Transparency Methods Development using Fission Product Signatures

Abstract:

A method for unique identification of spent nuclear fuel has been developed in order to enhance transparency in international safeguards. Demand for nuclear power is experiencing a worldwide surge. This surge requires enhanced transparency methods for use by the IAEA and those responsible for safeguarding the world’s nuclear material. Previous methods existed to identify spent fuel burnup, reactor type, initial enrichment, and other parameters. However, despite knowledge of such parameters it was not possible to distinguish spent fuel of the same burnup, reactor type, enrichment, etc. The power history experienced by reactor fuel is dependent on core power level and the position of the fuel within the core. Thus a technique to determine the power history of the fuel can serve as a unique identification method for spent nuclear fuel. Research has been completed to identify fission product isotopes capable of serving as power history monitors. These monitor isotopes have concentrations sensitive to variations in power history even while final burnup was held constant. Through this work an understanding of the physical mechanisms responsible for such concentration differences has been developed. It was seen for simple power history variations simulated with TransLat lattice physics code that identified fission product signatures varied up to 280 % with signatures from the base case power history. This method could be applied at reprocessing facilities to ensure that spent fuel has not been diverted or substituted with other spent fuel.

Example Monitor Behavior for Te-127m (radioactive)