Analytical Method For The Assay Of Plutonium Oxide Diferential Spectrophotometry PDF Download

A novel approach has been developed at the Los Alamos National Laboratory for the quantitative determination of moisture content in impure plutonium oxide. The method combines a commercial supercritical fluid extraction instrument using supercritical carbon dioxide (SCCO2) with on-line detection using a high-pressure Fourier Transform Infrared Spectroscopy (FTIR) cell. The combined SCCO2/FTIR system has been modified for use inside a fully enclosed glove box. A series of validation experiments were performed using a pure, surrogate oxide (ThO2) and an inorganic hydrate (CaSO4·2H2O). The level of agreement between LOI and SCCO2/FTIR for the surrogate oxide is excellent. The results for the inorganic hydrate showed excellent correlation with the known amount of water present. Results obtained for a group of nominally pure PuO2 samples were verified by independent measurement. The results of SCCO2/FTIR for impure PuO2 samples is consistently lower than the results of obtained from the current analytical method (Loss On Ignition), indicating that the current method is inadequate for analytical purposes. While further verification experiments of the SCCO2/FTIR method are underway, these initial results suggest that SCCO2/FTIR could be used as an alternative analytical method for the Materials Identification and Surveillance program.