METHOD OF CHEMICAL DECONTAMINATION OF NUCLEAR POWER PLANT EQUIPMENT Russian patent published in 2008 - IPC G21F9/28 

FIELD: power engineering.

SUBSTANCE: invention is related to the field of nuclear power engineering and is intended for removal of operational radioactive deposits from the surfaces of nuclear power plant (NPP) primary circuit equipment. During chemical decontamination single-bath three-stage treatment of equipment surfaces is carried out with water solutions of chemical reagents at preset temperature and pH of solutions in the mode of their forced mixing. At the first stage oxidizing nitric acid solution of potassium permanganate with acetic acid addition. Ratio of components in solution KMnO₄:HNO₃:CH₃COOH makes from 1:9:1 to 1:1:9, accordingly, based on estimate of solution creation in bath with total concentration of acids of 10.0 g/kg and initial pH in the range from 1.0 to 2.5. At the second stage concentrated hydrogen peroxide is introduced into bath solution, at the third stage - concentrate of solution of ethylene diamine tetraacetic acid with ammonia acetate and hydrazine at their weight ratio of 1:0,5:0,1, accordingly, on the basis of creation of solution in bath with concentration of ethylene diamine tetraacetic acid from 10.0 to 50.0 g/kg and pH of solution in the range from 3.5 to 5.0.

EFFECT: conditions of operational radioactive deposits solution are improved, secondary deposits sedimentation is eliminated, decontamination efficiency is improved, dose loads to NPP servicing personnel are reduced.

2 cl, 4 tbl