The effects of nickel and/or zinc addition on microstructural evolution in copper under electron irradiation have been investigated to study possible effects of solid transmutants generated in copper and copper alloys by fusion neutrons. Radiation-induced dislocation density increased with increasing nickel content but was independent of zinc content during 1 MeV electron irradiation. An enrichment of nickel and a depletion of zinc at grain boundaries occurred during irradiation. Measurements of temperature and damage rate dependences of saturated dislocation loop density showed that the interstitials are deeply trapped by nickel clusters forming loop nuclei in alloys containing nickel. It was shown that clusters of nickel as a solid transmutation product can affect strongly the dislocation evolution and related properties of copper and copper alloys by trapping interstitials from relatively initial period of fusion reactor operation. On the other hand, the effects of zinc production seemed to be small, althogh possible interactions with vacancies were suggested.