Determination of 17O and 18O isotopic abundances in 238Pu materials by γ-ray spectrometry

A procedure has been developed for nondestructive determinations of ¹⁷O and ¹⁸O isotopic abundances in ²³⁸PuO₂ fuels produced for biomedical application. Close control of these isotopes is important because they increase the neutron emission rate caused by (α, n) reactions. γ-Rays accompanying these reactions are measured by a lithium-drifted germanium Ge(Li)] detector and related to their respective isotopic abundances. Each determination has a detection limit approximating the lowest contents encountered in PuO₂ samples of 0.005% ¹⁷O and 0.001% ¹⁸O. The average deviations for each determination are estimated to be about ±25% at their detection levels, and less than ± 10% for abundances above 0.01%.