针对不锈钢表面^(60)Co污染的电化学去污研究

Study on Electrochemical Decontamination of ^(60)Co Contamination on the Stainless Steel Surface

核设施退役与三废治理过程中会产生大量表面被沾污的不锈钢金属部件,作业环境和人员将面临潜在的放射性污染和受照剂量问题。针对不锈钢金属表面的^(60)Co污染问题,设计了手持式电化学试验装置对不锈钢表面污染进行合理有效的原位去污;采用正交实验法优化电解液浓度、电流密度和电极间距等电化学工艺参数,并对不锈钢表面^(60)Co污染进行去污验证。研究结果表明,本文建立的电化学原位去污方法具有去污时间短、效率高等优点;在电解时间为30 s、电解液为10 mol/L硝酸、电流密度为0.3 A/cm^(2)、电极间距为0.4 cm的条件下,此方法对不锈钢表面^(60)Co污染的去污效率可达99.9%以上,腐蚀深度大于10μm,可使污染降低至环境本底辐射水平。

During the decommissioning of nuclear facilities and the‘three wastes’treatment,a large number of stainless steel metal parts will be produced,and the working environment and personnel will face the problems of potential radioactive contamination and exposure dose.Aiming at the problem of ^(60)Co contamination on the surface of stainless steel,a portable electrochemical test device was designed to remove the contamination on the surface of stainless steel effectively.The orthogonal experiment method was used to optimize electrochemical process parameters such as electrolyte concentration,current density and electrode spacing,and to verify the decontamination of ^(60)Co contamination on the surface of stainless steel.The results show that the electrochemical insitu decontamination method established in this paper has the advantages of short decontamination time and high efficiency;Under the conditions of electrolysis time of 30 s,electrolyte of 10 mol/L nitric acid,current density of 0.3 A/cm^(2) and electrode spacing of 0.4 cm,the decontamination efficiency of this method for ^(60)Co contamination on stainless steel surface can reach more than99.9%,and the corrosion depth is more than 10μm,which can reduce the contamination to the environmental background radiation level.