Energy multiplication and fissile fuel breeding limits of accelerator-driven systems with uranium and thorium targets

The neutron spectrum maximum is by ∼1 MeV. Lower energy neutrons E < 1 MeV have major contribution on fissile fuel material breeding (>97.5%), whereas their share on energy multiplication is negligible (0.2%) for thorium, depleted uranium. Major fission events occur in the energy interval 1MeV < E < 50 MeV.