[en] Irradiation of silicon containing perfect dislocations and Frank loops is carried out 'in situ' in an electron microscope at 200 keV and T = 20 to 1000 ⁰C. The formation of aggregates of interstitial atoms as rod-like and (113)-defects is established at T = 20 to 600 ⁰C. Irradiation does not result in dislocation climb in this temperature range. Transformation of perfect dislocations to helical configurations and growth of Frank loops are observed at T >approximately 600 ⁰C. The dependence of the climb rate of the loop segments on the temperature, the irradiation intensity, the depth of the dislocation segment, and the thickness of irradiated crystal is measured. The data on the climb rate of the dislocation segments in the vicinity of silicon surface in comparison with the Si-SiO₂ interface are discussed. (author)