氧化还原法去污对核电站上充泵安全影响的试验研究

Experimental Study on Safety Effects of Redox Decontamination onCharging Pumps in Nuclear Power Plants

研究化学法去污过程中对核电站上充泵腐蚀量的影响。以马氏体不锈钢和奥氏体不锈钢为研究对象,分别进行氧化过程和还原过程中溶液浓度、反应温度、时间对腐蚀量的影响试验;之后进行了氧化还原全过程对两种不锈钢材料的腐蚀量影响试验;最后,对某核电站上充泵进行了实操去污工作。试验结果表明:在超声作用下,使用0.25%高锰酸钾+0.25%氢氧化钠混合溶液作为氧化剂、70℃反应4 h,然后再使用0.25%草酸+0.25%柠檬酸混合溶液作为还原剂、70℃反应2 h,马氏体不锈钢和奥氏体不锈钢样品表面主要为均匀腐蚀,平均腐蚀量小于1.5 g/m^2,腐蚀量满足相关标准要求,同时可有效去除上充泵表面的放射性物质。该配方和工艺流程可推广应用于核电站上充泵的去污工作。

Taking martensitic stainless steel and austenitic stainless steel,the main materials of charging pumps in nuclear power plants,as study objects,we respectively tested the effects of solution concentration,reaction temperature and time on corrosion in the oxidation and reduction stages of a REDOX decontamination process.The corrosion of both materials in the whole process was then evaluated.A practical decontamination operation on a charging pump was also carried out in a nuclear power plant.With 0.25%potassium permanganate+0.25%sodium hydroxide solution as the oxidant and 0.25%oxalic acid+0.25%citric acid mixture as the reductant,under the effect of ultrasonic,we had them reacted at 70℃for 4 h and 2 h respectively.It showes the steel sample surface is mainly of uniform corrosion,with an average corrosion amount of less than 1.5 g/m^2,which meets the requirements of relevant standards.At the same time,the radioactivity on the surface of the charging pump can be effectively removed.The formula and process can be applied to the decontamination of charging pumps in nuclear power plants.