Precise U and Pu Isotope Ratio Measurements in Nuclear Samples by Hyphenating Capillary Electrophoresis and MC-ICPMS

Abstract

Precise isotopic and elemental characterization of spent nuclear fuel is a major concern for the validation of the neutronic calculation codes and waste management strategy in the nuclear industry. Generally, the elements of interest, particularly U and Pu which are the two major elements present in spent fuel, are purified by ion exchange or extractant resins before off-line measurements by thermal ionization mass spectrometry. The aim of the present work was to develop a new analytical approach based on capillary electrophoresis (CE) hyphenated to a multicollector inductively coupled plasma mass spectrometer (MC-ICPMS) for online isotope ratio measurements. An electrophoretic separation protocol of U, Pu, and the fraction containing fission products and minor actinides (Am and Cm) was developed using acetic acid as the electrolyte and complexing agent. The instrumentation for CE was designed to be used in a glovebox, and a laboratory-built interface was developed for hyphenation with MC-ICPMS. The separation was realized with only a few nL of a solution of spent nuclear fuel, and the reproducibilities obtained on the U and Pu isotope ratios were on the order of a few ‰ which is comparable to those obtained by thermal ionization mass spectrometry (TIMS). This innovative protocol allowed a tremendous reduction of the analyte masses from μg to ng and also a drastic reduction of the liquid waste production from mL to μL. In addition, the time of analysis was shorted by at least a factor of three. All of these improved parameters are of major interest for nuclear applications.

Method development for on-line species-specific sulfur isotopic analysis by means of capillary electrophoresis/multicollector ICP-mass spectrometry

“…For the introduction of the bracketing standard measured in a sample-standard bracketing sequence, a setup similar to that reported by Martelat et al [ 30 ] using a second nebulizer for standard introduction was considered. However, the addition of the standard aerosol resulted in wet plasma conditions decreasing the width of the 32 S plateau region because of a significant increase of the intensity of the interfering 16 O 2 + signal.…”

“…However, despite its potential, up to now, CE/MC-ICP-MS has only been used for on-line species-specific isotopic analysis by one group. Martelat et al developed an approach for isotopic analysis of uranium and plutonium with a spray chamber accommodating two nebulizers, one for introducing the CE flow and the other for the bracketing standard, which was introduced during time segments without electrophoretic peaks [ 30 ]. Given the interference issues for sulfur arising from the introduction of liquids, the potential of the approach for isotopic analysis of this element must be thoroughly evaluated.…”

Integration of High-Resolution Radiation Detector for Hybrid Microchip Electrophoresis

“…17,18 CE has also been used for separation of radioactive compounds in applications such as assessing the purity of radiopharmaceuticals labeled with positron-emitting isotopes for positron-emission tomography (PET) or with gamma-emitting isotopes for single photon emission computed tomography (SPECT), 19,20 as well as the analysis of radioisotopes in nuclear fuel development. 21,22 Due to the small sample volumes used in CE, detectors and flow cells must be designed to maximize detection efficiency, especially for radiation detection. Several radiation detection approaches have been reported in the literature for CE applications.…”

“…Capillary electrophoresis (CE) has been used in a wide variety of fields such as separation of biomolecules, − environmental monitoring, , food analysis, , and forensics . Typically, compounds are detected via UV absorbance, though many additional modes of detection can be implemented, including pulsed amperometric detection, capacitively coupled contactless conductivity detection, − refractive index detection, mass spectrometry, , and fluorescence. , CE has also been used for separation of radioactive compounds in applications such as assessing the purity of radiopharmaceuticals labeled with positron-emitting isotopes for positron-emission tomography (PET) or with gamma-emitting isotopes for single photon emission computed tomography (SPECT), , as well as the analysis of radioisotopes in nuclear fuel development. , …”

Progress and Application on the Analysis of Anthropogenic Radionuclide236U

“…天然 236 U 在海洋中 含量约 0.5 kg, 而 238 U 在海洋中浓度约为 3 ng/mL [14] [12] [4,[15][16] 以及钚同位素 [17][18][19] 、 237 Np [20][21] 、 241 Am [22][23] 等超铀核素 均有较多的文献报道, 尤其是其在核保障中的应用 [24] . 关于铀同位素质谱方法, 电感耦合等离子体串联质谱 (ICP-MS/MS) [25] 、 多 接 收 电 感 耦 合 等 离 子 体 质 谱 (MC-ICP-MS) [15,26] 、热电离质谱(TIMS) [27][28] 、二次离子 质谱(SIMS) [29] 、加速器质谱(AMS) [30] 、激光剥蚀电感耦 合等离子体质谱(LA-ICP-MS) [31] 均可以实现铀同位素的 检测分析. 相比 α 谱仪分析方法, 质谱技术可以实现样 品的快速检测分析, 加之质谱检测限较低, 可以达到 pg 级, 甚至是 fg 级, 因此, 通过质谱技术可以实现环境样 品、核相关擦拭样品及其他可疑核材料样品中超痕量铀 同 位 素 及 其 比 值 的 检 测 分 析 .…”