Determination of traces of americium, curium, and rare-earth elements in spent nuclear fuel by isotope dilution with mass-spectrometric detection

The procedure for determining isotopic composition and content of trace amounts (10(-10) g) of transplutonium (Am and Cm) (TPEs) and rare-earth (Nd, Sm, Eu, and Gd) (REEs) elements in irradiated materials, in particular, in spent NPP fuel is described. The procedure is based on isotope dilution analysis with mass-spectrometric determination of isotopic ratios on a standard MI-1201 mass spectrometer with modernized ion registration system equipped with a position-sensitive ion detector (PSID) with microchannel plates having a resistance-capacitive anode. In certain cases (Sm and Eu) the total content of the element was determined by luminescence analysis, and the isotopic composition, by mass spectrometry. The results of analysis of spent fuel of various NPPs by the above procedures are reported. The determination error of 10(-10)-10(-12)-g amounts of nuclide with 0.1-1.0 isotopic ratios is 2-5%.