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A new approach to x-ray absorbance analysis of actinides
Description:
By itself or in combination with fluorescence analysis, K- and L-edge x-ray absorbance analysis is an established technique for the measurement of actinide concentrations in nuclear materials. Still, there are common process analysis scenarios that challenge the method. Elements separated by 1 or 2 atomic numbers (U/Np, U/Pu) interfere with each other. L-edge bands for actinides also overlap with K-edge transitions from transition metals. Backgrounds will vary due to changes in the fission product content, non-resonant scattering of solution components, or the x-ray source output. Measurement of a matrix-matched reference spectrum, as is commonly practiced for offline measurements, is difficult and time-consuming in the on-/in-line environment. Here, we describe a novel approach to transforming transmitted x-ray intensity data that addresses these concerns and allows, to our knowledge for the first time, the use of multivariate techniques such as Partial Least-Squares (PLS) to analyze x-ray absorbance data. Further, we have been able to use NIST standard values for x-ray mass attenuation coefficients to create accurate PLS models in silico. We discuss the conditions for which the new approach is valid and demonstrate its use for the measurement of Pu and U in solutions resulting from the acid-based dissolution of nuclear fuels.
Speaker: Robert Lascola - Savannah River National Laboratory
Co-Authors
A new approach to x-ray absorbance analysis of actinides