Use of Field High Resolution Gamma Spectroscopy during Decontamination and Decommissioning of Nuclear Facilities

This paper describes the utilization and evolution of field high-resolution gamma spectroscopy (field-HRGS) during decontamination and decommissioning (D and D) of a nuclear facility; beginning with characterization of drummed and boxed radioactive waste for purpose of shipment and disposal, and ending with survey and analysis of radioactive material held-up in building fixtures and structures leading to improvements in radiation safety, environmental protection, waste disposal, and regulatory compliance. This technology also provides detailed documentation of regulatory compliant clean-up and disposal activities. Compared to other radiation detection technologies, HRGS provides the best gamma radionuclide identification capabilities for both naturally occurring radionuclides such as U-238, U-235, U-234, Th-232, Th-228, Ra-226 and their daughter products as well as other radionuclides (Pu-239, Am-241, Ba-133, Cs-137, Co-60, etc.) associated with human activities. No other technique can match the ability to quantify gamma radionuclides on an activity, mass, and concentration basis in the field as well as HRGS. HRGS is a powerful analytical tool often overlooked by industry in favor of other less costly and less complicated measurement techniques such as sodium iodide (NaI) or cadmium zinc telluride (CZT) survey. When used properly - in a coordinated effort during D and D operations, field-HRGS survey and analysis can provide large benefits in radiation and environmental protection, waste reduction, waste disposal, and regulatory compliance with anticipated lowering of risk and overall savings in cost. (authors)