STATUS OF PORTABLE NON DESTRUCTIVE ASSAY (NDA) AT THE PLUTONIUM FINISHING PLANT (PFP)

Collimated portable gamma-ray detectors are used to quantify the plutonium holdup in support of facility deactivation and decommissioning. The Generalized Geometry Holdup model recently has been implemented for data reduction to support a new decontamination and decommissioning mission. An approach to assess the total measurement uncertainty (TMU) has been developed. The TMU is added to the assay value for compliance with safety based limits. Details of the measurement techniques and comparisons to assays of materials removed are described.