If everything had worked perfectly, it still would have been a bum airplane." - Charles Wilson, Secretary of Defense

Back in the 1950s and 1960s, the United States attempted to design nuclear powered aircraft. This was part of a larger "nuclear craze" in the era where everything and anything was proposed to have nuclear technology applied to it. This led to all kinds of things like the Chrysler TV-8 and "peaceful" earthmoving construction projects. The only place where nuclear power or propulsion really took off was for large ocean going ships both for military navies as well as civilian tankers, cargo ships and icebreakers. Spacecraft technology was the only other "success story."

Nuclear powered aircraft, while more realistic than say nuclear cars, never quite caught on except for a few experimental engines and just one actual working aircraft. The most extensive efforts towards this during the Aircraft Nuclear Propulsion (ANP) program were the HTRE-2 and HTRE-3 experimental nuclear reactors with heat transfer assemblies designed for nuclear powered aircraft at the Idaho National Laboratory. Rather than burning fuel, the jet turbine would use the heat from the nuclear reaction to heat air sent through a compressor which would then be expelled as exhaust for thrust.

On of the more fascinating tests were the test flights of the NB-36H which while conventionally powered, flew while carrying a working nuclear reactor to test the protective shielding of the crew. It carried an air-cooled 1 megawatt reactor. The engineers and crew worked within a specially shielded nose cabin with 12-inch-thick lead-glass windows.

The project was canceled by the Kennedy administration a few months after taking office in 1961 citing high costs, poor management, and little progress towards a flight ready reactor saying:

At the time of termination, the Aircraft Nuclear Propulsion Program was still in the research and development stage, with primary emphasis on high performance reactors. Although a number of research and development achievements can be credited to this program, at the time of termination an airplane had never been flown on nuclear power nor had a prototype airplane been built. - Joseph Campbell, Comptroller General

and

Nearly 15 years and about $1 billion have been devoted to the attempted development of a nuclear-powered aircraft; but the possibility of achieving a militarily useful aircraft in the foreseeable future is still very remote. - John F. Kennedy, POTUS

Footnote: This post is a rework of a reddit post I made here a couple years back. It's not really meant to be a coherent or lengthy article but has some links and thoughts which I found interesting.

I know there are some Germans on Tildes, figure at least one of y’all might know. How does a typical Autobahn differ from a typical Interstate in design and construction? How often is repair work done and how long does it last? What work would be required to upgrade an Interstate to Autobahn standards?