When the bottle is empty, there is no more; you have to get another bottle of wine or make do with water.
True enough for drinks out of a bottle; but only simpletons think it works the same way with natural resources. Fuels, for example, have no bottom of the barrel; they just have a price, and when the price (in money or other constraints) becomes too high, another fuel is substituted.
Uranium is now priced at $40/lb, and at that price the supply would last only some 50 (or 100? or 40?) years. Breeder reactors can extend the supply by a factor of about 100 (because they use U 238, forming some 99% of uranium ore, and now going to waste), extending the supply to some 1,000 years
¾at that same price of $40/lb.But when you have breeders, says Prof. Bernard Cohen (U. of Pittsburgh) in one of his marvelous papers (not yet published), you can afford to go to higher prices; you can, for example, extract uranium from sea water (and the Japanese are seriously looking into that method, AtE Dec 79) at a price of not more than $1,000/lb, and almost certainly well below that. At that price, the fuel cost (which is always very much smaller than the investment cost for all types of nuclear plants) would still only contribute less than 1%, or 0.03 cents, to the cost of a kilowatt-hour of electricity.
Thus, sea water will be an economically acceptable source of fuel for breeders (not to mention cheaper sources of uranium and the thorium/uranium 233 cycle). At present rates of power consumption, there is enough uranium in the sea to last for 7 million years
¾or so one might think by using elementary arithmetic.Well, don't use elementary arithmetic; remember that uranium, like salt, is being washed into the sea by the world's rivers. (Before better methods were available, the salt concentration of the sea was used to estimate the age of the earth.) So the sea is not only getting saltier, it is also getting urani..., ura..., ur... ahum, well, yes. Its uranium concentration is increasing.
Which means that nuclear fission via uranium 238 (not to mention the thorium cycle) can give energy for more than the 7 million years found by simple arithmetic; in fact, Cohen's calculations show that one can maintain a steady ("renewable") state forever by withdrawing no more than 16,000 tonnes of uranium from the sea every year
¾which corresponds to 25 times the present world electricity consumption, and twice the present world consumption of all energy.Good! For a moment there we were worried about powering our press for the December issue in the year seven million nineteen-eighty.
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Vol. 8, No. 4
Newsletter: Access to Energy Newsletter Archive Volume: Volume 8 Issue/No.: Vol. 8, No. 4 Date: December 01, 1980 04:47 PM Title: A turning point
Copyright © 2004 - Access to Energy Newsletter Archive
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