For approximately 18 months, since the development of the ANL type scintillation spectrometer, we have been using the instrument in our survey work on virtually every material type of fuel that is made. I would like to point out that both the instrument and the methods developed for determing U-235 in fuel have been a success well beyond our expectations. The instrument was shown and briefly described at last year1 s meeting. Detailed specifications and drawings are available as an ANL Report No. 6123. The developments, perhaps of most importance, are the methods of determining the U-235 content, non-destructively, by gamma-ray spectroscopy.