Determination of microgram and submicrogram amounts of americium in spent nuclear fuel and plutonium samples by isotope dilution gamma spectrometry

A method is described for determining microgram and submicrogram amounts of americium in plutonium and spent nuclear fuels by isotope dilution gamma spectrometry (IDGS) using 243Am as the spike isotope. The gamma spectra of americium are measured after a separation on ion exchange resins in HCl and mixture of acetic and nitric acids. The gamma radiations of 59.54 keV (241Am) and 74.67 keV (243Am) are measured. 0.2 μg of americium can be determined with a relative error of < 0.9%. The results of IDGS agree within 0.4% with results obtained by isotope dilution alpha or mass spectrometry. (author)