HOLDUP MEASUREMENTS FOR VISUAL EXAMINATION GLOVEBOXES AT THE SAVANNAH RIVER SITE

Visual Examination (VE) gloveboxes are used at the Savannah River Site (SRS) to remediate transuranic waste (TRU) drums. Noncompliant items are removed before the drums undergo further characterization in preparation for shipment to the Waste Isolation Pilot Plant (WIPP). Maintaining the flow of drums through the remediation process is critical to the program’s seven-days-per-week operation. Conservative assumptions are used to ensure that glovebox contamination from this continual operation is below acceptable limits. Holdup measurements are performed in order to confirm that these assumptions are conservative. High Cs-137 backgrounds in the VE glovebox areas preclude the use of a sodium iodide spectrometer, so a high-purity germanium (HPGe) detector, having superior resolution, is used. Plutonium-239 is usually the nuclide of interest; however, Pu-241, Np-237 (including its daughter Pa-233) and Pu-238 (if detected) are typically assayed. Cs-137 and Co-60 may also be detected but are not reported since they do not contribute to the Pu-239 Fissile Gram Equivalent or Pu-239 Equivalent Curies. HEPA filters, drums and waste boxes are also assayed by the same methodology. If – for example - the HEPA is contained in a stainless steel housing, attenuation corrections must be applied for both the filter and the housing. Dimensions, detector locations, materials and densities are provided as inputs to Ortec’s ISOTOPIC software to estimate attenuation and geometry corrections for the measurement positions. This paper discusses the methodology, results and limitations of these measurements for different VE glovebox configurations.