Radioactive energy as an alternative energy source?

  1. I am new to this forum, and I am not a physics major. I simply had a thought earlier today of why radioactive energy, in particular gamma rays, can't be converted into usable energy. If some gamma rays are emitted as photons, couldn't one simply use solar panels as a means of capturing the energy? If this is a ridiculous question I'm sorry, I was curious of why or why not this can be done.
     
  2. jcsd
  3. Where would you get those gamma rays? There's no abundant source of gamma rays on the planet.

    It's possible to produce small quantities of radioactive elements and package them into mini-batteries. It's expensive and there are obvious safety issues, but you get a reliable long-lasting energy source. They are usually used for spacecraft. Voyager-1 deep space probe is powered by one of those, it was launched in 1977 and it's still working.
     
  4. malawi_glenn

    malawi_glenn 4,727
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    voyager had effience of around 5% or something like that ;-)
     
  5. RTG's (like the one used on Voyager I and II, Pioneer 12, etc.) DO use a radioactive source for energy conversion. In this case, the gamma/beta/alpha kinetic energy is coverted to heat (by many many collisions with a shield or the source itself), and this heat is used to run a thermionic diode.

    The trouble with this method is that you need a LOT of a radionuclide to make it work...something which makes it very dangerous for use around living things. So, these RTG's are rather dangerous, and expensive to make (unless you make it from reprocessed nuclear waste, then it's slightly less expensive than making the isotope in a research reactor).

    That being said, geothermal energy is a manifestation of natural radioactive decay. So, if you want to, you could claim your geothermal plant was really an elegant natural RTG system :)
     
  6. One could try to isolate caesium-137 from nuclear waste. Pure Cs-137 would probably be red hot due to the radioactive decay, so you can imagine using it as a heat source. You could think of using it in powerplants in the steam reheating stage, or simply to produce hot water.

    After a few decades, the power will diminish and then you can recycle the material.
     
  7. chemisttree

    chemisttree 3,723
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    In a betavoltaic battery, a beta emitter (beta particle is an electron) is used to generate free electrons. The primary beta particles strike a target of suitable design and a shower of secondary, lower energy beta particles are generated. These secondary beta particles are directed to a conductor and there you have it... a battery powered by radionuclides. I have seen carbon-14 tried (with mixed results).
     
    Last edited: Sep 25, 2008
  8. mgb_phys

    mgb_phys 8,952
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    You could also burn diamonds!
    Ceasium isn't cheap and extracting it from waste would be even more expensive.

    The cheapest way of using radiation as an energy source is to drill down into some granite, pump in cold water and use the hot water that comes out.
     
  9. vanesch

    vanesch 6,236
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    It would even be better if we could control the "radioactive reaction": that is, by doing things which makes the stuff react or not. For instance, there are substances that undergo kind of radioactive processes which give off a lot of energy when they get irradiated with neutrons. Of course, the problem is to make the neutrons, but it happens that the same reaction also produces neutrons. So hey, if we do it clever, we could use those neutrons to irradiate the stuff itself, then the thing would be giving off energy by itself, and we can stop it when we remove enough neutrons... I'm going to patent this invention !

    Uh, the stuff already exists, it is a nuclear power plant...
     
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