Microscopy and spectroscopy of plutonium dioxide aging under ambient and near-ambient conditions

Abstract Characterization of nuclear materials under controlled conditions promotes a better understanding of their chemistry and provides insight into their stability. Of particular importance is identifying how environmental and storage conditions affect both bulk and sub-bulk scale chemical and physical properties. Such data may provide insight for nuclear forensic applications and can help address fundamental safety and storage concerns. In this work, plutonium dioxide (PuO2) and thorium dioxide (ThO2) aging was studied as a function of temperature and relative humidity (RH) while simultaneously observing the effects of fluoropolymer containment. Morphological changes were monitored using scanning electron microscopy and interpreted utilizing a previously-published lexicon of descriptive imaging terminology. Changes in phase were observed using X-ray diffraction measured on a single-crystal X-ray diffractometer to permit sub-bulk scale (