[WorkLobster]

> you would need 100% efficiency to be able to breed your own tritium

How so? As I understand it, the breeding reaction is exothermic (Li-6 + n -> He-4 + T) so all you need are neutrons, for which (as someone pointed out to me two years ago[1]) neutron multipliers would be used.

[1] https://news.ycombinator.com/item?id=32224650

[credit_guy]

I was talking about the neutron efficiency, not the thermodynamic efficiency.

As for neutron multipliers, they are currently so far from being realistic that they are essentially science-fiction.

[WorkLobster]

I'm not sure I understand what's 'science-fiction' about lead or beryllium?