micro nuclear reactors

Discussion in 'Architecture & Engineering' started by orcot, Feb 13, 2011.

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  1. orcot Valued Senior Member

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    http://www.eoearth.org/article/Small_nuclear_power_reactors

    are these designs for real?
    Will it be possible to build a nuclear reactor only 2.5 m long that can produce 50MW electrical energy?
    Will this be the next power source for planes,trains and boats?
    And if so what are the limits for the seize of a nuclear reactor?
     
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  3. fedr808 1100101 Valued Senior Member

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    it would probably be quite heavy but thats doable. And by having farms of these it could produce vast amounts of energy. Instead of having one big honking reactor have a bunch of mini me's.
     
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  5. orcot Valued Senior Member

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    yeah it probably will be heavy however a 2.5m cilinder with a radius of 0.6meters only has a volume of 2.83m³ if you take a heavy element like uranium that comes out at 5500kg/m³ you have a maximum weight of 15 565kg and it's well it's not going to be a massive chunck so it can only weight less. And let's compate it with a boeing 747 (plane) that can carry up to 229 980l of kerosine with a weight of 0.817kg/l that comes to a total weight of 187 893kg meaning the reactor would weight more then 10 times less.
    (I'm not that sure how much watt a boeing would need to lift of the ground but 50 megawatt sounds like a lot)
     
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  7. fedr808 1100101 Valued Senior Member

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    And that is before taking in the efficiency of an electrical motor vs. a turbofan engine.

    It would mean less maintenance time and less time necessary to train mechanics in how to maintain them.

    But the risk of a plane crash could be dangerous for such a reactor. But I suppose that considering the necessary shielding it shouldn't be impossible to make it into a pseudo black box sort of thing.
     
  8. Sarkus Hippomonstrosesquippedalo phobe Valued Senior Member

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    A number of military vessels are already nuclear powered.

    As for aircraft... a boeing 747 generates about 140 MWatt of power at full thrust, if I recall. Of that order of magnitude, anyway.
    A typical aircraft-carrier is around 200 MW.
     
  9. orcot Valued Senior Member

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    well your right on the carrier no doubt
    and wow your also right on the boeing.
    That's hard to believe and it's not at full thrust but at average consumption.


    But still those micro reactors will they have a bright future
     
  10. Stoniphi obscurely fossiliferous Valued Senior Member

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    Yeah, especially when they start putting them in plasma rockets to go to the planets. I am most anticipatory.

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  11. orcot Valued Senior Member

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    Yes but like sarkus said a boeing allready needs 140 Megawatt a saturn 5 for comparison needs 190 Giga watt.

    That is by the way more then 10 times the average power consumtion of norway (in 1998).

    also spaceplanes won't really bring the costs of launches down.

    But I imagen ones you reach orbit you could use the reactior for a VASIMR engine
     
  12. kmguru Staff Member

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    Last I heard, Toshiba is designing a 50-MW sealed system that will last 50 years. Add 4 of those, you have a propulsion system for the container ships. I prefer a Thorium based design that would be Ultra Safe.
     
  13. ULTRA Realistically Surreal Registered Senior Member

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    Nuclear submarines have traditionally had very small reactors, about the size of a washing-machine. Pretty neat, compact units.
     
  14. orcot Valued Senior Member

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    the size of a washing machine I could be wrong but that seems to small?
    If they could really make one this small it wouldn't make sence to send those hughe solar panels up to the ISS
     
  15. ULTRA Realistically Surreal Registered Senior Member

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    I think it would be a very heavy piece of kit to launch and install at the ISS. It also uses a lot of water to drive turbines which would also all have to be sent up there at huge cost. It also requires constant monitoring, and they aren't 100% reliable. Some satellites have been given nuclear reactors that use thermocouples to turn heat into power. There are issues with these falling back to Earth though.
     
  16. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    Russia made quite a few fission reactors for satellites. They had barely sub-critical fissile material surrounded by graphite vanes (similar to venetian blinds). When the vanes were open, not enough neutrons were generated to continue the fission, as most escaped through the open vanes, and the reaction stopped. When the vanes were closed, enough were reflected back by the carbon nuclei to promote the reaction at full tilt. The reaction could then be controlled by partially opening or closing the vanes.

    They are now boosted into high orbit which should keep them from falling back to Earth for a few centuries. One of them fell back prematurely (not sent to higher orbit properly) and covered Canada with radioactive fission product (and unfissioned fissile material), which Canada cleaned up and billed Russia for the clean-up job. (Google on 'Cosmos 954')
     
    Last edited: Mar 8, 2011
  17. kmguru Staff Member

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  18. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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  19. billvon Valued Senior Member

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    Well, it's already a power source for boats. Would be a little heavy for airplanes. It would be ideal for small communities, though; Galena, Alaska is considering putting one in for their (inaccessible) town' s power needs. That gives them both electric power and waste heat, which they would surely appreciate.
     
  20. X-Man2 We're under no illusions. Registered Senior Member

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    For small communities,lets take it farther and have these minis powering our housing additions,schools,hospitals,small towns,farms etc.

    Or the ultimate,each home have it's own suitcase sized power unit.We should litter the Country with these and then take down the ugly electrical lines,poles and towers.

    Are we game?
     
  21. orcot Valued Senior Member

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    yeah if you read the new today placing them everywhere wouldn't be that safe probably still anybody any idea at what tempratures a micro nuclear reactor would work (I've read they would have to cool down for up to a year)
     
  22. YellowDemon Registered Senior Member

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    Huge ships can consider this. Weight isn't an issue for them neither is safety
     
  23. cosmictraveler Be kind to yourself always. Valued Senior Member

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    "What Are RTGs?

    RTGs are lightweight, compact spacecraft power systems that are highly reliable. RTGs are not nuclear reactors and have no moving parts. They use neither fission nor fusion processes to produce energy. Instead, they provide power through the natural radioactive decay of plutonium (mostly Pu-238, a non-weaponsgrade isotope). The heat generated by this natural process is changed into electricity by solid-state thermoelectric converters. RTGs enable spacecraft to operate at significant distances from the Sun or in other areas where solar power systems would not be feasible. In this context, they remain unmatched for power output, reliability and durability.
     
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