... still hard to wrap my head around the idea of no fuel being burned- just lots of hot air! Atomic reactors and airplanes do not mix. One is crazy heavy and bulky! The opposite of what you want an airplane to be! The idea of flying around forever on a handful of uranium pellets sounds very cool! But more efficient jet engines and (the less crazy idea) of transferring fuel from a tanker airplane won out.
Also; nobody really needs to fly around the world several times without landing. The need is to go to a destination; to visit or bomb. The need for this type of technology was short lived. Soon surpassed by the range and speed of missiles.
The more I look at Cold War nuclear war technology, the more I find myself repeating the phrase "it only has to work once!"
(note: this illustration clearly shows the British Saunders-Roe 'Princess' flying boat. Though obsolete before finished, it was of interest to American mad-scientists who saw it's vast size as possibly able to accommodate a nuclear power plant.)