Application of PINS and GNAT to the assay of 55-gal containers of radioactive waste

Abstract

The Portable Isotropic Neutron Spectroscopy (PINS) and Gamma Neutron Assay Technique (GNAT) assay systems that were developed with funding from the office of Research and Development (NN20), were taken to the Stored Waste Examination Pilot Plant (SWEPP) facility at the Radioactive Waste Management Complex (RWMC) and applied to the assay of surrogate and Rocky Flats Plant waste contained in 55-gal drums. PINS, a portable prompt {gamma} neutron activation analysis technique, was able to identify key elements in both the surrogate and real waste so that three-main waste categories: metal, combustible material, and cemented chlorinated sludge wastes could be identified. GNAT, a {gamma}, neutron assay technique for the identification and quantification of fissioning isotopes, was able to identify {sup 240}Pu in surrogate waste in which nine 1-g nuclear accident dosimeters were inserted. GNAT was also able to identify {sup 24O}Pu in real 55-gal waste drums containing 15- and 40-g of plutonium even in the presence of high activity concentrations of {sup 241}Am.