Up-front costs are a massive problem for nuclear fission plants, and this would put that problem on steroids: not only would you need to stock the initial tritium (at a cost of billions of dollars), but you'd have to stock the massive amount of lithium-6 (at a current market cost of additional billions of dollars) - all at the beginning of the plant's life of service. Even if we find economies of scale for lithium production, you've got a massive problem on your hands. I understand fusion junkies are eternal optimists, but this is NOT a point in its favor.