# Miniature Nuclear Reactor Could Power Mars & Moon Colonies



## Runvardh (May 17, 2011)

I had put this into the ISTP section at one point, but thought it may make an interesting addition here.

Miniature Nuclear Reactor Could Power Mars & Moon Colonies | Manned Mission to Mars | Space Colonies | Space.com


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## General Lee (Oct 22, 2010)

One step closer.


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## absentminded (Dec 3, 2010)

Another reason I want to be a nuclear engineer.

I'm excited. :happy:


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## Runvardh (May 17, 2011)

Imagine being able to load them like batteries into a car.


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## General Lee (Oct 22, 2010)

Runvardh said:


> Imagine being able to load them like batteries into a car.


I would like to see how safe they would be first. Don't won't a mini nuclear meltdown during the rush hour.


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## Runvardh (May 17, 2011)

General Lee said:


> I would like to see how safe they would be first. Don't won't a mini nuclear meltdown during the rush hour.


Apparently it's small enough that it would loose heat pretty fast due to such a small core.


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## General Lee (Oct 22, 2010)

Runvardh said:


> Apparently it's small enough that it would loose heat pretty fast due to such a small core.


Reasonable.


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## MachinegunDojo (Dec 27, 2009)

http://www.ne.doe.gov/pdfFiles/FissionSurfacePowerSystem.pdf

The above may be a good read, I'm giving a good look over right now to see how it works exactly. So far it certainly doesn't seem to be something very portable just small enough to easily bring with you to setup once you are there. So you're not having one of these in your EV soon


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## RobynC (Jun 10, 2011)

I'd like to see manned space missions.


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## absent air (Dec 7, 2010)

Imagine starting a company that builds mini nuclear facilities, damn that would be an awesome adventure!


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## dalsgaard (Aug 14, 2010)

It probably won't be fission. We'll have fusion reactors before this shit becomes relevant, and there is plenty of He-3 deposits on the moon. Humans haven't moved their collective asses one iota since the moon-landing. By the time we finally get our act back together we'll be well into the next century.


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## Runvardh (May 17, 2011)

dalsgaard said:


> It probably won't be fission. We'll have fusion reactors before this shit becomes relevant, and there is plenty of He-3 deposits on the moon. Humans haven't moved their collective asses one iota since the moon-landing. By the time we finally get our act back together we'll be well into the next century.


Na, China should be on the Moon in the next 3-4 decades.


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## absentminded (Dec 3, 2010)

dalsgaard said:


> We'll have fusion reactors before this shit becomes relevant, and there is plenty of He-3 deposits on the moon.


You're assuming a break-through that may never happen.

Fusion is _incredibly_ hard and some of the most efficient methods are at around 25-50% efficiency. Couple that with the fact that people don't exactly give fusion research tons of funding or credibility, and you don't exactly have a high probability of anything happening any time soon.


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## dalsgaard (Aug 14, 2010)

absentminded said:


> You're assuming a break-through that may never happen.
> 
> Fusion is _incredibly_ hard and some of the most efficient methods are at around 25-50% efficiency.


You do realize that this is a really high efficiency rate, right? A lot of fossil fuel plants don't have an efficiency higher than around 30%.



> Couple that with the fact that people don't exactly give fusion research tons of funding or credibility, and you don't exactly have a high probability of anything happening any time soon.


One of the major problems surrounding fusion is that the materials within the reactor tend to degrade over time, because the lithium blankets inside the reaction vessel degrade due to neutron radiation. However, He-3 doesn't produce neutrons when it reacts with itself, which defeats a lot of the problems relating to fusion reactors. It would be a feasible material for fusion, but it is a very rare isotope. _On earth_, that is. On the moon it's far more prominent.


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## absentminded (Dec 3, 2010)

dalsgaard said:


> You do realize that this is a really high efficiency rate, right? A lot of fossil fuel plants don't have an efficiency higher than around 30%.


Sorry, I should have clarified. When one talks about efficiency in nuclear fusion, one generally means the amount of energy you get out divided by the amount of energy necessary to create the conditions for fusion to take place. It currently takes two to four times as much energy to initiate fusion as we get out of it.



> One of the major problems surrounding fusion is that the materials within the reactor tend to degrade over time, because the lithium blankets inside the reaction vessel degrade due to neutron radiation. However, He-3 doesn't produce neutrons when it reacts with itself, which defeats a lot of the problems relating to fusion reactors. It would be a feasible material for fusion, but it is a very rare isotope. _On earth_, that is. On the moon it's far more prominent.


True He-3 fusion doesn't produce neutrons, but He-3 + He-3 reactions are four(?) times as difficult to start as D + T reactions and even more difficult to keep ignited due to bremsstrahlung.

One other idea people have proposed is a two-stage plant, where the first stage is a Deuterium/Tritium fusion reactor and the second stage is a series of actinide rods or plates that undergoes fission as a result of the fusion reaction's waste neutrons.


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## dalsgaard (Aug 14, 2010)

absentminded said:


> Sorry, I should have clarified. When one talks about efficiency in nuclear fusion, one generally means the amount of energy you get out divided by the amount of energy necessary to create the conditions for fusion to take place. It currently takes two to four times as much energy to initiate fusion as we get out of it.


I understand, I just wanted to be sure we were on the same page. 



> True He-3 fusion doesn't produce neutrons, but He-3 + He-3 reactions are four(?) times as difficult to start as D + T reactions and even more difficult to keep ignited due to bremsstrahlung.


Yes, which is quite the challenge I admit. My original sentiment was more of a frustrated outburst at the fact that humanity's manned exploration hasn't progressed at all. When my father watched the moon landing live in 1969, he thought he would live to see a manned mission to Mars, or at least a colonization of space. While the ISS is awesome in its scope, and various probes like the viking lander, voyager, and the mars rovers are pretty exciting - well....



> One other idea people have proposed is a two-stage plant, where the first stage is a Deuterium/Tritium fusion reactor and the second stage is a series of actinide rods or plates that undergoes fission as a result of the fusion reaction's waste neutrons.


That also sounds pretty hard to control. Creating a stable fission reaction using plasma burning at millions of degrees.... You may be right that a hundred years isn't quite enough.

EDIT: Come to think of it, actinide rods doesn't sound feasible at all. Reaching a critical chain reaction with moderators in that sort of environment is one thing, preventing it from becoming over-critical and melting down is another. Do you know if they actively pursue this?


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## absentminded (Dec 3, 2010)

dalsgaard said:


> That also sounds pretty hard to control. Creating a stable fission reaction using plasma burning at millions of degrees.... You may be right that a hundred years isn't quite enough.
> 
> EDIT: Come to think of it, actinide rods doesn't sound feasible at all. Reaching a critical chain reaction with moderators in that sort of environment is one thing, preventing it from becoming over-critical and melting down is another. Do you know if they actively pursue this?


I do not know if they are actively pursuing it. Interestingly enough, it's a basically a thermonuclear warhead backwards.


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## dalsgaard (Aug 14, 2010)

absentminded said:


> I do not know if they are actively pursuing it. Interestingly enough, it's a basically a thermonuclear warhead backwards.


Except in warheads, we don't have to worry about overcritical chain-reactions. That's sort of the point of it all 

It sucks that it's fairly easy to release an enormous amount of energy at once. Just compress material fast enough, and it will go 'kaboom'. But a nuclear reactor is, in a way, just a controlled series of small nuclear explosions. Adding to all of that, we have neutrons that behave in a manner that is, by physical law, unpredictable. It astonishes me that we are even able to come close.


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## Runvardh (May 17, 2011)

dalsgaard said:


> However, He-3 ... it is a very rare isotope. _On earth_, that is. On the moon it's far more prominent.


And Saturn, IIRC.


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## MachinegunDojo (Dec 27, 2009)

I think by the time fusion becomes a reality we'll have perfected clean nuclear fission. IIRC We're pretty close as it is, just need to bring down the heavy costs. No nuclear waste will kill most problems with nuclear fission. Not to mention better materials to guard against natural disasters are quickly becoming better and better and just as necessary for potential nuclear fusion systems anyways. I'd imagine the costs needed for proper nuclear fusion research would be greater than building a clean nuclear reactor that can utilize current nuclear waste as a (secondary?) fuel. It's one thing to come up with a new method of producing energy but what about getting rid of the current waste build up?


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