Abstract The desirability and necessity of having a relook into the re-categorization of International Atomic Energy Agency (IAEA) defined High-Enriched Uranium (HEU) and Plutonium (Pu) by focussing on the relevance of strategic value/isotopic composition of the materials for re-categorization, for example, creating an intermediate category between the existing Low Enriched Uranium (LEU) and weapons-grade uranium (U-235 > 90 per cent) and re-categorizing plutonium into Weapons-Grade Plutonium (WGPU) and Reactor-Grade Plutonium (RGPU), specifying the content of Pu-240 in each case, had been suggested by various specialists. According to them, this re-categorization facilitates flexible IAEA inspection goals, does not compromise on safeguards efficacy and at the same time could result in reduced inspection efforts and costs. An assessment has been made from the available literature and it is possible to conclude that (i) only a relatively small enrichment effort is needed to enrich uranium with 20 per cent U-235 to weapons-grade uranium and (ii) non-weapons-grade plutonium can also be used in nuclear weapons. This article therefore argues that there is no need to change the existing IAEA categorization of HEU and Pu, and the current IAEA practices should continue for a more meaningful safeguards implementation. In addition, it is argued that technological advancements in safeguards verification, and pragmatic adaptation of integrated safeguards, state-level approach may bring about flexibility in safeguards approach. Further, it is suggested that with a large safeguards verification database at its disposal, the IAEA may take a decision on revising the value of Significant Quantity (SQ) without changing other criteria.

中文翻译：

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重新分类高浓缩铀和钚以进行保障核查：是否有必要？其他选项是什么？

摘要 重新审视国际原子能机构 (IAEA) 定义的高浓缩铀 (HEU) 和钚 (Pu) 的重新分类的可取性和必要性，重点是材料的战略价值/同位素组成的相关性。重新分类，例如，在现有的低浓缩铀 (LEU) 和武器级铀 (U-235 > 90%) 之间创建一个中间类别，并将钚重新分类为武器级钚 (WGPU) 和反应堆-各种专家都建议使用钚级 (RGPU)，具体说明每种情况下 Pu-240 的含量。据他们介绍，这种重新分类有助于实现灵活的原子能机构视察目标，不会损害保障效力，同时可能会减少视察工作和成本。根据现有文献进行了评估，可以得出以下结论：(i) 只需要相对较小的浓缩工作即可将 20% U-235 浓缩为武器级铀和 (ii) 非武器-钚也可用于核武器。因此，本文认为没有必要改变 IAEA 对 HEU 和 Pu 的现有分类，目前 IAEA 的做法应该继续进行，以实现更有意义的保障监督。此外，有人认为保障核查方面的技术进步、综合保障的务实适应、国家级方法可能会带来保障方法的灵活性。此外，建议利用一个大型保障核查数据库，