Spectroscopic monitoring of spent nuclear fuel reprocessing streams: an evaluation of spent fuel solutionsviaRaman, visible, and near-infrared spectroscopy

Journal Article
Radiochimica Acta, vol. 99, iss. 9, pp. 563-572, 2011
Authors
S. A. Bryan, Tatiana G. Levitskaia, A. M. Johnsen, C. R. Orton, J. M. Peterson
Abstract
AbstractThe potential of using optical spectroscopic techniques, such as Raman and visible/near infrared (Vis/NIR), for on-line process control and special nuclear materials accountability applications at a spent nuclear fuel reprocessing facility was evaluated. The availability of on-line, real-time techniques that directly measure process concentrations of nuclear materials will enhance the performance and proliferation resistance of the solvent extraction processes. Further, on-line monitoring of radiochemical streams will also improve reprocessing plant operation and safety. This paper reviews the current state of development of the spectroscopic on-line monitoring techniques for such solutions. To further examine the applicability of optical spectroscopy for this application, segments of a spent nuclear fuel, with approximate burn-up values of 70 MW d/kg M, were dissolved in concentrated nitric acid and adjusted to varying final concentrations of HNO3. The resulting spent fuel solutions were batch-contacted with tributyl phosphate/n-dodecane organic solvent. The feed and equilibrium aqueous and loaded organic solutions were subjected to optical measurements. The obtained spectra showed the presence of quantifiable Raman bands due to NO3and UO22+and Vis/NIR bands due to multiple species of Pu(IV), Pu(VI), Np(V), the Np(V)-U(VI) cation–cation complex, and Nd(III) in fuel solutions. This result justifies spectroscopic techniques as a promising methodology for monitoring spent fuel processing solutions in real-time. The fuel solution was quantitatively evaluated based on spectroscopic measurements and was compared to inductively coupled plasma-mass spectroscopy analysis and Oak Ridge Isotope Generator (ORIGEN)-based estimates.
English