TBP-TEVA萃取色层分离-α能谱法测定辐照镎靶溶解液中痕量^(236)Pu的可行性  

The Feasibility of Determining Trace ^(236)Pu in the Solution of Neptunium Target by TBP-TEVA Column Extraction Separation-Alpha Spectrum

作　　者：赵胜洋[1] 常志远[1] 应浙聪[1] 苏玉兰[1] ZHAO Shengyang;CHANG Zhiyuan;YING Zhecong;SU Yulan(China Institute of Atomic Energy, Beijing 102413, China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《同位素》2019年第1期37-44,I0002,共9页Journal of Isotopes

摘　　要：^(236)Pu的含量控制是钚热源的一项重要参数,通过α能谱准确测量镎靶溶解液中痕量^(236)Pu,建立镎靶辐照靶件溶解液中钚的分离方法。根据杂质组成特点采用TBP-TEVA萃取色层双柱分离,用氨基磺酸亚铁以及亚硝酸钠对钚进行调价,对靶件溶解液中的Al、Fe、U、Th和Np等进行分离,去污系数均大于104,钚的回收率为90.7%。研究大量^(238)Pu对α能谱测定^(236)Pu的干扰,结果表明,大量^(238)Pu会造成仪器本底升高,^(238)Pu能谱峰分辨率降低;在7 500Bq ^(238)Pu干扰下,测量4.3h时,^(236)Pu的最小可检测活度为1.20×10-2 Bq(当量质量为6.11×10-16 g)。计算结果表明,镎靶溶解液样品中钚的同位素比值n(^(236)Pu)/n(^(238)Pu)≥4.63×10-8时,取合适的样品量使得电沉积源中^(238)Pu活度在450～7 500Bq范围内,均可测量其中的痕量^(236)Pu,同时可准确测定同位素比值n(^(236)Pu)/n(^(238)Pu)。The content of 236 Pu in the 238 Pu product is limited in the range of 2 ppm to protect the workers during the manufacture of the heat source. Therefore, the content must be reduced as much as possible in the production process, and the 236 Pu content index must be strictly controlled. The control of plutonium content is an important parameter of plutonium heat source, studied the conditions for accurate measurement of trace 236 Pu in irradiated Np target. A separation method for Pu in the solution of irradiated Np target was established. According to the composition of solution, TBP-TEVA double extraction chromatographic column separation was adopted. The plutonium valence was adjusted by FS sulfonic acid and sodium nitrite, and the impurities of Al, Fe, U, Th and Np in the plutonium were decontaminated, the decontamination coefficient was greater than 10^4, and the recovery of plutonium was 90.7%. In this paper, the interference of a large amount of 238 Pu on 236 Pu was studied, and the results showed that a large amount of 238 Pu would cause increasing of the background, and coarsening of the resolution of 238 Pu peak and increase the MDA. The MDA of 236 Pu is 1.20× 10 ^-2 Bq and the isotope ratios of n ( 236 Pu / 238 Pu ) is 4.63×10 ^-8 , when the 238 Pu is 7 500 Bq background interference and measure it for 4.3 h. When the isotope ratios of n ( 236 Pu / 238 Pu ) is more than or equal 4.63×10 ^-8 in the sample of irradiation Np target, meanwhile sampling the suitable amount can make the 238 Pu activity in the electroplating source range from 450-7 500 Bq, then the trace 236 Pu can be detected, and the ratios of n ( 236 Pu / 238 Pu ) can be accurately measured. The determination of trace 236 Pu in 238 Pu heat resource is an important technical indicator in neptunium target irradiation process and product of heat source. In this study, the combined TBP-TEVA resin was used to separate and purify the plutonium from the irradiated neptunium target solution, and the alpha energy spectrum method was used to analy

关 键 词：钚同位素 镎靶 α能谱 痕量分析 

分 类 号：TL12[核科学技术—核能科学] O657.62[理学—分析化学]