PUREX流程1A槽中锝的走向分析

结合基础研究数据和工艺实验数据，对核燃料后处理PUREX流程共去污槽（1A槽）中锝的走向进行了分析。工艺实验数据表明：1A槽萃取段中TBP对锝与锆的共萃取行为是影响锝走向的主要因素。硝酸浓度会显著影响TBP对锝与锆的共萃取性能，当c(HNO₃)＜3 mol/L时，提高硝酸浓度可以促进水解的锆解离生成Zr⁴⁺，从而促进锆锝共萃取；当c(HNO₃)≥3 mol/L时，硝酸可能会参与锆与锝的萃取。在0.5~5 mol/L的范围内，提高硝酸浓度有利于锝的萃取。在1A槽洗涤段硝酸浓度分布相近的条件下，1A槽中锝的走向取决于萃取段硝酸浓度的分布。萃取段硝酸浓度分布不同，将导致进入1A槽有机产品液（1AP）的锝含量比例不同，萃取段硝酸浓度越高，越有利于锝进入1AP。

Distribution of Technetium in 1A Tank of PUREX Process

The distribution of technetium in the co-decontamination tank (1A tank) of PUREX process was analyzed. The trend of technetium was determined by the co-extraction of Zr-Tc in the section of extraction, which is related with the distribution of nitric acid. The concentration of nitric acid shows significant influence on the co-extraction of technetium and zirconium. At c(HNO₃)<3 mol/L, the concentration increase of nitric acid prevents the hydrolysis of Zr⁴⁺ to promote the co-extraction of Zr-Tc. At c(HNO₃)≥3 mol/L, nitric acid is co-extracted with Zr-Tc. At the range of 0.5-5 mol/L, the nitric acid is in favor of the extraction of technetium. The higher nitric acid concentration makes more technetium to be extracted into organic stream in PUREX process.