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Power Science

Material Converts Radiation Into Electricity 146

Posted by kdawson from the don't-irradiate-me-bro dept.
holy_calamity writes "Nuclear powered space probes like Pioneer have 'nuclear batteries' that (very inefficiently) convert heat from decaying isotopes into electricity. US researchers think a new material that converts radiation directly into power instead could make nuclear batteries 20 times more efficient. (Unfortunately they will likely not be user-replaceable.) The material consists of gold, carbon nanotubes, and lithium hydride."
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Material Converts Radiation Into Electricity

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  • Carbon nanotubes (Score:5, Funny)

    by j00r0m4nc3r ( 959816 ) on Friday March 28, 2008 @11:15AM (#22894594)
    Is there anything they CAN'T do?

  • There could be a serious benefit (Score:5, Interesting)

    by Samalie ( 1016193 ) on Friday March 28, 2008 @11:16AM (#22894600)
    If this works, imagine being able to generate electricity not just from nuclear power plants themselves, but from the nuclear waste storage facility?

    I would think, assuming of course this proved as pratical in pratice vs theory, that this could dramatically reduce our dependance on fossil fuels. Assuming of course you could use the "pure" radiation of the waste into electricity.

    • Re:There could be a serious benefit (Score:5, Interesting)

      by asuffield ( 111848 ) <asuffield@suffields.me.uk> on Friday March 28, 2008 @11:25AM (#22894722)

      If this works, imagine being able to generate electricity not just from nuclear power plants themselves, but from the nuclear waste storage facility?


      To heck with that, and with batteries - imagine being able to generate electricity from nuclear power plants themselves, rather than using them to heat water, shove it through an inefficient turbine, and then let most of the energy evaporate off in a cooling tower. The steam turbine system is horrendously inefficient. Cutting all of that out of the loop would make nuclear power so hilariously efficient that nobody would care about the waste storage (we wouldn't need much of it anyway). It would also be far safer: a lot of the stuff in a current nuclear plant goes into managing the water moving through the reactor, which is all expensive, fragile equipment that gets mildly contaminated. Replacing all that junk with some electrical cabling would be a major breakthrough.

      • Re: (Score:1, Interesting)

        by DCGaymer ( 956987 )
        One word.....Chernobyl Could it be used on something like that I wonder?
        • Most of Chernobyl is no longer very radioactive. A new "coffin" lined with this would be an excellent replacement for the aged cracking one surrounding the destroyed reactor, though.

      • Waste...? (Score:5, Interesting)

        by Half-pint HAL ( 718102 ) on Friday March 28, 2008 @12:15PM (#22895440)

        Cutting all of that out of the loop would make nuclear power so hilariously efficient that nobody would care about the waste storage (we wouldn't need much of it anyway).

        Actually, you've missed an important point about nuclear waste. Nuclear waste is dangerous because it's still radioactive. However, it's useless because it's no longer fissile and hence can't be used in a nuclear power plant.

        This technology should be just as efficient with nuclear waste as with fissile materials. However, the problem with this technology is time. Fission releases a lot of energy very quickly, but most most common radioisotopes have very long half-lifes, releasing their radiation over thousands of years. (Anything with a short half-life will have "died" millenia ago.) The applications for this will be relatively low-power, long-term projects.

        HAL.

        • Re:Waste...? (Score:5, Informative)

          by BlueParrot ( 965239 ) on Friday March 28, 2008 @12:27PM (#22895642)

          However, it's useless because it's no longer fissile and hence can't be used in a nuclear power plant.


          Not true, spent fuel is discharged not because it is depleted of fissile material but because other elements generated in it absorb neutrons. If you remove those elements chemically the fuel can be re-used, and with some fast reactor designs you can even ensure that they produce the same amount of fissile material as they consume ( by converting U-238 into plutonium ). The end result is about 100 times better uranium utilization and nuclear waste which decays to uranium levels of radioactivity within 300 years or so.
          • Built any nuclear bombs lately have we???

            • Re:Waste...? (Score:5, Interesting)

              by BlueParrot ( 965239 ) on Friday March 28, 2008 @03:39PM (#22898576)
              No, but if I were to try I would use low-burnup thermal reactors on PUREX reprocessing rather than ultra high burnup fast breeders with full actinide recovery heavily spiked with transuranics that have high rates of spontaneous fission. Alternatively I'd go for highly enriched uranium.

              Seriously thou, modifying the reprocessing cycle for a fast breeder and then use the very low grade plutonium to produce a nuclear weapon would be so unpractical that it would probably be easier to just start a uranium based weapons program from scratch. Simply separating the plutonium from traces of very troublesome elements with high spontaneous fission rates ( think californium, einsteinium ... ) would require a reprocessing plant unlike anything ever constructed or proposed. Building a nuclear device out of the recovered plutonium ( which would have a much less suitable isotopic composition than traditional reactors ) would require groundbreaking research into nuclear weapon design, and probably a number of tests.

              At the end of the day the effort involved would likely surpass that needed to build a more traditional graphite moderated reactor and extract the plutonium from that. I.e, even if somebody was to give you the reprocessing plant for a fast breeder with actinide recycling, as well as the spent fuel, you would probably have an easier time trying to do it the old fashion way. In addition it is hardly as if a rogue nation with the necessary economics would not be capable of building a nuclear weapon anyway. The technology is more than 6 decades old.

        • Re:Waste...? (Score:5, Interesting)

          by SatanicPuppy ( 611928 ) * <Satanicpuppy@nosPAm.gmail.com> on Friday March 28, 2008 @02:32PM (#22897432) Journal
          BlueParrot is 100% correct; if we reprocessed our nuclear waste it would virtually eliminate our waste storage problems. The final product would be much less radioactive, and degrade much more quickly.

          The only reason it's not done is that re-enrichment produces large amounts of bomb-grade material, which could theoretically be stolen and used to make a nuke, as opposed to our normal waste which is pretty much useless.

          This is getting to be a poorer and poorer excuse as time goes on, as more and more unstable countries learn to do the bomb thing for themselves. All we're really doing is saddling ourselves with a nasty radioactive waste problem.
          • We also signed some treaties that limit the amount of "bomb-grade" material we can produce.
      • Another point to ponder is imagine if they could use this material in a way that there TECHNICALLY wouldn't be much waste from current planet designs until they master this technology enough to generate electricity solely from it and traditional planets are being phased out.

        While nuclear waste from current reactors is no longer good for creating the massive quantities of heat needed to run a steam turbine, the radiation levels stay extremely high for decades and the "waste" could be placed in a secondary, l
      • The article didn't discuss any absolute efficiency numbers. It only said the new tech was much more efficient than thermoelectric generators, whose efficiency is abysmal. There is no mention of having efficiency better or even comparable to a steam turbine.

        Steam turbines are mechanically complicated and smell of old tech but they are actually rather efficient. Large steam turbines have thermodynamic efficiency in the 90% range. I rather doubt this new nuclear photocell is anywhere close.

        • Re: (Score:3, Insightful)

          by asuffield ( 111848 )

          Large steam turbines have thermodynamic efficiency in the 90% range.

          That's the loss in the turbine itself - the number most favourable to the turbine manufacturer's marketing department. The main loss in a steam turbine system is in the required cooling/condensing apparatus that must accompany the turbine to close the cycle.

          Actual thermal efficiency for nuclear plants tends to be in the 5-30% range. The 40-year-old designs that comprise most plants in the US and western Europe are appalling; current designs

        • Steam turbines are mechanically complicated and smell of old tech but they are actually rather efficient. Large steam turbines have thermodynamic efficiency in the 90% range. I rather doubt this new nuclear photocell is anywhere close.

          Can you think of a reason this kind of technology can't be used in conjunction with a steam turbine? Modern nuclear reactors almost all work on basis of using radiation to heat up water, turning it into steam which then turns a turbine. But the water doesn't trap all of the ra

      • Re:There could be a serious benefit (Score:5, Interesting)

        by Thelasko ( 1196535 ) on Friday March 28, 2008 @02:50PM (#22897790) Journal

        The steam turbine system is horrendously inefficient.
        Compared to what? I have news for you. Steam Turbines are one of the most efficient engines we have. That's why we use them!

        The second law of thermodynamics says that no engine can be 100% efficient. The reason is, a 100% efficient engine would require an infinitely hot source of energy and infinitely cold surroundings, assuming there is no friction. Carnot, [wikipedia.org] says that the best we can hope for is more like 60-70% efficiency, and Rankine, [wikipedia.org] suggests that a more realistic number is somewhere between 40-50%. That "inefficient turbine" you speak of is 40% efficient in reality. That's pretty good considering the best we can hope for is 60-70%.

        I am not a nuclear physicist, but the laws of thermodynamics still apply. We can still only hope for 60-70% efficiency, but for various reasons we still won't be able to archive this. Now, instead of letting "most of the energy evaporate off the cooling tower" we will be radiating it to the surroundings instead. Fine for spacecraft, not fine here on Earth. Even though this technology sidesteps the creation of thermal energy it still must obey the laws of thermodynamics.

        • Re:There could be a serious benefit (Score:5, Interesting)

          by asuffield ( 111848 ) <asuffield@suffields.me.uk> on Friday March 28, 2008 @03:16PM (#22898212)

          Compared to what?


          Compared to the amount of energy wasted. Most of it is lost in the cooling towers that are needed to keep the cycle closed, the rest is lost in transfer from the core.

          Steam Turbines are one of the most efficient engines we have. That's why we use them!


          Yes. And guess what? The most efficient system we have is not very efficient at all. Also note that the main problem is not the turbine itself, but the system as a whole used to transfer energy from the nuclear core to the grid output.

          Carnot, says that the best we can hope for is more like 60-70% efficiency, and Rankine, suggests that a more realistic number is somewhere between 40-50%.


          Which is precisely why a system based on a new material like this, which does not involve the Carnot (or Rankine) cycle at all, would be hugely more efficient. The whole point is that heat transfer systems are not a good way to extract energy from a nuclear power plant, because of those intrinsic inefficiencies.
        • The Carnot cycle describes an ideal *heat* engine. As such, it only the most efficient way to convert heat to mechanical power.

          This is a different kind of engine. So, it is not held back by the same limits as the carnot cycle, but by other limits.
      • If you can name 5 technologies at power generation than a steam turbine, and also work on the same scale (Gigawatts) I could accept your horrendously inefficient claim. But from what I can recall from somewhere in my brain, modern steam turbines are 50-60% efficient while most other generators are in the 30-50% range. I could of course be wrong.
        • Perhaps you missed the article. We're talking about a new technology that works on a different principle, which happens to escape the fundamental efficiency limits of a heat-transfer cycle, and hence could potentially be developed into a far more efficient nuclear power generation method.

          And the actual thermal efficiency of a steam-cycle nuclear power plant is in the 5-30% range (with most of the ancient, 1960s reactors that you find in the US and western Europe coming in at the 5% end - new reactor designs

      • Re: (Score:2)

        by Rei ( 128717 )
        To heck with that, and with batteries - imagine being able to generate electricity from nuclear power plants themselves, rather than using them to heat water

        To heck with that, too. You did notice that the tech involves lots of gold, right? It's bremsstrahlung radiation from the collision with gold that causes the shower of electrons that is captured.

        Now, perhaps a *future* technology might use some other metal as the target. But this one would clearly be way too expensive to enclose a reactor or waste st
      • We've had the technology to go from heat (differential) to energy for quite some time, but I'm still betting there's no Seebeck chips wired in the cooling tower. My guess is you won't see any of this stuff near a nuclear power plant any time soon either.
    • That's the first thing I thought of when I read the article... You get double-use out of the nuclear materials:

      phase 1: generate power with standard fusion
      phase 2: take the waste to a secondary waste-to-energy facility
      phase 3: PROFIT!

      After all, we're currently just burying (or would like to) our waste since it will be "hot" (in a radioactivity sense if not a thermal sense) for a long, long time. Why not get that extra bang for the buck? We've got the waste anyway, so why not get a bit of benefit from it.

      In

    • If this works, imagine being able to generate electricity not just from nuclear power plants themselves, but from the nuclear waste storage facility?

      Let's consider that for a moment. Nuclear fission releases about 200 MeV per nucleus, while radioactive decay releases about 5MeV per nucleus( assuming alpha emission ). Thus even assuming 100% efficiency for this tech, and only 30% efficiency for existing reactors, fission gives you more than 13 times more energy than the radioactive decay, and this is assumin

      • Re: (Score:2)

        by drakaan ( 688386 )

        Thus even assuming 100% efficiency for this tech, and only 30% efficiency for existing reactors, fission gives you more than 13 times more energy than the radioactive decay, and this is assuming that you have enough time to wait for all nuclei to decay. In practice, because most of the alpha-emitters have half lives measured in thousands of years, the total amount of energy that could be generated by this tech per year would be thousands of times smaller than that from fission, so you're better of just buil

        • Beyond that, retrofitting existing reactors with auxiliary power generation stations that use what is now considered "spent" fuel would eventually supply as much power as the current reactors do, and they'd keep doing it for thousands of years with the same fuel (you'd have to do maintenance, of course).

          Let me put things into perspective for you. Sweden's current fleet of nuclear reactors provide 25% of it's energy demand. If operated for about 60 years they will produce enough spent fuel to fit in a 10m cu

        • What *I* want to know about is how effective this material is as a radiation shield. Something that can both protect you from radiation and generate electricity seems awfully handy.
          I'm guessing it's only slightly more effective as a radiation shield as it is at producing electricity. (i.e. radiation not turned into electricity passes through the material.) But I could be wrong.

        • Re: (Score:2)

          by amorsen ( 7485 )

          What *I* want to know about is how effective this material is as a radiation shield. Something that can both protect you from radiation and generate electricity seems awfully handy.

          The material consists of a layer of gold followed by some light stuff to catch the electrons. I bet the layer of gold would do >50% of the radiation shielding, so that should get you in the right ballpark. Gold is very good radiation shield, I can certainly recommend that we use that around our reactors instead of the concrete that is popular today.

      • Re: (Score:2)

        by Duhavid ( 677874 )
        One thing to factor into your thinking is that there is probably a lot more
        waste material sitting around than is active in cores of reactors. Also, I
        would think that that waste material would be producing at the lower figure,
        but for a much longer period of time.

        • Also, I
          would think that that waste material would be producing at the lower figure,
          but for a much longer period of time.

          Doesn't matter, you get 200 MeV per fission ,and about 5MeV per alpha decay, if those events happen instantaneously or over the course of millions of years make little difference, fissioning a nucleus simply emits more energy than radioactive decay. The amount of energy that can be extracted from a given number of nuclei when they fission is simply greater than the energy that can be extra

          • Re: (Score:2)

            by Duhavid ( 677874 )
            I don't see it as either / or.

            Yes, use fission, and reprocess the fuel to the extent possible, and work to
            increase reactor efficiency, but once that fuel is out of the reactor, why not
            *add* this new technique and continue to generate lower levels of electricity
            from that. Assuming it works, of course.

            During that same 60 year cycle, you will have, each year, one more core set
            to do something with. You are not going to get that 200 MeV from it, it is not
            in a reactor, why not go ahead and get that ( 5 * number
            • Because the fission products decay by beta emission, which generates about 1/2000 times the energy of fission, which means that if you do this at the back end will add a pathetic 0.05% to your energy output, and you could get the same effect by just using the heat from the radioactive decay for district heating or some other much easier to implement heat-conservation scheme.

    • If this works, imagine being able to generate electricity not just from nuclear power plants themselves, but from the nuclear waste storage facility?
      That's inspired. Using them to coat the interior of the core is obvious, but coating the interior of storage facilities with the stuff is just inspired.

      Combine that with current recycling and re-refining techniques and that's got to be a significant step forwards for nuclear energy.

  • Why is it... (Score:5, Funny)

    by narrowhouse ( 1949 ) on Friday March 28, 2008 @11:23AM (#22894682) Homepage
    that all these neat technologies depend on exotic materials? Just once I would like some really cool technology to be dependent on something cheaper and easy to obtain, while being ten times more efficient that the gold/lithium irradiated crystals it replaces.

    Today's news: hobo sweat and nail clippings mixed with Diet Coke and mentos == cold fusion.

    • Re:Why is it... (Score:5, Funny)

      by Anonymous Coward on Friday March 28, 2008 @11:52AM (#22895148)

      You think hobo sweat and nail clippings are easy to obtain? Trust me, chasing them and holding them down while you get the supplies is a lot more work than you expect. Unless we set up some sort of hobo farm, I don't see your plan being feasible.

    • Re: (Score:3, Informative)

      by pla ( 258480 )
      Why is it ... that all these neat technologies depend on exotic materials?

      Because most of our existing technology comes from adapting what we've observed occurring more-or-less naturally in the world around us, and we've already plucked all the low-hanging fruit.

      If you want to understand how to extract energy from hydrogen sulfide, you can study deep sea vent bacteria. If you want to understand how to directly convert radiation to electricity... Well, we don't know of anything that already does that,

      • Re: (Score:1)

        by Punko ( 784684 )
        if you want to understand how to directly convert radiation to electricity... Well, we don't know of anything that already does that, so if such a phenomenon exists (which seems reasonable),

        Photovoltaic cells convert radiation in to electricity. DIRECTLY. Of course, its only EM radiation that falls within a specific energy profile, and doesn't include alpha, or beta particles, but at least the certain range of gamma radiation is covered.

        • Re: (Score:1)

          by pla ( 258480 )
          Photovoltaic cells convert radiation in to electricity. DIRECTLY.

          Fair catch, I should have stated my point more specifically... But you know what I meant. :)

      • ...it makes sense to start with some of the most exotic substances we know of.

        I was with you right up to the end. I'd like to think the substances in question were chosen for the experiment because of their physical characteristics, and not JUST because they are exotic.

      • And that's why it's a good idea to research the bacteria/moulds etc which live in and near Chernobyl. Life 'finds' a way, and thanks to the random changes/evolution of the lifeforms there, some very interesting and potential mutations can have popped up there.

        We'll have to go look, though.
    • Clearly you've never heard of "youtube"

      In fact, there's an entire army of people who've figured out you can power an automobile entirely from plain water.
      They have videos and everything. It's totally amazing.

      What's really surprising is that the auto industry hasn't incorporated this amazing discovery into their new vehicles.

      • Re: (Score:2)

        by geekoid ( 135745 )
        haha, seriously You tube videos? Yes, that all the evidence we could need.

        The ater powered aoutomobile is a fraud. Or I should say, all studies of them have only found some fraudster at the heart.

        You're right, if they could make practical cars that are fueld by water the Auto industry would be all over it. It would litterally save the American autoindustry, as well as meen billion dollar bonuses. If not the US car companies, then any one of the other car companies. Hell If you could gat a car, prove it runs
    • Hear, hear! Years ago, Steve Martin proposed the ideal material to collect solar heat: Car seats.

    • Re: (Score:2)

      by brunes69 ( 86786 )
      But then hobos would be in such high demand you would never be able to find any when you wanted to watch a good fight.

      • Re: (Score:3, Funny)

        by wattrlz ( 1162603 )
        Sure you would. What do you think we'd do with them after they'd been harvested? Heck, you could have them fight over a grate and some sluices and collect the sweat that way...

    • Simply because we have been juggling petrochemicals around for decades and have found most of the useful things they can do already.

      Nanotechnology is developing as petrochemicals did decades ago. When substances are reduced to nanoscale particles, their properties change so drastically they might as well be new materials. This means that physicists are suddenly discovering thousands of new substances at once and want to see what they can do, just as chemists did with petrochemicals.

    • You did see the article on room-temperature superconductors [slashdot.org] last week, right? Hydrogen and silicon are among the most common elements on Earth. That may not meet your standards for neatness, though, since it requires high pressures.
    • Wool.

      Shave a sheep, cover yourself in the shavings. You'll stay warm, even if you get wet. How cool is that!?

    • Today's news: hobo sweat and nail clippings mixed with Diet Coke and mentos == cold fusion.
      Whoa, hobo nail clippings are made of Mentos?
      • Nothing worse than noticing the fail in your joke right after you hit submit. Nothing to see here. Move along.
  • Would be to use int he reactor of a Nuclear rocket to generate electricty during the coasting phase between planets. If you go further than Mars Solar panels just ain't gonna cut it.

  • article mentions use in fission reactor.

    when producing electricity,
    will it consume (remove waste) radiation
    or will it only use radiation ?
  • My first thought on seeing the headline was if a nuke went off, I'd have the choice of getting fried by radiation or electrocuted by the suit.

  • Shielding? (Score:3, Insightful)

    by Bombula ( 670389 ) on Friday March 28, 2008 @12:29PM (#22895700)
    Would this material make good radiation shileding? Seems like manned spaceflight could make use of a material that did double-duty as radiation shields and solar panels.
    • This device doesn't do anything novel when it comes to fundamental radiation interactions. What's doing most of the stopping of the radiation is the gold, since it's a dense and high atomic number material. The device's utility as a sheld, therefore, depends on the thickness of gold that incoming particles would have to penetrate on a typical path through the material. Even if space progams used gold for shielding--maybe they do, for some reason, instead of lead or uranium or steel or something--the thickne
    • I think the trouble with radiation in space is that the energies are so high. This stuff isn't a more effective shield than lead or water, I'd expect. The news is its ability to generate electricity in the process.

  • Hirsch-Meeks fusor? (Score:4, Interesting)

    by OglinTatas ( 710589 ) on Friday March 28, 2008 @01:52PM (#22896800)
    Might this material make the Hirsch-Meeks fusor [wikipedia.org] energy positive?
    Or are the unnamed "radioactive particles that slam into the gold" not neutrons?
    Is the energy recovery from this material, even 20 times better than thermoelectric materials, not nearly good enough to extract enough energy from the fusor?

  • Betavoltaics (Score:3, Informative)

    by denominateur ( 194939 ) on Friday March 28, 2008 @03:55PM (#22898780) Homepage
    I'm pretty sure the article is reffering to technology very similar to betavoltaic cells but with the twist of using gold as an electron source and some more strongly radioactive isotope as the energy source rather than using beta-decaying tritium directly. http://en.wikipedia.org/wiki/Betavoltaics [wikipedia.org]
  • How long before we can make them like mini zpms
  • I mean, we've had the International Space Station in orbit for quite a while now and it's been using this same technology... they're called "Solar Panels." They're function is almost exactly the same... they take radiation (though in a different wavelength) from the sun and convert it into electricity.

    Hey, my calculator also uses a similar technology.... oh, wait... so does does my car's battery maintainer. Wow... this technology catches on fast!

    Bill

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