Interesting. Would you have heat exchangers to capture the energy of the D2 + D2 reaction in addition to the direct proton capture from the D2 + He3. The heat exchange was one major issue I saw when using such a small device.
(edit see my post below)
That is why I liked the pure He3 + He3 Reaction. Twice the number of protons and a estimated capture of 95% of the energy. If you can trick your way around the coulomb barrier (like the cold fusion people tried to do) you can get a ton of energy from a very small package.
I could not come up with a source for the He3 without going to the moon so I guess there would have to be a breakthrough in Li6 -> T3 -> He3 conversion. If you could convert one of the Li6 neutrons to an anti-neutron you might get spontaneous decay to T3 (in addition to the antimatter reaction). Then you just need to figure out how to reduce the half life to a more manageable timeframe.
Yes this involves a lot of handwaveium, but is on a believability level as Star Trek science IMO (I stole the creation of the anti-neutron conversion from the startrek tech manual).
Well, if I had all the answers I would be at fermilab right now
(and a billionaire
)