SHUFFLER MEASUREMENTS OF PREVIOUSLY UNVERIFIED AND UNCONFIRMED INVENTORY ITEMS

The two new shufflers at Los Alamos National Laboratory (LANL) have been used on uranium inventory items that could not be previously verified or confined because of the lack of a suitable assay instrument. A third shuffler at the Westinghouse Savannah River Site (SRS) is currently measuring yet another inventory. One of the LANL inventories had items with only uranium while the second inventory had many mixtures of uranium and plutonium. The only calibration standads available were uniformly shaped cans of uranium oxide with no significant impurities. The inventory items had a wide variety of compositions, impurities, and geometric forms. Three measurement plans have been used with increasing sophistication as our experience and resources have grown. They are (a) semi-quantitative and (b) quantitative analyses of only the active-mode shuffler data, and (c) quantitative analyses of active- and passive-shuffler data combined with isotopics and enrichments deduced from gamma-ray measurements. Measurement results for the first two approaches for the LANL inventories m given in this pape~ results of the third approach in the SRS case will be re~rted at a later date after they are completed.