碘-129在环境介质中的化学形态与迁移特性研究

项目名称： 碘-129在环境介质中的化学形态与迁移特性研究

项目编号： No.11275147

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 赵耀林

作者单位： 西安交通大学

项目金额： 90万元

中文摘要： 本项目基于超灵敏的加速器质谱技术，开展核燃料后处理和高放废物地质处置等核活动释放的长寿命放射性核素碘-129在相关环境介质中的化学形态与迁移特性研究。通过碘-125示踪技术，定量分析阴离子树脂交换吸附、银粉吸附、共沉淀和逐级浸取等方法中洗脱液浓度和过柱速度、银粉颗粒大小、氯离子浓度和浸取温度等参数对碘回收率和分离效率的影响，建立起环境样品中不添加任何载体的碘-129提取制样方法和化学形态分离方法。在此基础上，通过贯穿扩散实验，研究碘-129在膨润土、花岗岩等环境介质中的吸附、扩散行为，获得表征碘-129迁移属性的有效扩散系数、容量因子和分配系数等关键参数。同时结合实际应用需求，开展碘-129在真实环境湖水、土壤等中的迁移扩散研究。对比获得的碘-129的迁移扩散数据和国际上已有的碘-125的数据，分析其迁移规律的异同。研究可为我国核燃料乏燃料科学安全地处理与处置提供重要的基础数据和理论指导。

中文关键词： I-129；形态分析；无载体制样；高庙子膨润土；迁移

英文摘要： Iodine-129 is the only long-lived isotopes of iodine with a half-life of 1.57×10^(-10) year. Its chemical speciation and migration in environmental media related to nuclear fuel reprocessing and high-level radioactive waste disposal is investigated by highly sensitive accelerator mass spectrometry. Through research on the absorption of iodine on anion exchange resin, absorption of iodine molecule on silver powder, AgCl-AgI coprecipitation, and sequential extraction technology, the influence of concentration and flow velocity of eluent, diameter of silver powder, concentration of Cl anion, and time needed for dissolution on recovery of iodine or separation efficiency of various iodine-129 speciation is analyzed quantitively by using iodine-125 as a tracer. The method used to prepare sample or to separate various speciation of iodine-129 in environmental sample is established without adding any iodine-127 carrier. Furthermore, the diffusion and sorption behavior of iodine-129 in bentonite, granite or other medium is studied by a through-diffusion experiment. Several key parameters for iodine-129 migration are determined, such as effective diffusion coefficient, rock capacity factor and distribution coefficient. Meanwhile, combined with the need for practical application, the migration of iodine-129 in lake water a

英文关键词： I-129；Speciation analysis；Carrier-free sample preparation；GMZ bentonite；Migration