放射性废液蒸发器除垢方案设计及验证

针对放射性废液蒸发器处理能力短时间内明显下降,采用郎格利尔指数(LSI)等方法,对蒸发器结垢和腐蚀趋势进行了判断;重点分析了p H、蒸发温度、Ca2+浓度、原液流速对蒸发结垢速率的影响。结果表明:蒸发原液已具备结垢和腐蚀趋势,p H等因素改变增加了蒸发器结垢速率,结垢后蒸发器蒸发强度下降75%。借鉴民用蒸发器常用除垢方法,结合核行业蒸发器除垢具有的放射性安全要求,设计了一套放射性废液蒸发器浸泡式酸性除垢方案,用氨基磺酸进行除垢试验;经实际验证:该方案安全可行,除垢效果明显,除垢后蒸发器处理能力恢复至原设计值0. 6 m³/h。

Design and verification of a descaling scheme for radioactive waste liquid evaporator

In view of an obvious decline in processing capacity of radioactive liquid waste evaporator in a short period of time,the method of Langelier Saturation Index( LSI) was used to judge the scaling and corrosion tendency in the evaporator. Effects of pH,evaporation temperature,Ca2+concentration and stock solution flow rate on evaporation scaling rate were analyzed. The results show that the evaporation liquid has the tendency of scaling and corrosion. Variations of pH and other factors increase the scaling rate of the evaporator. After scaling,the evaporation intensity of the evaporator decreases by 75%. An immersion acid descaling scheme for radioactive waste liquid evaporator was designed, based on commonly used descaling methods for civil evaporators and combining with safety requirements of nuclear industry evaporators. It has been verified by experiments that this scheme is safe and feasible. The descaling effect is obvious,and the processing capacity of the evaporator has restored to its original design value of 0.6 m^3/h after descaling.