5.1 The measurement of isotopic distributions for the lanthanide series elements is of important to all phases of the nuclear fuels cycle. Examples include the purification of the Nd isotopes from Ce and Sm isotopes for the determination of atom percent fission through the production of ¹⁴⁸Nd in irradiated nuclear fuels using Practice C1769, determination of rare earth content and isotopic distribution in Uranium Ore Concentrates (UOC) for source term and production of lanthanide fission products in irradiated nuclear fuels for determination of performance, improvements of depletion codes, and analysis of burnup indicators.3

1.1 This practice provides instructions for the rapid separation of lanthanide elements using high pressure ion chromatography (HPIC) from dissolved uranium materials such as: nuclear fuels, uranium ores, hydrolyzed UF₆, and depleted, natural, or enriched oxides/powders, or metals. When optimized, this technique will produce purified elemental fractions of the lanthanide elements isolated from the bulk uranium matrix allowing for isotopic assay using inductively coupled plasma mass spectrometry (ICP-MS).

1.2 This practice is most applicable for analyte concentrations of nanograms per gram uranium or higher. For ICP-MS detection and measurement of analyte concentrations lower than this, it would be necessary to perform additional pre-cleanup or concentration techniques, or both, which are not addressed in this practice.

1.3 When combined with isotope dilution, this practice can also be used for improved precision assays of the lanthanide elements using the principle of isotope dilution mass spectrometry (IDMS).

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this practice.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.