Non-destructive assay measurement for the verification of uranium oxide powders

A passive non-destructive assay technique is employed in the present investigation for precise measurement of U-235 enrichment of uranium oxide powders used for nuclear fuel fabrication. The technique would not require nuclear material Standards for the measurement of 235U enrichment. It uses a gamma-ray spectrometer composed of a high-resolution germanium detector system and associated electronics. A new mathematical analysis - based on Monte Carlo calculations - has been developed for the estimation of U-235 enrichment. The obtained results are found to be of comparable accuracy with the results obtained by the relative methods which necessitate the use of nuclear material Standards. This work would be very useful for nuclear material control at the production level, and for inventory verification and safeguards purposes. (C) 2000 Elsevier Science B.V. All rights reserved.