HOW I'D DO FUSION IF I RAN THE TRAVELLER UNIVERSE (and how humaniti would
do it if they could):
Nuclear Instruments and Methods in Physics Research Series A Volume 271,
1988, carried the proceedings of a conference on the theory of Aneutronic
Fusion Reactors (AFRs). Unlike Neutronic Fusion Reactors (NFRs) like the
deuteron-deuteron and deuteron-triton reactors being developed at Princeton
et alii, AFRs utilize a different sort of fusion reaction with different
yields and byproducts for more favorable results. An overview:
NUCLEAR FISSION: Fuel is enriched uranium 235/238
Waste is assorted uranium, plutonium, thorium
Reaction is: U+n=2 pieces+more n's
Easy to build and run
Fuel is costly and dangerous
Waste is radioactive and useless
Containment vessel becomes "hot" after a long time
Can be designed to make bomb-grade materials like plutonium
Some designs can runaway; all can melt down
Theoretical limit of efficiency: 33%
Requires heavy shielding during and after use
Power yield per ton: circa .001 MW
Smallest feasible reactor: not sure, it's used on subs.
NFR (D+D, D+T): Fuel is ordinary hydrogen or even water
Waste is ordinary hydrogen, water, some helium
Reaction is: D+D=alpha or D+T=alpha+n
Difficult to build and run
Fuel is commonplace and cheap
Waste is clean and harmless
Containment vessel rapidly gets VERY "hot", must be replaced
Can easily make bomb-grade materials like tritium
Primary hazard is meltdown, though it wouldn't be easy
Theoretical limit of efficiency: 50%
requires progressively more shielding as it runs
Power yield per ton: .01 MW
Smallest feasible reactor: 100 tons, 1 MW
AFR (the ideal): Fuel is either lithium-7 or (ideally) helium-3
Waste is helium
Reactions are: p+7Li=2alphas, 2x3He=alpha+2p NO NEUTRONS!
Extremely difficult to build and run
Fuel is somewhat costly but harmless by itself
Waste is clean and harmless
Containment vessel never gets "hot"
Cannot be used to make bomb-grade materials of any sort
Cannot runaway, explode or melt down
Theoretical limit of efficiency: 100% (85-90% easy)
NO SHIELDING NECESSARY, NO RADIATION HAZARD
Power yield per ton: 1 MW
Smallest feasible reactor: 1 ton, 1 MW
By "feasible" that means economically feasible for a TL 8 economy. Helium-3
is one tenth the cost of Uranium, and one kilogram-equivalent of the stuff
would give power equal to that obtained by burning 100 metric tons of refined
fuel oil. If we extrapolate efficiency increases and shrinking lower limits,
we get down to the manpack fusion piles of TL 13 and up. They're cheap to run,
environmentally safe, don't make a mess, tremendously efficient, and are
perfect for civilian use because they can't be converted to weaponmaking.
Not bad, eh? So what's the catch? Simple: they require operating conditions
an order of magnitude more difficult than the ones Princeton's been trying
to reach for decades now. But with grav plates, it might be possible.
What would this mean in Traveller terms? Well, power plants would become tiny
and power worries would vanish; wilderness refueling would become impossible
under most circumstances (or can you get helium from a gas giant?); refined
fuel would be a lot less dangerous (liquid helium can't explode) but more
costly (liquid helium is tough to keep liquid), and there wouldn't be any such
thing as unrefined fuel any more. And other game-balance-altering effects as
well, but those will do for a start. (No, they won't be put in TDR if i can
help it: the rules are enough of a mess as it is.)
Just a little something to chew on for those of you who wanted to see what an
"Advanced" culture would do for power (assuming we don't discover dilithium
crystals and antimatter any time soon)....
metlay
PS. Note the power plant efficiency: 1 MW for 100 tons weight for fusion,
unless i got my numbers crossed. How's that compare with the rules?