摘要/Abstract

铀-236是一种重要的人工放射性核素, 是三种天然铀同位素之外可以应用在环境示踪、核应急、核取证以及核保障中的一种铀同位素. 人工²³⁶U主要是由核燃料²³⁵U经过中子照射后吸收中子产生, 因此, 不同“年龄”阶段核燃料中的²³⁶U和其他同位素的比值(指纹特征)截然不同. 同时不同反应堆类型中相应指纹特征也不尽相同. 通过监测核燃料、可疑核材料以及环境样品中不同²³⁶U/²³⁸U、²³⁶U/²³⁵U同位素比值等指纹特征即可确认反应堆运行状况、追溯核材料来源出处, 甚至可以开展放射性核污染物在环境中的迁移模拟等问题. 铀-236属于低丰度同位素, 其在核样品和环境样品中含量极低, 因此, 精确测定其同位素比值对²³⁶U在环境示踪、核应急、核取证以及核保障中的应用尤为重要. 本综述中, 作者总结了近年来痕量²³⁶U测定时样品前处理和检测分析技术的发展, 尤其着重于²³⁶U同位素比值的质谱检测技术的发展, 以及²³⁶U在核保障和环境中的示踪应用的研究进展. 最后, 对痕量²³⁶U检测和应用方面的研究提出展望.
关键词: ²³⁶U, 质谱分析, 前处理方法, 示踪应用, 核保障
Uranium-236 is an important anthropogenic radionuclide except for the three main natural uranium isotopes, which could be applied in the fields of environmental tracer, nuclear emergency response, nuclear forensics and nuclear safeguards. Artificial ²³⁶U is mainly generated through neuron absorption of nuclear fuel ²³⁵U after neuron irradiation. Therefore, the isotopic ratios of ²³⁶U with other uranium isotopes (fingerprints) are different at different nuclear fuel age. Also, the corresponding fingerprints are different in different types of nuclear reactor. The operation statue of nuclear reactor, the source of nuclear material and the migration of released radionuclides in environment could be studied by analyzing the isotopic ratios of ²³⁶U/²³⁸U and ²³⁶U/²³⁵U in the corresponding samples. Since ²³⁶U is a minor isotope and its concentration is extremely low in nuclear material and environmental samples, it is important to accurately analyze the isotopic ratios for its application in the environmental tracer, nuclear emergency response, nuclear forensics and nuclear safeguards. In this review, we summarized the development of sample pretreatment and analysis technologies for ²³⁶U measurement in recent years, especially focused on the development of ²³⁶U isotopic ratio analysis using mass spectrometry, and the research progress of ²³⁶U application in the fields of nuclear safeguards and environmental tracer was also reviewed. The research prospect for ²³⁶U analysis and application was also proposed.
Key words: ²³⁶U, mass spectrometry, pretreatment technique, tracer application, nuclear safeguards


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