“The calculated local TBR in the present design reached 1.4 or more in the Li-Pb breeder with a sufficient thickness of the breeding zone.”
I am not going to argue this further. First, we don’t have any demonstrated scheme for getting fusion anywhere except bombs and astrophysical objects so the practical engineering aspects are kind of irrelevant.
Second, there are a lot of practical engineering issues that must be overcome including the demonstration of a scheme for breeding tritium with a sustainable system cycle gain > 1. Not just a blanket design, but the whole system.
Fusion is very very different from fission. Fission reactors work well in cylindrical geometries, which means that engineering is straightforward [cold water in one end, hot water out the other, fuel elements that can be inserted and withdrawn as bundles in a linear fashion, easy instrumentation, etc.]. Nuclear physicists keep trying to design spherical fission reactors, but from an engineering standpoint, excepts for some very specialized applications, they are a practical disaster. Fusion physics doesn’t like cylinders. It seems to prefer spheres for laser fusion, or toroids for magnetically confined fusion, which cause endless engineering nightmares.
But we needn’t worry about the engineering part because no one has yet made the physics part work.