Actinide separations for α spectrometry using neodymium fluoride coprecipitation

A procedure was developed in which a 10-g soil sample was fused in potassium fluoride followed by a pyrosulfate fusion. The flux was dissolved in dilute hydrochloric acid and thorium, uranium, plutonium, and americium were coprecipitated on barium sulfate. The barium sulfate was dissolved and precipitated in the presence of diethylenetriaminepentaacetic acid (DTPA) to separate the actinides from barium sulfate. The filtrate was decomposed, fused in a pyrosulfate flux, and dissolved in dilute nitric acid. Thorium was separated from the other actinides by coprecipitation on ceric iodate. Uranium, plutonium, and americium were separated sequentially, one from the other, by oxidizing them to their highest oxidation states followed by a series of coprecipitations of the nuclides. The isolated nuclides were coprecipitated on neodymium fluoride, filtered, and counted by α spectrometry. The recoveries ranged from 85% to 95%. The resolution for full width at half maximum (fwhm) was between 60 and 70 keV. Decontamination factors ranged between 103 and 104. 8 references