As I read it extra loose neutrons help and extra energy is crucial.
Statistical variations in individual deuterium nuclei would result in a few ‘hot’ ones colliding. That would give sporadic results. Which, oddly enough, is what is observed.
Could the bell curve of energies be shifted a bit higher with focused acoustic energy? I’m thinking something like a lithotripsy machine, pinpoint delivery of enough energy to break up kidney stones, still below the 8 orders of magnitude needed, but if it shifts the curve, more nuclei would ‘be over the cliff’.
Adding neutrons with a External Neutron Initiator “hair drier”? hmmm...