Enrichment determinations on uranium dioxide powders and pellets using hyperpure germanium detectors in field conditions

The purpose of this study was to investigate the capabilities of hyperpure germanium detectors for enrichment determinations on low enrichment uranium oxide in production lines. The measurements were effected using two detectors in two geometries : with and without collimator on reference samples which fulfilled the ''infinite thickness'' condition. An external source of Eu-152 was used to define the counting time and to verify the stability of the instrument. Powders and pellets of uranium oxide with enrichment varying from 1.9 up to 4.2 % were measured in the ''Franco-Belge de Fabrication de Combustibles'' (FBFC), Dessel, Belgium. Estimations of systematic and random errors and background corrections are given for the two cases with and without collimation. Tests of the sample homogeneity and detection power of enrichment change versus declared value are fully discussed. (author)