Metal spikes isotope dilution mass spectrometric analysis of spent-fuel solutions

A sufficiently homogeneous alloy of 235U and 239Pu enriched isotopes should now permit the achievement of precisions and accuracies of the order of 0.1 to 0.2% in the IDMS of uranium and plutonium in solutions of highly irradiated spent fuels under routine field conditions. The use of an internal standard with multicollection could also further improve the accuracy of the IDMS assays if the relative efficiencies of the detectors and the isotopic composition of the internal standard could be calibrated to a few 10-4