ABSTRACT Present safeguards verification methods for small samples of high-radioactivity nuclear material (e.g. spent nuclear fuel solution) in reprocessing facilities use destructive analysis techniques since passive non-destructive techniques are incapable of directly determining the nuclear material content. To supplement these methods, the Japan Atomic Energy Agency and European Commission Joint Research Centre (JRC) are collaborating to develop delayed gamma-ray spectroscopy non-destructive assay technology for composition analysis of the fission nuclides. Multiple experiments were performed in the JRC-Ispra site using the Pulsed Neutron Interrogation Test Assembly (PUNITA) to study the signature from short-lived fission products from low-radioactivity U and Pu standard samples. From these spectra, we identify many gamma rays useful to determine the composition of a mixed nuclear material sample. Here we present the results of these experiments along with correlations to the interrogation, mass, volume, and sample homogeneity.

中文翻译：

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利用 PUNITA 实验评估核保障的基本延迟伽马射线光谱询问要求

摘要 目前对后处理设施中高放射性核材料（例如乏核燃料溶液）小样本的保障核查方法使用破坏性分析技术，因为被动非破坏性技术无法直接确定核材料的含量。为了补充这些方法，日本原子能厅和欧盟委员会联合研究中心 (JRC) 正在合作开发用于裂变核素成分分析的延迟伽马射线光谱无损分析技术。在 JRC-Ispra 站点使用脉冲中子询问测试组件 (PUNITA) 进行了多项实验，以研究来自低放射性 U 和 Pu 标准样品的短寿命裂变产物的特征。从这些光谱中，我们确定了许多有助于确定混合核材料样本成分的伽马射线。在这里，我们展示了这些实验的结果以及与询问、质量、体积和样品均匀性的相关性。