Assessment of the impact of diversification of uranium switching on the risk of its non-energy use

The main objective of the IAEA verification activities is the timely detection of the switching of a significant quantity of nuclear material (NM). However, from the point of nuclear security the multiple switching of "small" quantities of nuclear material with the aim of their subsequent collection also constitutes one of the main threat to ensuring the exceptionally peaceful use of nuclear materials. In this article this threat assessments were performed under the scenario of diversification of uranium switching. It is shown that diversification of 4%-uranium switching can lead to a substantial increase (up to 30 times) of the risk of uranium disuse even with carrying out proper uranium control and protection. However this effect is observed only when there are large opportunities to search for insiders (the search area is comparable to the existing set of nuclear facilities). The obtained results also prove that a reduction in the level of NM safe management at facilities could allow the collector to complete a chain of unauthorized actions with a significant probability (PSQ>0.1).