Nuclear Energy

Discussion in 'Chemistry' started by lambogiggy, Jul 11, 2009.

  1. lambogiggy Lambo Giggy Registered Senior Member

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    Is nuclear energy a solution to an energy crisis?
    please feel free to elaborate on this topic i would really like to see what everyone has to say, thanks.

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  3. Xylene Valued Senior Member

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    The major problem with nuclear energy is dealing with the waste;

    A) storage--10-100,000 years in a geological formation that is not going to be compromised by earth movements or some other violent process during that length of time--extremely unlikely, so the burial has to be deep, and records have to be kept of the location of the deposit, and warnings have to be put up so people keep their distance.
    B) reprocessing of nuclear material so it can be reused.
    C) movement of waste and fissile materials; this presents all sorts of problems because of the possibility of accidents; saboutage; terrorists getting their hands on the material; loss of material because of human error, incompetence or theft (ie Murphy's Law, if it can go wrong, it will).

    Aternatives;

    1) Solar energy arrays in the world's major deserts:
    2) Biofuels generated from plant wastes (rather than specifically growing mass-plantation biofuel-destined crops, which disrupts existing ecosystems):
    3) Tidal energy, either with barrages across river mouths (allowing the tide to rise, then closing the barrier and trapping the water until the tide has fallen to a low enough level to give sufficient head of water for generation:
    4) Hydrpower resources, and microhydro (really small plants which will power a single property, and allow that family to remove themselves from the national power grid if they choose):
    5) Wind power turbines:
    6) Geothermal power, where available (such as Iceland and New Zealand)

    Hope this helps...

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  5. cosmictraveler Be kind to yourself always. Valued Senior Member

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    Using Breeder Reactors would be a better way to use nuclear energy, very little waste , less than 1 percent , compaired to over 10 percent using conventional reactors.


    Reprocessing
    Use of a breeder reactor assumes nuclear reprocessing of the breeder blanket at least, without which the concept is meaningless. In practice, all proposed breeder reactor programs involve reprocessing of the fuel elements as well. This is important due to nuclear weapons proliferation concerns, as any nation conducting reprocessing using the traditional aqueous-based PUREX family of reprocessing techniques could potentially divert plutonium towards weapons building. In practice, commercial plutonium from reactors with significant burnup would require sophisticated weapon designs, but the possibility must be considered. To address this concern, modified aqueous reprocessing systems, which add extra reagents, forcing minor actinide "impurities" such as curium and neptunium to commingle with the plutonium, have been proposed. Such impurities matter little in a fast spectrum reactor, but make weaponizing the plutonium extraordinarily difficult, such that even very sophisticated weapon designs are likely to fail to fire properly. Such systems as the TRUEX and SANEX are meant to address this.

    Even more comprehensive are systems such as the Integral Fast Reactor (IFR) pyroprocessing system, which uses pools of molten cadmium and electrorefiners to reprocess metallic fuel directly on-site at the reactor.[9] Such systems not only commingle all the minor actinides with both uranium and plutonium, they are compact and self-contained, so that no plutonium-containing material ever needs to be transported away from the site of the breeder reactor. Breeder reactors incorporating such technology would most likely be designed with breeding ratios very close to 1.00, so that after an initial loading of enriched uranium and/or plutonium fuel, the reactor would then be refueled only with small deliveries of natural uranium metal. A quantity of natural uranium metal equivalent to a block about the size of a milk crate delivered once per month would be all the fuel such a 1 gigawatt reactor would need.[10] Such self-contained breeders are currently envisioned as the final self-contained and self-supporting

    WIKI
     
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  7. James R Just this guy, you know? Staff Member

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  8. Nasor Valued Senior Member

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    Why do I get the feeling someone is trying to get us to do homework for them?
     
  9. lambogiggy Lambo Giggy Registered Senior Member

    Messages:
    3
    Well I am actually looking into a alternative energy. You see I live in South Africa unlike America SA is a 3rd world country (which is funny all my TV is on your programs but there is nothing about SA) but any way USA, Euro & China all got more than one source of energy now SA only has one so the whole point of this post is to see if it is a viable options.

    Wind turbines are space users, Hydro- possible, Geothermic way to advanced for us Solar is way to expensive here it costs (SA +- R10,000 for USA +-$1500) so this is why i started the post to find opinions.

    Like Xylene was very helpful with cautions about nuclear reactors but also gave alternatives <bio fuels, tidal, & solar> I would actually like to thank Xylene whilst i got the chance to.

    cosmictraveler was helpful with telling me about another type of reactor that has a better yield also THANK YOU FOR YOUR INPUT.

    to conclude this is getting very long but proving my point YES you are HELPING me with my homework and i appreciate it very much.

    James R thanks for the link

    Lambogiggy

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    Last edited: Jul 13, 2009
  10. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Selected text from: http://en.wikipedia.org/wiki/Thorium_fuel_cycle

    SUMMARY: “A thorium fuel cycle offers several potential advantages over a uranium fuel cycle, including greater resource abundance, (1) superior physical and nuclear properties of fuel,(2) enhanced proliferation resistance, (3) and reduced plutonium and actinide production.(4) ...”

    Some Details:
    (1) Thorium,Th, is at least 3 times more abundant than Uranium and Th requires no enrichment as only one isotope exists in significant amounts (I.e. >99% is stable, but fertile, Th232. In contrast, only 0.7% of natural Uranium is the desirable U235.) There has been very little searching for Th deposits as current needs of Th are fully satisfied as a by-product of refining Rare Earth elements. (I’m not sure, but think the main demand for Th is the construction of mantles for gas lamps.) Probably much more can be found. AFAIK, only India, which has little uranium has actively prospected for Th.

    (2) Neutron capture in Th leads to the production of U233, even in a standard thermal neutron reactor (Fast breeder reactors can be used but are not required). The neutron capture cross section of Th is about three times larger than when producing fission in U235 or U233 so breeding more fuel than burning is easy. Furthermore, when U233 undergoes fission, it produces twice as many neutrons as U235 does on average.

    (3) When a neutron is captured by Th232 it can lead to the production of U233, which like U235 is long lived and thus not very radioactive. U233 is both a much better nuclear fuel (or bomb material) than U235; however, when U233 is produced some U232 is also produced, which is a very dangerous and strong emitter of gamma rays. I.e. Uranium-232 has a relatively short half-life (73.6 years) and because its mass is only 1 unit (not 3 as U238) different from the U233 produced, removal of the U233 to get bomb material is much more difficult than enriching the U235 percentage wrt U238 to get bomb material. Any one, such as N. Korea, who wants to get bomb material will run fast neutron reactor and make Plutonium which can be chemically separated instead of try to do the dangerous and difficult separation of U232 from U233.

    The reason why the world now has Uranium reactors is that the governments initially wanted to make bombs and compact reactors for nuclear submarines, not nuclear power, and that is tough to do with Thorium.

    (4) That is just the way it is – why, if known, requires a deep understanding of nuclear structure.
     
  11. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    2,520
    Billy: How difficult of an impurity is U-232 in the U-233? I.E., does it have to be removed in order to make a bomb? What is the production method of the U-232? U-233 is easy, i.e. bombardment of Th-232 to form Th-233, which then twice beta-decays forming U-233. So where does the U-232 come from?

    There has been some work on U/Th reactors. However, I believed that there needed to be excellent control over the system, as the U-233, as you mentioned, makes a superb fissionable material and should be easy to make into a bomb too. So how does this U-232 impurity arise?
     
  12. tuberculatious Banned Banned

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    987
    I think we should build more matter-exchange generators.
     
  13. spidergoat Valued Senior Member

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    51,740
    No.

    No nuclear plants are coming on-line within the next 5 years. We cannot convert to electric cars because the grid cannot handle it, and these days we cannot get financing. The only realistic solution to our energy crisis is simple, to get used to using less energy. That is our future. Our lifestyle will die with this generation.
     
  14. ElectricFetus Sanity going, going, gone Valued Senior Member

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    18,140
    Incorrect: if we charge electric cars at night using off-peak power we could replace ~80% of are cars/small truck transport with electrics without a single new power plant, in short smart griding will do more then making new power plants.

    http://www.greencarcongress.com/2006/12/doe_study_offpe.html

    I'm all for more nuclear power, even the generation III reactor now under proposal to build are significantly safer then todays reactors, and nuclear waste is a whole lot easier to handle the climate change from spewing out carbon dioxide and other pollutants. Molten salt thorium reactors or even pebble bed reactors promise impressive decrease pricing and even greater safety then GenIII (GenIV reactors).
     
  15. spidergoat Valued Senior Member

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    51,740
    The so-called smart grid does not presently exist. The exercise in sustaining the unsustainable is doomed to fail. Why continue investing in a future around automobiles? ...a technology that has no future and contributes to the degradation of our landscape? The road maintenance alone cannot continue.
     
  16. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    My post 7 Wiki link states:

    "... Uranium-232 is also formed in this process, via (n,2n) reactions with 233U, 233Pa, and 232Th:

    (Here Wiki gives the equations, but they do not copy)

    Uranium-232 has a relatively short half-life (73.6 years), and some decay products emit high energy gamma radiation, such as 224Rn, 212Bi and particularly 208Tl. ... Because 232U cannot be easily separated from 233U in used nuclear fuel, these hard gamma emitters create a radiological hazard which necessitates remote handling during reprocessing." {and in all stages of bomb fabrication plus shielding for storage. Possibly damage to bomb electronics?}

    Further, the 231Pa (with a half life of 3.27 × 104 years) formed via (n,2n) reactions with 232Th (yielding 231Th that decays to 231Pa) is a major contributor to the long term radiotoxicity of used nuclear fuel. ..."

    I doubt that some U232 would stop the bomb from functioning well and N. Korea might not mind irradiating the workers and solders handling the bomb, but why lose these skilled people when Plutonium bombs are safe to handle and the Plutonium can be chemically separated from the Uranium that produced it?

    That control is very much easier to create as the U232 "contaminate" in the U233 is powerful source of gamma rays - hard to hide. Even the remote handling and shielding of the fabrication facility would make it easy for inspectors to find / hard to hide.

    I am not sure but think that U235 has such a long half life that a bomb's requirement could safely be carried in a simple back pack for a few days with relative little risk to the carrier. I have read that one could place their hand directly on even spent fuel rods, which have small amounts of lots more radioactive material than U235, and not get a medically significant does. You do not want to be close to even a gram of U232, as I understand it.

    I am not very knowledgeable in all this. I just know "Wiki level" and then only by reading it there.

    I think mankind has twice foolishly chosen his energy source:

    (1) Uranium as the nuclear fuel - It make plutonium chemically separable for bombs and only 0.7% of it is useful for energy. 100% of Thorium is useful and there is probably more than an order of magnitude more of it available. Plus hard to make into bombs and in a power reactor both more efficient in neutron used (small reactors are possible) and also produces much less radioactive waste per KW hour generated.

    (2) High tech and expensive attempts to use solar energy which require separate storage systems for more cost, if any significant fraction of the electric load were to be generated by them. (If more than ~10%, you cannot just use the grid as a "free" storage system.) It costs nothing to grow green plants in the tropics and they inherently provide the energy storage. You could just burn them, but some can easily make liquid fuels of cars and diesel trucks.

    Stupid choice (1) happened as government wanted bombs and compact reactors for submarines.
    Stupid choice (2) happened so Oil Companies can control the energy supply.
     
  17. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    23,198
    That is a very narrow US POV. In China they are coming on line about a new one ever month.

    By 2050 China plans to have 30Fast breeder reactors and be self sufficient in nuclear fuel. Also the prototypic of the first fluidized bed reactor is under construction now, but it is mainly a design "borrowed" from the now discontinued German program. (The Germans "greens" got law making all nuclear reactors illegal soon so Germany will be importing ever more electric power from France where they are not so ignorant.)

    Many think fluidized bed reactor are cheaper, more efficient power producer and even safer. I do not know. I think the idea is that the breeders will make the fuel for the fluidized bed reactors.
     
  18. spidergoat Valued Senior Member

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    51,740
    That's because China doesn't give a damn about the environment, or the safety of the people destined to live near these things. I don't think any breeder reactor has ever been self-sustaining, in spite of the promise of such.
     
  19. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Where do you think N. Korea gets its bomb Plutonium from? Again I am not well versed in this and think breeders are not required, as the Chernobal reactor was designed to make plutonium, as I undersand it.

    But I find it very hard to believe you are correct that no "breeder reactor has ever been self-sustaining" Do you have a link supporting that claim?

    China is very concerned about the environment - they closed 3000 small coal mines and are rapidly building nuclear units , hydro units and starting the make super critical steam coal fired units, which will reduce their CO2 from coal based power by more than 1/3 per KW hour generated.
     
    Last edited by a moderator: Jul 13, 2009
  20. spidergoat Valued Senior Member

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    51,740
    I read it in "Radioactice Boy Scout", about a kid who managed to assemble a working model breeder reactor in his backyard for a merit badge.
     
  21. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I thought your source was something like that. Here is a little more accurate quote from Wiki:

    "FBRs have been built and operated in the USA, the UK, France, the former USSR, India and Japan.[4] An experimental FBR in Germany was built but never operated." (As noted in my prior post the German Greens have killed a new reactors in Germany and will tear down those now working soon (I forget when.)

    Quote from: http://en.wikipedia.org/wiki/Fast_breeder_reactor

    The US's AEC basically stopped US work on FBR. I think mainly to assure the continued existance of high uranium prices and the exisitng US technology (not much of it left now after 30 years)

    Following link discusses this - almost a conspiracy link with "gag orders" to Argonne labs staff that worked on the FBR etc. the link claims.
    See: http://tinyurl.com/cwvn8n Read the paragraph that begins just at the end of page 137. AFAIK, this book's Chapter 5 is a good dicussion, although biased, of the FBR.
     
    Last edited by a moderator: Jul 13, 2009
  22. ElectricFetus Sanity going, going, gone Valued Senior Member

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    18,140
    smart-griding is not hard to build, for example all it would require is a cellphone receiver in the car that can communicate with the power company to know when the start charging and at what rate.

    I would agree trains and mass transit would be more efficient but the cost in installing it would likely not be competitive against smart griding (a feature needed no matter what) and electric cars. The roads are already there, high speed train tracks are not.
     
  23. spidergoat Valued Senior Member

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    51,740
    We already have train tracks, right-of-ways, it's old technology, and it's our future.

    Everything that depends on technology moves exponentially faster, it seems. Everything, that is, except commuter rail in Massachusetts.

    A pair of yellowed train schedules from the first part of the 20th century provides the proof. They show at least five instances when steam-powered trains from yesteryear outpaced today's diesel trains into Boston during morning rush hour.

    The quickest express train from Scituate to Boston in 1911 outpaced current morning rush-hour trains by 11 minutes. The fastest morning ride from Framingham came in 10 minutes quicker in 1925 than it does today.​
     

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