Reply #10: Peak uranium? [View All]

[NNadir]

And your basis for this contention is what exactly?

And peak Thorium?

Why don't you offer us a calculation showing the world uranium reserves, the world thorium reserves, and the fuel cycles for which you are making these claims.

Or is this the usual pull it out of a hat and say it's true because you heard it somewhere on the internet.

World energy demand is now about 500 exajoules. Please show us the basis of your claim.

While you're at it, maybe you can give us the technical details on why this report from the MIT nuclear engineering groups is full of shit. It's somewhat dated, and, though not up on the latest, it reads:

" Mining Uranium from Seawater Seawater uranium at an affordable price is the ultimate guarantee of uranium availability for any nation with access to the ocean. Because of the very large
amounts of uranium in the oceans—about four billion tonnes, or about 800 times more than the terrestrial resources recoverable at a price of $130/kg or less— the possibility of recovering uranium from seawater has received considerable attention over the past four decades. The major drawback is the fact that the uranium concentration is very low, about 3 ppb. This implies that the extraction cost will be high unless the uranium recovery efficiency from seawater is high and adequate seawater flows can be established without active pumping. Ongoing R&D efforts in Japan over the last decade on uranium adsorbents and seawater processing schemes have met this challenge; both the technical feasibility and economic viability of the process have been established. For example, the most recent (1993) cost estimate was about 40,000 yen per kg of recovered uranium, equivalent to about $100/lb U3O8 (U.S.$1D125 yen).28 Although this is about 10X the current market price of uranium, it would increase the busbar cost of LWR electricity by only 10%, and that of more efficient reactors by even less. The resulting electricity cost would be highly competitive with the cost of electricity from a breeder reactor even under the most optimistic estimates of the capital cost differential between the breeder and the conventional LWR..."

http://www.princeton.edu/~globsec/publications/pdf/10_2%20127%20150%20Lidsky.pdf

Speaking of current technology, please tell us to, what percentage of uranium is consumed in each pass through a reactor.

Maybe you'd like to give us a considered opinion of how much energy 4 billion tons of uranium represents. Also tell us what it means that the sea is saturated with respect to uranium.

I will note that I disagree with the authors of this report in many areas, most seriously about the advisability of the once through cycle, but I concur very much with the notion that the 1950's prediction of the depletion of world uranium reserves by 1990 - which lead to our less than optimal, but still successful, choice of our current technology - was somewhat exaggerated.

Uranium is not a particularly rare element at all. This graph, with the atomic number of the elements on the abscissa and the log crustal abundance on the ordinate.



Looking at this graph we see that both thorium and uranium have crustal abundances comparable to elements like tin, like bromine, is in much greater abundance than tungsten, bismuth, silver, is roughly as abundant as molybdenum, about 5 times as available as cadmium.

Finally, the world has accumulated 1000 metric tons of plutonium, representing 80 exajoules of energy, or 11 years worth of fueling for the 361 GW of electricity now being produced by nuclear means. Generally this plutonium is considered too expensive to recover because uranium is so cheap, the equivalent of gasoline at 0.007 cents per gallon whereas the plutonium would be 20X more expensive, the equivalent of gasoline at 0.01 cents a gallon. People have to be dragged kicking and screaming into spending extra money to burn this plutonium, because nobody needs it, as fissionable resources are so plentiful and so inexpensive. (This contrasts considerably with the predictions of people in the 1950's who thought we must have fast breeder reactors because uranium was so rare. They had no idea that the element was about as common as tin.)

Finally we have thorium, an element that is so cheap that people generally throw it away rather than recover it from the Monzanite ores from which it is produced. (Monzanite is worked to recover the lanthanides to make television sets and other items.) Given that all we have to do to recover this thorium is to walk over to the monzanite tailings pile, how do you claim that nuclear resources are about to be depleted?

Fully cycled, from the sea alone, uranium resources can last many hundreds of thousands of year, even if the sea were not replenished by exposure and weather of crustal rock - which would tend to replenish depleted waters. Thorium can extend those resources for hundreds of thousands of years further.

Depending on the rate or recharge of uranium from crustal rock to the sea, it is possible to consider uranium resources as nearly inexhaustible.