PC FRAM and InterSpec software comparison for uranium isotopic composition determination

For nuclear forensics, safety, and non-proliferation verification, an accurate assessment of uranium isotopic composition in materials that are under or outside of regulatory control is essential. In this work, two software - PC FRAM and InterSpec are tested for isotopic analysis of uranium enrichments in gamma spectra. Los Alamos National Laboratory created the well-known, proprietary PC FRAM software specifically designed for plutonium and uranium isotopic determination, while InterSpec is an open-source alternative usually used for the general analysis of gamma spectra. In order to test the usability and accuracy of InterSpec software for uranium isotopic determination, the comparative analysis of PC FRAM and InterSpec results were performed on gamma spectra of reference materials of various enrichments as well on other DU and HEU spectra with unknown enrichment. The findings show that, when properly configured, InterSpec can produce trustworthy preliminary estimates, but FRAM consistently yields higher precision and lower bias in enrichment determination. In order to increase InterSpec's utilization potential as an affordable substitute in international nuclear measurement applications, additional development and parameter optimization is necessary. The obtained results suggest that InterSpec has potential as an initial screening and enrichment estimation tool, but it cannot replace PC FRAM for more precise isotopic determinations.