[Tuna-Fish]

> rough estimate shows that if all our current electric energy demand would be satisfied with Uranium, the reserves would run out in roughly 10 years.

While strictly correct, this is extremely misleading. Current resources would be exhausted in a decade, but resources are defined as the known deposits extractable under current market prices. Should we actually start using a lot of uranium, the price would spike, which would lead to a lot more deposits becoming economically available. This has almost no effect on the cost of nuclear power, as the cost of the raw uranium isn't a large part of the cost of producing power.

The end game there is when the price rises sufficiently for extraction from seawater becoming profitable. The world's seas have ~1000 times more uranium than conventional ground-based resources.

Nuclear fuels will not run out in this millennium.

[orbifold]

The total known ground resources are estimated to be roughly seven times larger than the current mining reserves. So this gives you at most a factor of ten. Of course there are other unrealistic assumptions in those estimates. Realistically you would use other sources of electric energy for instance. I don't now if the Thorium reserves are roughly four times larger than the current Uranium reserves or four times larger than the amount of Uranium that could feasibly be extracted from the ground. In any case, both are only a solution for the near future, that is the next 50-100 years or so. With current technology it would not make sense to extract Uranium from the Ocean, its concentration is $10^{-9}$, it can be commercially extracted from rocks with $10^{-4}$ concentration. It does not possible to filter huge amounts of seawater for such insignificant quantities of Uranium.

[venomsnake]

How about energy return on energy investment. You have to vaporize a lot of water (of course you will have all those gold, iron, rare metals "waste" which will help the economic case).

[maxerickson]

Research has focused on other methods:

http://en.wikipedia.org/wiki/Uranium_mining#Recovery_from_se...