The analysis of uranium-232. Comparison of radiochemical techniques and an improved method by alpha spectrometry

Uranium-232 is an isotope of interest for nuclear forensic studies because it can provide information on the irradiation history of a sample of uranium. The isotope is formed in uranium materials through several pathways and is typically found at ultra-trace levels (usually ng/g or smaller) in typical uranium materials. The low abundance of this isotope in irradiated materials makes it very difficult to measure accurately and precisely. Many different methods have been proposed for the analysis of 232U using radiochemical methods including alpha and gamma spectrometry. In this paper, literature methods will be discussed and an improved method using alpha spectrometry will be presented. Alpha spectrometry offers a direct analysis technique for measuring 232U, with few interferences that can be removed via separations. Results from our improved method will be presented and compared to results obtained from a non-destructive gamma spectrometry method that utilizes an indirect measurement. LA-UR-12-20186. (author)