In nuclear safeguards, precise and accurate isotopic analyses are needed for two major elements from the nuclear fuel cycle:
uranium and plutonium. This can be achieved by Isotope Dilution Mass Spectrometry (IDMS), which is one of the most reliable
analytical techniques for the determination of plutonium amount content to a high level of accuracy. In order to achieve reliable
isotope measurements isotopic reference materials with certified amount of plutonium and isotopic composition are required.
At the Institute for Reference Materials and Measurements (IRMM) various plutonium spike reference materials for isotopes
239Pu, 240Pu, 242Pu and 244Pu are available. This enabled the setup of an inter-calibration campaign inter-linking selected plutonium spikes on a metrological
basis applying state-of-the-art measurement procedures. The aim of this campaign is threefold: firstly to perform measurements
on selected plutonium spike isotopic reference materials for quality control purposes, secondly to verify the amount content
and the isotopic composition of the recently produced IRMM-1027m large sized dried (LSD) spikes and thirdly to demonstrate
IRMM’s measurement capabilities for plutonium analysis via external quality tools. The obtained results using various spike
isotopic reference materials will be presented and discussed in this paper. The measurement uncertainties of the IDMS results
were calculated according to the guide to the expression of uncertainty in measurement (GUM).