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Development of new and improved data reduction techniques for radiometric assay of bulk uranium ore samples. Final report

Technical Report ·
OSTI ID:6571122

Techniques have been developed for the routine assay of homogeneous uranium ore samples that will yield the highest attainable precisions and accuracies to be obtained practically by conventional Ge(Li) spectrometry. Uranium, equivalent uranium (/sup 226/Ra), thorium, and potassium concentrations, uranium-radium disequilibrium, and a measure of radium--radon equilibrium can be obtained in a single measurement. The relative concentrations of /sup 222/Rn, /sup 226/Ra, /sup 235/U, and /sup 238/U are used to determine the radioactive equilibrium conditions and to allocate the observed intensity of the relatively strong unresolved peak at 186 keV in the spectrum to the separate decays of /sup 235/U and /sup 226/Ra. In routine analyses using one-hour counting times, accuracies of +-3% are readily obtainable for U in concentrations above 250 ppM and for Th in concentrations above 70 ppM. Accuracies of better than 10% can be obtained for U and Th in concentrations above 80 and 20 ppM, respectively. Spectra using a 7.6-cm by 7.6-cm NaI(Tl) were analyzed using the MAZE spectrum enhancement computer program and compared to those from Ge(Li) analyses. Accuracies of better than 10% can be obtained for equivalent U and for Th analyses using a 4000-second counting time. Precisions of about 10% can be obtained for /sup 235/U analysis using the intensity of the 186-keV peak, adjusted for the contribution from the decay of /sup 226/Ra. Precisions of about 50% can be obtained for /sup 238/U and for potassium assay. Difficulties in the present MAZE code lie in the description of the continuum and in the detector response functions. 20 figures, 13 tables.

Research Organization:
Science Applications, Inc., Rockville, MD (USA)
DOE Contract Number:
EY-76-C-13-1664
OSTI ID:
6571122
Report Number(s):
GJBX-124(78)
Country of Publication:
United States
Language:
English