Measurement of low enriched uranium fuel pellets

Fresh low enriched uranium fuel pellets for a nuclear reactor have been measured by a passive non destructive assay technique. It is based on the measurement of a certain characteristic gamma-rays peak of the U-235 in the pellets at energy of about 185.7 keV. The technique does not require nuclear material standards for the measurement of U-235 enrichment. The measurement employs a high resolution Ge detector gamma-ray spectrometer. The obtained values of U-235 enrichment are comparable in accuracy with results by the relative methods which require nuclear material standards. The present work may be applied as a method of control of nuclear material at the production level. Also, it can be used for nuclear material safeguards and inventory verification purposes.