Integrated five station non-destructive assay system used to support plutonium facility decommissioning

Summary form only given. Decontamination and decommissioning activities at the NFS, Erwin mixed oxide fuel fabrication facility began in June 1990. This operation is supported comprehensively with a state-of-the-art, five station non-destructive assay system. A passive neutron counter network provides a real time, on-line criticality safety monitoring at potential holdup points, with a sensitivity level of a few grams Pu. The same system provides quantitative, on-line holdup evaluation. In cell decontamination effectiveness is measured in a large (5-ft*6-ft*10-ft) pulsed neutron differential dieaway unit, operating at a sensitivity level below 10 nCi/gm (200-s assay). Compacted waste bales are quantitatively assayed in a drum size differential dieaway unit with a 1-nCi/gm sensitivity. A combined high-resolution gamma spectrometer/passive neutron coincidence counter is used to quantify Pu scrap and high-yield residues.<>