-Z- (z@gundam.com)
Sat, 23 Dec 2000 15:15:02 -0800


> At 08:02 PM 22/12/00 -0800, you wrote:
> >What was being fused in your Physics fusion reaction example? The most
> >"traditional" or "normal" fusion reaction of which I'm aware is the
> >deuterium/tritium reaction:
> >
> >D (1H2) + T (1H3) -> He (2He4) + neutron + 17.6MeV (1 eV = 1.6022E-19
joules)
> >
> >By way of comparison, the helium-3/deuterium reaction used in Gundam yields
> >18.4MeV.
>
> Why was this picked? Was it because Deuterium and Tritium are readily
> available (Tritium by way of synthesis)
>
> Almost all fusion reactions nowadays need massive amounts of energy to
> maintain and are inefficient, so why D-T?

The first generation fusion reactors will use deuterium and tritium for fuel
because D-T will fuse at lower temperatures, around 100 to 200 million degrees
C. To date, no one has created a sustained D-He3 reaction -- He3 is terribly
hard to come by down here and the fusion temperature is three to five times
higher than that of D-T. So I guess the short answer to the question "Why D-T?"
would be that, for now, it's theonly game in town.

Deuterium can be easily extracted from seawater, where one in 6,500 hydrogen
atoms is deuterium. Tritium doesn't occur naturally but can most easily be bred
from lithium, which is abundant in the Earth's crust. Once the reaction is
established, even though it occurs between deuterium and tritium, the
consumables are deuterium and lithium. Ten grams of deuterium, which can be
extracted from 500 liters of water, and 15 grams of tritium, produced from 30
grams of lithium, would theoretically produce enough electricity for the
lifetime needs of an average person in an industrialized country.

By the way, deuterium used to be called "heavy hydrogen," so helium-3 is
sometimes called "light helium"....

-Z-

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