METHOD FOR WASHING A STEAM GENERATOR Russian patent published in 2007 - IPC F28G9/00 

FIELD: nuclear and thermal power engineering, possible use for restoring serviceability of steam generators and other thermal power engineering equipment by means of chemical washing.

SUBSTANCE: method includes sequential three-stage processing of working surfaces of steam-water hollow of steam generator by water solutions in forced stirring mode, at which during first and third stages ammoniac solution of ammonium salt of weak organic acid is used with concentration of 5-50 g/kg and hydrogen peroxide with 1-5 g/kg concentration, and at second stage a solution is used consisting of ethylene diamine tetra-acetic acid, ammonium salt of weak organic acid and hydrazine with weight ratio of components 1:0,65:0,1, respectively. After draining of solutions used during first and third washing stages, regeneration of solutions is performed by precipitating hydroxide or oxide of copper in them, dividing the sediment and growth solution and injecting admixtures into growth solution and then returning regenerated solutions into washing cycle of other steam generators of power unit.

EFFECT: decreased volumes of liquid toxic wasters and energy costs required for their reprocessing; decreased flow of distillate required for performing power unit steam generator washing operations; decreased probability of migration of copper into natural waters in the region near a nuclear power plant.

6 cl, 5 tbl