| Abstract: | Abstract A sensitive, isotope dilution technique has been developed for the analysis of sub-microgram amounts of zirconium. The analysis is based on the increased thermal ion emission for Zr adsorbed on a single anion resin bead. Zr is isolated from a solution containing the sample and a highly enriched 94Zr (96%) spike. The determination is made possible by using a high-sensitivity pulse-counting 2-stage 30-cm radius mass spectrometer. The detection limit depends upon the amount of the isotope spike added and the desired precision. Fifty nanograms of zirconium (sample plus spike) produce sufficient ion signals for reliable isotopic analysis so that fission Zr can be measured with blank correction to a precision of 3%. By this method for fission Zr in spent reactor fuel particles, contamination from normal Zr and Mo can be corrected out by making isotopic measurements before and after spiking and scanning masses 90 and 95 during analysis. Since neither masses 90 nor 95 are stable fission products, their presence is due to sample contamination and can be used for correction based on their normal isotopic distributions. Zone-refined tantalum ribbon, essentially free of normal Zr and Mo was selected as the ionizing filament. This method can be adapted to a wide variety of samples. |
