Re: Getting the energy out
Actually this is solved at the same time as the tritium breeding problem. The fusion reaction currently envisaged is deutrium-tritium fusion. Tritium is not a naturally occurring element so it has to be bred by neutron bombardment of lithium. This reaction has a reasonably high cross section so it can absorb a fair number of neutrons and produces tritium and helium which then stop fairly rapidly in solid materials depositing all the original neutron energy. The net result is that the lithium blanket heats as it generates the needed tritium, and the heat can be recovered in fairly conventional ways.
Designing these blanket systems is a fairly big engineering problem, but it's almost certainly solvable once we've got a self-sustaining fusion reaction to go in the middle.