Automated Burnup Analysis from Metallic, Ceramic, and Amorphous Fuels using Atom Probe Tomography

The burnup measurement in nuclear fuels is critical for evaluating fuel performance and ensuring safe transfer and storage of spent fuel. Accurate calculation of burnup requires tracking the consumption of fissile isotopes such as uranium (U) and plutonium (Pu), offering a direct insight into energy changes within the fuel. Atom Probe Tomography (APT) stands out as an exceptional technique, capable of providing precise chemistry and isotopic analysis at a high resolution and sensitivity on a small length scale (nanometers). Despite its advantages, quantifying isotopes poses challenges due to the asymmetric shapes of mass spectrum peaks and delayed signals, known as thermal tails, particularly for poorly conducting samples, leading to peak overlaps. In this study, we introduce a novel quantification tool for isotope analysis from APT datasets in the context of nuclear fuels. We have developed a Matlab-based dynamic peak fitting algorithm designed to adapt to various peak shapes, ensuring accurate quantification of U isotopes. The results from this quantification tool are then employed for burnup estimation. The effectiveness of this approach is demonstrated in standard samples, as well as enriched samples and those with different burnup levels, involving both U-based metallic, ceramic and amorphous fuels.