I was reading a book about the history of nuc;lear power, and was intrigued to find out that the Air Force tried to develop a nuclear powered jet engine in the 1950’s! How they thought this would ever work is beyond me…a nuclear reactor weighs a lot, and needs shielding (so tha people nearby don’t get fried). I understand the work progreesed to the point where prototype engines were tested-and they spewed radioactive contamiation all over the place! They even had the reactor in a conventional bomer-if that plane had crashed, it would hae contaminated a huge area.
So, could this thing have ever worked? And, what was the point? Yo had a plane that could stay aloft indefinitely-what advantage is that?
i don’t know nearly enough to comment on the logistical probability of the nuclear power side of things, but as for why you might want to have an aircraft that never had to come down, that would make a squadron of bombers impossible (almost) to destroy on the ground.
You also had airborne command posts (Looking Glass being the one I can recall right now) that would be essentially immune to ground based ICBM attacks, and thus increase our own capabilities in re: a counter attack.
That, and the ability to take off from Nevada, fly to Moscow, drop a bomb, and return without having to set up strategic refueling is a HUGE bonus.
The US aircraft was the NB-36, by the way. IIRC, the Russian equivalent didn’t have the necessary shielding, and that was the one that had radiation leaks.
Not an airplane, but my favorite example of cool but amazingly dangerous and seemingly impractical propulsion is Project Orion which can theoretically be (and works most efficiently when) build to enormous scale.
Note that this is a design powered by over 1000 nuclear bombs.
Here’s an article, complete with a copy of the GAO.
The advantage was that in the pre-ICBM days, it would be a very useful to have planes that could loiter for weeks right outside Soviet airspace, waiting for the balloon to go up. Once we had ground based & sub based missiles that could reach the Soviet Union, a nuclear powered bomber became pointless.
We are now expending a lot of money to develop drones with loiter times measured in days. Long loiter has a lot of miitary utility.
During the optimistic phase of nuclear power, there was a lot of expectation that eventually lighter shielding would be developed. So the reactor + shield would be much lighter than a convetional engine + fuel design. All that weight saved turns into more weapons load.
So the idea wasn’t as crazy as it now seems. The pendulum on attitudes to radioactive hazard has swung from waay to optimistic in the 1950s to waay too pessimistic in the 1990s.
The other perceived advantage when the programme was started in the 1940s - apart from “nuclear is new and cool” - was the range. Early jet engines were very inefficient meaning pure jet aircraft had limited operational ranges (hence the B36 with its mix of prop engines for cruise and jet engines for high speed dashes into enemy territory). The thinking was that a nuclear jet bomber would have the range and the speed. By the time they had a working system jet engines had improved so much you didn’t need the weight and complications of a nuclear engine.
X-39 atomic aircraft engines on display at EBR-1 near Arco Idaho.
As far as reactors being too heavy or too dangerous, thats not true. Submarines work off reactors. All manner of spacecraft work off reactors and so do old Soviet lighthouses. These small reactors are safe. I could see a blimp or a drone thats nuclear powered. I wouldnt be surprised if such drones already existed.
I disagree. A submarine-sized nuclear reactor is still far to big and heavy to fit on even the biggest plane, and the “atomic batteries” used for space probes don’t provide enough power to propel a jet. Those would provide a few hundred watts – enough to run the cabin lights on your plane, and not much more…
“Too heavy” for a submarine or a battlecruiser is not the same as “too heavy” for an aeroplane.
Well, from this page the NB36 would have used a direct-cycle engine, meaning air taken in through a conventional turbine compressor, run through the guts of a nuclear reactor to heat it, and then exhaust it (again, through a conventional turbine). If that is the case, it would probably have left a fairly decent radioactive trail if they had ever got as far as switching the engines from the ‘kerosene’ setting to ‘nuclear’.
That they also felt the need to replace the crew compartment with an 11-ton radiation-shielded bunker suggests that in ‘active’ mode the reactor would have emitted a lot of radiation outside the airframe - possibly not a big deal at 20,000 feet but a bit disconcerting if e.g. the reactor didn’t shut down properly and you wanted to land the thing without irradiating your ground crew and anyone living under the approach path.
Factor in the size, complexity, risk and cost, and the disadvantages were even more compelling than the advantages, so it’s hardly surprising they gave up.
I remember reading that after the crewed nuclear aircraft didn’t pan out, they looked at what we would call a nuclear-powered cruise missile. No shielding needed for operation, because there’s no crew. Turned out to be so radioactively-dangerous that it didn’t actually need a warhead; it could just fly around enemy territory and poison it.
Here’s an article, originally published in Smithsonian Air & Space magazine on the Pluto missile – a weapon so wonderfully horrendous that it’s a particular favorite of mine.
The intent was that it would hug the treetops at Mach 3, incidentally pummelling anything it flew over with its shockwave and irradiating it with its ramjet exhaust, while lobbing nuclear bombs at multiple targets on its path – less a cruise missile than a robotic bomber, unhindered by a fragile human crew. Only when out of bombs would it dive itself into a final target, effectively bludgeoning that and irradiating the area with its fuel pile.
The trail of radioactive spew both made it impractical to test Pluto and complicated the use of it to the extent that one would want to avoid flying over friendly nations and troops. It was sort of a technological equivalent of a Viking “Berserker” – Turn it loose on your enemy and stay far away.
I think you mean this article. Truly terrifying and awesome.
DOH! Thanks.
>“atomic batteries” used for space probes don’t provide enough power to propel a jet.
Thats fair. I specifically mentioned blimps because youre getting at most 1,000 watts out of these things and lift is going to be an issue. I should have been more clear. What I was responding to was the hysterical idea that nuclear powered craft are these dangerous polluting machines, when in fact nuclear powered craft are incredibly clean and safe and so prevalent in subs and spacecraft we dont even think about them.
I guess it depends on the design. Space probes that use nuclear fuel don’t have a reactor in the traditional sense - the radiation gives off heat and that provides a small but steady amount of power to the craft.
Subs are similar to regular power plants - they have an enclosed system where steam spins turbines. Everything is contained internally.
How would a nuclear aircraft engine work? Would the air the compressor scooped up act as the coolant and moderating medium? If so, you’re spewing out whatever waste the reactor generates into the air. I would imagine that some sort of enclosed turbine system like you’d find in a sub would be prohibitively heavy.
Oh, I agree with that absolutely. But to get a safe, clean reactor you need huge slabs of lead and steel or concrete shielding – which easily fits on a cruiser or submarine. Without that shielding, a reactor does spew out huge plumes of radioactive death. Part of the idea to put a reactor on a plane was to cut down on weight by just shielding the crew compartment, which leads to the comments that such a plane would cook the ground crew in horrible ways.
With an RTG reactor you dont need tons of shielding, its shielding is very light. I dont see a good reason why a small RTG pushing out a few hundred watts could potentially power a blimb’s propellers with the electricity it provides, perhaps with a diesel motor backup in case more power is needed. It would be clean and could provide power for 50 years.
I guess a few hundred watts really is nothing when youre burning fossil fuels and accept x amount of lung cancer as acceptable.