The main advantage of fission reactors with neutron illumination is that, owing to the neutron illumination, they operate in the subcritical mode and, hence, are safe. Neutrons required for the illumination are generated during nuclear fragmentation in a target irradiated by 1–2 GeV protons. A substantial disadvantage of this method for energy generation is the severe restriction imposed on the power of a plant. This restriction is due to the restriction imposed on the intensity of an accelerated-proton beam by the tolerances for the activation of accelerator structural elements. The substitution of heavier nuclei (from carbon to argon) for protons is shown to substantially increase the intensity of an accelerated-ion beam and to provide a commercially reasonable thermal power of ∼4–6 GW.