[en] The method for simulation of the processes of formation of depositions and corrosion of the surface of steam generator heat exchange tubes which permits to determine the heat exchanger interwashings period is suggested. The method is based on bypassing of the steam generator nutrient medium through a tubular indicator with heating of the latter by steam produced by the steam generator and control of the indicator surface state. The control of the indicator surface state is realized by means of the replaced ampoule with the radioactive emission source or by measuring the temperature of the vessel wall by thermocouples