Did you know that planes almost carried nuclear reactors? Here's what nuclear-powered planes might have looked like.
At one time, engineers spent over $1 billion (in 1950s money) investigating the feasibility of atomic-powered airplanes to eliminate the need for refueling. At a time before the various nuclear disasters of the later 20th century, the public was less aware of the dangers posed by atomic accidents. This was when support for such technology reached its pinnacle, a time where trains, homes and even cars were looking to be powered by the atom.
The modified Convair B-36 that carried a nuclear reactor over the US
The idea was that new aircraft that avoided the need to refuel could fly for weeks or months at a time. It was thought that they would have a strategic advantage as a nuclear deterrent. This was because they could continuously fly close to enemy territory on standby before being ordered to strike a target.
Science fiction of the 1960s regularly depicted future aircraft as nuclear powered whilst also depicting the risks they posed
How Nuclear Powered Jet Engines Work
There are two types of nuclear jet engines. The first is a simple direct cycle jet engine. This engine theoretically resembles a conventional jet engine although without the combustion chamber. The aircraft would gather air through the intake, much like a conventional jet, but then redirect that air into the reactor core. This would heat the air which would then be expelled from the exhaust of the engine. Essentially, the reaction would replace fuel to heat and expand air needed to produce thrust.
The problem with the direct cycle engine is that any plane using one of these engines would leave a trail of radioactive air in its wake. This was because any air pumped through the engine would become irradiated.
The HTRE-3 nuclear aircraft engine
The second concept for a nuclear jet was the indirect cycle engine. This type works by introducing a liquid pumped around the core and into a heat exchanger. The liquid in this chamber would heat and expand air drawn into the engine resulting in thrust from the exhaust. This method, avoiding sending air into the core, would have been far less damaging to the environment.
Two direct cycle nuclear engines
The First (and Only) Nuclear Aircraft
Although there haven't been many aircraft fitted with nuclear reactors, there have been a few. One of the first was the American Convair NB-36H. This was a modified Convair Peacemaker fitted with a proof-of-concept reactor and a huge amount of protective shielding for the crew compartment.
The 'Crusader' did fly with a reactor but never had nuclear engines.
By the time the Berlin Wall fell in 1989, information about Soviet experiments with nuclear-powered aircraft from the 1950s and 1960s was revealed to the west. Although at the time the US government had believed that the USSR had not been able to fly aircraft with nuclear engines, it became known that one such aircraft had existed. This was the Tupolev Tu-119, a plane derived from the Tupolev Tu-95 bomber. It first flew in 1961. In all, it made over forty flights.
The TU-95 bomber was the type of aircraft modified into the nuclear-powered TU-119
Nuclear Cruise Missiles
Although work on nuclear-powered planes thankfully came to an end due to a combination of cost, environmental and safety concerns, the appeal of using a nuclear reactor inside an aircraft still remains. For military applications, unmanned drones could be kept flying on the power of the atom. Cruise missiles too could, worryingly, be almost permanently airborne waiting for a command to strike anywhere across the world.
It's probably a good thing nuclear-powered planes never came to fruition. Whether in military or civilian use, the technology is surely not without its significant risks. However, what with a new opportunity for use within the militaries of the world, we may not have seen the last of the atomic aircraft.
Article by James Whomsley
Editor of FliteTest.com
YouTube Channel: www.youtube.com/projectairaviation