ASSAY OF URANIUM IN CRUDE DIURANATE CAKES AND MGF2 SLAG PRODUCED AT THE NATURAL URANIUM CONVERSION PLANTS BY GAMMA-RAY SPECTROMETRY

A transmission-corrected gamma-ray counting method has been employed f or the assay of uranium in crude Na2U2O7 cakes produced at the Uranium Conversion Facilities. A 3'' x 3'' NaI(Tl) detector was used in conju nction with a 400-channel analyzer. The observed count rate of the 1 M eV gamma-ray emitted by the U-238 in the sample was corrected for samp le self- attenuation, measured with a Zn-65 (gamma-energy approximatel y 1115 keV) transmission source. A calibration factor determined by me asuring a standard of known amount of radioactive material in the same form and geometry 3S the unknown sample was used to convert the trans mission corrected count rate to the amount of uranium in the weighed s ample. Another gamma-spectrometric method is described for the assay o f the U-content in the MgF2 slag produced during the magnesiothermic r eduction of UF4 to U-metal ingots at the natural U-conversion plant.