Characterizing the Morphology and Chemistry of Oxides Formed on Plutonium Metal Alloys

Nuclear forensics requires accurate identification of distinguishing material characteristics to determine the origin and pathways of interdicted nuclear materials. The internal morphology and chemistry of the oxide formed on two plutonium (Pu) metal alloys was characterized following exposure to various environments that could be anticipated under a loss-of-institutional-control scenarios. Using a combination of focused ion beam (FIB) and Auger electron spectroscopy (AES), distinguishing morphological and chemical characteristics between the oxide scale formed from during controlled storage and the oxide subsequently formed during exposure to external environments were determined. Variation in the internal chemical composition, structure, and pore geometry of the oxide were found to occur between alloy composition and humidity of the repackaging environment. This information is of potential use in predicting and discriminating material characteristics related to the history and recent provenance of interdicted nuclear materials.<br/> <br/>This work was prepared by LLNL under Contract DE-AC52-07NA27344 and was supported by the Office of Defense Nuclear Nonproliferation Research and Development within the U.S. Department of Energy’s National Nuclear Security Administration. This support does not constitute an express or implied endorsement on the part of the government.