| Description |
Nuclear forensics is a discipline that was ushered in with the development of nuclear weapons and energy in the last century. It entails the analysis of nuclear and radioactive materials to determine the origin and history of a material of interest. A major focus of current nuclear forensics research is the development of analytical techniques that can provide insight into the synthesis procedures and conditions experienced by a uranium oxide. Current techniques are often time-intensive and provide little information regarding the precipitation and calcination conditions used to generate a nuclear material. This study aims to develop novel quantitative signatures that will increase the confidence in correctly identifying the synthesis chemistries and conditions used to generate a uranium oxide, and consequently an originating facility. Uranium ore concentrates (UOCs) were synthesized using common precipitants and conditions encountered in the real world. Thermogravimetric analysis-mass spectrometry (TGA-MS) was used to provide quantitative signatures unique to the thermal decomposition of the UOCs through analysis of their temperature dependent mass losses and analysis of their volatile decomposition products. An additional signature, based on morphology, was also developed to yield quantitative information on the precipitation and calcination conditions experienced by the sample. Scanning electron microscopy (SEM) was utilized to acquire images of the surface morphology for uranium oxides, and the novel application of quantitative analysis of the size and shape of the microfeatures provided signatures indicative of the synthetic conditions for the material and its precursors. In addition to the general synthetic pathways, the impact of variable calcination temperature was determined to induce statistically significant differences in the morphology and microstructure for thermally decomposed uranyl peroxide (washed and unwashed). As a final signature, powder X-ray diffraction (p-XRD) was used to provide information on the crystalline content and structure of investigated materials. Frequently, uranium oxides are encountered with a significant and measurable x-ray amorphous component. This study presents the first instance that amorphous content quantification was utilized as a nuclear forensics signature. Ultimately, results from this study demonstrate the development of multiple novel nuclear forensics signatures from crystallography, morphology, and thermal decomposition. The results from this study led to the development of a new field of science termed nuclear proliferomics. |
