Assay of an alpha solid waste drum using passive neutron counting

A passive neutron based assaying system for plutonium bearing solid wastes has been designed and developed. The assaying of the plutonium in the drum containing the wastes is determined by as positioned and by rotating the drum to 180 degree and average counts are obtained. The average counts were used for deriving the counting statistics. This system was calibrated with plutonium typically obtained in fast reactor fuel reprocessing facilities with known isotopic compositions. The minimum detection limit has been estimated to be 35 mg. It has been determined that a γ background of up to 2000 mR/h can be tolerated without loss of accuracy.