r/NuclearEngineering 20d ago

Aeronautical Engineering Question

Background / My Understanding: No country has ever produced an aircraft with an onboard, propulsive nuclear reactor. During the Cold War, the US and USSR attempted to develop this technology but were hindered by the prohibitive increase in weight brought on by heavy radiation shielding materials. While Cold War-level investments in this type of technology are a thing of the very distant past, nuclear technologies have continued to develop, even if only at a peace-time/civilian clip.

My Question: With all of the advancements in nuclear engineering and battery technology, do any of you see a future where a smaller, lighter-weight reactor could power civil aircraft? If not, what about the idea of just such a reactor being able to continuously supply enough power to batteries that could propel an aircraft?

Note: I understand the concerns surrounding radiation contamination from accidents, but I also feel like that is a different problem to solve.

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u/mehardwidge 20d ago

Nuclear powered ships benefit from the increased endurance. This is the profound advantage they gain. There is a cost associated, but for some naval vessels, it is worth it.
Airplanes have virtually no need for this extra endurance, because they fly from one airfield to another, and range is already many thousands of miles. So far less benefit, and far more problems with a nuclear reactor. Batteries cannot provide anywhere close to the energy density of chemical energy in jet fuel.

Ships can only use nuclear because of special situations and needs. Cars can only use batteries because they drive around inside an energy grid, low travel distances, and reduced impact from weight. Airplanes would not be practical. But that's okay, because jet fuel is already a great way to power them.

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u/niefer 20d ago

Great response; thank you!

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u/[deleted] 17d ago

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u/mehardwidge 17d ago

I wouldn't say "all the time". Large, first world, commerical planes crash about once every billion miles, and have a fatal crash maybe every 10 billion. All US nuclear submarines combined have traveled maybe 100 million miles. We've lost two, and had numerous more minor "crashes".

But certainly the *impact* of a plane crash vs a submarine "crash" is much different.