REFERENCE MATERIALS: SELECTION OF STARTING MATERIALS

Accurate and traceable measurement values constitute and essential component on the nuclear materials control and accountability system. Reference materials constitute and important element in the measurement system. In the United States, New Brunswick Laboratory has the Paramount responsibility to prepare nuclear certified reference materials (CRMs). In this paper the discussion focuses on one aspect in the production of a certified reference material: the selection of the starting material. The quality of the starting material directly and inevitably effects the quality of the product. Compromises made in the selection of the starting material may result in a higher uncertainty associated with the certified value of the reference material; this in turn may limit the usefulness of the reference material. In my presentation, I will discuss, with examples, the desirable specifications of starting materials for the production of NBM CRMs, the possibilities, the limitations, and how they would affect the quality of nuclear material accountability measurements made in the complex. The preparation and certification of Primary Reference Materials on an international collaborative basis will also be discussed. This collaboration is an efficient and scientifically advantageous way to produce CRMs of highest quality.