“No. The math doesn’t work out, actually. It gets you close to 1 Tritium bred per fusion created, but it assumes 100% of neutrons go to breeding and it assumes no losses due to hydrogen diffusion into metals, pump losses, etc.”
Studies show 1.14 TBR for blanket alone.
Thank you for the article. I have read it, and here is the problem. A TBR of 1.14 for the blanket is a problem because that is an ideal breeding ratio before you account for loses in the process of actually extracting the tritium from the blanket and using it some time in the future. Remember tritium is a form of hydrogen which diffuses wonderfully through most materials. Losing >>10% in pumps, vacuum walls etc. is expected. While it is unclear, it seems that the author has also imposed an unphysical boundary condition on his presumed neutron reflectors at each boundary.
But fundamentally, the problem is that a theoretical ideal breeding ratio of 1.14 is woefully insufficient when real world practicalities of losses in processing, transfer and Tritium decay are accounted for.
Which is the point. There isn't another source of breeding so to get that 1.14 all fusion neutrons have to reach the blanket and all tritium that is breed has to be extracted.
Oh, there is another huge loss - which is that the plasma loses tritium to the first wall, to vacuum pumps etc. Only a fraction of the tritium in the plasma ever fuses to produce the neutron for which breeding happens in the first place. And recovery of that lost tritium is certainly less than 100%.