METHOD OF CHEMICAL DECONTAMINATION OF NUCLEAR POWER PLANT EQUIPMENT Russian patent published in 2008 - IPC G21F9/00 

FIELD: power production.

SUBSTANCE: invention relates to nuclear power production and mainly, to chemical decontamination methods for radiation hazardous equipment of nuclear reactors and is intended for removing corrosion products on structural materials by means of chemical reagents solutions. Chemical decontamination method for nuclear power plant equipment includes two-bath oxidising and recovering treatment of equipment surfaces by water solutions of chemical reagents and their forced mixing at the given temperature and time. Equipment is decontaminated in the first bath in three stages. Two-stage decontamination is carried in the second bath. At stage 1, equipment is treated with water solution of potassium permanganate and acetic and nitric acids in the first and second bathes. Weight ratio of components is from 1:9:1 to 1:1:9. Solution with total acid concentration from 10.0 to 50.0 g/kg is made in the bath. Concentrated hydrogen dioxide is gradually introduced in the solution made in the first and second bathes. Concentrated solution of ethylenediaminotetraacetic acid with ammonium acetate and hydrazine at their weight ratio 1:0.5:0.1 is introduced to the first bath at the third stage. Solution of ethylenediaminotetraacetic acid with concentration from 10 to 50 g/kg and pH solution from 3.5 to 5.0 is made in the bath.

EFFECT: improvement of decontamination effectiveness and reduction of dose loads of NPP personnel.

3 cl, 5 tbl