Quantifying Morphological Features of α-U₃O₈ with Image Analysis for Nuclear Forensics

Abstract

Morphological changes in UO based on calcination temperature have been quantified enabling a morphological feature to serve as a signature of processing history in nuclear forensics. Five separate calcination temperatures were used to synthesize α-UO, and each sample was characterized using powder X-ray diffraction (p-XRD) and scanning electron microscopy (SEM). The p-XRD spectra were used to evaluate the purity of the synthesized U-oxide; the morphological analysis for materials (MAMA) software was utilized to quantitatively characterize the particle shape and size as indicated by the SEM images. Analysis comparing the particle attributes, such as particle area at each of the temperatures, was completed using the Kolmogorov-Smirnov two sample test (K-S test). These results illustrate a distinct statistical difference between each calcination temperature. To provide a framework for forensic analysis of an unknown sample, the sample distributions at each temperature were compared to randomly selected distributions (100, 250, 500, and 750 particles) from each synthesized temperature to determine if they were statistically different. It was found that 750 particles were required to differentiate between all of the synthesized temperatures with a confidence interval of 99.0%. Results from this study provide the first quantitative morphological study of U-oxides, and reveals the potential strength of morphological particle analysis in nuclear forensics by providing a framework for a more rapid characterization of interdicted uranium oxide samples.

Quantifying Impurity Effects on the Surface Morphology of α-U3O8

“…Control samples were synthesized through the same procedure without the addition of impurities. The synthesis of studtite, (UO 2 )­O 2 (H 2 O) 2 ·2H 2 O, from UNH and a molar excess of H 2 O 2 was described previously . Six total replicates were synthesized, and replicates 1–3 were filtered and washed with three aliquots of 50 mL of Millipore water to remove any residual nitrates .…”

“…Morphological features of U oxides have been previously shown to be a result of processing parameters including dependence on the starting material, intermediate material, oxidation rates, precipitation conditions, and thermal history . These were the first studies to successfully quantify morphological analysis of nuclear material and were essential to advancements in nuclear forensics and the nuclear fuels community.…”

Progress in Uranium Chemistry: Driving Advances in Front-End Nuclear Fuel Cycle Forensics

“…In particular, recent research has examined the morphology of various uranium oxides, with a focus on discerning process history or process conditions for a particular sample of material. [20][21][22][23][24][25][26][27][28][29][30][31][32]46 One outcome of these efforts was a lexicon to standardize descriptions of material images for nuclear forensics, indicating a likely increasing role for morphology within nuclear forensics. 33 Recent research has also investigated elemental and chemical impurities present in process samples of uranium compounds, also with a focus of discerning process history as well as the origin of the uranium.…”

Overview of Algorithms for Using Particle Morphology in Pre-Detonation Nuclear Forensics

“…References [1][2][3][4][5][6][7] describe pre-detonation nuclear forensics goals. Pre-detonation nuclear forensics focuses on determining the source and route of nuclear materials and devices prior to their use in an improvised nuclear device or radiological dispersal device.…”