Synthetic and process material nondestructive assay calibration standards

Two general approaches to nondestructive assay (NDA) chemical standard preparation and certification have been successfully employed at the Rocky Flats Plant. The fabrication of synthetic standards is a low cost method of obtaining standards with well characterized special nuclear material (SNM) content, but this approach may result in instrument calibration biases due to unanticipated matrix effects. Certification of process material with chemical and/or NDA measurements requires more effort and normally results in a higher uncertainty for the SNM content. The latter approach does, however, produce standards with a matrix that is more representative of the process stream, thus improved instrument calibrations result. Examples of both calibration techniques are discussed. 7 references, 18 figures, 1 table.