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Would it be feasible to dump nuclear waste inside active volcano's

  1. Jun 3, 2008 #1
    Nuclear waste is just a product of nuclear processes . In addition, nuclear waste would could in no way find a path back up to the surface since the nuclear waste would be burned up by the magna. It also seems more economically feasible to just dump all waste in addition to nuclear waste inside an active volcano rather than storing wastes inside mountains inside Nevada. There would be no radioactive contanimation generated if nuclear waste is immersed in magna. To me that seems more economically feasible than spending billions of dollars transporting trash on Space shuttles to the sun.
     
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  3. Jun 3, 2008 #2
    The heat of a volcano could break down the molecular bonds between atoms, but not the nuclear bonds inside of atoms. These nuclei would be unaffected by the volcano. What's worse, some of these nuclei would be emited into the atmosphere by the heat.
     
  4. Jun 3, 2008 #3
    how hot would the volcano have to be to break up the nuclear bonds inside of atoms? Why would it be necessary to breakup the nuclear bonds inside the atoms?
     
  5. Jun 3, 2008 #4
    Because that is where all the radioactivity is. I don't think any chemical fire could ever be hot enough to break down nuclei.
     
  6. Jun 3, 2008 #5

    D H

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    The undesirable byproducts of a coal burning power plant are nasty chemical compounds. The undesirable byproducts of a nuclear power plant are nasty radioactive isotopes. The heat of the magma will not change these nasty radioactive isotopes.

    We don't do that with any rockets, and particularly not with the Space Shuttles. The shuttles only go up to low Earth orbit. They do not have enough energy to go beyond that. If we were to dump our waste in space, it would be a lot cheaper to send it out of the solar system rather than into the Sun. It takes a lot of energy to send something into the Sun from Earth orbit, a lot more energy than it takes to make something completely escape the solar system.
     
  7. Jun 3, 2008 #6

    Astronuc

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    As jimmysnyder indicated that magma (~3000 K - liquid rock) can only break chemical bonds between atoms, which does nothing to the radioactivity which is a nuclear property. Fusion temperatures (billions K (MeV range)), or nuclear reactions would be required to modify nuclei.

    Spent fuel contains most Zr-alloys, stainless steels, and fission products and transmuted fuel (transuranics) in mostly oxide form with some metallic inclusions. There are also gaseous fission products, isotopes of Xe, Kr, and volatiles like I, Br, Cs, which could escape the magma.

    Then if the magma flows, or the volcano blows, that material would be dispersed in the atmosphere.


    The shuttle is designed for low earth orbit (LEO), so it would never be used to haul radwaste to the sun. Besides, the solar wind and radiation would exert a substantial force against any object being fired at the sun, not to mention the high temperatures caused by the heat flux from the sun.
     
  8. Jun 3, 2008 #7

    Kurdt

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    Would it be better to reprocess the waste Astro?
     
  9. Jun 3, 2008 #8
    I agree with you ; I forgot that it usually require temperatures to be around billions of degrees to break apart nuclear bonds. There is probably no guarantee that the nuclear bonds of the nuclear waste would be broken up in a controlled fashion.

    However, I don't understand why elemental products of the nuclear waste would escape from the volcano. About the proposal to transport waste to the sun, wouldn't the trash start to burn as it approaches the solar wind of the sun? The surface of the wind is about 6500 K degrees and that is a high enough temperature to burned non-nuclear waste. Are you saying the solar wind acts like a sling shots and reverses the direction of an object that is heading towards it?

    Your saying the solar wind has a stronger affect on whether or not objects will travel into the sun than the sun's gravitational field?
     
  10. Jun 3, 2008 #9

    matthyaouw

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    Volcanoes are pretty damn good at dispersing their contents over wide areas. You might as well put the stuff in crop dusters...
     
  11. Jun 3, 2008 #10
    One way of altering nuclei is to bombard them with slow moving neutrons. I think there is a contraption that produces them relatively cheaply. If there are nuclear waste materials that could be rendered harmless by adding a neutron to their nucleus, then perhaps this should be done. Astronuc, are there nuclear waste products that would benefit from such treatment? I take it U235 is not one of them.
     
  12. Jun 3, 2008 #11
    Not exactly: there IS an ironclad guarantee that magma won't break nuclear bonds at all. Fission does not occur in volcanos.

    The thing about active volcanos is that they spew material *out*, often under very high pressure. Dumping nuclear waste into an active volcano would have the same effect as pulverizing it and then spraying it into the atmosphere. Which is to say that it's pretty much the worst thing you could possibly do with nuclear waste.
     
  13. Jun 3, 2008 #12
    I think there's a lot hidden in the word "relatively" here. It can be cheap to produce very small quantities of neutrons, but to get enough to process substantial quantities of nuclear waste, you need to use either a nuclear reactor or high-power particle accelerator, neither of which I would call cheap, and both of which beg the question of whether you'd actually be processing more waste than you're producing.

    That said, neutron irradiation is what makes breeder reactors work, and they're probably a better way to manage nuclear waste than any other processing/storage/disposal scheme I've yet heard of.
     
  14. Jun 3, 2008 #13
    This is the gizmo I was thinking of. The inventor made exaggerated claims about what it could do. None-the-less, it has found commercial use as a source of neutrons.

    Fusor

    But just tossing a neutron into a nucleus doesn't necessarily improve matters. Are there waste products that can be treated to good effect in this manner?
     
  15. Jun 3, 2008 #14

    Astronuc

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    Neutron sources like Fusors and neutron generators produce low levels of neutrons which are fine for neutron radiography, but wouldn't do a lot for transmutation.


    The transuranics, e.g. isotopes of Pu, Cm, Am could be transmuted, in special fast reactors or accelerator driven systems. But the ADS concept requires a lot of energy, which gets lost in the scattering of the proton beam and spallation reactions.


    Anyway, reprocessing and recycling makes the most sense - technically - but then there is the political issue of diversion of Pu-239 and proliferation. :rolleyes:


    Reprocessing and recycling is the subject of another thread.


    The issue with magma is that the fission products represent a spectrum of chemical forms from noble gases, to alkali and alkaline earth elements, halides, and a variety of transition metals and non-metals. Gases certainly won't stay put in the magma, especially noble gases, and volatiles likely won't either. Elements like Cs have low melting points, so they probably won't stay put. Volcanoes with accessible magma may not remain stable, and if they erupt and the magma overflows, then one has a dispersion problem if the magma contains disolved radionuclides. Remember Krakatoa in 1883! http://en.wikipedia.org/wiki/Krakatoa

    The idea of high level waste (HLW) is to entrain/entrap the radionuclides in a geologically stable structure (repository) for millions of years, or 100 kyr, or 10's of half-lives so that they stay put while decay to stable (non-radioactive) isotopes.


    One of problem isotopes is actually Np-237 which comes the decay of U-237. Np-237 has a long half-life of ~ 2.14 million years, and there is a fair amount of it.

    Chart of nuclides - http://www.nndc.bnl.gov/chart/
     
    Last edited: Jun 3, 2008
  16. Jun 3, 2008 #15

    vanesch

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    As in the other thread on transmutation, it is maybe a good idea to point out that transmutation and reprocessing and all that only play on the actinide component of the waste, which is the relatively low activity but long life time part of the waste. The high activity - short time (a few hundred years) part of the waste, the thing that makes that it is hot and dangerously active, are the fission products which are NOT transmutable, simply because it is a complicated soup of very different elements, as Astro pointed out.

    Undifferentiated irradiation of that mixture will make things on average even worse, because most fission products are already too neutron-rich (and are hence beta-emitters most of the time). So adding neutrons is very often not going to help.
    With actinides, it can help, because we can induce their fission (so that they become fission products) with fast neutrons.
     
  17. Jun 4, 2008 #16

    Astronuc

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    It did occur to me this morning that there was/is a process known as Synroc, in which calcined and vitrified HLW is blended with compounds similar to those found in geologically stable minerals.

    http://www.world-nuclear.org/info/inf58.html


    If one could find a magma of similar characteristics, it would be interesting to develop a process to blend HLW into the magma (in a closed and well-controlled process), which could then be placed in a repository.
     
  18. Jun 5, 2008 #17
    The heat in a volcano is not sufficient to change atomic nuclei. Radioactives will remain radioactive.

    Volcanos are places that are spewing OUT materials from within the earth. The heat would vaporize radioactive materials to be dispersed in the atmosphere. Lava and mudflows would spread the radioactive materials for miles around the volcano. And heaven help us all if there is a violent eruption where the mountain explodes - it would send radioactive fallout over a significant portion of the globe.

    The best place to put radioactives is probably in a subduction trench in the ocean floor where they will be covered before the containers are corroded through. Pick a point on a trench where it is farthest from a volcano or other upwelling to ensure it spends the maximum amount of time sequestered away.

    Yes, sending radioactive waste into the sun is one way to dispose of it. And even if it vaporizes and is blow off in the solar wind before it gets there, it will be dispersed so that we will receive a very negligible amount, if ever.

    The problem with off-planet disposal is the same as our efforts to get off the planet in the first place. This damn gravity well requires a huge amount of energy to get out of.
     
  19. Jun 9, 2008 #18
     
    Last edited: Jun 9, 2008
  20. Jun 22, 2008 #19
    I guess I am surprised at that ! I thought the Earth was orbiting the Sun in an ellipse constrained by a gravity potential well mostly determined by the sun mass.

    The energy to accelerate a mass to escape Earth gravity in a direction that will wander between the planetary and Sun masses to eventually leave the Solar system is surely more than to choose a direction where the mass will pass the equilibrium point and spiral into the Sun. I have not done the sums (yet), but this can be seen a deliberately missed slingshot.

    The heavy Cassini spacecraft which eventually launched in 1997 with insufficient rocketry to take the more direct intersection approach, was looped around Venus a couple of times, then back past Earth, then took a further shove from Jupiter to finally make it to out to Saturn. I am thinking that a slight change in direction past Venus would have dropped it right into Sol. How could dropping into the Sun involve more energy than effecting a difficult escape, even with the help of contriving a tow from passing planets?
     
  21. Jun 22, 2008 #20

    D H

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    Consider the case of directing a vehicle in a circular orbit toward the Sun versus placing a vehicle on a solar system escape trajectory. A 41.4% increase in orbital velocity will place the vehicle on an escape trajectory. On the other hand, if you want to make the vehicle dive straight toward the center of the Sun you will have to make the vehicle cancel all of its orbital velocity. It will always cost more to cancel 100% of the vehicle's orbital velocity and make it dive Sunward than to add a mere 41% and place it on an escape trajectory.

    Completely canceling the velocity is going a bit overboard. All that is needed is to place the vehicle on an orbit whose perihelion is inside. This means there does exist some distance out from the Sun inside of which it less delta-v is needed to make the vehicle dive into the Sun than to escape the solar system. This critical orbital radius is less than 2.414 solar radii. Even from Mercury's orbit it is cheaper to place a vehicle on a solar system escape trajectory than a sun-diving trajectory.
    Things in orbit do not spiral into the Sun by themselves. Unless the vehicle makes a very close encounter with a planet, the planets will merely perturb the vehicle's orbit and will not change the vehicle's orbital energy. So, what about a gravitational slingshot? The only planet that makes sense in this regard is Venus. I already showed how it costs more to make a vehicle in a circular orbit about the Sun at Venus orbital radius dive into the Sun than escape the solar system. A vehicle on an Earth-Venus trajectory will have a speed greater than that of Venus' orbital velocity when it intercepts Venus. It will take even more energy than the circular case to make the vehicle dive Sunward than it will take to make the vehicle escape the solar system.
     
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