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NASA completes full-power tests of small, portable nuclear reactor

engadget.com

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Re: NASA completes full-power tests of small, portable nuclear reactor

#71

Post by TangoTrotFox »

ausjke wrote: post #66

can this be used for car/boat/etc-fuel somehow one day, then all gas-station will be run out of business and middle-east-plus-texas-oil-field all file for chapter-11? not sure how to prevent radiation though.

Something that's often left out in the discussion of nuclear because it's not an issue yet, is that nuclear fissile materials are also rare. If nuclear became the standard for energy production, the rarity of these materials would, in the longrun, end up creating more stupid games similar to what we play with fossil fuels today.

'Time do bring democracy to Australia!'

'Wait guys... what?? We are a democracy!!'

'Sorry, can't hear you over the sounds of FREEDOM coming your way!'

Re: NASA completes full-power tests of small, portable nuclear reactor

#72

Post by mcguire »

dukoid wrote: post #19
practice9 wrote: post #12

Earlier quoted context omitted.

It's a fascinating idea from science fiction perspective, but moving the Moon anywhere will probably have devastating effects on the Earth's biosphere

p.s. The process is shown in this documentary: https://www.youtube.com/watch?v=HE06rNkxlks&feature=youtu.be...

Thanks!

Re: NASA completes full-power tests of small, portable nuclear reactor

#73

Post by mcguire »

rbanffy wrote: post #62
asteli wrote: post #40

Earlier quoted context omitted.

The wiki page you linked specifically mentions deep space applications as a design goal. I'm not sure about the sodium heat pipes but the alcohol vapor heat pipes you see in electronics typically use an internal wick to return the working fluid.

Worst case scenario is you put the reactor next to the toilet, in the rotating part of the spacecraft, to solve the problem with convection... These two things are enormously simplified when there is gravity.

"Worst case scenario is you put the reactor next to the toilet..."

Please don't give any ideas to our collective employers.

Re: NASA completes full-power tests of small, portable nuclear reactor

#74

Post by bluGill »

netzone wrote: post #4

What would the effects be of releasing nuclear waste in space? Could we sent up all of our nuclear waste, put a rocket on it and just let it disappear into the distance?

Why would we do that? Nearly all of that so-called waste is recyclable for more energy than we got out of it the first time.

There is risk, but by coal is even more dangerous. The risks are all easy to mitigate if you use modern engineering.

Re: NASA completes full-power tests of small, portable nuclear reactor

#75

Post by fragmede »

jabl wrote: post #39
mkoryak wrote: post #33

I wonder how safe these are. Could I get one in my basement and stop paying nstar for the rest of my life? Would my neighbors complain much?

The black helicopter people might arrive and have a nice chat with you when they discover you ordered a bunch of HEU from aliexpress.

You misspelled http://www.unitednuclear.com ;)

Re: NASA completes full-power tests of small, portable nuclear reactor

#76

Post by hwillis »

coryrc wrote: post #22
telchar wrote: post #15

Earlier quoted context omitted.

Yes they are. An ideal stirling engine has the Carnot level efficiency, i.e. maximum theoretical efficiency for a heat engine. https://blog.mide.com/thermodynamic-theory-of-the-ideal-stir...

Except the ideal one doesn't exist and multistage stream turbines are more efficient in practice.

Definitely not at that scale. Small turbines have low efficiency because tip speed increases quadratically as they get smaller.

Re: NASA completes full-power tests of small, portable nuclear reactor

#77

Post by jabl »

ChuckMcM wrote: post #60

They nailed all their milestones. This is tremendously important work with regards to a future outpost anywhere and possible outposts on Earth. (Imagine how much fuel you wouldn't have to ferry down to Antartica each year to prepare for winter operations, for example). Now to ruggedize the heck out of it and make it easily transportable.

Not Antarctica but pretty close to the other end, this thing is being towed up there at the moment: https://en.wikipedia.org/wiki/Akademik_Lomonosov

(it's a fairly traditional PWR, though, so nothing new technology-wise per se)

Re: NASA completes full-power tests of small, portable nuclear reactor

#78

Post by reaperducer »

jabl wrote: post #39
mkoryak wrote: post #33

I wonder how safe these are. Could I get one in my basement and stop paying nstar for the rest of my life? Would my neighbors complain much?

The black helicopter people might arrive and have a nice chat with you when they discover you ordered a bunch of HEU from aliexpress.

Funny you should use the phrase "black helicopter." During the Cold War, the military used tiny nuclear reactors to power automated remote sensing stations in the Arctic. We called them "Power Pigs" and they were delivered by helicopter to very remote places.

They were fascinating little devices, and because of where they were placed, used the outside air/ice/snow/rocks for cooling.

Don't know if they are still being used, or what happened to the old ones, but they were very clever technology.

Re: NASA completes full-power tests of small, portable nuclear reactor

#79

Post by jabl »

TangoTrotFox wrote: post #71
ausjke wrote: post #66

can this be used for car/boat/etc-fuel somehow one day, then all gas-station will be run out of business and middle-east-plus-texas-oil-field all file for chapter-11? not sure how to prevent radiation though.

Something that's often left out in the discussion of nuclear because it's not an issue yet, is that nuclear fissile materials are also rare. If nuclear became the standard for energy production, the rarity of these materials would, in the longrun, end up creating more stupid games similar to what we play with fossil fuels today. 'Time do bring democracy to Australia!' 'Wait guys... what?? We are a democracy!!' 'Sorry…

It's usually left out of the discussion because it really is a non-issue long term as well. With breeder reactors (technology which already exists), Th in addition to U, U/Th extraction from seawater, we have enough fission fuel to power the entire planet at current levels for tens of thousands of years, if not indefinitely.

Re: NASA completes full-power tests of small, portable nuclear reactor

#80

Post by InclinedPlane »

syntaxing wrote: post #7

For those curious, this uses a nuclear reactor to power a Stirling engine.Stirling engines are a good choice because there is no mass transfer to create the work (i.e. no fuel needed, just heat). It only needs a temperature differential and sealed gas/liquid to work. I highly recommend to read more about Stirling engines since they are of one the most efficient form of work generation with just a temperature differen…

Stirling engines aren't that efficient but they are very reliable and capable of running for many years with zero maintenance. They compete with bimetallic solid state thermoelectric generators which also require no maintenance but are less efficient than Stirling engines and also degrade slowly over time.
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