Our research in nuclear forensics is performed in collaboration with Prof. Sunil Chirayath in the Department of Nuclear Engineering. The forensics collaboration is focused on developing techniques to discriminate the reactor origin and irradiation history of chemically separated Pu. Ideally, these forensic techniques may be applied in the investigation of trafficked or proliferated special nuclear material (SNM) to help determine their origin.
The major project in the collaboration is the development of a maximum likelihood methodology which compares a suit of simulated fission product (FP) isotope ratios (modeled under a variety of irradiation conditions) to a set of measured FP isotope ratios in actual samples containing Pu. The application of this forensic methodology requires the modeling and simulation of nuclear reactors using a Monte Carlo radiation transport code (MCNP6), as well as various radiochemical dissolutions, separations, and assays by radiation detection and mass spectrometry.
Chemists working on this project would likely find themselves handling high activities of radioactive FPs and actinides; hands-on work is performed with irradiated UO2 as well as Pu. Analytical separations including liquid-liquid extractions and multiple forms of chromatography are performed frequently. ICP-MS and gamma spectrometry are typically favored as analytical tools to assay metal content on the order of 0.01-1 ppb. Other analytical tools that will be used in future projects in the forensics collaboration include SEM, XRD, optical microscopy, and Raman spectroscopy.