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Recovering sea-water uranium - what advantage Fusion?

  1. Nov 23, 2006 #1

    Andrew Mason

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    Apparently efforts to recover U from seawater were abandoned in the 1970s when studies concluded that it would cost about $1400 / lb. At the time, the spot price of U was about $40/lb.

    If the cost of recovering U from sea water can be brought down to $100 a pound, (current price is around $62 US/lb), there would appear to be a virtually unlimited supply of U for nuclear reactors. Work on U recovery from seawater in Japan indicates that the cost may be approaching this level. Given the huge enrichment cost, the actual cost of U is a pretty small part of the total fuel cost.

    Question:

    So what would the advantage be of fusion? In strictly economic terms, the enormous research and development cost for a fusion reactor would seem to be better directed at recovering U from seawater and using the U in seawater instead of the H for energy.

    AM
     
    Last edited: Nov 24, 2006
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  3. Nov 23, 2006 #2

    berkeman

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    Yeah, not many people seem to realize that fusion has nuclear waste as well (less, but still non-zero). The main advantae of fusion versus fission seems to be that a reactor meltdown stops on its own with fusion. But the disadvantage so far with fusion seems to be that the easier RX to achieve are plenty dirty. But if we could sustain the cleaner fusion RX....
     
  4. Nov 24, 2006 #3

    Andrew Mason

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    I have a feeling that if the amount of research effort that has been put into fusion had been applied to making fission technology safe (as well as addressing the troubling security issues) we could have solved these problems by now. The main problem with fission is keeping enriched uranium or fissionable plutonium, as well as the highly radioactive fission waste, away from terrorists and rogue nations.

    If U can be mined from seawater, we have a potentially serious international problem. I think we would do well to address this issue now before the technology starts proliferating uncontrollably.

    AM
     
    Last edited: Nov 24, 2006
  5. Nov 24, 2006 #4

    Morbius

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    Andrew,

    Deuterium is even MORE plentiful in seawater than is Uranium.

    Deuterium has an abundance of about 0.015% relative to all Hydrogen.
    Water is 2/18 or about 11% Hydrogen.

    Therefore water is about 0.0000167 Deuterium = 1.67e-5 Deuterium or
    16,700 parts per billion. Uranium is about 3 parts per billion in seawater,
    and the fissile U-235 is 0.7% of that.

    Additionally, you get more energy per unit mass in fusion than in fission.
    Fission gives you about 1 MeV / amu. Fusion gives you about 3.5 MeV/amu.

    So the fusion energy content of the Deuterium in seawater represents
    almost 3 MILLION TIMES as much energy as the fission energy content
    of the U-235!

    THAT's why it's worth going after the fusion technology.

    Dr. Gregory Greenman
    Physicist
     
    Last edited: Nov 24, 2006
  6. Nov 24, 2006 #5

    Morbius

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    Andrew,

    Those problems are essentially solved with "inherently safe" or
    "passively safe" reactors such as Argonne's Integral Fast Reactor or IFR:

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

    The IFR can benignly handle accident conditions; and is proliferation resistant as
    Dr. Till explained. Too bad President Clinton cancelled it.

    If a rogue nation is bent on developing nuclear weapons, they can do
    that without nuclear power or help from Western technology.

    At the start of the Gulf War in 1991, Iraq was only about a few months
    away from having nuclear weapons; all done with indigenously developed
    technology and resources. See the article by Dr. David Kay, USA's chief
    nuclear weapons inspector, and Dr. Jay Davis, then Associate Director
    of Lawrence Livermore National Laboratory beginning on page 20 of the
    July 1992 issue of "Physics Today".

    Uranium is one of the most uniformly distributed elements in the Earth's
    crust. ANY nation has sufficient Uranium in the ground within its borders
    to make nuclear weapons. They just have to dig it up - they don't need
    seawater.

    The main hurdle that the world has relied on is the difficulty of obtaining
    enrichment technology. That hurdle is there for seawater uranium too.

    However, a determined nation, like Iraq and Iran; can overcome that
    hurdle.

    Dr. Gregory Greenman
    Physicist
     
  7. Nov 24, 2006 #6

    Andrew Mason

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    Gregory,

    There are an estimated 5 billion tonnes of U in sea-water. So does it really matter if fusion gives more energy?

    We have only used 170,000 Tonnes of U in all reactors in the world to date. So even a million tonnes represents about a hundred years of supply. A billion tonnes represents tens of thousands of years supply. There is also more Thorium than U in sea water. So there is another couple of hundred thousand years worth of supply. And that does not even touch the U in granite, coal etc.

    Did he give a reason for cancelling it?

    All good points. But doesn't that mean we just have to start now by setting up a world system for controlling mining and particularly the enrichment of U? If we say it can't be done I think we are conceding that humanity will end up with a nuclear catastrophe. All we have to do first is establish world peace.... then it should be easy to control U.:rolleyes:

    AM
     
  8. Nov 25, 2006 #7

    Morbius

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    Yes - but extracting that 5 billion tonnes requires running the ENTIRE volume
    of the ocean through your extraction facility to recover all that.

    Another way of looking at it, is for a given amount of energy; you only
    have to process 1/3,000,000 of the amount of water for fusion as you do
    for fission from seawater uranium.

    Yes - it was a campaign promise he made to the anti-nukes that
    supported his election.

    That's what the NPT - the Nuclear Non-Proliferation Treaty is all about.
    You get nations to agree not to pursue a path to nuclear weapons.

    The problem is ENFORCEMENT!! We have cases like Iraq, Iran, and
    North Korea that were found to be CHEATING on their treaty obligations.
    What did the United Nations which oversees the treaty do?

    In a word; NOTHING!!!! There were no downsides for previous violators;
    so why should any nation abide by the treaty?

    Dr. Gregory Greenman
    Physicist
     
    Last edited: Nov 25, 2006
  9. Nov 26, 2006 #8

    Andrew Mason

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    Thanks very much for the link on the IFR. After further reading on this reactor it is apparent that the politicians may not have fully understood the potential of this technology.

    The most remarkable feature of the IFR seems to be its ability to run on its original fuel for decades by reprocessing and reusing it. This also has the advantage of eliminating long term waste storage. Its design also made it very difficult and very unlikely for anyone to make a nuclear weapon out of the fuel.

    It occurred to me that Clinton may have killed it at the behest of the Uranium mining industry. The IFR would have put them all out of business.

    AM
     
  10. Nov 27, 2006 #9

    Morbius

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    Andrew,

    The potential of the IFR was made VERY CLEAR to government officials by my
    former collegues at Argonne like Dr. Till. After years of research and testing,
    they had a reactor design that "inherently safe", proliferation resistant, and
    could burn-up long lived nuclear waste. One would think that would be an
    easy sell. However, they ran into a "buzz-saw"; one of the most anti-nuclear
    Administrations to come to power in Washington. The Clinton Administration
    with Al Gore running energy and environmental policy; just didn't want to hear
    about it.

    For example, a very respected government scientist, Dr. William J. Happer;
    suggested that measurements be made of the ozone hole problem to see if
    it was as big a problem as had been claimed. That didn't sit well with Al Gore;
    and Dr. Happer was promptly fired.

    DOE Secretary Hazel O'Leary announced that LLNL would be shutdown; a
    decision she later reversed when LLNL scientists went along with the
    Administration's policy vis-a-vis the CTBT. If the scientists didn't
    "toe the line" in the Clinton Administration; they were silenced.

    It wasn't the uranium mining industry.

    Bill Clinton and Al Gore CAMPAIGNED on the fact that federal monies were given to
    national labs to work on nuclear programs. They promised to put an end to that
    practice and shutdown research on nuclear power. That's what they did - and said
    so at the time.

    Clinton stated that nuclear power research "wasn't needed" in his first
    State of the Union address in 1993:

    http://www.presidency.ucsb.edu/ws/index.php?pid=47232

    "We are eliminating programs that are no longer needed, such as
    nuclear power research and development. We're slashing subsidies
    and canceling wasteful projects."


    --President William J. Clinton, February 17, 1993

    Dr. Gregory Greenman
    Physicist
     
    Last edited: Nov 27, 2006
  11. Nov 27, 2006 #10

    Andrew Mason

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    Gregory,

    My comment was intended to be facetious - just pointing out that it would put uranium mining out of business. It was ultimately Congress that voted to end funding.

    It appears that a NAS report in 1994 opposed development of plutonium fueled reactors, including the IFR, on security grounds. So Clinton was not without some support. I haven't been able to find that report. But it seems to me that the fuel cycle from thermal reactors with its high level (including plutonium) waste is as much of a security threat.

    AM
     
  12. Nov 27, 2006 #11

    Morbius

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    Andrew,

    The IFR addresses those concerns. In the IFR; plutonium NEVER LEAVES the
    high radiation area around the reactor. The IFR features on site reprocessing of
    spent fuel. That's why the IFR uses metal, rather than ceramic fuel.

    When spent fuel is removed from the IFR, it is reprocessed by "halide slagging" and
    electrorefining. Any plutonium that remains in the spent fuel is sent back to the
    reactor as Dr. Till stated in his interview. Only short-lived fission products leave the
    IFR as waste.

    I find it difficult to believe that the NAS included the IFR in a report citing the
    security problem. I'm sure the NAS did, or SHOULD have; understood that
    there is no security problem with plutonium in IFR waste. The plutonium produced
    by the IFR is immediately recycled back to the IFR as fuel.

    Additionally, as Dr. Till stated; the IFR reprocessing scheme doesn't separate out
    the plutonium by itself. It leaves other actinides and other plutonium isotopes mixed
    in with the Pu-239. As Dr. Till stated; it is impossible to use IFR waste plutonium
    as nuclear weapons fuel.

    As Dr. George Stanford pointed out, the authors of the NAS study evidently didn't
    understand the proliferation resistance of the IFR:

    http://www.nationalcenter.org/NPA378.html

    which also details the conclusions by nuclear weapons designers at
    Lawrence Livermore National Laboratory:

    "Some people do say that, but they're wrong, according to expert bomb designers
    at Livermore National Laboratory. They looked at the problem in detail, and concluded
    that plutonium-bearing material taken from anywhere in the IFR cycle was so ornery,
    because of inherent heat, radioactivity and spontaneous neutrons, that making a bomb
    with it without chemical separation of the plutonium would be essentially impossible -
    far, far harder than using today's reactor-grade plutonium."


    Real nuclear weapons experts from Lawrence Livermore shot down the contentions
    of the authors of the NAS report [ who aren't nuclear weapons experts ]. IFR fuel
    cycle plutonium can't be used as bomb fuel.

    So what is the security concern?

    Dr. Gregory Greenman
    Physicist
     
    Last edited: Nov 27, 2006
  13. Nov 27, 2006 #12

    Andrew Mason

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    I agree that the IFR does not appear to produce material that could be easily used to produce a nuclear bomb. Not so with conventional reactors.

    AM
     
  14. Nov 27, 2006 #13

    Morbius

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    Andrew,

    Even then.

    The DOE has acknowledged that one can use so-called "reactor grade" plutonium,
    that is plutonium from the nuclear waste of a commercial power reactor; in the
    making of a nuclear weapon. However, it is difficult to do so; and may be beyond
    the capability of a nascent nuclear proliferant.

    What a nuclear weapons designer wants is plutonium that is made in special
    "production reactors" in which the irradiated fuel is discharged after a relatively
    low burn-up. That's how one gets nuclear bomb fuel.

    A commercial power reactor is a relatively inefficient and expensive way to get
    nuclear weapons material.

    Dr. Gregory Greenman
    Physicist
     
  15. Nov 27, 2006 #14

    Andrew Mason

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    The frightening result, however, is that with a bit of depleted U and a breeder reactor, a rogue nation could easily make a bomb. The controls on depleted U are not nearly as strict as U235 or Plutonium. Depleted U is ubiquitous.

    AM
     
  16. Nov 27, 2006 #15

    Morbius

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    Andrew,

    WRONG!!!!

    You can't get depleted Uranium; i.e U-238 to go critical in even a breeder reactor!!!

    You need fissile material; U-235 and/or Pu-239 to fuel a reactor to turn U-238 into
    bomb material.

    If all you have is U-238 [ depleted Uranium ]; and no fissile material [ U-235 / Pu-239 ]
    then you can't make a bomb or weapons material.

    That's why the controls are on U-235 and Pu-239 and not depleted Uranium [ U-238 ].

    Dr. Gregory Greenman
    Physicist
     
  17. Nov 27, 2006 #16

    Andrew Mason

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    I was not suggesting the U-238 is fissile. But with a neutron source (eg. P-239) (and a reactor) you can turn fertile U-238 into fissile P-239. You could then use the resulting P-239 to turn more U-238 into more P-239 etc. With just a little P-239 and a lot of U-238 you could produce a lot of fissile material. We don't seem to be controlling the depleted U.

    AM
     
  18. Nov 27, 2006 #17
    I think that would take a long while. Even with enriched Uranium, if I remember correctly, it took several months to make enough Plutonium for the first Pu-239 based atomic bomb.

    Also, is a CANDU reactor not considered critical? Or it's fuel not considered depleted Uranium (i.e. natural Uranium is not depleted)?
     
  19. Nov 28, 2006 #18

    Astronuc

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    CANDUs are critical at constant power, and the power level can vary. CANDUs use 'natural' U (~0.7% U-235), although lately the U is slightly enriched in order to reduce the number of discharged fuel assemblies.

    U-238 is fertile. A neutron source (e.g. Po-Be, Pu-Be) has a very low neutron density, so with just a neutron source, it would take a long time to convert kgs of U-238 to Pu-239.

    A friend and colleague of mine used to make logs of U-238 (DU) for Pu-239 production. It was a matter of simply inserting U-238 into a production reactor for many months, then removing the material and sending it to a reprocessing/recovery facility.

    Reactor grade Pu contains amounts of Pu-241 and Pu-242, in addition to fission products (FP), so it would require remote handling to separate the Pu-239 and Pu-240 from the radioactive FP and one would still have Pu-241,242 to deal with.
     
  20. Nov 28, 2006 #19

    Morbius

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    Andrew,

    WRONG again - I'm sorry!!!

    First Pu-239 is not what we call a "neutron source" - it is a fissile isotope; but has a
    very low rate of spontaneous fissions - about 10 fissions/sec per kilogram.

    You are in ERROR in saying that "with just a little Pu-239 and a lot of U-238..."; that
    you could bootstrap your way into having a lot of fissile material. Unless you have
    a "critical mass" of Pu-239 [ NOT "just a litttle" ] - you can't do ANYTHING!!!

    That's why there are the controls on the amount of Pu-239. You aren't allowed to
    have a "critical mass" of Pu-239.

    The reason we don't control the depleted uranium U-238 is because we DON'T NEED to!!

    Besides - if someone wants Uranium; they could dig up natural uranium; at least
    that has some more U-235 in it!!

    Depleted Uranium is even MORE USELESS than natural uranium from the ground
    when it comes to making nuclear weapons.

    Attempting to control depleted uranium would be counterproductive. It would sap
    resources in trying to control the vast amount of a material that has industrial
    uses from commercial airliner ballast to pigments and glazes. All for a
    ZERO payback in terms of increased safety and security.

    Dr. Gregory Greenman
    Physicist
     
    Last edited: Nov 28, 2006
  21. Nov 28, 2006 #20

    Morbius

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    Candyman,

    You are correct. The production reactors at Hanford started operation in September of
    1944. As of July 1945, they had produced enough plutonium for 3 bombs - the bomb
    tested in the "Trinity" test on August 15, 1945 at Alamagordo; the "Fat Man" bomb
    that destroyed Nagasaki; and finally another "Fat Man" that was slated to be used if
    Japan didn't surrender after Nagasaki. This bomb was ultimately detonated in the
    "Crossroads Able" test at Bikini Atoll on July 1, 1946.

    The Hanford production reactors were HUGE!!!! The production of 3 critical masses
    of plutonium in 9 months required a MASSIVE production complex. This is not a
    "backyard operation" by any means. More moderate sized facilities requires YEARS
    to make a critical mass.

    There were 3 production reactors built at Hanford during the Manhattan Project;
    B-Reactor, D-Reactor and F-Reactor. Here's a history of the B-Reactor:

    http://www.hanford.gov/doe/history/files/HistoryofBArea.pdf

    CANDU reactors are critical. The fuel in a CANDU is natural uranium which is
    0.7% U-235. The other 99.3% of the Uranium is U-238.

    The CANDU is moderated by heavy water. Heavy water is one of only two materials,
    the other being graphite; that can moderate a reactor fueled by natural uranium.

    The Hanford production reactors were moderated by graphite. The Savannah River
    production reactors were moderated by heavy water.

    All commercial power reactors in the USA are light water [ ordinary water ] moderated
    and cooled. You can't get an LWR [ light water reactor ] to go critical on unenriched
    or natural uranium. The fuel for an LWR must be enriched to about 3-4% U-235.

    When you remove U-235 from natural uranium; what you have left is depleted uranium.

    Think of natural uranium as milk. The U-235 is the cream or butterfat. Depleted
    uranium is the buttermilk that's left after you make butter.

    Dr. Gregory Greenman
    Physicist
     
    Last edited: Nov 28, 2006
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