NONDESTRUCTIVE ASSAY OF PLUTONIUM BEARING SCRAP AND WASTE WITH THE ADVANCED SEGMENTED GAMMA-RAY SCANNER*

Assaying plutonium-bearing scrap and waste (S&W) for plutonium content can be very difficult because of the heterogeneous nature of the items. Previous efforts have been hampered by the lack of representative standards for calibrating and evaluating measurement performance on actual plant materials. We have characterized 25 S&W items in three distinct S&W categories to 2% or better. We used these items with fabricated calibration standards to evaluate the performance of the lump-corrected segmented gamma-ray scanner. We show that some difficult-to-measure S&W samples can be assayed with less than 10% bias, but still suggest that each category of S&W be individually evaluated for measurement bias.