>... presented with data

Let's see... You take a report 16 years old and then you cherry pick the 270 number by ignoring all the other factors that wold be relevant if the world decided to get all of its energy from nuclear energy.

According to your link, you ignored reprocessing and using breeder reactors Relying on breeder reactors adds over another 8,000 years to the expected lifetime.

That 8,000 year number is conservative for several reasons:

Over time, we get more efficient use of nuclear fuel:

>...Over the years 1980 to 2008 the electricity generated by nuclear power increased 3.6-fold while uranium used increased by a factor of only 2.5.

We've continued to more sources of uranium in recent years:

>...The world's known uranium resources increased by at least one-quarter in the last decade due to increased mineral exploration

http://www.world-nuclear.org/information-library/nuclear-fue...

The report simply makes a mention of thorium as an unconventional resource, but doesn't include it in the calculation.

>...Today uranium is the only fuel supplied for nuclear reactors. However, thorium can also be utilised as a fuel for CANDU reactors or in reactors specially designed for this purpose. Neutron efficient reactors, such as CANDU, are capable of operating on a thorium fuel cycle, once they are started using a fissile material such as U-235 or Pu-239.

>...Thorium is reported to be about three times as abundant in the Earth's crust as uranium.

http://www.world-nuclear.org/information-library/nuclear-fue...

With breeder reactors, it becomes economical to get uranium from sea water:

>...Such arguments ignore the fact that usual estimates of the
world’s uranium resources refer to quantities available at the current
market price of about $40 per pound. At that price, uranium supply
contributes about 0.2 cents/kW h to the cost of electricity from
light-water reactors. However, if used in breeder reactors, the
cost/kW h is reduced by more than a factor of 100, so one can
afford to use much more expensive uranium. For example, uranium
costing $1000/lb would contribute only 0.03 cents/kW-h to the cost
of electricity and would thus represent less than 1 % of the total
cost. At that price, the fuel cost would be equivalent to that of
gasoline priced at a half cent per gallon.
How much uranium is available at a price of $1000 per pound?
There are large supplies available at far below that cost in the
Conway granite of New England and the Chattanooga Shales of
Tennessee, but for the longer-range viewpoint we concentrate here
on uranium from the oceans. It now seems quite certain that
uranium can be extracted from the ocean at well below $1000 per
pound (best estimates are that current technology can produce it at
$200–400 per pound) and there is even some optimism that it can
1
become competitive at current market prices ($40/lb). It is clear,
then, that uranium from seawater must be considered as a
completely acceptable fuel for breeder reactors, contributing less
than 1% to the cost of electricity. In terms of fuel cost per million
BTU, even at $400/lb the uranium cost is only 1.1 cents, whereas
coal costs $1.25, OPEC oil costs $5.70, and natural gas costs $3–4.
...
All of the world’s present electrical usage, 650 GWe, could therefore be supplied by the uranium
in seawater for (4.6×10 /650) = 7 million years.

http://large.stanford.edu/publications/coal/references/docs/...

Just in the last couple of years there have been advances in getting uranium from seawater which would lower the cost:

>...New technological breakthroughs from DOE’s Pacific Northwest (PNNL) and Oak Ridge (ORNL) national laboratories have made removing uranium from seawater within economic reach and the only question is - when will the source of uranium for our nuclear power plants change from mined ore to seawater extraction?
...
Stephen Kung, in DOE's Office of Nuclear Energy, says that “Finding alternatives to uranium ore mining is a necessary step in planning for the future of nuclear energy.” And these advances by PNNL and ORNL have reduced the cost by a factor of four in just five years. But it’s still over $200/lb of U3O8, twice as much as it needs to be to replace mining uranium ore.

Obviously no one is going to pay double (or more) just to get uranium from seawater, but if the price of uranium start to get expensive due to shortages, we can get uranium from seawater with relatively little impact on the price of electricity.

>...the reaction is a fuckton "but what if"

You need to re-read what I wrote. I did not write a bunch of "What if" hypotheticals. I pointed out you missed a huge number of factors that would influence the result. It would be as if someone claimed we couldn't supply the world's power through solar/wind because of the increased need for rare earths and they didn't include the impact of recycling or opening up mining operations in other parts of the word that are currently uneconomical. I would call them out on that just like I did here.