The present study discusses the incorporation of uranyl ion into Y-zeolite framework. The UO
sorption was measured by neutron activation analyses. The Y-zeolite framework distorts in response to the cations present in the structure. Hence, depending on the amount and the location of the exchanged cations, the features of the X-ray diffraction pattern may vary. From the Rietveld analysis of these patterns, the positions occupied by the UO
cations in the zeolite network were determined.