As a sanity check, I went and looked up Cohen’s paper; it’s 32,000 tons U per year that rivers bring into the ocean, not per day. Also, the U content of seawater is given as 3 ppb, which is 3 milligrams per 1000 kilograms (or 1 billion milligrams). Here’s the reference:

http://www.sustainablenuclear.org/PADs/pad8301cohen.html

The salient point is still there; 5 billion years of U supply with no more than 1% increase in price over that time. Now there’s an inflation rate I can live with!

If we’re talking straight metal, U has a density of 19,050 kilograms per cubic meter (19 times denser than fresh water at 1000 kg/m^3). So, if we run the numbers:

32,000 tons U = 32,000,000 kg U;

32,000,000 kg / 19,050 kg/m^3 = 1680 cubic meters; let’s express that as a cube;

cbrt(1680 m^3) = 11.9 meters on a side; how about as a sphere;

(4/3) pi r^3 = 1680 m^3; solve for r -> radius of 7.37 meters, or a diameter of 14.75 meters.

Finally, 1 ton of uranium occupies v = 1,000 kg / 19,050 kg/m^3 = 0.052 cubic meters or 1.85 cubic feet.

Uranium is seriously dense! Though it doesn’t hold the record for normal solid-state density in the periodic table (it’s a toss up between iridium and osmium at 23,000 kg/m^3).

I wonder on how many other blogs there are comments with engineering unit conversions going on? :) Thanks for letting me dust off my brain!

Thanks for the heads up. I goofed up the file name and added an extra 0 in the link. I should work now.

Rod