Fusion

This is double-talk, but it's grounded in half decent science.

Fusion power plants for space vessels...

What to use for fuel?

The standard GURPS fusion plant comes with a self-contained fuel supply that lasts 200 years.

Traveller's plants use a LOT of hydrogen and appear to utilize bog standard {H + H -> He + energy} reactions.

Erin's plinking around with the Traveller plants got me to thinking.

Her ammonia for deuterium storage solution to a problem was unique.  Deuterium fusion gives more energy than the protium reaction.

But ammonia is nasty stuff.  What you may be thinking of as ammonia is the household cleaner, which is a solution in water, not the pure stuff you'd want to use for fuel.

The standard Traveller assumption of using plain old hydrogen means that we're going to need some serious pressure and/or cryogenics to store it.  This is in addition to its tendency to evaporate through anything that can hold it.  The fire risk isn't really worth mentioning since this is space and a rupture will most likely be to vacuum not air.  Gas detectors exist today that could be installed just in case of a leak into the life system.

My solution to the problem is water.

We make our fusion plant run a breeder cycle.

Step one is to separate the hydrogen and the oxygen.

Step two is to blast the hydrogen with neutrinos neutrons we've obtained by running a bit of H+Li reaction on the side.  This gives us deuterium or tritium depending on our needs.

Step three is the main fusion cycle.

Step four, tear a neutrino neutron off the resulting He and run it back through!  He3 fusion is one of the best energy outputs speculated.

Step five, keep recycling the resulting elements until output drops.  I don't have the math to figure that out.  In a star the reaction is energy positive until it starts to fuse iron.  It's likely that the most economical point is well before iron though.

Our theoretical plant should run better than a star since we're engineering the inputs and controlling the cycle.

I tend to favor the GURPS answer for a self contained unit because the people working on the idea there did it more than 20 years after GDW and we have a better understanding now.  In 1977 fusion was a theoretical science problem, today it's an engineering problem.  The work done on Transhuman Space reinforces the original work.

You should see the numbers bandied about with the GURPS plant and you start to wonder what all that hydrogen is being used for in Traveller.  One idea put forward is the fuel consumption on a Traveller power plant is mostly dumping it overboard to cool the system.  The authors have not addressed it, which means that they prolly didn't consider it, fuel consumption was for game balance and flavor; no doubt.

Just for fun:  Assuming the Traveller reaction is a Deuterium Deuterium reaction.  The Type S power plant is a 72.21 Megawatt unit.  Assuming I did the math right...  It'd be 72.21 Mw if it used 1kg of Hydrogen in 28 days.  It's 722.11 gigawatts for 20 tons of fuel.