The present parametric study formulates certain requirements regarding basic determinants of the only really economically effective variant of fusion power - the fusion-fission hybrid. On the basis of performed calculations and considerations the conditions are determined to be fulfilled for the realization of a competitive hybrid reactor. In spite of the still existing wide margins of uncertainty of pertinent physical data the carried out comparison of the fusion hybrid with the pure fusion variant has come out firmly in favour of the former. Thus, the indicated difficulties notwithstanding, the promising perspectives of fusion breeders have been strengthened.