This topic has been touched on breifly before. I sat down this morning with
Mark's Handbook of Mechanical Engineering (remember that I am a chemical ^H
engineer by training) and read carefully through the section on nuclear power.
Since I have commented on usage rates of nuclear fission fuel in the past, I
felt that I should look things up to see what was really what. If I am reading
the numbers correctly, and using the density of fuel as given in the referee's
manual, and assuming that we are using this fission pile to generate electricity
by steam turbine, and assuming that we are using fuel enriched to 5% fissionable
material, burning it dwon to 1% fissionable material, and that you achieve a
30% efficiency on conversion of heat released to electrical energy (reasonable),
it would appear that your fuel consumption should be about .0013 kl/year/MW.
My first guess, to make things come out right, was to assume that the number
given, .003 kl/MW was per year, which looks like it wasn't a bad guess.
This means that in order to keep fusion competitive, we really need to increase
its fuel efficiency by a couple of orders of magnitude.
I was reminded of this when the latest issue of Challenge (#47) came this
weekend, with two short adventures using low tech level spacecraft designed
per the rules in Challenge #45, and the nuclear fuel outweighed the ion
reaction mass in the ion drive module by a factor of 30 or 40 to 1.
Rob Dean
(So apart from the Armor 40 argument, and the fusion rocket argument, the
ships I have uploaded using Charles Gannon's low-TL space design sequence
have been reasonable.)