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As CO2-GWD, how does nuclear compares to natural gas and oil?

  1. Nov 22, 2008 #1
    As a CO2-global warming denier (GWD), how nuclear power generation compare to natural gas and oil carbon fuels, in start up costs, long term costs, pollution, operating costs?

    Is there any reason natural gas and oil fossil fuels can not meet projected energy needs, besides the allegation of CO2-GW connection?

    (I'm aware of other fossil fuel, coal, releasing dangerous pollution, sulfates and even trace radioactive material)

    My own position is to continue to use and build clean burning natural gas and oil power plants until maybe in 100-150 years nuclear fusion (or IFR type designs) become affordable, and deal with excess CO2 if CO2 does indeed cause GW and not say solar sunspot cycles (say by seeding the ocean with iron).
     
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  3. Nov 22, 2008 #2

    vanesch

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  4. Nov 22, 2008 #3
    That's a pretty detailed and complicated list you have there.

    Either in this thread or a new thread, how does once through nuclear plants compare in cost to breeder-IFR type reactors, factoring both cost of storing nuclear waste (in once-through cycles) as opposed to teh design of a more complicated IFR type design (with on-site reprocessing)
     
  5. Nov 22, 2008 #4

    vanesch

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    I don't know the answer to that, and probably there are estimates around which I don't know about, but I would think that most of it is guesswork, for the simple reason that nor the storage of waste in deep geological repositories nor IFR-type reactors + reprocessing are yet up and running practically and are beyond the stage of prototyping. As such, I would venture to say that nobody can really know how much this costs really. That said, even a breeder reactor needs a repository ; only the requirements of the containment time of the repository are shorter. I guess the cost will also depend a lot on the red tape one will add to these things.

    For instance, if you allow to dump the stuff in the ocean, the cost of the waste management goes down drastically :biggrin:
     
  6. Nov 22, 2008 #5

    Morbius

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    ensabeh6,

    The original Argonne National Lab design for the IFR INCLUDED on-site reprocessing.

    This was demonstrated in the IFR prototype - which was a modified EBR-II.

    The EBR-II had on-site reprocessing cells - called the Hot Fuel Examination Facility - South.

    This had a "donut-shaped" hot cell with access to the fuel from either the inner or outer radius of
    the cell. See floor plan starting with Figure 1.

    http://www.osti.gov/energycitations/servlets/purl/5497065-cuYYW4/5497065.PDF

    Dr. Gregory Greenman
    Physicist
     
  7. Nov 22, 2008 #6
    Thanks for replying.

    Is there a reason that all proposed new nuclear plants, both in the US and in the world aren't being built as "breeder" with on-site reprocessing? Without specific numbers, I do not know the relative costs of designing on-site reprocessing versus once-through then storage. Is any on-site reprocessing, breeder reactor either in commercial operation or planned to being built anywhere in the world (say France or Japan or Uk or Korea?)
     
  8. Nov 23, 2008 #7

    vanesch

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    In nuclear technology, one advances slowly, and there's a long way between prototyping and commercial exploitation - partly also due to extremely conservative regulatory bodies.

    The current reactors are mainly PWR and BWR, thermal water reactors. There are other types too, but they all have a very long history, and a lot of practical experience. These reactors are what one calls "thermal reactors", not because they generate thermal energy, but because they work with "thermalized" or slow neutrons. It is a physical property of the nuclear interactions that the breeding one can obtain (the conversion of "inert" U-238, the bulk of the natural uranium - 99.3% - into burnable plutonium), that is, the amount of "bred fuel" over "used fuel" is less than one ; for a water reactor this is even only 60%. As such, with thermal reactors it is not possible to use the bulk of the U-238 as fuel through breeding: we throw away about 99% of the natural uranium with water reactors (95% of the enriched uranium, and all the depleted uranium). That's the "once through" cycle.

    It is *evident* that breeders would be *far more* efficient with uranium: about a factor 100 ! Now, in order to use breeders, one needs from time to time to separate the real waste (the fission products) from the fuel/U-238 mixture, and that separation is called reprocessing. One also needs to have enough plutonium to start up a breeder, and that is also obtained by reprocessing spend fuel. Also, reprocessing has the advantage of ONLY putting in the waste, the real waste: the fission products: so it reduces the VOLUME of the waste (but not its activity of course, apart from the plutonium which is now taken out as fuel).

    Now, breeder reactors are somewhat more sophisticated than water reactors, as they cannot have cooling water in their core, but things like liquid sodium or so, but these are not such difficult problems, and have been solved in the past. There have been several attempts to have a prototype commercial breeder reactor. There was of course the IFR, but in Europe there have been Superphenix in France, and Kalkar in Germany. Both have been shot down for essentially political reasons (anti-nuclear movement and Greens don't want any improvement in nuclear technology). Of course, there is not much working experience with breeders: that will only come when we will build and use them. That means that one is a bit less sure about their safety and so on - although this doesn't mean that they are objectively less safe: we simply have less data about it. There is one breeder reactor which has been working for 35 years: Phenix in France. It's fuel has been reprocessed already a few times. It is a relatively small reactor of 250 MW e.
    There are also a few breeder projects in Japan, but I don't know much about them.

    In France, and in the UK, there are now thermal reactors, and a part of their spend fuel is reprocessed in two large reprocessing plants: one in La Hague (F) and one in Sellafield (UK). But without breeders, one cannot really do much with this reprocessed stuff. Yes, one can use the extracted plutonium to re-use it once more in a thermal reactor, making MOX fuel. But that doesn't do much in the overall uranium economy. In fact, as long as one is working only with pure thermal reactors, reprocessing doesn't make much sense - only a little bit. The reprocessing serves essentially to put aside material to be used in breeders. It is our fuel pot for the future. It also conditions waste in a more compact way (vitrified waste instead of spend fuel elements).

    The reprocessing in France and the UK is of the classical PUREX style, not the pyroprocessing which is proposed in the IFR, which is far more advanced. On the other hand, there is a lot of industrial experience with it now.

    There has been a lot of political opposition to reprocessing and breeders, officially for proliferation reasons, although when you look at it, these reasons seem to be somewhat far-fetched although not devoid of truth. That said, the pyro-processing of the IFR was much more proliferation resistant.

    I don't see why in the long run, a breeder must be much more expensive than a thermal reactor. But in the beginning, of course it will be: it is a technology which will still need evolution, development, and gathering of experience.

    But for the moment there is a much simpler reason why we don't have breeders: natural uranium is still cheap and abundant. With existing technology, no risks of new developments etc... it is much more interesting for a utility to build a classical water reactor than to adventure in new types, with a lot of political and red tape resistance, and inevitably the costs of new developments. Fuel is a small fraction of the cost of nuclear power, and as long as there is no genuine economical incentive, it is totally understandable that one isn't going to push breeders any time soon from within the private sector.
     
  9. Nov 23, 2008 #8

    Morbius

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    vanesch,

    VERY GOOD summary.

    Although as you state; there are technical and experience hurdles as with any new technology -
    however, they can be dealt with and worked through; again as with any new technology - there
    are no technical "show stoppers".

    You identify the "thorniest" problem above; the POLITICAL problem. The politicians associate breeders
    and plutonium inextricably with nuclear weapons proliferation - even though that is not necessarily the
    case, as per the IFR:

    http://www.pbs.org/wgbh/pages/frontline/shows/reaction/interviews/till.html

    Q: The argument most put on the Senate floor was that the IFR increases the risks of proliferation.

    A: Yes. Well, it doesn't. As simply as that. There's no technical reason why one would make that
    argument. In order to produce weapons, you have to produce pure plutonium. The IFR process will not do
    that. The only possible argument that would hold any water whatsoever was that when showing people that
    plutonium is not the demon substance that it's been advertised as being, that, in fact, it's quite a workaday
    material, that in some way or other, the familiarity of it could be used to say that it doesn't hold the terrors
    that it's supposed to hold, and so, perhaps, more tempting in some way for someone to try to misuse it.
    But I mean, that's a far-out kind of argument, it seems to me, compared to the unquestioned benefits from
    simply using this stuff to produce energy.

    Science is "self-correcting". When an Einstein comes along and shows us that we don't have the
    complete story; science corrects its stance. We realize that Newton was correct only in the low
    velocity limit - but that the correct description is really Einstein's.

    With politicians; once they get an idea or association in their heads; it's virtually impossible to disabuse
    them of the idea; evern when you can demonstrably show that they are 100% wrong.

    Dr. Gregory Greenman
    Physicist
     
    Last edited: Nov 24, 2008
  10. Nov 24, 2008 #9
    Ok, thanks. You answered my question that it is cheaper to use natural uranium in a once-through cycle and store it, with current technology, then on-site reprocessing.
     
  11. Nov 24, 2008 #10

    vanesch

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    Well, yes and no. Today, for sure, simply because that's the way the infrastructure is now. But in the long term, this is far from evident. The reason is that the once-through cycle with thermal reactors (it simply doesn't make sense with fast reactors...) ALSO needs an expensive processing: the enrichment of uranium. It is not clear to me whether an on-site chemical reprocessing (once the infrastructure is there) must be much more expensive than an enrichment factory. I would guess the opposite, honestly. Also, with on-site reprocessing, we don't need uranium mining and refining anymore (until that big pile of actual spend fuel is burned, which will last for a thousand years or so).

    BTW, concerning proliferation, look at what has proliferated most in the past: it is not fuel reprocessing, it is enrichment. Our famous Khan spied the enrichment technology of URENCO to help Pakistan make its bomb, Iran is trying to build an enrichment facility, and (although it was probably bogus) one of the arguments for the Iraq war was those aluminium cylinders for centrifuges. So if we stop the enrichment, we cut off the *proven* path to proliferation. Not that it matters in a country like the US of course.
     
  12. Nov 25, 2008 #11
    Personally, I do favor building such an infrastructure. Is there any currently existing technology that is sufficiently similar to fuel reprocessing that it can give a model for engineering?
     
  13. Nov 25, 2008 #12

    vanesch

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    I'm not sure I understand your question. Traditional (PUREX) reprocessing has tens and tens of years of industrial use experience. It is a working technology.

    Pyroprocessing is demonstrated on smaller scales. There has not yet been, to my knowledge, an industrial large-scale demonstation of pyroprocessing, but there don't seem to be any showstoppers. It is a matter of deciding to build a few prototypes.
     
  14. Nov 25, 2008 #13
    My question was simply whether the Pyroprocessing used for nuclear fuel reprocessing could be developed commericially and on a large scale for some other commercial purpose, and once economies of scale reached, then incorporated in a more advance breeder-reprocessing design.
     
  15. Nov 25, 2008 #14

    Morbius

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    ensabeh6,

    The basic technology is commercial - it's similar to the way one refines aluminum.

    However, it does need to be done remotely; which is unique to the nuclear application.

    That's why the commercial experience is going to be less applicable - you don't need to refine
    aluminum behind a shield.

    The best resource for information on this technology would be the experience of Argonne
    when they were operating a pilot plant.

    Dr. Gregory Greenman
    Physicist
     
  16. Nov 25, 2008 #15
    Remotely? As in using robots behind a shield? I know the cost of robotic technology follows the computer industry falling costs in both software and Moore's law.
    What does Argonne tell us about costs and engineering challenges btw?
     
  17. Nov 25, 2008 #16

    Morbius

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    ensabah6,

    More like humans using master-slave manipulators.

    http://en.wikipedia.org/wiki/Remote_manipulator

    In post #25 of this thread I linked to a report by Argonne that covers some of this -
    I don't know if it has costs / challenges.

    http://www.osti.gov/energycitations/servlets/purl/5497065-cuYYW4/5497065.PDF

    Dr. Gregory Greenman
    Physicist
     
  18. Nov 25, 2008 #17
    Thanks I find this interesting. I do hope to see new nuclear plants as a solution. Perhaps they will be built in India and China? BTW wikipedia states India is pursuing thorium due to India's natural abundance. How different is thorium?
     
  19. Nov 26, 2008 #18

    Morbius

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    ensabah6,

    Thorium doesn't have a fissile isotope; whereas Uranium does - U-235.

    However, the bulk of the Thorium is Th-232 which is a fertile isotope like the bulk of Uranium; U-238.

    When Th-232 captures a neutron - it transmutes to fissile U-233 just as the capture of a neutron
    by fertile U-238 transmutes it into fissile Pu-239.

    Dr. Gregory Greenman
    Physicist
     
  20. Nov 26, 2008 #19
    So they need to develop some kind of equivalent to a fast breeder, with the neutron capture?
     
  21. Nov 26, 2008 #20

    vanesch

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    Yes, but the nice thing about the Th-U conversion is that it can be done in thermal spectrum, so with reactors with a design which looks a lot like current reactors (for instance, using water).
     
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