In order for a neutron source to be a proliferation risk, it also has to be a power source. At least if you want to transmute enough stuff under a few 100 years anyway.
We can run some basic numbers. Lets assume DD fusion with full T ash burn and no He3 burn. Thus we have
DD->T +p, DD->3He +n, DT->4He+n
total reaction is
5D->3He+4He+2n+p 24.9MeV (16.5 MeV in neutrons)
So if we want to get 7kgs of Pu from 238U we need about 30 moles of neutrons assuming 100% efficiency. To do this in one year you need a average power of 1.1MW. Definitely not just a neutron generator.
EDIT: i forgot the not unsubstantial power from the transmutation itself.
