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Uranium power/weight ratio in fission reactors

  1. Aug 26, 2005 #1

    I have a couple of more questions for all the kind and learned people here.

    Are there any (approx) benchmarks for quantifying how much uranium ore (kg) is going to be rquired in order to generate a given amount of electricity over a specific length of time? Let me clarify....

    Hypothetically speaking, if I wanted to generate 1000 million watts of power per day (10^9), continuously, over a period of 10,000 years, how much uranium ore (mass, in kg) would I need to dig out of the ground in order to satisfy this demand?

    What would be a technical definition or name for this kind of power/weight assessment?

    Thanks for any suggestions.

    (PS & off topic: In case anyone is wondering why, I want to power the lighting inside my interstellar ark, the 'Centauri Princess', featured in my novel : First Ark to Alpha Centauri!) :smile:
  2. jcsd
  3. Aug 26, 2005 #2


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    Staff: Mentor


    The term of Watts/kgU is specific power. One can also calculate power density in the fuel Watts/m3.

    However, the conventional term is burnup, GWd/tU or GWd/kgU or MWd/kgU, which describes the energy produced per unit mass of U. Some use the mass of UO2, as in MWd/kgUO2.
    To get the mass of U, one need only determine the energy and time over which the energy is generated.

    Currently in many commercial power reactors (LWRs), typical maximum rod average burnup is about 55-60 GWd/tU (Although fuel can conceivably reach about 70-75 GWd/tU without problems), where 1 tU = 1000 kgU. In fast reactors, burnups of 100-200 GWd/tU are possible.

    The principal technical issues with respect to LWR fuel include corrosion of the cladding and rod internal pressure. The objective here is to make sure that fission products are retained in the fuel rod throughout operation and subsequent handling.
  4. Aug 26, 2005 #3
    Thanks. I suppose everything will depend upon how much power consumption will take place. Since the interior surface area of my ark will be of approx. 600 square kilometres, and the population will be around 3,000 people (on average) along the 50,000 year long journey (!), I wonder if there are any Earthly parallels to compare this with?

    I wonder if there are any figures available for the total yearly electricity consumption of a small-town community of 3,000 people somewhere in N. America...(how much power wattage they consume over 1 year)...
  5. Aug 26, 2005 #4


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    Well "somewhere" can be a broad range of electrical usage. Hill towns in Mexico might compare decently enough to a little town in the US or Canada but the larger the population in a city, the larger the discrepencies get!

    If you'll go to the CIA world factbook, you can determine the following figures.

    Per capita electrical generation in the US: ~12200kwh/year
    Per capita electrical generation in Canada: ~14800kwh/year
    Per capita electrical generation in Mexico: ~1780kwh/year

    Also, I believe it takes a ton of uranium ore to make 1 pound of the type of uranium used in nuclear power plants. Wonder where Morbios is, bet he could figure this stuff out off the top of his head.
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