High-Energy Fuel Ion (HEFI) populations are created in plasmas subjected to Neutral Beam (NB) injection and Ion Cyclotron Resonance Heating (ICRH). These heating schemes were tested at JET in the DTE1 and TTE campaigns and diagnosed with the help of Neutron Emission Spectroscopy (NES). The JET experience can be transferred to burning plasma studies on ITER but for suitable rescaling including differences in plasma size and conditions, besides machine operating parameters. The main differences are that ITER NB will use 1MeV tangential D beams (compared with 130keV at oblique angle in JET) leading to d deposition into circulating orbits with a pitch angle about 30o. ICRH will use different heating schemes including some resonating with T or D as tested on JET and shown to produce HEFI populations with pitch angle 90o and "tail" temperatures T^ 100keV depending on power density conditions. Other sources of HEFI populations of both d and t of up to 3MeV are the a + d and a + t knock-on collisions, which give rise to a so-called Alpha Knock-on Neutron (AKN) signature in the emission spectrum. With ITER temperatures in the 20keV range, the AKN would make about 10-3 of the total emission compared to 10-5 for JET.