Description of Units for Material and Data Characteristics to Support a National Nuclear Forensics Library. Annex III

Using a standardized set of units for nuclear and radioactive material characteristics in a Library facilitates rapid comparative analyses. The conversion of units to a standardized set has the advantage of facilitating comparability between all materials in a Library. Additionally, if unit conversions are completed prior to entering data into a Library, a verification step can be completed to reduce the risks of unit conversion errors during Library queries. A list of units for describing material characteristics in a Library is presented. Generally, they are SI or centimetre–gram–second system units, and were selected for ease of comparing a diverse set of materials from across the fuel cycle and a wide variety of radioactive sources. It is up to each State to decide if these units are appropriate for their Library, and in some cases, where a State only has a very limited number of materials; it might be simpler to use alternative units. For example, if a State only mines uranium ore, it might be more appropriate to express uranium concentration in ore in units of g/tonne or g/kg instead of the recommended units of g/g, which are generally more useful for comparing uranium concentrations for nuclear fuel cycle materials.