Isotopic and Compositional Variations in Single Nuclear Fuel Pellet Particles Analyzed by Nanoscale Secondary Ion Mass Spectrometry.
Isotopic and Compositional Variations in Single Nuclear Fuel Pellet Particles Analyzed by Nanoscale Secondary Ion Mass Spectrometry.
复制标题
通过纳米级二次离子质谱分析单个核燃料芯块颗粒的同位素和成分变化。
DOI：
10.1021/acsomega.9b02703
复制
发表时间：
2020
期刊：
影响因子：
4.1
通讯作者：
Fallon CM
中科院分区：
文献类型：
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作者：
Fallon CM
合作材料演习（CMX）由核法证国际技术工作组组织，旨在提高参与组织的分析能力，并就核法证调查的最佳方法提供反馈。在这里，使用NanoSIMS 50 L（CAMECA）分析了来自第5次CMX迭代的模型核燃料材料，以检查单个微米级颗粒内235 U/238 U比率和微量元素丰度的不均匀性。两个燃料芯块被制造用于演习，并标记为CMX-5A和CMX-5 B。这些芯块是使用不同的加工技术制造的，但都具有235 U/238 U = 0.01的目标富集值。从这些小球中分离出颗粒进行同位素和微量元素分析。分析了15个CMX-5A颗粒和20个CMX-5 B颗粒，两种样品类型在单个颗粒内的亚微米尺度下显示U同位素组成的不均匀性。CMX-5A的典型粒径为1.5至41 μm，CMX-5 B的典型粒径为1.1至61 μm。CMX-5A粒子显示出更均匀的同位素，平均235 U/238 U原子比为0.0130 ± 0.0066。CMX-5 B颗粒的平均235 U/238 U原子比为0.0063 ± 0.0094，这与芯块的目标浓缩值有很大差异，并突出了微米尺度下铀燃料芯块中235 U/238 U的潜在变化。这项研究详细介绍了NanoSIMS 50 L在模拟核法医调查中的成功应用，通过优化铀同位素的高分辨率成像。
The Collaborative Materials Exercise (CMX) is organized by the Nuclear Forensics International Technical Working Group, with the aim of advancing the analytical capabilities of the participating organizations and providing feedback on the best approaches to a nuclear forensic investigation. Here, model nuclear fuel materials from the 5thCMX iteration were analyzed using a NanoSIMS 50L (CAMECA) in order to examine inhomogeneities in the235U/238U ratio and trace element abundance within individual, micrometer scale particles. Two fuel pellets were manufactured for the exercise and labelled CMX-5A and CMX-5B. These pellets were created using different processing techniques, but both had a target enrichment value of235U/238U = 0.01. Particles from these pellets were isolated for isotopic and trace element analysis. Fifteen CMX-5A particles and 20 CMX-5B particles were analyzed, with both sample types displaying inhomogeneities in the U isotopic composition at a sub-micrometer scale within individual particles. Typical particle diameters were ∼1.5 to 41 μm for CMX-5A and ∼1 to 61 μm for CMX-5B. The CMX-5A particles were shown to be more isotopically homogeneous, with a mean235U/238U atom ratio of 0.0130 ± 0.0066. The CMX-5B particles showed a predominantly depleted mean235U/238U atom ratio of 0.0063 ± 0.0094, which is significantly different to the target enrichment value of the pellet and highlights the potential variation of235U/238U in U fuel pellets at the micrometer scale. This study details the successful application of the NanoSIMS 50L in a mock nuclear forensic investigation by optimizing high-resolution imaging for uranium isotopics.