Evaluation of uncertainties in irradiated hardware characterization: Final report, September 30, 1986-March 31, 1987

Waste Management Group, Inc. has evaluated the techniques used by industry to characterize and classify irradiated hardware components for disposal. This report describes the current practices used to characterize the radionuclide content of hardware components, identifies the uncertainties associated with the techniques and practices considered, and recommends areas for improvement which could reduce uncertainty. Industry uses two different characterization methods. The first uses a combination of gamma scanning, direct sampling, underwater radiation profiling and radiochemical analysis to determine radionuclide content, while the second uses a form of activation analysis in conjunction with underwater radiation profiling. Both methods employ the determination of Cobalt 60 content, and the determination of scaling factors for hard-to-detect Part 61 radionuclides. The accurate determination of Cobalt-60 is critical since the Part 61 activation product radionuclides which affect Part 61 classification are scaled from Cobalt-60. Current uncertainties in Cobalt-60 determination can be reduced by improving underwater radiation profiling equipment and techniques. The calculational techniques used for activation analysis can also be refined to reduce the uncertainties with Cobalt-60 determination. 33 refs., 11 figs., 10 tabs