Features of light-water reactor fuel made of reprocessed uranium in terms of IAEA safeguards implementation

One of the main priorities of nuclear power development is Non-Proliferation of Nuclear Weapons. So, the possibility of nuclear materials illicit diversion must be ruled out. This study aims to assess the chance of producing significant quantity of Highly enriched uranium (HEU) in case of covert diversion of fresh fuel. Analysis is carried out on the assumption that stolen reactor-grade Low enriched uranium (LEU) fuel was made of reprocessed uranium and got to be enriched to 90% ²³⁵U in gas centrifuges. As its isotopic composition contains a set of even-numbered minors ^232,234,236U, such operation for producing the main component of nuclear explosive device is harder comparing to one when fuel was made of natural uranium. Despite the higher proliferation resistance of reused fuel, there is a chance that it could be used in undeclared nuclear weapons programs. So, we are highlighting the importance of timely detection of nuclear materials diversion, especially for the LEU, which is the most sensitive to proliferation. Fortunately, due to unique physical properties of reprocessed uranium, such detection is possible with a quick NDA test even in case of a single fuel rod replacement. (paper)