Commissariat à l'Energie Atomique et aux énergies alternatives (CEA, DAM, DIF), F-91297, Arpajon, France; Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/ CNRS/UVSQ), Université Paris-Saclay, Gif-sur-Yvette, France.
Commissariat à l'Energie Atomique et aux énergies alternatives (CEA, DAM, DIF), F-91297, Arpajon, France.
Talanta. 2023 Jan 15;252:123848. doi: 10.1016/j.talanta.2022.123848. Epub 2022 Aug 18.
Every accident affecting industrial or nuclear facilities emits micrometric fragments of material into the environment whose elemental and isotopic compositions are characteristic of the process or event. Particle analysis, mainly implemented in the framework of the Non Proliferation Treaty to detect clandestine nuclear activities, provides a powerful tool to identify the origin of the nuclear particulate matter and to assess the environmental impact of nuclear accidents. Initially, particle-scale isotopic analyses aimed at the determination of the U isotopic composition. Now, focus is increasingly given on Pu isotopic measurements to address its origin and potential use. Such measurements are more challenging because of isobaric interferences, including those induced by hydride ions, like PuH on Pu and UH on Pu in Mixed Oxide (MOX). Such ions are generated during ionization processes by Secondary Ion Mass Spectrometry. Based on a parametric study aiming at the measurement of uranium oxide, uranium carbide and uranium single and double hydride rates, we determined that Pu and U should be detected as elementary ions to limit the impact of such interferences, although mono-oxide ions are more abundant. Thus, we developed an analytical methodology to obtain accurate Pu/Pu atomic ratios both for weapon grade Pu and MOX materials. Hydride rate is first measured in U oxide particles and then applied to correct Pu and Pu signals. The relative difference of corrected Pu/Pu isotopic ratios with expected values is reduced by a factor of 4 when measuring weapon grade Pu particles and by a factor of 10-100 when measuring MOX particles containing 1 to 10 wt% of Pu. We also proposed a method to determine the Relative Sensitivity Factor (RSF) based on the decay of Pu in order to quantify the Pu content in MOX samples. The estimated lowest measurable Pu/U atomic ratio in MOX particles is ∼1.6 × 10.
每一次影响工业或核设施的事故都会向环境中释放出微米级的物质碎片，其元素和同位素组成是该过程或事件的特征。颗粒分析主要是在不扩散条约的框架内实施，以检测秘密核活动，它为识别核颗粒物质的来源和评估核事故的环境影响提供了一个强大的工具。最初，颗粒尺度的同位素分析旨在确定 U 的同位素组成。现在，越来越关注 Pu 同位素测量，以确定其来源和潜在用途。由于同位干扰，包括由氢化物离子引起的干扰，如 Pu 上的 PuH 和 MOX 上的 UH，这种测量更具挑战性。这些离子是在二次离子质谱分析的电离过程中产生的。基于一项针对氧化铀、碳化铀和铀单氢化物和双氢化物速率测量的参数研究，我们确定应该以基本离子的形式检测 Pu 和 U，以限制这种干扰的影响，尽管单氧化物离子更丰富。因此，我们开发了一种分析方法，以获得武器级 Pu 和 MOX 材料的准确 Pu/Pu 原子比。首先测量 U 氧化物颗粒中的氢化物速率，然后应用于校正 Pu 和 Pu 信号。当测量武器级 Pu 颗粒时，校正后的 Pu/Pu 同位素比值与预期值的相对差异降低了 4 倍，当测量含有 1 至 10 wt% Pu 的 MOX 颗粒时，降低了 10-100 倍。我们还提出了一种基于 Pu 衰减的相对灵敏度因子（RSF）确定方法，以定量 MOX 样品中的 Pu 含量。在 MOX 颗粒中估计的最低可测量 Pu/U 原子比约为 1.6×10。
