  Laid down May 22, 1958; built by New York Shipbuilding Corporation.  Launched July 21, 1959.  Reactor tested through April; ship turned over to MARAD in May 1962.  Passenger service stopped in 1965; cargo only thereafter.  Removed from active service in 1971.  Agreement signed and ship sent to Patriot's Point before end of 1981.  Removed from museum 1994, placed in James River Reserve Fleet.  Moved from reserve in 2002 when cleanup / restoration begun.
What follows is from my memory.  Please excuse any errors.
Back when I was assigned to a ballistic missile submarine in the US Navy, we ended up with quite an unusual job one off-crew period.  It seemed that the Patriot's Point Naval Museum had run into some trouble with the Park Service and needed someone to do some work for them.  They had little money to spend, and so they took advantage of the rather obscure program from the Charleston Naval Base that served basically as a community outreach.  Guys from the boats and from the surface ships from whatever squadron would go out in town and help do things like build playground toys for schools, or fix up and paint schools and so forth.  Anyway, somehow when our boat was in, word got to us from Squadron that the museum needed help.  The Chief of the Boat decided to refer the job to Reactor Controls Division.

We went there the first time and met up with the curator, who I believe was Joe Lund, in his office on the USS Yorktown and got the low-down on what he needed.  It seems that the Park Service was all over him because there were no public address systems on the display ships there (carrier USS Yorktown, destroyer USS Laffey, sub USS Clamagore and merchant nuclear powered ship NS Savannah being the prime displays at the time) and thus there was no way to warn visitors of any emergencies, or missing children or any such thing.  Mr. Lund decided to see if it wasn't possible to re-use the various ships' own IC systems patched together somehow, or else operated individually on each ship.  The stories on the carrier, destroyer and sub are interesting but not applicable to this story here.

Our only reward for our work was something I found priceless -- a tour of the engineering spaces of the Savannah.  Now, the Savannah had a glassed-in gallery deck above the engine room from where originally passengers could look down and see the space, which still existed but no one other than museum staff had been down there in years.  We were really getting a treat; at least that's what I thought.