Determination of lanthanides and actinides in uranium materials by high-performance liquid chromatography with inductively coupled plasma mass spectrometric detection

The determination of Nd, U and Pu by isotope dilution analysis is well known as the classical method for the calculation of the burn-up of a nuclear fuel. Numerous isobaric overlaps restrict the direct determination of fission product and actinide isotopes by mass spectrometry and therefore an extensive chemical separation is required. As a first step towards the development of a more advanced method for the determination of fission product isotopes in irradiated uranium fuel, high-performance liquid chromatographic (HPLC) and inductively coupled plasma mass spectrometric (ICP-MS) systems were installed in glove-boxes and all the lanthanides were separated by HPLC and detected on-line by ICP-MS, As high U and Pu concentrations strongly suppress the signals of trace elements in ICP-MS, a separation method to elute U and Pu first was developed. Thus it was possible to determine the isotopic composition of Nd in a high U and Pu matrix. With the same equipment, a method was developed to prevent isobaric overlaps in the mass spectrum by separating U, Am and Pu.