When to stop refuelling

In TML Nightly V47#4, Leonard Erickson [email removed] writes:
>So we have 1e6 x 1e6 = 1e12 tons of hydrogen leaving annually.  Water
>is H2O.  By weight it's 1/9 hydrogen, 8/9 oxygen. [...]

Ah, but protium (hydrogen-1, the most common isotope) is useless for
fusion unless you use a carbon-nitrogen cycle or some such.  Straight
hydrogen fusion requires deuterium and/or tritium.  Anyone got figures
on isotope frequencies? I don't have 'em handy...but I'll bet that less
than 1 in 100 atoms of hydrogen is "good" hydrogen.  This multiplies
volume by 100, making it a hefty 9.3 cm decrease in ocean level,
annually.  This will have some significant effects after a while.

Seth "the Lesser"


Seth L. Blumberg          \ Sturgeon's Law: 90% of everything is crap.
[email removed] (play)   \  Blumberg's Corollary: And the rest ain't so
[email removed] (work) \        hot, either.
   > No one I know shares my opinions, least of all Columbia University. <