[en] The paper reviews the radiation damage phenomena in metals after light element irradiation, in particular helium. The irradiation-induced defects, the microstructural damages associated, and the changes in mechanical properties induced are discussed in terms of the homologous temperature and the CTR-parameter combining the amount of atoms injected and the amount of damage created. Particular attention is paid to the atomistic approach to describing small-size effects. Large-size effects, currently created in a phenomenological manner, are discussed in the last section and the phenomena of gas re-emission, gas bubbles in the bulk and surface bubbles are considered in some detail. (orig.)