JRC-IRMM re-characterised and issued new certificates for the entire series of uranium hexafluoride certified reference materials (IRMM-019 to IRMM-029). These CRMs represent a unique set of reference materials to be used in process control, nuclear material accountancy and safeguards verification measurements in enrichment plants.

Enrichment is one of the proliferation sensitive stages of the nuclear fuel cycle. Gaseous uranium hexafluoride (UF₆) is one of the primary forms of uranium in the nuclear fuel cycle. Safeguards authorities require for accurate measurements of uranium hexafluoride samples CRMs with small uncertainties, not only for the major isotope ratio n(²³⁵U)/n(²³⁸U) but nowadays also for the minor ratios n(²³⁴U)/n(²³⁸U) and n(²³⁶U)/n(²³⁸U). To meet these demands the JRC-IRMM re-characterised and issued new certificates for the entire IRMM-019 to IRMM-029 series, originally dating from the 1980’s-1990’s. This series covers the enrichment range from depleted (IRMM-019 to IRMM-021) to enriched uranium (IRMM-023 to IRMM-029) via natural uranium (IRMM-022). This series has been certified using a new set of calibrants in the form of gravimetrically prepared uranium nitrate solutions, in combination with recently developed measurement methods for Thermal Ionisation Mass Spectrometry (TIMS). The CRMs represent a unique set of its kind and are available from the JRC-IRMM. They are used for instrument calibration, method validation, quality control, and the assessment of method performance for isotope mass spectrometry. It is planned to make them also available in the form of uranium nitrate solutions for direct TIMS or ICP-MS measurements in the near future.

Details about the re-characterisation and certification of the IRMM-019 to IRMM-029 series of uranium hexafluoride (UF6) reference materials can be found in the certification report. The reference materials can be ordered via our online catalogue.