METHOD OF CHEMICAL DEACTIVATION OF NUCLEAR POWER PLANTS EQUIPMENT Russian patent published in 2008 - IPC G21F9/28 G21F9/30 

FIELD: nuclear power engineering.

SUBSTANCE: in process of chemical deactivation double-bath oxidising-reducing treatment of equipment surfaces is performed with aqueous solutions of chemical reagents in the mode of their forced mixing at preset temperature and time. In the first bath surfaces are treated with aqueous solution of potassium permanganate with acetic and nitric acids. At that initial PH value of solution makes from 1.0 to 2.5. Ratio of components is maintained within the limits from 1:9:1 to 1:1:9. On completion of oxidising treatment excessive potassium permanganate and deposits of manganese dioxide are destroyed with hydrogen peroxide. In the second bath treatment is performed with aqueous solution of oxyethylidenediphosphonic acid with hydrazine. Ratio of components makes 1.0:0.25. At that initial PH value of solution is not less than 3.5, solution pH is corrected with ammonia.

EFFECT: makes it possible to increase efficiency of deactivation, to reduce radiation doses on NPP service personnel, to reduce amount of produced liquid radioactive wastes.

3 cl, 4 tbl