This paper describes a methodology to identify partial defects in modelled spent nuclear fuel using passive gamma spectroscopy data. A fuel library, developed with Serpent2, was used to calculate the material composition of spent nuclear fuel. Two fuel configurations were investigated in this work; one where the fuel assembly configuration was intact and one where 30% of the fuelrods were substituted with stainless steel rods in a random configuration. Emission and detection of gamma radiation from 134Cs, 137Cs and 154Eu was simulated using a model of a passive gamma spectroscopy measurement station mimicking the Clab measurement station in Sweden. A simple HPGe detector model was implemented, and its detector efficiency was assessed using a range of different source energies. Realistic total gamma attenuation coefficients were calculated using the XCOM database.The modelled estimates of detected full-energy peak counts were then used in a Principal Component Analysis in order to investigate whether it was possible to distinguish between intact and partial defect fuel assemblies or not. The results showed that partial defects could be identified using the simultaneous analysis of all three peak intensities, and that the ability to do so increased when only gamma emission energies from 154Eu were considered.