Lithium is about 92.5% Li-7 and 7.5% Li-6; Li-6 can be fairly easily enriched due to the high percentage of mass difference. Lithium has at least two reactions with Deuterium: Li-6 + H-2 = 2He-4 + 22.4 MeV Li-7 + H-2 = Be-8 + n + 15.1 MeV The reaction of interest would be with Li-6, so as to eliminate neutrons which could serve to produce unwanted radioactive wastes. How feasible would it be to shoot a high energy [a few MeV] Li-6 beam into heavy water [D2O], and would the energy release [extracted from boiling water by traditional heat extraction methods] from fusion be enough to power the Lithium ion beam accelerator? As a corollary, what window in a heavy-water vessel should be used through which the Lithium beam should be sent that would minimize beam-energy loss while maintaining adequate strength to contain boiling/pressurized water? Would the Oxygen in the D2O significantly interfere with the reaction? Could pressurized D2 gas be used instead if Oxygen significantly interferes?
It would depend on the cross-section for interaction. I'm not certain about that for O-16. You could possibly keep the beam energy, after the ions in the beam transit the window with some energy loss, sufficiently high for surmounting the coulomb barrier for H-1 [1 proton], but insufficient for 8 protons [O-16], to avoid an unwanted nuclear interaction with the Oxygen nucleus. The thinner the window the less the energy loss of the ion beam in transit. Here's possibly the better reaction: Li-7 + H-1 = 2He-4 + 17.3 MeV Less energy produced, but you don't have to mess around with getting heavy water [not that hard, but getting both hydrogens as H-2 is required. Getting heavy hydrogen gas is easier]. Also, you can use the more abundant isotope, but that is not a critical factor, as Li-6 is relatively abundant, and easy to separate from Li-7 in an ion beam that traverses a magnetic field. What's nice about both of those is that the waste product is Helium - nice and clean! So, how hard would it be to make an ion-beam accelerator that continuously accelerates Lithium ions. The window that they would have to go through into the vat of fusible material [H-1 or H-2] could be tiny [1 millimeter diameter or thereabouts] so could be quite thin - possibly aluminum, or other metal, or silicon-dioxide; need some materials science work done here at the nuclear level. The window needs to be thick enough to withstand the pressure generated in the vat so it doesn't rupture, and internal nuclear reactions that over time would serve to weaken/embrittle it.
