PRODUCTION OF REPLACEMENT CERTIFIED REFERENCE MATERIALS FOR URANIUM OXIDE (129-A) AND PLUTONIUM METAL (126-A)

The preparation, characterization, and certification of two new replacement certified reference materials (CRMs) for nuclear safeguards accountability measurements – CRM 129-A (uranium oxide) and CRM 126-A (plutonium metal) – are described. A CRM is a well-characterized material, accompanied by a certificate, that provides certified values for one or more of its physical and/or chemical properties. CRMs are at the top of the metrological hierarchy of reference materials in the measurement system. The U.S. Department of Energy’s (DOE) New Brunswick Laboratory (NBL) is the U.S. Government’s Certifying Authority for nuclear CRMs and has recently completed several years of project work on CRMs 129-A and 126-A. CRM 126-A production was coordinated with Los Alamos National Laboratory (LANL). CRM 129-A, a highly pure normal uranium oxide standard, was analyzed for uranium concentration (assay) and isotopic abundances. CRM 126-A, a highly pure plutonium metal standard, was analyzed for plutonium concentration (assay), isotopic abundances, and impurities. Completed work and further planned work on these CRMs, for relevant information items (e.g., particle size, analysis by different analytical methods, density) will be discussed. Applications for these CRMs in the domestic and international nuclear community will also be discussed.