摘要
237 Np是高放废物地质处置库安全评价中的关键核素之一，其环境化学行为受到人们的重视。本工作利用化学种态分析软件CHEMSPEC计算了Np在北山地下水中的溶解度，并研究了氧化还原电位Eh值、pH值、总碳酸根离子浓度等对溶解度的影响。结果表明，Np的溶解度范围为8.19×10－8～3.29×10^-3 mol／L。Eh值对溶解度的影响最为显著。当Eh＝0.089 V或更小时，Np的沉淀为NpO2，溶解度较小；当Eh＝0.346 V或更大时，Np的沉淀为NaNpO2CO3或NpO2OH ，溶解度较大。Np的溶解度随pH值的变化趋势与其沉淀形式密切相关。当pH＝7.25时，对于NpO2和NpO2OH沉淀，增加总碳酸根离子浓度使得Np的溶解度增加；对于NaNpO2 CO3沉淀，增加总碳酸根离子的浓度会使 Np的溶解度降低。
237 Np is one of the key radionuclides for the safety assessment of high‐level radioactive waste repository .The environmental chemistry of neptunium is concerned . In this work , the solubility of neptunium in Beishan groundwater was analyzed by CHEMSPEC .The influences of redox potential Eh ,pH ,and the total carbonate con‐centration on solubility were investigated .The results indicate that the solubility range of neptunium in Beishan groundwater is 8.19 × 10-8‐3.29 × 10^-3 mol/L .Neptunium would precipitate in the form of NpO2 and the solubility would be lower in reducing environment .The precipitation would change to be NaNpO2CO3 or NpO2OH in oxida‐tion environment and the solubility would be higher .The influence of pH on solubility depends on the speciation of precipitation .For NpO2 and NpO2 OH ,the solubility would＆amp;nbsp;increase with the total carbonate concentration at pH = 7.25 . For NaNpO2 CO3 , the solubility of neptunium would decrease with the increase of the total carbonate concen‐tration at pH=7.25 .
出处
《原子能科学技术》
EI
CAS
CSCD
北大核心
2015年第6期1005-1011,共7页
Atomic Energy Science and Technology
基金
国家自然科学青年基金资助项目(11305061)
国家科技重大专项资助项目(2011ZX06004-008)
高放废物地质处置专项基金资助项目(2012-851)
关键词
镎
溶解度
北山
地下水
CHEMSPEC
neptunium
solubility
CHEMSPEC
Beishan
groundwater
