Normally with nuclear power you use the heat generated to drive a heat engine of some sort with strict limits on the theoretical efficiency. But many pulse fusion designs look at using the momentum of emitted charged particles directly through their interaction with magnetic fields at far higher efficiency than could be achieved with the energy going through a heat stage. Carbon-14 emits only beta particles which are, of course, all negatively charged. I wonder if they've managed to turn those into a very high voltage, very low current continuous source directly?