Re-categorisation of High-Enriched Uranium and Plutonium for Safeguards Verification: Is It Necessary? What are the Other Options?

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.