On the basis of the energy and angular spectra of particles emitted from the lateral surfaces of light element targets, the energy balance of a mesocatalytic hybrid reactor (MCHR) has been estimated, with the dependence upon fuel enrichment, type and volume fraction of coolant in the mesocatalytic and electronuclear channel blankets taken into account. It is shown that it is possible to generate a considerable amount of electric power in an MCHR due to burning up fissile nuclides in an MCHR blanket by choosing appropriate types of fuel composition and coolant. Despite some reduction of the fissile nuclide breeding ratio and of the number of nuclear reactors (NR) in the MCHR-NR system, the primary beam power gain is of the same magnitude as in the case of a natural uranium blanket with a hard neutron spectrum. A simplification in solving ecological, economic and safety problems in nuclear fuel reprocessing can be reached by burning the accumulated fissile nuclides directly in the MCHR blanket