摘要
N,N,N’,N’-四辛基-3-氧戊二酰胺(N,N,N’,N’-tetraoctyl-diglycolamide,TODGA)是一种具有广泛发展前景的针对锕系核素萃取分离的酰胺荚醚类萃取剂。为研究TODGA在煤油介质中的γ辐照性能,研究采用超高效液相色谱手段,以煤油作稀释剂,研究了水相中不同硝酸浓度下γ吸收剂量对TODGA辐解的影响;评价了辐照后TODGA-煤油-3 mol·L^(-1)硝酸混合体系对碱土金属、镧系元素的萃取性能变化。研究表明:TODGA的辐解率随着体系中硝酸浓度的升高而逐渐下降,当水相添加4 mol·L^(-1)硝酸水溶液,相较于不含硝酸水溶液时可抑制18%程度的辐解。而吸收剂量的增加导致了TODGA辐解增加,当吸收剂量低于100 kGy时,TODGA的辐解程度为10%~40%;当吸收剂量为1000 kGy时,TODGA的辐解增加明显,辐解率高达70%。TODGA辐解主要由醚键断裂导致,在硝酸水溶液的作用下改变辐解路径,还会发生辛基侧链的断裂。TODGA对碱土金属元素Sr的初始萃取率为25%,吸收剂量为100 kGy时几乎不萃取Sr,而其对镧系元素(Ce、Eu、Dy)的萃取率接近100%。
[Background]With the development of nuclear energy,spent nuclear fuel reprocessing has generated high-level liquid waste(HLLW)containing large quantities of minor actinides(e.g.,Np,Am,and Cm).N,N,N',N'-tetraoctyl-diglycolamide(TODGA),an amide ether extraction agent,has immense potential for the extraction and separation of actinides from HLLW.However,HLLW is characterized by high radioactivity,which can destroy the molecular structure of TODGA and diminish its extraction capacity.In addition,the type of organic medium selected to dilute TODGA has a significant impact on its extraction ability and radiolysis.[Purpose]This study aims to evaluate the gamma radiolysis and extraction performance of TODGA in a kerosene medium.[Methods]Firstly,several experimental reagent systems were prepared.Organic phase:50 mmol∙L^(−1) TODGA/kerosene;aqueous phase:0~4 mmol∙L^(−1) HNO_(3);absorbed doses:5~1000 kGy by a 60Co gamma-irradiator(3.7×10^(15 )Bq)at room temperature;absorbed dose rates:0.6 kGy∙h^(−1)(5~15 kGy)and 5.8 kGy∙h^(−1)(50~1000 kGy).Then,ultra-performance liquid chromatography(UPLC)and mass spectrometer were used to identify the components in the organic phase and assess the relative concentrations of TODGA and radiolysis products before and after irradiation.Lanthanides(substitutes for actinides)and alkaline earth metals were extracted using TODGA at different absorbed doses(5~100 kGy)and the concentration of metal ions for extraction was 100μg∙mL^(-1) in 3 mmol∙L^(−1) HNO_(3).Finally,after extraction and dilution,the aqueous phase was detected using an inductively coupled plasma-optical emission spectrometer to estimate the lanthanide and alkaline earth metal concentrations.[Results]The experimental results indicate that the concentration of TODGA steadily increases with increasing concentrations of HNO_(3) at a radiation dose of 1000 kGy.The radiolysis rate of TODGA in the acid-free solution is>80%.Compared to the acid-free solution,the degree of radiolysis can be inhibited at approximately
作者
农淑英
郑嘉威
杨舒夷
杨安波
吴艳
NONG Shuying;ZHENG Jiawei;YANG Shuyi;YANG Anbo;WU Yan(The 404 Company Limited,China National Nuclear Corporation,Jiayuguan 735112,China;School of Nuclear Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《核技术》
EI
CAS
CSCD
北大核心
2024年第6期45-55,共11页
Nuclear Techniques
关键词
TODGA
超高效液相色谱
Γ辐照
辐射分解
萃取
TODGA
Ultra-performance liquid chromatography(UPLC)
Gamma irradiation
Radiolysis
Extraction
