Title  Investigation of Optical Spectroscopy Techniques for On-Line Materials Accountability in the Solvent Extraction Process	Researchers G. Cerefice Collaborators George Vandergrift, Argonne National Laboratory
Background  Increasing the proliferation resistance of the nuclear fuel cycle is one of the stated goals for the Global Nuclear Energy Partnership program.  From a proliferation aspect, the greatest challenge to closing the nuclear fuel cycle is ensuring that nuclear material is not diverted during the recycling processes.  As part of the safeguards-by-design concept, new separations facilities will incorporate integral systems capable of providing materials accountability for the actinide elements to minimize the potential for undetected diversion of material.  The goal of this project is to evaluate technologies to meet this need.  Optical spectroscopic techniques, such as Ultraviolet-Visible Spectroscopy (UV/Vis) and Laser Fluorescence Spectroscopy (LFS), are quantitative analytical techniques that have been used for measuring the concentration of the actinides under laboratory conditions.  In UV/Vis spectroscopy, the sample is illuminated by a continuous spectrum (from the UV through the Visible wavelengths).  The transmitted light is measured, allowing the determination of the absorbance of the light as a function of wavelength.  The wavelength of the absorbance is dependant on the electronic structure of the absorbing atom, and is proportional to the concentration of the absorbing element in the sample.  For LFS, the sample is illuminated at a single wavelength, which is absorbed by the target atoms in the sample.  The energy absorbed is re-emitted through fluorescence.  The wavelength of the absorbance, and the fluorescence-response, is again dependant on the electronic structure of the absorbing atom, and is proportional to the concentration of the absorbing element in the sample.    Both techniques are strongly dependent on the chemical speciation of the elements to be measured, providing a tool for not only the determination of material concentrations for mass balances, but also providing inspectors and plant operators with a tool to examine the process chemistry itself.  As optical techniques, both of these methods can be adapted for fiber optics, allowing the instrumentation to be placed in shielded areas of the plant to minimize the impact of the radiation fields on the detectors and increase the accessibility of the systems for maintenance and inspection.   Laser induced fluorescence of a uranium sample in nitric acid	Research Objectives and Methods The goal of this project is to evaluate the application of these analytical techniques to the on-line, real-time measurement of the actinide elements in the process streams of a solvent extraction process, with particular attention to the UREX+ and PUREX processes.  Based on the experience gained through this effort, engineers will have the information necessary to decide if these technologies should be advanced to the prototype stage and tested at the pilot plant level.  Through the experimental work planned as part of this effort, researchers will also develop a better understanding of the chemical interactions of the actinide elements, providing additional data for the development of first-principles based models of the solvent extraction process.  The information gathered through these experiments will also add to the database on the UREX+ solvent extraction process, particularly in the off-normal operating regimes.  The research objectives are: · To evaluate the potential for utilizing UV-Visible and laser fluorescence spectroscopy to determine actinide concentrations under process conditions, including the spectroscopic impact of acid concentration, solvent vs. aqueous product streams, ligand concentrations (TBP, AHA), and chromophoric agents (e.g. iron) from fission products or corrosion/degradation products. · To examine what process chemistry information can be extracted from the spectroscopic signals along with the actinide metal concentrations. · To examine the fundamental chemistry underlying the spectroscopic behavior under process conditions in support of process chemistry modeling activities.
Students  Nicholas Smith G   Jeremy Maute G	Department Mechanical Engineering
Final Report	Annual Report
Proposal 04/01/05	Quarterly Reports   01/01/06-03/31/06