Reduction of radioactive contamination of surface of steel structures of contour NPP equipment

Reduction in the rate of corrosion of constructional materials leads to increase in level of ensuring radiation safety at operation of NPS. It is possible to improve a radiation situation also due to decrease in sorption of radionuclides on the internal surfaces of the equipment. In this regard authors considered possible ways of decrease in sorption of radionuclides ⁶⁰Co and ¹³⁷Cs by a surface perlitny and alloyed their radioactivity, steely for the purpose of decrease. Results of experiments on sorption of radionuclides are presented and her communication with the size of equilibrium electrochemical potential is noticed. It is shown that sorption of Cs-137 honor 10 times more sorption Co-60. At transfer of steel to a passive state by passivation in nitric acid (pH = 3) considerable decrease in sorption of radionuclides ⁶⁰Co, ¹³⁷Cs (at 7-10 times) in comparison with not passivated steel is observed. Processing as alloyed, and perlitny steel of a zolyama of oxide of aluminum allows to reduce sorption of radionuclides in addition. Additive of colloidal solution - zoli Al₂O₃ in the passivating sour azotnonitratny solutions allows to increase considerably protective properties of the formed coverings and to prevent development of local types of corrosion (ulcers, pittings, cracking). (paper)