In terms of supply, when dealing with fusion neutrons, how significant would it need to be to generate a reaction of that scale?
Discussion
It would be sweet to get 1:10 fusion:fission, burn-up would be a completely different game; but even 1:10000 allows the designer to remove the external neutron sources and improve the responsiveness of the reactor.
China is where it's at on innovation. Would have sounded ridiculous to say that 20 years ago, but here we are...