[Telepathic Intruder]

One good thing about using tritium is that you can line the reactor wall with lithium and breed more tritium by neutron bombardment, and there's plenty of lithium around, as opposed to helium-3.

[bagman]

The problem is that one tritium atom is produced for each neutron absorbed. The fusion reaction produces only one neutron. Therefore, we will see a net decrease in tritium if any neutrons are not absorbed by a lithium atom (I guarantee that some neutrons will not be absorbed by lithium atom) or if we are unable to recover 100% of the tritium from the blanket (I know of no chemical processes with a 100% recovery rate).