Measurements for nuclear material accounting and control need reference materials as the foundation of the measurement processes. It is preferred to use a Certified Reference Materials (CRMs). However, CRMs prepared from nuclear materials are not always available for specific applications. In the absence of reference materials, working reference materials (WRM) are acceptable. The challenge is to develop working reference materials and quality control materials that resemble real samples. In order to have a strong measurement quality control system, the WRMs at a laboratory need to be prepared using rigorous methods. The WRMs also need to be well characterized, preferably resulting in uncertainties that are less than the uncertainty of the analytical method that will be controlled. Due to the limited availability of CRMs certified for both concentration and isotopic composition, an innovative approach for the development of WRMs was used at Savannah River National Laboratory. Working Reference Materials for uranium concentration were prepared from CRMs certified for isotopic composition. These WRMs were further characterized using the Davies Gray potentiometric method for assigning concentration values. Mass spectrometry measurements were performed to validate the concentration of the WRM and confirm the isotopic composition. The WRMs will be used to validate ICP-MS IDMS method for uranium isotopic measurements and uranium content measurements for samples with a range of isotopic compositions.
Year
2020
Abstract