[joak]

I'm not aware of He3 easily becoming T. I know T spontaneously becomes He3 (emitting a positron and a neutrino) with some probability, a very low one, not relevant at the scale of a pulse

[moloch-hai]

I am wrong. To absorb an electron would need a coincident neutrino.

Instead, a neutron strikes ³He producing T, H and a photon.

[pfdietz]

Yes, and that's not a problem either here, because the neutrons don't stick around. If you had a lithium blanket making T you'd want to clear out any 3He as it was produced from T decay so they don't hoover up too many thermalized neutrons, though.

I don't think that (n,p) reaction on 3He normally produces a photon, btw.

[moloch-hai]

I suppose the 764 keV could be kinetic:

  n + 3He → 3H + 1H + 0.764 MeV

I expect the concentration of ³He in your blanket would be extremely low, relative to the Li, so an unlikely target.

Really, if it takes neutrons, it is not a problem.