Title: NDA Characterization of TRISO Burnup
Author: Stefania Dede1, Mark Croce1, Emily Stark1, Christine Mathew1, Daniel McNeel1, Katherine Schreiber1, Rico Schoenemann1, Matthew Carpenter1, Sophie Weidenbenner1, Callie Goetz2, Jason Harp2, Jianwei Hu2, Robert McElroy2, Craig Gray2, Ammon Williams3, Edward Seabury3, Brian Bucher3, Paige Abel3
1Los Alamos National Laboratory, Los Alamos, NM 87545, USA
2Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
3Idaho National Laboratory, Idaho Falls, ID 83415, USA
Abstract: Nondestructive analysis (NDA) is a crucial tool that enables cost-effective safeguards for advanced nuclear reactors by providing precise and reliable measurements of radioactive materials. This research focuses on understanding how NDA methods can be optimized for fissile material measurements in TRISO fuels used in pebble-bed reactors. By directly measuring NDA uncertainties, we aim to develop a comprehensive set of validated capabilities for safeguards models. Our current efforts are directed toward supporting on-line burnup measurement systems, determining whether individual fuel pebbles have reached target burnup, and assessing the fissile material content of irradiated fuel for safeguards purposes.
TRISO-based pebble fuel is particularly well-suited for NDA due to its physical properties, size, and shape, which make it an ideal sample for NDA analysis. The fuel’s characteristics enable the measurement of plutonium K X-ray lines using γ spectroscopy, facilitating precise correlations between measured plutonium (Pu) and uranium (U) X-ray peak ratios and burnup. Data from the AGR series demonstrate a strong correlation between these ratios and burnup, underscoring the potential of NDA techniques to provide critical insights for advanced fuel cycle safeguards and online monitoring systems.