Year
2004
Abstract
Until a commercial box counter is available for use at Hanford’s Plutonium Finishing Plant (PFP), portable instruments will be utilized to perform NDA on Standard Waste Boxes (SWB) containing TRU waste generated at PFP. This paper presents the steps that were taken to qualify the portable instruments to meet safeguards requirements. Highpurity germanium spectrometers are used for gamma measurements and slab detectors are used for neutron measurements. A test plan was prepared to describe the fabrication of a “standard” SWB, the selection of sources to be used in the qualification tests, the steps to determine the MDA, the steps to determine the isotopic composition, and the steps to determine the amount of plutonium in the SWB. A SWB was prepared that would hold the various sources in preselected, repeatable positions surrounded by a simulated waste matrix. A framework was fabricated to fit inside the SWB to hold the sources. The space around the framework was then filled with metal, plastic, and cloth to simulate the material that is expected to be loaded into the SWB’s. The gamma detectors will primarily be used to determine the isotopic composition, and the neutron system, in total counting mode, is used to determine the amount of plutonium in the SWB. This paper will discuss the standard SWB and the qualification tests. The assumptions and limitations of this method will also be discussed.