[en] Iron based model alloys and 316 stainless steel type pure Fe-Cr-Ni alloys modified by additional elements were electron and carbon ion irradiated in order to investigate solute segregation and the effect of additional elements for retardation of the segregation. The solutes concentration change were recognized during irradiation depending on size effect, but when interstitial impurities which interact strongly with solute atoms were contained, segregation phenomena the size-effect dependent were suppressed. The segregation could be suppressed by adding large oversized additional elements and this was explained according to a reduction of the effective absolute point defect concentration. (author). 14 refs., 10 figs