The UK’s nuclear legacy includes a broad range of Spent Nuclear Fuels (SNF), stored across multiple sites. As part of ongoing decommissioning and waste management efforts, there is the potential for Sellafield to receive such SNF packages from external locations. For some of these packages, material knowledge is limited due to missing identifiers and incomplete historical records, compounded by restricted access for direct inspection in their current storage configuration. This uncertainty necessitates conservative assumptions—such as treating all material as containing significant quantities of fissile isotopes—which challenges an acceptable transport safety case being made.
This project adopts a computational approach using Monte Carlo N-Particle (MCNP) simulations to model the geometries of cans containing various fuel types, including (UO₂) and mixed oxide (MOX) fuels, and to generate gamma-ray spectra through photon transport and detection. The aim is to evaluate the feasibility of comparing and analysing these spectra to verify heavy metal content and identify fuel type, thereby reducing uncertainties associated with fuel package transport and supporting a justifiable safety case.
