PROGRESS AT IRMM IN THE PREPARATION OF IRMS AND EXTERNAL QC PROGRAMMES

IRMM has a well developed programme for the preparation of Isotopic Reference Materials (IRMs) and Amount Content IRMs (spikes) for Safeguards and Nuclear Materials Accountancy (NMAC) purposes /1/. With a few exceptions, a complete palette of these materials is now available for the measurement of uranium and plutonium. On-going demands lead to renewal of materials and the constant demand for higher specifications means that new materials are constantly being planned and prepared. Of major importance has been the development of low concentration materials for the analysis of environmental samples. Much work is still required to ensure the suitability and stability over long time periods of such materials. Accompanying this programme has been the preparation of materials for external QC campaigns (REIMEP). The materials used in these campaigns are certified exactly as the IRMs but used blind, i.e. sent to participating laboratories without certified values. These are sent to the laboratories on return of the measured results.