Security of Export Deliveries of Regenerated-Uranium Light-Water Reactor Fuel from the Standpoint of IAEA Safeguards

The nonproliferation of nuclear materials is the key issue in supplying nuclear fuel to foreign countries. This article discusses the use of regenerated uranium to enhance the security of exports of fresh fuel for light-water reactors. It is shown that if the removal of fuel and its replacement with, for example, natural uranium go undetected, the criminals have long periods of time available to obtain a significant amount of highly enriched uranium, having only several tens of separation devices. The nonproliferation regime can be strengthened by using regenerated uranium, which contains in its decay chain Tl-208 (2.61 MeV gamma-line) and is advantageously distinguished from U-235 (186 keV gamma-line). It is shown theoretically that by controlling the thallium content the uranium content in the fuel rods can be quickly analyzed before a fuel assembly is loaded into the core.