The effects of Cr and W solute atoms on the evolution of irradiation-induced defects in Fe-8Cr and Fe-8Cr-2W alloys upon annealing after low-temperature neutron and electron irradiation were investigated by using positron annihilation lifetime measurements. Vacancy defects behavior at elevated temperatures showed that added solute Cr and W in Fe clearly suppress void growth. The void swelling suppression by Cr was explained using configuration-trapping model. For the W solute effects, the results of two types of irradiation support the solute and dislocation interaction model. Related results are important for the fabrication of improved radiation-resistant materials for fission or fusion reactors. (C) 2016 Elsevier B.V. All rights reserved.