Heat treatment of the weld of the steam generator is investigated in this paper. Annealing is realized by system of heating elements that are placed on casing of the generator. An experiment using real parameters and a computational fluid dynamics analysis using COMSOL Multiphysics software were performed. Experimental data were compared with results of the analysis. Boundary conditions for numerical prediction had been derived on basis of results obtained from a supplementary calibration experiment. There was good correlation between predicted and measured data. Based on results it can be stated that 67 heating elements with heating output of 60-70 % of maximum range is sufficient number for required heat treatment.